AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EUREKA CA 345 PM PDT MON APR 18 2005 .SYNOPSIS...MOSTLY FAIR SKIES WILL PERSIST ACROSS NORTHWEST CALIFORNIA TONIGHT AND TUESDAY...AS HIGH PRESSURE REMAINS NEARLY STATIONARY OFFSHORE...WHILE LOW PRESSURE CONTINUES OVER THE INLAND AREAS. INTERACTION BETWEEN PRESSURE SYSTEMS WILL KEEP BREEZY CONDITIONS ACROSS THE REGION...WITH STRONGER WINDS AT THE COAST. WINDS ARE EXPECTED TO EASE SOMEWHAT BY MIDWEEK. && .DISCUSSION...THE UPPER LOW OVER GREAT BASIN WILL REMAIN OVER THE AREA FOR THE NEXT FEW DAYS. THE COLD POCKET ASSOCIATED WITH THIS LOW IS CURRENTLY PRODUCING ISOLATED RAINSHOWERS OVER NORTHERN PORTION OF CWA AND OREGON THAT WILL CONTINUE THROUGH THIS EVENING. THE STRONG RIDGE OVER THE EAST PAC WILL BEGIN TO WEAKEN TONIGHT AS AN UPPER LOW DEVELOPS NEAR 40N 140W. THIS LOW IS PROGGED TO DRIFT SOUTH AND BECOME CUTOFF THURSDAY MORNING. WITH THE RIDGE STILL HANGING IN AND THE CUTOFF LOW SOUTH FORMING A BLOCKING PATTERN...ENTIRE CWA LOOKS TO CONTINUE IN A DRY PATTERN THROUGH FRIDAY. ALL MODELS IN PRETTY GOOD AGREEMENT WITH THIS SCENARIO. THE PATTERN BECOMES MORE INTERESTING SATURDAY AND SUNDAY. CURRENT GFS ENSEMBLE INDICATING THE GREAT BASIN LOW DISSIPATING BY EARLY SAT MORNING...WITH THE CUTOFF LOW BEGINNING TO DRIFT NORTH BRINGING THE CWA INTO A WETTER PATTERN. PREVIOUS RUNS INDICATED A TOTALLY DIFFERENT PATTERN. BASED ON THE DIFFICULTY MODELS HAVE WITH CUTOFF LOWS...NOT VERY CONFIDENT WITH CURRENT SOLUTION...HOWEVER...LOOKS REASONABLE TO AT LEAST MENTION SLIGHT CHANCE OF SHOWERS SUNDAY AND MONDAY. && .MARINE...STRONG LOCAL N FETCH UNDERWAY. ETA20 RUC40 AND GFS80 ALL HINTING AT 30+ KNOTS OF SUSTAINED WIND OVER PORTIONS OF THE CAPE MENDOCINO TO PT ARENA MARINE ZONE THIS EVENING...HENCE WILL KEEP GALE WARNING FLAGS RAISED OVERNIGHT OVER THE SOUTHERN WATERS AND MAINTAIN SMALL CRAFT ADVISORIES NORTH OF CAPE MENDOCINO. WIND WAVE COMPONENT OF SPECTRUM SHOULD ABATE SOMEWHAT MID WEEK IF LOWER PRES FORMS NEAR 130W 40N REMOVING SOME PUNCH FROM RESIDENT SFC HIGH. SWELL FRONT FROM CYCLONE SOUTH OF ALEUTIAN CHAIN WILL DIRECT LONGER PERIOD ENERGY INTO THE LOCAL WATERS WEDNESDAY MORNING BUT SWELL HGT NOT MUCH DIFFERENT FROM RESIDENT SIGNIFICANT WAVE THEN SO WAVE STEEPNESS WILL BE THE MAIN SEA STATE CHANGE THEN AS WINDS EASE UP. LONGER RANGE GETS COMPLICATED BUT INCREASING N WINDS LATE IN THE WEEK WAS FAVORED AS HIGH PRES BUILDS INTO THE PAC NW AND TEMPS WARM OVER THE INTERIOR. && .EKA WATCHES/WARNINGS/ADVISORIES... PT ST GEORGE TO CAPE MENDOCINO OUT TO 60 NM SMALL CRAFT ADVISORY FOR WINDS AND HAZARDOUS SEAS TONIGHT THROUGH TUE NIGHT CAPE MENDOCINO TO PT ARENA OUT TO 60 NM GALE WARNING TONIGHT SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS TONIGHT THROUGH TUE NIGHT $$ SYNOPSIS: ASHFORD DISCUSSION: KLEESCHULTE MARINE: COLBY ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 905 PM EDT MON APR 18 2005 .DISCUSSION... CURRENT...SKIES HAVE CLEARED AFTER SOME LATE AFTN CI STREAMERS DPEARTED THE AREA. LOOKING UPSTREAM...RUC ANLYS SHOWS LARGE SWATH OF DIVG OVER THE WRN AND CTRL GOMEX...ASCD WITH DIVGT LEFT FRONT QUAD OF SUBTROP JET...WHICH IS PRODUCING PLENTY OF CI/CS. AT THE SFC... NE-E WINDS ARE ~8-10MPH WITH M-U60 TEMPS AND L-M50 TD'S AREAWIDE. FCST...SKIES/TEMPS/WINDS LOOK FINE IN THE FCST. GIVEN CURRENT TD'S ...WILL LIKELY EXPAND MIN TEMP RANGE HALF A CAT OVER THE CTRL/SOUTH TO INCLUDE U50S. && .MARINE...WINDS/SEAS LOOK RIGHT ON. NO CHGS NEEDED. && .MLB WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY FOR SEAS FLAGLER BEACH - JUPITER INLET. && $$ CRISTALDI/BRAGAW fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1245 PM EST MON APR 18 2005 .AVIATION... SCATTERED DIURNAL CU THIS AFTERNOON AND WITH STEEP LOW LEVEL LAPSE RATES NEAR 10C/KM SHOULD CONTINUE TO SEE SOME HIGHER GUSTS MIX DOWN...ESPECIALLY AT KSBN WITH L2 MOMENTUM TRANSFER WINDS AROUND 20KTS. SOME UPSTREAM FOG THIS MORNING AND WILL AGAIN BRING POSSIBLE MVFR CONDITIONS NEAR SUNRISE...BUT RELEGATE TO TEMPO GROUP FOR NOW. BETTER MIXING/STRONGER WIND PROFILE TUESDAY WITH GUSTS AT BOTH SITES. && .SHORT TERM... THE MID LEVEL CUMULUS WILL BE AROUND TODAY WITH THAT FRONT IN THE AREA. A LITTLE BIT OF LIGHT RAIN/SPRINKLES IS IN THE AREA AND IS VERY ISOLATED IN NATURE. THE CHANCE FOR ANY LIGHT