AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1130 AM CDT THU AUG 3 2006 .DISCUSSION... UPDATED THE FORECAST TO LOWER CONVECTION CHANCES A BIT ACROSS THE NORTH AND JUST MINOR TWEAKS TO THE TEMPS/WINDS AND DEWPOINTS. MOSTLY CLOUDY AND STILL HUMID THIS AFTERNOON WITH ISOLATED SHOWERS AND THUNDERSTORMS FROM THE IL RIVER NW AND LIKELY CHANCES FROM I-72 SOUTH. HIGHS TO RANGE FROM THE LOWER 80S NW OF THE IL RIVER TO THE LOWER 90S IN SE IL NEAR LAWRENCEVILLE. CONVECTION WITH LOCALLY HEAVY RAINS MOVED NE OUT OF EASTERN IL INTO INDIANA LATE THIS MORNING. 11 AM SURFACE MAP SHOWS 1009 MB LOW PRESSURE OVER SW LOWER MI WITH A COLD FRONT EXTENDING SW ACROSS NW IL NEAR THE IL RIVER AND INTO CENTRAL MO. 1019 MB WEAK HIGH PRESSURE WAS OVER CENTRAL NEBRASKA. ALOFT A 594 DM 500 MB SUBTROPICAL RIDGE WAS ACROSS THE GULF COAST STATES AND TN VALLEY THAT WAS RESPONSIBLE FOR OUR 5 DAY HEAT WAVE. WEAK UPPER LEVEL TROF WAS OVER THE MIDWEST WITH AN MCS OVER CENTRAL INDIANA. RUC AND NAM/WRF MOVE COLD FRONT SE FROM THE IL RIVER INTO SE IL THIS AFTERNOON...REACHING LAWRENCEVILLE BY SUNSET. THIS FRONT HAS BEEN MOVING SLOWER THAN MODELS ADVERTISED EARLIER. MODELS NOT SHOWING AS MUCH QPF OVER CENTRAL/SE IL THIS AFTERNOON AS SHOWER EARLIER RUNS. HELD ONTO LIKELY CHANCES FROM I-72 SOUTH WHILE JUST 20 PERCENT CHANCE FROM THE IL RIVER NW. SPC HAS SLIGHT RISK OF SEVERE OVER SE IL SE OF A DANVILLE TO EFFINGHAM LINE FOR 15% CHANCE OF DAMAGING WINDS AND 5% CHANCE OF LARGE HAIL AND ONLY 2% CHANCE OF A TORNADO. SE IL WAS WORKED OVER BY CONVECTION THIS MORNING BUT SHOULD SEE SUN BREAK THROUGH THE CLOUDS AND ALLOW HEATING/DESTABLIZATION AHEAD OF COLD FRONT. 850 MB TEMPS AROUND 20C SLIP TO 16-17C FROM PEORIA NORTH AND STAY AROUND 20C OVER SE IL THIS AFTERNOON. SO HIGHS RANGING FROM LOWER 80S NORTH OF PEORIA AND LOWER 90S OVER SE IL BY LAWRENCEVILLE WHERE HEAT INDEX APPROACHED 100F. STILL HUMID WITH DEWPOINTS IN THE LOWER 70S...THOUGH SLIPPING BETWEEN 65 AND 70F NW OF PEORIA BEHIND THE COLD FRONT. .PREV DISCUSSION... PRIMARY CONCERNS WITH THIS PACKAGE WILL BE THE TIMING AND PLACEMENT OF PRECIP/CONVECTION THROUGH DAY ONE. FORECAST BECOMES QUIETER... AND MILDER BEYOND THAT. SHORT TERM...TODAY THROUGH SUNDAY... FORWARD PROPAGATING MCS OVER EASTERN IA/WESTERN ILLINOIS IS FOLLOWING CORFIDI VECTORS NICELY THIS MORNING. THIS HAS BLOWN UP OUT AHEAD OF A VIGOROUS SHORTWAVE WHICH IS MOVING ACROSS THE MIDWEST. MORE CONVECTION HAS FIRED UP JUST AHEAD OF THE SLOW MOVING COLD FRONT ACROSS THE I-74 CORRIDOR. MAIN PROBLEM IS THAT MODEL GUIDANCE HAS PRETTY MUCH DROPPED THE BALL RIGHT FROM THE INITIALIZATION PERIOD WITH THIS MCS... BOTH NAM AND GFS ALIKE. RUC ANALYZED THE SITUATION WELL ENOUGH... BUT MYSTERIOUSLY DROPPED OUR MCS SHARPLY SOUTHEASTWARD. BASED ON TRENDS AND OBSERVATIONS... CURRENT MCS SHOULD CONTINUE EASTWARD INTO THE FAR NW PORTION OF THE CWA EARLY THIS MORNING... MAINLY BEFORE 12Z... AND BEGIN TO DECAY ONCE IT GETS EAST OF WHERE THE LLJ IS MORE PRONOUNCED. SOUTHERN EDGE OF THE MCS APPEARS TO BE DECAYING THE MOST... AS IT IS FARTHER REMOVED FROM STRONGER LOW LEVEL BAROCLINICITY. BASICALLY... IT SHOULD HOLD TOGETHER BEST NORTH OF WHERE CONVECTION HAS BEEN FIRING UP ALONG THE COLD FRONT. CONVECTION SHOULD CONTINUE TO SHIFT SOUTHWARD THROUGH THE LATE MORNING AND AFTERNOON HOURS... AHEAD OF THE COLD FRONT. MAIN CONCERNS WILL BE FOR HEAVY RAIN POTENTIAL BETWEEN THE I-74 AND I-72 CORRIDORS WHERE PRECIP MAY TEND TO TRAIN DUE TO PARALLEL NATURE OF THE UPPER AND LOW LEVEL FLOW. FFG VALUES ARE RATHER HIGH... BUT WITH PWAT VALUES FORECAST TO RISE ABOVE 2 INCHES THIS AFTERNOON... IT WILL NOT TAKE MUCH TRAINING TO CAUSE LOCALIZED PROBLEMS. STILL THINK THE THREAT WILL BE LOCALIZED ENOUGH... GIVEN THE ABOVE REASONS PLUS LACK OF RECENT RAINS... THAT NO HEADLINES ARE NEEDED AT THIS POINT. SEVERE WEATHER THREAT WILL CONTINUE TO BE LIMITED THIS MORNING BY NOCTURNAL INVERSION KEEPING STRONGER WINDS ALOFT... EXCEPT IN ISOLATED AREAS... AND HIGH FREEZING LEVELS REDUCING THE THREAT FOR LARGE HAIL. BEST BET FOR SVR WILL BE IN THE FAR SOUTHEAST THIS AFTERNOON AND EARLY THIS EVENING... WHERE LACK OF CLOUD COVER WILL PROMOTE RAPID SFC HEATING THIS AFTERNOON... WITH TEMPS APPROACHING THE LOWER 90S. THIS WILL ALLOW FOR PLENTY OF INSTABILITY... ALLOWING SFC BASED CONVECTION TO FIRE UP ALONG EITHER THE COLD FRONT ITSELF... OR ANY NUMBER OF LEFTOVER OUTFLOW BOUNDARIES PRECEDING IT. FRONT IS STILL EXPECTED TO LINGER IN THE FAR SOUTHEAST THROUGH TOMORROW AFTERNOON... WARRANTING CHANCE POPS SOUTH OF I-70 THROUGH TOMORROW. LONG TERM...MONDAY THROUGH WEDNESDAY... GUIDANCE STILL IN VERY GOOD AGREEMENT WITH THE MEAN UPPER LEVEL PATTERN THROUGH THE PERIOD. THIS SUGGESTS EVENTUAL RETROGRESSION OF SUBTROPICAL HIGH BACK OVER THE PLAINS... WHERE IT BELONGS... AND THE SETTING UP OF A NORTHWEST FLOW PATTERN OVER THE MIDWEST BY EARLY NEXT WEEK. NEXT SHORTWAVE LOOKS TO MOVE ACROSS THE NORTHERN GREAT LAKES IN THE MON-TUE TIMEFRAME... AND THE GFS AND ENSEMBLES CONTINUE TO BE RATHER WOUND UP WITH THIS SYSTEM. STILL... THIS SUPPORTS CHANCE POPS MONDAY AND TUESDAY AFTERNOON... WITH THE POSSIBILITY OF A WET PERIOD SETTING UP TOWARDS THE BEGINNING AND MIDDLE OF NEXT WEEK WITH A STATIONARY FRONT SETUP ACROSS THE AREA... AND NORTHWEST FLOW ALOFT. && ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ HUETTL/HARDIMAN il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 740 AM CDT THU AUG 3 2006 .DISCUSSION... JUST SENT A QUICK UPDATE TO REMOVE THE EARLY MORNING WORDING IN THE FORECAST. FRONT APPEARS TO HAVE DROPPED SOUTH INTO PARTS OF CENTRAL ILLINOIS. HOWEVER...THIS COULD JUST BE OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION. WILL HAVE TO WAIT FOR A FEW MORE HOURS AND SEE HOW THE SFC OBSERVATIONS RECOVER WITH THE CURRENT LIGHT SURFACE WINDS. AT ANY RATE...EVEN IF THE MAIN FRONT IS STILL NORTH OF CENTRAL ILLINOIS...THE ACTIVE FRONT WILL LIKELY BE ACROSS SOUTHEASTERN ILLINOIS FOR THIS AFTERNOON. .PREV DISCUSSION... PRIMARY CONCERNS WITH THIS PACKAGE WILL BE THE TIMING AND PLACEMENT OF PRECIP/CONVECTION THROUGH DAY ONE. FORECAST BECOMES QUIETER... AND MILDER BEYOND THAT. SHORT TERM...TODAY THROUGH SUNDAY... FORWARD PROPAGATING MCS OVER EASTERN IA/WESTERN ILLINOIS IS FOLLOWING CORFIDI VECTORS NICELY THIS MORNING. THIS HAS BLOWN UP OUT AHEAD OF A VIGOROUS SHORTWAVE WHICH IS MOVING ACROSS THE MIDWEST. MORE CONVECTION HAS FIRED UP JUST AHEAD OF THE SLOW MOVING COLD FRONT ACROSS THE I-74 CORRIDOR. MAIN PROBLEM IS THAT MODEL GUIDANCE HAS PRETTY MUCH DROPPED THE BALL RIGHT FROM THE INITIALIZATION PERIOD WITH THIS MCS... BOTH NAM AND GFS ALIKE. RUC ANALYZED THE SITUATION WELL ENOUGH... BUT MYSTERIOUSLY DROPPED OUR MCS SHARPLY SOUTHEASTWARD. BASED ON TRENDS AND OBSERVATIONS... CURRENT MCS SHOULD CONTINUE EASTWARD INTO THE FAR NW PORTION OF THE CWA EARLY THIS MORNING... MAINLY BEFORE 12Z... AND BEGIN TO DECAY ONCE IT GETS EAST OF WHERE THE LLJ IS MORE PRONOUNCED. SOUTHERN EDGE OF THE MCS APPEARS TO BE DECAYING THE MOST... AS IT IS FARTHER REMOVED FROM STRONGER LOW LEVEL BAROCLINICITY. BASICALLY... IT SHOULD HOLD TOGETHER BEST NORTH OF WHERE CONVECTION HAS BEEN FIRING UP ALONG THE COLD FRONT. CONVECTION SHOULD CONTINUE TO SHIFT SOUTHWARD THROUGH THE LATE MORNING AND AFTERNOON HOURS... AHEAD OF THE COLD FRONT. MAIN CONCERNS WILL BE FOR HEAVY RAIN POTENTIAL BETWEEN THE I-74 AND I-72 CORRIDORS WHERE PRECIP MAY TEND TO TRAIN DUE TO PARALLEL NATURE OF THE UPPER AND LOW LEVEL FLOW. FFG VALUES ARE RATHER HIGH... BUT WITH PWAT VALUES FORECAST TO RISE ABOVE 2 INCHES THIS AFTERNOON... IT WILL NOT TAKE MUCH TRAINING TO CAUSE LOCALIZED PROBLEMS. STILL THINK THE THREAT WILL BE LOCALIZED ENOUGH... GIVEN THE ABOVE REASONS PLUS LACK OF RECENT RAINS... THAT NO HEADLINES ARE NEEDED AT THIS POINT. SEVERE WEATHER THREAT WILL CONTINUE TO BE LIMITED THIS MORNING BY NOCTURNAL INVERSION KEEPING STRONGER WINDS ALOFT... EXCEPT IN ISOLATED AREAS... AND HIGH FREEZING LEVELS REDUCING THE THREAT FOR LARGE HAIL. BEST BET FOR SVR WILL BE IN THE FAR SOUTHEAST THIS AFTERNOON AND EARLY THIS EVENING... WHERE LACK OF CLOUD COVER WILL PROMOTE RAPID SFC HEATING THIS AFTERNOON... WITH TEMPS APPROACHING THE LOWER 90S. THIS WILL ALLOW FOR PLENTY OF INSTABILITY... ALLOWING SFC BASED CONVECTION TO FIRE UP ALONG EITHER THE COLD FRONT ITSELF... OR ANY NUMBER OF LEFTOVER OUTFLOW BOUNDARIES PRECEDING IT. FRONT IS STILL EXPECTED TO LINGER IN THE FAR SOUTHEAST THROUGH TOMORROW AFTERNOON... WARRANTING CHANCE POPS SOUTH OF I-70 THROUGH TOMORROW. LONG TERM...MONDAY THROUGH WEDNESDAY... GUIDANCE STILL IN VERY GOOD AGREEMENT WITH THE MEAN UPPER LEVEL PATTERN THROUGH THE PERIOD. THIS SUGGESTS EVENTUAL RETROGRESSION OF SUBTROPICAL HIGH BACK OVER THE PLAINS... WHERE IT BELONGS... AND THE SETTING UP OF A NORTHWEST FLOW PATTERN OVER THE MIDWEST BY EARLY NEXT WEEK. NEXT SHORTWAVE LOOKS TO MOVE ACROSS THE NORTHERN GREAT LAKES IN THE MON-TUE TIMEFRAME... AND THE GFS AND ENSEMBLES CONTINUE TO BE RATHER WOUND UP WITH THIS SYSTEM. STILL... THIS SUPPORTS CHANCE POPS MONDAY AND TUESDAY AFTERNOON... WITH THE POSSIBILITY OF A WET PERIOD SETTING UP TOWARDS THE BEGINNING AND MIDDLE OF NEXT WEEK WITH A STATIONARY FRONT SETUP ACROSS THE AREA... AND NORTHWEST FLOW ALOFT. && ILX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AUTEN/HARDIMAN il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 110 PM EDT THU AUG 3 2006 .UPDATE... UPDATE COMING SHORTLY WITH SVR TSTORM WATCH NUMBER 683 JUST GRAZING OUR EXTREME SOUTHEAST 2 COUNTIES. CLUSTER OF THUNDERSTORMS OVER CENTRAL INDIANA SHOULD BEGIN TO STRENGTHEN AS THEY MOVE INTO OHIO AND INTO A MODERATELY UNSTABLE AIRMASS. THAT SAID...OUR CWA IS DOMINATED BY CLOUD COVER WHICH HAS SIGNIFICANTLY INHIBITED HEATING. GIVEN LACK OF INSTABILITY...EXPECT BULK OF SEVERE WEATHER THREAT TO REMAIN SOUTHEAST OF THE CWA. ELSEWHERE ACROSS THE CWA PREVIOUS RAIN AND EXTENSIVE CLOUD COVER CONTINUES TO LIMIT SOLAR INSOLATION. AS SUSPECTED YESTERDAY...COLD FRONT IS MUCH SLOWER THAN OPERATIONAL GUIDANCE...NOW JUST ENTERING THE NW CORNER OF THE CWA. HOWEVER...UNLESS SUNSHINE IS ABLE TO BREAK OUT IN THE PRE-FRONTAL AIRMASS THE CHANCE OF ADDITIONAL STORMS ALONG THE FRONT IS NIL. && .AVIATION... SEE UPDATE DISCUSSION ABOVE FOR THOUGHTS ON CONVECTIVE POTENTIAL. SHRA EXITING KFWA AT 17Z WITH JUST A FEW SCT SHRA NW OF THE KSBN TERMINAL WITHIN ZONE OF WEAK LIFT JUST ON THE COLD SIDE OF THE SURFACE FRONT. DECENT AMOUNT OF MVFR STRATUS JUST BEHIND THE SURFACE FRONT WILL CONTINUE TO IMPACT KSBN TERMINAL PERIODICALLY THROUGH THIS EVENING. A PERIOD OF MVFR MAY ALSO AFFECT KFWA THIS EVENING FOR SEVERAL HOURS FOLLOWING FROPA. LATER TONIGHT DRIER AIR AND SUBSIDENCE BUILDS IN FROM NW TO SE ACROSS THE REGION WITH CLEARING SKIES. BOUNDARY LAYER WINDS WILL LIKELY REMAIN STRONG ENOUGH TO PRECLUDE ANY BR FORMATION OVERNIGHT. && .PREV DISCUSSION... SHORT TERM... TODAY AND TONIGHT. THE SHORT TERM FORECAST IS A DIFFICULT ONE THIS MORNING. AT 07Z...SFC ANALYSIS DEPICTED A FRONTAL BOUNDARY FROM SRN ONTARIO...SOUTHWEST INTO SRN MICHIGAN...THEN INTO ILLINOIS...NRN MISSOURI AND NRN KANSAS. THIS FRONT WILL SLOWLY SAG THROUGH THE FCST AREA TODAY AND TONIGHT. OPERATIONAL 00Z NAM-WRF AND GFS DO NOT SEEM TO HAVE A GOOD HANDLE ON THE CURRENT FCST SITUATION. THUS...HAVE RELIED ON THE LATEST RUC40 MODEL AND CURRENT SATELLITE...RADAR AND WATER VAPOR IMAGERY. THIS MORNING/S CONVECTION FROM THE MIDDLE MS RIVER VLY INTO OUR REGION HAS RESULTED IN SEVERAL OUTFLOW BOUNDARIES. ONE OF PARTICULAR INTEREST IS THE OUTFLOW BOUNDARY/CONVECTION OCCURRING ACRS W CNTRL ILLINOIS THIS MORNING. THIS FEATURE WAS MOVING FAIRLY FAST...ABOUT 40 TO 50 MPH...TO THE NORTHEAST. THIS FEATURE...IN COMBINATION WITH LOW LVL WAA/LOW LVL JET...WILL RESULT IN AN INCREASE OF SHOWERS AND THUNDERSTORM ACRS THE REGION LATER THIS MORNING. ALSO...THIS WILL DEFINITELY HAVE AN IMPACT ON HOW FAR SOUTH THE FRONT WILL PUSH ACRS THE FCST AREA TODAY. TO ADD INSULT TO INJURY...WATER VAPOR IMAGERY DEPICTED A WELL DEFINED S/WV ACRS NE KS/NW MISSOURI. THIS SYSTEM...AS SEEN FROM THE LATEST RUC40 MODEL IS FORECAST TO PUSH EAST INTO NW INDIANA BY AROUND 18Z...PROVIDING UPR LVL LIFT AS IT MOVES INTO OUR REGION. AS A RESULT OF ALL THESE FACTORS...HAVE EMPLOYED LIKELY POPS ACRS THE ENTIRE REGION TODAY. THE AIRMASS WILL BE QUITE MOIST AS PRECIPITABLE WATER VALUES ARE EXPECTED TO BE AROUND 2 INCHES. THUS...WILL MENTION HEAVY RAIN IN THE ZONES. HAVE DECIDED NOT TO ISSUE A FLOOD WATCH ATTM IN COLLABORATION WITH OTHER OFFICES (IND/ILN) AS CURRENT 1 HOUR FFG VALUES ARE MAINLY IN THE 2 TO 2.3 INCH RANGE. HOWEVER...THERE WILL BE SOME LOCALIZED FLOODING WITH THUNDERSTORMS AND SOME URBAN AND SMALL STREAM FLOOD ADVISORIES MAY BE ISSUED. AS FOR HIGH TEMPS TODAY...IT WILL BE A TOUGH CALL GIVEN WARM START...AND HIGH PROBABILITY OF SHOWERS/THUNDERSTORMS. HAVE TWEAKED PREVIOUS FORECAST VALUES SLIGHTLY...RANGING FROM THE LOWER 80S NORTHWEST TO THE UPPER 80S SOUTH/SOUTHEAST. FOR TONIGHT...ONCE AFOREMENTIONED S/WV RIPPLES BY TO THE EAST...THE FRONTAL BOUNDARY SHOULD HAVE A MORE PUSH SOUTHWARD OUT OF OUR AREA. WILL MAINTAIN CHC POPS IN THE SERN TWO THIRDS OF THE CWFA...BUT THIS MAY HAVE TO BE ADJUSTED BASED ON TIMING OF MENTIONED SYSTEMS. OVERNIGHT LOWS SHOULD DROP INTO THE LOWER AND MID 60S. LONG TERM.... FRIDAY THROUGH WEDNESDAY...KEPT THE PERIOD DRY EXCEPT FOR A CHANCE OF STORMS MONDAY. WEAK HIGH PRESSURE WILL BUILD IN FOR THE WEEKEND...ALTHOUGH NOT MUCH COOL AIR WILL BE ABLE TO MAKE IT INTO THE AREA. THE NEW 03/00Z MEX FOLLOWED THE 02/00Z KEEPING HIGHS ABOVE NORMAL THIS WEEKEND. THIS WARM PATTERN APPEARS ON TRACK WITH 850 MB TEMPS AT OR ABOVE 16C. TIMING OF COOL FRONT MONDAY ALONG WITH A CHANCE OF STORMS STILL APPEARS ON TRACK. THE MAIN UPPER LEVEL PATTERN WILL SHIFT AS AN UPPER RIDGE BUILDS OVER THE NORTHERN PLAINS. THE FORECAST AREA SHOULD BE FAR ENOUGH DOWNSTREAM FROM THIS RIDGE TO ALLOW SOME COOLER AIR TO ADVECT INTO THE AREA TUESDAY AND WEDNESDAY. THIS COOLER PATTERN IS REFLECTED WELL IN THE NEW MEX MOS WITH TEMPERATURES ACTUALLY BELOW NORMAL TUESDAY AND WEDNESDAY. HAVE ADJUSTED TEMPS DOWN GIVEN THE HIGH CORRELATION WITH THE ANALOGS OF GFS RUNS...GFS ENSEMBLE ANALOGS AND THE CANADIAN ANALOGS THAT MATCH THIS PATTERN. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE/AVIATION...HITCHCOCK SHORT TERM...HICKMAN LONG TERM...SKIPPER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 236 PM MDT THU AUG 3 2006 .DISCUSSION...FORECAST CONCERNS CONTINUE TO BE TEMPERATURES AND PRECIPITATION TONIGHT AND FRIDAY. IN THE SHORT TERM...THERE ARE TWO CONVECTIVE FEATURES TO MONITOR. THE FIRST IS LOW TOPPED CONVECTION ACROSS WASHINGTON/YUMA COUNTIES COLORADO THAT FORMED IN AN INSTABILITY AXIS. THE CONVECTION HAS BEEN VERY SLOW TO MOVE EAST. MODELS...INCLUDING THE RUC...ARE NOT SUPPORTIVE OF ADVECTING THIS ACTIVITY ACROSS KANSAS. OTHER CONVECTION ALONG THE FRONT RANGE IS ALSO NOT EXPECTED TO MOVE EAST. THE OTHER AREA TO MONITOR IS ACROSS NORTHEAST NEW MEXICO/TEXAS PANHANDLE. GFS AND WRF SPREAD THIS AREA OF PRECIPITATION INTO SOUTHERN KANSAS LATE TONIGHT...AND INTO NORTHWEST KANSAS BY FRIDAY MORNING. WATER VAPOR IMAGERY SHOWS SHOWS CYCLONIC FLOW NEAR EL PASO. APPEARS THAT SOME DYNAMICS WITH THAT FEATURE WILL BE ADVECTED NORTHEAST INTO THE CENTRAL PLAINS LATER TONIGHT. THEREFORE...LIKE THE IDEA OF PREVIOUS FORECASTS OF SOME CONVECTION LATE TONIGHT AS NEXT WAVE MOVES OVER THE AREA. THE PRESENCE OF THE LOW LEVEL JET WILL ALSO AID IN CONVECTIVE DEVELOPMENT. LINGERING SHOWERS WILL CONTINUE FRIDAY MORNING...MAINLY OVER THE EASTERN HALF OF THE FORECAST AREA. THEN 500 MB RIDGE WILL SLOWLY REBUILD OVER THE AREA. CAPES DURING THE AFTERNOON WILL BE AROUND 1000 J/KG. EXPECT WEAK WAVES TO MOVE ACROSS THE AREA...SO WILL MENTION SOME LATE AFTERNOON/CONVECTION...BUT POPS WILL BE LOW. WEAK SURFACE BOUNDARY WILL MOVE THROUGH THE AREA SATURDAY AFTERNOON/EVENING...LEADING TO ANOTHER CHANCE OF CONVECTION. WILL LIKELY HAVE SOME BOUNDARIES IN THE EXTENDED PERIODS...BUT CONFIDENCE IS NOT HIGH...SO WILL KEEP THE FORECAST DRY. 850 MB TEMPERATURES WARM A FEW DEGREES FRIDAY AND AGAIN SATURDAY BEFORE COOL FRONT KNOCKS TEMPERATURES BACK A FEW DEGREES SUNDAY. HAVE ACCEPTED THIS SCENARIO BASED ON GFS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ MENTZER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 308 PM EDT THU AUG 3 2006 .SYNOPSIS.... A WEAK LOW PRESSURE SYSTEM WILL MOVE EAST ALONG A STATIONARY FRONT ACROSS THE GULF OF MAINE TONIGHT AND EARLY FRIDAY. A SECOND COLD FRONT WILL SLIDE THROUGH NORTHERN AND EASTERN MAINE FRIDAY EVENING. COOLER AND MUCH DRIER CONDITIONS WILL PREVAIL ACROSS THE REGION OVER THE WEEKEND AS HIGH PRESSURE BUILDS IN FROM SOUTHERN CANADA. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... MAIN FOCUS THIS PACKAGE WILL BE HOW MUCH RAFL ACROSS DOWNEAST & COASTAL AREAS TONIGHT W/SFC WAVE MOVING THROUGH THE COASTAL WATERS TONIGHT & CONVECTION FOR FRIDAY. USED THE RUC TO START THINGS OUT TONIGHT AS IT APPEARS TO BE HANDLING THINGS THE BEST PER THE RADAR & SATL IMAGERY & THEN TOOK A MIDDLE OF THE ROAD APCH LATER TONIGHT INTO FRIDAY WEIGHTING THE GFS A LITTLE BIT MORE THAN THE WRF FOR POP & QPF GRIDS. SKY GRIDS ARE A REFLECTION OF THE WRF TONIGHT & FRIDAY NIGHT & MORE TOWARD THE GFS DURING THE DAYTIME HOURS. SFC WAVE WILL PASS THROUGH THE GULF OF MAINE BY EARLY FRIDAY MORNING W/HIGHEST POPS & QPF SITUATED ACROSS THE WATERS. WENT W/CHC POPS ACROSS DOWNEAST & COASTAL AREAS TO PLAY FOR THIS FEATURE AFT COORDINATION W/GYX. GFS LOOKS TOO HIGH ON QPF W/THIS WEAK WAVE. TEMPERATURES TONIGHT AS REFLECTION OF THE MAV. FRONTAL ACROSS CANADA IS PROGGED BY THE MODELS TO DROP ACROSS NRN & ERN MAINE DURING THE DAY ON FRIDAY. LEANED W/40-50% POPS FROM NERN ME BACK INTO THE CNTL HIGHLANDS & STARTED DRYING THINGS OUT FURTHER S. INSTABILITY PARAMETERS FAIRLY DECENT W/CAPES RUNNING 700 TO APPROXIMATELY 1000 J/KG BY LATE AFTERNOON. LAPSE RATES APCH 6.0 TO 6.5 C/KM. LLVL WARMING COUPLED W/SOME MID LVL COOLING WILL ALLOW FOR THE POSSIBILITY OF CONVECTION. THINKING MORE IN THE LINE OF PULSE CONVECTION ACROSS NRN & ERN AREAS. FRONT WILL CLEAR THE CWA BY FRIDAY NIGHT W/COOLER AIR POISED TO ARRIVE BY SATURDAY MORNING. TOOK A BLEND OF THE MAV/MET FOR FRIDAY/S DAYTIME TEMPS W/SOME ADJUSTMENTS ON THE UPWARD DUE TO INSOLATION EARLY ON. DRY & COOLER DAY ON SATURDAY AS SFC HIGH PRES MOVES ACROSS THE CWA. NNW WINDS WILL PICK BEHIND THE FRONT AS WELL ADDING A CHILL TO THE AIR. TOOK THE PREV MAX TEMP GRIDS FOR SATURDAY & ADJUSTED SLIGHTLY UPWARD MAINLY ACROSS CNTL & DOWENAST AREAS. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE WILL MOVE EAST OF THE REGION SATURDAY NIGHT...PRODUCING PARTLY CLOUDY SKIES. A WARM FRONT WILL LIFT ACROSS THE REGION SUNDAY/SUNDAY NIGHT BRINGING A CHANCE OF SHOWERS/THUNDERSTORMS. A COLD FRONT CROSSING THE FORECAST AREA MONDAY/MONDAY NIGHT WILL KEEP THE CHANCE OF SHOWERS/THUNDERSTORMS ACROSS THE REGION. HIGH PRESSURE SHOULD THEN BUILD ACROSS THE REGION TUESDAY THROUGH THURSDAY. TEMPERATURES WILL GENERALLY REMAIN AT NEAR NORMAL LEVELS TUESDAY THROUGH THURSDAY. && .AVIATION... EXPECT VFR CONDITIONS FOR THE NEXT 24 HOURS WITH THE POSSIBILITY OF SOME SCT SHRA/TSRA PRODUCING MVFR CONDITIONS IN THE AFTERNOON TOMORROW. && .MARINE... SHORT TERM:NO HEADLINES THIS RUN AS WAVES RUNNING NO MORE THAN 2 FT. PATCHY FOG TO PERSIST TONIGHT INTO EARLY FRI. FOLLOWED PREV GRIDS PRETTY CLOSE W/AN ADJSUTMENT FOR SATURDAY AS THE FRONT SLIDES ACROSS THE WATERS. THIS ADJUSTMENT WAS MAINLY FOR THE WINDS TO BRING THEM UP SLIGHTLY AS NNW GRADIENT TIGHTENS SOME EARLY ON & THEN RELAXES. LONG TERM: WINDS/SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS SATURDAY NIGHT THROUGH TUESDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ SHORT TERM/MARINE...HEWITT LONG TERM/MARINE...NORCROSS AVIATION...WEITLICH me AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CARIBOU ME 1049 AM EDT THU AUG 3 2006 .SYNOPSIS.... WEAK LOW PRESSURE SYSTEMS WILL MOVE EAST ALONG A STATIONARY FRONT ACROSS THE GULF OF MAINE TODAY AND TONIGHT BRINGING CLOUDINESS AND SHOWERS TO MAINLY DOWNEAST AREAS. HIGH PRESSURE RIDGING TOWARD THE AREA FROM THE GREAT LAKES SHOULD BRING CLEARING EVEN TO DOWNEAST MAINE BY FRIDAY AFTERNOON. A SECONDARY COLD FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO NORTHERN MAINE FRIDAY EVENING. THEN EXPECT FAIR...COOLER AND MUCH DRIER CONDITIONS TO PREVAIL ACROSS THE REGION OVER THE WEEKEND. && .UPDATE/REST OF TODAY/... UPDATED GRIDS & ZFP TO ADD MENTION OF SCTD SHOWERS & ISOLD TSTMS THIS AFTERNOON BASED ON LATEST RUC & WRF. SHEARED VORTICITY MOVING ACROSS THE REGION. KEPT FAR NRN & NWRN AREAS DRY W/STABLE AIRMASS IN PLACE. BEST LIFT FOR ANY ACTION LOOKS TO BE GEARED FROM HUL-MLT DOWN INTO CNTL HIGHLANDS. SHIFTED CLOUD SHIELD FURTHER S BASED ON LATEST SATL IMAGERY. NO OTHER CHGS WERE MADE. && .MARINE... KEPT PATCHY FOG IN THERE THROUGH THE AFTERNOON. VSBYS DOWN BLO 2 NM. I DID SHOW IMPROVING TRENDS THIS AFTERNOON W/VSBYS GOING TO 3 NM. && .PREVIOUS DISCUSSION... .SHORT TERM /TODAY THROUGH FRIDAY/... BOTH THE GFS AND WRF HAVE A PRETTY GOOD HANDLE WITH REMNANTS OF THE MCS MOVING OVR CNTRL AND SRN PTNS OF THE FA THIS MORN. STARTED POPS CATEGORICAL IN GRIDS...BUT FORMATTERS WENT WITH LIKELY POP WORDING WITH SHWRS THIS MORN...WHICH IS NOT A BAD FIT BASED ON THE SPEED OF MOVEMENT INDICATED BY THE RADAR. RNFL ERLY THIS MORN HAS BEEN FAIRLY HVY ACROSS XTRM WRN PTNS OF DOWNEAST MAINE...BUT RNFL RATES SHOULD TREND DOWNWARD FOR LOCATIONS FURTHER E ACROSS DOWNEAST MAINE OVR THE REST OF THE MORN AS THE MCS CONTS TO WEAKEN...BASED ON IR SAT CLD TOP WARMING TRENDS. AFTERWARDS...SCT SHWRS WILL STILL BE POSSIBLE THIS AFT ACROSS DOWNEAST ME GIVEN THE RELATIVELY CLOSE PROXIMITY OF THE STATIONARY FRONT AS SKIES BECOME PTLY SUNNY ACROSS THE NRN TWO THIRDS OF THE FA. GIVEN LIMITED POTENTIAL OF SUNSHINE AND SFC BASED CAPE...ONLY WENT ISOLD TSTMS WITH THIS MORN'S DEPARTING MCS AND WITH ANY AFT SHWR ACTIVITY. DAY SHIFT WILL NEED TO MONITOR TEMPS AND SUNSHINE ACROSS THIS AREA IN THE UNLIKELY EVENT MORE SUNSHINE THEN ANTICIPATED RESULTS IN MORE CONVECTIVE ACTIVITY. OTHERWISE...FOLLOWING ONE MORE LOW PRES SYSTEM MOVES E ACROSS THE STATIONARY FRONT IN THE GULF OF MAINE LATE TNGT WHICH WILL BRING ANOTHER ROUND OF SHWRS TO MSLY DOWNEAST MAINE ERLY FRI MORN...THE FRONT SHOULD BEGIN MOVING SWRD...ALLOWING PARTIAL CLRG AND DRIER CONDITIONS TO MOVE SWRD INTO DOWNEAST ME BY FRI AFT. MOST FCST GRIDS A BLEND OF GFS AND WRF...WITH THE GFS WEIGHTED A LITTLE MORE AFT THE FIRST 18 HRS OR SO. HI/LOW TEMPS TDY THRU FRI MODIFIED USING BLENDED MOS AND GFS ENS TEMPS. .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... A WEAK FRONT IS EXPECTED TO MOVE THRU THE FORECAST AREA FRIDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST BEHIND THE FRONT SATURDAY THEN CREST OVER NEW ENGLAND SATURDAY NIGHT. HAVE GENERATED GRIDS USING A COMBINATION OF THE GFS AND NAM. A 50/50 MODEL BLEND FOR QPF AND SKY WAS USED. FOR TEMPERATURE...DEW POINT...WIND AND POPS A MAV/MET COMBINATIONS WAS USED. && .AVIATION... MAINLY VFR...XCPT PERHAPS MVFR AT TIMES THIS MORN WITH SHWRS AND WITH PATCHY FOG LATE TNGT AT KBGR AND KHUL. && .MARINE... SHORT TERM: LGT WINDS AND LOW WVS WITH NO HEADLINES ANTICIPATED THRU FRI. LONG TERM: WITH LIGHT WINDS EXPECTED THROUGH THIS PERIOD HAVE CREATED WIND GRIDS WITH THE NAM12. THE WAVE GRIDS HAVE BEEN INITIALIZED WITH THE WNA WAVE WATCH III. SPECTRAL ANALYSIS INDICATES 1 TO 2 FEET BACK GROUND SWELL THROUGH THIS PERIOD...SO WITH LIGHT WINDS EXPECTED WILL KEEP COMBINED SEAS AT 2 FEET OR LESS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ UPDATE...HEWITT SHORT TERM/MARINE...MIGNONE LONG TERM/MARINE...VJN AVIATION...WEITLICH me AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE MARQUETTE MI 955 PM EDT THU AUG 3 2006 .DISCUSSION... THE MAIN CONCERN WITH THIS UPDATE FORECAST PACKAGE IS THE OVERNIGHT LOW TEMPERATURES. WATER VAPOR IMAGERY AND RUC SHOWING A WEAK SHORTWAVE OVER NORTHERN WISCONSIN...A WEAK RIDGE OVER WESTERN MANITOBA...AND A TROUGH OVER THE PACIFIC NORTHWEST. SURFACE ANALYSIS INDICATES A COLD FRONT STRETCHING FROM A LOW OVER THE SOUTHERN TIP OF JAMES BAY THROUGH THE WESTERN U.P. TO SOUTHERN MINNESOTA. A SURFACE RIDGE BLANKETS MUCH OF THE UPPER MISSISSIPPI RIVER VALLEY. THE SHORTWAVE OVER WISCONSIN WILL MOVE ACROSS UPPER MICHIGAN OVERNIGHT. THE SURFACE RIDGE WILL SHIFT SLIGHTLY EAST BUT STILL MAINLY OVER THE THE UPPER MISSISSIPPI RIVER VALLEY. THE COLD FRONT WILL PUSH INTO LOWER MICHIGAN AND CENTRAL WISCONSIN BY SUNRISE. THE AIR MASS OVER UPPER MICHIGAN WILL REMAIN FAIRLY DRY EXCEPT FOR THE SOUTH CENTRAL PART. IN SPITE OF THE INSTABILITY FROM THE SHORTWAVE AND FRONTAL SYSTEM...THE DRY CONDITIONS SHOULD LIMIT THE PRODUCTION OF ANY PRECIPITATION TONIGHT. A THETA-E RIDGE OVER THE FORECAST AREA THIS EVENING WILL SWEEP INTO NORTHERN LOWER MICHIGAN AND BECOME MORE FOCUSED OVERNIGHT. A FEW SHOWERS ARE SHOWING UP ALONG THE WISCONSIN BORDER. THUS WILL KEEP A CHANCE OF SHOWERS IN THAT AREA FOR THIS EVENING. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 415 PM EDT THU AUG 3 2006 .DISCUSSION... MAIN FCST CONCERNS ARE SHRA/TSRA POTENTIAL FRI NIGHT AND AGAIN SAT NIGHT INTO SUN. WV IMAGERY AND RUC ANALYSIS INDICATED A ZONAL PATTERN ACRS THE NRN CONUS WITH SEVERAL WEAK EMBEDDED SHRTWVS...MAINLY NORTH OF THE US/CANADIAN BORDER. THE MOST SIGNIFICANT UPSTREAM SHRTWV THAT WILL IMPACT THE WEATHER WAS LOCATED OVER NW BC...ASSOCIATED WITH A MID/UPPER LEVEL LOW OVER NRN BC/ALBERTA. A SHRTWV FROM N OF LK SUPERIOR INTO W UPR MI ALONG WITH A WEAK H8 TROF SUPPORTED ONLY PATCHY MID CLOUDS INTO W UPR MI EARLY TODAY. AT THE SFC...RELATIVELY WEAK PRES GRADIENT BTWN FRONTS OVER NW ONTARIO AND THE LOWER LAKES HAS ALLOWED LAKE BREEZES TO DEVELOP. VIS LOOP SHOWED ABUNDANT CU OVER CNTRL AND INTERIOR E UPR MI WITH RADAR INDICATING SOME ISOLD -SHRA OVER N CNTRL UPR MI. WITH MIXING PUSHING DEWPOINTS INTO THE LOWER 50S F...18Z LAPS SNDGS ONLY INDICATED 200-300 J/KG CAPE AT MOST. DEWPOINT EVEN LOWER OVER S(AROUND 50) WERE EVEN LESS FAVORABLE FOR -SHRA DEVELOPMENT TONIGHT...THE WEAK SHRTWV MOVING THROUGH THE REST OF UPR MI MAY BE ENOUGH TO SUPPORT ADDITIONAL -SHRA DEVELOPMENT. HOWEVER....GIVEN VERY LIMITED COVERAGE AND WEAK INTENSITY...ONLY ISOLD SHRA OR SPRINKLES WERE MENTIONED. DIURNAL -SHRA SHOULD THEN DIMINISH BY MID TO LATE EVENING. FRI INTO FRI NIGHT...PATTERN WILL PROGRESS AND AMPLIFY A BIT THE BC SHRTWV DIGS SE. THE RESULTING WAA PATTERN AND INCREASING 305K-310 ISENTROPIC LIFT FROM THE UPR MS VALLEY INTO THE WESTERN GREAT LAKES WILL SUPPORT A CHANCE OF SHRA/TSRA INTO UPR MI BY FRI EVENING INTO EARLY SAT. THE NAM/GFS HAVE BEEN INCONSISTENT WITH THE ASSOCIATED QPF PATTERN...SO CONTINUING 30 CHANCE POPS STILL SEEM APPROPRIATE WITH SLIGHTLY GREATER CHANCES FARTHER N OVER THE KEWEENAW...PER MDL CONSENSUS. FAVORABLE 0-6KM SHEAR VALUES TO NEAR 40-50 KT WOULD SUPPORT ORGANIZATION OF STRONGER AND POSSIBLY ISOLD SVR STORMS WITH FCST MUCAPE INTO THE 1000-1500 J/KG RANGE. HOWEVER...WITH MAINLY ELEVATED STORMS EFFECTIVE SHEAR VALUES WOULD BE LESS AND WOULD FAVOR MAINLY HAIL AS SVR THREAT. SAT...AFTER ANY MORNING CLOUDS AND CONVECTION MOVE OUT WAA WITH STIFF SW FLOW AND PLENTY OF SUNSHINE SHOULD BOOST TEMPS INTO THE UPPER 80S(MDLS FCST H8 TEMPS NEAR 17C)...SLIGHTLY ABV GUIDANCE...WITH EVEN WARMER READING FOR LOCATIONS FAVORED BY DOWNSLOPE FLOW. SAT NIGHT INTO SUN...THE PREFERRED 12Z GFS WAS SLIGHTLY FASTER THAN THE PREVIOUS RUN AND WAS ALSO SIMILAR TO THE ECMWF IN TIMING. HOWEVER...THE ECMWF/UKMET DID NOT BRING THE MID LVL LOW AS FAR SOUTH. EVEN THOUGH THE STRONG QG DYNAMICS WILL REMAIN N OF LK SUPERIOR...EXPECT SCT/NMRS SHRA/TSRA TO DEVELOP ALONG AND AHEAD OF A PRE-FRONTAL TROF. MOISTURE WILL NOT BE NEARLY AS ABUNDANT AS THE FRONT FROM EARLIER THIS WEEK WITH SFC DEWPOINTS ONLY TO AROUND 60F AND MUCAPE VALUES CLOSER TO 1K J/KG. SHEAR WILL BE STRONG ENOUGH WITH 0-6KM VALUES AGAIN NEAR 40-50KT TO SUPPORT SOME ISOLD STRONG TO SVR STORMS. MON-THU...THE ECMWF/UKMET/GFS WERE SIMILAR EARLY IN THE WEEK WITH HIGH PRES AND DRIER AIR DOMINATING THE UPPER GREAT LAKES. CONFIDENCE WAS MORE LIMITED BY THU WITH UNCERTAINTY IN WHETHER ANY SHRTWV OR MID LVL LOWS WILL MAKE AS MUCH PROGRESS INTO OR OVER THE RDG OVER THE CNTRL CONUS. HOWEVER...SINCE BOTH THE 12Z ECMWF AND GFS SUGGEST THIS POSSIBILITY...LOW END PCPN CHANCES WERE ADDED. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 840 PM CDT THU AUG 3 2006 .DISCUSSION... FNTL BNDRY SEEMS TO HV SETTLED S OF KSTL ERY THIS EVE. THIS SHUD LIMIT PCPN THRT...ALBEIT A LO ONE...TO OUR FAR S COUNTIES FOR RMNDR OF NGT AND HV MADE TWEEKS TO POPS TO ACCT FOR THIS. HV OPTED ATTM TO CONTINUE VRY LO POPS IN OUR XTRM SE COUNTIES AFT MIDN. THIS MAY BE HOLDING ONTO PCPN A BIT TOO LONG BUT WL MONITOR TRENDS OVR THE NXT FEW HRS BFR DROPPING PCPN ENTIRELY. ALSO ADJ CLDS A BIT...AS SWD PUSH OF SFC RDG AND DRIER AMS SHUD CAUSE FNTL CLD BAND TO SAG S WITH TIME. TRUETT && .AVIATION... FOR THE 00Z TAFS...WILL GO WITH A DRY FCST TGT AT ALL THE TAF SITES AS SCT TSRA ARE ALNG CDFNT WHICH HAS PUSHED JUST SE OF STL ATTM. SHOULD HAVE A CLRG SKY TGT AS DIURNAL CUMULUS CLOUDS DISSIPATE ARND SUNSET...AND MID-HI LVL CLOUDINESS OVR CNTRL MO ADVCTS SWD AS DEPICTED BY LATEST RUC RH FCST FOR TGT. SFC RDG EXTDG FM NERN CO NE THRU SRN MN WL BLD SEWD THRU MO IL BHND CDFNT. N-NWLY SFC WNDS OVR THE CWA TGT SHOULD BCM E-NELY ON FRI. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 700 PM CDT THU AUG 3 2006 .UPDATE... ONLY ISOLATED CONVECTION HAD DEVELOPED ACROSS CENTRAL MISSOURI LATE THIS AFTERNOON. THE BULK OF THE ACTIVITY WAS LOCATED TO THE SOUTH IN NORTHERN ARKANSAS AND OKLAHOMA. FORECAST GRIDS WILL BE ADJUSTED TO LOWER PRECIPITATION CHANCES THE REMAINDER OF TONIGHT. FOSTER && .DISCUSSION... SURFACE OBSERVATIONS INDICATE THAT A WEAK SURFACE BOUNDARY EXTENDS NE-SW SOUTH OF I-44. DENSE HIGH CLOUD COVER HAS KEPT TEMPERATURES DOWN A BIT OVER PORTIONS OF THE MO OZARKS. GOES SOUNDING AT KUNO STILL INDICATED A WEAK CAP AT NOON- 1PM...BUT WE ARE STARTING TO SEE SOME CUMULUS DEVELOPMENT WHERE THE SURFACE TEMPERATURE REACHING THE LOW 90S...BUT ANYTHING MORE THAN THAT LOOKS TO BE HARDER AND HARDER TO COME BY UNDER THE DENSE CIRRUS. SCATTERED CONVECTION HAS DEVELOPED SOUTH OF OF THE DENSE CLOUD COVER OVER NORTHERN ARKANSAS AND SOUTH CENTRAL MO. AFTERNOON 100MB MLCAPES OF 1000-1500 J/KG FROM THE RUC LOOK REASONABLE...SO ISOLATED CONVECTION SHOULD BE POSSIBLE WHERE LOCALIZED SURFACE CONVERGENCE OCCURS. AREAS OF SOUTHERN HOWELL AND OREGON COUNTIES...SOUTH OF THE HIGH CLOUDS WILL CONTINUE TO HAVE THE BEST SHORT TERM CHANCE FOR STORMS WHERE MLCAPES ARE CLOSE TO 2000 J/KG. HAVE INDICATED ISOLATED SEVERE CONVECTIVE WIND THREAT IN THE HWO...BUT NOT LOOKING AT ANYTHING WIDESPREAD ATTM. THE WEAK FRONT PUSHES SOUTH OF THE AREA FRIDAY AS HIGH PRESSURE MOVES EAST THROUGH IA/IL. STILL CAN'T RULE OUT SOME ISOLATED AFTERNOON/EVENING CONVECTION ALONG THE AR BORDER...BUT OTHERWISE IT LOOKS TO BE A QUIET DAY WITH SEASONABLE TEMPERATURES. FOR LATE FRIDAY NIGHT INTO SATURDAY MORNING...A SOUTHERLY RETURN FLOW DEVELOPS OVER KS/OK WITH ISENTROPIC UPGLIDE INDICATED IN THE 310-320K LAYERS OVER EASTERN KS AND WESTERN MO. HAVE ADDED A SLIGHT CHANCE POP TO COVER THIS...NOTHING MORE THAN 20 PERCENT. AGAIN...ALSO COULDN'T RULE OUT SOME ADDITIONAL ISOLATED ACTIVITY OVER SOUTHERN MO SATURDAY AFTERNOON/EVENING...BUT ATTM COVERAGE LOOKS TO BE FAIRLY SPARSE. A FAIRLY VIGOROUS SHORTWAVE IS PROGGED TO MOVE EAST ALONG THE U.S./CANADIAN BORDER LATE SATURDAY NIGHT AND EARLY SUNDAY. THE WRF AND GFS HANDLE THIS A BIT DIFFERENTLY IN TERMS OF SURFACE FEATURES OVER OUR REGION...WITH THE WRF PUSHING ANOTHER WEAK SURFACE BOUNDARY INTO THE MO OZARKS REGION SUNDAY MORNING...WHILE THE GFS KEEPS THE BOUNDARY FURTHER NORTH. IN EITHER CASE...THE MIDLEVEL RIDGING WHICH BUILDS BACK TO THE NORTH SHOULD PUT A LID ON ANY SIGNIFICANT PRECIPITATION ASSOCIATED WITH SURFACE/LOW LEVEL FEATURES. HIGH PRESSURE BUILDING INTO THE UPPER MIDWEST LATE SUNDAY-TUESDAY IN THE WAKE OF THE UPPER MIDWEST SHORTWAVE PUSHES A BACK DOOR COLD FRONT THROUGH THE NORTHEAST TWO THIRDS OF MO (AS DEPICTED BY THE GFS). I HAVE STUCK FAIRLY CLOSE TO GUIDANCE TEMPERATURES OVER THE NORTHEAST CWA...BUT HAVE BUMPED TEMPERATURES AT OR SLIGHTLY ABOVE GFS AND HPC GUIDANCE OVER SOUTHWEST MO AND SE KS. TEMPERATURES SHOULD REACH BACK UP INTO THE MID-UPPER 90S AND MAY TOUCH 100 DEG F IN SOME PLACES AGAIN EARLY NEXT WEEK. DSA && .AVIATION... VFR CONDITIONS WILL PREVAIL AT THE SPRINGFIELD AND JOPLIN TERMINALS TONIGHT AND FRIDAY. SCATTERED SHOWERS WILL BE CONFINED TO AREAS WELL TO THE EAST AND SOUTH OF THE TERMINALS THIS EVENING. NORTHERLY WINDS TONIGHT WILL SHIFT TO THE EAST FRIDAY. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 623 PM CDT THU AUG 3 2006 .DISCUSSION... COLD FRONT EXTENDS FROM SOUTH OF KIKK TO JUST NORTH OF KSTL...THEN INTO SWRN MO AS OF 19Z. SOME ISOLATED RWS/TRWS HAVE DEVELOPED OVER NERN IL...BUT LITTLE OR NO ACTIVITY OVER OUR CWA. AHEAD OF FRONT TEMPS HAVE RISEN INTO THE UPPER 80S TO LOWER 90S...WHILE THE LOWER 80S ARE THE RULE BEHIND THE BOUNDARY. MAIN FORECAST ISSUE IN THE VERY SHORT TERM ARE PCPN CHANCES FOR THIS EVENING AND HOW COOL IT WILL GET. WILL KEEP CHANCE POPS ALONG AND SOUTH OF A LINN MISSOURI TO WHITE HALL ILLINOIS LINE THIS EVENING...THEN SHIFT CHANCES FURTHER SOUTH AFTER 06Z. AS FOR LOW TEMPS...MID 60S TO AROUND 70...CLOSE TO THE MAV NUMBERS. AFTER TONIGHT...SFC RIDGING TO BUILD IN THROUGH THE FIRST PART OF THE WEEKEND...WITH DAYTIME HIGHS IN THE UPPER 80S TO LOWER 90S AND LOWS IN THE MID TO UPPER 60S. MODELS STARTING TO GET A BETTER HANDLE ON SYSTEM THAT WILL APPROACH AREA BEGINNING SATURDAY NIGHT AND CONTINUING THROUGH TUESDAY NIGHT...WITH BEST CHANCES MONDAY AND TUESDAY. FOR NOW WILL STAY WITH SLIGHT CHANCE POPS THROUGH THIS PERIOD. BEYOND TUESDAY...SHOULD SEE DRY WEATHER. BYRD && .AVIATION... FOR THE 00Z TAFS...WILL GO WITH A DRY FCST TGT AT ALL THE TAF SITES AS SCT TSRA ARE ALNG CDFNT WHICH HAS PUSHED JUST SE OF STL ATTM. SHOULD HAVE A CLRG SKY TGT AS DIURNAL CUMULUS CLOUDS DISSIPATE ARND SUNSET...AND MID-HI LVL CLOUDINESS OVR CNTRL MO ADVCTS SWD AS DEPICTED BY LATEST RUC RH FCST FOR TGT. SFC RDG EXTDG FM NERN CO NE THRU SRN MN WL BLD SEWD THRU MO IL BHND CDFNT. N-NWLY SFC WNDS OVR THE CWA TGT SHOULD BCM E-NELY ON FRI. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 325 PM CDT THU AUG 3 2006 .DISCUSSION... THE UPPER LEVEL HIGH PRESSURE RIDGE HAS FINALLY BEEN DISPLACED TO THE LOWER MISSISSIPPI RIVER VALLEY TODAY AS A SURFACE FRONT HAS SUNK SOUTH TO NEAR A KSTL-KJLN LINE THIS AFTERNOON. A THICKER STRATO-CU LAYER REMAINS POOLED ALONG THE WEAK BAROCLINIC FRONTAL BOUNDARY...WHILE A MORE SCATTERED DECK HAS EVOLVED IN THE DRIER AIR WELL BEHIND THE FRONT. WITH THE LOSS OF DAYTIME HEATING AND THE ADVECTION OF EVEN DRIER BOUNDARY LAYER AIR INTO THE NORTHERN HALF OF MISSOURI AND KANSAS...EXPECT THE SCATTERED LAYER TO DISSIPATE NEAR SUNSET. HOWEVER...HIGHER BOUNDARY LAYER MOISTURE ALONG THE FRONT AND MIDLEVEL CLOUDS STREAMING IN FROM NRN OKLAHOMA WILL KEEP SOME ASSEMBLENCE OF CLOUD COVER ACROSS CENTRAL MISSOURI FOR AT LEAST OF THE FIRST HALF OF THE NIGHTTIME PERIOD. THE AREA WILL EXPERIENCE ONE OF THE MOST PLEASANT EVENINGS AND OVERNIGHTS SEEN IN OVER A WEEK WITH SURFACE DEWPOINTS FALLING INTO THE UPPER 50S TO LOWER 60S. AIR TEMPERATURE WILL FOLLOW SUIT AND FALL THROUGH THE 70S DURING THE EVENING HOURS. KEPT OVERNIGHT LOW TEMPERATURES OVER THE AREA IN THE LOWER TO MID 60S...HOWEVER WITH WEAK WINDS AND ONLY MARGINALLY SHALLOW MOISTURE /900MB DEWPOINTS +10C/...COULD SEE A FEW LOCALS EVEN DROP INTO THE UPPER 50S BY THE EARLY MORNING HOURS. VERY SHALLOW INVERSION WILL MIX QUICKLY DURING THE MORNING HOURS WITH AFTERNOON TEMPERATURES RISING TO NEAR CLIMATOLOGICAL NORMALS IN THE MID 80S TO NEAR 90 DEGREES. DEEPER EASTERLY FLOW WILL MAINTAIN LOW BOUNDARY LAYER MOISTURE VALUES...AND AFTERNOON RH VALUES WILL FALL TO UNSEASONABLY LOW LEVELS...MAKING FOR A DELIGHTFUL END OF THE WEEK. THE AFOREMENTIONED FRONTAL BOUNDARY WILL BEGIN TO LIFT BACK NORTH EARLY SATURDAY AS 5H HEIGHTS ONCE AGAIN BUILD OVER THE REGION. MODELS INDICATE SOME ISENTROPIC LIFT THROUGH THE 310K TO 315K LAYER SATURDAY MORNING...HOWEVER THE BEST FLOW AND STEEPEST GRADIENTS LOOKS TO BE NORTH OF THE AREA. IN ADDITION...RISING MIDLEVEL HEIGHTS ABOVE THE MOISTURE IN THE 310K TO 315K LAYER WILL BECOME NON-SUPPORTIVE FOR MAINTAINING ISENTROPICALLY LIFTED CONVECTION. REGARDLESS...WITH 5H HEIGHTS BUILDING TO NEAR 590DM AND 850MB TEMPERATURES RISING BACK TO THE +22C TO +25C RANGE...AFTERNOON HIGHS WILL ONCE AGAIN PUSH INTO THE LOWER 90S EAST...AND THE MID TO UPPER 90S WEST BEGINNING SATURDAY. USED A BLEND OF THE 00Z ECMWF AND 06Z GFS FOR THE SUNDAY-WEDNESDAY TIME FRAME. PREFERRED THE LESS AGRESSIVE GFS OVER THE NAM EXTENSION WITH RESPECT TO A NEWLY DEVELOPING FRONT FORECAST TO PUSH SOUTH TOWARDS NORTHERN MISSOURI. NAM APPEARS TO DIG ENERGY TOO FAR SOUTH INTO THE GREAT LAKES AND OHIO RIVER VALLEY IN RESPONSE TO A FORECAST WEAKNESS IN THE MIDLEVEL RIDGE. FEEL THE BULK OF THE ENERGY WILL INSTEAD SLIDE EAST AND PHASE WITH BROAD TROUGHING OVER THE CANADIAN MARITIMES. THEREAFTER...THE FRONT BECOMES HUNG SOMEWHERE ACROSS NORTHERN MISSOURI WITH THE MIDLEVEL RIDGE MAINTAINING ITS STRENGTH OVER THE REGION. THIS BOUNDARY WILL PROVIDE THE FOCUS FOR POSSIBLE THUNDERSTORM DEVELOPMENT THROUGH THE FIRST HALF OF NEXT WEEK...HOWEVER LACK OF DETAILS REGARDING ANY SPECIFIC WAVE ROTATING AROUND AND THROUGH THE RIDGE TO HELP TRIGGER CONVECTION PRECLUDES ANY MORE THAN A SLIGHT CHANCE MENTION IN THE GRIDS. KEPT TEMPERATURES SLIGHTLY ABOVE NORMALS IN THIS TIME PERIOD...HOWEVER UPWARD REVISIONS MAY BE NECESSARY WHEN IT CAN BE DETERMINED WHICH SPECIFIC DAYS WILL NOT SEE PRECIPITATION AND CLOUD COVER. 21 && .PREV DISCUSSION... /ISSUED 1202 PM CDT THU AUG 3 2006/ UPDATED THE AFTERNOON FORECAST TO REMOVE PRECIPITATION CHANCES OVER SRN COUNTIES AS WHAT LITTLE MID LEVEL FORCING REMAINS HAS SHIFTED SOUTH INTO THE OZARKS REGION. THICK STRATO-CUMULUS CONTINUES TO HOLD OVER THE SE THIRD OF THE CWA WHERE LOW LEVEL MOISTURE REMAINS POOLED ALONG THE DISSIPATING BAROCLINIC ZONE. IMPROVEMENT WILL BE SLOW AS UPSTREAM LOW LEVEL FLOW IS TOO WEAK TO ENHANCE MIXING/DRY ADVECTION. THEREFORE...HAVE LOWERED TEMPERATURES 3-4F OVER CENTRAL MO. EXPECT THAT MAX TEMPS ACROSS THE REGION WILL END UP FAIRLY HOMOGENEOUS BY DAYS END AS A RESULT OF COLD ADVECTION OR CLOUD COVER. BOOKBINDER && /ISSUED 228 AM CDT THU AUG 3 2006/ SHORT WAVE WHICH CAME OUT OF KANSAS WEDNESDAY EVENING...AND BROUGHT WIDESPREAD RAINS TO NORTHEAST KANSAS AND NORTHERN MISSOURI...WILL BE EXITING THE FORECAST AREA BY 12Z THIS MORNING. THIS INITIAL WAVE BEING KICKED OUT BY A NORTHERN STREAM WAVE WHICH PROFILERS SHOW CURRENTLY EXTENDING FROM SOUTHEAST SOUTH DAKOTA INTO CENTRAL NEBRASKA. NOT OUT OF THE QUESTION THIS SECONDARY WAVE MAY PRODUCE SOME ADDITIONAL SHOWER ACTIVITY IN NORTH CENTRAL MISSOURI THIS MORNING ALONG THE 850 MB FRONT...PER THE NAM/WRF AND GFS...ALTHOUGH SOME DOUBT IN THESE MODELS SINCE THEY DO NOT SEEM TO HAVE A VERY GOOD HANDLE ON THE INITIAL WAVE COMING THROUGH AT THIS TIME. RUC SEEMS TO HAVE A BETTER HANDLE ON THE PATTERN...AND IT TOO PRODUCES SOME PRECIPITATION THIS MORNING ALONG THE 850 FRONT IN NORTH CENTRAL MISSOURI...SO WILL LEAVE SOME LOW POPS GOING IN THAT AREA. FURTHER SOUTH...ONGOING PRECIPITATION NEAR SURFACE FRONT SHOULD CONTINUE PAST 12Z...BUT WITH SURFACE BOUNDARY SLIPPING FURTHER TO THE SOUTH...CHANCES OF PRECIPITATION ASSOCIATED WITH THE FRONT SHOULD ALSO BE SLIDING SOUTH OF AREA. WILL LEAVE SOME LOW POPS IN FOR THIS MORNING...BUT CUT BACK POPS FOR THIS AFTERNOON WITH ONLY THE EXTREME SOUTHEAST PARTS OF FORECAST AREA STILL WITH MENTION OF PRECIPITATION AS 850 FRONT DROPS THROUGH THE REGION. SURFACE AND UPPER RIDGING BUILDING IN OVERNIGHT TONIGHT SHOULD KEEP THINGS DRY. SOME CONCERN OF WARM AIR ADVECTION SETTING UP FRIDAY NIGHT AS A SHORT WAVE MOVES OUT OF NORTHERN ROCKIES TOWARD THE NORTHERN PLAINS. STILL A GOOD DEAL OF UNCERTAINTY EXACTLY WHERE THE STRONGEST ISENTROPIC LIFT ON THE 310K SURFACE WILL SET UP...WITH THE NAM/WRF POINTING MORE TOWARD EASTERN KANSAS AND INTO WESTERN MISSOURI...WHILE THE GFS KEEPS IT FOCUSED FURTHER TO THE WEST IN KANSAS. WITH SO MUCH UNCERTAINTY...WILL LEAVE MENTION OF ANY PRECIPITATION OUT OF FORECAST AT THIS POINT WITH ONLY SLIGHT CHANCE POPS IN EASTERN KANSAS AND WESTERN MISSOURI FRIDAY NIGHT. IT IS SOMETHING THAT WILL NEED TO BE WATCHED. FINALLY WILL HAVE A BREAK FROM THE UNSEASONABLY HOT WEATHER TODAY WITH 850 MB TEMPERATURES FINALLY COOLING TO BELOW 20 DEGREES. THIS SLIGHT COOL DOWN SHOULD LAST INTO THE DAY ON FRIDAY AS SURFACE WINDS GRADUALLY SWING FROM THE NORTH AROUND TO THE SOUTHEAST. WARM UP ON SATURDAY HINGES ON EXACTLY HOW FAR EAST WARM AIR ADVECTION SETS UP. FOR NOW WITH UNCERTAINTY IN THE MODELS...WILL GO WITH A COMPROMISE BETWEEN NAM/WRF AND GFS SOLUTION PC && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 257 PM CDT THU AUG 3 2006 .DISCUSSION... SURFACE OBSERVATIONS INDICATE THAT A WEAK SURFACE BOUNDARY EXTENDS NE-SW SOUTH OF I-44. DENSE HIGH CLOUD COVER HAS KEPT TEMPERATURES DOWN A BIT OVER PORTIONS OF THE MO OZARKS. GOES SOUNDING AT KUNO STILL INDICATED A WEAK CAP AT NOON- 1PM...BUT WE ARE STARTING TO SEE SOME CUMULUS DEVELOPMENT WHERE THE SURFACE TEMPERATURE REACHING THE LOW 90S...BUT ANYTHING MORE THAN THAT LOOKS TO BE HARDER AND HARDER TO COME BY UNDER THE DENSE CIRRUS. SCATTERED CONVECTION HAS DEVELOPED SOUTH OF OF THE DENSE CLOUD COVER OVER NORTHERN ARKANSAS AND SOUTH CENTRAL MO. AFTERNOON 100MB MLCAPES OF 1000-1500 J/KG FROM THE RUC LOOK REASONABLE...SO ISOLATED CONVECTION SHOULD BE POSSIBLE WHERE LOCALIZED SURFACE CONVERGENCE OCCURS. AREAS OF SOUTHERN HOWELL AND OREGON COUNTIES...SOUTH OF THE HIGH CLOUDS WILL CONTINUE TO HAVE THE BEST SHORT TERM CHANCE FOR STORMS WHERE MLCAPES ARE CLOSE TO 2000 J/KG. HAVE INDICATED ISOLATED SEVERE CONVECTIVE WIND THREAT IN THE HWO...BUT NOT LOOKING AT ANYTHING WIDESPREAD ATTM. THE WEAK FRONT PUSHES SOUTH OF THE AREA FRIDAY AS HIGH PRESSURE MOVES EAST THROUGH IA/IL. STILL CAN'T RULE OUT SOME ISOLATED AFTERNOON/EVENING CONVECTION ALONG THE AR BORDER...BUT OTHERWISE IT LOOKS TO BE A QUIET DAY WITH SEASONABLE TEMPERATURES. FOR LATE FRIDAY NIGHT INTO SATURDAY MORNING...A SOUTHERLY RETURN FLOW DEVELOPS OVER KS/OK WITH ISENTROPIC UPGLIDE INDICATED IN THE 310-320K LAYERS OVER EASTERN KS AND WESTERN MO. HAVE ADDED A SLIGHT CHANCE POP TO COVER THIS...NOTHING MORE THAN 20 PERCENT. AGAIN...ALSO COULDN'T RULE OUT SOME ADDITIONAL ISOLATED ACTIVITY OVER SOUTHERN MO SATURDAY AFTERNOON/EVENING...BUT ATTM COVERAGE LOOKS TO BE FAIRLY SPARSE. A FAIRLY VIGOROUS SHORTWAVE IS PROGGED TO MOVE EAST ALONG THE U.S./CANADIAN BORDER LATE SATURDAY NIGHT AND EARLY SUNDAY. THE WRF AND GFS HANDLE THIS A BIT DIFFERENTLY IN TERMS OF SURFACE FEATURES OVER OUR REGION...WITH THE WRF PUSHING ANOTHER WEAK SURFACE BOUNDARY INTO THE MO OZARKS REGION SUNDAY MORNING...WHILE THE GFS KEEPS THE BOUNDARY FURTHER NORTH. IN EITHER CASE...THE MIDLEVEL RIDGING WHICH BUILDS BACK TO THE NORTH SHOULD PUT A LID ON ANY SIGNIFICANT PRECIPITATION ASSOCIATED WITH SURFACE/LOW LEVEL FEATURES. HIGH PRESSURE BUILDING INTO THE UPPER MIDWEST LATE SUNDAY-TUESDAY IN THE WAKE OF THE UPPER MIDWEST SHORTWAVE PUSHES A BACK DOOR COLD FRONT THROUGH THE NORTHEAST TWO THIRDS OF MO (AS DEPICTED BY THE GFS). I HAVE STUCK FAIRLY CLOSE TO GUIDANCE TEMPERATURES OVER THE NORTHEAST CWA...BUT HAVE BUMPED TEMPERATURES AT OR SLIGHTLY ABOVE GFS AND HPC GUIDANCE OVER SOUTHWEST MO AND SE KS. TEMPERATURES SHOULD REACH BACK UP INTO THE MID-UPPER 90S AND MAY TOUCH 100 DEG F IN SOME PLACES AGAIN EARLY NEXT WEEK. DSA && .AVIATION... WEAK SURFACE FRONT SITUATED ROUGHLY ALONG INTERSTATE 44 AT 17Z. WINDS HAVE BEGUN TO SHIFT TO A W-NW DIRECTION AT BOTH THE KSGF AND KJLN TERMINALS. SCATTERED CONVECTION HAS BEGUN TO DEVELOP ALONG THE PRE-FRONTAL TROUGH OVER ARKANSAS. WITH DIMINISHED CONVECTIVE CHANCES...WILL AMEND TO REMOVE VCTS FOR BOTH TERMINALS. EXPECT VFR CONDITIONS THROUGH THE REMAINDER OF THE PERIOD WITH LIGHT WINDS OVERNIGHT VEERING AROUND TO EASTERLY AFTER SUNRISE. GAEDE && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 1202 PM CDT THU AUG 3 2006 .DISCUSSION... SHORT TERM UPDATE... UPDATED THE AFTERNOON FORECAST TO REMOVE PRECIPITATION CHANCES OVER SRN COUNTIES AS WHAT LITTLE MID LEVEL FORCING REMAINS HAS SHIFTED SOUTH INTO THE OZARKS REGION. THICK STRATO-CUMULUS CONTINUES TO HOLD OVER THE SE THIRD OF THE CWA WHERE LOW LEVEL MOISTURE REMAINS POOLED ALONG THE DISSIPATING BAROCLINIC ZONE. IMPROVEMENT WILL BE SLOW AS UPSTREAM LOW LEVEL FLOW IS TOO WEAK TO ENHANCE MIXING/DRY ADVECTION. THEREFORE...HAVE LOWERED TEMPERATURES 3-4F OVER CENTRAL MO. EXPECT THAT MAX TEMPS ACROSS THE REGION WILL END UP FAIRLY HOMOGENEOUS BY DAYS END AS A RESULT OF COLD ADVECTION OR CLOUD COVER. BOOKBINDER && .PREV DISCUSSION... /ISSUED 228 AM CDT THU AUG 3 2006/ SHORT WAVE WHICH CAME OUT OF KANSAS WEDNESDAY EVENING...AND BROUGHT WIDESPREAD RAINS TO NORTHEAST KANSAS AND NORTHERN MISSOURI...WILL BE EXITING THE FORECAST AREA BY 12Z THIS MORNING. THIS INITIAL WAVE BEING KICKED OUT BY A NORTHERN STREAM WAVE WHICH PROFILERS SHOW CURRENTLY EXTENDING FROM SOUTHEAST SOUTH DAKOTA INTO CENTRAL NEBRASKA. NOT OUT OF THE QUESTION THIS SECONDARY WAVE MAY PRODUCE SOME ADDITIONAL SHOWER ACTIVITY IN NORTH CENTRAL MISSOURI THIS MORNING ALONG THE 850 MB FRONT...PER THE NAM/WRF AND GFS...ALTHOUGH SOME DOUBT IN THESE MODELS SINCE THEY DO NOT SEEM TO HAVE A VERY GOOD HANDLE ON THE INITIAL WAVE COMING THROUGH AT THIS TIME. RUC SEEMS TO HAVE A BETTER HANDLE ON THE PATTERN...AND IT TOO PRODUCES SOME PRECIPITATION THIS MORNING ALONG THE 850 FRONT IN NORTH CENTRAL MISSOURI...SO WILL LEAVE SOME LOW POPS GOING IN THAT AREA. FURTHER SOUTH...ONGOING PRECIPITATION NEAR SURFACE FRONT SHOULD CONTINUE PAST 12Z...BUT WITH SURFACE BOUNDARY SLIPPING FURTHER TO THE SOUTH...CHANCES OF PRECIPITATION ASSOCIATED WITH THE FRONT SHOULD ALSO BE SLIDING SOUTH OF AREA. WILL LEAVE SOME LOW POPS IN FOR THIS MORNING...BUT CUT BACK POPS FOR THIS AFTERNOON WITH ONLY THE EXTREME SOUTHEAST PARTS OF FORECAST AREA STILL WITH MENTION OF PRECIPITATION AS 850 FRONT DROPS THROUGH THE REGION. SURFACE AND UPPER RIDGING BUILDING IN OVERNIGHT TONIGHT SHOULD KEEP THINGS DRY. SOME CONCERN OF WARM AIR ADVECTION SETTING UP FRIDAY NIGHT AS A SHORT WAVE MOVES OUT OF NORTHERN ROCKIES TOWARD THE NORTHERN PLAINS. STILL A GOOD DEAL OF UNCERTAINTY EXACTLY WHERE THE STRONGEST ISENTROPIC LIFT ON THE 310K SURFACE WILL SET UP...WITH THE NAM/WRF POINTING MORE TOWARD EASTERN KANSAS AND INTO WESTERN MISSOURI...WHILE THE GFS KEEPS IT FOCUSED FURTHER TO THE WEST IN KANSAS. WITH SO MUCH UNCERTAINTY...WILL LEAVE MENTION OF ANY PRECIPITATION OUT OF FORECAST AT THIS POINT WITH ONLY SLIGHT CHANCE POPS IN EASTERN KANSAS AND WESTERN MISSOURI FRIDAY NIGHT. IT IS SOMETHING THAT WILL NEED TO BE WATCHED. FINALLY WILL HAVE A BREAK FROM THE UNSEASONABLY HOT WEATHER TODAY WITH 850 MB TEMPERATURES FINALLY COOLING TO BELOW 20 DEGREES. THIS SLIGHT COOL DOWN SHOULD LAST INTO THE DAY ON FRIDAY AS SURFACE WINDS GRADUALLY SWING FROM THE NORTH AROUND TO THE SOUTHEAST. WARM UP ON SATURDAY HINGES ON EXACTLY HOW FAR EAST WARM AIR ADVECTION SETS UP. FOR NOW WITH UNCERTAINTY IN THE MODELS...WILL GO WITH A COMPROMISE BETWEEN NAM/WRF AND GFS SOLUTION PC && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 254 PM EDT THU AUG 3 2006 .SYNOPSIS... THE REMNANTS OF OUR TROPICAL AIRMASS WILL SLOWLY SETTLE TO THE SOUTH LATER TONIGHT AND FRIDAY...WITH FAIR AND MORE SEASONABLE CONDITIONS TAKING OVER FOR THE UPCOMING WEEKEND. WHILE TEMPERATURES THIS WEEKEND WILL STILL AVERAGE A LITTLE ABOVE NORMAL...HUMIDITY LEVELS WILL BE NOTICEABLY LOWER. A TROUGH IS THEN FORECAST TO SET UP ACROSS THE EASTERN GREAT LAKES AND NEW ENGLAND FOR THE FIRST HALF OF NEXT WEEK...AND THIS WILL TRANSLATE INTO NEAR TO BELOW NORMAL MERCURY READINGS WITH LITTLE OR NO PRECIPITATION. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... UNSETTLED CONDITIONS ARE STILL ANTICIPATED FOR THE BULK OF THE FORECAST AREA EARLY TONIGHT AS A WAVY FRONTAL BOUNDARY WILL CONTINUE TO SINK SOUTH INTO PENNSYLVANIA. THE 12Z NAM/WRF AND GFS ARE NOT HANDLING THE CURRENT CONDITIONS VERY WELL...SO AM SKEPTICAL TO RELY ON THEM FOR THE FIRST PERIOD. THE RUC IS ALSO WOEFULLY OUT OF TOUCH AS WELL...SO AM USING SAT IMAGERY AND RADAR TRENDS AS THE MAIN FORECAST TOOL THROUGH ABOUT 06Z. WITH THAT BEING SAID...THE LAST IN A SERIES OF WAVES WAS OVER WESTERN OHIO AT 18Z. THIS WAVE WILL MOVE ACROSS OR JUST TO OUR SOUTH EARLY TONIGHT. ONCE IT MOVES TO OUR EAST...THE WAVY FRONT WILL JUMP TO THE SOUTH AND ALLOW DRIER AIR TO MOVE ACROS OUR REGION FROM WISCONSIN AND MICHIGAN. HAVE RAISED POPS TO CAT FOR A LARGE PORTION OF THE REGION DURING THE FIRST HALF OF TONIGHT...WHILE THE NORTH COUNTRY AND AREAS BORDERING THE U.S. LAKE ONTARIO NEARSHORES WILL HAVE LIKELY POPS. WHILE THERE WILL BE THE CHANCE FOR ANOTHER THUNDERSTORM OR TWO AROUND...THE AIRMASS OVER NEW YORK HAS STABILIZED A BIT SINCE THE MIDDAY. MUCH MORE UNSTABLE CONDITIONS WILL BE FOUND SOUTH OF THE BORDER WHERE STRONG TO SEVERE WEATHER WILL STILL BE POSSIBLE THIS EVENING. A DRIER AIRMASS WILL THEN ARRIVE IN FORCE DURING THE DAY FRIDAY AS A SFC HIGH WILL NOSE ITS WAY ACROSS MICHIGAN AND LAKE ERIE. SKIES WILL BECOME P/M SUNNY FOR ALL AREAS...WITH ONLY A CHANCE FOR A LEFTOVER MORNING SHOWER OVER THE SRN TIER. A FLAT RIDGE WILL PROGRESS ACROSS THE UPPER OHIO VALLEY AND EASTERN GREAT LAKES SATURDY AND SUNDAY. THIS WILL BRING BEAUTIFUL WEATHER TO THE REGION WITH AMPLE SUNSHINE. TEMPERATURES WILL BE WARM DURING THE AFTERNOONS...BUT COMFORTABLE/TOLERABLE AT NIGHT. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... OUR NEXT REAL THREAT OF SHOWERS OR THUNDERSTORMS WILL BE AFTER THE BEAUTIFUL WEEKEND IS OVER. MODEL RUNS FROM YESTERDAY AND TODAY ARE CONSISTENT IN MOVING A VIGOROUS UPPER TROUGH FROM ONTARIO INTO QUEBEC SUNDAY NIGHT. THE RESULTING SURFACE LOW ACROSS QUEBEC WOULD DRAG A COLD FRONT SOUTHEASTWARD ACROSS US ON MONDAY. THE BEST CHANCE OF PRECIPITATION WILL BE LATE SUNDAY NIGHT AND MONDAY. THE VIGOROUS TROUGH WILL AMPLIFY A BIT AND MOVE EAST FROM MONDAY NIGHT THROUGH WEDNESDAY IN RESPONSE TO AN UPPER RIDGE FORECAST TO BUILD OVER THE PLAINS. THIS WILL PROVIDE US WITH A VERY NICE TUESDAY THROUGH THURSDAY PERIOD WITH SURFACE HIGH PRESSURE ALONG WITH COMFORTABLE TEMPERATURES AND HUMIDITIES. && .AVIATION... ALTHOUGH A COLD FRONT IS DRAPED ACROSS OUR CWA CEILINGS AND VISIBILITIES WILL BE GENERALLY VFR THROUGH MIDNIGHT. OCCASIONAL SHOWERS OR THUNDERSTORMS WILL REDUCE CONDITIONS TO MVFR WITH LOCAL IFR VISIBILITIES. CONDITIONS WILL BE BETTER NORTH OF THE FRONT ACROSS THE EASTERN LAKE ONTARIO COUNTIES. AFTER MIDNIGHT THE PRECIPITATION WILL SLIDE FURTHER SOUTH. LIGHT WINDS AND PARTIAL CLEARING MAY LEAD TO VISIBILITIES OF 2 TO 3 MILES IN FOG. VFR CONDITIONS WILL RESUME FRIDAY AS THE FRONT PUSHES EVEN FURTHER SOUTH. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...RSH SHORT TERM...RSH LONG TERM...SAGE AVIATION...SAGE ny AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BUFFALO NY 1200 PM EDT THU AUG 3 2006 .UPDATE... AS SUGGESTED IN THE LAST UPDATE...STRONG TO SEVERE STORMS WILL MOVE ACROSS THE WESTERN SOUTHERN TIER DURING THE NEXT FEW HOURS. SPS HAS JUST ISSED A SEVERE THUNDERSTORM WATCH FOR ALLEGANY... CATTARAUGUS AND CHAUTAUQUA COUNTIES UNTIL 8 PM EDT THIS EVENING. ENOUGH DIURNAL HEATING HAS TAKEN PLACE ACROSS THE WATCH AREA TO RAISE SBCAPES TO >1500 J/KG AND ENOUGH SPEED SHEAR IS FOUND ABOVE 3K FT TO ACCOUNT FOR 0-2 KM HELICITY VALUES >100 M2/S2. AGAIN... ORGANIZED MESOS ARE NOT AS LIKELY AS BOWING SEGMENTS SO THE MAIN THREAT OF SEVERE WEATHER WOULD BE STRAIGHT LINE WINDS. HIGH PWATS WOULD ALSO MEAN THE OPPORTUNITY FOR VERY HEAVY RAINS... WITH THE THREAT OF FLOODING IF TRAINING CELLS DEVELOP. AT THIS POINT THEY HAVE NOT AND DO NOT LOOK LIKELY FOR OUR SRN TIER. RSH && .PREV DISCUSSION... /ISSUED 931 AM EDT THU AUG 3 2006/ UPDATE... A COOL FRONTAL BOUNDARY WILL SAG ACROSS THE FORECAST AREA THIS AFTERNOON AND TONIGHT AND WILL SERVE TO BE THE FOCUS FOR SOME -SHRA/TSRA. PWATS ARE IN THE RANGE OF 1.75-2.0...SO ANY CONVECTION COULD INCLUDE SOME VERY HEAVY RAIN. WHILE THE WINDS HAVE SHIFTED TO A MORE NORTHWESTERLY DIRECTION FOR MANY OF THE REPORTING SITES AS OF 14Z (BUF, ROC, IAG)...THE ACTUAL COOL FRONT IS STILL TO OUR NORTH. THE VEERING WINDS MAY BE A RESULT OF AN OUTFLOW BOUNDARY OR SOME OTHER MESOSCALE FEATURE. SFC WINDS WILL LIKELY GO BACK TO THE WEST OR SOUTHWEST THIS AFTERNOON AS THE FRONT WILL SLOWLY SETTLE SOUTHWARDS. THERE ARE STILL SEVERAL WAVES ANALYZED ALONG THE FRONT TO OUR WEST TO BELIEVE THAT A STRONG SOUTHWARD PUSH WILL TAKE PLACE ANYTIME REAL SOON. IN ANY CASE...LIKELY POPS WILL REMAIN IN PLACE FOR THE REGION THIS AFTERNOON. THOSE POPS WILL DROP OFF FROM NORTH TO SOUTH DURING THE LATE AFTERNOON AND EVENING...WHEN THE LAST WAVE ALONG THE FRONT WILL CLEAR TO THE NORTHEAST. IN TERMS OF STRONG/SEVERE THUNDERSTORMS...THE SOUTHERN COUNTIES WILL HAVE THE HIGHEST PROBABILITY OF EXPERIENCING ANYTHING SIGNIFICANT. THE AIRMASS IS ALREADY MORE UNSTABLE WELL SOUTH OF BUFFALO AND ROCHESTER AND DIURNAL AFFECTS COULD ADD TO THIS INSTABILITY (THINNER CLOUD COVER TO THE SOUTH) AS THE MIDDAY PROGRESSES. THE SPC SLGHT RIOSK OUTLINE FOR TODAY INCLUDES OUR SOUTHERN TIER AND A PORTION OF THE FINGER LAKES REGION. THE WIND FIELD SCF-10K SHOWS LITTLE SHEAR AT THIS TIME...WITH NEAR UNIDIRECTIONAL FLOW ANTICIPATED TO REMAIN INTACT FOR MUCH OF THE AFTERNOON. THE ONLY SHEAR WILL BE SUPPLIED BY THE 35-40 KT WINDS ABOVE 5K. STRAIGHT LINE WINDS WILL THUS REMAIN THE MAIN THREAT IN TERMS OF SEVERE WEATHER TYPE...AS THE FRZG LEVEL REMAINS ABOVE 16K FEET WITH ONLY MARGINAL SHEAR TO SUPPORT ANY ORGANIZED MESO'S. WOULD NEED TO UTILILIZE ALL OF 2000 J/KG PROJECTED EARLY AFTERNOON CAPES FOR THE SOUTHERN TIER TO HAVE ANY REAL CHANCE OF PRODUCING SIGNIFICANT HAIL. RSH PREV DISCUSSION... /ISSUED 642 AM EDT THU AUG 3 2006/ UPDATE... THE ACTIVE CONVECTION THAT IS FIRING UP OVER ILLINOIS AND NORTHERN INDIANA SEEMS TO BE ROBBING SOME OF THE ENERGY FROM THE EASTERN END OF THE COLD FRONT. THE LATEST RUC GUIDANCE AGREES WITH THE EARLIER WRF THAT THE STRONGEST INSTABILITY WILL STAY SOUTH OF OUR CWA. BASED ON THIS TREND...HAVE DECIDED TO DOWNPLAY THE THUNDERSTORMS A BIT IN THE ZFP...BUT WILL LEAVE IN THE WORDING FOR THE POSSIBILITY OF HEAVY RAIN DUE TO THE VERY MOIST AIRMASS THAT IS STILL PLACE ACROSS NEW YORK STATE. PREV DISCUSSION... /ISSUED 344 AM EDT THU AUG 3 2006/ SHORT TERM /TODAY THROUGH SATURDAY/... THE COLD FRONT THAT STRETCHES FROM JUST NORTH OF LAKE ONTARIO TO CENTRAL MICHIGAN WILL DRIFT SLOWLY TO THE SOUTH TODAY AS THE UPPER LEVEL RIDGE CONTINUES TO FLATTEN. ONE AREA OF SHOWERS AND SCATTERED THUNDERSTORMS IS CURRENTLY PUSHING THROUGH WESTERN NEW YORK STATE...WHILE A SECOND BATCH OF CONVECTION IS FIRING UP OVER THE SOUTHERN HALF OF MICHIGAN. THE ONGOING CONVECTION IS NOT AS STRONG AS THAT WHICH AFFECTED PARTS OF THE CWA EARLIER IN THE NIGHT...BUT THE ATMOSPHERE SOUTH OF THE FRONT IS STILL VERY HUMID AND RATHER UNSTABLE. THEREFORE...WILL FOLLOW CONTINUITY AND LEAVE IN LIKELY POPS FOR TODAY. THE LATEST WRF NOW TRACKS THE COLD FRONT SOUTH ACROSS OUR CWA A LITTLE FASTER THAN THE GFS. THE GFS SEEMS MORE REASONABLE CONSIDERING HOW FRONT IS GETTING HUNG UP ALONG THE NORTHERN EDGE OF THE STRONG UPPER RIDGE...AS IS OFTEN THE CASE AT THIS TIME OF THE YEAR. THE MODELS SUGGEST THAT THE MOST UNSTABLE AIR WILL LIE JUST SOUTH OF NEW YORK STATE TODAY (SPC KEEPS THE SLIGHT RISK AREA MAINLY SOUTH OF OUR CWA)...BUT HEAVY RAIN IS A CONCERN AS MOISTURE FROM UPSTREAM CONVECTION CONTINUES TO POOL AHEAD OF THE SLOW MOVING FRONT. THE WRF ALSO SHOWS PRECIPITABLE WATER VALUES APPROACHING 2 INCHES DURING THE MID AFTERNOON. EXPECT AREA TEMPERATURES TO BE 10 TO 15 DEGREES COOLER THAN THE OPPRESSIVE READINGS OF THE FIRST HALF OF THE WEEK...BUT THERE WILL NOT BE A LOT OF RELIEF FROM THE UNCOMFORTABLE CONDITIONS AS HUMIDITY LEVELS WILL STILL REMAIN HIGH. SCATTERED SHOWERS AND THUNDERSTORMS WILL TAPER OFF FROM NORTH TO SOUTH THIS EVENING AND TONIGHT AS THE FRONT DROPS SOUTH OF NEW YORK STATE. HIGH PRESSURE IS THEN FORECAST TO TRACK EAST ACROSS THE GREAT LAKES FRIDAY AND SATURDAY...BRINGING SEASONABLE TEMPERATURES AND MORE COMFORTABLE HUMIDITY. LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... WITH A FLAT UPPER RIDGE CONTINUING OVER THE CENTRAL GREAT LAKES EARLY IN THE PERIOD A SURFACE HIGH WILL MOVE EAST ACROSS THE LOWER LAKES INCLUDING WESTERN AND CENTRAL NEW YORK. THIS FEATURE WILL BE MOVING EAST BY LATE SUNDAY BUT FAIR WEATHER WILL PERSIST. A BUILDING UPPER RIDGE OVER THE NORTHERN PLAINS IS EXPECTED TO CHANGE THE PATTERN OVER OUR REGION EARLY NEXT WEEK. THE BUILDING RIDGE WILL CREATE A TROUGH WITH INCREASING AMPLITUDE OVER THE NORTHEAST PART OF THE COUNTRY BY MONDAY MORNING. THIS FEATURE WILL CREATE A SURFACE LOW NORTH OF THE ST LAWRENCE VALLEY WITH A TRAILING COLD FRONT SCHEDULED TO MOVE SOUTHEAST ACROSS US MONDAY MORNING. SCATTERED THUNDERSTORMS ARE EXPECTED AS THE FRONT MOVES THROUGH. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT WITH FAIR AND COOLER WEATHER ON TAP FOR TUESDAY AND WEDNESDAY. HIGHS WILL BE IN A COMFORTABLE UPPER 70S RANGE WITH DEW POINTS IN THE UPPER 50S. AVIATION... VFR CEILINGS WILL LOWER TO MVFR FOR AWHILE AS A COLD FRONT DRIFTS SOUTH FROM CANADA. LOCAL IFR VISIBILITY IS POSSIBLE IN HEAVY RAIN IN THUNDERSTORMS. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ UPDATE...RSH ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 931 AM EDT THU AUG 3 2006 .UPDATE... A COOL FRONTAL BOUNDARY WILL SAG ACROSS THE FORECAST AREA THIS AFTERNOON AND TONIGHT AND WILL SERVE TO BE THE FOCUS FOR SOME -SHRA/TSRA. PWATS ARE IN THE RANGE OF 1.75-2.0...SO ANY CONVECTION COULD INCLUDE SOME VERY HEAVY RAIN. WHILE THE WINDS HAVE SHIFTED TO A MORE NORTHWESTERLY DIRECTION FOR MANY OF THE REPORTING SITES AS OF 14Z (BUF, ROC, IAG)...THE ACTUAL COOL FRONT IS STILL TO OUR NORTH. THE VEERING WINDS MAY BE A RESULT OF AN OUTFLOW BOUNDARY OR SOME OTHER MESOSCALE FEATURE. SFC WINDS WILL LIKELY GO BACK TO THE WEST OR SOUTHWEST THIS AFTERNOON AS THE FRONT WILL SLOWLY SETTLE SOUTHWARDS. THERE ARE STILL SEVERAL WAVES ANALYZED ALONG THE FRONT TO OUR WEST TO BELIEVE THAT A STRONG SOUTHWARD PUSH WILL TAKE PLACE ANYTIME REAL SOON. IN ANY CASE...LIKELY POPS WILL REMAIN IN PLACE FOR THE REGION THIS AFTERNOON. THOSE POPS WILL DROP OFF FROM NORTH TO SOUTH DURING THE LATE AFTERNOON AND EVENING...WHEN THE LAST WAVE ALONG THE FRONT WILL CLEAR TO THE NORTHEAST. IN TERMS OF STRONG/SEVERE THUNDERSTORMS...THE SOUTHERN COUNTIES WILL HAVE THE HIGHEST PROBABILITY OF EXPERIENCING ANYTHING SIGNIFICANT. THE AIRMASS IS ALREADY MORE UNSTABLE WELL SOUTH OF BUFFALO AND ROCHESTER AND DIURNAL AFFECTS COULD ADD TO THIS INSTABILITY (THINNER CLOUD COVER TO THE SOUTH) AS THE MIDDAY PROGRESSES. THE SPC SLGHT RIOSK OUTLINE FOR TODAY INCLUDES OUR SOUTHERN TIER AND A PORTION OF THE FINGER LAKES REGION. THE WIND FIELD SCF-10K SHOWS LITTLE SHEAR AT THIS TIME...WITH NEAR UNIDIRECTIONAL FLOW ANTICIPATED TO REMAIN INTACT FOR MUCH OF THE AFTERNOON. THE ONLY SHEAR WILL BE SUPPLIED BY THE 35-40 KT WINDS ABOVE 5K. STRAIGHT LINE WINDS WILL THUS REMAIN THE MAIN THREAT IN TERMS OF SEVERE WEATHER TYPE...AS THE FRZG LEVEL REMAINS ABOVE 16K FEET WITH ONLY MARGINAL SHEAR TO SUPPORT ANY ORGANIZED MESO'S. WOULD NEED TO UTILILIZE ALL OF 2000 J/KG PROJECTED EARLY AFTERNOON CAPES FOR THE SOUTHERN TIER TO HAVE ANY REAL CHANCE OF PRODUCING SIGNIFICANT HAIL. RSH && .PREV DISCUSSION... /ISSUED 642 AM EDT THU AUG 3 2006/ UPDATE... THE ACTIVE CONVECTION THAT IS FIRING UP OVER ILLINOIS AND NORTHERN INDIANA SEEMS TO BE ROBBING SOME OF THE ENERGY FROM THE EASTERN END OF THE COLD FRONT. THE LATEST RUC GUIDANCE AGREES WITH THE EARLIER WRF THAT THE STRONGEST INSTABILITY WILL STAY SOUTH OF OUR CWA. BASED ON THIS TREND...HAVE DECIDED TO DOWNPLAY THE THUNDERSTORMS A BIT IN THE ZFP...BUT WILL LEAVE IN THE WORDING FOR THE POSSIBILITY OF HEAVY RAIN DUE TO THE VERY MOIST AIRMASS THAT IS STILL PLACE ACROSS NEW YORK STATE. PREV DISCUSSION... /ISSUED 344 AM EDT THU AUG 3 2006/ SHORT TERM /TODAY THROUGH SATURDAY/... THE COLD FRONT THAT STRETCHES FROM JUST NORTH OF LAKE ONTARIO TO CENTRAL MICHIGAN WILL DRIFT SLOWLY TO THE SOUTH TODAY AS THE UPPER LEVEL RIDGE CONTINUES TO FLATTEN. ONE AREA OF SHOWERS AND SCATTERED THUNDERSTORMS IS CURRENTLY PUSHING THROUGH WESTERN NEW YORK STATE...WHILE A SECOND BATCH OF CONVECTION IS FIRING UP OVER THE SOUTHERN HALF OF MICHIGAN. THE ONGOING CONVECTION IS NOT AS STRONG AS THAT WHICH AFFECTED PARTS OF THE CWA EARLIER IN THE NIGHT...BUT THE ATMOSPHERE SOUTH OF THE FRONT IS STILL VERY HUMID AND RATHER UNSTABLE. THEREFORE...WILL FOLLOW CONTINUITY AND LEAVE IN LIKELY POPS FOR TODAY. THE LATEST WRF NOW TRACKS THE COLD FRONT SOUTH ACROSS OUR CWA A LITTLE FASTER THAN THE GFS. THE GFS SEEMS MORE REASONABLE CONSIDERING HOW FRONT IS GETTING HUNG UP ALONG THE NORTHERN EDGE OF THE STRONG UPPER RIDGE...AS IS OFTEN THE CASE AT THIS TIME OF THE YEAR. THE MODELS SUGGEST THAT THE MOST UNSTABLE AIR WILL LIE JUST SOUTH OF NEW YORK STATE TODAY (SPC KEEPS THE SLIGHT RISK AREA MAINLY SOUTH OF OUR CWA)...BUT HEAVY RAIN IS A CONCERN AS MOISTURE FROM UPSTREAM CONVECTION CONTINUES TO POOL AHEAD OF THE SLOW MOVING FRONT. THE WRF ALSO SHOWS PRECIPITABLE WATER VALUES APPROACHING 2 INCHES DURING THE MID AFTERNOON. EXPECT AREA TEMPERATURES TO BE 10 TO 15 DEGREES COOLER THAN THE OPPRESSIVE READINGS OF THE FIRST HALF OF THE WEEK...BUT THERE WILL NOT BE A LOT OF RELIEF FROM THE UNCOMFORTABLE CONDITIONS AS HUMIDITY LEVELS WILL STILL REMAIN HIGH. SCATTERED SHOWERS AND THUNDERSTORMS WILL TAPER OFF FROM NORTH TO SOUTH THIS EVENING AND TONIGHT AS THE FRONT DROPS SOUTH OF NEW YORK STATE. HIGH PRESSURE IS THEN FORECAST TO TRACK EAST ACROSS THE GREAT LAKES FRIDAY AND SATURDAY...BRINGING SEASONABLE TEMPERATURES AND MORE COMFORTABLE HUMIDITY. LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... WITH A FLAT UPPER RIDGE CONTINUING OVER THE CENTRAL GREAT LAKES EARLY IN THE PERIOD A SURFACE HIGH WILL MOVE EAST ACROSS THE LOWER LAKES INCLUDING WESTERN AND CENTRAL NEW YORK. THIS FEATURE WILL BE MOVING EAST BY LATE SUNDAY BUT FAIR WEATHER WILL PERSIST. A BUILDING UPPER RIDGE OVER THE NORTHERN PLAINS IS EXPECTED TO CHANGE THE PATTERN OVER OUR REGION EARLY NEXT WEEK. THE BUILDING RIDGE WILL CREATE A TROUGH WITH INCREASING AMPLITUDE OVER THE NORTHEAST PART OF THE COUNTRY BY MONDAY MORNING. THIS FEATURE WILL CREATE A SURFACE LOW NORTH OF THE ST LAWRENCE VALLEY WITH A TRAILING COLD FRONT SCHEDULED TO MOVE SOUTHEAST ACROSS US MONDAY MORNING. SCATTERED THUNDERSTORMS ARE EXPECTED AS THE FRONT MOVES THROUGH. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT WITH FAIR AND COOLER WEATHER ON TAP FOR TUESDAY AND WEDNESDAY. HIGHS WILL BE IN A COMFORTABLE UPPER 70S RANGE WITH DEW POINTS IN THE UPPER 50S. AVIATION... VFR CEILINGS WILL LOWER TO MVFR FOR AWHILE AS A COLD FRONT DRIFTS SOUTH FROM CANADA. LOCAL IFR VISIBILITY IS POSSIBLE IN HEAVY RAIN IN THUNDERSTORMS. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ UPDATE...RSH PREVIOUS UPDATE...TJP SHORT TERM...TJP LONG TERM...SAGE AVIATION...APB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 642 AM EDT THU AUG 3 2006 .UPDATE... THE ACTIVE CONVECTION THAT IS FIRING UP OVER ILLINOIS AND NORTHERN INDIANA SEEMS TO BE ROBBING SOME OF THE ENERGY FROM THE EASTERN END OF THE COLD FRONT. THE LATEST RUC GUIDANCE AGREES WITH THE EARLIER WRF THAT THE STRONGEST INSTABILITY WILL STAY SOUTH OF OUR CWA. BASED ON THIS TREND...HAVE DECIDED TO DOWNPLAY THE THUNDERSTORMS A BIT IN THE ZFP...BUT WILL LEAVE IN THE WORDING FOR THE POSSIBILITY OF HEAVY RAIN DUE TO THE VERY MOIST AIRMASS THAT IS STILL PLACE ACROSS NEW YORK STATE. && .PREV DISCUSSION... /ISSUED 344 AM EDT THU AUG 3 2006/ SHORT TERM /TODAY THROUGH SATURDAY/... THE COLD FRONT THAT STRETCHES FROM JUST NORTH OF LAKE ONTARIO TO CENTRAL MICHIGAN WILL DRIFT SLOWLY TO THE SOUTH TODAY AS THE UPPER LEVEL RIDGE CONTINUES TO FLATTEN. ONE AREA OF SHOWERS AND SCATTERED THUNDERSTORMS IS CURRENTLY PUSHING THROUGH WESTERN NEW YORK STATE...WHILE A SECOND BATCH OF CONVECTION IS FIRING UP OVER THE SOUTHERN HALF OF MICHIGAN. THE ONGOING CONVECTION IS NOT AS STRONG AS THAT WHICH AFFECTED PARTS OF THE CWA EARLIER IN THE NIGHT...BUT THE ATMOSPHERE SOUTH OF THE FRONT IS STILL VERY HUMID AND RATHER UNSTABLE. THEREFORE...WILL FOLLOW CONTINUITY AND LEAVE IN LIKELY POPS FOR TODAY. THE LATEST WRF NOW TRACKS THE COLD FRONT SOUTH ACROSS OUR CWA A LITTLE FASTER THAN THE GFS. THE GFS SEEMS MORE REASONABLE CONSIDERING HOW FRONT IS GETTING HUNG UP ALONG THE NORTHERN EDGE OF THE STRONG UPPER RIDGE...AS IS OFTEN THE CASE AT THIS TIME OF THE YEAR. THE MODELS SUGGEST THAT THE MOST UNSTABLE AIR WILL LIE JUST SOUTH OF NEW YORK STATE TODAY (SPC KEEPS THE SLIGHT RISK AREA MAINLY SOUTH OF OUR CWA)...BUT HEAVY RAIN IS A CONCERN AS MOISTURE FROM UPSTREAM CONVECTION CONTINUES TO POOL AHEAD OF THE SLOW MOVING FRONT. THE WRF ALSO SHOWS PRECIPITABLE WATER VALUES APPROACHING 2 INCHES DURING THE MID AFTERNOON. EXPECT AREA TEMPERATURES TO BE 10 TO 15 DEGREES COOLER THAN THE OPPRESSIVE READINGS OF THE FIRST HALF OF THE WEEK...BUT THERE WILL NOT BE A LOT OF RELIEF FROM THE UNCOMFORTABLE CONDITIONS AS HUMIDITY LEVELS WILL STILL REMAIN HIGH. SCATTERED SHOWERS AND THUNDERSTORMS WILL TAPER OFF FROM NORTH TO SOUTH THIS EVENING AND TONIGHT AS THE FRONT DROPS SOUTH OF NEW YORK STATE. HIGH PRESSURE IS THEN FORECAST TO TRACK EAST ACROSS THE GREAT LAKES FRIDAY AND SATURDAY...BRINGING SEASONABLE TEMPERATURES AND MORE COMFORTABLE HUMIDITY. LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... WITH A FLAT UPPER RIDGE CONTINUING OVER THE CENTRAL GREAT LAKES EARLY IN THE PERIOD A SURFACE HIGH WILL MOVE EAST ACROSS THE LOWER LAKES INCLUDING WESTERN AND CENTRAL NEW YORK. THIS FEATURE WILL BE MOVING EAST BY LATE SUNDAY BUT FAIR WEATHER WILL PERSIST. A BUILDING UPPER RIDGE OVER THE NORTHERN PLAINS IS EXPECTED TO CHANGE THE PATTERN OVER OUR REGION EARLY NEXT WEEK. THE BUILDING RIDGE WILL CREATE A TROUGH WITH INCREASING AMPLITUDE OVER THE NORTHEAST PART OF THE COUNTRY BY MONDAY MORNING. THIS FEATURE WILL CREATE A SURFACE LOW NORTH OF THE ST LAWRENCE VALLEY WITH A TRAILING COLD FRONT SCHEDULED TO MOVE SOUTHEAST ACROSS US MONDAY MORNING. SCATTERED THUNDERSTORMS ARE EXPECTED AS THE FRONT MOVES THROUGH. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT WITH FAIR AND COOLER WEATHER ON TAP FOR TUESDAY AND WEDNESDAY. HIGHS WILL BE IN A COMFORTABLE UPPER 70S RANGE WITH DEW POINTS IN THE UPPER 50S. AVIATION... VFR CEILINGS WILL LOWER TO MVFR FOR AWHILE AS A COLD FRONT DRIFTS SOUTH FROM CANADA. LOCAL IFR VISIBILITY IS POSSIBLE IN HEAVY RAIN IN THUNDERSTORMS. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ UPDATE...TJP ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 926 PM CDT THU AUG 3 2006 .UPDATE... MAIN UPDATE CHALLENGE IS WEAK CONVECTIVE POTENTIAL AFTER MIDNIGHT TONIGHT AND CONTINUING INTO THE MORNING HOURS ON FRI. RUC AND NEW 00Z NAM PRETTY CONSISTENT IN DEVELOPING A 40-50KT LOW LEVEL JET AFTER MIDNIGHT IN THE CENTRAL DAKOTAS AND SHIFTING IT INTO EASTERN ND TOWARD 12Z FRI. 18Z GFS NOT THAT FAR OFF EITHER. EVEN LOOKING AT THE LATEST RUN OF THE UKMET WOULD JUSTIFY ADDING A SMALL CHANCE OF TSTMS FOR WEST OF THE RED RIVER VALLEY FOR LATE TONIGHT. DEEP MOISTURE IS LACKING...BUT THE MODELS DO SHOW A THIN RIBBON OF 850MB MOISTURE. 850MB TEMP ADVECTION A BIT HARDER TO NAIL DOWN AS MODELS SEEM TO SHOW THE STRONGEST WARM ADVECTION ALONG THE CANADIAN BORDER. HOWEVER...THERE IS SOME WEAK WARM ADVECTION ON THE NOSE OF THE LOW LEVEL JET TOO. ALSO EXTENDED THE SMALL CHANCE OF TSTMS INTO THE MORNING ON FRI FOR ALL AREAS. OVERALL COVERAGE WILL BE MINIMAL AS WELL AS AMOUNTS. CLEAR SKIES ATTM WILL GIVE WAY TO MORE CLOUDS LATE AS WELL. WILL STAY CLEAREST FOR THE MOST TIME IN THE NORTHEAST FA...SO DID DROP LOW TEMPS A FEW MORE DEGREES THERE. && .PREV DISCUSSION... (ISSUED 225 PM CDT THU AUG 3 2006) CURRENT OBSERVATIONAL OVERVIEW... 18Z SURFACE ANALYSIS DEPICTED RIDGE AXIS FROM ALBERTA PROVINCE TO NORTH DAKOTA WHILE TROUGH OF LOW PRESSURE WAS SITUATED ACROSS CENTRAL MONTANA WITH ASSOCIATED WARM FRONT DRAPED EAST ACROSS NORTH/SOUTH DAKOTA BORDER. LATEST WATER VAPOR IMAGERY SHOWED PROGRESSIVE/ACTIVE ZONAL MEAN 500MB FLOW ACROSS NORTHERN HALF OF CONUS WITH EMBEDDED SHOTS OF SHORTWAVE ENERGY TRANSVERSING EASTWARD IN FLOW. SHORT TERM (TONIGHT-SUNDAY)... MAIN FORECAST CHALLENGE THROUGH PERIOD WILL CENTER ON PERIODIC CONVECTIVE CHANCES WITH WARM FRONT TONIGHT/FRIDAY AND THEN FROPA ON SATURDAY. USED GFS SOLUTION AS THE PRIMARY MODEL TOOL IN FORECAST WITH MODEL DOING A GOOD JOB WITH RESPECT TO SURFACE/UPPER LEVEL FEATURES WITH CURRENT 18Z DATA FIELDS. WILL KEEP LOW POP THREAT ACROSS THE DEVILS LAKE BASIN LATE TONIGHT WITH COMMENCEMENT OF 850MB WAA/THETA-E ADVECTION PATTERN. FEEL ONLY LOW POP JUSTIFIED WITH LACK OF DEEP LAYERED MOISTURE PROFILE. ON FRIDAY APPEARS MAIN THUNDER THREAT WILL BE CONFINED MORE TO THE EVENING AND OVERNIGHT HOURS AS WARM FRONT DRAPED ACROSS NORTHERN HALF OF CWFA INTERACTS WITH FAIRLY POTENT NOCTURNAL 850MB LOW LEVEL JET. BASED ON ORIENTATION OF WARM FRONT APPEARS NORTHERN COUNTIES/BORDERING THE U.S. INTERNATIONAL BORDER AT GREATEST RISK. CONVECTIVE THREAT SHIFTS GEARS TO MORE CWFA AREA-WIDE EVENT ON SATURDAY AS FAIRLY SIGNIFICANT COLD FRONT SWEEPS SOUTHEAST ACROSS CWFA. BASED ON CURRENT TIMING OF FRONT IT APPEARS BEST THUNDER THREAT WILL BE FROM THE VALLEY EAST SATURDAY AFTERNOON/EVENING. CONVECTIVE PARAMETERS POOLING AHEAD OF FRONT SHOULD AT LEAST BE IN THE MODERATE CATEGORY WITH FAIRLY ROBUST SHOWALTER/SFC BASED COMPUTED LI'S/ML CAPES IN EXCESS OF 2000 J/KG. ONLY POSSIBLE HINDRANCE TO EVENT IS POTENTIAL CAPPING ISSUES HOWEVER IT APPEARS MID-LEVEL COOLING WITH S/W AND INCREASING CONVERGENCE WITH FRONT SHOULD HELP TO ERODE ANY CAP THAT MIGHT EXIST. IN WAKE OF FRONT DRIER AND COOLER WILL WORK INTO THE CWFA SUNDAY. LONG TERM (MON-THU)...MODELS IN GOOD AGREEMENT WITH SFC HIGH PRESSURE PROPAGATING THROUGH THE REGION AS 500MB RIDGE BUILDS ACROSS THE CENTRAL CONUS. MAIN CHALLENGE WILL COME WED-THU AS THE SFC HIGH MOVES E AND SHORTWAVES MOVING AROUND THE RIDGE AFFECT THE REGION. WITH MOISTURE RETURN STILL VERY QUESTIONABLE...SHORTWAVE TIMING DIFFICULT...AND UPPER RIDGE IN PLACE WILL KEEP FORECAST DRY. AT THIS TIME WILL ONLY INCREASE CLOUD COVER. THIS WEATHER PATTERN SHOULD GIVE ABOVE NORMAL TEMPERATURES. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ GODON nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BISMARCK ND 922 PM CDT THU AUG 3 2006 .UPDATE...A FEW MINOR TWEAKS THIS EVENING. FIRST TO ADJUST EVENING TEMPERATURES AND DEWPOINTS...MAINLY IN THE WEST AS TEMPERATURES ARE SLOWER TO COOL OFF EARLY THIS EVENING...AND LOW DEW POINTS ARE HOLDING ON IN THE FAR WEST. SECOND...WILL TWEAK POPS A BIT. THE CONVECTION IN THE NORTHWEST BARELY HOLDING ON...BUT SHOULD BE OUT OF THAT AREA IN A COUPLE HOURS. EXTENDED POPS LATE TONIGHT THROUGHOUT THE SOUTHEAST CWA...ADJACENT TO FGF. 18Z GFS AND EVEN MORE SO THE LATEST RUC INDICATE A STRONG LOW LEVEL JET DEVELOPING OVER SOUTH CENTRAL/SOUTHEAST NORTH DAKOTA OVERNIGHT. && .PREVIOUS DISCUSSION... .SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT FORECAST CONCERNS/HIGHLIGHTS IN THE SHORT TERM WILL BE PRECIPITATION CHANCES TONIGHT THROUGH SATURDAY AFTERNOON...TEMPERATURES...AND POSSIBLE FIRE WEATHER CONCERNS TOMORROW AND PERHAPS SATURDAY. CURRENTLY...HIGH PRESSURE NORTH WITH LOW PRESSURE DEVELOPING WEST UNDER QUASI ZONAL FLOW ALOFT. SOME SCT TO BKN MID LEVEL CLOUDS SOUTH CENTRAL AND SCT-BKN CU DEVELOPING WEST. TONIGHT...SURFACE LOW PRESSURE WEST DEVELOPS FURTHER OVER THE HIGH PLAINS. ATMOSPHERIC INSTABILITY AND A WEAK MID LEVEL WAVE OVER THE FORECAST AREA...SO WILL INTRODUCE SLIGHT CHANCE THUNDER OVER ALL AREAS...WITH SCT POPS NORTH WHERE THE BEST LIFT SHOULD BE IN PROXIMITY TO THE SURFACE LOW. MODELS ALSO DEPICTING DECENT MOISTURE ADVECTION INTO THE NORTHERN PLAINS TO HELP AID THUNDER POTENTIAL. FOR TOMORROW AND TOMORROW NIGHT...WILL LEAVE IN SLIGHT CHANCE TO CHANCE POPS WITH CONTINUED UNSTABLE AIR AND AS THE SURFACE TROUGH PROGRESSES EAST. NO SEVERE MENTION IN ZONES THIS PACKAGE...BUT COULD SEE A FEW STRONG STORMS. GOOD SOUTHERLY FLOW WILL HELP TRANSPORT HOT TEMPERATURES INTO THE REGION FRIDAY...WITH UPPER 90S TO AROUND 100 SOUTHWEST AND SOUTH CENTRAL EXPECTED. WILL ISSUE FIRE WEATHER WATCH SOUTH CENTRAL FOR TOMORROW AFTERNOON FOR LOW RH VALUES AND BREEZY SOUTH WINDS AHEAD OF THE TROUGH. SEE FIRE WEATHER DISCUSSION BELOW FOR DETAILS. PRECIPITATION/THUNDERSTORM CHANCES CONTINUE INTO SATURDAY DAYTIME CENTRAL AND EAST ALONG AND AROUND THE TROUGH/COLD FRONT WHERE THE BEST INSTABILITY WILL BE. WINDS WILL ALSO BE ON THE BREEZY SIDE SATURDAY FROM THE NORTHWEST AFTER THE TROUGH PASSES...POSSIBLY CREATING ANOTHER DAY OF FIRE WEATHER ISSUES...THIS TIME OVER THE WESTERN FIRE WEATHER ZONES. PRECIPITATION WILL END BY THE LATE AFTERNOON EAST AS THE TROUGH MOVES INTO MINNESOTA. TEMPERATURES WILL BE MUCH COOLER BEHIND THE TROUGH SATURDAY AND WILL CONTINUE INTO SUNDAY BEFORE WAA RETURNS SUNDAY NIGHT INTO MONDAY. .LONG TERM...MONDAY THROUGH THURSDAY NIGHT UPPER RIDGE WILL BUILD INTO THE ROCKIES THIS WEEKEND WITH GENERAL TROUGHING IN THE EASTERN US BY MONDAY MORNING. SFC HIGH PRESSURE WILL SLIDE SOUTHEAST INTO THE WESTERN MIDWEST MONDAY INTO TUESDAY...ALLOWING CAA TO DOMINATE THE GREAT LAKES REGION...AS GENERAL WAA WILL ALLOW WARMER TEMPS IN THE NORTHERN PLAINS. THIS WOULD TEND TO SUPPORT WESTERN RIDGING AND EASTERN TROUGHING. ECMWF AND GFS IN GOOD AGREEMENT...WITH CANADIAN THE ONLY OUTLIER...IN BRINGING UPPER LEVEL RIDGE EAST SLIGHTLY FASTER. ABOVE NORMAL TEMPS LOOK CERTAIN...GIVEN DRY CONDITIONS ALREADY PRESENT. GFS STILL HINTS AT DESCENT MOISTURE ADVECTION FROM THE SOUTHEAST...TUESDAY INTO WEDNESDAY...AHEAD OF ADVERTISED DISTURBANCE IN THE TUESDAY NIGHT INTO WEDNESDAY EVENING TIME FRAME. HOWEVER...GIVEN DRY CONDITIONS FARTHER SOUTH...THIS SOLUTION MAY BE OVERDONE. GENERALLY...MODELS INDICATE UPPER LEVEL RIDGE WILL SHIFT EAST BY MID NEXT WEEK...ALLOWING SEVERAL SHORTWAVES TROUGHS TO PROPAGATE THROUGH THE REGION. THIS MAY MEAN AN ACTIVE PRECIP PATTERN IF LOW LEVEL MOISTURE CAN BUILD INTO THE REGION. ONLY ADJUSTED TEMPS SOME...AND EXTENDED LOW PRECIP CHANCES INTO MONDAY MORNING LATER WITH STRONG WAA. DID NOT FEEL TO CONFIDENT IN ADDING ANY OTHER PRECIP CHANCES AT THIS TIME...AS MOISTURE ADVECTION...TROUGH TIMING AND RIDGE LOCATION ARE ALL UNCERTAIN. && .FIRE WEATHER... A SURFACE LOW PRESSURE TROUGH WEST OF THE REGION WILL CONTINUE TO DEVELOP TONIGHT...PUSHING EAST TOMORROW INTO THE WESTERN FORECAST AREA. AHEAD OF THE TROUGH...BREEZY SOUTHERLY WINDS ARE EXPECTED OVER CENTRAL NORTH DAKOTA...ALONG WITH VERY WARM TEMPERATURES. DEW POINT TEMPERATURES ARE NOT EXPECTED TO INCREASE UNTIL LATER TOMORROW NIGHT...RESULTING IN AFTERNOON RELATIVE HUMIDITY VALUES AROUND 15 PERCENT SOUTHWEST AND SOUTH CENTRAL. IN ADDITION...ISOLD TO SCATTERED THUNDERSTORMS ARE ALSO FORECASTED...BRINGING A THREAT OF DRY LIGHTNING TO ANY STORM THAT DEVELOPS. HENCE A FIRE WEATHER WATCH HAS BEEN ISSUED FOR CENTRAL AND SOUTH CENTRAL NORTH DAKOTA MAINLY DUE TO BREEZY SOUTHERLY WINDS AND LOW RH VALUES. A RED FLAG WARNING MAY BE NEEDED FOR ALL OR PORTIONS OF THE WATCH AREA. ON SATURDAY...BREEZY TO GUSTY NORTHWEST WINDS WILL DEVELOP BEHIND THE SURFACE TROUGH AS IT PUSHES EAST INTO EASTERN NORTH DAKOTA. DEPENDING PRIMARILY ON AFTERNOON RELATIVE HUMIDITY VALUES...A FIRE WEATHER WATCH OR RED FLAG WARNING MAY BE NEEDED ACROSS THE WESTERN FIRE WEATHER ZONES. && .BIS WATCHES/WARNINGS/ADVISORIES... FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR NDZ019-NDZ020-NDZ021-NDZ034-NDZ035-NDZ036-NDZ042-NDZ045- NDZ046-NDZ047-NDZ050. && $$ TWH nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 847 PM EDT THU AUG 3 2006 .SHORT TERM (REST OF TONIGHT THROUGH FRIDAY)... BASED ON RECENT SURFACE AND RADAR DATA, IN CONJUNCTION WITH LATEST RUC AND NAM-WRF MODEL SOLUTIONS, EXPECT CURRENT BANDS OF SHOWERS AND THUNDERSTORMS TO DECREASE IN COVERAGE OVERNIGHT. SOME GUSTY WIND AND HEAVY RAIN STILL POSSIBLE. AS LOWLEVEL AIRMASS CAN BECOME SATURATED BY RECENTLY WETTED GROUNDS ALONG WITH RESIDUAL ATMOSPHERIC HUMIDITY, PATCHY FOG CAN DEVELOP AROUND DAYBREAK. AS SURFACE COLD FRONT CONTINUES TO MOVE SOUTHWARD THROUGH THE UPPER OHIO VALLEY AND APPALACHIAN MOUNTAINS FRIDAY, EXPECT RAIN POTENTIAL TO END AS HUMIDITY LEVELS FURTHER DECREASE. ADJUSTED TEMPERATURES DOWN A COUPLE DEGREES PER RECENT READINGS AND EVAPORATIONAL EFFECTS OF RECENTLY WETTED GROUNDS. && .PREVIOUS DISCUSSION... (ISSUED 303 PM EDT THU AUG 3 2006) SHORT TERM (TODAY THROUGH FRIDAY)... BASED ON RECENT RUC, NAM WRF, AND GFS MODEL RUNS, EXPECT TWO OR THREE BANDS OF PREFRONTAL THUNDERSTORMS TO MOVE SOUTHEASTWARD ACROSS THE UPPER OHIO VALLEY TONIGHT. THE MAIN THREAT WILL BE DAMAGING WIND. LOCAL RAIN AMOUNTS CAN GO OVER 1 OR 2 INCHES. FLASH FLOOD GUIDANCE IS 2-2.5 INCHES IN 3 HOURS. THE COLD FRONT WILL BEGIN TO LOWER THE MOISTURE CONTENT FRIDAY AND TEMPERATURES WILL NOT BE WARM AS PREVIOUS DAYS AS NAM AND GFS MOS VALUES SHOW. LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)... COOLER WEATHER WILL INVADE THE REGION AFTER THE FRONT PUSHES THROUGH ON FRIDAY. THIS WILL GIVE A COMFORTABLE WEEKEND WITH LITTLE PRECIPITATION EXPECTED. THE NEXT CHANCE OF PRECIP SHOULD BE SUNDAY NIGHT AS ANOTHER WAVE IS FORECAST TO PUSH IN FROM THE WEST. AVIATION... BASED ON RECENT RADAR DATA AND RUC AND NAM WRF MODEL RUNS, EXPECT THE FIRST BAND OF SCATTERED THUNDERSTORMS TO MOVE THROUGH THE UPPER OHIO VALLEY 18Z-21Z. FROM A CONSENSUS OF RUC AND NAM WRF MODEL RUNS, EXPECT ANOTHER BAND OF THUNDERSTORMS TO MOVE THROUGH THE UPPER OHIO VALLEY BETWEEN 01Z-06Z. HOWEVER, CONSIDERING CLIMATOLOGY, WOULD NOT BE SURPRISED IF THERE IS AN INTERVENING BAND OF SCATTERED THUNDERSTORMS IN THE TIME FRAME OF 21Z-00Z. THE FIRST TWO BANDS OF STORMS HAVE MORE POTENTIAL TO BE SEVERE WITH DAMAGING WIND GUSTS. THE LAST BAND HAS MORE POTENTIAL FOR HEAVY RAIN. THE PREVAILING CLOUD BASES WILL BE BKN050 CUMULUS WITH VISIBILITIES UNRESTRICTED. IN THUNDERSTORMS, FLIGHT CONDITIONS CAN DETERIORATE TO 3SM TSRA BR OVC020CB WITH LOCALIZED BRIEF IFR CONDITIONS POSSIBLE. BY EARLY FRIDAY MORNING, 08Z, THE THUNDERSTORMS SHOULD BE PRETTY MUCH GONE, HOWEVER, SOME FOG AND STRATUS MAY DEVELOP (3SM BR BKN020). BY 14Z, CONDITIONS WILL IMPROVE TO P6SM BKN040 CUMULUS. WINDS WILL BE GENERALLY WESTERLY THIS EVENING AND THEN VEER (TURN CLOCKWISE) INTO THE NORTHWEST LATER TONIGHT AND FRIDAY. SPEEDS CAN BE 10-20KTS THIS AFTERNOON AND ISOLATED THUNDERSTORM WIND GUSTS CAN GO OVER 50KTS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 303 PM EDT THU AUG 3 2006 .SHORT TERM (TODAY THROUGH FRIDAY)... BASED ON RECENT RUC, NAM WRF, AND GFS MODEL RUNS, EXPECT TWO OR THREE BANDS OF PREFRONTAL THUNDERSTORMS TO MOVE SOUTHEASTWARD ACROSS THE UPPER OHIO VALLEY TONIGHT. THE MAIN THREAT WILL BE DAMAGING WIND. LOCAL RAIN AMOUNTS CAN GO OVER 1 OR 2 INCHES. FLASH FLOOD GUIDANCE IS 2-2.5 INCHES IN 3 HOURS. THE COLD FRONT WILL BEGIN TO LOWER THE MOISTURE CONTENT FRIDAY AND TEMPERATURES WILL NOT BE WARM AS PREVIOUS DAYS AS NAM AND GFS MOS VALUES SHOW. && .LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)... COOLER WEATHER WILL INVADE THE REGION AFTER THE FRONT PUSHES THROUGH ON FRIDAY. THIS WILL GIVE A COMFORTABLE WEEKEND WITH LITTLE PRECIPITATION EXPECTED. THE NEXT CHANCE OF PRECIP SHOULD BE SUNDAY NIGHT AS ANOTHER WAVE IS FORECAST TO PUSH IN FROM THE WEST. && .AVIATION... BASED ON RECENT RADAR DATA AND RUC AND NAM WRF MODEL RUNS, EXPECT THE FIRST BAND OF SCATTERED THUNDERSTORMS TO MOVE THROUGH THE UPPER OHIO VALLEY 18Z-21Z. FROM A CONSENSUS OF RUC AND NAM WRF MODEL RUNS, EXPECT ANOTHER BAND OF THUNDERSTORMS TO MOVE THROUGH THE UPPER OHIO VALLEY BETWEEN 01Z-06Z. HOWEVER, CONSIDERING CLIMATOLOGY, WOULD NOT BE SURPRISED IF THERE IS AN INTERVENING BAND OF SCATTERED THUNDERSTORMS IN THE TIME FRAME OF 21Z-00Z. THE FIRST TWO BANDS OF STORMS HAVE MORE POTENTIAL TO BE SEVERE WITH DAMAGING WIND GUSTS. THE LAST BAND HAS MORE POTENTIAL FOR HEAVY RAIN. THE PREVAILING CLOUD BASES WILL BE BKN050 CUMULUS WITH VISIBILITIES UNRESTRICTED. IN THUNDERSTORMS, FLIGHT CONDITIONS CAN DETERIORATE TO 3SM TSRA BR OVC020CB WITH LOCALIZED BRIEF IFR CONDITIONS POSSIBLE. BY EARLY FRIDAY MORNING, 08Z, THE THUNDERSTORMS SHOULD BE PRETTY MUCH GONE, HOWEVER, SOME FOG AND STRATUS MAY DEVELOP (3SM BR BKN020). BY 14Z, CONDITIONS WILL IMPROVE TO P6SM BKN040 CUMULUS. WINDS WILL BE GENERALLY WESTERLY THIS EVENING AND THEN VEER (TURN CLOCKWISE) INTO THE NORTHWEST LATER TONIGHT AND FRIDAY. SPEEDS CAN BE 10-20KTS THIS AFTERNOON AND ISOLATED THUNDERSTORM WIND GUSTS CAN GO OVER 50KTS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 950 PM CDT THU AUG 3 2006 .DISCUSSION... SFC ANALYSIS SHOWED A COLD FRONT STRETCHED SOUTHWEST TO NORTHEAST ACROSS THE OHIO RIVER VALLEY AT 02Z. THUNDERSTORMS WERE OBSERVED IN VICINITY OF THIS FRONT ACROSS WESTERN SECTIONS OF KENTUCKY. SINCE ALL THE PRECIPITATION ASSOCIATED WITH THE FRONT WAS LOCATED VERY CLOSE TO THE FRONTAL BOUNDARY ITSELF, AREAS FURTHER SOUTH IN MIDDLE TENNESSEE REMAINED DRY. LATEST RUC MODEL FORECASTS GOOD DEEPENING OF ATMOSPHERIC MOISTURE OVER ABOUT THE NORTHERN ONE HALF OF OUR FORECAST AREA BY 12Z. WITH WEAK SURFACE FRONT CUTTING INTO THE AREA AS THE NIGHT WEARS ON, BELIEVE WE SHOULD GET ENOUGH LIFT IN THE LOW LEVELS TO ALLOW FOR SCATTERED SHOWERS AND THUNDERSTORMS IN AREAS GENERALLY ALONG AND NORTH OF I 40. THEREFORE, WILL RAISE POPS A LITTLE (T0 30%) IN THOSE LOCATIONS FOR THE REMAINDER OF THE NIGHT. OTHERWISE, LITTLE CHANGE TO PREVIOUS FORECAST. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 19 tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1158 AM EDT THU AUG 3 2006 .SHORT TERM /REST OF TODAY/... HEAT INDEX VALUES TO EXCEED 110 DEGRESS THIS AFTERNOON. GOING FORECAST ON TEMPS AND DEW PTS ON TRACK. WAL 12Z SOUNDING SHOWING LESS DRY AIR AT MID LVLS THAN YSTRDY AIDING TO MORE INSTABILITY. LATEST RUC SHOWING PRECIP TO DVLP OVER THE EASTERN HALF OF THE CWA BY 18Z. NAM AND GFS IS NOT. Q-VECTOR CONVERGENCE ON THE 12Z NAM AT H92-H85 SHOWING WIND CONVERGENCE BOUNDARY TO DVLP N OF I-64 THIS AFTN. SCT CU WILL DVLP THIS AFTN OVER THE CWA AND THE BIG QUESTION IS THERE ENOUGH OF A TRIGGER TO ENHANCE CU ENOUGH TO SUPPORT AN ISOL SHRA/TSRA. CONV TEMP AT WAL IS 95 DEGREES TODAY AND CURRENT OBS CLOSE TO THAT...SO CU SHOULD START TO DVLP SHORTLY. FURTHER SOUTH ON VSBY SAT...CU IS ALREADY DVLPG JUST SW OF THE CWA AND ANOTHER WIND CONVERGENCE BOUNDARY DVLPG SOUTH OF A FVX TO ORF LINE. WITH ALL THIS IN MIND...WILL ADD A 20 POP FOR AN ISOL SHRA/TSRA OVER THE CWA TO DVLP DURING THE AFTN/EARLY EVE HRS. THE THREAT OF ANY ACTIVITY THAT DOES DVLP (MOST AREAS WILL REMAIN DRY) WILL END BY LATE EVE AFTER DAYTIME HEATING AND SKIES SHOULD CLEAR OUT WITH HAZE ONCE AGAIN DVLPG TWRDS MORNING. && .PREV DISCUSSION... (ISSUED 237 AM EDT THU AUG 3 2006) SHORT TERM /TODAY THROUGH FRIDAY/... ANOTHER HOT DAY ON TAP FOR TODAY. YET ANOTHER EXCESSIVE HEAT WARNING IN EFFECT FOR TODAY...AS WE'RE ON THE FINAL STRETCH HERE FOR THIS STAGNANT LEE SIDE TROUGH PATTERN. ONLY MINOR TWEAKS TO FORECAST. REFRESHED TEMPS WITH LATEST GUIDANCE. AND AS USUAL TEMPS AND DW PTS ARE RUNNING A FEW DEGREES TOO HIGH...ESP THE MAV. AGAIN TODAY TOOK A GOOD BLEND OF ALL GUIDANCE AND DID NOT HAVE TO MAKE ANY ADJUSTMENTS...EXCEPT DECREASED KSBY DUE TO PERSISTENCE FORECASTING. TEMPS FOR FRIDAY WERE BUMPED UP A FEW DEGREES UPON LOADING IN A BLEND OF ALL GUIDANCE AS DONE FOR TODAY. DO NOT HAVE A PROBLEM WITH THIS SINCE SKY COVER SHOULD NOT BE COMPLETELY DENSELY OVERCAST AND A LOT OF DAYTIME HEATING COULD OCCUR BEFORE FRONTAL BOUNDARY CLOSES IN ON OUR AREA. ALREADY HAVE GONE WITH HEAT ADVISORY FOR FRI SINCE TEMPS WILL NOT BE IN THE 3 DIGIT RANGE. CONDITIONS STILL VERY HOT HOWEVER AND PRECAUTIONS SHOULD BE TAKEN TO KEEP COOL THROUGH FRIDAY. (SEE WBCNPWAKQ FOR MORE INFO ON HEAT ADVISORY AND EXCESSIVE HEAT WARNINGS.) LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... WITH FRONTAL PASSAGE FRIDAY AFTERNOON EXPECT CHC FOR STRONG THUNDERSTORMS ACROSS THE AREA. APPEARS AS BOUNDARY STALLS OVER NC/VA BOUNDARY...WHICH I AGREE WITH PREVIOUS FORECASTER IS NOT UNCOMMON DURING THIS TIME OF YEAR. A LOT OF FAST MOVING SHORT WAVES MOVE THOUGH THE AREA OVER THE WEEKEND INTO EARLY NEXT WEEK. LOOK FOR MAINLY DIURNAL CHC FOR SHOWERS/THUNDERSTORMS. HIGH PRESSURE DOENS'T MAKE IT INTO OUT REGION UNTIL MID WEEK NEXT WEEK. AVIATION... PREDAWN IFR/TEMPO LIFR LIKELY IN FOG ESPECIALLY AT ECG/SBY. OTHERWISE...PERSISTENCE A GOOD FCST IN THIS STAGNANT AIRMASS. HAZE WILL CONTINUE TO CAUSE VSBY RESTRICTIONS TODAY...MAINLY INTO THE MVFR RANGE. MARINE... NOCTURNAL JETTING HAS CAUSED AN INCREASE IN SW WINDS EARLY THIS MORN. SPEEDS TOPPING OUT AROUND 15KT AND SHOULD BEGIN TO SHOW DECREASING TREND AS BNDRY LAYER BECOMES MORE STABLE TOWARD SUNRISE. A CONTINUATION OF THE LIGHT TO OCCASIONALLY MODERATE SW FLOW CONTS TODAY AND INTO TONIGHT BEFORE SFC BNDRY SAGS INTO MARINE AREA ON FRIDAY. WINDS TURNING N THEN NE AND E AS FRONT DROPS THRU AND BECOMES STATIONARY SOMEWHERE OFF NRN OUTER BANKS ON SATURDAY. CLIMATE... GOOD CHANCE FOR SOME RECORDS TO BE SET TODAY. CURRENT RECORD HIGHS FOR THURSDAY... THU 8/3 RIC 99 (1987) ORF 101 (1980) SBY 96 (1995) ECG 99 (1980) WAL 93 (1987) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...EXCESSIVE HEAT WARNING FOR MDZ021>025 UNTIL 8 PM THURSDAY. ...HEAT ADVISORY FOR MDZ021>025 FROM 11 AM FRIDAY TO 8 PM FRIDAY. NC...EXCESSIVE HEAT WARNING FOR NCZ012>017-030>032-102 UNTIL 8 PM THURSDAY. ...HEAT ADVISORY FOR NCZ012>017-030>032-102 FROM 11 AM FRIDAY TO 8 PM FRIDAY. VA...EXCESSIVE HEAT WARNING FOR VAZ048-049-060>100 UNTIL 8 PM THURSDAY. ...HEAT ADVISORY FOR VAZ048-049-060>100 FROM 11 AM FRIDAY TO 8 PM FRIDAY. MARINE...NONE. && $$ SHORT TERM...WAMSLEY va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 220 AM MDT FRI AUG 4 2006 .DISCUSSION...FORECAST CONCERNS ARE ON TEMPERATURES AND PRECIPITATION CHANCES THE NEXT SEVERAL DAYS. TODAY/TONIGHT...LIGHT TO MODERATE SHOWERS HAVE FINALLY DEVELOPED WITHIN THE PAST HOUR ACROSS THE SOUTH AND SOUTHEAST PORTIONS OF THE FORECAST AREA WHERE DEEPER 700-500 MOISTURE AND SOME WEAK LIFT IS NOTED BY THE RUC. 06Z NAM QPF HAS A GOOD HANDLE ON CURRENT ACTIVITY WHEN COMPARED TO RADAR SO HAVE RUN WITH IT FOR THE FIRST PERIOD POP/WX GRIDS. AS THIS FEATURE MOVES THROUGH THE CENTRAL AND EASTERN PARTS OF THE FORECAST AREA THIS MORNING AND AFTERNOON ANOTHER WILL ROTATE TOWARD THE FRONT RANGE LATE IN THE DAY. NOT A LOT IN THE WAY OF CONVECTIVE INHIBITION TODAY WITH SOME CAPE AVAILABLE. MID LEVEL LAPSE RATES/LIFT NOTHING TO WRITE ABOUT. THINGS SHOULD DIE OFF QUICKLY WITH THE LOSS OF DAYTIME HEATING SO NO POPS/WX TO WORRY ABOUT. SATURDAY/SATURDAY NIGHT...AN UPPER LEVEL LOW WILL MOVE EAST ALONG THE US/CANADIAN BORDER SATURDAY AFTERNOON ITS TROUGH AXIS AND ASSOCIATED COLD FRONT MOVING INTO PORTIONS OF THE AREA. THE EXACT LOCATION OF THE FRONT WILL BE CRUCIAL TO WHERE AFTERNOON THUNDERSTORMS DEVELOP. RIGHT NOW IT APPEARS THE NORTHWEST 1/3-1/4 OF THE AREA WOULD HAVE THE BETTER CHANCE OF AFTERNOON PRECIPITATION. CURRENT FORECAST HAS SOME SLIGHT CHANCE POPS GOING SO ONLY MODIFICATIONS WILL BE TWEAKING AND INCREASING COVERAGE A BIT ACROSS SOME NORTHWEST KANSAS AND SOUTHWEST NEBRASKA COUNTIES. THE FRONT AND ASSOCIATED AXIS OF MID LEVEL MOISTURE DOESNT MOVE MUCH SATURDAY NIGHT AND CURRENT FORECAST HAS THIS LINED OUT PRETTY WELL. ONLY SLIGHT ADJUSTMENTS NEED TO BE MADE. SUNDAY/SUNDAY NIGHT...MID LEVEL MOISTURE AXIS REMAINS ACROSS THE COLORADO FRONT RANGE AND POINTS WEST WHERE CHANCES OF AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. CURRENT GRIDS HAVE SLIGHT CHANCE POPS FOR FAR EASTERN COLORADO WHICH MATCH WELL WITH BETTER MOISTURE AND 0-6KM WINDS FROM THE SOUTHWEST. SO...WILL LEAVE THESE GRIDS AS IS. THE ABOVE MENTIONED MOISTURE AXIS PUSHES INTO THE NORTHWEST 1/3 OR SO OF THE FORECAST AREA AND GFS/NAM GENERATE SOME LIGHT QPF. WILL GO AHEAD AND ADD SOME SLIGHT CHANCE POPS IN THIS AREA AS A RESULT. MONDAY-TUESDAY...UPPER PATTERN DOESNT CHANGE A WHOLE LOT FROM PREVIOUS DAYS AS HIGH PRESSURE REMAINS ACROSS THE CENTRAL PLAINS. AXIS OF MID LEVEL MOISTURE REMAINS ACROSS THE NORTHWEST 1/2 OF THE AREA OR SO...MOST FAVORABLE IN THE FAR NORTHWEST. THIS IS WHERE BETTER CHANCES OF PRECIPITATION WILL BE POSSIBLE. WILL KEEP HIGHEST SILENT POPS ACROSS THIS AREA. 850 TEMPERATURES FROM THE GFS/ECMWF FAVOR HIGHS CLOSE TO LATEST MEX GUIDANCE SO WILL UP CURRENT FORECAST A FEW DEGREES. WEDNESDAY-THURSDAY...UPPER HIGH REMAINS IN PLACE AND 850 TEMPERATURES AT OR SLIGHTLY ABOVE 30C ACROSS THE AREA. 90S AND A FEW 100S EXPECTED AND HAVE INCREASED PREVIOUS FORECAST TEMPERATURE GRIDS A BIT MORE GIVEN THE GOOD CONSISTENCY AND LATEST MEX GUIDANCE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 418 AM EDT FRI AUG 4 2006 .DISCUSSION... MAIN FCST CONCERNS ARE POTENTIAL OF SHRA/TSRA TONIGHT/EARLY SAT AND SAT NIGHT INTO SUN. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW LOW AMPLITUDE TROFFING FROM THE GREAT LAKES TO NEW ENGLAND...WEAK RIDGING OVER THE NRN PLAINS INTO SCNTRL CANADA AND ANOTHER TROF OVER SW CANADA INTO THE PACIFIC NW. SHRA/TSRA WERE DEVELOPING AHEAD OF THE WRN TROF ACROSS NE MT/NRN ND/SRN SASKATCHEWAN. FARTHER UPSTREAM...MIDLEVEL LOW OVER CNTRL/NRN BRITISH COLUMBIA PER WATER VAPOR IMAGERY/00Z RAOBS WILL BE THE MOST IMPORTANT FEATURE TO AFFECT THE WEATHER HERE IN THE NEXT FEW DAYS. CLOSER TO HOME...SUBTLE SHORTWAVE TRACKING ACROSS WI/UPPER MI PRODUCED A FEW SHRA/ISOLD TSRA EARLIER IN THE EVENING FROM SW UPPER MI/NRN WI TO NRN LAKE SUPERIOR. LAST OF THE -SHRA/SPRINKLES EXITED THE SRN FCST AREA AROUND 05Z...LEAVING BEHIND MOSTLY CLEAR SKIES. WAA PATTERN WILL BEGIN TO DEVELOP INTO UPPER MI THIS AFTN WITH STRONGEST WAA TARGETING NRN MN/ADJACENT ONTARIO. ISENTROPIC ASCENT AS VIEWED ON 305K SFC IS ACTUALLY QUITE STRONG TO THE NW LATE THIS AFTN...PARTICULARLY IN THE NAM WHICH HAS 30-40KT FLOW DIRECTED PERPENDICULAR TO TIGHTLY PACKED ISOBARS. THUS...EXPECT SHRA/TSRA TO BREAK OUT ACROSS NRN MN INTO ONTARIO BY LATE AFTN. IN THE MEANTIME...IT WILL BE A TRANQUIL DAY ACROSS FCST AREA WITH LAKE BREEZES DOMINATING AS HIGH PRES PASSES ACROSS THE UPPER LAKES THOUGH LAKE BREEZE WILL BE SLOW TO DEVELOP ALONG LAKE MICHIGAN WITH RIDGE NOT ARRIVING THERE UNTIL AFTN. PLENTY OF SUNSHINE EARLY WILL GIVE WAY TO SOME INCREASE IN CLOUDS DURING THE AFTN... ESPECIALLY W. THE GENERALLY WARMER GFS MOS GUIDANCE LOOKS ACCEPTABLE FOR HIGHS. SHRA/TSRA THAT ARE EXPECTED TO DEVELOP TO THE NW THIS AFTN WILL SLIDE ESE INTO UPPER MI TONIGHT AS STRONGER WAA PATTERN SHIFTS OVER UPPER MI. 1-6KM SHEAR OF 40 TO 60KT PER NAM WILL SUPPORT STORM ORGANIZATION AND POTENTIAL SVR STORMS WHILE 30KT FROM GFS IS LESS SUPPORTIVE. THERE IS A BIG DIFFERENCE IN CAPE BTWN NAM/GFS. WITH EXPECTATION OF ELEVATED CONVECTION...NAM MUCAPE IN THE 925-850MB LAYER IS UPWARDS OF 1000J/KG WHILE GFS ONLY HAS ABOUT 300J/KG. OBVIOUSLY...THE NAM OUTPUT IS MUCH MORE SUPPORTIVE OF POTENTIAL SVR STORMS GIVEN SHEAR. THE GFS WOULD SUGGEST NO THREAT OF SVR STORMS. AT THIS POINT...IT IS DIFFICULT TO DETERMINE WHICH MODEL MAY HAVE THE BETTER HANDLE ON COLUMN TEMP/MOISTURE CHARACTERISTICS...BUT WILL LEAN TOWARD THE GFS AS IT APPEARS NAM MAY BE OVERLY AGGRESSIVE IN MOISTENING THE LOW-LEVELS. SINCE BEST COMBINATION OF STRONGEST ISENTROPIC ASCENT/LOWEST CONDENSATION PRES DEFICITS PASSES ACROSS LAKE SUPERIOR AND BRUSHES NRN/ERN FCST AREA...WILL TREND POPS FROM 50 ACROSS ISLE ROYALE/NRN AND ERN LAKE SUPERIOR TO 40 KEWEENAW/ALGER/LUCE TO 20 SW. SOME CONVECTION MAY PERSIST THRU THE DAY SAT ACROSS FAR NRN PORTIONS OF LAKE SUPERIOR AS STRONGER ISENTROPIC LINGERS THERE THRU THE DAY. OTHERWISE...AFTER ANY EARLY MORNING PCPN N AND E...APPEARS DRYING WILL BE SUFFICIENT TO PRECLUDE ANY ADDITIONAL CONVECTION FROM DEVELOPING (K INDEX VALUES FALL BLO 10 IN THE AFTN). MLCIN IS ALSO QUITE HIGH DURING THE AFTN WITH VALUES GENERALLY ABOVE 80J/KG. SHOULD BECOME BREEZY WITH 950MB WINDS OF 20-25KT. WARMER GFS MOS HIGHS LOOK REASONABLE AND ARE INLINE WITH GOING FCST FOR SAT. SAT NIGHT/SUN...ATTENTION TURNS TO THE MIDLEVEL LOW CURRENTLY OVER BRITISH COLUMBIA. UKMET/CANADIAN/GFS/NAM ARE IN DECENT AGREEMENT ON TIMING THIS SYSTEM INTO ONTARIO BY 12Z SUN AND THEN PASSING JUST N OF LAKE SUPERIOR SUN AFTN. NAM IS AN OUTLIER HOWEVER IN SHOWING MORE SUBSTANTIAL HEIGHT FALLS FARTHER S OVER UPPER MI...AND IT WILL NOT BE USED. ASSOCIATED COLD FRONT SHOULD REACH WRN UPPER MI EARLY SUN MORNING AND EXIT THE E LATE AFTN. WITH TIMING DURING THE TYPICAL DIURNAL MIN FOR CONVECTIVE ACTIVITY ALONG A COLD FRONT...PCPN SHOULD BE SOMEWHAT LIMITED AS FRONT PASSES ACROSS THE AREA. THIS IS ESPECIALLY TRUE SINCE THE STRONG DYNAMICS WITH THE MIDLEVEL SYSTEM WILL PASS N OF UPPER MI. IN ADDITION...MLCAPE WHICH IS UPWARDS OF 2000-3000J/KG IN MN SAT EVENING DROPS SUBSTANTIALLY TO UNDER 400J/KG BY THE TIME INSTABILITY AXIS REACHES UPPER MI BY 12Z SUN. SO...WILL CONTINUE TO KEEP POPS IN THE CHC RANGE...SPREADING FROM W TO E SAT NIGHT/SUN MORNING. DEPENDING ON EXACT TIMING OF FRONT...THERE MAY BE AN OPPORTUNITY TO BUILD INSTABILITY SUN AFTN BEFORE FRONT CLEARS THE SE COUNTIES. WITH SW WINDS STAYING UP SAT NIGHT AHEAD OF FRONT AND 850MB THERMAL RIDGE ARRIVING...WILL KEEP MINS AOA WARMEST MOS GUIDANCE...ESPECIALLY IN AREAS THAT SEE DOWNSLOPING WITH A SW WIND (LOWS SHOULD BE AROUND 70 IN THOSE AREAS). HIGH PRES SETTLES IN BEHIND THIS SYSTEM FOR MON TO PROVIDE A PLEASANT EARLY AUG DAY. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE && $$ ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 337 AM CDT FRI AUG 4 2006 .DISCUSSION... SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT PRIMARY FCST CHALLENGE IS T-STORM CHANCES AND POTENTIAL FOR SVR CONVECTION CENTERED DURING LATE SAT AFTERNOON INTO SAT NIGHT PD. EVENING H5 ANALYSIS REVEALED WEAK SHORT WAVE IN WY WHICH GOES WV LOOP HAS TRACKED ACROSS SD THIS MRNG. CONVECTION HAS PERSISTED AHEAD OF THIS...ALONG SHOWALTER AND K-INDEX TIGHT STABILITY GRDT ASSOCIATED WITH LEADING EDGE OF MID LVL WAA ON THE 310K SFC. HAVE LOW POPS IN THRU MRNG WITH THIS GIVEN RUC AND NCEP WRF PROJECTIONS OF THESE FIELDS. TEMPS YESTERDAY GENERALLY HELD BETWEEN 3 TO 7 DEGREES COOLER OVER MOIST GROUND OR SRN TO ERN CWA. EXPECT LESS OF A DIFFERENCE TDA...WITH 85F TO 90F GENERALLY ACROSS CWA. WITH LO LVL RIDGE POSITIONED EAST OF CWA...WARM CONVEYOR BELT WILL RIDE INTO UPPER MISS VALLEY TNGT ON 45KT LO LVL JET PROGGED OVER THE ERN DAKOTAS. THIS WILL LEAN INTO FA AFTER MIDNIGHT. HAVE FOLLOWED THE LESS AGGRESSIVE GFS...WHICH BASED ON PW CHANGE AND UPGLIDE ON THETA SFCS...INDICATES BEST MOISTENING WILL BE MAINLY NEAR DAWN INTO THE MID MORNING SAT HOURS. TEMPS WILL BE SEVERAL DEGREES WARMER TNGT WITH TIGHTENING GRDT AND SRLY FLOW. H8 THETA-E ADVECTION MAX PUSHES EAST ACROSS FA LATE SAT MRNG AND INTO EARLY AFT PLACING FA IN WARM SECTOR. SHOULD BE A BREAK FOR SW HALF OF FA DURING THIS TIME. OVER THE PAST 48 HOURS...THE NAM AND GFS HAVE COME INTO VERY STRONG AGREEMENT ON CONVECTIVE INITIATION TIMING AND LOCATION...THOUGH AFTER THAT POINT THE NAM_WRF EXHIBITS SOME RADICAL HASTE IN MOVING STORMS EWRD. SO IN ENVIRONMENTAL ASSESSMENT FOR SVR POTENTIAL HAVE USED BOTH MODELS...BUT GUIDE WITH THE GFS INTO SAT NIGHT AND SUN. STRONG COLD FRONT FROM PARENT LOW NEAR INTL BORDER WILL MV EAST OUT OF THE UPPER PLAINS DURING SAT AFTN AND STEER BDL TDS INTO THE LOWER 70S BY 00Z. CAP PROGGED TO COMPLETELY ERODE BY LATE AFT ALONG FRONT POSITIONED NEAR WRN MN. BRING IN HIGHER POPS AFTER THAT POINT. 100KT H3 NWRLY JET AND 50KT H7 WRLY JET OVER NW MN LEADS TO IMPRESSIVE DEEP LAYER SHEAR OVR MOST OF THE STATE. SO EXPECT ORGANIZED CONVECTION TO FORM WHICH BOTH MODELS HONE IN ON NRN CWA. HAVE SVR MENTION IN THIS AREA GIVEN SHEAR AND IMPRESSIVE LAPSE RATES ALL THE WAY UP TO THE -20C LVL. BEST UPPER THICKNESS DIFLUENCE WITH THESE JETS AND POTENTIAL FOR LOW LVL BACKING FLOW REMAINS OVER NRN MN AT THIS POINT...KEEPING SUPERCELL POTENTIAL UP THERE. WITH SLOWER GFS SOLUTION SHIFT LKLY POPS FROM WEST TO EAST OVER A GOOD PORTION OF CWA ON SAT NIGHT...KEEPING ONLY LOW POPS FOR SRN AND ERN AREAS ON A COOLER SUN. SHOULD BE SOME MID 50S WITH DRIER AIR MASS AND SLACKENING GRDT ON SUN NIGHT. LONGER TERM...MONDAY THROUGH FRIDAY PLENTY OF UNCERTAINTY REMAINS IN FORECAST DURING THE PERIOD. ECMWF CONTINUES THE TREND OF HANGING UP THE BOUNDARY THAT MOVES THROUGH THE AREA ON SUNDAY...WITH POSSIBLE CONVECTION INTO SOUTHERN CWA. GFS IS CLOSE BUT A LITTLE FARTHER SOUTH...AND UKMET EVEN FARTHER SOUTH. WILL KEEP THE DRY FORECAST INTO TUESDAY...BUT THERE ARE HINTS THAT THE WARM ADVECTION AND BOUNDARY WILL BECOME ACTIVE TUESDAY NIGHT AND WEDNESDAY TIME FRAME. LONGER RANGE ENSEMBLE POP PATTERN FROM YESTERDAY SHOWS A SUB TROPICAL CONNECTION DEVELOPING AGAIN. WITH SOME CONSIDERATION OF ECMWF...WILL GO AHEAD AND ADD SOME SMALL POPS DURING THIS PERIOD. THIS SIGNAL ROLLS OVER OFF TO OUR EAST AND SOUTH TOWARD THURSDAY AND FRIDAY. TEMPS REMAINING NEAR OR ABOVE NORMAL WITH HIGH 500 MB HEIGHTS. THURSDAY COULD BE THE WARMEST DAY..HAVE NOT GONE MUCH PAST THE LOWER 90S...BUT THIS COULD BE LOOKED AT LATER. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MTF/JPR mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 400 AM CDT FRI AUG 4 2006 .DISCUSSION... THE 00Z SHORT-TERM MODELS (TIL SUNDAY NIGHT)...ARE IN REASONABLE AGREEMENT ON H500 MASS FIELDS...WITH H500 RIDGE TO DOMINATE THRU THE PERIOD...WITH RIDGE EVEN REINFORCING ITSELF AS 594DM DEVELOPS OVER THE MID MS VALLEY BY SUNDAY. DIFFERENCES ARISE IN THE SLOPE OF THE 594DM CONTOUR...WITH NAM SHOWING MORE OF A SEWD FLOW OVER OUR AREA VERSUS A MORE ESEWD FLOW WITH THE GFS AND OTHER MODELS. THIS COMES INTO PLAY WITH WHAT IS SEEN AT THE SFC...WITH HI PRES IN CONTROL THRU TONIGHT WITH RIDGE FADING ON SATURDAY. CDFNT IS EXPECTED TO APPROACH THE AREA LATE SATURDAY NIGHT AND SUNDAY... WITH NAM NOTABLY MORE PROGRESSIVE WITH SEWD PENETRATION OF CDFNT THRU THE FA ON SUNDAY THAN OTHER MODELS...ESPECIALLY THE GFS... WHICH KEEPS IT NO FURTHER S THAN THE NRN FA BY SUNDAY NIGHT. THIS IS ALSO SUPPORTED BY THE ECMWF AND UKMET AND TO A LESSER EXTENT BY THE NOGAPS AND CMC GEM. SO WITH NAM BEING THE OUTLIER...WILL FAVOR A SLOWER SOLUTION ON CDFNT FOR THE TIME BEING. FOR TODAY...SCT SHRA/TSRA HAVE DEVELOPED IN THE PAST HOUR IN THE FAR SRN FA...AND APPEARS TO BE THE WORK OF H850 CDFNT. EXPECT THIS TO EXIT THE FA AROUND 12Z...LEAVING THE FA DRY FOR THE REST OF THIS PERIOD. H850 TEMPS EXPECTED TO BE AROUND 17-18C...AND WITH ELY SFC WINDS AND DECENT SUNSHINE...THIS WILL RESULT IN ANOTHER SEASONABLE DAY WITH HIGHS IN THE UPPER 80S...WHICH FAVORS A MAV/MET MOS BLEND. FOR TONIGHT...CLEAR/MOSTLY CLEAR SKIES EXPECTED WITH SFC RIDGE TO CONTINUE TO DOMINATE THE AREA. LEANED TOWARDS THE COOLER END OF MOS FOR MIN TEMPS. FOR SATURDAY...MOISTURE TO BEGIN STREAMING N AROUND THE WRN EDGE OF THE FA THIS PERIOD AS LO LEVEL RIDGE FADES. INSTABILITY STILL RATHER MEAGER ALONG WITH THE NEAR COMPLETE ABSENCE OF ANY FORCING... SO THIS PERIOD EXPECTED TO BE DRY DURING THE DAYTIME. HEADING INTO SATURDAY NIGHT...THE NAM SHOWS A MUCH MORE SLY DEVELOPMENT OF EXPECTED MCS OVER THE UPPER MS VALLEY...AND ONE THAT WILL CLIP THE NRN FA LATE. THE MORE PREFERRED GFS SOLUTION KEEPS THINGS TO THE N. HAVE PRESERVED SLIGHT CHANCE POPS FOR THE NRN FA FOR NOW GIVEN UNCERTAINTY OF EVENTUAL TRACK OF THIS MCS. H850 TEMPS ABOUT 1C WARMER THAN TODAY SHOULD RESULT IN MAX TEMPS ABOUT 2-3F HIGHER... ALSO FACTORING IN MORE SELY SFC WINDS...WHICH FAVORS MAV/MET MOS BLEND AGAIN. FOR SUNDAY...FORECAST HERE REVOLVES HEAVILY ON SLOWER SWD PROPAGATING GFS AMONGST OTHER MODELS. APPEARS DECENT MOISTURE/INSTABILITY AXIS WILL SETUP OVER THE NRN FA THIS PERIOD...BUT NOT MUCH ELSE GOING FOR IT OTHER THAN SURFACE CDFNT...AND THAT WILL HAVE TO ALSO CONTEND WITH 12C H700 TEMPS OVERHEAD. MAINTAINED SMALL POPS FOR THIS PERIOD IN AREAS EXPECTED TO BE NEAREST THE FRONT...IN THE NRN HALF OF THE FA. OTHERWISE...HEAT AND HUMIDITY MAKES ITS EXPECTED RETURN TO THE AREA...ALTHOUGH NOT EXPECTED TO HAVE THE SAME PUNCH AS IT DID WITH THIS PAST HEAT WAVE...AT LEAST NOT RIGHT AWAY. WITH SFC DEWPOINTS IN THE LOWER 70S EXPECTED NEAR THE FRONT IN THE N...AND COMBINED WITH MAX TEMPS IN THE MID 90S...THIS WILL PUSH HEAT INDICES CLOSE TO 105F IN SPOTS...NOTABLY ALONG THE I-70 CORRIDOR IN MO. DUE TO UNCERTAINTY IN MODELS AND PCPN CHANCES...AS WELL AS STILL HAVE SOME TIME TO WATCH THIS...WILL FOREGO ANY HEAT HEADLINES AT THIS TIME...BUT BEARS WATCHING. FAVORED THE WARMER MET MOS FOR MAX TEMPS. TES && .AVIATION... FOR THE 06Z TAFS...WILL GO WITH A DRY FCST TGT AT ALL THE TAF SITES AS SCT SHRA/TSRA ARE ALNG CDFNT WHICH HAS PUSHED SE OF STL ATTM. SHOULD HAVE A CLRG SKY TGT AS MID-HI LVL CLOUDINESS OVR CNTRL MO ADVCTS SWD AS DEPICTED BY LATEST RUC RH FCST FOR TGT. SFC RDG EXTDG FM WRN KS NE THRU MN WL BLD SEWD THRU MO IL BHND CDFNT. LGT NLY SFC WNDS OVR THE CWA TGT SHOULD BCM E-NELY ON FRI. MOS GUIDANCE HINTING AT SOME FOG AT THE TAF SITES ARND 12Z FRI... ESPECIALLY AT UIN. WILL PROBABLY MENTION A BRIEF PERIOD OF LGT FOG WITH A CLRG SKY AND LGT WND...ALTHOUGH LWR SFC DWPTS WILL BE FILTERING SEWD THRU THE CWA LT TGT WITH CURRENT TEMP AND DEW POINT SPREADS STILL PRETTY BIG AT 04Z. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 356 AM CDT FRI AUG 4 2006 .DISCUSSION...PAST EVENING UPPER AIR DATA IN COMBINATION WITH RECENT WATER VAPOR IMAGERY REVEALS AN UPPER LEVEL DOME OF HIGH PRESSURE ENTRENCHED ACROSS THE SOUTHERN PLAINS TO LOWER MS RIVER VALLEY REGION. THE LOCATION OF THIS HIGH IS ALLOWING A DEEP MONSOONAL TAP OF MOISTURE TO STREAM NORTH INTO THE SOUTHERN/CENTRAL ROCKIES AND THEN FINALLY ACROSS THE CENTRAL PLAINS. WITHIN THIS BELT OF MONSOONAL MOISTURE SEVERAL SMALL WAVES CAN BE SEEN FROM WEST TEXAS INTO WESTERN KANSAS. SURFACE ANALYSIS SHOWS A NEARLY STALLED OUT FRONT STRETCHING ALONG THE RED RIVER VALLEY REGION OF THE SOUTHERN PLAINS WHILE A DEEPENING AREA OF LOW PRESSURE IS SEEN OVER THE NORTHERN HIGH PLAINS. THIS SETUP IS BEGINNING TO SLOWLY PULL THE DEEPER LOW LEVEL MOISTURE BACK NORTH INTO THE CENTRAL PLAINS THIS MORNING WITH A BELT OF THETA E ADVECTION AT 850MB SHOWN IN THE RUC HELPING TO PRODUCE THE CONVECTION SEEN OVER SOUTHWEST KANSAS. LITTLE IS EXPECTED TO CHANGE WITH THE UPPER PATTERN THROUGH TONIGHT AS THE UPPER HIGH WILL CONTINUE TO SIT OVER THE SOUTHERN PLAINS WHILE A PROGRESSIVE NORTHERN STREAM DIPS AS FAR SOUTH AS NEBRASKA. THIS WILL ALLOW PRESSURE FALLS TO CONTINUE ACROSS THE NORTHERN PLAINS THROUGH TODAY WITH MOISTURE ALSO CONTINUING ITS GRADUALLY MARCH BACK NORTH. THE MAIN QUESTION FOR CENTRAL NEBRASKA INTO NORTH CENTRAL KANSAS FOR TODAY THEN INVOLVES WHETHER THE BELT OF THETA E ADVECTION AT 850MB RESULTING FROM THIS MOISTURE RETURN WILL BE ENOUGH TO TRIGGER ANY THUNDERSTORMS. GIVEN THE TRENDS ONGOING OVER SOUTHWEST KANSAS IT LOOKS LIKE THE ANSWER IS YES. BASED ON THIS EXPECT SOME MORNING SHOWERS AND THUNDERSTORMS TO BE POSSIBLE FOR AREAS MAINLY WEST OF A LEXINGTON TO OSBORNE LINE. ADDITIONAL THUNDERSTORMS THEN LOOK POSSIBLE THIS AFTERNOON INTO TONIGHT AS THIS BELT OF THETA E ADVECTION LIFTS NORTHEAST ACROSS THE REGION. TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY WITH HIGHS VARYING FROM THE MID 80S TO LOWER 90S. SATURDAY IS SHAPING UP TO BE A RATHER INTERESTING WEATHER DAY ACROSS THE REGION AS A STRONG NORTHERN STREAM WAVE RIDING ALONG THE US...CANADIAN BORDER HELPS TO PUSH A DECENT COLD FRONT INTO THE REGION. AHEAD OF THIS BOUNDARY PRE-FRONTAL WARMING WILL PRODUCE A VERY WARM DAY WITH HIGHS EXPECTED TO BE IN THE MID 90S TO AROUND 100 ACROSS AREA. THE OTHER ISSUE INVOLVES THUNDERSTORM CHANCES ALONG THE FRONT. THE ATMOSPHERE SHOULD BE FAIRLY CAPPED INITIALLY GIVEN FAIRLY WARM MID LEVEL TEMPERATURES...BUT FULLY EXPECT CONVECTION TO DEVELOP ALONG THE FRONT BY LATE AFTERNOON. BEST CHANCE SHOULD INITIALLY BE NORTH OF THE PLATTE RIVER DURING THE AFTERNOON BUT WILL THEN SPREAD SOUTH DURING THE EVENING AND OVERNIGHT HOURS. THE MODELS ARE NOT QUITE SURE YET HOW TO HANDLE THE PROGRESSION OF THIS FRONT INTO SUNDAY AS THE NAM-WRF IS ATTEMPTING TO PUSH THE BOUNDARY INTO SOUTHERN KANSAS WHILE THE GFS KEEPS IT ACROSS SOUTHERN NEBRASKA. CONFIDENCE IN EITHER SOLUTION IS FAIRLY LOW AT THIS POINT GIVEN OTHER MODELS SHOWING DIFFERENCES AS WELL. WILL AIM IN THE MIDDLE FOR NOW AND KEEP THE BOUNDARY SOMEWHERE ACROSS NORTHERN KANSAS. GIVEN THIS SETUP...WILL KEEP TEMPERATURES IN THE UPPER 90S ACROSS NORTH CENTRAL KANSAS BUT LOWER HIGHS INTO THE UPPER 80S NEAR ORD. IT APPEARS THIS PATTERN SHOULD FAVOR CONVECTION DEVELOPING OVER THE HIGH PLAINS AND THEN SLIDING EAST NORTH OF THE FRONT DURING THE EVENING AND OVERNIGHT HOURS. BASED ON THIS...WILL KEEP PRECIP CHANCES FOR AREAS NORTH OF THE KANSAS...NEBRASKA BORDER ESSENTIALLY UNCHANGED THROUGH MONDAY MORNING. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 338 AM CDT FRI AUG 4 2006 .SHORT TERM... THE CHALLENGE TODAY THROUGH IS CONVECTIVE POTENTIAL AND PSBL SVR WEATHER TONIGHT AND ON SAT AFTN/EVE. 07Z SFC MAP SHOWS SFC LOW BTWN GLENDIVE AND GLASGOW MONTANA...VERY NEAR THE CANDIAN MODEL FCST OF 24 HOURS AGO. OBS SHOW SFC WARM FRONT TRYING TO FORM FROM NORTH OF DICKINSON TO NEAR JUST NORTH OF ABERDEEN. RUC AND OTHER MODELS SHOW CURRENT 35-40 KT 850 MB JET OVER WRN AND CNTRL ND...WITH NOSE OF JET AND BEST CONVERGENCE OVER SE SASK/NW ND/SW MANITOBA. CURRENT RADARS SHOW BEST COVERAGE OF STORMS IN THIS AREA. ANOTHER AREA OF ELEVATED STORMS ASSOC WITH A VORT MAX MOVING THRU NORTH CENTRAL AND NORTHEAST SD. THIS ACTIVITY HAS SHOWS TENDENCY TO DEVELOP NORTHEAST WITH TIME AND MAY CLIP FAR SOUTHEASTERN AREAS. YET A FEW MORE ISOLATED SHOWER/TSTMS FORMING AROUND DEVILS LAKE AND IN THE PKD/DTL AREAS IN MINNESOTA. LOW LEVEL JET WILL VEER EAST SLOWLY TODAY...WIT NOSE OF JET ALONG THE CANADIAN BORDER FOR MUCH OF THE DAY. THUS DID INCREASE POPS A BIT UP ACROSS OUR NORTHERN FCST AREA BUT KEPT IN SCATTERED CATEGORY. OTHER ACTIVITY IN THE SE ND INTO WCNTRL ND WILL LIKELY BE JUST MORNING ACTIVITY SO KEPT THIS AREA DRY THIS AFTN. FOCUS FOR ANY DAYTIME HEATING CONVECTION WILL REST WELL WEST OF THE AREA CLOSER TO FRONT AND SFC LOW IN FAR WRN ND/NW SD. KEPT CONTINUITY WITH REGARDS TO HIGH TEMPS WITH LOWER 80S NORTHEAST TO NR 90 FAR SOUTHWESTERN AREAS. NAM SFC TEMPS IN THE FAR SOUTH OF 95-98 LOOK EXTREMELY WARM...APPARENTLY MODEL IS TRYING TO BRING AIR DOWN FROM 850 OR HIGHER AND DRYING OUT THE SFC DEW PTS IN THE PROCESS. THIS DOES NOT APPEAR REASONABLE AT THIS TIME AND DISCOUNTED. KEPT RH VALUES WELL ABOVE RED FLAG ISSUES THIS AFTN. IT WILL BE BREEZY-WINDY AS SOME OF THE 35-40KT 850 MB WINDS TRY TO MIX DOWN AT TIMES TO THE SFC AS SFC GRADIENT TIGHTENS OVER EASTERN NORTH DAKOTA MIDDAY AND AFTN. LIKED 00Z GFS SOLN FOR TONIGHT INTO SATURDAY...AS IT SEEMS BEST IN HITTING THE BEST CHC OF NIGHTTIME CONVECTION ALONG THE CANADIAN BORDER AND INTO NRN MN...LATE EVENING THRU LATE NIGHT HOURS. 850 MB JET IS CLOSER TO 45 KTS TONIGHT AND COVERGENCE IS QUITE STRONG JUST NORTH OF THE BORDER. SOME HAILERS VERY POSSIBLE WITH THIS PROBABLE COMPLEX TO FORM TONIGHT OVER OUR FAR NORTH AND SOUTHEASTERN MANITOBA. SEE SWODY1. FOR THAT MATTER...COULD NOT RULE OUT ISOLD HAILERS WITH ANY STORM TODAY THAT FORMS. FREEZING LEVELS AROUND 13300-13500 FT. LOW PRESSURE WILL MOVE EAST INTO NORTHEAST ND SATURDAY AFTN WITH COLD FRONT NR A HALLOCK-WEST OF GRAND FORKS-VALLEY CITY LINE AT 18Z AND LIKELY NR A ROSEAU-THIEF RIVER FALLS-WAHPETON LINE AT 00Z SUN. SWODY2 HAS AREA ALONG AND EAST OF FRONT IN SLIGHT RISK...PSBL MDT RISK UPGRADE...AND THIS IS REASONABLE CONSIDERING PRETTY STRONG MID LEVEL WINDS LOCATED JUST SOUTH OF THE UPPER LOW WHICH WILL BE MOVING TO NEAR KENORA ONTARIO BY EARLY EVENING. DAYTIME HEATING IS KEY...DID GO WITH TEMPS IN THE UPPER ALONG THE FRONT...WHICH COMBINED WITH MID-UPPER 60S DEW PTS SHOULD GIVE CAPES IN THE 3000-4000 J/KG RANGE ALONG FRONT AT MID AFTN SATURDAY. WOULD EXPECT MAIN CONVECTION TO FIRE ALONG FRONT NR 20- 21Z SOMEWHERE NR THE ROX-CKN-FAR AREAS AND THEN PUSH EAST. DID INCREASE POPS TO 50 PCT IN MUCH OF NW/WCNTRL MN DUE TO INCREASED CONFIDENCE OF PCPN. DID KEEP LOW POPS WEST OF THE VALLEY OVER DVL REGION BUT PCPN CHANCES ARE MUCH LESS HERE AS FRONT COMES THRU BEFORE 18Z. RAPID CLEARING/DRYING TO OCCUR BEHIND THE FRONT SATURDAY EVENING WITH HIGH PRESSURE BUILDING IN TO OUT WEST AND SOUTHWEST SAT NIGHT INTO SUNDAY. NAM TRIES TO WRAPUP SFC LOW AND 500 MB LOW NORTH OF INTERNATIONAL FALLS SAT NIGHT AND EARLY SUNDAY...THUS BRINGING DOWN STRONG WINDS AND SOME 850 MB MOISTURE. GFS IS MORE PROGRESSIVE WITH SYSTEM AND IS DRIER WITH LESS 850 MB WINDS. ATTM GFS IS CLOSE TO CANADIAN MODEL AND IS PREFERRED. SUNDAY WILL BE COOLER BUT NOT AS COOL AS NAM PAINTS IT TO BE. .LONG TERM... MONDAY AND TUESDAY WILL SEE 500 MB RIDGE BUILDING BACK NORTHWEST INTO WYOMING WHILE CENTER REMAINS OVER ARKANSAS. CONSENSU FOR PAST 2 DAYS AMONG MOST MODELS IS FOR SOME UPPER WAVE AND SFC LOW TO AFFECT THE AREA TUES NIGHT INTO WEDNESDAY PERIOD...AND FELT ENOUGH CONFIDENCE TO ADD A 20 POP FOR THUNDER FOR THESE PERIODS. FOR VERY LATE NEXT WEEK GFS WANTS TO DIVE A TROUGH AND A COLD FRONT THRU ON FRIDAY. THIS IS NOT SUPPORTED BY CANADIAN AND ECMWF WHICH KEEPS ZONAL FLOW AND WARMER AIR. ATTM TRENDED TEMPS ABV GFS MOS FOR THU- FRI PERIOD. WILL LET DAYSHIFT REVIEW HPC RECOMMENDATIONS FOR CHANGES. && .AVIATION... VFR CONDITIONS TODAY. PROBLEM THRU TONIGHT IS ISOLD THUNDERSTORM ACTIVITY WHICH WOULD IMPACT AIRPORTS. VERY DIFFICULT TO GET ANY TIMING DOWN AS ACTIVITY AT GFK-BJI-FAR AIRPORTS LIKELY TO BE ISOLATED VERSUS BETTER COVERAGE NORTH ALONG THE CANADIAN BORDER. CLOUDS TO REMAIN IN THE 8000 TO 12000 KT RANGE TODAY AND SCT-BKN IN COVERAGE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ RIDDLE nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAKE CHARLES LA 957 AM CDT FRI AUG 4 2006 .SYNOPSIS...LIMITED TROPICAL MOISTURE CARRIED IN FROM THE EAST FROM AN UPPER LOW OFF THE FLORIDA WEST COAST WILL BRING MINIMAL CHANCES FOR AFTERNOON THUNDERSTORMS TO THE AREA TODAY. DESCENDING AIR ON THE WESTERN FRINGES OF THIS SYSTEM WILL ALLOW FOR COMPRESSIONAL WARMING OF THE LOWER LAYERS OF THE ATMOSPHERE, THUS WARMER THAN NORMAL TEMPERATURES. COMBINED WITH THE HIGH HUMIDITIES, HEAT INDICES BETWEEN 100 AND 105 WILL BE FAIRLY COMMON THIS AFTERNOON. && .UPDATE...OTHER THAN A TWEAK DOWNWARD ON AFTERNOON TEMP AT BPT DUE TO ADDITIONAL LOW LEVEL CLOUDCOVER AS SEEN ON THE RUC H925 RH FIELD, CURRENT FORECAST LOOKS GOOD. WILL ADJUST TEMPS TO LOWER 90S FOR LWR SE TX...NEAR THE COAST. && .MARINE...CHECKED OVER NAM WINDS...THEY LOOK REASONABLE AND MATCH SURROUNDING COASTAL ZONES SO WENT AHEAD AND POPULATED NEW NAM (VS OLD GFS). ADJUSTED WAVE HEIGHTS UP SLIGHTLY. LIGHT SE TO E WINDS. && .PREV DISCUSSION... (ISSUED 533 AM CDT FRI AUG 4 2006) DISCUSSION...WV SATELLITE IMAGERY/UA ANALYSIS SHOWED H5 RIDGE CENTERED OVER THE ARKLATEX REGION...WITH UPPER LOW SPINNING JUST EAST OF THE CENTRAL FL COAST. TS CHRIS...THE LOW LEVEL CENTER AT LEAST...WAS CENTERED NORTH OF HISPANOLA. NOT MUCH CHANGE FROM PREVIOUS FORECAST THINKING...WITH A CHANGE FOR THE WETTER...SO TO SPEAK...ON THE HORIZON. WV CONTINUES TO SHOW DEEPER MOISTURE PLUME SPREADING INTO THE AREA FROM THE EAST...AND THIS IS FURTHER REINFORCED BY KLCH 00Z RAOB...WHICH YIELDED A PWAT OF 1.67 INCHES...WHICH IS .20 INCHES HIGHER THAN 12 HRS AGO. NOT RAPID MOISTENING...BUT MOISTENING NONETHELESS. ISOLATED RW OVER THE CW AGAIN THIS MORNING...SOME OF WHICH IS MANAGING TO CREEP INLAND. EXPECTING A BIT MORE COVERAGE OF AFTERNOON TRW TODAY VS. YESTERDAY WITH LESS OF AN INHIBITING EFFECT BY THE UPPER RIDGE TO THE NORTHWEST. GIVEN HOW PALTRY THE COVERAGE WAS YESTERDAY...THIS STILL ONLY MEANS A SLIGHT CHANCE AT BEST FOR MOST OF THE AREA...WITH A CHANCE OVER FAR SOUTHEAST ZONES WITH THE GFS HINTING AT A WEAK VORT LOBE ROUNDING THE RIDGE. EVEN THIS MAY BE SUSPECT AS THE GFS IS RACKED WITH CONVECTIVE FEEDBACK THROUGH ABOUT 60 HRS. HAVING SAID THAT...I STILL PREFER ITS OVERALL HANDLING OF THE UPPER TROF MOVING IN FROM THE EAST V.S THE NAM...WHICH HAS BECOME USELESS AT TIMES WITH THE ABSURD NUMBER OF TROPICAL CYCLONES IT HAS GENERATED IN THE GULF THIS YEAR. ALSO WENT WITH THE GFS IN THE EXTENDED...WHICH CONTINUES TO BE SUPPORTED QUITE WELL BY THE ECMWF IN SHOWING THE DEVELOPMENT OF A MONSTROUS RIDGE OVER THE SOUTHERN PLAINS BY EARLY TO MID NEXT WEEK. DO NOT THINK THIS WILL TOTALLY QUASH RAIN CHANCES...AS IT LOOKS TO BE CENTERED FAR ENOUGH NORTH THAT WE SHOULD STILL SEE THE OCCASIONAL INVERTED TROF...AND WITH THE SFC RIDGE STILL CENTERED TO THE EAST...AN AFTERNOON SEA BREEZE. FOR POPS SATURDAY AND BEYOND...HAVE LEFT THE INHERITED GRIDS AS IS...WHICH CARRY A LOW TO MID RANGE POP OVER THE WEEKEND...AND RETURN TO CLIMO VALUES THROUGH THE REST OF THE EXTENDED. HAVE TAKEN NOTE OF THE INCREASE IN POPS SHOWN ON THE OPERATIONAL GFS GUIDANCE FOR SUNDAY AND MONDAY. AS OF THE 03/00 ENSEMBLE...IT WAS STILL ON THE HIGH SIDE...BUT AS I LOOK AT THE 04/00 ENSEMBLE NUMBERS WHICH WERE NOT AVAILABLE AS I PRODUCED THE GRIDS...THE LATEST MEX NUMBERS ARE QUITE CLOSE TO THE MEAN. AN INCREASE IN POPS MAY BE WARRANTED IF THIS CONTINUES TO HOLD. FOR TEMPERATURES...IN THE NEAR TERM...HAVE CONTINUED TO UNDERCUT THE WARM-BIASED MAV FOR AFTERNOON HIGHS...THOUGH ITS LOW TEMPERATURES LOOK REASONABLE. IN THE EXTENDED...CONTINUED TO LEAN ON THE ENSEMBLE GUIDANCE. AVIATION...TEMPO MVFR KAEX-KBPT-KLCH...BUT OTHERWISE VFR WILL PREVAIL TODAY. MARINE...LIGHT ONSHORE FLOW AND RELATIVELY LOW SEAS WILL PERSIST THROUGH THE WEEKEND. MARINE INTERESTS SHOULD CONTINUE TO MONITOR THE PROGRESS OF TROPICAL STORM CHRIS...WHICH IS FORECAST TO EMERGE INTO THE SOUTHEAST GULF OF MEXICO ON SUNDAY. && .UPDATED POINT TEMPS/POPS... KLCH 94 75 93 76 / 20 0 40 30 KBPT 93 75 93 76 / 20 0 40 30 KAEX 97 74 95 74 / 20 0 30 30 KLFT 95 76 94 76 / 30 10 40 40 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...NONE. && $$ 13/11 la AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE HASTINGS NE 535 AM CDT FRI AUG 4 2006 .DISCUSSION...QUICK UPDATE TO THE FORECAST AND GRIDS TO REFLECT MORE CLOUD COVER FOR AREAS SOUTHWEST OF A HOLDREGE TO BELOIT LINE THIS MORNING. NO OTHER CHANGES MADE AT THIS TIME. && .PREV DISCUSSION... (ISSUED 356 AM CDT FRI AUG 4 2006) DISCUSSION...PAST EVENING UPPER AIR DATA IN COMBINATION WITH RECENT WATER VAPOR IMAGERY REVEALS AN UPPER LEVEL DOME OF HIGH PRESSURE ENTRENCHED ACROSS THE SOUTHERN PLAINS TO LOWER MS RIVER VALLEY REGION. THE LOCATION OF THIS HIGH IS ALLOWING A DEEP MONSOONAL TAP OF MOISTURE TO STREAM NORTH INTO THE SOUTHERN/CENTRAL ROCKIES AND THEN FINALLY ACROSS THE CENTRAL PLAINS. WITHIN THIS BELT OF MONSOONAL MOISTURE SEVERAL SMALL WAVES CAN BE SEEN FROM WEST TEXAS INTO WESTERN KANSAS. SURFACE ANALYSIS SHOWS A NEARLY STALLED OUT FRONT STRETCHING ALONG THE RED RIVER VALLEY REGION OF THE SOUTHERN PLAINS WHILE A DEEPENING AREA OF LOW PRESSURE IS SEEN OVER THE NORTHERN HIGH PLAINS. THIS SETUP IS BEGINNING TO SLOWLY PULL THE DEEPER LOW LEVEL MOISTURE BACK NORTH INTO THE CENTRAL PLAINS THIS MORNING WITH A BELT OF THETA E ADVECTION AT 850MB SHOWN IN THE RUC HELPING TO PRODUCE THE CONVECTION SEEN OVER SOUTHWEST KANSAS. LITTLE IS EXPECTED TO CHANGE WITH THE UPPER PATTERN THROUGH TONIGHT AS THE UPPER HIGH WILL CONTINUE TO SIT OVER THE SOUTHERN PLAINS WHILE A PROGRESSIVE NORTHERN STREAM DIPS AS FAR SOUTH AS NEBRASKA. THIS WILL ALLOW PRESSURE FALLS TO CONTINUE ACROSS THE NORTHERN PLAINS THROUGH TODAY WITH MOISTURE ALSO CONTINUING ITS GRADUALLY MARCH BACK NORTH. THE MAIN QUESTION FOR CENTRAL NEBRASKA INTO NORTH CENTRAL KANSAS FOR TODAY THEN INVOLVES WHETHER THE BELT OF THETA E ADVECTION AT 850MB RESULTING FROM THIS MOISTURE RETURN WILL BE ENOUGH TO TRIGGER ANY THUNDERSTORMS. GIVEN THE TRENDS ONGOING OVER SOUTHWEST KANSAS IT LOOKS LIKE THE ANSWER IS YES. BASED ON THIS EXPECT SOME MORNING SHOWERS AND THUNDERSTORMS TO BE POSSIBLE FOR AREAS MAINLY WEST OF A LEXINGTON TO OSBORNE LINE. ADDITIONAL THUNDERSTORMS THEN LOOK POSSIBLE THIS AFTERNOON INTO TONIGHT AS THIS BELT OF THETA E ADVECTION LIFTS NORTHEAST ACROSS THE REGION. TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY WITH HIGHS VARYING FROM THE MID 80S TO LOWER 90S. SATURDAY IS SHAPING UP TO BE A RATHER INTERESTING WEATHER DAY ACROSS THE REGION AS A STRONG NORTHERN STREAM WAVE RIDING ALONG THE US...CANADIAN BORDER HELPS TO PUSH A DECENT COLD FRONT INTO THE REGION. AHEAD OF THIS BOUNDARY PRE-FRONTAL WARMING WILL PRODUCE A VERY WARM DAY WITH HIGHS EXPECTED TO BE IN THE MID 90S TO AROUND 100 ACROSS AREA. THE OTHER ISSUE INVOLVES THUNDERSTORM CHANCES ALONG THE FRONT. THE ATMOSPHERE SHOULD BE FAIRLY CAPPED INITIALLY GIVEN FAIRLY WARM MID LEVEL TEMPERATURES...BUT FULLY EXPECT CONVECTION TO DEVELOP ALONG THE FRONT BY LATE AFTERNOON. BEST CHANCE SHOULD INITIALLY BE NORTH OF THE PLATTE RIVER DURING THE AFTERNOON BUT WILL THEN SPREAD SOUTH DURING THE EVENING AND OVERNIGHT HOURS. THE MODELS ARE NOT QUITE SURE YET HOW TO HANDLE THE PROGRESSION OF THIS FRONT INTO SUNDAY AS THE NAM-WRF IS ATTEMPTING TO PUSH THE BOUNDARY INTO SOUTHERN KANSAS WHILE THE GFS KEEPS IT ACROSS SOUTHERN NEBRASKA. CONFIDENCE IN EITHER SOLUTION IS FAIRLY LOW AT THIS POINT GIVEN OTHER MODELS SHOWING DIFFERENCES AS WELL. WILL AIM IN THE MIDDLE FOR NOW AND KEEP THE BOUNDARY SOMEWHERE ACROSS NORTHERN KANSAS. GIVEN THIS SETUP...WILL KEEP TEMPERATURES IN THE UPPER 90S ACROSS NORTH CENTRAL KANSAS BUT LOWER HIGHS INTO THE UPPER 80S NEAR ORD. IT APPEARS THIS PATTERN SHOULD FAVOR CONVECTION DEVELOPING OVER THE HIGH PLAINS AND THEN SLIDING EAST NORTH OF THE FRONT DURING THE EVENING AND OVERNIGHT HOURS. BASED ON THIS...WILL KEEP PRECIP CHANCES FOR AREAS NORTH OF THE KANSAS...NEBRASKA BORDER ESSENTIALLY UNCHANGED THROUGH MONDAY MORNING. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAND FORKS ND 1059 AM CDT FRI AUG 4 2006 .UPDATE...STILL NOT AN EASY FORECAST TODAY EVEN WITH MANY CHALLENGES INCLUDING CONVECTIVE CHANCES AND FIRE WX CONCERNS. AS OF 15Z...WARM FRONT HAS SET UP FROM W-E ACROSS THE CENTRAL FA. STRONG 850MB WARM AIR ADVECTION ACROSS THE INTERNATIONAL BORDER COMBINED WITH STEEP LAPSE RATES AND 50-60KT OF DEEP LAYERED SHEAR HAVE COMBINED FOR A FEW SEVERE STORMS. AS 850MB JET SLOWLY SHIFTS E THROUGH THE DAY...EXPECT THIS AREA OF STORMS TO SHIFT E ALSO. WILL INCREASE POPS JUST ALONG CANADIAN BORDER FOR TODAY A BIT. WITH DEEP LAYERED SHEAR SO STRONG WOULD EXPECT A FEW STORMS TO BE AT LEAST NEAR SEVERE ALL DAY. SECONDARY STRONGER AREA OF 850MB WARM AIR ADVECTION NOW ACROSS SE ND WILL SLOWLY LIFT NE THROUGH THE DAY. ISOLD THUNDER NOW OCCURRING SHOULD LIFT NE ALONG WITH THIS FORCING. MODELS ARE HINTING AT A POCKET OF DRIER 850MB AIR WHICH IS TO LIFT INTO THE S FA TODAY AND END THE ISOLD THUNDER BY MID-AFTERNOON. CURRENT POPS LOOK GOOD FOR THIS...BUT WILL EXTEND THE ISOLD THREAT INTO THE EARLY AFTERNOON TO ACCOUNT FOR CURRENT ACTIVITY. 12Z RUC/GFS LIFT WARM FRONT N OF BORDER BY 00Z SAT...WHILE 12Z NAM KEEPS WARM FRONT STATIONARY. WILL NEED TO MONITOR THE POSITION OF THIS FRONT FOR AFTERNOON/EVENING SEVERE THREAT. WILL ALSO NEED TO MONITOR SFC DEWPOINTS ACROSS SE ND. WITH POCKET OF DRIER 850MB AIR MOVING INTO THIS REGION EXPECT SOME DRYING AT THE SFC AS THIS DRIER AIR MIXES DOWN. NOT SURE TO WHAT DEGREE THIS WILL OCCUR...BUT IF DEWPOINTS REACH NEAR 45F WITH TEMPS NEAR 90F (RH 20%) AND WITH WINDS NEAR 25KTS FIRE WX CONDITIONS BECOME CRITICAL. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 915 AM CDT FRI AUG 4 2006 .DISCUSSION...THIS MORNINGS BRO SOUNDING SHOWS A FAIRLY TYPICAL SUMMERTIME AIRMASS IN PLACE OVER THE REGION WITH A PWAT OF AROUND 2 INCHES AND A CAPE OF 5386 J/KG. DIURNAL HEATING AND LOCALIZED SEA BREEZE EFFECTS SHOULD HELP FIRE OFF SOME MORE CONV LATER TODAY AND WILL LEAVE IN THE MENTION OF CHC POPS IN THE FIRST PERIOD FOR THE ENTIRE BRO CWA. THE LATEST RUC GUIDANCE KEEPS THE 500 MB LOW NOW POSITIONED OVER THE BIG BEND AREA MOVING OUT TO THE NORTH AND WEST AWAY FROM THE CWA WHICH SHOULD LIMIT ANY SIGNIFICANT UPPER LEVEL SUPPORT ACROSS THE REGION TODAY. MAV AND MET TEMP GUIDANCE IS IN REASONABLE AGREEMENT TODAY AND WILL STICK PRETTY CLOSE TO THIS. OVERALL ZFP WORDING LOOKS OK WITH NO MAJOR CHANGES NEEDED. && .MARINE...BUOY020 REPORTED E WINDS AT 5 TO 10 KTS AND SEAS AT 3 FEET. LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS WILL PREVAIL THROUGH THE WEEKEND. AN UPPER LEVEL LOW...CURRENTLY OVER FLORIDA...WILL MOVE INTO THE WESTERN GULF BY SUN INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS OVER THE LOWER TEXAS COASTAL WATERS EARLY NEXT WEEK. WILL CONTINUE TO MONITOR TROPICAL DEPRESSION CHRIS LOCATED NEAR HISPANIOLA IS FORECAST TO MOVE TOWARDS THE WESTERN GULF BY TUE. IF THIS DOES OCCUR AND CHRIS REMAINS A TROPICAL CYCLONE...WINDS AND SEAS WILL INCREASE ACROSS OVER THE REGION THROUGH THE MIDDLE OF NEXT WEEK. && .AVIATION...VFR CONDITIONS WILL PREVAIL TODAY WITH TEMPO MVFR TO IFR CONDITIONS AS ISOLD TSRA/SHRA DEVELOP AND MOVE INLAND ALONG THE SEA BREEZE FRONT. PATCHY FG WILL PRODUCE MVFR TO IFR VIS OVER NRN ZONES AROUND SUNRISE SAT. && .BRO WATCHES/WARNINGS/ADVISORIES...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO SYNOPTIC/GRIDS...60 MARINE/AVIATION...55 MESO...MARTINEZ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1050 AM EDT FRI AUG 4 2006 .SHORT TERM /REST OF TODAY THROUGH TONIGHT/... UPDATED ZONES HAVE BEEN ISSUED TO CLEAR OUT THIS MORNINGS CLOUDS AND SHOWERS FROM CENTRAL AND SOUTHERN VERMONT...AND TO INTRODUCE SLIGHT CHC OF A SHOWER OR THUNDERSTORM IN NORTHERN CHAMPLAIN VLY AND FAR NORTHERN VERMONT LATE THIS AFTERNOON AND INTO EARLY TNGT. BECOMING CONCERNED ABOUT POOL OF SFC DWPTS REMAINING IN THE UPR 60S INST LAWRENCE VLY AHEAD OF SIGNIFICANT SECONDARY SFC COLD FRONT. 