AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 850 PM MST TUE JUN 24 2008 .SYNOPSIS...STRONG HIGH PRESSURE ALOFT WILL CONTINUE THE HOT DAYTIME TEMPERATURES ACROSS SOUTHEAST ARIZONA THROUGH THE WEEK. SOME INCREASE IN MOISTURE WILL LEAD TO A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS...MAINLY EAST AND SOUTH OF THE TUCSON METRO AREA. && .DISCUSSION...KEMX WSR-88D DETECTED SCATTERED MOSTLY LESS THAN 40 DBZ ECHOES ACROSS SRN COCHISE AND EXTREME ERN SANTA CRUZ COUNTIES AT 0345Z. THE REST OF SE AZ WAS VOID OF PRECIP ECHOES. IR SATELLITE IMAGERY INDICATED CLOUD TOPS GRADUALLY COOLING OVER NERN SONORA AND SRN COCHISE COUNTY DURING THE PAST HOUR. WATER VAPOR SATELLITE IMAGERY INDICATED CYCLONIC CIRCULATION FEATURE OVER SRN SONORA MOVING SLOWLY NWD. GOES TOTAL PRECIP WATER VALUES OVER 1.0 INCH JUST SOUTH OF THE INTERNATIONAL BORDER WITH GENERAL 0.50-0.75 INCH VALUES OVER SE AZ. 25/00Z UPPER AIR PLOTS INDICATED DIFFLUENT FLOW IN THE 300 MB LAYER OVER FAR SE AZ/SW NM/NERN SONORA REGION...WITH MID- LEVEL RIDGE AXIS ADJACENT THE ERN AZ/WRN NM BORDER. 25/00Z NAM ACCUM PRECIP FIELDS DEPICTED DRY CONDITIONS AREAWIDE AFTER 06Z AND CONTINUING THRU WED MORNING. RUC SOLUTION ALSO SIMILAR...WITH A FEW HUNDREDTHS-INCH AMOUNTS OVER SRN COCHISE COUNTY ENDING 06Z. BASED ON THE ABOVE DIAGNOSTICS...WILL MAINTAIN LOW-GRADE POPS SANTA CRUZ/COCHISE COUNTIES UNTIL 10Z WITH THE BELIEF THAT THE NWP SOLUTIONS ARE UNDERDONE. ALREADY REMOVED INHERITED POPS FOR THE WHITE MOUNTAINS/GREENLEE COUNTY/TUCSON METRO AREA FOR THIS EVENING. DEWPOINT AS OF THIS ISSUANCE 54F AT KDUG...AND WOULD NOT BE SURPRISED IF 50S DEWPOINTS WILL BE EXPERIENCED AS FAR NORTH AS KTUS TONIGHT INTO EARLY WED MORNING. BELIEVE SOME UPSWING IN ACTIVITY WILL OCCUR WED PARTICULARLY GIVEN THE EXPECTED INCREASE IN PRECIP WATER VALUES...AS WELL AS 25/00Z NAM SOLUTION OF QPF VALUES WED AFTERNOON/EVENING ACROSS COCHISE COUNTY. MADE MINOR MODIFICATION TO THE INHERITED POPS FOR WED AFTERNOON/ EVENING...AND STOPPING JUST SHORT OF CHANCE-CATEGORY POPS ACROSS COCHISE COUNTY. WILL DEFER TO MIDNIGHT SHIFT FOR ADDITIONAL REFINEMENT. THEREAFTER...LOW-GRADE POPS TUCSON METRO AREA EWD/SWD DURING THE NEXT SEVERAL AFTERNOONS AND EVENINGS WITH DRY CONDITIONS WRN SECTIONS SEEMS REASONABLE. DAYTIME MAX TEMPS SLIGHTLY ABOVE SEASONAL NORMALS FOR LATE JUNE. && .FIRE WEATHER...STRONG HIGH PRESSURE ALOFT WILL CONTINUE THROUGH THE WEEK. HOT DAYTIME TEMPERATURES WITH MINIMUM RELATIVE HUMIDITIES MAINLY IN THE SINGLE DIGITS AND TEENS FOR MOST AREAS. NO SIGNIFICANT SUSTAINED WINDS ARE EXPECTED THE NEXT SEVERAL DAYS BUT LOCALIZED BREEZES ARE EXPECTED TO DEVELOP EACH AFTERNOON WITH OCCASIONAL GUSTS TO NEAR 30 MPH. THERE WILL BE ENOUGH MID-LEVEL MOISTURE FOR A SLIGHT CHANCE OF MAINLY DRY AFTERNOON AND EARLY EVENING THUNDERSTORMS FROM TUCSON EASTWARD...ESPECIALLY IN THE HIGHER TERRAIN. ANY THUNDERSTORMS THAT DO DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE STRONG...ERRATIC...AND GUSTY WINDS. && .AVIATION...ISOLATED TSRA/SHRA VICINITY KDUG ENDING AROUND 10Z. OTHERWISE CLEAR TO PARTLY CLOUDY SKIES ACROSS SE AZ THE REST OF TONIGHT INTO WEDNESDAY MORNING. SLIGHT CHANCE TSRA VICINITY KDUG AND KOLS WEDNESDAY AFTERNOON. SURFACE WINDS GENERALLY LESS THAN 10 KTS REST OF TONIGHT INTO WEDNESDAY MORNING...THEN WLY 5-15 KTS WITH FEW GUSTS TO AROUND 20 KTS WEDNESDAY AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. $$ WEATHER.GOV/TUCSON az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 221 PM MST TUE JUN 24 2008 SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA FORECAST DISCUSSION .SYNOPSIS... HIGH PRESSURE ALOFT WILL CONTINUE TO BE THE DOMINANT WEATHER FEATURE THROUGH MOST OF THE WEEK. A SLIGHT DOWNWARD TREND IN DAYTIME HIGH TEMPERATURES IS EXPECTED WEDNESDAY AND THURSDAY BEFORE THEY REBOUND AGAIN FOR THE WEEKEND. ALSO...A SLOW INCREASE IN MEXICAN MOISTURE IS EXPECTED OVER THE EASTERN HALF OF ARIZONA...RESULTING IN A SLIGHT CHANCE OF MOUNTAIN THUNDERSTORMS WEDNESDAY THROUGH SUNDAY. && .DISCUSSION... BY MID DAY...TEMPERATURES AROUND THE CWA WERE AT OR SLIGHTLY BELOW THOSE FROM 24 HOURS AGO...WHILE THE DEW POINTS WERE A MIXED BAG. SIGNIFICANT CLOUD DEVELOPMENT NEVER HAD A CHANCE TO FORM OVER THE MOUNTAINS...AND VISIBLE IMAGERY SHOWED FLAT CUMULUS SOUTHEAST OF A CASA GRANDE TO SHOW LOW LINE. LATEST RUC PUT THE CENTER OF THE UPPER HIGH NEAR CENTRAL SONORA...AND RUNNING TO THE NORTHEAST. GFS AND NAM ALSO HAD A SIMILAR PATTERN OVER MEXICO...BUT NAM HAD A WEAK TROUGH NEAR THE WEST COAST OF BAJA CALIFORNIA TODAY. SHORT TERM MODEL OUTPUT CONTINUES THE RATHER DRY PATTERN FOR MOST OF OUR CWA. THE ONE AREA THAT LOOKS A BIT MORE PROMISING THAN OTHERS...IS ZONE 24. THIS IS THE REGION WHERE THE 850-700MB MOISTURE INCREASE TRYS TO MATERIALIZE. IN FACT...AT 700MB...DEW POINTS SURGE UPWARD TO ALMOST 2C BY EARLY THURSDAY. WE LIKE THE SLIGHTLY HIGHER PRECIP WATER VALUES THAT ECMWF SUGGEST...AND LATER SHIFTS MAY WANT TO BE A BIT MORE AGGRESSIVE WITH REGARD TO THE POPS IN THAT AREA. INTERESTING TO NOTE THE LATEST WRF TRENDS THE SURFACE DEW POINTS UPWARD...ALTHOUGH THE LOCATION AND STRENGTH OF THE THURSDAY MORNING SURGE IS NOT FAVORABLE FOR INSERTING THUNDERSTORMS FOR PHOENIX. THUS...THE FOCUS WILL BE ACROSS SOUTHERN GILA COUNTY WHERE THERE WILL BE THE SLIGHT CHANCE OF AFTERNOON AND EARLY EVENING TSTMS. TODAYS TEMPERATURES WILL LIKELY BE WARMER THAN WED/THURSDAY...BUT WITH THE UPPER HIGH SHIFTING NORTHWARD FOR THE WEEKEND AND EARLY NEXT WEEK THE MAX TEMPS WILL REBOUND ONCE AGAIN. GFS MOS CALLS FOR ABOUT 111F ON SUNDAY AND MONDAY IN PHOENIX. && .AVIATION... NO AVIATION CONCERNS THROUGH AT LEAST 18 UTC WEDNESDAY. KPHX/KIWA... ISOLATED THUNDERSTORMS ARE MOST LIKELY OVER THE HIGHER TERRAIN TO THE NORTH AND EAST OF THE GREATER PHOENIX AREA...AS WELL AS THE DESERTS TO THE SOUTHEAST. CHANCES OF THUNDERSTORMS DEVELOPING IN OR NEAR KPHX/KIWA ARE ZERO...WITH A LESS THAN 10% CHANCE OF OUTFLOW FROM DISTANT STORMS LEADING TO ANY WIND SHIFTS OR BLOWING DUST. THE CHANCES FOR THUNDERSTORMS IN AND NEAR THE GREATER PHOENIX AREA WILL INCREASE WED...AND AGAIN THU...AFTERNOON/EVENINGS. KYUM/KIPL/KBLH... CONTINUED DRY WESTERLY FLOW WITH AFTERNOON GUSTS AROUND 22KTS TODAY AND WED BETWEEN THE HOURS OF 22-03UTC. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... AN INCREASE IN LOW TO MID LEVEL MOISTURE OVER MAINLY SOUTHEAST ARIZONA IS EXPECTED TO LEAD TO SOME ISOLATED THUNDERSTORMS THERE INTO THIS EVENING. THERE IS A VERY REMOTE POSSIBILITY OF GUSTY WINDS FROM DISTANT THUNDERSTORMS AFFECTING SOUTH-CENTRAL ARIZONA THIS EVENING. MOISTURE ALOFT IS EXPECTED TO INCREASE LEADING TO A SLIGHT CHANCE OF THUNDERSTORMS OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA WEDNESDAY INTO EARLY NEXT WEEK. THE STORMS WILL BRING LITTLE IF ANY PRECIP BUT IF THEY FORM...THEY WILL BE EFFECTIVE AT PRODUCING STRONG WINDS CAPABLE OF SPREADING INTO THE LOWER DESERTS. OTHERWISE MINIMUM HUMIDITIES WILL REMAIN IN THE SINGLE DIGITS TO LOWER TEENS... ESPECIALLY IN LA PAZ AND EASTERN RIVERSIDE COUNTIES. ABOVE AVERAGE TEMPERATURES CAN BE EXPECTED INTO EARLY NEXT WEEK. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT WEATHER.GOV/PHOENIX DISCUSSION...SIPPLE AVIATION...WANEK FIRE WEATHER...AJ az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 357 AM MDT TUE JUN 24 2008 .SHORT TERM... (TODAY AND TONIGHT) SIMILAR SET UP TODAY AS YESTERDAY WITH WEAK SHORTWAVES MOVING THROUGH WESTERLY FLOW ALOFT WITHIN RATHER FLAT UPPER RIDGE ALOFT. TWO FEATURES CAN BE SEEN IN WV PICS...ONE OVER THE 4 CORNERS REGION...AND OTHER ENTERING SRN NV. AS THESE MOVE EASTWARD EXPECT ANOTHER ROUND OF AFTERNOON SHOWERS AND THUNDERSTORMS FIRING OVER THE MOUNTAINS SHORTLY BEFORE NOON...THEN SPREADING ACROSS THE SE PLAINS DURING THE AFTERNOON THROUGH EARLY EVENING. LIFT WITH THESE FEATURES APPEARS WEAKER THAN YESTERDAY...AND AIR MASS LOOKS A TAD DRIER AS WELL...SO ONCE AGAIN MAIN THREAT WILL BE GUSTY WINDS UP TO 55 MPH AND LIGHTNING. HOWEVER WITH COVERAGE APPEARING TO BE LESS THAN PAST COUPLE DAYS...EXPECT DRY THUNDERSTORMS TO BE MORE ISOLATED IN NATURE ACROSS THE WESTERN HALF OF THE FCST AREA...WITH COVERAGE TOO LOCALIZED TO WARRANT A RED FLAG. STILL COULD BE A LOCAL FIRE START THOUGH GIVEN FUEL ARE CRITICAL. ACROSS THE SOUTHEAST PLAINS...BOTH NAM AN RUC13 MIX OUT LOW LEVEL MOISTURE DURING THE AFTERNOON. THERE IS A NARROW RIBBON OF SOME 50 DEW POINTS IN THE NAM ACROSS THE FAR SE CORNER DURING THE LATE AFTN/EARLY EVENING AS LOW LVL JET CRANKS UP ACROSS THE PANHANDLES. COULD SEE SUFFICIENT CAPE IN THIS AREA FOR AN ISOLATED SEVERE STORM. MAIN THREAT WOULD BE GUSTY WINDS AND HAIL TO AROUND 3/4 INCH IN DIAMETER. DEEP LAYER SHEARS LOOK A BIT WEAKER THAN YESTERDAY...SO STORMS WILL BE RATHER PULSEY. ELSEWHERE...GUSTY WINDS AND LITTLE OR NO RAINFALL EXPECTED. MAX TEMPS SHOULD BE SIMILAR TO YESTERDAY. TONIGHT...SOME CONVECTION MAY CONTINUE ACROSS THE FAR EASTERN COUNTIES IN PROXIMITY TO LOW LVL JET THROUGH SHORTLY AFTER MIDNIGHT. NAM AND GFS HAVE BEEN OVERDOING QPF DOWN THERE PAST FEW NIGHTS...WITH CONVECTION MORE LIKELY TO SET UP FARTHER SOUTH OR EAST. THUS WILL MAINTAIN ONLY SOME LOW ISOLATED POPS IN THE SE CORNER UNTIL 09Z. -KT .LONG TERM... (WEDNESDAY THROUGH MONDAY) WX WED AND THU SHOULD BE SIMILAR TO THE LAST FEW DAYS IN THAT WE WILL SEE MOSTLY LOTS OF VIRGA OVER MOST AREAS DURING THE AFTERNOON...WITH THE BEST CHANCE OF ACCUM PRECIP OVER THE FAR EASTERN PLAINS. TEMPS WILL CONTINUE TO BE WARM...WITH HIGHS WELL INTO THE 90S ON THE PLAINS WITH 80S OVER THE HIGHER TERAIN. FRIDAYS WX WILL BE DEPENDENT ON THE FRONT MOVING TOWARDS THE REGION. BASED ON CURRENT SIMULATIONS...BELIEVE BOUNDARY WILL NOT GET INTO THE REGION UNTIL LATE AFTERNOON AT THE EARLIEST. WITH THE W FLOW INCREASING A BIT IN THE LOWER LVLS ON FRIDAY...WE SHOULD SEE LESS CLOUDS OVER THE PLAINS/MTNS. FRONT SHOULD CROSS THE REGION BY VERY EARLY SATURDAY MORNING. IT DOES NOT APPEAR TO HAVE MUCH MSTR WITH IT SO I DO NOT ANTICIPATE MUCH IN THE WAY OF LOW CLOUDS WITH IT ATTM. SATURDAY COULD BE A BIT INTERESTING. WE SHOULD HAVE INCREASED LLV MSTR OVER THE AREA AS THE HIGH BUILDS IN. IF WE CAN GET ENOUGH FLOW ALOFT WE MAY BE DEALING WITH A ROTATING STORM OR TWO OUT ON THE PLAINS. SATURDAY SHOULD ALSO BE A BIT COOLER. HOWEVER...IF IT IS TOO COOL IN THE LLLVS....WE MAY NOT SEE ANY PRECIP OVER THE REGION. SUNDAY INTO NEXT WEEK...THE HIGH AT MID LVLS BUILDS DIRECTLY OVER THE STATE. IF WE ARE FORTUNATE...WE MAY GET SOME MOISTURE TRAPPED UNDER THIS HIGH AND WE COULD GET SOME SLOW MOVING CONVECTIVE SHOWERS...HOWEVER ATTM THIS HIGH DOES NOT LOOK LIKE IT WILL BE TOO "DIRTY". /HODANISH && .AVIATION... ISOLATED TO SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS THE CENTRAL AND WESTERN PORTIONS OF SOUTHEAST COLORADO THIS AFTERNOON AND EVENING...PRODUCING VFR CIGS...GUSTY WINDS UP TO 55 MPH AND LIGHTNING...BUT LITTLE OR NO RAINFALL. FARTHER EAST NEAR THE CO/KS BORDER...ISOLATED THUNDERSTORMS WILL BE STRONGER...WITH THE POTENTIAL OF PRODUCING HEAVY RAINFALL...LOCALIZED HAIL UP TO 3/4 INCH IN DIAMETER...AND WIND GUSTS UP TO 60 MPH. THUNDERSTORMS WILL DIMINISH DURING THE EVENING WITH CLEARING SKIES. WINDS WILL FOLLOW NORMAL DIURNAL TRENDS...WITH THE EXCEPTION OF NEAR THUNDERSTORMS WHERE ERRATIC AND GUSTY WINDS ARE EXPECTED. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 31/34 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 941 PM EDT WED JUN 25 2008 .SYNOPSIS... HIGH PRESSURE WILL MOVE EAST OF THE REGION TONIGHT AS A WARM FRONT AND UPPER LEVEL DISTURBANCE APPROACH FROM THE OHIO VALLEY. THESE FEATURES WILL BRING SHOWERS AND THUNDERSTORMS THURSDAY MORNING. A TROUGH OF LOW PRESSURE MAY TRIGGER ADDITIONAL THUNDERSTORMS DURING THE AFTERNOON AND EARLY EVENING...SOME OF WHICH MAY BE SEVERE. HIGH PRESSURE WILL BRIEFLY BUILD BACK IN FOR FRIDAY...HOWEVER MORE INCLEMENT WEATHER IS IN STORE FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... QUICK UPDATE TO ACCOUNT FOR CURRENT TRENDS IN TEMPS AND DEWPOINTS...WHICH HAVE BEEN FOLLOWING METMOS VALUES QUITE NICELY THUS FAR THIS EVENING. HIGH LEVEL CLOUDS WILL CONTINUE TO INCREASE AHEAD OF DEVELOPING MCS ACROSS OHIO...WHICH HAS CLOUD TOPS COOL CLOSE TO -70 C OVER THE PAST FEW HOURS OVER WESTERN OHIO. MUCH OF THIS ACTIVITY SHOULD CURVE WELL SOUTH OF THE AREA...AS THE ACTIVITY WILL LIKELY FOLLOW THE THICKNESS PATTERN. HOWEVER...BOTH THE LATEST NAM12 AND RUC13 DATA SHOW ADDITIONAL SHOWERS/ELEVATED T-STORM ACTIVITY TO DEVELOP TO NORTH OF THIS MCS ACROSS SOUTHERN ONTARIO...AND THIS IDEA IS SUPPORTED BY THE INCREASING LOW LEVEL JET EVIDENT ON THE KDTX AND KBUF 00Z SOUNDINGS. THIS LOOSELY ORGANIZED ACTIVITY WILL EVENTUALLY TRAVERSE NEW YORK STATE FOR THE SECOND HALF OF THE OVERNIGHT AND COULD BEGIN IMPACTING THE WESTERN ZONES PRIOR TO SUNRISE...SO HAVE INCLUDED CHC POPS IN THESE AREAS TO ACCOUNT FOR THIS. HAVE KEPT MINS ALONE...AS OUR CURRENT FORECAST LOWS SEEM TO BE IN LINE WITH LATEST STATISTICAL PROG NUMBERS. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... SEVERAL UNCERTAINTIES EXIST REGARDING THE FORECAST FOR THUR. THE MAIN QUESTION FOR THE MORNING HOURS WILL INEVITABLY BE HOW THE MCV EVOLVES. IF A WIDESPREAD RAIN SHIELD FORMS...THIS COULD STABILIZE THE ENVIRONMENT FOR MUCH OF THE REST OF THE DAY. FOR NOW WILL MENTION LIKELY POPS SOUTH OF ALBANY...WITH HIGH CHANCE NORTHWARD. BOTH NAM/GFS SUGGESTING THE HIGHEST PROBABILITY FOR A CONVECTIVE COMPLEX ASSOC WITH THE MCV TO MOVE THROUGH WILL BE ACROSS SOUTHERN AREAS. THERE IS A POTENTIAL FOR SEVERE THUNDERSTORMS THUR AFTERNOON INTO THE EARLY EVENING...HOWEVER THIS THREAT IS CONDITIONAL. DEVELOPMENT WILL BE HIGHLY DEPENDENT ON HOW MUCH DE-STABILIZATION CAN OCCUR AFTER THE INITIAL MCV OR WHATEVER IS LEFT OF THIS FEATURE MOVES THROUGH. THERE MAY BE JUST ENOUGH SUBSIDENCE IN ITS WAKE TO ALLOW FOR SOME BREAKS OF SUNSHINE LATE MORNING/EARLY AFTERNOON TIME FRAME TO ALLOW FOR SBCAPE VALUES TO EXCEED 1000 J/KG. SHOULD THIS OCCUR...OTHER PARAMETERS WILL BE IN PLACE FOR STORMS TO BECOME SEVERE. LOW LEVEL MOISTURE WILL BE INCREASING THROUGH THE DAY...AND 0-6 KM BULK SHEAR WILL BE IN THE 30-40 KT RANGE WHICH WOULD SUPPORT BOWING SEGMENTS AND ORGANIZED MULTICELL CLUSTERS. ALSO...THE SHORT WAVE CURRENTLY OVER ILLINOIS EVEN IN A WEAKENED STATE MAY BE A FACTOR AND PROMOTE FORCING...AS WELL AS A HINT OF A SURFACE TROF MOVING THROUGH. THIS IS HIGHLY DEPENDENT ON HOW MUCH INSTABILITY CAN BUILD THOUGH. SPC HAS AREA IN SLIGHT RISK...AND WILL MENTION THREAT IN HWO. CONVECTIVE ACTIVITY SHOULD DIMINISH AFTER SUNSET...DUE TO LOSS OF DAYTIME HEATING AND WEAK HIGH PRESSURE BUILDING IN. WILL KEEP FORECAST DRY OVERNIGHT THUR THROUGH FRI FOR MUCH OF THE AREA. NAM HINTING AT A WEAK BOUNDARY POSSIBLE GENERATING ENOUGH LOW LEVEL CONVERGENCE FOR ISOLD STORMS ACROSS SOUTHERN AREAS. OTHERWISE IT WILL BE A WARM DAY WITH AIR MASS IN WAKE OF THURSDAY/S SYSTEM EVEN WARMER...AND WITH WESTERLY FLOW ENHANCING DOWNSLOPE POTENTIAL IN NORTH-SOUTH ORIENTED VALLEYS. YET MORE UNSETTLED WEATHER IN STORE FOR LATE FRI NIGHT INTO SAT...AS A MORE SIGNIFICANT AND SLOWER MOVING WARM FRONT APPROACHES FROM THE GREAT LAKES/OHIO VALLEY. WILL MENTION HIGH CHANCE POPS STARTING EARLY SAT MORNING...LASTING THROUGH THE DAY. UNCERTAINTY EXISTS AS TO HOW FAR NORTH THE FRONT WILL PROGRESS DURING THE AFTERNOON...WITH THE POTENTIAL FOR ROBUST CONVECTION IN THE WARM SECTOR...MAINLY FROM ALBANY SOUTHWARD AS IT SEEMS NOW. TEMPS WILL BE AFFECTED AS WELL...WITH READINGS POSSIBLY ENDING UP EITHER COOLER OR WARMER THAN FORECAST. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... QUITE AN UNSETTLED EXTENDED PERIOD LOOKS TO BE SHAPING UP FOR EASTERN NEW YORK AND WESTERN NEW ENGLAND. THE PERIOD BEGINS WITH AN OCCLUDED FRONTAL BOUNDARY ATTEMPTING TO MAKE A RUN AT THE REGION WHILE A DEEP CUTOFF LOW SLOWLY PUSHES EASTWARD ACROSS THE GREAT LAKES. HAVE KEPT POPS AT LIKELY FOR SAT NIGHT INTO SUNDAY FOR EXPECTED SHOWERS AND THUNDERSTORMS. ALTHOUGH THERE IS A DECENT AMOUNT OF UNI-DIRECTIONAL DEEP LAYER SHEAR /AROUND 30 KTS/...BIGGEST THREAT WITH CONVECTION WILL PROBABLY BE HEAVY RAINFALL. GEFS PWATS LOOKS TO BE 1-2 STDS ABOVE NORMAL...AND ALONG WITH A DEEP WARM LAYER (FRZ LEVEL AROUND 14000 FT)...COULD EXPECT SOME VERY HEAVY RAINFALL RATES. OCCLUDED FRONT SHOULD PASS THROUGH THE REGION ON SUNDAY NIGHT...SO HAVE TAPERED POPS DOWN FROM LIKELY DOWN TO CHC AFTER 00Z MONDAY. SOME DIFFERENCES BETWEEN THE 12Z ECMWF AND 12Z GFS REGARDING THE PATTERN FOR MONDAY THROUGH WEDNESDAY. THE ECMWF IS MUCH FASTER WITH LIFTING OUT AND WEAKENING THE UPPER LOW OVER THE GREAT LAKES AREA...WHILE THE GFS KEEPS THE UPPER LOW OVER THE EASTERN LAKES RIGHT INTO EARLY NEXT WEEK. EVEN WHILE THE ECMWF WEAKENS THE CUTOFF...IT STILL KEEP A RATHER LARGE TROUGH SITTING OVER THE EASTERN SEABOARD THROUGH THE FIRST COUPLE DAYS OF NEXT WEEK. HAVE GENERALLY GONE WITH HPC GUIDANCE WHICH FAVORS THE ECMWF IDEA. CAN EXPECT SCT DIURNAL CONVECTION DUE TO THE COLD POOL ALOFT AND DAYTIME HEATING THROUGH AT LEAST MONDAY AND TUESDAY. 850 TEMPS WILL BOTTOM OUT TO AROUND 10 DEGREES C ON MONDAY...AND SLOWLY IMPROVE THROUGHOUT THE WEEK. THIS WILL KEEP HIGHS RATHER COOL ON MONDAY WITH UPPER 60S IN THE HIGHER TERRAIN AND LOWER 70S IN THE VALLEYS...ALTHOUGH MAX TEMPS SHOULD IMPROVE SEVERAL DEGREES EACH DAY DURING THE WEEK AS HEIGHTS SLOWLY IMPROVE. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... HIGH CLOUDS WILL CONTINUE TO INCREASE ACROSS THE REGION DURING MUCH OF THE OVERNIGHT HOURS WITH VFR CONDITIONS CONTINUING. THE ONLY EXCEPTION MAY BE AT KGFL...WHERE TEMPS DROPPING OFF QUICKLY MAY COMBINE WITH THE LOCAL TERRAIN...LIGHT WINDS...AND NEARBY MOISTURE SOURCES OFF LAKE GEORGE AND THE UPPER HUDSON TO ALLOW FOR SOME LIGHT MVFR FOG TO DEVELOP AT TIMES AFTER 07Z. JUST PRIOR TO SUNRISE...AN AREA OF SHOWERS...AND EVEN SOME EMBEDDED THUNDERSTORMS...WILL MOVE ACROSS THE EASTERN NY TERMINALS. THIS COULD TEMPORARILY DROP VSBYS TO HIGH END MVFR LEVELS...ALTHOUGH CIGS SHOULD STAY VFR MUCH OF THE TIME. THIS SHOWER ACTIVITY SHOULD END BY MID TO LATE MORNING...ALTHOUGH SCT SHOWERS OR THUNDERSTORMS COULD REDEVELOP ONCE AGAIN FOR THURSDAY AFTERNOON...CAUSING BRIEF LOCALIZED REDUCTIONS. WINDS WILL GENERALLY BE LIGHT OVERNIGHT...WITH SOUTHERLY WINDS INCREASING FOR 5-10 KTS BY THURSDAY AFTN. OUTLOOK... FRI...VFR...ISOLD PM -SHRA/TSRA KALB SOUTH. SAT...VFR/MVFR...CHC PM SHRA/TSRA. SUN-MON...MVFR/IFR...CHC SHRAS/TSRAS. && .FIRE WEATHER... HIGH PRESSURE WILL MOVE EAST OF THE REGION TONIGHT AS A WARM FRONT AND UPPER LEVEL DISTURBANCE APPROACH FROM THE OHIO VALLEY. THESE FEATURES WILL BRING SHOWERS AND THUNDERSTORMS THURSDAY MORNING. A TROUGH OF LOW PRESSURE MAY TRIGGER ADDITIONAL THUNDERSTORMS DURING THE AFTERNOON AND EARLY EVENING. HIGH PRESSURE WILL BRIEFLY BUILD BACK IN FOR FRIDAY WITH DRY WEATHER. RELATIVE HUMIDITIES WILL RECOVER TO BETWEEN 85 AND 100 PERCENT TONIGHT...WITH VALUES ON THURSDAY ONLY DROPPING TO BETWEEN 50 AND 65 PERCENT DUE TO MOSTLY CLOUDY SKIES AND SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. WINDS WILL BE LIGHT AND VARIABLE TONIGHT...BECOMING SOUTH AROUND 5 TO 10 MPH THURSDAY MORNING...THEN SHIFTING TO THE SOUTHWEST LATE IN THE DAY AND INCREASING TO 10 TO 15 MPH. && .HYDROLOGY... A WARM FRONT AND PREFRONTAL TROUGH WILL BRING SOME SHOWERS AND THUNDERSTORMS ON THURSDAY. SOME OF THE THUNDERSTORMS MAY PRODUCE SOME BRIEF DOWNPOURS IMPACTING POORLY DRAINED AREAS...AND SMALL STREAMS. LOCALIZED RAINFALL WILL RANGE FROM A TENTH TO A HALF INCH. A VERY UNSETTLED PATTERN THIS UPCOMING WEEKEND INTO EARLY NEXT WEEK AS A SLOW MOVING COLD FRONT DRIFTS THROUGH THE REGION...PROVIDING A CONSTANT FOCUS FOR SHOWERS AND THUNDERSTORMS. THE FRONT WILL EXIT OFFSHORE NEW ENGLAND THE BEGINNING OF NEXT WEEK. MAIN STEM RIVERS SHOULD BE FINE...BUT ANY SHOWERS OR THUNDERSTORMS SATURDAY THROUGH TUESDAY COULD PRODUCE A QUICK COUPLE INCHES OF RAINFALL...WITH SOME LOCALIZED AMOUNTS POTENTIALLY OVER 2 INCHES THROUGH THE MULTI DAY EPISODE. RURAL/URBAN AND SMALL STREAM FLOODING WILL HAVE TO BE MONITORED WITH REPEATED CONVECTION IN SIMILAR AREAS. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...JPV NEAR TERM...FRUGIS SHORT TERM...JPV LONG TERM...FRUGIS AVIATION...FRUGIS FIRE WEATHER...JPV HYDROLOGY...NAS ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 251 AM EDT WED JUN 25 2008 .DISCUSSION... CURRENTLY-TODAY...TROPICAL WAVE CURRENTLY ANALYZED BY TAFB VICINITY EASTERN CUBA AND SOUTHWARD WILL CONTINUE TO PUSH WESTWARD IN TRADE WIND BELT OVER THE CARIBBEAN. SUBTROPICAL RIDGE WITH AXIS JUST NORTH OF CANAVERAL WILL CONTINUE TO NUDGE NORTHWARD AS TROUGH WEAKENS OFF THE EASTERN SEABOARD. THIS WILL LEAD TO A DEVELOPING LIGHT ONSHORE GRADIENT FLOW AND KEEP THE LOW LEVELS MOIST. WATER VAPOR LOOP/RUC ANALYSIS SHOWS UPPER LEVEL TROUGH OVER THE GULF PRODUCING A MOISTURE PLUME FROM THE YUCATAN ACROSS THE FLORIDA PENINSULA. THIS MOIST ONSHORE FLOW REGIME FAVORS NIGHT/MORNING CONVECTION ALONG THE COAST WITH AFTERNOON STORMS SHIFTING TO THE INTERIOR AND WEST COAST. THERE HAS BEEN JUST A LITTLE CONVECTION AROUND GRAND BAHAMA EARLY THIS MORNING SO HAVE LOWERED COASTAL POPS CONSIDERABLY FROM OUR CURRENT 60-70 PERCENT VALUES. THE LATEST MOS POPS ARE ONLY AROUND 40 PERCENT AREAWIDE. THIS SEEMS TOO LOW FOR THE INTERIOR SINCE MID LEVEL TEMPS ARE FORECAST TO REMAIN QUITE COOL (MINUS 9-10 DEGREES AT 500 MB). NEVERTHELESS...WILL ONLY GO A LITTLE ABOVE MOS POPS FOR THE INTERIOR. THINK THAT THE STRONGEST BOUNDARY INTERACTIONS WILL SHIFT FURTHER WEST TODAY AS EAST COAST SEA BREEZE PUSHES ACROSS THE PENINSULA A LITTLE QUICKER THAN YESTERDAY. GREATEST CHANCE FOR STRONG-SEVERE STORMS SHOULD BE IN THE FAR INTERIOR NORTHWEST. TONIGHT...ONSHORE FLOW WILL BE WEAK SO THE PROSPECTS FOR CONVECTION ALONG THE COAST WILL BE LOW AND MAINLY IN THE SOUTH. EXPECT EVENING CONVECTION WILL MAINLY SHIFT INTO WEST CENTRAL FLORIDA. THEREFORE WILL ONLY CARRY AN AREAWIDE 20 PERCENT POP. THU-TUE...RIDGE OF HIGH PRESSURE EXTENDING FROM THE WESTERN ATLANTIC (SARGASSO SEA) ACROSS CENTRAL FLORIDA AND INTO THE EASTERN GULF ON THURSDAY DROPS DOWN TO SOUTHERN FLORIDA SUNDAY AND REMAINS SOUTH OF THE AREA MONDAY AND TUESDAY AS A COOL FRONT SLOWLY MOVES ACROSS THE DEEP SOUTH. POSITION OF THE RIDGE AXIS WILL KEEP WINDS OUT OF THE SOUTHWEST FROM CAPE CANAVERAL NORTHWARD AND ONSHORE SOUTH OF THE CAPE THROUGH THE WEEKEND THEN UNIFORMLY SOUTHWEST/OFFSHORE MONDAY AND TUESDAY. WITH AN OFFSHORE FLOW PINNING STORMS TO THE EAST COAST FEEL THAT A 30 POP EVENING POP MORE APPROPRIATE FOR THE COASTAL AND NEARSHORE WATERS MONDAY/TUESDAY RATHER THAN THE STOCK/STANDARD 20 PERCENT/ISOLATED EARLY EVENING STORMS. DAYTIME HIGH TEMPERATURES SHOULD REACH THEIR CLIMO VALUES UPPER 80S/LOWER 90S BEFORE SKIES CLOUD OVER WITH MID/UPPER CLOUDINESS FROM THE STORMS. && .AVIATION...SIMILAR PATTERN TO YESTERDAY EXCEPT THAT SEA BREEZE WILL PUSH INLAND A LITTLE FASTER. HAVE SHORT TEMPO GROUPS FOR INLAND TERMINALS BUT STRONGEST STORMS THAT OCCUR DUE TO INTERACTION OF EAST/WEST COAST BOUNDARIES SHOULD BE WEST OF THE TERMINALS... EXCEPT MAYBE FOR KLEE. HAVE SHORT PROB30 GROUPS DURING THE EARLY AFTERNOON ALONG THE COAST...BUT AGAIN LIKE YESTERDAY...THINK THAT MID/HIGH CLOUDS WILL DELAY HEATING SLIGHTLY AND CONVECTIVE INITIATION SHOULD BE JUST INLAND OF THE COASTAL TERMINALS. && .MARINE...THROUGH TONIGHT THERE WILL BE A SLIGHT INCREASE IN ONSHORE FLOW EXCEPT NEAR THE LOW LEVEL RIDGE AXIS IN THE NORTH WHERE WINDS SHOULD CONTINUE AROUND 5 KNOTS. STILL SEA HEIGHTS SHOULD BE 3 FEET OR LESS. EXPECT SOME CONVECTION TO FORM ESPECIALLY ACROSS THE SOUTH BUT COVERAGE NOT MORE THAN SCATTERED. THU-SUN...WITH SURFACE-700MB RIDGE AXIS LYING OVER THE AREA EXPECT LIGHT WINDS WITH A SEA BREEZE COMPONENT EACH AFTERNOON. SEAS SHOULD BE NO MORE THAN 4 FEET OFFSHORE. && .PRELIMINARY POINT TEMPS/POPS... DAB 91 71 88 72 / 30 20 50 20 MCO 91 74 91 73 / 50 20 50 20 MLB 89 75 89 73 / 30 20 40 20 VRB 89 73 90 74 / 30 20 40 20 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...LASCODY LONG TERM....WIMMER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 148 PM EDT TUE JUN 24 2008 .SYNOPSIS... A WEAK FRONTAL BOUNDARY WILL REMAIN STALLED NEAR OR JUST INLAND OF THE COAST THROUGH WEDNESDAY MORNING...WHILE HIGH PRESSURE MOVES INTO THE REGION. A WEAK TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE CAROLINAS THURSDAY INTO FRIDAY AND REMAIN IN PLACE THROUGH THE START OF NEXT WEEK. ANOTHER FRONTAL SYSTEM WILL APPROACH FROM THE NORTHWEST FRIDAY...STALLING OUT JUST WEST OF THE AREA OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPPER TROUGH AXIS STRETCHING FROM THE NEW ENGLAND STATES SOUTHWARD INTO THE MID ATLANTIC WILL BE MOVING OFFSHORE TODAY. WATER VAPOR IMAGERY INDICATES A SWATH OF DRY AIR ROUNDING THE BASE OF THE UPPER TROUGH THAT WILL WILL SUPPORT A FAIRLY SIGNIFICANT CAP OF 5 TO 6 DEGREES THIS AFTERNOON. MODIFIED MORNING SOUNDINGS SUGGEST THAT CONVECTIVE POTENTIAL WILL BE QUITE LIMITED BY THIS DRIER AIR AND WEAK WIND FIELDS. UPPER RIDGING WILL ALSO BE GRADUALLY REBUILDING OVER THE SOUTHEAST...LIMITING ANY FORCING MECHANISM TO THE SEABREEZE. OFFSHORE FLOW IN THE LOW TO MID LEVELS SUGGEST THAT THE SEABREEZE WILL BE PINNED TO THE COAST FOR THE MAJORITY OF THE DAY. GFS...NAM AND LOCAL WRF DO NOT SHOW PRECIP DEVELOPMENT THIS AFTERNOON AS A RESULT OF THE PATTERN CHANGE. ONLY RUC INDICATES SOME ISOLATED CONVECTION INITIATING ALONG THE SEABREEZE LATER TODAY. THERE WILL BE MODERATE INSTABILITY THIS AFTERNOON...WITH MODELS SHOWING CAPE VALUES UP TO 2800 J/KG AND LIFTED INDICES DOWN TO -5. IF THE CAP CAN BE BROKEN...THEN THERE WILL BE ENOUGH INSTABILITY TO ALLOW FOR VERY ISOLATED THUNDERSTORMS TO INITIATE WITH LITTLE ORGANIZATION ALONG THE PINNED SEABREEZE. HAVE DECIDED TO KEEP POPS BELOW 15 PERCENT AND HANDLE ANY SHORT-LIVED WEAK THUNDERSTORMS WITH SHORT TERM FORECASTS. ONGOING FORECAST HIGHS LOOK ON TRACK WITH LATEST GUIDANCE AND THICKNESS VALUES. EXPECT TEMPERATURES TO REACH THE MID TO UPPER 90S AWAY FROM THE LOCALLY COOLER COASTLINE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... MAINLY A TEMPERATURE FORECAST TONIGHT...AS WINDS WILL BE FAIRLY LIGHT AND SKIES MAINLY CLEAR. WITH THE LOSS OF HEATING AND MIXING...DEWPOINT TEMPERATURES INLAND SHOULD FAIRLY QUICKLY RISE BACK INTO THE 60S THIS EVENING. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... THE WEAK FRONTAL BOUNDARY LINGERING OVER OR JUST INLAND FROM THE COAST WILL NOW BEGIN TO GRADUALLY LIFT N AS A WARM FRONT WED-THU. IN THE MEANTIME...UPPER LEVEL RIDGING WILL SLIDE E OVER THE AREA...WITH ITS ELONGATED CENTER STRETCHING FROM CENTRAL GA TO THE GA COAST. THE WRF DEPICTS SOME AFTN CONVECTION WELL INLAND ALONG THE SEA BREEZE WED AFTN BUT AM NOT INCLINED TO BUY INTO THAT SOLUTION WITH RIDGING ALOFT LEADING TO FAIRLY GOOD CAPPING AND A MOISTURE COLUMN NOT QUITE AS DEEP AS IN PAST DAYS. ALTHOUGH THERE IS A SMALL CHANCE /10 PERCENT/ THAT CONVECTIVE STORMS COULD BREAK ALONG THE SEA BREEZE...COVERAGE WILL BE SO SPARSE IF ANYTHING DOES BREAK OUT SO AM PREFERRING TO KEEP PRECIP OUT OF THE FORECAST ATTM. WILL ADMIT THAT THE WRF HAS PERFORMED QUITE WELL OVER THE PAST FEW DAYS WITH THE CONVECTION IN PINPOINTING LOCATION/TIMING...SO THIS BEARS WATCHING. AS THE FRONT LIFTS N THU...SFC HIGH PRES WILL CENTER ITSELF OVER THE ATLC ALONG WITH THE CENTER OF THE UPPER LEVEL RIDGE...MAKING FOR A DEEPER SLY RETURN FLOW AND MOISTURE INCREASING FROM S TO N. ANTICIPATING THE DIURNAL SEA BREEZE...THIS WOULD LEAD TO ISOLD-SCT CONVECTION THU AFTN AND EVE. GIVEN THE DEEPER MOISTURE FURTHER S ALONG WITH A WEAKER CAP AND HINTS OF A LEE SIDE SFC TROUGH...AM THINKING THAT THE BEST CHANCES /ALBEIT ONLY 20 PERCENT/ FOR PRECIP WOULD BE CLOSE TO THE ALTAMAHA RIVER WITH LESSER CHANCES GOING N...INCLUDING AN UNMENTIONABLE 10 PERCENT NEAR THE CHARLESTON METRO AREA. A DISTINCT PATTERN CHANGE COMES STARTING FRI AS A POTENT UPPER LEVEL TROUGH DIGS INTO THE UPPER PLAINS AND SHIFT E TO THE GREAT LAKES FRI-MON. AS THIS TROUGH DEEPENS...SO WILL MOISTURE OVER THE AREA DUE TO THE S-SW FLOW ON THE BACKSIDE OF THE ATLC HIGH. IN ADDITION... THE LEE SIDE TROUGH WILL BE FIRMLY IN PLACE WHILE ANOTHER SFC FRONTAL BOUNDARY DROPS THROUGH THE MID MISS RIVER VALLEY AND THE OH/TN RIVER VALLEYS THROUGH THE WEEKEND. ALTHOUGH THE FRONTAL BOUNDARY WILL REMAIN TO THE NW OF THE AREA...A NOTICEABLE INCREASE IN WIND FIELDS WILL AID IN MORE WIDESPREAD CONVECTIVE DEVELOPMENT EACH DAY. ADD IN THE EVER PRESENT DIURNAL SEA BREEZE TO THE MIX AND THE INGREDIENTS ARE THERE TO HAVE ANOTHER WET WEEKEND. HAVE NUDGED POPS UP TO 40S FOR FRI-SAT WITH 30S THEREAFTER. OF NOTE IS THAT MEX MODEL POPS ARE APPROACHING 50...BUT DID NOT WANT TO MAKE SUCH A BIG JUMP ATTM. WITH THE AREA REMAINING RATHER DRY AND AN UPPER LEVEL RIDGE MAINTAINING ITS PRESENCE THROUGH THU...MAX TEMPS WILL PERSIST IN THE MID 90S AWAY FROM THE COAST. DEWPOINTS LOOK TO REMAIN IN THE MID 60S WED...LEADING TO HEAT INDEX VALUES IN THE UPPER 90S. HOWEVER... DEWPOINTS BEGIN TO INCREASE ON THU-FRI...SO HEAT INDEX VALUES MAY ECLIPSE 100 FOR MANY AREAS ON THU. EVEN ON FRI...WITH MAX TEMPS IN THE LOWER 90S...HEAT INDEX VALUES MAY REACH NEAR 100 AS DEWPOINTS REACH ABOVE 70 WITHIN THE RETURN FLOW. MAX TEMPS DROP CLOSER TO 90 OVER THE WEEKEND WITH THE CLOUD/RAIN COMPLICATIONS EXPECTED. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... SCATTERED MID LEVEL CUMULUS CLOUDS WILL CONTINUE TO DEVELOP THIS AFTERNOON...HOWEVER THUNDERSTORM CHANCES WILL REMAIN QUITE LOW WITHIN A DRIER AIRMASS. WINDS WILL BACK TO THE SOUTH AFTER 20Z...AS A PINNED SEABREEZE DEVELOPS. CLEAR SKIES AND DIMINISHING WINDS OVERNIGHT SUGGESTS THAT SOME RESIDUAL LOW LEVEL MOISTURE COULD BECOME TRAPPED BENEATH THE INVERSION. ALL LATEST GUIDANCE INDICATES A SLIGHT REDUCTION IN VSBY AT KCHS AFTER MIDNIGHT...SO HAVE INCLUDED A TEMPO GROUP FOR MVFR VSBYS BETWEEN 09Z AND 12Z. LESS CONFIDENCE IN FOG DEVELOPMENT AT KSAV...SO HAVE KEPT CONDITIONS VFR AT THAT TAF SITE. DAYTIME SCENARIO FOR WEDNESDAY WILL BE SIMILAR TO TODAY...WITH SOUTHWEST WINDS BECOMING SOUTH IN THE AFTERNOON AND SCATTERED CUMULUS INCREASING OVER THE TERMINALS. EXTENDED AVIATION OUTLOOK...GENERALLY VFR CONDITIONS ARE EXPECTED INTO EARLY THURSDAY...WITH OCCASIONAL MVFR CONDITIONS POSSIBLE IN ANY AFTERNOON/EVENING SHRA/TSRA THAT DEVELOP FROM LATE THURSDAY THROUGH SATURDAY. GREATER CHANCE OF MVFR WEATHER IN CONVECTION ON SUNDAY. && .MARINE... LATEST BUOY OBSERVATIONS INDICATE WIND DIRECTIONS GENERALLY FROM THE WEST...WITH SPEEDS HAVING DECREASED TO 15 KT OR LESS. WINDS WILL BACK TO THE SOUTH-SOUTHEAST BY LATE AFTERNOON WITH SEABREEZE DEVELOPMENT. SEAS WILL RANGE FROM 2 TO 4 FT ACROSS THE COASTAL WATERS. WILL MAKE ONLY MINOR TWEAKS TO THE WORDING OF THE COASTAL FORECAST WITH THE MORNING UPDATE. WILL MAINTAIN ALL CONDITIONS BELOW SCA CRITERIA FROM THE MIDDLE OF THIS WEEK THROUGH THE START OF NEXT WEEK AS NO DISCERNIBLE SYSTEMS ARE FORECAST TO MOVE THROUGH THE COASTAL WATERS. THAT BEING SAID...A FRONTAL SYSTEM WILL APPROACH FROM THE NW OVER THE WEEKEND AND STALL INLAND OF THE WATERS. SHOULD ENOUGH PINCHING OF THE GRADIENT OCCUR AHEAD OF THIS BOUNDARY...THEN WINDS MAY REACH ABOVE THE 15 KT AREA. THE OTHER FACTOR IS NOCTURNAL SURGING...WHICH IS DEPICTED EACH NIGHT THROUGH THE WEEKEND. AGAIN...WILL KEEP WINDS BELOW SCA LEVELS BUT WINDS LIKELY WILL REACH 15-20 KT AT TIMES. AS FOR SEAS...WILL CAP WAVE HEIGHTS AT 5 FT THROUGH THE REST OF THE WEEK INTO THE WEEKEND. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 855 PM CDT WED JUN 25 2008 .EVENING UPDATE OF PUBLIC FORECAST DISCUSSION... WILL BE ISSUING AN EVENING UPDATE OF ZFP PACKAGE. ONE CHG WILL BE TO UP DEW POINTS AS PER OBS AND FOLLOW WITH SLIGHT INCR IN FCST OVERNIGHT LOWS. LGT WSWLY SFC FLOW HAS ALLOWED DEW POINTS AT OR JUST ABOVE 70 DEG TO FILTER INTO WRN AND SRN PORTIONS OF FA. OF GREATER CONCERN THOUGH...ARE POPS/WX. WILL BE ADJUSTING OVERNIGHT POPS TO CURRENT RADAR/SATLT TRENDS. WITH LOSS OF DAYTIME HEATING...THREAT OF ISOLD TSTMS OVR FA HAS DIMINISHED. HOWEVER...TSTM COMPLEX CONTINUES TO EVOLVE OVR IA. LLVL WIND FIELD OVR NRN IL/NWRN IND IS FCST TO RMN UNFAVORABLE FOR CONTINUED DVLPMT INTO FA AS WINDS AOB H85 ARE FCST TO RMN LGT WNWLY OVERNIGHT...THEN BEGIN TO BACK INTO SW ON THUR. ALTHOUGH WIND PROFILES ARE NOT CONDUCIVE TO MCS PROPAGATING FWD ACROSS NRN IL/NWRN IND OVERNIGHT...AMS REMAINS QUITE UNSTABLE AND EXPECT SOME DISCRETE STMS TO FIRE ESEWD OF STNRY/BACKBUILDING COMPLEX OVR IA. THEREFORE HAVE BUMPED UP POPS OVR SWRN PORTION OF FA FOR OVERNIGHT. WILL KEEP CHC POPS RMNDR ARE FOR PRE DAWN HRS. MERZLOCK && .DISCUSSION... 247 PM CDT MAIN FORECAST CONCERNS WILL BE THREAT OF THUNDERSTORMS NEXT FEW DAYS. FAIRLY STRONG MESOSCALE CONVECTIVE VORT MOVING THROUGH CHICAGO AREA ATTM. EARLIER CONVECTION WITH THIS SYSTEM HAS LEFT A LOT OF LOW STRATUS WHICH HAS SEVERELY LIMITED INSOLATION AND DESTABILIZATION OVER NORTHERN IL. BEST LOW LEVEL INFLOW AND INSTABILITY IS WELL SOUTHEAST ACROSS PARTS OF N AND CENTRAL IN BACK INTO CENTRAL IL. COULD BE A FEW LINGERING SHOWERS OVER FAR SE SECTIONS OF FORECAST AREA EARLY THIS EVENING...OTHERWISE DRY MUCH OF THE AREA TONIGHT. NAM INDICATES ANOTHER MCS DEVELOPING OVER IA AND MOVING INTO N AND CENTRAL IL LATE TONIGHT OR THU MORNING. SATELLITE SHOWS ANOTHER CONVECTIVELY INDUCED VORT MOVING INTO NW IA ATTM...SO NAM SEEMS REASONABLE. LOW LEVEL JET SHOULD REFOCUS FROM NORTHERN KS INTO NORTHERN MO LATE TONIGHT TO SUPPORT THIS CONVECTION. MCS MAY BE DIMINISHING DIURNALLY AS IT GET INTO IL THU MORNING. WILL KEEP CHANCE POPS GOING FOR OVERNIGHT BUT CUT BACK TO 30-40 PERCENT...WITH HIGHEST POPS IN S AND W PART OF FORECAST AREA. BEYOND THU MORNING THINGS BECOME MURKY. PATTERN CONTINUES THU...THU NIGHT...AND FRI WITH VERY WARM TROPICAL AIR MASS IN PLACE. DEWPOINTS WILL BE AROUND 70 SO THIS IS SOME OF THE JUCIEST AIR OF THE SEASON. UPPER JET CONTINUES ACROSS THE NORTHERN TIER OF STATES INTO THE GREAT LAKES...SO SHEAR IS NOT VERY STRONG OVER THIS AREA...BUT INSTABILITY SUFFICIENT FOR STRONG TO SEVERE STORMS AND THE POTENTIAL FOR HAIL AND DAMAGING WINDS. PRECIPITABLE WATER VALUES OF 1.5 TO 2 INCHES. POTENTIAL EXISTS FOR SLOW MOVING AND/OR TRAINING STORMS. THUS THE POTENTIAL FOR HEAVY RAIN AND FLOODING EXISTS. THE QUESTION IS WHERE MCS BOUNDARIES AND SMALL SCALE SHORT WAVES WILL BE WHICH WILL AFFECT PLACEMENT AND TIMING OF THUNDERSTORM CLUSTERS THU THROUGH FRI..BUT WILL CONTINUE FAIRLY HIGH CHANCE OR LIKELY CATEGORY POPS THROUGH THIS PERIOD. VIGOROUS SHORT WAVE WILL MOVE ACROSS US/CAN BORDER AND WILL EVENTUALLY FORM CUT OFF LOW OVER GREAT LAKES BY THE END OF THE WEEK. THIS WILL PUSH A COLD FRONT THROUGH THE AREA FRIDAY NIGHT...BRINGING AN END TO THE SEVERE AND HEAVY RAIN THREAT. AS UPPER LOW WOBBLES SEWD ACROSS THE GREAT LAKES PERIODS OF SHOWERY WEATHER ARE POSSIBLE THROUGH THE WEEKEND. THIS WILL BE FOLLOWED BY A DRY AND MILD PERIOD THROUGH MID WEEK. ALLSOPP && .AVIATION... 658 PM CDT FOR 00Z TAFS...FEW CHANGES FROM 18Z FORECAST THINKING WITH CONVECTIVE TRENDS/PROBABILITIES MAIN QUESTION NEXT 24 HOURS. SHORT WAVE/MCV CLEARLY EVIDENT IN VAPOR IMAGERY MOVING OFF TO THE EAST OF THE FORECAST AREA EARLY THIS EVENING...WITH SUBSIDENCE ACROSS FORECAST AREA IN WAKE OF THIS FEATURE. LOOKING AT A FEW ACARS ASCENT/DECENT SOUNDINGS FROM KORD APPEARS TO BE A WARM BULGE AROUND 800 HPA CAPPING OTHERWISE WARM/MOIST BOUNDARY LAYER...DESPITE VIS SATELLITE EVIDENCE OF LINGERING BOUNDARIES FROM MORNING/EARLY AFTERNOON MCS REMNANTS. FARTHER TO THE WEST...CONVECTION DEVELOPING ACROSS PORTIONS OF CENTRAL IOWA AHEAD OF ANOTHER WEAK MID LEVEL SHORT WAVE AND ALONG/AHEAD OF SURFACE FRONTAL BOUNDARY ACROSS WESTERN PART OF THE HAWKEYE STATE. SPC RUC MESOANALYSIS DATA INDICATES IMPRESSIVE INSTABILITY ACROSS CENTRAL/SOUTHERN IA AT THIS HOUR...WITH 4000-5000 J/KG OF MLCAPE SOUTH OF I/80 CORRIDOR. PROFILER WINDS SHOW STRONGER LOW LEVEL SOUTHERLY FLOW FARTHER WEST INTO SOUTHWEST IOWA/NEBRASKA...WITH MUCH WEAKER LOW LEVEL SUPPORT FARTHER NORTH/EAST. THUS EXPECT CONTINUED DEVELOPMENT FROM AROUND KDSM SOUTHWEST/WEST TOWARD KOMA VCNTY...WHILE AREA OF LIKELY MORE ELEVATED CONVECTION OVER NORTHERN IA EXPECTED TO WEAKEN. BEST LOW LEVEL JET/FORCING EXPECTED TO REMAIN ACROSS NEB/SDAK/WESTERN IA WITH MCS PROPAGATION OFF TO THE SOUTHEAST WHICH SHOULD KEEP THIS MAIN AREA OF CONVECTION SOUTHWEST OF TERMINALS OVERNIGHT. HOWEVER...DESPITE WEAK SUPPORT FARTHER NORTH...NAM/GFS BOTH INDICATE ELEVATED INSTABILITY OVERNIGHT WHICH MAY STILL ALLOW SOME WEAK CONVECTION/REMAINS OF NORTHERN IA ACTIVITY TO ENCROACH ON FORECAST AREA LATE TONIGHT. WILL CONTINUE TO MONITOR CONVECTIVE TRENDS TO OUR WEST THIS EVENING...THOUGH WITH LOW CONFIDENCE WILL MAINTAIN CURRENT VCSH MENTION AFTER ABOUT 09Z. MODELS MAINTAIN IDEA OF ANOTHER WEAK SHORT WAVE APPROACHING THE FORECAST AREA FROM THE WEST THURSDAY AFTERNOON...WITH COLD FRONT SAGGING ACROSS IL/WI BORDER REGION DURING AFTERNOON. WHILE UPPER FORCING APPEARS TO REMAIN FAIRLY WEAK...FORECAST SOUNDINGS DEPICT FAIRLY IMPRESSIVE INSTABILITY...WITH MLCAPE VALUES 2000-3500 J/KG ACROSS FORECAST AREA BY AFTERNOON. GFS/NGM INDICATE COMBINATION FRONT/LAKE BREEZE MAY SAG ACROSS CHI AREA LATE AFTERNOON WHICH MAY BECOME FOCUS FOR CONVECTIVE DEVELOPMENT...THOUGH NAM KEEPS FRONT OFF TO THE NORTH THROUGH 00Z FRI. CONFIDENCE REMAINS FAIRLY LOW AT THIS TIME...THOUGH HAVE GONE AHEAD AND ADDED PROB30 FOR TSRA THURSDAY AFTERNOON BASED ON MAGNITUDE OF INSTABILITY/VERY WEAK CAP. AS FOR WINDS...WEST/SOUTHWEST WINDS EARLY THIS EVENING SHOULD LOSE GUSTINESS AND BACK SLIGHTLY MORE SOUTHWEST OVERNIGHT AS BOUNDARY LAYER DECOUPLES. WEST/SOUTHWEST LOW LEVEL FLOW CONTINUES THURSDAY...PERHAPS BACKING MORE SOUTHWEST IN THE AFTERNOON IN RESPONSE TO LOW PRESSURE DEVELOPING TO OUR WEST OVER PLAINS. SOME QUESTION REMAINS ABOUT LOCATION OF WEAK COLD/STATIONARY FRONT WHICH SETTLES NEARBY BY LATE AFTERNOON...AND POTENTIAL FOR IT TO COMBINE WITH LAKE BREEZE BOUNDARY LATE IN THE DAY. THIS COULD RESULT IN EASTERLY COMPONENT TO SURFACE WIND DEVELOPING FOR KORD/KMDW...THOUGH CONFIDENCE FAIRLY LOW AT THIS TIME. RATZER && .MARINE... 200 PM...OVERALL FEW CHANGES FROM PREVIOUS FORECAST. LARGE HIGH PRESSURE WILL MOVE OFF THE SOUTHEAST U.S. COAST TONIGHT AND THURSDAY MORNING. LOW PRESSURE OVER NORTHERN MN WILL MOVE NORTHEAST ACROSS THE UPPER LAKES TONIGHT THEN ACROSS SOUTHERN QUEBEC THURSDAY. A WEAK RIDGE OF HIGH PRESSURE WILL MOVE ACROSS THE LAKES THURSDAY AFTERNOON/EVENING. WINDS WILL BECOME LIGHT AND VRB ACROSS THE LAKE DURING THIS TIME BUT A LARGE TROUGH OF LOW PRESSURE WILL DEVELOP ACROSS THE PLAINS THURSDAY AND THURSDAY NIGHT. THIS TROUGH WILL EVOLVE INTO A LARGE AREA OF LOW PRESSURE WHICH WILL SLOWLY MOVE EAST ACROSS THE NORTHERN LAKES FRIDAY AND SATURDAY. THIS LOW THEN BROADENS AND WEAKENS AS IT REMAINS OVER THE EASTERN LAKES SUNDAY AND MONDAY. THIS WILL LIKELY CAUSE A PROLONGED PERIOD OF WEST/NORTHWEST FLOW OVER THE WESTERN LAKES THROUGH MONDAY...THOUGH SPEEDS DON/T APPEAR TO BE TOO STRONG AT THIS POINT. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 658 PM CDT WED JUN 25 2008 .DISCUSSION... 247 PM CDT MAIN FORECAST CONCERNS WILL BE THREAT OF THUNDERSTORMS NEXT FEW DAYS. FAIRLY STRONG MESOSCALE CONVECTIVE VORT MOVING THROUGH CHICAGO AREA ATTM. EARLIER CONVECTION WITH THIS SYSTEM HAS LEFT A LOT OF LOW STRATUS WHICH HAS SEVERELY LIMITED INSOLATION AND DESTABILIZATION OVER NORTHERN IL. BEST LOW LEVEL INFLOW AND INSTABILITY IS WELL SOUTHEAST ACROSS PARTS OF N AND CENTRAL IN BACK INTO CENTRAL IL. COULD BE A FEW LINGERING SHOWERS OVER FAR SE SECTIONS OF FORECAST AREA EARLY THIS EVENING...OTHERWISE DRY MUCH OF THE AREA TONIGHT. NAM INDICATES ANOTHER MCS DEVELOPING OVER IA AND MOVING INTO N AND CENTRAL IL LATE TONIGHT OR THU MORNING. SATELLITE SHOWS ANOTHER CONVECTIVELY INDUCED VORT MOVING INTO NW IA ATTM...SO NAM SEEMS REASONABLE. LOW LEVEL JET SHOULD REFOCUS FROM NORTHERN KS INTO NORTHERN MO LATE TONIGHT TO SUPPORT THIS CONVECTION. MCS MAY BE DIMINISHING DIURNALLY AS IT GET INTO IL THU MORNING. WILL KEEP CHANCE POPS GOING FOR OVERNIGHT BUT CUT BACK TO 30-40 PERCENT...WITH HIGHEST POPS IN S AND W PART OF FORECAST AREA. BEYOND THU MORNING THINGS BECOME MURKY. PATTERN CONTINUES THU...THU NIGHT...AND FRI WITH VERY WARM TROPICAL AIR MASS IN PLACE. DEWPOINTS WILL BE AROUND 70 SO THIS IS SOME OF THE JUCIEST AIR OF THE SEASON. UPPER JET CONTINUES ACROSS THE NORTHERN TIER OF STATES INTO THE GREAT LAKES...SO SHEAR IS NOT VERY STRONG OVER THIS AREA...BUT INSTABILITY SUFFICIENT FOR STRONG TO SEVERE STORMS AND THE POTENTIAL FOR HAIL AND DAMAGING WINDS. PRECIPITABLE WATER VALUES OF 1.5 TO 2 INCHES. POTENTIAL EXISTS FOR SLOW MOVING AND/OR TRAINING STORMS. THUS THE POTENTIAL FOR HEAVY RAIN AND FLOODING EXISTS. THE QUESTION IS WHERE MCS BOUNDARIES AND SMALL SCALE SHORT WAVES WILL BE WHICH WILL AFFECT PLACEMENT AND TIMING OF THUNDERSTORM CLUSTERS THU THROUGH FRI..BUT WILL CONTINUE FAIRLY HIGH CHANCE OR LIKELY CATEGORY POPS THROUGH THIS PERIOD. VIGOROUS SHORT WAVE WILL MOVE ACROSS US/CAN BORDER AND WILL EVENTUALLY FORM CUT OFF LOW OVER GREAT LAKES BY THE END OF THE WEEK. THIS WILL PUSH A COLD FRONT THROUGH THE AREA FRIDAY NIGHT...BRINGING AN END TO THE SEVERE AND HEAVY RAIN THREAT. AS UPPER LOW WOBBLES SEWD ACROSS THE GREAT LAKES PERIODS OF SHOWERY WEATHER ARE POSSIBLE THROUGH THE WEEKEND. THIS WILL BE FOLLOWED BY A DRY AND MILD PERIOD THROUGH MID WEEK. ALLSOPP && .AVIATION... 658 PM CDT FOR 00Z TAFS...FEW CHANGES FROM 18Z FORECAST THINKING WITH CONVECTIVE TRENDS/PROBABILITIES MAIN QUESTION NEXT 24 HOURS. SHORT WAVE/MCV CLEARLY EVIDENT IN VAPOR IMAGERY MOVING OFF TO THE EAST OF THE FORECAST AREA EARLY THIS EVENING...WITH SUBSIDENCE ACROSS FORECAST AREA IN WAKE OF THIS FEATURE. LOOKING AT A FEW ACARS ASCENT/DECENT SOUNDINGS FROM KORD APPEARS TO BE A WARM BULGE AROUND 800 HPA CAPPING OTHERWISE WARM/MOIST BOUNDARY LAYER...DESPITE VIS SATELLITE EVIDENCE OF LINGERING BOUNDARIES FROM MORNING/EARLY AFTERNOON MCS REMNANTS. FARTHER TO THE WEST...CONVECTION DEVELOPING ACROSS PORTIONS OF CENTRAL IOWA AHEAD OF ANOTHER WEAK MID LEVEL SHORT WAVE AND ALONG/AHEAD OF SURFACE FRONTAL BOUNDARY ACROSS WESTERN PART OF THE HAWKEYE STATE. SPC RUC MESOANALYSIS DATA INDICATES IMPRESSIVE INSTABILITY ACROSS CENTRAL/SOUTHERN IA AT THIS HOUR...WITH 4000-5000 J/KG OF MLCAPE SOUTH OF I/80 CORRIDOR. PROFILER WINDS SHOW STRONGER LOW LEVEL SOUTHERLY FLOW FARTHER WEST INTO SOUTHWEST IOWA/NEBRASKA...WITH MUCH WEAKER LOW LEVEL SUPPORT FARTHER NORTH/EAST. THUS EXPECT CONTINUED DEVELOPMENT FROM AROUND KDSM SOUTHWEST/WEST TOWARD KOMA VCNTY...WHILE AREA OF LIKELY MORE ELEVATED CONVECTION OVER NORTHERN IA EXPECTED TO WEAKEN. BEST LOW LEVEL JET/FORCING EXPECTED TO REMAIN ACROSS NEB/SDAK/WESTERN IA WITH MCS PROPAGATION OFF TO THE SOUTHEAST WHICH SHOULD KEEP THIS MAIN AREA OF CONVECTION SOUTHWEST OF TERMINALS OVERNIGHT. HOWEVER...DESPITE WEAK SUPPORT FARTHER NORTH...NAM/GFS BOTH INDICATE ELEVATED INSTABILITY OVERNIGHT WHICH MAY STILL ALLOW SOME WEAK CONVECTION/REMAINS OF NORTHERN IA ACTIVITY TO ENCROACH ON FORECAST AREA LATE TONIGHT. WILL CONTINUE TO MONITOR CONVECTIVE TRENDS TO OUR WEST THIS EVENING...THOUGH WITH LOW CONFIDENCE WILL MAINTAIN CURRENT VCSH MENTION AFTER ABOUT 09Z. MODELS MAINTAIN IDEA OF ANOTHER WEAK SHORT WAVE APPROACHING THE FORECAST AREA FROM THE WEST THURSDAY AFTERNOON...WITH COLD FRONT SAGGING ACROSS IL/WI BORDER REGION DURING AFTERNOON. WHILE UPPER FORCING APPEARS TO REMAIN FAIRLY WEAK...FORECAST SOUNDINGS DEPICT FAIRLY IMPRESSIVE INSTABILITY...WITH MLCAPE VALUES 2000-3500 J/KG ACROSS FORECAST AREA BY AFTERNOON. GFS/NGM INDICATE COMBINATION FRONT/LAKE BREEZE MAY SAG ACROSS CHI AREA LATE AFTERNOON WHICH MAY BECOME FOCUS FOR CONVECTIVE DEVELOPMENT...THOUGH NAM KEEPS FRONT OFF TO THE NORTH THROUGH 00Z FRI. CONFIDENCE REMAINS FAIRLY LOW AT THIS TIME...THOUGH HAVE GONE AHEAD AND ADDED PROB30 FOR TSRA THURSDAY AFTERNOON BASED ON MAGNITUDE OF INSTABILITY/VERY WEAK CAP. AS FOR WINDS...WEST/SOUTHWEST WINDS EARLY THIS EVENING SHOULD LOSE GUSTINESS AND BACK SLIGHTLY MORE SOUTHWEST OVERNIGHT AS BOUNDARY LAYER DECOUPLES. WEST/SOUTHWEST LOW LEVEL FLOW CONTINUES THURSDAY...PERHAPS BACKING MORE SOUTHWEST IN THE AFTERNOON IN RESPONSE TO LOW PRESSURE DEVELOPING TO OUR WEST OVER PLAINS. SOME QUESTION REMAINS ABOUT LOCATION OF WEAK COLD/STATIONARY FRONT WHICH SETTLES NEARBY BY LATE AFTERNOON...AND POTENTIAL FOR IT TO COMBINE WITH LAKE BREEZE BOUNDARY LATE IN THE DAY. THIS COULD RESULT IN EASTERLY COMPONENT TO SURFACE WIND DEVELOPING FOR KORD/KMDW...THOUGH CONFIDENCE FAIRLY LOW AT THIS TIME. RATZER && .MARINE... 200 PM...OVERALL FEW CHANGES FROM PREVIOUS FORECAST. LARGE HIGH PRESSURE WILL MOVE OFF THE SOUTHEAST U.S. COAST TONIGHT AND THURSDAY MORNING. LOW PRESSURE OVER NORTHERN MN WILL MOVE NORTHEAST ACROSS THE UPPER LAKES TONIGHT THEN ACROSS SOUTHERN QUEBEC THURSDAY. A WEAK RIDGE OF HIGH PRESSURE WILL MOVE ACROSS THE LAKES THURSDAY AFTERNOON/EVENING. WINDS WILL BECOME LIGHT AND VRB ACROSS THE LAKE DURING THIS TIME BUT A LARGE TROUGH OF LOW PRESSURE WILL DEVELOP ACROSS THE PLAINS THURSDAY AND THURSDAY NIGHT. THIS TROUGH WILL EVOLVE INTO A LARGE AREA OF LOW PRESSURE WHICH WILL SLOWLY MOVE EAST ACROSS THE NORTHERN LAKES FRIDAY AND SATURDAY. THIS LOW THEN BROADENS AND WEAKENS AS IT REMAINS OVER THE EASTERN LAKES SUNDAY AND MONDAY. THIS WILL LIKELY CAUSE A PROLONGED PERIOD OF WEST/NORTHWEST FLOW OVER THE WESTERN LAKES THROUGH MONDAY...THOUGH SPEEDS DON/T APPEAR TO BE TOO STRONG AT THIS POINT. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1254 PM CDT TUE JUN 24 2008 .DISCUSSION... ISSUED 955 AM CDT TUE JUN 24 2008 HIGH PRESSURE RIDGE AXIS JUST OFF TO THE EAST... WITH THE REMAINS OF A THUNDERSTORM COMPLEX MOVING INTO EAST CENTRAL MO THIS MORNING. MOST INTENSE THUNDERSTORMS DIVING SWD. MOST INTENSE INSTABILITY STILL OFF TO THE SW...UP THROUGH THE STATE OF MISSOURI AND BACK INTO THE PLAINS. RUC MODEL HAS A HANDLE ON WHERE THE ACTIVITY IS THIS MORNING...AND PRETTY MUCH STALLS IT OUT IN THE NEXT COUPLE OF HOURS ALONG AND WEST OF THE MISS RIVER VALLEY. NOT READY TO UP THE POPS JUST YET. WILL MONITOR FOR ADVANCEMENT OF THE FRONT EDGE... KEEPING FORECAST AND UPDATING FOR MORNING WORDING. && .AVIATION... ISSUED 1250 PM CDT TUE JUN 24 2008 TROUBLESOME TAFS THIS TIME AROUND. IN THE SHORT TERM...HAVE ADDED TSRA IN THE TAFS FOR SPI AND DEC. KEEPING VCTS ELSEWHERE AS THE ACTIVITY IS MOVING INTO A RELATIVELY STABLE AIRMASS. FOR THE LONGER TERM...MODELS HAVE SCATTERED THUNDER ALL NIGHT. HAVE KEYED IN ON THE MOST LIKELY TIMES AFTER MIDNIGHT AND PUSHED THE THUNDERSTORMS THROUGH BY EARLY MORNING. ENDING THE PRECIP BY 13Z MAY ACTUALLY BE A BIT OPTIMISTIC...BUT HAVE MAINTAINED VCTS AFTER 13Z IN LIEU OF INHIBITING ANY ONE PARTICULAR TERMINAL. HJS && .PREV DISCUSSION... ISSUED 325 AM CDT TUE JUN 24 2008 FORECAST CONCERN IS CONVECTION CHANCES THROUGH SAT AS SERIES OF SHORT WAVES RIDE EASTWARD ACROSS THE MIDWEST OVER TOP OF UPPER LEVEL RIDGE ACROSS THE SOUTHERN STATES. 00Z SHORT RANGE MODELS ARE IN MUCH BETTER AGREEMENT THAN 24 HOURS AGO AND USED A BLEND. GUIDANCE TEMPS SIMILAR THROUGH THU AND USED A BLEND HERE TOO. SHORT TERM...TODAY THROUGH THURSDAY. 08Z/3 AM SURFACE MAP SHOWS 1021 MB HIGH PRESSURE CENTERED OVER GARY INDIANA AND PROVIDING FAIR SKIES AND LIGHT TO CALM WINDS OVER CENTRAL/SE IL EARLY THIS MORNING. SOME MID/HIGH CLOUDS WERE SPREADING EASTWARD INTO CENTRAL IL. LARGE MCS WAS OVER CENTRAL AND SOUTHERN NEBRASKA INTO NE KS WHILE ISOLATED SHOWERS FROM CENTRAL IA INTO NE MO AN FAR NW IL AND DRIFTING ESE. TEMPS WERE IN THE UPPER 50S AND LOWER 60S WHILE DEWPOINTS IN THE LOW TO MID 50S. ALOFT THE UPPER LEVEL TROF WAS OVER QUEBEC AND THE APPALACHIANS WHILE UPPER LEVEL RIDGE FROM TX/LA WESTWARD ACROSS NORTHERN MEXICO. SHORT WAVES WERE OVER THE CENTRAL AND NORTHERN PLAINS WITH CLOSEST ONE TO IL OVER CENTRAL IA. MODELS TRENDING DRIER TODAY OVER CENTRAL/SE IL AS HIGH PRESSURE DRIFTS EASTWARD OVER OH AND EASTERN KY BY SUNSET WITH SOME UPPER LEVEL RIDGING INTO IL. KEPT JUST 20 TO 30% CHANCE OF SHOWERS AND THUNDERSTORMS WEST OF A BLOOMINGTON TO EFFINGHAM LINE TODAY FROM WEAK WARM AIR ADVECTION IN WESTERN IL AS SKIES BECOME PARTLY SUNNY. EASTERN IL SHOULD STAY DRY TODAY WITH MORE SUNSHINE DUE TO CLOSER INFLUENCE OF HIGH PRESSURE/STRONGER SUBSIDENCE. WARMER HIGHS IN THE LOW TO MID 80S WITH 850 MB TEMPS WARMING NEARLY 2C TO 14 TO 16C. WIDELY SCATTERED CONVECTION CONTINUES TONIGHT WITH IL IN WARM AIR ADVECTION PATTERN AND WEAKER PART OF LOW LEVEL JET AS HIGH PRESSURE DRIFTS OVER THE MID ATLANTIC STATES BY SUNRISE WED. STRONG LOW LEVEL JET AND SHORT WAVE SHOULD DEVELOP A LARGE MCS OVER SW IA/NW MO WHERE SPC HAS SLIGHT RISK OF SEVERE STORMS. THIS MCS TO WEAKEN AS ITS SCATTERED CONVECTION SPREAD ACROSS CENTRAL IL LATER TONIGHT INTO WED. WARMER AND MORE HUMID WED WITH HIGHS IN THE 85 TO 90F AND DEWPOINTS IN THE 60S WITH SSW BREEZES. CONVECTION CHANCES APPEAR TO SET UP BEST OVER IA AND NORTHERN IL/IN WED NIGHT/THU WHERE FRONTAL BOUNDARY WILL BE. HAVE HIGHEST POPS IN OUR NORTHERN COUNTIES. SPC HAS SLIGHT RISK OF SEVERE STORMS NORTH OF PEORIA BUT BEST CHANCE OF SEVERE STORMS OVER IA/WI AND FAR NW IL. ANOTHER VERY WARM AND HUMID DAY THU WITH SSW WINDS. HIGHS IN THE UPPER 80S/90F AND DEWPOINTS IN THE UPPER 60S. LONG TERM...THURSDAY NIGHT THROUGH MONDAY. CONVECTION CHANCES APPEARS TO AFFECT AREAS MAINLY NORTH OF I-70 THU NIGHT/FRI WHERE SPC HAS SLIGHT RISK OF SEVERE STORMS THU AFTERNOON AND THU EVENING. BUT BEST CHANCE OF SEVERE STORMS THEN IS OVER THE DAKOTAS AND NORTHERN NEBRASKA. PER SPC DAY3 OUTLOOK... THUNDERSTORMS WILL INCREASE IN COVERAGE/INTENSITY ACROSS THE CORN BELT/OHIO VALLEY THURSDAY AFTERNOON/EARLY EVENING ALONG AND AHEAD OF A WEST-EAST ELONGATING/STALLING FRONTAL BOUNDARY. A POTENTIALLY VERY UNSTABLE/WEAKLY CAPPED AIRMASS WILL LIKELY EXIST ALONG/SOUTH OF THE FRONT...WITH THUNDERSTORM DEVELOPMENT FURTHER AIDED BY THE POSSIBILITY OF ONE OR MORE CONVECTIVELY ENHANCED VORTICITY MAXIMA. BENEATH ONLY MODEST MID LEVEL FLOW...SCATTERED MULTICELL STORMS CAPABLE OF DAMAGING WINDS/SEVERE HAIL ARE LIKELY THURSDAY AFTERNOON/EVENING. MCS ACTIVITY AGAIN FOCUSED UP NORTH OF IA/WI AND NORTHERN IL WHERE HEAVY RAIN ALSO POSSIBLE. VERY WARM AND HUMID AGAIN FRI WITH HIGHS IN THE UPPER 80S/90F AND DEWPOINTS IN THE UPPER 60S/70F WITH SSW BREEZES. GFS AND ECMWF MODELS SIMILAR IN SHOWING AN UPPER LEVEL LOW/TROF MOVING INTO THE GREAT LAKES REGION THIS WEEKEND AND DRIVING A COLD FRONT SE THROUGH IL LATER FRI NIGHT AND SAT. THIS TO PRODUCE A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS. BOTH MODELS KEEP QPF NE OF CENTRAL IL SUNDAY CLOSER TO UPPER LEVEL LOW OVER NE MI. HIGHS IN THE 80S THIS WEEKEND WHICH IS CLOSE TO NORMAL FOR LATE JUNE. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 154 PM EDT WED JUN 25 2008 .UPDATE/AVIATION... GRIDS/ZONES...WILL LET SCT POPS RIDE FOR THE TIME BEING FOR THE AFTERNOON. AREA OF SHOWERS IS WORKING EAST WHICH WILL AFFECT MAINLY SOUTHERN PORTIONS OF THE FORECAST AREA. BIG QUESTIONS REMAINS IF THE ATMOSPHERE CAN RECOVER SUFFICIENTLY AND FAST ENOUGH TO ALLOW FOR ADDITIONAL STORMS TO DEVELOP IN ASSOCIATION WITH THE APPROACHING MCV. IR SAT SHOWING GENERALLY WARMING CLOUD TOPS AND NO REAL SIGNS OF ANYTHING TO KEY IN ON. POCKETS OF CLEARING JUST HEAD OF THE MCV HAVE ALLOWED A FEW AREAS TO CLIMB BACK TOWARDS 80. WILL CONTINUE TO MONITOR TRENDS BUT NO FURTHER UPDATES ANTICIPATED ATTM PRIOR TO AFTERNOON PACKAGE ISSUANCE. AVIATION WISE...FIRST BATCH OF PRECIP HAS CLEARED BOTH SITES LEAVING BEHIND VFR CONDITIONS AGAIN. HAVE WENT RATHER CONSERVATIVE AT BOTH SITES THROUGH 00Z WITH MORE OF A VCSH MENTION. PROXIMITY OF INITIAL PRECIP TO KSBN DID APPEAR TO WARRANT A BRIEF TEMPO GROUP. TONIGHT MORE THAN LIKELY WILL BE DRY FOR MUCH OF THE AREA UNTIL TOWARDS MORNING WITH NEXT MCS MOVING IN. WILL KEEP HIGH AND DRY FOR NOW. && PREV DISCUSSION... /ISSUED 416 AM EDT WED JUN 25 2008/ SHORT TERM... TODAY THROUGH THURSDAY NIGHT VERY COMPLICATED FORECAST IN STORE FOR THE PERIOD. CONCERNS ON CLOUD COVER/CONVECTIVE INFLUENCES/AND STRENGTH OF MID LEVEL COOLING ARE ABOUND. CONVECTIVE COMPLEX OVER MO/IL IS BEING SUPPORTED BY A MID LEVEL IMPULSE AND ASSOCIATED LLJ. THIS IMPULSE IS SLOWLY PUSHING EAST TOWARD THE FA. LARGE SCALE ASCENT AND INCREASED LL FLOW PER PROFILER DATA...UNDER STEEPENING MID LEVEL LAPSE RATES IS SUPPORTING SCT SHRA/TS DEVELOPMENT OVER NE IL. EXPECTING THIS AREA OF SHOWERS AND THUNDERSTORMS TO CONTINUE INTO THE FA THROUGH MORNING. TODAY...HAVE UTILIZED THE NGM FOR SYNOPTIC STRUCTURE AS THE GFS/NAM/RUC ALL SUFFER GREATLY FROM CONVECTIVE FEEDBACK AND OTHER BIAS ISSUES. EXPECTING THE MID LEVEL IMPULSE DEPICTED ON WATER VAPOR OVER SOUTHERN IA TO SLOWLY PUSH EAST INTO THE FA. ROBUST CONVECTION/LATENT HEAT RELEASE UPSTREAM WILL FURTHER ENHANCE LL PV FIELDS AND HELP IN THE MAINTENANCE AND PROPAGATION OF THIS IMPULSE OVER THE REGION TODAY. GROWING INSTABILITY PER MID LEVEL COOLING AND ADDED LL MOISTURE WILL SUPPORT CONVECTION THROUGH MOST OF THE DAY...TRANSITIONING EAST THROUGH THE DAY. CLOUD COVER IS EXPECTED TO HIGHLY LIMIT SOLAR INSOLATION OVER NW THIRD OF THE FA...THUS LIMITING INSTABILITY. BEST CHANCE FOR STRONG/SEVERE STORMS WILL BE EAST IF ENOUGH SUN IS REALIZED...WHICH WOULD SUPPORT NEARLY 2000 J/KG CAPE AND PULSE WIND/HAIL THREAT. HOWEVER...CONVECTIVE OUTFLOW AND CLOUD COVER MAY HIGHLY LIMIT TEMPS AND FEEL SEVERE WORDING IS NOT PRUDENT ATTM. TEMPS IN THE GRIDS ARE LIKELY STILL TOO WARM. HAVE LOWERED SOME ALREADY...AND THINGS MAY NEED TO BE LOWERED MORE. IT IS ENTIRELY POSSIBLE THAT A MAJORITY OF THE FA MAY NOT SURPASS THE LOW TO MID 70S. LEAD SW WILL EXIT THE REGION TONIGHT. CONVECTIVE OUTFLOW MODIFIED FRONTAL BOUNDARY OVER IA/MN IS EXPECTED TO BE THE INITIATION POINT OF NEW VIGOROUS CONVECTION THIS AFTERNOON/EVENING. HAVE RETAINED POP MENTION FOR A POSSIBLE MCS PROPAGATING INTO THE FA TONIGHT. THETA-E RIDGING PER 305 K MIXING RATIO PROGS WOULD SUPPORT PROPAGATION OF THIS SYSTEM INTO THE REGION...WITH THE BEST CHANCE FOR TS RESIDING IN NW. THUR...FLATTENING ACTIVE NW FLOW WILL SEND ANOTHER MID LEVEL DISTURBANCE INTO THE REGION ALONG A STALLED FRONTAL BOUNDARY TO THE NORTH. THIS FITS THE MCS/DERECHO PATTERN WELL FOR THE AREA...ESPECIALLY WITH LL MOISTURE AND HEAT IN PLACE. HAVE RETAINED 50 POP MENTION IN THE NORTH...TRENDING TO 30 SOUTH WHERE MID LEVEL WARMING/CAPPING MAY LIMIT CONVECTIVE POTENTIAL. OTHERWISE...HAVE RAISED HIGHS A FEW DEGREES GIVEN SOUTHERLY/DEEP MIXED FLOW. H85 TEMPS AROUND 17C WOULD SPELL MID 80S EASILY FOR MOST OF THE FA. LONG TERM... BRIEF RESPITE TO PNA PATTN ACRS NOAM WILL BREAK TWD SIG AMPLIFICATION ONCE AGAIN BY NXT WEEKEND IN RESPONSE TO SERIES OF FAST MOVING EMBEDDED SW/S WITHIN SEASONABLY STRONG WESTERLY FLW AND DEEP GULF OF AK STORM MOVING INTO WRN CANADA. DIFFICULT TO TIME SW TROUGHS AS SEEN W/INCONSISTENT MODEL SOLUTIONS...ESP OP GFS AND LARGELY IGNORED IN FVR OF ECMWF WHICH RETAINED THE GREATEST PREV RUN CONTINUITY. MAIN STORY WILL BE THE DVLPMNT OF YET ANOTHER DEEP COLD CORE CUTOFF LOW ACRS THE GREAT LAKES BY WEEKS END W/LIKELY DAILY DIURNALLY DRIVEN CONVN FRI-MON BFR SYS OPENS AND FILLS. WILL STAY CLOSE TO PRIOR THINKING W/FEW TWEAKS TO POPS ACCOUNTING FOR PREFERRED DIURNAL CYCLE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...HOLSTEN AVIATION...FISHER UPDATE...STEINWEDEL/FISHER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 728 AM EDT WED JUN 25 2008 .UPDATE/AVIATION... ZONE/GRID UPDATE FORTHCOMING TO INCREASE POPS NORTHWEST HALF TO 2/3RD TO CATEGORICAL FOR THIS MORNING FOR APPROACHING MCS. IR CLOUD TOPS AND WATER VAPOR LOOP INDICATE THE COMPLEX IS LIKELY UNDERGOING A SLOW DECAYING PROCESS. HOWEVER...COMBINATION OF 30 TO 40 KT LLJ STILL FEEDING IN...OBVIOUS MCV SHOWING UP ON RADAR AND SATELLITE DATA...ALL SUGGEST THAT COMPLEX SHOULD BRING SOME RAINFALL TO AT LEAST THE NOTED AREAS FOR PART OF THIS MORNING. WILL KEEP SE AREAS IN THE SCT WORDING FOR NOW WITH BULK OF ACTIVITY REMAINING NORTH AT THIS TIME. WILL CONTINUE TO MONITOR TRENDS ON COMPLEX AND UPDATE MORE IF NEEDED. THERE ARE SOME CLUSTERS OF STORMS EMBEDDED YET WHICH WILL PRODUCE LOCALLY HEAVY RAINFALL ON THE ORDER OF AN INCH OR MORE PER HOUR. AVIATION WISE...UPSTREAM OBS SHOW GENERALLY VFR CONDITIONS IN TERMS OF CIGS/VSBYS IN MOST OF THE AREA OF PRECIP. AREAS THAT EXPERIENCE STORMS ARE SEEING BRIEF DROPS TO MVFR CIGS. FOR NOW AT KSBN HAVE WENT PREDOMINANT VFR WITH A TEMPO BETWEEN 13 AND 15Z BKN025 TO COVER ANY CONVECTION. AT KFWA HAVE KEPT VCSH FOR NOW AND SEE HOW THE AREA PROGRESSES OVER THE NEXT HOUR OR 2. BEYOND 16Z NO CHANGES AS REMAINDER OF MESOSCALE SETUP REMAINS TOO QUESTIONABLE AT THIS POINT. && .PREV DISCUSSION... /ISSUED 416 AM EDT WED JUN 25 2008/ SHORT TERM... TODAY THROUGH THURSDAY NIGHT VERY COMPLICATED FORECAST IN STORE FOR THE PERIOD. CONCERNS ON CLOUD COVER/CONVECTIVE INFLUENCES/AND STRENGTH OF MID LEVEL COOLING ARE ABOUND. CONVECTIVE COMPLEX OVER MO/IL IS BEING SUPPORTED BY A MID LEVEL IMPULSE AND ASSOCIATED LLJ. THIS IMPULSE IS SLOWLY PUSHING EAST TOWARD THE FA. LARGE SCALE ASCENT AND INCREASED LL FLOW PER PROFILER DATA...UNDER STEEPENING MID LEVEL LAPSE RATES IS SUPPORTING SCT SHRA/TS DEVELOPMENT OVER NE IL. EXPECTING THIS AREA OF SHOWERS AND THUNDERSTORMS TO CONTINUE INTO THE FA THROUGH MORNING. TODAY...HAVE UTILIZED THE NGM FOR SYNOPTIC STRUCTURE AS THE GFS/NAM/RUC ALL SUFFER GREATLY FROM CONVECTIVE FEEDBACK AND OTHER BIAS ISSUES. EXPECTING THE MID LEVEL IMPULSE DEPICTED ON WATER VAPOR OVER SOUTHERN IA TO SLOWLY PUSH EAST INTO THE FA. ROBUST CONVECTION/LATENT HEAT RELEASE UPSTREAM WILL FURTHER ENHANCE LL PV FIELDS AND HELP IN THE MAINTENANCE AND PROPAGATION OF THIS IMPULSE OVER THE REGION TODAY. GROWING INSTABILITY PER MID LEVEL COOLING AND ADDED LL MOISTURE WILL SUPPORT CONVECTION THROUGH MOST OF THE DAY...TRANSITIONING EAST THROUGH THE DAY. CLOUD COVER IS EXPECTED TO HIGHLY LIMIT SOLAR INSOLATION OVER NW THIRD OF THE FA...THUS LIMITING INSTABILITY. BEST CHANCE FOR STRONG/SEVERE STORMS WILL BE EAST IF ENOUGH SUN IS REALIZED...WHICH WOULD SUPPORT NEARLY 2000 J/KG CAPE AND PULSE WIND/HAIL THREAT. HOWEVER...CONVECTIVE OUTFLOW AND CLOUD COVER MAY HIGHLY LIMIT TEMPS AND FEEL SEVERE WORDING IS NOT PRUDENT ATTM. TEMPS IN THE GRIDS ARE LIKELY STILL TOO WARM. HAVE LOWERED SOME ALREADY...AND THINGS MAY NEED TO BE LOWERED MORE. IT IS ENTIRELY POSSIBLE THAT A MAJORITY OF THE FA MAY NOT SURPASS THE LOW TO MID 70S. LEAD SW WILL EXIT THE REGION TONIGHT. CONVECTIVE OUTFLOW MODIFIED FRONTAL BOUNDARY OVER IA/MN IS EXPECTED TO BE THE INITIATION POINT OF NEW VIGOROUS CONVECTION THIS AFTERNOON/EVENING. HAVE RETAINED POP MENTION FOR A POSSIBLE MCS PROPAGATING INTO THE FA TONIGHT. THETA-E RIDGING PER 305 K MIXING RATIO PROGS WOULD SUPPORT PROPAGATION OF THIS SYSTEM INTO THE REGION...WITH THE BEST CHANCE FOR TS RESIDING IN NW. THUR...FLATTENING ACTIVE NW FLOW WILL SEND ANOTHER MID LEVEL DISTURBANCE INTO THE REGION ALONG A STALLED FRONTAL BOUNDARY TO THE NORTH. THIS FITS THE MCS/DERECHO PATTERN WELL FOR THE AREA...ESPECIALLY WITH LL MOISTURE AND HEAT IN PLACE. HAVE RETAINED 50 POP MENTION IN THE NORTH...TRENDING TO 30 SOUTH WHERE MID LEVEL WARMING/CAPPING MAY LIMIT CONVECTIVE POTENTIAL. OTHERWISE...HAVE RAISED HIGHS A FEW DEGREES GIVEN SOUTHERLY/DEEP MIXED FLOW. H85 TEMPS AROUND 17C WOULD SPELL MID 80S EASILY FOR MOST OF THE FA. LONG TERM... BRIEF RESPITE TO PNA PATTN ACRS NOAM WILL BREAK TWD SIG AMPLIFICATION ONCE AGAIN BY NXT WEEKEND IN RESPONSE TO SERIES OF FAST MOVING EMBEDDED SW/S WITHIN SEASONABLY STRONG WESTERLY FLW AND DEEP GULF OF AK STORM MOVING INTO WRN CANADA. DIFFICULT TO TIME SW TROUGHS AS SEEN W/INCONSISTENT MODEL SOLUTIONS...ESP OP GFS AND LARGELY IGNORED IN FVR OF ECMWF WHICH RETAINED THE GREATEST PREV RUN CONTINUITY. MAIN STORY WILL BE THE DVLPMNT OF YET ANOTHER DEEP COLD CORE CUTOFF LOW ACRS THE GREAT LAKES BY WEEKS END W/LIKELY DAILY DIURNALLY DRIVEN CONVN FRI-MON BFR SYS OPENS AND FILLS. WILL STAY CLOSE TO PRIOR THINKING W/FEW TWEAKS TO POPS ACCOUNTING FOR PREFERRED DIURNAL CYCLE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ AVIATION...FISHER UPDATE...STEINWEDEL SHORT TERM...CHAMBERLAIN LONG TERM...HOLSTEN in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 416 AM EDT WED JUN 25 2008 .SHORT TERM... TODAY THROUGH THURSDAY NIGHT VERY COMPLICATED FORECAST IN STORE FOR THE PERIOD. CONCERNS ON CLOUD COVER/CONVECTIVE INFLUENCES/AND STRENGTH OF MID LEVEL COOLING ARE ABOUND. CONVECTIVE COMPLEX OVER MO/IL IS BEING SUPPORTED BY A MID LEVEL IMPULSE AND ASSOCIATED LLJ. THIS IMPULSE IS SLOWLY PUSHING EAST TOWARD THE FA. LARGE SCALE ASCENT AND INCREASED LL FLOW PER PROFILER DATA...UNDER STEEPENING MID LEVEL LAPSE RATES IS SUPPORTING SCT SHRA/TS DEVELOPMENT OVER NE IL. EXPECTING THIS AREA OF SHOWERS AND THUNDERSTORMS TO CONTINUE INTO THE FA THROUGH MORNING. TODAY...HAVE UTILIZED THE NGM FOR SYNOPTIC STRUCTURE AS THE GFS/NAM/RUC ALL SUFFER GREATLY FROM CONVECTIVE FEEDBACK AND OTHER BIAS ISSUES. EXPECTING THE MID LEVEL IMPULSE DEPICTED ON WATER VAPOR OVER SOUTHERN IA TO SLOWLY PUSH EAST INTO THE FA. ROBUST CONVECTION/LATENT HEAT RELEASE UPSTREAM WILL FURTHER ENHANCE LL PV FIELDS AND HELP IN THE MAINTENANCE AND PROPAGATION OF THIS IMPULSE OVER THE REGION TODAY. GROWING INSTABILITY PER MID LEVEL COOLING AND ADDED LL MOISTURE WILL SUPPORT CONVECTION THROUGH MOST OF THE DAY...TRANSITIONING EAST THROUGH THE DAY. CLOUD COVER IS EXPECTED TO HIGHLY LIMIT SOLAR INSOLATION OVER NW THIRD OF THE FA...THUS LIMITING INSTABILITY. BEST CHANCE FOR STRONG/SEVERE STORMS WILL BE EAST IF ENOUGH SUN IS REALIZED...WHICH WOULD SUPPORT NEARLY 2000 J/KG CAPE AND PULSE WIND/HAIL THREAT. HOWEVER...CONVECTIVE OUTFLOW AND CLOUD COVER MAY HIGHLY LIMIT TEMPS AND FEEL SEVERE WORDING IS NOT PRUDENT ATTM. TEMPS IN THE GRIDS ARE LIKELY STILL TOO WARM. HAVE LOWERED SOME ALREADY...AND THINGS MAY NEED TO BE LOWERED MORE. IT IS ENTIRELY POSSIBLE THAT A MAJORITY OF THE FA MAY NOT SURPASS THE LOW TO MID 70S. LEAD SW WILL EXIT THE REGION TONIGHT. CONVECTIVE OUTFLOW MODIFIED FRONTAL BOUNDARY OVER IA/MN IS EXPECTED TO BE THE INITIATION POINT OF NEW VIGOROUS CONVECTION THIS AFTERNOON/EVENING. HAVE RETAINED POP MENTION FOR A POSSIBLE MCS PROPAGATING INTO THE FA TONIGHT. THETA-E RIDGING PER 305 K MIXING RATIO PROGS WOULD SUPPORT PROPAGATION OF THIS SYSTEM INTO THE REGION...WITH THE BEST CHANCE FOR TS RESIDING IN NW. THUR...FLATTENING ACTIVE NW FLOW WILL SEND ANOTHER MID LEVEL DISTURBANCE INTO THE REGION ALONG A STALLED FRONTAL BOUNDARY TO THE NORTH. THIS FITS THE MCS/DERECHO PATTERN WELL FOR THE AREA...ESPECIALLY WITH LL MOISTURE AND HEAT IN PLACE. HAVE RETAINED 50 POP MENTION IN THE NORTH...TRENDING TO 30 SOUTH WHERE MID LEVEL WARMING/CAPPING MAY LIMIT CONVECTIVE POTENTIAL. OTHERWISE...HAVE RAISED HIGHS A FEW DEGREES GIVEN SOUTHERLY/DEEP MIXED FLOW. H85 TEMPS AROUND 17C WOULD SPELL MID 80S EASILY FOR MOST OF THE FA. && .LONG TERM... BRIEF RESPITE TO PNA PATTN ACRS NOAM WILL BREAK TWD SIG AMPLIFICATION ONCE AGAIN BY NXT WEEKEND IN RESPONSE TO SERIES OF FAST MOVING EMBEDDED SW/S WITHIN SEASONABLY STRONG WESTERLY FLW AND DEEP GULF OF AK STORM MOVING INTO WRN CANADA. DIFFICULT TO TIME SW TROUGHS AS SEEN W/INCONSISTENT MODEL SOLUTIONS...ESP OP GFS AND LARGELY IGNORED IN FVR OF ECMWF WHICH RETAINED THE GREATEST PREV RUN CONTINUITY. MAIN STORY WILL BE THE DVLPMNT OF YET ANOTHER DEEP COLD CORE CUTOFF LOW ACRS THE GREAT LAKES BY WEEKS END W/LIKELY DAILY DIURNALLY DRIVEN CONVN FRI-MON BFR SYS OPENS AND FILLS. WILL STAY CLOSE TO PRIOR THINKING W/FEW TWEAKS TO POPS ACCOUNTING FOR PREFERRED DIURNAL CYCLE. && .AVIATION.../06Z TAFS/ AVIATION FORECAST CONCERNS INCLUDE SHRA/TS CHANCES AT SBN AND FWA. CURRENT TS COMPLEX IN MO/IL IS PUSHING NE AND IS EXPECTED TO ENTER THE FA BY 09-10Z SUPPORTED BY WAA. HAVE INCLUDED TEMPO AT SBN WHERE BEST LIFT AND INSTABILITY WILL BE FOUND. ONLY INCLUDED CB/VCSH MENTION AT FWA...DUE TO CONCERNS ON CONVECTIVE COVERAGE. AFTERNOON PERIOD WILL BE A DIFFICULT FORECAST DUE TO CONCERNS ON CONVECTIVE INITIATION. QUESTIONS ON CONVECTIVE DEBRIS/STRENGTH OF MID LEVEL WAVE/AND BEST INSTABILITY WILL MAKE PIN POINTING TSRA DIFFICULT. FELT BEST AVENUE AT THIS TIME IS TO RETAIN CB AND VCTS MENTION UNTIL BETTER TRENDS ARE ESTABLISHED. A SECOND ROUND OF CONVECTION IS POSSIBLE WED EVENING INTO THE NIGHT PERIOD AS A TS COMPLEX WILL DEVELOP OVER IA/MN AND PUSH SE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...HOLSTEN AVIATION...CHAMBERLAIN in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 336 PM CDT WED JUN 25 2008 .SHORT TERM /TONIGHT/... THE FORECAST TONIGHT IS QUITE COMPLEX AS THERE ARE SEVERAL FEATURES OVER/NEAR THE CWA. CURRENTLY WE ARE QUITE UNSTABLE WITH 4000 J/KG OF CAPE OVER THE SW THIRD OF IA BUT SHEAR IS QUITE WEAK...GENERALLY 20-25KTS OR LESS. OVER THE NORTHWEST...A FRONTAL BOUNDARY EXISTS FROM A LOW IN NE MN. THE FRONT EXTENDS INTO FAR NW IA THEN ALONG THE NEB/SDKTA BORDER. THERE IS WEAK CONVERGENCE ALONG THE SURFACE FRONT BUT SO FAR IT HAS NOT BEEN ABLE TO PRODUCE/SUSTAIN THUNDERSTORMS. ALOFT...THE FLOW IS WEAK AND THERE IS NOT A LOT OF SUPPORT. HOWEVER...RUC ANALYSIS DOES INDICATE A COUPLE OF WEAK VORT CENTERS...ONE OVER NW IA...PROBABLY AIDING IN THE SHOWERS UP THERE...AND ONE IN NORTHEAST KS MOVING INTO SW IA. CAPE VALUES IN THIS AREA ARE EVEN HIGHER THAN IN SW IA AND THERE ARE NO THUNDERSTORMS DEVELOPING YET. HAVING SAID ALL THIS...ANY ONE OF THESE FEATURES CAN TRIGGER STORMS TONIGHT AT ANY TIME. THE LACK OF DEVELOPMENT THUS FAR IS THE PERPLEXING PART. MID/UPPER LEVEL WIND FIELDS ARE BETTER OVER MN CLOSER TO THE LOW. I WOULD EXPECT DEVELOPMENT TO INITIATE THERE THEN TRAVEL DOWN THE FRONTAL BOUNDARY THIS EVENING. I BELIEVE THE NAM HAS A GOOD HANDLE ON THE SCENARIO DEVELOPING THE PRECIP FURTHER SOUTH...WHERE THE THE FRONT WILL EVENTUALLY SAG INTO THE HIGH CAPE AREA. LATER TONIGHT A LLJ DEVELOPS AND THIS WILL PROBABLY AID IN THE DEVELOPMENT OF AN MCS MOVING SLOWLY ACROSS THE STATE OVERNIGHT INTO THURSDAY. WITH THE HIGH LEVEL OF UNCERTAINTY OVER JUST WHERE INITIATION WILL BEGIN I HAVE PLACED CHANCE POPS OVER THE CWA FOR TONIGHT. THE HIGHEST POPS STILL REMAIN NORTH BUT WITH FAIRLY DEEP MOISTURE OVER THE SOUTH...ANY STORMS THAT DEVELOP DOWN THERE WILL ALSO PRODUCE VERY HEAVY RAINFALL. .LONG TERM /THU-WED/... MOST ACTIVE PERIOD REMAINS WITHIN THE FIRST 60 HOURS OF THE FORECAST PERIOD. A FEW THUNDERSTORMS POSSIBLY ONGOING AT THE START OF THE PERIOD AT 12Z THURSDAY. THE BIGGER SHOW IS STILL EXPECTED TO BE A DEVELOPING MCS OVER WYOMING LATE THIS EVENING THEN ROLL THROUGH SOUTH DAKOTA OVERNIGHT BEFORE REACHING NORTHERN IOWA DURING THE DAY ON THURSDAY. SOME SFC HEATING IS LIKELY AHEAD OF THE SYSTEM AND THIS SHOULD ALLOW FOR AN INCREASINGLY UNSTABLE AIR MASS TO DEVELOP FOR THE STORMS TO FEED ON. SEVERE STORMS ALONG WITH AREAS OF HEAVY RAINFALL WILL BE POSSIBLE. ADDITIONAL STORMS EXPECTED THURSDAY NIGHT BEFORE THE PRIMARY FRONTAL BOUNDARY ARRIVES ON FRIDAY. GOOD INSTABILITY LIKELY AGAIN ON FRIDAY WITH MIX LAYER CAPES OF 2000 TO 2500 J/KG HOWEVER THE MAIN UPPER LEVEL FORCING WILL PASS TO THE NORTH. STILL ENOUGH SHEAR WILL REMAIN FOR SOME SEVERE MULTICELL STORMS AND ISOLATED SUPER CELLS. THE WEEKEND WILL BE DOMINATED BY A LARGE UPPER LEVEL LOW MOVING SLOWING THROUGH THE WESTERN GREAT LAKES REGION BRINGING CYCLONIC FLOW TO IOWA. HAVE COOLED HIGH TEMPERATURES AND ADDED LOW POPS TO THE NORTHEAST FOR EACH AFTERNOON AS IMPULSES ROTATE AROUND THE UPPER LOW. COOL TEMPERATURES THROUGH THE COLUMN WILL LEAD TO SOME INSTABILITY DURING THE AFTERNOONS. GRADUALLY WARMER NEXT WEEK WITH THE NEXT BEST CHANCE OF PRECIPITATION ARRIVING TUESDAY NIGHT AND INTO WEDNESDAY. && .AVIATION...25/18Z DIFFICULT FORECAST TODAY AS THE MODELS ARE NOT HANDLING THE MOISTURE VERY WELL. LOW PRESSURE OVER MN HAS A COLD FRONT EXTENDING SW TO NR NW IA THEN INTO SERN SDKTA AND NRN NEB. THE MODELS ARE FAIRLY CONSISTENT IN BREAKING OUT PRECIP THIS EVENING AND OVERNIGHT BUT WITH WEAK TO NO UPPER LEVEL SUPPORT...CONVECTION WILL HAVE TO BE BASED LARGELY ON CONVERGENCE ALONG THE FRONT. ONCE THE STORMS START TO DEVELOP THEY SHOULD GO QUICKLY IN THE UNSTABLE ENVIRONMENT WE ARE IN. WE MAY NEED THE HELP OF THE LLJ TO GET THINGS GOING. IN THAT CASE IT WOULD BE LATER THIS EVENING. THERE IS A POSSIBILITY THAT THE STORMS MAY FIRE FURTHER SOUTH ALONG THE FRONT IN WHICH CASE THE SOUTHERN TAF SITES WOULD ALSO BE AT RISK OF STORMS. I HAVE LEANED TOWARDS THIS SOLUTION AS SAT PIX SHOWING CONVECTIVE ELEMENTS OVER SRN/CENT NEB. MVFR COND W/ LCL IFR COND WL PREVAIL IN TSRA. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ LONG TERM...DONAVON SHORT TERM/AVIATION...FAB ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 1139 AM MDT TUE JUN 24 2008 .UPDATE... 1041 AM MDT TUE JUN 24 2008 MADE A FEW MINOR UPDATES TO THE FORECAST...MAINLY TO FINE TUNE SKY AND WX GRIDS. PRIMARY CONCERN FOR THE AFTERNOON WILL BE PRECIPITATION CHANCES YET AGAIN. MODIFIED DNR...LBF AND DDC SOUNDINGS WITH EXPECTED AFTERNOON TEMPERATURES INDICATE 1000-1500 J/KG OF CAPE AND MINIMAL CINH ACROSS THE NORTH AND WEST. ALTHOUGH SFC FEATURES ACROSS THE AREA REMAIN POORLY DEFINED...SFC CONVERGENT AREA APPEARS BETWEEN GLD AND ITR WHICH MAY PROVIDE A FOCUS FOR CONVECTION. LATEST RUC SEEMS TO CATCHING ON TO THIS FEATURE AS WELL...AND HAVE UPPED POPS TO SCT ACROSS WESTERN CWA. SUBSIDENCE SHOULD BE FAIRLY WIDESPREAD ACROSS THE AREA TODAY SO CONFIDENCE NOT MUCH HIGHER THAN 30 PERCENT ATTM. IF THUNDERSTORMS DEVELOP...HAVE SOME CONCERNS ABOUT FLOODING ACROSS YUMA..DUNDY...HITCHCOCK AND CHEYENNE COUNTY WHERE 1-2 INCHES OF RAIN FELL LAST NIGHT. WITH SUBSIDENCE AND SOME QUESTIONS ABOUT COVERAGE CONFIDENCE NOT HIGH ENOUGH FOR ANY KIND OF HIGHLIGHT. JRM && .DISCUSSION... 126 AM MDT TUE JUN 24 2008 PRIMARY CONCERNS WILL THE NEXT FEW DAYS WILL REVOLVE AROUND TEMPS AND THE DIFFICULTY OF PINPOINTING THE BEST CHANCES FOR PRECIP. FOR THE REST OF THIS MORNING...SUBSIDENCE INVERSION SHOULD SET UP ON THE BACK SIDE OF THE DEPARTING SHORTWAVE TROUGH WHICH WILL ALLOW FOR THE DEVELOPMENT OF LOW STRATUS WHICH WILL HANG AROUND THROUGH THE MORNING HOURS BEFORE MIXING OUT. WINDS WILL BECOME SOUTHEASTERLY AS ANOTHER WEAK SHORTWAVE BEGINS TO IMPACT THE TRI STATE REGION LATE THIS EVENING. GIVEN THE LOCALIZED CONVERGENCE AND REMAINING OUTFLOW BOUNDARIES FROM MONDAY EVENING`S CONVECTION...CAN`T RULE OUT AN ISOLATED THUNDERSTORM. NOT EXPECTING NEARLY THE AREAL COVERAGE THAT WE SAW MONDAY EVENING HOWEVER AS BEST LARGE SCALE FORCING FOR ASCENT REMAINS WELL NORTH OF OUR AREA. STRONG THERMAL RIDGE SETS UP OVER THE CENTRAL HIGH PLAINS ON WEDNESDAY WITH H85 TEMPS REACHING THE LOW 30`S C OVER EASTERN COLORADO PER THE 00Z/24 ECMWF. COULD SEE A FEW LOCATIONS PUSH THE CENTURY MARK. LEE SURFACE CYCLOGENESIS PROGGED TO DEVELOP OVER THE PALMER DIVIDE WEDNESDAY AFTERNOON WHICH COULD AID IN THE DEVELOPMENT OF A MCS OVER WESTERN NEBRASKA BY LATE WEDNESDAY AFTERNOON. THIS COMPLEX IS FORECASTED TO SLIDE SOUTHEASTWARD OVER MUCH OF THE CWA DURING THE OVERNIGHT HOURS. MODELS TENDING TO FAVOR THE NORTHEAST HALF AND HAVE TWEAKED POPS TOWARD THIS DIRECTION. SIMILAR SITUATION SETTING UP THURSDAY BUT FORCING FOR ASCENT APPEARS TO BE WEAKER SO WILL MAINTAIN ONLY LOW SLIGHT CHANCE POPS FOR NOW. WITH H85 TEMPS MAINTAINING IN THE UPPER 20`S C...MADE ONLY SLIGHT TWEAKS TO THE GOING FORECAST MAX TEMPS FOR THURSDAY. BROKEN RECORD FOR FRIDAY AS BOTH EC AND OPERATIONAL GFS MAINTAIN ESSENTIALLY ZONAL MEAN FLOW WITH YET ANOTHER SHORTWAVE TROUGH MOVING INTO THE REGION BY LATE FRIDAY AFTERNOON. AS IS TYPICAL WITH THIS TYPE OF PATTERN...TIMING AND LOCATION OF PRECIP IS DIFFICULT TO DETERMINE A FEW DAYS OUT SO HAVE GENERALLY BROAD BRUSHED SLIGHT CHANCE POPS OVER THE CWA. NO CHANGES WERE MADE BEYOND FRIDAY NIGHT. FOLTZ && .AVIATION... 1139 AM MDT TUE JUN 24 2008 FOR 18Z TAFS...VFR CONDTIONS WILL PREVAIL ACROSS THE AREA THROUGH THE PERIOD. ISOLD THUNDERSTORMS WILL ARE POSSIBLE BETWEEN 21-02Z...MAINLY NEAR KGLD. IF STORMS FORM...THEY SHOULD BE FAIRLY HIGH BASED WITH VARIABLE AND GUSTY WINDS BEING PRIMARY IMPACT. JRM && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 1028 AM EDT WED JUN 25 2008 .SYNOPSIS... HIGH PRESSURE WILL SLIDE SOUTH OF THE AREA TODAY AS A WEAK FRONTAL BOUNDARY MOVES DOWN FROM THE NORTHWEST. THE FRONT WILL STALL ACROSS THE REGION TONIGHT. A WAVE OF LOW PRESSURE TRACKING ALONG THE FRONT WILL APPROACH ON THURSDAY AND TRACK ACROSS THE AREA THURSDAY NIGHT. THE LOW WILL MOVE EAST ON FRIDAY FOLLOWED BY COOLER HIGH PRESSURE OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... BASED ON LATEST RADAR AND SATELLITE TRENDS HAVE REMOVED ANY REFERENCE TO SHOWERS ACROSS THE NORTH THIS AFTERNOON. CANADIAN RADAR MOSAIC AND OBSERVATIONS ARE CURRENTLY SHOWING ANY SHOWER ACTIVITY WELL BACK ACROSS NORTHWEST QUEBEC PROVINCE. LATEST RUC SEEMS TO HAVE A GOOD HANDLE ON THE SITUATION AND KEEPS THE US DRY THROUGH THIS AFTERNOON. MOISTURE ASSOCIATED WITH ANOTHER SHORTWAVE AND ASSOCIATED LOW WILL THEN BEGIN SPREADING INTO THE REGION LATE TONIGHT WITH SOME SHOWERS MOVING INTO THE AREA TOWARD MORNING. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... ANOTHER ROUND OF WET WX IS IN STORE THIS PERIOD. THE MAIN CHALLENGES WILL BE THE FRONTAL BOUNDARY DROPPING S ACROSS THE CWA AND WAVE OF LOW PRES MOVING ALONG THE BOUNDARY. CONCERNS ARE...WHERE TO PLACE CONVECTION AND TRACK OF SFC LOW. DECIDED ON A 33% BLEND OF THE SREF/GFS40 AND NAM INTO THURSDAY EVENING AND THEN WENT W/THE SREF/GFS40 MATCHING THIS BLEND W/THE ECMWF AS SFC LOW TRACKS THROUGH CNTL MAINE AND NOT AS FAR N AS THE NAM HAS IT ACROSS NERN MAINE. THEREFORE...PUSHED POPS UP TO LIKELY AND CATEGORICAL ACROSS MOST OF THE CWA INTO THURSDAY EVENING W/THE EXCEPTION OF THE COAST AS HIGH CHC POPS WERE USED. AIRMASS LOOKS STABLE ENOUGH ACROSS THE NRN 1/2 OF THE CWA TO GO W/STRATIFORM RAIN W/AN ESE FLOW. FURTHER S ACROSS CNTL AND DOWNEAST AREAS...ADDED THE MENTION OF TSTMS THURSDAY AFTERNOON INTO THURSDAY EVENING AS MDL SOUNDINGS INDICATE HIGHEST INSTABILITY IN THESE AREAS. NEED TO BE AWARE OF HEAVY RAFL ESP WHERE CONVECTION OCCURS AS KIS ARE FCST TO PUSH MID 30S...PWS TO BE AT 1.5 INCHES AND DECENT ESE INFLOW OVERRIDING THE FRONTAL BOUNDARY. AREAL QPF AMOUNTS ARE A BLEND OF THE SREF/HPC AND GFS WHICH YIELD ANYWHERE FROM .50-.75 INCHES ACROSS NRN AND CNTL AREAS TO AROUND .25 OF AN INCH. HIGHER AMOUNTS OF COURSE CAN BE EXPECTED IN HEAVIER RAFL ESP IN CONVECTION. ADDED TSTMS AGAIN FOR CNTL AND DOWNEAST AREAS DUE TO PROXIMITY OF THE FRONT AND 30-35 KT MID-LVL JET PROGGED TO MOVE ACROSS THESE AREAS. KEPT DAYCREWS THURSDAY MAXES AS THEY MATCH CLOSE TO LATEST GUIDANCE NUMBERS. FRIDAY/S MAXES WERE ADJUSTED DOWNWARD TO THE MID 60S ACROSS NRN MAINE WHERE ELY FLOW WILL KEEP CLOUDS AND RAFL LIMITING MUCH WARMING. && .LONG TERM /FRIDAY THROUGH TUESDAY/... GMOS WAS LOADED AND THEN ADJUSTED COMPARING IT TO THE LATEST ECMWF AND GFS ENS. BIGGEST CONCERN IS FOR THE WEEKEND AS THE LATEST ECMWF HAS NOW BECOME MORE AGGRESSIVE W/BRINGING RAFL INTO THE CWA BY SATURDAY NIGHT WHILE THE OPERATIONAL GFS40 HAS HIGH PRES DROPPING DOWN ACROSS THE CWA. CONFIDENCE NOT THAT HIGH GIVEN SUCH A DISPARITY. HOWEVER...THE LATEST GFS ENS DOES SHOW SOME SUPPORT OF THE OPERATIONAL GFS40. THEREFORE...DECISION WAS TO LEAN W/A DRIER SCENARIO FOR SATURDAY INTO EARLY SUNDAY KEEPING CHC POPS ACROSS THE SRN TIER OF THE CWA BY SUNDAY AFTERNOON. HIGH PRES RIDGE SHOWS SIGNS OF BREAKING DOWN AND SHIFTING E BY SUNDAY NIGHT. LOW PRES IS FCST TO TRACK THROUGH WRN QUEBEC ON MONDAY BRINGING A FRONTAL BOUNDARY ACROSS THE REGION W/INCREASING CHCS FOR SHOWERS AND POSSIBLE TSTMS. GMOS POPS SHOWED 40% FOR THE CWA MONDAY INTO TUESDAY AND ATTM SAW NO REASON TO DEVIATE FROM THEM. A MODEST ADJUSTMENT WAS MADE TO THE TEMPERATURES ESP MINIMUMS AS CLOUDS AND SSW FLOW WILL ALLOW FOR A MORE HUMID AIRMASS TO RETURN. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: VFR CONDITIONS ARE EXPECTED ACROSS THE AREA TODAY. CONDITIONS MAY LOWER TO IFR ACROSS THE NORTH LATE TONIGHT BUT REMAIN VFR OVER DOWNEAST AREAS. SHORT TERM: LOOKS LIKE IFR/MVFR CONDITIONS RIGHT INTO THURSDAY NIGHT AS THE FRONTAL BOUNDARY DROPS S. SOME IMPROVEMENT POSSIBLE LATER ON FRIDAY TO VFR AS THE FRONT SAGS FURTHER S AND SOME DRIER AIR RETURNS. LATEST INDICATIONS ARE THE VFR LOOKS GOOD INTO THE WEEKEND. && .MARINE... NEAR TERM: WINDS AND SEAS WILL REMAIN BELOW SCA TODAY AND TONIGHT. DRIER AIR WILL BRING GOOD VISIBILITIES TODAY. SHORTER TERM: NO HEADLINE ES FORESEEN ATTM. ADJUSTMENTS WERE MADE TO THE WNAWAVE ESP LAST FEW PERIODS TO LOWER WAVE HEIGHTS BACK 1-2 FT. LOOKS LIKE SWELL GENERATION AS ESE FLOW SETS UP. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...DUDA/BLOOMER SHORT TERM...HEWITT LONG TERM...HEWITT AVIATION...BLOOMER MARINE...BLOOMER/HEWITT me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 229 PM EDT WED JUN 25 2008 .SYNOPSIS... HIGH PRESSURE CONTINUES TO BUILD OVER THE REGION THROUGH THIS EVENING...SHIFTING OFFSHORE THURSDAY INTO FRIDAY. A COLD FRONT APPROACHES THE REGION ON SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... HIGH PRES OVER THE RGN WL CONTINUE TO DOMINATE WX TDA. DRY AIRMASS...PLENTY OF SUNSHINE AND RISING HGTS ALLOW TEMPS TO BE A FEW DEGREES WARMER THAN YDA. WENT WITH NAM/FWC BLEND (BLO WARM MAV GUIDANCE)...YIELDING HIGHS TDA INTO LWR 90S FOR MUCH OF INTERIOR VA/NC (SEE CLIMATE SECTION BELOW). COOLER U80S/ARND 90 AT IMMEDIATE COASTLINE (L/M80S IVOF OXB-WAL). WITH DRY DOWNSLOPE WINDS AND LOOKING AT MIXED LAYER RUC13 LOWERED DEWPOINTS IN THE WEST TO LOWER 50S OTHERWISE MID TO UPPER 50S DEWPOINTS. ALONG THE COAST DEWPOINTS IN THE 60S. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... HIGH PRES SHIFTS OFFSHORE ERY THU...ALLOWING RETURN FLOW TO STRENGTHEN. HIGHS EXPECTED AT LEAST IN THE MID 90S BOTH DAYS...WITH GUIDANCE AND LOCAL THICKNESS SCHEMES POINTING TWDS THU AS THE WARMEST DAY OF THE PERIOD. ONCE AGAIN APPLIED A MAV/FWC BLEND FOR MAX T...RESULTING IN MID 90S (WITH A FEW UPR 90S) INLAND THU...L/M 90S INTO TIDEWATER AND COASTAL LOCALES (XCEPT IMMEDIATE COASTLINE). THESE VALUES ARE AGAIN JUST BLO MAV GUID...BUT ARE A FEW DEGREES HIGHER THAN LOCAL TKNS SCHEMES WUD DICTATE. KEPT ISO WORDING FOR TSRA FOR BOTH AFTNS FOR SOME TYPICAL DIURNALLY DRIVEN CONVECTION. WHILE MIDLVL CAP APPEARS STRONG...BUT CAN`T RULE OUT A FEW RENEGADE STORMS POPPING UP (PWATS INCREASE MODESTLY BY THU AFTN). SPC HAS SRN HALF OF CWA IN GENERAL TSTM AREA FOR THU. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... VRY WRM AND RATHER HUMID THRU THE PERIOD WITH GENERALLY SLGT OR SML CHCS FOR SHRAS/TSRAS FOR MUCH OF THE AREA THRU MON...DUE TO THE APPROACH AND SLOW PASSAGE OF A COLD FRNT. THE BNDRY WILL LIKELY MOVE OFF THE CST DURING TUE...SO HAVE SLGT OR SML CHCS IN ERN CNTIES. ALTHO TEMPS MAY END UP WRMER...GOING WITH HI`S RANGING FM THE MID 80S TO LWR 90S AT THIS TIME. MIN TEMPS WILL GENERALLY RANGE FM THE MID 60S TO LWR 70S. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... SOUTH/SOUTHEASTERLY SURGE UP BAY TO AFFECT COASTAL SITES TONIGHT (ECG/ORF/PHF) WITH GUSTS UP TO 20 KTS AT ORF. OTW...SMOKE FROM THE TWO ONGOING FIRES THE MAIN CONCERN INTO THE WEEKEND. LIGHT AND VARIABLE WINDS THIS AFTN ARE KEEPING THE SMOKE PLUMES NEAR THE FIRES. SURGE THIS EVENING SHOULD BRING PLUME TO PHF...THEN A SWITCH TO SOUTHWESTERLY WINDS AFTER 04Z SHOULD BRING SMOKE TO ORF/ECG. CHANCE OF SUPER FOG AGAIN THUR MORN AT ECG/ORF...ESP IF WINDS/MIXING DIMINISH AND SKIES CLEAR TOWARDS 08Z. HIGH PRESSURE TO DOMINATE THE REGION...LIMITING CHANCES OF PRECIP/KEEPING VFR CONDS...INTO SATURDAY. NEXT CHANCE OF WIDESPREAD REDUCES AVN CONDS SATURDAY NIGHT THROUGH SUNDAY AHEAD OF CD FROPA. && .MARINE... SFC HI PRES RMNS OFFSHR AND IN CONTROL INTO THE WKND...RESULTING IN PREVAILING SSW FLO (AOB 15 KT). HAVE HOISTED SCA FLAGS FOR SRLY SURGE TONIGHT AS HIGH SLIPS OFFSHORE...WINDS ACROSS SRN CHES BAY TO GUST TO AROUND 20 KTS FROM 21Z TO 05Z. WK CDFNT APPROACHES FM THE NW SAT NGT/SUN. && .FIRE WEATHER... CURRENT SMOKE PLUMES MOVING NORTH FROM THE FIRES OVER PARTS OF HAMPTON ROADS AND INTO NORTHEAST NORTH CAROLINA. LOOKING AT TRAJECTORY FORECAST AND STREAMLINES SHOWS THE SEA BREEZES HOLDING THE SMOKE TO THE WEST UNTIL EVENING. BY TONIGHT WILL HAVE TO WATCH FOR MORE DENSE FOG FORMING WITH THE SMOKE TO REDUCE VISIBILITIES OVER LARGER AREAS. ISSUED NPW FOR DENSE SMOKE AS VISIBILITIES HAVE BEEN AROUND A MILE OR LESS IN SOME LOCATIONS. && .CLIMATE... LOOKS LIKE A HOT FINISH FOR JUNE (WHICH HAS ALREADY BEEN HOT). THROUGH THE 24TH...RIC AVG TEMP IS 78.2 F...AND ORF IS 78.3 F. BASED ON CURRENT FCST FOR NEXT 6 DAYS...APPEARS AS IF 2008 WILL RANK AS EITHER 2ND OR 3RD WARMEST ALL TIME FOR RICHMOND AND 3RD OR 4TH WARMEST ALL TIME AT NORFOLK. _______________5 HOTTEST JUNES (AVG TEMPERATURE)_______________ RANK........RICHMOND...........NORFOLK......... 1........79.2 F (1943)......80.1 F (1943) 2........78.8 F (1895)......79.5 F (1994) 3........78.4 F (1892)......78.8 F (1934) 4......**78.2 F (2008)**....78.5 F (1952) 5........78.1 F (1890)......78.48F (1989) OTHER NOTABLE POSSIBILITIES... .RICHMOND... ***AVG HIGH TEMPERATURE FOR THE MONTH WILL LIKELY BE HIGHEST ALL TIME (90.0 F IN 1984 IS CURRENTLY THE HIGHEST). ***IF THE NEXT 6 DAYS (25TH-30TH) ALL HIT 90F (OR HIGHER)...WILL THEN HAVE 20 DAYS OF 90+ THIS JUNE (WHICH WOULD TIE 1943 FOR THE MOST). .NORFOLK... ***AVG HIGH TEMPERATURE FOR MONTH HAS A CHANCE TO BE HIGHEST ALL TIME (88.8 F IN 1943 IS CURRENTLY THE HIGHEST). && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 1 AM EDT THURSDAY FOR ANZ630>632. && $$ SYNOPSIS...MAM NEAR TERM...JAB/MAM SHORT TERM...MAM LONG TERM...ALS/TMG AVIATION...BAJ MARINE...ALB/BAJ FIRE WEATHER...ALB CLIMATE...LKB md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1010 PM EDT WED JUN 25 2008 .UPDATE...LATEST RUC ANALYSIS AND IR/WV/RADAR IMAGERY SHOW A WEAK SURFACE LOW TRANSVERSING OVER WESTERN LAKE SUPERIOR WITH WARM FRONT EXTENDING JUST NORTH OF THE LAKE SUPERIOR SHORELINE. SHOWERS AND THUNDERSTORMS...ALL SUB-SEVERE...CONTINUE TO DEVELOP JUST SOUTH OF THE SURFACE LOW WITHIN THE WARM SECTOR WITH SOME HELP FROM ADDED CONVERGENCE AS A RESULT OF LAKE BREEZES. THESE SHOWERS AND STORMS HAVE BEEN DISSIPATING AS THEY HEAD TOWARDS EASTERN ALGER COUNTY WHERE LOWER THETAE AIR RESIDES. ADDITIONAL THUNDERSTORMS ALSO HAVE BEEN REDEVELOPING AHEAD OF THE PARENT SHORTWAVE OVER THE ARROWHEAD OF MINNESOTA. FARTHER SOUTH...WEAK COOL FRONT/SURFACE TROUGH...WHICH EXTENDS ACROSS WESTERN WISCONSIN...HAS BEEN DORMANT IN REGARDS TO IGNITING CONVECTION DUE TO CAPPING ISSUES JUDGING BY 00Z GRB SOUNDING AS WARMING AIR SURGES NE AHEAD OF THE TROUGH. CLOSER TO HOME...A ROGUE SHOWER DEVELOPED OVER NE LOWER THIS EVENING BUT QUICKLY DISSIPATED LEAVING MOSTLY CLEAR TO PARTLY CLOUDY SKIES OVER MOST LOCALES. FOR THE REST OF THE NIGHT...THE WEAK SURFACE LOW WILL CONTINUE ITS TREK EAST AS HIGHER LOW LEVEL THETAE AIR WILL SURGE INTO THE REGION AHEAD OF ITS SURFACE TROUGH. STRONGEST (ALBEIT PRETTY MODEST) 700-500MB QG FORCING WILL RESIDE ACROSS EASTERN UPPER CLOSEST TO THE SHORTWAVE WITH A LITTLE 850-700MB -DIVQ CLIPPING NORTHERN LOWER TOWARDS THE TIP OF THE MITT. WITHIN THE THETAE AXIS...18Z NAM SHOWS 300-600 J/KG OF ELEVATED CAPE DEVELOPING BETWEEN 03-06Z...BUT CURRENT CONVECTION ACROSS THE U.P. APPEARS SURFACE BASED AND SHOULD DIMINISH SOMEWHAT AS DIURNAL INSTABILITY WANES. THE NAM ALSO TRIES TO DEVELOP A MODEST 25-30KT LLJ THAT POKES INTO EASTERN UPPER AFTER 03Z THAT CAN BOOST CONVERGENCE IN ADDITION TO THE CYCLONIC FLOW AROUND THE SURFACE LOW. THIS SEEMS TO POINT TOWARDS THE CONVECTION SURVIVING THE MARCH AS IT REACHES WHITEFISH POINT TO THE SOO LATER TONIGHT AND WILL BUMP UP POPS TO LIKELY. OVER NORTHERN LOWER...ABSENCE OF CONVECTION ALONG THE TROUGH THIS AFTERNOON MAKES ME THINK CAPPING WILL CONTINUE TO BE A PROBLEM FOR STORMS TO DEVELOP DESPITE AMPLE INSTABILITY ABOVE THE CAP. LACK OF UPPER LEVEL SUPPORT...AND WEAKENING SURFACE CONVERGENCE ALONG THE TROUGH DOES NOT HELP EITHER. HOWEVER...STILL A LITTLE WARY OF REMOVING PRECIP ALTOGETHER GIVEN ELEVATED INCOMING THETAE BOOST. SO WILL HEDGE AND GO ISOLATED THUNDER FOR NORTHERN LOWER OVERNIGHT. MPC && .PREV DISCUSSION... /ISSUED 707 PM EDT WED JUN 25 2008/ AVIATION...ANOTHER CHALLENGING FORECAST IN THE AVIATION DEPARTMENT TONIGHT. WEAK AREA OF LOW PRESSURE WILL TRACK ALONG A LOW LEVEL BOUNDARY OVER LAKE SUPERIOR WHILE DRAGGING A SURFACE TROUGH ACROSS THE REGION LATE TONIGHT INTO TOMORROW MORNING. NARROW CORRIDOR OF A JUICIER AIRMASS WILL MOVE IN AHEAD OF THE TROUGH...WHICH WILL PROVIDE SOME INSTABILITY FOR SHOWER AND THUNDERSTORM DEVELOPMENT. HOW MUCH LIFT IS THE KEY QUESTION WHETHER THE TAF SITES WILL REMAIN DRY. FEEL BETTER CHANCES WILL REMAIN ACROSS EASTERN UPPER...AND A SHOWER COULD SNEAK INTO PLN AFTER MIDNIGHT. HOWEVER...BELIEVE LIFT WILL BE TOO WEAK FOR PRECIP AT TVC/APN. SO WILL MAINTAIN SCT LOW LEVEL CLOUDS AHEAD OF THE TROUGH. ONCE THE TROUGH EXITS BY AFTERNOON...DRIER AIR WILL LIKELY ERODE ANY CUMULUS CLOUDS THAT POP UP AT ALL TAF SITES EXCEPT APN WHERE A POTENTIAL LAKE BREEZE MAY KEEP A FEW CLOUDS AROUND. MPC PREV DISCUSSION... /ISSUED 329 PM EDT WED JUN 25 2008/ DISCUSSION...MID AFTERNOON OBSERVATIONAL AND NUMERICAL GUIDANCE ANALYSIS SHOWS PAIR OF EARLIER CONVECTIVELY INDUCED VORT LOBES...ONE OVER SOUTHERN LAKE MICHIGAN WITH THE OTHER OVER NORTH CENTRAL WISCONSIN...MAKING THEIR WAY EAST IN BROAD ZONAL WEST FLOW THAT LIES ACROSS THE NORTHERN CONUS AND SOUTHERN CANADA. AS FEARED...DESPITE SOMEWHAT INCREASING SUPPORT...AFTERNOON MIXING AND PRESENCE OF MID LEVEL CAP PREVENTING ANY SHOWER ACTIVITY OVER NORTHERN MICHIGAN (BESIDES SOME REMNANT SPRINKLES MAKING THEIR WAY ACROSS GLADWIN AND ARENAC COUNTIES FROM EARLIER DOWNSTATE CONVECTION). OTHERWISE... PLENTY OF SUNSHINE AND LIGHT SOUTHWEST FLOW ON BACKSIDE OF DEPARTING SURFACE RIDGE AXIS HAS LEAD TO A RATHER WARM SUMMER DAY...WITH AFTERNOON READINGS WELL INTO THE 70S AND LOWER 80S. FARTHER UPSTREAM...POTENTIAL NEXT WEATHER MAKER OF INTEREST IS NORTHERN MINNESOTA LOW AMPLITUDE SHORTWAVE AND ATTENDANT LOW PRESSURE/COLD FRONT MAKING STEADY EAST PROGRESS. FORECAST CONCERNS TONIGHT AND THURSDAY CENTER ON CONVECTIVE POTENTIAL AS THIS COLD FRONT PIVOTS SOUTHEAST ACROSS THE AREA. TONIGHT...THINKING THAT ANY LATE AFTERNOON ISOLATED SHOWERS AND STORMS THAT MANAGE TO DEVELOP WILL QUICKLY BE ON THE WANE...WITH ALL ATTENTION THEN TURNING TO UPSTREAM APPROACHING COLD FRONT. EXPECT CONVECTION TO QUICKLY FIRE THIS AFTERNOON ACROSS WESTERN UPPER MICHIGAN AND NORTH CENTRAL WISCONSIN AS CONVERGENCE AXIS WORKS ON 1500+ J/KG OF SURFACE BASED CAPE. SHOWERS AND STORMS WILL WORK EAST THIS EVENING FOLLOWING MOISTURE AXIS...PUSHING INTO EASTERN UPPER MICHIGAN LATER THIS EVENING. AFTER THAT...SEVERAL QUESTIONS ARISE AS OVERALL CONVERGENCE AND INSTABILITY WEAKENS AHEAD OF FRONTAL SYSTEM. THUS...FEEL COVERAGE AND INTENSITY OF SHOWERS AND STORMS WILL FOLLOW SUITE AS THEY DROP SOUTHEAST. THEREFORE...WILL TAPER POPS FROM NORTH TO SOUTH OVERNIGHT...NOT BRINGING IN CHANCE WORDING TO OUR SOUTHEAST ZONES UNTIL AFTER 09Z. AS FOR SEVERE WEATHER...REGION REMAINS OUT OF LATEST SPC SLIGHT RISK WORDING...WHICH SEEMS SUPPORTED BY BETTER BULK SHEAR REMAINING NORTH OF THE AREA AND RELATIVELY HIGH FREEZING LEVELS (>13.0 KFT). STILL...THINKING THE STRONGEST STORMS WILL BE CAPABLE OF SOME SMALL HAILS AND BRIEF GUSTY WINDS...ESPECIALLY LATER THIS EVENING ACROSS EASTERN UPPER MICHIGAN. THURSDAY...COLD FRONT CONTINUES TO DROP SOUTHEAST DURING THE MORNING AS PARENT LOW PUSHES INTO QUEBEC. WHILE MODELS REMAIN DRY DURING THE MORNING...HATE TO RULE OUT AT LEAST AN ISOLATED SHOWER OR STORM BEFORE FRONTAL PASSAGE. EARLY AFTERNOON HOURS COULD GET QUITE INTERESTING OVER FAR SOUTHEAST SECTIONS OF THE AREA IF COLD FRONT STALLS FROM INTENSE MORNING WARMING. MODIFYING A NAM-WRF SOUNDING (IGNORING OVERZEALOUS LOW 70 DEWPOINTS) YIELDS 1500+ J/KG MEAN LAYER CAPE. WILL KEEP LOW POP MENTION FOR THIS POSSIBILITY THROUGH 21Z BEFORE FRONT SAGS FAR ENOUGH SOUTH TO SUPPRESS CONVECTION. OTHER STORY WILL BE RATHER WARM TEMPERATURES...WITH READINGS PUSHING THE UPPER 80S SOUTHEAST OF WEST BRANCH. FARTHER NORTH...MID 70S TO LOWER 80S ARE EXPECTED...WITH TEMPERATURES SEVERAL DEGREES COOLER ALONG THE LAKE MICHIGAN SHORELINE. MSB THURSDAY NIGHT THRU FRIDAY NIGHT...STILL EXPECT A DRY THURSDAY NIGHT WITH WEAK RIDGING...SUBSIDENCE AND DRY AIR OVERHEAD. CONVECTIVE ACTIVITY PICKS UP AGAIN ON FRIDAY AS MOISTURE AND INSTABILITY INCREASE ACROSS THE WRN GREAT LAKES ALONG AND AHEAD OF A WARM FRONT. THIS FRONT IS ASSOCIATED WITH AN UNSEASONABLY STRONG LOW PRESSURE SYSTEM APPROACHING THE WRN GREAT LAKES REGION (MORE ON THIS SYSTEM BELOW). BEST INSTABILITY AND 850 THETA-E ADVECTION WILL OCCUR WELL SW OF OUR CWA OVER KANSAS...MISSOURI AND ILLINOIS (AN AREA THAT CERTAINLY DOES NOT NEED MORE RAIN). EXPECT BEST CHANCE OF SVR TSRA WILL BE IN THIS AREA WHERE STRONGER WIND FIELDS AND BETTER WIND SHEAR EXIST. STILL...CANNOT RULE OUT AN ISOLD SVR STORM FRIDAY AFTERNOON AND NIGHT WITH MODEST WIND SHEAR...CAPES APPROACHING 1000 J/KG AND THE 850 MB THETA E RIDGE AXIS JUST UPSTREAM. WILL MAINTAIN CHANCE OF SHRA/TSRA FOR FRIDAY AND LIKELY POPS FOR FRIDAY NIGHT. LOW TEMPS WILL FALL INTO THE UPPER 50S/LOWER 60S BOTH THURSDAY NIGHT AND FRIDAY NIGHT. HIGH TEMPS WILL WARM INTO THE UPPER 70S/LOWER 80S FRIDAY AFTERNOON. SATURDAY THRU WEDNESDAY...IMPRESSIVE UPPER LOW WILL DIVE SE OUT OF S CENTRAL CANADA INTO NRN MICHIGAN ON SATURDAY. SURFACE REFLECTION BECOMES VERTICALLY STACKED WITH THE DEEP CLOSED 500 MB LOW... RESULTING IN A VERY SLOW EASTWARD PROGRESSION AWAY FROM THE STATE FOR SUNDAY INTO MONDAY. AS MENTIONED ABOVE...SYSTEM IS UNSEASONABLY STRONG AND VERY DYNAMIC. IN ADDITION...LATEST MODELS STILL SUGGEST MAIN AREA OF CONVECTION ALONG AND AHEAD OF THE LOW AND COLD FRONT WILL IMPACT OUR AREA DURING PEAK HEATING SATURDAY AFTERNOON/EVENING. HAVE BOOSTED POPS TO LIKELY FOR SATURDAY AS MICHIGAN FINDS ITSELF WITHIN THE INSTABILITY AND MOISTURE AXES AHEAD OF THE SYSTEM. HAVE ALSO INCREASED POPS TO LIKELY FOR SATURDAY NIGHT AND SUNDAY AS THE STACKED LOW MOVES THRU NRN MICHIGAN AND THEN STALLS OVER LAKE HURON. CHANCE POPS SHOULD REMAIN IN THE FORECAST THRU MONDAY AS AMPLE LOW LEVEL MOISTURE...GOOD CYCLONIC FLOW AND SUFFICIENT INSTABILITY REMAIN OVER THE AREA AS THE 500 MB COLD POOL ARRIVES. MONDAY NIGHT THRU WEDNESDAY STILL LOOKS DRY AS HIGH PRESSURE/RIDGING/DRIER AIR SETTLE INTO THE REGION. EXPECT HIGH TEMPS MAINLY IN THE 70S AND LOWS IN THE 50S THRU THE PERIOD. AVIATION... /ISSUED 140 PM EDT WED JUN 25 2008/ BESIDES SOME SCATTERED CU AND CIRRUS...ANOTHER UNEVENTFUL DAY ACROSS ALL TAF SITES AS HIGH PRESSURE RIDGING REMAINS IN CONTROL. MORE OF THE SAME EXPECTED THROUGH THE EARLY EVENING BEFORE APPROACHING FRONTAL SYSTEM BRINGS THE THREAT OF SOME WIDELY SCATTERED SHOWERS AND STORMS. AT THIS TIME...MUCH UNCERTAINTY EXISTS REGARDING BOTH TIMING AND COVERAGE OF SHOWERS AND STORMS...SO HAVE SIMPLY LEFT ANY MENTION OUT OF TAFS. WIND SHIFT TO MORE WNW EXPECTED THURSDAY. MSB && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. LS...NONE. && $$ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 142 AM EDT WED JUN 25 2008 UPDATED FOR 18Z TAF ISSUANCE .SYNOPSIS (ISSUED AT 557 AM EDT WED)... WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS WITH SEVERAL SHORTWAVE TROUGHS OF NOTE. ONE SHRTWV MOVING ACROSS LAKE SUPERIOR SUPPORTED A LINE OF ISOLD SHRA EARLY THIS MORNING STRETCHING WEST TO EAST ACROSS LAKE SUPERIOR ALONG A SFC TROF INTERSECTING THE KEWEENAW PENINSULA. ANOTHER SHORTWAVE OVER SRN MANITOBA WILL BE POISED TO MOVE ACROSS THE UPR GREAT LAKES THIS AFTERNOON AND EVENING BRINGING THE POTENTIAL FOR ISOLD TO SCT SHRA/TSRA. && .DISCUSSION... TODAY...THE SRN SASK SHRTWV WILL MOVE ACROSS THE AREA. MODELS SUGGEST GREATER INSTABILITY WILL DEVELOP AS LOW LEVEL MOISTURE ADVECTS TOWARD THE WRN LAKES FROM IA AND SRN MN. FCST TEMP/DEWPOINTS NEAR 80/60 WOULD INDICATE CAPE VALUES BETWEEN 500-1000 J/KG. IF THIS INSTABILITY IS REALIZED...THERE IS SUFFICIENT DEEP LAYER SHEAR OF 40-50KT TO LEAD TO A FEW ISOLD SVR STORMS. THE BIG QUESTION IS WILL DRIER (MID-UPR 50S) DEWPOINTS MIX TO THE SFC SIMILAR TO WHAT HAPPENED YESTERDAY AND LIMIT AND/OR INHIBIT CONVECTION. LOOKING AT HOW DRY UPSTREAM 00Z SNDGS AT KINL AND KMPX ARE...I CERTAINLY THINK THAT THE NAM AND GFS MODEL DEWPOINTS ARE OVERDONE. IF DRY AIR ALOFT DOES LOWER SFC DEWPOINTS INTO THE MID-UPR 50S...IT WILL HARD TO BREAK THROUGH MID LVL CAP AT 750 MB. SPC MUST ALSO BE THINKING ALONG LINES OF A REDUCED THREAT OR DRIER SOLN AS THEY HAVE DROPPED OUR CWA OUT OF SLIGHT RISK FOR DAY1. WILL FOLLOW SUIT ON THE HWO AND DROP RISK OF SVR TODAY...BUT WILL LEAVE IN MENTION OF STRONGER STORMS CONTAINING SMALL HAIL AND GUSTY WINDS TO 50 MPH. KEPT LOW CHC POPS GOING FOR THE AFTERNOON ACROSS MUCH OF THE CWA. WED NIGHT AND THU...WILL MAINTAIN LOW CHANCE POPS FOR ANY AFTERNOON CONVECTION THAT MAY LINGER INTO THE EVENING ON TAIL END OF DEPARTING SHORTWAVE...MAINLY FOR CENTRAL AND ERN SECTIONS OF THE CWA. OTHERWISE...EXPECT DRY CONDITIONS INTO THU AS DNVA/RIDGING MOVE IN BEHIND THE SHRTWV. 