RAIN/SPRINKLES TODAY IS SMALL BUT SOME THINGS THAT COULD CREATE THE LIGHT RAIN/SPRINKLES TODAY IS THE FRONT IN THE AREA AND ETA IN BUFKIT IS SHOWING SOME LAPSE RATES FOR LIFT WITH A LITTLE BIT OF MOISTURE IN THE MID LEVELS. WATCHING RADAR TRENDS FROM HERE TO WISCONSIN THE ISOLATED RAIN APPEARS TO BE MOVING EAST. SO WITH THE RAIN APPEARING TO DISSIPATE AND SUCH SMALL CHANCES TODAY WILL STICK WITH DRY FOR TODAY. IF ANY RAIN DOES POP UP TODAY IN THAT MID LEVEL CUMULUS, IT WILL BE ISOLATED IN NATURE. ALSO THIS AFTERNOON THAT FRONT WILL LIFT NORTHEASTWARD OUT OF THE AREA WHICH SHOULD MOVE THE BEST LIFT OUT OF OUR CWA. LOOKING AT RUC13 IT LOOKS LIKE A LAKE BREEZE COULD SET UP TODAY ALONG THE LAKE MICHIGAN LAKE SHORE, SO HAVE PUT THAT IN FOR THIS AFTERNOON AS WELL AS LOWERED LAND HIGH TEMPERATURES NEAR LAKE MICHIGAN TODAY. NO CHANGES TO TONIGHT. STILL EXPECTING A DRY NIGHT IN THE LOWER 50S. && .LONG TERM... CURRENT LONG TERM FORECAST LOOKS GOOD AND ONLY SOME MINOR TWEEKS. HAVE ADDED A SMALL CHANCE OF TSRA TO NORTHERN AREAS FOR LATE TUE NIGHT AS SHORT WAVE ENERGY RIDES OVER TOP OF FLAT RIDGE. WEAK MID LEVEL OMEGA ACROSS NORTHERN AREAS WITH THIS FEATURE AND LOW LEVEL FRONTOGENETICAL FORCING INCREASES TOWARD 12Z. SURFACE AND LOW LEVEL MOISTURE REMAINS LIMITED BUT MID LEVEL INSTABILITY INCREASES A BIT. TOTAL TOTALS APPROACH 50 AND K INDEX TO 30 BY 12Z. PROXIMITY OF SURFACE FRONT IN THE NORTHWEST LEADS TO SOME INCREASED LOW LEVEL CONVERGENCE AS WELL. OTHERWISE LEFT MAJORITY OF LONG TERM FORECAST INTACT. GENERAL TREND OF COOLER TEMPERATURES BEHIND FROPA STILL REASONABLE AND GFS/MEX INDICATING EVEN COOLER TEMPERATURES POSSIBLE. && .IWX WATCHES/WARNINGS/ADVISORIES... .IN...NONE. .MI...NONE. .OH...NONE. && $$ in AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE GOODLAND KS 825 PM MDT MON APR 18 2005 .DISCUSSION...A MINOR UPDATE TO BE COMING OUT SHORTLY. DRYLINE/HIGHER DEWPOINTS RETREATING TO THE WEST. MODELS HAVING A HARD TIME WITH SURFACE PATTERN/LOW LEVEL MOISTURE. MODELS NOT STRONG ENOUGH/FAR ENOUGH WEST WITH LEE TROUGH AND LOW LEVEL MOISTURE. UPDATED DEWPOINTS AND WINDS WITH RUC WHICH LOOKED TO BE CLOSEST. AS A RESULT RAISED MINS SLIGHTLY IN EAST WHERE DEWPOINTS WILL STAY A LITTLE HIGHER. ALSO TWEEKED HOURLY TEMPERATURES THROUGH 12Z. CURRENT FOG FORECAST LOOKS RIGHT ON BASED ON LATEST MODEL DATA. && .GLD WATCHES/WARNINGS/ADVISORIES... .KS...NONE. .NE...NONE. .CO...NONE. && $$ BULLER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI ISSUED BY NATIONAL WEATHER SERVICE GAYLORD MI 1255 PM EDT MON APR 18 2005 .UPDATE...SCATTERED CONVECTION OVER WRN UPPER HAS BEEN SLOW TO DISSIPATE...WITH A FEW SHOWERS AND EVEN THUNDERSTORMS STILL LINGERING. WILL CONTINUE WIDELY SCATTERED SHOWERS/STORMS IN THESE AREAS THROUGH THE AFTERNOON. LATEST NAM SOUNDINGS -- VALID 21 UTC -- SHOWS INCREASING SURFACE BASED INSTABILITY...WITH CAPES IN EXCESS OF 1000 J/KG. THOUGH SURFACE DEW POINTS (AND THEREFORE INSTABILITY) ARE LIKELY A BIT OVERDONE...THIS WOULD STILL SUPPORT KEEPING SOME CONVECTION GOING THROUGH LATE AFTERNOON. OTHER CHANGES TO GOING FORECAST/GRIDS MINOR. SMITH && .PREV DISCUSSION...ISSUED 330 AM MON APR 18 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW BLDG UPR RDG FM THE MID MS VALLEY NWD THRU THE NW GRT LKS AND INTO NW ONTARIO BTWN DEEPENING TROFS IN THE PAC NW AND IN SE CAN/NEW ENGLAND. HUDSON BAY HI PRES CENTERED JUST S OF JAMES BAY...AND DRY ACYC FLOW ARND THIS FEATURE IS THE DOMINANT INFLUENCE ON THE WX THIS MRNG OVER THE UPR GRT LKS. 00Z GRB/APX SDNGS SHOW A DRY/STABLE AIRMASS (KINX -1/3 AT GRB/APX) IN PLACE. BUT SOME SCT SHRA/TSRA HAVE DVLPD TO THE SW ACRS SRN MN/SW WI ALG AXIS OF HIER LLVL MSTR/H85 DWPT (00Z PWAT AT MPX UP TO 0.90 INCH AND H85 DWPT 7C) AND IN ADVANCE OF SFC TROFFING STRETCHING SEWD FM THE NRN PLAINS INTO THE MID MS VALLEY AND WEAK SHRTWV RUC ANALYSIS SHOWS MOVING TOWARD SW MN. SOME HI CLD AHEAD OF THIS FEATURE HAVE MOVED INTO THE WRN CWA. PRES GRADIENT BEGINNING TO SHARPEN OVER MN IN ADVANCE OF PRES FALLS IN THE WRN PLAINS TO THE E OF DEEPENING PAC NW TROF...WHERE 12HR H3 HGT FALLS EXCEED 100M OVER THE NRN ROCKIES. ANOTHER SHRTWV MOVING SLOWLY NEWD THRU THE SRN PLAINS...WHICH HAS TRIGGERED SOME TSRA THERE DESPITE A RATHER SLOW RETURN OF GLFMEX MSTR (H85 DWPTS STILL ONLY 5-8C IN THE