AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 930 AM PDT SUN JUL 23 2006 .SHORT TERM...NO CHANGE IN THE CURRENT WEATHER PATTERN THIS MORNING AS THE STRONG UPPER RIDGE CONTINUES TO DOMINATE THE WEST. MAY SEE RECORD TEMPERATURES AGAIN THIS AFTERNOON AS MORNING LOWS OVER THE LOWER ELEVATIONS WERE ONLY ABLE TO REACH THE UPPER 80S. AT 800 AM... VALLEY LOCATIONS HAD READINGS IN THE 90S...KFAT AT 98...AND EXPECTED TO CONTINUE RISING THROUGH OUT THE DAY. LATEST WATER VAPOR IMAGERY ALONG WITH RUC80 ANALYSIS SHOWS EVEN MORE MOISTURE PUSHING INTO THE REGION UNDER AS SOUTHEASTERLY FLOW ALOFT. THEREFORE...WITH CAPE VALUES RISING BACK UP TO AROUND 1500J/KG...WILL SEE ANOTHER DAY OF THUNDERSTORMS. AGAIN...AS MORE MOISTURE CONTINUES TO PUSH IN...THE POTENTIAL FOR FLASH FLOODING WILL REMAIN OVER THE MOUNTAINS. WILL THEREFORE...ALLOW THE FLASH FLOOD WATCH TO REMAIN IN EFFECT UNTIL 9 PM TONIGHT. THE HEAT AND HUMIDITY COMBINED WILL A FACTOR TODAY AS HEAT INDEXES REACH BACK INTO THE +110 DEG-F RANGE. WILL ALSO ALLOW THE HEAT ADVISORY TO REMAIN IN EFFECT TODAY AS RECORD TEMPERATURES MAY BE OBSERVED. && .AVIATION...ISOLATED TO SCATTERED THUNDERSTORMS WILL OCCUR OVER THE SOUTHERN SIERRA NEVADA AS WELL AS THE KERN COUNTY MOUNTAINS AND DESERT FROM 19Z SUNDAY TO 07Z MONDAY. OTHERWISE...VFR CONDITIONS WILL PREVAIL THROUGH 12Z MONDAY. DUE TO UNUSUALLY HIGH TEMPERATURES...HIGH DENSITY ALTITUDES CONTINUE TO PREVAIL ACROSS THE AREA...ESPECIALLY AT THE HIGHER ELEVATION AIRPORTS. FOR SPECIFIC DETAILS...PLEASE REFER TO TAFS FOR KMCE...KFAT...AND KBFL. && .HNX WATCHES/WARNINGS/ADVISORIES...HEAT ADVISORY UNTIL 9 PM TODAY FOR THE CENTRAL AND SOUTHERN SAN JOAQUIN VALLEY AND ADJACENT SIERRA NEVADA FOOTHILLS. ...FLASH FLOOD WATCH FROM NOON UNTIL 9 PM PDT TODAY FOR HIGHER ELEVATIONS OF THE SOUTHERN SIERRA NEVADA AND THE TEHACHAPI MOUNTAINS. && $$ MOLINA ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 945 PM MDT SUN JUL 23 2006 .DISCUSSION... WATER VAPOR IMAGERY INDICATING SHORT WAVE TROUGH SLIDING ACROSS THE NEBRASKA AND WYOMING BORDER. LARGE AREA OF CONVECTION HAS DEVELOPED AHEAD OF THIS FEATURE...AND IS SLOWLY MOVING SOUTHEAST. NONE OF THE SHORT RANGE MODELS REALLY PICKING UP ON SITUATION WELL. NAM/RUC INHIBITION FIELDS INDICATE STORMS SHOULD MAKE IT INTO CWA...BUT SOUTHERN EXTENT REMAINS QUESTIONABLE. HAVE UPDATED POPS TO ACCOUNT FOR THIS...BUT DUE TO UNCERTAINTY WITH SOUTHERN EXTENT WILL KEEP POPS LOW. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ JRM ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 245 PM EDT SUN JUL 23 2006 .SHORT TERM (TONIGHT THROUGH MONDAY AFTERNOON)... UPPER LEVEL TROUGH ACROSS SE CANADA INTO THE SPINE OF THE SOUTHERN APPALACHIANS THIS AFTERNOON CONTINUES TO TRACK EAST TOWARDS NEW ENGLAND...AS SFC HIGH REMAINS TO THE WEST OF THE FORECAST AREA CENTERED NEAR THE MO/KS LINE. CURRENT RUC SHOWING H500 TEMPS WARMING SO FAR TODAY ABOUT 5C...AND H850 TEMPS ABOUT 3C...THIS WARMING ALOFT HAS LESSENED LAPSE RATES ENOUGH TO KEEP ANY SIGNIFICANT CU BUILD UP INTO THIS EVENING. SINKING MOTION ACROSS THE SOUTHERN WABASH VALLEY EAST INTO THE FORECAST AREA WHERE MID LEVEL WINDS HAVE AN ANTICYCLONIC FLOW OVER THE AREA HAS KEPT MOST OF THE WESTERN HALF OF THE CWA NEARLY CLOUD FREE...SCTD CU FIELD ACROSS THE EAST AND SOUTH. TEMPS ARE ONLY FORECAST CHALLENGE IN THE SHORT TERM...AND WITH LITTLE VARIANCE IN MOS IT SEEMS NOT MUCH OF ONE AT THAT. TONIGHT CU WILL DISSIPATE COMPLETELY...AND LIGHT WINDS AS THE SFC HIGH MOVES ACROSS THE FORECAST AREA. BELIEVE THAT PATCHY FOG WILL BE LIMITED TO LOW LYING AREAS...VALLEYS...AND NEAR WATERWAYS ACROSS THE EASTERN HALF OF THE FORECAST AREA...WITH SLIGHTLY DRIER AIR ACROSS THE WEST. HAVE LEANED TOWARDS THE UPPER END OF MOS WITH LOWS DROPPING INTO THE LOWER AND MIDDLE 60S. WEAK SFC HI JUST TO THE EAST OF THE REGION WILL ALLOW FOR LIGHT WINDS...WITH A SLIGHT SOUTHERLY COMPONENT POSSIBLE. FORECAST SOUNDINGS SHOW DRY AIR THROUGH THE ENTIRE COLUMN...AS DO TIME SERIES OF EACH TAF SITE...FEW CU WILL DEVELOP AT BEST ACROSS THE REGION ON MONDAY AFTERNOON. WITH H850 TEMPS CLIMBING ANOTHER 1 TO 2C...HAVE KEPT TEMPS ON THE LOWER SIDE OF MOS IN THE MIDDLE TO UPPER 80S ACROSS THE FORECAST AREA. --SCHOTT .LONG TERM (MONDAY NIGHT THROUGH SUNDAY THE DEEP UPPER TROUGH CURRENTLY OVER THE REGION WILL LIFT TO THE NORTHEAST BY THE BEGINNING OF THIS FORECAST PERIOD. WE WILL STAY IN A WEAK NORTHWEST FLOW EARLY IN THE WEEK AS A COUPLE OF S/W'S MOVE THROUGH THE FLOW. HOWEVER THE UPPER LEVEL RIDGE WILL REASSERT ITSELF LATE IN THE WEEK. AT THE SURFACE WE WILL SEE A COUPLE OF COOL FRONTS DROP INTO ILLINOIS AND INDIANA BUT THEY WILL REMAIN NORTH OF OUR FORECAST AREA. SURFACE HIGH PRESSURE WILL DRIFT FROM THE LOWER OHIO VALLEY MONDAY TO THE EAST COAST WEDNESDAY. THIS WILL ALLOW A RETURN MOIST SOUTHWEST FLOW WITH SCATTERED THUNDERSTORMS EXPECTED THURSDAY THROUGH SATURDAY. CURRENT FORECAST TEMPERATURES ARE RUNNING 3 TO 5 DEGREES ABOVE NORMAL FOR LATE JULY AND LOOK GOOD. NO CHANGES ARE PLANNED HERE. --JA .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 1006 AM CDT SUN JUL 23 2006 .DISCUSSION... RATHER DIFFUSE FRONTAL BOUNDARY AS OF 14Z APPEARS TO BE LOCATED NEAR A MCB...TYR...CRS LINE AND IS NEARLY STATIONARY. CONVECTION EARLY THIS MORNING HAS DIED OFF BUT ELEVATED INSTABILITY EXISTS ALONG AN 850MB THETAE BOUNDARY BEST INDICATED BY THE RUC40 WHICH SHOWS THE BOUNDARY ACROSS OUR SOUTHERN PARISHES AND THEN SWINGS NORTHWARD IN THE PINEY WOODS OF NE TX. LATEST LAPSE ANALYSIS SHOWS GROWING CAPE AS OF 14Z NEAR 1000 J/KG ALONG AND SOUTH OF THE FRONTAL BOUNDARY. PWATS IN THIS AREA PUSHING 1.75" WITH MUCH DRIER AIR TOWARDS S AR...PERHAPS WITH PWATS NEAR 1.25". CURRENT FCST HAS CHANCE POPS ALONG AND SOUTH OF THE CURRENT FRONTAL BOUNDARY POSITION AND THIS LOOKS GOOD. WITH ADDITIONAL HEATING...EXPECT SCATTERED CONVECTION TO ONCE AGAIN DEVELOP IN THE VICINITY OF THE FRONTAL/850MB THETAE BOUNDARIES. STEERING CURRENTS ARE WEAK AT BEST SO ANY CONVECTION THAT DEVELOPS WILL LIKELY RESULT IN LOCALLY HEAVY RAINFALL TOTALS. WILL UPDATE TO CLEAN UP SOME WORDING ISSUES BUT NO OTHER SIGNIFICANT CHANGES EXPECTED ATTM. UPDATE OUT SHORTLY. 13 && .PRELIMINARY POINT TEMPS/POPS... SHV 92 67 95 72 / 0 0 0 0 MLU 91 67 94 71 / 0 0 0 0 DEQ 92 62 95 66 / 0 0 0 0 TXK 93 65 95 71 / 0 0 0 0 ELD 91 62 95 69 / 0 0 0 0 TYR 92 69 95 73 / 30 0 0 0 GGG 92 67 95 72 / 30 0 0 0 LFK 92 69 92 72 / 30 20 20 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 13 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 340 PM EDT SUN JUL 23 2006 .SYNOPSIS...LOW PRESSURE MOVING THROUGH THE MARITIMES WILL PUSH A COLD FRONT OFF THE COAST THIS EVENING. ANOTHER AREA OF LOW PRESSURE WILL LIFT ALONG THE FRONT TOWARD NOVA SCOTIA LATER TONIGHT. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD IN WHILE AN UPPER LEVEL DISTURBANCE MOVES THROUGH THE REGION DURING MONDAY. A SERIES OF FRONTAL SYSTEM APPROACHING WILL KEEP CONDITIONS UNSETTLED THROUGH MID WEEK. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... LATEST RUC ANALYSIS LIFTS A PIECE OF ENERGY WITHIN THE SOUTHWEST FLOW ALOFT THROUGH THE REGION EARLY TONIGHT. WILL KEEP SLIGHT CHANCE TO CHANCE POPS OVER THE CWA EARLY TONIGHT...THEN SLOWLY DIMINISH AFTER 06Z EXCEPT FOR THE COAST WHERE ANOTHER LOW LIFTING NORTH TOWARD NOVA SCOTIA WILL KEEP CHANCE POPS OVERNIGHT. MESOANALYSIS FIELDS SUGGEST ATMOSHPERE IS FAIRLY STABLE WITH LI'S AOA PLUS TWO AND MID LEVEL LAPSE RATES RATES ONLY AROUND FIVE DEG...SO WILL NOT INCLUDE MENTION OF THUNDERSTORMS FOR TONIGHT. SURFACE LOW MOVES THROUGH THE MARITIMES ALLOWING WEAK SURFACE RIDGE TO BUILD IN DURING THE DAY. ALOFT...RATHER STRONG SHORT WAVE MOVES ACROSS THE REGION ESPECIALLY AROUND THE MAX HEATING TIME OF DAY. INCREASED SURFACE INSOLATION INTERACTING WITH COLD POOL ALOFT DESTABILIZES ATMOSPHERE. HIGHEST CAPE/LOWEST LI'S OCCUR OVER NORTHERN AREAS...SO HAVE HAVE HIGHEST POPS NORTH AND WEST AND MINIMAL CHANCE DOWNEAST FOR MONDAY. SHORT WAVE RIDGE KEEP CONDITIONS QUIET FOR A TIME MONDAY NIGHT... THEN INCREASED WAA AND AN APPROACHING WARM FRONT WILL REINTRODUCE CLOUDS AND -SHRA/-TSRA LATE MONDAY NIGHT AND TUESDAY. WITH WARM FRONT IN THE VICINITY OR JUST TO THE NORTH WILL KEEP POPS GOING FOR TUESDAY NIGHT. LEANED WITH MATCH GUIDANCE ALONG WITH A FEW ADJUSTMENTS FOR TEMPS/DEW POINTS WITHIN THE SHORT TERM. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... THE PATTERN WILL REMAIN RATHER UNSETTLED THROUGH THE LONG TERM PORTION OF THE FORECAST. A MORE OR LESS ZONAL FLOW WILL CONTINUE THROUGH THE PERIOD. PIECES OF ENERGY ROTATING THROUGH THE FLOW WILL RESULT IN THE CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. THE BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE ACROSS NORTHERN AREAS CLOSER TO A FRONTAL BOUNDARY THAT WILL BE NEARLY STATIONARY JUST NORTH OF THE MAINE BORDER INTO FRIDAY. A COLD FRONT WILL APPROACH FROM THE WEST TOWARD THE END OF THE WEEK KEEPING THE CHANCE FOR SHOWERS AND THUNDERSTORMS INTO NEXT WEEKEND. && .AVIATION... MVFR CONDITIONS (CIGS/VSBYS) WILL DOMINATE FOR THE TAF SITE TONIGHT. EXPECT VFR CONDITION TO RETURN DURING TUESDAY MORNING. .MARINE... SHORT TERM: WILL CONTINUE THE SCA WITH SEAS AVERAGING IN THE 4 TO 7 FT RANGE ATTM. AS WEAK SURFACE RIDGE BUILDS IN BEHIND SURFACE LOW LIFTING ACROSS NOVA SCOTIA..EXPECT SEAS TO SUBSIDE DURING MONDAY AFTERNOON AND REMAIN INTO TUESDAY. AS GRADIENT TIGHTENS SEAS SHOULD APPROACH/REACH SCA CRITERIA TUESDAY NIGHT. LONG TERM: NO HEADLINES EXPECTED IN THE LONG TERM. TOOK A FOOT OR TWO OFF THE WAVEWATCH WHICH LOOKED A BIT ON THE HIGH SIDE. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY FOR ANZ050 UNTIL 3 PM MONDAY. && $$ SHORT TERM/MARINE...FITZSIMMONS LONG TERM/MARINE...DUDA AVIATION...FITZSIMMONS me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 952 PM EDT SUN JUL 23 2006 .UPDATE...CURRENT WATER VAPOR/IR SAT/SURFACE/RADAR ANALYSIS SHOWS A WARM FRONT LAID OUT IN A NORTH/SOUTH ORIENTATION ACROSS NORTHERN MINNESOTA...NORTHWARD INTO SOUTHWEST ONTARIO. THIS FRONT INTERSECTS A COLD FRONT DROPPING SOUTHWARD ACROSS THE SOUTHERN CANADIAN PROVINCES. A BAND OF MID TO HIGH LEVEL CLOUDS...ASSOCIATED WITH THE WARM FRONT LIE ACROSS THE UP...AND NOW ENTERING INTO NORTHERN LOWER MICHIGAN. A FEW LIGHT RETURNS HAVE BEEN SHOWING UP ON MQT/APX RADARS...BUT HAS BEEN FALLING APART AS IT TRIES TO WORK INTO NORTHERN MICHIGAN WITH ABUNDANT DRY AIR IN THE LOWER LEVELS. REGARDLESS...WILL THROW IN A MENTION OF SPRINKLES INTO NORTHWEST LOWER MICHIGAN BEGINNING AT 6Z AS SOME LIGHT PRECIP MAY REACH THE GROUND IN SPITE OF THIS DRY AIR. MEANWHILE...STORMS ARE ONGOING IN NORTHERN MINNESOTA...ASSOCIATED WITH THE SURFACE WARM FRONT BOUNDARY. THIS ACTIVITY WILL CONTINUE TO WORK SOUTHEASTWARD TONIGHT...AND DO NOT EXPECT THIS AREA OF PRECIPITATION TO ENTER THE PICTURE UNTIL TOMORROW MORNING...AND IT MAY NOT EVEN MAKE IT THIS FAR. FURTHER NORTH UP STREAM...CONVECTION HAS FIRED ALONG THE COLD FRONT IN SOUTHWEST ONTARIO...NEAR THE INTERSECTION OF THE COLD/WARM FRONTS. THIS CONVECTION...WILL HAVE A BIGGER IMPACT ON NORTHERN MICHIGAN. MODELS DEVELOP A LLJ LATER TONIGHT POINTING INTO CENTRAL LAKE SUPERIOR...AND THIS CONVECTION WILL FEED OFF THIS FEATURE...AND STRENGTHEN AS IT MOVES ACROSS LAKE SUPERIOR. PUSHED BACK THE POPS UNTIL AFTER MIDNIGHT AS THINGS APPEAR TO BE A BIT SLOWER ON SETTING UP. DO EXPECT THAT THE AREA OF PRECIPITATION THAT DEVELOPS WILL BE ON A WEAKENING TREND AS IT GETS INTO UPPER MICHIGAN...AS IT OUT RUNS THE FORCING WITH THE COLD FRONT AND THE LLJ BEGINS TO VEER AND WEAKEN. THUS...WILL KEEP POPS ALONG M-68 AND TO THE NORTH...BUT DOWNGRADE TO SCATTERED SHOWERS WITH AN ISOLATED THUNDERSTORM. THESE TRENDS ARE DEPICTED WELL ON THE 21Z RUC THIS EVENING. ALSO INCREASED LOW TEMPERATURES A BIT...AS DEWPOINTS HAVE BEEN RECOVERING BACK INTO THE MID TO UPPER 50S. ALSO CLOUD COVER AND INCREASING WINDS SHOULD HELP KEEP TEMPERATURES A BIT WARMER TONIGHT. KAS && .PREV DISCUSSION ISSUED AT 335 PM EDT SUN JUL 23 2006 WATER VAPOR IMAGERY SHOWING MID-UPPER LEVEL TROUGH AXIS NOW OUT ACROSS LAKE HURON WITH WEAK RIDGING OR NEUTRAL FLOW NOSING INTO THE WESTERN GREAT LAKES. PER RADAR/SATELLITE OBS... CONVECTIVE TRENDS OVER THE LAST FEW HOURS CLEARING SHOWING AFFECTS OF WARMING/CAPPING ALOFT AS CONVECTION NOW BEING SUPPRESSED ACROSS NW AND NORTH CENTRAL LOWER MICHIGAN...WHILE CONVECTION WEAKENING IN THE EAST. UPSTREAM...WARM FRONT LIFTING INTO THE UPPER MIDWEST ALONG PERIPHERY OF UPPER RIDGE...ROUGHLY ACROSS THE ARROWHEAD OF MN AND INTO WESTERN LAKE SUPERIOR. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS NOW ONGOING ALONG AND NORTH OF THIS FRONT WORKING ACROSS WESTERN LAKE SUPERIOR AND THE WESTERN U.P. TONIGHT...KAPX RADAR REVEALING A MYRIAD OF CONVECTIVE OUTFLOW BOUNDARIES ACROSS NRN LOWER MICHIGAN WHICH WILL CONTINUE TO SPARK NEW CELLS FOR A FEW MORE HOURS. BUT AS WARMING ALOFT CONTINUES CONVECTION EXPECTED TO COME TO A QUICK END FOR MOST AREAS BY EARLY EVENING. GIVEN THE CURRENT COVERAGE...WILL CARRY LIKELY POPS ACROSS PORTIONS OF NE LOWER MICHIGAN AND ISOLATED POPS OVER NORTH CENTRAL LOWER MI IN THE VERY EARLY GOING. WITH THE UPPER TROUGH AXIS NOW OFF TO THE EAST WATERSPOUT THREAT SHOULD BE ABOUT OVER WITH. SO WILL NOT INCLUDE IN THE EVENING NEARSHORE FORECASTS. THEN...UPSTREAM LOW LEVEL MOISTURE AXIS FROM IOWA INTO MN FORECAST TO SPREAD EASTWARD INTO THE WESTERN GREAT LAKES...AS 850 MB LLJ INCREASES INTO THE 40-50 KNOT RANGE. THIS SHOULD HELP TO SPREAD UPSTREAM CONVECTION IN ACROSS THE FAR NRN HALF OF THE CWA LATE THIS EVENING AND OVERNIGHT. THUS NEXT ROUND OF SHOWERS AND THUNDERSTORMS NOW UPSTREAM EXPECTED TO MAKE HEADWAY INTO THE FAR NRN PART OF THE CWA LATE THIS EVENING AND OVERNIGHT. THUS...WILL RETAIN LIKELY POPS ACROSS EASTERN UPPER MICHIGAN AFTER 03Z OR SO...AND A CHANCE OVER MOST OF NRN LOWER MICHIGAN NORTH OF M-72. ADAM EXTENDED DISCUSSION...ACTIVE PATTERN SHAPING THROUGH THE WEEK...AS THE AMPLIFIED PATTERN ACROSS NORTH AMERICA DE-AMPLIFIES...LEAVING A MORE ZONAL FLOW FOR THE MIDDLE TO END OF THE WEEK. A SERIES OF SHORTWAVES WILL SKIRT TO THE NORTH OF MICHIGAN...ONE MONDAY...ANOTHER ON WEDNESDAY...AND MAYBE ONE MORE ON FRIDAY. THESE WAVES EACH WILL SEND A COLD FRONT OVER THE GREAT LAKES REGION AND EACH FRONT WILL EVENTUALLY STALL OUT CLOSE TO US. THIS WILL LEAVE A CHANCE OF THUNDERSTORMS THROUGH THURSDAY FOR THE CWA. FOR THE MONDAY THROUGH WEDNESDAY TIME PERIOD...NAM APPEARS TO BE THE OUTLIER...AND HAVE LEANED MORE ON THE GFS/UKMET/AND ECMWF. MONDAY...WARM FRONT WILL MOVE FROM WEST TO EAST ACROSS MICHIGAN DURING THE MORNING HOURS AND SOME SHOWERS AND STORMS FROM THE OVERNIGHTS MCS MAY TRY TO BUILD BACK SW ALONG THE WESTERN FLANK OF THE 30KT LLJ WITHIN THE 850 THETAE AXIS. THEN THE COLD FRONT SETTLES SOUTH OVER THE CWA BUT THE AMOUNT OF PROGRESS SOUTHWARD IS STILL IN QUESTION. NAM WANTS TO BRING IT OVER CENTRAL MICHIGAN...WHILE THE GFS HANGS IT FARTHER NORTH OVER EASTERN UPPER. PREFER THE GFS HERE AS IT IS MORE CLOSELY ALIGNED WITH THE UKMET/ECMWF. THEREFORE...HAVE INCREASED POPS OVER EASTERN UPPER AND TIP OF THE MITT. THE AMOUNT OF INSTABILITY IS QUESTIONABLE WITH CLOUD COVER PRESENT...BUT A PARCEL OF 82/63 YIELDS A ML CAPE OF 1200 J/KG WITH NO CIN. 0-6KM SHEAR IS NOT THE GREATEST (25-30KTS)...BUT ENOUGH TO SUPPORT MULTICELLULAR ORGANIZATION WITH SMALL HAIL AND DAMAGING WINDS. THERE IS ALSO POTENTIAL FOR A GOOD SOAKING RAIN WITH K-INDEX VALUES APPROACHING 35 AND PWATS AROUND 1.5 IN. MONDAY NIGHT THROUGH TUESDAY...MODELS CONTINUE TO HAVE PROBLEMS WITH THE FINAL LOCATION OF THE STALLED OUT FRONT. NAM IS THE OUTLIER AND PLACES THE FRONT ACROSS SOUTHERN LOWER OVER THESE PERIODS (TRENDING FURTHER SOUTH THAN PAST RUNS)...WHILE THE GFS/UKMET/ECMWF KEEPS THE FRONT OVER NORTHERN LOWER. WILL BUMP UP POPS OVER NORTHERN LOWER WITH THE FRONTAL BOUNDARY IN THE VICINITY. SEVERE POTENTIAL ON TUESDAY AFTERNOON AS USUAL WILL LARGELY DEPEND ON CLOUD COVER AS THE CONVERGENCE ALONG THE FRONT WILL WEAKEN AND 0-6KM BULK SHEAR WILL BE AROUND 25KTS...BUT LOW LEVEL MOISTURE SHOULD NOT BE A PROBLEM WITH DEWPOINTS WELL INTO THE 60S. TUESDAY NIGHT INTO WEDNESDAY...MODELS CONTINUE TO SHOW THE FRONTAL BOUNDARY PARKED OUT OVER MICHIGAN AS ANOTHER SHORTWAVE DIVES OVER CENTRAL ONTARIO AND LAKE SUPERIOR. WITH THE APPROACHING WAVE...SOUTHERLY WINDS WILL STRENGTHEN AHEAD OF ITS COLD FRONT AND THE STALLED OUT BOUNDARY WILL RETURN NORTH AS A WARM FRONT. GFS DEVELOPS A 850MB SSW LLJ AROUND 40 KTS ACROSS THE CWA OVERNIGHT...NO DOUBT AIDED BY CONVECTIVE FEEDBACK. COLD FRONTAL PASSAGE WILL OCCUR DURING THE DAY ON WEDNESDAY. TOO EARLY TO GIVE SPECIFICS ON SEVERE POTENTIAL...AS THERE ARE SOME DIFFERENCES BETWEEN THE MODELS IN REGARDS TO TIMING (GFS A LITTLE QUICKER THAN THE ECMWF) WHICH WOULD AFFECTS ITS ALIGNMENT WITH PEAK HEATING. BUT WILL BUMP UP POPS OVER THESE PERIODS WITH THE FRONTAL PASSAGE. THURSDAY THROUGH SATURDAY...GFS/CANADIAN/ECMWF IN BETTER AGREEMENT... ALBEIT STILL NOT GOOD...WITH THE GENERAL UPPER AIR PATTERN HEADING INTO NEXT WEEKEND...BUT POOR RUN TO RUN CONTINUITY CONTINUES TO PREVENT ME FROM ADDING MUCH DETAIL TO THE FORECAST DURING THESE PERIODS. OVERALL PATTERN WISE...NEGATIVE PNA PATTERN IS SHAPING UP FOR NEXT WEEKEND...WITH A LARGE RIDGE BUILDING OVER THE NORTH CENTRAL PACIFIC...TROUGHING OVER THE WESTERN NOAM...AND FLAT RIDGING OVER THE CENTRAL CONUS. THIS WOULD FAVOR A WARMER AND MORE ACTIVE PATTERN FOR MICHIGAN. MODELS ARE STILL HAVE PHASING ISSUES WITH FEATURES ACROSS CENTRAL CANADA...WHICH MAKES SURFACE FEATURE TIMING PROBLEMATIC. MODELS ARE ATTEMPTING TO SHOW THE COLD FRONT WHICH WILL APPROACH THE REGION ON WEDNESDAY GETTING HUNG UP OVER THE GREAT LAKES...BEFORE AN ADDITIONAL WAVE ON FRIDAY PASSES ACROSS THE AREA. THIS MAKES SOME SENSE AS ZONAL FLOW WILL REMAIN WEAK ALOFT AND SURFACE HIGH PRESSURE OVER CENTRAL CANADA WILL ALSO REMAIN WEAK...SO NOT MUCH TO PUSH THE FRONT TO THE SOUTH. AM NOT TOO EXCITED ABOUT ADDING POPS EVERY PERIOD THROUGH FRIDAY. IT WAS JUST A DAY OR TWO AGO WE WERE TALKING ABOUT HIGH PRESSURE SETTLING IN ON THURSDAY AND FRIDAY. WILL ADD POPS TO MAINTAIN CONTINUITY AMONG SURROUNDING OFFICES...BUT OVERALL...WILL NOT MAKE MANY CHANGES UNTIL THERE IS MORE CONFIDENCE AMONGST THE MODELS. MPC && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 720 PM EDT SUN JUL 23 2006 .AVIATION... COMBINATION OF LAKE BREEZE BOUNDARIES AND REMNANT OUTFLOW FROM EARLIER CONVECTION ACROSS THE THUMB HAVE CONCENTRATED CUMULUS DEVELOPMENT- AS EVIDENCE BY GOES-E VIS AND KDTX 88D IMAGERY. HOWEVER...THE LACK OF DEEP MOISTURE ON THE UNSTABLE SIDE OF THE BOUNDARIES HAS PREVENTED SHOWERS AND STORMS TO FIRE EARLY THIS EVENING. LOCAL POOLING OF MOISTURE NEAR BOUNDARY INTERSECTIONS MAY BE ENOUGH TO GET ISOLATED CONVECTION TO DEVELOP PRIOR TO SUNSET... BUT NOT EXPECTING MUCH AT THIS TIME. HIGH CLOUDS FROM ACTIVITY OVER THE WESTERN U.P. AND NORTHERN MINNESOTA ALREADY MAKING PROGRESS INTO NORTHWESTERN SECTIONS OF THE LOWER PENINSULA. ANTI-CYCLONIC FLOW ALOFT SHOULD HELP THIN THESE CLOUDS OVER THE NEXT SEVERAL HOURS. WINDS WILL INCREASE QUICKLY MONDAY MORNING AS THE PRESSURE GRADIENT INCREASES IN ADVANCE OF THE NEXT SURFACE BOUNDARY. FURTHERMORE... VIGOROUS BOUNDARY LAYER MIXING WILL PROMOTE GUSTY CONDITIONS FROM LATE MORNING ON. NAM SOUNDINGS SUPPORT SAMPLING >30KT FLOW...WHICH SHOULD REALIZE IN THE 20-25KT NEIGHBORHOOD. LOW-LEVEL TROUGH AXIS WILL REMAIN NORTH OF THE FORECAST AREA THROUGH THE PERIOD...HOWEVER CONVECTION SHOULD DEVELOP ACROSS NORTHERN/WESTERN LOWER DURING THE AFTERNOON AND START TO MAKE INROADS INTO THE FORECAST AREA DURING THE LATE AFTERNOON AND EARLY EVENING. WILL CARRY PROB GROUP IN THE NORTHERN SITES FOR THUNDER IN THE POST 20Z TIME WINDOW. && .PREV DISCUSSION...ISSUED 404 PM EDT SUN JUL 23 2006 SHORT TERM...TONIGHT AND MONDAY 12Z RAOBS/WATER VAPOR LOOP SHOW AN AMPLIFIED PATTERN WITH A STRONG RIDGE OVER THE WESTERN CONUS AND TROUGH OVER THE GREAT LAKES. ONE SHORTWAVE EMBEDDED WITHIN THE LONGWAVE TROUGH WAS OVER LAKE HURON...WHILE OTHERS WERE UPSTREAM NEAR THE APOSTLE ISLANDS AND LAKE WINNIPEG. SURFACE ANALYSIS SHOWS BROAD HIGH PRESSURE OVER THE GREAT LAKES AND OHIO VALLEY...WITH A WEAKNESS/TROUGH OVER CENTRAL LOWER MICHIGAN. VIS SATELLITE SHOWS A RATHER MEAGER CU FIELD...EXCEPT ACROSS THE EASTERN CWA NEAR THE GREAT LAKES WHERE LAKE BREEZE CONVERGENCE HAS LED TO MORE ROBUST CLOUDS AS WELL AS PRECIP. REGIONAL RADARS SHOW CONVECTION HAS BEEN BUBBLING FROM NORTHEAST LOWER INTO THE THUMB...WITH A FEW STORMS REACHING A SIGNIFICANT INTENSITY. DECENT INSTABILITY ACROSS SOUTHEAST MICHIGAN...GREAT IN THE THUMB WITH UP TO 1500J/KG CAPE. DEWPOINT ACROSS THE INTERIOR OF THE CWA HAVE MIXED DOWN INTO THE UPPER 40S/LOW 40S...WHICH HAS SEVERELY LIMITED THE AVAILABLE ENERGY. THE ADDED MOISTURE FLUX IN THE ONSHORE FLOW FROM LAKE HURON HAS KEPT DEWPOINTS IN THE UPPER 50S/LOW 60S ACROSS THE THUMB. TAMDAR SOUNDINGS ALSO SHOW A DECENT MID-LEVEL CAP...WHICH HAS LIMITED CONVECTION DEVELOP INLAND AND GROWTH NEAR THE LAKES...WITH ONLY A FEW STORMS BEING ABLE TO PUNCH THROUGH IT. THE SHORTWAVE OVER LAKE HURON WILL TRACK INTO SOUTHEAST ONTARIO THIS EVENING...SO WOULD ONLY EXPECT THE CAP TO STRENGTHEN FURTHER ACROSS THE WESTERN CWA. OTHER THAN THE THUMB...AM ALSO A LITTLE CONCERNED ABOUT THE BETTER CU FIELD ACROSS THE SOUTHEASTERN CWA FROM PORT HURON TO MONROE. IT IS POSSIBLE WE COULD SEE SOME ADDITIONAL DEVELOPMENT ALONG THE LAKE ST CLAIR/ERIE LAKE BREEZES...HOWEVER WITH THE STRONGER CAP IN PLACE WILL ONLY MENTION A SLIGHT CHANCE TSRA IN THE SOUTHEAST...AS OPPOSED TO SCATTERED/ISOLATED ACROSS THE THUMB. THE LAKE WINNIPEG SHORTWAVE WILL SWING EASTWARD TONIGHT...PROPELLING A WARM FRONT INTO THE NORTHERN GREAT LAKES. GFS OVERDEVELOPS A CONVECTIVE COMPLEX ALONG THIS FRONT...AND CONSEQUENTLY IS MUCH SLOWER DROPPING THE BOUNDARY SOUTHWARD ACROSS THE REGION. NAM/NGM/DEVELOPMENTAL RUC SHOW A SIMILAR FASTER TIMING...WHICH IS PREFERRED. THE FRONT REMAINS WELL NORTH OF THE CWA TONIGHT...BUT THERE IS A INCREASE IN MID-LEVEL MOISTURE OVERNIGHT. SOMEWHAT CONCERNED ABOUT THE NOCTURNAL THETA-E ADVECTION PICKING UP AROUND SUNRISE. HOWEVER THE AMOUNT OF CIRRUS IN ADDITION TO THE MID CLOUDS UPSTREAM SHOULD LIMIT THE DEGREE OF CLOUD-TOP COOLING OVERNIGHT. STILL A DECENT SHOT AT THUNDERSTORMS ON MONDAY...ESPECIALLY WITH THE INCREASE IN MONDAY AND MORE FOCUS SYNOPTIC LIFT/CONVERGENCE. WITH AN INCREASING WIND FIELD AND ANOTHER DAY OF BETTER INSTABILITY...THERE IS A POTENTIAL FOR SEVERE WEATHER. MAINTAINED CHANCE WORDING...BUT TRIED TO ADD ADDITIONAL TIMING FROM NORTH TO SOUTH. TEMPS AND DEWPOINTS WILL BE A FEW DEGREES WARMER THAN TODAY. ALSO BUMPED UP WIND SPEEDS WITH THE TIGHTENING SOUTHWESTERLY GRADIENT...WHICH WILL LEAD TO LOW 80S OUT ACROSS THE THUMB AS WELL AS INLAND. LONG TERM...MONDAY NIGHT THROUGH SUNDAY EXPECT CONVECTION ON MONDAY TO CONTINUE INTO MONDAY EVENING AND DIMINISH OVERNIGHT. MODELS START TO DIFFER ON WEAR THE COLD FRONT WASHES OUT OVER LOWER MICHIGAN...WITH THE GFS...CANADIAN...EUROPEAN AND UKMET FARTHER NORTH THAN THE NAM AND LOCAL WRF. WHERE EVER THE FRONT WASHES OUT...THAT IS WHERE THE CHANCE OF THUNDERSTORMS WILL BE HIGHER ON TUESDAY AND TUESDAY NIGHT...AND FOR NOW WILL THE HIGHER CHANCE POPS FOR THE TRI CITIES AND THUMB REGION. THERE WILL BE SURFACE AND MLCAPES OF AROUND 1500 TO 2000 J/KG...WEAK SURFACE CONVERGENCE WITH THE WASHED OUT FRONT. THERE WILL BE SEVERAL WEAK IMPULSES EMBEDDED IN THE WNW FLOW OVER THE GREAT LAKES AND THE REGION WILL BE IN AREA OF DEFORMATION. THIS WILL BE ENOUGH FOR CHANCE POPS BOTH TUESDAY AND TUESDAY NIGHT...AGAIN HIGHER TO THE NORTHERN PART OF THE FORECAST AREA. SEVERE THREAT LOOKS LIMITED BY THE LACK OF A STRONG SYSTEM OR WIND FIELD. GUIDANCE TEMPS ARE IN GOOD