850MB TEMPS AROUND 14C WILL ALLOW LOCATIONS AWAY FROM THE GREAT LAKES TO CLIMB INTO THE LOW TO MID 80S. COOLER READINGS WILL OCCUR ALONG THE GREAT LAKES SHORELINES AS LAKE BREEZES DEVELOP UNDER WEAK GRADIENT FROM HIGH PRESSURE OVERHEAD. FRI...ANOTHER SHORTWAVE EMERGES FROM THE BRITISH COLUMBIA COAST AND CARVES OUT CLOSED LOW OVER THE HIGH PLAINS BY LATE FRI INTO FRIDAY NIGHT. KEPT HIGHEST POPS FRI AFTERNOON OVER THE WEST HALF AND SPREAD LIKELY POPS ACROSS THE AREA FRI NIGHT AS MODELS SHOW IMPRESSIVE HEIGHT FALLS AHEAD OF THE APPROACHING UPR LOW. SPC STILL INDICATES A SLIGHT RISK FOR SVR STORMS ACROSS MUCH OF OUR AREA FRI AFTERNOON INTO FRI NIGHT WHICH SEEMS REASONABLE GIVEN GFS FCST OF MLCAPES OF 500-1000 J/KG AND 30-40 KT 0-6KM BULK SHEAR. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... VFR CIGS AND VIS REMAIN DESPITE A DISTURBANCE/FRONTAL BOUNDARIES SWEEPING THROUGH THE AREA. MOST OF THE ACTIVITY REMAINS OVER LAKE SUPERIOR...WITH ONLY SHORT TOP CUMULUS POPPING UP OVER LAND THUS FAR. WENT WITH TEMPO SHOWERS AT CMX...WITH A BETTER CHANCE LATE THIS AFTERNOON AT SAW. THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL GREATLY DECREASE ONCE AGAIN WITH THE LOSS OF DAYTIME HEATING AND THE EXITING DISTURBANCE AND THE WEAK COLD FRONT SLIDING EAST OF SAW BY 06Z. THE MAIN DIFFERENCE WITH BE A WESTERLY SHIFT TO THE WINDS AND FEWER CLOUDS FOR THURSDAY. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS/WAVES SHOULD REMAIN FAIRLY LIGHT ACROSS THE LAKE TODAY. THE GENERAL WEATHER PATTERN SUGGESTS WINDS WILL REMAIN SOUTHERLY THROUGH SATURDAY AS HIGH PRESSURE SHIFTS EAST OF LAKE SUPERIOR. SOME BRIEF SHIFTS OF WIND WILL OCCUR ON TODAY WITH ANY SHOWERS DEVELOPMENT...BUT WINDS SHOULD GENERALLY REMAIN 20 KNOTS OR LESS THROUGH REST OF THE PERIOD. AS THE NEXT LOW PASSES THROUGH THE AREA ON SUNDAY WINDS WILL VEER NORTH. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS/DISCUSSION...VOSS AVIATION...KF MARINE...DLG mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 729 AM EDT WED JUN 25 2008 .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS WITH SEVERAL SHORTWAVE TROUGHS OF NOTE. ONE SHRTWV MOVING ACROSS LAKE SUPERIOR SUPPORTED A LINE OF ISOLD SHRA EARLY THIS MORNING STRETCHING WEST TO EAST ACROSS LAKE SUPERIOR ALONG A SFC TROF INTERSECTING THE KEWEENAW PENINSULA. ANOTHER SHORTWAVE OVER SRN MANITOBA WILL BE POISED TO MOVE ACROSS THE UPR GREAT LAKES THIS AFTERNOON AND EVENING BRINGING THE POTENTIAL FOR ISOLD TO SCT SHRA/TSRA. && .DISCUSSION... TODAY...THE SRN SASK SHRTWV WILL MOVE ACROSS THE AREA. MODELS SUGGEST GREATER INSTABILITY WILL DEVELOP AS LOW LEVEL MOISTURE ADVECTS TOWARD THE WRN LAKES FROM IA AND SRN MN. FCST TEMP/DEWPOINTS NEAR 80/60 WOULD INDICATE CAPE VALUES BETWEEN 500-1000 J/KG. IF THIS INSTABILITY IS REALIZED...THERE IS SUFFICIENT DEEP LAYER SHEAR OF 40-50KT TO LEAD TO A FEW ISOLD SVR STORMS. THE BIG QUESTION IS WILL DRIER (MID-UPR 50S) DEWPOINTS MIX TO THE SFC SIMILAR TO WHAT HAPPENED YESTERDAY AND LIMIT AND/OR INHIBIT CONVECTION. LOOKING AT HOW DRY UPSTREAM 00Z SNDGS AT KINL AND KMPX ARE...I CERTAINLY THINK THAT THE NAM AND GFS MODEL DEWPOINTS ARE OVERDONE. IF DRY AIR ALOFT DOES LOWER SFC DEWPOINTS INTO THE MID-UPR 50S...IT WILL HARD TO BREAK THROUGH MID LVL CAP AT 750 MB. SPC MUST ALSO BE THINKING ALONG LINES OF A REDUCED THREAT OR DRIER SOLN AS THEY HAVE DROPPED OUR CWA OUT OF SLIGHT RISK FOR DAY1. WILL FOLLOW SUIT ON THE HWO AND DROP RISK OF SVR TODAY...BUT WILL LEAVE IN MENTION OF STRONGER STORMS CONTAINING SMALL HAIL AND GUSTY WINDS TO 50 MPH. KEPT LOW CHC POPS GOING FOR THE AFTERNOON ACROSS MUCH OF THE CWA. WED NIGHT AND THU...WILL MAINTAIN LOW CHANCE POPS FOR ANY AFTERNOON CONVECTION THAT MAY LINGER INTO THE EVENING ON TAIL END OF DEPARTING SHORTWAVE...MAINLY FOR CENTRAL AND ERN SECTIONS OF THE CWA. OTHERWISE...EXPECT DRY CONDITIONS INTO THU AS DNVA/RIDGING MOVE IN BEHIND THE SHRTWV. 850MB TEMPS AROUND 14C WILL ALLOW LOCATIONS AWAY FROM THE GREAT LAKES TO CLIMB INTO THE LOW TO MID 80S. COOLER READINGS WILL OCCUR ALONG THE GREAT LAKES SHORELINES AS LAKE BREEZES DEVELOP UNDER WEAK GRADIENT FROM HIGH PRESSURE OVERHEAD. FRI...ANOTHER SHORTWAVE EMERGES FROM THE BRITISH COLUMBIA COAST AND CARVES OUT CLOSED LOW OVER THE HIGH PLAINS BY LATE FRI INTO FRIDAY NIGHT. KEPT HIGHEST POPS FRI AFTERNOON OVER THE WEST HALF AND SPREAD LIKELY POPS ACROSS THE AREA FRI NIGHT AS MODELS SHOW IMPRESSIVE HEIGHT FALLS AHEAD OF THE APPROACHING UPR LOW. SPC STILL INDICATES A SLIGHT RISK FOR SVR STORMS ACROSS MUCH OF OUR AREA FRI AFTERNOON INTO FRI NIGHT WHICH SEEMS REASONABLE GIVEN GFS FCST OF MLCAPES OF 500-1000 J/KG AND 30-40 KT 0-6KM BULK SHEAR. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... VFR CIGS AND VIS TO DOMINATE THIS MORNING. A SHORTWAVE TROUGH/DISTURBANCE WILL SWEEP THROUGH THE AREA THIS AFTERNOON RESULTING IN AFTERNOON SHOWERS AND THUNDERSTORMS. HINTED AT THIS AFTER 18Z WITH -SHRA AND CB AS CIGS FALL TO LOWER VFR RANGE. MAY NEED TO CLEARLY MENTION TS IN THE TAFS AS TIME NEARS AND THE POTENTIAL OF AN ACCURATE OCCURRENCE BECOME MORE LIKELY. THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL GREATLY DECREASE ONCE AGAIN WITH THE LOSS OF DAYTIME HEATING AND THE EXITING DISTURBANCE. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS/WAVES SHOULD REMAIN FAIRLY LIGHT ACROSS THE LAKE TODAY. THE GENERAL WEATHER PATTERN SUGGESTS WINDS WILL REMAIN SOUTHERLY THROUGH SATURDAY AS HIGH PRESSURE SHIFTS EAST OF LAKE SUPERIOR. SOME BRIEF SHIFTS OF WIND WILL OCCUR ON TODAY WITH ANY SHOWERS DEVELOPMENT...BUT WINDS SHOULD GENERALLY REMAIN 20 KNOTS OR LESS THROUGH REST OF THE PERIOD. AS THE NEXT LOW PASSES THROUGH THE AREA ON SUNDAY WINDS WILL VEER NORTH. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS/DISCUSSION...VOSS AVIATION...DLG MARINE...DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 530 AM EDT WED JUN 25 2008 .SYNOPSIS (ISSUED AT 420 PM EDT TUE)... WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS WITH SEVERAL SHORTWAVE TROUGHS OF NOTE. ONE SHRTWV MOVING ACROSS LAKE SUPERIOR SUPPORTED A LINE OF ISOLD SHRA EARLY THIS MORNING STRETCHING WEST TO EAST ACROSS LAKE SUPERIOR ALONG A SFC TROF INTERSECTING THE KEWEENAW PENINSULA. ANOTHER SHORTWAVE OVER SRN MANITOBA WILL BE POISED TO MOVE ACROSS THE UPR GREAT LAKES THIS AFTERNOON AND EVENING BRINGING THE POTENTIAL FOR ISOLD TO SCT SHRA/TSRA. && .DISCUSSION... TODAY...THE SRN SASK SHRTWV WILL MOVE ACROSS THE AREA. MODELS SUGGEST GREATER INSTABILITY WILL DEVELOP AS LOW LEVEL MOISTURE ADVECTS TOWARD THE WRN LAKES FROM IA AND SRN MN. FCST TEMP/DEWPOINTS NEAR 80/60 WOULD INDICATE CAPE VALUES BETWEEN 500-1000 J/KG. IF THIS INSTABILITY IS REALIZED...THERE IS SUFFICIENT DEEP LAYER SHEAR OF 40-50KT TO LEAD TO A FEW ISOLD SVR STORMS. THE BIG QUESTION IS WILL DRIER (MID-UPR 50S) DEWPOINTS MIX TO THE SFC SIMILAR TO WHAT HAPPENED YESTERDAY AND LIMIT AND/OR INHIBIT CONVECTION. LOOKING AT HOW DRY UPSTREAM 00Z SNDGS AT KINL AND KMPX ARE...I CERTAINLY THINK THAT THE NAM AND GFS MODEL DEWPOINTS ARE OVERDONE. IF DRY AIR ALOFT DOES LOWER SFC DEWPOINTS INTO THE MID-UPR 50S...IT WILL HARD TO BREAK THROUGH MID LVL CAP AT 750 MB. SPC MUST ALSO BE THINKING ALONG LINES OF A REDUCED THREAT OR DRIER SOLN AS THEY HAVE DROPPED OUR CWA OUT OF SLIGHT RISK FOR DAY1. WILL FOLLOW SUIT ON THE HWO AND DROP RISK OF SVR TODAY...BUT WILL LEAVE IN MENTION OF STRONGER STORMS CONTAINING SMALL HAIL AND GUSTY WINDS TO 50 MPH. KEPT LOW CHC POPS GOING FOR THE AFTERNOON ACROSS MUCH OF THE CWA. WED NIGHT AND THU...WILL MAINTAIN LOW CHANCE POPS FOR ANY AFTERNOON CONVECTION THAT MAY LINGER INTO THE EVENING ON TAIL END OF DEPARTING SHORTWAVE...MAINLY FOR CENTRAL AND ERN SECTIONS OF THE CWA. OTHERWISE...EXPECT DRY CONDITIONS INTO THU AS DNVA/RIDGING MOVE IN BEHIND THE SHRTWV. 850MB TEMPS AROUND 14C WILL ALLOW LOCATIONS AWAY FROM THE GREAT LAKES TO CLIMB INTO THE LOW TO MID 80S. COOLER READINGS WILL OCCUR ALONG THE GREAT LAKES SHORELINES AS LAKE BREEZES DEVELOP UNDER WEAK GRADIENT FROM HIGH PRESSURE OVERHEAD. FRI...ANOTHER SHORTWAVE EMERGES FROM THE BRITISH COLUMBIA COAST AND CARVES OUT CLOSED LOW OVER THE HIGH PLAINS BY LATE FRI INTO FRIDAY NIGHT. KEPT HIGHEST POPS FRI AFTERNOON OVER THE WEST HALF AND SPREAD LIKELY POPS ACROSS THE AREA FRI NIGHT AS MODELS SHOW IMPRESSIVE HEIGHT FALLS AHEAD OF THE APPROACHING UPR LOW. SPC STILL INDICATES A SLIGHT RISK FOR SVR STORMS ACROSS MUCH OF OUR AREA FRI AFTERNOON INTO FRI NIGHT WHICH SEEMS REASONABLE GIVEN GFS FCST OF MLCAPES OF 500-1000 J/KG AND 30-40 KT 0-6KM BULK SHEAR. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... EXPECT VFR CIGS AND VIS TO DOMINATE. THE ONLY FLY IN THE OINTMENT WILL BE A SHORTWAVE TROUGH/DISTURBANCE TUESDAY AFTERNOON. THIS SHOULD RESULT IN AFTERNOON SHOWERS AND THUNDERSTORMS. HINTED AT THIS AFTER 17Z WITH -SHRA AND CB AS CIGS FALL TO LOWER VFR RANGE. MAY NEED TO CLEARLY MENTION TS IN THE TAFS AS TIME NEARS AND THE POTENTIAL OF AN ACCURATE OCCURRENCE BECOME MORE LIKELY. THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL GREATLY DECREASE ONCE AGAIN WITH THE LOSS OF DAYTIME HEATING AND THE EXITING DISTURBANCE. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS/WAVES SHOULD REMAIN FAIRLY LIGHT ACROSS THE LAKE TODAY. THE GENERAL WEATHER PATTERN SUGGESTS WINDS WILL REMAIN SOUTHERLY THROUGH SATURDAY AS HIGH PRESSURE SHIFTS EAST OF LAKE SUPERIOR. SOME BRIEF SHIFTS OF WIND WILL OCCUR ON TODAY WITH ANY SHOWERS DEVELOPMENT...BUT WINDS SHOULD GENERALLY REMAIN 20 KNOTS OR LESS THROUGH REST OF THE PERIOD. AS THE NEXT LOW PASSES THROUGH THE AREA ON SUNDAY WINDS WILL VEER NORTH. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS/DISCUSSION...VOSS AVIATION...KF MARINE...DLG mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 138 AM EDT TUE JUN 24 2008 UPDATED FOR 06Z TAF ISSUANCE .SYNOPSIS (ISSUED AT 412 PM EDT MON)... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM HUDSON BAY INTO THE ERN LAKES...A RIDGE FROM THE SW CONUS INTO THE UPPER MS VALLEY...AND WSW THROUGH THE NW CONUS. A SHORTWAVE TROUGH OVER FROM SRN ALBERTA INTO SW SASK IS EXPECTED TO IMPACT WEATHER OVER THE WRN LAKES TUE. AT THE SFC... HIGH PRES DOMINATED THE WRN GREAT LAKES AS ACYC NRLY FLOW HAS BROUGHT CLEARING OVER MOST OF UPPER MI. CU FIELDS HAVE DEVELOPED INLAND FROM LAKE SUPERIOR WHILE AN AREA OF FOG PERSISTED OVER CNTRL INTO SRN LAKE SUPERIOR. && .SHORT TERM...(TONIGHT AND TUESDAY) TONIGHT...DECENT RADIATIONAL COOLING CONDITIONS SHOULD ALLOW TEMPS TO FALL INTO THE MID AND UPPER 40S...EXCEPT OVER THE WEST WHERE INCREASE IN SRLY WINDS LATE AND POTENTIAL FOR SOME HIGH CLOUDS WILL KEEP READINGS IN THE LOWER 50S. TUESDAY...ALTHOUGH THE STRONGEST FORCING REMAINS MAINLY NORTH OF THE CWA...QG FORCING...UPPER LEVEL DIV WITH JET LEFT EXIT REGION AND 300K-305 ISENTROPIC LIFT AHEAD OF THE SASK SHRTWV MAY BE ENOUGH TO BRING SOME PCPN INTO WRN LAKE SUPERIOR LATE TONIGHT AND INTO W UPPER MI TUE MORNING. DAYTIME HEATING AND LOW LEVEL CONV VCNTY LAKE BREEZE BOUNDARIES AND A WEAK SFC TROUGH SHOULD BE ENOUGH TO TRIGGER SCT AFTERNOON SHRA/TSRA. PROFILE USING HIGHER END SFC TEMP/DEWPOINT VALUES AROUND 77/54 WOULD GIVE MLCAPE VALUES INTO THE 500-1000 J/KG RANGE. 0-6KM BULK SHEAR VALUES TO NEAR 35 KT MAY BE SUFFICIENT FOR SOME STORM ORGANIZATION AND LOW END RISK FOR HAIL TO AROUND A HALF INCH. && .LONG TERM (TUESDAY NIGHT THROUGH DAY 7)... THROUGHOUT THIS TIME PERIOD WE CAN EXPECT ON AND OFF CHANCES FOR PRECIPITATION IN THE FORM OF SHOWERS AND THUNDERSTORMS WITH THE MOST SIGNIFICANT POPS COINCIDING WITH BROAD LOW PRESSURE ENTERING THE CWA THIS WEEKEND. FOR TUESDAY NIGHT DECIDED TO CONFINE POPS MAINLY TO EASTERN AREAS OF THE CWA AS BETTER MOISTURE AND BETTER CONVERGENCE REMAINS GENERALLY OVER THE EAST. AS SHORTWAVE FEATURE EXITS TO THE EAST...OPTED TO REMOVE POPS PAST 06Z WED. BETTER OPPORTUNITY FOR SHOWERS AND THUNDERSTORMS DURING THE DAY ON WEDNESDAY AS MID LEVEL SHORTWAVE COMBINED WITH DAY TIME HEATING WILL ALLOW FOR SHOWER/THUNDERSTORM DEVELOPMENT. A QUICK LOOK AT AREA SOUNDINGS SHOW MODEST CAPE VALUES MAINLY ACROSS THE WEST HALF...ANY SEVERE POTENTIAL WOULD BE CONFINED TO HAIL...THOUGH BE IT SMALL..AS DEEP LAYER SHEAR IN OUR AREA IS WEAK. IN FACT THE WESTERN U.P. IS IN THE SLIGHT RISK OUTLOOK DURING THIS TIME. DRIER AIR WORKS INTO THE FA ON THURSDAY AHEAD OF A BROAD UPPER LEVEL LOW PRESSURE WHICH LOOKS TO DOMINATE U.P. WEATHER THROUGH THE WEEKEND. DID INCREASE POPS A BIT ON FRIDAY AS MODEL GUIDANCE/OUTLOOK FROM SPC INDICATES SVR POTENTIAL IS QUITE GOOD. OPTED TO KEEP CHANCE WORDING FOR NOW...THINK UPCOMING SHIFTS WILL NEED TO INCREASE POPS THROUGH THE WEEKEND. LOOKING TO THE EXTENDED PERIOD...DECIDED TO ADD POPS INTO EARLY SUNDAY MORNING WITH BROAD ASCENT AND MOISTURE REMAINING OVER THE U.P. ALSO TRENDED TEMPERATURES COOLER FOR SATURDAY AND SUNDAY. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... EXPECT VFR CIGS AND VIS TO DOMINATE. THE ONLY FLY IN THE OINTMENT WILL BE A SHORTWAVE TROUGH/DISTURBANCE TUESDAY AFTERNOON. THIS SHOULD RESULT IN AFTERNOON SHOWERS AND THUNDERSTORMS. HINTED AT THIS AFTER 17Z WITH -SHRA AND CB AS CIGS FALL TO LOWER VFR RANGE. MAY NEED TO CLEARLY MENTION TS IN THE TAFS AS TIME NEARS AND THE POTENTIAL OF AN ACCURATE OCCURRENCE BECOME MORE LIKELY. THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL GREATLY DECREASE ONCE AGAIN WITH THE LOSS OF DAYTIME HEATING AND THE EXITING DISTURBANCE. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS/WAVES SHOULD REMAIN FAIRLY LIGHT ACROSS THE LAKE FOR THE NEXT SEVERAL DAYS. THERE ARE SOME MINOR MODEL DIFFERENCES WITH REGARD TO WINDS AFTER TONIGHT...BUT THE GENERAL PATTERN SUGGESTS WINDS WILL TURN SOUTHERLY TONIGHT AND REMAIN THAT WAY THROUGH WED AS HIGH PRES SHIFTS EAST OF LAKE SUPERIOR. MAY SEE SOME BRIEF SHIFTS OF WIND ON TUESDAY AND AGAIN ON WED WITH ANY CONVECTION...BUT WINDS SHOULD GENERALLY REMAIN 15 KT OR LESS THROUGH WED AT LEAST. WIDESPREAD STRATUS AND FOG ARE EXPECTED TO THIS OUT LATE THIS AFTERNOON AND EVENING BUT SOME AREAS MAY PERSIST TONIGHT BEFORE DIMINISHING TUE AS SRLY WINDS INCREASE. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS/SHORT TERM...JLB LONG TERM...PEARSON AVIATION...KF MARINE...JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1151 PM EDT TUE JUN 24 2008 .AVIATION...MID-LEVEL CLOUDS ACROSS THE CENTRAL U.P. HAVE MOSTLY DISSIPATED AND DONT STAND MUCH OF A CHANCE OF REACHING PLN OVERNIGHT. IFR VSBYS HAVE QUICKLY OVERTAKEN APN...AND WITH CLEAR SKIES AND LIGHT WINDS...SUPPOSE LIFR CONDITIONS ARE POSSIBLE DURING THE EARLY TOMORROW MORNING. OTHERWISE...A MID- LEVEL DISTURBANCE OVER THE GREAT PLAINS WILL REACH THE SW GREAT LAKES BY MORNING. CONVERGING WINDS ABOUT A MILE OFF THE SURFACE MAY ALLOW SOME 5-7KFT CLOUDS TO DEVELOP AROUND THE STRAITS...WHICH COULD DEVELOP A SPRINKLE AT PLN...BUT WILL LEAVE OUT OF THE FORECAST FOR NOW SINCE UNCERTAINTY IS FAIRLY HIGH. THE MID- LEVEL DISTURBANCE WILL PUSH A WARM FRONT NORTHEAST TOWARDS THE REGION BY TOMORROW AFTERNOON. SOME LOW-END MID CLOUDS CAN BE EXPECTED AHEAD OF THIS WARM FRONT AT APN AND POSSIBLY TVC...BUT BEST FORCING FOR PRECIP LOOKS TO REMAIN TO YOUR SOUTH AT THIS TIME. A WEAKENING COLD FRONT THEN WILL REACH NORTHERN MICHIGAN LATE TOMORROW EVENING AND COULD GENERATE A SHOWER AT PLN/TVC. WILL MAINTAIN THE VFR FORECAST THROUGH THE TAF PERIOD AT ALL SITES EXCEPT APN. MPC && .PREV DISCUSSION... /ISSUED 945 PM EDT TUE JUN 24 2008/ UPDATE...LATEST RUC ANALYSIS AND IR/WV/RADAR IMAGERY SHOW HEIGHT FALLS OCCURRING NORTH OF LAKE SUPERIOR ASSOCIATED WITH A SHORTWAVE EMBEDDED WITHIN THE WESTERLY FLOW ALOFT. MID-LEVEL FORCING AHEAD OF THIS WAVE HAS BEEN CONFINED TO THE SOUTH SHORE OF LAKE SUPERIOR AND POINTS NORTH. HOWEVER...PLENTY OF DRY/ANTICYCLONIC FLOW IN THE LOW LEVELS COURTESY OF HIGH PRESSURE ANCHORED OVER THE EASTERN GREAT LAKES TO THE SPINE OF THE APPALACHIANS...HAS KEPT ANY SHOWER ACTIVITY AT BAY. BAND OF LOW END MID-LEVEL CLOUDS AHEAD OF A 700MB THETAE GRADIENT OVER THE CENTRAL U.P. IS SLOWLY DISSIPATING WITH LOSS OF DAYTIME HEATING AND IS CONSEQUENTLY HAVING A DIFFICULT TIME REACHING EASTERN UPPER. ALONG THE SAME LINES...OTHER DIURNAL CU OVER PORTIONS OF NE LOWER SHOULD ALSO KICK THE BUCKET SHORTLY. FOR THE REST OF THE NIGHT...AFOREMENTIONED 700MB THETAE GRADIENT WILL LAY OUT ACROSS EASTERN UPPER BY MORNING AND COULD SEE A FEW/SCT MID- LEVEL CLOUDS WORK INTO THE AREA. OTHERWISE...TOUGH TO FIND ANY REASON TO KEEP PARTLY CLOUDY SKIES IN THE FORECAST FOR NORTHERN LOWER UNTIL LATE TONIGHT. THATS WHEN LOW/MID LEVEL WINDS BACK AHEAD OF A SHORTWAVE OVER THE SW GREAT LAKES. THIS CAUSES CONFLUENT FLOW TO DEVELOP AT 850MB WHICH IS THEN CHANNELED TOWARDS THE STRAITS REGION. ALTHOUGH LOW LEVEL DEWPOINT PUSH DOES NOT ENTER OUR AREA UNTIL TOMORROW AFTERNOON...COULD SEE PARTLY CLOUDY SKIES DEVELOP OVER THE NW LOWER MICHIGAN SHORELINE AND EASTERN UPPER AS A RESULT. REST OF THE FORECAST LOOKS SUPER. ZONES OUT SHORTLY. MPC PREV DISCUSSION... /ISSUED 337 PM EDT TUE JUN 24 2008/ DISCUSSION...MID AFTERNOON OBSERVATIONAL AND NUMERICAL GUIDANCE ANALYSIS SHOWS NORTHERN MICHIGAN WEATHER DOMINATED BY LOW LEVEL RIDGE AXIS OVERTOPPED BY NORTHWEST MID AND UPPER LEVEL FLOW. OTHER THAN SOME HIGH CLOUDS AND A FEW FAIR WEATHER CUMULUS...CONDITIONS HAVE BEEN RATHER TRANQUIL WITH ANTICIPATED AFTERNOON MIXING OF REMNANT LOW LEVEL MOISTURE PREVENTING THE FORMATION OF DIURNALLY DRIVEN SHOWERS. LOOKING UPSTREAM...BROAD...NEARLY ZONAL...WEST TO NORTHWEST FLOW PERSISTS OVER THE NORTHERN CONUS/SOUTHERN CANADA WITH SEVERAL WAVES EMBEDDED WITHIN...THE CLOSEST OF WHICH IS PIVOTING EAST NORTH OF THE ARROWHEAD OF MINNESOTA. FORECAST CONCERN TONIGHT ARE RATHER TRIVIAL...CENTERING ON TEMPERATURE/CLOUD TRENDS ALONG WITH ANY SHOWER POTENTIAL. TONIGHT...RATHER UNEVENTFUL NIGHT EXPECTED AS MAIN DYNAMICS OF LEAD SHORTWAVE PUSH NORTH OF THE AREA THIS EVENING...FOLLOWED BY A VERY SUBTLE WAVE PASSING THROUGH THE FAR NORTH LATER TONIGHT. GIVEN UPSTREAM OBSERVATIONS SHOWING A DEARTH OF ACTIVITY ASSOCIATED WITH EITHER...WOULD EXPECT GENERALLY DRY CONDITIONS ACROSS THE BOARD. HOWEVER...MUCH LIKE PREVIOUS FORECASTER MENTIONED...CANNOT ENTIRELY RULE OUT AN ISOLATED SPRINKLE OVER EASTERN UPPER MICHIGAN WITH SOME MID LEVEL MOISTURE POOLING AHEAD OF ENCROACHING WAVES. STILL...CONFIDENCE IS VERY LOW WITH THIS SCENARIO SO HAVE DECIDED TO PULL SPRINKLE MENTION. RATHER MILD NIGHT EXPECTED WITH READINGS ONLY DROPPING INTO THE MID TO UPPER 50S. MSB WEDNESDAY...NEARLY ZONAL UPPER FLOW WILL LINGER OVER THE NORTHERN LAKES REGION THROUGH THE PERIOD...WITH ONLY A WEAK RIPPLE NOTED IN THE FLOW NORTH OF LAKE SUPERIOR. AT THE SURFACE...A DOMINATE AREA OF HIGH PRESSURE WILL BE CENTERED OVER THE ATLANTIC COAST AND ERN LAKES REGION THROUGH THE MORNING...WITH A STORM SYSTEM OVER THE UPPER MIDWEST AND CENTRAL PLAINS. A WARM FRONT LOCATED ACROSS IOWA AND ILL EARLY WED HAS THE POTENTIAL FOR ANOTHER MCS JUST NORTH OF THE BOUNDARY...WERE A 20-25KT LOW LVL JET INTERSECTS THE BOUNDARY AND AN 850MB MSTR TONGUE OF 13C. 850/300 MB THICKNESS PATTERN SHOWS THIS MCS MOVING WELL SOUTH OF THE APX CWA IN THE MORNING...MAYBE GRAZING SW LOWER MICHIGAN IN THE MORNING. HOWEVER FOR THE REST OF THE DAY...THE CENTRAL PLAINS WARM FRONT IS PROGGED TO MOVE INTO LOWER MICHIGAN BY THE AFTERNOON. AN UNSTABLE AIRMASS WILL BE IN PLACE OVER THE STATE IN ADVANCE OF THIS FEATURE. 850MB DEW PTS WILL BE AROUND 12C WITH SFC DEW PTS IN THE UPPER 50S. CORRESPONDING INDICES SHOW A LIFTED INDEX AND SHOWALTER AROUND -3C WITH CAPE VALUES AROUND 800 J/KG. OVERALL WILL MENTION SCATTERED SHOWERS AND THUNDERSTORMS OVER THE FORECAST AREA INTO THE EVENING. WILL ALSO MENTION A CHANCE OF SHOWERS AND THUNDERSTORMS OVER NRN MI WEDNESDAY NIGHT AS AN UNSTABLE AIRMASS LINGERS OVER THE GREAT LAKES AND A COLD FRONT SWEEPS OVER THE STATE. ADDITIONAL LIFT OVERNIGHT WILL BE SUPPLIED BY A WEAK 500 MB WAVE SWEEPING OVER THE NRN LAKES. WILL MENTION AFTERNOON HIGHS IN THE LOWER 80S AS 850 MB TEMPS WARM TO AROUND 14C. OVERNIGHT LOWS WILL REMAIN MILD AND ABOVE NORMAL OVERNIGHT...GENERALLY IN THE LOWER 60S. THURSDAY...850MB DEW PTS WILL REMAIN AROUND 12C OVER NORTHEAST LOWER IN THE MORNING...WITH 850 MB DEW PTS DIMINISHING TO UNDER 8C ACROSS THE ENTIRE NRN LAKES REGION BY THE AFTERNOON AS THE WEAK FRONT PUSHES EAST OF LAKE HURON. SOME CONVECTIVE POTENTIAL LINGERS OVER NE LWR IN THE MORNING...WITH LIFTED AND SHOWALTER INDEX AROUND -2C IN RESPONSE TO 850MB DEW PTS AROUND 12C AND SFC DEW PTS IN THE UPPER 50S. CAPE VALUES WILL BE MINOR ONLY AROUND 600 J/KG IN THE SAGINAW BAY REGION JUST AHEAD OF THE SFC FRONT. THEREFORE WILL LINGER A CHANCE OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST LOWER IN THE MORNING AS THE STORM SYSTEM CONTINUES TO SLOWLY MOVE EAST OF THE GREAT LAKES. WILL MENTION DRY CONDS ACROSS THE REST OF THE FORECAST AREA WITH SOME SUN AND MILD AFTERNOON TEMPERATURES...MAINLY IN THE UPPER 70S AND LOWER 80S. WILL KEEP THE FORECAST AREA DRY THURSDAY NIGHT...AS SURFACE AND UPPER LEVEL RIDGING BUILDS OVER THE GREAT LAKES FROM THE UPPER MIDWEST. WILL KEEP OVERNIGHT LOWS MILD MAINLY IN THE UPPER 50S TO NEAR 60S...DUE TO LINGERING LOW LEVEL MSTR AND WEAK SW FLOW. FRIDAY...THE GREAT LAKES REGION WILL BE BETWEEN SYSTEMS WITH SURFACE AND UPPER LEVEL RIDGING LINGERING OVER THE STATE INTO THE MORNING AND AFTERNOON. THE NEXT STORM SYSTEM TO MOVE INTO THE GREAT LAKES WILL BE LATE FRIDAY AFTN...AS ANOTHER UPPER MIDWEST STORM SYSTEM MOVES INTO THE WRN LAKES AND WRN UPPER MICHIGAN. AT UPPER LEVELS THE GREAT LAKES REGION WILL BE MAINLY DOMINATED BY A STRONG UPPER RIDGE THROUGH THE PERIOD. THE UPPER MIDWEST STORM SYSTEM IS PROGGED TO PUSH A WARM FRONT UP INTO SRN LOWER MICHIGAN FRIDAY AFTERNOON AND EVENING...WITH THE REST OF THE REGION GENERALLY UNDER LINGERING HIGH PRESSURE. HOWEVER WILL MENTION A CHANCE OF AFTERNOON SHOWERS/THUNDERSTORMS OVER THE SRN CWA NEAREST THE WARM FRONT AND WHERE HIGHER 850/SFC DEW PT AIR AND THEREFORE INSTABILITY WILL BE LOCATED. WILL KEEP THE REST OF THE FORECAST AREA DRY UNTIL THE EVENING. FRIDAY NIGHT...AN UPPER LOW MOVES TOWARD THE WRN LAKES WITH A SFC FRONT MOVING OVER THE NRN LAKES. WITH UNSTABLE AIR IN PLACE WILL MENTION SCT SHOWERS/THUNDERSTORMS ACROSS THE ENTIRE FORECAST AREA OVERNIGHT. HIGHS FRIDAY WILL BE IN THE LOW TO MID 80S AS 850 MB TEMPS WARM TO 14C. WILL KEEP OVERNIGHT LOWS IN THE 50S/60S DUE TO LINGERING HIGH SFC DEW PTS. SATURDAY THROUGH TUESDAY...SATURDAY THROUGH MONDAY IS SHAPING UP TO BE DOMINATED BY AN UPPER LOW OVER THE GREAT LAKES...WITH A SFC LOW MOVING OVER THE NRN LAKES. AN UPPER LOW WILL MOVE INTO WRN LAKE SUPERIOR SATURDAY BEFORE MOVING INTO ERN ONTARIO MONDAY. AT THE SFC...A STORM SYSTEM WILL MOVE INTO THE REGION JUST NORTH OF LAKE SUPERIOR SLOWLY MOVING EAST INTO QUEBEC MONDAY. OVERALL WILL CONTINUE A CHANCE MENTION OF SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND AND INTO MONDAY. WILL KEEP THE FORECAST AREA DRY TUESDAY AS SFC AND UPPER LEVEL RIDGING BUILDS BACK INTO THE GREAT LAKES REGION. HIGH TEMPERATURES WILL BE MILD IN THE 80S SATURDAY BUT WILL COOL INTO THE 70S ON SUNDAY AND MONDAY AS 850 MB TEMPS DROP TO UNDER 10C. WILL WARM TEMPS BACK INTO THE 80S TUESDAY...AS 850 MB TEMPS RECOVER TO AROUND 14C. SWR && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. LS...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 945 PM EDT TUE JUN 24 2008 .UPDATE...LATEST RUC ANALYSIS AND IR/WV/RADAR IMAGERY SHOW HEIGHT FALLS OCCURRING NORTH OF LAKE SUPERIOR ASSOCIATED WITH A SHORTWAVE EMBEDDED WITHIN THE WESTERLY FLOW ALOFT. MID-LEVEL FORCING AHEAD OF THIS WAVE HAS BEEN CONFINED TO THE SOUTH SHORE OF LAKE SUPERIOR AND POINTS NORTH. HOWEVER...PLENTY OF DRY/ANTICYCLONIC FLOW IN THE LOW LEVELS COURTESY OF HIGH PRESSURE ANCHORED OVER THE EASTERN GREAT LAKES TO THE SPINE OF THE APPALACHIANS...HAS KEPT ANY SHOWER ACTIVITY AT BAY. BAND OF LOW END MID-LEVEL CLOUDS AHEAD OF A 700MB THETAE GRADIENT OVER THE CENTRAL U.P. IS SLOWLY DISSIPATING WITH LOSS OF DAYTIME HEATING AND IS CONSEQUENTLY HAVING A DIFFICULT TIME REACHING EASTERN UPPER. ALONG THE SAME LINES...OTHER DIURNAL CU OVER PORTIONS OF NE LOWER SHOULD ALSO KICK THE BUCKET SHORTLY. FOR THE REST OF THE NIGHT...AFOREMENTIONED 700MB THETAE GRADIENT WILL LAY OUT ACROSS EASTERN UPPER BY MORNING AND COULD SEE A FEW/SCT MID- LEVEL CLOUDS WORK INTO THE AREA. OTHERWISE...TOUGH TO FIND ANY REASON TO KEEP PARTLY CLOUDY SKIES IN THE FORECAST FOR NORTHERN LOWER UNTIL LATE TONIGHT. THATS WHEN LOW/MID LEVEL WINDS BACK AHEAD OF A SHORTWAVE OVER THE SW GREAT LAKES. THIS CAUSES CONFLUENT FLOW TO DEVELOP AT 850MB WHICH IS THEN CHANNELED TOWARDS THE STRAITS REGION. ALTHOUGH LOW LEVEL DEWPOINT PUSH DOES NOT ENTER OUR AREA UNTIL TOMORROW AFTERNOON...COULD SEE PARTLY CLOUDY SKIES DEVELOP OVER THE NW LOWER MICHIGAN SHORELINE AND EASTERN UPPER AS A RESULT. REST OF THE FORECAST LOOKS SUPER. ZONES OUT SHORTLY. MPC && .PREV DISCUSSION... /ISSUED 703 PM EDT TUE JUN 24 2008/ AVIATION...SURFACE HIGH PRESSURE RIDGE AXIS SHIFTS EAST TONIGHT...AS A COOL FRONT LAYS OUT ACROSS LAKE SUPERIOR. NO THREAT OF ANY PRECIP WITH THE COOL FRONT SINCE ITS JUST TOO FAR NORTH. THAT LEAVES OCCASIONAL HIGH CLOUDS DRIFTING OVERHEAD DURING THE NIGHT. A MID-LEVEL DISTURBANCE OVER THE GREAT PLAINS WILL MOVE OVER THE SOUTHERN GREAT LAKES...AND PUSH A WARM FRONT NORTHEAST TOWARDS THE REGION BY TOMORROW AFTERNOON. SOME LOW-END MID CLOUDS CAN BE EXPECTED AHEAD OF THIS WARM FRONT AT APN AND POSSIBLY TVC...BUT BEST FORCING FOR PRECIP LOOKS TO REMAIN TO YOUR SOUTH AT THIS TIME. WILL MAINTAIN THE VFR CONDITIONS THROUGH THE TAF PERIOD. MPC PREV DISCUSSION... /ISSUED 337 PM EDT TUE JUN 24 2008/ DISCUSSION...MID AFTERNOON OBSERVATIONAL AND NUMERICAL GUIDANCE ANALYSIS SHOWS NORTHERN MICHIGAN WEATHER DOMINATED BY LOW LEVEL RIDGE AXIS OVERTOPPED BY NORTHWEST MID AND UPPER LEVEL FLOW. OTHER THAN SOME HIGH CLOUDS AND A FEW FAIR WEATHER CUMULUS...CONDITIONS HAVE BEEN RATHER TRANQUIL WITH ANTICIPATED AFTERNOON MIXING OF REMNANT LOW LEVEL MOISTURE PREVENTING THE FORMATION OF DIURNALLY DRIVEN SHOWERS. LOOKING UPSTREAM...BROAD...NEARLY ZONAL...WEST TO NORTHWEST FLOW PERSISTS OVER THE NORTHERN CONUS/SOUTHERN CANADA WITH SEVERAL WAVES EMBEDDED WITHIN...THE CLOSEST OF WHICH IS PIVOTING EAST NORTH OF THE ARROWHEAD OF MINNESOTA. FORECAST CONCERN TONIGHT ARE RATHER TRIVIAL...CENTERING ON TEMPERATURE/CLOUD TRENDS ALONG WITH ANY SHOWER POTENTIAL. TONIGHT...RATHER UNEVENTFUL NIGHT EXPECTED AS MAIN DYNAMICS OF LEAD SHORTWAVE PUSH NORTH OF THE AREA THIS EVENING...FOLLOWED BY A VERY SUBTLE WAVE PASSING THROUGH THE FAR NORTH LATER TONIGHT. GIVEN UPSTREAM OBSERVATIONS SHOWING A DEARTH OF ACTIVITY ASSOCIATED WITH EITHER...WOULD EXPECT GENERALLY DRY CONDITIONS ACROSS THE BOARD. HOWEVER...MUCH LIKE PREVIOUS FORECASTER MENTIONED...CANNOT ENTIRELY RULE OUT AN ISOLATED SPRINKLE OVER EASTERN UPPER MICHIGAN WITH SOME MID LEVEL MOISTURE POOLING AHEAD OF ENCROACHING WAVES. STILL...CONFIDENCE IS VERY LOW WITH THIS SCENARIO SO HAVE DECIDED TO PULL SPRINKLE MENTION. RATHER MILD NIGHT EXPECTED WITH READINGS ONLY DROPPING INTO THE MID TO UPPER 50S. MSB WEDNESDAY...NEARLY ZONAL UPPER FLOW WILL LINGER OVER THE NORTHERN LAKES REGION THROUGH THE PERIOD...WITH ONLY A WEAK RIPPLE NOTED IN THE FLOW NORTH OF LAKE SUPERIOR. AT THE SURFACE...A DOMINATE AREA OF HIGH PRESSURE WILL BE CENTERED OVER THE ATLANTIC COAST AND ERN LAKES REGION THROUGH THE MORNING...WITH A STORM SYSTEM OVER THE UPPER MIDWEST AND CENTRAL PLAINS. A WARM FRONT LOCATED ACROSS IOWA AND ILL EARLY WED HAS THE POTENTIAL FOR ANOTHER MCS JUST NORTH OF THE BOUNDARY...WERE A 20-25KT LOW LVL JET INTERSECTS THE BOUNDARY AND AN 850MB MSTR TONGUE OF 13C. 850/300 MB THICKNESS PATTERN SHOWS THIS MCS MOVING WELL SOUTH OF THE APX CWA IN THE MORNING...MAYBE GRAZING SW LOWER MICHIGAN IN THE MORNING. HOWEVER FOR THE REST OF THE DAY...THE CENTRAL PLAINS WARM FRONT IS PROGGED TO MOVE INTO LOWER MICHIGAN BY THE AFTERNOON. AN UNSTABLE AIRMASS WILL BE IN PLACE OVER THE STATE IN ADVANCE OF THIS FEATURE. 850MB DEW PTS WILL BE AROUND 12C WITH SFC DEW PTS IN THE UPPER 50S. CORRESPONDING INDICES SHOW A LIFTED INDEX AND SHOWALTER AROUND -3C WITH CAPE VALUES AROUND 800 J/KG. OVERALL WILL MENTION SCATTERED SHOWERS AND THUNDERSTORMS OVER THE FORECAST AREA INTO THE EVENING. WILL ALSO MENTION A CHANCE OF SHOWERS AND THUNDERSTORMS OVER NRN MI WEDNESDAY NIGHT AS AN UNSTABLE AIRMASS LINGERS OVER THE GREAT LAKES AND A COLD FRONT SWEEPS OVER THE STATE. ADDITIONAL LIFT OVERNIGHT WILL BE SUPPLIED BY A WEAK 500 MB WAVE SWEEPING OVER THE NRN LAKES. WILL MENTION AFTERNOON HIGHS IN THE LOWER 80S AS 850 MB TEMPS WARM TO AROUND 14C. OVERNIGHT LOWS WILL REMAIN MILD AND ABOVE NORMAL OVERNIGHT...GENERALLY IN THE LOWER 60S. THURSDAY...850MB DEW PTS WILL REMAIN AROUND 12C OVER NORTHEAST LOWER IN THE MORNING...WITH 850 MB DEW PTS DIMINISHING TO UNDER 8C ACROSS THE ENTIRE NRN LAKES REGION BY THE AFTERNOON AS THE WEAK FRONT PUSHES EAST OF LAKE HURON. SOME CONVECTIVE POTENTIAL LINGERS OVER NE LWR IN THE MORNING...WITH LIFTED AND SHOWALTER INDEX AROUND -2C IN RESPONSE TO 850MB DEW PTS AROUND 12C AND SFC DEW PTS IN THE UPPER 50S. CAPE VALUES WILL BE MINOR ONLY AROUND 600 J/KG IN THE SAGINAW BAY REGION JUST AHEAD OF THE SFC FRONT. THEREFORE WILL LINGER A CHANCE OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST LOWER IN THE MORNING AS THE STORM SYSTEM CONTINUES TO SLOWLY MOVE EAST OF THE GREAT LAKES. WILL MENTION DRY CONDS ACROSS THE REST OF THE FORECAST AREA WITH SOME SUN AND MILD AFTERNOON TEMPERATURES...MAINLY IN THE UPPER 70S AND LOWER 80S. WILL KEEP THE FORECAST AREA DRY THURSDAY NIGHT...AS SURFACE AND UPPER LEVEL RIDGING BUILDS OVER THE GREAT LAKES FROM THE UPPER MIDWEST. WILL KEEP OVERNIGHT LOWS MILD MAINLY IN THE UPPER 50S TO NEAR 60S...DUE TO LINGERING LOW LEVEL MSTR AND WEAK SW FLOW. FRIDAY...THE GREAT LAKES REGION WILL BE BETWEEN SYSTEMS WITH SURFACE AND UPPER LEVEL RIDGING LINGERING OVER THE STATE INTO THE MORNING AND AFTERNOON. THE NEXT STORM SYSTEM TO MOVE INTO THE GREAT LAKES WILL BE LATE FRIDAY AFTN...AS ANOTHER UPPER MIDWEST STORM SYSTEM MOVES INTO THE WRN LAKES AND WRN UPPER MICHIGAN. AT UPPER LEVELS THE GREAT LAKES REGION WILL BE MAINLY DOMINATED BY A STRONG UPPER RIDGE THROUGH THE PERIOD. THE UPPER MIDWEST STORM SYSTEM IS PROGGED TO PUSH A WARM FRONT UP INTO SRN LOWER MICHIGAN FRIDAY AFTERNOON AND EVENING...WITH THE REST OF THE REGION GENERALLY UNDER LINGERING HIGH PRESSURE. HOWEVER WILL MENTION A CHANCE OF AFTERNOON SHOWERS/THUNDERSTORMS OVER THE SRN CWA NEAREST THE WARM FRONT AND WHERE HIGHER 850/SFC DEW PT AIR AND THEREFORE INSTABILITY WILL BE LOCATED. WILL KEEP THE REST OF THE FORECAST AREA DRY UNTIL THE EVENING. FRIDAY NIGHT...AN UPPER LOW MOVES TOWARD THE WRN LAKES WITH A SFC FRONT MOVING OVER THE NRN LAKES. WITH UNSTABLE AIR IN PLACE WILL MENTION SCT SHOWERS/THUNDERSTORMS ACROSS THE ENTIRE FORECAST AREA OVERNIGHT. HIGHS FRIDAY WILL BE IN THE LOW TO MID 80S AS 850 MB TEMPS WARM TO 14C. WILL KEEP OVERNIGHT LOWS IN THE 50S/60S DUE TO LINGERING HIGH SFC DEW PTS. SATURDAY THROUGH TUESDAY...SATURDAY THROUGH MONDAY IS SHAPING UP TO BE DOMINATED BY AN UPPER LOW OVER THE GREAT LAKES...WITH A SFC LOW MOVING OVER THE NRN LAKES. AN UPPER LOW WILL MOVE INTO WRN LAKE SUPERIOR SATURDAY BEFORE MOVING INTO ERN ONTARIO MONDAY. AT THE SFC...A STORM SYSTEM WILL MOVE INTO THE REGION JUST NORTH OF LAKE SUPERIOR SLOWLY MOVING EAST INTO QUEBEC MONDAY. OVERALL WILL CONTINUE A CHANCE MENTION OF SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND AND INTO MONDAY. WILL KEEP THE FORECAST AREA DRY TUESDAY AS SFC AND UPPER LEVEL RIDGING BUILDS BACK INTO THE GREAT LAKES REGION. HIGH TEMPERATURES WILL BE MILD IN THE 80S SATURDAY BUT WILL COOL INTO THE 70S ON SUNDAY AND MONDAY AS 850 MB TEMPS DROP TO UNDER 10C. WILL WARM TEMPS BACK INTO THE 80S TUESDAY...AS 850 MB TEMPS RECOVER TO AROUND 14C. SWR && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. LS...NONE. && $$ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 740 PM EDT TUE JUN 24 2008 UPDATED FOR 00Z TAF ISSUANCE .SYNOPSIS (ISSUED AT 420 PM EDT TUE)... WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS WITH SEVERAL EMBEDDED SHORTWAVE TROUGHS. ONE SHRTWV JUST NORTH OF THUNDER BAY ONTARIO STILL SUPPORTED AN AREA OF SHRA/TSRA NORTH OF LAKE SUPERIOR WITH ONLY LIGHT SPRINKLES TO THE SOUTH INTO NRN LAKE SUPERIOR. THE NEXT WELL-DEFINED UPSTREAM SHRTWV WAS LOCATED OVER SW SASK. AT THE SFC...SW FLOW PREVAILED THROUGH WI AND UPPER MI AHEAD OF A WEAK TROUGH INTO NE MN. VIS LOOP SHOWED AN EXTENSIVE CU FIELD OVER THE REGION EXCEPT DOWNWIND FROM THE STABILIZING INFLUENCE OF LAKE MI. FAIRLY DEEP MIXING DEPTH TO NEAR 725 MB HAS DROPPED DEWPOINTS INTO THE UPPER 40S AND REDUCED MLCAPE VALUES AOB 300 J/KG...PER AREA TAMDAR SOUNDINGS. THE LACK OF INSTABILITY AND REMAINING 700-600 MB CAP HAS KEPT ANY SHRA/TSRA FROM DEVELOPING SO FAR. && .SHORT TERM (TONIGHT AND WEDNESDAY)... EVEN THOUGH INSTABILITY AND LIFT ASSOCIATED WITH THE TAIL END OF THE ONTARIO SHRTWV REMAIN MARGINAL TO REDUCE CAPPING AND TRIGGER CONVECTION...ISOLD SHRA/TSRA CANNOT BE RULED OUT AS THE SFC TROUGH MOVES THROUGH. HOWEVER...REDUCED POPS TO BLO 20 PCT. SW WINDS WILL KEEP ENOUGH MIXING GOING TO KEEP MIN TEMPS FROM DROPPING MUCH BLO 60F. WED...THE SASK SHRTWV IS EXPECTED TO MOVE INTO THE AREA. SINCE MODELS SUGGEST GREATER INSTABILITY WILL DEVELOP AS LOW LEVEL MOISTURE ADVECTS TOWARD THE WRN LAKES FROM WRN IA. TEMP/DEWPOINTS NEAR 80/60 GIVING CAPE VALUES AOA 1000 J/KG COMBINED WITH WITH 0-6KM BULK SHEAR VALUES AROUND 40KT SHOULD AGAIN LEAD TO POTENTIAL FOR SCT SHRA/TSRA AND CONDITIONAL SVR WEATHER THREAT FOR ISOLD HAIL AND/OR DAMAGING WINDS...PER SPC OUTLOOK. .LONG TERM (WED NIGHT THROUGH NEXT TUE)... WED NIGHT AND THU...WILL MAINTAIN SOME CHANCE POPS FOR ANY AFTERNOON CONVECTION THAT LINGERS INTO THE EVENING. THESE CHANCE POPS ARE HIGHEST IN THE EASTERN U.P. WHERE THE DPVA FROM THE SHRTWV MOVING ACROSS FAR NORTHERN LAKE SUPERIOR INTERSECTS THE SURFACE TROUGH CROSSING UPPER MI. IF TSRA DO NOT DEVELOP ON WED...THEN THESE POPS CAN BE REMOVED. OTHERWISE...THIS PERIOD LOOKS DRY AS THE AREA SITS IN DNVA BEHIND THE SHRTWV THAT CROSSES NORTHERN LAKE SUPERIOR THU NIGHT AND HIGH PRESSURE AT THE SURFACE. THE NAM DOES TRY TO DEVELOP PCPN IN THE CENTRAL U.P. THU AFTERNOON WITH LAKE BREEZE CONVERGENCE...BUT THE FORECAST DEWPOINTS OF MID 60S IN THE MODEL SEEM TOO HIGH. PREFER THE DRIER MET AND MAV GUIDANCE...AND ESPECIALLY THE GFS WHICH HAS A SOUNDING FOR IMT AT 18Z INDICATIVE OF NOT A CLOUD IN THE SKY. ON THAT NOTE...REDUCED CLOUD COVER...WHICH SHOULD ALLOW FOR DEEP MIXING TO OCCUR ON THU. 850MB TEMPS AROUND 14C WILL ALLOW LOCATIONS AWAY FROM THE GREAT LAKES (PLENTY OF LAKE BREEZES EXPECTED DUE TO HIGH PRESSURE OVER THE AREA) TO CLIMB INTO THE LOW TO PERHAPS MID 80S. THIS ALSO RESULTS IN LOWERING THE DEWPOINTS A FEW DEGREES BELOW LOWEST GUIDANCE AS WELL. FURTHER LOWERING OF DEWPOINTS MAY BE REQUIRED. THU NIGHT AND FRI...UPPER LOW CURRENTLY SITTING ALONG THE MID BRITISH COLUMBIA COAST WILL BECOME THE MAIN FEATURE OF INTEREST... PARTICULARLY FOR FRI INTO THE WEEKEND. AROUND 00Z FRI...MODELS SHOW THE UPPER LOW IN SOUTHERN ALBERTA. AS THIS UPPER LOW BEGINS DIVING DOWN INTO SOUTH CENTRAL CANADA AND THE NORTHERN PLAINS DURING THE PERIOD...A LOW PRESSURE SYSTEM DEVELOPS OUT IN THE PLAINS. WARM ADVECTION DOWNSTREAM OF THIS SYSTEM WILL CAUSE THE TROUGH THAT CROSSED OUR AREA WED NIGHT AND LOCATED DOWN NEAR I-80 THU EVENING TO WORK BACK NORTH. SOME CONVECTION MAY DEVELOP ALONG THIS FRONTAL BOUNDARY...AS INDICATED IN THE 12Z ECMWF/GFS. HOWEVER...BOTH MODELS...IN ADDITION TO THE UKMET AND NAM HOLD ANY WARM ADVECTION STORMS FROM MOVING INTO THE CWA UNTIL FRI. THIS IS DUE TO LINGERING DRY AIR OVER THE CWA THU NIGHT...WHICH WITH NW WINDS OFF EASTERN LAKE SUPERIOR RESULTED IN A LOWERING OF MIN TEMPS IN THE EASTERN CWA (DID NOT GO AS LOW AS THE MET GUIDANCE...THOUGH). HAVE POPS ACROSS THE WEST AND SOUTH CENTRAL PORTIONS OF THE CWA FRI MORNING AND THE ENTIRE CWA FRI AFTERNOON. THE POPS IN THE MORNING ARE FOR THE WARM ADVECTION PCPN MOVING NORTH...WHICH SHOULD WEAKEN DUE TO A WEAKENING OF THE LOW LEVEL JET CAUSED BY DIURNAL MIXING AND AS THE PCPN MOVES INTO THE DRY AIRMASS OVER THE CWA. THE POPS IN THE AFTERNOON...WHICH MAY BE MORE SIGNIFICANT IN TERMS OF THE CONVECTION...ARE DUE TO FALLING HEIGHTS AHEAD OF THE APPROACHING UPPER LOW AND DAYTIME HEATING PRODUCING INSTABILITY. HIGHEST POPS...AROUND 50...ARE CONFINED TO THE WEST HALF OF THE CWA. SPC DELINEATES THE AREA FOR POSSIBLE SVR WX...WHICH LOOKS GOOD BASED ON THE LATEST ECMWF/GFS (1000-1500 J/KG MLCAPE AND 30-40 KT 0-6KM BULK SHEAR). SVR WX WILL LIKELY LAST INTO FRI NIGHT AS THE UPPER LOW NEARS...CAUSING FORCING TO INCREASE. DETAILS ON SVR WX SHOULD BECOME MORE DISCERNIBLE AS FRI GETS CLOSER. FRI NIGHT THROUGH TUE...MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE UPPER LEVEL PATTERN...BASICALLY KEEPING UPPER MI UNDER UPPER LEVEL TROUGHING IN THE MEAN. FIRST UPPER TROUGH...THE ONE MOVING THROUGH SOUTHERN CANADA AND THE NORTHERN PLAINS ON FRIDAY...DIGS INTO UPPER MI ON SAT AND FORMS INTO AN UPPER LOW. CLIMATOLOGICALLY SPEAKING... UPPER LOWS ARE SLOW TO MOVE...AND THE GFS/ECMWF SHOW THIS WELL BY ONLY SHIFTING THE UPPER LOW TO JUST EAST OF SAULT STE MARIE BY 00Z MON. WHILE THIS UPPER LOW IS SHIFTING EASTWARD...ANOTHER UPPER LOW IS PROGGED TO MOVE ACROSS CENTRAL CANADA. THIS NEXT UPPER LOW WILL TRY TO DIG SOUTHEAST INTO UPPER MI AS IT FEELS THE INFLUENCE OF THE OTHER UPPER LOW IN SE CANADA. HOWEVER...THE ECMWF/GFS SEEM TO SUGGEST IT WILL NOT ARRIVE UNTIL WED AT THE EARLIEST...DUE TO AN UPPER LEVEL RIDGE BETWEEN THE TWO UPPER LOWS THAT NEEDS TO BE BROKEN DOWN FIRST. REGARDING PCPN CHANCES...WILL NEED TO HAVE POPS IN FOR ALL OF THE WEEKEND WITH THE UPPER LOW MOVING IN. ALTHOUGH THERE ARE HINTS IN THE 00Z ECMWF OF A DRY SLOT WORKING IN BEHIND THE CONVECTION FRI NIGHT...COLD MID-LEVEL TEMPS WITH THE UPPER LOW COMBINED WITH DAYTIME HEATING ON SATURDAY SHOULD RESULT IN THE DEVELOPMENT OF SCATTERED SHRA AND TSRA. IN ADDITION TO PCPN...SUNDAY LOOKS TO BE COOL AND BREEZY AS THE AREA GETS ON THE BACK SIDE OF THE SURFACE LOW ASSOCIATED WITH THE UPPER LEVEL LOW...AND 850MB TEMPS DROP TO 7-9C. ALTHOUGH ECMWF PAINTS SUNDAY NIGHT AS DRY...THE PROXIMITY TO THE UPPER LOW AND THE GFS SHOWING SOME PCPN MOVING THROUGH RESULTS IN KEEPING SOME LOW CHANCE POPS GOING. CONDITIONS WILL DRY AND WARM UP ON MONDAY AS THE UPPER LOW PULLS AWAY AND SURFACE/UPPER RIDGING BUILD IN. 850MB TEMPS CLIMB NICELY OUT IN THE WEST...WITH READINGS REACHING 15C BY 00Z...AND THEREFORE WARMEST READINGS DEPICTED THERE. STRONGER WARM ADVECTION DEVELOPS MONDAY NIGHT AS 15-18C 850MB TEMPS MOVE IN FOR TUE. SINCE WARM ADVECTION AT NIGHT USUALLY PRODUCES SOME SORT OF PCPN...HAVE INCLUDED 20 POPS ACROSS THE CWA. THE ECMWF DOES NOT SHOW THIS...BUT THE GFS DOES...ENOUGH TOO TO WARRANT THE 20 POPS. LEFT TUE DRY FOR NOW AS ANY WARM ADVECTION PCPN SHOULD SHIFT EAST INTO ONTARIO. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... EXPECT VFR CONDITIONS TO PREVAIL THROUGH THE FORECAST PERIOD. A SCATTED LINE OF LIGHT SHOWERS STRETCHED FROM CENTRAL MARQUETTE COUNTY NORTHEAST THROUGH LAKE SUPERIOR AT 23Z. THIS SHOULD SLIDE NORTH OF SAW BY 01Z...WITH CLOUDS DISSIPATING THEREAFTER. ANOTHER WAVE OF ENERGY IS EXPECTED WEDNESDAY AFTERNOON...WITH BORDERLINE LOW VFR/HIGH MVFR CIGS AFTER 18Z AT BOTH SITES. WILL CONTINUE WITH THE LOW PROBABILITY/LOW CONFIDENCE FORECAST AND KEEP THE MENTION OF THUNDERSTORMS OR CB OUT. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS/WAVES SHOULD REMAIN FAIRLY LIGHT ACROSS THE LAKE FOR THE NEXT SEVERAL DAYS. MODELS SUGGEST THAT WINDS WILL GENERALLY REMAIN SRLY THROUGH WED AS HIGH PRES SHIFTS EAST OF LAKE SUPERIOR. WINDS SHOULD SHIFT AROUND WEST OR NORTHWEST WED NIGHT INTO THU AS A TROUGH MOVES ACROSS THE AREA. WINDS WILL BACK SOUTHEAST OR EAST ON FRI AS ANOTHER LOW PRES TROUGH APPROACHES FROM THE NORTHERN PLAINS. ANOTHER WIND SHIFT TO WRLY IS EXPECTED FRI NIGHT INTO SAT AS THE SECOND TROUGH PASSES ACROSS THE AREA. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS/SHORT TERM...JLB LONG TERM...AJ AVIATION...KF MARINE...JLB mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 200 PM EDT TUE JUN 24 2008 UPDATED FOR 18Z AVIATION DISCUSSION .UPDATE... WV IMAGERY INDICATED A WELL-DEFINED SHORTWAVE TROUGH IN NW ONTARIO JUST NORTH OF KINL/KELO. SOME CONVECTION HAD ALREADY DEVELOPED WEST OF CYQT WITH THE BEST FORCING AND STEEPEST MID LEVEL LAPSE RATES NEAR 7 C/KM. OTHERWISE...LIGHT PCPN SPRINKLES/VIRGA OVER WESTERN LAKE SUPERIOR INTO W UPPER MI WERE DIMINISHING. VIS LOOP ALSO SHOWED CLOUDS SUPPORTED BY 305K-310K ISENTROPIC LIFT WERE ALSO THINNING OUT ACROSS UPPER MI ENOUGH TO ALLOW TEMPS TO CLIMB INTO THE LOWER 60S. MODIFIED FCST SOUNDINGS WITH MIXED LAYER REFLECTING TEMPS IN THE UPPER 70S AND AND DEWPOINTS IN THE LOWER 50S WOULD GIVE CAPE VALUES INTO THE 400-800 J/KG RANGE. ALTHOUGH THE STRONGEST QG FORCING AND UPPER LEVEL DIV WITH THE LEFT EXIT OF THE 80 KT 250 MB JET STREAK INTO NRN MN REMAINS NORTH OF THE CWA...EXPECT ISOLD/SCT COVERAGE OF SHRA/TSRA TO DEVELOP BY MID TO LATE AFTERNOON AS THE SHORTWAVE BRUSHES THE AREA. SOME UNCERTAINTY REMAINS ON THE AMOUNT OF INSTABILITY THAT MAY DEVELOP AS LOCAL HIGH RES WRF SOUNDINGS SUGGEST DEEP ENOUGH MIXING COULD PUSH MOISTURE VALUES LOW ENOUGH TO SIGNIFICANTLY REDUCE TSRA POTENTIAL. 0-6KM BULK SHEAR VALUES TO AROUND 40 KT COULD SUPPORT STORM ORGANIZATION FOR POSSIBILITY OF SEVERE HAIL OR ISOLD DAMAGING WIND GUSTS IF ANY STRONGER STORMS DEVELOP...PER SPC OUTLOOK. && .DISCUSSION... WATER VAPOR IMAGERY AND RUC SHOWING A TROUGH OVER QUEBEC AND A NEAR ZONAL FLOW ACROSS NORTHERN CONUS. WEAK SHORTWAVE TRAVELING ALONG THIS FLOW IS OVER SOUTHEAST MANITOBA EXTENDING INTO THE ARROWHEAD OF MINNESOTA THROUGH WESTERN WISCONSIN. OTHER SHORTWAVES ARE OVER SOUTHERN ALBERTA AND EASTERN WASHINGTON. SURFACE ANALYSIS DEPICTS A LARGE HIGH OVER THE UPPER GREAT LAKES AND THE OHIO RIVER VALLEY. A FRONTAL SYSTEM STRETCHES FROM SOUTH CAROLINA ACROSS THE SOUTHEASTERN STATES THEN INTO THE CENTRAL AND NORTHERN PLAINS. THE QUEBEC TROUGH WILL MOVE INTO THE CANADIAN MARITIME TODAY. THE SURFACE HIGH WILL START TO MOVE TO LOWER GREAT LAKES. 00Z UPWIND SOUNDINGS SHOWING A LAYER AROUND 750MB AND VERY DRY BELOW. NAM/GFS FORECAST SOUNDING SHOWING THIS WILL PREVAILS AS THE AIR MASSES MOVE THROUGH THE FORECAST AREA TODAY. THE MANITOBA AND MINNESOTA SHORTWAVE WILL TRACK ACROSS THE U.P. AS ANOTHER MOVES INTO NORTHEAST MINNESOTA. 300K ISENTROPIC ANALYSIS DEPICTS AN AREA OF ASCENT SLIDING INTO THE WESTERN U.P. BY LATE MORNING AND MOVE THROUGH THE AREA DURING THE AFTERNOON. THE FORECAST SOUNDINGS SUGGEST THAT VIRGA WILL FALL OVER THE AREA...BUT IT WILL NEED TO SATURATE THE DRY LOW LAYER BEFORE RAIN WILL OCCUR. THERE IS ENOUGH LOW LEVEL SHEAR AND LI`S AND INSTABILITY THAT CONVECTIVE WIND OUTFLOW AND LARGE HAIL COULD NOT BE RULED OUT. THUS LOW POPS CONTINUE TO BE IN ORDER. WITH WARM AIR ADVECTING INTO THE AREA FROM THE SOUTHWEST ON THE BACKSIDE OF THE HIGH...TEMPERATURES SHOULD BE A FEW DEGREES WARMER THAN MONDAY. A WEAK SHORTWAVE WILL RACE THROUGH THE AREA TONIGHT AS THE SURFACE HIGH SETTLES INTO THE EASTERN OHIO RIVER VALLEY. A SURFACE LOW WILL DEVELOPING OVER THE CENTRAL ONTARIO WILL TRACK TO THE SOUTH END OF JAMES BY 12Z WEDNESDAY. A LOW CENTER OVER THE CENTRAL PLAINS WILL EDGE INTO NORTHERN MINNESOTA. THE NOSE OF UPPER LEVEL JET MAX WILL RACE ACROSS THE FORECAST AREA EARLY THIS EVENING. THUS WILL KEEP A CHANCE ACROSS THE AREA THIS EVENING. AS DRIER...MORE STABLE AIR ENTERS THE AREA...WILL REDUCE THE CHANGES. ZONAL FLOW WILL CONTINUE ACROSS NORTHERN CONUS. A WEAK SHORTWAVE WILL SWEEP THROUGH THE AREA ON WEDNESDAY. THE UPPER LEVEL JET MAX WILL BE JUST NORTH OF THE AREA. LOW LEVEL MOISTURE WILL BE ENOUGH TO FEED SHOWERS AND THUNDERSTORMS. K-INDICES WILL BE AROUND 28. FREEZING LEVEL WILL BE AROUND 14K FEET. CONDITIONS FAVOR SHOWERS AND THUNDERSTORMS...BUT NOT FOR SEVERE WEATHER LOW LEVEL SHEAR WILL BE WEAK. ANOTHER WEAK SHORTWAVE RACING ALONG THE ZONAL FLOW WILL TRAVERSE THE AREA WEDNESDAY NIGHT AND THURSDAY. A WEAK FRONT SYSTEM WILL SLIDE THROUGH THE AREA. THE AIR MASS WILL BE A BIT DRIER...BUT THERE WILL STILL BE INSTABILITY TO KEEP A SLIGHT CHANCE GOING. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... EXPECT VFR CONDITIONS TO PREVAIL THROUGH THE FORECAST PERIOD. A SHORTWAVE TROUGH MOVING NORTH OF THE AREA COULD RESULT IN ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON ALTHOUGH CONDITIONAL COVERAGE WILL BE LOW ENOUGH TO LEAVE OUT MENTION. ANY LINGERING CONVECTION SHOULD DIE OFF AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING AND THE EXITING DISTURBANCE. ANOTHER SHORTWAVE WILL APPROACH UPPER MI WED BUT SHRA/TSRA CHANCES SHOULD HOLD TIL AFTER 18Z. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS/WAVES SHOULD REMAIN FAIRLY LIGHT ACROSS THE LAKE FOR THE NEXT SEVERAL DAYS. MODELS SUGGEST THAT WINDS WILL GENERALLY REMAIN SRLY THROUGH WED AS HIGH PRES SHIFTS EAST OF LAKE SUPERIOR. WINDS SHOULD SHIFT AROUND WEST OR NORTHWEST WED NIGHT INTO THU AS A TROUGH MOVES ACROSS THE AREA. WINDS WILL BACK SOUTHEAST OR EAST ON FRI AS ANOTHER LOW PRES TROUGH APPROACHES FROM THE NORTHERN PLAINS. ANOTHER WIND SHIFT TO WRLY IS EXPECTED FRI NIGHT INTO SAT AS THE SECOND TROUGH PASSES ACROSS THE AREA. EXPECT FOG OVER THE ERN PART OF THE LAKE TO CLEAR OUT LATER THIS MORNING AS SRLY WINDS INCREASE. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...DLG AVIATION...VOSS MARINE...VOSS mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1135 AM EDT TUE JUN 24 2008 .UPDATE... WV IMAGERY INDICATED A WELL-DEFINED SHORTWAVE TROUGH IN NW ONTARIO JUST NORTH OF KINL/KELO. SOME CONVECTION HAD ALREADY DEVELOPED WEST OF CYQT WITH THE BEST FORCING AND STEEPEST MID LEVEL LAPSE RATES NEAR 7 C/KM. OTHERWISE...LIGHT PCPN SPRINKLES/VIRGA OVER WESTERN LAKE SUPERIOR INTO W UPPER MI WERE DIMINISHING. VIS LOOP ALSO SHOWED CLOUDS SUPPORTED BY 305K-310K ISENTROPIC LIFT WERE ALSO THINNING OUT ACROSS UPPER MI ENOUGH TO ALLOW TEMPS TO CLIMB INTO THE LOWER 60S. MODIFIED FCST SOUNDINGS WITH MIXED LAYER REFLECTING TEMPS IN THE UPPER 70S AND AND DEWPOINTS IN THE LOWER 50S WOULD GIVE CAPE VALUES INTO THE 400-800 J/KG RANGE. ALTHOUGH THE STRONGEST QG FORCING AND UPPER LEVEL DIV WITH THE LEFT EXIT OF THE 80 KT 250 MB JET STREAK INTO NRN MN REMAINS NORTH OF THE CWA...EXPECT ISOLD/SCT COVERAGE OF SHRA/TSRA TO DEVELOP BY MID TO LATE AFTERNOON AS THE SHORTWAVE BRUSHES THE AREA. SOME UNCERTAINTY REMAINS ON THE AMOUNT OF INSTABILITY THAT MAY DEVELOP AS LOCAL HIGH RES WRF SOUNDINGS SUGGEST DEEP ENOUGH MIXING COULD PUSH MOISTURE VALUES LOW ENOUGH TO SIGNIFICANTLY REDUCE TSRA POTENTIAL. 0-6KM BULK SHEAR VALUES TO AROUND 40 KT COULD SUPPORT STORM ORGANIZATION FOR POSSIBILITY OF SEVERE HAIL OR ISOLD DAMAGING WIND GUSTS IF ANY STRONGER STORMS DEVELOP...PER SPC OUTLOOK. && .DISCUSSION... WATER VAPOR IMAGERY AND RUC SHOWING A TROUGH OVER QUEBEC AND A NEAR ZONAL FLOW ACROSS NORTHERN CONUS. WEAK SHORTWAVE TRAVELING ALONG THIS FLOW IS OVER SOUTHEAST MANITOBA EXTENDING INTO THE ARROWHEAD OF MINNESOTA THROUGH WESTERN WISCONSIN. OTHER SHORTWAVES ARE OVER SOUTHERN ALBERTA AND EASTERN WASHINGTON. SURFACE ANALYSIS DEPICTS A LARGE HIGH OVER THE UPPER GREAT LAKES AND THE OHIO RIVER VALLEY. A FRONTAL SYSTEM STRETCHES FROM SOUTH CAROLINA ACROSS THE SOUTHEASTERN STATES THEN INTO THE CENTRAL AND NORTHERN PLAINS. THE QUEBEC TROUGH WILL MOVE INTO THE CANADIAN MARITIME TODAY. THE SURFACE HIGH WILL START TO MOVE TO LOWER GREAT LAKES. 00Z UPWIND SOUNDINGS SHOWING A LAYER AROUND 750MB AND VERY DRY BELOW. NAM/GFS FORECAST SOUNDING SHOWING THIS WILL PREVAILS AS THE AIR MASSES MOVE THROUGH THE FORECAST AREA TODAY. THE MANITOBA AND MINNESOTA SHORTWAVE WILL TRACK ACROSS THE U.P. AS ANOTHER MOVES INTO NORTHEAST MINNESOTA. 300K ISENTROPIC ANALYSIS DEPICTS AN AREA OF ASCENT SLIDING INTO THE WESTERN U.P. BY LATE MORNING AND MOVE THROUGH THE AREA DURING THE AFTERNOON. THE FORECAST SOUNDINGS SUGGEST THAT VIRGA WILL FALL OVER THE AREA...BUT IT WILL NEED TO SATURATE THE DRY LOW LAYER BEFORE RAIN WILL OCCUR. THERE IS ENOUGH LOW LEVEL SHEAR AND LI`S AND INSTABILITY THAT CONVECTIVE WIND OUTFLOW AND LARGE HAIL COULD NOT BE RULED OUT. THUS LOW POPS CONTINUE TO BE IN ORDER. WITH WARM AIR ADVECTING INTO THE AREA FROM THE SOUTHWEST ON THE BACKSIDE OF THE HIGH...TEMPERATURES SHOULD BE A FEW DEGREES WARMER THAN MONDAY. A WEAK SHORTWAVE WILL RACE THROUGH THE AREA TONIGHT AS THE SURFACE HIGH SETTLES INTO THE EASTERN OHIO RIVER VALLEY. A SURFACE LOW WILL DEVELOPING OVER THE CENTRAL ONTARIO WILL TRACK TO THE SOUTH END OF JAMES BY 12Z WEDNESDAY. A LOW CENTER OVER THE CENTRAL PLAINS WILL EDGE INTO NORTHERN MINNESOTA. THE NOSE OF UPPER LEVEL JET MAX WILL RACE ACROSS THE FORECAST AREA EARLY THIS EVENING. THUS WILL KEEP A CHANCE ACROSS THE AREA THIS EVENING. AS DRIER...MORE STABLE AIR ENTERS THE AREA...WILL REDUCE THE CHANGES. ZONAL FLOW WILL CONTINUE ACROSS NORTHERN CONUS. A WEAK SHORTWAVE WILL SWEEP THROUGH THE AREA ON WEDNESDAY. THE UPPER LEVEL JET MAX WILL BE JUST NORTH OF THE AREA. LOW LEVEL MOISTURE WILL BE ENOUGH TO FEED SHOWERS AND THUNDERSTORMS. K-INDICES WILL BE AROUND 28. FREEZING LEVEL WILL BE AROUND 14K FEET. CONDITIONS FAVOR SHOWERS AND THUNDERSTORMS...BUT NOT FOR SEVERE WEATHER LOW LEVEL SHEAR WILL BE WEAK. ANOTHER WEAK SHORTWAVE RACING ALONG THE ZONAL FLOW WILL TRAVERSE THE AREA WEDNESDAY NIGHT AND THURSDAY. A WEAK FRONT SYSTEM WILL SLIDE THROUGH THE AREA. THE AIR MASS WILL BE A BIT DRIER...BUT THERE WILL STILL BE INSTABILITY TO KEEP A SLIGHT CHANCE GOING. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... EXPECT VFR CIGS AND VIS TO DOMINATE. A SHORTWAVE TROUGH/DISTURBANCE MOVING OVER THE AREA COULD RESULT IN A FEW SHOWERS AND THUNDERSTORMS THIS AFTERNOON ALTHOUGH COVERAGE WILL BE SUCH THAT I`VE ONLY INCLUDED A PROB30 FOR -SHRA AT KSAW FROM 21-01Z. I KEPT KCMX DRY AS SHORTWAVE WILL BE MOVING THROUGH THERE BEFORE BEST HEATING. ANY LINGERING CONVECTION SHOULD DIE OFF AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING AND THE EXITING DISTURBANCE. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS/WAVES SHOULD REMAIN FAIRLY LIGHT ACROSS THE LAKE FOR THE NEXT SEVERAL DAYS. MODELS SUGGEST THAT WINDS WILL GENERALLY REMAIN SRLY THROUGH WED AS HIGH PRES SHIFTS EAST OF LAKE SUPERIOR. WINDS SHOULD SHIFT AROUND WEST OR NORTHWEST WED NIGHT INTO THU AS A TROUGH MOVES ACROSS THE AREA. WINDS WILL BACK SOUTHEAST OR EAST ON FRI AS ANOTHER LOW PRES TROUGH APPROACHES FROM THE NORTHERN PLAINS. ANOTHER WIND SHIFT TO WRLY IS EXPECTED FRI NIGHT INTO SAT AS THE SECOND TROUGH PASSES ACROSS THE AREA. EXPECT FOG OVER THE ERN PART OF THE LAKE TO CLEAR OUT LATER THIS MORNING AS SRLY WINDS INCREASE. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...DLG AVIATION...VOSS MARINE...VOSS mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 742 AM EDT TUE JUN 24 2008 UPDATED FOR 12Z AVIATION DISCUSSION .DISCUSSION... WATER VAPOR IMAGERY AND RUC SHOWING A TROUGH OVER QUEBEC AND A NEAR ZONAL FLOW ACROSS NORTHERN CONUS. WEAK SHORTWAVE TRAVELING ALONG THIS FLOW IS OVER SOUTHEAST MANITOBA EXTENDING INTO THE ARROWHEAD OF MINNESOTA THROUGH WESTERN WISCONSIN. OTHER SHORTWAVES ARE OVER SOUTHERN ALBERTA AND EASTERN WASHINGTON. SURFACE ANALYSIS DEPICTS A LARGE HIGH OVER THE UPPER GREAT LAKES AND THE OHIO RIVER VALLEY. A FRONTAL SYSTEM STRETCHES FROM SOUTH CAROLINA ACROSS THE SOUTHEASTERN STATES THEN INTO THE CENTRAL AND NORTHERN PLAINS. THE QUEBEC TROUGH WILL MOVE INTO THE CANADIAN MARITIME TODAY. THE SURFACE HIGH WILL START TO MOVE TO LOWER GREAT LAKES. 00Z UPWIND SOUNDINGS SHOWING A LAYER AROUND 750MB AND VERY DRY BELOW. NAM/GFS FORECAST SOUNDING SHOWING THIS WILL PREVAILS AS THE AIR MASSES MOVE THROUGH THE FORECAST AREA TODAY. THE MANITOBA AND MINNESOTA SHORTWAVE WILL TRACK ACROSS THE U.P. AS ANOTHER MOVES INTO NORTHEAST MINNESOTA. 300K ISENTROPIC ANALYSIS DEPICTS AN AREA OF ASCENT SLIDING INTO THE WESTERN U.P. BY LATE MORNING AND MOVE THROUGH THE AREA DURING THE AFTERNOON. THE FORECAST SOUNDINGS SUGGEST THAT VIRGA WILL FALL OVER THE AREA...BUT IT WILL NEED TO SATURATE THE DRY LOW LAYER BEFORE RAIN WILL OCCUR. THERE IS ENOUGH LOW LEVEL SHEAR AND LI`S AND INSTABILITY THAT CONVECTIVE WIND OUTFLOW AND LARGE HAIL COULD NOT BE RULED OUT. THUS LOW POPS CONTINUE TO BE IN ORDER. WITH WARM AIR ADVECTING INTO THE AREA FROM THE SOUTHWEST ON THE BACKSIDE OF THE HIGH...TEMPERATURES SHOULD BE A FEW DEGREES WARMER THAN MONDAY. A WEAK SHORTWAVE WILL RACE THROUGH THE AREA TONIGHT AS THE SURFACE HIGH SETTLES INTO THE EASTERN OHIO RIVER VALLEY. A SURFACE LOW WILL DEVELOPING OVER THE CENTRAL ONTARIO WILL TRACK TO THE SOUTH END OF JAMES BY 12Z WEDNESDAY. A LOW CENTER OVER THE CENTRAL PLAINS WILL EDGE INTO NORTHERN MINNESOTA. THE NOSE OF UPPER LEVEL JET MAX WILL RACE ACROSS THE FORECAST AREA EARLY THIS EVENING. THUS WILL KEEP A CHANCE ACROSS THE AREA THIS EVENING. AS DRIER...MORE STABLE AIR ENTERS THE AREA...WILL REDUCE THE CHANGES. ZONAL FLOW WILL CONTINUE ACROSS NORTHERN CONUS. A WEAK SHORTWAVE WILL SWEEP THROUGH THE AREA ON WEDNESDAY. THE UPPER LEVEL JET MAX WILL BE JUST NORTH OF THE AREA. LOW LEVEL MOISTURE WILL BE ENOUGH TO FEED SHOWERS AND THUNDERSTORMS. K-INDICES WILL BE AROUND 28. FREEZING LEVEL WILL BE AROUND 14K FEET. CONDITIONS FAVOR SHOWERS AND THUNDERSTORMS...BUT NOT FOR SEVERE WEATHER LOW LEVEL SHEAR WILL BE WEAK. ANOTHER WEAK SHORTWAVE RACING ALONG THE ZONAL FLOW WILL TRAVERSE THE AREA WEDNESDAY NIGHT AND THURSDAY. A WEAK FRONT SYSTEM WILL SLIDE THROUGH THE AREA. THE AIR MASS WILL BE A BIT DRIER...BUT THERE WILL STILL BE INSTABILITY TO KEEP A SLIGHT CHANCE GOING. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... EXPECT VFR CIGS AND VIS TO DOMINATE. A SHORTWAVE TROUGH/DISTURBANCE MOVING OVER THE AREA COULD RESULT IN A FEW SHOWERS AND THUNDERSTORMS THIS AFTERNOON ALTHOUGH COVERAGE WILL BE SUCH THAT I`VE ONLY INCLUDED A PROB30 FOR -SHRA AT KSAW FROM 21-01Z. I KEPT KCMX DRY AS SHORTWAVE WILL BE MOVING THROUGH THERE BEFORE BEST HEATING. ANY LINGERING CONVECTION SHOULD DIE OFF AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING AND THE EXITING DISTURBANCE. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS/WAVES SHOULD REMAIN FAIRLY LIGHT ACROSS THE LAKE FOR THE NEXT SEVERAL DAYS. MODELS SUGGEST THAT WINDS WILL GENERALLY REMAIN SRLY THROUGH WED AS HIGH PRES SHIFTS EAST OF LAKE SUPERIOR. WINDS SHOULD SHIFT AROUND WEST OR NORTHWEST WED NIGHT INTO THU AS A TROUGH MOVES ACROSS THE AREA. WINDS WILL BACK SOUTHEAST OR EAST ON FRI AS ANOTHER LOW PRES TROUGH APPROACHES FROM THE NORTHERN PLAINS. ANOTHER WIND SHIFT TO WRLY IS EXPECTED FRI NIGHT INTO SAT AS THE SECOND TROUGH PASSES ACROSS THE AREA. EXPECT FOG OVER THE ERN PART OF THE LAKE TO CLEAR OUT LATER THIS MORNING AS SRLY WINDS INCREASE. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...DLG AVIATION...VOSS MARINE...VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 446 AM EDT TUE JUN 24 2008 .DISCUSSION... WATER VAPOR IMAGERY AND RUC SHOWING A TROUGH OVER QUEBEC AND A NEAR ZONAL FLOW ACROSS NORTHERN CONUS. WEAK SHORTWAVE TRAVELING ALONG THIS FLOW IS OVER SOUTHEAST MANITOBA EXTENDING INTO THE ARROWHEAD OF MINNESOTA THROUGH WESTERN WISCONSIN. OTHER SHORTWAVES ARE OVER SOUTHERN ALBERTA AND EASTERN WASHINGTON. SURFACE ANALYSIS DEPICTS A LARGE HIGH OVER THE UPPER GREAT LAKES AND THE OHIO RIVER VALLEY. A FRONTAL SYSTEM STRETCHES FROM SOUTH CAROLINA ACROSS THE SOUTHEASTERN STATES THEN INTO THE CENTRAL AND NORTHERN PLAINS. THE QUEBEC TROUGH WILL MOVE INTO THE CANADIAN MARITIME TODAY. THE SURFACE HIGH WILL START TO MOVE TO LOWER GREAT LAKES. 00Z UPWIND SOUNDINGS SHOWING A LAYER AROUND 750MB AND VERY DRY BELOW. NAM/GFS FORECAST SOUNDING SHOWING THIS WILL PREVAILS AS THE AIR MASSES MOVE THROUGH THE FORECAST AREA TODAY. THE MANITOBA AND MINNESOTA SHORTWAVE WILL TRACK ACROSS THE U.P. AS ANOTHER MOVES INTO NORTHEAST MINNESOTA. 300K ISENTROPIC ANALYSIS DEPICTS AN AREA OF ASCENT SLIDING INTO THE WESTERN U.P. BY LATE MORNING AND MOVE THROUGH THE AREA DURING THE AFTERNOON. THE FORECAST SOUNDINGS SUGGEST THAT VIRGA WILL FALL OVER THE AREA...BUT IT WILL NEED TO SATURATE THE DRY LOW LAYER BEFORE RAIN WILL OCCUR. THERE IS ENOUGH LOW LEVEL SHEAR AND LI`S AND INSTABILITY THAT CONVECTIVE WIND OUTFLOW AND LARGE HAIL COULD NOT BE RULED OUT. THUS LOW POPS CONTINUE TO BE IN ORDER. WITH WARM AIR ADVECTING INTO THE AREA FROM THE SOUTHWEST ON THE BACKSIDE OF THE HIGH...TEMPERATURES SHOULD BE A FEW DEGREES WARMER THAN MONDAY. A WEAK SHORTWAVE WILL RACE THROUGH THE AREA TONIGHT AS THE SURFACE HIGH SETTLES INTO THE EASTERN OHIO RIVER VALLEY. A SURFACE LOW WILL DEVELOPING OVER THE CENTRAL ONTARIO WILL TRACK TO THE SOUTH END OF JAMES BY 12Z WEDNESDAY. A LOW CENTER OVER THE CENTRAL PLAINS WILL EDGE INTO NORTHERN MINNESOTA. THE NOSE OF UPPER LEVEL JET MAX WILL RACE ACROSS THE FORECAST AREA EARLY THIS EVENING. THUS WILL KEEP A CHANCE ACROSS THE AREA THIS EVENING. AS DRIER...MORE STABLE AIR ENTERS THE AREA...WILL REDUCE THE CHANGES. ZONAL FLOW WILL CONTINUE ACROSS NORTHERN CONUS. A WEAK SHORTWAVE WILL SWEEP THROUGH THE AREA ON WEDNESDAY. THE UPPER LEVEL JET MAX WILL BE JUST NORTH OF THE AREA. LOW LEVEL MOISTURE WILL BE ENOUGH TO FEED SHOWERS AND THUNDERSTORMS. K-INDICES WILL BE AROUND 28. FREEZING LEVEL WILL BE AROUND 14K FEET. CONDITIONS FAVOR SHOWERS AND THUNDERSTORMS...BUT NOT FOR SEVERE WEATHER LOW LEVEL SHEAR WILL BE WEAK. ANOTHER WEAK SHORTWAVE RACING ALONG THE ZONAL FLOW WILL TRAVERSE THE AREA WEDNESDAY NIGHT AND THURSDAY. A WEAK FRONT SYSTEM WILL SLIDE THROUGH THE AREA. THE AIR MASS WILL BE A BIT DRIER...BUT THERE WILL STILL BE INSTABILITY TO KEEP A SLIGHT CHANCE GOING. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... EXPECT VFR CIGS AND VIS TO DOMINATE. THE ONLY FLY IN THE OINTMENT WILL BE A SHORTWAVE TROUGH/DISTURBANCE TUESDAY AFTERNOON. THIS SHOULD RESULT IN AFTERNOON SHOWERS AND THUNDERSTORMS. HINTED AT THIS AFTER 17Z WITH -SHRA AND CB AS CIGS FALL TO LOWER VFR RANGE. MAY NEED TO CLEARLY MENTION TS IN THE TAFS AS TIME NEARS AND THE POTENTIAL OF AN ACCURATE OCCURRENCE BECOME MORE LIKELY. THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL GREATLY DECREASE ONCE AGAIN WITH THE LOSS OF DAYTIME HEATING AND THE EXITING DISTURBANCE. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS/WAVES SHOULD REMAIN FAIRLY LIGHT ACROSS THE LAKE FOR THE NEXT SEVERAL DAYS. MODELS SUGGEST THAT WINDS WILL GENERALLY REMAIN SRLY THROUGH WED AS HIGH PRES SHIFTS EAST OF LAKE SUPERIOR. WINDS SHOULD SHIFT AROUND WEST OR NORTHWEST WED NIGHT INTO THU AS A TROUGH MOVES ACROSS THE AREA. WINDS WILL BACK SOUTHEAST OR EAST ON FRI AS ANOTHER LOW PRES TROUGH APPROACHES FROM THE NORTHERN PLAINS. ANOTHER WIND SHIFT TO WRLY IS EXPECTED FRI NIGHT INTO SAT AS THE SECOND TROUGH PASSES ACROSS THE AREA. EXPECT FOG OVER THE ERN PART OF THE LAKE TO CLEAR OUT LATER THIS MORNING AS SRLY WINDS INCREASE. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...DLG AVIATION...KF MARINE...VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 925 PM CDT WED JUN 25 2008 .UPDATE...THUNDERSTORMS THAT FIRED ALONG WARM FRONT DURING THE MID-AFTERNOON NEAR THE INTERNATIONAL BORDER HAS DECREASED OR HAS MOVED OUT INTO LAKE SUPERIOR. WITH THE SOLAR HEATING DECREASING AND THE CAP OVER AREA...THERE SHOULD BE LITTLE DEVELOPMENT OVERNIGHT AS RIDGE BUILDS INTO AREA. THIS WILL GIVE FORECAST AREA A BREAK DURING THE DAY THURSDAY BEFORE NEXT LOW PRESSURE APPROACHS THE AREA THURSDAY EVENING GIVING THE AREA ANOTHER SHOT FOR SEVERE WEATHER THURSDAY NIGHT AND FRIDAY. REST OF FCST UNCHANGED. STEWART && .PREV DISCUSSION... /ISSUED 308 PM CDT WED JUN 25 2008/ DISCUSSION... CURRENT SFC ANALYSIS DEPICTING LOW PRESSURE CENTERED NEAR KINL...WITH WEAK COLD FRONT DRAPED SOUTH THROUGH KHIB TO KROS. EARLIER OVERRUNNING CONVECTION FROM THIS MORNING HAS MOVED EAST OF THE ARROWHEAD REGION. SEVERE WX PARAMETERS THROUGH LATE THIS AFTERNOON FOCUSED ON THE ARROWHEAD REGION...AS WELL AS NW WI...THOUGH FORCING FOR CONVECTION QUESTIONABLE OVER NW WI. MSAS ANALYSIS DEPICTING TONGUE OF HIGHEST POTENTIAL TEMPS AND TD`S EXTENDING NORTH THROUGH CENTRAL ST LOUIS COUNTY. LATEST RUC SOUNDINGS FROM KELO DEPICTING LI VALUES -3 TO -4 THROUGH LATE THIS AFTERNOON. DEEP LAYER SHEAR OF 40 TO 50 KTS WILL BE CONDUCIVE FOR SEVERE THUNDERSTORMS. LOW PRESSURE AND ATTENDANT COLD FRONT MOVE EAST OVERNIGHT... ALLOWING FOR HIGH PRESSURE TO BUILD IN. A WARM AND PLEASANT DAY ON TAP FOR THURSDAY BEFORE NEXT SYSTEM AFFECTS THE NORTHLAND. STRONG WAVE PROGGED TO DROP SOUTHEASTWARD FROM CANADA ON FRIDAY. RETURN FLOW FROM THE SOUTH OVERNIGHT THURSDAY...AND APPROACHING LOW PRESSURE WILL TRIGGER TS OVER THE DAKOTAS THURSDAY NIGHT. SRLY LLJ INCREASES TO 50KTS FRI MORNING ACROSS CENTRAL MN...WITH ONGOING SHOWERS AND THUNDERSTORMS QUICKLY PROPAGATING THROUGH CWA. ATTM... BEST CHANCE FOR SEVERE IS ACROSS SW CWA...WHERE MAX INSTABILITY AND LIFT IS FOCUSED. SEE DAY 2 OUTLOOK ISSUED BY SPC FOR DETAILS. INTRODUCED LIKELY POPS ON FRIDAY...AS MODELS ARE IN DECENT AGREEMENT ON PLACEMENT OF SYNOPTIC FEATURES. CONFIDENCE NOT AS GREAT FRI EVENING...AS GFS SHOWING STRONGER DOUBLE BARREL LOW DEVELOPING AND DRY SLOT PUNCHING INTO SRN ZONES...WITH ECMWF SLIGHTLY WEAKER WITH SFC FEATURE. WEEKEND SHAPING UP TO BE COOL AND WET AS UPPER LOW BECOMES QUASI STATIONARY OVER THE UPPER GREAT LAKES. ECMWF SLIGHTLY FASTER WITH MOVING THE SYSTEM OUT BY SUNDAY...WITH GFS HANGING ON THROUGH EARLY MONDAY. EITHER WAY...SHOULD SEE BELOW NORMAL TEMPS THIS WEEKEND. AVIATION... SCATTERED THUNDERSTORMS WITH GUSTY WINDS AND MVFR/IFR VSBYS/CIGS ARE EXPECTED TO DEVELOP THIS AFTERNOON ALONG A COLD FRONT TRACKING SOUTHEAST ACROSS THE NORTHLAND. THE STORMS WILL MOVE SOUTHEAST WITH THE FRONT THIS EVENING...AND SHOULD MOVE SOUTH OF THE AREA AFTER MIDNIGHT. THERE IS A SLIGHT RISK THAT SOME STORMS MAY BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS. HIGH PRESSURE WILL BUILD IN OVER THE REGION BY THURSDAY RESULTING IN DRY CONDITIONS. SKIES SHOULD CLEAR OUT TONIGHT AND WINDS WILL BECOME LIGHT...ALLOWING FOR THE FORMATION OF FOG WITH IFR/MVFR VSBYS LATE TONIGHT AND EARLY THURSDAY MORNING. && POINT TEMPS/POPS... DLH 54 81 53 69 / 10 10 20 60 INL 51 82 56 74 / 10 10 20 60 BRD 58 84 60 75 / 10 10 50 50 HYR 55 84 55 74 / 10 10 40 60 ASX 54 80 56 73 / 10 10 10 60 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ STEWART mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 308 PM CDT WED JUN 25 2008 .DISCUSSION... CURRENT SFC ANALYSIS DEPICTING LOW PRESSURE CENTERED NEAR KINL...WITH WEAK COLD FRONT DRAPED SOUTH THROUGH KHIB TO KROS. EARLIER OVERRUNNING CONVECTION FROM THIS MORNING HAS MOVED EAST OF THE ARROWHEAD REGION. SEVERE WX PARAMETERS THROUGH LATE THIS AFTERNOON FOCUSED ON THE ARROWHEAD REGION...AS WELL AS NW WI...THOUGH FORCING FOR CONVECTION QUESTIONABLE OVER NW WI. MSAS ANALYSIS DEPICTING TONGUE OF HIGHEST POTENTIAL TEMPS AND TD`S EXTENDING NORTH THROUGH CENTRAL ST LOUIS COUNTY. LATEST RUC SOUNDINGS FROM KELO DEPICTING LI VALUES -3 TO -4 THROUGH LATE THIS AFTERNOON. DEEP LAYER SHEAR OF 40 TO 50 KTS WILL BE CONDUCIVE FOR SEVERE THUNDERSTORMS. LOW PRESSURE AND ATTENDANT COLD FRONT MOVE EAST OVERNIGHT... ALLOWING FOR HIGH PRESSURE TO BUILD IN. A WARM AND PLEASANT DAY ON TAP FOR THURSDAY BEFORE NEXT SYSTEM AFFECTS THE NORTHLAND. STRONG WAVE PROGGED TO DROP SOUTHEASTWARD FROM CANADA ON FRIDAY. RETURN FLOW FROM THE SOUTH OVERNIGHT THURSDAY...AND APPROACHING LOW PRESSURE WILL TRIGGER TS OVER THE DAKOTAS THURSDAY NIGHT. SRLY LLJ INCREASES TO 50KTS FRI MORNING ACROSS CENTRAL MN...WITH ONGOING SHOWERS AND THUNDERSTORMS QUICKLY PROPAGATING THROUGH CWA. ATTM... BEST CHANCE FOR SEVERE IS ACROSS SW CWA...WHERE MAX INSTABILITY AND LIFT IS FOCUSED. SEE DAY 2 OUTLOOK ISSUED BY SPC FOR DETAILS. INTRODUCED LIKELY POPS ON FRIDAY...AS MODELS ARE IN DECENT AGREEMENT ON PLACEMENT OF SYNOPTIC FEATURES. CONFIDENCE NOT AS GREAT FRI EVENING...AS GFS SHOWING STRONGER DOUBLE BARREL LOW DEVELOPING AND DRY SLOT PUNCHING INTO SRN ZONES...WITH ECMWF SLIGHTLY WEAKER WITH SFC FEATURE. WEEKEND SHAPING UP TO BE COOL AND WET AS UPPER LOW BECOMES QUASI STATIONARY OVER THE UPPER GREAT LAKES. ECMWF SLIGHTLY FASTER WITH MOVING THE SYSTEM OUT BY SUNDAY...WITH GFS HANGING ON THROUGH EARLY MONDAY. EITHER WAY...SHOULD SEE BELOW NORMAL TEMPS THIS WEEKEND. && .AVIATION... SCATTERED THUNDERSTORMS WITH GUSTY WINDS AND MVFR/IFR VSBYS/CIGS ARE EXPECTED TO DEVELOP THIS AFTERNOON ALONG A COLD FRONT TRACKING SOUTHEAST ACROSS THE NORTHLAND. THE STORMS WILL MOVE SOUTHEAST WITH THE FRONT THIS EVENING...AND SHOULD MOVE SOUTH OF THE AREA AFTER MIDNIGHT. THERE IS A SLIGHT RISK THAT SOME STORMS MAY BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS. HIGH PRESSURE WILL BUILD IN OVER THE REGION BY THURSDAY RESULTING IN DRY CONDITIONS. SKIES SHOULD CLEAR OUT TONIGHT AND WINDS WILL BECOME LIGHT...ALLOWING FOR THE FORMATION OF FOG WITH IFR/MVFR VSBYS LATE TONIGHT AND EARLY THURSDAY MORNING. && POINT TEMPS/POPS... DLH 54 81 53 69 / 10 10 20 60 INL 51 82 56 74 / 10 10 20 60 BRD 58 84 60 75 / 10 10 50 50 HYR 55 84 55 74 / 10 10 40 60 ASX 54 80 56 73 / 10 10 10 60 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ LONKA/BERDES mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DULUTH MN 1000 AM CDT WED JUN 25 2008 .UPDATE... ONGOING ELEVATED CONVECTION IN TIP OF THE ARROWHEAD SHOULD BEGIN TO TAPER OFF BY LATE MORNING. EXPECT REDEVELOPMENT AFT 18Z IN THE ARROWHEAD AS WELL AS NORTHWEST WISCONSIN...WHERE FORCING AND MOISTURE WILL BE MAXIMIZED. DEEP LAYER SHEAR OF 40-50KT AND CAPE VALUES OF 1500-2500J/KG SUFFICIENT FOR SCATTERED SEVERE THUNDERSTORMS HERE. TOOK MENTION OF TSRA OUT OF WRN ZONES THIS AFTERNOON...AS LATEST RUC/NAM SOUNDINS SHOWING DRY AIR MOVING IN. && .PREV DISCUSSION... /ISSUED 318 AM CDT WED JUN 25 2008/ DISCUSSION...MAIN FORECAST CHALLENGE IS RESOLVING CONVECTIVE CHANCES IN THE SHORT TERM. DLH FORECAST AREA REMAINS UNDER ACTIVE ZONAL FLOW ALOFT. MOSAIC REGIONAL RADAR SHOWS NON-SEVERE CONVECTIVE COMPLEX CONTINUING EASTWARD AFFECTING THE SW FA THIS EARLY MORNING. ASSOCIATED VORT MAX IS WEAKENING...RESULTING IN CONTINUE DECAY OF THIS MCS THIS MORNING. MEANWHILE...NEXT MORE POTENT VORT MAX ATTM IS PUSHING THROUGH SOUTHERN MANITOBA/NORTH DAKOTA PER WATER VAPOR IMAGERY. NOSE OF 30+ KT LOW LEVEL JET AHEAD OF THIS SHORT WAVE HAS TRIGGERED SOME ELEVATED CONVECTION ACROSS NORTHWEST MINNESOTA THIS EARLY MORNING AS WELL. THIS CONVECTIVE ACTIVITY LOOKS TO CONTINUE ENE TRAJECTORY ALONG AND NORTH OF THE INTERNATIONAL BORDER AS LLJ VEERS THIS MORNING. WITH CONTINUED LOW LEVEL WARM AIR/THETA-E ADVECTION TODAY AHEAD OF MAIN SFC TROUGH/COLD FRONT...INSTABILITY REALLY INCREASES...WITH NAM FORECAST SOUNDINGS SHOWING SBCAPES OF 2500-3000 J/KG ACROSS THE EASTERN FA THIS AFTERNOON. DEEP LAYER SHEAR IS MODERATE TO GOOD WITH 0-6 KM SHEAR VALUES OF 35 TO 50 KT THIS AFTERNOON...SUFFICIENT FOR ORGANIZED STRONG TO SEVERE CONVECTION. THIS FRONT AND CONVECTION SHOULD PUSH OFF TO THE SOUTHEAST LATE THIS EVENING...WITH COOLER HIGH PRESSURE BUILDING IN FROM THE NORTH. PATCHY FOG MAY BE POSSIBLE...DEPENDING ON THE AMOUNT OF RAIN RECEIVED...WITH MAINLY CLEAR SKIES AND LIGHT WINDS OVERNIGHT. THURSDAY LOOKS QUIET ATTM WITH MAIN BAROCLINIC ZONE REMAINING STRETCHED ACROSS SOUTHERN MINNESOTA/SOUTHERN WISCONSIN...AND HIGH PRESSURE ACROSS THE NORTHLAND. WILL SEE A STRONG THETA-E RIDGE BUILDING ACROSS THE NORTHERN PLAINS THURSDAY NIGHT AND FRIDAY IN RESPONSE TO NEXT DEEPENING TROUGH. STRONG LIFT...ALONG WITH AMPLE MOISTURE SHOULD BRING WIDESPREAD CONVECTION TO THE FA THURSDAY NIGHT INTO FRIDAY. THE TROUGH DEEPENS BECOMING A CLOSED LOW OVER MINNESOTA/WISCONSIN FRIDAY NIGHT AND SATURDAY. THERE ARE SOME MODEL DIFFERENCES STILL WITH THE TIMING ON THE DEPARTURE OF THIS LOW...BUT IT LOOKS LIKE A COOLER AND WETTER WEEKEND ACROSS THE NORTHLAND ATTM. AVIATION...A TROUGH OF LOW PRESSURE WILL MOVE FROM FAR WESTERN MINNESOTA THIS MORNING...TO FAR EASTERN MINNESOTA BY LATE AFTERNOON...THEN THROUGH WESTERN WISCONSIN THIS EVENING. THUNDERSTORMS WILL BE POSSIBLE ALONG THIS TROUGH. MAINLY VFR CONDITIONS WILL PREVAIL...BUT MVFR OR EVEN SOME IFR CEILINGS AND VSBYS WILL OCCUR WITH THE STRONGER STORMS. THE CHANCE FOR STORMS WILL END FROM WEST TO EAST AS THE TROUGH PASSES THROUGH...AND SHOULD BE DONE ALL AREAS BY MIDNIGHT. PATCHY FOG WILL BE POSSIBLE LATE TONIGHT AS HIGH PRESSURE BRIEFLY BUILDS IN. && POINT TEMPS/POPS... DLH 83 56 80 55 / 30 10 10 20 INL 81 51 82 57 / 30 10 10 30 BRD 85 59 84 60 / 20 10 10 40 HYR 85 56 84 56 / 30 10 10 30 ASX 84 56 80 54 / 30 20 10 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ LONKA/BERDES mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 440 AM CDT WED JUN 25 2008 .DISCUSSION... /330 AM CDT WED JUN 25 2008/ Q-STATIONARY FRONT DRAPED ACROSS MISSOURI ALONG WITH STRONG NOCTURNAL LOW LEVEL JET HAS TOUCHED OFF A HEAVY RAIN PRODUCING MCS. THE HEAVIEST RAIN HAS BEEN FALLING ACROSS NORTH CENTRAL AND CENTRAL MISSOURI...JUST OUTSIDE OUR CWFA. HOWEVER...RADAR ESTIMATES OF 2-3 INCHES OF RAIN AT THIS TIME WITH MORE ON THE WAY ACROSS KNOX...LEWIS...MARION...SHELBY...AND ADAMS COUNTIES. HAVE THEREFORE DECIDED TO CONTINUE THE FLASH FLOOD WATCH THROUGH NOON TODAY. IT STILL LOOKS...BASED ON RADAR TRENDS...LIKE THE SOUTHERN EXTENT OF THE HEAVY RAIN WILL FALL WITHIN THE WATCH AREA THIS MORNING SO DID NOT EXPAND THE AREA AT THIS TIME. OUTFLOW BOUNDARY FROM THIS MORNING`S MCS WILL LIKELY BE HANGING AROUND THE CWFA THIS AFTERNOON. THIS BOUNDARY WOULD PROVIDE A GOOD FOCUS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT. RUC IS FORECASTING MLCAPES GREATER THAN 1600 J/KG AND MUCAPES GREATER THAN 4000 JOULES BY 18Z. THIS IS OBVIOUSLY MORE THAN ENOUGH ENERGY FOR THUNDERSTORMS TO REDEVELOP. NOT SURE THOUGH WHAT THE COVERAGE WILL BE THIS AFTERNOON SO MAINLY KEPT JUST CHANCES GOING. THE SURFACE BOUNDARY MOVES FURTHER NORTH INTO IOWA TONIGHT AND APPEARS TO TAKE THE THREAT FOR HEAVY RAIN WITH IT AT LEAST THROUGH FRIDAY MORNING. THERE`S STILL THE CHANCE THAT WE`LL SEE SOME SCATTERED THUNDERSTORMS...BUT ORGANIZED MCS ACTIVITY SHOULD STAY NORTH OF THE CWFA WHERE THE LOW LEVEL JET MOVES OVERTOP OF THE BOUNDARY AND INTERACTS WITH SEVERAL PASSING SHORTWAVES. UNFORTUNATELY THIS MEANS MORE WATER IN THE MISSISSIPPI RIVER SYSTEM. NOT SURE YET HOW THIS WILL IMPACT RIVER FORECASTS...WHETHER THE RIVER WILL RISE AGAIN...OR IF IT WILL JUST DELAY THE PREVIOUSLY FORECASTED FALL. EITHER WAY THIS IS NOT GOOD NEWS. THE NEXT SHOT FOR HEAVY RAINFALL LOOKS TO BE FRIDAY NIGHT AND SATURDAY AS A SLOW MOVING COLD FRONT MOVES SOUTHEAST ACROSS MISSOURI AND ILLINOIS. HPC GUIDANCE PRINTED OUT OVER AN INCH OF QPF ACROSS THE AREA FRIDAY NIGHT. DID NOT GO THAT HIGH IN MY QPF FORECAST YET AS THERE IS STILL A LOT OF UNCERTAINTY IN THE QPF FORECAST OUT THAT FAR...THOUGH THIS IS OBVIOUSLY A POSSIBILITY THAT WILL HAVE TO BE WATCHED CLOSELY OVER THE NEXT COUPLE OF DAYS. CARNEY && .AVIATION... /1051 PM CDT TUE JUN 24 2008/ FOR THE 06Z TAFS...SCT TSRA CONT TO DVLP N OF A WRMFNT CURRENTLY EXTDG FM NR MCI SE TO NR STL...AND ALSO AHD OF AN MCV MOVG SLOWLY EWD THRU S CNTRL IA. THE SWLY LLJ IS FCST TO FOCUS BOTH LOW LVL TEMPERATURE AND MOISTURE ADVCTN TO NERN MO LT TGT. LOOKING AT LATEST RADAR TRENDS WILL INCLUDE PREVAILING TSRA IN UIN OR AT LEAST A TEMPO GRP OF TSRA IN UIN TIL AT LEAST 08Z WED. IT APRS THAT THE TSRA OVER NRN MO WILL REMAIN N OF COU..STL AND SUS LT TGT. THE BEST THREAT OF CONVECTION SHOULD SHIFT NWD ON WED AS THE WRMFNT IS FCST TO MOVE NWD THRU NRN MO LT TGT AND INTO IA ON WED. OUTSIDE OF THE STORMS THERE SHOULD BE HI LVL CONVECTIVE DEBRIS CLOUDINESS ALONG WITH SOME WAA MID LVL CLOUDINESS AS WELL. WITH THE WRMFNT LIFTING NWD THE SELY SFC WNDS AT THE TAF SITES WILL GRADUALLY VEER ARND TO A SLY DIRECTION LT TGT THEN TO A SWLY DIRECTION ON WED. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...FLASH FLOOD WATCH UNTIL NOON CDT TODAY FOR KNOX-LEWIS-MARION- MONROE-RALLS-SHELBY. FLASH FLOOD WATCH THROUGH THIS EVENING FOR LINCOLN. IL...FLASH FLOOD WATCH UNTIL NOON CDT TODAY FOR ADAMS IL-BROWN IL- PIKE IL. && $$ WFO LSX mo AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE HASTINGS NE 942 PM CDT WED JUN 25 2008 .DISCUSSION...DUE TO THE ONGOING CONVECTION IN NORTHWESTERN KANSAS...THIS LOOKS LIKE IT IS HOLDING TOGETHER AND COULD AFFECT PARTS OF OUR KANSAS COUNTIES AT LEAST IN THE EARLY OVERNIGHT HOURS THAT DID NOT MENTION THUNDERSTORMS IN THE PREVIOUS FORECAST. THE INCREASING LOW-LEVEL JET SHOULD HELP KEEP THESE STORMS GOING OVERNIGHT AS WELL. AS FAR AS MODELS ARE CONCERNED...QPF FIELDS ARE GENERALLY WORTHLESS AND HAVE BEEN IGNORED. && .PREV DISCUSSION... /ISSUED 645 PM CDT WED JUN 25 2008/ AVIATION...00Z KGRI TAF. VFR CONDITIONS FOR THIS FORECAST. THUNDERSTORM ACTIVITY LOOKS LIKE IT WILL BE MUCH LATER FOR THE AREA...AND SHOULD REMAIN PRIMARILY TO THE WEST AND SOUTHWEST OF THE TERMINAL. WIND SHOULD REALLY START MIXING AND GUSTING FROM THE SOUTH ON THURSDAY AFTERNOON. STORMS THURSDAY NIGHT SHOULD HOLD OFF UNTIL AFTER THIS FORECAST VALID TIME. PREV DISCUSSION... /ISSUED 355 PM CDT WED JUN 25 2008/ SHORT TERM...FOR TONIGHT THROUGH THURSDAY NIGHT. LATEST WATER VAPOR IMAGERY REVEALS A FAIRLY ZONAL FLOW REGIME ACROSS THE NORTHERN HALF OF THE CONUS WITH SEVERAL SMALL BUT POTENT WAVES EMBEDDED WITHIN THIS UPPER FLOW PATTERN. ONE OF THESE WAVES IS CURRENTLY SLIDING OUT OF THE HIGH PLAINS WHILE A SECOND WAVE IS SEEN PUSHING INTO THE ROCKIES. RECENT OBJECTIVE SURFACE ANALYSIS SHOWS TWO BOUNDARIES OF INTEREST ACROSS THE AREA WITH A DIFFERENTIAL HEATING BOUNDARY STRETCHING FROM NEAR MCCOOK TO AROUND GRAND ISLAND WHILE WEAK SURFACE TROUGH IS SEEN STRETCHING FROM NORTHERN IOWA INTO NORTH CENTRAL NEBRASKA. LOOKING AT RUC ANALYSIS...ML CAPES OF 3000 TO AS HIGH AS 4500 J/KG ARE SEEN FROM NORTHERN KANSAS INTO CENTRAL NEBRASKA ALTHOUGH MOST OF THIS AREA CONTINUES TO HAVE MODEST TO STRONG INHIBITION. HOWEVER...WEAKER INHIBITION IS SHOWN ACROSS NORTH CENTRAL NEBRASKA AND AGAIN ACROSS NORTHWESTERN KANSAS. TAKING A LOOK AT VISIBLE SAT IMAGERY IN THESE WEAKER INHIBITION AREAS...A SMALL CLUSTER OF CU IS VISIBLE NEAR KGLD BUT LITTLE IS SHOWN ACROSS NORTH CENTRAL NEBRASKA. MAIN QUESTION AS THE AREA HEADS INTO THIS EVENING TO OVERNIGHT IS WHERE DEEP CONVECTION MAY DEVELOP. INITIAL PROBLEM WITH DEVELOPING DEEP CONVECTION ACROSS THE AREA LATE THIS AFTERNOON TO EARLY EVENING IS THAT FORCING FROM THE FIRST WAVE MOVING THROUGH THE REGION NOW...IS SHOWN TO SLIDE EAST OF THE FORECAST AREA BY EARLY EVENING. GIVEN THE TIMING OF THIS WAVE PRODUCING INCREASING MID LEVEL SUBSIDENCE ALONG WITH A LACK OF ANY CONVECTIVE DEVELOPMENT OVER THE REGION THIS AFTERNOON...CONFIDENCE IS LOW THAT DEEP CONVECTION WILL DEVELOP THROUGH EARLY EVENING. WILL OPT TO KEEP A SLIGHT CHANCE OVER MOST OF THE CWA BUT THIS MAY NEED TO BE REMOVED BY THE EVENING SHIFT IF NOTHING DEVELOPS. IF SOMETHING DOES DEVELOP...SEVERE THREAT LOOKS MARGINAL AS EFFECTIVE DEEP LAYER SHEAR WILL REMAIN WEAK AT 15 TO 25 KNOTS AT BEST. WILL KEEP MENTION OF SEVERE BUT WILL DECREASE MAX HAIL SIZE DOWN TO PENNY TO QUARTER SIZE. HOWEVER...AS THE EVENING PROGRESSES INTO THE OVERNIGHT HOURS A 30 TO 40 KT LLJ IS SHOWN TO NOSE INTO THE AREA WITH WHATEVER CONVECTION REMAINS ACROSS THE HIGH PLAINS SLIDING EAST INTO THE CWA. COVERAGE OF STORMS LOOKS SMALL...BUT WILL KEEP A SLIGHT CHANCE OVER MOST OF THE CWA THROUGH THE NIGHT. THURSDAY AFTERNOON INTO THURSDAY NIGHT IS THEN SHAPING UP TO BE AN ACTIVE TIME FRAME ACROSS THE REGION. A WEAK AREA OF LOW PRESSURE IS SHOWN BY THE MODELS TO SPIN UP OVER NORTH CENTRAL NEBRASKA WITH A WARM FRONT SEEN EXTENDING EAST ACROSS NORTHERN NEBRASKA WHILE A DRYLINE STRETCHES SOUTH ACROSS FAR WESTERN SECTIONS OF THE FORECAST AREA GENERALLY NEAR HIGHWAY 283. DEEP LOW LEVEL MOISTURE WILL BE AVAILABLE AHEAD OF THE DRYLINE AND ON EITHER SIDE OF THE WARM FRONT. THIS IS SHOWN TO PRODUCE ML CAPES OF 2000 TO 2500 J/KG NEAR THE DRYLINE AND 3000 TO 3500 J/KG NEAR THE WARM FRONT. A HEALTHY SHORT WAVE IS SHOWN TO RIDE OUT OF THE ROCKIES INTO THE PLAINS DURING THE AFTERNOON AND EXPECT THIS TO TRIGGER ISOLATED CONVECTIVE DEVELOPMENT ALONG THE DRYLINE AND MORE SCATTERED DEVELOPMENT JUST NORTH OF THE CWA NEAR THE WARM FRONT. SEVERE CONVECTION WISE...EFFECTIVE DEEP LAYER SHEAR WILL BE RATHER WEAK ALONG DRYLINE BY MID TO LATE AFTERNOON WITH VALUES OF 10 TO 25 KNTS AT BEST. THIS SHOULD KEEP CONVECTION ON THE WEAKER SIDE OVER THIS PORTION OF FORECAST AREA. HOWEVER...WITH SURFACE WINDS BACKING AROUND TO A MORE EASTERLY DIRECTION CLOSER TO THE WARM FRONT...EFFECTIVE DEEP LAYER SHEAR OF 25 TO NEAR 40 KNTS SHOULD SUPPORT GOOD CELL ORGANIZATION AND POSSIBLE ROTATION. TORNADO THREAT LOOKS MINIMAL BUT LARGE HAIL THREAT LOOKS POSSIBLE MAINLY NORTH OF HIGHWAY 92. TEMPERATURE WISE...A VERY WARM AFTERNOON LOOKS ON TAP WITH HIGHS RANGING FROM THE LOWER TO MID 90S NEAR ORD TO OSCEOLA...TO THE MID 90S TO AROUND 100 ACROSS NORTH CENTRAL KANSAS. LONG TERM...12Z FRIDAY THROUGH WEDNESDAY. A COLD FRONT WILL BE ON TOP OF THE CWFA FRIDAY MORNING...AS MAY LEFTOVER SHOWERS AND DEBRIS CLOUDS FROM ANY THURSDAY NIGHT MCS ACTIVITY. THE MODELS ARE ALL VERY SIMILAR IN TIMING THE FRONT THROUGH ALL BUT THE FAR SOUTHEAST CFWA AS EARLY AS MIDDAY...AND THAT MAY BE TOO SLOW IF CONVECTION THURSDAY NIGHT PUSHES HAS ANY SAY. POINT IS...WITH CLOUDS LINGERING...AND FRONT ON THE MOVE...THE BEST CHANCE FOR ANY PRECIPITATION FRIDAY WILL BE EAST/SOUTHEAST CWFA. KEPT A SMALL RISK FOR FRIDAY NIGHT...IN CASE POST FRONTAL ELEVATED PRECIPITATION CAN FORM...WHICH IT OFTEN DOES FOR A TIME IN THESE SITUATIONS. THE WEEKEND LOOKS ADMIRABLE WEATHER WISE. ANOMALOUSLY DRY AIR IS FORECAST TO COME INTO THE CENTRAL PLAINS BEHIND COLD FRONT FRIDAY...DRIVEN BY GREAT LAKES REGION LOW PRESSURE. PWAT VALUES ARE FORECAST TO BE IN THE LOWER HALF OF CLIMATOLOGY VALUES. THOUGH DEWPOINTS MAY BE HELD UP SLIGHTLY WITH EVAPOTRANSPIRATION AND RECENT RAINFALL ISSUES...IT SHOULD STILL FEEL MUCH MORE PLEASANT WITH DEWPOINTS IN THE 50S FOR MOST AREAS. NEXT SHOT FOR A STORM OR TWO COULD COME MONDAY EVENING IN THE WESTERN ZONES...AS A STORM MAY FLOUNDER IN FROM THE HIGH PLAINS. LITTLE BETTER RISK OF STORMS POSSIBLE TUESDAY/WEDNESDAY...AS THE RIPPLE EFFECT RETURNS WITH A WEAK WAVE CUTTING THROUGH THE RIDGE. TEMPERATURES SHOULD GRADUALLY WARM A FEW DEGREES EACH BEGINNING SATURDAY. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ HEINLEIN ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 645 PM CDT WED JUN 25 2008 .AVIATION...00Z KGRI TAF. VFR CONDITIONS FOR THIS FORECAST. THUNDERSTORM ACTIVITY LOOKS LIKE IT WILL BE MUCH LATER FOR THE AREA...AND SHOULD REMAIN PRIMARILY TO THE WEST AND SOUTHWEST OF THE TERMINAL. WIND SHOULD REALLY START MIXING AND GUSTING FROM THE SOUTH ON THURSDAY AFTERNOON. STORMS THURSDAY NIGHT SHOULD HOLD OFF UNTIL AFTER THIS FORECAST VALID TIME. && .PREV DISCUSSION... /ISSUED 355 PM CDT WED JUN 25 2008/ SHORT TERM...FOR TONIGHT THROUGH THURSDAY NIGHT. LATEST WATER VAPOR IMAGERY REVEALS A FAIRLY ZONAL FLOW REGIME ACROSS THE NORTHERN HALF OF THE CONUS WITH SEVERAL SMALL BUT POTENT WAVES EMBEDDED WITHIN THIS UPPER FLOW PATTERN. ONE OF THESE WAVES IS CURRENTLY SLIDING OUT OF THE HIGH PLAINS WHILE A SECOND WAVE IS SEEN PUSHING INTO THE ROCKIES. RECENT OBJECTIVE SURFACE ANALYSIS SHOWS TWO BOUNDARIES OF INTEREST ACROSS THE AREA WITH A DIFFERENTIAL HEATING BOUNDARY STRETCHING FROM NEAR MCCOOK TO AROUND GRAND ISLAND WHILE WEAK SURFACE TROUGH IS SEEN STRETCHING FROM NORTHERN IOWA INTO NORTH CENTRAL NEBRASKA. LOOKING AT RUC ANALYSIS...ML CAPES OF 3000 TO AS HIGH AS 4500 J/KG ARE SEEN FROM NORTHERN KANSAS INTO CENTRAL NEBRASKA ALTHOUGH MOST OF THIS AREA CONTINUES TO HAVE MODEST TO STRONG INHIBITION. HOWEVER...WEAKER INHIBITION IS SHOWN ACROSS NORTH CENTRAL NEBRASKA AND AGAIN ACROSS NORTHWESTERN KANSAS. TAKING A LOOK AT VISIBLE SAT IMAGERY IN THESE WEAKER INHIBITION AREAS...A SMALL CLUSTER OF CU IS VISIBLE NEAR KGLD BUT LITTLE IS SHOWN ACROSS NORTH CENTRAL NEBRASKA. MAIN QUESTION AS THE AREA HEADS INTO THIS EVENING TO OVERNIGHT IS WHERE DEEP CONVECTION MAY DEVELOP. INITIAL PROBLEM WITH DEVELOPING DEEP CONVECTION ACROSS THE AREA LATE THIS AFTERNOON TO EARLY EVENING IS THAT FORCING FROM THE FIRST WAVE MOVING THROUGH THE REGION NOW...IS SHOWN TO SLIDE EAST OF THE FORECAST AREA BY EARLY EVENING. GIVEN THE TIMING OF THIS WAVE PRODUCING INCREASING MID LEVEL SUBSIDENCE ALONG WITH A LACK OF ANY CONVECTIVE DEVELOPMENT OVER THE REGION THIS AFTERNOON...CONFIDENCE IS LOW THAT DEEP CONVECTION WILL DEVELOP THROUGH EARLY EVENING. WILL OPT TO KEEP A SLIGHT CHANCE OVER MOST OF THE CWA BUT THIS MAY NEED TO BE REMOVED BY THE EVENING SHIFT IF NOTHING DEVELOPS. IF SOMETHING DOES DEVELOP...SEVERE THREAT LOOKS MARGINAL AS EFFECTIVE DEEP LAYER SHEAR WILL REMAIN WEAK AT 15 TO 25 KNOTS AT BEST. WILL KEEP MENTION OF SEVERE BUT WILL DECREASE MAX HAIL SIZE DOWN TO PENNY TO QUARTER SIZE. HOWEVER...AS THE EVENING PROGRESSES INTO THE OVERNIGHT HOURS A 30 TO 40 KT LLJ IS SHOWN TO NOSE INTO THE AREA WITH WHATEVER CONVECTION REMAINS ACROSS THE HIGH PLAINS SLIDING EAST INTO THE CWA. COVERAGE OF STORMS LOOKS SMALL...BUT WILL KEEP A SLIGHT CHANCE OVER MOST OF THE CWA THROUGH THE NIGHT. THURSDAY AFTERNOON INTO THURSDAY NIGHT IS THEN SHAPING UP TO BE AN ACTIVE TIME FRAME ACROSS THE REGION. A WEAK AREA OF LOW PRESSURE IS SHOWN BY THE MODELS TO SPIN UP OVER NORTH CENTRAL NEBRASKA WITH A WARM FRONT SEEN EXTENDING EAST ACROSS NORTHERN NEBRASKA WHILE A DRYLINE STRETCHES SOUTH ACROSS FAR WESTERN SECTIONS OF THE FORECAST AREA GENERALLY NEAR HIGHWAY 283. DEEP LOW LEVEL MOISTURE WILL BE AVAILABLE AHEAD OF THE DRYLINE AND ON EITHER SIDE OF THE WARM FRONT. THIS IS SHOWN TO PRODUCE ML CAPES OF 2000 TO 2500 J/KG NEAR THE DRYLINE AND 3000 TO 3500 J/KG NEAR THE WARM FRONT. A HEALTHY SHORT WAVE IS SHOWN TO RIDE OUT OF THE ROCKIES INTO THE PLAINS DURING THE AFTERNOON AND EXPECT THIS TO TRIGGER ISOLATED CONVECTIVE DEVELOPMENT ALONG THE DRYLINE AND MORE SCATTERED DEVELOPMENT JUST NORTH OF THE CWA NEAR THE WARM FRONT. SEVERE CONVECTION WISE...EFFECTIVE DEEP LAYER SHEAR WILL BE RATHER WEAK ALONG DRYLINE BY MID TO LATE AFTERNOON WITH VALUES OF 10 TO 25 KNTS AT BEST. THIS SHOULD KEEP CONVECTION ON THE WEAKER SIDE OVER THIS PORTION OF FORECAST AREA. HOWEVER...WITH SURFACE WINDS BACKING AROUND TO A MORE EASTERLY DIRECTION CLOSER TO THE WARM FRONT...EFFECTIVE DEEP LAYER SHEAR OF 25 TO NEAR 40 KNTS SHOULD SUPPORT GOOD CELL ORGANIZATION AND POSSIBLE ROTATION. TORNADO THREAT LOOKS MINIMAL BUT LARGE HAIL THREAT LOOKS POSSIBLE MAINLY NORTH OF HIGHWAY 92. TEMPERATURE WISE...A VERY WARM AFTERNOON LOOKS ON TAP WITH HIGHS RANGING FROM THE LOWER TO MID 90S NEAR ORD TO OSCEOLA...TO THE MID 90S TO AROUND 100 ACROSS NORTH CENTRAL KANSAS. LONG TERM...12Z FRIDAY THROUGH WEDNESDAY. A COLD FRONT WILL BE ON TOP OF THE CWFA FRIDAY MORNING...AS MAY LEFTOVER SHOWERS AND DEBRIS CLOUDS FROM ANY THURSDAY NIGHT MCS ACTIVITY. THE MODELS ARE ALL VERY SIMILAR IN TIMING THE FRONT THROUGH ALL BUT THE FAR SOUTHEAST CFWA AS EARLY AS MIDDAY...AND THAT MAY BE TOO SLOW IF CONVECTION THURSDAY NIGHT PUSHES HAS ANY SAY. POINT IS...WITH CLOUDS LINGERING...AND FRONT ON THE MOVE...THE BEST CHANCE FOR ANY PRECIPITATION FRIDAY WILL BE EAST/SOUTHEAST CWFA. KEPT A SMALL RISK FOR FRIDAY NIGHT...IN CASE POST FRONTAL ELEVATED PRECIPITATION CAN FORM...WHICH IT OFTEN DOES FOR A TIME IN THESE SITUATIONS. THE WEEKEND LOOKS ADMIRABLE WEATHER WISE. ANOMALOUSLY DRY AIR IS FORECAST TO COME INTO THE CENTRAL PLAINS BEHIND COLD FRONT FRIDAY...DRIVEN BY GREAT LAKES REGION LOW PRESSURE. PWAT VALUES ARE FORECAST TO BE IN THE LOWER HALF OF CLIMATOLOGY VALUES. THOUGH DEWPOINTS MAY BE HELD UP SLIGHTLY WITH EVAPOTRANSPIRATION AND RECENT RAINFALL ISSUES...IT SHOULD STILL FEEL MUCH MORE PLEASANT WITH DEWPOINTS IN THE 50S FOR MOST AREAS. NEXT SHOT FOR A STORM OR TWO COULD COME MONDAY EVENING IN THE WESTERN ZONES...AS A STORM MAY FLOUNDER IN FROM THE HIGH PLAINS. LITTLE BETTER RISK OF STORMS POSSIBLE TUESDAY/WEDNESDAY...AS THE RIPPLE EFFECT RETURNS WITH A WEAK WAVE CUTTING THROUGH THE RIDGE. TEMPERATURES SHOULD GRADUALLY WARM A FEW DEGREES EACH BEGINNING SATURDAY. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ HEINLEIN ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 355 PM CDT WED JUN 25 2008 .SHORT TERM...FOR TONIGHT THROUGH THURSDAY NIGHT. LATEST WATER VAPOR IMAGERY REVEALS A FAIRLY ZONAL FLOW REGIME ACROSS THE NORTHERN HALF OF THE CONUS WITH SEVERAL SMALL BUT POTENT WAVES EMBEDDED WITHIN THIS UPPER FLOW PATTERN. ONE OF THESE WAVES IS CURRENTLY SLIDING OUT OF THE HIGH PLAINS WHILE A SECOND WAVE IS SEEN PUSHING INTO THE ROCKIES. RECENT OBJECTIVE SURFACE ANALYSIS SHOWS TWO BOUNDARIES OF INTEREST ACROSS THE AREA WITH A DIFFERENTIAL HEATING BOUNDARY STRETCHING FROM NEAR MCCOOK TO AROUND GRAND ISLAND WHILE WEAK SURFACE TROUGH IS SEEN STRETCHING FROM NORTHERN IOWA INTO NORTH CENTRAL NEBRASKA. LOOKING AT RUC ANALYSIS...ML CAPES OF 3000 TO AS HIGH AS 4500 J/KG ARE SEEN FROM NORTHERN KANSAS INTO CENTRAL NEBRASKA ALTHOUGH MOST OF THIS AREA CONTINUES TO HAVE MODEST TO STRONG INHIBITION. HOWEVER...WEAKER INHIBITION IS SHOWN ACROSS NORTH CENTRAL NEBRASKA AND AGAIN ACROSS NORTHWESTERN KANSAS. TAKING A LOOK AT VISIBLE SAT IMAGERY IN THESE WEAKER INHIBITION AREAS...A SMALL CLUSTER OF CU IS VISIBLE NEAR KGLD BUT LITTLE IS SHOWN ACROSS NORTH CENTRAL NEBRASKA. MAIN QUESTION AS THE AREA HEADS INTO THIS EVENING TO OVERNIGHT IS WHERE DEEP CONVECTION MAY DEVELOP. INITIAL PROBLEM WITH DEVELOPING DEEP CONVECTION ACROSS THE AREA LATE THIS AFTERNOON TO EARLY EVENING IS THAT FORCING FROM THE FIRST WAVE MOVING THROUGH THE REGION NOW...IS SHOWN TO SLIDE EAST OF THE FORECAST AREA BY EARLY EVENING. GIVEN THE TIMING OF THIS WAVE PRODUCING INCREASING MID LEVEL SUBSIDENCE ALONG WITH A LACK OF ANY CONVECTIVE DEVELOPMENT OVER THE REGION THIS AFTERNOON...CONFIDENCE IS LOW THAT DEEP CONVECTION WILL DEVELOP THROUGH EARLY EVENING. WILL OPT TO KEEP A SLIGHT CHANCE OVER MOST OF THE CWA BUT THIS MAY NEED TO BE REMOVED BY THE EVENING SHIFT IF NOTHING DEVELOPS. IF SOMETHING DOES DEVELOP...SEVERE THREAT LOOKS MARGINAL AS EFFECTIVE DEEP LAYER SHEAR WILL REMAIN WEAK AT 15 TO 25 KNOTS AT BEST. WILL KEEP MENTION OF SEVERE BUT WILL DECREASE MAX HAIL SIZE DOWN TO PENNY TO QUARTER SIZE. HOWEVER...AS THE EVENING PROGRESSES INTO THE OVERNIGHT HOURS A 30 TO 40 KT LLJ IS SHOWN TO NOSE INTO THE AREA WITH WHATEVER CONVECTION REMAINS ACROSS THE HIGH PLAINS SLIDING EAST INTO THE CWA. COVERAGE OF STORMS LOOKS SMALL...BUT WILL KEEP A SLIGHT CHANCE OVER MOST OF THE CWA THROUGH THE NIGHT. THURSDAY AFTERNOON INTO THURSDAY NIGHT IS THEN SHAPING UP TO BE AN ACTIVE TIME FRAME ACROSS THE REGION. A WEAK AREA OF LOW PRESSURE IS SHOWN BY THE MODELS TO SPIN UP OVER NORTH CENTRAL NEBRASKA WITH A WARM FRONT SEEN EXTENDING EAST ACROSS NORTHERN NEBRASKA WHILE A DRYLINE STRETCHES SOUTH ACROSS FAR WESTERN SECTIONS OF THE FORECAST AREA GENERALLY NEAR HIGHWAY 283. DEEP LOW LEVEL MOISTURE WILL BE AVAILABLE AHEAD OF THE DRYLINE AND ON EITHER SIDE OF THE WARM FRONT. THIS IS SHOWN TO PRODUCE ML CAPES OF 2000 TO 2500 J/KG NEAR THE DRYLINE AND 3000 TO 3500 J/KG NEAR THE WARM FRONT. A HEALTHY SHORT WAVE IS SHOWN TO RIDE OUT OF THE ROCKIES INTO THE PLAINS DURING THE AFTERNOON AND EXPECT THIS TO TRIGGER ISOLATED CONVECTIVE DEVELOPMENT ALONG THE DRYLINE AND MORE SCATTERED DEVELOPMENT JUST NORTH OF THE CWA NEAR THE WARM FRONT. SEVERE CONVECTION WISE...EFFECTIVE DEEP LAYER SHEAR WILL BE RATHER WEAK ALONG DRYLINE BY MID TO LATE AFTERNOON WITH VALUES OF 10 TO 25 KNTS AT BEST. THIS SHOULD KEEP CONVECTION ON THE WEAKER SIDE OVER THIS PORTION OF FORECAST AREA. HOWEVER...WITH SURFACE WINDS BACKING AROUND TO A MORE EASTERLY DIRECTION CLOSER TO THE WARM FRONT...EFFECTIVE DEEP LAYER SHEAR OF 25 TO NEAR 40 KNTS SHOULD SUPPORT GOOD CELL ORGANIZATION AND POSSIBLE ROTATION. TORNADO THREAT LOOKS MINIMAL BUT LARGE HAIL THREAT LOOKS POSSIBLE MAINLY NORTH OF HIGHWAY 92. TEMPERATURE WISE...A VERY WARM AFTERNOON LOOKS ON TAP WITH HIGHS RANGING FROM THE LOWER TO MID 90S NEAR ORD TO OSCEOLA...TO THE MID 90S TO AROUND 100 ACROSS NORTH CENTRAL KANSAS. .LONG TERM...12Z FRIDAY THROUGH WEDNESDAY. A COLD FRONT WILL BE ON TOP OF THE CWFA FRIDAY MORNING...AS MAY LEFTOVER SHOWERS AND DEBRIS CLOUDS FROM ANY THURSDAY NIGHT MCS ACTIVITY. THE MODELS ARE ALL VERY SIMILAR IN TIMING THE FRONT THROUGH ALL BUT THE FAR SOUTHEAST CFWA AS EARLY AS MIDDAY...AND THAT MAY BE TOO SLOW IF CONVECTION THURSDAY NIGHT PUSHES HAS ANY SAY. POINT IS...WITH CLOUDS LINGERING...AND FRONT ON THE MOVE...THE BEST CHANCE FOR ANY PRECIPITATION FRIDAY WILL BE EAST/SOUTHEAST CWFA. KEPT A SMALL RISK FOR FRIDAY NIGHT...IN CASE POST FRONTAL ELEVATED PRECIPITATION CAN FORM...WHICH IT OFTEN DOES FOR A TIME IN THESE SITUATIONS. THE WEEKEND LOOKS ADMIRABLE WEATHER WISE. ANOMALOUSLY DRY AIR IS FORECAST TO COME INTO THE CENTRAL PLAINS BEHIND COLD FRONT FRIDAY...DRIVEN BY GREAT LAKES REGION LOW PRESSURE. PWAT VALUES ARE FORECAST TO BE IN THE LOWER HALF OF CLIMATOLOGY VALUES. THOUGH DEWPOINTS MAY BE HELD UP SLIGHTLY WITH EVAPOTRANSPIRATION AND RECENT RAINFALL ISSUES...IT SHOULD STILL FEEL MUCH MORE PLEASANT WITH DEWPOINTS IN THE 50S FOR MOST AREAS. NEXT SHOT FOR A STORM OR TWO COULD COME MONDAY EVENING IN THE WESTERN ZONES...AS A STORM MAY FLOUNDER IN FROM THE HIGH PLAINS. LITTLE BETTER RISK OF STORMS POSSIBLE TUESDAY/WEDNESDAY...AS THE RIPPLE EFFECT RETURNS WITH A WEAK WAVE CUTTING THROUGH THE RIDGE. TEMPERATURES SHOULD GRADUALLY WARM A FEW DEGREES EACH BEGINNING SATURDAY. && .AVIATION...FOR THE 18Z KGRI TAF. VFR TO MVFR CONDITIONS ANTICIPATED FOR THE GRAND ISLAND TERMINAL THROUGH THE NEXT 24 HOURS. THE MAIN FORECAST CONCERN WILL REVOLVE AROUND A CHANCE OF SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON TO EARLY THIS EVENING. APPEARS COVERAGE OF STORMS WILL BE HIGH ENOUGH TO WARRANT A MENTION IN THE FORECAST FOR THE THE TERMINAL AREA. OTHERWISE...EXPECT THREAT FOR STORMS TO SLIDE SOUTH OF THE TERMINAL BY MID TO LATE EVENING WITH VFR CONDITIONS EXPECTED THROUGH THURSDAY MORNING. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTH PLATTE NE 340 PM CDT TUE JUN 24 2008 .DISCUSSION... FORECAST FOCUS ON TEMPERATURES THE NEXT FEW DAYS...THUNDERSTORM CHANCES TONIGHT AND WEDNESDAY. LOW PRESSURE IN WY/SE MT AND THE FRONT RANGE. CONVECTION HAS ERUPTED BACK THERE WITH SOME CU NOW DEVELOPING ACROSS THE NEBRASKA PANHANDLE. RUC MODEL SOUNDINGS SHOW THE AREA NEARLY UNCAPPED LATE THIS AFTERNOON SO IT WON/T TAKE MUCH TO GET GOING THIS EVENING. AFTER LAST NIGHT/S STORMS NO OUTFLOW BOUNDARIES ARE APPARENT ATTM BUT MAY BECOME VISIBLE OVER THE NEXT HOUR. WEDNESDAY...TEMPERATURES FORECAST TO CROSS THE 90 MARK FOR MUCH OF THE AREA FOR THE FIRST TIME IN 2008 TOMORROW. MODELS AND MODEL SOUNDINGS LOOK MORE HOPEFUL FOR MORE THUNDERSTORM ACTIVITY ON WEDNESDAY. RAISED POPS A BIT FOR TOMORROW EVENING AND A GOOD THREAT FOR SEVERE TOMORROW NIGHT WITH JUST ENOUGH CAP TO HOLD THINGS IN PLACE FOR LATE AFTERNOON RELEASE WITH A FRONT WORKING INTO THE AREA. THURSDAY...A SECOND FRONT APPROACHES AND BRINGS ANOTHER CHANCE OF THUNDERSTORMS. FRIDAY AND SATURDAY...TEMPERATURES WILL BACK DOWN A FEW DEGREES AFTER THE PASSAGE OF A COLD FRONT. DEW POINTS DROP BACK AS WELL. LOOKING AT THE EXTENDED FORECAST SUNDAY THROUGH TUESDAY... IS CHARACTERIZED BY RIDGING AND A MUCH MORE AMPLIFIED PATTERN WITH A RIDGE ACROSS THE ROCKIES AND RESULTANT WARMING INTO THE 90S. AMPLIFIED PATTERN ALSO TO BRING DRIER CONDITIONS THROUGH MID WEEK. && .AVIATION... VFR CONDITIONS SHOULD DOMINATE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THROUGH THE NEXT 24 HOURS. CIGS HGHTS SHOULD BE AOA 120KFT AGL HOWEVER SOME CONVECTION MAY DEVELOP INTO THE WESTERN SANDHILLS AND PANHANDLE...WHERE CIGS HGHTS MAY DROP TO AROUND 5KFT NEAR THE STORMS...WHERE VSBYS MAY ALSO BE REDUCED TO AROUND 3 MILES IN THE RAIN SHOWERS. GUSTY WINDS AND ISOLATED LARGE HAIL WILL ALSO BE THREATS TO LIGHT AIRCRAFT NEAR THESE STORMS. A FRONT MOVING INTO THE CENTRAL PORTION OF NEBRASKA WILL LEAD TO ADDITIONAL CLOUD COVER ON WEDNESDAY WITH MAINLY VFR EXPECTED THROUGH THE EARLY AFTERNOON HOURS. && .LBF WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PHILLIPS/HIRSCH ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 313 PM CDT TUE JUN 24 2008 .DISCUSSION... DISTINCT MCV APPEARING IN SAT IMAGERY/RADAR LOOP IS AIDING TSRA DEVELOPMENT IN SERN NEB TODAY. SUBJECTIVE 12Z UPPER AIR ANALYSIS INDICATED WAVY ZONAL FLOW...WITH SHORTWAVE EVIDENT ACROSS ERN NEB/CTRL KS/WRN OK/TX PANHANDLE...AND ANOTHER UPSTREAM IN SRN AB/WRN MT/NRN ID. 850MB LOW WAS DIGGING INTO SRN NV...WITH BROAD MOISTURE AXIS ACROSS MUCH OF THE PLAINS. RICHER MOISTURE /12C+/ WAS LIMITED TO S CTRL TX AND NEAR KABR...AS WELL AS NEAR THE LOWER MS RIVER VALLEY. MCV THAT DEVELOPED IN WAKE OF MORNING MCS HAS MOVED INTO SWRN CWA...WITH TSRA DEVELOPING JUST AHEAD. SOME SUN IN SERN NEB HAS ALLOWED DESTABILIZATION TODAY AS TEMPS HAVE REACHED THE UPPER 70S WITH DEWPOINTS NEAR 70. MAIN FORECAST CONCERNS WILL BE WITH CONVECTION THIS EVNG...THEN CHCS FOR CONVECTION THROUGH FRI. RUC ANALYSIS INDICATES MLCAPE AROUND 1500 J/KG IN SERN NEB WITH NO CIN LIFT...WITH EFFECTIVE BULK SHEAR AROUND 30-35KT. APPEARS TO BE JUST ENOUGH SHEAR/INSTABILITY TO ALLOW ORGANIZED SURFACE-BASED CONVECTION WITH HAIL/WIND POTENTIAL. EXPECT ACTIVITY TO BE SUPPRESSED IN SUBSIDENT REGION BEHIND MCV...THUS TSRA POTENTIAL SHOULD DIMINISH LATER THIS EVENING FOR THE REST OF THE NIGHT. SHOULD SEE TSRA DEVELOPMENT TONIGHT IN SD AS SHORTWAVE MOVES ACROSS THE NRN PLAINS...BUT APPEARS THAT FORCING WILL REMAIN N OF THE CWA. MODELS AGREE IN DEVELOPING SFC LOW TMRW ACROSS WRN KS/ERN CO AS UPPER WAVE DIGS INTO NRN ROCKIES...WITH WARM FRONT SOLIDIFYING SOMEWHERE ACROSS NRN NEB/SRN SD. THAT SHOULD PROVIDE A FOCUS FOR TSRA DEVELOPMENT TMRW AFTN/EVNG AS INSTABILITY BUILDS. DEEP-LAYER SHEAR IS STILL RELATIVELY WEAK IN THE WARM SECTOR BUT SHOULD BE MARGINALLY ENOUGH NEAR/NORTH OF THE WARM FRONT TO SUPPORT ORGANIZED CONVECTION AGAIN...WITH RISKS OF HAIL/WINDS. BETTER SUPPORT FOR CONVECTION ARRIVES ON THURS AS WARM FRONT STALLS ACROSS THE AREA...WITH SRLY FLOW AT 850MB POINTING INTO THE FRONT AND SHORTWAVE MOVING ACROSS THE CTRL PLAINS. EXPECT EXACT LOCATION OF FRONT WILL DEPEND STRONGLY ON EFFECTS OF CONVECTION WED/WED NT...THUS DID NOT HIT ANY PARTICULAR AREA TOO HARD WITH POPS...BUT CERTAINLY POTENTIAL IS THERE FOR HEAVY RAIN THREAT WITH TRAINING THUNDERSTORMS ALONG BDRY. HEAVY RAIN/FLOOD THREAT WILL BE ENHANCED IF FRONTAL POSITION IS CLOSE TO TRACK OF TSRA ON WED/WED NT AS WELL. TEMPS IN THE WARM SECTOR BOTH WED AND THURS WILL CLIMB TO NEAR 90/LOWER 90S WITH SRLY FLOW AND DECENT HEATING. COLD FRONT WILL WORK THROUGH ERN NEB/WRN IA ON FRI AS NRN STREAM UPPER TROUGH DROPS OUT OF CANADA...KICKING SFC LOW EWD TOWARD THE GT LAKES/MS RIVER VALLEY. MADE FEW CHANGES TO DEPICTION FOR FRI WITH UNCERTAINTY ON POSITION OF COLD FRONT AFFECTING PRECIP POTENTIAL AS WELL AS TEMPS. NOT A STRONG COLD PUSH BEHIND THE FRONT...BUT CANADIAN AIRMASS SHOULD BE ENOUGH TO PUSH TEMPS BACK TO NEAR CLIMO FOR THE WEEKEND. SFC HIGH AND UPPER RIDGE BUILDING IN ON SAT/SUN SHOULD ALLOW A PLEASANT WEEKEND. RIDGE BEGINS TO BREAK DOWN EARLY NEXT WEEK WITH RIDGE-RIDING WAVES BRINGING ACTIVE WEATHER TO THE CTRL PLAINS AGAIN. TIMING THESE WAVES IS TOUGH AT LONG RANGE...BUT DID INCLUDE SCHC POPS FOR TUES AS MOISTURE RETURNS AND RIDGE WEAKENS. && .AVIATION... FOR TAF SITES KOMA...KLNK AND KOFK...THROUGH 25/18Z. WEAK WRMFNT EXTENDED FROM CNTRL MO THRU NRN KS. UPPER DISTURBANCE OVER ERN NEB KICKING OFF SCT +TSRA AFFECTING KOMA/KLNK. EXPECT ACTIVITY WILL BE FADING AFTER 00-03Z. THRU THEN...OCCASIONAL MVFR CONDITIONS SHOULD BE EXPECTED AT KOMA/KLNK. AFT 06Z...SMALL CHANCE FOR TS REDEVELOPMENT OVER SE NEB 00Z-06Z. AFTER 06Z...OTLK IS VFR THRU THE REST OF THE PD. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ MAYES/DEE ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 254 AM EDT TUE JUN 24 2008 .SYNOPSIS... A DEEP UPPER LEVEL TROUGH AND ASSOCIATED SURFACE FRONT WILL EXIT THE AREA TUESDAY MORNING. SURFACE HIGH PRESSURE WILL BUILD INTO THE STATE FROM OHIO AND TENNESSEE VALLEYS THROUGH WEDNESDAY. ABOVE NORMAL TEMPERATURES AND HIGH HUMIDITIES RETURN BY THE END OF THE WORK WEEK AS BERMUDA HIGH PRESSURE BUILDS OVER THE SOUTHEAST. && .NEAR TERM / THROUGH TONIGHT/... AS OF 230 AM TUESDAY... ISOLATED SHOWERS CONTINUE TO DEVELOP ACROSS THE FORECAST AREA THIS MORNING...IN RESPONSE TO THE IMPRESSIVE SHORTWAVE DYNAMICS...TRANSVERSING THE REGION THROUGH THE BASE OF THE AT THE BASE OF THE LONG WAVE TROUGH. FOR THE MOST PART HOWEVER...THESE SHOWERS ARE SHORT LIVED AS OUTFLOW BOUNDARIES FROM THE STORMS EARLIER IN THE EVENING...EFFECTIVELY STABILIZED THE AREA. THE LATEST RUC MOVES THROUGH THE UPPER LEVEL TROUGH AND ASSOCIATED SURFACE FRONT EAST OF THE AREA 10Z...ENDING THE CHANCE OF POPS ACROSS THE COASTAL PLAIN REGION. THE DEPARTURE OF THE UPPER TROUGH ALLOWS RISING HEIGHTS ALOFT WITH SURFACE RIDGING GRADUALLY BUILDING INTO THE AREA FROM OUT OF THE OHIO AND TN VALLEYS. THICKNESSES SUPPORT HIGHS IN THE UPPER 80S TO LOWER 90S...WITH MODEL SOUNDINGS INDICATING A HIGH LIKELIHOOD OF MIXING DOWN MUCH DRIER AIR TO THE SURFACE...WITH A MIXED LAYER AOA 750 MB AND 1000-850MB LAYER WINDS TURNING WESTERLY. WILL GO BELOW MODEL GUIDANCE...WITH DEWPOINTS DROPPING INTO THE UPPER 40S TO LOWER 50S THIS AFTERNOON. GOOD RADIATIONAL COOLING OVERNIGHT WITH RIDGING ALOFT AND SURFACE RIDGE EXTENDING EAST INTO THE AREA TO CREATE NEARLY CALM WINDS. OVERNIGHT MINS WILL DROP INTO THE LOWER TO MID 60S...SOME 3 TO 5 DEGREES BELOW CLIMATOLOGY. .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 230 AM TUESDAY... SUBTROPICAL RIDGE STRENGTHENS OVER THE SE CONUS THROUGH THE WEEK. FORECAST MODELS INCREASE LOW-LEVEL THICKNESSES IN THE UPPER RANGE OF 1430S WITH 850 TEMPERATURES RISING TO 19 TO 20 C. CLIMATOLOGICALLY THIS SUPPORTS HIGHS MODERATING INTO THE MID TO UPPER 90S WITH LOWS 65 TO 70. WITH CAPPING INVERSION ALOFT OVER THE AREA AND NO SOURCE FOR LIFT...CONVECTIVE DEVELOPMENT IS NOT LIKELY TO OCCUR. HOWEVER...IT CANNOT BE TOTALLY RULED OUT THAT A STRAY SHOWER OR TWO THAT INITIATES ALONG THE HIGHER TERRAIN WOULD NOT BE ABLE TO DRIFT INTO THE NW PIEDMONT ON THURSDAY. WILL KEEP AN ISOLATED POP IN THE NW PIEDMONT ONLY. && .LONG TERM /FRIDAY THROUGH MONDAY/... LITTLE CHANGE TO CURRENT FORECAST. SUNDAY WILL SEE THE BEST CHANCE FOR SHOWERS OR THUNDERSTORMS DURING THIS FORECAST PERIOD AS A BROAD MID AND UPPER LEVEL TROUGH APPROACHES FROM THE WEST. OTHERWISE RAIN CHANCES ARE EXPECTED TO BE SLIGHT AND DURING THE AFTERNOON AND EVENING FROM FRIDAY THROUGH SATURDAY. WITH SURFACE HIGH PRESSURE OFFSHORE UNTIL IT IS PUSHED EAST BY THE SUNDAY FRONT...TEMPERATURES WILL GENERALLY BE ABOVE NORMAL... WITH LOWS 68 TO 74 AND AFTERNOON HIGHS 87 TO 93. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 230 AM... AN ISOLATED SHOWER OR TWO BEFORE SUNRISE THIS MORNING. SOME LOCALIZED MVFR FOG UNTIL SHORTLY AFTER SUNRISE TODAY. OTHERWISE VFR CONDITIONS THROUGH THE TAF PERIOD WITH NO CONVECTION DURING THE DAYLIGHT HOURS. SURFACE HIGH PRESSURE WILL PROVIDE FOR VFR CONDITIONS THROUGH SATURDAY WITH THE EXCEPTION OF MVFR VISIBILITIES IN FOG DURING THE LATE NIGHT AND EARLY MORNING HOURS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL NEAR TERM...CBL SHORT TERM...CBL LONG TERM...RLH AVIATION...RLH nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TULSA OK 1022 AM CDT TUE JUN 24 2008 .DISCUSSION... AXIS OF CONVECTION FROM CENTRAL KANSAS THROUGH WESTERN OKLAHOMA HAS BEEN MAINTAINED WITHIN WEAK TROUGHING NOTED IN PROFILER WINDS AND RUC ANALYSIS. THIS FEATURE WILL SLOWLY SHIFT EASTWARD HOWEVER ANY IMPACTS ARE EXPECTED BE LATER TODAY KEEPING THE AFTERNOON DRY. TEMPERATURES HAVE QUICKLY WARMED THIS MORNING AND SHOULD HAVE NO PROBLEM REACHING THE FORECAST HIGHS. UPDATED FORECAST WILL ADJUST FOR OBSERVED TRENDS WITH OVERALL CHANGES BEING SMALL. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...07 LONG TERM....21 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 742 AM EDT TUE JUN 24 2008 .SYNOPSIS... A TROUGH OF LOW PRESSURE WILL DIVE SOUTH ACROSS EASTERN PENNSYLVANIA TODAY. HIGH PRESSURE WILL BUILD OVER THE COMMONWEALTH TONIGHT AND WEDNESDAY. A WARM FRONT WILL PUSH THROUGH THE REGION EARLY THURSDAY. A SHARP COLD FRONT WILL LIKELY SWEEP THROUGH THE STATE SATURDAY NIGHT OR SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LIGHT WIND/CLEARING SKY AND RECENT RAINFALL RESULTING IN PATCHY FOG EARLY THIS MORNING EAST OF THE MTNS. WHERE MOIST LL FLOW ASCENDING THE MTNS...LOW STRATUS HAS FORMED OVR THE ALLEGHENIES WITH LOCALLY DENSE FOG LIKELY ON THE RIDGETOPS. LATEST RUC13 RH INDICATES THE MOST PERSISTENT LOW CLOUDS/FOG OVR THE ALLEGHENIES WILL BURN OFF BY ARND 14Z. WATER VAPOR LOOP SHOWING NEXT SHORTWAVE DIVING SOUTHWARD ACROSS EASTERN ONTARIO. LARGE SCALE LIFT ASSOCIATED WITH THIS FEATURE APPEARS TO BE WEAK BASED ON LACK OF SIG DOWNSTREAM PRES FALLS. HOWEVER...IT/S POOL OF COLD AIR ALOFT IS EXPECTED TO COMBINE WITH STRONG DIURNAL HEATING TO RESULT IN STEEP LAPSE RTS BY MIDDAY. SREF DATA INDICATES MODEST CAPE VALUES NR 500 J/KG ACROSS EASTERN PA FROM LATE AM THRU LATE AFTN...WHERE A FEW TSTMS MAY FORM. GIVEN COLD TEMPS ALOFT...CAN/T RULE OUT SMALL HAIL WITH ANY STORMS. WILL LEAN SLIGHTLY HIGHER THAN MOS POPS FROM ARND IPT NORTHWRD...WHERE LATEST SREF DATA SUGGESTS 30 POPS WARRANTED. MODEL 850 TEMPS ARND 12C SHOULD SUPPORT HIGHS FROM M70S HIGH TERRAIN...TO LOW 80S SUSQ VALLEY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... WILL NOT CARRY CHC OF SHWRS/TSTMS INTO THE EVENING HOURS...AS STRONG SUBSIDENCE IN WAKE OF DEPARTING SHORTWAVE SHOULD RESULT IN CRUMBLING CU BY 00Z. SFC RIDGE BUILDS INTO THE REGION TONIGHT ACCOMPANIED BY SEASONABLY DRY AIRMASS...WHICH SHOULD ALLOW FOR DECENT RADIATIONAL COOLING UNDER MCLEAR SKIES/LIGHT WIND. A BIT OF AM VALLEY FOG APPEARS POSSIBLE IN THE DEEP RIVER/STREAM VALLEYS OF THE NORTH EARLY WED AM. USUALLY A 25F OR GREATER DIFF BTWN AIR TEMPS AND WATER TEMP IS NEEDED...WHICH APPEARS LIKELY GIVEN WATER TEMPS IN THE L-M70S. RETURN SW FLOW WILL ADVECT WARMER AIR INTO CENTRAL PA ON WED AS SFC RIDGE PASSES OFF THE COAST. SREF 850 TEMPS RISE TO ARND 14C...INDICATING HIGHS FROM U70S ALLEGHENIES...TO M80S SUSQ VALLEY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... WED NITE THROUGH FRI WILL BRING ZONAL FLOW ALOFT WHILE SURFACE HIGH PRESSURE HANGS OVER SOUTHEAST CONUS. A WARM FRONT WILL SLIP IN FROM THE OHIO VALLEY THU INTO FRI...BRINGING NEXT CHANCE FOR SHOWERS/TSTORMS...POSSIBLY AS EARLY AS LATE WED NIGHT IN THE FORM OF AN MCS. SCATTERED TSTMS WILL BE AROUND THU INTO FRI AS WE SLIP INTO WARM SECTOR AHEAD OF APPROACHING SYSTEM. WRAPPED UP SYSTEM MOVES IN FOR THE WEEKEND WITH SLOW MOVING SEMI- OCCLUDED COLD FRONT WELL OUT AHEAD OF MAIN UPPER LOW ON SAT. THIS WILL KEEP A DAILY CHANCE/SCATTERED TSTMS IN THE FORECAST SAT INTO SUN. PWATS INCREASE DURING THIS PERIOD AND COULD EVEN SEE SOME SHOWERS CONTINUE THROUGH THE NIGHT SAT. UPPER LOW FINALLY SLIDES THROUGH TO OUR NORTH ALONG WITH MAIN DYNAMICS LATER SUN INTO MON. PRECIP CHANCES DROP QUICK HEADED INTO MONDAY...AND A DRIER PERIOD WILL BEGIN AS BROAD RIDGE BUILDS OVER THE CENTRAL U.S. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... BNDRY LYR MOISTURE HAS PRODUCED A DECENT STRATUS LYR MAINLY ALONG THE ALLEGHENIES AND LAUREL HIGHLANDS STRETCHING NW ACROSS THE NW MOUNTAINS. IR IMAGERY INDICATED KJST/KUNV/KBFD/KIPT SOLIDLY IN THE BKN/OVC AND CIGS AOA 1500FT. ELSEWHERE KAOO WAS ON THE CUSP OF THE STRATUS LAYER AND CLOUDS COULD SPILL OVER THE RIDGE TOPS ARND 13Z AND PRODUCE A BKN/OVC CIG TEMPO. KMDT WILL MOST LIKELY REMAIN TOO FAR EAST AND WITH SFC HEATING THSI SHUD HELP PREVENT STRATUS FROM INVADING KMDT. POST SUNRISE FLOW WILL SHIFT TO W/NW AS MIX- LVL TROUGH AXIS SLIDES EAST. MIXED HGT ACROSS CENTRAL PA THIS AFTN WILL TOP OUT ARND 4KFT. ENUF LINGERING MOISTURE AND MINIMAL LIFT MAY PRODUCE A CU FIELD WITH CIGS ARND 4-5KFT AND VFR CONDS. MIXED HGT WILL TAP WINDS OF 15-20KTS...FILTERED DOWN TO THE SFC WILL RESULT IN GUSTS UP 12-15KTS THIS AFTN. AFTN INSTABILITY WILL BE MARGINAL AND COULD POP A FEW SHRA/TSRA...BUT EXPECT THIS WOULD OCCUR IN THE FAVORED UPSLOPE REGIONS OF THE ALLEGHENIES AND LAUREL HIGHLANDS. AN ISO SHRA/TSRA FURTHER EAST CAN/T BE RULED OUT CLOSER TO TROUGH AXIS IN EASTERN PA. SFC HIGH PRESSURE SLIDES IN WED/THUR AND SAGS CENTER SOUTH FRI. VFR CONDS EXPECTED WED/THUR AND POTENTIAL FOR SHRA/TSRA IN A MID- LVL WESTERLY FLOW THUR EVE/FRI/SAT. WEST-EAST ZONAL FLOW REGIME HEADING INTO THE WEEKEND WILL KEEP THINGS FLUID AND ACTIVE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...FITZGERALD NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD LONG TERM...RXR AVIATION...BEACHLER pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 859 PM CDT WED JUN 25 2008 .UPDATE... SCT TSRA...SVR AT TIMES...ARE MOVING INTO FAR SW SD ATTM...ASSOCIATED WITH AN ADVANCING WARM FRONT/SFC TROF LIFTING INTO THE WRN SD. MSAS SHOWS SFC HIGH PRESSURE SITTING OVER THE ERN DAKOTAS...AND MOISTURE DEPRIVED KABR 00Z SOUNDING INDICATES THAT NOTHING SHOULD LIFT THIS FAR NE OVERNIGHT. THE LATEST NAM12 DOES SHOW STRONG UPPER LEVEL DIVERGENCE SKIRTING ALONG OUR SRN COUNTIES TONIGHT. WITH WATCH THAT HAS BEEN ISSUED THROUGH 09Z FOR THE FAR SW COUNTIES...DID ADD MENTION OF SEVERE TO WORDING FOR THOSE COUNTIES OVERNIGHT. OTW REMAINDER OF ZONES LOOKED GOOD AND NO EDITING REQUIRED. UPDATED AVIATION DISCUSSION BELOW. && .PREV DISCUSSION... .SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW WEAK UPPER LEVEL RIDGING ACROSS THE WESTERN HIGH PLAINS. SKIES ARE MOSTLY CLEAR ACROSS THE CWA WITH INCREASING CLOUDS OVER WYOMING AS A WEAK DISTURBANCE IS MOVING THROUGH THAT AREA. THIS SYSTEM IS EXPECTED TO SLIDE ACROSS THE NORTHERN PLAINS OVERNIGHT AND BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS TO MAINLY THE SOUTHERN CWA. LLJ SETS UP OVERNIGHT ACROSS WESTERN SOUTH DAKOTA AND EXPECT THIS IS WHERE ANY ACTIVITY WILL BEGIN. MODELS AGREE FAIRLY WELL IN SHOWING SOME FORM OF WEAK MESOSCALE SYSTEM MOVING ACROSS THE SOUTHERN PORTION OF THE STATE OVERNIGHT ALONG NOSE OF LLJ. DIFFERENCES SHOW UP IN JUST HOW FAR NORTH COMPLEX WILL DEVELOP...AND HOW LONG IT LASTS INTO THURSDAY...IF AT ALL. FOR NOW HAVE KEPT LOW CHANCE POPS ACROSS THE SOUTHEASTERN CWA FOR THURSDAY TO ACCOUNT FOR ANY ACTIVITY THAT PERSISTS THROUGH THE FIRST HALF OF THE DAY. FOCUS THEN SHIFTS TO LATE THURSDAY AND ESPECIALLY THURSDAY NIGHT. LOTS OF THINGS TO CONSIDER WITH SVR POTENTIAL AND MAX HIGHS. IF THUNDERSTORM COMPLEX PANS OUT AND MOVES ACROSS THE STATE THURSDAY MORNING...DEBRIS CLOUD COVER AND RAIN COOLED AIR WILL PROBABLY PREVENT HIGHS FROM REACHING CURRENT FORECAST. CLOUD COVER COULD ALSO SUPPRESS INSTABILITY ACROSS EAST CENTRAL SOUTH DAKOTA. BUT...STILL EXPECTING THIS COMPLEX TO BE EAST OF THE AREA BY TOMORROW AFTERNOON SO THERE SHOULD STILL BE ENOUGH TIME FOR INSTABILITY RECOVERY. THERE WILL PROBABLY ALSO BE OLD OUTFLOW BOUNDARIES TO CONTEND WITH DURING THE DAY TOMORROW WHICH MAY PROVIDE FOCUS FOR CONVECTION LATER IN THE AFTERNOON. MODELS SHOWING BEST PRECIP CHANCES ACROSS THE CWA OVERNIGHT IN ASSOCIATION WITH THE LLJ. SVR PARAMETERS RATHER SUPPORTIVE OF STRONG CONVECTION...ESPECIALLY ACROSS THE SOUTHERN PORTION OF THE CWA. SYSTEM EXITS THE AREA FRIDAY AND HAVE LEFT SMALL CHANCE POPS ACROSS THE NORTHEAST ON THE BACK SIDE OF THE LOW. POSSIBILITY EXISTS TO SEE A FEW WRAP AROUND INSTABILITY SHOWERS ACROSS THE EXTREME NORTHEASTERN PORTION OF THE AREA. .LONG TERM...SATURDAY THROUGH WEDNESDAY GOOD AGREEMENT WITH THE MODELS AND GFS ENSEMBLES THROUGH THE LONG TERM. THE PERIOD BEGINS WITH A LARGE UPPER LOW/TROUGH JUST OFF TO OUR EAST SLOWLY BUILDING ACROSS THE EASTERN US THROUGH MONDAY WHILE A SHARP 50H RIDGE ACROSS THE WESTERN US MOVES SLOWLY EAST TOWARDS OUR REGION. SATURDAY SHOULD HAVE BELOW NORMAL TEMPERATURES AS COOL AIR CONTINUES TO POUR ACROSS THE REGION BEHIND THE EXITING SURFACE LOW PRESSURE AREA. CURRENT FORECAST TEMPERATURES MAY HAVE TO BE LOWERED EVEN MORE. ALSO...MAY SEE SOME CAA CU AND ISOLD/SCT -SHRAS ACROSS NORTHEAST SD AND WEST CENTRAL MN DURING THE DAY AND EARLY EVENING HOURS ON SATURDAY. OTHERWISE...MOST OF THE EXTENDED LOOKS DRY AS THE UPPER LEVEL RIDGE OUT WEST BUILDS SLOWLY INTO THE REGION AND FLATTENS OUT SOME BY THE MIDDLE OF THE WEEK. EXPECT MOSTLY CLEAR SKIES DURING THIS TIME WITH A WARM UP AS HEIGHTS INCREASE. SHOULD HAVE QUITE A BIT OF UPPER 80S AND LOWER 90S BY MONDAY AND TUESDAY ACROSS THE CWA. INDICATIONS ARE THAT THE RIDGE WILL BREAK DOWN SOME BY TUESDAY NIGHT AND WEDNESDAY WITH A SHORT WAVE COMING INTO THE REGION. THUS...HAVE IN CHANCES OF TSRAS DURING THIS TIME. && .AVIATION... VFR CONDS EXPECTED THROUGH 18Z FOR ALL TERMINAL SITES. SOME ISOLD/SCT TSRA MAY DEVELOP AND MOVE SOUTH OF THE KPIR TERMINAL...CLOSER TO I-90...AFT 06Z...WITH LITTLE IMPACT THOUGH AT THE KPIR TERMINAL. LOOK FOR INCREASING WINDS AFT 15Z FOR ALL TERMINAL SITES AS WELL. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...HINTZ SHORT TERM...TMT LONG TERM...MOHR AVIATION...HINTZ WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 333 PM CDT WED JUN 25 2008 .SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW WEAK UPPER LEVEL RIDGING ACROSS THE WESTERN HIGH PLAINS. SKIES ARE MOSTLY CLEAR ACROSS THE CWA WITH INCREASING CLOUDS OVER WYOMING AS A WEAK DISTURBANCE IS MOVING THROUGH THAT AREA. THIS SYSTEM IS EXPECTED TO SLIDE ACROSS THE NORTHERN PLAINS OVERNIGHT AND BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS TO MAINLY THE SOUTHERN CWA. LLJ SETS UP OVERNIGHT ACROSS WESTERN SOUTH DAKOTA AND EXPECT THIS IS WHERE ANY ACTIVITY WILL BEGIN. MODELS AGREE FAIRLY WELL IN SHOWING SOME FORM OF WEAK MESOSCALE SYSTEM MOVING ACROSS THE SOUTHERN PORTION OF THE STATE OVERNIGHT ALONG NOSE OF LLJ. DIFFERENCES SHOW UP IN JUST HOW FAR NORTH COMPLEX WILL DEVELOP...AND HOW LONG IT LASTS INTO THURSDAY...IF AT ALL. FOR NOW HAVE KEPT LOW CHANCE POPS ACROSS THE SOUTHEASTERN CWA FOR THURSDAY TO ACCOUNT FOR ANY ACTIVITY THAT PERSISTS THROUGH THE FIRST HALF OF THE DAY. FOCUS THEN SHIFTS TO LATE THURSDAY AND ESPECIALLY THURSDAY NIGHT. LOTS OF THINGS TO CONSIDER WITH SVR POTENTIAL AND MAX HIGHS. IF THUNDERSTORM COMPLEX PANS OUT AND MOVES ACROSS THE STATE THURSDAY MORNING...DEBRIS CLOUD COVER AND RAIN COOLED AIR WILL PROBABLY PREVENT HIGHS FROM REACHING CURRENT FORECAST. CLOUD COVER COULD ALSO SUPPRESS INSTABILITY ACROSS EAST CENTRAL SOUTH DAKOTA. BUT...STILL EXPECTING THIS COMPLEX TO BE EAST OF THE AREA BY TOMORROW AFTERNOON SO THERE SHOULD STILL BE ENOUGH TIME FOR INSTABILITY RECOVERY. THERE WILL PROBABLY ALSO BE OLD OUTFLOW BOUNDARIES TO CONTEND WITH DURING THE DAY TOMORROW WHICH MAY PROVIDE FOCUS FOR CONVECTION LATER IN THE AFTERNOON. MODELS SHOWING BEST PRECIP CHANCES ACROSS THE CWA OVERNIGHT IN ASSOCIATION WITH THE LLJ. SVR PARAMETERS RATHER SUPPORTIVE OF STRONG CONVECTION...ESPECIALLY ACROSS THE SOUTHERN PORTION OF THE CWA. SYSTEM EXITS THE AREA FRIDAY AND HAVE LEFT SMALL CHANCE POPS ACROSS THE NORTHEAST ON THE BACK SIDE OF THE LOW. POSSIBILITY EXISTS TO SEE A FEW WRAP AROUND INSTABILITY SHOWERS ACROSS THE EXTREME NORTHEASTERN PORTION OF THE AREA. .LONG TERM...SATURDAY THROUGH WEDNESDAY GOOD AGREEMENT WITH THE MODELS AND GFS ENSEMBLES THROUGH THE LONG TERM. THE PERIOD BEGINS WITH A LARGE UPPER LOW/TROUGH JUST OFF TO OUR EAST SLOWLY BUILDING ACROSS THE EASTERN US THROUGH MONDAY WHILE A SHARP 50H RIDGE ACROSS THE WESTERN US MOVES SLOWLY EAST TOWARDS OUR REGION. SATURDAY SHOULD HAVE BELOW NORMAL TEMPERATURES AS COOL AIR CONTINUES TO POUR ACROSS THE REGION BEHIND THE EXITING SURFACE LOW PRESSURE AREA. CURRENT FORECAST TEMPERATURES MAY HAVE TO BE LOWERED EVEN MORE. ALSO...MAY SEE SOME CAA CU AND ISOLD/SCT -SHRAS ACROSS NORTHEAST SD AND WEST CENTRAL MN DURING THE DAY AND EARLY EVENING HOURS ON SATURDAY. OTHERWISE...MOST OF THE EXTENDED LOOKS DRY AS THE UPPER LEVEL RIDGE OUT WEST BUILDS SLOWLY INTO THE REGION AND FLATTENS OUT SOME BY THE MIDDLE OF THE WEEK. EXPECT MOSTLY CLEAR SKIES DURING THIS TIME WITH A WARM UP AS HEIGHTS INCREASE. SHOULD HAVE QUITE A BIT OF UPPER 80S AND LOWER 90S BY MONDAY AND TUESDAY ACROSS THE CWA. INDICATIONS ARE THAT THE RIDGE WILL BREAK DOWN SOME BY TUESDAY NIGHT AND WEDNESDAY WITH A SHORT WAVE COMING INTO THE REGION. THUS...HAVE IN CHANCES OF TSRAS DURING THIS TIME. && .AVIATION... VFR SKIES ARE EXPECTED THROUGH THE DAY...NIGHT AND MORNING THURSDAY WITH ONLY SOME SCT MID AND HIGH LEVEL CLOUDS AOA 8000 FEET. WILL HAVE TO WATCH THE PIR AND ATY AREAS TONIGHT AND EARLY THURSDAY FOR POSSIBLE THUNDERSTORM DEVELOPMENT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...TMT LONG TERM...MOHR AVIATION...MOHR WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 1035 AM MDT TUE JUN 24 2008 .DISCUSSION...SATELLITE SHOWS MOSTLY SUNNY SKIES ACROSS THE FORECAST AREA AS AN MCS EXITS THE REGION TO THE EAST. WATER VAPOR SHOWS AN UPPER LOW NEAR THE CENTRAL MONTANA/CANADIAN BORDER MOVING EASTWARD TOWARD NORTH DAKOTA. WV IMAGERY ALSO HINTS AT A SECOND SHORTWAVE MOVING ACROSS NORTH CENTRAL WYOMING AT THIS TIME. THIS WILL LIKELY PLAY A BIG PART IN CONVECTIVE DEVELOPMENT THIS AFTERNOON. THIS WAVE WILL MOVE NEAR THE SD/WY BORDER BY MID AFTERNOON WHEN STORMS WILL BEGIN FIRING OVER THE HILLS BEFORE MOVING OFF OR REDEVELOPING ON THE PLAINS. LATEST RUC SHOWS VERY STRONG INSTABILITY TODAY WITH CAPE VALUES FROM 2000 TO 3000 J/KG...OR EVEN MORE IN SOME SPOTS WHICH LOOKS REASONABLE CONSIDERING MANY OBS ARE SHOWING DEWPOINTS IN THE 60S...AS HIGH AS 66 IN KPHP AT 16Z. ALSO THE CAP LOOKS TO BE PRETTY WEAK TODAY...SO IT SHOULDNT TAKE MUCH EFFORT FOR UPDRAFTS REACH LFC HEIGHTS. SURFACE OBS SHOW A TROUGH STRETCHED OUT ACROSS THE CWA WHICH WILL NOT MOVE MUCH UNTIL THIS EVENING. ALSO...REMNANT OUTFLOW BOUNDARIES FROM LAST NIGHTS STORMS ARE ALSO APPARENT INCLUDING ACROSS SOUTH CENTRAL SD. HAVE ADDED POPS FOR THAT AREA THIS AFTERNOON DESPITE THE LACK OF UPPER LEVEL SUPPORT SINCE IT LOOKS LIKE THE WAVE WILL CROSS MORE NORTH OF INTERSTATE 90. SHEAR PROFILES ALSO APPEAR WEAKER ACROSS SOUTH CENTRAL SD...BUT WITH CAPE VALUES NEAR 3000 J/KG...LITTLE CIN AND OLD OUTFLOW BOUNDARIES PRESENT...HAVE ADDED POPS FOR THE AFTERNOON HOURS. && .PREVIOUS DISCUSSION [325 AM MDT]...CURRENT SURFACE ANALYSIS HAS LOW PRESSURE OVER NORTH CENTRAL WY AND CENTRAL MT...WITH WEAK COLD FRONT STRETCHING SOUTHWESTWARD INTO THE GREAT BASIN. NUMEROUS SURFACE BOUNDARIES LIE ACROSS THE NORTHERN AND CENTRAL PLAINS...MOSTLY DUE TO EARLIER CONVECTION. UPPER LEVEL ANALYSIS SHOWS NEARLY FLAT ZONAL FLOW OVER MUCH OF THE NORTHERN CONUS. SHOWERS AND STORMS HAVE FINALLY DISSIPATED ACROSS THE AREA...WITH SKIES CLEARING FROM WEST TO EAST. TEMPS ARE IN THE 50S AND LOWER 60S WITH LIGHT WINDS. ACTIVE WX PATTERN TO CONTINUE FOR THE NEXT SEVERAL DAYS AS ZONAL FLOW ALOFT BRINGS A PARADE OF SHORTWAVES ACROSS THE REGION. TIMING OF THESE WAVES WILL CONTINUE TO BE DIFFICULT...BUT BETTER CHANCES FOR STORMS WILL CONTINUE TO BE DURING THE AFTERNOON AND EVENING HOURS...WHEN SOME OF THEM WILL BE SEVERE. TEMPS WILL BE ABOVE AVERAGE FOR THE NEXT FEW DAYS...WITH HIGHS MOSTLY IN THE 80S. FOR TODAY...SKIES WILL START OFF MOSTLY SUNNY FOR THIS MORNING INTO EARLY AFTERNOON. THE WEAK COLD FRONT TO THE WEST WILL APPROACH NORTHERN AND WESTERN PORTIONS OF THE CWA BY MID AFTERNOON...ALONG WITH A SHORTWAVE THAT IS MOVING ACROSS WESTERN MT NOW. STORMS SHOULD BEGIN TO FIRE ACROSS NORTHEAST WY AND FAR EASTERN MT IN THE AFTERNOON AND THEN MOVE EAST WITH THE FRONT. ADDITIONAL STORMS MAY FIRE OVER THE BLACK HILLS BY MID AFTERNOON. SURFACE LOW ALONG FRONT WILL CONSOLIDATE OVER EASTERN MT AND MOVE SLOWLY EAST-SOUTHEAST INTO SOUTHWEST ND/NORTHWEST SD BY EVENING. THREAT FOR SEVERE STORMS IS EXPECTED ACROSS THE ENTIRE AREA...WITH BEST THREAT BEING FROM THE BLACK HILLS AREA INTO NORTHWEST AND WEST CENTRAL SD. MODERATE INSTABILITY WILL BE PRESENT AHEAD OF FRONT WITH STEEP MID LEVEL LAPSE RATES. ANY CAP IN PLACE WILL ERODE BY MID TO LATE AFTERNOON IN THESE AREAS. MAIN THREATS WILL BE LARGE HAIL AND STRONG WIND GUSTS...BUT AN ISOLATED TORNADO IS ALSO POSSIBLE NEAR SURFACE LOW OVER NORTHWEST SD LATE THIS AFT/EARLY EVE. HIGH TEMPS WILL MOSTLY BE IN THE 80S...WITH SOME LOWER 90S ACROSS FAR SOUTHWESTERN SD. STORMS WILL MOVE EAST TONIGHT WITH COOL FRONT...WITH MAIN ACTIVITY OUT OF THE AREA AROUND MIDNIGHT. HOWEVER...WILL KEEP SOME LOW POPS IN PLACE FOR MOST OF THE AREA OVERNIGHT AS WEAK UPPER LEVEL ENERGY AND INSTABILITY COULD PRODUCE A FEW SHOWERS OR STORMS. WEDNESDAY AND THURSDAY WILL BE SIMILAR TO TODAY...WITH WARM TEMPERATURES AND A CONTINUED CHANCE FOR STORMS. HIGH TEMPS EACH DAY WILL BE IN THE 80S AND LOWER 90S...A BIT WARMER ON THURSDAY AHEAD OF A FAIRLY STRONG COLD FRONT. THE ENTIRE CWA IS IN THE SLIGHT RISK AREA FOR SEVERE STORMS ON WEDNESDAY AND THURSDAY. HOWEVER...IT LOOKS LIKE THURSDAY COULD BE THE MORE ACTIVE DAY AS FRONT APPROACHES THE AREA DURING PEAK HEATING. POTENTIAL EXISTS FOR LONG-LIVED SEVERE STORMS LATE THURSDAY INTO THURSDAY NIGHT. EXTENDED...POTENT SHORTWAVE WILL DIVE INTO EASTERN MONTANA EARLY FRIDAY MORNING AND SWEEP ACROSS THE CWA FRIDAY AFTERNOON. EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS WESTERN PORTIONS OF THE CWA FRIDAY MORNING...SPREADING EASTWARD INTO FRIDAY AFTERNOON. A RIDGE WILL BEGAN TO BUILD OVER THE AREA EARLY NEXT WEEK BRINGING DRY CONDITIONS AND MUCH WARMER TEMPERATURES TO THE AREA. TEMPERATURES WILL CLIMB INTO THE LOWER 90S BY EARLY NEXT WEEK AS THE RIDGE SETTLES OVER THE AREA. && .AVIATION...SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AND PERSIST INTO THIS EVENING WITH LOCAL MVFR CONDITIONS. OTHERWISE VFR CONDITIONS EXPECTED. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ CALDERON sd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AMARILLO TX 1126 PM CDT WED JUN 25 2008 .AVIATION... VFR CONDITIONS WILL PREVAIL AT ALL THREE TAF SITES THROUGH THURSDAY EVENING. NORTHWESTERLY FLOW ALOFT MAY BRING SOME CONVECTION INTO THE PANHANDLES THURSDAY AFTERNOON AND EVENING...HOWEVER DECIDED TO LEAVE OUT OF TAF PACKAGE FOR NOW AS CONFIDENCE LOW. CONVECTION MAY NOT AFFECT ANY OF TAF SITES SIMILAR TO THIS EVENING. WILL LET LATER SHIFTS INTRODUCE CONVECTION AS NEEDED. OTHERWISE...SOUTHERLY WINDS WILL INCREASE THURSDAY INTO THE 15 TO 25 KNOT RANGE. SCHNEIDER && .PREV DISCUSSION... /ISSUED 950 PM CDT WED JUN 25 2008/ UPDATE... CONVECTION DISSIPATING ACROSS THE REGION. APPEARS THE THREAT FOR STORMS IS DIMINISHING FOR THE PANHANDLES. RUC AND NAM DO SUGGEST THAT AN ISOLATED STORM MAY STILL DEVELOP OVERNIGHT. SO LOWERED POPS TO SLIGHT CHANCE THROUGH 12Z. JJB PREV DISCUSSION... /ISSUED 621 PM CDT WED JUN 25 2008/ AVIATION... CONVECTION EXPECTED TO AFFECT MAILY THE GUYMON AND DALHART TAF SITES THIS EVENING...AND MAY POSSIBLY AFFECT THE AMARILLO TAF SITE LATER THIS EVENING IF THEY CONTINUE TO HOLD TOGETHER AFTER SUNSET. OTHERWISE...SOUTH TO SOUTHWEST WINDS AROUND 10 TO 15 KNOTS TONIGHT WILL INCREASE THURSDAY MORNING TO 15 TO 25 KNOTS THROUGH THURSDAY AFTERNOON. VFR CONDITIONS WILL PERSIST WITH ONLY FEW TO SCATTERED CUMULUS AND SCATTERED TO BROKEN HIGH CLOUDS EXPECTED. SCHNEIDER PREV DISCUSSION... /ISSUED 224 PM CDT WED JUN 25 2008/ DISCUSSION... THUNDERSTORMS HAVE DEVELOPED EARLY THIS AFTERNOON ACROSS THE MOUNTAINS OF NEW NEW MEXICO...SOUTHERN COLORADO AND ALONG A SURFACE TROUGH THROUGH NORTHEAST NEW MEXICO. THESE STORMS SHOULD AGAIN MOVE SOUTHEAST LATE THIS AFTERNOON AND TONIGHT ACROSS MUCH OF THE PANHANDLES IN A NORTHWEST FLOW ALOFT. DO NOT SEE MUCH CHANGE IN THE PATTERN THROUGH THIS FORECAST. RIDGING WILL CONTINUE ACROSS THE SOUTHERN AND CENTRAL ROCKIES AND UPPER LEVEL TROUGHING WILL BE FOUND ACROSS THE EASTERN HALF OF THE U.S. A STRONG UPPER LEVEL LOW PRESSURE SYSTEM WILL DIVE SOUTHEAST INTO NORTHERN MINNESOTA BY FRIDAY WHICH WILL HELP TO DRIVE A COLD FRONT THROUGH THE PANHANDLES BY EARLY SATURDAY MORNING. THIS FRONT WILL BE ANOTHER FOCUS FOR THUNDERSTORM DEVELOPMENT BESIDES THE MOUNTAINS...SO CHANCES FOR STORMS MAY BE A LITTLE ENHANCED. THE NORTHWEST FLOW ACROSS THE PANHANDLES WILL INCREASE SOME AS THE UPPER LEVEL TROUGH GETS CARVED OUT OVER THE EASTERN HALF OF THE U.S. AND THE RIDGE STAYS PUT OVER THE ROCKIES. THIS WILL KEEP THE THREAT OF AFTERNOON AND NIGHTTIME THUNDERSTORMS GOING ACROSS THE PANHANDLES INTO MID NEXT WEEK. LOW LEVEL MOISTURE AND THE INSTABILITY WILL NOT BE GOING ANYWHERE THROUGH THIS FORECAST...SO SEVERE THUNDERSTORMS AND LOCALLY HEAVY RAINFALL WILL CONTINUE TO BE THREATS. FIRE WEATHER... LIGHTNING WILL BE A THREAT FOR STARTING WILDFIRES. BUT...WITH THE MOISTURE IN PLACE AND LIGHTER WINDS THE OVERALL WILDFIRE DANGER WILL BE LOW THROUGH THIS FORECAST. && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 11/14 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AMARILLO TX 950 PM CDT WED JUN 25 2008 .UPDATE... CONVECTION DISSIPATING ACROSS THE REGION. APPEARS THE THREAT FOR STORMS IS DIMINISHING FOR THE PANHANDLES. RUC AND NAM DO SUGGEST THAT AN ISOLATED STORM MAY STILL DEVELOP OVERNIGHT. SO LOWERED POPS TO SLIGHT CHANCE THROUGH 12Z. JJB && .PREV DISCUSSION... /ISSUED 621 PM CDT WED JUN 25 2008/ AVIATION... CONVECTION EXPECTED TO AFFECT MAILY THE GUYMON AND DALHART TAF SITES THIS EVENING...AND MAY POSSIBLY AFFECT THE AMARILLO TAF SITE LATER THIS EVENING IF THEY CONTINUE TO HOLD TOGETHER AFTER SUNSET. OTHERWISE...SOUTH TO SOUTHWEST WINDS AROUND 10 TO 15 KNOTS TONIGHT WILL INCREASE THURSDAY MORNING TO 15 TO 25 KNOTS THROUGH THURSDAY AFTERNOON. VFR CONDITIONS WILL PERSIST WITH ONLY FEW TO SCATTERED CUMULUS AND SCATTERED TO BROKEN HIGH CLOUDS EXPECTED. SCHNEIDER PREV DISCUSSION... /ISSUED 224 PM CDT WED JUN 25 2008/ DISCUSSION... THUNDERSTORMS HAVE DEVELOPED EARLY THIS AFTERNOON ACROSS THE MOUNTAINS OF NEW NEW MEXICO...SOUTHERN COLORADO AND ALONG A SURFACE TROUGH THROUGH NORTHEAST NEW MEXICO. THESE STORMS SHOULD AGAIN MOVE SOUTHEAST LATE THIS AFTERNOON AND TONIGHT ACROSS MUCH OF THE PANHANDLES IN A NORTHWEST FLOW ALOFT. DO NOT SEE MUCH CHANGE IN THE PATTERN THROUGH THIS FORECAST. RIDGING WILL CONTINUE ACROSS THE SOUTHERN AND CENTRAL ROCKIES AND UPPER LEVEL TROUGHING WILL BE FOUND ACROSS THE EASTERN HALF OF THE U.S. A STRONG UPPER LEVEL LOW PRESSURE SYSTEM WILL DIVE SOUTHEAST INTO NORTHERN MINNESOTA BY FRIDAY WHICH WILL HELP TO DRIVE A COLD FRONT THROUGH THE PANHANDLES BY EARLY SATURDAY MORNING. THIS FRONT WILL BE ANOTHER FOCUS FOR THUNDERSTORM DEVELOPMENT BESIDES THE MOUNTAINS...SO CHANCES FOR STORMS MAY BE A LITTLE ENHANCED. THE NORTHWEST FLOW ACROSS THE PANHANDLES WILL INCREASE SOME AS THE UPPER LEVEL TROUGH GETS CARVED OUT OVER THE EASTERN HALF OF THE U.S. AND THE RIDGE STAYS PUT OVER THE ROCKIES. THIS WILL KEEP THE THREAT OF AFTERNOON AND NIGHTTIME THUNDERSTORMS GOING ACROSS THE PANHANDLES INTO MID NEXT WEEK. LOW LEVEL MOISTURE AND THE INSTABILITY WILL NOT BE GOING ANYWHERE THROUGH THIS FORECAST...SO SEVERE THUNDERSTORMS AND LOCALLY HEAVY RAINFALL WILL CONTINUE TO BE THREATS. FIRE WEATHER... LIGHTNING WILL BE A THREAT FOR STARTING WILDFIRES. BUT...WITH THE MOISTURE IN PLACE AND LIGHTER WINDS THE OVERALL WILDFIRE DANGER WILL BE LOW THROUGH THIS FORECAST. && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 11/14 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 114 PM CDT TUE JUN 24 2008 .UPDATE...DID A QUICK UPDATE TO INCERASE POPS SOUTHERN AREAS AND NUDGE TEMPERATURES UP SOME. ZFP AND GRIDDED PRODUCTS OUT. && .PREV DISCUSSION... /ISSUED 1244 PM CDT TUE JUN 24 2008/ AVIATION... CONVECTION DEVELOPING AND WILL BEGIN TO MOVE FARTHER INLAND DURING THE AFTERNOON. HAVE INCLUDED VCTS IN THE KALI AND KVCT TAFS FOR THIS AFTN WITH TEMPOS (19Z-21Z KALI AND 20Z-24Z KVCT) WITH WIND GUSTS 30 KTS IN THUNDER (BASED ON SOUNDING AND OBS WITH THUNDER IN SOUTH TEXAS). VFR CONDITIONS OUTSIDE OF THUNDER AND GENERALLY EXPECTED OVERNIGHT AND THRU 18Z. POSSIBLE SHOWERS KALI AND KCRP AFTER 12Z (VCSH FOR NOW)...WTIH THUNDER POSSIBLE KVCT (PROB30) WHERE MOISTURE...FORCING AND SURFACE CONVERGENCE BEST. EXPECT MORE WIND THAN HAVE SEEN RECENTLY AS GRADIENT TIGHTENS A BIT MORE AND BOUNDARY LAYER WINDS INCREASE. HIER BOUNDARY LAYER WINDS SHOULD PRECLUDE ANY MVFR BR. PREV DISCUSSION... /ISSUED 936 AM CDT TUE JUN 24 2008/ UPDATE...MADE A FEW CHANGES TO THE PREVIOUS PACKAGE. INITAL CONVECTION OVER THE NORTHEAST WATERS AND INLAND AREAS EARLY THIS MORNING HAS MOVED INTO THE KHGX CWFA...BUT RADAR IS SHOWING ANOTHER AREA OF CONVECTION IN THE KBRO WATERS MOVING NORTH. ALTHOUGH SOME OF THIS MAY BEGIN TO WEAKEN AS IT MOVES INTO THE CWFA DUE TO THE SEA BREEZE BEGINNING...DO EXPECT SOME TO GET INTO THE AREA AND ALSO THIS IS INDICATIVE OF INCREASE IN MOISTURE AND STRONGER THETA-E ADVECTION. ALTHOUGH SEABREEZE TIMING ISSUES WILL COME INTO PLAY...HAVE DECIDED TO INCREASE POPS A BIT OVER THE AREA DUE TO THE MOISTURE INCREASE AND CONVERGE/LACK OF CAP LATER TODAY (RUC MODEL SHOWING REASONABLE AFTERNOON CONVERGENCE). STILL...WILL MAINTAIN SLIGHT CHANCE POPS EXCEPT OVER THE NORTHEAST WHERE MOISTURE ADVECTION IS BEST AND WHERE ACTIVITY IS HEADING SO CHANCE POPS THERE. MADE SOME ADJUSTMENTS TO CLOUDS AND MOISTURE GRIDS AS WELL...BUT OVERALL DID NOT MAKE TOO MANY CHANGES AFTER THE FIRST PERIOD. INLAND PRODUCTS OUT...CWFCRP WILL BE ISSUED BEFORE 10 AM. PREV DISCUSSION... /ISSUED 423 AM CDT TUE JUN 24 2008/ SHORT-TERM (TODAY THROUGH WEDNESDAY)...THE COMBINATION OF A WEAKNESS IN THE UPPER HEIGHT PATTERN AND INCREASED MSTR (BASED ON GOES SOUNDER PW INCREASES OVR THE SWRN GULF/GFS PROG OF INCREASING PW VALUES FROM SE TO NW ACRS THE WRN GULF/ERN CWFA) AND INSTABILITY WILL RESULT IN AN INCREASING CHANCE FOR CONVECTION DRG THE PERIOD. FCSTG A LESS THAN 20% CHANCE OF PCPN THIS AFTN AND A 30% CHANCE FOR ACTIVITY OVR THE NERN CWFA FOR WED AFTN. EXPECT MAXIMUM HEAT INDEX VALUES TO REMAIN BELOW 105F TDA/WED. AVIATION...PATCHY MVFR CONDITIONS EARLY THIS MORNING OVR PORTIONS OF THE COASTAL BEND/VICTORIA CROSSROADS...YET PREDOMINATE VFR CONDITIONS EXPECTED THIS AFTN. MVFR CONDITIONS EXPECTED AREAWIDE WED MORNING. MVFR CEILINGS/VSBYS EXPECTED NEAR CONVECTION. MARINE...GENERALLY WEAK TO MODERATE ONSHORE FLOW EXPECTED DRG THE PERIOD...RESULTING IN WIND/SEAS BELOW SCEC. FIRE WEATHER...MINIMUM RELATIVE HUMIDITY VALUES BELOW 30% EXPECTED OVR THE WRN CWFA THIS AFTN...YET WIND WL REMAIN BELOW RED FLAG CONDITIONS. LONG-TERM (WEDNESDAY NIGHT THROUGH MONDAY)...LITTLE TO NO CHANGE IN THE LARGE SCALE PATTERN THROUGH MUCH OF THE PERIOD...WHICH SHOWS A DEEP LAYER RIDGE AXIS RUNNING GENERALLY E/W...FROM THE DESERT SW...EASTWARD ACROSS THE N GULF. MODELS SEEM TO BE INDICATING A LITTLE MORE MOISTURE EARLIER IN THE PERIOD (THURSDAY)...BUT HAVE MAINTAINED SLT CHC POPS FOR NOW UNTIL A BETTER TREND BECOMES ESTABLISHED. MORE SIGNIFICANT CHANCES FOR RAINFALL STILL SEEM TO BE LATE IN THE PERIOD ASSOCIATED WITH AN EASTERLY WAVE. THE EUROPEAN AND GFS CONTINUE TO SHOW THIS WAVE...WITH ENHANCED MOISTURE... REACHING THE W GULF AND S TX BY SUNDAY. HAVE NUDGED UP POPS ANOTHER 10% FOR SUNDAY AND MONDAY...BUT THERE IS STILL CONSIDERABLE UNCERTAINTY GIVEN THAT IT IS DAY 6 AND 7. LOW LEVEL FLOW WILL CONTINUE TO BE SE FOR MOST OF THE PERIOD...WITH CONVECTION FOCUSING MAINLY WITH THE SEA BREEZE...THEN PUSHING INLAND EACH AFTERNOON. PRECIP TIMING COULD BE MORE SPREAD OUT BY SUNDAY AND MONDAY IF THE EASTERLY WAVE REACHES THE AREA. WINDS WILL BE STRONGEST EACH AFTERNOON AND EVENING AS THE GULF BREEZE COMBINES WITH THE SYNOPTIC SE FLOW TO PRODUCE 15+KT WINDS NEAR THE COAST. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 93 77 90 74 93 / 30 20 20 20 20 VICTORIA 95 73 91 73 94 / 30 20 30 20 20 LAREDO 103 78 100 79 102 / 10 10 10 10 10 ALICE 97 73 93 74 96 / 30 20 20 20 20 ROCKPORT 91 80 88 79 88 / 30 20 20 20 20 COTULLA 100 73 96 75 99 / 10 10 10 10 10 KINGSVILLE 95 75 92 77 95 / 30 20 20 20 20 NAVY CORPUS 89 80 87 79 89 / 30 20 20 20 20 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ GW/86...SHORT TERM TE/81...LONG TERM tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 1244 PM CDT TUE JUN 24 2008 .AVIATION... CONVECTION DEVELOPING AND WILL BEGIN TO MOVE FARTHER INLAND DURING THE AFTERNOON. HAVE INCLUDED VCTS IN THE KALI AND KVCT TAFS FOR THIS AFTN WITH TEMPOS (19Z-21Z KALI AND 20Z-24Z KVCT) WITH WIND GUSTS 30 KTS IN THUNDER (BASED ON SOUNDING AND OBS WITH THUNDER IN SOUTH TEXAS). VFR CONDITIONS OUTSIDE OF THUNDER AND GENERALLY EXPECTED OVERNIGHT AND THRU 18Z. POSSIBLE SHOWERS KALI AND KCRP AFTER 12Z (VCSH FOR NOW)...WTIH THUNDER POSSIBLE KVCT (PROB30) WHERE MOISTURE...FORCING AND SURFACE CONVERGENCE BEST. EXPECT MORE WIND THAN HAVE SEEN RECENTLY AS GRADIENT TIGHTENS A BIT MORE AND BOUNDARY LAYER WINDS INCREASE. HIER BOUNDARY LAYER WINDS SHOULD PRECLUDE ANY MVFR BR. && .PREV DISCUSSION... /ISSUED 936 AM CDT TUE JUN 24 2008/ UPDATE...MADE A FEW CHANGES TO THE PREVIOUS PACKAGE. INITAL CONVECTION OVER THE NORTHEAST WATERS AND INLAND AREAS EARLY THIS MORNING HAS MOVED INTO THE KHGX CWFA...BUT RADAR IS SHOWING ANOTHER AREA OF CONVECTION IN THE KBRO WATERS MOVING NORTH. ALTHOUGH SOME OF THIS MAY BEGIN TO WEAKEN AS IT MOVES INTO THE CWFA DUE TO THE SEA BREEZE BEGINNING...DO EXPECT SOME TO GET INTO THE AREA AND ALSO THIS IS INDICATIVE OF INCREASE IN MOISTURE AND STRONGER THETA-E ADVECTION. ALTHOUGH SEABREEZE TIMING ISSUES WILL COME INTO PLAY...HAVE DECIDED TO INCREASE POPS A BIT OVER THE AREA DUE TO THE MOISTURE INCREASE AND CONVERGE/LACK OF CAP LATER TODAY (RUC MODEL SHOWING REASONABLE AFTERNOON CONVERGENCE). STILL...WILL MAINTAIN SLIGHT CHANCE POPS EXCEPT OVER THE NORTHEAST WHERE MOISTURE ADVECTION IS BEST AND WHERE ACTIVITY IS HEADING SO CHANCE POPS THERE. MADE SOME ADJUSTMENTS TO CLOUDS AND MOISTURE GRIDS AS WELL...BUT OVERALL DID NOT MAKE TOO MANY CHANGES AFTER THE FIRST PERIOD. INLAND PRODUCTS OUT...CWFCRP WILL BE ISSUED BEFORE 10 AM. PREV DISCUSSION... /ISSUED 423 AM CDT TUE JUN 24 2008/ SHORT-TERM (TODAY THROUGH WEDNESDAY)...THE COMBINATION OF A WEAKNESS IN THE UPPER HEIGHT PATTERN AND INCREASED MSTR (BASED ON GOES SOUNDER PW INCREASES OVR THE SWRN GULF/GFS PROG OF INCREASING PW VALUES FROM SE TO NW ACRS THE WRN GULF/ERN CWFA) AND INSTABILITY WILL RESULT IN AN INCREASING CHANCE FOR CONVECTION DRG THE PERIOD. FCSTG A LESS THAN 20% CHANCE OF PCPN THIS AFTN AND A 30% CHANCE FOR ACTIVITY OVR THE NERN CWFA FOR WED AFTN. EXPECT MAXIMUM HEAT INDEX VALUES TO REMAIN BELOW 105F TDA/WED. AVIATION...PATCHY MVFR CONDITIONS EARLY THIS MORNING OVR PORTIONS OF THE COASTAL BEND/VICTORIA CROSSROADS...YET PREDOMINATE VFR CONDITIONS EXPECTED THIS AFTN. MVFR CONDITIONS EXPECTED AREAWIDE WED MORNING. MVFR CEILINGS/VSBYS EXPECTED NEAR CONVECTION. MARINE...GENERALLY WEAK TO MODERATE ONSHORE FLOW EXPECTED DRG THE PERIOD...RESULTING IN WIND/SEAS BELOW SCEC. FIRE WEATHER...MINIMUM RELATIVE HUMIDITY VALUES BELOW 30% EXPECTED OVR THE WRN CWFA THIS AFTN...YET WIND WL REMAIN BELOW RED FLAG CONDITIONS. LONG-TERM (WEDNESDAY NIGHT THROUGH MONDAY)...LITTLE TO NO CHANGE IN THE LARGE SCALE PATTERN THROUGH MUCH OF THE PERIOD...WHICH SHOWS A DEEP LAYER RIDGE AXIS RUNNING GENERALLY E/W...FROM THE DESERT SW...EASTWARD ACROSS THE N GULF. MODELS SEEM TO BE INDICATING A LITTLE MORE MOISTURE EARLIER IN THE PERIOD (THURSDAY)...BUT HAVE MAINTAINED SLT CHC POPS FOR NOW UNTIL A BETTER TREND BECOMES ESTABLISHED. MORE SIGNIFICANT CHANCES FOR RAINFALL STILL SEEM TO BE LATE IN THE PERIOD ASSOCIATED WITH AN EASTERLY WAVE. THE EUROPEAN AND GFS CONTINUE TO SHOW THIS WAVE...WITH ENHANCED MOISTURE... REACHING THE W GULF AND S TX BY SUNDAY. HAVE NUDGED UP POPS ANOTHER 10% FOR SUNDAY AND MONDAY...BUT THERE IS STILL CONSIDERABLE UNCERTAINTY GIVEN THAT IT IS DAY 6 AND 7. LOW LEVEL FLOW WILL CONTINUE TO BE SE FOR MOST OF THE PERIOD...WITH CONVECTION FOCUSING MAINLY WITH THE SEA BREEZE...THEN PUSHING INLAND EACH AFTERNOON. PRECIP TIMING COULD BE MORE SPREAD OUT BY SUNDAY AND MONDAY IF THE EASTERLY WAVE REACHES THE AREA. WINDS WILL BE STRONGEST EACH AFTERNOON AND EVENING AS THE GULF BREEZE COMBINES WITH THE SYNOPTIC SE FLOW TO PRODUCE 15+KT WINDS NEAR THE COAST. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 93 77 90 74 93 / 20 20 20 20 20 VICTORIA 94 73 91 73 94 / 30 20 30 20 20 LAREDO 103 78 100 79 102 / 10 10 10 10 10 ALICE 97 73 93 74 96 / 20 20 20 20 20 ROCKPORT 91 80 88 79 88 / 30 20 20 20 20 COTULLA 100 73 96 75 99 / 10 10 10 10 10 KINGSVILLE 95 75 92 77 95 / 20 20 20 20 20 NAVY CORPUS 89 80 87 79 89 / 20 20 20 20 20 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ GW/86...SHORT TERM TE/81...LONG TERM tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 936 AM CDT TUE JUN 24 2008 .UPDATE...MADE A FEW CHANGES TO THE PREVIOUS PACKAGE. INITAL CONVECTION OVER THE NORTHEAST WATERS AND INLAND AREAS EARLY THIS MORNING HAS MOVED INTO THE KHGX CWFA...BUT RADAR IS SHOWING ANOTHER AREA OF CONVECTION IN THE KBRO WATERS MOVING NORTH. ALTHOUGH SOME OF THIS MAY BEGIN TO WEAKEN AS IT MOVES INTO THE CWFA DUE TO THE SEA BREEZE BEGINNING...DO EXPECT SOME TO GET INTO THE AREA AND ALSO THIS IS INDICATIVE OF INCREASE IN MOISTURE AND STRONGER THETA-E ADVECTION. ALTHOUGH SEABREEZE TIMING ISSUES WILL COME INTO PLAY...HAVE DECIDED TO INCREASE POPS A BIT OVER THE AREA DUE TO THE MOISTURE INCREASE AND CONVERGE/LACK OF CAP LATER TODAY (RUC MODEL SHOWING REASONABLE AFTERNOON CONVERGENCE). STILL...WILL MAINTAIN SLIGHT CHANCE POPS EXCEPT OVER THE NORTHEAST WHERE MOISTURE ADVECTION IS BEST AND WHERE ACTIVITY IS HEADING SO CHANCE POPS THERE. MADE SOME ADJUSTMENTS TO CLOUDS AND MOISTURE GRIDS AS WELL...BUT OVERALL DID NOT MAKE TOO MANY CHANGES AFTER THE FIRST PERIOD. INLAND PRODUCTS OUT...CWFCRP WILL BE ISSUED BEFORE 10 AM. && .PREV DISCUSSION... /ISSUED 423 AM CDT TUE JUN 24 2008/ SHORT-TERM (TODAY THROUGH WEDNESDAY)...THE COMBINATION OF A WEAKNESS IN THE UPPER HEIGHT PATTERN AND INCREASED MSTR (BASED ON GOES SOUNDER PW INCREASES OVR THE SWRN GULF/GFS PROG OF INCREASING PW VALUES FROM SE TO NW ACRS THE WRN GULF/ERN CWFA) AND INSTABILITY WILL RESULT IN AN INCREASING CHANCE FOR CONVECTION DRG THE PERIOD. FCSTG A LESS THAN 20% CHANCE OF PCPN THIS AFTN AND A 30% CHANCE FOR ACTIVITY OVR THE NERN CWFA FOR WED AFTN. EXPECT MAXIMUM HEAT INDEX VALUES TO REMAIN BELOW 105F TDA/WED. AVIATION...PATCHY MVFR CONDITIONS EARLY THIS MORNING OVR PORTIONS OF THE COASTAL BEND/VICTORIA CROSSROADS...YET PREDOMINATE VFR CONDITIONS EXPECTED THIS AFTN. MVFR CONDITIONS EXPECTED AREAWIDE WED MORNING. MVFR CEILINGS/VSBYS EXPECTED NEAR CONVECTION. MARINE...GENERALLY WEAK TO MODERATE ONSHORE FLOW EXPECTED DRG THE PERIOD...RESULTING IN WIND/SEAS BELOW SCEC. FIRE WEATHER...MINIMUM RELATIVE HUMIDITY VALUES BELOW 30% EXPECTED OVR THE WRN CWFA THIS AFTN...YET WIND WL REMAIN BELOW RED FLAG CONDITIONS. LONG-TERM (WEDNESDAY NIGHT THROUGH MONDAY)...LITTLE TO NO CHANGE IN THE LARGE SCALE PATTERN THROUGH MUCH OF THE PERIOD...WHICH SHOWS A DEEP LAYER RIDGE AXIS RUNNING GENERALLY E/W...FROM THE DESERT SW...EASTWARD ACROSS THE N GULF. MODELS SEEM TO BE INDICATING A LITTLE MORE MOISTURE EARLIER IN THE PERIOD (THURSDAY)...BUT HAVE MAINTAINED SLT CHC POPS FOR NOW UNTIL A BETTER TREND BECOMES ESTABLISHED. MORE SIGNIFICANT CHANCES FOR RAINFALL STILL SEEM TO BE LATE IN THE PERIOD ASSOCIATED WITH AN EASTERLY WAVE. THE EUROPEAN AND GFS CONTINUE TO SHOW THIS WAVE...WITH ENHANCED MOISTURE... REACHING THE W GULF AND S TX BY SUNDAY. HAVE NUDGED UP POPS ANOTHER 10% FOR SUNDAY AND MONDAY...BUT THERE IS STILL CONSIDERABLE UNCERTAINTY GIVEN THAT IT IS DAY 6 AND 7. LOW LEVEL FLOW WILL CONTINUE TO BE SE FOR MOST OF THE PERIOD...WITH CONVECTION FOCUSING MAINLY WITH THE SEA BREEZE...THEN PUSHING INLAND EACH AFTERNOON. PRECIP TIMING COULD BE MORE SPREAD OUT BY SUNDAY AND MONDAY IF THE EASTERLY WAVE REACHES THE AREA. WINDS WILL BE STRONGEST EACH AFTERNOON AND EVENING AS THE GULF BREEZE COMBINES WITH THE SYNOPTIC SE FLOW TO PRODUCE 15+KT WINDS NEAR THE COAST. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 93 77 90 74 93 / 20 20 20 20 20 VICTORIA 94 73 91 73 94 / 30 20 30 20 20 LAREDO 103 78 100 79 102 / 10 10 10 10 10 ALICE 97 73 93 74 96 / 20 20 20 20 20 ROCKPORT 91 80 88 79 88 / 30 20 20 20 20 COTULLA 100 73 96 75 99 / 10 10 10 10 10 KINGSVILLE 95 75 92 77 95 / 20 20 20 20 20 NAVY CORPUS 89 80 87 79 89 / 20 20 20 20 20 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ GW/86...SHORT TERM TE/81...LONG TERM tx AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE LA CROSSE WI 745 PM CDT WED JUN 25 2008 .UPDATE... QUITE AN AIRMASS DIFFERENCE BETWEEN SEVERAL DIFFERENT WEAK FRONTAL ZONES ACROSS THE AREA THIS EVENING. WEAK NE/SW ORIENTED COLD FRONT /A REFLECTION OF DEPARTING ONTARIO CANADA HEIGHT FALLS/ IS SHIFTING STEADILY INTO THE FORECAST AREA. 26.00Z KMPX RAOB WAS A JAW-DROPPER IN THE MAIN SUBSIDENCE REGION BEHIND THE FRONT...WITH PWATS CUT IN HALF /1.2 TO 0.6 INCH/ AND RATHER DEEP NWLY FLOW. CONTRAST THIS...TO AIRMASS SOUTH OF WEAK/DIFFUSE WARM FRONTAL STRUCTURE FROM WHERE IT INTERSECTS COLD FRONT IN NWRN IA...DOWN ALONG I-80 TOWARD MUSCATINE IOWA....WHERE DEWPOINTS IN THE UPPER 70S AND SBCAPES TOWARD 5000 J/KG ARE COMMON. NO SURPRISE...WITH THE ADDITION OF SUBTLE MID LEVEL CIRCULATION /MCV/ HITTING THE INSTABILITY GRADIENT IN PLACE FROM SRN IA INTO NRN IA THAT EXPLOSIVE DEEP CONVECTION HAS OCCURRED...ESPECIALLY ALONG WARM FRONTAL STRUCTURE OVER CNTL IA...WHERE GOLFBALL HAIL HAS BEEN OBSERVED. SHORT RANGE LOCAL WRF-BASED 13KM RUC MODEL...AGREES WHOLEHEARTEDLY WITH 26.15Z SREF PROBS THAT THIS COMPLEX OF SCT STORMS IN CNTL IA WILL SINK SLOWLY SOUTHEAST AS IT MATURES THIS EVENING. EARLIER E-W BAND OF CONVECTION HANCOCK/CERRO GORDO COUNTY HAS FORMED A COLD POOL IS NOW PROPAGATING SOUTH/EAST WITH MCV TAKING MAIN ECHOES JUST SOUTHWEST OF CCY/OLZ AREAS. MAY GET QUITE MESSY IN CNTL IA TONIGHT GIVEN MERGING MCS CLUSTERS AND HEAVY RAIN. GIVEN TRENDS IN 26.18Z WRF/GFS OF SIGNIFICANT DRYING IN THE SOUNDINGS NORTH OF I-90...EXPECT MUCH OF RAIN CHANCES REST OF NIGHT TO BE CONFINED TO THE FAR SOUTH. COULD STILL POP A SHOWER IN THE FAR NORTH WITH COLD FRONT...BUT CUMULUS FIELD IS LOSING ORGANIZATION. UPDATED FORECAST/HAZ WEATHER OUTLOOK IS OUT. BINAU && .PREV DISCUSSION... /ISSUED 325 PM CDT WED JUN 25 2008/ SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT FORECAST CONCERNS THIS PACKAGE CONTINUE TO BE CONVECTION POTENTIAL AND RAIN AMOUNTS. DATA ANALYSIS THIS AFTERNOON HAD AN AREA OF LOW PRESSURE OVER NORTHERN MN WITH A TROUGH EXTENDING SOUTH/SOUTHWEST THROUGH WESTERN IA INTO EASTERN NE. MEANWHILE...WATER VAPOR/VIS SATELLITE IMAGERY SHOWED A REMNANT MVC MEANDERING EASTWARD ACROSS NORTHWEST IA. A FEW LIGHT SHRA SHOWING UP ON THE RADAR MOSAIC ASSOCIATED WITH THIS FEATURE...BUT NO GROUND REPORTS THUS FAR. VIS SATELLITE ALSO SHOWING SCATTERED CU FIELD IN WEAK SURFACE/MOISTURE CONVERGENCE AHEAD OF THE TROUGH ACROSS MN. TEMPERATURES MORE INDICATIVE OF SUMMER THIS AFTERNOON WITH READINGS IN THE UPPER 70S TO MID 80S WITH DEW POINTS IN THE 60S. CURRENTLY SPC MESOANALYSIS TOOL SHOWING 100MB ML CAPE IN THE 500-1500J/KG RANGE ACROSS THE AREA WITH ALMOST NIL CIN. 25.12Z GFS/NAM STILL IN FAIRLY GOOD AGREEMENT THOUGH THE PERIOD WITH SPEED AND INTENSITY OF SYNOPTIC SCALE FEATURES AFFECTING THE AREA THROUGH THE PERIOD. DIFFERENCES ARISE IN PLACEMENT AND AMOUNT OF RAINFALL. CONTINUED TO TAKE A BLEND APPROACH AS FAR AS FINAL QPF PLACEMENT/AMOUNT WAS CONCERNED. GFS/NAM/SREF ALL HINTING AT SOME CONVECTION ALONG THE TROUGH AS IT MOVES FROM MN THROUGH WI THIS EVENING. WATER VAPOR IMAGERY WAS INDICATING SOME DECENT SUBSIDENCE/DRYING BEHIND THIS TROUGH AS IT SLIDES SOUTHEAST THROUGH THE AREA THIS EVENING. SO EXPECT PRECIPITATION CHANCES TO BE CONFINED ACROSS THE FAR SOUTH WHERE TROUGH WILL LAY UP AFTER MIDNIGHT. MODELS IN GOOD AGREEMENT THAT BULK OF 925-850MB MOISTURE TRANSPORT TONIGHT WILL BE SOUTH OF I-80...SO RESULTANT BULK OF SHRA/TS SHOULD REMAIN SOUTH OF THE AREA. BOTTOM LINE...MAINTAINED SMALL CHANCES OF SHRA/TS ACROSS THE NORTH THIS EVENING...THEN CONFINED SHRA/TS CHANCES TO FAR SOUTH WHERE THE TROUGH WILL LAY UP COMBINED WITH NORTHERN PERIPHERY OF MOISTURE TRANSPORT. NOT TOO CONCERNED WITH SEVERE POTENTIAL. BEST OPPORTUNITY WOULD BE ACROSS THE NORTH THIS EVENING WHERE SLIGHTLY BETTER BULK SHEAR AND CAPE IN THE 1000-1500J/KG WILL EXIST. AFTER MIDNIGHT ACROSS THE SOUTH...ML CAPE DIMINISHES INTO THE 500-1000J/KG RANGE...PRETTY MINIMAL FOR SEVERE THREAT. FOR THURSDAY...THE TROUGH STARTS TO LIFT NORTHWARD BACK INTO THE AREA AS SURFACE CYCLOGENESIS TAKES PLACE OVER THE HIGH PLAINS. BETTER 925-850MB TRANSPORT ADVECTS INTO/OVER THE FRONTAL BOUNDARY DURING THE AFTERNOON HOURS FOR INCREASING SHRA/TS CHANCES. BETTER CHANCES WILL EXIST ACROSS THE SOUTHWEST WITH DIMINISHING CHANCES TO THE NORTHEAST. NAM INDICATING ML CAPE IN THE 1500-2000J/KG RANGE ALONG THE FRONTAL BOUNDARY. HOWEVER...FAVORABLE BULK SHEAR REMAINS WEST OF THE AREA. SO...EXPECT SCATTERED SHRA/TS ALONG THE FRONTAL BOUNDARY WITH MOISTURE CONVERGENCE...BUT SEVERE THREAT SEEMS MITIGATED BY LACK OF GOOD SHEAR. CANNOT HOWEVER RULE OUT SOME SEVERE HAIL WITH STRONGER UPDRAFTS DURING THE AFTERNOON. FOR THURSDAY NIGHT THROUGH FRIDAY MORNING...LOW PRESSURE MOVING OUT OF THE PLAINS WILL LIFT THE WARM FRONT THROUGH THE AREA. MODELS INDICATING MODERATE AMOUNT OF MOISTURE TRANSPORT INTO THE FRONT AS IT MOVES THROUGH THE AREA WITH 0-3KM MUCAPE INCREASING INTO THE 2500-3000J/KG RANGE AND 0-3KM BULK SHEAR INCREASING INTO THE 25 TO 35KT RANGE. SO...EXPECTING A GOOD CHANCE TO LIKELIHOOD OF SHRA/TS ACTIVITY WITH PERHAPS A FEW SEVERE THUNDERSTORMS CONTAINING LARGE HAIL/DAMAGING WINDS THURSDAY NIGHT/FRIDAY MORNING. IN ADDITION...WITH PRECIPITABLE WATER VALUES HOVERING IN THE 1.5 TO 2.0 INCH RANGE...HEAVY POCKETS OF RAINFALL IS ALSO LIKELY. HEAVY RAINFALL THREAT IS DETAILED IN THE HYDROLOGY SECTION BELOW. THE LOW CONTINUES TO DEEPEN AND MOVE ALONG THE CANADA/MN BORDER FRIDAY AFTERNOON. THIS PUSHES A COLD FRONT INTO THE AREA. THE QUESTION BECOMES ON HOW FAST THE ATMOSPHERE CAN RECOVER FROM THURSDAY NIGHT/FRIDAY MORNING CONVECTION. BOTH NAM AND GFS INDICATING COLD FRONT WILL BE ON TOP OF US BY NOON WITH MUCAPE VALUES INCREASING INTO THE 2500-4500J/KG RANGE. BULK SHEAR ALSO APPEARS SUFFICIENT FOR SEVERE THUNDERSTORM PRODUCTION. HELICITY IN THE LOWEST 3KM ALSO POINTS TOWARD THE POSSIBILITY OF A TORNADO OR TWO. THE FRONT AND BULK OF SHRA TS ACTIVITY APPEARS LIKE IT WILL MOVE EAST/SOUTHEAST OF THE AREA BY FRIDAY EVENING. FOR SATURDAY THROUGH SATURDAY NIGHT...THE LOW WILL BECOME VERTICALLY STACKED OVER SOUTHWEST ONTARIO WITH COLD POOL CIRCULATING OVERHEAD. THIS PRODUCES STEEP LAPSE RATES AND SHRA/TS CHANCES ACROSS THE AREA THROUGH THIS PERIOD. LONG TERM...SUNDAY THROUGH WEDNESDAY 25.00Z ECMWF/25.06Z GFS REMAIN IN GOOD AGREEMENT THROUGH MONDAY WITH UPPER LOW SLOWLY SHIFTING EAST OF THE AREA AS A RIDGE BUILD IN FROM THE PLAINS. CONTINUED SHRA/ISOLD T CHANCES THROUGH SUNDAY NIGHT AS THE AREA REMAINS IN WESTERN PERIPHERY OF COLD POOL ALOFT. TEMPERATURES WILL REMAIN COOLER THAN NORMAL WITH SCATTERED PRECIPITATION AND MIXING OF 5-6C AIR FROM 850MB. WITH HEIGHTS BUILDING ON MONDAY AND SUBSIDENCE...IT SHOULD BE DRY WITH HIGHS REBOUNDING BACK TO NEAR SEASONAL NORMALS IN THE UPPER 70S TO LOWER/MIDDLE 80S. TEMPERATURES WILL CONTINUE TO WARM A COUPLE MORE DEGREES TUESDAY AS THE RIDGE BUILDS OVER THE AREA. BY WEDNESDAY...BOTH THE GFS/ECMWF HINT AT A MID-LEVEL SHORTWAVE TROUGH/SURFACE COLD FRONT WILL ROUND THE TOP OF THE RIDGE AND AFFECT THE AREA TUESDAY NIGHT THROUGH WEDNESDAY WITH A CHANCE OF SHRA/TS. AVIATION... A WEAK COLD FRONT OVER CENTRAL MINNESOTA WILL MOVE EAST ACROSS BOTH THE RST AND LSE TAF SITES LATE THIS AFTERNOON AND EVENING. A WEAK MESOSCALE VORTEX OVER NORTHEAST NEBRASKA AND SOUTHEAST SOUTH DAKOTA WILL MOVE ALONG THE COLD FRONT AND INTO NORTHERN IOWA THIS EVENING AND TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG THE FRONT AND ASSOCIATED MESOSCALE VORTEX THIS AFTERNOON. DUE TO CONCERNS WITH TIMING OF THE FRONT AND SCATTER IN NATURE OF CONVECTION HAVE KEPT VCSH AT BOTH RST AND LSE AFTER 22-23Z. BOTH THE LATEST 25.12Z NAM AND GFS INDICATE SURFACE COLD FRONT TO MOVE INTO NORTHERN IOWA AFTER 06Z THURSDAY. WITH THE BEST FORCING AND MOISTURE CONVERGENCE WELL SOUTH OF TAF SITES...HAVE INTRODUCE DRY CONDITIONS AND SCATTERED CLOUDS AFTER 09Z. HYDROLOGY... WILL CONTINUE TO KEEP AN EYE OUT FOR FLOODING POTENTIAL MAINLY FROM THURSDAY THROUGH FRIDAY WITH PRECIPITABLE WATER VALUES INCREASING INTO 1.5 TO 2 INCH RANGE AND BETTER THUNDERSTORM ENVIRONMENT TO FOCUS HEAVIER RAINS. A WARM FRONT MOVING SLOWLY NORTHWARD THROUGH THE AREA THURSDAY THROUGH FRIDAY WILL PROVIDE THIS ENVIRONMENT. HOWEVER...OVERALL MODEL CONSENSUS IS THAT 1 TO 2 INCHES OF RAINFALL WILL BE POSSIBLE FROM TONIGHT THROUGH FRIDAY...WITH THE BULK OF THIS FALLING IN THE THURSDAY TROUGH FRIDAY TIME FRAME. BELIEVE SOME FOCUSED 2 TO 3 INCH AMOUNTS ARE POSSIBLE...BUT EXACT AREA AND TIMING IS STILL HARD TO PINPOINT AT THIS TIME. RIGHT NO IT APPEARS AREAS ALONG AND SOUTH OF I-90 WILL BE MORE SUSCEPTIBLE FOR HEAVIER RAINFALL POTENTIAL. BULK OF THIS AREA HAS HAD SOME DRYING OVER THE PAST FEW DAYS WITH SOILS NOW CAPABLE OF ABSORBING 1 TO 2 INCHES BEFORE RUNOFF OCCURS INTO STREAMS AND CREEKS. HOWEVER...IF INTENSE ENOUGH...RAINFALL COULD PRODUCE RUNOFF PROBLEMS QUICKER IN STEEPER TERRAIN AREAS. AS A RESULT WILL RE-ISSUE AN ESF TO ADDRESS THE HEAVY RAIN THREAT AND POTENTIAL FOR RUNOFF PROBLEMS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ 01/01 wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 252 PM CDT WED JUN 25 2008 .SHORT TERM... MCV ACROSS LOWER MI SHIFTING AWAY FROM SRN WI/N IL. RUC ANALYSIS DOES SHOW WEAK VORT LOBE HOWEVER SUBSIDENCE FIELD LEFT BEHIND BY DEPARTING VORT SEEMS TO BE PUTTING THE KIBOSH ON VERTICAL DEVELOPMENT. WITH SURFACE FRONT APPROACHING LATER TONIGHT MAY BE ENUF INSTABILITY COMBINED WITH WEAKENING SUBSIDENCE TO ALLOW SOMETHING TO FIRE. ALSO WATCHING INTERESTING LOOKING CLOUD MASS ACRS NRN IA WORKING EWD. NAM IS DRY AND GFS IS WET...ESPECIALLY OVER THE SRN CWA...SO WILL TRIM GFS MOS POPS...MUCH LIKE LAST NIGHT. APPROACHING FRONT SHOULD STALL OVER FAR SOUTHERN WISCONSIN OR NORTHERN ILLINOIS THURSDAY MORNING. NAM SHOWS CAPES AROUND 1700 J/KG THURSDAY AFTERNOON. HOWEVER MID LEVELS RATHER DRY...AND LOW LEVEL MOISTURE IS SHALLOW. ALSO NO TRIGGER WITH WEAK LOW LEVEL FLOW. MODELS DON`T GENERATE ANY SIGNIFICANT PRECIPITATION THURSDAY. CRAS MODEL ALSO SHOWS NO DEEP CONVECTION UNTIL POSSIBLY LATE THURSDAY AFTERNOON OVER THE FAR SOUTH...CLOSE TO THE EXPECTED SURFACE BOUNDARY. 850 MB FLOW INCREASES ACROSS NORTHEAST IOWA...WITH SOME CONVERGENCE AS WARM FRONT PUSHES NORTH. THIS WOULD BRING A POTENTIAL OF A MCS. SOME HEAVY RAINFALL POSSIBLE GIVEN PRECIPITABLE WATER VALUES INCREASING TO AROUND 1.70 INCHES. BEST CHANCE FOR SEVERE WEATHER AND HEAVY RAINFALL APPEARS TO BE FRIDAY AFTERNOON AND EVENING...AS A STRONG SHORTWAVE APPROACHES FROM THE NORTHWEST. UPPER DIFLUENCE ALONG WITH MODERATE INSTABILITY AND INCREASING SEVERE PARAMETERS. EHI VALUES RISE TO 2.75 WITH BULK RICHARDSON NUMBERS AROUND 20. THUS SOME SUPER CELL POTENTIAL AHEAD OF THE APPROACHING COLD FRONT. THIS SCENARIO COULD PRODUCE SOME TORNADO THREAT PROVIDING THE CAP BREAKS DURING OR LATE AFTERNOON. .LONG TERM... ECMWF SHOWED A DEEP SHORTWAVE TROUGH WITH A CUTOFF LOW PUSHING THROUGH THE GREAT LAKES REGION SATURDAY AND SUNDAY. WITH THE COLD AIR IN THE UPPER LEVELS...THE RESULTANT AFTERNOON INSTABILITY SHOULD PRODUCE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. BOTH THE ECMWF AND GFS KEEPS THE UPPER TROUGH OVER THE EASTERN GREAT LAKES REGION MONDAY...CLOSE ENOUGH FOR A CHANCE OF AFTERNOON SHOWERS. UPPER LEVEL RIDGING BEHIND THE SHORTWAVE WITH NORTHWEST FLOW OVER THE UPPER MISSISSIPPI VALLEY SHOULD THEN BRING QUIET WEATHER TO THE AREA. THE ECMWF IS A BIT MORE PROGRESSIVE WITH A SHORTWAVE OVER THE WEST BY MID WEEK...BUT THIS WOULD BECOME AN ISSUE MORE FOR WEDNESDAY NIGHT AND THURSDAY. && .AVIATION... WILL GO MAINLY VFR THIS PERIOD. MVFR CU FIELD EXPECTED TO DISSIPATE. MAY SEE SOME HAZE/LIGHT FOG AS WELL NOW THAT WE HAVE SOME HIGHER DEWS OVERTAKING THE CWA. CONFIDENCE IN CONVECTION LOW AT THE MOMENT SO WILL OPT TO LEAVE OUT OF TAFS...HOWEVER APPCH FRONT LATER IN THE NIGHT MAY SERVE AS A FOCUS. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ SHORT/LONG TERM...06/HENTZ AVIATION/MARINE...10/COLLAR wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIAMI FL 455 AM EDT THU JUN 26 2008 .DISCUSSION... THE LATEST WATER VAPOR IMAGERY...RUC ANALYSIS AND THE RECENT GUIDANCE INDICATE AN UPPER LEVEL RIDGE OVER THE SOUTH FLORIDA PENINSULA. A PLUME OF UPPER LEVEL MOISTURE AND CLOUDINESS CONTINUES TO COME ACROSS THE YUCATAN PENINSULA AND ACROSS THE GULF AND OVER THE SOUTH FLORIDA PENINSULA...WITH A PERSISTENT UPPER LEVEL TROUGH WELL ESTABLISHED OVER THE WESTERN GULF. A TROPICAL WAVE SOUTH OF CUBA IS ALSO INTERACTING WITH THE SOUTHERN EXTENSION OF THE UPPER LEVEL TROUGH AND ALSO CONTRIBUTING TO CONSIDERABLE CLOUDINESS IN THE SOUTHEASTERN GULF. RECENT GUIDANCE INDICATES THAT THE MID LEVELS WILL BE DRY IN THE SHORT TERM...WITH THE AFOREMENTIONED UPPER LEVEL MOISTURE AND ASSOCIATED CIRRUS PERSISTING ACROSS THE REGION FOR AT LEAST THE NEXT SEVERAL DAYS. WITH HIGH PRESSURE DOMINATING THE SOUTH FLORIDA PENINSULA AND LACK OF DEEP LAYERED MOISTURE...ONLY EXPECTING SCATTERED SHOWERS AND THUNDERSTORMS TODAY...WITH THE EAST TO EAST SOUTHEAST LOW TO MID LEVEL WINDS FAVORING THE WESTERN INTERIOR SECTIONS AND THE NAPLES AREA THIS AFTERNOON. THIS TREND SHOULD CONTINUE THROUGH THE WEEKEND. LATEST GUIDANCE SUGGESTS THAT PWATS SHOULD BE AROUND 1.7 INCHES THROUGH THIS PERIOD...SO ISOLATED AREAS OF LOCALLY HEAVY RAINFALL ARE POSSIBLE EACH AFTERNOON THROUGH THE WEEKEND...BUT AGAIN FAVORING THE WESTERN INTERIOR AND MAINLY DURING THE AFTERNOON. && .MARINE... LATEST GUIDANCE INDICATES THAT EAST TO EAST SOUTHEAST FLOW WILL PERSIST OVER THE LOCAL WATERS THROUGH THE WEEKEND. IN GENERAL THE WINDS OVER THE LOCAL ATLANTIC WATERS EAST OF PALM BEACH COUNTY ARE EXPECTED TO BE IN THE 5 TO 10 KNOT RANGE...WITH 10 TO 15 KNOTS ELSEWHERE OVER THE ATLANTIC WATERS. THE OFF SHORE GULF WATERS WILL BE NEAR 10 KNOTS WITH PERIODS OF 10 TO 15 KNOTS POSSIBLE. && .FIRE WEATHER... NO FIRE WEATHER CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 90 77 90 77 / 30 20 20 10 FORT LAUDERDALE 89 79 90 80 / 30 20 20 10 MIAMI 90 79 91 78 / 20 20 20 10 NAPLES 91 74 93 75 / 40 20 30 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ LONG TERM...60/BD SHORT TERM/AVIATION...47/RHG fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 1249 AM CDT THU JUN 26 2008 .UPDATE... INCLUSION OF 06Z TAFS AND CANCELLATION OF SVR TSTM WATCH 606. && .PREV DISCUSSION... THE FORECAST TONIGHT IS QUITE COMPLEX AS THERE ARE SEVERAL FEATURES OVER/NEAR THE CWA. CURRENTLY WE ARE QUITE UNSTABLE WITH 4000 J/KG OF CAPE OVER THE SW THIRD OF IA BUT SHEAR IS QUITE WEAK...GENERALLY 20-25KTS OR LESS. OVER THE NORTHWEST...A FRONTAL BOUNDARY EXISTS FROM A LOW IN NE MN. THE FRONT EXTENDS INTO FAR NW IA THEN ALONG THE NEB/SDKTA BORDER. THERE IS WEAK CONVERGENCE ALONG THE SURFACE FRONT BUT SO FAR IT HAS NOT BEEN ABLE TO PRODUCE/SUSTAIN THUNDERSTORMS. ALOFT...THE FLOW IS WEAK AND THERE IS NOT A LOT OF SUPPORT. HOWEVER...RUC ANALYSIS DOES INDICATE A COUPLE OF WEAK VORT CENTERS...ONE OVER NW IA...PROBABLY AIDING IN THE SHOWERS UP THERE...AND ONE IN NORTHEAST KS MOVING INTO SW IA. CAPE VALUES IN THIS AREA ARE EVEN HIGHER THAN IN SW IA AND THERE ARE NO THUNDERSTORMS DEVELOPING YET. HAVING SAID ALL THIS...ANY ONE OF THESE FEATURES CAN TRIGGER STORMS TONIGHT AT ANY TIME. THE LACK OF DEVELOPMENT THUS FAR IS THE PERPLEXING PART. MID/UPPER LEVEL WIND FIELDS ARE BETTER OVER MN CLOSER TO THE LOW. I WOULD EXPECT DEVELOPMENT TO INITIATE THERE THEN TRAVEL DOWN THE FRONTAL BOUNDARY THIS EVENING. I BELIEVE THE NAM HAS A GOOD HANDLE ON THE SCENARIO DEVELOPING THE PRECIP FURTHER SOUTH...WHERE THE THE FRONT WILL EVENTUALLY SAG INTO THE HIGH CAPE AREA. LATER TONIGHT A LLJ DEVELOPS AND THIS WILL PROBABLY AID IN THE DEVELOPMENT OF AN MCS MOVING SLOWLY ACROSS THE STATE OVERNIGHT INTO THURSDAY. WITH THE HIGH LEVEL OF UNCERTAINTY OVER JUST WHERE INITIATION WILL BEGIN I HAVE PLACED CHANCE POPS OVER THE CWA FOR TONIGHT. THE HIGHEST POPS STILL REMAIN NORTH BUT WITH FAIRLY DEEP MOISTURE OVER THE SOUTH...ANY STORMS THAT DEVELOP DOWN THERE WILL ALSO PRODUCE VERY HEAVY RAINFALL. MOST ACTIVE PERIOD REMAINS WITHIN THE FIRST 60 HOURS OF THE FORECAST PERIOD. A FEW THUNDERSTORMS POSSIBLY ONGOING AT THE START OF THE PERIOD AT 12Z THURSDAY. THE BIGGER SHOW IS STILL EXPECTED TO BE A DEVELOPING MCS OVER WYOMING LATE THIS EVENING THEN ROLL THROUGH SOUTH DAKOTA OVERNIGHT BEFORE REACHING NORTHERN IOWA DURING THE DAY ON THURSDAY. SOME SFC HEATING IS LIKELY AHEAD OF THE SYSTEM AND THIS SHOULD ALLOW FOR AN INCREASINGLY UNSTABLE AIR MASS TO DEVELOP FOR THE STORMS TO FEED ON. SEVERE STORMS ALONG WITH AREAS OF HEAVY RAINFALL WILL BE POSSIBLE. ADDITIONAL STORMS EXPECTED THURSDAY NIGHT BEFORE THE PRIMARY FRONTAL BOUNDARY ARRIVES ON FRIDAY. GOOD INSTABILITY LIKELY AGAIN ON FRIDAY WITH MIX LAYER CAPES OF 2000 TO 2500 J/KG HOWEVER THE MAIN UPPER LEVEL FORCING WILL PASS TO THE NORTH. STILL ENOUGH SHEAR WILL REMAIN FOR SOME SEVERE MULTICELL STORMS AND ISOLATED SUPER CELLS. THE WEEKEND WILL BE DOMINATED BY A LARGE UPPER LEVEL LOW MOVING SLOWING THROUGH THE WESTERN GREAT LAKES REGION BRINGING CYCLONIC FLOW TO IOWA. HAVE COOLED HIGH TEMPERATURES AND ADDED LOW POPS TO THE NORTHEAST FOR EACH AFTERNOON AS IMPULSES ROTATE AROUND THE UPPER LOW. COOL TEMPERATURES THROUGH THE COLUMN WILL LEAD TO SOME INSTABILITY DURING THE AFTERNOONS. GRADUALLY WARMER NEXT WEEK WITH THE NEXT BEST CHANCE OF PRECIPITATION ARRIVING TUESDAY NIGHT AND INTO WEDNESDAY. && .AVIATION...26/06Z THUNDERSTORMS JUST ABOVE TO EXIT SRN IA INCLUDING AROUND KOTM. WITH LIGHT WINDS AND LINGERING LOW LEVEL MOISTURE FROM HUMID WED AND RECENT RAINS...EXPECT PATCHY FOG TO DEVELOP. HOWEVER EXTENSIVE MIDDLE CLOUD COVER FROM DEPARTING STORMS AND THUNDERSTORM COMPLEX OVER DAKOTAS SHOULD DEEP RADIATIVE COOLING FROM BEING TOO EXTREME SO ONLY MVFR FOG MENTION FOR NOW. CONFIDENCE IN DAKOTAS COMPLEX MAKING IT HERE RATHER LOW FOR THE TIME BEING...SO HAVE IGNORED AT 06Z. HOWEVER FULLY EXPECT ANOTHER ROUND OF THUNDERSTORMS SOMETIME TODAY OR THU EVENING. REALLY DO NOT HAVE A FEEL FOR LOCATION OR TIMING YET SO JUST MENTIONED CB RATHER THAN 6+ HOURS OF THUNDERSTORMS IN TERMINALS. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ RAD/FAB/BSS ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 316 AM CDT THU JUN 26 2008 .DISCUSSION... FORECAST CONCERNS...CONVECTIVE CHANCES/TRENDS AND SEVERE POTENTIAL FRIDAY AFTERNOON THROUGH FRIDAY NIGHT. ONLY SUBTLE CHANGES IN SENSIBLE WEATHER EXPECTED FOR TODAY...SO WILL FOLLOW A MODIFIED PERSISTENCE APPROACH TO THE FORECAST AND MOST GRID ELEMENTS TODAY. A BIT MORE OF A CAP EARLY THIS MORNING BASED ON RUC MODEL...SO HOPEFULLY WILL NOT SEE ANOTHER SUNRISE SURPRISE TOWARD DAWN...ISOLATED AS IT WAS YESTERDAY. OTHERWISE EXPECT A COUPLE LOCALES TO APPROACH/TOUCH THE CENTURY MARK ACROSS CENTRAL KANSAS THIS AFTERNOON. DESPITE MAXS IN THE LOW/MID 90S FOR THE REST OF THE AREA...IT WILL FEEL CLOSE TO 100 WITH COMBO OF HEAT AND HUMIDITY. CONVECTION THAT DEVELOPS NORTHWEST OF THE AREA THIS EVENING MAY CLIP NORTHERN PORTIONS OF THE FORECAST AREA TONIGHT...SO WILL KEEP A SLIGHT CHANCE IN FOR THOSE AREAS. HOWEVER...MAIN FOCUS FOR MORE ORGANIZED CONVECTION WILL COME LATER FRIDAY INTO EARLY SATURDAY MORNING...AS A STRONG SUMMER-TIME UPPER TROF AND THE ASSOCIATED COLD FRONT DROPS SOUTHEAST ACROSS THE MIDWEST. THIS TROF WILL DEEPEN ACROSS THE GREAT LAKES WITH A REINFORCING SHOT OF COOLISH/DRIER AIR SATURDAY NIGHT INTO SUNDAY. THE FRONT ON FRIDAY EVENING LOOKS TO ENCOUNTER A VERY UNSTABLE AIRMASS ACROSS EASTERN KANSAS...AND CONFIDENCE CONTINUES BUILD ON A SEVERE CONVECTIVE EPISODE...SO HAVE UPPED POPS INTO THE LIKELY CATEGORY FOR AREAS EAST OF THE KANSAS TURNPIKE FRIDAY NIGHT. STILL SOME QUESTION AS TO THE TIMING/SOUTHWARD MOVE OF THE FRONT...WITH THE NAM MORE PROGRESSIVE THAN OTHER MODELS. THIS MAY HAVE MORE OF AN IMPACT ON MAXS FOR CENTRAL KANSAS ON FRIDAY...AND FOR NOW WILL STILL KEEP THINGS QUITE TOASTY...HOWEVER AREAS OF SOUTH CENTRAL LOOK TO BE THE HOTTEST...ESPECIALLY FOR AREAS WEST AND SOUTHWEST OF GREATER WICHITA WHERE PERHAPS A DRIER SOUTHWEST FLOW AND SOME COMPRESSIONAL WARMING EFFECTS WILL ENHANCE MAX POTENTIAL LATE IN THE AFTERNOON. OTHERWISE...HAVE TEMPERED MAXS FOR THE WEEKEND...ESPECIALLY FOR SUNDAY...WITH MODEL CONSENSUS SUGGESTING RELATIVELY COOLER AIR WILL HOLD SWAY THRU THE WEEKEND NOW. DARMOFAL && .AVIATION... 06Z TAFS...ICT/SLN/HUT/CNU/RSL...VFR CONDITIONS ANTICIPATED OVER THE NEXT 24 HOURS. STRENGTHENING AND VEERING LOW-LEVEL JET TONIGHT MAY INITIATE A STRAY THUNDERSTORM SOMEWHERE ACROSS CENTRAL AND SOUTHEAST KANSAS TONIGHT...BUT PREDICTABILITY IS TOO LOW AND COVERAGE TOO SPARSE TO MENTION VCTS IN THE TAFS. OTHERWISE...STOUT SOUTHERLY WINDS WILL COMMENCE BY MID-MORNING THURSDAY...AS LOW PRESSURE STRENGTHENS ACROSS THE WESTERN HIGH PLAINS...AND A COLD FRONT GETS ITS ACT TOGETHER NORTHWEST OF THE AREA. KLEINSASSER && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 95 73 97 71 / 10 10 20 50 HUTCHINSON 96 72 98 69 / 10 10 30 50 NEWTON 95 73 97 70 / 10 10 30 50 ELDORADO 94 73 95 71 / 10 10 20 60 WINFIELD-KWLD 94 73 96 72 / 10 10 20 60 RUSSELL 100 71 95 66 / 10 20 40 20 GREAT BEND 99 71 97 67 / 10 10 40 30 SALINA 99 73 97 68 / 10 20 40 40 MCPHERSON 97 73 97 69 / 10 10 40 40 COFFEYVILLE 92 72 93 72 / 10 10 20 60 CHANUTE 92 72 93 72 / 10 20 20 60 IOLA 92 72 93 72 / 10 20 20 60 PARSONS-KPPF 92 72 93 72 / 10 10 20 60 && .ICT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 412 AM EDT THU JUN 26 2008 .SYNOPSIS... A WEAK COLD FRONT WILL WILL STALL ACROSS THE REGION THURSDAY. A WAVE OF LOW PRESSURE WILL TRACK ALONG THE FRONT THIS AFTERNOON AND MOVE EAST OF THE REGION ON FRIDAY. HIGH PRESSURE WILL THEN BUILD TOWARD THE AREA OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... MAIN CHALLENGES ARE POSITIONING OF THE FRONT AND THE POTENTIAL FOR SVR WX. DECIDED ON A BLEND OF THE GFS AND SREF FROM THIS AFTERNOON INTO TONIGHT. THE RUC13 AND GFS40 WAS USED TO START THINGS OFF THIS MORNING W/1ST BATCH OF LIGHT RAIN SHOWERS MOVING E AND EXITING INTO NEW BRUNSWICK. THE FRONTAL BOUNDARY IS FCST TO SLOWLY SAG S TODAY AS A WAVE OF LOW PRES MOVES IN ALONG THE BOUNDARY FROM CNTL CANADA. LOOKS LIKE THERE COULD BE THE POTENTIAL FOR 2 AREAS OF CONVECTION W/THE 1ST AREA GETTING STARTED LATER THIS MORNING INTO EARLY AFTERNOON ACROSS THE N AND W AND THEN A 2ND AREA FIRING UP ACROSS CNTL AND DOWNEAST AREAS. SATL IR IMAGERY SHOWING TO POTENTIAL FOR SOME INSOLATION THIS MRNG ACROSS THE N AND W IN BTWN S/WVS ALLOWING FOR DESTABILIZATION. CNTL AND DOWNEAST AREAS SHOULD BE ALLOWED TO HEAT UP THIS AFTERNOON. DWPTS ARE PROGGED TO INCREASE INTO THE LOWER AND MID 60S BY THIS AFTERNOON. GFS SOUNDINGS SHOWING MU CAPES HITTING 1000+ J/KG LATER THIS MORNING INTO EARLY AFTERNOON FOR THE N AND W AND THEN THINGS TRANSLATE INTO CNTL AND DOWNEAST BY MID-AFTERNOON. TTS HIT AROUND 50 W/KIS CLOSING IN 35 W/LIS DROPPING TO -4 TO -6. PWS AROUND 1.5". 0-6KM SHEAR IS ABOUT 25 KTS COUPLED W/INVERTED V IN LLVLS INDICATING DOWNDRAFT POTENTIAL. UA SHOWED 30-40 KT JETLET FROM 700-500 MBS TO CROSS THE REGION THIS MORNING AS WELL. ONE LACKING INGREDIENT IS STEEP LAPSE RATES. LAPSE ARE EXPECTED TO BE MEAGER W/VALUES AROUND 6.0 C/KM. SPC HAS BACKED OFF ON THE SLIGHT RISK POTENTIAL FOR OUR CWA AND NOW OUR CWA IS IN A GENERAL RISK. AFTER PHONE CHAT W/GYX...DECIDED TO ADD ENHANCED WORDING FOR HAIL AND GUSTY WINDS. INCREASING CONCERNS ARE THERE FOR THE POTENTIAL FOR HEAVY RAFL W/HIGH PWS AND LOW/MID FLOW PARALLELING THE FRONT. REGENERATION OF CELLS COULD LEAD TO THE POTENTIAL FOR SOME FLOODING ISSUES. THIS WILL NEED TO BE MONITORED. CONVECTION WILL WIND DOWN THIS EVENING AND HEAVY RAFL AXIS IS EXPECTED TO SHIFT INTO NEW BRUNSWICK AFT 06Z AS SFC LOW PASSES TO THE E. USED THE DAYCREW/S TEMPS AS THEY WERE MATCHING WELL W/THE LATEST OBS. ADJUSTMENTS WERE MADE TO THE WIND FIELDS TAKING A BLEND OF THE NAM12 AND GFS40. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... A COLD FRONT IS EXPECTED TO MOVE INTO NORTHERN PORTION OF THE STATE FRIDAY MORNING ALTHOUGH IT IS QUESTIONABLE HOW FAR TO THE SOUTH THE FRONT WILL MOVE FROM THAT POINT ON. FOR SATURDAY LOW PRESSURE ALOFT AND AT THE SURFACE APPROACH FROM THE GREAT LAKES. WILL GENERATE POP GRIDS WITH A BLEND OF THE SERF...GS40 AND NAM12. SKY GRIDS CREATED WITH A BLEND OF THE NAM12 AND GS40. FOR TEMPERATURE AND DEW POINT WILL INITIALIZE WITH GM OS. HAVE RAISED MAX TEMPERATURES A FEW DEGREES ABOVE GM OS. WILL MENTION SCATTERED THUNDERSTORMS FOR BOTH SATURDAY AND SUNDAY AFTERNOONS INTO THE EVENING. FOR PF HAVE USED A NAM12/GS40 BLEND. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... LOW PRESSURE IS EXPECTED TO APPROACH FROM THE WEST AT THE BEGINNING OF THIS PERIOD. THIS SYSTEM WILL SLOWLY MOVE TO THE NORTHEAST THRU TUESDAY AND WEDNESDAY. HAVE GENERATED GRIDS FOR THIS PERIOD USING GMOS. FOR SKY GRIDS HAVE MANUALLY ADJUSTED SOME PERIODS TO BETTER FIT POPS. WILL PUT MENTION OF THUNDER INTO SUNDAY AFTERNOON/EVENING PERIODS. && .AVIATION /07Z THURSDAY THROUGH MONDAY/... NEAR TERM: VFR TO START THINGS OUT TODAY AND THEN WE ARE EXPECTING CONDITIONS TO DROP INTO MVFR CATEGORY LATER THIS AFTERNOON W/RAFL AND POSSIBLE TSTMS. MVFR CONDITIONS LOOK TO HOLD INTO TONIGHT. LOOKING FURTHER OUT: EXPECT PERIODS OF MVFR/IFR CONDITIONS FROM FRIDAY INTO MONDAY. && .MARINE... NEAR TERM: NO HEADLINES. AS MENTIONED ABV...USED A GFS40/NAM12 BLEND FOR THE WINDS WILL INDICATES SPEEDS OF 10 KT INTO TONIGHT. WNAWAVE WAS LOADED FOR THE WAVE HEIGHTS AND THEN ADJUSTED DOWNWARD BY A FOOT AS IT IS ALREADY 1 FOOT OVER THE LATEST OBS. SHORT TERM: HAVE INITIALIZED WIND GRIDS WITH A 50/50 BLEND OF THE NAM12 AND THE GFS40. WIND SPEEDS LOOK REASONABLE AND WILL NOT MAKE ANY CHANGES. FOR WINDS AFTER 00Z SUNDAY WILL USE GMOS WINDS. FOR WAVES: HAVE INITIALIZED INTO SATURDAY WITH NAM VERSION OF SWAN. FOR REMAINDER OF PERIOD WILL INITIALIZE WITH WNA. IN GENERAL SEEMS TO BE HIGH BIAS FOR BEGINNING OF PERIOD SO WILL LOWER BY 1 FOOT. FOR SUNDAY INTO TUESDAY WNA RUNNING MUCH TOO HIGH AND HAVE LOWERED WAVE HEIGHTS SEVERAL FEET. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HEWITT SHORT TERM...MIGNONE LONG TERM...MIGNONE AVIATION...HEWITT MARINE...HEWITT/MIGNONE me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 530 AM EDT THU JUN 26 2008 .DISCUSSION... MAIN CONCERNS FOCUS ON TIMING OF CONVECTION ON FRIDAY AND POSSIBLE SVR STORMS...THEN LINGERING SHRA/TSRA INTO THE WEEKEND. WATER VAPOR LOOP AND RUC ANALYSIS CONTINUE TO SHOW ZONAL FLOW ACROSS THE NRN CONUS. SHORTWAVE RESPONSIBLE FOR LAST NIGHT`S CONVECTION HAS MOVED EAST OF THE AREA. IR SATELLITE NOW SHOWS CLEARING SKIES FROM THE WEST AS MID LVL RDGG AND SUBSIDENCE NOSE INTO THE AREA. HOWEVER...DEWPOINTS REMAIN FAIRLY HIGH (UPR 50S TO LOW 60S) AND FOG LINGERS OVER MUCH OF LAKE SUPERIOR EARLY THIS MORNING AND OVER THE SHORELINE AREAS. TODAY...EXPECT AREAS OF FOG NEAR THE LAKE SUPERIOR SHORELINE TO LIFT AFTER SUNRISE WITH SUNNY SKIES PREVAILING UNDER MID-LVL RIDGING AND SUBSIDENCE. 800 MB TEMPS NEAR 12C MIXING TO THE SFC SHOULD YIELD HIGHS IN THE LOWER 80S OVER THE WRN INTERIOR. LAKE BREEZES DEVELOPING WILL KEEP TEMPS COOLER (LOWER 70S) NEAR THE GREAT LAKES AND OVER THE ERN FCST AREA. TONIGHT...EXPECT DRY CONDITIONS TO CONTINUE UNDER THE INFLUENCE OF THE SFC HIGH ALTHOUGH THERE WILL BE SOME INCREASE IN WAA MID-HIGH LVL CLOUDS FROM THE SW LATE AHEAD OF NEXT INCOMING SHORTWAVE. EXPECT LOWS TO GENERALLY BE IN THE MID 50S WITH SLIGHTLY COOLER READINGS EAST WHERE SKIES SHOULD BE CLEAR MOST OF THE NIGHT. FRIDAY...GENERALLY FOLLOWED A BLEND OF THE NAM/UKMET/ECMWF AND SREF MODELS AS THE GFS AND EVEN THE GLOBAL GEM LOOK TO BE AFFECTED BY CONVECTIVE FEEDBACK. ALL THESE MODELS BRING THE LEAD SHORTWAVE INTO THE AREA ON FRI AHEAD OF AN UPR TROF/CLOSED LOW DEVELOPING OVER THE NRN PLAINS. 305K ISENTROPIC ASCENT ASSOC WITH THIS SHORTWAVE WILL SUPPORT THE INITIAL BATCH OF CONVECTION SPREADING SW TO NE ACROSS THE FCST AREA...MAINLY LATE FRI. BUMPED UP POPS TO LIKELY ACROSS WEST AND CENTRAL PORTIONS SINCE MODELS HAVE COME INTO BETTER AGREEMENT ON TIMING/COVERAGE OF SHRA/TSRA. STRONG MOISTURE INFLOW WITH PWAT INCREASING TO AOA 1.5 INCHES COULD SUPPORT HEAVY DOWNPOURS WITH THE SHOWERS. MUCAPE VALUES INTO THE 1000-1500 J/KG RANGE AND 0-6KM BULK SHEAR INTO THE 30-40 KT RANGE WILL BE ENOUGH TO SUPPORT SOME STRONGER STORMS. HOWEVER...HIGH FREEZING LEVELS (13-14 KFT) SHOULD LIMIT LARGE HAIL THREAT. SPC STILL HAS THE ENTIRE U.P IN A SLIGHT RISK OF SVR FOR THE DAY2 CONVECTIVE OUTLOOK. FRI NIGHT...AS THE MID/UPPER LEVEL LOW SINKS SLOWLY ESE TOWARD THE UPPER GREAT LAKES...A DRY SLOT WILL SPREAD THROUGH THE AREA REDUCING PCPN CHANCES. FOLLOWED THE PREFERRED SLOWER TIMING OF THE ECMWF AND SREF WITH THIS FEATURE SO KEPT IN SHRA/TSRA CHANCES WITH THE HIGHEST POPS OVER THE EASTERN FCST AREA. SAT INTO SUN...FOLLOWED THE NCEP PREFERRED GFS ENSEMBLE MEAN SOLN WITH MVMT OF THE UPR LOW WHICH IS SIMILAR TO THE OPERATIONAL 00Z ECMWF RUN. FCST 500 MB TEMPS OF -17C/-18C WITH STEEP LOW-MID LEVEL LAPSE RATES AND FORCING FROM SHORTWAVES ROTATING AROUND THE LOW WILL SUPPORT SCT SHRA/TSRA THROUGH THE PERIOD. BY SUN...WITH NRLY LOW LEVEL FLOW DEVELOPING...MUCH COOLER WEATHER IS EXPECTED ESPECIALLY ALONG LAKE SUPERIOR. THERE WILL BE CONTINUED CHCS FOR LIGHT RAIN OR SHOWERS BUT TSTM SHOULD CHANCES SHOULD BE DWINDLING. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... LATE AFTN VIS SATELLITE IMAGERY INDICATED FAIRLY EXTENSIVE FOG OVER WRN LAKE SUPERIOR. WITH UPSLOPING WNW WINDS PERSISTING THRU THE NIGHT AT KCMX...VFR WITH OCCASIONAL LIFR CONDITIONS IN FOG/STRATUS APPEAR LIKELY THERE. CONDITIONS SHOULD IMPROVE TO VFR WITHIN A FEW HRS AFTER SUNRISE. VFR CONDITIONS WILL THEN PREVAIL FOR THE REST OF THE FCST PERIOD. AT KSAW...SOME RADIATION FOG IS POSSIBLE A COUPLE OF HRS EITHER SIDE OF SUNRISE...BUT DOWNSLOPING WRLY FLOW SHOULD KEEP VIS FROM DROPPING BLO MVFR. VFR CONDITIONS WILL THEN PREVAIL AT KSAW FOR THE REMAINDER OF THE FCST PERIOD. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... AS HIGH PRESSURE CROSSES LAKE SUPERIOR TODAY THROUGH FRIDAY MORNING WINDS WILL LESS THAN 20 KNOTS. ANOTHER LOW PRESSURE TROUGH WILL MOVE FROM THE NORTHERN PLAINS TONIGHT AND INTO LAKE SUPERIOR ON FRIDAY NIGHT AND REMAIN THROUGH SATURDAY. PRESSURE GRADIENTS WILL TIGHTEN FOLLOWING THE LOW CAUSING WIND TO INCREASE TO 20 TO 25 KNOTS FOR A PERIOD OVER CENTRAL AND EAST EASTERN LAKE SUPERIOR. BY SUNDAY...THE LOW FILLING SLIGHTLY AND SLIDE SOUTHEASTWARD OVER LOWER MICHIGAN BY SUNDAY MORNING WILL CAUSE THE WINDS TO LESS AN 20 KNOTS FOR THE REMAINDER OF THE PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...VOSS AVIATION...ROLFSON/DLG MARINE...KF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 140 AM EDT THU JUN 26 2008 .AVIATION...THUNDERSTORMS ACROSS THE U.P. ARE SLIDING ESE EARLY THIS MORNING BUT SHOULD CLEAR KAPN/KPLN GIVEN STRONG CAPPING IN PLACE SOUTH OF THE STRAITS. BIGGEST FOCUS IS ON VISBYS/CIGS WITH PSEUDO-WARM FRONT SLIPPING NORTH THRU 12Z IN ADVANCE OF APPROACHING SFC COOL FRONT. ALREADY SEEING EXPANDING STRATUS DECK ALONG THIS BOUNDARY...WITH KTVC/KAPN STANDING THE BEST SHOT AT SEEING AT LEAST A TEMPORARY IFR CEILING/VISBY CREEP IN THRU SUNRISE. WILL ALSO BE WATCHING EXPANSIVE LAKE STRATUS DECK RUNNING THE LONG AXIS OF LAKE MICHIGAN...WHICH MAY BRIEFLY BE PUSHED INLAND TOWARD KTVC/KPLN AS INCOMING COOL FRONT SHIFTS WINDS NORTHWESTERLY TOWARD SUNRISE. OTHERWISE...JUST SOME SCATTERED (PERHAPS BROKEN FOR A TIME) CU TO FIRE THRU THE AFTN AS THERMAL TROUGH SLIPS OVERHEAD (SIMILAR TO UPSTREAM CONDITIONS YESTERDAY) BEFORE LOW LEVEL DRYING WINS OUT BY LATE AFTERNOON. COULD ALSO SEE BRIEFLY GUSTY WINDS FOR A TIME 15-21Z GIVEN MODESTLY MIXED BOUNDARY LAYER...THOUGH OVERALL LACK OF LOW LEVEL FLOW MAY ALSO ALLOW LAKE BREEZES TO PENETRATE TOWARD KAPN/KTVC BY MID AFTN. MPC/LAWRENCE && .DISCUSSION... /ISSUED 1010 PM EDT WED JUN 25 2008/ UPDATE...LATEST RUC ANALYSIS AND IR/WV/RADAR IMAGERY SHOW A WEAK SURFACE LOW TRANSVERSING OVER WESTERN LAKE SUPERIOR WITH WARM FRONT EXTENDING JUST NORTH OF THE LAKE SUPERIOR SHORELINE. SHOWERS AND THUNDERSTORMS...ALL SUB-SEVERE...CONTINUE TO DEVELOP JUST SOUTH OF THE SURFACE LOW WITHIN THE WARM SECTOR WITH SOME HELP FROM ADDED CONVERGENCE AS A RESULT OF LAKE BREEZES. THESE SHOWERS AND STORMS HAVE BEEN DISSIPATING AS THEY HEAD TOWARDS EASTERN ALGER COUNTY WHERE LOWER THETAE AIR RESIDES. ADDITIONAL THUNDERSTORMS ALSO HAVE BEEN REDEVELOPING AHEAD OF THE PARENT SHORTWAVE OVER THE ARROWHEAD OF MINNESOTA. FARTHER SOUTH...WEAK COOL FRONT/SURFACE TROUGH...WHICH EXTENDS ACROSS WESTERN WISCONSIN...HAS BEEN DORMANT IN REGARDS TO IGNITING CONVECTION DUE TO CAPPING ISSUES JUDGING BY 00Z GRB SOUNDING AS WARMING AIR SURGES NE AHEAD OF THE TROUGH. CLOSER TO HOME...A ROGUE SHOWER DEVELOPED OVER NE LOWER THIS EVENING BUT QUICKLY DISSIPATED LEAVING MOSTLY CLEAR TO PARTLY CLOUDY SKIES OVER MOST LOCALES. FOR THE REST OF THE NIGHT...THE WEAK SURFACE LOW WILL CONTINUE ITS TREK EAST AS HIGHER LOW LEVEL THETAE AIR WILL SURGE INTO THE REGION AHEAD OF ITS SURFACE TROUGH. STRONGEST (ALBEIT PRETTY MODEST) 700-500MB QG FORCING WILL RESIDE ACROSS EASTERN UPPER CLOSEST TO THE SHORTWAVE WITH A LITTLE 850-700MB -DIVQ CLIPPING NORTHERN LOWER TOWARDS THE TIP OF THE MITT. WITHIN THE THETAE AXIS...18Z NAM SHOWS 300-600 J/KG OF ELEVATED CAPE DEVELOPING BETWEEN 03-06Z...BUT CURRENT CONVECTION ACROSS THE U.P. APPEARS SURFACE BASED AND SHOULD DIMINISH SOMEWHAT AS DIURNAL INSTABILITY WANES. THE NAM ALSO TRIES TO DEVELOP A MODEST 25-30KT LLJ THAT POKES INTO EASTERN UPPER AFTER 03Z THAT CAN BOOST CONVERGENCE IN ADDITION TO THE CYCLONIC FLOW AROUND THE SURFACE LOW. THIS SEEMS TO POINT TOWARDS THE CONVECTION SURVIVING THE MARCH AS IT REACHES WHITEFISH POINT TO THE SOO LATER TONIGHT AND WILL BUMP UP POPS TO LIKELY. OVER NORTHERN LOWER...ABSENCE OF CONVECTION ALONG THE TROUGH THIS AFTERNOON MAKES ME THINK CAPPING WILL CONTINUE TO BE A PROBLEM FOR STORMS TO DEVELOP DESPITE AMPLE INSTABILITY ABOVE THE CAP. LACK OF UPPER LEVEL SUPPORT...AND WEAKENING SURFACE CONVERGENCE ALONG THE TROUGH DOES NOT HELP EITHER. HOWEVER...STILL A LITTLE WARY OF REMOVING PRECIP ALTOGETHER GIVEN ELEVATED INCOMING THETAE BOOST. SO WILL HEDGE AND GO ISOLATED THUNDER FOR NORTHERN LOWER OVERNIGHT. MPC && .PREV DISCUSSION... /ISSUED 329 PM EDT WED JUN 25 2008/ MID AFTERNOON OBSERVATIONAL AND NUMERICAL GUIDANCE ANALYSIS SHOWS PAIR OF EARLIER CONVECTIVELY INDUCED VORT LOBES...ONE OVER SOUTHERN LAKE MICHIGAN WITH THE OTHER OVER NORTH CENTRAL WISCONSIN...MAKING THEIR WAY EAST IN BROAD ZONAL WEST FLOW THAT LIES ACROSS THE NORTHERN CONUS AND SOUTHERN CANADA. AS FEARED...DESPITE SOMEWHAT INCREASING SUPPORT...AFTERNOON MIXING AND PRESENCE OF MID LEVEL CAP PREVENTING ANY SHOWER ACTIVITY OVER NORTHERN MICHIGAN (BESIDES SOME REMNANT SPRINKLES MAKING THEIR WAY ACROSS GLADWIN AND ARENAC COUNTIES FROM EARLIER DOWNSTATE CONVECTION). OTHERWISE... PLENTY OF SUNSHINE AND LIGHT SOUTHWEST FLOW ON BACKSIDE OF DEPARTING SURFACE RIDGE AXIS HAS LEAD TO A RATHER WARM SUMMER DAY...WITH AFTERNOON READINGS WELL INTO THE 70S AND LOWER 80S. FARTHER UPSTREAM...POTENTIAL NEXT WEATHER MAKER OF INTEREST IS NORTHERN MINNESOTA LOW AMPLITUDE SHORTWAVE AND ATTENDANT LOW PRESSURE/COLD FRONT MAKING STEADY EAST PROGRESS. FORECAST CONCERNS TONIGHT AND THURSDAY CENTER ON CONVECTIVE POTENTIAL AS THIS COLD FRONT PIVOTS SOUTHEAST ACROSS THE AREA. TONIGHT...THINKING THAT ANY LATE AFTERNOON ISOLATED SHOWERS AND STORMS THAT MANAGE TO DEVELOP WILL QUICKLY BE ON THE WANE...WITH ALL ATTENTION THEN TURNING TO UPSTREAM APPROACHING COLD FRONT. EXPECT CONVECTION TO QUICKLY FIRE THIS AFTERNOON ACROSS WESTERN UPPER MICHIGAN AND NORTH CENTRAL WISCONSIN AS CONVERGENCE AXIS WORKS ON 1500+ J/KG OF SURFACE BASED CAPE. SHOWERS AND STORMS WILL WORK EAST THIS EVENING FOLLOWING MOISTURE AXIS...PUSHING INTO EASTERN UPPER MICHIGAN LATER THIS EVENING. AFTER THAT...SEVERAL QUESTIONS ARISE AS OVERALL CONVERGENCE AND INSTABILITY WEAKENS AHEAD OF FRONTAL SYSTEM. THUS...FEEL COVERAGE AND INTENSITY OF SHOWERS AND STORMS WILL FOLLOW SUITE AS THEY DROP SOUTHEAST. THEREFORE...WILL TAPER POPS FROM NORTH TO SOUTH OVERNIGHT...NOT BRINGING IN CHANCE WORDING TO OUR SOUTHEAST ZONES UNTIL AFTER 09Z. AS FOR SEVERE WEATHER...REGION REMAINS OUT OF LATEST SPC SLIGHT RISK WORDING...WHICH SEEMS SUPPORTED BY BETTER BULK SHEAR REMAINING NORTH OF THE AREA AND RELATIVELY HIGH FREEZING LEVELS (>13.0 KFT). STILL...THINKING THE STRONGEST STORMS WILL BE CAPABLE OF SOME SMALL HAILS AND BRIEF GUSTY WINDS...ESPECIALLY LATER THIS EVENING ACROSS EASTERN UPPER MICHIGAN. THURSDAY...COLD FRONT CONTINUES TO DROP SOUTHEAST DURING THE MORNING AS PARENT LOW PUSHES INTO QUEBEC. WHILE MODELS REMAIN DRY DURING THE MORNING...HATE TO RULE OUT AT LEAST AN ISOLATED SHOWER OR STORM BEFORE FRONTAL PASSAGE. EARLY AFTERNOON HOURS COULD GET QUITE INTERESTING OVER FAR SOUTHEAST SECTIONS OF THE AREA IF COLD FRONT STALLS FROM INTENSE MORNING WARMING. MODIFYING A NAM-WRF SOUNDING (IGNORING OVERZEALOUS LOW 70 DEWPOINTS) YIELDS 1500+ J/KG MEAN LAYER CAPE. WILL KEEP LOW POP MENTION FOR THIS POSSIBILITY THROUGH 21Z BEFORE FRONT SAGS FAR ENOUGH SOUTH TO SUPPRESS CONVECTION. OTHER STORY WILL BE RATHER WARM TEMPERATURES...WITH READINGS PUSHING THE UPPER 80S SOUTHEAST OF WEST BRANCH. FARTHER NORTH...MID 70S TO LOWER 80S ARE EXPECTED...WITH TEMPERATURES SEVERAL DEGREES COOLER ALONG THE LAKE MICHIGAN SHORELINE. MSB THURSDAY NIGHT THRU FRIDAY NIGHT...STILL EXPECT A DRY THURSDAY NIGHT WITH WEAK RIDGING...SUBSIDENCE AND DRY AIR OVERHEAD. CONVECTIVE ACTIVITY PICKS UP AGAIN ON FRIDAY AS MOISTURE AND INSTABILITY INCREASE ACROSS THE WRN GREAT LAKES ALONG AND AHEAD OF A WARM FRONT. THIS FRONT IS ASSOCIATED WITH AN UNSEASONABLY STRONG LOW PRESSURE SYSTEM APPROACHING THE WRN GREAT LAKES REGION (MORE ON THIS SYSTEM BELOW). BEST INSTABILITY AND 850 THETA-E ADVECTION WILL OCCUR WELL SW OF OUR CWA OVER KANSAS...MISSOURI AND ILLINOIS (AN AREA THAT CERTAINLY DOES NOT NEED MORE RAIN). EXPECT BEST CHANCE OF SVR TSRA WILL BE IN THIS AREA WHERE STRONGER WIND FIELDS AND BETTER WIND SHEAR EXIST. STILL...CANNOT RULE OUT AN ISOLD SVR STORM FRIDAY AFTERNOON AND NIGHT WITH MODEST WIND SHEAR...CAPES APPROACHING 1000 J/KG AND THE 850 MB THETA E RIDGE AXIS JUST UPSTREAM. WILL MAINTAIN CHANCE OF SHRA/TSRA FOR FRIDAY AND LIKELY POPS FOR FRIDAY NIGHT. LOW TEMPS WILL FALL INTO THE UPPER 50S/LOWER 60S BOTH THURSDAY NIGHT AND FRIDAY NIGHT. HIGH TEMPS WILL WARM INTO THE UPPER 70S/LOWER 80S FRIDAY AFTERNOON. SATURDAY THRU WEDNESDAY...IMPRESSIVE UPPER LOW WILL DIVE SE OUT OF S CENTRAL CANADA INTO NRN MICHIGAN ON SATURDAY. SURFACE REFLECTION BECOMES VERTICALLY STACKED WITH THE DEEP CLOSED 500 MB LOW... RESULTING IN A VERY SLOW EASTWARD PROGRESSION AWAY FROM THE STATE FOR SUNDAY INTO MONDAY. AS MENTIONED ABOVE...SYSTEM IS UNSEASONABLY STRONG AND VERY DYNAMIC. IN ADDITION...LATEST MODELS STILL SUGGEST MAIN AREA OF CONVECTION ALONG AND AHEAD OF THE LOW AND COLD FRONT WILL IMPACT OUR AREA DURING PEAK HEATING SATURDAY AFTERNOON/EVENING. HAVE BOOSTED POPS TO LIKELY FOR SATURDAY AS MICHIGAN FINDS ITSELF WITHIN THE INSTABILITY AND MOISTURE AXES AHEAD OF THE SYSTEM. HAVE ALSO INCREASED POPS TO LIKELY FOR SATURDAY NIGHT AND SUNDAY AS THE STACKED LOW MOVES THRU NRN MICHIGAN AND THEN STALLS OVER LAKE HURON. CHANCE POPS SHOULD REMAIN IN THE FORECAST THRU MONDAY AS AMPLE LOW LEVEL MOISTURE...GOOD CYCLONIC FLOW AND SUFFICIENT INSTABILITY REMAIN OVER THE AREA AS THE 500 MB COLD POOL ARRIVES. MONDAY NIGHT THRU WEDNESDAY STILL LOOKS DRY AS HIGH PRESSURE/RIDGING/DRIER AIR SETTLE INTO THE REGION. EXPECT HIGH TEMPS MAINLY IN THE 70S AND LOWS IN THE 50S THRU THE PERIOD. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. LS...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 121 AM CDT THU JUN 26 2008 .UPDATE... RAISED OVERNIGHT MINS A FEW DEGREES AS LL HUMIDITY IS SLOW TO EXIT CWA. CLEARING HAS ALLOWED SFC T/TD TO QUICKLY APPROACH SATURATION ACROSS PARTS OF ARROWHEAD/RANGE/WEST TO CASS LAKE. HAVE INTRODUCED AREAS OF FOG OVERNIGHT HOWEVER RUC13 925H WINDS STILL NW AT 15-20KTS. NOT SURE IF THIS WILL IMPART ENOUGH TURBULENT KINETIC ENERGY TO RESTRICT ANY SIGNIFICANT AREAL COVERAGE OF FOG. AN ARE OF MID CLOUDS WILL SCOOT RAPIDLY ACROSS NRN CWA OVERNIGHT...ALSO TEMPERING RADIATIONAL COOLING SLIGHTLY. && .PREV DISCUSSION... /ISSUED 925 PM CDT WED JUN 25 2008/ UPDATE...THUNDERSTORMS THAT FIRED ALONG WARM FRONT DURING THE MID-AFTERNOON NEAR THE INTERNATIONAL BORDER HAS DECREASED OR HAS MOVED OUT INTO LAKE SUPERIOR. WITH THE SOLAR HEATING DECREASING AND THE CAP OVER AREA...THERE SHOULD BE LITTLE DEVELOPMENT OVERNIGHT AS RIDGE BUILDS INTO AREA. THIS WILL GIVE FORECAST AREA A BREAK DURING THE DAY THURSDAY BEFORE NEXT LOW PRESSURE APPROACHS THE AREA THURSDAY EVENING GIVING THE AREA ANOTHER SHOT FOR SEVERE WEATHER THURSDAY NIGHT AND FRIDAY. REST OF FCST UNCHANGED. STEWART PREV DISCUSSION... /ISSUED 308 PM CDT WED JUN 25 2008/ DISCUSSION... CURRENT SFC ANALYSIS DEPICTING LOW PRESSURE CENTERED NEAR KINL...WITH WEAK COLD FRONT DRAPED SOUTH THROUGH KHIB TO KROS. EARLIER OVERRUNNING CONVECTION FROM THIS MORNING HAS MOVED EAST OF THE ARROWHEAD REGION. SEVERE WX PARAMETERS THROUGH LATE THIS AFTERNOON FOCUSED ON THE ARROWHEAD REGION...AS WELL AS NW WI...THOUGH FORCING FOR CONVECTION QUESTIONABLE OVER NW WI. MSAS ANALYSIS DEPICTING TONGUE OF HIGHEST POTENTIAL TEMPS AND TD`S EXTENDING NORTH THROUGH CENTRAL ST LOUIS COUNTY. LATEST RUC SOUNDINGS FROM KELO DEPICTING LI VALUES -3 TO -4 THROUGH LATE THIS AFTERNOON. DEEP LAYER SHEAR OF 40 TO 50 KTS WILL BE CONDUCIVE FOR SEVERE THUNDERSTORMS. LOW PRESSURE AND ATTENDANT COLD FRONT MOVE EAST OVERNIGHT... ALLOWING FOR HIGH PRESSURE TO BUILD IN. A WARM AND PLEASANT DAY ON TAP FOR THURSDAY BEFORE NEXT SYSTEM AFFECTS THE NORTHLAND. STRONG WAVE PROGGED TO DROP SOUTHEASTWARD FROM CANADA ON FRIDAY. RETURN FLOW FROM THE SOUTH OVERNIGHT THURSDAY...AND APPROACHING LOW PRESSURE WILL TRIGGER TS OVER THE DAKOTAS THURSDAY NIGHT. SRLY LLJ INCREASES TO 50KTS FRI MORNING ACROSS CENTRAL MN...WITH ONGOING SHOWERS AND THUNDERSTORMS QUICKLY PROPAGATING THROUGH CWA. ATTM... BEST CHANCE FOR SEVERE IS ACROSS SW CWA...WHERE MAX INSTABILITY AND LIFT IS FOCUSED. SEE DAY 2 OUTLOOK ISSUED BY SPC FOR DETAILS. INTRODUCED LIKELY POPS ON FRIDAY...AS MODELS ARE IN DECENT AGREEMENT ON PLACEMENT OF SYNOPTIC FEATURES. CONFIDENCE NOT AS GREAT FRI EVENING...AS GFS SHOWING STRONGER DOUBLE BARREL LOW DEVELOPING AND DRY SLOT PUNCHING INTO SRN ZONES...WITH ECMWF SLIGHTLY WEAKER WITH SFC FEATURE. WEEKEND SHAPING UP TO BE COOL AND WET AS UPPER LOW BECOMES QUASI STATIONARY OVER THE UPPER GREAT LAKES. ECMWF SLIGHTLY FASTER WITH MOVING THE SYSTEM OUT BY SUNDAY...WITH GFS HANGING ON THROUGH EARLY MONDAY. EITHER WAY...SHOULD SEE BELOW NORMAL TEMPS THIS WEEKEND. AVIATION... SCATTERED THUNDERSTORMS WITH GUSTY WINDS AND MVFR/IFR VSBYS/CIGS ARE EXPECTED TO DEVELOP THIS AFTERNOON ALONG A COLD FRONT TRACKING SOUTHEAST ACROSS THE NORTHLAND. THE STORMS WILL MOVE SOUTHEAST WITH THE FRONT THIS EVENING...AND SHOULD MOVE SOUTH OF THE AREA AFTER MIDNIGHT. THERE IS A SLIGHT RISK THAT SOME STORMS MAY BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS. HIGH PRESSURE WILL BUILD IN OVER THE REGION BY THURSDAY RESULTING IN DRY CONDITIONS. SKIES SHOULD CLEAR OUT TONIGHT AND WINDS WILL BECOME LIGHT...ALLOWING FOR THE FORMATION OF FOG WITH IFR/MVFR VSBYS LATE TONIGHT AND EARLY THURSDAY MORNING. && POINT TEMPS/POPS... DLH 80 53 69 54 / 10 20 60 30 INL 82 56 74 54 / 10 20 60 40 BRD 83 60 75 56 / 10 50 50 30 HYR 83 55 74 55 / 10 40 60 30 ASX 79 56 73 54 / 10 10 60 40 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ CANNON mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 430 AM CDT THU JUN 26 2008 .DISCUSSION... /404 AM CDT THU JUN 26 2008/ SHORT DISCUSSION THIS MORNING DUE TO ACTIVE WEATHER. BROKEN LINE OF THUNDERSTORMS WILL CONTINUE SOUTH THROUGH SUNRISE. RUC IS INDICATING THAT MOST OF THE INSTABILITY IS BACK TOWARD SOUTHWEST MISSOURI...SO THINK THE PRIMARY THRUST OF THE STORMS WILL BE IN THAT DIRECTION. KEPT LIKELY/CATEGORICAL POPS GOING THRU 12Z...FADING TO MID-HIGH LIKELY AFTER 12Z. MODELS DEVELOP PLENTY OF CAPE THIS AFTERNOON IN THE HEAT OF THE DAY...AND WITH BOUNDARIES LINGERING FROM THIS MORNING`S STORMS FELT CHANCE POPS WERE PRUDENT FOR THE AFTERNOON. TONIGHT...MODEL QPF AND POPS HAVE BEEN PERFORMING POORLY AT BEST OVER THE PAST COUPLE OF NIGHTS. HAVE DECIDED TO MORE OR LESS IGNORE THE LESS THAN 20 PERCENT POPS GUIDANCE IS GIVING US IN NORTHERN AREAS AND HAVE GONE WITH HIGH CHANCE INSTEAD. THE THIRD IN THIS SERIES OF SMALL SHORTWAVES WILL MOVE FROM THE PLAINS INTO THE MIDWEST TONIGHT. OPERATIONAL MODELS ARE HINTING THAT THE FLOW WILL BECOME A BIT MORE ZONAL TONIGHT WHICH WOULD KEEP ALL OF THE PRECIP ASSOCIATED WITH THIS VORT NORTH OF THE CWFA...HOWEVER I HAVE LITTLE OR NO CONFIDENCE IN THIS SOLUTION BASED ON THE PAST COUPLE OF NIGHT`S PERFORMANCE. AM THINKING THAT THIS WILL BE TOO FAR NORTH AND THAT WE COULD GET THE SOUTHERN END OF AN MCS AS IT MOVES THROUGH CENTRAL IOWA INTO NORTHERN ILLINOIS. AS PREVIOUSLY STATED...HAVE INCREASED POPS TO HIGH CHANCE ACROSS THE NORTHERN TIER OF COUNTIES IN THE CWFA. DID NOT GO TOO HIGH ON QPF AT THIS TIME AS CONFIDENCE IS LOW...BUT DID GO HIGHER THAN HPC GUIDANCE SUGGESTED. FRIDAY NIGHT STILL LOOKS VERY WET AS THE COLD FRONT MOVES INTO MISSOURI ACCORDING TO ALL GUIDANCE. ATMOSPHERE WILL BE VERY MOIST AND UNSTABLE WITH PWATS IN EXCESS OF 2 INCHES AHEAD OF THE FRONT. HAVE INCREASED POPS SLIGHTLY TO 60-70% ACROSS THE MAJORITY OF THE AREA...AND BUMPED UP QPF SLIGHTLY AS WELL. HAVE MADE LITTLE OR NO CHANGE TO THE REMAINDER OF THE FORECAST BEYOND SATURDAY FOR THIS PACKAGE. CARNEY && .AVIATION... /1033 PM CDT WED JUN 25 2008/ FOR THE 06Z TAFS...WRMFNT HAS PUSHED N OF THE TAF SITES SO S-SWLY SFC WNDS WL CONT THIS TAF FSCT PD. MCS HAS DVLPD OVER ERN IA AND THIS SHOULD MOVE E-SEWD GRAZING NERN MO AND W CNTRL IL LT TGT. MAY INCLUDE VCTS IN UIN AFTER 07Z THU AS TSRA MAY GET CLOSE TO THE AIRPORT AS THEY CONT TO MOVE AND DVLP E-SEWD WITH TIME. WILL PROBABLY GO SKC IN COU..STL AND SUS LT TGT AS EVEN HI LVL CONVECTIVE DEBRIS CLOUDINESS SHOULD REMAIN N OF THESE SITES. FEW- SCT DIURNAL CUMULUS CLOUDS SHOULD DVLP BY LT THU MRNG. MAY BE ISOLATED CONVECTION ALONG TSRA OUTFLOW BNDRY FROM LT NGT AND EARLY MRNG CONVECTION BUT WILL LEAVE TAFS DRY FOR NOW ON THU AS THE PROBABILITY OF TSRA AT ANY OF THE TAF SITES LOOKS LOW. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...FLASH FLOOD WATCH UNTIL NOON CDT TODAY FOR LINCOLN. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 1252 AM CDT THU JUN 26 2008 .AVIATION...06Z KGRI TAF. VFR CONDITIONS FOR THIS FORECAST. WIND SHOULD REALLY START MIXING AND GUSTING FROM THE SOUTH BY THIS AFTERNOON. STORMS THEN MOVE INTO THE AREA AT THE END OF THE PERIOD...THIS EVENING AND TONIGHT. && .PREV DISCUSSION... /ISSUED 942 PM CDT WED JUN 25 2008/ DISCUSSION...DUE TO THE ONGOING CONVECTION IN NORTHWESTERN KANSAS...THIS LOOKS LIKE IT IS HOLDING TOGETHER AND COULD AFFECT PARTS OF OUR KANSAS COUNTIES AT LEAST IN THE EARLY OVERNIGHT HOURS THAT DID NOT MENTION THUNDERSTORMS IN THE PREVIOUS FORECAST. THE INCREASING LOW-LEVEL JET SHOULD HELP KEEP THESE STORMS GOING OVERNIGHT AS WELL. AS FAR AS MODELS ARE CONCERNED...QPF FIELDS ARE GENERALLY WORTHLESS AND HAVE BEEN IGNORED. PREV DISCUSSION... /ISSUED 355 PM CDT WED JUN 25 2008/ SHORT TERM...FOR TONIGHT THROUGH THURSDAY NIGHT. LATEST WATER VAPOR IMAGERY REVEALS A FAIRLY ZONAL FLOW REGIME ACROSS THE NORTHERN HALF OF THE CONUS WITH SEVERAL SMALL BUT POTENT WAVES EMBEDDED WITHIN THIS UPPER FLOW PATTERN. ONE OF THESE WAVES IS CURRENTLY SLIDING OUT OF THE HIGH PLAINS WHILE A SECOND WAVE IS SEEN PUSHING INTO THE ROCKIES. RECENT OBJECTIVE SURFACE ANALYSIS SHOWS TWO BOUNDARIES OF INTEREST ACROSS THE AREA WITH A DIFFERENTIAL HEATING BOUNDARY STRETCHING FROM NEAR MCCOOK TO AROUND GRAND ISLAND WHILE WEAK SURFACE TROUGH IS SEEN STRETCHING FROM NORTHERN IOWA INTO NORTH CENTRAL NEBRASKA. LOOKING AT RUC ANALYSIS...ML CAPES OF 3000 TO AS HIGH AS 4500 J/KG ARE SEEN FROM NORTHERN KANSAS INTO CENTRAL NEBRASKA ALTHOUGH MOST OF THIS AREA CONTINUES TO HAVE MODEST TO STRONG INHIBITION. HOWEVER...WEAKER INHIBITION IS SHOWN ACROSS NORTH CENTRAL NEBRASKA AND AGAIN ACROSS NORTHWESTERN KANSAS. TAKING A LOOK AT VISIBLE SAT IMAGERY IN THESE WEAKER INHIBITION AREAS...A SMALL CLUSTER OF CU IS VISIBLE NEAR KGLD BUT LITTLE IS SHOWN ACROSS NORTH CENTRAL NEBRASKA. MAIN QUESTION AS THE AREA HEADS INTO THIS EVENING TO OVERNIGHT IS WHERE DEEP CONVECTION MAY DEVELOP. INITIAL PROBLEM WITH DEVELOPING DEEP CONVECTION ACROSS THE AREA LATE THIS AFTERNOON TO EARLY EVENING IS THAT FORCING FROM THE FIRST WAVE MOVING THROUGH THE REGION NOW...IS SHOWN TO SLIDE EAST OF THE FORECAST AREA BY EARLY EVENING. GIVEN THE TIMING OF THIS WAVE PRODUCING INCREASING MID LEVEL SUBSIDENCE ALONG WITH A LACK OF ANY CONVECTIVE DEVELOPMENT OVER THE REGION THIS AFTERNOON...CONFIDENCE IS LOW THAT DEEP CONVECTION WILL DEVELOP THROUGH EARLY EVENING. WILL OPT TO KEEP A SLIGHT CHANCE OVER MOST OF THE CWA BUT THIS MAY NEED TO BE REMOVED BY THE EVENING SHIFT IF NOTHING DEVELOPS. IF SOMETHING DOES DEVELOP...SEVERE THREAT LOOKS MARGINAL AS EFFECTIVE DEEP LAYER SHEAR WILL REMAIN WEAK AT 15 TO 25 KNOTS AT BEST. WILL KEEP MENTION OF SEVERE BUT WILL DECREASE MAX HAIL SIZE DOWN TO PENNY TO QUARTER SIZE. HOWEVER...AS THE EVENING PROGRESSES INTO THE OVERNIGHT HOURS A 30 TO 40 KT LLJ IS SHOWN TO NOSE INTO THE AREA WITH WHATEVER CONVECTION REMAINS ACROSS THE HIGH PLAINS SLIDING EAST INTO THE CWA. COVERAGE OF STORMS LOOKS SMALL...BUT WILL KEEP A SLIGHT CHANCE OVER MOST OF THE CWA THROUGH THE NIGHT. THURSDAY AFTERNOON INTO THURSDAY NIGHT IS THEN SHAPING UP TO BE AN ACTIVE TIME FRAME ACROSS THE REGION. A WEAK AREA OF LOW PRESSURE IS SHOWN BY THE MODELS TO SPIN UP OVER NORTH CENTRAL NEBRASKA WITH A WARM FRONT SEEN EXTENDING EAST ACROSS NORTHERN NEBRASKA WHILE A DRYLINE STRETCHES SOUTH ACROSS FAR WESTERN SECTIONS OF THE FORECAST AREA GENERALLY NEAR HIGHWAY 283. DEEP LOW LEVEL MOISTURE WILL BE AVAILABLE AHEAD OF THE DRYLINE AND ON EITHER SIDE OF THE WARM FRONT. THIS IS SHOWN TO PRODUCE ML CAPES OF 2000 TO 2500 J/KG NEAR THE DRYLINE AND 3000 TO 3500 J/KG NEAR THE WARM FRONT. A HEALTHY SHORT WAVE IS SHOWN TO RIDE OUT OF THE ROCKIES INTO THE PLAINS DURING THE AFTERNOON AND EXPECT THIS TO TRIGGER ISOLATED CONVECTIVE DEVELOPMENT ALONG THE DRYLINE AND MORE SCATTERED DEVELOPMENT JUST NORTH OF THE CWA NEAR THE WARM FRONT. SEVERE CONVECTION WISE...EFFECTIVE DEEP LAYER SHEAR WILL BE RATHER WEAK ALONG DRYLINE BY MID TO LATE AFTERNOON WITH VALUES OF 10 TO 25 KNTS AT BEST. THIS SHOULD KEEP CONVECTION ON THE WEAKER SIDE OVER THIS PORTION OF FORECAST AREA. HOWEVER...WITH SURFACE WINDS BACKING AROUND TO A MORE EASTERLY DIRECTION CLOSER TO THE WARM FRONT...EFFECTIVE DEEP LAYER SHEAR OF 25 TO NEAR 40 KNTS SHOULD SUPPORT GOOD CELL ORGANIZATION AND POSSIBLE ROTATION. TORNADO THREAT LOOKS MINIMAL BUT LARGE HAIL THREAT LOOKS POSSIBLE MAINLY NORTH OF HIGHWAY 92. TEMPERATURE WISE...A VERY WARM AFTERNOON LOOKS ON TAP WITH HIGHS RANGING FROM THE LOWER TO MID 90S NEAR ORD TO OSCEOLA...TO THE MID 90S TO AROUND 100 ACROSS NORTH CENTRAL KANSAS. LONG TERM...12Z FRIDAY THROUGH WEDNESDAY. A COLD FRONT WILL BE ON TOP OF THE CWFA FRIDAY MORNING...AS MAY LEFTOVER SHOWERS AND DEBRIS CLOUDS FROM ANY THURSDAY NIGHT MCS ACTIVITY. THE MODELS ARE ALL VERY SIMILAR IN TIMING THE FRONT THROUGH ALL BUT THE FAR SOUTHEAST CFWA AS EARLY AS MIDDAY...AND THAT MAY BE TOO SLOW IF CONVECTION THURSDAY NIGHT PUSHES HAS ANY SAY. POINT IS...WITH CLOUDS LINGERING...AND FRONT ON THE MOVE...THE BEST CHANCE FOR ANY PRECIPITATION FRIDAY WILL BE EAST/SOUTHEAST CWFA. KEPT A SMALL RISK FOR FRIDAY NIGHT...IN CASE POST FRONTAL ELEVATED PRECIPITATION CAN FORM...WHICH IT OFTEN DOES FOR A TIME IN THESE SITUATIONS. THE WEEKEND LOOKS ADMIRABLE WEATHER WISE. ANOMALOUSLY DRY AIR IS FORECAST TO COME INTO THE CENTRAL PLAINS BEHIND COLD FRONT FRIDAY...DRIVEN BY GREAT LAKES REGION LOW PRESSURE. PWAT VALUES ARE FORECAST TO BE IN THE LOWER HALF OF CLIMATOLOGY VALUES. THOUGH DEWPOINTS MAY BE HELD UP SLIGHTLY WITH EVAPOTRANSPIRATION AND RECENT RAINFALL ISSUES...IT SHOULD STILL FEEL MUCH MORE PLEASANT WITH DEWPOINTS IN THE 50S FOR MOST AREAS. NEXT SHOT FOR A STORM OR TWO COULD COME MONDAY EVENING IN THE WESTERN ZONES...AS A STORM MAY FLOUNDER IN FROM THE HIGH PLAINS. LITTLE BETTER RISK OF STORMS POSSIBLE TUESDAY/WEDNESDAY...AS THE RIPPLE EFFECT RETURNS WITH A WEAK WAVE CUTTING THROUGH THE RIDGE. TEMPERATURES SHOULD GRADUALLY WARM A FEW DEGREES EACH BEGINNING SATURDAY. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 409 AM EDT THU JUN 26 2008 .SYNOPSIS... A WARM FRONT WILL PUSH THROUGH PENNSYLVANIA EARLY TODAY. A SLOW MOVING COLD FRONT WILL LIKELY MOVE THROUGH THE REGION LATE IN THE WEEKEND. AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL LIKELY BE OVER THE AREA EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DYING MCS MOVING INTO CENTRAL PA EARLY THIS AM. HAVE RAISED POPS SIGNIFICANTLY OVR MUCH OF THE REGION EARLY THIS MORNING BASED ON RADAR TRENDS. LATEST RUC13 AND SREF DATA SUGGEST THIS WEAKENING AREA OF SHWRS...AND PERHAPS A RUMBLE OF THUNDER...WILL PUSH EAST OF THE REGION BY ARND 15Z WITH PASSAGE OF LL JET. IN WAKE OF MCS...WARMER AND MORE HUMID AIRMASS OVERSPREADS THE REGION LATER TODAY...AS SFC WARM FRONT PUSHES NORTH OF PA. EARLY CLOUDS SHOULD GIVE WAY TO BRIGHTENING SKIES BY MIDDAY...RESULTING IN SREF CAPES NR 2000 J/KG BY AFTN. ALTHOUGH NEARLY ALL OF CENTRAL PA IS UNDER A SLIGHT RISK FOR SVR WX THIS AFTN...LATEST ENS DATA SUGGESTS NORTHERN PA IS UNDER THE GREATEST RISK...AS CORE OF STRONGEST MID LVL WINDS FCST TO PASS OVR UPSTATE NY. FURTHER SOUTH...SREF 0-6KM SHEAR VALUES BLW 20KTS SUGGEST A MUCH LOWER CHC FOR ORGANIZED SVR WX ACROSS SOUTHERN PA. HIGHEST /CHC/ POPS THIS AFTN WILL BE PLACED OVR THE ALLEGHENY HIGHLANDS...WHERE ELEVATED HEAT SOURCE/TOPOGRAPHIC FORCING MOST LIKELY TO INITIATE CONVECTION. 850 TEMPS ARND 18C SUGGEST HIGHS ACROSS THE LOWER SUSQ VALLEY COULD HIT 90F TDY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... SCT EVENING CONVECTION SHOULD DWINDLE AFTER SUNSET THIS EVENING. WEAK SHORTWAVE PASSING THRU SOUTHERN ONTARIO/QUEBEC WILL PUSH A DYING COLD FRONT INTO NORTHERN PA. ACROSS SOUTHERN PA...DIURNAL HEATING OF MOIST/UNSTABLE AIRMASS SHOULD YIELD SCT AFTN PULSE TYPE CONVECTION ON FRIDAY. SREF 850 TEMPS SUPPORT HIGHS ARND 90F IN THE VALLEYS SOUTH OF I-80. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... BETTER PROBABILITIES FOR SHOWERS AND T-STORMS...SOME POSSIBLY SVR...STATEWIDE ON SATURDAY AS A SHARP SLOW-MOVING COLD FRONT APPROACHES THE REGION AHEAD OF DIGGING UPPER LVL TROF OVR THE WESTERN GRT LKS. FRONT GRADUALLY CROSSES AREA SAT NITE/SUNDAY...AS UPPER-LVL TROF CLOSES OFF OVER NORTHERN GRT LKS. WILL CARRY SHWRS AND T-STORMS INTO SUNDAY...ESPECIALLY ACROSS EASTERN PA. MEDIUM-RANGE MODELS PARK UPPER-LVL TROF OVER THE NORTHEASTERN UNITED STATES EARLY NEXT WEEK...RESULTING IN RELATIVELY COOL CONDS. GIVEN COLD TEMPS ALOFT...CAN/T RULE OUT SCT DIURNAL CONVECTION...ESPECIALLY ACROSS THE HIGHER TERRAIN. UPPER TROF LIKELY TO LIFT OUT BY MIDWEEK...RESULTING IN FAIR AND WARMER CONDS. && .AVIATION /07Z THURSDAY THROUGH MONDAY/... LARGE COMPLEX OF SHOWERS AND A FEW THUNDERSTORM WILL MOVE ACROSS CENTRAL PA OVERNIGHT. SYSTEM IS GENERALLY WEAKENING FROM WHAT IT WAS OVER OHIO LAST EVENING. SHOWERS WILL MOVE INTO SWRN TERMINALS KJST/KBFD AND CENTRAL KUNV BETWEEN 06Z AND 08Z AND CONTINUE THRU SUNRISE. EXPECT MDT TO OCNL HVY RAIN WITH A FEW LTG STRIKES. MAIN AVIATION IMPACT WILL BE MVFR/IFR CIGS/VSBYS DUE TO THE RAIN. A BRIEF WIND GUST TO 30KTS ALSO POSSIBLE...ESP NEAR THE ONSET OF PCPN. PCPN SHOULD REACH KIPT AND KMDT AFTER 10Z...BUT AS SYSTEM CONTINUES TO WEAKEN...EXPECT CIG/VSBY DETERIORATION TO BE LESS AT THESE LOCS. LEFTOVER SHRA/TSRA SHOULD DIMINISH IN COVERAGE INTO MID MORNING AS THE SYSTEM SLIDES INTO THE EASTERN PART OF THE STATE. XPECT SOME MVFR CIGS AND OCNL MVFR VIS THRU LATE MORNING. VFR FLYING TO RETURN BY THE AFTN WITH SCT- BKN CU. LATE DAY CLEARING MAY LEAD TO SOME ISOLD SHRA/TSRA ESP ACROSS THE NRN TIER CLOSE TO A DIFFUSE FNTL BNDRY. WEST TO EAST ZONAL PATTERN WILL KEEP ACTIVE WX THRU FIRST HALF OF WEEKEND. PERIODS OF DRY/WET WX FRI-SUN AS MODELS HINT AT PRODUCING A QUASI-STATIONARY BNDRY FROM SOUTHERN MO ARCHING NE TOWARDS DELMARVA. WHICH WOULD SUPPORT THINKING WITH CHC/S OF SHRA/TSRA EACH OF THE NEXT SEVERAL DAYS. MID LVL SHORTWAVE AND ASSOCIATED COLD FRONT SLIDES INTO GRT LKS SUN EVE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...FITZGERALD NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD LONG TERM...FITZGERALD/RXR AVIATION...GARTNER/STEINBUGL pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 941 AM MDT THU JUN 26 2008 .UPDATE... SATELLITE IMAGERY AND MORNING SOUNDING DATA INDICATE MID LEVEL MOISTURE CREEPING TOWARD THE AREA FROM THE SOUTH. RUC ANALYSIS ALSO DEPICTS A WEAK SHORTWAVE TROUGH OVER THE FOUR CORNERS AREA AND CENTRAL UTAH THIS MORNING WHICH LOOKS REASONABLE GIVEN THAT THUNDERSTORMS HAVE ALREADY FORMED OVER THE MOUNTAINS OF SOUTHEAST UTAH. THIS WAVE SHOULD MIX OUT THE WEAK SUBSIDENCE INVERSION NEAR 500MB ON THE GJT SOUNDING AND WITH DAYTIME HEATING EXPECT ISOLATED THUNDERSTORMS TO DEVELOP ACROSS THE NORTHERN HIGH TERRAIN AS WELL AS THE SOUTH. WILL MAKE ADJUSTMENTS TO POP AND SKY GRIDS IN MORNING UPDATE...OTHERWISE THE GOING FORECAST LOOKS FINE. && .PREVIOUS DISCUSSION...SHORT TERM...TODAY THROUGH FRIDAY NIGHT... TWO MINOR FEATURES TO WATCH TODAY...ONE FROM THE GREAT BASIN AND THE OTHER OVER ARIZONA. SHORT WAVE MOVING ACROSS THE NRN INTERMOUNTAIN REGION DRAGS A WEAK COOL FRONT ACROSS THE NRN GREAT BASIN. THIS IS THE TIME OF YEAR COOL FRONTS STRUGGLE TO PENETRATE INTO OUR FORECAST AREA. THIS IS NO EXCEPTION AS THE SHORT WAVE DOES NOT HAVE A DIGGING JET ON THE BACK SIDE UNTIL IT REACHES THE NRN PLAINS. HOWEVER...THE MODELS DO INDICATE THAT THE SHALLOW COOL FRONT DOES MOVE SOUTH OF THE COLORADO AND WYOMING BORDER THIS EVENING. THIS MAY NOT HAVE MUCH OF AN IMPACT ON SENSIBLE WEATHER EXCEPT TO ENHANCE AFTERNOON BREEZES AROUND 15 TO 20 MPH OVER THE NRN VALLEYS. WEAK CLOSED LOW CIRCULATION OFF THE SRN CALIFORNIA COAST IS SENDING A STREAM OF MOISTURE NORTHWARD OVER SRN AND ERN ARIZONA. LOW LEVELS REMAIN DRY BUT SUFFICIENT MID TO HIGH LEVEL MOISTURE FOR ISOLATED THUNDERSTORMS OVER THE SAN JUAN AND WEST ELK MOUNTAINS. THE GFS AND SREF MODEL SUGGEST THAT ISOLATED NOCTURNAL THUNDERSTORMS MAY OCCUR OVER SW COLORADO. THIS CANNOT BE DISCOUNTED AS ISOLATED NOCTURNAL THUNDER OVER MONTEZUMA COUNTY FROM ARIZONAS CONVECTIVE DEBRIS IS NOT UNUSUAL. ON FRIDAY...DEFORMATION AXIS WILL BE ORIENTED WEST-EAST OVER SRN UTAH AND SRN COLORADO. NORTH OF THIS AXIS...THE PACIFIC HIGH CENTERED OVER THE NRN GREAT BASIN HAS A TENDENCY TO CAP CONVECTIVE POTENTIAL. INSTABILITY LOOKS VERY MARGINAL...BUT A FEW STORMS WILL STILL OCCUR OVER THE HIGH MOUNTAINS OF THE WEST SLOPE. .LONG TERM...SATURDAY THROUGH THURSDAY... HOT AND MOSTLY DRY CONDITIONS CONTINUE FOR THESE PERIODS WITH SOME UNCERTAIN PROMISE OF INCREASED MOISTURE BY MID NEXT WEEK. SATURDAY: WITH THE RIDGE AXIS TO OUR WEST...FROM EL PASO TO THE 4- CORNERS TO BOISE...A WARM NW FLOW CONTINUES. MOISTURE VERY LIMITED FOR NO MENTION OF THUNDERSTORMS FOR NOW. SUNDAY-MONDAY: RIDGE AXIS TRANSLATES OVERHEAD AS THE WEST-COAST TROUGH GETS ACTIVE. THIS ADD A FEW DEGREES TO ALREADY HOT AFTERNOONS. A STRENGTHENED MID-LEVEL SUBSIDENCE INVERSION WILL LIMIT THUNDERSTORM ACTIVITY. WINDS ALOFT VERY LIGHT WITH SFC WINDS TERRAIN DOMINATED. TUESDAY-THURSDAY: RIDGE GETS SQUASHED JUST A BIT AS THE WEST-COAST TROUGH EJECTS ENERGY ACROSS THE GREAT BASIN. RESULTING SW FLOW PROMISES SOME SLIGHT MOISTURE INCREASE FAVORING THE SOUTHERN MOUNTAINS WITH THUNDERSTORM POTENTIAL. SLIGHTLY COOLER TEMPERATURES POSSIBLE WITH THIS MOISTURE BUT DID NOT FULLY FOLLOW MEX TREND TOWARDS CLIMATOLOGY. && .AVIATION... VFR PREVAILS WITH ISOLATED THUNDERSTORMS FORMING OVER THE HIGH TERRAIN. MOST STORMS WILL DISSIPATE WITH SUNSET...BUT A FEW STORMS WILL BE POSSIBLE THROUGH THE NIGHT OVER EXTREME SOUTHWEST COLORADO. GUSTY ERRATIC WINDS WILL BE POSSIBLE WITH THE STORMS. && .HYDROLOGY... THE VERY WARM TEMPERATURES ACROSS THE AREA FOR THE NEXT SEVERAL DAYS WILL CONTINUE TO EAT AWAY AT THE HIGH MOUNTAINS SNOWPACK WITH RUNOFF AND RIVER AND STREAM FLOWS EXPECTED TO REMAIN ON A GRADUAL DOWNWARD TREND. AFTER COORDINATION WITH THE EMERGENCY MANAGER WENT AHEAD AND CANCELLED THE REMAINING FLOOD ADVISORY FOR THE EAGLE RIVER BELOW GYPSUM. ALTHOUGH WATER LEVELS ARE DECREASING FLOWS REMAIN COLD... SWIFT...AND TURBULENT AND CAUTION IS URGED WHEN AROUND RIVERS AND STREAMS. STAY TUNED TO THE LATEST FORECASTS AND FLOOD INFORMATION AT WEATHER.GOV/GJT && .GJT WATCHES/WARNINGS/ADVISORIES... .CO...NONE. .UT...NONE. $$ UPDATE.........TAL SHORT TERM.....PF LONG TERM......JOE AVIATION.......PF HYDROLOGY......TAL co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIAMI FL 1116 AM EDT THU JUN 26 2008 .UPDATE... HAVE ALREADY UPDATED GRIDS TO REFLECT HIGHER POPS EXPECTED ACROSS THE NORTH-CENTRAL PORTION OF THE FORECAST AREA THIS AFTERNOON... IN THE GENERAL VICINITY OF LAKE OKEECHOBEE. THIS IS THE REGION WHERE STRONGEST LOW-LEVEL CONVERGENCE WILL LIKELY BE FOCUSED... NEAR A WEAK BOUNDARY. ALSO INCLUDED MENTION OF GUSTY WINDS/SMALL HAIL/LOCALLY HEAVY RAINFALL...BASED ON EVENTS FROM PREVIOUS DAYS. OTHERWISE...ADJUSTED WINDS UPWARD OVER THE SOUTHERN ATLANTIC WATERS...BASED ON CURRENT OBSERVATIONS...AND ADDED SCEC HEADLINE TO THESE MARINE ZONES AS WELL AS BISCAYNE BAY. ALL UPDATED PRODUCTS WILL BE ISSUED SHORTLY. 70/DD && .AVIATION DISCUSSION... /ISSUED 731 AM EDT THU JUN 26 2008/ MORNING AVIATION... THE EASTERLY WIND FLOW OF 10 TO 15 KNOTS WILL CONTINUE TODAY ACROSS SOUTH FLORIDA...EXCEPT FOR A WEST COAST SEA BREEZE THAT WILL DEVELOP EARLY THIS AFTERNOON AT AFP TAF SITE. THE EASTERLY WIND FLOW WILL ALLOW FOR ONLY SHOWERS TO AFFECT THE EAST COAST TAF SITES TODAY...AND THUNDERSTORMS AT APF TAF SITE THIS AFTERNOON. SO WILL SHOW VCSH FOR THE EAST COAST TAF SITES...AND VCTS FOR APF TAF SITE BETWEEN 18Z AND 23Z. THE SKIES AND VIS WILL REMAIN IN THE VFR CONDITIONS TODAY FOR THE EAST COAST TAF SITES AND APF TAF SITE. WILL AMEND THE APF TAF SITE AS NEEDED THIS AFTERNOON ONCE THE THUNDERSTORMS HAVE STARTED TO DEVELOP OVER THIS AREA. AVIATION...54/BNB PREV DISCUSSION... /ISSUED 455 AM EDT THU JUN 26 2008/ DISCUSSION... THE LATEST WATER VAPOR IMAGERY...RUC ANALYSIS AND THE RECENT GUIDANCE INDICATE AN UPPER LEVEL RIDGE OVER THE SOUTH FLORIDA PENINSULA. A PLUME OF UPPER LEVEL MOISTURE AND CLOUDINESS CONTINUES TO COME ACROSS THE YUCATAN PENINSULA AND ACROSS THE GULF AND OVER THE SOUTH FLORIDA PENINSULA...WITH A PERSISTENT UPPER LEVEL TROUGH WELL ESTABLISHED OVER THE WESTERN GULF. A TROPICAL WAVE SOUTH OF CUBA IS ALSO INTERACTING WITH THE SOUTHERN EXTENSION OF THE UPPER LEVEL TROUGH AND ALSO CONTRIBUTING TO CONSIDERABLE CLOUDINESS IN THE SOUTHEASTERN GULF. RECENT GUIDANCE INDICATES THAT THE MID LEVELS WILL BE DRY IN THE SHORT TERM...WITH THE AFOREMENTIONED UPPER LEVEL MOISTURE AND ASSOCIATED CIRRUS PERSISTING ACROSS THE REGION FOR AT LEAST THE NEXT SEVERAL DAYS. WITH HIGH PRESSURE DOMINATING THE SOUTH FLORIDA PENINSULA AND LACK OF DEEP LAYERED MOISTURE...ONLY EXPECTING SCATTERED SHOWERS AND THUNDERSTORMS TODAY...WITH THE EAST TO EAST SOUTHEAST LOW TO MID LEVEL WINDS FAVORING THE WESTERN INTERIOR SECTIONS AND THE NAPLES AREA THIS AFTERNOON. THIS TREND SHOULD CONTINUE THROUGH THE WEEKEND. LATEST GUIDANCE SUGGESTS THAT PWATS SHOULD BE AROUND 1.7 INCHES THROUGH THIS PERIOD...SO ISOLATED AREAS OF LOCALLY HEAVY RAINFALL ARE POSSIBLE EACH AFTERNOON THROUGH THE WEEKEND...BUT AGAIN FAVORING THE WESTERN INTERIOR AND MAINLY DURING THE AFTERNOON. MARINE... LATEST GUIDANCE INDICATES THAT EAST TO EAST SOUTHEAST FLOW WILL PERSIST OVER THE LOCAL WATERS THROUGH THE WEEKEND. IN GENERAL THE WINDS OVER THE LOCAL ATLANTIC WATERS EAST OF PALM BEACH COUNTY ARE EXPECTED TO BE IN THE 5 TO 10 KNOT RANGE...WITH 10 TO 15 KNOTS ELSEWHERE OVER THE ATLANTIC WATERS. THE OFF SHORE GULF WATERS WILL BE NEAR 10 KNOTS WITH PERIODS OF 10 TO 15 KNOTS POSSIBLE. FIRE WEATHER... NO FIRE WEATHER CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 91 77 90 77 / 50 30 20 10 FORT LAUDERDALE 90 79 90 80 / 40 20 20 10 MIAMI 91 79 91 78 / 40 20 20 10 NAPLES 91 74 93 75 / 50 20 30 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ LONG TERM...70/DD SHORT TERM/AVIATION...54/BNB fl AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MIAMI FL 731 AM EDT THU JUN 26 2008 .MORNING AVIATION... THE EASTERLY WIND FLOW OF 10 TO 15 KNOTS WILL CONTINUE TODAY ACROSS SOUTH FLORIDA...EXCEPT FOR A WEST COAST SEA BREEZE THAT WILL DEVELOP EARLY THIS AFTERNOON AT AFP TAF SITE. THE EASTERLY WIND FLOW WILL ALLOW FOR ONLY SHOWERS TO AFFECT THE EAST COAST TAF SITES TODAY...AND THUNDERSTORMS AT APF TAF SITE THIS AFTERNOON. SO WILL SHOW VCSH FOR THE EAST COAST TAF SITES...AND VCTS FOR APF TAF SITE BETWEEN 18Z AND 23Z. THE SKIES AND VIS WILL REMAIN IN THE VFR CONDITIONS TODAY FOR THE EAST COAST TAF SITES AND APF TAF SITE. WILL ADMEND THE APF TAF SITE AS NEEDED THIS AFTERNOON ONCE THE THUNDESTORMS HAVE STARTED TO DEVELOP OVER THIS AREA. && .AVIATION...54/BNB .PREV DISCUSSION... /ISSUED 455 AM EDT THU JUN 26 2008/ DISCUSSION... THE LATEST WATER VAPOR IMAGERY...RUC ANALYSIS AND THE RECENT GUIDANCE INDICATE AN UPPER LEVEL RIDGE OVER THE SOUTH FLORIDA PENINSULA. A PLUME OF UPPER LEVEL MOISTURE AND CLOUDINESS CONTINUES TO COME ACROSS THE YUCATAN PENINSULA AND ACROSS THE GULF AND OVER THE SOUTH FLORIDA PENINSULA...WITH A PERSISTENT UPPER LEVEL TROUGH WELL ESTABLISHED OVER THE WESTERN GULF. A TROPICAL WAVE SOUTH OF CUBA IS ALSO INTERACTING WITH THE SOUTHERN EXTENSION OF THE UPPER LEVEL TROUGH AND ALSO CONTRIBUTING TO CONSIDERABLE CLOUDINESS IN THE SOUTHEASTERN GULF. RECENT GUIDANCE INDICATES THAT THE MID LEVELS WILL BE DRY IN THE SHORT TERM...WITH THE AFOREMENTIONED UPPER LEVEL MOISTURE AND ASSOCIATED CIRRUS PERSISTING ACROSS THE REGION FOR AT LEAST THE NEXT SEVERAL DAYS. WITH HIGH PRESSURE DOMINATING THE SOUTH FLORIDA PENINSULA AND LACK OF DEEP LAYERED MOISTURE...ONLY EXPECTING SCATTERED SHOWERS AND THUNDERSTORMS TODAY...WITH THE EAST TO EAST SOUTHEAST LOW TO MID LEVEL WINDS FAVORING THE WESTERN INTERIOR SECTIONS AND THE NAPLES AREA THIS AFTERNOON. THIS TREND SHOULD CONTINUE THROUGH THE WEEKEND. LATEST GUIDANCE SUGGESTS THAT PWATS SHOULD BE AROUND 1.7 INCHES THROUGH THIS PERIOD...SO ISOLATED AREAS OF LOCALLY HEAVY RAINFALL ARE POSSIBLE EACH AFTERNOON THROUGH THE WEEKEND...BUT AGAIN FAVORING THE WESTERN INTERIOR AND MAINLY DURING THE AFTERNOON. MARINE... LATEST GUIDANCE INDICATES THAT EAST TO EAST SOUTHEAST FLOW WILL PERSIST OVER THE LOCAL WATERS THROUGH THE WEEKEND. IN GENERAL THE WINDS OVER THE LOCAL ATLANTIC WATERS EAST OF PALM BEACH COUNTY ARE EXPECTED TO BE IN THE 5 TO 10 KNOT RANGE...WITH 10 TO 15 KNOTS ELSEWHERE OVER THE ATLANTIC WATERS. THE OFF SHORE GULF WATERS WILL BE NEAR 10 KNOTS WITH PERIODS OF 10 TO 15 KNOTS POSSIBLE. FIRE WEATHER... NO FIRE WEATHER CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 90 77 90 77 / 30 20 20 10 FORT LAUDERDALE 89 79 90 80 / 30 20 20 10 MIAMI 90 79 91 78 / 20 20 20 10 NAPLES 91 74 93 75 / 40 20 30 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ LONG TERM...60/BD SHORT TERM/AVIATION...47/RHG fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1041 AM CDT THU JUN 26 2008 .DISCUSSION... ISSUED 1041 AM CDT THU JUN 26 2008 RATHER COMPLICATED SFC PATTERN THIS MORNING WITH SEVERAL MESOSCALE FEATURES ON THE MAP. DECAYING MCS IS MOVING SOUTHWARD ACROSS CENTRAL MISSOURI...WHILE ANOTHER MATURE MCS ROLLS ACROSS CENTRAL IOWA. MEANWHILE...LEFTOVER MCV WAS CENTERED JUST EAST OF KBMI... WITH A BOUNDARY ARCING JUST WEST OF KCMI DOWN TO NEAR KTAZ. WITH WARM/MOIST BOUNDARY LAYER AND MOSTLY SUNNY SKIES AHEAD OF THE MCV AND ATTENDANT BOUNDARY...CANNOT OUTRULE SCATTERED CONVECTION DEVELOPING ACROSS THE FAR EAST AND SOUTHEAST THIS AFTERNOON. MCS OVER IOWA SEEMS LIKELY TO TAKE A DIVE TO THE SOUTH LIKE THE PREVIOUS MCS DID...PERHAPS JUST GRAZING OUR FAR WESTERN COUNTIES THIS AFTERNOON. RUC ANALYSIS INDICATES DISTINCT BUBBLE OF STABLE AIR OVER ILLINOIS...WHILE INSTABILITY AXIS ARCS FROM NORTHWESTERN IOWA INTO SOUTHERN MISSOURI...REMAINING JUST WEST OF THE MISSISSIPPI RIVER. IOWA MCS WILL MOSTLY LIKELY TEND TO DRIFT ESE WITH THE MID-LEVEL FLOW...THEN PROPAGATE SOUTHWARD ALONG THE INSTABILITY AXIS... WHILE DECAYING SHOWERS MAY DRIFT INTO THE WESTERN EDGE OF THE STABLE BUBBLE REGION. RESHAPED THE POP FORECAST CONSIDERING THESE FEATURES. ALSO COOLED TEMPS A FEW DEGREES IN THE WEST CONSIDERING MID/HIGH LEVEL CLOUD COVER FROM CONVECTION TO THE WEST. WILL HAVE NEW ZONES AND FRESH GRIDS OUT AROUND 11 AM. HARDIMAN && .AVIATION... ISSUED 658 AM CDT THU JUN 26 2008 MAIN AVIATION CONCERNS THROUGH THE 12Z TAF PERIOD REVOLVE AROUND SHOWER/STORM CHANCES AND COVERAGE THROUGH THIS EVENING. VFR CONDITIONS WILL PREVAIL OUTSIDE OF ANY PRECIPITATION. A FEW DECAYING STORM COMPLEXES ARE MOVING ACROSS THE MIDWEST AT THE MOMENT AND SHOULD LARGELY DISSIPATE BY LATE MORNING. DO NOT EXPECT THIS PRECIPITATION TO IMPACT THE TERMINALS. OUTFLOW BOUNDARIES LEFT BEHIND BY THESE STORM COMPLEXES MAY SERVE AS A FOCUS FOR ADDITIONAL STORM DEVELOPMENT THIS AFTERNOON AND EVENING. HOW MUCH DEVELOPMENT AND WHERE IT OCCURS IS VERY DEPENDANT ON WHERE THE BOUNDARIES END UP AND HOW MUCH THE SKIES CLEAR AS THE MORNING SYSTEM DISSIPATES. THESE FACTORS MAKE SPECIFIC TIMING AND LOCATION FOR AFTERNOON/EVENING STORMS TOO TOUGH TO CALL AT THIS TIME. HAVE ONLY GONE WITH VCTS IN THE TERMINALS FROM EARLY/MID AFTERNOON INTO EARLY/MID EVENING AT THIS TIME. MORE DETAIL CAN BE ADDED THIS MORNING AS THINGS BECOME MORE CLEAR. INITIALLY VARIABLE WINDS THIS MORNING DUE TO THE CONVECTION WILL PICK UP OUT OF THE SOUTHWEST WITH DIURNAL HEATING TO 12=15 KTS. WINDS WILL DIE OFF SOME AND TURN MORE SOUTHERLY AROUND SUNSET. BAK && .PREV DISCUSSION... ISSUED 330 AM CDT THU JUN 26 2008 MODELS HAVE NOT BEEN HANDLING MCS/MCV ACTIVITY VERY WELL DURING THE PAST FEW NIGHTS...SO CONFIDENCE IN FORECAST WHICH MAKES THIS FORECAST TRICKIER THAN NORMAL. CURRENT MCS/MCV OVER NE MO/SE IA AND INTO CENTRAL IL WAS NOT DEPICTED BY MODELS. FORECAST CONCERN IS CONVECTION CHANCES AND SLIGHT RISK OF SEVERE STORMS THROUGH SAT. RADAR MOSAIC AND SATELLITE SHOWS A MCS/MCV OVER NE MO/SE IA AND INTO CENTRAL IL WITH LEADING EDGE OF CONVECTION ALONG I-55 WITH A THUNDERSTORM AS FAR EAST AS NORTHERN FORD COUNTY AND MOVING ESE. SEVERE WX THREAT APPEARS TO HAVE DIMINISHED OVER CENTRAL IL WHILE STRONGER LINE OF STORMS WAS PLOWING SOUTH TOWARD I-70 IN CENTRAL MO. STILL GETTING SOME THUNDERSTORMS WITH HEAVY RAINS ALONG THE IL RIVER AND JUST NORTH OF SPRINGFIELD. 08Z/3 AM SURFACE MAP SHOWS 1007 MB LOW PRESSURE OVER EASTERN LAKE SUPERIOR WITH A FRONTAL BOUNDARY EXTENDING THROUGH CENTRAL WI...NORTHERN IA AND CENTRAL NEBRASKA. MUGGY DEWPOINTS IN THE MID TO UPPER 60S WHILE TEMPS WERE IN THE LOW TO MID 70S. ALOFT A LARGE UPPER LEVEL HIGH PRESSURE RIDGE WAS SPRAWLED ACROSS THE SOUTHERN STATES WHILE UPPER LEVEL LOW/TROF OVER CANADA. SHORT WAVE TROF WAS OVER NW IL INTO MO WHERE MCS/MCV WAS. ANOTHER ONE WAS OVER OHIO AND YET ANOTHER OVER THE DAKOTAS. SHORT TERM...TODAY THROUGH SATURDAY. CONVECTION FROM MCS TO WEAKEN DURING THIS MORNING OVER CENTRAL IL LIKE IT DID YESTERDAY MORNING. BUT MCV FROM THIS MCS WILL DRIFT INTO EASTERN/NE IL AND INDIANA AND WILL DEVELOP SCATTERED CONVECTION THIS AFTERNOON IN UNSTABLE AIR MASS SO KEPT 30 TO 40% CHANCE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON. HIGHS TODAY IN THE UPPER 80S TO AROUND 90F WITH LOWER 90S IN SE IL WHERE MORE SUNSHINE EXPECTED LIKE YESTERDAY. HUMID WITH DEWPOINTS IN THE UPPER 60S AND LOWER 70S. ANOTHER MCS TO DEVELOP TONIGHT OVER IA/NORTHERN IL AND MOVE ESE AND GOOD CHANCE IT WILL AFFECT AREAS ALONG AND NORTH OF I-74. SPC HAS SLIGHT RISK OF SEVERE STORMS NORTH OF A SPRINGFIELD TO PARIS LINE TONIGHT. HEAVY RAINS AND FREQUENT LIGHTNING FROM THUNDERSTORMS AS WELL. CONVECTION CHANCES INCREASE AGAIN FRI AFTERNOON ESPECIALLY NW OF I-55 AS UPPER LEVEL TROF AMPLIFIES/DIGS INTO THE MIDWEST AND DRIVES A COLD FRONT SE INTO NW IL BY MIDNIGHT FRI NIGHT. HIGHS AGAIN IN THE UPPER 80S WITH LOWER 90S SE IL AND HUMID WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S. LIKELY CHANCE OF CONVECTION FRI NIGHT NW OF I-70. SPC HAS IL IN SLIGHT RISK FRI NIGHT WHILE GREAT RISK OF SEVERE STORMS OVER CENTRAL/NW IL ALONG AND NW OF A DANVILLE TO TAYLORVILLE LINE. HAVE FRONT COLLIDING WITH A VERY UNSTABLE AIR MASS WITH CAPES PEAKING FROM 2000 TO 4000 J/KG. COULD BE WIDESPREAD SEVERE HAIL/WINDS FRI NIGHT ESPECIALLY FRI EVENING WITH TORNADO THREAT MORE OVER NORTHERN IL WHERE MORE FAVORABLE STRONGER WIND FIELDS. COLD FRONT SLIDES SE THROUGH CENTRAL IL AFTER MIDNIGHT FRI NIGHT AND THRU SE IL SAT. BEST CHANCES OF CONVECTION SHIFT INTO EASTERN/SE IL SAT WHERE SPC HAS SLIGHT RISK OF SEVERE. SHOWERS TO END OVER THE IL RIVER VALLEY SAT AFTERNOON. A BIT COOLER HIGHS IN THE LOW TO MID 80S BUT RATHER HUMID YET WITH DEWPOINTS IN THE 60S. LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY. EXTENDED MODELS SHOW UPPER LEVEL LOW SETTLING INTO THE GREAT LAKES THIS WEEKEND AND OVER NORTHERN LOWER MI SUNDAY. IT NOW APPEARS CLOSE ENOUGH TO CENTRAL IL TO PRODUCE ISOLATED SHOWERS AND THUNDERSTORMS SUNDAY AFTERNOON. UPPER LEVEL LOW TRACKS SLOWLY EAST MON/TUE WITH DRY WX EXPECTED OVER CENTRAL/SE IL AND LESS HUMID AIR MASS. COOLED HIGHS A BIT THOUGH NOT QUITE AS COOL AS MEX/ECMWF HIGHS IN THE 70S SUN/MON. TEMPS WILL GRADUALLY MODIFY TUE/WED AS UPPER LEVEL LOW PULLS FURTHER AWAY FROM THE GREAT LAKES. HUETTL && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 632 AM CDT THU JUN 26 2008 .AVIATION... FOR 12Z TAFS...VERY LITTLE IN THE WAY OF AVIATION CONCERNS TODAY WITH VFR CONDITIONS EXPECTED ALL DAY. SURFACE LOW PRESSURE WILL STRENGTHEN OVER THE HIGH PLAINS TODAY ALLOWING SOUTH WINDS TO BE A BIT STRONGER THAN THE LAST FEW DAYS. MOST SITES(WITH THE EXCEPTION OF KCNU) CAN EXPECT SOUTH WINDS AT 20 MPH WITH GUSTS TO 30 MPH. THE BULK OF THE STORMS TODAY AND TONIGHT WILL REMAIN NORTH OF KANSAS ALONG A COLD FRONT. LAWSON && .PREV DISCUSSION... /ISSUED 316 AM CDT THU JUN 26 2008/ DISCUSSION... FORECAST CONCERNS...CONVECTIVE CHANCES/TRENDS AND SEVERE POTENTIAL FRIDAY AFTERNOON THROUGH FRIDAY NIGHT. ONLY SUBTLE CHANGES IN SENSIBLE WEATHER EXPECTED FOR TODAY...SO WILL FOLLOW A MODIFIED PERSISTENCE APPROACH TO THE FORECAST AND MOST GRID ELEMENTS TODAY. A BIT MORE OF A CAP EARLY THIS MORNING BASED ON RUC MODEL...SO HOPEFULLY WILL NOT SEE ANOTHER SUNRISE SURPRISE TOWARD DAWN...ISOLATED AS IT WAS YESTERDAY. OTHERWISE EXPECT A COUPLE LOCALES TO APPROACH/TOUCH THE CENTURY MARK ACROSS CENTRAL KANSAS THIS AFTERNOON. DESPITE MAXS IN THE LOW/MID 90S FOR THE REST OF THE AREA...IT WILL FEEL CLOSE TO 100 WITH COMBO OF HEAT AND HUMIDITY. CONVECTION THAT DEVELOPS NORTHWEST OF THE AREA THIS EVENING MAY CLIP NORTHERN PORTIONS OF THE FORECAST AREA TONIGHT...SO WILL KEEP A SLIGHT CHANCE IN FOR THOSE AREAS. HOWEVER...MAIN FOCUS FOR MORE ORGANIZED CONVECTION WILL COME LATER FRIDAY INTO EARLY SATURDAY MORNING...AS A STRONG SUMMER-TIME UPPER TROF AND THE ASSOCIATED COLD FRONT DROPS SOUTHEAST ACROSS THE MIDWEST. THIS TROF WILL DEEPEN ACROSS THE GREAT LAKES WITH A REINFORCING SHOT OF COOLISH/DRIER AIR SATURDAY NIGHT INTO SUNDAY. THE FRONT ON FRIDAY EVENING LOOKS TO ENCOUNTER A VERY UNSTABLE AIRMASS ACROSS EASTERN KANSAS...AND CONFIDENCE CONTINUES BUILD ON A SEVERE CONVECTIVE EPISODE...SO HAVE UPPED POPS INTO THE LIKELY CATEGORY FOR AREAS EAST OF THE KANSAS TURNPIKE FRIDAY NIGHT. STILL SOME QUESTION AS TO THE TIMING/SOUTHWARD MOVE OF THE FRONT...WITH THE NAM MORE PROGRESSIVE THAN OTHER MODELS. THIS MAY HAVE MORE OF AN IMPACT ON MAXS FOR CENTRAL KANSAS ON FRIDAY...AND FOR NOW WILL STILL KEEP THINGS QUITE TOASTY...HOWEVER AREAS OF SOUTH CENTRAL LOOK TO BE THE HOTTEST...ESPECIALLY FOR AREAS WEST AND SOUTHWEST OF GREATER WICHITA WHERE PERHAPS A DRIER SOUTHWEST FLOW AND SOME COMPRESSIONAL WARMING EFFECTS WILL ENHANCE MAX POTENTIAL LATE IN THE AFTERNOON. OTHERWISE...HAVE TEMPERED MAXS FOR THE WEEKEND...ESPECIALLY FOR SUNDAY...WITH MODEL CONSENSUS SUGGESTING RELATIVELY COOLER AIR WILL HOLD SWAY THRU THE WEEKEND NOW. DARMOFAL AVIATION... 06Z TAFS...ICT/SLN/HUT/CNU/RSL...VFR CONDITIONS ANTICIPATED OVER THE NEXT 24 HOURS. STRENGTHENING AND VEERING LOW-LEVEL JET TONIGHT MAY INITIATE A STRAY THUNDERSTORM SOMEWHERE ACROSS CENTRAL AND SOUTHEAST KANSAS TONIGHT...BUT PREDICTABILITY IS TOO LOW AND COVERAGE TOO SPARSE TO MENTION VCTS IN THE TAFS. OTHERWISE...STOUT SOUTHERLY WINDS WILL COMMENCE BY MID-MORNING THURSDAY...AS LOW PRESSURE STRENGTHENS ACROSS THE WESTERN HIGH PLAINS...AND A COLD FRONT GETS ITS ACT TOGETHER NORTHWEST OF THE AREA. KLEINSASSER && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 95 73 97 71 / 10 10 20 50 HUTCHINSON 96 72 98 69 / 10 10 30 50 NEWTON 95 73 97 70 / 10 10 30 50 ELDORADO 94 73 95 71 / 10 10 20 60 WINFIELD-KWLD 94 73 96 72 / 10 10 20 60 RUSSELL 100 71 95 66 / 10 20 40 20 GREAT BEND 99 71 97 67 / 10 10 40 30 SALINA 99 73 97 68 / 10 20 40 40 MCPHERSON 97 73 97 69 / 10 10 40 40 COFFEYVILLE 92 72 93 72 / 10 10 20 60 CHANUTE 92 72 93 72 / 10 20 20 60 IOLA 92 72 93 72 / 10 20 20 60 PARSONS-KPPF 92 72 93 72 / 10 10 20 60 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ks AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON KY 1043 AM EDT THU JUN 26 2008 .SHORT TERM.../THE REST OF TODAY/...UPDATED THE MAIN FOCUS FOR THE UPDATE THIS MORNING WILL DEAL WITH THE THREAT FOR AFTERNOON THUNDERSTORMS. THE MAIN CHANGE TO POPS WAS TO ADD A FEW MORE COUNTIES A LITTLE FURTHER SOUTH IN THE CHANCE POP RANGE. CURRENT WATER VAPOR IMAGERY/RUC 13 SHOW THE POTENTIAL FOR AN APPROACHING WEAK SHORT WAVE TO INFLUENCE COUNTIES MAINLY NORTH OF INTERSTATE 64. THE FEELING IS THAT SCATTERED COVERAGE WOULD REPRESENT THE AREA INFLUENCED BY THE WAVE AND ISOLATED COVERAGE WOULD REPRESENT THE AREAS FURTHER SOUTH WHO NEED TO REACH THEIR CONVECTIVE TEMPS. LAPS AND FORECAST SOUNDINGS SHOW A WEAK WIND PROFILE THROUGH THE ENTIRE COLUMN...SO ANY ORGANIZED THUNDERSTORMS WOULD BE VERY HARD TO COME BY. THE BEST CHANCE FOR ANY ORGANIZATION WOULD BE IN THE NORTH WHERE BETTER FORCING FOR ASCENT WILL BE ASSOCIATED WITH THE WEAK SHORTWAVE. CURRENT SURFACE OBS SHOW 14Z TEMPERATURES WELL ON THEIR WAY TO THE UPPER 80S TO AROUND 90 DEGREES. DID NOT CHANGE MUCH IN THE WAY OF TEMPERATURES...ONLY MADE A FEW MINOR TWEAKS BASED ON CURRENT TRENDS. EXPECT MOISTURE TO CONTINUE TO INCREASE TODAY...SETTING UP THE APPROACHING WEEKEND SYSTEM. UPDATED ZFP OUT SHORTLY. THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS... /TODAY THROUGH FRIDAY NIGHT/ MOISTURE RETURN WILL GRADUALLY INCREASE ACROSS EASTERN KENTUCKY TODAY AS UPPER RIDGE WEAKENS AND MOVES OFF TO THE EAST AND SOUTHEAST. FLOW PATTERN WILL TRANSITION TO MORE ZONAL...LEAVING US OPEN TO MORE EMBEDDED WEAK SHORT WAVES. HAVE MAINTAINED ISOLATED POPS FOR ALL TODAY WITH CONVECTIVE TEMPERATURES LIKELY BEING REACHED FOR SOME. BETTER CHANCE WILL EXIST IN THE BLUEGRASS COUNTIES CLOSER TO THE TRAIN OF TRAVERSING WEAK DISTURBANCES ALONG WITH AMPLE MOISTURE RETURN...SO HAVE GONE WITH SCATTERED CONVECTION IN THE AFTERNOON. STUCK CLOSER TO THE NAM MOS FOR HIGHS AT JKL...WHILE USING THE GFS MOS FOR LOZ AND SME. SCATTERED CONVECTION WILL RE-FIRE FRIDAY AFTERNOON INTO FRIDAY EVENING AS WE BECOME MORE UNDER THE INFLUENCE OF TROUGHING TAKING PLACE ACROSS THE NORTHERN PLAINS WITH ADDITIONAL WEAK DISTURBANCES MOVING TOWARDS THE AREA. INCREASED CLOUD COVER WILL KEEP HIGHS A BIT COOLER ON FRIDAY...HOWEVER CONTINUED MOISTURE ADVECTION WILL KEEP THE AIR MASS VERY MUGGY. USED A BLEND OF PERSISTENCE AND THE LATEST GUIDANCE FOR TEMPERATURES FROM TONIGHT THROUGH FRIDAY NIGHT. .LONG TERM.../SATURDAY THROUGH WEDNESDAY/ THE MAIN FOCUS FOR THE LONG TERM FORECAST PERIOD WILL DEAL THE APPROACH AND ARRIVAL OF A COLD FRONT ASSOCIATED WITH AN UNSEASONABLY STRONG UPPER LEVEL LOW TO THE NORTHWEST. HAVE DECIDED TO BLEND BETWEEN THE GFS/ECMWF SOLUTIONS AS SLOWER AND MORE SOUTHERLY TRACK SEEMS TO BE THE WAY TO GO. THE LATEST HPC DISCUSSIONS SEEMS TO AGREE WITH THIS DECISION AS WELL. AS A RESULT...HAVE SLOWED THE SYSTEM DOWN WHICH WILL GIVE US PRETTY GOOD CHANCES FOR RAIN...POSSIBLY HEAVY AT TIMES...STARTING SATURDAY AND ENDING SUNDAY AFTERNOON. AN INTERESTING SETUP WITH SURFACE HIGH PRESSURE OFF THE SOUTHEAST COAST SHOULD PROVIDE PLENTY OF MOISTURE RETURN AHEAD OF THE SYSTEM ON SATURDAY. UPLIFT FROM MULTIPLE WAVES EMBEDDED IN THE HIGHLY AMPLIFIED H5 TROUGH WILL ALLOW FOR CONTINUING CHANCES OF PRECIPITATION. HAVE SLIGHTLY INCREASED POPS TO GOOD CHANCE AND LIKELY FOR MOST OF THE EVENT. LATEST GUIDANCE VALUES ALSO CAME IN WITH HIGHER POPS ADDING CONFIDENCE TO THE FORECAST. BASED ON NAM/GFS FORECAST SOUNDINGS...SOME CONCERN IS STARTING TO GROW WITH REGARD TO HEAVY RAINFALL POSSIBLE LATE SATURDAY AFTERNOON AND NIGHT. VERY MOIST/TROPICAL LIKE SOUNDINGS SHOW TALL SKINNY CAPE PROFILES AND PWAT VALUES AROUND 2 INCHES ON SATURDAY. SOUTHWEST TO NORTHEAST LINEAR FORCING ASSOCIATED WITH THE FRONT AND FAIRLY SLOW STORM MOTIONS PARALLEL TO THIS COULD RESULT IN TRAINING OF VERY EFFICIENT THUNDERSTORMS. WILL HAVE TO MONITOR THIS SITUATION CLOSELY AND KEEP THE NAM MOISTURE BIAS IN MIND. HAVE DECIDED TO MENTION THE POSSIBILITY OF THE THREAT FOR LOCALLY HEAVY RAINFALL IN THE HWO. THE COLD FRONT FINALLY MOVES THROUGH SOMETIME ON SUNDAY WITH POPS ENDING LATE SUNDAY AFTERNOON. HAVE KEPT THE REST OF THE EXTENDED DRY FOR NOW...HOWEVER LINGERING MOISTURE AND ANY WAVES EMBEDDED IN THE RETREATING H5 TROUGH COULD ALLOW FOR SOME VERY ISOLATED COVERAGE. TOO MUCH UNCERTAINTY EXISTS AT THIS POINT TO INCLUDE SLIGHT CHANCE POPS. AS FAR AS TEMPERATURES GO...DID NOT MAKE MANY CHANGES. ONLY MADE A FEW MINOR ADJUSTMENTS BASED ON LATEST GUIDANCE VALUES. && .AVIATION.../12Z TO 12Z/ WEAK UPPER RIDGE WILL WORK TO KEEP CONVECTION TO A MINIMUM OVER EAST KENTUCKY AGAIN TODAY. HOWEVER...CANNOT RULE OUT A STRAY SHOWER OR THUNDERSTORM...ACCORDINGLY KEPT THE MODERATELY HIGH BASED CB SCT GROUP IN THE TAFS FROM EARLY AFTERNOON INTO THE EVENING. OTHERWISE... HIGH CIRRUS CLOUDS WILL DRIFT THROUGH THE AREA. SIMILAR TO WEDNESDAY WINDS WILL BE LIGHT THROUGH THE PERIOD GENERALLY FROM THE SOUTHWEST. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...GEOGERIAN/SCHOETTMER LONG TERM....SCHOETTMER AVIATION...GREIF ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1115 AM EDT THU JUN 26 2008 .UPDATE... DUE TO LAST NIGHTS RAIN/LIGHT WINDS/50S DEWPOINTS...WIDESPREAD FOG DEVELOPED OVER LAKE SUPERIOR AND ADJACENT AREAS OF NORTHERN UPR MI LATE LAST NIGHT. NW/N WINDS OVR LK SUPERIOR AND IN AREAS EAST OF KEWEENAW PENINSULA TO WHITEFISH POINT WILL KEEP SOME FOG AND LOW CLOUDS INTO EARLY AFTN...AT LEAST ALONG THE IMMEDIATE SHORE. FOG OVR KEWEENAW IS ALREADY LIFTING...DUE TO WEAK ADVECTION OF DRY AIR HANGING OUT OVR WESTERN LAKE SUPERIOR. ONSHORE FLOW/CLOUDS/FOG SHOULD KEEP TEMPS IN THE UPR 50S TO UPR 60S ALONG LAKE SUPERIOR SHORE EAST OF THE KEWEENAW PENINSULA. MAINLY SUNNY SKIES INLAND AND STILL WARM H85/H8 TEMPS LEAD TO MAX TEMPS REACHING WELL INTO THE 80S OVR SCNTRL SECTIONS AWAY FM BAY OF GREEN BAY. MODIFIED GRB SOUNDING FOR T/TD OF 85/63 AND THAT DID GIVE SBCAPE AOA 1000 J/KG. HOWEVER ...DRY MID LEVEL AIR IS EVIDENT AS IS SOME CAPPING AROUND 750MB AND LARGE SCALE FORCING FOR ANY SHOWERS IS NIL. ABOUT THE ONLY TRIGGER WOULD BE LAKE BREEZE FRONT OFF LAKE MICHIGAN...BUT THAT WOULD APPEAR TO BE PRETTY SHALLOW AND NOT SUFFICIENT TO KICK OFF ANY CONVECTION. && .DISCUSSION (530 AM EDT)... MAIN CONCERNS FOCUS ON TIMING OF CONVECTION ON FRIDAY AND POSSIBLE SVR STORMS...THEN LINGERING SHRA/TSRA INTO THE WEEKEND. WATER VAPOR LOOP AND RUC ANALYSIS CONTINUE TO SHOW ZONAL FLOW ACROSS THE NRN CONUS. SHORTWAVE RESPONSIBLE FOR LAST NIGHT`S CONVECTION HAS MOVED EAST OF THE AREA. IR SATELLITE NOW SHOWS CLEARING SKIES FROM THE WEST AS MID LVL RDGG AND SUBSIDENCE NOSE INTO THE AREA. HOWEVER...DEWPOINTS REMAIN FAIRLY HIGH (UPR 50S TO LOW 60S) AND FOG LINGERS OVER MUCH OF LAKE SUPERIOR EARLY THIS MORNING AND OVER THE SHORELINE AREAS. TODAY...EXPECT AREAS OF FOG NEAR THE LAKE SUPERIOR SHORELINE TO LIFT AFTER SUNRISE WITH SUNNY SKIES PREVAILING UNDER MID-LVL RIDGING AND SUBSIDENCE. 800 MB TEMPS NEAR 12C MIXING TO THE SFC SHOULD YIELD HIGHS IN THE LOWER 80S OVER THE WRN INTERIOR. LAKE BREEZES DEVELOPING WILL KEEP TEMPS COOLER (LOWER 70S) NEAR THE GREAT LAKES AND OVER THE ERN FCST AREA. TONIGHT...EXPECT DRY CONDITIONS TO CONTINUE UNDER THE INFLUENCE OF THE SFC HIGH ALTHOUGH THERE WILL BE SOME INCREASE IN WAA MID-HIGH LVL CLOUDS FROM THE SW LATE AHEAD OF NEXT INCOMING SHORTWAVE. EXPECT LOWS TO GENERALLY BE IN THE MID 50S WITH SLIGHTLY COOLER READINGS EAST WHERE SKIES SHOULD BE CLEAR MOST OF THE NIGHT. FRIDAY...GENERALLY FOLLOWED A BLEND OF THE NAM/UKMET/ECMWF AND SREF MODELS AS THE GFS AND EVEN THE GLOBAL GEM LOOK TO BE AFFECTED BY CONVECTIVE FEEDBACK. ALL THESE MODELS BRING THE LEAD SHORTWAVE INTO THE AREA ON FRI AHEAD OF AN UPR TROF/CLOSED LOW DEVELOPING OVER THE NRN PLAINS. 305K ISENTROPIC ASCENT ASSOC WITH THIS SHORTWAVE WILL SUPPORT THE INITIAL BATCH OF CONVECTION SPREADING SW TO NE ACROSS THE FCST AREA...MAINLY LATE FRI. BUMPED UP POPS TO LIKELY ACROSS WEST AND CENTRAL PORTIONS SINCE MODELS HAVE COME INTO BETTER AGREEMENT ON TIMING/COVERAGE OF SHRA/TSRA. STRONG MOISTURE INFLOW WITH PWAT INCREASING TO AOA 1.5 INCHES COULD SUPPORT HEAVY DOWNPOURS WITH THE SHOWERS. MUCAPE VALUES INTO THE 1000-1500 J/KG RANGE AND 0-6KM BULK SHEAR INTO THE 30-40 KT RANGE WILL BE ENOUGH TO SUPPORT SOME STRONGER STORMS. HOWEVER...HIGH FREEZING LEVELS (13-14 KFT) SHOULD LIMIT LARGE HAIL THREAT. SPC STILL HAS THE ENTIRE U.P IN A SLIGHT RISK OF SVR FOR THE DAY2 CONVECTIVE OUTLOOK. FRI NIGHT...AS THE MID/UPPER LEVEL LOW SINKS SLOWLY ESE TOWARD THE UPPER GREAT LAKES...A DRY SLOT WILL SPREAD THROUGH THE AREA REDUCING PCPN CHANCES. FOLLOWED THE PREFERRED SLOWER TIMING OF THE ECMWF AND SREF WITH THIS FEATURE SO KEPT IN SHRA/TSRA CHANCES WITH THE HIGHEST POPS OVER THE EASTERN FCST AREA. SAT INTO SUN...FOLLOWED THE NCEP PREFERRED GFS ENSEMBLE MEAN SOLN WITH MVMT OF THE UPR LOW WHICH IS SIMILAR TO THE OPERATIONAL 00Z ECMWF RUN. FCST 500 MB TEMPS OF -17C/-18C WITH STEEP LOW-MID LEVEL LAPSE RATES AND FORCING FROM SHORTWAVES ROTATING AROUND THE LOW WILL SUPPORT SCT SHRA/TSRA THROUGH THE PERIOD. BY SUN...WITH NRLY LOW LEVEL FLOW DEVELOPING...MUCH COOLER WEATHER IS EXPECTED ESPECIALLY ALONG LAKE SUPERIOR. THERE WILL BE CONTINUED CHCS FOR LIGHT RAIN OR SHOWERS BUT TSTM SHOULD CHANCES SHOULD BE DWINDLING. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... IR SATELLITE IMAGERY AND WEB CAMS INDICATED FAIRLY EXTENSIVE FOG OVER WRN LAKE SUPERIOR EXTENDING INTO THE KEWEENAW PENINSULA. UPSLOPING WEST NORTHWEST WINDS WILL KEEP LIFR CONDITIONS IN FOG/STRATUS APPEAR LIKELY THERE UNTIL AROUND 15Z...WHEN CONDITIONS SHOULD IMPROVE TO VFR. VFR CONDITIONS WILL THEN PREVAIL FOR THE REST OF THE FCST PERIOD. AT KSAW...VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... AS HIGH PRESSURE CROSSES LAKE SUPERIOR TODAY THROUGH FRIDAY MORNING WINDS WILL LESS THAN 20 KNOTS. ANOTHER LOW PRESSURE TROUGH WILL MOVE FROM THE NORTHERN PLAINS TONIGHT AND INTO LAKE SUPERIOR ON FRIDAY NIGHT AND REMAIN THROUGH SATURDAY. PRESSURE GRADIENTS WILL TIGHTEN FOLLOWING THE LOW CAUSING WIND TO INCREASE TO 20 TO 25 KNOTS FOR A PERIOD OVER CENTRAL AND EAST EASTERN LAKE SUPERIOR. BY SUNDAY...THE LOW FILLING SLIGHTLY AND SLIDE SOUTHEASTWARD OVER LOWER MICHIGAN BY SUNDAY MORNING WILL CAUSE THE WINDS TO LESS AN 20 KNOTS FOR THE REMAINDER OF THE PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...JLA DISCUSSION...VOSS AVIATION...ROLFSON/DLG MARINE...KF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 1042 AM CDT THU JUN 26 2008 .UPDATE... LATEST SURFACE ANALYSIS SHOWS A WEAK RIDGE OF HIGH PRESSURE CENTERED NEAR THE BRAINERD LAKES AREA. HIGH CLOUDS CONTINUE TO INCREASE ACROSS THE REGION...ESPECIALLY IN THE SOUTH AND WEST...MAINLY CIRRUS DEBRIS FROM CONVECTIVE COMPLEXES THAT WILL REMAIN WELL SOUTH OF OUR AREA THROUGH THE AFTERNOON. STILL...EXPECTING HIGH CLOUDS TO CONTINUE STREAMING ACROSS THE AREA...FROM SOUTH TO NORTH...THROUGH THE DAY...AND HAVE BUMPED UP SKY COVER ACCORDINGLY. ALSO RAISED AFTERNOON MAX TEMPS SLIGHTLY BASED ON CURRENT TRENDS...MAINLY JUST 1-2 DEGREES...PERHAPS A TAD MORE ALONG THE NORTH SHORE. SILVER BAY HAD ALREADY REACHED 79 AT 15Z...BUT A LAKE BREEZE SHOULD DEVELOP WITHIN THE NEXT FEW HOURS. LATEST RUC AND NAM GUIDANCE PROPAGATES A MID LEVEL SHORTWAVE CURRENTLY OVER EASTERN NORTH DAKOTA/WESTERN MINNESOTA INTO THE BORDERLAND THIS AFTERNOON. WHILE MID-HIGH CLOUDS WILL LIKELY INCREASE WITH THIS FEATURE...NOT EXPECTING MORE THAN ISOLATED SHOWERS OR THUNDERSTORMS...AS THIS FEATURE WILL BE RUNNING INTO INCREASINGLY DRY AIR AND RATHER MARGINAL INSTABILITY. DID BRING SILENT POPS A BIT FURTHER EAST. && .PREV DISCUSSION... /ISSUED 345 AM CDT THU JUN 26 2008/ DISCUSSION... RUC13 ANALYSIS EARLY THIS MORNING INDICATES TEMPORARY RIDGING IN MID LVLS WITH ASSOCIATED DEEPENING OF NWRLY FLOW. ALTHOUGH SFC FLOW HAS DECOUPLED...WSRVWPDLH SHOWS AVERAGE 320/20KT FLOW FROM 2K TO 5K FT. TOUGH CALL ON EARLY MORNING FOG AS POTENTIAL TURBULENT KINETIC ENERGY FROM STRONGER WINDS JUST ABOVE GROUND LVL MAY GENERATE JUST ENOUGH MIXING TO KEEP WIDESPREAD FOG FORMATION. WITH SFC T/TD SPREADS ALREADY LESS THAN 2 DEGREES IN MOST OF NORTHEAST MN...WILL MENTION AREAS OF FOG. HOWEVER...CONFIDENCE NOT VERY HIGH. TODAY...LARGE MASS OF DEBRIS CLOUDS HEADING TOWARDS WRN CWA THIS MORNING FROM NEBRASKA CONVECTION. 