SCNTRL PLAINS). MAIN FCST CONCERNS TDAY ARE SHRA CHCS ACRS THE W ASSOCIATED WITH WEAK SHRTWV/MSTR IN SW MN AND TEMPS. FOCUS THEN SHIFTS TO TIMING/ IMPACT OF TROF IN THE PAC NW AS WELL AS SHRTWV MOVING NE THRU THE SRN PLAINS. FOR TDAY...00Z NAM SHOWS VEERING H85 FLOW TO SW ADVECTING HIER H85 DWPTS TO THE SW ACRS THE WRN ZNS THIS MRNG AS SHRTWV IN SW MN DRIFTS SLOWLY NNEWD THRU MN...WITH SOME DPVA/H85-5 QVECTOR CVNGC BRUSHING THE WRN ZNS THIS MRNG. NAM FCST SDNG FOR IWD SHOWS MUCAPE UP TO 570J/KG AT 12Z WITH A SMALL -20J/KG CIN LIFTING PARCEL FM H85. AXIS OF RATHER SHARP H85-7 FRONTOGENESIS PROGGED TO DRIFT ACRS THE AREA AT THE SAME TIME...AND AGEOSTROPHIC CIRCULATION WL LIKELY BE ENUF TO ERODE SML CAP. SO HAVE OPTED TO ADD SCT -TSRA OVER THE WRN ZNS THIS MRNG BEFORE AXIS OF HIER H85 DWPT/LOWER SSI/FRONTOGENESIS PROGGED TO DRIFT NE OVER LK SUP IN THE AFTN. OTRW... DAY SHOULD TURN OUT MOSUNNY AND QUITE WARM AS ACYC SW FLOW BECOMES ESTABLISHED IN THE AFTN. GFS HAS COME ARND TO EARLIER IDEA OF PUSHING H85 TEMP UP TO 14C OVER THE W LATE IN THE DAY...AND DEEP MIXING TO H75 ON NAM FCST SDNG FOR IWD THIS AFTN YIELDS TMAX OF 82F. ALTHOUGH MODIFIED NAM SDNG FOR IWD AT 21Z FOR T/TD 82/47 SHOWS CAPE UP TO 865J/KG WITH LTL CIN...DECIDED TO RETAIN DRY FCST WITH ACYC H85 FLOW AND ABSENCE OF BNDRY. ALTHOUGH THERE WL BE A LK MI BREEZE BNDRY FARTHER E...LLVL AIR THERE WL BE DRIER THAN FARTHER W. FA WL BE IN THE WARM SECTOR TNGT WITH SW ACYC FLOW DOMINATING. NAM FCST SDNGS SHOW A BONE DRY AIRMASS IN PLACE. EVEN THOUGH SRN PLAINS SHRTWV FCST TO DRIFT INTO IA BY 12Z TUE MIGHT CAUSE SOME HI CLD TO DRIFT INTO THE FA OVERNGT...SKIES SHOULD BE MOCLR. BUT NAM/GFS FCST H925 WINDS TO 30KT SHOULD KEEP TEMPS FM FALLING TOO FAR...AND HAVE TENDED TOWARD THE HI SIDE OF MOS GUIDANCE FOR TMIN. MODEL CONSENSUS SHOWS SFC FNT IN ADVANCE OF WRN TROF PUSHING TO NEAR WRN LK SUP BY 12Z. BUT ATMOSPHERE APPEARS TOO DRY/CAPPED IN ADVANCE OF BDNRY FOR ANY PRE FNT CNVCTN...ESPECIALLY CONSIDERING BETTER UPR DVGC/DEEP LYR H85-3 QVECTOR CNVGC/SHARP FRONTOGENESIS ON THE COOL SIDE OF BNDRY. WL MAINTAIN GOING DRY FCST. SFC FNT FCST TO PUSH INTO THE CNTRL FA BY 00Z WED AS UPR FLOW BECOMES MORE SPLIT WITH WLY NRN BRANCH FLOW ACRS SRN CAN LEAVING CUTOFF H5 LO OVER THE CNTRL ROCKIES. MODELS IN RSNBL CONSENSUS SHOWING SRN PLAINS SHRTWV DRIFTING ACRS WI ON TUE...WITH AXIS OF PWAT AOA 1.00 INCH REACHING INTO UPR MI. COMBINATION OF VIGOROUS H85-5 QVECTOR CNVGC...SOME UPR DVGC IN RRQ OF UPR JET MAX PASSING ACRS ONTARIO...AND RATHER STRONG FRONTOGENESIS/LLVL CNVGC ASSOCIATED WITH ARRIVING FAIRLY SHARP BNDRY WARRANTS CONTINUED LIKELY POPS FOR AT LEAST PART OF THE FA INTO TUE EVNG. ARRIVAL OF FNT IN THE AFTN DURING DIURNAL MAX HTG ALSO FVRBL FOR SOME TSRA DVLPMNT...BUT FCST NEARLY MOIST ADIABATIC LAPSE RATES/LIMITED NCAPE/RELATIVELY LGT WINDS ALF AND WEAK SHEAR WL MITIGATE SVR THREAT. MODELS HAVE TRENDED FASTER WITH FCST UPR LVL DRYING ON TUE NGT WITH MORE WNW FLOW ALF ACRS SRN CAN...SO HAVE CUT OR ENDED POPS FASTER AS COLD FNT PUSHES FARTHER S FASTER WITH BLDG RDG OVER SCNTRL CAN UNDER MORE NW FLOW ALF. THEN DRY ON WED WITH MUCH DRIER/STABLE AIRMASS MOVING IN PER NAM/GFS FCST SDNGS (GFS/NAM FCST KINX AT MQT AT 12Z WED -18/-17). WED WL BE A MUCH COOLER DAY WITH SHARP PRES GRADIENT/STIFF NLY FLOW OFF LK SUP AND GFS/NAM FCST H85 TEMPS ARND 0C. COORDINATED WITH APX. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1040 AM EDT MON APR 18 2005 .UPDATED... I WILL UPDATE THE ZONES TO PUT SCT SHOWERS AND ISOLATED THUNDERSTORMS IN THE FORECAST TILL MID AFTERNOON MOSTLY NEAR AND NORTH OF INTERSTATE 96 AND EAST OF US-131. I WILL KEEP THE ISOLATED WORDING FOR SHOWERS SOUTH OF INTERSTATE 96. WINDS AND TEMP FORECAST LOOKS FINE. BASED ON TAMDAR SOUNDING TIME LOOP NEAR GRR AND COMPARING THAT TO LAPS...RUC AND ETA40 SOUNDING... SEEMS THERE IS SOME MID LEVEL INSTABILITY NEAR THE WARM FRONT AT 14Z. THTE ON THE RUC DECREASES WITH HEIGHT TO NEAR 10000 FT THROUGH THE AFTERNOON. IF ONE HEATS A PARCEL TO 78F WITH A DEW POINT NEAR 48F AT 21Z ONE GETS AN EQUILIBRIUM LEVEL NEAR 24000 BUT A VERY NARROW CAPE OF AROUND 200 J/KG. ECHOES GETTING OVER 19000FT WILL BE TALL ENOUGH FOR LIGHTNING THIS AFTERNOON. THERE IS SOME SURFACE WIND CONVERGENCE ON THE WARM FRONT WITH SOUTHEAST WINDS AHEAD