AGREEMENT FOR THE LOWS AND DID NOT DIFFER. FOR TUESDAY HOWEVER...ETA MOS WAS MUCH LOWER GIVEN THE FARTHER SOUTH FRONTAL POSITION WITH MORE CLOUDS AND PRECIP. WENT CLOSER TO THE OLD FWC WHICH WAS A COMPROMISE WITH A LEAN TOWARD THE WARMER MAV GUIDANCE. THE NEXT MOST SOLID SHORTWAVE MOVES ACROSS THE NORTHERN LAKES ON WEDNESDAY. BOTH THE NAM AND GFS HAVE SOME ADDITIONAL CONVECTIVE ENERGY TO THE SOUTH OF THAT FOR WEDNESDAY. GIVEN THE INSTABILITY THAT WILL BE IN PLACE...WEDNESDAY COULD BE BEST CHANCE AND THE MOST WIDESPREAD COVERAGE OF THUNDERSTORMS. IN THE WAKE OF THIS SHORTWAVE...THE BOUNDARY/COLD FRONT PUSHES JUST SOUTH OF THE STATE LEAVING THE REGION IN MODEST DRY AIR AND GENERAL SUBSIDENCE. THEREFORE...WILL TAKE OUT THE CHANCE OF THUNDERSTORMS AND GO WITH A DRY FORECAST. ANOTHER SHORTWAVE AND STRONGER COLD FRONT ARE FORECAST TO MOVE INTO THE GREAT LAKES ON FRIDAY BY NEARLY ALL OF THE MODELS (EXCEPT THE LOCAL WRF...BUT 12Z RUN IS MOVING TOWARD THAT STRONGER FRIDAY COLD FRONT). WITH THE PROGGED STRENGTH AND INSTABILITY AHEAD OF THE COLD FRONT...THERE COULD BE SOME SEVERE WEATHER CHANCES ON FRIDAY. BEHIND THAT COLD FRONT...VERY DRY AND STABLE AIR IN PLACE FOR SATURDAY WITH ONLY SOME MID AND UPPER LEVEL MOISTURE FOR SUNDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BRAVENDER LONG TERM....RBP AVIATION...MANN YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 404 PM EDT SUN JUL 23 2006 .SHORT TERM...TONIGHT AND MONDAY 12Z RAOBS/WATER VAPOR LOOP SHOW AN AMPLIFIED PATTERN WITH A STRONG RIDGE OVER THE WESTERN CONUS AND TROUGH OVER THE GREAT LAKES. ONE SHORTWAVE EMBEDDED WITHIN THE LONGWAVE TROUGH WAS OVER LAKE HURON...WHILE OTHERS WERE UPSTREAM NEAR THE APOSTLE ISLANDS AND LAKE WINNIPEG. SURFACE ANALYSIS SHOWS BROAD HIGH PRESSURE OVER THE GREAT LAKES AND OHIO VALLEY...WITH A WEAKNESS/TROUGH OVER CENTRAL LOWER MICHIGAN. VIS SATELLITE SHOWS A RATHER MEAGER CU FIELD...EXCEPT ACROSS THE EASTERN CWA NEAR THE GREAT LAKES WHERE LAKE BREEZE CONVERGENCE HAS LED TO MORE ROBUST CLOUDS AS WELL AS PRECIP. REGIONAL RADARS SHOW CONVECTION HAS BEEN BUBBLING FROM NORTHEAST LOWER INTO THE THUMB...WITH A FEW STORMS REACHING A SIGNIFICANT INTENSITY. DECENT INSTABILITY ACROSS SOUTHEAST MICHIGAN...GREAT IN THE THUMB WITH UP TO 1500J/KG CAPE. DEWPOINT ACROSS THE INTERIOR OF THE CWA HAVE MIXED DOWN INTO THE UPPER 40S/LOW 40S...WHICH HAS SEVERELY LIMITED THE AVAILABLE ENERGY. THE ADDED MOISTURE FLUX IN THE ONSHORE FLOW FROM LAKE HURON HAS KEPT DEWPOINTS IN THE UPPER 50S/LOW 60S ACROSS THE THUMB. TAMDAR SOUNDINGS ALSO SHOW A DECENT MID-LEVEL CAP...WHICH HAS LIMITED CONVECTION DEVELOP INLAND AND GROWTH NEAR THE LAKES...WITH ONLY A FEW STORMS BEING ABLE TO PUNCH THROUGH IT. THE SHORTWAVE OVER LAKE HURON WILL TRACK INTO SOUTHEAST ONTARIO THIS EVENING...SO WOULD ONLY EXPECT THE CAP TO STRENGTHEN FURTHER ACROSS THE WESTERN CWA. OTHER THAN THE THUMB...AM ALSO A LITTLE CONCERNED ABOUT THE BETTER CU FIELD ACROSS THE SOUTHEASTERN CWA FROM PORT HURON TO MONROE. IT IS POSSIBLE WE COULD SEE SOME ADDITIONAL DEVELOPMENT ALONG THE LAKE ST CLAIR/ERIE LAKE BREEZES...HOWEVER WITH THE STRONGER CAP IN PLACE WILL ONLY MENTION A SLIGHT CHANCE TSRA IN THE SOUTHEAST...AS OPPOSED TO SCATTERED/ISOLATED ACROSS THE THUMB. THE LAKE WINNIPEG SHORTWAVE WILL SWING EASTWARD TONIGHT...PROPELLING A WARM FRONT INTO THE NORTHERN GREAT LAKES. GFS OVERDEVELOPS A CONVECTIVE COMPLEX ALONG THIS FRONT...AND CONSEQUENTLY IS MUCH SLOWER DROPPING THE BOUNDARY SOUTHWARD ACROSS THE REGION. NAM/NGM/DEVELOPMENTAL RUC SHOW A SIMILAR FASTER TIMING...WHICH IS PREFERRED. THE FRONT REMAINS WELL NORTH OF THE CWA TONIGHT...BUT THERE IS A INCREASE IN MID-LEVEL MOISTURE OVERNIGHT. SOMEWHAT CONCERNED ABOUT THE NOCTURNAL THETA-E ADVECTION PICKING UP AROUND SUNRISE. HOWEVER THE AMOUNT OF CIRRUS IN ADDITION TO THE MID CLOUDS UPSTREAM SHOULD LIMIT THE DEGREE OF CLOUD-TOP COOLING OVERNIGHT. STILL A DECENT SHOT AT THUNDERSTORMS ON MONDAY...ESPECIALLY WITH THE INCREASE IN MONDAY AND MORE FOCUS SYNOPTIC LIFT/CONVERGENCE. WITH AN INCREASING WIND FIELD AND ANOTHER DAY OF BETTER INSTABILITY...THERE IS A POTENTIAL FOR SEVERE WEATHER. MAINTAINED CHANCE WORDING...BUT TRIED TO ADD ADDITIONAL TIMING FROM NORTH TO SOUTH. TEMPS AND DEWPOINTS WILL BE A FEW DEGREES WARMER THAN TODAY. ALSO BUMPED UP WIND SPEEDS WITH THE TIGHTENING SOUTHWESTERLY GRADIENT...WHICH WILL LEAD TO LOW 80S OUT ACROSS THE THUMB AS WELL AS INLAND. && .LONG TERM...MONDAY NIGHT THROUGH SUNDAY EXPECT CONVECTION ON MONDAY TO CONTINUE INTO MONDAY EVENING AND DIMINISH OVERNIGHT. MODELS START TO DIFFER ON WEAR THE COLD FRONT WASHES OUT OVER LOWER MICHIGAN...WITH THE GFS...CANADIAN...EUROPEAN AND UKMET FARTHER NORTH THAN THE NAM AND LOCAL WRF. WHERE EVER THE FRONT WASHES OUT...THAT IS WHERE THE CHANCE OF THUNDERSTORMS WILL BE HIGHER ON TUESDAY AND TUESDAY NIGHT...AND FOR NOW WILL THE HIGHER CHANCE POPS FOR THE TRI CITIES AND THUMB REGION. THERE WILL BE SURFACE AND MLCAPES OF AROUND 1500 TO 2000 J/KG...WEAK SURFACE CONVERGENCE WITH THE WASHED OUT FRONT. THERE WILL BE SEVERAL WEAK IMPULSES EMBEDDED IN THE WNW FLOW OVER THE GREAT LAKES AND THE REGION WILL BE IN AREA OF DEFORMATION. THIS WILL BE ENOUGH FOR CHANCE POPS BOTH TUESDAY AND TUESDAY NIGHT...AGAIN HIGHER TO THE NORTHERN PART OF THE FORECAST AREA. SEVERE THREAT LOOKS LIMITED BY THE LACK OF A STRONG SYSTEM OR WIND FIELD. GUIDANCE TEMPS ARE IN GOOD AGREEMENT FOR THE LOWS AND DID NOT DIFFER. FOR TUESDAY HOWEVER...ETA MOS WAS MUCH LOWER GIVEN THE FARTHER SOUTH FRONTAL POSITION WITH MORE CLOUDS AND PRECIP. WENT CLOSER TO THE OLD FWC WHICH WAS A COMPROMISE WITH A LEAN TOWARD THE WARMER MAV GUIDANCE. THE NEXT MOST SOLID SHORTWAVE MOVES ACROSS THE NORTHERN LAKES ON WEDNESDAY. BOTH THE NAM AND GFS HAVE SOME ADDITIONAL CONVECTIVE ENERGY TO THE SOUTH OF THAT FOR WEDNESDAY. GIVEN THE INSTABILITY THAT WILL BE IN PLACE...WEDNESDAY COULD BE BEST CHANCE AND THE MOST WIDESPREAD COVERAGE OF THUNDERSTORMS. IN THE WAKE OF THIS SHORTWAVE...THE BOUNDARY/COLD FRONT PUSHES JUST SOUTH OF THE STATE LEAVING THE REGION IN MODEST DRY AIR AND GENERAL SUBSIDENCE. THEREFORE...WILL TAKE OUT THE CHANCE OF THUNDERSTORMS AND GO WITH A DRY FORECAST. ANOTHER SHORTWAVE AND STRONGER COLD FRONT ARE FORECAST TO MOVE INTO THE GREAT LAKES ON FRIDAY BY NEARLY ALL OF THE MODELS (EXCEPT THE LOCAL WRF...BUT 12Z RUN IS MOVING TOWARD THAT STRONGER FRIDAY COLD FRONT). WITH THE PROGGED STRENGTH AND INSTABILITY AHEAD OF THE COLD FRONT...THERE COULD BE SOME SEVERE WEATHER CHANCES ON FRIDAY. BEHIND THAT COLD FRONT...VERY DRY AND STABLE AIR IN PLACE FOR SATURDAY WITH ONLY SOME MID AND UPPER LEVEL MOISTURE FOR SUNDAY. && .PREV DISCUSSION...ISSUED 155 PM EDT SUN JUL 23 2006 AVIATION... VIS SATELLITE SHOWS A PRETTY FLOW CU FIELD ACROSS SOUTHEAST MICHIGAN...WITH THE EXCEPTION BEING ACROSS THE THUMB. CONVECTION HAS BEEN PERCOLATING IN AN AREA OF ENHANCED CONVERGENCE NEAR THE LAKE...ALTHOUGH IT HAS HAD A DIFFICULT TIME FIGHTING A MID-LEVEL CAP AROUND 20KFT OR SO DESPITE AROUND 1500J/KG CAPE. CAP APPEARS TO BE WEAKENING WITH THE APPROACH OF THE SHORTWAVE...AS RECENT STORMS HAVE BEEN MUCH TALLER/STRONGER. HOWEVER GIVEN THE LIMITED CU FIELD FARTHER SOUTHWEST...WITH THE PRESENCE OF A LOWER INVERSION ON 15Z TAMDAR SOUNDINGS AND LIMITED INSTABILITY PER SPC MESOANALYSIS...WILL LEAVE ANY THUNDER OR RAIN SHOWERS OUT OF THE TAFS. WEAK GRADIENT AND LIMITED CLOUD COVER OVERNIGHT...TO BE REPLACED BY A STRONG/GUSTY SOUTHWESTERLY FLOW ON MONDAY AND AN INCREASE IN MID-LEVEL MOISTURE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BRAVENDER LONG TERM....RBP YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 403 PM EDT SUN JUL 23 2006 .DISCUSSION... MAIN FORECAST CONCERNS ARE PRECIPITATION AND SEVERE WEATHER POTENTIAL TONIGHT THROUGH MONDAY NIGHT. CURRENT WEATHER...19Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED THE PERSISTENT WESTERN NORTH AMERICA RIDGE/EASTERN NORTH AMERICA TROUGH PATTERN. WITHIN THE TROUGH...THE MOST SIGNIFICANT FEATURE TO THE FORECAST IS A SHRTWV AND UPPER LOW OVER NE MANITOBA. SOUTH OF THIS SHRTWV...A BAND OF THICK CLOUDS EXTENDS SOUTHWARD INTO THE WEST HALF OF UPPER MICHIGAN AND NORTHERN WISCONSIN. THIS BAND IS ALSO BEING AIDED BY WARM ADVECTION AS SEEN ON 305-310K ISENTROPIC SURFACES. KDLH AND KMQT RADARS SHOW SOME LIGHT SHOWERS/SPRINKLES UNDER THIS BAND WHICH ARE IMPACTING WESTERN LAKE SUPERIOR AND WESTERN UPPER MICHIGAN. THE INCREASED CLOUD COVER HAS HELPED TO HOLD TEMPERATURES DOWN TOO WITH CURRENT READINGS ONLY IN THE 60S AND 70S. TO THE WEST OF THE BAND OF THICK CLOUDS...TEMPERATURES HAVE RISEN WELL INTO THE 80S (THANKS TO 850MB TEMPS IN THE LOW 20S C SEEN ON THE 12Z BIS AND ABR SOUNDINGS)...AND WITH DEWPOINTS ANYWHERE FROM THE MID 50S TO MID 60S AHEAD OF A SURFACE WARM FRONTAL BOUNDARY IN EASTERN NORTH DAKOTA...100MB MIXED LAYER CAPE HAS RISEN TO 500-1000 J/KG ACROSS MUCH OF MINNESOTA. THE SURFACE COLD FRONTAL BOUNDARY IS NORTH OF THE BORDER JUST AHEAD OF THE MAIN SHRTWV...ACROSS CENTRAL LAKE WINNIPEG. TONIGHT...SOME QUESTIONS EXIST REGARDING CONVECTIVE EVOLUTION. FIRST...DIURNAL SHOWERS AND THUNDERSTORMS ARE TRYING TO POP UP ACROSS NORTHEAST MN AHEAD OF A VERY WEAK SHRTWV DROPPING SE ALONG THE MN/ONTARIO BORDER. MORE OF THESE MAY FIRE OVER THE NEXT FEW HOURS AS MORE HEATING OCCURS...POSSIBLY MOVING SE INTO THE WESTERN U.P. THIS EVENING. RELATIVELY HIGH CLOUD BASES (6000 FT) AND HIGH TEMP/DEWPOINT SPREADS MAY RESULT IN SOME THREAT FOR WIND WITH THESE STORMS. SEE ARBSWOMCD ISSUED AT 1931Z FOR MORE INFORMATION. SECOND...INSTABILITY WHICH HAS GROWN ACROSS MINNESOTA HAS RESULTED IN SOME HIGH THETA-E VALUES. THIS EVENING...305K PLOTS FROM THE NAM AND GFS SUGGEST THE POSSIBILITY OF SOME ELEVATED CONVECTION DEVELOP FROM THE KEWEENAW INTO THE EASTERN CWA AS 40-45 KT WINDS RISE UP FROM NEAR THE SURFACE TO 770 MB OVER A VERY SHORT DISTANCE (EX: DULUTH TO HOUGHTON). IN FACT...GFS QPF PLOT SHOWS A BULLSEYE OF 700MB OMEGA OVER EASTERN LAKE SUPERIOR AT THE EASTERN U.P. AT 06Z. GIVEN THAT THE LOW LEVELS CONTINUE TO REMAIN DRY AND NOT TOO STABLE (THANKS TO INCREASING WINDS AHEAD OF THE WARM FRONT)...AND WET-BULB ZERO/FREEZING LEVEL HEIGHTS ARE 11000-12000 FT...SOME THREAT WOULD EXIST FOR BOTH SEVERE WIND AND HAIL. THIRDLY...MODELS ARE SUGGESTING CONVECTION TO FIRE IN SOUTHERN MANITOBA/NW ONTARIO THIS EVENING AHEAD OF THE COLD FRONT/SHRTWV...DROPPING INTO UPPER MICHIGAN AFTER MIDNIGHT. THIS TOO WOULD HAVE A THREAT FOR SOME SEVERE. SPC DAY 1 OUTLOOK CONTINUES TO SHOW A SLIGHT RISK FOR THE WEST HALF OF THE CWA...BUT IT SEEMS POSSIBLE THAT MUCH OF THE CWA COULD BE IMPACTED BY SEVERE WEATHER IF ALL THREE EVOLUTIONS COME TO PASS. WILL NEED TO MONITOR ALL THREE THROUGH THE EVENING. MONDAY...HAVE MAINTAINED SOME CHANCE OF SHOWERS AND THUNDERSTORMS IN THE MORNING FOR MUCH OF THE CWA DUE TO DYING CONVECTION. IT DOES APPEAR SOME SUNSHINE WILL BE POSSIBLE AFTER THIS CONVECTION DIMINISHES...WHICH WITH 850MB TEMPS AROUND 18C...TEMPERATURES SHOULD RISE PRETTY QUICK. MAV GUIDANCE SHOWS READINGS AT IMT AND IWD CLIMBING INTO THE MID 80S...WHICH WOULD SORT OF MATCH WHAT IS GOING ON UPSTREAM OVER SE MANITOBA BUT WITHOUT AS MUCH CLOUD COVER. HOWEVER...THIS HEATING COMBINED WITH LOW LEVEL MOISTURE (MOISTURE FROM EITHER POOLING OR FROM PREVIOUS RAINFALL) AND A WEAKENING COLD FRONT/LAKE BREEZES WILL LIKELY RESULT IN THE REDEVELOPMENT OF MORE SHOWERS AND THUNDERSTORMS. GREATEST PROBABILITY OF THIS OCCURRING APPEARS TO BE IN THE SOUTHERN U.P. SINCE AREAS SUCH AS THE KEWEENAW WILL BE UNDER THE STABLE MARINE AIR. 0-6KM SHEAR VALUES PROGGED AT 25-30KT WOULD SUGGEST MULTICELL CONVECTION...AND WITH FREEZING LEVELS AND WET BULB ZERO HEIGHTS ARE STILL PROGGED IN THE 11000-12000 FT RANGE...SOME THREAT EXISTS FOR HAIL. SPC DAY 2 OUTLOOK MAINTAINS A SLIGHT RISK ACROSS THE SOUTHERN PORTION OF THE CWA AND THIS STILL LOOKS GOOD. MONDAY NIGHT AND TUESDAY...NAM CONTINUES TO DRIVE THE COLD FRONT SOUTHWARD TO THE MANITOWOC AREA AFTER MIDNIGHT MONDAY NIGHT BEFORE RETURNING IT BACK NORTHWARD ON TUESDAY. THE GFS/UKMET/ECMWF KEEP THIS FRONT FARTHER NORTH NEAR MARINETTE AS THEY DID YESTERDAY. WILL CONTINUE TO FOLLOW THE FARTHER NORTH SOLUTION...ESPECIALLY SINCE THERE ARE INDICATIONS A SHRTWV OVER SOUTHERN ALBERTA WILL BE MOVING EASTWARD...WHICH WOULD HELP PREVENT THE FRONT FROM DROPPING TOO FAR SOUTH. BECAUSE THE FRONT REMAINS JUST SOUTH OF THE CWA...HAVE MAINTAINED A CHANCE OF SHOWERS AND THUNDERSTORMS ALONG THE WISCONSIN BORDER. THIS FRONT...WHICH ALL MODELS AGAIN PROG TO LIFT BACK NORTH...BUT ONLY OVER THE U.P. DURING THE DAY TUESDAY...WILL LIKELY SERVE AS A FOCUS FOR MORE CONVECTION ON TUESDAY. HAVE MAINTAINED CHANCE POPS FOR THE WHOLE DAY TUESDAY BECAUSE OF ANY ELEVATED CONVECTION THAT MAY TRY TO FIRE ON THE FRONT AS IT LIFTS BACK NORTHWARD TUESDAY MORNING AND FOR DIURNAL CONVECTION ON THE FRONT/LAKE BREEZES TUESDAY AFTERNOON. HARD TO SAY AT THIS POINT WHETHER ANY SEVERE ACTIVITY WILL OCCUR...BUT IT IS SOMETHING TO WATCH. TEMPERATURES BOTH PERIODS SHOULD BE ON THE WARM SIDE...ESPECIALLY WHEN 850MB TEMPS ARE EXPECTING TO REMAIN AT OR AROUND 18C. TUESDAY NIGHT AND WEDNESDAY...GFS/NAM/UKMET AND ECMWF ALL SHOW THE FLOW TURNING MORE ZONAL DURING THIS PERIOD...WITH SOME INDICATION OF A SHRTWV MOVING THROUGH THE U.P. LATE TUESDAY NIGHT WITH A WEAK COLD FRONT...THEN A WEAK PRESSURE GRADIENT PERSISTING OVER THE CWA THROUGH THE DAY ON WEDNESDAY. GIVEN THAT TUESDAY\S FRONT WILL STILL BE OVER THE AREA AND THE AFOREMENTIONED SHRTWV MAY BE COMING THROUGH...IT IS POSSIBLE FOR MORE SHOWERS AND THUNDERSTORMS. THESE MAY END BRIEFLY WEDNESDAY MORNING...BUT THEN LAKE BREEZES COMBINED WITH LOW TO MID 60S DEWPOINTS AND TEMPERATURES CLIMBING INTO 80S MAY TRY TO FIRE UP SOME MORE STORMS IN THE AFTERNOON. THEREFORE... CHANCES OF SHOWERS AND THUNDERSTORMS PERSIST THROUGH WEDNESDAY. TIMING OF THE SHOWERS AND THUNDERSTORMS SHOULD BECOME BETTER OVER THE NEXT FEW MODEL RUNS AS THE SHRTWV EXPECTED TO MOVE IN TUESDAY NIGHT MOVES INTO THE U.S.. EXTENDED (THURSDAY THROUGH SUNDAY)...OPERATIONAL MODELS AND 00Z GFS ENSEMBLES ARE FAIRLY SIMILAR TO THE WAY THEY APPEARED YESTERDAY... HOWEVER MODEL AGREEMENT IS BECOMING BETTER...LEADING TO INCREASING CONFIDENCE. SHRTWV TROUGH AND ASSOCIATED COLD FRONT...WHICH WERE PROGGED BY THE ECMWF/UKMET CAMP YESTERDAY TO MOVE THROUGH LATE WEDNESDAY...IS NOW PROGGED TO MOVE THROUGH ON THURSDAY. BECAUSE OF THIS...HAVE EXTENDED THE CHANCE POPS INTO THURSDAY AND BUMPED UP HIGHS ON THURSDAY. ECMWF INDICATES 850MB DEWPOINTS OF 14-16C AHEAD OF THIS FRONT...ALONG WITH 16-18C 850MB TEMPS AND A SHRTWV MOVING THROUGH...SO SEVERE WEATHER COULD NOT TOTALLY BE RULED OUT AS INDICATED TOO BY SPC\S DAY 4-8 OUTLOOK (TOO FAR OUT TO ASSESS PARAMETERS AT THIS TIME). HIGH PRESSURE MOVES INTO UPPER MICHIGAN BEHIND THIS FRONT ON FRI...SO DRIER AND SLIGHTLY COOLER CONDITIONS ARE EXPECTED. PATTERN THEN BEGINS TO AMPLIFY NEXT WEEKEND ACROSS NORTH AMERICA AS A TROUGH DIGS INTO AND ALONG THE COAST OF THE PACIFIC NW. THIS TROUGH WILL RESULT IN HEIGHT RISES ACROSS THE CENTRAL PLAINS INTO THE GREAT LAKES REGION...AND THEREFORE START THE INCREASE IN 850MB TEMPS. IT SHOULD BE NOTED THAT THIS UPCOMING PATTERN...PREDICTED BY ALL OF THE OPERATIONAL MODELS AND GFS ENSEMBLES...IS OPPOSITE OF CLIMATOLOGY WHICH WOULD FAVOR A RIDGE ACROSS THE NORTHERN INTERMOUNTAIN STATES AND A TROUGH OVER THE GREAT LAKES AND SE CANADA. SO NOT ONLY IS THERE AN INCREASED CONFIDENCE IN THE PATTERN...BUT IT IS LIKELY ANOTHER HEAT WAVE WILL BE DEVELOPING IN THE PLAINS WITH MCS CONVECTION MOVING AROUND THE CAP OF THE HOT AIR. SATURDAY SHOULD REMAIN DRY WITH HIGH PRESSURE OVERHEAD...BUT 850MB TEMPS ARE PROGGED TO RISE TO 16-18C BY 00Z SUN. INCREASED WARM ADVECTION SATURDAY NIGHT INTO SUNDAY WITH THE HOT AIR IN THE PLAINS MOVING TOWARDS UPPER MICHIGAN MAY RESULT IN A FEW ELEVATED STORMS. BY 18Z SUNDAY...THE 06Z GFS INDICATES 850MB TEMPS IN THE LOW 20S C...SO SUNDAY LOOKS LIKE IT COULD END UP BEING A HOT DAY AWAY FROM LAKE MICHIGAN. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 155 PM EDT SUN JUL 23 2006 .AVIATION... VIS SATELLITE SHOWS A PRETTY FLOW CU FIELD ACROSS SOUTHEAST MICHIGAN...WITH THE EXCEPTION BEING ACROSS THE THUMB. CONVECTION HAS BEEN PERCOLATING IN AN AREA OF ENHANCED CONVERGENCE NEAR THE LAKE...ALTHOUGH IT HAS HAD A DIFFICULT TIME FIGHTING A MID-LEVEL CAP AROUND 20KFT OR SO DESPITE AROUND 1500J/KG CAPE. CAP APPEARS TO BE WEAKENING WITH THE APPROACH OF THE SHORTWAVE...AS RECENT STORMS HAVE BEEN MUCH TALLER/STRONGER. HOWEVER GIVEN THE LIMITED CU FIELD FARTHER SOUTHWEST...WITH THE PRESENCE OF A LOWER INVERSION ON 15Z TAMDAR SOUNDINGS AND LIMITED INSTABILITY PER SPC MESOANALYSIS...WILL LEAVE ANY THUNDER OR RAIN SHOWERS OUT OF THE TAFS. WEAK GRADIENT AND LIMITED CLOUD COVER OVERNIGHT...TO BE REPLACED BY A STRONG/GUSTY SOUTHWESTERLY FLOW ON MONDAY AND AN INCREASE IN MID-LEVEL MOISTURE. && .PREV DISCUSSION...ISSUED 1117 AM EDT SUN JUL 23 2006 UPDATE... SHORTWAVE APPARENT IN WATER VAPOR LOOP NEAR THE STRAITS WILL DROP SOUTHEASTWARD ACROSS LAKE HURON THIS AFTERNOON. THE SURFACE FRONT FROM YESTERDAY HAS ALL BUT WASHED OUT...HOWEVER THERE REMAINS A WEAK TROUGH FROM SOUTHEAST ONTARIO AND LOWER MICHIGAN. 12Z RUC LOOKS UNDERDONE IN ITS DEPICTION OF A WEAK THETA-E RIDGE ACROSS NORTHERN LOWER/LAKE HURON...WHERE CLOUDS HAVE MAINTAINED AND A FEW SHOWERS HAVE BEEN PERCOLATING THIS MORNING. WITH WEAK CONVERGENCE/MOISTURE AT THE SURFACE AND THE UPPER SUPPORT AHEAD OF THE SHORTWAVE...WE SHOULD SEE CONVECTION INCREASE IN COVERAGE AND INTENSITY AS WE DESTABILIZE THIS AFTERNOON. KEPT SCATTERED WORDING ACROSS THE SAGINAW VALLEY AND THUMB AND INCREASED THE POPS A BIT GIVEN ACTIVITY ALREADY UPSTREAM THIS MORNING. WITH THE SHORTWAVE JUST BRUSHING THE NORTHEASTERN CWA...KEPT ISOLATED COVERAGE ACROSS THE SOUTHWEST THIS AFTERNOON. 12Z APX/TAMDAR SOUNDINGS DO SHOW A STRONGER MID-LEVEL CAP FARTHER NORTH...BUT THIS SHOULD WEAKEN/ERODE WITH THE APPROACH OF THE SHORTWAVE. SOUNDINGS ACROSS SOUTHEAST MICHIGAN SHOW A FAIR AMOUNT OF DRY AIR JUST OFF THE SURFACE. DEWPOINTS CLIMBED BACK NEAR 60F AFTER SUNRISE...BUT AS OF 15Z MANY STATIONS HAVE ALREADY MIXED BACK DOWN INTO THE MID/UPPER 50S. WITHOUT ANY REAL MOISTURE ADVECTION...EXPECT THAT INSTABILITY WILL BE LIMITED GIVEN THE AMOUNT OF DRY LOW-LEVEL AIR. MODIFIED 12Z DTX SOUNDING FOR 80/55 YIELDS 1700J/KG CAPE...WHICH IS LIKELY THE HIGH END AS DEWPOINTS WILL MORE LIKELY MIX DOWN INTO AT LEAST THE LOW 50S. SHORT TERM...TODAY AND TONIGHT THE HIGHLY AMPLIFIED PATTERN ACROSS NORTH AMERICA IS FORECAST TO TRANSITION TO A MORE ZONAL PATTERN DURING THE SHORT TERM AS THE STRONG RIDGE OVER THE WESTERN US FLATTENS AND THE LONG WAVE TROUGH OVER THE GREAT LAKES MOVES TO THE NORTHEAST. THE CURRENT WATER VAPOR LOOP SHOWS A RATHER STRONG SHORT WAVE EMBEDDED WITHIN THE MEAN TROUGH ROTATING INTO EASTERN UPPER MI. THIS WAVE IS FORECAST TO MOVE ACROSS SOUTHERN LAKE HURON EARLY THIS AFTERNOON...SPREADING SOME WEAK MID LEVEL LIFT ACROSS SOUTHEAST MI. WOULD EXPECT THAT THIS LIFT WILL ENHANCE SURFACE TROUGHING ACROSS SOUTHERN MICHIGAN...AS INDICATED BY MODEL SOLUTIONS. NAM MODEL SOUNDINGS SHOW SURFACE BASED CAPE OF 1000 TO 1500 J/KG ACROSS THE SAGINAW VALLEY AND THUMB BY AFTERNOON...WITH CAPE DECREASING TO 500 TO 800 J/KG AROUND DETROIT WHERE THERE IS LESS AVAILABLE MOISTURE BELOW 850MB. FEEL THE INSTABILITY ALONG WITH THE WEAK UPPER SUPPORT AND COLD AIR ALOFT WILL WARRANT MAINTAINING A MENTION OF SHOWERS AND THUNDERSTORMS TODAY. THE NAM AND RUC ACTUALLY SUGGEST SOME CONVECTIVE INITIATION IS POSSIBLE BY LATE MORNING ACROSS THE SAGINAW VALLEY AND THUMB. HOWEVER...A BIG LIMITING FACTOR FOR MORE WIDESPREAD CONVECTION TODAY WILL BE A CAPPING INVERSION NEAR 650MB. THE NAM IS MUCH STRONGER WITH THIS CAP COMPARED TO THE GFS. THE GFS ACTUALLY INITIALIZED MID LEVEL TEMPS BETTER THAN THE NAM...BUT STILL INDICATES A STRENGTHENING CAPPING INVERSION THROUGH THE DAY. THUS WILL KEEP POPS RELATIVELY LOW...CARRYING SCATTERED POPS IN THE SAGINAW VALLEY AND THUMB AND JUST ISOLATED TOWARD DETROIT. AS THE MID LEVEL FLOW BECOMES MORE ZONAL TONIGHT...LOW LEVEL THETA E ADVECTION WILL OCCUR ACROSS THE GREAT LAKES AS WEST-SOUTHWESTERLY LOW LEVEL FLOW STRENGTHENS. THE 00Z NCEP SUITE ARE IN STRONG AGREEMENT THAT THE BEST LOW LEVEL MOISTURE TRANSPORT WILL OCCUR ACROSS NORTHERN LOWER MI. SO WILL PLAN TO LEAVE THE FORECAST DRY WITH JUST AN INCREASE IN MID CLOUDS EXPECTED. LONG TERM...MONDAY THROUGH SATURDAY GET READY FOR AN ACTIVE WEEK WITH THE POTENTIAL OF SEVERE WEATHER AND FLOODING LOOMING FOR MOST OF THIS WEEK. OUR HIGH AMPLITUDE FLOW WILL BECOME MORE ZONAL THIS MID RANGE PERIOD AS A PERSISTENT LOW LEVEL JET AND A SERIES OF WAVES INTERACT WITH A QUASI-STATIONARY FRONT ACROSS THE HEART OF THE GREAT LAKES. SURE DETAILS AT THIS TIME ARE NEARLY IMPOSSIBLE TO FORECAST AS SUBTLE CHANGES COULD PROVIDE HUGE DIFFERENCES TO SENSIBLE WEATHER. NEVERTHELESS...NUMERICAL SUITE FOR EARLY NEXT WEEK POINT TOWARD AN IMPRESSIVE WARM THERMAL ADVECTION WITH THE NOSE OF THE INCREASING LOW LEVEL JET POINTING TOWARD THE UPPER MISSISSIPPI RIVER VALLEY THEN PROPAGATING ACROSS NORTHERN LOWER MONDAY. THIS SHOULD SET THE STAGE FOR AN MCS DEVELOPMENT AND PERHAPS ADDITIONAL ELEVATED CONVECTION ALONG THE 850MB FRONT FURTHER SOUTH THROUGH MONDAY. MEANWHILE AT THE SURFACE...WARM FRONT WILL LIFT NORTHWARD AND TIMING OF THIS ALONG WITH DAYTIME HEATING COULD PROVIDE A FOCUS FOR CONVECTION AND PERHAPS A ROUND OF SEVERE WEATHER. AT THIS TIME WE WILL RETAIN THE CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS THE NORTH IN THE MORNING THEN EXTENDING SOUTH THROUGH MONDAY AFTERNOON. TEMPERATURES AND DEWPOINTS WILL BE ON THE RISE WITH 80S AND 60S... RESPECTFULLY. THIS THEME WILL CONTINUE THROUGH THE WEEK WITH QUASI-STATIONARY BOUNDARY IN PLACE AND A SERIES OF SHORT WAVES COMING ACROSS THE ZONAL FLOW ACROSS THE NORTHERN CONUS. WITH TRAINING ECHOES AND HIGH PWATS IN PLACE...THE ADDITIONAL HAZARD WILL BE LOCALIZED FLOODING...ESPECIALLY IF WE SEE SEVERAL MCS/S TRACK ACROSS THE REGION. PERHAPS THE ONLY CONSENSUS WE ARE ABLE TO OBTAIN THIS MORNING IS A REMARKABLE TREND TOWARD SURFACE HIGHER PRESSURES BY LATE FRIDAY INTO NEXT WEEKEND. THEREFORE WE WILL EXTEND THE DRY WEATHER THROUGH THE UPCOMING WEEKEND WITH LOWER DEWPOINTS. THEN LOOKING FURTHER AHEAD...TRENDS IN THE NAO TOWARD THE POSITIVE SIDE USUALLY RESULTS IN HIGHER HEIGHTS ACROSS THE CENTER OF THE NATION INTO THE GREAT LAKES WHICH SEEMS TO BE OCCURRING IN THE GFS AND ECMWF. SO WARMER TEMPS MIGHT BE IN THE FORECAST 10 DAYS OUT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....BRAVENDER UPDATE.......BRAVENDER SHORT TERM...CONSIDINE LONG TERM....BGM YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1117 AM EDT SUN JUL 23 2006 .UPDATE... SHORTWAVE APPARENT IN WATER VAPOR LOOP NEAR THE STRAITS WILL DROP SOUTHEASTWARD ACROSS LAKE HURON THIS AFTERNOON. THE SURFACE FRONT FROM YESTERDAY HAS ALL BUT WASHED OUT...HOWEVER THERE REMAINS A WEAK TROUGH FROM SOUTHEAST ONTARIO AND LOWER MICHIGAN. 12Z RUC LOOKS UNDERDONE IN ITS DEPICTION OF A WEAK THETA-E RIDGE ACROSS NORTHERN LOWER/LAKE HURON...WHERE CLOUDS HAVE MAINTAINED AND A FEW SHOWERS HAVE BEEN PERCOLATING THIS MORNING. WITH WEAK CONVERGENCE/MOISTURE AT THE SURFACE AND THE UPPER SUPPORT AHEAD OF THE SHORTWAVE...WE SHOULD SEE CONVECTION INCREASE IN COVERAGE AND INTENSITY AS WE DESTABILIZE THIS AFTERNOON. KEPT SCATTERED WORDING ACROSS THE SAGINAW VALLEY AND THUMB AND INCREASED THE POPS A BIT GIVEN ACTIVITY ALREADY UPSTREAM THIS MORNING. WITH THE SHORTWAVE JUST BRUSHING THE NORTHEASTERN CWA...KEPT ISOLATED COVERAGE ACROSS THE SOUTHWEST THIS AFTERNOON. 