12Z NAM AND RUC MODELS SHOW VORT TROF...SFC FRONT...VERTICAL VELOCITY...CAPES ABOVE 1000...AND FAIRLY LIGHT BUT WIDESPREAD PCPN MOVING SEWRD THRU THE OTTAWA VLY AND ST LAWRENCE VLY AND INTO OUR BORDER COUNTIES BY SUNSET. WILL HAVE TO KEEP A CLOSE EYE ON THIS AND MAY HAVE TO INCREASE POPS AND EXTENT OF COVERAGE FOR THESE POSSIBLE THUNDERSTORMS ACROSS MORE OF THE NRN HALF OF THE FORECAST AREA. && .PREV DISCUSSION... /ISSUED 440 AM EDT FRI AUG 4 2006/ SHORT TERM /TODAY THROUGH SATURDAY NIGHT/... COMPOSITE RADAR LOOP SHOWING SOME RAIN SHOWERS EXTENDING FROM NORTHEAST VERMONT DOWN TO SOUTH CENTRAL VERMONT AND THE SOUTHERN CHAMPLAIN VALLEY AT THIS TIME. EXPECT THIS SHOWER ACTIVITY TO COME TO AN END LATE THIS MORNING...WITH SKIES BECOMING PARTLY SUNNY. A HIGH PRESSURE AREA OVER THE UPPER MISSISSIPPI VALLEY EARLY TODAY WILL BUILD EAST AND BE CENTERED OVER THE REGION SATURDAY NIGHT... WITH FAIR AND DRY WEATHER WITH LOWER HUMIDITIES EXPECTED TONIGHT THROUGH SATURDAY NIGHT. GFS MOS MAX TEMPERATURES LOOK A BIT TOO WARM TODAY...SO HAVE UNDERCUT BY ABOUT 2 DEGREES. LONG TERM /SUNDAY THROUGH THURSDAY/... THE HIGH PRESSURE AREA WILL MOVE OFF THE NEW ENGLAND COAST DURING THE DAY ON SUNDAY...WITH WARMER AIR MOVING INTO THE REGION SUNDAY AFTERNOON. MODEL GUIDANCE SHOWING INCREASING MOISTURE MOVING INTO THE REGION LATE SUNDAY NIGHT AHEAD OF A COLD FRONT MOVING SOUTH FROM CANADA. WILL GO WITH CHANCE POPS FOR SHOWERS AND THUNDERSTORMS AFTER MIDNIGHT ON SUNDAY NIGHT. LATEST MODEL GUIDANCE SHOWS A COLD FRONT WILL MOVE SOUTH INTO THE REGION ON MONDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. HIGH PRESSURE TO THEN BUILD SOUTHEAST FROM THE WESTERN GREAT LAKES ON TUESDAY FOR FAIR AND DRY WEATHER TUESDAY THROUGH MOST OF THURSDAY. AVIATION... VFR TO MVFR COND THRU 09Z DUE TO FG/SHRA...ESPECIALLY AT KMPV...GOING ALL VFR AFT 09Z W/ SCT LOW/MID CLDS. NEAR SKC AFT 22Z-00Z. LGT/VAR WINDS THRU 11Z-12Z...BECMG WNW 5-10KTS...THEN LGT/VAR AGAIN AROUND 00Z. HIR TRRN WILL BE OBSCD. NO TAF ISSUED ATTM FOR KSLK DUE TO PROBLEMS W/ OBSERVING EQUIPMENT. WILL RESUME TAF WHEN EQUIPMENT IS UP AND RUNNING. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SHORT TERM...REB vt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 1038 AM MDT FRI AUG 4 2006 .UPDATE... ONLY MINOR CHANGES MADE TO THE SHORT TERM PACKAGE AS FORECAST LOOKS ON TRACK. WEAK SHORTWAVE TROUGH THAT PRODUCED A FEW SHOWERS HAS DEPARTED THE CWA AND A BRIEF PERIOD OF SUBSIDENCE HAS FOLLOWED IN BEHIND. CONVECTIVE TEMPERATURES ARE RATHER LOW IN THE MIDDLE 80S TO NEAR 90...AND LIKEWISE AN INCREASE IN CU HAS BEEN NOTED OVER THE SUNNY REGIONS OF THE NORTHWESTERN CWA AS READINGS HAVE ALREADY REACHED CONVECTIVE TEMPS. SURFACE FORCING AND MID LEVEL LAPSE RATES DONT LOOK ESPECIALLY GOOD THIS AFTERNOON...ALTHOUGH CONTINUED SURFACE HEATING AND ANY REMNANT BOUNDARIES FROM EARLIER CONVECTION SHOULD ALLOW FOR WIDELY SCATTERED THUNDERSTORMS TO DEVELOP THIS AFTERNOON. DIRECTIONAL AND SPEED SHEAR LOOK SUPPORTIVE OF MORE ORGANIZED ACTIVITY. IN ADDITION...H7 DEWPOINTS AND THETA-E PROFILE SUGGESTS THAT AN ISOLATED SEVERE MICROBURST IS POSSIBLE WITH THE STRONGEST/MOST PERSISTENT STORMS THIS AFTERNOON...MAINLY NORTH OF THE INTERSTATE 70 CORRIDOR WHERE INSTABILITY WILL BE GREATEST. OTHERWISE...MADE MINOR CHANGES TO DEWPOINTS AND SKY COVERAGE TO BETTER REFLECT CURRENT TRENDS. DECENT PRESSURE GRADIENT THIS AFTERNOON...SO WILL LIKELY SEE SOME SOUTH-SOUTHEAST WIND GUSTS UP TO 30 MPH. NO OTHER CHANGES MADE IN THE SHORT TERM. BLAIR && .PREV DISCUSSION... (ISSUED 220 AM MDT FRI AUG 4 2006) DISCUSSION...FORECAST CONCERNS ARE ON TEMPERATURES AND PRECIPITATION CHANCES THE NEXT SEVERAL DAYS. TODAY/TONIGHT...LIGHT TO MODERATE SHOWERS HAVE FINALLY DEVELOPED WITHIN THE PAST HOUR ACROSS THE SOUTH AND SOUTHEAST PORTIONS OF THE FORECAST AREA WHERE DEEPER 700-500 MOISTURE AND SOME WEAK LIFT IS NOTED BY THE RUC. 06Z NAM QPF HAS A GOOD HANDLE ON CURRENT ACTIVITY WHEN COMPARED TO RADAR SO HAVE RUN WITH IT FOR THE FIRST PERIOD POP/WX GRIDS. AS THIS FEATURE MOVES THROUGH THE CENTRAL AND EASTERN PARTS OF THE FORECAST AREA THIS MORNING AND AFTERNOON ANOTHER WILL ROTATE TOWARD THE FRONT RANGE LATE IN THE DAY. NOT A LOT IN THE WAY OF CONVECTIVE INHIBITION TODAY WITH SOME CAPE AVAILABLE. MID LEVEL LAPSE RATES/LIFT NOTHING TO WRITE ABOUT. THINGS SHOULD DIE OFF QUICKLY WITH THE LOSS OF DAYTIME HEATING SO NO POPS/WX TO WORRY ABOUT. SATURDAY/SATURDAY NIGHT...AN UPPER LEVEL LOW WILL MOVE EAST ALONG THE US/CANADIAN BORDER SATURDAY AFTERNOON ITS TROUGH AXIS AND ASSOCIATED COLD FRONT MOVING INTO PORTIONS OF THE AREA. THE EXACT LOCATION OF THE FRONT WILL BE CRUCIAL TO WHERE AFTERNOON THUNDERSTORMS DEVELOP. RIGHT NOW IT APPEARS THE NORTHWEST 1/3-1/4 OF THE AREA WOULD HAVE THE BETTER CHANCE OF AFTERNOON PRECIPITATION. CURRENT FORECAST HAS SOME SLIGHT CHANCE POPS GOING SO ONLY MODIFICATIONS WILL BE TWEAKING AND INCREASING COVERAGE A BIT ACROSS SOME NORTHWEST KANSAS AND SOUTHWEST NEBRASKA COUNTIES. THE FRONT AND ASSOCIATED AXIS OF MID LEVEL MOISTURE DOESNT MOVE MUCH SATURDAY NIGHT AND CURRENT FORECAST HAS THIS LINED OUT PRETTY WELL. ONLY SLIGHT ADJUSTMENTS NEED TO BE MADE. SUNDAY/SUNDAY NIGHT...MID LEVEL MOISTURE AXIS REMAINS ACROSS THE COLORADO FRONT RANGE AND POINTS WEST WHERE CHANCES OF AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. CURRENT GRIDS HAVE SLIGHT CHANCE POPS FOR FAR EASTERN COLORADO WHICH MATCH WELL WITH BETTER MOISTURE AND 0-6KM WINDS FROM THE SOUTHWEST. SO...WILL LEAVE THESE GRIDS AS IS. THE ABOVE MENTIONED MOISTURE AXIS PUSHES INTO THE NORTHWEST 1/3 OR SO OF THE FORECAST AREA AND GFS/NAM GENERATE SOME LIGHT QPF. WILL GO AHEAD AND ADD SOME SLIGHT CHANCE POPS IN THIS AREA AS A RESULT. MONDAY-TUESDAY...UPPER PATTERN DOESNT CHANGE A WHOLE LOT FROM PREVIOUS DAYS AS HIGH PRESSURE REMAINS ACROSS THE CENTRAL PLAINS. AXIS OF MID LEVEL MOISTURE REMAINS ACROSS THE NORTHWEST 1/2 OF THE AREA OR SO...MOST FAVORABLE IN THE FAR NORTHWEST. THIS IS WHERE BETTER CHANCES OF PRECIPITATION WILL BE POSSIBLE. WILL KEEP HIGHEST SILENT POPS ACROSS THIS AREA. 850 TEMPERATURES FROM THE GFS/ECMWF FAVOR HIGHS CLOSE TO LATEST MEX GUIDANCE SO WILL UP CURRENT FORECAST A FEW DEGREES. WEDNESDAY-THURSDAY...UPPER HIGH REMAINS IN PLACE AND 850 TEMPERATURES AT OR SLIGHTLY ABOVE 30C ACROSS THE AREA. 90S AND A FEW 100S EXPECTED AND HAVE INCREASED PREVIOUS FORECAST TEMPERATURE GRIDS A BIT MORE GIVEN THE GOOD CONSISTENCY AND LATEST MEX GUIDANCE. .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 404 PM EDT FRI AUG 4 2006 .DISCUSSION... CURRENTLY...LATEST WV IMGRY/RUC ANYSIS SHOWS WEAK UPPER LEVEL RIDGE OVER CENTRAL CONUS WITH SFC REFLECTION OVER UPPER GREAT LKS...AS WELL AS DEVELOPING LOW PRESSURE OVER WESTERN NORTHERN PLAIN STATES. THIS LOW WILL BE THE MAIN DISTURBANCE AFFECTING THE FORECAST OVER THE NEXT FEW DAYS. SHORT TERM...TONIGHT THRU EARLY SAT AFTN...MAIN CONCERN IS THE CHANCE FOR SHOWERS AND THUNDERSTORMS. LATEST GUIDANCE...NAM/GFS/RUC SUGGEST BEST CHANCES FOR DEVELOPMENT WILL BE ACROSS THE WEST AND NORTH...WEST OF A LINE FROM SHOT POINT TO IMT. THIS AREA CORRESPONDS TO THE BEST MID LEVEL MOISTURE AS WELL AS INSTABILITY...850-500 DTHTA/DZ. COULDN'T RULE OUT PRECIP. FOR KSAW...SO USED A PROB 30 GROUP TO HIGHLIGHT LESSER CHANCE THAN KCMX. FOR TOMORROW AFTN...MAIN CONCERN WILL BE DWPT/RH'S ACROSS WEST AND NORTH. CURRENT GRIDS HAVE RHS IN THE MID 30S...A BIT HIGHER ACROSS THE KEWEENAW. WITH INCREASING SOUTHERLY FLOW AHEAD OF SUNDAY'S S/W AND TEMPS IN THE MID TO UPR 80S...FIRE WX ISSUES AREN'T OUT OF THE QUESTION. DESPITE RECENT RAINFALL ACROSS THE U.P. AREAS OF SOUTHERN HOUGHTON COUNTY...PIEM4...REMAIN IN HIGH FIRE RISK...SEE MICFFDRS FIRE DANGER FCST FOR SPECIFICS. LONG TERM...SAT AFTERNOON AND ON...SHOWER AND THUNDERSTORM ACTIVITY SHOULD INCREASE THROUGH THE LATE SAT AFTERNOON AND EVENING HOURS AS THETA-E RIDGE AND LOW SHOWALTER AXIS APPROACH THE WESTERN CWA. EXPECT THE BEST COVERAGE/INTENSITY TO OCCUR SAT NIGHT FOR THE WESTERN PORTIONS OF THE CWA...AND LINGER INTO SUN MORNING FOR THE CENTRAL AND EASTERN CWA. WOULD EXPECT THE MAIN FOCUS OF CONVECTION TO OCCUR ALONG THE NARROW INSTABILITY AXIS WHERE MUCAPE VALUES RISE TO 1000 TO 1500 J/KG...THOUGH STORM INTENSITY AND QPF MIGHT NOT AMOUNT TO MUCH GIVEN THE WRONG TIME OF DAY...SHOULD MOISTURE ADVECTION NOT PAN OUT...AND IF THE SYSTEM WRAPS UP TOO MUCH. SPC DAY TWO OUTLOOK SHOWS BEST CHANCE FOR SEVERE WEATHER TO STAY TO THE WEST...BUT WOULD NOT RULE OUT AN ISOLATED SEVERE STORM LATE SAT NIGHT INTO EARLY SUN...ESPECIALLY SUN MORNING FOR THE SOUTH-CENTRAL AND EASTERN CWA GIVEN THE INSTABILITY PRESENT...POSSIBLE DIURNAL EFFECTS...AND THE STRONG MID-LEVEL WINDS DEPICTED SUN MORNING. MODELS INDICATE A DRYING TREND BEHIND THE FRONT SUN AFTERNOON WITH A DECENT WESTERLY FLOW DEVELOPING FOR THE AFTERNOON AND EVENING HOURS. THIS CREATES SOME CONCERN FOR DOWNSLOPE AREAS FAVORED BY WEST WINDS AS THE MAIN COLD AIR ADVECTION DOES NOT ARRIVE UNTIL SUN NIGHT...AND POST-FRONTAL WINDS LOOK TO BE FAIRLY GUSTY SUN AFTERNOON SO MIXING WOULD BE IDEAL. HAVE INCREASED HIGH TEMPS ON SUN FOR THESE AREAS A FEW DEGREES INTO THE MID 80S...BUT LATER FCSTS MAY HAVE TO WATCH FOR UPPER 80S...ESPECIALLY ALONG THE GREEN BAY SHORELINE. HIGH PRES BUILDS INTO THE UPPER MIDWEST AND UPPER GREAT LAKES FOR MON AND MON NIGHT...THEN LINGERS THROUGH THE MID WEEK. ONLY WEATHER CONCERNS FOR EARLY NEXT WEEK WOULD BE TEMPS...AS LIGHT PRES GRADIENT MAY ALLOW FOR WEAK LAKE BREEZES DURING THE AFTERNOON...AND GOOD RADIATIONAL COOLING AT NIGHT. HAVE NOT CHANGED MUCH OF THE FCST HERE OTHER THAN LOWER THE OVERNIGHT LOWS A FEW DEGREES...ESPECIALLY MON NIGHT WHEN THE SURFACE HIGH BECOMES MORE CENTERED OVER THE CWA. IN THE EXTENDED...QUIET WEATHER LOOKS TO BE THE RULE FOR MOST OF NEXT WEEK AS SURFACE HIGH PRES BUILDS OVER THE UPPER GREAT LAKES FOR MON AND TUE...AND REMAIN OVER THE REGION THROUGH WED BEFORE SLIDING SOUTHEAST AS LOW PRES ONCE AGAIN DEVELOPS OVER THE PLAINS. NOT MUCH COOLING IS EXPECTED WITH THE HIGH DURING THE DAY...SO MAX TEMPS LOOK TO REMAIN IN THE UPPER 70S TO LOWER 80S FOR THE MOST PART...WITH A GRADUAL WARMING TREND THROUGH THE WEEK. NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS IS LATE IN THE WEEK WHEN MODELS INDICATE A SHORTWAVE MOVING THROUGH THE REGION...THOUGH THERE ARE SIGNIFICANT DIFFERENCES IN THE TIMING OF THIS SYSTEM. FOLLOWING A GENERAL CONSENSUS AND PER HPC GUIDANCE...HAVE WENT WITH LOW CHANCE POPS FOR THU AFTERNOON INTO FRI GIVEN THE UNCERTAINTY...AND THE WEAK FRONTAL PASSAGE DEPICTED/EXPECTED. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE && $$ SHORT TERM...PEARSON LONG TERM...LAROSA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 300 PM CDT FRI AUG 4 2006 .SHORT TERM...CHALLENGES TO REVOLVE AROUND CONVECTIVE CHANCES THROUGH SAT EVENING. 12Z MODELS IN GOOD AGREEMENT WITH SYNOPTIC FIELDS...BUT LACK IN DETAILS. MAIN IDEA IS FOR A STRONG SHORTWAVE TO PROPAGATE ACROSS S CANADA LOCATED NEAR LAKE WINNIPEG BY 00Z SUN. AS THIS WAVE APPROACHES THE REGION WILL BE UNDER THE INFLUENCE OF A 35-40KT 850MB JET. DEPENDING ON WHERE STRONGEST BAROCLINIC ZONES EXIST (STRONGEST WARM AIR ADVECTION) SHOWERS/THUNDER REMAIN POSSIBLE UNTIL THE COLD FRONT PASSES SAT AFTERNOON. HIGH PRESSURE THEN GAINS HOLD OF THE REGION FOR SUN-MON WITH TEMPS NEAR NORMAL. TONIGHT...ACTIVITY CURRENTLY ALONG INTERNATIONAL BORDER IN MN CONTINUES TO SLOWLY WORK EASTWARD. 50-60KT DEEP LAYERED SHEAR HAS MADE UP FOR MARGINAL INSTABILITY KEEPING STORMS NEAR SEVERE LIMITS. THESE STORMS WILL BEAR WATCHING...BUT AS THEY MOVE AWAY FROM BEST INSTABILITY DO NOT EXPECT MUCH MORE STRENGTHENING. ACTIVITY ACROSS THE S FA IS LIKELY TO CONTINUE AND SLOWLY PROPAGATE N-NE. MAIN CONCERN FOR SEVERE POTENTIAL THIS EVENING WILL BE ACROSS W FA. INSTABILITY AXIS ACROSS CENTRAL ND (BRUSHING OUR E FA) HAS SET UP WITH MLCAPES AROUND 2000 J/KG. QUESTION IS WHETHER OR NOT STORMS WILL INITIATE. RUC SOUNDING SHOWS CONVECTIVE TEMPS NEAR 90F. WARM FRONT REMAINS ALONG A DVL-GFK-BJI LINE. BEST CONVERGENCE AND INSTABILITY EXIST ACROSS DVL BASIN...AND WITH DEEP LAYER SHEAR UP TO 40KTS SEVERE POSSIBLE IF STORMS INITIATE. SAT...CONDITIONS ARE SETTING UP FOR A SIGNIFICANT SEVERE WX EVENT. SWODY2 EXPLAINS THE SCENARIO VERY WELL...SEE FOR DETAILS. WITH STRONG DYNAMICS EXPECTED WILL MENTION SEVERE STORMS ALONG AND E OF VALLEY FOR SAT AFTERNOON/EVENING. ONLY CHANGE PAST SAT WAS TO ADD ISOLD SHOWERS ACROSS NW MN SUN MORNING AS SHORTWAVE PASSES JUST E. RAIN THAT DEVELOPED ACROSS SE ND HAS KEPT FIRE WX CONDITIONS FROM BECOMING CRITICAL. CONDITIONS ACROSS THE DVL BASIN WILL BE NEAR CRITICAL AS DEWPOINTS DROP AND WINDS INCREASE BEHIND THE COLD FRONT. .LONG TERM...(TUE THROUGH FRI)...LONG RANGE MODELS ARE SIMILAR...BUT DO HAVE SOME TIMING DIFFERENCES. 500MB RIDGE REMAINS OVER THE AREA. A WAVE MOVES THROUGH THE 500MB FLOW ON TUE NIGHT AND WED... ACCOMPANIED BY A SURFACE LOW PRESSURE SYSTEM...SO KEPT THE CHANCE OF THUNDERSTORMS IN THE FORECAST. THE 500MB RIDGE MOVES E OF THE AREA BY 12Z FRI...AS A 500MB TROF APPROACHES...SO INCLUDED A SLIGHT CHANCE FOR THUNDERSTORMS IN PARTS OF THE AREA FOR FRI. AS FAR AS TEMPS...EXPECT TEMPERATURES TO WARM TO ABOVE NORMAL. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG/NG nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 420 PM EDT FRI AUG 4 2006 .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...A HOT...HUMID AND UNSTABLE ENVIRONMENT HAS SPAWNED NUMEROUS THUNDERSTORMS ACROSS THE CWA THIS AFTERNOON. RUC SHORT TERM FORECAST FIELDS SHOWS SEVERAL WEAK VORT MAXES OVER CENTRAL NC AND SC...WHICH MAY BE ASSISTING THE INITIATION AND MAINTENANCE OF THESE STORMS. LAPS ANALYSIS INDICATES HIGH CAPE VALUES OVER SOUTHEAST GA AND SC...SO WOULD EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO CONTINUE THROUGH THE AFTERNOON AND EVENING. WILL ALLOW HEAT ADVISORY TO CONTINUE UNTIL 8PM TONIGHT. OBSERVATION SITES THAT HAVE NOT YET SEEN RAINFALL AND THUNDERSTORM ACTIVITY...SUCH AS SAVANNAH...ARE STILL REPORTING HEAT INDICES ABOVE 105 DEGREES. PERSISTENT LEE TROUGH WILL REMAIN EAST OF THE APPALACHIANS TONIGHT AND SATURDAY...AS A WEAK FRONTAL BOUNDARY MOVES SOUTHEAST TOWARD THE FORECAST AREA. BOTH NAM AND GFS SHOW THE SURFACE BOUNDARY DROPPING SOUTH THROUGH THE CWA SATURDAY MORNING...THEN STALLING OUT APPROXIMATELY OVER THE SC/GA BORDER. WITH THE PROXIMITY OF THE WEAK FRONT...EXPECT ISOLATED SHOWER AND THUNDERSTORM ACTIVITY TO BE ABLE TO PERSIST TONIGHT. MORE EXTENSIVE AFTERNOON CONVECTIVE COVERAGE IS EXPECTED ON SATURDAY COMPARED TO PREVIOUS DAYS. WILL MAINTAIN SLIGHT CHANCE POPS OVERNIGHT...INCREASING TO CHANCE POPS SATURDAY AFTERNOON AND EVENING. HEAT INDICES UP TO 105 DEGREES ARE AGAIN POSSIBLE SATURDAY AFTERNOON...WITH HIGH TEMPERATURES REACHING THE MID 90S IN MOST LOCATIONS AWAY FROM THE IMMEDIATE COAST AND DEWPOINTS LINGERING IN THE MID 70S. WILL CHOOSE NOT TO ISSUE A HEAT ADVISORY FOR TOMORROW AT THIS POINT...SINCE COVERAGE AND DURATION OF HIGHEST INDICES APPEARS TO BE LESS ON SATURDAY THAN TODAY. && .LONG TERM /SUNDAY THROUGH FRIDAY/...MEDIUM RANGE GUIDANCE IS IN FAIRLY GOOD AGREEMENT WITH SFC AND UPPER LEVEL FEATURES THROUGH THE EXTENDED PERIOD THIS AFTERNOON. UPPER RIDGE WILL BEGIN TO BUILD ACROSS THE SE CONUS SUN THROUGH TUE...BEFORE RETROGRADING WESTWARD INTO THE LOWER MS VALLEY WED THROUGH FRI. AT THE SURFACE...FRONTAL BOUNDARY WILL DISSIPATE OVER THE AREA SUN...WITH HIGH PRESSURE BUILDING BACK INTO THE REGION FOR THE FIRST HALF OF THE UPCOMING WORK WEEK. AS UPPER LEVEL HEIGHTS LOWER BY MID WEEK...A WEAK FRONTAL BOUNDARY WILL APPROACH THE REGION WED AND STALL OUT OVER THE AREA ON THU. HIGH PRESSURE WILL THEN GET RE-ESTABLISHED FOR FRI. AS FOR SENSIBLE WEATHER...WILL CONTINUE LOW CHC/SLGT CHC POPS EACH DAY THROUGH THE EXTENDED PERIOD. TEMPERATURES WILL REMAIN SLIGHTLY ABOVE CLIMO THROUGH THE PERIOD. && .AVIATION...INCLUDED A TEMPO GROUP FOR TSRA IN THE KCHS TAF AS AN INTENSE STORM PASSED OVER THE TERMINAL. THE TEMPO GROUP EXPIRES AT 21Z...AND IT LOOKS LIKE A VCTS WILL BE SUFFICIENT AT THIS POINT. THUNDERSTORMS HAVE BEEN POPPING UP IN THE VICINITY OF KSAV...BUT NOTHING HAS FORMED OVER THE TERMINAL YET. WILL ALSO MAINTAIN VCTS AT KSAV TO ACCOUNT FOR ONGOING CONVECTION NEARBY. EXPECT CONVECTION TO DIMINISH DURING THE EVENING. SOUTH TO SOUTHWEST WINDS BEHIND THE SEABREEZE FRONT WILL ALSO DIMINISH OVERNIGHT AT BOTH TERMINALS. && .MARINE...SURFACE TROUGH WILL REMAIN OVER THE SOUTHEAST GA AND SC COASTAL WATERS TONIGHT THROUGH SATURDAY. A WEAK SURFACE BOUNDARY WILL DROP SOUTH THROUGH THE SOUTH CAROLINA MARINE ZONES...STALLING APPROXIMATELY OVER THE SC/GA LINE. THUS WINDS IN THE SC MARINE ZONES WILL TURN BRIEFLY NORTHWESTERLY SATURDAY...BEFORE SEABREEZE EFFECTS VEER THE WINDS AROUND TO SOUTHERLY. OTHERWISE...WINDS WILL BE AOB 15 KNOTS WITH SEAS AOB 3 FT. TRANQUIL CONDITIONS ARE EXPECTED TO BE THE RULE ACROSS THE WATERS SUN THROUGH WED...WITH HIGH PRESSURE REMAINING THE DOMINANT WEATHER FEATURE. WINDS ARE EXPECTED TO REMAIN AOB 15 KT...WITH SEAS AOB 4 FT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...HEAT ADVISORY FOR GAZ087-088-099>101-114>119-137>141 UNTIL 8 PM TONIGHT. SC...HEAT ADVISORY FOR SCZ040-042>045-047>051 UNTIL 8 PM TONIGHT. MARINE...NONE. && $$ 79/JRJ sc