OF IT AND SOUTH WINDS BEHIND THIS. I DO NOT BELIEVE LIKE THE MODELS FORECAST THAT IT WILL BECOME ALL SOUTHERLY WINDS WITH AFTERNOON HEATING SINCE THERE WILL BE CLOUD AHEAD OF THE WARM FRONT (ALREADY THERE). THUS I BELIEVE THE AREA OF SHOWERS COMING ON SHORE MAY MIX OUT SOUTH OF MKG BY LATE MORNING BUT THE SCT SHOWERS DEVELOPING NORTH OF MKG SHOULD MAINTAIN THEMSELVES. DUE TO THE NARROW CAPE I DO NOT SEE A HAIL THREAT EVEN THOUGH THE WET BULB ZERO IS BELOW 10000 FT. DTX AND APX SOUNDING SHOW ENOUGH DRY AIR TO LIMIT WHAT SHOWERS THERE WILL BE...STILL SEEMS REASONABLE TO GO WITH 30 POP WITH WARM FRONT. SKIES WILL CLEAR NICELY BEHIND THE AREA OF SCT SHOWERS... SO HIGH TEMPERATURES SHOULD GET TO BETWEEN 75 AND 80F ANYWAY. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WDM mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE RALEIGH NC 932 AM EDT MON APR 18 2005 .SHORT TERM (REST OF TODAY)... AREA OF MID LEVEL CLOUDS ACROSS THE NORTHERN PIEDMONT/COASTAL PLAIN IS ASSOCIATED WITH PVA AHEAD OF A CONCENTRIC VORT MAX...WHICH WILL MOVE SOUTH ACROSS THE AREA THROUGH THE MORNING. EXTRAPOLATION AND THE RUC TAKE THE PVA OUT OF OUR AREA BY EARLY AFTERNOON. CLOUDS APPEAR TO BE THIN AND FAST-MOVING...SO THEY SHOULD HAVE LITTLE IMPACT ON THE CURRENT MOSTLY SUNNY FORECAST AND HIGH TEMPERATURES AROUND 80/LOWER 80S. NO SIGNIFICANT CHANGES WITH THE UPDATE...WILL ONLY REMOVE AFTERNOON WORDING. && .FIRE WEATHER... 12Z GSO SOUNDING SHOWS A DRY ADIABATIC LAYER UP TO 700 MB...WHICH GIVES A MIXING HEIGHT AROUND 9 KFT. WILL UPDATE TO RAISE MIXING HEIGHTS. SOME MIXING OF DRIER AIR MAY LOWER RH VALUES QUICKLY THIS MORNING...BUT EXPECT RH WILL STAY ABOVE 30% IN MOST SPOTS. SURFACE WINDS WILL BE AROUND 5 MPH AND PREDOMINANTLY FROM THE SOUTHWEST. && .PREVIOUS DISCUSSION... (ISSUED 225 AM EDT MON APR 18 2005) SHORT TERM (TODAY THROUGH WEDNESDAY NIGHT)... LOOKING AT MODEL SOUNDINGS AND THICKNESSES IS SEEMS LIKELY THAT AFTERNOON MIXING HEIGHTS WILL BE UNDERDONE DURING THE PERIOD. WILL STAY ON THE WARM SIDE OF GUIDANCE DURING THE AFTERNOONS. GFS PERSISTENT IN THROWING SPITS OF RAIN OVER THE AREA THROUGH THE PERIOD. CANADIAN JUST AS PERSISTENT IN KEEPING IT DRY. GIVEN THE EAST COAST RIDGE AND WEST TO NORTHWEST FLOW WILL CONTINUE TO SIDE WITH THE DRIER FORECAST. LONG TERM (THURSDAY THROUGH SUNDAY)... WEAK TROUGH STILL FORECAST TO SLIP SOUTH INTO OUR AREA THURSDAY AND WILL AGAIN INTRODUCE POPS TO THIS PERIOD. A COOL DOWN AND A BREAK FROM POPS THEN UPPER LEVEL TROUGH TO DRIVE ANOTHER CHANCE FOR RAIN INTO THE AREA FRIDAY NIGHT AND SATURDAY. DRYING AND COOLING BEHIND THIS TROUGH SUNDAY. AVIATION... EXPECT A PERIOD OF SCATTERED TO BROKEN ALTOCUMULUS FROM AROUND SUNRISE THROUGH THE MORNING... AS A STRONG BUT MOISTURE STARVED SHORTWAVE TROUGH DROPS DOWN IN NORTHWEST FLOW ALOFT. VFR VISIBILITIES AND LIGHT MAINLY SOUTHWEST WINDS SHIFTING TO WEST TO NORTHWEST AT ALL TAF SITES. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM/FIRE WEATHER...DGS nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 910 PM CDT MON APR 18 2005 .EVENING UPDATE... FCST CONCERNS CENTERS ON CHANCE OF CONVECTION REMAINDER OF TONIGHT. SFC MAP SHOWS COOL FRONT LOCATED FROM JUST WEST OF BAUDETTE TO JUST SOUTH OF GRAND FORKS THEN TO JUST NORTH OF JAMESTOWN. AREA OF LOCALLY SVR TSRA FORMED RIGHT ALONG WIND SHIFT LINE AT 22Z AS AREA FROM BAUDETTE TO GRAND FORKS TO JAMESTOWN HEATED OUT TO CONVECTIVE TEMPS. 88 AT GFK BEING THE WARMEST AND ONE DEGREE SHY OF RECORD. NARROW BAND OF MULTICELLULAR STORMS FORMED WITH LOCAL .75 TO .88 HAILERS ALONG WIND SHIFT. LAPS/RUC SHOWS CIN NOW INCREASING AS ATMOSPHERE COOLS AND THUS TSRA HAS BEEN WEAKENING. HOWEVER...STILL SOUTHERLY TO SOUTHWESTERLY 850 MB WINDS OVERUNNING COOLER BOUNDARY LAYER AIR IS CONTINUE TO AID IN ISOLD SHOWER/STORM DEVELOPMENT TIL JUST PAST 06Z...AND POSSIBLY BEYOND WITH BEST CONVERGENCE THEN SHIFTING TO NCNTRL MN PER LATEST NAM/ETA. ALL IN ALL...THINK SEVERE THREAT IS OVER...BUT ISOLD SHOWER/STORM ACTIVITY TO CONTINUE OVER NE ND INTO NRN MN. WIND SHIFT TO REACH FARGO-BEMIDJI JUST PAST MIDNIGHT AND THEN CONTINUES TO DROP SOUTH...BUT LACK OF HEATING AND STRONG CAP WILL PREVENT CONVECTION. WILL LOOK OVER ZFP/GRIDDS BUT MAY CONSIDER DROPPING PCPN CHANCES IN SE ND/WCNTRL MN. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ RIDDLE nd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 925 PM CDT MON APR 18 2005 .UPDATE... LINEAR MCS SHOULD HAVE A HARD TIME MAKING IT MUCH FURTHER EAST THAN KSPS-KRPH LINE AND WEAKENING AS IT DOES SO...AS BOUNDARY LAYER CONTS STABILIZING AND ACTIVITY MOVES IN INTO WEAKER H5-H7 FLOW AND WEAKENING LAPSE RATES IN THAT SAME LAYER. ONGOING 30-40 LLJ OVER W-CENTRAL TX PER PROFILERS AND LITTLE CAP ON 00Z/FWD SOUNDING STILL INDICATE SOME ISOLATED SHOWERS POSSIBLE AFTER MIDNIGHT WITH DECAYING MCS W/NW OF KDFW. ADJUSTED POPS THOSE AREAS TO INDICATE THESE TRENDS..WITH SPRINKLES ELSEWHERE THROUGH MID MORNING TUES WITH AMPLE LOW LVL MSTR IN PLACE. OTHERWISE...MADE MINOR ADJUSTMENTS ON WINDS/CLOUDS AND DEW PTS. && .PREV DISCUSSION... /ISSUED 340 PM CDT MON APR 18 2005/ DISCUSSION... ISOLATED LIGHT SHOWERS ARE CURRENTLY BEING OBSERVED IN KFWS/KGRK 88D REFLECTIVITY DATA...BUT ARE PRIMARILY OCCURRING TO THE EAST OF A LINE FROM KBMQ...TO KCPT/KGYI. SHORT TERM RUC/ETA GUIDANCE INDICATES THAT THE MOST SIGNIFICANT RESIDUAL VERTICAL MOTION ASSOCIATED WITH THE DEPARTING UPPER WAVE WILL OCCUR ACROSS THE EASTERN PORTION OF THE FORECAST AREA OVERNIGHT...AND WILL CONFINE SLIGHT CHANCE POPS TO THIS REGION. PERSISTENCE WILL BE USED FOR BOTH MAXIMUM AND MINIMUM TEMPERATURES IN THE SHORT TERM...WITH AVAILABLE MOS GUIDANCE VERY SIMILAR. FURTHER INTO THE SHORT TERM PORTION OF THE FORECAST...SEVERAL COMPETING FACTORS EXIST...WHICH CONTINUE TO MAKE FOR A VERY DIFFICULT PRECIPITATION FORECAST. THE LATEST RUNS OF THE ETA/GFS ARE IN GOOD AGREEMENT ON A SHARPENING OF THE DRYLINE ACROSS WEST TEXAS TOMORROW AFTERNOON...AS A LARGE UPPER LOW CONTINUES TO DRIFT SLOWLY SOUTHWARD ACROSS THE GREAT BASIN. HOWEVER...DOWNSTREAM HEIGHT RISES WILL LIKELY LIMIT THE COVERAGE OF CONVECTION THIS FAR TO THE EAST ON TUESDAY AFTERNOON. THUS...ONLY SLIGHT CHANCE POPS WILL BE MAINTAINED FOR THE FAR WESTERN COUNTIES...WHICH HAVE THE HIGHEST PROBABILITY OF BEING AFFECTED BY DRYLINE ACTIVITY. CONDITIONS APPEAR TO BECOME SLIGHTLY MORE FAVORABLE FOR CONVECTION BY LATE WEDNESDAY AND EARLY THURSDAY...AS THE UPPER TROUGH OVER THE PACIFIC NORTHWEST RETROGRADES AND ALLOWS A MORE ZONAL FLOW PATTERN TO BECOME ESTABLISHED OVER THE SOUTHERN PLAINS. THE RESULT OF THIS...AND AN INCREASINGLY UNSTABLE AIRMASS...SHOULD ALLOW FOR A GREATER COVERAGE OF THUNDERSTORMS ACROSS THE NORTHERN/WESTERN PORTION OF THE FORCAST AREA FROM WEDNESDAY NIGHT THROUGH THURSDAY MORNING. AT THIS TIME... IT APPEARS THAT STRONG INSTABILITY WILL FAVOR THE POTENTIAL FOR LARGE HAIL WITH STORMS THAT AFFECT THE AREA...BUT WEAK DEEP LATER SHEAR WILL LIKELY PREVENT A WIDESPREAD SEVERE WEATHER EVENT. BY THURSDAY...MEDIUM RANGE GFS/ECMFW GUIDANCE CONTINUES TO ADVERTISE THE DEVELOPMENT OF A STRONG SUBTROPICAL RIDGE ACROSS CENTRAL MEXICO AND ADJACENT PORTIONS OF THE PACIFIC OCEAN AND GULF OF MEXICO. THIS FEATURE IS PROGGED TO BUILD OVER THE SOUTHERN PLAINS ON THURSDAY. THUS...WE WILL REMOVE POPS FROM THE FORECAST FOR THE PERIOD FROM THURSDAY MORNING THROUGH LATE FRIDAY...AS STRONG ANTICYCLONIC CURVATURE IN THE MID/UPPER LEVELS WILL PROVIDE A VERY UNFAVORABLE ENVIRONMENT FOR THE DEVELOPMENT OF DEEP/MOIST CONVECTION. HOWEVER... WITH THE APPROACH OF A SIGNIFICANT LATE SEASON COLD FRONT ON FRIDAY NIGHT...WE WILL MAINTAIN SLIGHT CHANCES FOR SHOWERS/THUNDERSTORMS. BENEATH WEAK FLOW ALOFT...THIS BOUNDARY WILL LIKELY LINGER AROUND THE AREA THROUGH EARLY NEXT WEEK BEFORE LIFTING NORTHWARD...AND WE WILL CARRY SLIGHT CHANCES THROUGH THE END OF THE FORECAST PERIOD. && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ /05 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SAN ANGELO TX 759 PM CDT MON APR 18 2005 .UPDATE... NO UPDATES. ANOTHER SHORTWAVE PUSHING THROUGH THE BIG BEND THIS EVENING...SO MAY SEE SOME ISOLATED SHOWERS/THUNDERSTORMS. ATMOSPHERE HOWEVER PRETTY MUCH CAPPED OFF HOWEVER AS INDICATED BY DRT AND MAF UPPER SOUNDINGS. 