12Z APX/TAMDAR SOUNDINGS DO SHOW A STRONGER MID-LEVEL CAP FARTHER NORTH...BUT THIS SHOULD WEAKEN/ERODE WITH THE APPROACH OF THE SHORTWAVE. SOUNDINGS ACROSS SOUTHEAST MICHIGAN SHOW A FAIR AMOUNT OF DRY AIR JUST OFF THE SURFACE. DEWPOINTS CLIMBED BACK NEAR 60F AFTER SUNRISE...BUT AS OF 15Z MANY STATIONS HAVE ALREADY MIXED BACK DOWN INTO THE MID/UPPER 50S. WITHOUT ANY REAL MOISTURE ADVECTION...EXPECT THAT INSTABILITY WILL BE LIMITED GIVEN THE AMOUNT OF DRY LOW-LEVEL AIR. MODIFIED 12Z DTX SOUNDING FOR 80/55 YIELDS 1700J/KG CAPE...WHICH IS LIKELY THE HIGH END AS DEWPOINTS WILL MORE LIKELY MIX DOWN INTO AT LEAST THE LOW 50S. && .PREV DISCUSSION...ISSUED 705 AM EDT SUN JUL 23 2006 AVIATION... WITH THE ONSET OF DAYTIME HEATING AND GIVEN THE COLD AIR ALOFT ASSOCIATED WITH THE UPPER LEVEL TROUGH OVER THE REGION...EXPECT A SCATTERED TO BROKEN CU FIELD TO DEVELOP BY AFTERNOON. CEILING HEIGHTS WILL BE VFR. HOWEVER...A BRIEF PERIOD OF MVFR CEILINGS WILL BE POSSIBLE THIS MORNING AROUND MBS GIVEN THE SLIGHTLY HIGHER BOUNDARY LAYER MOISTURE FROM THE SAGINAW VALLEY NORTHWARD. A SHORT WAVE TROUGH PASSING ACROSS LAKE HURON THIS MORNING AND EARLY AFTERNOON ALONG WITH INCREASING INSTABILITY THROUGHOUT THE DAY SHOULD TOUCH OFF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON. FEEL THE LIKELIHOOD OF PRECIP HITTING THE TAF SITES REMAINS TOO LOW TO PLACE IN THE TAF AT THIS TIME. SHORT TERM...TODAY AND TONIGHT THE HIGHLY AMPLIFIED PATTERN ACROSS NORTH AMERICA IS FORECAST TO TRANSITION TO A MORE ZONAL PATTERN DURING THE SHORT TERM AS THE STRONG RIDGE OVER THE WESTERN US FLATTENS AND THE LONG WAVE TROUGH OVER THE GREAT LAKES MOVES TO THE NORTHEAST. THE CURRENT WATER VAPOR LOOP SHOWS A RATHER STRONG SHORT WAVE EMBEDDED WITHIN THE MEAN TROUGH ROTATING INTO EASTERN UPPER MI. THIS WAVE IS FORECAST TO MOVE ACROSS SOUTHERN LAKE HURON EARLY THIS AFTERNOON...SPREADING SOME WEAK MID LEVEL LIFT ACROSS SOUTHEAST MI. WOULD EXPECT THAT THIS LIFT WILL ENHANCE SURFACE TROUGHING ACROSS SOUTHERN MICHIGAN...AS INDICATED BY MODEL SOLUTIONS. NAM MODEL SOUNDINGS SHOW SURFACE BASED CAPE OF 1000 TO 1500 J/KG ACROSS THE SAGINAW VALLEY AND THUMB BY AFTERNOON...WITH CAPE DECREASING TO 500 TO 800 J/KG AROUND DETROIT WHERE THERE IS LESS AVAILABLE MOISTURE BELOW 850MB. FEEL THE INSTABILITY ALONG WITH THE WEAK UPPER SUPPORT AND COLD AIR ALOFT WILL WARRANT MAINTAINING A MENTION OF SHOWERS AND THUNDERSTORMS TODAY. THE NAM AND RUC ACTUALLY SUGGEST SOME CONVECTIVE INITIATION IS POSSIBLE BY LATE MORNING ACROSS THE SAGINAW VALLEY AND THUMB. HOWEVER...A BIG LIMITING FACTOR FOR MORE WIDESPREAD CONVECTION TODAY WILL BE A CAPPING INVERSION NEAR 650MB. THE NAM IS MUCH STRONGER WITH THIS CAP COMPARED TO THE GFS. THE GFS ACTUALLY INITIALIZED MID LEVEL TEMPS BETTER THAN THE NAM...BUT STILL INDICATES A STRENGTHENING CAPPING INVERSION THROUGH THE DAY. THUS WILL KEEP POPS RELATIVELY LOW...CARRYING SCATTERED POPS IN THE SAGINAW VALLEY AND THUMB AND JUST ISOLATED TOWARD DETROIT. AS THE MID LEVEL FLOW BECOMES MORE ZONAL TONIGHT...LOW LEVEL THETA E ADVECTION WILL OCCUR ACROSS THE GREAT LAKES AS WEST-SOUTHWESTERLY LOW LEVEL FLOW STRENGTHENS. THE 00Z NCEP SUITE ARE IN STRONG AGREEMENT THAT THE BEST LOW LEVEL MOISTURE TRANSPORT WILL OCCUR ACROSS NORTHERN LOWER MI. SO WILL PLAN TO LEAVE THE FORECAST DRY WITH JUST AN INCREASE IN MID CLOUDS EXPECTED. LONG TERM...MONDAY THROUGH SATURDAY GET READY FOR AN ACTIVE WEEK WITH THE POTENTIAL OF SEVERE WEATHER AND FLOODING LOOMING FOR MOST OF THIS WEEK. OUR HIGH AMPLITUDE FLOW WILL BECOME MORE ZONAL THIS MID RANGE PERIOD AS A PERSISTENT LOW LEVEL JET AND A SERIES OF WAVES INTERACT WITH A QUASI-STATIONARY FRONT ACROSS THE HEART OF THE GREAT LAKES. SURE DETAILS AT THIS TIME ARE NEARLY IMPOSSIBLE TO FORECAST AS SUBTLE CHANGES COULD PROVIDE HUGE DIFFERENCES TO SENSIBLE WEATHER. NEVERTHELESS...NUMERICAL SUITE FOR EARLY NEXT WEEK POINT TOWARD AN IMPRESSIVE WARM THERMAL ADVECTION WITH THE NOSE OF THE INCREASING LOW LEVEL JET POINTING TOWARD THE UPPER MISSISSIPPI RIVER VALLEY THEN PROPAGATING ACROSS NORTHERN LOWER MONDAY. THIS SHOULD SET THE STAGE FOR AN MCS DEVELOPMENT AND PERHAPS ADDITIONAL ELEVATED CONVECTION ALONG THE 850MB FRONT FURTHER SOUTH THROUGH MONDAY. MEANWHILE AT THE SURFACE...WARM FRONT WILL LIFT NORTHWARD AND TIMING OF THIS ALONG WITH DAYTIME HEATING COULD PROVIDE A FOCUS FOR CONVECTION AND PERHAPS A ROUND OF SEVERE WEATHER. AT THIS TIME WE WILL RETAIN THE CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS THE NORTH IN THE MORNING THEN EXTENDING SOUTH THROUGH MONDAY AFTERNOON. TEMPERATURES AND DEWPOINTS WILL BE ON THE RISE WITH 80S AND 60S... RESPECTFULLY. THIS THEME WILL CONTINUE THROUGH THE WEEK WITH QUASI-STATIONARY BOUNDARY IN PLACE AND A SERIES OF SHORT WAVES COMING ACROSS THE ZONAL FLOW ACROSS THE NORTHERN CONUS. WITH TRAINING ECHOES AND HIGH PWATS IN PLACE...THE ADDITIONAL HAZARD WILL BE LOCALIZED FLOODING...ESPECIALLY IF WE SEE SEVERAL MCS/S TRACK ACROSS THE REGION. PERHAPS THE ONLY CONSENSUS WE ARE ABLE TO OBTAIN THIS MORNING IS A REMARKABLE TREND TOWARD SURFACE HIGHER PRESSURES BY LATE FRIDAY INTO NEXT WEEKEND. THEREFORE WE WILL EXTEND THE DRY WEATHER THROUGH THE UPCOMING WEEKEND WITH LOWER DEWPOINTS. THEN LOOKING FURTHER AHEAD...TRENDS IN THE NAO TOWARD THE POSITIVE SIDE USUALLY RESULTS IN HIGHER HEIGHTS ACROSS THE CENTER OF THE NATION INTO THE GREAT LAKES WHICH SEEMS TO BE OCCURRING IN THE GFS AND ECMWF. SO WARMER TEMPS MIGHT BE IN THE FORECAST 10 DAYS OUT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......BRAVENDER AVIATION.....CONSIDINE SHORT TERM...CONSIDINE LONG TERM....BGM YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 705 AM EDT SUN JUL 23 2006 .AVIATION... WITH THE ONSET OF DAYTIME HEATING AND GIVEN THE COLD AIR ALOFT ASSOCIATED WITH THE UPPER LEVEL TROUGH OVER THE REGION...EXPECT A SCATTERED TO BROKEN CU FIELD TO DEVELOP BY AFTERNOON. CEILING HEIGHTS WILL BE VFR. HOWEVER...A BRIEF PERIOD OF MVFR CEILINGS WILL BE POSSIBLE THIS MORNING AROUND MBS GIVEN THE SLIGHTLY HIGHER BOUNDARY LAYER MOISTURE FROM THE SAGINAW VALLEY NORTHWARD. A SHORT WAVE TROUGH PASSING ACROSS LAKE HURON THIS MORNING AND EARLY AFTERNOON ALONG WITH INCREASING INSTABILITY THROUGHOUT THE DAY SHOULD TOUCH OFF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON. FEEL THE LIKELIHOOD OF PRECIP HITTING THE TAF SITES REMAINS TOO LOW TO PLACE IN THE TAF AT THIS TIME. && .PREV DISCUSSION...ISSUED 315 AM EDT SUN JUL 23 2006 SHORT TERM...TODAY AND TONIGHT THE HIGHLY AMPLIFIED PATTERN ACROSS NORTH AMERICA IS FORECAST TO TRANSITION TO A MORE ZONAL PATTERN DURING THE SHORT TERM AS THE STRONG RIDGE OVER THE WESTERN US FLATTENS AND THE LONG WAVE TROUGH OVER THE GREAT LAKES MOVES TO THE NORTHEAST. THE CURRENT WATER VAPOR LOOP SHOWS A RATHER STRONG SHORT WAVE EMBEDDED WITHIN THE MEAN TROUGH ROTATING INTO EASTERN UPPER MI. THIS WAVE IS FORECAST TO MOVE ACROSS SOUTHERN LAKE HURON EARLY THIS AFTERNOON...SPREADING SOME WEAK MID LEVEL LIFT ACROSS SOUTHEAST MI. WOULD EXPECT THAT THIS LIFT WILL ENHANCE SURFACE TROUGHING ACROSS SOUTHERN MICHIGAN...AS INDICATED BY MODEL SOLUTIONS. NAM MODEL SOUNDINGS SHOW SURFACE BASED CAPE OF 1000 TO 1500 J/KG ACROSS THE SAGINAW VALLEY AND THUMB BY AFTERNOON...WITH CAPE DECREASING TO 500 TO 800 J/KG AROUND DETROIT WHERE THERE IS LESS AVAILABLE MOISTURE BELOW 850MB. FEEL THE INSTABILITY ALONG WITH THE WEAK UPPER SUPPORT AND COLD AIR ALOFT WILL WARRANT MAINTAINING A MENTION OF SHOWERS AND THUNDERSTORMS TODAY. THE NAM AND RUC ACTUALLY SUGGEST SOME CONVECTIVE INITIATION IS POSSIBLE BY LATE MORNING ACROSS THE SAGINAW VALLEY AND THUMB. HOWEVER...A BIG LIMITING FACTOR FOR MORE WIDESPREAD CONVECTION TODAY WILL BE A CAPPING INVERSION NEAR 650MB. THE NAM IS MUCH STRONGER WITH THIS CAP COMPARED TO THE GFS. THE GFS ACTUALLY INITIALIZED MID LEVEL TEMPS BETTER THAN THE NAM...BUT STILL INDICATES A STRENGTHENING CAPPING INVERSION THROUGH THE DAY. THUS WILL KEEP POPS RELATIVELY LOW...CARRYING SCATTERED POPS IN THE SAGINAW VALLEY AND THUMB AND JUST ISOLATED TOWARD DETROIT. AS THE MID LEVEL FLOW BECOMES MORE ZONAL TONIGHT...LOW LEVEL THETA E ADVECTION WILL OCCUR ACROSS THE GREAT LAKES AS WEST-SOUTHWESTERLY LOW LEVEL FLOW STRENGTHENS. THE 00Z NCEP SUITE ARE IN STRONG AGREEMENT THAT THE BEST LOW LEVEL MOISTURE TRANSPORT WILL OCCUR ACROSS NORTHERN LOWER MI. SO WILL PLAN TO LEAVE THE FORECAST DRY WITH JUST AN INCREASE IN MID CLOUDS EXPECTED. LONG TERM...MONDAY THROUGH SATURDAY GET READY FOR AN ACTIVE WEEK WITH THE POTENTIAL OF SEVERE WEATHER AND FLOODING LOOMING FOR MOST OF THIS WEEK. OUR HIGH AMPLITUDE FLOW WILL BECOME MORE ZONAL THIS MID RANGE PERIOD AS A PERSISTENT LOW LEVEL JET AND A SERIES OF WAVES INTERACT WITH A QUASI-STATIONARY FRONT ACROSS THE HEART OF THE GREAT LAKES. SURE DETAILS AT THIS TIME ARE NEARLY IMPOSSIBLE TO FORECAST AS SUBTLE CHANGES COULD PROVIDE HUGE DIFFERENCES TO SENSIBLE WEATHER. NEVERTHELESS...NUMERICAL SUITE FOR EARLY NEXT WEEK POINT TOWARD AN IMPRESSIVE WARM THERMAL ADVECTION WITH THE NOSE OF THE INCREASING LOW LEVEL JET POINTING TOWARD THE UPPER MISSISSIPPI RIVER VALLEY THEN PROPAGATING ACROSS NORTHERN LOWER MONDAY. THIS SHOULD SET THE STAGE FOR AN MCS DEVELOPMENT AND PERHAPS ADDITIONAL ELEVATED CONVECTION ALONG THE 850MB FRONT FURTHER SOUTH THROUGH MONDAY. MEANWHILE AT THE SURFACE...WARM FRONT WILL LIFT NORTHWARD AND TIMING OF THIS ALONG WITH DAYTIME HEATING COULD PROVIDE A FOCUS FOR CONVECTION AND PERHAPS A ROUND OF SEVERE WEATHER. AT THIS TIME WE WILL RETAIN THE CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS THE NORTH IN THE MORNING THEN EXTENDING SOUTH THROUGH MONDAY AFTERNOON. TEMPERATURES AND DEWPOINTS WILL BE ON THE RISE WITH 80S AND 60S... RESPECTFULLY. THIS THEME WILL CONTINUE THROUGH THE WEEK WITH QUASI-STATIONARY BOUNDARY IN PLACE AND A SERIES OF SHORT WAVES COMING ACROSS THE ZONAL FLOW ACROSS THE NORTHERN CONUS. WITH TRAINING ECHOES AND HIGH PWATS IN PLACE...THE ADDITIONAL HAZARD WILL BE LOCALIZED FLOODING...ESPECIALLY IF WE SEE SEVERAL MCS/S TRACK ACROSS THE REGION. PERHAPS THE ONLY CONSENSUS WE ARE ABLE TO OBTAIN THIS MORNING IS A REMARKABLE TREND TOWARD SURFACE HIGHER PRESSURES BY LATE FRIDAY INTO NEXT WEEKEND. THEREFORE WE WILL EXTEND THE DRY WEATHER THROUGH THE UPCOMING WEEKEND WITH LOWER DEWPOINTS. THEN LOOKING FURTHER AHEAD...TRENDS IN THE NAO TOWARD THE POSITIVE SIDE USUALLY RESULTS IN HIGHER HEIGHTS ACROSS THE CENTER OF THE NATION INTO THE GREAT LAKES WHICH SEEMS TO BE OCCURRING IN THE GFS AND ECMWF. SO WARMER TEMPS MIGHT BE IN THE FORECAST 10 DAYS OUT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...CONSIDINE LONG TERM....BGM AVIATION...CONSIDINE YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 343 PM CDT SUN JUL 23 2006 .DISCUSSION... MAIN FORECAST CHALLENGE IS WHERE BOUNDARY...MOVING SOUTHEAST OUT OF NORTHWEST MINNESOTA...WILL SET UP FOR MONDAY AFTERNOON AND EVENING...AND BEST AREAS FOR ASSOCIATED CONVECTION ON INTO TUESDAY. SOME STRONG CONVECTION DEVELOPING AHEAD OF FRONT IN NORTHEAST MINNESOTA...WITH DECENT SHORT WAVE DROPPING SOUTHEAST. SOME CHANCE OF DEVELOPMENT THIS EVENING OVER EAST CENTRAL MN AND WESTERN WISCONSIN AHEAD OF WEAK TROF OVER WEST CENTRAL MN. RUC IS SHOWING AN AREA OF LOW LEVEL THETA E ADVECTION AHEAD OF THE TROUGH AS IT MOVES EAST THIS EVENING. DEEP LAYER SHEAR IS AROUND 35 KNOTS OVER AREA. 20Z LAPS CIN SHOWING AROUND 80 OR HIGHER OVER PARTS OF CENTRAL MN YET...AND MAY NOT GET MUCH LOWER. NAM HAS COME AROUND MORE TO GFS POSITION OF FRONT OVER ABOUT THE CENTER OF THE CWA ON MONDAY. BOTH GFS AND NAM DO SHOW 850 TROUGH MOVING THROUGH EASTERN AREAS ON MONDAY MORNING SO IT MAY BE MORE IN LATER AFTERNOON UNTIL CONVECTION GETS GOING. BEST AREA PROBABLY OVER CENTRAL MN NEAR BETTER INSTABILITY GRADIENT. GFS SHOWING A RATHER STRONG RETURN OF 850 MB MOISTURE TRANSPORT AND ASSOCIATED INCREASE IN PRECIPITABLE WATER NEAR OR JUST NORTH OF BOUNDARY MONDAY NIGHT. WILL GO MORE WITH THIS SIGNAL FOR HIGHEST POPS DURING PERIOD...STARTING WITH CENTRAL MN AREAS...AND THEN SOUTH OVERNIGHT. IF GFS IS CORRECT...MAIN BOUNDARY MAY BE PUSHED SOUTH DURING TUESDAY...SO A LITTLE MORE DIFFICULT TO ASSESS POP LATE TUESDAY NIGHT INTO WEDNESDAY. WILL..HOWEVER..PLACE A LITTLE HIGHER POPS SOUTH CENTRAL MN..IN CASE NAM IS CORRECT WITH DEVELOPMENT IN THIS AREA. LONGER TERM...WEDNESDAY NIGHT THROUGH SUNDAY 12Z OPERATIONAL GFS NOT QUITE AS AMPLIFIED AS BEFORE...AND IN RELATIVELY DECENT AGREEMENT WITH THE 12Z ECMWF AND 12Z UKMET FOR THURSDAY. ALL MODELS BRING SHORT WAVE ACROSS THE UPPER MIDWEST... EXITING THE CWA THURSDAY NIGHT. RIDGE BUILDS IN THEREAFTER SO HAVE CONTINUED THE DRY WX FORECAST FRIDAY INTO SATURDAY. UK AND GFS SUGGEST RIDGE RIDER POSSIBLE SATURDAY NIGHT...WITH ECMWF NOT ALL THAT FAR BEHIND. HAVE MENTIONED POPS SAT NIGHT AMID WARM ADVECTION WITH ENSEMBLE TEMPS STILL NOT OVERLY WARM. WL KP SUNDAY DRY WHEN MID LEVEL TEMPS LOOK LIKE THEY WILL BECOME TOO WARM...THO HPC DOES FLAG SUNDAY FOR POSSIBLE PRECIP. SOMETHING TO WATCH. SHOULD SEE MORE 90 DEGREE MAX TEMPS NEXT WEEKEND. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPR/TDK mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1030 PM EDT SUN JUL 23 2006 .SHORT TERM /REST OF TONIGHT/... WIDESPREAD CONVECTION THIS AFTERNOON HAS DROPPED MOSTLY TO THE SOUTH OF THE RAH CWA... ALTHOUGH A FEW STORMS ARE LIKELY TO TRACK ACROSS THE FAR SOUTHERN COUNTIES OVER THE NEXT FEW HOURS. CURRENT POP FORECAST HAS THIS COVERED WELL. 00Z GSO SOUNDING SHOWS CONSIDERABLE STABILIZATION WITH GOOD MID LEVEL WARMING TAKING PLACE... ALTHOUGH THE LINGERING HIGH SURFACE DEWPOINTS OVER CENTRAL NC ARE KEEPING MUCAPES AROUND 500-1000 J/KG WITH WEAK LOW LEVEL CONVERGENCE PERSISTING THROUGH THE PIEDMONT. THE LATEST RUC AND NAM12 DROP THE 925-850 MB TROUGH SOUTHEAST INTO SOUTHEAST NC... POSSIBLY HASTENED BY THE DEPARTURE OF THE 110+ KT UPPER JET'S RIGHT ENTRANCE REGION TO OUR NORTHWEST AND THE 500 MB VORTICITY LOBE SWINGING THROUGH. THE DRY AIR PUSH NEAR THE SURFACE IS LESS PROFOUND HOWEVER... WITH A FAIRLY WEAK SURFACE HIGH EASING INTO THE AREA FROM THE NORTHWEST GIVING MINIMAL PUSH TO THE BAGGY SURFACE FRONT... AND EXPECT DEWPOINTS AND THUS TEMPERATURES TO REMAIN UP A BIT OVERNIGHT. AS A RESULT... MINIMUM TEMPS HAVE BEEN RAISED 1-3 DEGREES TONIGHT. WILL ALSO INCLUDE A MENTION OF PATCHY FOG... AS NEARLY THE ENTIRE AREA HAS SEEN RAIN AND THE MID AND HIGH CLOUDS ARE THINNING/EXITING. AREAS OF STRATUS ARE LIKELY AS WELL AS TRAJECTORIES USING THE 00Z REGIONAL SOUNDINGS INDICATE CONTINUED MOIST AIR ADVECTION BELOW 850 MB OVERNIGHT. WILL INCREASE LATE NIGHT SKY COVER. -GIH && .PREV DISCUSSION... (ISSUED 243 PM EDT SUN JUL 23 2006) SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... LATEST MSAS ANALYSIS SHOWING FOCUSED SURFACE CONVERGENCE FROM ABOUT ROCKY MOUNT/WILSON TO ROCKINGHAM...WITH THE BEST MOISTURE AND INSTABILITY ALONG AND EAST OF THAT LINE. A COUPLE OF SHOWERS OR ISOLATED THUNDERSTORMS IN PLACE IN THE FOOTHILLS...BUT VISIBLE IMAGES SHOW WHAT APPEARS TO BE INCREASING STABILITY IN A CLEARING ZONE JUST WEST OF THE TRIAD. OVERNIGHT...BOTH THE GFS AND THE NAM FORECAST INCREASING SUBSIDENCE AND DIMINISHING THETA-E AIR...WITH CENTRAL NORTH CAROLINA LARGELY IN SUBSIDENCE BY 06Z. WILL TAKE A LOOK AT THE LATEST RADAR IMAGES AND TRENDS JUST PRIOR TO GRIDDED AND DIGITAL FORECAST ISSUANCES...BUT AT THIS POINT FOR THE EVENING PLAN TO HAVE LITTLE OR NO POPS IN THE TRIAD TO SCATTERED CENTRAL AND ESPECIALLY SOUTHEAST...DIMINISHING DURING THE EVENING WITH NO SHOWERS EXPECTED OVERNIGHT. LIKE WAS THE CASE ON THE 12Z SATURDAY NAM AND GFS...THE GFS CONTINUES TO BE MORE AGGRESSIVE WITH THE NORTHWARD RETURN OF THE SURFACE TROUGH AND THE INCREASE IN MOISTURE FOR MONDAY AFTERNOON. LIKE WAS THE CASE YESTERDAY...LIKE THE NAM A LITTLE MORE GIVEN THE SHORTWAVE RIDGING ALOFT AND THE FACT THAT BOTH THE GFS AND THE NAM PROVIDE FOR 850MB RIDGING OVER MUCH OF THE AREA WELL INTO MONDAY AFTERNOON WITH THE BEST 850MB CONVERGENCE TOWARD THE SOUTH CAROLINA BORDER. BOTH MODELS FORECAST A FAIRLY TIGHT GRADIENT OF 700MB AND 850MB THETA-E SOUTH-TO-NORTH OVER CENTRAL NORTH CAROLINA...AND DESPITE THEIR MOISTURE DIFFERENCES...BOTH MODELS FOCUS THEIR BEST LIFT AND INSTABILITY IN THE SOUTH MONDAY AFTERNOON. WITHOUT MUCH UPPER DIFFLUENCE...THE 850MB RIDGE NOSING OVER NORTHERN ZONES WELL INTO MONDAY AFTERNOON...AND ZERO QPF BY THE NAM...HAVE OPTED TO CONTINUE CHANCES OF AFTERNOON SHOWERS AND THUNDERSTORMS IN THE SOUTH WITH NONE NORTH MONDAY AFTERNOON. MONDAY NIGHT...BOTH THE NAM AND THE GFS BRING AMPLE QPF OVER CENTRAL NORTH CAROLINA WITH GOOD UVV BY 06Z TUESDAY. THE NAM IS ACTUALLY STRONGER WITH ITS COMBINATION OF LOW-LEVEL CONVERGENCE AND UPPER-LEVEL DIVERGENCE...ALBEIT WEAK TO MODERATE AT BEST...WHILE BOTH MODELS INCREASE PRECIPITABLE WATER VALUES TO NEAR 2 INCHES AS THE SURFACE TROUGH MOVES NORTH. CONSIDERED LIKELY POPS ESPECIALLY SOUTHEAST ZONES MONDAY NIGHT...BUT WOULD LIKE TO SEE MORE IN THE WAY OF MID-LEVEL SUPPORT IN TERMS OF A DECENT TROUGH OR SHORTWAVE COMBINED WITH JET SUPPORT TO RAISE POPS THAT HIGH AT THIS TIME. GFS HAS VERY WEAK LOW-LEVEL CONVERGENCE DESPITE THE PRESENCE OF THE TROUGH...SO AT THIS POINT WILL MAINTAIN CHANCE POPS THOUGH IN SOME AREAS...ESPECIALLY EAST WHERE THE GREATER MOISTURE WILL BE...HIGH CHANCE POPS WILL BE FORECAST. PREFER THE GFS ON TUESDAY...BELIVING ITS MOUNTAIN INFLUENCE ON THE SURFACE PATTERN AND SHOWING MORE OF A NORTHEAST/SOUTHWEST ORIENTATION OF THE SURFACE TROUGH VERSUS A WEST/EAST ORIENTATION ON THE NAM. WITH THIS IN MIND...BETTER INSTABILITY AND LIFT FOCUS IN EASTERN ZONES AND ESSENTIALLY CHANCES FOR RAIN MONDAY NIGHT ARE MIRRORED TUESDAY. CAPE ON THE GFS IS MAXIMIZED IN THE COASTAL PLAIN TUESDAY. TUESDAY NIGHT...GOOD NVA OCCURS ON THE GFS OVER CENTRAL NORTH CAROLINA ALONG WITH A SLIGHTLY DRIER AIR MASS AND WEAK SUBSIDENCE. PLAN TO FOCUS ANY CHANCE FOR RAIN TUESDAY NIGHT IN THE EVENING. TEMPERATURES THROUGH THE PERIOD NEAR NORMAL...GENERALLY 85-90 FOR HIGHS AND MID 60S TO LOWER 70S FOR LOWS. THANKS TO AKQ FOR AFTERNOON COLLABORATION. PLAN TO HAVE GRIDDED AND WORDED FORECASTS ISSUED BY 330 PM...IF NOT BEFORE. LONG TERM /WEDNESDAY THROUGH SUNDAY/... THERE IS BETTER CONSENSUS TODAY AMONG THE MEDIUM RANGE MODELS IN MAINTAINING A WEAK MID AND UPPER LEVEL TROUGH OVER THE EASTERN CONUS THROUGH THE PERIOD. DOWNSTAIRS...WESTWARD EXTENSION OF BERMUDA HIGH WILL PROVIDE WARM AND HUMID CONDITIONS THROUGH THE BOUNDARY LAYER. DIURNALLY DRIVEN CONVECTION POSSIBLE EACH DAY...ENHANCED BY WEAK MID LEVEL IMPULSES THAT ARE BEYOND CURRENT MODEL RESOLUTION. SEABREEZE INTERACTION IS ALSO EXPECTED TO BE A FACTOR WITH PROLONGED PERIOD OF S/SW FLOW. SEASONABLE TEMPERATURES CONTINUE THROUGH THE PERIOD. HIGHS 88 TO 93. LOWS 68 TO 73. AVIATION... SHOWERS AND THUNDERSTORMS WILL INCREASE AND INTENSIFY SOME EAST AS THEY MOVE FROM WEST TO EAST ACROSS THE FORECAST AREA THROUGH THE EVENING HOURS. UPPER LEVEL TROUGH TRANSVERSES THE AREA AND WEAKENING SURFACE FRONT CURRENTLY BETWEEN THE TRIAD AND TRIANGLE CRAWLS SLOWLY SOUTHEAST. FRONTAL BOUNDARY WILL MORE THAN LIKELY STALL OUT ALONG THE SANDHILLS OR COASTAL PLAIN OVERNIGHT BEFORE FINALLY SHIFTING JUST SOUTH OF THE AREA MONDAY MORNING. SATELLITE IMAGERY INDICATING DRIER AIR ALOFT BEGINNING TO ADVECT INTO WESTERN PORTIONS OF THE STATE...SCATTERING OUT CLOUD COVER. WILL CONTINUE THIS TREND THROUGH THE EVENING ACROSS THE NORTH INCLUDING RDU AND RWI TAF SITES. MAYBE SOME MINOR MVFR FOG AROUND DAYBREAK...OTHERWISE NSW. ACROSS THE SOUTH...SHORT TERM MODELS INDICATE MOISTURE WILL PERSIST ALONG STALLED BOUNDARY. MVFR CEILINGS AND FOG ARE POSSIBLE ALONG AND EAST THE BOUNDARY OVERNIGHT...LIFTING BY MID MORNING. SMALL CHANCE OF SHOWERS ACROSS THE SOUTH NEAR LINGERING BOUNDARY...OTHERWISE SCATTERED TO BKN STRATOCU BY EARLY AFTERNOON WITH A LIGHT ESE BREEZE. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HARTFIELD nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE RALEIGH NC 1055 AM EDT SUN JUL 23 2006 .SHORT TERM /REST OF TODAY AND TONIGHT/... MSAS SHOWS AXIS OF LOW-LEVEL MOISTURE AND CONVERGENCE TAKING SHAPE ACROSS THE SOUTHERN PIEDMONT...ACROSS THE SANDHILLS INTO THE COASTAL PLAIN...WITH LIFTED INDICES AROUND -3C. THIS COINCIDES WITH THE RUC AND NAM FORECAST OF HIGHEST CONVERGENCE AND THETA-E AT 850MB AND 700MB...ALONG WITH CAPE OVER 2000J/KG AND LOWER LIFTED INDICES...BY 21Z THIS AFTERNOON. HIGH-DETAIL LOOK AT RUC AND NAM SURFACE FORECAST FOR LATE THIS AFTERNOON SUGGESTS A SURFACE TROUGH WILL FOCUS IN SOUTHERN AND EASTERN ZONES...AND WITH BETTER MOISTURE AND THE RIGHT ENTRANCE REGION OF A MID-LEVEL 45KT JET JUST TO OUR NORTH...PRECIPITATION CHANCES LOOK BEST IN SOUTH AND SOUTHEAST ZONES THIS AFTERNOON. RUC MODEL SOUNDING TOWARD THE TRIAD STILL HAS SOME INSTABILITY LATE THIS AFTERNOON ALTHOUGH CAPPING IS FORECAST TO TAKE PLACE THERE BY 00Z OR SO. SEVERE WEATHER POTENTIAL APPEARS TO BE HIGHEST IN CENTRAL NORTH CAROLINA ALONG AND SOUTH OF A LINE FROM ABOUT ALBEMARLE TO WILSON...WHERE BETTER SUPPORT WILL LIE ALONG WITH BETTER CHANCES FOR INSOLATION NEAR WHAT MAY SET UP AS A DIFFERENTIAL HEATING BOUNDARY DUE TO PERSISTENT CLOUDS. RUC RELATIVE HUMIDITY FORECASTS AT VARIOUS LEVELS DO NOT SEEM OPTIMISTIC FOR A LOT OF SUN...ALTHOUGH HEATING SHOULD BE MAXIMIZED SOUTHEAST. HAVE OPTED TO LEAVE TEMPERATURES ABOUT AS IS SOUTHERN ZONES...ACTUALLY LOWERING THEM A DEGREE OR TWO TOWARD THE NORTHWEST. IF THE OVERNIGHT WRF IS CORRECT...CHANCES FOR SHOWERS AND THUNDERSTORMS SHOULD DIMINISH RAPIDLY TOWARD THE COAST EARLY THIS EVENING...WITH SMALL CHANCES LINGERING POSSIBLY A LITTLE LONGER IN THE FAR SOUTHERNMOST ZONES. GRIDDED AND WORDED FORECASTS ALREADY ISSUED. THANKS TO RNK AND AKQ FOR MORNING COLLABORATION. && .PREV DISCUSSION... (ISSUED 638 AM EDT SUN JUL 23 2006) SHORT TERM /REST OF TODAY/... QUICK UPDATE TO SIGNIFICANTLY LOWER POPS AND REMOVE MENTION OF THUNDER THIS MORNING ACROSS THE AREA AS PRECIP HAS WEAKENED AND DISSIPATED OR MOVED NORTH OF THE CWA. FORECAST FOR THE REMAINDER OF THE DAY APPEARS ON TRACK WITH SFC FRONT AND POTENT UPPER TROF POISED TO AFFECT THE AREA THIS AFTERNOON. -VINCENT PREV DISCUSSION... (ISSUED 245 AM EDT SUN JUL 23 2006) SHORT TERM /TODAY THROUGH MONDAY NIGHT/... MANUAL SFC ANALYSIS EARLY...EARLY THIS MORNING SHOWS AN UNUSUAL JULY COLD FRONT ALONG THE APPALACHIAN MOUNTAINS STRETCHING FROM ALABAMA NORTHEAST INTO NJ/NY. A TROF ASSOC/W A SFC LOW OVER NEW ENGLAND STRETCHED SOUTH INTO CENTRAL VA AND THE NW PIEDMONT OF NC. DIFFUSE 5-8F TEMP/DEWPOINT DROPS WERE OBSERVED BEHIND THE FRONT WEST OF THE MOUNTAINS. AN AREA OF SFC CONVERGENCE ASSOC/W A WIND SHIFT WAS LOCATED AHEAD OF THE FRONT ALONG THE NC/SC/GA COASTAL PLAIN. A 100 MILE WIDE AREA OF SHOWERS AND ISOLATED THUNDERSTORMS WAS LOCATED ALONG AND EAST OF THE SFC FRONT...INDICATING FORWARD SLOPING ASCENT. MOST IMPRESSIVE THIS MORNING IS THE STRONG UPPER LEVEL TROF AFFECTING THE EASTERN HALF OF THE US! 250 MB WINDS ARE AROUND 100-110 KTS ALONG THE US/CA BORDER IN THE NORTHEAST AND UPPER MIDWEST PER 00Z RAOBS...WITH MAX WINDS OF 50-70 KTS ACROSS THE MID-ATLANTIC. WINDS WILL INCREASE ALOFT OVER THE AREA TODAY AS THE UPPER TROF PROGRESSES TOWARDS THE EAST DURING THE DAY. THE 250 MB TROF WILL COME CLOSE TO CENTRAL NC THIS AFTERNOON...PROGGED TO BE JUST NORTH OF THE AREA IN SOUTHERN AND CENTRAL VA. THE COMBINATION OF STRONG CYCLONIC CURVATURE AND A JET ENTRANCE WILL YIELD COMPELLING UPPER LEVEL SUPPORT IN N/NE NC NORTHWARDS INTO VA. MODEL THERMODYNAMIC PROFILES SUPPORT SHRA/TSRA ACTIVITY INTO THIS AFTERNOON AS THE SFC FRONT OVER THE MOUNTAINS SLOWLY CROSSES INTO CENTRAL/EASTERN NC. WITH DRIER SFC DEWPOINTS (MID 60S) AND A DECENT AMOUNT OF DRY AIR ALOFT ENTERING THE AREA FROM WEST TO EAST BEHIND THE UPPER TROF...CHANCES FOR PRECIP WILL BEGIN TO DIMINISH IN THE WEST AS THE EVENING PROGRESSES...SPREADING