85/30H THICKNESS PATTERN SUGGESTS THIS CONVECTION WILL TRANSLATE EASTWARD THIS MORNING...OUTRUNNING THE LLJ AND MSTR TRANSPORT MAXIMUM FARTHER WEST. OTHERWISE...FAIRLY QUIET DAY AS LL WINDS EVENTUALLY SHIFT INTO SOUTHEAST ACROSS MN ZONES AND HUMIDITY INCREASES ONCE AGAIN. CONSENSUS OF MDLS IS THAT AREA WILL REMAIN QPF FREE TODAY. SIM WRF REFLECTIVITY PRODUCT DOES GENERATE CONVECTION LATE TODAY NEAR KOOCH COUNTY HOWEVER IT DOES NOT SEEM TO HAVE INITIAL SITUATION HANDLED VERY WELL. EXPECT WARM TEMPS TODAY ALTHOUGH NOT QUITE AS WARM AS YESTERDAY AS LL THICKNESS/85H TEMPS HAVE DROPPED SEVERAL DEGREES. TONIGHT/FRIDAY...MODELS GENERALLY AGREE ON MAIN SYNOPTIC FEATURES/MASS FIELDS. SIGNIFICANT PROBLEMS ARISE WITH MULTIPLE CONVECTIVE FEEDBACK ISSUES ON GFS..AND PERHAPS EC AS WELL. WILL USE A MORE AVERAGE APPROACH AS DEPICTED BY LATEST SREF/UKM. THIS BRINGS A DEEPENING ELONGATED SFC LOW PRESSURE INTO THE WRN CWA BY EARLY FRIDAY MORNING. SFC PATTERN IS COMPLICATED BY POTENTIAL PHASING OF TWO SEPARATE SHORTWAVES...ONE DROPPING SOUTHEAST FROM MANITOBA AND ONE EJECTING FROM PLAINS. LOOKS LIKE AN OCCLUDED FRONT WILL SWEEP ACROSS THE REGION FRIDAY WITH TRIPLE POINT NEAR TWIN PORTS BY MIDDAY...REDEVELOPING TOWARDS NWRN WISC BY FRIDAY AFTERNOON.SPC HAS SLIGHT RISK OF SVR OVER SWRN CRNR OF CWA...EXTENDING TO SRN BURNETT CO. BY 12Z FRI. DURING THE DAY FRIDAY...ENTIRE CWA IS UNDER SLIGHT RISK. IT APPEARS MOST LIKELY AREA FOR THREAT WILL BE SOUTH OF TWIN PORTS AND INTO WISCONSIN FRIDAY AFTERNOON. THIS IS WHERE SREF IS INDICATING HIGHER PROBABILITY OF SBCAPE. EXTENDED...AS ADVERTISED WITH GOOD CONSISTENCY AMONG MDL SUITE...ANOMALOUS MID LVL LOW WILL SWEEP INTO REGION FOR THE WEEKEND. EXPECT SIGNIFICANT DROP IN TEMPS AND LIKELIHOOD OF SHOWERS/TRW WITH STEEPENING LAPSE RATES SATURDAY. SUNDAY SHOULD BRING SOME DECREASE IN DEEP LAYER MOISTURE WITH DECREASING CHANCE OF POPS. MONDAY/TUESDAY SHOULD BE PLEASANT WITH SUNSHINE RETURNING AND TEMPS REBOUNDING INTO 80S BY TUESDAY. AVIATION... AFTER SOME PATCHY EARLY MORNING FOG...HIGH PRESSURE WILL PROVIDE VFR CONDITIONS TODAY INTO THIS EVENING. AN AREA OF LOW PRESSURE AND A WARM FRONT WILL MOVE NORTH INTO SOUTHERN MINNESOTA AND WISCONSIN OVERNIGHT. THUNDERSTORMS WILL DEVELOP ALONG AND NORTH OF THE FRONT...AND MVFR CONDITIONS WILL DEVELOP...MAINLY AROUND KBRD EAST TOWARD KHYR. WINDS OFF OF LAKE SUPERIOR MAY CAUSE MARINE BASED MVFR OR IFR CEILINGS AND SOME FOG LATE THURSDAY NIGHT...AND THAT WILL AFFECT KDLH/KASX AND POSSIBLY INTO KHIB. && POINT TEMPS/POPS... DLH 81 56 69 51 / 10 30 60 40 INL 82 52 74 55 / 10 30 60 50 BRD 83 60 75 55 / 10 70 60 30 HYR 84 56 74 55 / 10 50 60 40 ASX 80 56 73 53 / 10 20 60 40 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ BETTWY mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1024 AM EDT THU JUN 26 2008 .SYNOPSIS... A STORM SYSTEM MOVING ACROSS LOWER CANADA, WILL DRAG A WEAK COLD FRONT ACROSS NY AND PA THIS AFTERNOON. THIS FRONT WILL CAUSE SCATTERED THUNDERSTORMS TO FORM, WITH A FEW STRONG STORMS POSSIBLE. && .NEAR TERM /THROUGH TONIGHT/... UPDATED AT 1015 AM...-SHRA ASSCD WITH MCV PULLING OUT...AND FOCUS TURNS TO POTNL REDVLPMNT THIS AFTN. RUC PROFILES SHOW THE DVLPMNT OF A MID LVL CAPPING LAYER...A FEATURE WHICH IS EVIDENT IN THE UPSTREAM DTX AND APX SNDGS AND TAMDAR DATA. K INDICES FALL INTO THE M20S ACRS CNTRL NY THIS AFTN...NOT FVRBL FOR REDVLPMNT. XTNSV CLD CVR ACRS THE RGN...WITH EXTRAPOLATION OF BACKEDGE INTO THE FINGER LAKES AND CNTRL SRN TIER IN THE 19-22Z TIME FRAME...WHICH IS IN GOOD AGREEMENT WITH LAMP DATA. BEST POTNL MAY ACTUALLY BE THIS EVENING IN THE 00Z-06Z TIME FRAME...AS INFLUENCES FROM WEAK S/WV AND SFC TROF BEGIN TO ENCROACH ON NW ZONES...WHERE GREATEST INSTAB SHUD RESIDE DUE TO MORE LATE DAY SUNSHINE. COULD ALSO SEE SOME ACTIVITY LATE ACRS WRN AD CNTRL PA..WHICH COULD PSBLY AFFECT THE AVP AREA LATE TDA OR THIS EVNG. BOTTOM LINE IS THAT ANY POTNL REDVLPMNT...IF IT OCCURS...WILL BE VERY LATE. BELIEVE SLGT CHC TO LOW CHC POPS WILL COVER IT FOR THIS AFTN. PREV BLO... PULLED BACK ON POPS OVER NORTHERN HALF OF FA AS MCS REMNANTS WILL BE MORE SCATTERED IN THIS AREA. FOCUS TODAY IS ON SEVERE POTENTIAL DURING THE AFTERNOON HOURS. LATEST NAM SEEMS FAR TOO MOIST IN PUSHING AVP DEW POINT INTO THE UPPER 60S. BASED ON SFC PARCEL TRAJECTORIES FROM MI/OH, IT APPEARS MID 60S IS A REALISTIC RANGE FOR MUCH OF OUR FORECAST AREA. COMBINED WITH FORECAST MAXES OF 78F-82F, WE GET CAPES AROUND 1100-1400 J/KG AND LI`S OF -2C TO -3C. THESE VALUES ARE NOT NEARLY AS UNSTABLE AS INDICATED BY MODELS 24 HOURS AGO. ALSO, THE MODELS HAVE PULLED BACK ON THE MID LEVEL FLOW QUITE A BIT. WE ARE NOW LOOKING AT 30-35 KTS AT MID LEVELS, AS OPPOSED TO THE ORIGINALLY FORECAST 50 KTS. BIG DIFFERENCE, ESPECIALLY GIVEN LACK OF UL JET STREAK. THIS CUTS DOWN ON THE POTENTIAL FOR ORGANIZED CONVECTION. SO THIS EVENT NO LONGER APPEARS SIGNIFICANT. HOWEVER SEVERE POTENTIAL REMAINS, WITH FOCUS LIKELY TO BE INFLUENCED BY BOUNDARIES REMAINING FROM THIS MORNING`S CONVECTION. MAIN THREAT WILL BE FOR MARGINALLY SEVERE HAIL. FLOW ALOFT DOES NOT SEEM TO INDICATE STRONG WINDS WITHOUT A STRONG SQUALL LINE. MORE LIKELY WE WILL SEE SCATTERED, DISCRETE CELLS WITH A FEW PULSING TO SEVERE LEVELS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... THE FIRST PART OF THE WEEKEND DOES NOT LOOK NEARLY AS PESSIMISTIC. THUNDERSTORM REDEVELOPMENT IS POSSIBLE AGAIN LATE FRIDAY, WITH A FEW STRONG CELLS POSSIBLE. AS UPPER LOW DEVELOPS ON SATURDAY, MULTIPLE WAVES WILL ROTATE THROUGH NY AND PA. HOWEVER THE FORCING IS NOT PARTICULARLY STRONG ON ANY GIVEN WAVE. HAVE PULLED BACK POPS TO REFLECT SCATTERED CONVECTION ON SATURDAY, AND KEPT LIKELY WORDING IN FOR SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... MED RANGE MODEL SOLUTIONS CONTINUE TO SHOW REASONABLY GOOD AGREEMENT FOR THIS TIME PERIOD...IN WHAT WILL BE A RATHER UNSETTLED PATTERN TO START OFF...FOLLOWED BY GRADUAL IMPROVEMENT DURING THE MIDDLE OF THE WEEK. PESKY HIGH AMPLITUDE FLOW WITH CUTOFF LOW PRESSURE IN PLACE TO OUR WEST AND NORTH WILL CONTINUE TO FEED THE AREA WITH DEEPER MOISTURE ON SWLY FLOW...ALONG WITH PERIODIC DISTURBANCES EJECTING OUT OF THE MAIN SYSTEM ON SUN-MON. EXPECT MAINLY DIURNALLY DRIVEN SHRA/TSRA...ESPECIALLY SUNDAY WITH AN EXPECTED FROPA. THEN...CUTOFF LOW IS PROGGED TO OPEN AND LIFT THROUGH THE AREA TUESDAY WITH COLD CORE SHOWERS. A RETURN TO DRIER NWLY FLOW AND HIGH PRESSURE ON WEDNSDAY. PRETTY MUCH STAYED WITH CONTINUITY IN THE FCST...BUT MADE SOME ADJUSTMENTS TO RAIN CHANCES MAINLY DURING THE DARK PERIODS WHERE STABILIZATION SHOULD REALLY HELP TO LIMIT COVERAGE OF SHOWERS. ALSO LOWERED POPS BELOW CHC ON TUES NITE/WEDNESDAY WHICH LOOKS RAIN FREE BARRING ANY SLOW DOWN OF TROF PASSAGE. STUCK CLOSE TO 18Z HPC/00Z GMOS TEMPERATURE BLEND. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... IN GENERAL...VFR IS EXPECTED MUCH OF THIS PERIOD. EXCEPTION BEING AREAS OF MVFR VSBY/CIGS THROUGH 15Z-18Z THIS MORNING AS AREAS OF RAIN SHOWERS MOVE THROUGH...FOLLOWED BY DEVELOPING CU. IMPROVEMENT TO VFR SCT-BKN CU/TCU AFT 18Z...HOWEVER TSRA BECOME MORE OF A CONCERN FOR TERMINAL OPERATIONS THROUGH 00Z. TONIGHT...AREAS OF MVFR FOG MAY DEVELOP AT STATIONS WHICH RECEIVE RAINFALL. KELM MAY DEVELOP VLIFR FOG AFT 06Z. OUTLOOK... FRI...VFR. FRI NITE THRU MON...AREAS OF MVFR IN TSRA/SHRA. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJP NEAR TERM... SHORT TERM...DJP LONG TERM...JAB AVIATION...JAB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 321 PM MDT THU JUN 26 2008 .SHORT TERM... (TONIGHT AND FRIDAY) ...MAIN CONCERN IS "DRY" THUNDERSTORMS I-25 CORRIDOR/MOUNTAINS/HIGH VALLEYS AND "WET" STRONG/SEVERE THUNDERSTORMS SOUTHEAST CO THROUGH THIS EVENING AND AGAIN FRIDAY AFTERNOON... CURRENTLY...WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES DID SHOW A FRAGMENTED 500-300MB SHORTWAVE TROUGH MOVING NORTHEASTWARD OUT OF THE DESERT SOUTHWEST AND FOUR CORNERS AREA THIS MORNING AND EARLY AFTERNOON. I WAS THINKING...AND STILL...THIS MIGHT BE THE TRIGGER FOR AT LEAST ISOLATED SHOWERS/THUNDERSTORMS TO DEVELOP. REGIONAL RADAR DID SHOW THE FIRST SHOWERS/THUNDERSTORMS DEVELOPING ALONG THE PALMER DIVIDE AND NORTH CENTRAL CO MOUNTAINS EARLY THIS AFTERNOON. THE LOW LEVEL FUEL HAS BEEN "MIXING OUT" WITH SURFACE DEW POINTS DROPPING INTO THE 20S AND TEEN ALONG I-25 CORRIDOR PUEBLO TO RATON MESA AND ACROSS THE MOUNTAINS/HIGH VALLEYS. DEW POINTS IN THE 40S TO LOWER 50S WERE HANGING ON ACROSS THE PALMER DIVIDE INTO THE FAR SOUTHEASTERN CO PLAINS...BUT WITH RELATIVELY DRIER AIR ALOFT...THESE DEW POINTS MAY TANK...TOO. SURFACE TEMPERATURES PRETTY WARM...WELL IN THE 90S...APPROACHING 100F...BELOW 6K FT MSL. REST OF THIS AFTERNOON AND TONIGHT...I HAVE DEFINITELY TRIMMED BACK POPS/WX ALONG THE I-25 CORRIDOR AND ACROSS THE MOUNTAINS/HIGH VALLEYS. GIVEN THE POTENTIAL TRIGGER SHORTWAVE MOVING THROUGH THE CENTRAL ROCKIES ALONG WITH ENOUGH HEATING AND INSTABILITY...THERE IS STILL A CHANCE FOR ISOLATED THUNDERSTORMS TO DEVELOP ACROSS MUCH OF THE COUNTY WARNING AREA THROUGH THIS EVENING. PRIMARY STORM TYPE SHOULD BE PULSE DOWNBURST WINDS ALONG I-25 CORRIDOR PUB-RATON MESA AND ACROSS THE MOUNTAINS/HIGH VALLEYS. A FEW STRONG TO MAYBE MARGINAL SEVERE MIGHT BE POSSIBLE FROM THE PALMER DIVIDE TO THE FAR SOUTHEASTERN CO PLAINS GIVEN A LITTLE MORE CONVECTIVE AVAILABLE ENERGY IN THESE AREAS THIS EVENING. GENERALLY ALONG THE I-25 CORRIDOR AND MOUNTAINS/HIGH VALLEYS...ISOLATED "DRY" THUNDERSTORMS WILL BE THE RULE GIVEN VERY LOW HUMIDITY VALUES IN THE SUB-CLOUD LAYER PER THE CLASSIC INVERTED-V SOUNDING DATA...ESPECIALLY WITH LCL HEIGHTS ABOUT 2K-4K FT HIGHER THAN THE FREEZING LEVEL AND A VERY UNSTABLE AND "DRY" SUB-CLOUD LAYER. PRIMARILY LOOKING AT CLOUD TO GROUND LIGHTNING STRIKES...WIND GUSTS UP TO 55 MPH...AND VERY LITTLE OR NO RAINFALL. COVERAGE SHOULD BE RATHER LOW...SO NO RED FLAG WILL BE ISSUED FOR DRY LIGHTNING...BUT "DRY THUNDERSTORMS" WILL BE MENTIONED IN THE FWF TEXT PRODUCT. FRIDAY...A CHALLENGING DAY. MODELS STILL SUGGEST A COLD FRONT TO MOVE THROUGH EAST CENTRAL AND SOUTHEAST CO PRIMARILY DURING THE AFTERNOON. TRYING TO TIME THESE BOUNDARIES ARE QUITE THE CHALLENGE...AS SOMETIMES THEY ARE FASTER. I REALLY DON`T SEE ANY SIGNALS OF A FASTER FRONTAL PUSH OVERNIGHT AND FRIDAY MORNING. SO WILL PLAN ON THE FRONT "OOZING" INTO EAST CENTRAL AND SOUTHEAST CO DURING THE AFTERNOON. THE AIR MASS AHEAD AND BEHIND THIS BOUNDARY WILL BE DRASTICALLY DIFFERENT. SOUTH AND WEST OF THE BOUNDARY...VERY LOW DEW POINTS WILL CONTINUE...WHILE SURFACE DEW POINTS IN THE 40S/50S WILL BE COMMON BEHIND THE FRONT. GENERALLY...ALONG THE FRONTAL BOUNDARY AND SOUTH AND WESTWARD...THERE IS VERY LITTLE CHANCE FOR PRECIPITATION AND MAINLY A "DRY" THUNDERSTORM OR "VIRGA SHOWER BOMBS" THREAT...ESPECIALLY OVER THE MOUNTAINS/HIGH VALLEYS AGAIN. AGAIN...THINK THE POTENTIAL COVERAGE IS LOW ISOLATED AT BEST...SO NO FIRE WEATHER WATCH FOR DRY LIGHTNING...BUT WILL MENTION "DRY" THUNDERSTORMS IN THE FWF AND DISCUSSION FOR THESE AREAS. AHEAD OF THE FRONTAL BOUNDARY...TEMPERATURES WILL BE VERY WARM/HOT...PROBABLY 90S TO AROUND 100F AGAIN. ALONG AND BEHIND THE FRONT WILL BE MORE OF A "WET" THUNDERSTORM POTENTIAL WITH SOME STORMS POSSIBLY STRONG-SEVERE. SURFACE-BASED CAPES WILL BE 1K-2.5K J/KG WITH SURFACE-BASED LIFTED INDICES OF -4C TO -6C...WHICH CONVECTIVE ARE VERY RESPECTABLE IN TERMS OF INSTABILITY AND AVAILABLE ENERGY. ASSUMING THE NAM-WRF IS CORRECT WITH ITS SURFACE DEW POINT FORECAST OF 50S DEW POINTS BEING SHOVED UP AGAINST THE EASTERN MOUNTAINS. THERE WILL BE WEAK CONVECTIVE INHIBITION ALONG AND BEHIND THE FRONT...BUT THERE MIGHT BE ENOUGH LOW LEVEL CONVERGENCE TO FORCE A BREAK-THROUGH TO FREE CONVECTION. 0-6KM BULK SHEAR VALUES WILL BE 30-50KTS...WHICH COULD SUPPORT SUPERCELLS. IT MAY BE A MIX OF ORDINARY...MULTICELLULAR...AND SUPERCELLS ALONG AND JUST BEHIND THE FRONTAL BOUNDARY. IF THE LOW LEVEL BOUNDARY IS SLOW OR STATIONARY...THEN A BRIEF TORNADO COULD NOT BE RULED OUT...BUT THE PROBABILITY IS PRETTY LOW. METZE .LONG TERM... FRIDAY NIGHT THROUGH THURSDAY) ...MAIN CHALLENGE IS STRENGTH AND AMOUNT OF CONVECTION SATURDAY... .FRIDAY NIGHT AND SATURDAY...SURFACE COLD FRONT SHOULD PASS THROUGH THE REGION BY MID EVENING FRIDAY WITH UPSLOPE FLOW CONTINUING ON THE PLAINS AND EASTERN MOUNTAINS INTO SATURDAY. NAM AND GFS HAS DEWPOINTS IN THE LOWER 50S ON THE PLAINS SATURDAY. WITH MODEST NORTHWEST FLOW ALOFT...BULK SHEARS ARE FORECAST TO BE AROUND 30 KNOTS WHICH IS IN THE LOWER END OF THE RANGE FOR SEVERE CONVECTION. HAVE SOME CONCERNS FOR THE AMOUNT OF CONVECTION ON SATURDAY. MODEL SOUNDINGS SHOW A CAP AROUND 650 MB THOUGH THE MORNING. IN THE AFTERNOON THE CAP WEAKENS IN THE MODELS...BUT THIS MAY BE THE RESULT OF THE CONVECTIVE SCHEMES GETTING INITIATED. GFS AND NAM HAVE A SHORTWAVE PASSING TO THE NORTHEAST DURING THE MORNING...AND THE SUBSIDENCE BEHIND THIS SHORTWAVE MAY BE STRENGTHENING THE INVERSION. DECIDED NOT TO MAKE MAJOR CHANGES TO THE POP GRIDS AT THIS TIME...WITH THE BEST CHANCES FOR CONVECTION OVER THE EASTERN MOUNTAINS AND INTERSTATE 25 CORRIDOR. CAP WOULD BE WEAKER IN THESE LOCATIONS...AND POOLING OF MOISTURE ALONG THE MOUNTAINS WILL TEND TO INCREASE INSTABILITY. MODEL CAPE FIELDS SUGGEST A SIMILAR PATTERN FOR CONVECTION. OVER THE REMAINDER OF THE AREA...NORTHWEST FLOW AND SUBSIDENCE BEHIND THE TROUGH WILL TEND TO DRY OUT THE ATMOSPHERE. KEPT 10 POPS FOR THE AFTERNOON WITH THE POTENTIAL FOR A FEW MOSTLY DRY THUNDERSTORMS. .SUNDAY AND MONDAY...AS RIDGE TO THE WEST STRENGTHENS...FLOW ALOFT WILL BECOME NORTH NORTHERLY. LOWER LEVELS WILL GRADUALLY DRY WITH DECREASED CHANCES FOR THUNDERSTORMS ON THE PLAINS. WITH WEAK HIGH PRESSURE STAYING TO THE EAST...DID NOT WANT TO REMOVE POPS ENTIRELY. SUSPECT THERE WILL BE ENOUGH LOW LEVEL MOISTURE IN WEAK UPSLOPE FLOW TO GENERATE SOME THUNDERSTORMS...WITH THE GREATEST CHANCES FOR CONVECTION OVER THE EASTERN MOUNTAINS. IN THE REMAINING AREAS...GFS AND EC CONTINUES TO HAVE A WEAK MONSOON LIKE PLUME OF MID LEVEL MOISTURE INTO WESTERN COLORADO. WILL KEEP SOME ISOLATED POPS FOR AFTERNOON AND EVENING CONVECTION. .TUESDAY THROUGH THURSDAY...RIDGE BUILDS OVER THE REGION...WITH ENSEMBLE MEANS FOR GFS SUGGESTING WEAK LEE TROUGH NEAR THE KANSAS BORDER. EC AND GFS HAVE A RIBBON OF MID LEVEL MOISTURE MOVING NORTH FROM MEXICO. IT LOOKS LIKE SUMMER...AND HAVE A BROAD BRUSH SUMMER FORECAST OF AFTERNOON AND EVENING THUNDERSTORMS WITH BEST CHANCES OVER THE MOUNTAINS. MOISTURE IN MONSOON PLUMES TYPICALLY ARE MODEST THIS TIME OF YEAR AND DO NOT ANTICIPATE SIGNIFICANT PRECIPITATION FROM CONVECTION. --PGW-- && .AVIATION... PER SHORT TERM DISCUSSION...FOR ALL FORECAST TAF...ISOLATED SHOWERS AND THUNDERSTORMS THROUGH THIS EVENING AND FRIDAY AFTERNOON WILL LEAD TO VARIABLE WIND DIRECTION AND SPEEDS OF 20-30KTS WITH GUSTS UP TO 45KTS AT TIMES. METZE && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 17/06 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 323 PM EDT THU JUN 26 2008 .NEAR TERM... MAIN CONCERN IN NEAR TERM IS WITH TSTMS. MCV MOVG ACROSS NW INDIANA THIS AFTN. LAPS SFC BASED CAPES UP TO 4KJ/KG AHEAD OF THIS FEATURE. SFC TROF ALSO EVIDENT FM ERN MI SW TO WEST CENTRAL INDIANA. SCT TSTMS HAVE BEEN FORMING ALONG THIS BOUNDARY THIS AFTN. WITH WK SHEAR AND VERY MOIST/UNSTABLE ENVIRONMENT...STORMS WILL BE MARGINALLY SEVERE WITH GUSTY WINDS... VERY HEAVY RAIN.... AND SOME HAIL. EXPECT THIS ACTIVITY TO PERSIST INTO THE EVE ALONG SFC TROF AND SUBSEQUENT TSTM OUTFLOW BOUNDARIES SO HAVE CONTD WITH SCT POPS THROUGH 00Z SE WITH A CHC NW. FOR THE EVE HOURS INHERITED LIKELY POPS ACROSS THE NORTHERN COUNTIES. GFS WITH SUPPORT FROM RUC13 INDICATING AN AT LEAST PARTIALLY CONVECTIVELY ENHANCED SHRTWV WILL MOVE EAST FROM NW IA THIS AFTN TO ERN WI/NE IL BY 06Z. CURRENTLY MESO-BETA ELEMENTS ASSOCIATED WITH THIS FEATURE WERE MOVG SSE HWVR SOME CONVECTION ALSO PUSHING EAST ACROSS NRN IA. CAN`T RULE OUT MORE WIDESPREAD CONVECTION DVLPG AHEAD OF THIS SHRTWV AND MOVG INTO OUR AREA BY LATE EVE BUT GIVEN CURRENT TRENDS WITH CONVECTION UPSTREAM HAVE LOWERED POPS TO CHC ACROSS NRN PORTIONS OF CWA IN THE 00Z-06Z TIMEFRAME. && .SHORT TERM... LATE TONIGHT INTO FRIDAY AND FRIDAY NIGHT... MAIN CONCERN IS THE SVR WEATHER POTENTIAL FRI INTO FRI NIGHT IN ACTIVE PATTERN AS POTENT UPPER TROUGH DIGS INTO THE NRN PLAINS AND UPPER MIDWEST FRI INTO FRI NIGHT. LATE TONIGHT/FRI MORNING...LEFT IN CHC POPS FOR SHOWERS/STORMS AS FA MAY BE IMPACTED BY CONVECTION/MCS CURRENTLY BACK IN IA WITH FURTHER DEVELOPMENT EXPECTED IN THE IA/SRN WI/NW IL VICINITY TONIGHT. 12Z MODELS CONTINUE TO STRUGGLE WITH MESOSCALE DETAILS WITH THE GFS HAVING CONVECTIVE FEEDBACK ISSUES AND THE 12Z NAM INITIALIZING POORLY WITH QPF. HOWEVER...AM CONFIDENT THAT AN ADDITIONAL MCS WILL DEVELOP OUT TO THE W WITH INCREASING LL CONV AHEAD OF POTENT UPPER TROUGH ALONG THETA-E/MOISTURE GRADIENT. WOULD THINK THAT THIS WOULD TRACK EASTWARD FOLLOWING PROGGED CORFIDI VECTORS/7H FLOW. ALSO WOULD EXPECT THE MCS TO TRACK NEAR/JUST SOUTH OF STRONG INSTABILITY/THETA-E BOUNDARY FROM LOWER MICHIGAN WNW TOWARD THE IL/WI BORDER. WITH THIS SAID...THINK THIS FEATURE WILL WEAKEN AS IT OUTRUNS BETTER FORCING WITH TRACK/SPEED IN QUESTION DUE TO LACK OF ANY GOOD MODEL GUIDANCE. AS A RESULT...WILL KEEP WITH CHC POPS DURING THIS TIMEFRAME DUE TO CONTINUED UNCERTAINTY. FRIDAY AFTERNOON...DEPENDING ON EVOLUTION OF MCS RENMANTS IT ONCE AGAIN LOOKS LIKE THE ATMOSPHERE WILL BECOME VERY UNSTABLE AS STEEPENING MID LEVEL LAPSE RATES COMBINED WITH VERY MOIST LOW LEVELS WILL YIELD MLCAPES AOA 2500 J/KG. NO OBVIOUS TRIGGER FOR SHOWER/STORM DEVELOPMENT WITH TIGHT THETA-E GRADIENT/DIFFUSE SFC TROUGH RETREATING OFF TO THE NORTH IN REPONSE TO HEIGHT FALLS ACROSS THE NORTH CENTRAL US. IF INSTABILITY IS REALIZED THINK IT WILL BE ENOUGH TO BREAK WEAK CAP NEAR 12KFT FOR SCT SHOWERS/STORMS...ESPECIALLY WITH OUTFLOW BOUNDARIES AROUND. DEEP LAYER SHEAR NEEDED FOR ROTATING UPDRAFTS/SUPERCELLS WILL LIKELY STAY OFF TO THE WEST...HOWEVER...HAIL/MICROBURST MULTICELLS A DISTINT POSSIBLITY WITH IMPRESSIVE CAPE...STEEP LL LAPSE RATES...AND SOMEWHAT DRY MID-LEVELS. FRIDAY NIGHT...MORE ORGANIZED SHOWER/STORM ACTIVITY SHOULD INITIATE FRI AFTN ALONG AND JUST AHEAD OF A PRE-FRONTAL TROUGH FROM NEAR MCI NE THRU DSM AND GRB. THIS ACTIVITY WILL LIKELY START OUT AS DISCRETE SUPERCELLS AND THEN ORGANIZE INTO A COLD POOL DRIVEN SQUALL LINE/LEWP...POSSIBLY AFFECTING THE REGION FROM WEST TO EAST FRI NIGHT. SVR WX A CONCERN WITH THIS AS IT MOVES THROUGH. DO NOT EXPECT THIS TO FALL APART AS WE LOSE DAYTIME HEATING DUE TO LARGE SCALE FORCING WITH DIFF PVA/HEIGHT FALLS...DIFFLUENT FLOW ALOFT IN RIGHT ENTRANCE REGION OF 100KT JET ROUNDING BASE OF TROUGH...AND LL CONV ALONG SFC TROUGH/OUTFLOW. CONTINUED WITH LIKELY POPS FOR FRIDAY NIGHT AND INCLUDED A SEVERE MENTION IN THE GRIDS. HEAVY RAIN DEFINITELY POSSIBLE FRIDAY INTO FRIDAY NIGHT WITH PWATS INCREASING TO NEAR 2 INCHES AND A DEEP WARM CLOUD LAYER NEAR 10KFT. && .LONG TERM... LITTLE CHANGE TO LONG TERM WITH OVERALL PACKAGE IN GOOD SHAPE. UNSETTLED WEATHER ON TAP FOR SATURDAY AFTERNOON WITH FRONTAL PASSAGE AND AGAIN ON SUNDAY WITH COLD AIR ALOFT AND MID LEVEL SHORTWAVE. MODELS ARE FAIRLY USELESS ON DETAILS FOR SATURDAY WITH THE NEAR TERM SO MUDDLED THAT INITIALIZATION ISSUES ABOUND. BUT THE LARGER DETAILS ARE STILL CONSISTENT SHOWING UPPER LOW SETTLING OVER GREAT LAKES AND ASSOC SFC FRONT ROLLING THROUGH ON SATURDAY AFTERNOON. MOISTURE/INSTABILITY SHOWN BY BUFR SOUNDINGS TO BE WELL ESTABLISHED AHEAD OF THE BNDRY. WHILE ACTIVITY COULD FIRE EARLY ALONG PRE FRONTAL TROF INDICATED BY NAM IT WILL LIKELY TURN OUT...AS HAS BEEN THE CASE IN RECENT DAYS...THAT DETAILS OF THE AFTERNOON EVOLUTION WILL BE LARGELY DEPENDENT ON FEATURES REMAINING FROM FRIDAY NIGHTS ACTIVITY TO THE WEST. COLD POOL THEN SETTLES IN WITH MODELS POORLY HANDLING STRENGTH AND LOCATION FROM RUN TO RUN WITH LARGE TIMING DIFFERENCES ON H5 SHORTWAVE ROTATING AROUND LOW. KEPT AFTERNOON POPS INTACT AND DID NOT ADD ANYTHING IN MORNING HOURS DUE TO LOW CONFIDENCE. DEEP LOW OVER EASTERN NA LIFTS WITH BROADER TROFING IN ITS WAKE KEEPING AREA UNDER UPPER NW FLOW THROUGH THE WEEK. && .PREV DISCUSSION... /ISSUED 131 PM EDT THU JUN 26 2008/ AVIATION... THUNDERSTORMS HAVE DEVELOPED OVER THE WESTERN AND SOUTHERN PORTIONS OF THE FORECAST AREA. THESE SHOULD NOT IMPACT KSBN UNTIL MID AFTERNOON BUT WILL TRACK NORTHEAST TOWARDS KFWA. MORE DEVELOPMENT UPSTREAM OVER IOWA WILL PROPAGATE TOWARDS THE REGION WITH POTENTIAL AFFECTS ON TERMINALS OVERNIGHT INTO FRIDAY MORNING. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...STEINWEDEL LONG TERM...LUDINGTON AVIATION...LUDINGTON NEAR TERM...TAYLOR in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 113 PM CDT THU JUN 26 2008 .UPDATE... && .AVIATION...18Z TAFS [RSL/SLN/HUT/ICT/CNU] VFR CONDITIONS EXPECTED DURING THE VALID PERIOD. LEE TROF WILL LEAD TO SRLY WIND GUSTS (25-30KT) THIS PM IN CNTRL/S-CNTRL KS. WINDS WILL BECOME W-SWRLY TOWARD END OF VALID PERIOD JUST AHEAD OF APPROACHING COLD FRONT. JMC && PREV DISCUSSION... /ISSUED 316 AM CDT THU JUN 26 2008/ DISCUSSION... FORECAST CONCERNS...CONVECTIVE CHANCES/TRENDS AND SEVERE POTENTIAL FRIDAY AFTERNOON THROUGH FRIDAY NIGHT. ONLY SUBTLE CHANGES IN SENSIBLE WEATHER EXPECTED FOR TODAY...SO WILL FOLLOW A MODIFIED PERSISTENCE APPROACH TO THE FORECAST AND MOST GRID ELEMENTS TODAY. A BIT MORE OF A CAP EARLY THIS MORNING BASED ON RUC MODEL...SO HOPEFULLY WILL NOT SEE ANOTHER SUNRISE SURPRISE TOWARD DAWN...ISOLATED AS IT WAS YESTERDAY. OTHERWISE EXPECT A COUPLE LOCALES TO APPROACH/TOUCH THE CENTURY MARK ACROSS CENTRAL KANSAS THIS AFTERNOON. DESPITE MAXS IN THE LOW/MID 90S FOR THE REST OF THE AREA...IT WILL FEEL CLOSE TO 100 WITH COMBO OF HEAT AND HUMIDITY. CONVECTION THAT DEVELOPS NORTHWEST OF THE AREA THIS EVENING MAY CLIP NORTHERN PORTIONS OF THE FORECAST AREA TONIGHT...SO WILL KEEP A SLIGHT CHANCE IN FOR THOSE AREAS. HOWEVER...MAIN FOCUS FOR MORE ORGANIZED CONVECTION WILL COME LATER FRIDAY INTO EARLY SATURDAY MORNING...AS A STRONG SUMMER-TIME UPPER TROF AND THE ASSOCIATED COLD FRONT DROPS SOUTHEAST ACROSS THE MIDWEST. THIS TROF WILL DEEPEN ACROSS THE GREAT LAKES WITH A REINFORCING SHOT OF COOLISH/DRIER AIR SATURDAY NIGHT INTO SUNDAY. THE FRONT ON FRIDAY EVENING LOOKS TO ENCOUNTER A VERY UNSTABLE AIRMASS ACROSS EASTERN KANSAS...AND CONFIDENCE CONTINUES BUILD ON A SEVERE CONVECTIVE EPISODE...SO HAVE UPPED POPS INTO THE LIKELY CATEGORY FOR AREAS EAST OF THE KANSAS TURNPIKE FRIDAY NIGHT. STILL SOME QUESTION AS TO THE TIMING/SOUTHWARD MOVE OF THE FRONT...WITH THE NAM MORE PROGRESSIVE THAN OTHER MODELS. THIS MAY HAVE MORE OF AN IMPACT ON MAXS FOR CENTRAL KANSAS ON FRIDAY...AND FOR NOW WILL STILL KEEP THINGS QUITE TOASTY...HOWEVER AREAS OF SOUTH CENTRAL LOOK TO BE THE HOTTEST...ESPECIALLY FOR AREAS WEST AND SOUTHWEST OF GREATER WICHITA WHERE PERHAPS A DRIER SOUTHWEST FLOW AND SOME COMPRESSIONAL WARMING EFFECTS WILL ENHANCE MAX POTENTIAL LATE IN THE AFTERNOON. OTHERWISE...HAVE TEMPERED MAXS FOR THE WEEKEND...ESPECIALLY FOR SUNDAY...WITH MODEL CONSENSUS SUGGESTING RELATIVELY COOLER AIR WILL HOLD SWAY THRU THE WEEKEND NOW. DARMOFAL AVIATION... 06Z TAFS...ICT/SLN/HUT/CNU/RSL...VFR CONDITIONS ANTICIPATED OVER THE NEXT 24 HOURS. STRENGTHENING AND VEERING LOW-LEVEL JET TONIGHT MAY INITIATE A STRAY THUNDERSTORM SOMEWHERE ACROSS CENTRAL AND SOUTHEAST KANSAS TONIGHT...BUT PREDICTABILITY IS TOO LOW AND COVERAGE TOO SPARSE TO MENTION VCTS IN THE TAFS. OTHERWISE...STOUT SOUTHERLY WINDS WILL COMMENCE BY MID-MORNING THURSDAY...AS LOW PRESSURE STRENGTHENS ACROSS THE WESTERN HIGH PLAINS...AND A COLD FRONT GETS ITS ACT TOGETHER NORTHWEST OF THE AREA. KLEINSASSER && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 95 73 97 71 / 10 10 20 50 HUTCHINSON 96 72 98 69 / 10 10 30 50 NEWTON 95 73 97 70 / 10 10 30 50 ELDORADO 94 73 95 71 / 10 10 20 60 WINFIELD-KWLD 94 73 96 72 / 10 10 20 60 RUSSELL 100 71 95 66 / 10 20 40 20 GREAT BEND 99 71 97 67 / 10 10 40 30 SALINA 99 73 97 68 / 10 20 40 40 MCPHERSON 97 73 97 69 / 10 10 40 40 COFFEYVILLE 92 72 93 72 / 10 10 20 60 CHANUTE 92 72 93 72 / 10 20 20 60 IOLA 92 72 93 72 / 10 20 20 60 PARSONS-KPPF 92 72 93 72 / 10 10 20 60 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 227 PM EDT THU JUN 26 2008 .SHORT TERM.../THE REST OF TODAY/ THE MAIN FOCUS FOR THE UPDATE THIS MORNING WILL DEAL WITH THE THREAT FOR AFTERNOON THUNDERSTORMS. THE MAIN CHANGE TO POPS WAS TO ADD A FEW MORE COUNTIES A LITTLE FURTHER SOUTH IN THE CHANCE POP RANGE. CURRENT WATER VAPOR IMAGERY/RUC 13 SHOW THE POTENTIAL FOR AN APPROACHING WEAK SHORT WAVE TO INFLUENCE COUNTIES MAINLY NORTH OF INTERSTATE 64. THE FEELING IS THAT SCATTERED COVERAGE WOULD REPRESENT THE AREA INFLUENCED BY THE WAVE AND ISOLATED COVERAGE WOULD REPRESENT THE AREAS FURTHER SOUTH WHO NEED TO REACH THEIR CONVECTIVE TEMPS. LAPS AND FORECAST SOUNDINGS SHOW A WEAK WIND PROFILE THROUGH THE ENTIRE COLUMN...SO ANY ORGANIZED THUNDERSTORMS WOULD BE VERY HARD TO COME BY. THE BEST CHANCE FOR ANY ORGANIZATION WOULD BE IN THE NORTH WHERE BETTER FORCING FOR ASCENT WILL BE ASSOCIATED WITH THE WEAK SHORTWAVE. CURRENT SURFACE OBS SHOW 14Z TEMPERATURES WELL ON THEIR WAY TO THE UPPER 80S TO AROUND 90 DEGREES. DID NOT CHANGE MUCH IN THE WAY OF TEMPERATURES...ONLY MADE A FEW MINOR TWEAKS BASED ON CURRENT TRENDS. EXPECT MOISTURE TO CONTINUE TO INCREASE TODAY...SETTING UP THE APPROACHING WEEKEND SYSTEM. UPDATED ZFP OUT SHORTLY. THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS... /TODAY THROUGH FRIDAY NIGHT/ MOISTURE RETURN WILL GRADUALLY INCREASE ACROSS EASTERN KENTUCKY TODAY AS UPPER RIDGE WEAKENS AND MOVES OFF TO THE EAST AND SOUTHEAST. FLOW PATTERN WILL TRANSITION TO MORE ZONAL...LEAVING US OPEN TO MORE EMBEDDED WEAK SHORT WAVES. HAVE MAINTAINED ISOLATED POPS FOR ALL TODAY WITH CONVECTIVE TEMPERATURES LIKELY BEING REACHED FOR SOME. BETTER CHANCE WILL EXIST IN THE BLUEGRASS COUNTIES CLOSER TO THE TRAIN OF TRAVERSING WEAK DISTURBANCES ALONG WITH AMPLE MOISTURE RETURN...SO HAVE GONE WITH SCATTERED CONVECTION IN THE AFTERNOON. STUCK CLOSER TO THE NAM MOS FOR HIGHS AT JKL...WHILE USING THE GFS MOS FOR LOZ AND SME. SCATTERED CONVECTION WILL RE-FIRE FRIDAY AFTERNOON INTO FRIDAY EVENING AS WE BECOME MORE UNDER THE INFLUENCE OF TROUGHING TAKING PLACE ACROSS THE NORTHERN PLAINS WITH ADDITIONAL WEAK DISTURBANCES MOVING TOWARDS THE AREA. INCREASED CLOUD COVER WILL KEEP HIGHS A BIT COOLER ON FRIDAY...HOWEVER CONTINUED MOISTURE ADVECTION WILL KEEP THE AIR MASS VERY MUGGY. USED A BLEND OF PERSISTENCE AND THE LATEST GUIDANCE FOR TEMPERATURES FROM TONIGHT THROUGH FRIDAY NIGHT. .LONG TERM.../SATURDAY THROUGH WEDNESDAY/ THE MAIN FOCUS FOR THE LONG TERM FORECAST PERIOD WILL DEAL THE APPROACH AND ARRIVAL OF A COLD FRONT ASSOCIATED WITH AN UNSEASONABLY STRONG UPPER LEVEL LOW TO THE NORTHWEST. HAVE DECIDED TO BLEND BETWEEN THE GFS/ECMWF SOLUTIONS AS SLOWER AND MORE SOUTHERLY TRACK SEEMS TO BE THE WAY TO GO. THE LATEST HPC DISCUSSIONS SEEMS TO AGREE WITH THIS DECISION AS WELL. AS A RESULT...HAVE SLOWED THE SYSTEM DOWN WHICH WILL GIVE US PRETTY GOOD CHANCES FOR RAIN...POSSIBLY HEAVY AT TIMES...STARTING SATURDAY AND ENDING SUNDAY AFTERNOON. AN INTERESTING SETUP WITH SURFACE HIGH PRESSURE OFF THE SOUTHEAST COAST SHOULD PROVIDE PLENTY OF MOISTURE RETURN AHEAD OF THE SYSTEM ON SATURDAY. UPLIFT FROM MULTIPLE WAVES EMBEDDED IN THE HIGHLY AMPLIFIED H5 TROUGH WILL ALLOW FOR CONTINUING CHANCES OF PRECIPITATION. HAVE SLIGHTLY INCREASED POPS TO GOOD CHANCE AND LIKELY FOR MOST OF THE EVENT. LATEST GUIDANCE VALUES ALSO CAME IN WITH HIGHER POPS ADDING CONFIDENCE TO THE FORECAST. BASED ON NAM/GFS FORECAST SOUNDINGS...SOME CONCERN IS STARTING TO GROW WITH REGARD TO HEAVY RAINFALL POSSIBLE LATE SATURDAY AFTERNOON AND NIGHT. VERY MOIST/TROPICAL LIKE SOUNDINGS SHOW TALL SKINNY CAPE PROFILES AND PWAT VALUES AROUND 2 INCHES ON SATURDAY. SOUTHWEST TO NORTHEAST LINEAR FORCING ASSOCIATED WITH THE FRONT AND FAIRLY SLOW STORM MOTIONS PARALLEL TO THIS COULD RESULT IN TRAINING OF VERY EFFICIENT THUNDERSTORMS. WILL HAVE TO MONITOR THIS SITUATION CLOSELY AND KEEP THE NAM MOISTURE BIAS IN MIND. HAVE DECIDED TO MENTION THE POSSIBILITY OF THE THREAT FOR LOCALLY HEAVY RAINFALL IN THE HWO. THE COLD FRONT FINALLY MOVES THROUGH SOMETIME ON SUNDAY WITH POPS ENDING LATE SUNDAY AFTERNOON. HAVE KEPT THE REST OF THE EXTENDED DRY FOR NOW...HOWEVER LINGERING MOISTURE AND ANY WAVES EMBEDDED IN THE RETREATING H5 TROUGH COULD ALLOW FOR SOME VERY ISOLATED COVERAGE. TOO MUCH UNCERTAINTY EXISTS AT THIS POINT TO INCLUDE SLIGHT CHANCE POPS. AS FAR AS TEMPERATURES GO...DID NOT MAKE MANY CHANGES. ONLY MADE A FEW MINOR ADJUSTMENTS BASED ON LATEST GUIDANCE VALUES. && .AVIATION.../18Z TO 18Z/...UPDATED ISOLATED THUNDERSTORMS HAVE DEVELOPED OVER THE AREA AND EXPECT THESE TO CONTINUE INTO EARLY EVENING BUT SHOULD NOT INCREASE COVERAGE MUCH. WILL UPDATE TAFS THIS AFTERNOON ONLY IF A CLUSTER OF STORMS APPROACHES. BELIEVE VCTS WILL SUFFICE. OTHERWISE THINK THERE IS ENOUGH RIDGE REMAINING ONCE THE HEATING IS LOST TO KEEP THUNDER FROM APPROACHING WITH THE SHORTWAVE FROM IL LATE TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...GEOGERIAN/SCHOETTMER LONG TERM....SCHOETTMER AVIATION...GV ky AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 215 PM EDT THU JUN 26 2008 UPDATED AVIATION SECTION FOR 18Z TAFS .UPDATE... DUE TO LAST NIGHTS RAIN/LIGHT WINDS/50S DEWPOINTS...WIDESPREAD FOG DEVELOPED OVER LAKE SUPERIOR AND ADJACENT AREAS OF NORTHERN UPR MI LATE LAST NIGHT. NW/N WINDS OVR LK SUPERIOR AND IN AREAS EAST OF KEWEENAW PENINSULA TO WHITEFISH POINT WILL KEEP SOME FOG AND LOW CLOUDS INTO EARLY AFTN...AT LEAST ALONG THE IMMEDIATE SHORE. FOG OVR KEWEENAW IS ALREADY LIFTING...DUE TO WEAK ADVECTION OF DRY AIR HANGING OUT OVR WESTERN LAKE SUPERIOR. ONSHORE FLOW/CLOUDS/FOG SHOULD KEEP TEMPS IN THE UPR 50S TO UPR 60S ALONG LAKE SUPERIOR SHORE EAST OF THE KEWEENAW PENINSULA. MAINLY SUNNY SKIES INLAND AND STILL WARM H85/H8 TEMPS LEAD TO MAX TEMPS REACHING WELL INTO THE 80S OVR SCNTRL SECTIONS AWAY FM BAY OF GREEN BAY. MODIFIED GRB SOUNDING FOR T/TD OF 85/63 AND THAT DID GIVE SBCAPE AOA 1000 J/KG. HOWEVER ...DRY MID LEVEL AIR IS EVIDENT AS IS SOME CAPPING AROUND 750MB AND LARGE SCALE FORCING FOR ANY SHOWERS IS NIL. ABOUT THE ONLY TRIGGER WOULD BE LAKE BREEZE FRONT OFF LAKE MICHIGAN...BUT THAT WOULD APPEAR TO BE PRETTY SHALLOW AND NOT SUFFICIENT TO KICK OFF ANY CONVECTION. && .DISCUSSION (530 AM EDT)... MAIN CONCERNS FOCUS ON TIMING OF CONVECTION ON FRIDAY AND POSSIBLE SVR STORMS...THEN LINGERING SHRA/TSRA INTO THE WEEKEND. WATER VAPOR LOOP AND RUC ANALYSIS CONTINUE TO SHOW ZONAL FLOW ACROSS THE NRN CONUS. SHORTWAVE RESPONSIBLE FOR LAST NIGHT`S CONVECTION HAS MOVED EAST OF THE AREA. IR SATELLITE NOW SHOWS CLEARING SKIES FROM THE WEST AS MID LVL RDGG AND SUBSIDENCE NOSE INTO THE AREA. HOWEVER...DEWPOINTS REMAIN FAIRLY HIGH (UPR 50S TO LOW 60S) AND FOG LINGERS OVER MUCH OF LAKE SUPERIOR EARLY THIS MORNING AND OVER THE SHORELINE AREAS. TODAY...EXPECT AREAS OF FOG NEAR THE LAKE SUPERIOR SHORELINE TO LIFT AFTER SUNRISE WITH SUNNY SKIES PREVAILING UNDER MID-LVL RIDGING AND SUBSIDENCE. 800 MB TEMPS NEAR 12C MIXING TO THE SFC SHOULD YIELD HIGHS IN THE LOWER 80S OVER THE WRN INTERIOR. LAKE BREEZES DEVELOPING WILL KEEP TEMPS COOLER (LOWER 70S) NEAR THE GREAT LAKES AND OVER THE ERN FCST AREA. TONIGHT...EXPECT DRY CONDITIONS TO CONTINUE UNDER THE INFLUENCE OF THE SFC HIGH ALTHOUGH THERE WILL BE SOME INCREASE IN WAA MID-HIGH LVL CLOUDS FROM THE SW LATE AHEAD OF NEXT INCOMING SHORTWAVE. EXPECT LOWS TO GENERALLY BE IN THE MID 50S WITH SLIGHTLY COOLER READINGS EAST WHERE SKIES SHOULD BE CLEAR MOST OF THE NIGHT. FRIDAY...GENERALLY FOLLOWED A BLEND OF THE NAM/UKMET/ECMWF AND SREF MODELS AS THE GFS AND EVEN THE GLOBAL GEM LOOK TO BE AFFECTED BY CONVECTIVE FEEDBACK. ALL THESE MODELS BRING THE LEAD SHORTWAVE INTO THE AREA ON FRI AHEAD OF AN UPR TROF/CLOSED LOW DEVELOPING OVER THE NRN PLAINS. 305K ISENTROPIC ASCENT ASSOC WITH THIS SHORTWAVE WILL SUPPORT THE INITIAL BATCH OF CONVECTION SPREADING SW TO NE ACROSS THE FCST AREA...MAINLY LATE FRI. BUMPED UP POPS TO LIKELY ACROSS WEST AND CENTRAL PORTIONS SINCE MODELS HAVE COME INTO BETTER AGREEMENT ON TIMING/COVERAGE OF SHRA/TSRA. STRONG MOISTURE INFLOW WITH PWAT INCREASING TO AOA 1.5 INCHES COULD SUPPORT HEAVY DOWNPOURS WITH THE SHOWERS. MUCAPE VALUES INTO THE 1000-1500 J/KG RANGE AND 0-6KM BULK SHEAR INTO THE 30-40 KT RANGE WILL BE ENOUGH TO SUPPORT SOME STRONGER STORMS. HOWEVER...HIGH FREEZING LEVELS (13-14 KFT) SHOULD LIMIT LARGE HAIL THREAT. SPC STILL HAS THE ENTIRE U.P IN A SLIGHT RISK OF SVR FOR THE DAY2 CONVECTIVE OUTLOOK. FRI NIGHT...AS THE MID/UPPER LEVEL LOW SINKS SLOWLY ESE TOWARD THE UPPER GREAT LAKES...A DRY SLOT WILL SPREAD THROUGH THE AREA REDUCING PCPN CHANCES. FOLLOWED THE PREFERRED SLOWER TIMING OF THE ECMWF AND SREF WITH THIS FEATURE SO KEPT IN SHRA/TSRA CHANCES WITH THE HIGHEST POPS OVER THE EASTERN FCST AREA. SAT INTO SUN...FOLLOWED THE NCEP PREFERRED GFS ENSEMBLE MEAN SOLN WITH MVMT OF THE UPR LOW WHICH IS SIMILAR TO THE OPERATIONAL 00Z ECMWF RUN. FCST 500 MB TEMPS OF -17C/-18C WITH STEEP LOW-MID LEVEL LAPSE RATES AND FORCING FROM SHORTWAVES ROTATING AROUND THE LOW WILL SUPPORT SCT SHRA/TSRA THROUGH THE PERIOD. BY SUN...WITH NRLY LOW LEVEL FLOW DEVELOPING...MUCH COOLER WEATHER IS EXPECTED ESPECIALLY ALONG LAKE SUPERIOR. THERE WILL BE CONTINUED CHCS FOR LIGHT RAIN OR SHOWERS BUT TSTM SHOULD CHANCES SHOULD BE DWINDLING. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... W WINDS BRINGING IN STABLE AIR/CLEAR SKIES AT CMX SHOULD LAST INTO THIS EVENING. LOW PROBABILITY OF FOG THROUGH THE NIGHT AS THERE IS SOME WIND AND BKN MID-HIGH CLOUDS. ON FRI MORNING AT CMX...SE/E WINDS DEVELOP AS LOW PRESSURE MOVES INTO CNTRL MN. WIND DIRECTION AND FOG OUT OVR LAKE SUPERIOR MAY RESULT IN FOG OR LOW STRATUS RETURNING TO THE AIRPORT. VFR CONDITIONS EXPECTED AT SAW THROUGH THIS EVENING...THEN SINCE THERE IS STILL LINGERING LOW LEVEL MOISTURE FROM RECENT RAINS...MAY SEE RADIATION FOG LATE TONIGHT AT SAW. ENOUGH WIND JUST OFF SFC SHOULD KEEP VSBY FM FALLING TOO MUCH. SCT-BKN CU/SC EXPECTED ON FRI AT SAW AS WARMER AIR ALOFT LIFTS TOWARD UPPER MICHIGAN. ANY SHOWERS AND THUNDERSTORMS WILL HOLD OFF TIL LATE FRI AFTN. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... AS HIGH PRESSURE CROSSES LAKE SUPERIOR TODAY THROUGH FRIDAY MORNING WINDS WILL LESS THAN 20 KNOTS. ANOTHER LOW PRESSURE TROUGH WILL MOVE FROM THE NORTHERN PLAINS TONIGHT AND INTO LAKE SUPERIOR ON FRIDAY NIGHT AND REMAIN THROUGH SATURDAY. PRESSURE GRADIENTS WILL TIGHTEN FOLLOWING THE LOW CAUSING WIND TO INCREASE TO 20 TO 25 KNOTS FOR A PERIOD OVER CENTRAL AND EAST EASTERN LAKE SUPERIOR. BY SUNDAY...THE LOW FILLING SLIGHTLY AND SLIDE SOUTHEASTWARD OVER LOWER MICHIGAN BY SUNDAY MORNING WILL CAUSE THE WINDS TO LESS AN 20 KNOTS FOR THE REMAINDER OF THE PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...JLA DISCUSSION...VOSS AVIATION...JLA MARINE...KF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 330 PM EDT THU JUN 26 2008 .SYNOPSIS... A WEAK FRONTAL BOUNDARY WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS TONIGHT. THIS WILL BE FOLLOWED BY A PASSING HIGH PRESSURE SYSTEM THAT WILL BRING US RAIN FREE CONDITIONS TO MOST OF THE AREA FRIDAY. THE WEEKEND WILL THEN BECOME UNSETTLED AS A DEEPENING TROUGH OVER THE GREAT LAKES REGION WILL RESULT IN FREQUENT BOUTS OF SHOWERS AND THUNDERSTORMS. && .NEAR TERM /THROUGH FRIDAY/... CLOUDS LEFT OVER FROM THIS MORNING`S SHOWERS HAS KEPT THE AIR OVER NEW YORK STATE RELATIVELY STABLE COMPARED TO AREAS OVER THE CENTRAL GREAT LAKES AND OHIO VALLEY. THIS HAS PRECLUDED THE DEVELOPMENT OF ANY CONVECTION ACROSS OUR CWA...SO FAR THIS AFTERNOON. THE CLOUDS HAVE THINNED OUT NICELY ACROSS THE NIAGARA PENINSULA...BUT ANY CONVECTION THAT FIRES UP ACROSS THIS AREA LATER THIS AFTERNOON WILL HAVE TO FIGHT THE STABILIZING LAKE ERIE BREEZE. THEREFORE...DO NOT EXPECT ANY ORGANIZED CONVECTION TO TAKE PLACE ACROSS THE NIAGARA FRONTIER THROUGH THE EARLY EVENING. WE WILL HAVE TO MONITOR THE GENESEE VALLEY FOR THE POSSIBILITY OF CONVECTION LATER THIS AFTERNOON INTO THE EARLY EVENING. THIS AREA WILL STILL WARM UP A FEW MORE DEGREES AS THE CLOUDS THIN OUT UNDER THE INFLUENCE OF THE STRENGTHENING LAKE ERIE BREEZE. THE RUC SUGGESTS THAT CAPES MAY INCREASE A LITTLE ABOVE 1000 J/KG WITH LI`S LOWERING TO ABOUT -5. IF TEMPERATURES WARM UP A LITTLE MORE ACROSS THE SOUTHERN TIER...A FEW SHOWERS OR THUNDERSTORMS ARE POSSIBLE ACROSS THIS AREA AS WELL. OUR ATTENTION THEN TURNS TO THE MIDWEST COLD FRONT THAT IS HELPING TO GENERATE STRONG THUNDERSTORMS FROM LOWER LAKE HURON TO CENTRAL INDIANA INTO THE OHIO VALLEY. THIS FRONT IS FORECAST TO MOVE SLOWLY TO THE EAST AND DROP SOUTH ACROSS LAKE ONTARIO TONIGHT BEFORE STALLING OVER CENTRAL/SOUTHERN NEW YORK STATE ON FRIDAY. WILL LEAVE IN A CHANCE OF SHOWERS AND THUNDERSTORMS FOR TONIGHT AS THE FRONT INTERACTS WITH THE MOIST AIR AND SOMEWHAT UNSTABLE AIR THAT WILL STILL BE IN PLACE ACROSS THE AREA. THE ATMOSPHERE WILL BE SOMEWHAT MORE CAPPED ON FRIDAY...BUT WILL LEAVE IN A CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN TIER AND UPPER GENESEE VALLEY WHERE THE WARM UNSTABLE AIR WILL INTERACT WITH THE STALLED FRONT. IF THE FRONT STALLS FARTHER TO THE NORTH...WE MAY HAVE TO INCLUDE A CHANCE FOR SHOWERS/THUNDERSTORMS FOR MOST OF THE CWA. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... THE WEAK SURFACE RIDGE WILL SLIDE EAST OF THE AREA FRIDAY NIGHT AS A POTENT UPPER LEVEL SHORTWAVE OVER THE NORTHERN PLAINS WILL SETTLE ACROSS THE UPPER MIDWEST. A STRENGTHENING SOUTHWEST FLOW BETWEEN THESE TWO FEATURES WILL ADVECT INCREASED BOUNDARY LAYER MOISTURE ACROSS OUR REGION...AND WILL SET THE STAGE FOR SCATTERED SHOWERS AND THUNDERSTORMS. ON SATURDAY...THE CUTOFF SHORTWAVE WILL ROTATE ACROSS THE UPPER GREAT LAKES WHILE ITS ASSOCIATED COLD FRONT WILL PUSH ACROSS THE OHIO VALLEY TOWARDS OUR FORECAST AREA. INCREASING LARGE SCALE ASCENT AND LOW LEVEL CONVERGENCE WILL BRING A GOOD LIKELIHOOD OF CONVECTION DURING THIS TIME. PRECIPITABLE WATER VALUES NEARING 2 INCHES WILL BRING THE POTENTIAL FOR LOCALIZED HEAVY RAINFALL. THERE WILL ALSO BE A RISK FOR SEVERE WEATHER WITH INCREASINGLY STRONG WIND FIELDS ALOFT. MODEL CONSENSUS IS THAT THE COLD FRONT WILL WORK THROUGH THE AREA SATURDAY NIGHT CONTINUING THE LIKELIHOOD OF CONVECTION. BEHIND THE FRONT THERE WILL LIKELY BE A BREAK IN THE CONVECTIVE POTENTIAL... BUT WE SHOULD SEE ACTIVITY REDEVELOP SUNDAY AS THE COLD UPPER AIR LOW WORKS ACROSS THE AREA. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... THE MEDIUM RANGE PERIOD LOOKS TO BEGIN RATHER UNSETTLED AS A BROAD UPPER LEVEL TROUGH AND ITS CLOSED 500 MB CIRCULATION/COLD POOL ALOFT WORKS THROUGH THE GREAT LAKES REGION. THERE WILL BE GOOD CHANCES FOR CONVECTION THROUGH TUESDAY. FOR WEDNESDAY AND THURSDAY...THE UPPER LEVEL TROUGH AXIS WILL MOVE DOWNSTREAM WITH SURFACE RIDGE BUILDING IN FROM THE MID ATLANTIC STATES/TENNESSEE VALLEY. THIS PERIOD WILL HAVE THE BEST CHANCES FOR AN EXTENDED PERIOD OF DRY WEATHER. TEMPERATURES THROUGH EARLY NEXT WEEK LOOK TO BE AT OR BELOW NORMAL BUT SHOULD BE WARMING TO ABOVE NORMAL LEVELS BY THURSDAY. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... CLOUDS LINGERING BEHIND THIS MORNING`S RAIN HAS KEPT THE AIR OVER NEW YORK STATE RELATIVELY STABLE...PRECLUDING THE DEVELOPMENT OF ANY AFTERNOON CONVECTION. THE LEFT OVER MOISTURE IS GENERATING BKN DECKS WITH CIGS RANGING FROM MVFR TO VFR. THE VISIBLE IMAGE DOES SHOW THE CLOUDS THINNING OUT ACROSS THE NIAGARA PENINSULA...HOWEVER. THEREFORE...WILL HAVE TO KEEP AN EYE ON THIS AREA FOR THE POTENTIAL OF ANY CONVECTION WHICH MAY ADVECT EAST INTO THE VCNTY OF KIAG LATER IN THE AFTERNOON. SOME CONVECTION IS ALSO POSSIBLE ACROSS THE SOUTHER TIER LATE THIS AFTERNOON. OTHERWISE...WILL HAVE TO MONITOR THE PROGRESS OF A COLD FRONT THAT STRETCHES FROM GEORGIAN BAY TO THE CENTRAL PLAINS. THIS BOUNDARY IS FORECAST TO MOVE SLOWLY TO THE EAST AND CROSS LAKE ONTARIO TONIGHT BEFORE STALLING OVER CENTRAL NEW YORK FRIDAY. A FEW SHOWERS OR THUNDERSTORMS MAY DEVELOP ACROSS THE AREA TONIGHT AS THE FRONT APPROACHES. MAINLY VFR CONDITIONS WILL DETERIORATE TO MVFR AS THE SURFACE TEMPERATURES COOL TOWARD THEIR DEWPOINTS. THE WEAKENING FRONT IS FORECAST TO STALL OVER SOUTHERN NEW YORK STATE FRIDAY. WITH MOIST AIR STILL IN PLACE ACROSS THE AREA DAYTIME HEATING WILL MAY STILL GENERATE A FEW -TSRA ALONG THE FRONT DURING THE AFTERNOON. THE BEST CHANCE FOR CONVECTION FRIDAY AFTERNOON WILL BE ACROSS THE SOUTHERN TIER AND UPPER GENESEE VALLEY. EXPECT MVFR (IFR ACROSS THE SOUTHERN TIER) CONDITIONS FRIDAY MORNING TO GRADUALLY IMPROVE TO VFR LATE FRIDAY MORNING INTO FRIDAY AFTERNOON. OUTLOOK... SATURDAY...VFR. CHC SHWRS. SUNDAY THROUGH TUESDAY...VFR/MVFR. CHC TSTMS. && .MARINE... WHILE THERE WILL BE THE RISK OF SCATTERED THUNDERSTORMS OVER LAKES ERIE AND ONTARIO TONIGHT...NO WIND BASED MARINE HEADLINES WILL BE NECESSARY THROUGH AT LEAST FRIDAY. AN AREA OF LOW PRESSURE OVER SOUTHERN ONTARIO WILL PASS BY TO THE NORTH OF THE LAKES THIS EVENING...WITH MODERATE TO FRESH SOUTHWESTERLIES BEING PRODUCED OVER LAKE ERIE AS A RESULT. MEANWHILE...GENTLE TO MODERATE BREEZES WILL BE FOUND ON LAKE ONTARIO. A RIDGE WILL THEN CROSS THE EASTERN LAKES TONIGHT AND FRIDAY...WITH LIGHT TO GENTLE BREEZES PREDOMINATING. UNSETTLED CONDITIONS ARE THEN EXPECTED ACROSS BOTH LAKES FOR THE WEEKEND AS THE POTENTIAL FOR THUNDERSTORMS WILL MARKEDLY INCREASE. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...TMA NEAR TERM...TJP SHORT TERM...TMA LONG TERM...TMA AVIATION...TJP MARINE...TMA ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 321 PM CDT THU JUN 26 2008 FORECAST FOCUS ON SEVERE WEATHER CHANCES FOR FRIDAY. NEAR-TERM...TONIGHT. DEALING WITH MAINLY CI BLOW OFF AT THE MOMENT. COMPLEX ACRS IA INTO MO SAPPING UP THE MOIST/INFLOW/INSTAB. ISODROSOTHERM ANALYSIS SHOWS A LITTLE BUBBLE OF DRIER AIR HAS WORKED INTO SRN WI WITH THE REAL GOOD JUICE OFF TO THE WEST. THINKING IS THAT REDEVELOPMENT WILL TAKE PLACE LATER TNGT TO OUR WEST WITH CHANCES INCREASING ACRS THE CWA LATER TNGT. FOR NOW WILL LEAN TOWARDS THE QPF TRENDS OF THE NAM/RUC AND NGM WHICH KEEPS US LARGELY RAIN FREE THRU 6Z. .SHORT TERM...KEY TO FRIDAY SEVERE TIMING AND PLACEMENT WILL BE DEPENDENT ON OVERNIGHT WARM AIR ADVECTION CONVECTION AND RESULTANT OUTFLOW BOUNDARIES. WILL LEAN TOWARD NAM FOR DETAILS AS SPURIOUS 500MB CONVECTIVE VORTICITY MAXIMA ON GFS AFFECTING LAYERS BELOW...MAKING IT AN OUTLIER. CWA IN FAVORED REGION TO THE LEFT OF STRONGEST 850 MB WINDS BETWEEN 18Z-00Z SAT. SUFFICIENT INSTABILITY WITH ML CAPES OF 1500-2000 J/KG...EVEN AFTER LOWERING SOMEWHAT GENEROUS SFC DEW POINTS. DEEP LAYER SHEAR OF 25 TO 30 KTS ENOUGH TO ORGANIZE STORMS. WILL LEAVE LIKELY WORDING FOR NOW...BUT ALL OF THE CWA SHOULD SEE SCATTERED TO WIDESPREAD CONVECTION FRIDAY AFTERNOON AND EVENING. AS FOR RAIN FROM THE STORMS IMPACTING SATURATED SOILS AND SWOLLEN RIVERS...PRECIPITABLE WATERS INCREASE TO 1.54 INCHES...BUT MESO- BETA ELEMENTS MOVING AT 15 TO 20 KNOTS DURING MOST FAVORED TIME. WILL RE-ISSUE ESF FOR NOW AS IT WILL TAKE ONLY 1/4 TO 1/2 INCH OF RAIN IN AN HOUR OR LESS TO CAUSE SOME STREET FLOODING PROBLEMS BUT NOT ENOUGH CLARITY TO TARGET ANY GIVEN AREA FOR A WATCH AT THIS TIME. UPPER LOW SETTLES IN OVER REGION FOR THE WEEKEND. SIMILAR TO LAST WEEK...500 MB TEMPERATURES IN THE -15C TO -18C RANGE WILL LEAD TO STEEP MID LVL LAPSE RATES AND ENOUGH INSTABILITY FOR ISOLATED AFTERNOON AND EARLY EVENING THUNDERSTORM DEVELOPMENT BOTH SATURDAY AND SUNDAY. POSSIBILITY AGAIN FOR SMALL HAIL AND GUSTY WINDS WITH INVERTED V SOUNDINGS. MONDAY...TIMING OF UPPER LOW EXITING WESTERN GREAT LAKES WILL BE KEY TO EARLY NEXT WEEK FORECAST. OPERATIONAL FORECASTS ALL TAKE UPPER LOW AND ASSOCIATED COLD POOL TO AROUND THE STRAITS OF MACKINAW BY 00Z MONDAY...AND OVER...OR NORTH OF... LAKE HURON BY 12Z MONDAY. WILL KEEP SLIGHT CHANCE FOR SUNDAY NIGHT AND HAVE DRY WITH RIDGING BUILDING INTO REGION FOR MONDAY INTO WEDNESDAY. .LONG TERM...QUIET WEATHER MONDAY THROUGH WEDNESDAY MORNING...WITH NEAR NORMAL TEMPERATURES. NORTHERLY SFC WIND TURNS NE ALONG THE LAKE...SO EARLY AFTERNOON HIGHS THEN FALLING TEMPS MONDAY. WEAK GRADIENT TUESDAY BRINGS SIMILAR TEMP SCENARIO. NEXT PRECIPITATION CHANCE COMES WED AFTERNOON/EVENING WITH WARM AIR ADVECTION REGIME SETTING UP AHEAD OF NEXT 500MB TROF. ML CAPES REACH 1000-1500 J/KG IN NW HALF OF ON FAVORED ECMWF BY 00Z SO WILL BRING CHANCES THERE IN THE AFTERNOON...AND CWA-WIDE WED NIGHT. SLOW MOVEMENT OF SFC TROF THRU REGION BRINGS POTENTIAL FOR A FEW ROUNDS OF SHOWERS AND STORMS INTO FRIDAY MORNING. && .AVIATION...VFR THROUGH PERIOD AS ANY FORCING MECHANISMS FOR THUNDERSTORMS REMAIN VERY SUBTLE UNDER WEAK FLOW. LLJ REMAINS PARKED UPSTREAM OF THE CWA AND EXPECT REGENERATING THUNDERSTORMS TO FIRE ACROSS NW IA/SW MN INTO TONIGHT. COULD SEE THOSE STORMS ROLL IN LATER TONIGHT...BUT THERE IS STILL UNCERTAINTY AS TO THAT EVOLUTION. HOWEVER WILL HINT AT SOME THUNDER IN THE TAFS LATER TNGT INTO FRI MORNING. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ SHORT/LONG TERM...09 AVIATION/MARINE...10 wi