04 && .PREV DISCUSSION... (ISSUED 330 PM CDT MON APR 18 2005) SHORT TERM... THE LATEST FORECAST SCENARIO IS RATHER TROUBLESOME EVEN IN THE SHORT TERM. LATEST ANALYSES AND SATELLITE IMAGERY SHOW AN UPPER TROUGH IN THE NORTHERN BRANCH OF THE JET DIGGING INTO NORTHER CALIFORNIA. THE SOUTHERN BRANCH REMAINS OVER NORTHERN MEXICO AND INTO WEST AND CENTRAL TEXAS. STRONG LLJ REMAINS OVER THE PLAINS AND AT THE SURFACE...THE DRYLINE REMAINS MAINLY IN EAST NM. DRYLINE IS TRYING TO MIX EAST WITH LITTLE SUCCESS DUE TO EARLIER CLOUD COVER WHICH HAS LIFTED SOME. THIS HAS ALLOW FOR SOME DAYTIME HEATING AND HAS ALLOWED FOR SOME DESTABILIZATION OVER W TX. WATER VAPOR IMAGERY SHOWS A WEAK DISTURBANCE IN THE SOUTHERN JET NOW ENTERING THE BIG BEND AREA. THIS IS HELPING TO INITIATE STORMS NEAR FORT STOCKTON. 12Z MAF SOUNDING DID SHOW A DECENT CAP WITH 18C AT 825MB. EVEN WITH THE DISTURBANCE...CAP SHOULD ALLOW FOR MAINLY ISOLATED STORMS. CAPE IN THE REGION REMAINS IN THE 1000 TO 2000 J/KG RANGE WITH 0-6KM SHEAR NEAR 30 TO 40KTS. STORM MODE SHOULD LEAN TOWARDS MULTICELL WITH A FEW BECOMING SUPERCELLS WHERE SHEAR IS MAXED OUT. PER LATEST RUC ANALYSES...BEST SHEAR LOOKS TO BE OVER THE BIG BEND AREA WITH THE DISTURBANCE...BUT CAPE IS CLOSER TO 1000 J/KG. ON THE OTHER HAND...THE RUC SHOWS CAPE NEAR 2000 J/KG OVER THE BIG COUNTRY AND INTO THE TX PANHANDLE...BUT SHEAR IS LIMITED CLOSER TO 30KTS. FOR THE NEXT 24 HRS...MAY EXPECTED A FEW ISOLATED STORMS SO ONLY HAVE 20 TO 30 POPS MAINLY DUE TO CAP STRENGTH AND TIMING OF ANY DISTURBANCES WHICH THE MODELS ARE NOT DEPICTING WELL AT ALL. SAME TYPE OF SCENARIO IS SET UP FOR TOMORROW AS WELL. ONLY DIFFERENCES ARE THAT THE DRYLINE MAY SHARPEN UP MORE AND MIX FARTHER EAST. MOISTURE SHOULD REMAIN IN PLACE OVER MUCH OF WEST CENTRAL TEXAS. SHEAR WILL BE LIMITED AGAIN BUT SOUTHERN JET SHOULD STILL BE SOMEWHAT ACTIVE WITH A COUPLE OF DISTURBANCES THAT THE MODELS HAVE A HARD TIME RESOLVING. KEEP MAINLY 20 TO 30 POPS FOR THE AFTERNOON...30S IN THE EASTERN AREAS WHERE MOISTURE...INSTABILITY AND LIFT MAY BE MAXIMIZED. STORMS STILLS SHOULD LEAN TOWARDS MULTICELLS WITH A FEW STORMS POSSIBLY ROTATING IF LOCATED IN BETTER SHEAR. LONG TERM... WEDNESDAY LOOKS TO BE SIMILAR TO THE PREVIOUS DAYS AS WELL EXCEPT NOT AS MUCH FORCING WITH THE GREAT BASIN UPPER TROUGH LIFTING NORTHWARD INTO THE NORTHERN ROCKIES. REGARDLESS...UPPER FLOW SHOULD STILL BE WESTERLY WITH A FEW DISTURBANCES AND AN ACTIVE DRYLINE. THIS IS ENOUGH TO KEEP 20 POPS GOING UNTIL UPPER LEVEL RIDGING BEGINS WED NIGHT INTO THURSDAY. UPPER RIDGING SHOULD CONTINUE THROUGH THE END OF THE WEEK WHICH MAY ALLOW FOR DAYTIME TEMPS TO CLIMB INTO THE MID 80S. THE REAL QUESTION MARK BEGINS SATURDAY AS A BACK DOOR FRONT WORKS ITS WAY TOWARDS CENTRAL TX. GFS SOLUTION IS IFFY AT BEST AS ON WEDNESDAY IT INITIATES A CONVECTIVELY FEEDBACK VORTICITY MAX WHICH ROTATES AROUND THE BUILDING RIDGE AND AROUND THE EDGE OF A DEEP UPPER TROUGH OVER THE NORTHEAST U.S. THIS FEATURE TRACKS ALONG THE FRONT AS WELL AND DEVELOPS ANOTHER LOW ON FRIDAY AND MOVES UP THE EAST COAST ON SATURDAY. SEEMS THIS FEATURE MAY HELP PUSH THE FRONT INTO TX EARLIER THAT PREVIOUSLY THOUGHT AND COMPARED TO 06Z MODEL RUNS. CURRENT THINKING IS TO SLOWLY INTRODUCE THIS FRONT AND MAINLY HAVE WINDS TURN MORE EASTERLY AND COOL TEMPS SOME COMPARED TO GUIDANCE OVER THE WEEKEND. FEEL THAT ANOTHER SHORTWAVE EMBEDDED IN THE UPPER FLOW OF THE NORTHEAST US TROUGH WILL HELP PUSH THIS FRONT THROUGH...BUT DIFFICULT TO TELL HOW STRONG THE FRONT WILL BE AND EXACTLY WHAT THE TIMING WILL BE. LATEST ECMWF SHOWS A SIMILAR DEVELOPMENT SO THE MODELS MIGHT BE COMING IN LINE FOR THE EXTENDED PART OF THE FORECAST. THE HOPE IS TO SEE MORE MODEL CONSISTENCY IN THE EXTENDED RANGE BEFORE REALLY BUYING INTO THEM. && .SJT WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ 04/04 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 340 PM CDT MON APR 18 2005 .DISCUSSION... ISOLATED LIGHT SHOWERS ARE CURRENTLY BEING OBSERVED IN KFWS/KGRK 88D REFLECTIVITY DATA...BUT ARE PRIMARILY OCCURRING TO THE EAST OF A LINE FROM KBMQ...TO KCPT/KGYI. SHORT TERM RUC/ETA GUIDANCE INDICATES THAT THE MOST SIGNIFICANT RESIDUAL VERTICAL MOTION ASSOCIATED WITH THE DEPARTING UPPER WAVE WILL OCCUR ACROSS THE EASTERN PORTION OF THE FORECAST AREA OVERNIGHT...AND WILL CONFINE SLIGHT CHANCE POPS TO THIS REGION. PERSISTENCE WILL BE USED FOR BOTH MAXIMUM AND MINIMUM TEMPERATURES IN THE SHORT TERM...WITH AVAILABLE MOS GUIDANCE VERY SIMILAR. FURTHER INTO THE SHORT TERM PORTION OF THE FORECAST...SEVERAL COMPETING FACTORS EXIST...WHICH CONTINUE TO MAKE FOR A VERY DIFFICULT PRECIPITATION FORECAST. THE LATEST