EAST TONIGHT AS THE SFC FRONT MAKES IT INTO EASTERN NC AND THE UPPER LEVEL TROF BEGINS TO LIFT INTO THE NORTHEAST. AS FAR AS THE SEVERE THREAT IS CONCERNED THIS AFTERNOON...THERE IS A SLIGHT RISK FOR THE EASTERN PORTION OF THE CWA. AREA OF CONCERN FOR SEVERE CONVECTION TODAY WILL BE IN THE VICINITY OF THE SFC FRONT ALONG AND EAST OF A LINE FROM SOUTHERN PINES NORTH TO RALEIGH...NORTH TO ROXBORO. WITHIN THIS AREA...THE BEST CHANCE APPEARS TO BE IN NORTHEAST PORTIONS OF THE CWA...INCLUDING ROCKY MOUNT...ROANOKE RAPIDS...LOUISBURG AND WARRENTON WHERE THE SFC FRONT AND UPPER LEVEL DYNAMICS ARE MOST LIKELY TO COMBINE FORCES. SOUTHEAST PORTIONS WILL HAVE STRONGER INSTABILITY...BUT WILL BE FURTHER REMOVED FROM THE BEST DYNAMICS. PRIMARY SEVERE THREAT WILL BE DAMAGING DOWNBURST WINDS. ON MONDAY THE GFS DEPICTS THE SFC FRONT HANGING UP ALONG THE CAROLINA COAST...THEN MOVING SLOWLY BACK TO THE NORTH AND MEANDERING OVER THE AREA ON TUESDAY AND WEDNESDAY. THE NAM SHOWS THE SFC FRONT HANGING UP FURTHER TO THE SOUTH...STAYING SOUTH OF THE AREA THROUGH WEDNESDAY. AT THIS POINT...WILL GO WITH A COMPROMISE BETWEEN THESE TWO SOLUTIONS AND CONTINUE ENHANCED DIURNAL POPS (30-40) ACROSS THE AREA ON MON-TUE-WED...WITH BEST CHANCES TO THE SOUTH. NEAR AVERAGE HIGH AND LOW TEMPS ARE EXPECTED DURING THE NEXT FEW DAYS. LONG TERM /TUESDAY THROUGH SATURDAY/... CENTRAL NC REMAINS ON THE WESTERN PERIPHERY OF THE BERMUDA HIGH DURING THIS TIME FRAME WITH LOW AMPLITUDE MERIDIONAL FLOW AND SEVERAL UPPER LEVEL IMPULSES PROGGED TO CROSS THE AREA. MODEL SOUNDINGS SHOW THERMODYNAMIC PROFILES BECOMING INCREASINGLY MORE MOIST IN THE EXTENDED. THESE FACTORS SUGGEST A CHANCE OF DIURNAL CONVECTION EACH DAY...BECOMING MORE LIKELY AND POSSIBLY EXTENDING INTO THE OVERNIGHT HOURS AS MODULATED BY UPPER LEVEL IMPULSES CROSSING THE AREA. NEAR AVERAGE HIGH/LOW TEMPS EXPECTED AT THIS POINT. AVIATION... AN UNUSUALLY LARGE AMPLITUDE TROUGH FOR JULY PUSHES A COLD FRONT SLOWLY ACROSS WESTERN SECTIONS EARLY THIS MORNING AND THROUGH EASTERN SECTIONS BY MID AFTERNOON. A BROAD BAND OF MVFR AND OCNL IFR CONDITIONS CAN BE EXPECTED IN NMRS SHWRS AND ISOLTD TSTMS WITH AN AHEAD OF THE FRONT. LOW LEVEL FLOW SHOULD TURN MORE NORTHERLY BEHIND THE FRONT AND BRING DRIER AIR WITH VFR CONDITIONS LATER THIS EVENING. DIMINISHING SURFACE WIND AND CLEARING SKIES WILL PROMPT AREAS OF FOG LATE TONIGHT. -RFG && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJF nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 830 PM CDT SUN JUL 23 2006 FORECAST CHALLENGE FOR UPDATE CONCERNS PCPN CHANCES AND AREAL COVERAGE. NE-SW ORIENTED PREFRONTAL TROUGH HAS SHIFTED EAST OF FA WITH COOL FRONT ORIENTED E-W ALONG INTERNATIONAL BORDER. MAIN SHORTWAVE ASSISTING IN STRONG/DEEP CONVECTION OVER MN ARROWHEAD AREA SHIFTING SE WITH SECONDARY IMPULSE WORKING ON WEAK CONVECTION IN SLIGHTLY UNSTABLE AIRMASS AHEAD OF COOL FRONT ALONG INTERNATIONAL BORDER. CAP APPEARS TO HOLDING AS CONVECTION HAS WEAKENED CONSIDERABLY AND NOW NEARLY NON-EXISTENT. CU FIELD ALSO WEAK MAINLY CONFINED ALONG COLD FRONT ENTERING NORTHERN FA. ANOTHER SHORTWAVE AND ASSOCIATED WEAKENING CONVECTION OVER FAR NW ND PROPAGATING SE. WITH LOSS OF SURFACE HEATING AND NIL LOW LEVEL JET LOSING CONFIDENCE ON ANY ADDITIONAL CONVECTION FOR THE FA OVERNIGHT. RUC WHICH IS HANDLING ABOVE FEATURES PRETTY WELL ALSO NOT SHOWING ANY ACTION OVERNIGHT. TO BE SAFE WILL MAINTAIN ISOLD MENTION OVER NORTHERN THIRD DROPPING POPS ELSEWHERE. COLUMN COOLS A LITTLE OVERNIGHT HOWEVER WARMER DAY SHOULD OFFSET RESULTING IN TEMPS SIMILAR TO THIS MORNING. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OHIO 1027 AM EDT SUN JUL 23 2006 .SHORT TERM UPDATE (THIS AFTERNOON)... AREA OF SHOWERS MOVING OFF THE LAKE THIS MORNING INTO NE OH...THEREFORE MAINTAINED CHC POPS ACROSS NE OH/NW PA ZONES INTO THIS AFTN. MOST SITES SHOWING VISBYS UP ABOVE 6SM AT THIS TIME SO REMOVED MENTION OF MORNING FOG. CONCERN THROUGH AFTN WILL BE THE CHC OF SHRA OR TSTMS AS UPPER TROUGH SWINGS THROUGH AREA. && .AVIATION(12Z-12Z)... SOME STRATUS AND FOG...IFR OR LESS HAS DEVELOPED...THESE CONDITIONS SHOULD QUICKLY IMPROVE AFTER 13Z. THEY DEVELOPED ESPECIALLY IN THE EASTERN PORTION OF THE FORECAST AREA BECAUSE OF ALL THE RAIN THAT FELL SATURDAY AND THEN THE SKIES CLEARED. THE NEXT QUESTION IS WILL THUNDERSTORMS DEVELOP THIS AFTERNOON. WRF/NAM...NGM...GFS AND RUC ALL INDICATE THAT WIDELY SCATTERED LOW TOP CONVECTION WILL DEVELOP BECAUSE OF THE STEEP LAPSE RATES AND MODERATE INSTABILITY. CAPE NOT EXCESSIVELY HIGH. CONVECTION TEMPERATURES ARE IN THE MID 70S...THIS SHOULD BE REACH BY NOON AND A SHORT WAVE ACCORDING TO THE RUC AND WRF/NAM SHOULD CROSS THE FORECAST AREA THIS AFTERNOON. CONVECTION COULD START QUICKLY. ANY SEVERE WEATHER SHOULD BE ISOLATED BECAUSE OF THE LIMITED MOISTURE. THE ONLY FLY IN THE OINTMENT IS THAT HIGH PRESSURE IS BUILDING IN AT THE SURFACE THIS AM. HOWEVER...THE COLD AIR ALOFT AND SHORT WAVE SHOULD OVERCOME THIS. CLEARING SKIES TONIGHT. SOME MOISTURE WILL STILL BE AROUND FOR AREAS OF MVFR FOG. && .SHORT TERM(TODAY THROUGH MONDAY NIGHT)... SURFACE HIGH BUILDING SE TODAY BUT TROUGH ALOFT MOVG EAST AS WELL ACROSS E GRTLKS. COLDEST AIR ALOFT WILL BE OVER E GRTLKS FOR MUCH OF THE DAY. MODEL SOUNDINGS DO NOT SHOW A LOT OF CAPE (FOR MID SUMMER) BUT WET BULB ZERO PROGGED TO BE LOW...AROUND 9K WITH A CONVECTIVE TEMPS IN THE MID AND UPPER 70S AND THERE WAS QUITE A BIT OF ACTIVITY OVER NORTH AND CENTRAL LOWER MI WEST TO WISCONSIN ON SATURDAY. BELIEVE THIS ACTIVITY WILL DEVELOP TODAY ACROSS NORTHERN OHIO AND NORTHWEST PENNSYLVANIA BUT COVERAGE WILL STILL BE IN THE 20-40% RANGE AND WILL USE "CHANCE" IN FCST. COULD BE A BIT OF A LAKE SHADOW ALONG IMMEDIATE LAKESHORE WITH NNW BOUNDARY LAYER FLOW. ONE WOULD THINK THAT THERE SHOULD BE A BETTER CHANCE FOR POP UP STORMS OVER NE OH/NW PA WHERE COLDEST AIR ALOFT WILL BE PRESENT AND I THINK THAT WILL BE THE CASE BUT CAPE WILL BE A BIT HIGHER OVER NW OHIO WHERE TEMPS WILL SNEAK INTO LOWER 80S SO WILL PROB BE A FEW STORMS OVER NW OHIO AS WELL. WITH LOW FREEZING LEVEL AND SFC DELTA THETA-E -15 TO -20 WILL HAVE TO WATCH FOR ISOLATED HAIL/GUSTY WINDS. ANY ACTIVITY WILL DISSIPATE THIS EVENING. TROUGH ALOFT VERY PROGRESSIVE ALTHOUGH SURFACE HIGH IS BROAD AND WILL LINGER ACROSS OHIO VALLEY MONDAY. SW RETURN FLOW WILL DEVELOP MONDAY AND TEMPS SHOULD REBOUND SEVERAL CATEGORIES ESPECIALLY NW OHIO ALTHOUGH DEWPOINTS SHOULD REMAIN IN CHECK DURING THE DAY MONDAY (LOWER 60S). WARM FRONT WILL BE PASSING NORTH OF AREA BY MONDAY NIGHT AND TSTORMS SHOULD INITIALLY STAY NORTH OF THE AREA. BASED ON UPSTREAM TEMPS AND BOUNDARY LAYER THERMAL FIELDS THE GFS TEMP GUIDANCE MAY BE A DEGREE OR TWO TOO WARM TODAY MOST SITES AND PERHAPS AGAIN TOMORROW OVER EXTREME NE OH/NW PA OTHERWISE GFS GUIDANCE TEMPS LOOK GOOD AND SIMILAR TOO OTHER TEMP GUIDANCE. && .LONG TERM(TUESDAY THROUGH SATURDAY)... DID NOT CHANGE LONG TERM GRAPHICS/FCST BEYOND TUESDAY BUT DID UP THE CHANCE FOR SHOWERS/STORMS ON TUESDAY TO 30 PERCENT MOST AREAS TO GET IT MENTIONED IN FCST. SEEMS LIKELY THAT TSTORMS WILL OCCUR ACROSS NORTHERN GREAT LAKES AND SW ONTARIO AND OUTFLOW BOUNDARIES COULD GET DRAWN SOUTH FAR ENOUGH TO DEVELOP NEW STORMS SOUTH OF LAKE ERIE ON TUESDAY...AT LEAST A SMALL CHANCE...AS TEMPS AND DEWPOINTS WILL BE COMING UP AND INSTABILITY WILL INCREASE. BEST CHANCE FOR STORMS WILL PROBABLY OCCUR LATER IN THE WEEK AS TRUE COLD FRONT EVENTUALLY DROPS SOUTHEAST ACROSS GREAT LAKES. YESTERDAYS LONG TERM DISCUSSION FOLLOWS... ALL 3 MODELS IN AGREEMENT WITH TREND OF UPPER LEVEL PATTERN. AMPLIFIED RIDGE OVER WRN US AND DEEP TROUGH OVER ERN US BECOMES MORE ZONAL BY MID WEEK WITH A SERIES OF DEEP LOWS ROTATING ACROSS EXTREME NRN CANADA. BY THE END OF THE WORK WEEK ANOTHER IMPULSE DROPS OUT OF CANADA HELPING DIG ANOTHER TROUGH (THOUGH NOT AS DEEP) OVER ERN US. BASICALLY FROM THURSDAY ON SERIES OF WEAK SHORT WAVES MOVE ACROSS THE AREA BRINING CHC POPS...WITH TEMPERATURES FAIRLY CLOSE TO NORMALS. && .CLE WATCHES/WARNINGS/ADVISORIES... .OH...NONE. .PA...NONE. && $$ SHORT TERM UPDATE...ABE SHORT TERM...KOSARIK LONG TERM...KOSARIK/DJB AVIATION...KIELTYKA oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OHIO 727 AM EDT SUN JUL 23 2006 .AVIATION(12Z-12Z)... SOME STRATUS AND FOG...IFR OR LESS HAS DEVELOPED...THESE CONDITIONS SHOULD QUICKLY IMPROVE AFTER 13Z. THEY DEVELOPED ESPECIALLY IN THE EASTERN PORTION OF THE FORECAST AREA BECAUSE OF ALL THE RAIN THAT FELL SATURDAY AND THEN THE SKIES CLEARED. THE NEXT QUESTION IS WILL THUNDERSTORMS DEVELOP THIS AFTERNOON. WRF/NAM...NGM...GFS AND RUC ALL INDICATE THAT WIDELY SCATTERED LOW TOP CONVECTION WILL DEVELOP BECAUSE OF THE STEEP LAPSE RATES AND MODERATE INSTABILITY. CAPE NOT EXCESSIVELY HIGH. CONVECTION TEMPERATURES ARE IN THE MID 70S...THIS SHOULD BE REACH BY NOON AND A SHORT WAVE ACCORDING TO THE RUC AND WRF/NAM SHOULD CROSS THE FORECAST AREA THIS AFTERNOON. CONVECTION COULD START QUICKLY. ANY SEVERE WEATHER SHOULD BE ISOLATED BECAUSE OF THE LIMITED MOISTURE. THE ONLY FLY IN THE OINTMENT IS THAT HIGH PRESSURE IS BUILDING IN AT THE SURFACE THIS AM. HOWEVER...THE COLD AIR ALOFT AND SHORT WAVE SHOULD OVERCOME THIS. CLEARING SKIES TONIGHT. SOME MOISTURE WILL STILL BE AROUND FOR AREAS OF MVFR FOG. && .SHORT TERM(TODAY THROUGH MONDAY NIGHT)... SURFACE HIGH BUILDING SE TODAY BUT TROUGH ALOFT MOVG EAST AS WELL ACROSS E GRTLKS. COLDEST AIR ALOFT WILL BE OVER E GRTLKS FOR MUCH OF THE DAY. MODEL SOUNDINGS DO NOT SHOW A LOT OF CAPE (FOR MID SUMMER) BUT WET BULB ZERO PROGGED TO BE LOW...AROUND 9K WITH A CONVECTIVE TEMPS IN THE MID AND UPPER 70S AND THERE WAS QUITE A BIT OF ACTIVITY OVER NORTH AND CENTRAL LOWER MI WEST TO WISCONSIN ON SATURDAY. BELIEVE THIS ACTIVITY WILL DEVELOP TODAY ACROSS NORTHERN OHIO AND NORTHWEST PENNSYLVANIA BUT COVERAGE WILL STILL BE IN THE 20-40% RANGE AND WILL USE "CHANCE" IN FCST. COULD BE A BIT OF A LAKE SHADOW ALONG IMMEDIATE LAKESHORE WITH NNW BOUNDARY LAYER FLOW. ONE WOULD THINK THAT THERE SHOULD BE A BETTER CHANCE FOR POP UP STORMS OVER NE OH/NW PA WHERE COLDEST AIR ALOFT WILL BE PRESENT AND I THINK THAT WILL BE THE CASE BUT CAPE WILL BE A BIT HIGHER OVER NW OHIO WHERE TEMPS WILL SNEAK INTO LOWER 80S SO WILL PROB BE A FEW STORMS OVER NW OHIO AS WELL. WITH LOW FREEZING LEVEL AND SFC DELTA THETA-E -15 TO -20 WILL HAVE TO WATCH FOR ISOLATED HAIL/GUSTY WINDS. ANY ACTIVITY WILL DISSIPATE THIS EVENING. TROUGH ALOFT VERY PROGRESSIVE ALTHOUGH SURFACE HIGH IS BROAD AND WILL LINGER ACROSS OHIO VALLEY MONDAY. SW RETURN FLOW WILL DEVELOP MONDAY AND TEMPS SHOULD REBOUND SEVERAL CATEGORIES ESPECIALLY NW OHIO ALTHOUGH DEWPOINTS SHOULD REMAIN IN CHECK DURING THE DAY MONDAY (LOWER 60S). WARM FRONT WILL BE PASSING NORTH OF AREA BY MONDAY NIGHT AND TSTORMS SHOULD INITIALLY STAY NORTH OF THE AREA. BASED ON UPSTREAM TEMPS AND BOUNDARY LAYER THERMAL FIELDS THE GFS TEMP GUIDANCE MAY BE A DEGREE OR TWO TOO WARM TODAY MOST SITES AND PERHAPS AGAIN TOMORROW OVER EXTREME NE OH/NW PA OTHERWISE GFS GUIDANCE TEMPS LOOK GOOD AND SIMILAR TOO OTHER TEMP GUIDANCE. && .LONG TERM(TUESDAY THROUGH SATURDAY)... DID NOT CHANGE LONG TERM GRAPHICS/FCST BEYOND TUESDAY BUT DID UP THE CHANCE FOR SHOWERS/STORMS ON TUESDAY TO 30 PERCENT MOST AREAS TO GET IT MENTIONED IN FCST. SEEMS LIKELY THAT TSTORMS WILL OCCUR ACROSS NORTHERN GREAT LAKES AND SW ONTARIO AND OUTFLOW BOUNDARIES COULD GET DRAWN SOUTH FAR ENOUGH TO DEVELOP NEW STORMS SOUTH OF LAKE ERIE ON TUESDAY...AT LEAST A SMALL CHANCE...AS TEMPS AND DEWPOINTS WILL BE COMING UP AND INSTABILITY WILL INCREASE. BEST CHANCE FOR STORMS WILL PROBABLY OCCUR LATER IN THE WEEK AS TRUE COLD FRONT EVENTUALLY DROPS SOUTHEAST ACROSS GREAT LAKES. YESTERDAYS LONG TERM DISCUSSION FOLLOWS... ALL 3 MODELS IN AGREEMENT WITH TREND OF UPPER LEVEL PATTERN. AMPLIFIED RIDGE OVER WRN US AND DEEP TROUGH OVER ERN US BECOMES MORE ZONAL BY MID WEEK WITH A SERIES OF DEEP LOWS ROTATING ACROSS EXTREME NRN CANADA. BY THE END OF THE WORK WEEK ANOTHER IMPULSE DROPS OUT OF CANADA HELPING DIG ANOTHER TROUGH (THOUGH NOT AS DEEP) OVER ERN US. BASICALLY FROM THURSDAY ON SERIES OF WEAK SHORT WAVES MOVE ACROSS THE AREA BRINING CHC POPS...WITH TEMPERATURES FAIRLY CLOSE TO NORMALS. && .CLE WATCHES/WARNINGS/ADVISORIES... .OH...NONE. .PA...NONE. && $$ SHORT TERM...KOSARIK LONG TERM...KOSARIK/DJB AVIATION...KIELTYKA oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 213 PM EDT SUN JUL 23 2006 .SHORT TERM (TONIGHT THROUGH MON)... BASED ON RECENT RADAR DATA AND RUC MODEL, A COLD TROUGH ALOFT MOVING ACROSS THE EASTERN GREAT LAKES, EXPECT ISOLATED SHOWERS TO MOVE EWD ACROSS NW PENNSYLVANIA UNTIL SUNSET. FORECASTED PATCHY FOG MON MORNING, AS NAM FORECAST SOUNDINGS SHOW A STRONG SURFACE INVERSION MON MORNING; AND NAM AND GFS MOS VALUES SHOW LOW TEMPERATURES GOING NEAR OR BELOW CROSSOVER VALUES BASED ON CURRENT SURFACE DEW POINTS IN THE WELL MIXED BOUNDARY LAYER. DAYTIME MON SHOULD BE MAINLY SUNNY AS ONLY SCATTERED DAYTIME CUMULUS EXPECTED UNDER SURFACE HIGH PRESSURE. HIGH TEMPS WILL BE CLOSE TO NAM AND GFS VALUES. && .LONG TERM (TUE THROUGH SUN)... FOR MID WEEK, FRONT SAGS ACRS THE LAKES. 30% CHC TUE IN NRN ZONES; 20% S. ONLY 20% CHC TUE NIGHT, BEHIND H5 VORT, IF WE CAN BELIEVE THE TIMING OF GFS. 30% CHC WED AFTN IS MAINTAINED, AS ANOTHER SHORT WAVE MOVES E. AND THE SAME THING HAPPENS EARLY THU (RAIN ENDS) AND THU AFTN (DIURNAL TSTMS). ANOTHER SHORT WAVES COMES IN THU NIGHT, SO DROPS STAY ABV 30%, AND EVEN REACH 45% FRI, WHEN MORE VIGOROUS FRONT ENTIRELY ACROSS FCST AREA. BEHIND THE FRONT SAT, TEMPS AND DEWPTS GO DOWN A FEW DEGREES, BUT POPS STAYS 30-40%. CONTINUED TROFFINESS SAT MAY PROVIDE WEATHER MUCH LIKE THE TROFFINESS OF TODAY. POPS FALL INTO THE 20S% SUN, WHICH MIGHT BE THE DAY WITH THE LEAST PRECIP OF THIS NEXT ZONAL FLOW REGIME. && .AVIATION... PREVAILING VISIBILITY UNRESTRICTED (P6SM) INTO LATE TONIGHT WITH SCATTERED TO BROKEN CUMULUS CLOUDS (SCT-BKN030-040) UNTIL SUNSET. ISOLATED SHOWERS WILL MOVE EASTWARD ACROSS NORTHWEST PENNSYLVANIA. LATE TONIGHT, NAM MODEL RUN SOUNDINGS SHOW A STRONG SURFACE INVERSION FORMING. WITH CURRENT SURFACE DEW POINTS IN A WELL MIXED BOUNDARY LAYER INDICATING A CROSSOVER VALUE IN THE UPPER 50S AND MORNING LOW TEMPS GOING NEAR OR BELOW THAT VALUE, EXPECT PATCHY FOG WITH IFR VISIBILITIES (2SM BR) 08Z-12Z. DURING MON, EXPECT DAYTIME CUMULUS TO REDEVELOP BUT WITH LESS COVERAGE THAN TODAY (SCT040). WINDS WILL BE LIGHT TONIGHT, AND SOUTHWEST 5-8KTS MONDAY, AS SURFACE HIGH PRESSURE MOVES ACROSS THE UPPER OHIO VALLEY AND ADJOINING APPALACHIAN MOUNTAINS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ pa AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1137 AM CDT SUN JUL 23 2006 .AVIATION... SOME MID-HIGH CLOUDS MOVING IN FROM EAST. NOT TOO CONCERNED ABOUT THE SHOWERS THERE...WEAK FRONTOGENESIS AT 700MB HELPING THEM GO...BUT TOPS ARE GENERALLY BELOW FL200 AND INSTABILITY IS MARGINAL. MODELS NOT HANDLING THIS AREA TOO WELL...WITH GFS TRYING TO MOVE IT EAST AND WEAKEN AND RUC MOVING IT SW AND WEAKEN. OVERNIGHT...NORTH FLOW WILL WEAKEN AND TURN BACK SOUTH BY MORNING. GFS INDICATING SEA BREEZE TYPE TSTMS TOMORROW FOR WACO AREA...BUT IT HAS BEEN OVERDOING THAT KIND OF PRECIP LATELY AND I WILL NOT BITE ON IT JUST YET. 84 && .UPDATE... 1055 AM ISOLATED SHOWERS CONTINUE OVER THE NORTHEAST ZONES. THESE ELEVATED SHOWERS ARE A RESULT OF WEAK LIFT AND INSTABILITY ASSOCIATED WITH A MID LEVEL TROUGH ROTATING THROUGH THAT REGION. WE EXPECT THE ACTIVITY TO SHIFT SOUTHWARD THIS AFTERNOON WITH THE TROUGH. WILL KEEP SOME ISOLATED SHOWERS/STORMS MENTIONED IN THE NORTHEAST TO ACCOUNT FOR LINGERING EARLY AFTERNOON ACTIVITY. AM A LITTLE CONCERNED ABOUT AFTERNOON HIGH TEMPERATURES BASED ON YESTERDAYS POST FRONTAL WARMUP. EVEN THOUGH CURRENT TEMPERATURES ARE NEAR OR SLIGHTLY ABOVE WHERE THEY WERE YESTERDAY...850 TEMPS ARE ABOUT 6 DEGREES COOLER THAN YESTERDAY. HAVE DECIDED TO BUMP TEMPS UP A DEGREE OR TWO FROM THE CURRENT FORECASTED HIGHS DUE TO ABUNDANT SUN AND EXTREMELY DRY GROUND. ONLY OTHER CHANGES WILL BE SOME MINOR TEMP/DEWPOINT AND CLOUD TWEAKS...79 && .AVIATION... 555 AM CDT... WEAK COOL FRONT ALONG A KLFK-KSJT LINE AT 1030Z MOVING SLOWLY SOUTH. EXPECTED FRONT TO STALL BEFORE REACHING THE COAST AND THEN MOVE BACK NORTH LATE TONIGHT. SCT TSRA ARE EXPECTED SOUTHEAST OF A KPRX-KBBD LINE THROUGH TONIGHT. HOWEVER...WITH THE FRONT SOUTH OF KACT...DOUBT IF ANY WILL AFFECT KACT UNTIL MONDAY. SKIES SHOULD REMAIN VFR THIS TAF CYCLE. WINDS NE LT 10KTS TODAY THEN TURNING TO THE SE LATE TONIGHT. 75 && .DISCUSSION... 313 AM. COLD FRONT BROUGHT DRIER AND SOMEWHAT COOLER AIR....ALTHOUGH MID TO UPPER 90S IS MORE NORMAL FOR THIS TIME OF YEAR. STILL...IT WILL BE A PLEASANT MORNING TODAY AND MONDAY BEFORE RETURN FLOW BRINGS WARMER TEMPS AND HIGHER DEW POINTS BACK TO THE REGION. WITH THE FRONT LAYING CLOSE TO THE SOUTHERN PORTION OF THE CWA...WE CAN EXPECT TO SEE SOME CONVECTION CONTINUE THIS MORNING AND REDEVELOP AGAIN LATER TODAY ACROSS THE SOUTHEASTERN PORTION. IN FACT...THIS AREA WILL LIKELY BE THE ONLY AREA TO SEE RAIN DURING THE COMING WEEK. AFTER SOUTHERLY FLOW RETURNS...A WEAK UPPER LOW WITH TROPICAL CONNECTIONS WILL MAKE ITS WAY ONTO THE UPPER TEXAS COAST. THIS WILL BRING A CHANCE OF RAIN INTO OUR SOUTHEASTERN CWA DURING THE WEEK. SHOWERS MAY WORK THEIR WAY UP TO SOUTHERN PORTIONS OF THE METROPLEX BUT DO NOT SEE MUCH OF THE AREA RECEIVING ANY RAIN...ESPECIALLY TO THE NORTH AND WEST. THE UPPER RIDGE OVER THE WESTERN STATES WILL GRADUALLY FLATTEN AS THE WESTERLIES KEEP A TROUGH OVER THE EASTERN PART OF THE NATION. WHILE WE WILL BE NEAR NORMAL TEMPERATURES EARLY...WE WILL WARM UP TOWARD THE CENTURY MARK AS THE WEEK PROGRESSES. && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 95 72 96 75 / 10 0 10 10 WACO, TX 96 71 95 73 / 20 10 10 10 PARIS, TX 92 68 94 71 / 10 0 10 10 DENTON, TX 94 71 96 74 / 10 0 10 10 MCKINNEY, TX 94 71 96 74 / 10 0 10 10 DALLAS, TX 95 73 96 75 / 10 0 10 10 TERRELL, TX 95 71 95 74 / 10 10 10 10 CORSICANA, TX 95 71 95 73 / 20 10 10 10 TEMPLE, TX 96 71 94 72 / 20 20 20 20 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 75/42 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE WAKEFIELD VA 1210 PM EDT SUN JUL 23 2006 .SHORT TERM /REST OF TONIGHT/... SENT ANOTHER UPDATE...FRONT PASSED THRU AKQ WITH BRIEF HVY SHWR HERE AT THE OFFICE A FEW MINUTES AGO. NNE FLOW BEHIND THE FRONT WILL LIMIT THUNDER ACTIVITY...BUT STRG UPR DIV AND DECENT MID LVL LAPSE RATES MAY SET OFF AN ISO TSTM THRU MID AFTN SO HAVE LEFT SCHC THUNDER MENTION FOR CNTRL VA/MD. STILL HIGHEST CHC FOR SHWRS/TSTMS ACRS FAR SE VA/NE NC. && .PREV DISCUSSION... (ISSUED 915 AM EDT SUN JUL 23 2006) SHORT TERM /REST OF TODAY/... HAVE UPDATED ZONES BASED ON CURRENT RADAR AND SATL TRENDS. FRONT CURRENTLY ALIGNED FROM NEAR DCA TO FVX...A BIT FURTHER INTO OUR CWA THAN PREV EXPECTED. DEW PTS INTO THE 60S AT CHO AND DAN. MCLDY SKIES PREVAIL FOR ALL BUT SE ZONES. FOR REMAINDER OF TODAY HAVE DROPPED THE HVY RAIN WORDING FOR ALL EXCEPT SE ZONES (WHERE SOME SOME THIS MRNG WILL AID HTG/INSTABILITY)...AND HAVE DROPPED IT ALTOGETHER FOR TONIGHT. HAVE ALSO SCALED BACK TO JUST CHC OR SCHC FOR THUNDER FOR THIS AFTN ACRS CNTRL VA AND MD. THE SE ZONES WILL ALSO REMAIN IN THE MORE SOUPY LWR TO MID 70 DEW PTS...AND THIS LINES UP WELL W/ LOCATION OF SLGT RSK FOR SVR THIS AFTN. TEMPS GNRLY LEFT AS IS. PREV DISCUSSION... (ISSUED 437 AM EDT SUN JUL 23 2006) SHORT TERM /TODAY THROUGH TONIGHT/... MODELS CONTINUE TO WREAK HAVOC ON SHORT TERM FORECAST. UTILIZING BLEND OF RUC/NAM FOR THIS AM. FRONT HAVING A SLOWER PROGRESSION OF ITS MOVEMENT SOUTHWARD AND WILL PLAY THE SLOWER ROLE OF PROGRESSION SOUTHWARD THAN SHORT RANGE GUIDANCE CURRENTLY PREDICTS. LAST EVENINGS ACTIVITY PRODUCED A LARGE SWATH OF 1 TO 2 INCHES OF PRECIP OVER THE NWRN 2/3RDS WITH LOCALLY HIGHER AMOUNTS WHERE STORMS CONTINUED TO MOVE OVER. CURRENTLY QUASI STATIONARY FRONT SITUATED FROM NEW ENGL INTO GA. NUMEROUS SHRTWVS CONTINUE TO RIDE NORTHEASTWARD ALONG IT. THIS EARLY AM ONE CURRENTLY SPREADING A BATCH OF PRECIP OVER NWRN 1/3RD OF CWA. WENT LOW POP OVER FAR SE WITH BETTER FORCING/DYNAMICS RIGHT ALONG FRONT. SHOULD SEE BREAKS IN CLOUD SHIELD OVER SERN THIRD OF CWA ADDING TO INSTABILITY TO DVLP. FRONTAL SYSTEM WILL SLOWLY PUSH ESE THIS AFTN-EVE AS H50 LOW OVER INDIANA ACTS AS A KICKER. INTERESTING THAT THE GFS/NAM ALREADY TO FAR EAST WITH H50 LOW SHOWN WELL ON WV IMAGERY (GFS FURTHER OFF). UNTIL THIS SYSTEM MOVES INTO THE MID-ATL THERE WILL BE NO REASON FOR FRONT TO SAG FURTHER TO THE SE. SHRTWV THIS AFTN/EVE WILL MOVE NE ALONG FRONT FROM THE CAROLINAS INTO SE VA. THIS WILL ACT AS A BLOCKING MECHANISM...ALSO AIDING TO THE SLOWER TIMING OF A SOUTHEASTWARD PROGRESSION OF THE FRONT AND MAY ENHANCE PRECIP TO LINGER ALONG THE COAST ZONES. BUFKIT CLOUD VECTOR LAYER DOES NOT MOVE FROM NE TO W/NW TILL LATE EVE OVER NWRN THIRD OF CWA (CUTTING OFF PRECIP POTENTIAL). PRECIP MAY LINGER HALFWAY THROUGH THE OVERNIGHT OVER SOUTHEASTERN THIRD SO KEPT LOW CHC POPS IN BEFORE FRONT FINALLY SAGS SOUTH OF CWA. THE SOUTHEASTERN THIRD OF THE CWA SHOULD SEE A GOOD DOSE OF MAIN...MUCH LIKE THE NW DID LAST EVENING. GENERALLY A SWATH OF 1 TO 2 INCHES WILL BE POSSIBLE WITH LOCALLY HIGHER/LOWER AMOUNTS POSSIBLE. STORM MOVEMENT WILL ONCE AGAIN CONTINUE TO BE MAINLY SW TO NE. FAR SE IS IN OUTLOOK FOR SVR THREAT THIS AFTN/EVE. VAD WIND PROFILE ALREADY SHOWING LOW LVL JET ENHANCEMENT ALREADY IN PLACE OVER REGION. ENTRANCE RGN OF UPR LVL JET CURRENTLY OVER CNTRL KY WILL SLIDE SE AS H50 LOW MOVES INTO WV/PA. TIMING OF UPR LVL JET FORCING WILL BE CRITICAL TO THE CHC FOR SVR WX TO DVLP OVER FAR SE CWA LATER TODAY (MAINLY TWDS EVE). MAIN THREAT WILL BE FOR DAMAGING WINDS. THINKING BEST CHANCES FOR SVR WX THREAT WILL BE OVER THE CAROLINAS. IF CONVECTION KICKS UP BY LATE MORNING OVER SC THIS MAY INHIBIT WIDESPREAD STRONG TO SVR STORM DVLPMNT FURTHER N INTO OUR NECK OF THE WOODS. LONG TERM /MONDAY THROUGH SATURDAY/... MON LOOKS DRY FOR THE REGION...BUT GFS HINTING AT ANOTHER SHRTWV MOVING OUT OF THE SOUTHEASTERN CONUS INTO THE CAROLINAS ALONG THE SLOWLY SAGGING (OR STALLED) FRONT MON NIGHT INTO TUE. FOR NOW LEFT DRY ON MON AND WENT LOW POPS FOR TUE AS NAM NOT AS AGGRESSIVE WITH NORTHWARD PUSH OF SHRTWV. FURTHER OUT COMPLICATED WITH SHRTWVS RIDING ALONG NRN PERIPHERY OF RIDGE THAT WILL BE SITUATED OVER THE WESTERN HALF OF THE CONUS. UPR LVL JET STREAKS WILL PUSH OUT OF CENTRAL CANADA INTO THE MISSISSIPPI VLY AIDING TO TROF ENHANCEMENT OVER THE EASTERN CONUS AT TIMES. TOO EARLY TO TIME/PINPOINT PRECIP CHCS MID/LATE WK...BUT MAINLY ANY ACTIVITY LIKELY WOULD BE LATE DAY. AVIATION... SCT MVFR...ISLD IFR CONDITIONS CURRENTLY BEING OBSERVED EARLY THIS MORNING WILL CONTINUE PERIODICALLY THROUGH THE DAY AS ADDITIONAL SHOWERS AND TSTMS FROM ALONG AND E-SE OF THE FRONTAL BOUNDARY. ANTICIPATE GRADUALLY CLEARING TONIGHT FROM N-S...HOWEVER SINCE GROUND WILL BE RELATIVELY MOIST GIVEN VERY LITTLE MIXING/DRYING TODAY...WOULD EXPECT AREAS OF FOG (MVFR/IFR VSBYS) TO DEVELOP. MARINE... SMALL CRAFT ADVISORIES OVER CHES BAY AND CURRITUCK SOUND WILL BE ENDING WITHIN A FEW HOURS...AS THE SW LOW LEVEL JET (35-40 KTS AT 2-3 KFT) SHIFTS OFF TO THE EAST. OVER THE COASTAL WATERS WILL MAINTAIN THE SMALL CRAFT ADVISORY THROUGH NOON...AS THE FLOW BECOMES MORE OFFSHORE AND SEAS BEGIN TO TAPER BELOW SCA CRITERIA. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SHORT TERM...BROWN va AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE WAKEFIELD VA 915 AM EDT SUN JUL 23 2006 .SHORT TERM /REST OF TODAY/... HAVE UPDATED ZONES BASED ON CURRENT RADAR AND SATL TRENDS. FRONT CURRENTLY ALIGNED FROM NEAR DCA TO FVX...A BIT FURTHER INTO OUR CWA THAN PREV EXPECTED. DEW PTS INTO THE 60S AT CHO AND DAN. MCLDY SKIES PREVAIL FOR ALL BUT SE ZONES. FOR REMAINDER OF TODAY HAVE DROPPED THE HVY RAIN WORDING FOR ALL EXCEPT SE ZONES (WHERE SOME SOME THIS MRNG WILL AID HTG/INSTABILITY)...AND HAVE DROPPED IT ALTOGETHER FOR TONIGHT. HAVE ALSO SCALED BACK TO JUST CHC OR SCHC FOR THUNDER FOR THIS AFTN ACRS CNTRL VA AND MD. THE SE ZONES WILL ALSO REMAIN IN THE MORE SOUPY LWR TO MID 70 DEW PTS...AND THIS LINES UP WELL W/ LOCATION OF SLGT RSK FOR SVR THIS AFTN. TEMPS GNRLY LEFT AS IS. && .PREV DISCUSSION... (ISSUED 437 AM EDT SUN JUL 23 2006) SHORT TERM /TODAY THROUGH TONIGHT/... MODELS CONTINUE TO WREAK HAVOC ON SHORT TERM FORECAST. UTILIZING BLEND OF RUC/NAM FOR THIS AM. FRONT HAVING A SLOWER PROGRESSION OF ITS MOVEMENT SOUTHWARD AND WILL PLAY THE SLOWER ROLE OF PROGRESSION SOUTHWARD THAN SHORT RANGE GUIDANCE CURRENTLY PREDICTS. LAST EVENINGS ACTIVITY PRODUCED A LARGE SWATH OF 1 TO 2 INCHES OF PRECIP OVER THE NWRN 2/3RDS WITH LOCALLY HIGHER AMOUNTS WHERE STORMS CONTINUED TO MOVE OVER. CURRENTLY QUASI STATIONARY FRONT SITUATED FROM NEW ENGL INTO GA. NUMEROUS SHRTWVS CONTINUE TO RIDE NORTHEASTWARD ALONG IT. THIS EARLY AM ONE CURRENTLY SPREADING A BATCH OF PRECIP OVER NWRN 1/3RD OF CWA. WENT LOW POP OVER FAR SE WITH BETTER FORCING/DYNAMICS RIGHT ALONG FRONT. SHOULD SEE BREAKS IN CLOUD SHIELD OVER SERN THIRD OF CWA ADDING TO INSTABILITY TO DVLP. FRONTAL SYSTEM WILL SLOWLY PUSH ESE THIS AFTN-EVE AS H50 LOW OVER INDIANA ACTS AS A KICKER. INTERESTING THAT THE GFS/NAM ALREADY TO FAR EAST WITH H50 LOW SHOWN WELL ON WV IMAGERY (GFS FURTHER OFF). UNTIL THIS SYSTEM MOVES INTO THE MID-ATL THERE WILL BE NO REASON FOR FRONT TO SAG FURTHER TO THE SE. SHRTWV THIS AFTN/EVE WILL MOVE NE ALONG FRONT FROM THE CAROLINAS INTO SE VA. THIS WILL ACT AS A BLOCKING MECHANISM...ALSO AIDING TO THE SLOWER TIMING OF A SOUTHEASTWARD PROGRESSION OF THE FRONT AND MAY ENHANCE PRECIP TO LINGER ALONG THE COAST ZONES. BUFKIT CLOUD VECTOR LAYER DOES NOT MOVE FROM NE TO W/NW TILL LATE EVE OVER NWRN THIRD OF CWA (CUTTING OFF PRECIP POTENTIAL). PRECIP MAY LINGER HALFWAY THROUGH THE OVERNIGHT OVER SOUTHEASTERN THIRD SO KEPT LOW CHC POPS IN BEFORE FRONT FINALLY SAGS SOUTH OF CWA. THE SOUTHEASTERN THIRD OF THE CWA SHOULD SEE A GOOD DOSE OF MAIN...MUCH LIKE THE NW DID LAST EVENING. GENERALLY A SWATH OF 1 TO 2 INCHES WILL BE POSSIBLE WITH LOCALLY HIGHER/LOWER AMOUNTS POSSIBLE. STORM MOVEMENT WILL ONCE AGAIN CONTINUE TO BE MAINLY SW TO NE. FAR SE IS IN OUTLOOK FOR SVR THREAT THIS AFTN/EVE. VAD WIND PROFILE ALREADY SHOWING LOW LVL JET ENHANCEMENT ALREADY IN PLACE OVER REGION. ENTRANCE RGN OF UPR LVL JET CURRENTLY OVER CNTRL KY WILL SLIDE SE AS H50 LOW MOVES INTO WV/PA. TIMING OF UPR LVL JET FORCING WILL BE CRITICAL TO THE CHC FOR SVR WX TO DVLP OVER FAR SE CWA LATER TODAY (MAINLY TWDS EVE). MAIN THREAT WILL BE FOR DAMAGING WINDS. THINKING BEST CHANCES FOR SVR WX THREAT WILL BE OVER THE CAROLINAS. IF CONVECTION KICKS UP BY LATE MORNING OVER SC THIS MAY INHIBIT WIDESPREAD STRONG TO SVR STORM DVLPMNT FURTHER N INTO OUR NECK OF THE WOODS. LONG TERM /MONDAY THROUGH SATURDAY/... MON LOOKS DRY FOR THE REGION...BUT GFS HINTING AT ANOTHER SHRTWV MOVING OUT OF THE SOUTHEASTERN CONUS INTO THE CAROLINAS ALONG THE SLOWLY SAGGING (OR STALLED) FRONT MON NIGHT INTO TUE. FOR NOW LEFT DRY ON MON AND WENT LOW POPS FOR TUE AS NAM NOT AS AGGRESSIVE WITH NORTHWARD PUSH OF SHRTWV. FURTHER OUT COMPLICATED WITH SHRTWVS RIDING ALONG NRN PERIPHERY OF RIDGE THAT WILL BE SITUATED OVER THE WESTERN HALF OF THE CONUS. UPR LVL JET STREAKS WILL PUSH OUT OF CENTRAL CANADA INTO THE MISSISSIPPI VLY AIDING TO TROF ENHANCEMENT OVER THE EASTERN CONUS AT TIMES. TOO EARLY TO TIME/PINPOINT PRECIP CHCS MID/LATE WK...BUT MAINLY ANY ACTIVITY LIKELY WOULD BE LATE DAY. AVIATION... SCT MVFR...ISLD IFR CONDITIONS CURRENTLY BEING OBSERVED EARLY THIS MORNING WILL CONTINUE PERIODICALLY THROUGH THE DAY AS ADDITIONAL SHOWERS AND TSTMS FROM ALONG AND E-SE OF THE FRONTAL BOUNDARY. ANTICIPATE GRADUALLY CLEARING TONIGHT FROM N-S...HOWEVER SINCE GROUND WILL BE RELATIVELY MOIST GIVEN VERY LITTLE MIXING/DRYING TODAY...WOULD EXPECT AREAS OF FOG (MVFR/IFR VSBYS) TO DEVELOP. MARINE... SMALL CRAFT ADVISORIES OVER CHES BAY AND CURRITUCK SOUND WILL BE ENDING WITHIN A FEW HOURS...AS THE SW LOW LEVEL JET (35-40 KTS AT 2-3 KFT) SHIFTS OFF TO THE EAST. OVER THE COASTAL WATERS WILL MAINTAIN THE SMALL CRAFT ADVISORY THROUGH NOON...AS THE FLOW BECOMES MORE OFFSHORE AND SEAS BEGIN TO TAPER BELOW SCA CRITERIA. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FOR ANZ650-652-654 UNTIL NOON SUNDAY. && $$ SHORT TERM UPDATE...BROWN va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 300 PM CDT SUN JUL 23 2006 .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT FORECAST CONCERNS CENTERED ON PRECIPITATION CHANCES THROUGH THE PERIOD ALONG WITH TEMPERATURES. ALSO SEVERE WEATHER THREAT MONDAY A CONCERN. 18Z SURFACE ANALYSIS SHOWS WEAK FRONTAL BOUNDARY EXTENDING FROM CENTRAL SOUTH DAKOTA INTO NORTHWEST MINNESOTA. WATER VAPOR IMAGERY SHOWS A SHORTWAVE JUST SOUTH OF LAKE WINNIPEG MOVING SOUTHWARD IN THE NORTHWEST FLOW ALOFT. CONVECTION DEVELOPED EARLIER TODAY AHEAD OF THE FRONT AND SHORTWAVE AND IS NOW LOCATED FROM THE ARROWHEAD OF MINNESOTA INTO UPPER MICHIGAN. VISIBLE SATELLITE IMAGERY SHOWS CUMULUS FIELD DEVELOPING SOUTHWARD ACROSS THE FORECAST AREA. 12 23JUL06 IN DECENT AGREEMENT WITH THE OVERALL PATTERN...BUT STILL SHOW DIFFERENCES IN THE DETAILS...ESPECIALLY WITH THE HANDLING OF THE FRONTAL BOUNDARY ON MONDAY. NAM CONTINUES TO BE A LITTLE FASTER THAN THE GFS AND IN FACT ITS TREND FROM ITS PREVIOUS RUNS HAVE BEEN FASTER AND WEAKER. HAVE USED A BEND OF THE GFS/NAM IN HANDLING THE FRONTAL POSITION ON MONDAY. FOR TONIGHT...SHORTWAVE TO DIVE INTO THE AREA. THE NAM/GFS AND RUC ALL SIMILAR IN DEVELOPING SOME QPF ACROSS THE AREA DURING THE OVERNIGHT HOURS. WITH NAM INDICATING MOISTURE TRANSPORT ACROSS THE AREA TONIGHT AND COMBINED WITH SOME 850MB THETA E ADVECTION AND WARM ADVECTION AHEAD OF THE TROUGH HAVE DECIDED TO ADD SOME LOW POPS ACROSS THE AREA. FEEL NAM BY BE A LITTLE TOO ROBUST WITH ITS QPF THOUGH. BUT CERTAINLY ENOUGH SIGNAL THERE TO WARRANT POPS. FRONTAL BOUNDARY TO SAG INTO THE AREA ON MONDAY AS MAIN SHORTWAVE ROTATES ACROSS THE SOUTHERN ONTARIO. SURFACE DEW POINTS IN THE LOWER TO MIDDLE 60S WILL CONTRIBUTE TO MLCAPES BETWEEN 1000 AND 2000 J/KG. HOWEVER...STRONG SHEAR TO REMAIN WELL NORTH OF THE AREA IN VICINITY OF SHORTWAVE...WITH MODELS ONLY SHOWING AROUND 20 TO 25 KNOTS OF SHEAR IN THE LOWEST 3 KM OF THE ATMOSPHERE. WITH CONVERGENCE ALONG BOUNDARY WILL SEE STRONGER CONVECTION IN THE AFTERNOON. THE MONDAY NIGHT THROUGH WEDNESDAY NIGHT TIME FRAME WILL DOMINATED BY A NEARLY ZONAL FLOW. BIGGEST QUESTION WILL BE POSITIONING OF THE AFOREMENTIONED FRONTAL BOUNDARY AND TIMING OF IMPULSES IN THE FLOW. EXPECT BOUNDARY TO HANG AROUND THE AREA THROUGH MUCH OF THE PERIOD. RATHER DIFFICULT TO ADD ANY DETAIL TO THE GRIDS SO NO CHANGES MADE AS LOW POPS THROUGH THIS TIME FRAME LOOKS GOOD. EXACT POSITION OF FRONT ON MONDAY WILL HAVE INFLUENCE ON TEMPERATURES. WITH THE NAM BEING THE FASTEST...ITS CORRESPONDING TEMPERATURES ARE COOLER THAN THE GFS...THIS ESPECIALLY TRUE ACROSS OUR NORTHERN COUNTIES. NOTICED THAT MET NUMBERS ARE A LITTLE HIGHER THAN YESTERDAY BUT STILL NOT AS WARM AS THE MAV. WITH QUESTIONS ABOUT FRONTAL POSITION/CONVECTION AND CLOUDS...HAVE USED A COMPROMISE OF GUIDANCE VALUES...WHICH IS IN LINE WITH THE CURRENT GRIDDED DATA BASE. .LONG TERM...THURSDAY THROUGH SUNDAY STILL SOME PROBLEMS WITH THE MEDIUM RANGE MODELS WITH THE DAY TO DAY DETAILS. NCEP ENSEMBLE MEANS IS SHOWING A RATHER ZONAL FLOW PATTERN ACROSS MOST OF THE CONUS DURING THIS PERIOD. MODEL SOLUTIONS HAVE BEEN CONSISTENT LAST SEVERAL RUNS IN WANTING TO BUILD A RIDGE OUT IN THE PACIFIC BETWEEN ALASKA AND HAWAII. THIS IN TURN WOULD RESULT IN WEAK TROUGHING NEAR THE WEST COAST WITH WEAK RIDGING ACROSS THE CENTRAL CONUS. SEVERAL WAVES LOOK TO AFFECT THE AREA DURING THE EARLY PART OF THE PERIOD PUSHING THE FRONTAL BOUNDARY THROUGH THE FORECAST AREA. THUS HAVE CONTINUED LOW POPS THURSDAY. STILL SOME QUESTION AS TO HOW FAR SOUTH THIS GETS PUSHED. HOWEVER...WITH ENSEMBLES INDICATING RISING HEIGHTS INTO THE WEEKEND...EXPECT FRONT TO LAY UP SOMEWHERE SOUTH OF THE REGION WITH DRY WEATHER EXPECTED ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. IN ADDITION ALSO EXPECT RATHER WARM CONDITIONS...WITH HIGHS GENERALLY IN THE MIDDLE TO UPPER 80S. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ RABERDING wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 405 AM EDT MON JUL 24 2006 .SHORT TERM... TODAY AND TONIGHT. RIDGE AXIS HAS NOW SHIFTED EAST OF THE FORECAST AREA...ALLOWING WAA TO BEGIN. 850 MB TEMPS WILL CLIMB INTO THE UPPER TEENS BY AFTERNOON. THIS COMBINED WITH WHAT SHOULD BE A GOOD DEAL OF SUNSHINE...AT LEAST TO START WITH...WILL ALLOW TEMPS TO CLIMB BACK TO NORMAL OR EVEN SLIGHTLY ABOVE NORMAL LEVELS TODAY. DEWPTS WILL ALSO BE ON THE INCREASE WITH READINGS IN THE LOW TO MID 60S COMMON UPSTREAM. FRONTAL BOUNDARY MAKING SLOW PROGRESS SOUTH FROM MINNESOTA AND LK SUPERIOR. LINE OF SHOWERS AND STORMS IN ADVANCE OF THIS DIVING SOUTH AND EAST INTO NORTHERN LWR MI...POSING NO CONCERN. A SMALL LINE OF SHOWERS AND STORMS HAS DEVELOPED OVER THE PAST HOUR EAST OF LACROSSE WISCONSIN. PROFILER DATA IS MISSING AT THIS TIME...BUT RUC SHOWS A 30+KT LLJ FEEDING INTO THIS AREA WITH INCREASING LOW LEVEL THETA-E. TRENDS AND 850-300 MB THICKNESS PLOTS SHOW THIS ACTIVITY SHOULD ALSO DRIFT INTO MICHIGAN AND POSE NO THREAT. WILL NEED TO MONITOR TRENDS TO MAKE SURE BUT WILL MAINTAIN A DRY FORECAST TODAY. CU RULE SHOWS DIURNAL DEVELOPMENT ONCE AGAIN...BUT VALUES NOT AS HIGH AS YESTERDAY. ALSO WITH INCREASING SFC WINDS AS GRADIENT INCREASES AND STRONGER WIND FLOW IS MIXED DOWN SOMEWHAT...LAKE BREEZE DEVELOPMENT UNLIKELY. SCT CU WILL DEVELOP ONCE AGAIN...BUT CU RULE SHOWING NOT AS MUCH COVERAGE AS TODAY. FOCUS BEGINS TO TURN TONIGHT ONTO ABOVE MENTIONED FRONTAL BOUNDARY ACROSS LWR MI THAT WILL BE MAKING SLOW PROGRESS SOUTH. COMPLEX OF STORMS EXPECTED TO DEVELOP AND MOVE ALONG IT TONIGHT. TRACK OF THIS SHOULD REMAIN FAR ENOUGH NORTH TO ALLOW CONTINUED DRY FORECAST TONIGHT. WITH CONTINUED WAA AND INCREASING MSTR LOWS WILL BE A GOOD 10 DEGREE WARMER IN MANY LOCATIONS TONIGHT...DROPPING ONLY TO THE MID TO UPPER 60S. && .LONG TERM... TUESDAY THROUGH SUNDAY. NOT QUITE READY TO THROW LATEST NAM OUT THE WINDOW. SHORTWAVE ENERGY OVER NORTHEAST MT SHOULD CONTINUE TO DAMPEN AS LONGWAVE TROF ACROSS EASTERN STATES DEAMPLIFIES AS NEW ENGLAND WAVE LIFTS NORTHEAST AND GREAT BASIN HIGH SLOWLY WEAKENS AND PUSHES SOUTH WHERE NAM HAS SHOWN RUN TO RUN CONSISTENCY HERE. GFS AND NAM WITH HUGE DISPARITIES WITH REGARDS TO MOS POPS TUESDAY NIGHT...CATAGORICAL VS. LT 20. TUE NIGHT MCS GENERATION PER GFS A BIT SUSPECT WITH CONVECTIVE SCALE FEEDBACK. PREFERENCE LIES TOWARD CONSISTENCY AND NAM AND AWAIT MORE STRONGER ENERGY OVER NORTHWEST TERRITORIES TO DIVE SOUTHEAST INTO CENTRAL CANADA/UPPER PLAINS BY MIDWEEK. DEEP MOIST TRANSPORT AHEAD OF SYSTEM WITH PWAT INCREASING TO NEAR 2 INCHES AND ARRIVAL OF BETTER KINEMATICS/INSTABILITY LATE WEDNESDAY AFTERNOON WITH POTENTIAL MCS DEVELOPMENT UPSTREAM TO MOVE ESE THROUGH SOUTHERN GREAT LAKES WED NIGHT....HAVE RAISED TSRA POPS TO HIGH CHANCE RANGE WED NIGHT AND THROUGH THU FOR POTENTIAL AIRMASS DESTABILIZATION AND LOW LEVEL VEERING AHEAD OF APPROACHING MID LEVEL WAVE THU. NO OTHER CHANGES REMAINDER OF FORECAST. && .AVIATION... SFC RIDGE WILL CONTINUE ITS EASTWARD TRACK...BUT STILL ALLOW FOR VFR CONDITIONS THROUGH THE PERIOD. SOME PASSING CU MAY DEVELOP ONCE AGAIN AND ANY LAKE BREEZE DEVELOPMENT MAY NEED TO BE MONITORED FOR ISOL CONVECTION LIKE YESTERDAY. WINDS WILL BE THE MAIN FOCUS WITH SOME GUSTS IN THE 20 TO 25 KT RANGE POSSIBLE DURING THE AFTN AS STRONG MIXING TAKES PLACE OF HIGHER WINDS IN LOW LEVELS. LATER PERIODS OF THE TAF WILL SEE CLOUDS BEGIN TO STREAM SOUTH FROM UPSTREAM CONVECTION...BUT STILL NO REAL IMPACT ON AVIATION INTERESTS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ AVIATION/SHORT TERM...FISHER LONG TERM....MURPHY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 343 AM EDT MON JUL 24 2006 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT. WATER VAPOR IMAGERY AND RUC SHOWING A LONGWAVE TROUGH OVER THE EASTERN AND SOUTHERN CONUS...A CLOSED LOW OVER NORTHEAST MANITOBA... AND LARGE RIDGE OVER THE SOUTHERN ROCKIES. A WEAK SHORTWAVE SLIDING DOWN THE LEE OF THE ROCKIES RIDGE IS PASSING THROUGH THE WESTERN U.P. ANOTHER WEAK SHORTWAVE IS MOVING THROUGH THE NORTHERN PART OF THE RIDGE AND IS OVER MONTANA. SURFACE ANALYSIS DEPICTS A LOW OVER NORTHERN ONTARIO IN CONJUNCTION WITH THE UPPER LEVEL LOW. A COLD FRONT DRAPED FROM THIS LOW IS OVER NORTHWEST MINNESOTA...NORTH DAKOTA...AND NORTHEAST MONTANA THIS MORNING. A 1009MB HIGH IS PUSHING THIS FRONTAL SYSTEM SOUTH. THE MID LEVEL LOW WILL SLIDE INTO NORTHERN ONTARIO. A SHORTWAVE WRAPPING AROUND THE BASE OF THIS LOW WILL SWEEP INTO CENTRAL ONTARIO. THE WEAK SHORTWAVE OVER WESTERN U.P. WILL SWEEP ACROSS THE REST OF THE FORECAST AREA BY 18Z. ANOTHER SHORTWAVE WILL BE TO THE SOUTHWEST OF THE FORECAST AREA. THE COLD FRONT WILL REACH LAKE SUPERIOR BY SUNRISE...AND WILL PASS THROUGH THE AREA DURING THE DAY. THE HIGH OVER CANADA WILL START TO BUILD INTO NORTH DAKOTA. 850-500MB Q-VECTOR CONVERGENCE WILL BE STRONGEST THIS MORNING OVER THE CENTRAL U.P. THIS WILL SLIDE INTO NORTHERN LAKE MICHIGAN BY NOON. MUCAPE WILL BE AROUND 800J/KG OVER NORTHERN WISCONSIN WITH LOWER AMOUNTS MOVING THROUGH THE U.P. AN 850MB THETA-E RIDGE WILL EXTEND FROM NORTHERN WISCONSIN THROUGH CENTRAL U.P. BY SUNRISE AND THROUGH NORTHERN LAKE MICHIGAN BY LATE AFTERNOON. 300K ISENTROPIC ANALYSIS INDICATE STRONG ASCENT AHEAD OF THE FRONT OVER THE FORECAST AREA THIS MORNING. BY 18Z MOST OF THE ASCENT WILL BE GONE AS THE FRONT MOVES INTO NORTHERN LAKE MICHIGAN. THUS IT LOOKS AS IF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ESPECIALLY OVER THE SOUTHERN U.P. AND OVER THE NORTHERN LAKE SUPERIOR TODAY. A SOUTHWEST FLOW AHEAD OF THE FRONT WILL HELP TO PUSH TEMPERATURES UP AS TEMPERATURES OVER WISCONSIN REMAINED IN THE LOW 70S THIS MORNING. THE TEMPERATURES WILL RISE INTO THE MID 80S BY LATE AFTERNOON AND START TO FALL OFF AFTER THE FRONT SWEEPS THROUGH. ANOTHER WEAK SHORTWAVE WILL SWEEP INTO WESTERN U.P. TONIGHT. A SURFACE LOW WILL DEVELOP OVER CENTRAL CANADA AND MOVE TO NORTHEAST MANITOBA. DRIER AIR WILL MOVE OVER THE NORTHERN PART OF THE FORECAST AREA. HIGHER SURFACE-500MB RH WILL BE OVER NORTHERN WISCONSIN...AND SOUTHERN U.P. MUCAPE ANALYSIS INDICATE THAT THERE WILL BE VALUES AROUND 1000J/KG ALONG THE WISCONSIN BORDER AND OVER THE SOUTHERN U.P. WILL LEAVE A CHANCE OF SHOWERS AND THUNDERSTORMS FOR TONIGHT IN THOSE AREAS. THE WEAK SHORTWAVE WILL SLIDE INTO EASTERN LAKE SUPERIOR ON TUESDAY. MEANWHILE...ANOTHER SHORTWAVE WILL DEVELOP OVER CENTRAL CANADA AND MOVE INTO ONTARIO JUST NORTHWEST OF LAKE SUPERIOR. A WEAK CLOSED LOW IS EXPECT TO DEVELOP OVER WISCONSIN. CAPE VALUES WILL REACH 1300-1700J/KG ACROSS THE U.P. JUST NORTHEAST OF THIS LOW. AN 850MB THETA-E RIDGE WILL BECOME FOCUSED ACROSS THE U.P. FROM WEST TO EAST AS WILL THE HIGHEST RH. A SURFACE LOW WILL DEVELOP OVER SOUTH CENTRAL CANADA AND MOVE INTO NORTHERN MINNESOTA. ISENTROPIC ASCENT WILL INCREASE AHEAD OF THIS LOW. THUS WILL KEEP THUNDERSTORMS POSSIBLE THROUGH TUESDAY. AS THE WISCONSIN SHORTWAVE MOVES EAST ACROSS THE SOUTHERN U.P. TUESDAY NIGHT...ANOTHER SHORTWAVE WILL SWEEP ACROSS THE NORTH PART OF THE FORECAST AREA AS AN EVEN DEEPER SHORTWAVE WILL SWING INTO WESTERN LAKE SUPERIOR. THE SURFACE LOW WILL MOVE OUT OF MINNESOTA INTO NORTHWEST WISCONSIN. THE MEAN SURFACE-500MB RH AND ASSOCIATED 850MB THETA-E RIDGE WILL SLIDE INTO WESTERN U.P. AS ANOTHER LEAVES THE AREA. A SERIES OF WEAK SHORTWAVE WILL SLIDE THROUGH THE FORECAST AREA WEDNESDAY THROUGH THURSDAY. Q-VECTOR CONVERGENCE...ISENTROPIC ASCENT...AND ACCOMPANYING THETA-E RIDGES SUGGEST A CHANCE OF THUNDERSTORMS THROUGH THIS PERIOD. DRIER...MORE STABLE AIR MASS WILL DOMINATE THE FORECAST AREA ON FRIDAY INTO SATURDAY MORNING. A SHORTWAVE WILL SLIDE INTO THE WISCONSIN AS AN ASSOCIATED SURFACE RIDGE STARTS TO SLIDE OFF TO THE EAST. A CHANCE OF SHOWERS AND THUNDERSTORMS WILL THUS RETURN SATURDAY AFTERNOON THROUGH SUNDAY. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 101 AM EDT MON JUL 24 2006 .AVIATION... THINNING CIRRUS SHIELD WILL BE THE ONLY STORY TONIGHT. ON MONDAY...WINDS WILL FRESHEN QUICKLY DURING THE MORNING AS THE PRESSURE GRADIENT INCREASES IN ADVANCE OF THE NEXT SURFACE BOUNDARY. VIGOROUS BOUNDARY LAYER MIXING WILL PROMOTE GUSTY CONDITIONS FROM LATE MORNING ON. NAM SOUNDINGS STILL SUPPORT SAMPLING 30+KT FLOW...WHICH SHOULD REALIZE IN THE 20-25KT NEIGHBORHOOD. LOW-LEVEL TROUGH AXIS WILL REMAIN NORTH OF THE FORECAST AREA THROUGH THE PERIOD...HOWEVER CONVECTION SHOULD DEVELOP ACROSS NORTHERN/WESTERN LOWER DURING THE AFTERNOON AND START TO MAKE INROADS INTO THE FORECAST AREA DURING THE LATE AFTERNOON AND EARLY EVENING. WILL CARRY PROB GROUP IN THE NORTHERN SITES FOR THUNDER IN THE POST 22Z TIME WINDOW...BUT WITH THE BOUNDARY HANGING OUT ACROSS NORTHERN LOWER WILL REFRAIN FROM THUNDER MENTION AT THE SOUTHERN SITES. && .PREV DISCUSSION...ISSUED 404 PM EDT SUN JUL 23 2006 SHORT TERM...TONIGHT AND MONDAY 12Z RAOBS/WATER VAPOR LOOP SHOW AN AMPLIFIED PATTERN WITH A STRONG RIDGE OVER THE WESTERN CONUS AND TROUGH OVER THE GREAT LAKES. ONE SHORTWAVE EMBEDDED WITHIN THE LONGWAVE TROUGH WAS OVER LAKE HURON...WHILE OTHERS WERE UPSTREAM NEAR THE APOSTLE ISLANDS AND LAKE WINNIPEG. SURFACE ANALYSIS SHOWS BROAD HIGH PRESSURE OVER THE GREAT LAKES AND OHIO VALLEY...WITH A WEAKNESS/TROUGH OVER CENTRAL LOWER MICHIGAN. VIS SATELLITE SHOWS A RATHER MEAGER CU FIELD...EXCEPT ACROSS THE EASTERN CWA NEAR THE GREAT LAKES WHERE LAKE BREEZE CONVERGENCE HAS LED TO MORE ROBUST CLOUDS AS WELL AS PRECIP. REGIONAL RADARS SHOW CONVECTION HAS BEEN BUBBLING FROM NORTHEAST LOWER INTO THE THUMB...WITH A FEW STORMS REACHING A SIGNIFICANT INTENSITY. DECENT INSTABILITY ACROSS SOUTHEAST MICHIGAN...GREAT IN THE THUMB WITH UP TO 1500J/KG CAPE. DEWPOINT ACROSS THE INTERIOR OF THE CWA HAVE MIXED DOWN INTO THE UPPER 40S/LOW 40S...WHICH HAS SEVERELY LIMITED THE AVAILABLE ENERGY. THE ADDED MOISTURE FLUX IN THE ONSHORE FLOW FROM LAKE HURON HAS KEPT DEWPOINTS IN THE UPPER 50S/LOW 60S ACROSS THE THUMB. TAMDAR SOUNDINGS ALSO SHOW A DECENT MID-LEVEL CAP...WHICH HAS LIMITED CONVECTION DEVELOP INLAND AND GROWTH NEAR THE LAKES...WITH ONLY A FEW STORMS BEING ABLE TO PUNCH THROUGH IT. THE SHORTWAVE OVER LAKE HURON WILL TRACK INTO SOUTHEAST ONTARIO THIS EVENING...SO WOULD ONLY EXPECT THE CAP TO STRENGTHEN FURTHER ACROSS THE WESTERN CWA. OTHER THAN THE THUMB...AM ALSO A LITTLE CONCERNED ABOUT THE BETTER CU FIELD ACROSS THE SOUTHEASTERN CWA FROM PORT HURON TO MONROE. IT IS POSSIBLE WE COULD SEE SOME ADDITIONAL DEVELOPMENT ALONG THE LAKE ST CLAIR/ERIE LAKE BREEZES...HOWEVER WITH THE STRONGER CAP IN PLACE WILL ONLY MENTION A SLIGHT CHANCE TSRA IN THE SOUTHEAST...AS OPPOSED TO SCATTERED/ISOLATED ACROSS THE THUMB. THE LAKE WINNIPEG SHORTWAVE WILL SWING EASTWARD TONIGHT...PROPELLING A WARM FRONT INTO THE NORTHERN GREAT LAKES. GFS OVERDEVELOPS A CONVECTIVE COMPLEX ALONG THIS FRONT...AND CONSEQUENTLY IS MUCH SLOWER DROPPING THE BOUNDARY SOUTHWARD ACROSS THE REGION. NAM/NGM/DEVELOPMENTAL RUC SHOW A SIMILAR FASTER TIMING...WHICH IS PREFERRED. THE FRONT REMAINS WELL NORTH OF THE CWA TONIGHT...BUT THERE IS A INCREASE IN MID-LEVEL MOISTURE OVERNIGHT. SOMEWHAT CONCERNED ABOUT THE NOCTURNAL THETA-E ADVECTION PICKING UP AROUND SUNRISE. HOWEVER THE AMOUNT OF CIRRUS IN ADDITION TO THE MID CLOUDS UPSTREAM SHOULD LIMIT THE DEGREE OF CLOUD-TOP COOLING OVERNIGHT. STILL A DECENT SHOT AT THUNDERSTORMS ON MONDAY...ESPECIALLY WITH THE INCREASE IN MONDAY AND MORE FOCUS SYNOPTIC LIFT/CONVERGENCE. WITH AN INCREASING WIND FIELD AND ANOTHER DAY OF BETTER INSTABILITY...THERE IS A POTENTIAL FOR SEVERE WEATHER. MAINTAINED CHANCE WORDING...BUT TRIED TO ADD ADDITIONAL TIMING FROM NORTH TO SOUTH. TEMPS AND DEWPOINTS WILL BE A FEW DEGREES WARMER THAN TODAY. ALSO BUMPED UP WIND SPEEDS WITH THE TIGHTENING SOUTHWESTERLY GRADIENT...WHICH WILL LEAD TO LOW 80S OUT ACROSS THE THUMB AS WELL AS INLAND. LONG TERM...MONDAY NIGHT THROUGH SUNDAY EXPECT CONVECTION ON MONDAY TO CONTINUE INTO MONDAY EVENING AND DIMINISH OVERNIGHT. MODELS START TO DIFFER ON WEAR THE COLD FRONT WASHES OUT OVER LOWER MICHIGAN...WITH THE GFS...CANADIAN...EUROPEAN AND UKMET FARTHER NORTH THAN THE NAM AND LOCAL WRF. WHERE EVER THE FRONT WASHES OUT...THAT IS WHERE THE CHANCE OF THUNDERSTORMS WILL BE HIGHER ON TUESDAY AND TUESDAY NIGHT...AND FOR NOW WILL THE HIGHER CHANCE POPS FOR THE TRI CITIES AND THUMB REGION. THERE WILL BE SURFACE AND MLCAPES OF AROUND 1500 TO 2000 J/KG...WEAK SURFACE CONVERGENCE WITH THE WASHED OUT FRONT. THERE WILL BE SEVERAL WEAK IMPULSES EMBEDDED IN THE WNW FLOW OVER THE GREAT LAKES AND THE REGION WILL BE IN AREA OF DEFORMATION. THIS WILL BE ENOUGH FOR CHANCE POPS BOTH TUESDAY AND TUESDAY NIGHT...AGAIN HIGHER TO THE NORTHERN PART OF THE FORECAST AREA. SEVERE THREAT LOOKS LIMITED BY THE LACK OF A STRONG SYSTEM OR WIND FIELD. GUIDANCE TEMPS ARE IN GOOD AGREEMENT FOR THE LOWS AND DID NOT DIFFER. FOR TUESDAY HOWEVER...ETA MOS WAS MUCH LOWER GIVEN THE FARTHER SOUTH FRONTAL POSITION WITH MORE CLOUDS AND PRECIP. WENT CLOSER TO THE OLD FWC WHICH WAS A COMPROMISE WITH A LEAN TOWARD THE WARMER MAV GUIDANCE. THE NEXT MOST SOLID SHORTWAVE MOVES ACROSS THE NORTHERN LAKES ON WEDNESDAY. BOTH THE NAM AND GFS HAVE SOME ADDITIONAL CONVECTIVE ENERGY TO THE SOUTH OF THAT FOR WEDNESDAY. GIVEN THE INSTABILITY THAT WILL BE IN PLACE...WEDNESDAY COULD BE BEST CHANCE AND THE MOST WIDESPREAD COVERAGE OF THUNDERSTORMS. IN THE WAKE OF THIS SHORTWAVE...THE BOUNDARY/COLD FRONT PUSHES JUST SOUTH OF THE STATE LEAVING THE REGION IN MODEST DRY AIR AND GENERAL SUBSIDENCE. THEREFORE...WILL TAKE OUT THE CHANCE OF THUNDERSTORMS AND GO WITH A DRY FORECAST. ANOTHER SHORTWAVE AND STRONGER COLD FRONT ARE FORECAST TO MOVE INTO THE GREAT LAKES ON FRIDAY BY NEARLY ALL OF THE MODELS (EXCEPT THE LOCAL WRF...BUT 12Z RUN IS MOVING TOWARD THAT STRONGER FRIDAY COLD FRONT). WITH THE PROGGED STRENGTH AND INSTABILITY AHEAD OF THE COLD FRONT...THERE COULD BE SOME SEVERE WEATHER CHANCES ON FRIDAY. BEHIND THAT COLD FRONT...VERY DRY AND STABLE AIR IN PLACE FOR SATURDAY WITH ONLY SOME MID AND UPPER LEVEL MOISTURE FOR SUNDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING SAGINAW BAY...10 AM MONDAY TO 8 PM MONDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BRAVENDER LONG TERM....RBP AVIATION...MANN YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 323 AM EDT MON JUL 24 2006 .SHORT TERM /TODAY THROUGH WEDNESDAY/...SO FAR TONIGHT THE RADAR SCOPE HAS BEEN NEARLY CLEAR OF ACTIVITY EXCEPT FOR A STRONG CLUSTER OF STORMS JUST EAST OF BULLS BAY OFF THE CHARLESTON COUNTY COAST. SFC OBS THIS MORNING SHOW THE BL FLOW PARALLEL TO THE COAST OR SLIGHTLY OFFSHORE...WHICH YIELDS SLIGHT DRY ADVECTION. THIS WOULD EXPLAIN THE LACK OF SHOWERS OVER MOST OF THE WATERS OR ALONG OUR COAST. BOTH THE WRF AND RUC SHOW A VEERING TREND IN THE BL WINDS...MAKING FOR AN EVEN MORE OFFSHORE FETCH AND SEVERELY LIMITING SHOWER DEVELOPMENT FOR THE REMAINDER OF THE NIGHT. A QUASI-STATIONARY FRONTAL BOUNDARY REMAINS ACROSS UPSTATE SC AND CENTRAL NC. NOW THAT THE MAIN UPPER LEVEL TROUGH HAS PULLED OFF TO THE NORTHEAST...THIS FRONT HAS MISSED ITS CHANCE OF PUSHING THROUGH THE CWFA. THEREFORE...IT SHOULD GENERALLY REMAIN FAR ENOUGH NORTHWEST OF OUR AREA TO REDUCE OR ELIMINATE ANY DIRECT EFFECTS. A WEAKER SHORTWAVE IS CURRENTLY DIGGING ACROSS THE LOWER MISSISSIPPI VALLEY...WITH A LARGE SHIELD OF ASSOCIATED MID AND HIGH LEVEL CLOUDINESS SEEN ON IR SATELLITE IMAGERY ACROSS THE SOUTHEAST U.S. THIS FEATURE IS EXPECTED TO DEAMPLIFY TODAY...LESSENING THE PVA IN OUR AREA. ALSO...THE SIGNIFICANT CLOUD SHIELD SHOULD TEND TO LIMIT INSOLATION AND INSTABILITY. HOWEVER...POCKETS OF STRONG HEATING WILL PROBABLY OCCUR...LIKELY RESULTING IN THE FIRST SHOWERS OR STORMS OF THE DAY. THE BEST CHANCE OF PARTIAL CLEARING LOOKS TO BE ACROSS SOUTHEAST GEORGIA DUE TO SOME WEAK NVA AND SUBSIDENCE. BL MOISTURE SHOULD MIX OUT A LITTLE MORE IN THIS AREA AS WELL...DUE TO A WESTERLY FLOW FOR THE FIRST HALF OF THE AFTERNOON. WILL START THE DAY WITH SLIGHT CHANCE OF SHOWERS AND STORMS...THEN SLOWLY RAMP UP TO CHANCE FOR THE FIRST HALF OF THE AFTERNOON AND LIKELY ALL TERRESTRIAL LOCATIONS FOR THE LATE AFTERNOON INTO THE EARLY EVENING. MUCH LIKE YESTERDAY...SEVERE WX PARAMETERS ARE EXPECTED TO REMAIN MARGINAL DUE TO MEDIOCRE SFC HEATING AND NO REAL MID-LEVEL COLD POOL. ALSO...H7 FLOW SHOULD ONLY BE ABOUT 10 KTS WHICH WILL LIMIT THE ABILITY OF STORMS TO ORGANIZE. THEREFORE...WILL NOT ISSUE A SEVERE WX OUTLOOK OR INCLUDE SEVERE WORDING IN ZONES. LATEST DAY 1 CONVECTIVE OUTLOOK FROM SPC ALSO CONFIRMS THIS ASSESSMENT...WITH NO RISK AREAS COVERING OUR CWA. NUDGED HIGH TEMPS UP A FEW DEGREES ABOVE MOS ACROSS SOUTHEAST GEORGIA TODAY. THE LAST TWO DAYS ALL MOS BULLETINS HAVE BEEN SIGNIFICANTLY TOO LOW IN THIS AREA. WRF HINTS AT A PERIOD OF WESTERLY SFC FLOW INTO THIS AREA WITH SOME DRIER AIR MIXING DOWN...WHICH WHEN COMBINED WITH POCKETS OF SUN SHOULD YIELD TEMPS IN THE LOWER TO MIDDLE 90S. CONVECTION IS EXPECTED TO TAPER OFF PRETTY QUICKLY TONIGHT WITH THE LOSS OF DAYTIME HEATING. THEREFORE WENT WITH ONLY A SLIGHT CHANCE FOR THE OVERNIGHT HOURS. AS THE SHORTWAVE TROUGH FLATTENS OUT ON TUE...A NEARLY ZONAL UPPER FLOW IS EXPECTED. WITH WESTERLY FLOW IN MOST OF THE LOWER 500 MB...LAPSE RATES SHOULD REMAIN PRETTY WEAK. SOME WEAK SHORTWAVE ENERGY MAY AFFECT THE SC AREAS ASSUMING THE WRF PROG IS CORRECT. PLAN ON ONLY A CHANCE OF SHOWERS AND STORMS ON TUE. TEMPS COULD AGAIN BE PRETTY WARM ACROSS OUR WRN ZONES DUE TO CONSIDERABLE SUN AND WLY FLOW. HAVE BUMPED HIGHS A DEGREE OR TWO ABOVE MOS NUMBERS. POPS DIMINISH EVEN FURTHER FOR WED DUE TO WEAK UPPER RIDGING OVER THE SOUTHEAST. WILL CARRY 30 POP OVER LAND AREAS WITH 20S OVER THE WATERS. TEMPS AGAIN A DEGREE OR TWO ABOVE NORMAL. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...BERMUDA HIGH PRESSURE LOOKS TO REBUILD ACROSS THE WESTERN ATLC AND MOST OF THE CWFA LATE IN THE WEEK. THIS SHOULD RESULT IN A RETURN TO TYPICAL DIURNAL CONVECTION AND TEMPS NEAR NORMAL. && .AVIATION...VFR CONDITIONS WL PREVAIL THROUGH THE MRNG HRS...AFT WHICH NUMEROUS TSTMS ARE XPCTD TO DVLP ACROSS THE RGN. THE SEA BREEZE WL MEANDER THROUGH THE KSAV AND KCHS TERMINALS BY MID AFTN AND WL PROVIDE A FOCUS FOR TSTM DVLPMNT SIMILAR TO WHAT TRANSPIRED YDA AFTN/EVNG. UNFORTUNATELY THE 00Z SHORT TERM MODEL GUIDANCE IS PROVING TO BE USELESS IN DETERMINING POSSIBLE TSTM IMPACTS AT EITHER TERMINAL TDA. WE HAVE THEREFORE OPTED TO KEEP MENTION OF TSTMS OUT OF THE TAFS FOR NOW AND JUST GO WITH MENTIONS OF CB/S AND VCTS FOR NOW. HOPEFULLY THE 06Z AND 12Z MODEL RUNS WL CONVERGE ON A MORE CLR CUT CONVECTIVE SOLN LTR THIS MRNG. && .MARINE...A WELL DEFINED LAND BREEZE IS NOTED ALONG LWR SC COAST THIS MRNG...ROUGHLY FROM HUNTING ISLAND TO ABOUT 8 NM E OF CAPE ROMAIN. AHEAD OF THE LAND BREEZE A STRONG NOCTURNAL SURGE IS IN PROGRESS WITH WNDS SOLIDLY IN THE 15-20 KT RANGE...WHILE BEHIND IT WNDS HAVE BECOME WLY 10-15 KT. THE BNDRY HAS SHOWN LTL MOVEMENT OVR THE PAST FEW HRS PER MESONET AND CARO-COOP OBSERVATIONS SO XPCT WINDY AND CHOPPY CONDITIONS TO PREVAIL ACROSS MOST OF THE MARINE AREA THROUGH SUNRISE...AFT WHICH WNDS WL QUICKLY DIMINISH. WNDS WL BACK MORE SLY THIS AFTN WITH THE DVLPMNT OF ANOTHER ROBUST SEA BREEZE. FCST SOUNDINGS AND 24/00Z MMG GUIDANCE SUGGEST WNDS ALONG THE COAST AND IN THE CHARLESTON HARBOR WL NOT BE QUITE A STRONG AS PREVIOUS DAYS. ATLC HIGH PRES WL REMAIN ANCHORED WELL TO THE E OF THE RGN FOR THE REMAINDER OF THE WEEK WHICH WL KEEP A SLY FLOW REGIME IN PLACE. DIURNAL SURGES CAN BE XPCTD THROUGH THE PERIOD. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ JRL/ST sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1210 PM EDT MON JUL 24 2006 .UPDATE... KIWX RADAR WAS SHOWING SCATTERED SHOWERS AND THUNDERSTORMS ACRS SOUTHERN LAKE MICHIGAN EARLY THIS AFTERNOON. THESE SHOWERS AND THUNDERSTORMS WERE IN ASSOCIATED WITH AN UPR LVL S/WV THAT STRETCHED FROM NRN LOWER MICHIGAN SOUTHWEST INTO SRN WISCONSIN. THIS S/WV WILL SLOWLY MOVE SE INTO THE FCST AREA THROUGH THIS EVENING. HAVE INTRODUCED A 30 PERCENT CHC OF SHOWERS AND THUNDERSTORMS ACRS SOUTHWEST LOWER MICHIGAN AND FAR NORTHWEST INDIANA TO ACCOUNT FOR THE POSSIBILITY OF PCPN IN THESE AREAS AS THEY WILL BE THE MOST LIKELY REGION TO SEE SOME ACTIVITY THIS AFTN AND EVENING. WILL INTERROGATE MODEL DATA AND OBSERVATIONAL TRENDS TO SEE IF THE AREA HAS TO BE EXPANDED AND/OR EXTENDED IN TIME BEYOND THIS EVENING WITH THE AFTN FCST PACKAGE. CURRENT FCST TEMPS ARE STILL ON TRACK...SO NO CHANGES NEEDED. && .PREV DISCUSSION... AVIATION... VFR CONDITIONS WILL PREVAIL WITH CONVECTION EXPECTED TO REMAIN NORTH OF BOTH SITES. WINDS STILL EXPECTED TO PICK UP WITH A FEW GUSTS IN THE 20 TO 25 KT RANGE POSSIBLE DURING THE AFTERNOON. SKY COVER WILL BE LIMITED TO SOME DIURNAL CU AS WELL AS PASSING MID/HIGH CLOUDS. . SHORT TERM... TODAY AND TONIGHT. RIDGE AXIS HAS NOW SHIFTED EAST OF THE FORECAST AREA...ALLOWING WAA TO BEGIN. 850 MB TEMPS WILL CLIMB INTO THE UPPER TEENS BY AFTERNOON. THIS COMBINED WITH WHAT SHOULD BE A GOOD DEAL OF SUNSHINE...AT LEAST TO START WITH...WILL ALLOW TEMPS TO CLIMB BACK TO NORMAL OR EVEN SLIGHTLY ABOVE NORMAL LEVELS TODAY. DEWPTS WILL ALSO BE ON THE INCREASE WITH READINGS IN THE LOW TO MID 60S COMMON UPSTREAM. FRONTAL BOUNDARY MAKING SLOW PROGRESS SOUTH FROM MINNESOTA AND LK SUPERIOR. LINE OF SHOWERS AND STORMS IN ADVANCE OF THIS DIVING SOUTH AND EAST INTO NORTHERN LWR MI...POSING NO CONCERN. A SMALL LINE OF SHOWERS AND STORMS HAS DEVELOPED OVER THE PAST HOUR EAST OF LACROSSE WISCONSIN. PROFILER DATA IS MISSING AT THIS TIME...BUT RUC SHOWS A 30+KT LLJ FEEDING INTO THIS AREA WITH INCREASING LOW LEVEL THETA-E. TRENDS AND 850-300 MB THICKNESS PLOTS SHOW THIS ACTIVITY SHOULD ALSO DRIFT INTO MICHIGAN AND POSE NO THREAT. WILL NEED TO MONITOR TRENDS TO MAKE SURE BUT WILL MAINTAIN A DRY FORECAST TODAY. CU RULE SHOWS DIURNAL DEVELOPMENT ONCE AGAIN...BUT VALUES NOT AS HIGH AS YESTERDAY. ALSO WITH INCREASING SFC WINDS AS GRADIENT INCREASES AND STRONGER WIND FLOW IS MIXED DOWN SOMEWHAT...LAKE BREEZE DEVELOPMENT UNLIKELY. SCT CU WILL DEVELOP ONCE AGAIN...BUT CU RULE SHOWING NOT AS MUCH COVERAGE AS TODAY. FOCUS BEGINS TO TURN TONIGHT ONTO ABOVE MENTIONED FRONTAL BOUNDARY ACROSS LWR MI THAT WILL BE MAKING SLOW PROGRESS SOUTH. COMPLEX OF STORMS EXPECTED TO DEVELOP AND MOVE ALONG IT TONIGHT. TRACK OF THIS SHOULD REMAIN FAR ENOUGH NORTH TO ALLOW CONTINUED DRY FORECAST TONIGHT. WITH CONTINUED WAA AND INCREASING MSTR LOWS WILL BE A GOOD 10 DEGREE WARMER IN MANY LOCATIONS TONIGHT...DROPPING ONLY TO THE MID TO UPPER 60S. LONG TERM... TUESDAY THROUGH SUNDAY. NOT QUITE READY TO THROW LATEST NAM OUT THE WINDOW. SHORTWAVE ENERGY OVER NORTHEAST MT SHOULD CONTINUE TO DAMPEN AS LONGWAVE TROF ACROSS EASTERN STATES DEAMPLIFIES AS NEW ENGLAND WAVE LIFTS NORTHEAST AND GREAT BASIN HIGH SLOWLY WEAKENS AND PUSHES SOUTH WHERE NAM HAS SHOWN RUN TO RUN CONSISTENCY HERE. GFS AND NAM WITH HUGE DISPARITIES WITH REGARDS TO MOS POPS TUESDAY NIGHT...CATEGORICAL VS. LT 20. TUE NIGHT MCS GENERATION PER GFS A BIT SUSPECT WITH CONVECTIVE SCALE FEEDBACK. PREFERENCE LIES TOWARD CONSISTENCY AND NAM AND AWAIT MORE STRONGER ENERGY OVER NORTHWEST TERRITORIES TO DIVE SOUTHEAST INTO CENTRAL CANADA/UPPER PLAINS BY MIDWEEK. DEEP MOIST TRANSPORT AHEAD OF SYSTEM WITH PWAT INCREASING TO NEAR 2 INCHES AND ARRIVAL OF BETTER KINEMATICS/INSTABILITY LATE WEDNESDAY AFTERNOON WITH POTENTIAL MCS DEVELOPMENT UPSTREAM TO MOVE ESE THROUGH SOUTHERN GREAT LAKES WED NIGHT....HAVE RAISED TSRA POPS TO HIGH CHANCE RANGE WED NIGHT AND THROUGH THU FOR POTENTIAL AIRMASS DESTABILIZATION AND LOW LEVEL VEERING AHEAD OF APPROACHING MID LEVEL WAVE THU. NO OTHER CHANGES REMAINDER OF FORECAST. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...HICKMAN AVIATION/SHORT TERM...FISHER LONG TERM....MURPHY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 725 AM EDT MON JUL 24 2006 .AVIATION... VFR CONDITIONS WILL PREVAIL WITH CONVECTION EXPECTED TO REMAIN NORTH OF BOTH SITES. WINDS STILL EXPECTED TO PICK UP WITH A FEW GUSTS IN THE 20 TO 25 KT RANGE POSSIBLE DURING THE AFTERNOON. SKY COVER WILL BE LIMITED TO SOME DIURNAL CU AS WELL AS PASSING MID/HIGH CLOUDS. && .PREV DISCUSSION... SHORT TERM... TODAY AND TONIGHT. RIDGE AXIS HAS NOW SHIFTED EAST OF THE FORECAST AREA...ALLOWING WAA TO BEGIN. 850 MB TEMPS WILL CLIMB INTO THE UPPER TEENS BY AFTERNOON. THIS COMBINED WITH WHAT SHOULD BE A GOOD DEAL OF SUNSHINE...AT LEAST TO START WITH...WILL ALLOW TEMPS TO CLIMB BACK TO NORMAL OR EVEN SLIGHTLY ABOVE NORMAL LEVELS TODAY. DEWPTS WILL ALSO BE ON THE INCREASE WITH READINGS IN THE LOW TO MID 60S COMMON UPSTREAM. FRONTAL BOUNDARY MAKING SLOW PROGRESS SOUTH FROM MINNESOTA AND LK SUPERIOR. LINE OF SHOWERS AND STORMS IN ADVANCE OF THIS DIVING SOUTH AND EAST INTO NORTHERN LWR MI...POSING NO CONCERN. A SMALL LINE OF SHOWERS AND STORMS HAS DEVELOPED OVER THE PAST HOUR EAST OF LACROSSE WISCONSIN. PROFILER DATA IS MISSING AT THIS TIME...BUT RUC SHOWS A 30+KT LLJ FEEDING INTO THIS AREA WITH INCREASING LOW LEVEL THETA-E. TRENDS AND 850-300 MB THICKNESS PLOTS SHOW THIS ACTIVITY SHOULD ALSO DRIFT INTO MICHIGAN AND POSE NO THREAT. WILL NEED TO MONITOR TRENDS TO MAKE SURE BUT WILL MAINTAIN A DRY FORECAST TODAY. CU RULE SHOWS DIURNAL DEVELOPMENT ONCE AGAIN...BUT VALUES NOT AS HIGH AS YESTERDAY. ALSO WITH INCREASING SFC WINDS AS GRADIENT INCREASES AND STRONGER WIND FLOW IS MIXED DOWN SOMEWHAT...LAKE BREEZE DEVELOPMENT UNLIKELY. SCT CU WILL DEVELOP ONCE AGAIN...BUT CU RULE SHOWING NOT AS MUCH COVERAGE AS TODAY. FOCUS BEGINS TO TURN TONIGHT ONTO ABOVE MENTIONED FRONTAL BOUNDARY ACROSS LWR MI THAT WILL BE MAKING SLOW PROGRESS SOUTH. COMPLEX OF STORMS EXPECTED TO DEVELOP AND MOVE ALONG IT TONIGHT. TRACK OF THIS SHOULD REMAIN FAR ENOUGH NORTH TO ALLOW CONTINUED DRY FORECAST TONIGHT. WITH CONTINUED WAA AND INCREASING MSTR LOWS WILL BE A GOOD 10 DEGREE WARMER IN MANY LOCATIONS TONIGHT...DROPPING ONLY TO THE MID TO UPPER 60S. LONG TERM... TUESDAY THROUGH SUNDAY. NOT QUITE READY TO THROW LATEST NAM OUT THE WINDOW. SHORTWAVE ENERGY OVER NORTHEAST MT SHOULD CONTINUE TO DAMPEN AS LONGWAVE TROF ACROSS EASTERN STATES DEAMPLIFIES AS NEW ENGLAND WAVE LIFTS NORTHEAST AND GREAT BASIN HIGH SLOWLY WEAKENS AND PUSHES SOUTH WHERE NAM HAS SHOWN RUN TO RUN CONSISTENCY HERE. GFS AND NAM WITH HUGE DISPARITIES WITH REGARDS TO MOS POPS TUESDAY NIGHT...CATEGORICAL VS. LT 20. TUE NIGHT MCS GENERATION PER GFS A BIT SUSPECT WITH CONVECTIVE SCALE FEEDBACK. PREFERENCE LIES TOWARD CONSISTENCY AND NAM AND AWAIT MORE STRONGER ENERGY OVER NORTHWEST TERRITORIES TO DIVE SOUTHEAST INTO CENTRAL CANADA/UPPER PLAINS BY MIDWEEK. DEEP MOIST TRANSPORT AHEAD OF SYSTEM WITH PWAT INCREASING TO NEAR 2 INCHES AND ARRIVAL OF BETTER KINEMATICS/INSTABILITY LATE WEDNESDAY AFTERNOON WITH POTENTIAL MCS DEVELOPMENT UPSTREAM TO MOVE ESE THROUGH SOUTHERN GREAT LAKES WED NIGHT....HAVE RAISED TSRA POPS TO HIGH CHANCE RANGE WED NIGHT AND THROUGH THU FOR POTENTIAL AIRMASS DESTABILIZATION AND LOW LEVEL VEERING AHEAD OF APPROACHING MID LEVEL WAVE THU. NO OTHER CHANGES REMAINDER OF FORECAST. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ AVIATION/SHORT TERM...FISHER LONG TERM....MURPHY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 1022 AM EDT MON JUL 24 2006 .DISCUSSION... UPDATED THE FORECAST TO ADD ISOLATED SHOWERS AND THUNDERSTORMS OVER OUR SOUTHERN AND EASTERN CWA. RUC...WRF AND GFS ARE SHOWING AN AREA OF INCREASED MEAN RH AND OMEGA MOVING NORTHWARD FROM ERN TENNESSEE. THIS APPEARS TO BE ASSOCIATED WITH A WEAK INVERTED SURFACE TROF OVER ERN TENNESSEE INDICATED ON THE 13Z SURFACE ANALYSIS. MORNING SOUNDINGS SHOW A WEAK MID LEVEL CAP IN PLACE...BUT MODEL SOUNDINGS SHOW THIS CAP WEAKENING LATER THIS AFTERNOON OVER THE SRN AND SE PORTIONS OF THE CWA. THIS SHOULD LEAD TO AT LEAST ISOLATED CONVECTION FIRING. CONVECTIVE TEMPS SHOULD LOWER INTO THE UPPER 70S IN SOME AREAS...WITH MID 80S REMAINING IN THE CENTRAL AND NRN PORTION OF THE CWA WHERE THE CAP REMAINS A LITTLE STRONGER. ALSO LOWERED TEMPS A FEW DEGREES...ESPECIALLY WHERE THE CONVECTION IS EXPECTED TO FIRE. ALSO INCREASED CLOUD COVER AND MENTIONED PARTLY CLOUDY IN OUR ENTIRE CWA...WITH CU DEVELOPING IN THE LATE MORNING AND AFTERNOON. UPDATED TEXT AND GRAPHICAL FORECASTS HAVE BEEN SENT. && .PREV DISCUSSION... 300 AM EDT MON JUL 24 2006 DISCUSSION... HIGH PRESSURE STILL FIRMLY IN CONTROL OF WEATHER ACROSS FORECAST AREA. 0Z 500 AND 850 HPA CHART ANALYSIS SHOW RIDGING ALSO IN PLACE AT MIDLEVELS...WITH LARGE AREA OF 500 HPA HIGH PRESSURE IN PLACE OVER WESTERN UNITED STATES...WHICH SHOULD PUSH EASTERN TROUGH OUT OF THE STATES IN THE NEXT DAY OR SO. CURRENT WATER VAPOR AND IR SATELLITE IMAGERY INDICATING THAT A LARGE AMOUNT OF DRY AIR IS CURRENTLY IN PLACE ACROSS MUCH OF THE MIDWEST. WITH THIS IN MIND...AND WITH NO STRONG SYSTEM TO PUSH HIGH PRESSURE OUT OF AREA...ANTICIPATE A DRY FORECAST ONCE AGAIN THROUGH MIDWEEK THIS WEEK. WENT WITH GFS SOLUTION ONCE AGAIN FOR CONSISTENCY. MADE A FEW MINOR TWEAKS TO CLOUD COVER FORECAST...GENERALLY DECREASING CLOUD COVER THROUGH WEDNESDAY...WITH A GRADUAL INCREASE IN CLOUD COVER TO MOSTLY CLOUDY FOR WEDNESDAY NIGHT INTO THURSDAY. MODELS INDICATING THAT STRONG LOW LEVEL JET WILL DEVELOP AND MOVE INTO THE AREA FROM THE SOUTHWEST WEDNESDAY NIGHT. AT THIS TIME MODELS ARE NOT MOVING ANY ORGANIZED WEATHER SYSTEMS ACROSS THE EASTER HALF OF THE UNITED STATES WEDNESDAY NIGHT...SO DECIDED TO REMOVE POPS FROM FORECAST THROUGH EARLY THURSDAY. IT APPEARS THAT THE INGREDIENTS FOR PRECIPITATION WONT FULLY COME TOGETHER UNTIL THURSDAY AFTERNOON. WINDS WERE TWEAKED SLIGHTLY ALSO TO REFLECT CURRENT MODEL OUTPUT...WITH A PERSISTENT SOUTH TO SOUTHWEST WIND DIRECTION ANTICIPATED AT THIS TIME THROUGH DAY 3. DEWPOINTS LOOKED GOOD AND WERE UNCHANGED. ADJUSTMENTS WERE ALSO MADE TO WEATHER AND QPF GRIDS TO REFLECT CHANGES MADE TO POP GRIDS. STILL LEAVING IN MENTION OF VALLEY FOG FOR TONIGHT AND TUESDAY NIGHT. 900 PM EDT SUN JUL 23 2006 HIGH PRESSURE IS FIRMLY IN CONTROL THIS EVENING WITH THE AFTERNOON CU FIELD NOW LARGELY DISSIPATED. SKIES SHOULD REMAIN CLEAR OVERNIGHT... EXCEPT WHERE FOG AND STRATUS FORM TOWARD DAWN. ONLY POINT OF CONTENTION WITH THE INHERITED FORECAST IS MIN TEMPS TONIGHT. BELIEVE WE/LL BE ABLE TO DROP A LITTLE LOWER THAN OBSERVED LAST NIGHT WITH BETTER RADIATIONAL COOLING CONDITIONS...I.E. LESS CLOUD COVER AND SLIGHTLY LOWER SURFACE DEWPOINTS. FULLY EXPECT A FEW MID 50S IN THE MORE SHELTERED VALLEY LOCATIONS AND WILL ADJUST MIN TEMP GRID TO REFLECT THIS. MAJORITY OF LOCATIONS WILL SETTLE AROUND 60 HOWEVER...SO WILL ELECT NOT TO UPDATE THE ZONES AT THIS TIME. 327 PM EDT SUN JUL 23 2006 SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT... CU THAT DEVELOPED THIS AFTERNOON WILL BEGIN TO DISSIPATE LATE THIS AFTERNOON AND EVENING. LOOKING OUTSIDE HERE AT JKL...THE CU HAS ALREADY BEGUN TO SHOW LESS VERTICAL DEVELOPMENT THAN EARLIER IN THE AFTERNOON. WILL GO WITH MOSTLY CLEAR SKIES OVERNIGHT WITH HIGH PRESSURE OVER THE AREA. IT WILL BE COOLER THAN IT HAS BEEN FOR A WHILE WITH OVERNIGHT LOWS IN THE UPPER 50S TO LOWER 60S. DRY AIR MIXING DOWN THIS AFTERNOON HAS LEAD TO DEW POINTS IN THE UPPER 50S TO LOWER 60S. BELIEVE WITH GOOD RADIATIONAL COOLING OVERNIGHT WE WILL BE ABLE TO REACH THESE TEMPS. WILL ALSO MENTION AREAS OF VALLEY FOG DEVELOPING TONIGHT INTO EARLY TOMORROW MORNING. FOR MONDAY NGM...WRF AND GFS ARE SHOWING HIGH PRESSURE CENTERED JUST EAST OF KENTUCKY. CONVECTIVE TEMPS ARE IN THE UPPER 80S...AND MODEL SOUNDINGS SHOW A GOOD MID LEVEL CAP. THIS SHOULD ALLOW FOR ONLY A FEW CU TO DEVELOP DURING THE DAY. MIXING DOWN 850 MB TEMPS...HIGHS SHOULD BE IN THE MID TO UPPER 80S. THIS MATCHES CLOSELY WITH MOS. MONDAY NIGHT A SURFACE WAVE MOVES ACROSS GEORGIA TO SOUTH CAROLINA. THIS COULD SPREAD A FEW MORE CLOUDS ACROSS THE SOUTHERN PORTION OF OUR CWA...BUT NO PRECIP IS EXPECTED. TUESDAY THE SURFACE WAVE CONTINUES MOVING NE ALONG THE US COAST. A WEAK H5 TROF WILL ALSO SWING THROUGH THE AREA. GFS APPEARS A LITTLE STRONGER THAN THE OTHER MODELS WITH THE ASSOCIATED VORT MAX MOVING ACROSS THE AREA. I AM SIDING MORE WITH THE WRF ATTM. CONSIDERED PUTTING IN A SLIGHT CHANCE FOR PRECIP...BUT FEEL THERE IS NOT QUITE ENOUGH SUPPORT FOR SHOWER OR THUNDERSTORM DEVELOPMENT OVER EASTERN KENTUCKY. MIXING DOWN 850 MB TEMPS...HIGHS SHOULD BE IN THE MID 80S TO AROUND 90. TUESDAY NIGHT THE UPPER TROUGH SHOULD BE EAST OF THE AREA. IT SHOULD REMAIN DRY. LOW TEMPS WILL SEE A WARMING TREND THROUGHOUT THE SHORT TERM PERIOD AS MORE MOISTURE BEGINS TO ADVECT IN. MY LOW TEMP FORECAST CAME OUT CLOSE TO MOS GUIDANCE. LONG TERM...WEDNESDAY THROUGH SUNDAY... THE MODELS ARE IN PRETTY GOOD AGREEMENT. THE GENERAL PATTERN IS THE SAME...THE BIGGEST DIFFERENCES ARE IN THE TIMING AND RELATIVE STRENGTH OF SHORT WAVES. THE ECMWF WAS A BIT STRONGER AND FASTER WITH A SHORT WAVE ON THURSDAY NIGHT. THE GFS WAS CONSIDERED THE MODEL OF THE DAY FOR THE EXTENDED FORECAST. THE UPPER TROUGH OVER THE AREA WILL BE MOVING OFF TO THE NORTHEAST LEAVING A MORE ZONAL UPPER LEVEL FLOW PATTERN OVER THE AREA WITH TRANSITORY SHORT WAVES. AT THE SURFACE...THE BERMUDA HIGH WILL BUILD BACK INTO THE SOUTHEAST ALLOW FOR A RETURN OF GULF MOISTURE. THIS WILL HILL TO SPARK SOME ISOLATED TO SCATTERED...MOSTLY AFTERNOON...SHOWERS AND THUNDERSTORMS ACROSS THE REGION FROM WEDNESDAY THROUGH SUNDAY. THE TEMPERATURES AND HUMIDITIES SHOULD BOTH RISE AS WARM MOIST GULF AIR WILL ONCE AGAIN BE MOVING INTO THE AREA. THE HIGH TEMPERATURES ARE EXPECTED TO STAY MOSTLY IN THE MID 80S THROUGH THE PERIOD. JUST TWEAKED THE MOS A DEGREE OR TWO. NO HUGE DIFFERENCES. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WJM ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 1021 AM CDT MON JUL 24 2006 .UPDATE... OLD FRONTAL BOUNDARY HAS BEGUN ITS SLOW RETURN NORTHWARD WITH DEWPOINTS RETURNING TO THE LOWER 70S ACROSS DEEP EAST TEXAS. CONVECTION THUS FAR HAS BEEN CONFINED TO SE TX/SW LA BUT ISOLATED CONVECTION HAS JUST RECENTLY DEVELOPED FURTHER NORTH INTO CLL AND PSN WITH THE RETURNING FRONT. CURRENT FCST HAS LOW POPS INTO N LA BY THIS AFTERNOON...THIS MAY BE A LITTLE TOO FAR NORTH AS PWATS CURRENTLY RUNNING ONLY 1.25 ON THIS MORNINGS 12Z RAOB. WILL NOT CHANGE AS THE MOISTURE IS RETURNING QUICKLY FROM THE SOUTH...BUT HAVE ADDED SLIGHT CHANCE POPS FURTHER WEST TO ENCOMPASS THE I-20 CORRIDOR OF NE TX AS THIS REGION IS BETTER CO-LOCATED WITH 850MB THETAE AXIS DEPICTED WELL BY LATEST RUC40 PROG. ALSO ADJUSTED CLOUD COVER SOMEWHAT DOWN SOUTH AS MID AND HIGH CLOUD DECK QUICKLY RETURNING NORTHWARD. TEMPS IN GOOD SHAPE SO MADE NO CHANGES ATTM. UPDATE OUT SHORTLY...13. && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 13 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1110 AM EDT MON JUL 24 2006 .UPDATE... WEAK SHRTWV AND BAND OF 300K-305K ISENTROPIC LIFT THAT SUPPORTED AREA OF SHRA/TSRA OVER CNTRL UPR MI AND NRN LK MI HAS MOVED E OF UPR MI. HOWEVER ADDITIONAL SHRA AND WEAKER ISOLD TSRA HAD DEVELOPED ALONG AND AHEAD OF A SFC FRONT/TROF FROM NRN LK SUPERIOR INTO W UPR MI AND NW WI. EXPECT THAT THE COMBINATION OF THE FRONT ALONG WITH CONTRIBUTIONS FROM LK BREEZE BOUNDARIES AND SFC HEATING WILL PROVIDE ADDITIONAL SUPPORT FOR SHRA/TSRA THIS AFTERNOON. SO...BEST CHANCES FOR TSTMS WILL BE MAINLY SOUTH OF A LINE FROM MQT-WATERSMEET LINE. MODIFIED FCST SNDGS AND WITH TEMPS INTO THE MID 80S AND DEWPOINTS IN THE MID 60S GIVE SBCAPE VALUES BTWN 1500-2500 J/KG. 0-6KM WIND SHEAR VALUES AROUND 35 KT WILL BE ENOUGH TO AID STORM ORGANIZATION. ALTHOUGH FREEZING LEVELS ARE FCST NEAR 14.5K FT...WET-BULB ZERO VALUES NEAR 10.5K FT WILL BE MORE FAVORABLE FOR HAIL DEVELOPMENT. IN ADDITION...SFC-H7 THETA-E DIFFERENCE NEAR 30C WILL COULD ALSO PROMOTE STRONG/SVR WINDS WITH ANY STRONGER STORMS THAT DEVELOP. && .PREV DISCUSSION...ISSUED AT 343 AM EDT MON JUL 24 2006 THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT. WATER VAPOR IMAGERY AND RUC SHOWING A LONGWAVE TROUGH OVER THE EASTERN AND SOUTHERN CONUS...A CLOSED LOW OVER NORTHEAST MANITOBA... AND LARGE RIDGE OVER THE SOUTHERN ROCKIES. A WEAK SHORTWAVE SLIDING DOWN THE LEE OF THE ROCKIES RIDGE IS PASSING THROUGH THE WESTERN U.P. ANOTHER WEAK SHORTWAVE IS MOVING THROUGH THE NORTHERN PART OF THE RIDGE AND IS OVER MONTANA. SURFACE ANALYSIS DEPICTS A LOW OVER NORTHERN ONTARIO IN CONJUNCTION WITH THE UPPER LEVEL LOW. A COLD FRONT DRAPED FROM THIS LOW IS OVER NORTHWEST MINNESOTA...NORTH DAKOTA...AND NORTHEAST MONTANA THIS MORNING. A 1009MB HIGH IS PUSHING THIS FRONTAL SYSTEM SOUTH. THE MID LEVEL LOW WILL SLIDE INTO NORTHERN ONTARIO. A SHORTWAVE WRAPPING AROUND THE BASE OF THIS LOW WILL SWEEP INTO CENTRAL ONTARIO. THE WEAK SHORTWAVE OVER WESTERN U.P. WILL SWEEP ACROSS THE REST OF THE FORECAST AREA BY 18Z. ANOTHER SHORTWAVE WILL BE TO THE SOUTHWEST OF THE FORECAST AREA. THE COLD FRONT WILL REACH LAKE SUPERIOR BY SUNRISE...AND WILL PASS THROUGH THE AREA DURING THE DAY. THE HIGH OVER CANADA WILL START TO BUILD INTO NORTH DAKOTA. 850-500MB Q-VECTOR CONVERGENCE WILL BE STRONGEST THIS MORNING OVER THE CENTRAL U.P. THIS WILL SLIDE INTO NORTHERN LAKE MICHIGAN BY NOON. MUCAPE WILL BE AROUND 800J/KG OVER NORTHERN WISCONSIN WITH LOWER AMOUNTS MOVING THROUGH THE U.P. AN 850MB THETA-E RIDGE WILL EXTEND FROM NORTHERN WISCONSIN THROUGH CENTRAL U.P. BY SUNRISE AND THROUGH NORTHERN LAKE MICHIGAN BY LATE AFTERNOON. 300K ISENTROPIC ANALYSIS INDICATE STRONG ASCENT AHEAD OF THE FRONT OVER THE FORECAST AREA THIS MORNING. BY 18Z MOST OF THE ASCENT WILL BE GONE AS THE FRONT MOVES INTO NORTHERN LAKE MICHIGAN. THUS IT LOOKS AS IF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ESPECIALLY OVER THE SOUTHERN U.P. AND OVER THE NORTHERN LAKE SUPERIOR TODAY. A SOUTHWEST FLOW AHEAD OF THE FRONT WILL HELP TO PUSH TEMPERATURES UP AS TEMPERATURES OVER WISCONSIN REMAINED IN THE LOW 70S THIS MORNING. THE TEMPERATURES WILL RISE INTO THE MID 80S BY LATE AFTERNOON AND START TO FALL OFF AFTER THE FRONT SWEEPS THROUGH. ANOTHER WEAK SHORTWAVE WILL SWEEP INTO WESTERN U.P. TONIGHT. A SURFACE LOW WILL DEVELOP OVER CENTRAL CANADA AND MOVE TO NORTHEAST MANITOBA. DRIER AIR WILL MOVE OVER THE NORTHERN PART OF THE FORECAST AREA. HIGHER SURFACE-500MB RH WILL BE OVER NORTHERN WISCONSIN...AND SOUTHERN U.P. MUCAPE ANALYSIS INDICATE THAT THERE WILL BE VALUES AROUND 1000J/KG ALONG THE WISCONSIN BORDER AND OVER THE SOUTHERN U.P. WILL LEAVE A CHANCE OF SHOWERS AND THUNDERSTORMS FOR TONIGHT IN THOSE AREAS. THE WEAK SHORTWAVE WILL SLIDE INTO EASTERN LAKE SUPERIOR ON TUESDAY. MEANWHILE...ANOTHER SHORTWAVE WILL DEVELOP OVER CENTRAL CANADA AND MOVE INTO ONTARIO JUST NORTHWEST OF LAKE SUPERIOR. A WEAK CLOSED LOW IS EXPECT TO DEVELOP OVER WISCONSIN. CAPE VALUES WILL REACH 1300-1700J/KG ACROSS THE U.P. JUST NORTHEAST OF THIS LOW. AN 850MB THETA-E RIDGE WILL BECOME FOCUSED ACROSS THE U.P. FROM WEST TO EAST AS WILL THE HIGHEST RH. A SURFACE LOW WILL DEVELOP OVER SOUTH CENTRAL CANADA AND MOVE INTO NORTHERN MINNESOTA. ISENTROPIC ASCENT WILL INCREASE AHEAD OF THIS LOW. THUS WILL KEEP THUNDERSTORMS POSSIBLE THROUGH TUESDAY. AS THE WISCONSIN SHORTWAVE MOVES EAST ACROSS THE SOUTHERN U.P. TUESDAY NIGHT...ANOTHER SHORTWAVE WILL SWEEP ACROSS THE NORTH PART OF THE FORECAST AREA AS AN EVEN DEEPER SHORTWAVE WILL SWING INTO WESTERN LAKE SUPERIOR. THE SURFACE LOW WILL MOVE OUT OF MINNESOTA INTO NORTHWEST WISCONSIN. THE MEAN SURFACE-500MB RH AND ASSOCIATED 850MB THETA-E RIDGE WILL SLIDE INTO WESTERN U.P. AS ANOTHER LEAVES THE AREA. A SERIES OF WEAK SHORTWAVE WILL SLIDE THROUGH THE FORECAST AREA WEDNESDAY THROUGH THURSDAY. Q-VECTOR CONVERGENCE...ISENTROPIC ASCENT...AND ACCOMPANYING THETA-E RIDGES SUGGEST A CHANCE OF THUNDERSTORMS THROUGH THIS PERIOD. DRIER...MORE STABLE AIR MASS WILL DOMINATE THE FORECAST AREA ON FRIDAY INTO SATURDAY MORNING. A SHORTWAVE WILL SLIDE INTO THE WISCONSIN AS AN ASSOCIATED SURFACE RIDGE STARTS TO SLIDE OFF TO THE EAST. A CHANCE OF SHOWERS AND THUNDERSTORMS WILL THUS RETURN SATURDAY AFTERNOON THROUGH SUNDAY. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JLB(UPDATE) DLG(PREV DISC) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1019 AM CDT MON JUL 24 2006 .UPDATE... WITH SHORT WAVE DROPPING DOWN FROM EASTERN NORTH DAKOTA AND 12Z RUC SHOWING THETA E ADVECTION CONCENTRATING OVER EAST CENTRAL AND SOUTHEAST MN...AND WESTERN WI FOR AFTERNOON AND EVENING...WILL UP POPS FOR THIS AREA. PLUME OF STEEP MID LEVEL LAPSE RATES ADVECTING INTO THIS AREA AS WELL. && .PREV DISCUSSION... /ISSUED 402 AM CDT MON JUL 24 2006/ DISCUSSION... THUNDERSTORMS IN PROGRESS EARLY THIS MORNING JUST EAST OF THE CWA AHEAD OF A SURFACE TROF AND 1000-850MB THETA-E ADVECTION. ANOTHER AREA OF SHOWERS AND THUNDERSTORMS NORTH OF THE CWA AHEAD OF AN APPROACHING COOL FRONT. SHORT TERM FORECAST RATHER PROBLEMATIC. ALTHOUGH THE COOL FRONT TO OUR NORTH WILL SETTLE INTO THE CWA TODAY AND THEN TURN STATIONARY...AS A STRONG SHORT WAVE OVER THE UPPER GREAT LAKES MOVES EAST...DIFFERENCES ARE NOTED IN THE TIMING OF ADDITIONAL SHORT WAVES IN THE NORTHWEST FLOW INTO THURSDAY BETWEEN THE NAM-WRF AND GFS. THIS PLAYS HAVOC WITH POTENTIAL CONVECTIVE EVENTS. SOME SIMILARITY EXISTS BETWEEN THE TWO MODELS TODAY AND TONIGHT. BELIEVE CONVECTION WILL REDEVELOP THIS AFTERNOON OVER CENTRAL MN AND WEST CENTRAL WI AND DROP SE DURING THE EVENING. RATHER STRONG INSTABILITY DEVELOPS AHEAD OF THE FRONT THIS AFTERNOON ALONG WITH CONVERGENCE NOTED ALONG THE 850MB TROF AXIS. SMALL CONVECTIVE CHANCES ON TUESDAY WITH THE STATIONARY FRONT MEANDERING ACROSS THE REGION. TUESDAY NIGHT LOOKING INTERESTING AND INCREASED POPS INTO THE LIKELY CATEGORY ACROSS THE EASTERN CWA. THIS WAS BASED ON AGREEMENT BETWEEN THE ECMWF AND NAM-WRF ON THE NEXT SHORT WAVE AND DEVELOPING WARM FRONT. PW'S INCREASE TO AROUND 1.75 INCHES WITH THE 310K THETA SURFACE FROM THE NAM-WRF SHOWING STRONG ADIABATIC OMEGA DEVELOPING OVER THE EASTERN CWA IN THE EVENING AND PERSISTING THROUGH MUCH OF THE NIGHT. INCLUDED HEAVY RAIN WORDING FOR EASTERN AREAS AS WELL. POPS DIMINISH ON WEDNESDAY AS THE SHORT WAVE MOVES SOUTHEAST. HIGH TEMPERATURES TO REMAIN WARM...UPPER 80S TO LOWER 90S...WITH 850MB TEMPERATURES RUNNING AT LEAST 20 DEG C OR WARMER. EXPECT THE WARMEST READINGS OVER WEST CENTRAL MN. LONGER TERM...THURSDAY THROUGH MONDAY 00Z GFS AND ECMWF ARE ACTUALLY IN FAIRLY CLOSE AGREEMENT ON THE OVERALL PATTERN THRU THE EXTENDED...WITH BOTH SHOWING A FLATTENING OF THE UPR RDG /AND A MORE ZONAL FLO PATTERN/ LATE IN THE WK...AND AN AMPLIFICATION OF THE UPR RDG INTO THE NRN PLAINS BY THE END OF THE WKEND. HAVE KEPT THE CHC POPS GOING FOR THU AND THE SLGT CHC POPS FOR THU NGT WITH FRONT COMING THRU...AND S/WVS MOVING THRU THE FA. BY MID TO LATE WKEND...PRE- FRONTAL THERMAL RDG SETS IN...WHICH SHUD BRING SOME LO TO MID 90 MAX TEMPS TO THE AREA. TWEAKED THE POP/WX GRIDS ON SAT AFTN AND NGT...WITH LO LVL WAA AND PARADE OF S/WVS BEING CONDUCIVE TO SOME SHWR/TSTM ACTIVITY...BEFORE LO TO MID LVL TEMPS GET A LITTLE TOO WARM FOR SUCH ACTIVITY. TEMPS SHUD DROP OFF A LITTLE ON MON...AS SFC HI DROPS THRU THE AREA. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ RAH/KAT/JPR mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 1017 AM EDT MON JUL 24 2006 .SHORT TERM /TODAY/...MJRTY OF PCPN HAS MVD OFFSHR. FRNT IS ALSO OFFSHR WI N AND NE FLO OVR CWA. FOG AND ST BEING REPRTD IN SRN HALF OF CWA. SFC ANALYSIS SHOWS A HINT OF A SFC WV FRMG OFF THE SC CST. THIS IS IN AGREEMENT WITH THE MDLS AND WL HELP BRING THE FRNT BCK N TDY. POPS WL INCRS FRM S TO N AS FRNT MVS N. 06Z GFS BRINGS IT N OF CWA LTR TNGT. HWVR LATEST RUC KPS IT FRTHR S THAN GFS TIL AT LEAST SS. WL KP TREND IN GRIDS AS IS. WL PIDDLE WI SKY AND TEMP TO MATCH CURRNT TREND. OTHRWS NO CHCS XPCTD. && .AVIATION...CURRENTLY HAVE MVFR CIGS OVER THE TERMINALS BUT EXPECT IMPROVING CONDITIONS TO VFR IN THE NEXT HOUR OR TWO. LIGHT NORTHEAST WINDS WILL BECOME SOUTHEASTERLY BY LATE AFTERNOON AS FRONT TO THE SOUTH TRIES TO LIFT NORTH. WITH FRONT IN THE AREA EXPECT SCT SHRA/TS TO DEVELOP DURING PEAK HEATING. && .MARINE...NO UPDATE NEEDED THIS MORNING AS MARINE GRIDS IN GOOD SHAPE. LIGHT NORTHEAST WINDS AOB 12 KT WILL VEER TO THE EAST OVER THE NORTH AND SOUTHEAST OVER SOUTHERN WATERS BY LATE AFTERNOON AS FRONTAL BOUNDARY BEGINS LIFTING NORTH. SEAS WILL AVERAGE 2 TO 4 FT. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ CGG/JW nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAND FORKS ND 1021 AM CDT MON JUL 24 2006 .UPDATE...MAIN CHALLENGE TODAY WILL BE ONGOING CONVECTION AND RESULTANT EFFECTS OF CLOUD COVER ON TEMPERATURES. SHORTWAVE EVIDENT ON WATER VAPOR ACROSS E ND PRODUCING CLUSTER OF THUNDERSTORMS ACROSS SE ND NOW PROPAGATING INTO WC MN. 12Z RUC SHOWS INSTABILITY AXIS INTO CENTRAL MN AND WOULD EXPECT THESE STORMS TO FOLLOW EXITING FA BY 18Z. MAIN SFC BOUNDARY WILL BE WELL S OF FA THIS AFTERNOON...AND WOULD EXPECT ANY ISOLD STORMS ACROSS S FA TO END BY MID-AFTERNOON. WILL ADJUST GRIDED POPS ACCORDING TO CURRENT SITUATION AND EXPECTATIONS ABOVE. MOST OF FA SHOULD SEE AMPLE TIME TO HEAT...EXCEPT WC FA WHICH WILL BE UNDER CLOUD COVER INTO THE EARLY AFTERNOON. WILL LOWER TEMPS ABOUT 5F ACROSS THIS AREA. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1035 AM CDT MON JUL 24 2006 .UPDATE...CURRENT GOES WATER VAPOR LOOPS INDICATING AN ORGANIZED SHORTWAVE TROUGH NEAR KFAR MOVING SOUTHEAST TOWARD THE FORECAST AREA. THIS HAS ORGANIZED A SHOWER AREA WITH CG LIGHTNING ACTIVITY OVER THE LAST FEW HOURS. MEANWHILE...THE LATEST SURFACE ANALYSES FROM 13/14Z INDICATE A CONVERGENCE FRONTAL BOUNDARY ASSOCIATED WITH SYSTEM OVER QUEBEC DRAGGING SOUTH INTO NRN WI/MN ALONG A KPBH-KRPD-KSTC LINE. KDLH RADAR SHOWS ECHOES ON AND NORTH OF THIS BOUNDARY WITH CG ACTIVITY TOO. 12Z RUC INDICATES THIS FRONT WILL BE SUPPORTED BY 850MB THETA-E CONVERGENCE LATER THIS AFTERNOON NEAR I-90. INSTABILITY IS GROWING IN CLEAR SKIES WITH A MOISTURE POOL ALONG THE FRONT OF 65-70F DEWPOINTS. LAPS DATA SHOWING AROUND 1000J/KG OF MLCAPE AHEAD OF FRONT KEAU-KMDZ AND MORE HEATING ON THE WAY. DEWPOINTS SHOULD POOL ALONG THE FRONT AND THIS POOL WILL DROP SOUTH TODAY SO 67-70F WILL BE FOUND ALONG I-90 AND NORTH. OVERALL...WITH SHORTWAVE TROUGH RIDING THE POLEWARD SIDE OF A WEAK UPPER LEVEL SPEED MAX MOVING RIGHT AT THE FORECAST AREA....THE FRONTAL POSITION TO BE JUST NORTH OF I-90 BY LATER AFTERNOON...AND INSTABILITY THAT SHOULD BE AROUND 2000 J/KG MLCAPE WILL PROVIDE UPPER FORCING...SURFACE TRIGGER...AND ENERGY FOR ENHANCED STORM COVERAGE LATER THIS AFTERNOON AND EARLY EVENING. HAVE INCREASED THE CHANGE FOR RAIN TO 40/50 BUT MAY NEED TO INCREASE THIS AGAIN BASED ON EARLY AFTERNOON DEVELOPMENTS. SEVERE THREAT...WITH THE INSTABILITY...HAIL AND WIND WILL BE THE THREATS AS MIDSHIFT ADVERTISED. THE WIND SHEAR IS STILL IN THE VERY LOW-LEVELS AND NOT DEEP SUPERCELL SHEAR. THE 0-3KM SHEAR TO ORGANIZE THE COLD POOL IS MODERATE SO THIS COULD PROVIDE BRIEF MULTICELL ORGANIZATION. THE BEST ORGANIZATION MAY COME FROM THE SHORTWAVE TROUGH WHICH COULD PROVIDE AN ORGANIZED LINE MODE IN HIGH INSTABILITY...POSSIBLY ENHANCING THE WIND THREAT. OUTLIER MODES...POSSIBLY A SPIN UP TORNADO ON THE FRONT IF UPDRAFTS CAN TAP THE LOW-LEVEL HELICITY PRESENT AND PERSIST. IF THE BOUNDARY SLOWS/STOPS OVER THE FORECAST AREA...NON-SUPERCELL TORS COULD BE A THREAT. HOWEVER...THIS SEEMS MUCH LESS LIKELY FOR TODAY. TIMING...LATER THIS AFTERNOON NORTH OF I-90 WILL BE THE MAIN THREAT...SLOWLY SHIFTING SOUTH/EAST WITH SHORTWAVE IN THE EARLY EVENING. LEADING EDGE OF SHORTWAVE WILL BE ON A WABASHA-TAYLOR LINE AROUND 5 PM. UPDATE SENT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ BAUMGARDT wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 330 PM EDT MON JUL 24 2006 .SYNOPSIS... 19Z WATER VAPOR AND 500MB RUC ANALYSIS SHOW LARGE DOMINANT UPPER RIDGE CENTERED OF THE SOUTHWEST UNITED STATES BEGINNING TO DE-AMPLIFY SLIGHTLY AS WEAK SHORT-WAVE ENERGY MOVES ASHORE ACROSS PACIFIC NORTHWEST. ANOTHER WEAK SHORTWAVE IS SEEN CROSSING THE UPPER MS VALLEY AND GREAT LAKES WHICH IS HELPING TO KICK OUT AND DE-AMPLIFY THE EAST COAST TROUGH. GLOBAL MODELS IN GENERAL AGREEMENT ON UPPER LEVEL PATTERN EVOLUTION ACROSS THE SOUTHERN TIER OF THE UNITED STATES. ALL SHOWING SHORTWAVES ENERGY/DYNAMICS REMAINING WELL TO THE NORTH THROUGH THE FORECAST PERIOD...ALTHOUGH THE DETAILS OF SHORTWAVE TIMING/STRENGTH DIFFER. STRONG UPPER RIDGE OVER THE EASTERN SUBTROPICAL ATLANTIC CONTINUES TO SLOWLY BUILD ACROSS THE SOUTHEAST AND EASTERN GOMEX THOUGH TUESDAY...AND IS OVERHEAD AND IN CONTROL BY LATE WEDNESDAY INTO THURSDAY. THIS EVOLUTION WILL HELP BRING TEMPS BACK TOWARD CLIMO OR EVEN A BIT ABOVE BY THE MIDDLE/END OF THE WEEK. POPS LOOK TO BE NEAR OR SLIGHTLY BELOW NORMAL FOR WED/THU BEFORE RETURNING TO NEAR NORMAL BY FRIDAY. AT THE SURFACE...SUBTROPICAL RIDGE LYING ACROSS CENTRAL/SOUTHERN FLORIDA DOWN INTO THE SOUTHEASTERN GOMEX BEGINS TO LIFT BACK NORTH OVERNIGHT AND THEN HOLDS OVER OR JUST SOUTH OF THE COASTAL WATERS THROUGH THE REMAINDER OF THE WORK WEEK. GRADIENT BECOME VERY WEAK BY WEDNESDAY AFTERNOON INTO THURSDAY ALLOWING AFTERNOON SEA-BREEZE DEVELOPMENT TO BECOME THE MAIN FOCUS FOR WIDELY SCATTERED-SCATTERED CONVECTION. && .SHORT TERM (TONIGHT THROUGH THURSDAY)... REST OF THE AFTERNOON AND EVENING HOURS WILL SEE CONTINUED AREAS OF CONVECTION ACROSS THE FORECAST AREA. STILL CAN NOT RULE OUT SOME ISOLATED HAIL AND STRONGER WINDS ACROSS OUR NORTHERN GA/AL ZONES WHERE BETTER MIXING TOOK PLACE DURING THE EARLIER PART OF THE DAY...HOWEVER...THIS SHOULD BE LIMITED TO ONLY THE STRONGEST STORMS SINCE SIGNIFICANT CONVECTION DURING THE AFTERNOON IS BEGINNING TO LIMIT CAPE/INSTABILITY AROUND THE AREA. MODELS (ESPECIALLY THE NAM) CONTINUE TO ADVERTISE A LOW/MIDDLE LEVEL WIND MAX BETWEEN 30-35KTS AROUND 850MB MOVING ACROSS THE PANHANDLE AND ESPECIALLY BIG BEND/COASTAL WATERS AREAS DURING THE EVENING/OVERNIGHT HOURS. STRONGER STORMS ACROSS THIS REGION MAY BE ABLE TO TAP SOME OF THIS WIND ENERGY DESPITE THE NEARLY MOIST ADIABATIC THERMO PROFILE. WILL HAVE TO KEEP AN CLOSE EYE ON THE OFFSHORE NOCTURNAL CONVECTION AS A FEW OF THESE STORMS MAY BE QUITE GUSTY. UPPER RIDGE AND SURFACE RIDGE COME OVERHEAD OR JUST SOUTH OF AREA ON TUESDAY. ALTHOUGH AVAILABLE MOISTURE...THERMODYNAMICS DO NOT LOOK AS ABUNDANT AS THE PAST TWO DAYS...ENOUGH RESIDUAL MOISTURE IS LEFT TO STILL EXPECT A FAIRLY ACTIVE SEABREEZE DURING THE AFTERNOON AND EVENING. OLD OUTFLOW BOUNDARIES WILL ALSO BE IGNITION POINTS FOR CONVECTION UP ACROSS OUR AL/GA ZONES. MODIFIED AFTERNOON SOUNDING STILL SHOWING BETWEEN 1800 AND 2300 J/KG OF CAPE FROM NORTH TO SOUTH WITH LI'S -4 TO -5C AND PW VALUES OVER 2". BY WEDNESDAY AND THURSDAY ...THE UPPER RIDGE IS CLEARLY IN CONTROL OF OUR WEATHER...AND FOR THAT REASON...TEMPERATURES ARE LIKELY TO BE BACK SEVERAL DEGREES ABOVE NORMAL ACROSS THE INTERIOR FOR LOCATIONS THAT REMAIN DRY. GENERALLY WENT WITH POPS ABOUT 10% BELOW CLIMO...BUT STILL IN THE CHANCE CATEGORY. UPPER RIDGE DIRECTLY OVERHEAD WILL CONTRIBUTE TO A WEAK CAP IN THE MIDLEVELS. DESPITE THIS CAP...EXPECTING MORE WIDELY SCATTERED ACTIVITY TO DEVELOP ALONG THE INLAND PENETRATING SEABREEZE AS FORECASTED CAPE VALUES ARE STILL AROUND 2000 J/KG WITH PW VALUES BETWEEN 1.8 AND 2.0" (NEAR NORMAL). .LONG TERM (FRIDAY THROUGH MONDAY)... WE WILL THEN SEE A RETURN TO NEAR NORMAL TEMPS AND POPS FOR THE REMAINDER OF THE FORECAST PERIOD. THE DEEP LAYER RIDGE E OF THE AREA SHOULD KEEP ANY FRONTS FROM PENETRATING THIS FAR S, AND THERE DO NOT APPEAR TO BE ANY TROPICAL SYSTEMS ON THE HORIZON. && .MARINE... SUBTROPICAL RIDGE AXIS LOCATED JUST TO THE SOUTH OF THE COASTAL WATERS TONIGHT WILL SLIDE BACK NORTH THROUGH THE DAY ON WEDNESDAY AND THEN REMAIN ACROSS THE COASTAL WATERS THROUGH THURSDAY NIGHT. THE RIDGE AXIS IS THEN FORECAST TO LIFT NORTH OF THE WATERS TOWARD THE END OF THE WORK WEEK AND BEGINNING OF THE UPCOMING WEEKEND. WITH THE RIDGE AXIS NEARBY THROUGH THE FORECAST PERIOD...WIND AND SEAS ARE EXPECTED TO REMAIN BELOW CAUTION LEVELS. && .AVIATION... NUMEROUS SHOWERS AND STORMS WILL CONTINUE TO BUFFET THE TAF SITES FROM TIME TO TIME THIS AFTERNOON...WITH IFR VIS AND WIND GUSTS TO 30 KTS IN THE STRONGER CELLS. THESE STORMS WILL GRADUALLY WIND DOWN FROM SW TO NE LATE THIS AFTERNOON AND EARLY EVENING...WITH DECENT FOG POTENTIAL ONCE AGAIN OVERNIGHT...ESPECIALLY AT ANY OF THE SITES WHICH RECEIVE RAINFALL AFTER SUNSET. && .FIRE WEATHER... A WEAK FRONTAL BOUNDARY JUST TO THE NORTH OF THE REGION WILL LIFT NORTHWARD DURING THE NEXT COUPLE OF DAYS...AS A HIGH PRESSURE SYSTEM BUILDS IN OVER THE NORTHERN GULF OF MEXICO. THIS WILL RESULT IN A GRADUAL DECREASE IN SHOWERS AND THUNDERSTORMS OVER THE AREA...ALONG WITH INCREASING AFTERNOON HIGH TEMPERATURES. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 74 91 73 95 / 50 60 30 30 PANAMA CITY 78 90 77 92 / 40 40 20 20 DOTHAN 73 91 73 94 / 50 50 30 30 ALBANY 73 92 73 94 / 50 50 30 30 VALDOSTA 73 91 73 95 / 50 60 30 40 CROSS CITY 74 89 73 93 / 40 50 20 40 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. && $$ AVIATION/FIRE WX...GOULD PUBLIC/MARINE...MROCZKA LONG TERM...WOOL fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 315 PM CDT MON JUL 24 2006 .DISCUSSION... 315 PM THE SURFACE BASE CONVECTIVE AVAILABLE ENERGY ARE FORECAST TO BE HIGHEST OVER WILL COUNTY IN NORTHEAST ILLINOIS AROUND 22 UTC. THESE VALUES WERE FROM THE RUC40 MODEL. THE MAXIMUM IS FORECAST TO MOVE INTO COOK AND DUPAGE COUNTY BY 00 UTC. THE INSTABILITY IS THERE BUT THERE IS NO LARGE SCALE FORCING. THE WRF_ARW SHOWS A WAVE PATTERN ACROSS CENTRAL WISCONSIN. THERE IS A NEAR ZONAL FLOW AT 700 MB. THIS MAY INDICATE SOME WAVES GENERATED BY FRONTOGENESIS IN CENTRAL WISCONSIN. THE WRF KEEPS THIS FEATURE NORTH OF THE FORECAST AREA. THROUGH THE NIGHT. AN UPPER AIR WAVE IS SEEN TO IN THE NORTHERN PARTS OF WISCONSIN. THIS MAY MOVE SOUTH AND PUSH THE FRONT SOUTH. WILL LEAVE A CHANCE OF THUNDERSTORMS FOR TUESDAY AS THE FRONT AND ITS UPPER AIR SUPPORT MAY MOVE SOUTH. THE RADAR SHOWS KELVIN HELMHOLTZ WAVES OVER THE FORECAST AREA. WE MAY HAVE THE SAME MIXED LAYER TUESDAY DURING THE DAY WITH CUMULUS CLOUDS FROM THE THERMALS AND SOUTH WIND IN THE MORNING. THERE IS FORECAST SOME CONVECTIVE AVAILABLE POTENTIAL ENERGY FOR TUESDAY AFTERNOON. THIS IS FROM THE GFS MODEL. WILL KEEP THE CHANCE PROBABILITY THROUGH FRIDAY NIGHT. THERE WILL BE SEVERAL SHORT WAVE TROUGHS MOVING THROUGH. THE GFS MAINTAINS THE FORECAST INSTABILITY THROUGH THE PERIOD. MADE LITTLE CHANGE FOR THE TEMPERATURE FORECASTS. && .AVIATION DISCUSSION FOR 18Z TAFS... 1250 PM CDT FORECAST ISSUE OF THIS FORECAST PERIOD IS THE CHANCE OF SHOWERS AND THUNDERSTORMS THAT COULD POP UP LATER THIS AFTERNOON AND TONIGHT. MAIN FORCING FOR THE CURRENT ISOLATED SHOWERS SEEMS TO BE A MID LEVEL TROUGH WORKING THROUGH WESTERN WISCONSIN/EASTERN IOWA AT 12Z. THE PREVIOUS CU HAVE FLATTENED OUT THERE DOESN'T SEEM TO BE MUCH FORCING LEFT WITH THIS WAVE FOR THE TAF SITES. AS THIS CLOUD DECK MOVES OFF TO THE SOUTH...SOME AFTERNOON HEATING COULD POP UP A FEW THUNDERSTORMS...BUT WILL BE TOO ISOLATED THAT CHANCES ARE VERY LOW OF THEM REACHING THE TAF SITES. THE OTHER MAIN FORECAST ISSUE IS THE WINDS. SOUTHWESTERLY WINDS WILL BE THE NORM THROUGHOUT AS HIGH PRESSURE MAINTAINS ITS HOLD OVER THE SOUTHEAST US AND A FRONTAL BOUNDARY HANGS OUT OVER NORTHERN WISCONSIN. WINDS BETWEEN 900-850MB ARE BETWEEN 25-30 KTS. SO IF THESE WINDS MIX TO THE SFC...THERE COULD BE SOME GUSTS THAT REACH 25 KTS OR SO. WITH A FAIRLY HIGH TEMPERATURE/DEW POINT DEPRESSION IN PLACE FROM THE SFC UP TO 10KFT...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE TAF FORECAST PERIOD...WITH THE EXCEPTION OF A SHOWER PASSING NEAR A SITE. HALBACH && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LM...NONE. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 125 PM EDT MON JUL 24 2006 .AVIATION... SFC ANALYSIS AT 17Z DEPICTED A COLD FRONT FROM CNTRL ONTARIO ...SOUTHWEST INTO NRN WISCONSIN AND SRN MN. THIS FRONT IS NOT EXPECTED TO MAKE IT INTO OUR REGION. OF GREATER SIGNIFICANCE OVER THE NEXT 24 HOURS WILL BE HOW SVRL S/WVS IN THE WNW FLOW ALOFT WILL AFFECT THE REGION. ONE SUCH DISTURBANCE WAS LOCATED FROM NRN LOWER MICHIGAN INTO SRN WISCONSIN. THIS FEATURE IS FCST TO BE SE OF THE REGION BY 06Z. SCATTERED SHOWERS AND THUNDERSTORM HAD DEVELOPED WITH THIS SYSTEM EARLIER THIS MORNING...AND SOME OF THE ACTIVITY WAS STILL HANGING ON ACRS SOUTHEAST LAKE MICHIGAN. AT THIS TIME...THERE IS A SMALL CHANCE OF SHOWERS AND THUNDERSTORMS ACRS SOUTHWEST LOWER MICHIGAN INTO FAR NORTHWEST INDIANA THROUGH THE EVENING HOURS AS SOME SFC BASED CONVECTION MY INITIATE. HOWEVER...THE PROBABILITY REMAINS TOO LOW AT THIS POINT TO MENTION AT KSBN...AND WILL MONITOR RADAR TRENDS THROUGH THE AFTN HOURS. ANOTHER S/WV ENTERING WRN MN AT THIS TIME IS FCST TO DROP SE THIS EVENING...THEN IT WILL MOVE MORE EASTERLY ACRS SRN WISCONSIN/LOWER MICHIGAN LATE TONIGHT INTO TUESDAY. BEST LOW LVL FORCING/MOISTURE CONVERGENCE/INSTABILITY WILL REMAIN NORTH OF THE REGION THROUGH TUESDAY...AND AS A RESULT WILL KEEP TAFS DRY. THERE WILL BE...HOWEVER...AN INCREASE IN MID AND HIGH LVL CLOUDS FROM THE CONVECTION UPSTREAM THAT WILL SPILL SOUTHEAST INTO THE REGION OVERNIGHT AND ON TUESDAY. SOUTH/SOUTHWEST WINDS OF 10 TO 20 KNOTS WITH LOCAL GUSTS TO 25 KNOTS THIS AFTN WILL SUBSIDE ONCE THE SUN SETS AROUND 01Z. && .PREV DISCUSSION... UPDATE... KIWX RADAR WAS SHOWING SCATTERED SHOWERS AND THUNDERSTORMS ACRS SOUTHERN LAKE MICHIGAN EARLY THIS AFTERNOON. THESE SHOWERS AND THUNDERSTORMS WERE IN ASSOCIATED WITH AN UPR LVL S/WV THAT STRETCHED FROM NRN LOWER MICHIGAN SOUTHWEST INTO SRN WISCONSIN. THIS S/WV WILL SLOWLY MOVE SE INTO THE FCST AREA THROUGH THIS EVENING. HAVE INTRODUCED A 30 PERCENT CHC OF SHOWERS AND THUNDERSTORMS ACRS SOUTHWEST LOWER MICHIGAN AND FAR NORTHWEST INDIANA TO ACCOUNT FOR THE POSSIBILITY OF PCPN IN THESE AREAS AS THEY WILL BE THE MOST LIKELY REGION TO SEE SOME ACTIVITY THIS AFTN AND EVENING. WILL INTERROGATE MODEL DATA AND OBSERVATIONAL TRENDS TO SEE IF THE AREA HAS TO BE EXPANDED AND/OR EXTENDED IN TIME BEYOND THIS EVENING WITH THE AFTN FCST PACKAGE. CURRENT FCST TEMPS ARE STILL ON TRACK...SO NO CHANGES NEEDED. SHORT TERM... TODAY AND TONIGHT. RIDGE AXIS HAS NOW SHIFTED EAST OF THE FORECAST AREA...ALLOWING WAA TO BEGIN. 850 MB TEMPS WILL CLIMB INTO THE UPPER TEENS BY AFTERNOON. THIS COMBINED WITH WHAT SHOULD BE A GOOD DEAL OF SUNSHINE...AT LEAST TO START WITH...WILL ALLOW TEMPS TO CLIMB BACK TO NORMAL OR EVEN SLIGHTLY ABOVE NORMAL LEVELS TODAY. DEWPTS WILL ALSO BE ON THE INCREASE WITH READINGS IN THE LOW TO MID 60S COMMON UPSTREAM. FRONTAL BOUNDARY MAKING SLOW PROGRESS SOUTH FROM MINNESOTA AND LK SUPERIOR. LINE OF SHOWERS AND STORMS IN ADVANCE OF THIS DIVING SOUTH AND EAST INTO NORTHERN LWR MI...POSING NO CONCERN. A SMALL LINE OF SHOWERS AND STORMS HAS DEVELOPED OVER THE PAST HOUR EAST OF LACROSSE WISCONSIN. PROFILER DATA IS MISSING AT THIS TIME...BUT RUC SHOWS A 30+KT LLJ FEEDING INTO THIS AREA WITH INCREASING LOW LEVEL THETA-E. TRENDS AND 850-300 MB THICKNESS PLOTS SHOW THIS ACTIVITY SHOULD ALSO DRIFT INTO MICHIGAN AND POSE NO THREAT. WILL NEED TO MONITOR TRENDS TO MAKE SURE BUT WILL MAINTAIN A DRY FORECAST TODAY. CU RULE SHOWS DIURNAL DEVELOPMENT ONCE AGAIN...BUT VALUES NOT AS HIGH AS YESTERDAY. ALSO WITH INCREASING SFC WINDS AS GRADIENT INCREASES AND STRONGER WIND FLOW IS MIXED DOWN SOMEWHAT...LAKE BREEZE DEVELOPMENT UNLIKELY. SCT CU WILL DEVELOP ONCE AGAIN...BUT CU RULE SHOWING NOT AS MUCH COVERAGE AS TODAY. FOCUS BEGINS TO TURN TONIGHT ONTO ABOVE MENTIONED FRONTAL BOUNDARY ACROSS LWR MI THAT WILL BE MAKING SLOW PROGRESS SOUTH. COMPLEX OF STORMS EXPECTED TO DEVELOP AND MOVE ALONG IT TONIGHT. TRACK OF THIS SHOULD REMAIN FAR ENOUGH NORTH TO ALLOW CONTINUED DRY FORECAST TONIGHT. WITH CONTINUED WAA AND INCREASING MSTR LOWS WILL BE A GOOD 10 DEGREE WARMER IN MANY LOCATIONS TONIGHT...DROPPING ONLY TO THE MID TO UPPER 60S. LONG TERM... TUESDAY THROUGH SUNDAY. NOT QUITE READY TO THROW LATEST NAM OUT THE WINDOW. SHORTWAVE ENERGY OVER NORTHEAST MT SHOULD CONTINUE TO DAMPEN AS LONGWAVE TROF ACROSS EASTERN STATES DEAMPLIFIES AS NEW ENGLAND WAVE LIFTS NORTHEAST AND GREAT BASIN HIGH SLOWLY WEAKENS AND PUSHES SOUTH WHERE NAM HAS SHOWN RUN TO RUN CONSISTENCY HERE. GFS AND NAM WITH HUGE DISPARITIES WITH REGARDS TO MOS POPS TUESDAY NIGHT...CATEGORICAL VS. LT 20. TUE NIGHT MCS GENERATION PER GFS A BIT SUSPECT WITH CONVECTIVE SCALE FEEDBACK. PREFERENCE LIES TOWARD CONSISTENCY AND NAM AND AWAIT MORE STRONGER ENERGY OVER NORTHWEST TERRITORIES TO DIVE SOUTHEAST INTO CENTRAL CANADA/UPPER PLAINS BY MIDWEEK. DEEP MOIST TRANSPORT AHEAD OF SYSTEM WITH PWAT INCREASING TO NEAR 2 INCHES AND ARRIVAL OF BETTER KINEMATICS/INSTABILITY LATE WEDNESDAY AFTERNOON WITH POTENTIAL MCS DEVELOPMENT UPSTREAM TO MOVE ESE THROUGH SOUTHERN GREAT LAKES WED NIGHT....HAVE RAISED TSRA POPS TO HIGH CHANCE RANGE WED NIGHT AND THROUGH THU FOR POTENTIAL AIRMASS DESTABILIZATION AND LOW LEVEL VEERING AHEAD OF APPROACHING MID LEVEL WAVE THU. NO OTHER CHANGES REMAINDER OF FORECAST. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE/AVIATION...HICKMAN SHORT TERM...FISHER LONG TERM....MURPHY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 311 PM CDT MON JUL 24 2006 .SYNOPSIS... EARLIER SHOWERS HAVE DISSIPATED OVER THE SOUTHWESTERN CWA AND CLOUDS ARE BREAKING. MEANWHILE...CONVECTION IS FIRING IN MN/WI ALONG THE SURFACE BOUNDARY...AND ELEVATED ECHOES ARE SHOWING UP IN NORTHERN IA BENEATH THE ACCAS FIELD. 19Z MSAS ANALYSIS INDICATES SURFACE LOW CENTERED OVER THE UP OF MI/NORTHERN LAKE MI WITH SECONDARY LOW OVER CENTRAL SD. SURFACE BOUNDARY EXTENDS BETWEEN LOW CENTERS AND IS THE FOCUS OF THE MN/WI CONVECTION. PRESSURE FALLS OF 2MB/3HR WERE CENTERED OVER SOUTHEASTERN IA AT 19Z. SUBJECTIVE 12Z UPPER AIR ANALYSIS INDICATES NORTHWESTERLY FLOW OVER THE REGION...WITH UPPER TROUGH PASSING EAST OVER THE GREAT LAKES...UPPER HIGH CENTERED OVER THE FOUR CORNERS...AND SEVERAL WEAK WAVES UPSTREAM EMBEDDED IN THE FLOW. BROAD AREA OF 500MB HEIGHT FALLS AT THE TOP OF THE RIDGE INDICATE SOME FLATTENING AND MAKE PROGRESSION OF INDIVIDUAL WAVES HARDER TO PICK OUT. 850MB LOW WAS CENTERED IN NORTHERN ONT WITH SECONDARY LOW OVER NORTHERN WY/SOUTHERN MT. MOISTURE WAS POOLING ALONG THE BOUNDARY EXTENDING BETWEEN LOWS AND WAS ALSO STARTING TO RETURN FROM THE GULF. && .SHORT TERM...TONIGHT AND TOMORROW... FORECAST FOCUS IS MAINLY ON POTENTIAL FOR PRECIP TO GRAZE THE NORTHERN CWA TONIGHT...FOLLOWED BY POTENTIAL FOR CONVECTIVE DEVELOPMENT TOMORROW AFTERNOON. ELEVATED STORMS IN NRN IA ARE PROGRESSING SOUTHEASTWARD AND SHOULD REACH THE CWA BY ABOUT 00Z. MID-LEVEL LAPSE RATES WERE STRONG IN THE 12Z KDVN SOUNDING AND WERE STILL AROUND 7.5 C/KM OVER NORTHERN IA AT 19Z ACCORDING TO RUC ANALYSIS...BUT STORMS WILL OUTRUN 850MB SUPPORT AS THEY PROGRESS EASTWARD AWAY FROM THE ELEVATED BOUNDARY AND SHOULD WEAKEN AS THEY APPROACH THE CWA. LOW-LEVEL JET LATER TONIGHT MAY HELP FUEL A RESURGENCE OF THESE STORMS...BUT AGAIN EXPECT THEM TO REMAIN NON-SEVERE THIS FAR SOUTH OF THE 850MB BOUNDARY. MODELS PROGRESS THE TSRA ACROSS THE NORTHERN CWA THROUGH THE EARLY MORNING HOURS...AND WOULD AGREE WITH THIS SCENARIO WITH LOW-LEVEL JET FEED AND BUILDING MOISTURE. ACTIVITY SHOULD KEEP TEMPS UP TONIGHT IN THE NORTH...AND HAVE BUMPED UP MINS THERE BY A FEW DEGREES. ACTIVITY MAY TAKE SOME TIME TO CLEAR THE NORTHEASTERN CWA IN THE MORNING...ALSO HOLDING MAX TEMPS TOMORROW DOWN BY A FEW DEGREES. OTHERWISE...EXPECT TEMPS TOMORROW TO BE SIMILAR TO TODAY WITH WARMING 850MB TEMPS AND CONTINUED SOUTHWESTERLY FLOW WITH STRONG MIXING COUNTERED BY INCREASED MOISTURE AND A GREATER AMOUNT OF CLOUDS THAN TODAY. MODELS INDICATE CONVECTION INITIATING IN WESTERN/NORTHERN IA TOMORROW LATE AFTERNOON ALONG THE SURFACE BOUNDARY AS IT DRIFTS EASTWARD...SUPPORTED BY A SHORTWAVE ROTATING THROUGH THE NORTHWESTERLY FLOW. HAVE SLIGHT CHANCE POPS IN THE NORTHEASTERN THIRD OR SO TO CAPTURE POTENTIAL FOR INITIATION NEAR THE CWA...BUT BELIEVE MAIN SHOW WILL OCCUR BEGINNING TUESDAY EVENING. ..MAYES.. && .LONG TERM...TOMORROW NIGHT THROUGH MONDAY... NW FLOW WITH EMBEDDED SHORTWAVES KEEP THUNDERSTORM CHANCES IN FORECAST THROUGH FRIDAY...THEN UPPER RIDGE OUT WEST BEGINS TO FLATTEN AND SHIFT EAST TOWARD LOCAL AREA OVER WEEKEND INTO NEXT WEEK. WARMER TEMPERATURES ALOFT UNDER RIDGE EXPECTED TO END STRETCH OF ACTIVE WEATHER...WITH ASSOCIATED CAP PROVIDING HOT BUT DRY WEATHER SAT THROUGH MON. TUESDAY NIGHT INTO WEDNESDAY LOOKS TO HAVE BEST CHANCES FOR WIDESPREAD RAIN AS UPPER LEVEL SHORTWAVE TROUGH CURRENTLY TOPPING RIDGE OVER MT AND ALBERTA SLIDES SE OVER AREA. AT THE SAME TIME...H8 RETURN FLOW OF GULF MOISTURE CREEPING NORTH INTO SOUTHERN PLAINS TODAY...WILL ALREADY BE WELL ENTRENCHED OVER AREA. SHORT TERM MODELS IN GENERAL AGREEMENT WITH MCS DEVELOPING UPSTREAM OVER NW IA OR SW MN TUE NIGHT... SPREADING SE OVER LOCAL AREA BY MORNING. GFS HAS CONVECTIVE FEEDBACK ISSUES WITH LARGE QPF BULLSEYE OVER 3 INCHES NE OF DVN 00-06Z. HOWEVER...WITH PRECIPITABLE WATER SHOWN EXCEEDING 2 INCHES OVER MUCH OF AREA...HEAVY RAIN IS DEFINITE POSSIBILITY IF LARGE MCS MATERIALIZE OR TRAINING OF CELLS OCCURS. DISSIPATING MCS WILL LIKELY LEAVE MESO BOUNDARIES ON WED ALTHOUGH MAIN COLD FRONT DEPICTED TO REMAIN WELL W-NW OF AREA. ADDITIONAL MID LEVEL SHORTWAVES DEPICTED WED WILL PRODUCE ADDITIONAL THUNDERSTORMS ALONG THESE BOUNDARIES WITH PLENTY OF LOW LEVEL MOISTURE AND INSTABILITY LINGERING. HAVE INCREASED POPS TO LIKELY FOR TUE NIGHT INTO WED. THE UPPER LEVEL TROUGH LINGERS OVER AREA WED NIGHT INTO THU WITH WEAK BOUNDARIES AND ABUNDANT MOISTURE AT H8 CONTINUING THUNDERSTORM CHANCES THROUGH FRIDAY. UPPER RIDGE AND ASSOCIATED CAPPING BUILDS OVER AREA LATE FRI INTO SATURDAY TO END MENTIONABLE CHANCES OF PRECIPITATION. WENT A FEW DEGREES ABOVE GUIDANCE SUN AND MON WITH HIGHS IN 90S MOST AREAS FAVORING CONSISTENT ECMWF SOLUTION WITH HIGHER UPPER LEVEL HTS. ..SHEETS.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ MAYES/SHEETS ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 347 PM EDT MON JUL 24 2006 .DISCUSSION... SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT... 18Z SURFACE ANALYSIS SHOWS AN INVERTED SURFACE TROF OVER ERN TENNESSEE TO ERN KENTUCKY. MODELS WERE INDICATING INCREASED MEAN RH VALUES AND OMEGA MOVING NORTHWARD OVER EXTREME SOUTHEASTERN KENTUCKY. VISIBLE SATELLITE WAS SHOWING A MORE EXTENSIVE CU FIELD IN THE SE PORTION OF OUR CWA. A LESS DEVELOPED CU FIELD WAS OVER THE REMAINDER OF THE AREA. THIS INDICATES MODEL SOUNDINGS ARE DEPICTING THE ATMOSPHERE ACCURATELY THIS AFTERNOON WITH LOWER CONVECTIVE TEMPS AND A WEAKER CAP IN THE SE PORTION OF THE CWA. JACKSON WEATHER SERVICE DOPPLER RADAR SHOWED SOME ISOLATED SHOWERS FIRING AS OF 3 PM IN BELL COUNTY...AND IN EASTERN TENNESSEE AND WESTERN VIRGINIA. I KEPT THE MENTION OF ISOLATED SHOWERS OR THUNDERSTORMS IN THE EVENING IN THE SOUTHERN AND EASTERN PORTION OF THE CWA. AFTER THE CONVECTION DISSIPATES THIS EVENING...SOME AREAS OF MAINLY VALLEY FOG WILL FORM AGAIN TONIGHT. WENT WITH LOWS GENERALLY IN THE MID 60S IN MOST AREAS TONIGHT. FOR TUESDAY NGM...WRF AND GFS ARE SHOWING A WEAK H5 TROF AND AN ASSOCIATED VORT MAX MOVING THROUGH. MODELS ARE INDICATING CAPES OF AROUND 1000 TO 1500 J/KG IN THE AFTERNOON. MODEL SOUNDINGS ARE SHOWING A WEAK CAP IN PLACE...BUT WITH CONVECTIVE TEMPS IN THE MID 80S WE SHOULD BE ABLE TO BREAK THROUGH THE CAP. SHOULD SEE SOME ISOLATED CONVECTION FIRING AGAIN IN THE AFTERNOON. MIXING DOWN 850 MB TEMPS...AND ACCOUNTING FOR SOME CLOUD COVER...I WENT WITH MAX TEMPS IN THE MID TO UPPER 80S. TUESDAY NIGHT ANY ISOLATED CONVECTION FROM THE DAYTIME HEATING AND THE UPPER WAVE SHOULD DISSIPATE IN THE EVENING. WENT WITH MIN TEMPS AROUND 65 IN THE VALLEYS TO AROUND 70 ON THE RIDGES. WEDNESDAY THE WRF MODEL IS SHOWING A WEAK VORT MAX MOVING THROUGH. MODEL SOUNDINGS INDICATE ANOTHER WEAK MID LEVEL CAP...BUT AGAIN WITH CONVECTIVE TEMPS IN THE MID 80S WE SHOULD BE ABLE TO BREAK THROUGH THE CAP. THIS SHOULD RESULT IN SOME ISOLATED CONVECTION FIRING AGAIN IN THE AFTERNOON. MIXING DOWN 850 MB TEMPS AND ACCOUNTING FOR SOME CLOUDS YIELDS HIGH TEMPS IN THE MID TO UPPER 80S OVER THE AREA. GENERALLY SHOULD BE A DEGREE OR TWO WARMER THAN TUESDAY. FOR WEDNESDAY NIGHT I KEPT A MENTION OF ISOLATED SHOWERS OR THUNDERSTORMS EARLY. OVERNIGHT LOWS SHOULD BE FROM THE UPPER 60S TO THE LOWER 70S WITH A LITTLE CLOUD COVER AND INCREASED DEW POINTS. LONG TERM...THURSDAY THROUGH MONDAY... THE MODELS ARE IN PRETTY GOOD AGREEMENT AND HAVE HAD GOOD RUN TO RUN CONSISTENCY. EVEN THE ENSEMBLES ARE IN PRETTY GOOD AGREEMENT. AS SUCH...JUST MADE A COUPLE OF MINOR ADJUSTMENTS TO THE PREVIOUS FORECAST. THE UPPER TROUGH OVER THE AREA IS IN THE PROCESS OF TRANSITIONING TO MORE ZONE PATTERN. AT THE SURFACE...THE BERMUDA HIGH WILL BUILD BACK INTO THE SOUTHEAST US ALLOWING FOR A RETURN OF GULF MOISTURE TO THE AREA. THIS WILL HELP TO SPARK SOME SCATTERED...MOSTLY AFTERNOON...SHOWERS AND THUNDERSTORMS ACROSS THE REGION FROM THURSDAY THROUGH SUNDAY. THE FORECAST AREA WILL STAY IN THE WARM SECTOR AS ALL THE FRONTAL SYSTEMS ATTEMPTING TO OVERCOME THE SURFACE RIDGE WILL BE REPULSED AND WILL STAY TO THE NORTH. THE TEMPERATURES AND HUMIDITIES SHOULD STAY ABOVE SEASONABLE NORMS DURING THE PERIOD. ONLY MADE MINOR ADJUSTMENT TO THE TEMPERATURE FORECASTS SINCE THE MODELS HAVE BEEN BEHAVING SO WELL. && .PREV DISCUSSION... 1022 AM EDT MON JUL 24 2006 DISCUSSION... UPDATED THE FORECAST TO ADD ISOLATED SHOWERS AND THUNDERSTORMS OVER OUR SOUTHERN AND EASTERN CWA. RUC...WRF AND GFS ARE SHOWING AN AREA OF INCREASED MEAN RH AND OMEGA MOVING NORTHWARD FROM ERN TENNESSEE. THIS APPEARS TO BE ASSOCIATED WITH A WEAK INVERTED SURFACE TROF OVER ERN TENNESSEE INDICATED ON THE 13Z SURFACE ANALYSIS. MORNING SOUNDINGS SHOW A WEAK MID LEVEL CAP IN PLACE...BUT MODEL SOUNDINGS SHOW THIS CAP WEAKENING LATER THIS AFTERNOON OVER THE SRN AND SE PORTIONS OF THE CWA. THIS SHOULD LEAD TO AT LEAST ISOLATED CONVECTION FIRING. CONVECTIVE TEMPS SHOULD LOWER INTO THE UPPER 70S IN SOME AREAS...WITH MID 80S REMAINING IN THE CENTRAL AND NRN PORTION OF THE CWA WHERE THE CAP REMAINS A LITTLE STRONGER. ALSO LOWERED TEMPS A FEW DEGREES...ESPECIALLY WHERE THE CONVECTION IS EXPECTED TO FIRE. ALSO INCREASED CLOUD COVER AND MENTIONED PARTLY CLOUDY IN OUR ENTIRE CWA...WITH CU DEVELOPING IN THE LATE MORNING AND AFTERNOON. UPDATED TEXT AND GRAPHICAL FORECASTS HAVE BEEN SENT. 300 AM EDT MON JUL 24 2006 DISCUSSION... HIGH PRESSURE STILL FIRMLY IN CONTROL OF WEATHER ACROSS FORECAST AREA. 0Z 500 AND 850 HPA CHART ANALYSIS SHOW RIDGING ALSO IN PLACE AT MIDLEVELS...WITH LARGE AREA OF 500 HPA HIGH PRESSURE IN PLACE OVER WESTERN UNITED STATES...WHICH SHOULD PUSH EASTERN TROUGH OUT OF THE STATES IN THE NEXT DAY OR SO. CURRENT WATER VAPOR AND IR SATELLITE IMAGERY INDICATING THAT A LARGE AMOUNT OF DRY AIR IS CURRENTLY IN PLACE ACROSS MUCH OF THE MIDWEST. WITH THIS IN MIND...AND WITH NO STRONG SYSTEM TO PUSH HIGH PRESSURE OUT OF AREA...ANTICIPATE A DRY FORECAST ONCE AGAIN THROUGH MIDWEEK THIS WEEK. WENT WITH GFS SOLUTION ONCE AGAIN FOR CONSISTENCY. MADE A FEW MINOR TWEAKS TO CLOUD COVER FORECAST...GENERALLY DECREASING CLOUD COVER THROUGH WEDNESDAY...WITH A GRADUAL INCREASE IN CLOUD COVER TO MOSTLY CLOUDY FOR WEDNESDAY NIGHT INTO THURSDAY. MODELS INDICATING THAT STRONG LOW LEVEL JET WILL DEVELOP AND MOVE INTO THE AREA FROM THE SOUTHWEST WEDNESDAY NIGHT. AT THIS TIME MODELS ARE NOT MOVING ANY ORGANIZED WEATHER SYSTEMS ACROSS THE EASTER HALF OF THE UNITED STATES WEDNESDAY NIGHT...SO DECIDED TO REMOVE POPS FROM FORECAST THROUGH EARLY THURSDAY. IT APPEARS THAT THE INGREDIENTS FOR PRECIPITATION WONT FULLY COME TOGETHER UNTIL THURSDAY AFTERNOON. WINDS WERE TWEAKED SLIGHTLY ALSO TO REFLECT CURRENT MODEL OUTPUT...WITH A PERSISTENT SOUTH TO SOUTHWEST WIND DIRECTION ANTICIPATED AT THIS TIME THROUGH DAY 3. DEWPOINTS LOOKED GOOD AND WERE UNCHANGED. ADJUSTMENTS WERE ALSO MADE TO WEATHER AND QPF GRIDS TO REFLECT CHANGES MADE TO POP GRIDS. STILL LEAVING IN MENTION OF VALLEY FOG FOR TONIGHT AND TUESDAY NIGHT. 900 PM EDT SUN JUL 23 2006 HIGH PRESSURE IS FIRMLY IN CONTROL THIS EVENING WITH THE AFTERNOON CU FIELD NOW LARGELY DISSIPATED. SKIES SHOULD REMAIN CLEAR OVERNIGHT... EXCEPT WHERE FOG AND STRATUS FORM TOWARD DAWN. ONLY POINT OF CONTENTION WITH THE INHERITED FORECAST IS MIN TEMPS TONIGHT. BELIEVE WE/LL BE ABLE TO DROP A LITTLE LOWER THAN OBSERVED LAST NIGHT WITH BETTER RADIATIONAL COOLING CONDITIONS...I.E. LESS CLOUD COVER AND SLIGHTLY LOWER SURFACE DEWPOINTS. FULLY EXPECT A FEW MID 50S IN THE MORE SHELTERED VALLEY LOCATIONS AND WILL ADJUST MIN TEMP GRID TO REFLECT THIS. MAJORITY OF LOCATIONS WILL SETTLE AROUND 60 HOWEVER...SO WILL ELECT NOT TO UPDATE THE ZONES AT THIS TIME. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WJM/JJ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 354 PM EDT MON JUL 24 2006 .DISCUSSION... MAIN FORECAST CONCERN IS THUNDERSTORM CHANCES THROUGH THE NEXT FEW DAYS AND ANY SEVERE WEATHER CONCERNS WITH THOSE. CURRENT WEATHER...19Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS STILL SHOW A RIDGE IN THE WESTERN U.S. AND A TROUGH IN THE EASTERN U.S....BUT THESE ARE A LOT LESS AMPLIFIED THAN THE PAST FEW DAYS. NONETHELESS...THERE IS STILL PLENTY OF ACTION. CURRENT SHRTWV OF INTEREST...AIDING THUNDERSTORMS ACROSS THE SOUTH HALF OF THE U.P. AND NORTHERN WISCONSIN. AT THE MOMENT...IS MOVING THROUGH LAKE SUPERIOR. THIS SHRTWV IS REFLECTED AT THE SURFACE BY A WEAKENING COLD FRONT/TROUGH... STRETCHING FROM JUST SOUTH OF DULUTH TO RHINELANDER AND NORTHEAST TO WHITEFISH POINT. THE COLD FRONT/TROUGH IS ALSO BEING ENHANCED BY LAKE BREEZES OFF OF LAKES MICHIGAN AND SUPERIOR DUE TO INLAND TEMPERATURES AWAY FROM CONVECTION WARMING INTO THE 80S. SOME OF THE THUNDERSTORMS HAVE PRODUCED HAIL ACROSS NORTHERN WISCONSIN. OTHER SHRTWVS...SOMEWHAT WEAKER THAN THE ONE MOVING THROUGH NOW...CAN BE SEEN OFF TO THE WEST TOO. THESE ARE OVER EASTERN NORTH DAKOTA...NE MONTANA...NORTH CENTRAL MONTANA AND NE WASHINGTON. NONE OF THESE HAVE ANY TRUE SURFACE REFLECTION OTHER THAN RESULTING IN BROAD LOW PRESSURE ACROSS MUCH OF THE NORTHERN PLAINS. ALSO TO NOTE...FAIRLY WARM AIR EXISTS ALOFT ACROSS MUCH OF THE NORTHERN U.S....WITH 850MB TEMPS ON THE 12Z RAOBS BETWEEN 19-23C FROM GREEN BAY WESTWARD INTO MONTANA. THIS WARM AIR ALOFT IS WHAT ALSO HELPED TEMPERATURES CLIMB INTO THE 80S. TONIGHT...UPPER LEVEL FLOW IS PROGGED TO TURN SLIGHTLY MORE ZONAL THROUGH THE COURSE OF THE NIGHT. SO ALTHOUGH THE COLD FRONT/TROUGH IS MAKING ITS WAY SOUTH THROUGH UPPER MICHIGAN...IT IS EXPECTED TO STALL PROBABLY IN THE VICINITY OF GREEN BAY THIS EVENING. NONETHELESS...WITH THE FRONT MOVING OUT OF THE CWA...MUCH OF THE CONVECTION OCCURRING ACROSS SOUTHERN UPPER MICHIGAN WILL END THIS EVENING. MODELS THEN SHOW A SLIGHT DRIFT BACK TO THE NORTH WITH THE TROUGH OVERNIGHT...SO A CONCERN WOULD EXIST ABOUT ELEVATED PRECIPITATION DEVELOPING. LOOKING AT 305-310K SURFACES...THERE IS SOME WEAK LIFT PRESENT...HOWEVER CONDENSATION PRESSURE DEFICITS ARE ON THE HIGH SIDE (150-200MB)...AT LEAST OVER UPPER MICHIGAN. IN FACT...MODEL QPF FIELDS FROM THE NAM...GFS...13 KM EXPERIMENTAL RUC AND A LOCAL WRF RUN HERE ALL INDICATE DRY CONDITIONS. BETTER ISENTROPIC LIFT WITH LOWER PRESSURE DEFICITS ARE IN WISCONSIN...SO SOME SHOWERS MAY POP UP OVERNIGHT IN WISCONSIN PERHAPS ALONG OR SOUTH OF THE TROUGH AS THE GFS INDICATES. DECREASE WINDS TONIGHT COMBINED WITH SOME DECREASE IN CLOUD COVER SHOULD ALLOW TEMPERATURES TO DROP TO THE DEWPOINTS. HAVE DECIDED TO INSERT SOME PATCHY FOG OVERNIGHT ACROSS THE CENTRAL AND EASTERN U.P. DUE TO THE RAIN THAT HAS OCCURRED TODAY. TUESDAY...WARM ADVECTION IS PROGGED TO CONTINUE DURING THE MORNING...PUSHING THE SURFACE TROUGH BACK INTO THE CWA. THIS WARM ADVECTION MAY RESULT IN SOME ELEVATED PRECIPITATION IN THE MORNING AS THE GFS SUGGESTS...BUT CONFIDENCE IN THIS OCCURRING IS NOT HIGH GIVEN THAT THE NAM AND UKMET ARE DRY. NONETHELESS...AT LEAST SOME SLIGHT CHANCE POPS ARE REQUIRED SINCE MODELS INDICATE THE SHRTWV OVER NE MONTANA MAY BE MOVING OVER. BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY IN THE INTERIOR...WILL COME IN THE AFTERNOON AS TEMPERATURES HEAT UP AND LAKE BREEZES FORM. HAVE RAISED POPS TO 50 IN THE INTERIOR. LOOKS LIKE THE KEWEENAW PENINSULA WILL BE IN THE STABLE MARINE AIR SO HAVE REMOVE POPS FOR THERE IN THE AFTERNOON. AS FOR THE TEMPERATURES...MODELS SUGGEST 850MB TEMPS OF 18-20C...SIMILAR TO TODAY. THEREFORE HIGHS SHOULD BE SIMILAR TOO. SEVERE WEATHER POTENTIAL LOOKS MARGINAL SINCE 0-6KM SHEAR IS ONLY 15-20 KT (MAINLY PULSE STORMS). HOWEVER...WITH MLCAPE VALUES OF 1000-2000 J/KG AND WET BULB ZERO HEIGHTS REMAINING LOW (11000 FT WEST TO 9000 FT EAST)...SOME CONCERN EXISTS FOR HAIL. SPC DAY 2 OUTLOOK ONLY HAS 5 PERCENT PROBABILITIES OVER THE U.P. AND THIS SEEMS REASONABLE. TUESDAY NIGHT INTO WEDNESDAY NIGHT...CONVECTION THROUGH THIS PERIOD IS HARD TO TIME AND FIGURE OUT AS MODELS ARE SUGGESTING NEARLY ZONAL FLOW FROM THE NORTHERN INTERMOUNTAIN STATES ACROSS INTO UPPER MICHIGAN. THIS PATTERN WOULD FAVOR WEAK SHRTWVS CROSSING THE AREA AND ANY OF THEM COULD RESULT IN BRIEF LOW LEVEL JET INCREASES TO PRODUCE CONVECTION AT NIGHT...OR BRING COOLER AIR ALOFT DURING THE DAY WHICH WOULD COMBINE WITH LAKE BREEZES AND RESULT IN DIURNAL AFTERNOON CONVECTION. BECAUSE OF THE UNCERTAINTY REGARDING TIMING OF THE SHRTWVS...HAVE DECIDED TO MAINTAIN A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. DID KEEP POPS SLIGHTLY HIGHER DURING THE AFTERNOON AND EVENING OF WEDNESDAY BECAUSE OF LAKE BREEZES HELPING CONVECTION. FREEZING AND WET-BULB ZERO HEIGHTS ARE HIGHER DURING THIS PERIOD...SO THE SEVERE WEATHER THREAT MAY NOT BE AS HIGH. LITTLE CHANGE IS PROGGED WITH REGARDS TO BOTH 850MB TEMPS AND DEWPOINTS...SO READINGS BOTH ON TEMPS AND DEWPOINTS SHOULD BE SIMILAR TO TUESDAY. THURSDAY INTO THURSDAY NIGHT...GFS/UKMET/ECMWF ALL SHOW A SHRTWV TROUGH DROPPING SOUTH OUT OF CENTRAL CANADA INTO THE GREAT LAKES REGION. THIS TROUGH WILL BE ASSOCIATED WITH A SURFACE COLD FRONT...EXPECTED OVER WESTERN MN THURSDAY MORNING AND MOVING ACROSS THE U.P. THURSDAY NIGHT. IT IS LIKELY MORE DIURNAL SHOWERS AND THUNDERSTORMS WILL FORM ON THURSDAY ALONG LAKE BREEZE BOUNDARIES SINCE THE PRESSURE GRADIENT WILL BE RELATIVELY WEAK. WE SHOULD ALSO SEE SOME STORMS FIRE ALONG THE COLD FRONT...MOVING INTO THE CWA THURSDAY NIGHT. THEREFORE CHANCES OF SHOWERS AND THUNDERSTORMS PERSIST FOR UPPER MICHIGAN. 850MB TEMPS ARE AGAIN NOT EXPECTED TO BE ALL THAT DIFFERENT THAN THE PAST FEW DAYS...SO LITTLE CHANGE IS EXPECTED REGARDING HIGH TEMPERATURES BETWEEN WEDNESDAY AND THURSDAY. RELATIVELY HIGH DEWPOINTS THURSDAY NIGHT WILL HELP KEEP LOW TEMPERATURES UP...SIMILAR TO THE PREVIOUS FEW NIGHTS. EXTENDED (FRIDAY THROUGH MONDAY)...MODEL AGREEMENT BETWEEN OPERATIONAL MODELS AND 00Z GFS ENSEMBLES IS NOT AS GREAT TODAY... WITH VARYING DEGREES ON HOW MUCH TROUGHING DEVELOPS NEAR/ALONG THE PACIFIC NW COAST AND OVER SOUTHEAST CANADA INTO NEW ENGLAND. BOTH OF THESE FACTOR IN HOW MUCH RIDGING BUILDS TOWARDS THE GREAT LAKES REGION DURING THE WEEKEND INTO EARLY NEXT WEEK. OVERALL MODELS ARE IN GOOD AGREEMENT ON FRIDAY...INDICATING A TROUGH DROPPING THROUGH WESTERN BRITISH COLUMBIA...RESULTING IN SOME RIDGING DOWNSTREAM IN SOUTH CENTRAL CANADA WHILE HIGH PRESSURE BUILDS INTO UPPER MICHIGAN AHEAD OF THIS AT THE SURFACE. AFTER FRIDAY...THE 00Z ECMWF BECOMES VERY AMPLIFIED WITH THE FLOW...DEVELOPING A 540 DAM LOW NEAR JAMES BAY BY 00Z SUNDAY. NO OTHER MODEL SHOWS THIS STRONG OF A TROUGH... NOR DOES ITS PREVIOUS RUN...SO HAVE CONSIDERED IT AN OUTLIER. NEW 12Z ECMWF LOOKS MORE LIKE THE 00Z UKMET. PREFER A SOLUTION MORE ALONG THE LINES OF THE 00Z UKMET/06Z GFS WHICH KEEPS UPPER MICHIGAN UNDER THE INFLUENCE OF THE HIGH PRESSURE AREA AS THE RIDGE OVER SOUTH CENTRAL CANADA IS PUSHED EAST SLIGHTLY. THIS IS SUPPORTED TOO BY THE 00Z GFS ENSEMBLES AND SOMEWHAT BY THE 00Z CANADIAN. SO A DRY WEATHER FORECAST INTO SATURDAY STILL SEEMS GOOD. THE UPPER TROUGH NEAR/OVER THE PACIFIC NW IS THEN SHOWN BY MOST MODELS TO BECOME LESS AMPLIFIED...AND BECOME A MORE BROAD TROUGH FROM THE GULF OF ALASKA INTO SW CANADA. THIS WILL RESULT IN PUSHING RIDGING OVER THE NORTHERN PLAINS/UPPER MISSISSIPPI VALLEY INTO THE GREAT LAKES...WITH TROUGHING FURTHER DOWNSTREAM IN THE CANADIAN MARITIMES. AS THIS RIDGE BUILDS TOWARDS UPPER MICHIGAN...WARM ADVECTION MAY RESULT IN CLUSTERS OF SHOWERS AND THUNDERSTORMS MOVING OUT OF NORTHERN MINNESOTA INTO UPPER MICHIGAN BOTH SUNDAY AND MONDAY...ASSUMING WE STAY ON THE EDGE OF THE CAP WHICH SHOULD BE FIRMLY IN PLACE ACROSS MUCH OF THE PLAINS. SPC DAY 4-8 OUTLOOK MAINTAINS A RISK FOR SEVERE WEATHER FOR THE SUNDAY TIMEFRAME. 06Z GFS INDICATES SOME PRETTY WARM AIR HEADING TOWARDS THE CWA...WITH 850MB TEMPS OF 18-20C ON SUNDAY AND AROUND 20C FOR MONDAY. IF PLENTY OF SUNSHINE CAN OCCUR...HIGHS WOULD TOP OUT AROUND 90 AWAY FROM LAKE MICHIGAN. HOWEVER...CONVECTION CHANCES AND UNCERTAINTY THAT FAR OUT RESULTS IN KEEPING TEMPERATURES LOWER THAN THAT...BUT STILL ABOVE NORMAL. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 306 PM EDT MON JUL 24 2006 .SYNOPSIS... UPPER LEVEL TROUGH OVER THE NORTHERN GREAT LAKES REGION AND NORTHEAST COASTLINE...WITH A WEAK RIDGE OVERHEAD. A SHORTWAVE IS MOVING INTO LOWER MI...BUT CONVECTION IS HAVING A HARD TIME GETTING GOING AS SHORTWAVE MOVES INTO THE RIDGE. OUT WEST...A LARGE FOUR CORNERS HIGH CAN BE FOUND IN THE WESTERN US WITH LOTS OF MOISTURE AND DAILY CONVECTION. SEVERAL SHORTWAVES ARE ROTATING AROUND THIS HIGH...WITH SOME FEATURES OF INTEREST MOVING TOWARD THE DAKOTAS AND MONTANA. THESE WILL BE POSSIBLE PLAYERS FOR WEDNESDAY AND THURSDAY. AT THE SURFACE...A RIDGE IS OVERHEAD WITH SOUTHERLY FLOW UPSTREAM...ALTHOUGH NOT CARRYING MUCH MOISTURE AT THIS TIME AS DEWPOINTS IN THE OHIO VALLEY ARE NOT RESPONDING TOO MUCH. && .SHORT TERM /TONIGHT THROUGH THURSDAY/... TONIGHT...SHORTWAVE UPSTREAM IN MI WILL MOSTLY PASS BY TO OUR NORTH. CURRENTLY...CONVECTION STRUGGLING IN MI THIS AFTERNOON AS SHORTWAVE MOVES INTO RIDGE. NAM-WRF TRIES TO REGENERATE SOME PRECIP LATER THIS AFTERNOON...BUT IT MAY BE A BIT OVERDONE AS ITS LOW LEVEL JET APPEARS TOO STRONG WHEN COMPARED TO RUC ANALYSIS DATA. REGARDLESS...PRECIP AMOUNTS ARE PRETTY LOW...ONLY A FEW HUNDREDTHS TO A TENTH OR SO IN SOUTHERN ONTARIO BY 12Z TUESDAY. PRECIP MAY SKIRT THE NORTH SIDE OF LAKE ONTARIO OVERNIGHT. WILL LEAVE ALL AREAS DRY WITH CLOUDS CLOSER TO LAKE ONTARIO...AND PATCHY FOG LATE IN THE VALLEY AREAS WITHIN THE SOUTHERN TIER IN FINGER LAKES REGIONS. TUESDAY THROUGH THURSDAY...NO REAL CHANGE TO FORECAST...WITH A GENERAL BROADBRUSH OF A CHANCE OF SHOWERS AND THUNDERSTORMS...HIGHEST OVER THE EASTERN LAKE ONTARIO REGION ON TUESDAY. INITIALLY...WILL HAVE TO DEAL WITH A SAGGING TROUGH CURRENTLY OVER THE NORTHERN GREAT LAKES REGION. MODELS DO NOT APPEAR TO HAVE A GOOD HANDLE ON SHORTWAVE MOVING INTO WI AT THIS TIME...AND THEY WASH OUT A FEW VORT CENTERS READILY SEEN IN WATER VAPOR IMAGERY NEAR WESTERN IL AND OVER LAKE MICHIGAN. ON WEDNESDAY AND THURSDAY...SHORTWAVE ENERGY CURRENTLY NEAR THE DAKOTAS WILL BE APPROACHING. BOTH OPERATIONAL MODELS PICK UP ON THIS TO SOME DEGREE SO FORECAST CONFIDENCE EVER SO SLIGHTLY HIGHER. WILL BUMP PROBABILITY OF PRECIPITATION UP FROM ABOUT 30 PERCENT IN WESTERN NY TUESDAY TO A WHOPPING 40 PERCENT ON WEDNESDAY. MORE SHORTWAVES FOR THURSDAY FOR A CONTINUED CHANCE OF PRECIPITATION AND THUNDERSTORMS. CONFIDENCE LOW ON TIMING ANY FEATURES. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... A COLD FRONT WILL APPROACH THE AREA ON FRIDAY AS AN UPPER LEVEL TROUGH MOVES THROUGH...BUT IT MAY NEVER QUITE GET THROUGH WESTERN NY. THERE IS VERY LITTLE EVIDENCE OF IT ALOFT BY FRIDAY NIGHT. THE FOUR CORNERS HIGH WILL MOVE INTO THE PLAINS STATES OVER THE WEEKEND. WILL FOLLOW HPC GUIDANCE FOR THE EXTENDED...ONLY NOTING THAT THE GFS DOES HAVE A FEW NICE SHORTWAVES MOVING OVER THE RIDGE ON SUNDAY AND MONDAY. THESE WOULD BE MCS-LIKE EVENTS. OF COURSE...ITS TOO FAR OUT TO TIME AND PLACE SUCH EVENTS. && .AVIATION... VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. HIGH PRESSURE PRIDED ACROSS THE AREA WILL KEEP FAIR WEATHER ACROSS THE AREA THROUGH THIS EVENING. ANY DIURNAL CUMULUS WILL DISSIPATE THIS EVENING. WARM AIR ADVECTION MID AND UPPER LEVEL CLOUDINESS ACROSS THE CENTRAL AND UPPER GREAT LAKES WILL TRANSLATE EASTWARD AND SPREAD OVER THE AREA TONIGHT. OPERATIONAL MODELS SUGGESTING A FEW SHOWERS MAY REACH THE AREA BY THE END OF THE TAF PERIOD AS THE SHORTWAVE PRODUCING CONVECTION ACROSS WESTERN GREAT LAKES WEAKEN ACROSS NEW YORK STATE TUESDAY MORNING. THIS HAS BEEN SUGGESTING AT ALL TAF SITES BY THE END OF THE PERIOD. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...ZAFF SHORT TERM...ZAFF LONG TERM...ZAFF AVIATION...TMA ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 302 PM CDT MON JUL 24 2006 .DISCUSSION... FORECAST DISCUSSION REMAINS CENTERED ON ACTIVE WEATHER PATTERN THROUGH MID WEEK. IN THE SHORT TERM...FRONTAL BOUNDARY AS ADVERTISED BY NGM/WRF- NAM/GFS/RUC PROGS HAS SETTLED ACROSS NORTHERN WISCONSIN. WEATHER PATTERN EVOLUTION THROUGH WEDNESDAY BY PROGS WILL RESULT IN AN ACTIVE...WET AND UNSETTLED PERIOD OVER CWA. POTENTIAL EXISTS FOR MODERATE TO HEAVY RAINFALL ACROSS CWA THROUGH WEDNESDAY NIGHT ALONG WITH PERIODS OF SEVERE WEATHER. POSITION OF FRONTAL BOUNDARY HIGHLY DEPENDENT ON STRENGTH AND DURATION OF CONVECTION ALONG IT. FRONT BECOMES DIFFUSE TUESDAY AS PROGGED CONVECTION YIELDS DIFFERING PRESSURE PATTERNS. HOWEVER STEADY STREAM OF LOW LEVEL MOIST WARM AND UNSTABLE AIR WILL CONTINUE TO FEED INTO CWA DESPITE POSITION OF BOUNDARY AND AN EXTENDED PERIOD OF CONVECTION IS EXPECTED. HAVE BOOSTED RAIN CHANCES THROUGH WEDNESDAY BUT UNABLE TO FORECAST ANY EXTENDED PERIODS WHEN CONVECTION WOULD BE ABSENT LONG ENOUGH TO REMOVE RAIN CHANCES FROM FORECAST. IN THE LONG TERM...GFS SHOWING SIGNS OF BACKING OFF ON DRY WEEKEND AS PREVIOUSLY PROGGED HIGH PRESSURE QUITE WEAK WITH A STRONG LOW PRESSURE DEVELOPING OVER PLAINS STATES. THIS MAINTAINS MOIST SOUTHERLY FLOW AND COULD RESULT IN SCATTERED CONVECTION. WILL AWAIT FURTHER PROG RUNS BEFORE CHANGING FORECAST FOR NOW. && .MKX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ZAJDEL wi