RUNS OF THE ETA/GFS ARE IN GOOD AGREEMENT ON A SHARPENING OF THE DRYLINE ACROSS WEST TEXAS TOMORROW AFTERNOON...AS A LARGE UPPER LOW CONTINUES TO DRIFT SLOWLY SOUTHWARD ACROSS THE GREAT BASIN. HOWEVER...DOWNSTREAM HEIGHT RISES WILL LIKELY LIMIT THE COVERAGE OF CONVECTION THIS FAR TO THE EAST ON TUESDAY AFTERNOON. THUS...ONLY SLIGHT CHANCE POPS WILL BE MAINTAINED FOR THE FAR WESTERN COUNTIES...WHICH HAVE THE HIGHEST PROBABILITY OF BEING AFFECTED BY DRYLINE ACTIVITY. CONDITIONS APPEAR TO BECOME SLIGHTLY MORE FAVORABLE FOR CONVECTION BY LATE WEDNESDAY AND EARLY THURSDAY...AS THE UPPER TROUGH OVER THE PACIFIC NORTHWEST RETROGRADES AND ALLOWS A MORE ZONAL FLOW PATTERN TO BECOME ESTABLISHED OVER THE SOUTHERN PLAINS. THE RESULT OF THIS...AND AN INCREASINGLY UNSTABLE AIRMASS...SHOULD ALLOW FOR A GREATER COVERAGE OF THUNDERSTORMS ACROSS THE NORTHERN/WESTERN PORTION OF THE FORCAST AREA FROM WEDNESDAY NIGHT THROUGH THURSDAY MORNING. AT THIS TIME... IT APPEARS THAT STRONG INSTABILITY WILL FAVOR THE POTENTIAL FOR LARGE HAIL WITH STORMS THAT AFFECT THE AREA...BUT WEAK DEEP LATER SHEAR WILL LIKELY PREVENT A WIDESPREAD SEVERE WEATHER EVENT. BY THURSDAY...MEDIUM RANGE GFS/ECMFW GUIDANCE CONTINUES TO ADVERTISE THE DEVELOPMENT OF A STRONG SUBTROPICAL RIDGE ACROSS CENTRAL MEXICO AND ADJACENT PORTIONS OF THE PACIFIC OCEAN AND GULF OF MEXICO. THIS FEATURE IS PROGGED TO BUILD OVER THE SOUTHERN PLAINS ON THURSDAY. THUS...WE WILL REMOVE POPS FROM THE FORECAST FOR THE PERIOD FROM THURSDAY MORNING THROUGH LATE FRIDAY...AS STRONG ANTICYCLONIC CURVATURE IN THE MID/UPPER LEVELS WILL PROVIDE A VERY UNFAVORABLE ENVIRONMENT FOR THE DEVELOPMENT OF DEEP/MOIST CONVECTION. HOWEVER... WITH THE APPROACH OF A SIGNIFICANT LATE SEASON COLD FRONT ON FRIDAY NIGHT...WE WILL MAINTAIN SLIGHT CHANCES FOR SHOWERS/THUNDERSTORMS. BENEATH WEAK FLOW ALOFT...THIS BOUNDARY WILL LIKELY LINGER AROUND THE AREA THROUGH EARLY NEXT WEEK BEFORE LIFTING NORTHWARD...AND WE WILL CARRY SLIGHT CHANCES THROUGH THE END OF THE FORECAST PERIOD. && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 65 76 66 80 / 0 10 0 10 WACO, TX 63 79 64 82 / 0 10 0 10 PARIS, TX 60 76 61 79 / 20 10 0 10 DENTON, TX 63 76 64 80 / 0 10 0 10 MCKINNEY, TX 63 76 64 79 / 0 10 0 10 DALLAS, TX 65 76 66 80 / 0 10 0 10 TERRELL, TX 63 76 64 79 / 20 10 0 10 CORSICANA, TX 63 76 64 79 / 20 10 0 10 TEMPLE, TX 63 79 64 82 / 0 10 0 10 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ 65/DD tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 330 PM CDT MON APR 18 2005 .SHORT TERM... THE LATEST FORECAST SCENARIO IS RATHER TROUBLESOME EVEN IN THE SHORT TERM. LATEST ANALYSES AND SATELLITE IMAGERY SHOW AN UPPER TROUGH IN THE NORTHERN BRANCH OF THE JET DIGGING INTO NORTHER CALIFORNIA. THE SOUTHERN BRANCH REMAINS OVER NORTHERN MEXICO AND INTO WEST AND CENTRAL TEXAS. STRONG LLJ REMAINS OVER THE PLAINS AND AT THE SURFACE...THE DRYLINE REMAINS MAINLY IN EAST NM. DRYLINE IS TRYING TO MIX EAST WITH LITTLE SUCCESS DUE TO EARLIER CLOUD COVER WHICH HAS LIFTED SOME. THIS HAS ALLOW FOR SOME DAYTIME HEATING AND HAS ALLOWED FOR SOME DESTABILIZATION OVER W TX. WATER VAPOR IMAGERY SHOWS A WEAK DISTURBANCE IN THE SOUTHERN JET NOW ENTERING THE BIG BEND AREA. THIS IS HELPING TO INITIATE STORMS NEAR FORT STOCKTON. 12Z MAF SOUNDING DID SHOW A DECENT CAP WITH 18C AT 825MB. EVEN WITH THE DISTURBANCE...CAP SHOULD ALLOW FOR MAINLY ISOLATED STORMS. CAPE IN THE REGION REMAINS IN THE 1000 TO 2000 J/KG RANGE WITH 0-6KM SHEAR NEAR 30 TO 40KTS. STORM MODE SHOULD LEAN TOWARDS MULTICELL WITH A FEW BECOMING SUPERCELLS WHERE SHEAR IS MAXED OUT. PER LATEST RUC ANALYSES...BEST SHEAR LOOKS TO BE OVER THE BIG BEND AREA WITH THE DISTURBANCE...BUT CAPE IS CLOSER TO 1000 J/KG. ON THE OTHER HAND...THE RUC SHOWS CAPE NEAR 2000 J/KG OVER THE BIG COUNTRY AND INTO THE TX PANHANDLE...BUT SHEAR IS LIMITED CLOSER TO 30KTS. FOR THE NEXT 24 HRS...MAY EXPECTED A FEW ISOLATED STORMS SO ONLY HAVE 20 TO 30 POPS MAINLY DUE TO CAP STRENGTH AND TIMING OF ANY DISTURBANCES WHICH THE MODELS ARE NOT DEPICTING WELL AT ALL. SAME TYPE OF SCENARIO IS SET UP FOR TOMORROW AS WELL. ONLY DIFFERENCES ARE THAT THE DRYLINE MAY SHARPEN UP MORE AND MIX FARTHER EAST. MOISTURE SHOULD REMAIN IN PLACE OVER MUCH OF WEST CENTRAL TEXAS. SHEAR WILL BE LIMITED AGAIN BUT SOUTHERN JET SHOULD STILL BE SOMEWHAT ACTIVE WITH A COUPLE OF DISTURBANCES THAT THE MODELS HAVE A HARD TIME RESOLVING. KEEP MAINLY 20 TO 30 POPS FOR THE AFTERNOON...30S IN THE EASTERN AREAS WHERE MOISTURE...INSTABILITY AND LIFT MAY BE MAXIMIZED. STORMS STILLS SHOULD LEAN TOWARDS MULTICELLS WITH A FEW STORMS POSSIBLY ROTATING IF LOCATED IN BETTER SHEAR. .LONG TERM... WEDNESDAY LOOKS TO BE SIMILAR TO THE PREVIOUS DAYS AS WELL EXCEPT NOT AS MUCH FORCING WITH THE GREAT BASIN UPPER TROUGH LIFTING NORTHWARD INTO THE NORTHERN ROCKIES. REGARDLESS...UPPER FLOW SHOULD STILL BE WESTERLY WITH A FEW DISTURBANCES AND AN ACTIVE DRYLINE. THIS IS ENOUGH TO KEEP 20 POPS GOING UNTIL UPPER LEVEL RIDGING BEGINS WED NIGHT INTO THURSDAY. UPPER RIDGING SHOULD CONTINUE THROUGH THE END OF THE WEEK WHICH MAY ALLOW FOR DAYTIME TEMPS TO CLIMB INTO THE MID 80S. THE REAL QUESTION MARK BEGINS SATURDAY AS A BACK DOOR FRONT WORKS ITS WAY TOWARDS CENTRAL TX. GFS SOLUTION IS IFFY AT BEST AS ON WEDNESDAY IT INITIATES A CONVECTIVELY FEEDBACK VORTICITY MAX WHICH ROTATES AROUND THE BUILDING RIDGE AND AROUND THE EDGE OF A DEEP UPPER TROUGH OVER THE NORTHEAST U.S. THIS FEATURE TRACKS ALONG THE FRONT AS WELL AND DEVELOPS ANOTHER LOW ON FRIDAY AND MOVES UP THE EAST COAST ON SATURDAY. SEEMS THIS FEATURE MAY HELP PUSH THE FRONT INTO TX EARLIER THAT PREVIOUSLY THOUGHT AND COMPARED TO 06Z MODEL RUNS. CURRENT THINKING IS TO SLOWLY INTRODUCE THIS FRONT AND MAINLY HAVE WINDS TURN MORE EASTERLY AND COOL TEMPS SOME COMPARED TO GUIDANCE OVER THE WEEKEND. FEEL THAT ANOTHER SHORTWAVE EMBEDDED IN THE UPPER FLOW OF THE NORTHEAST US TROUGH WILL HELP PUSH THIS FRONT THROUGH...BUT DIFFICULT TO TELL HOW STRONG THE FRONT WILL BE AND EXACTLY WHAT THE TIMING WILL BE. LATEST ECMWF SHOWS A SIMILAR DEVELOPMENT SO THE MODELS MIGHT BE COMING IN LINE FOR THE EXTENDED PART OF THE FORECAST. THE HOPE IS TO SEE MORE MODEL CONSISTENCY IN THE EXTENDED RANGE BEFORE REALLY BUYING INTO THEM. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 83 64 83 / 20 30 20 20 SAN ANGELO 63 83 63 83 / 30 30 20 20 JUNCTION 62 80 63 80 / 30 30 20 20 && .SJT WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ 07/10 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 315 AM EDT TUE APR 19 2005 .SHORT TERM...SURFACE ANALYSIS INDICATES THAT HIGH PRESSURE RIDGE AXIS HAS SETTLED OVER NORTH FLORIDA AT THIS HOUR. THIS HAS PROVIDED FOR VERY LIGHT WIND FLOW ACROSS THE REGION AND KEPT ONSHORE FLOW LIMITED TO THE EXTREME SOUTHERN SECTIONS. SYNOPTIC SETUP CONTINUED TO FAVOR FOG FORMATION...BUT DEEP LAYER DRY AIR JUST ABOVE THE SURFACE WILL LIMIT REDUCTIONS TO 4 TO 5 MILES IN MOST CASES. OTHERWISE...STARTING TO SEE SOME CIRRUS ENCROACH ON THE WESTERN ZONES AND EXPECT THIS TREND TO CONTINUE THROUGH SUNRISE. CONTINUED MODERATION IN STORE FOR AFTERNOON HIGH TEMPERATURES... ESPECIALLY FOR INLAND PORTIONS OF THE COASTAL COUNTIES WHERE SEA BREEZE PENETRATION WILL BE DELAYED FROM PREVIOUS DAYS. THIS WILL ALLOW TEMPERATURES TO CLIMB TO AROUND 80 FOR A GOOD PORTION OF THE CWA. AS FAR AS CLOUDS ARE CONCERNED...MAY SEE A FEW CU DEVELOP IN ONSHORE FLOW FOR SOUTHERNMOST COASTAL COUNTIES...BUT CONVECTIVE CU WILL BE NON-EXISTENT DUE TO CONTINUED VERY DRY BOUNDARY LAYER. WE WILL HOWEVER...CONTINUE TO SEE AN INCREASE IN HIGH LEVEL CLOUDINESS THROUGHOUT THE DAY AND WILL WORD WESTERN ZONES WITH INCREASING HIGH CLOUDINESS. FOR THE NEXT FEW NIGHTS...WE WILL BEGIN TO SEE A FEW DEGREES OF MODERATION IN DEWPOINTS AS WELL AS BOUNDARY LAYER MOISTURE ALLOWING FOR INCREASED PROSPECTS FOR PATCHY FOG. DURING THE DAY...AFTERNOON CU WILL BE ON THE INCREASE TO THE SOUTH WHERE ETA SHOWS SOME SEABREEZE CONVERGENCE LATE IN THE DAY ALONG WITH A NICE SHORT WAVE DIVING THROUGH THE AREA. MOISTURE STILL SEEMS TO BE LACKING HOWEVER FOR ANY DEVELOPING POPS AND WILL LEAVE GRIDS DRY IN THE SHORT TERM. CHANGES TO THE PATTERN BEGIN TO TAKE SHAPE LATE WEDNESDAY INTO THURSDAY AS A MORE SIGNIFICANT TROUGH BEGINS TO FORM OVER THE EASTERN THIRD OF THE U.S. THIS TROUGH WILL ALLOW THE TAIL END OF A WEAK FRONT TO SAG INTO THE NORTHERN ZONES LATE THURSDAY WITH GOOD AGREEMENT AMONG THE MODELS. FORCING WILL DEFINITELY BE LACKING WITH THIS SYSTEM...BUT INCREASED MOISTURE IN THE MID LEVELS...COMBINED WITH TEMPERATURES IN THE LOWER 80S WARRANTS SLIGHT CHANCE POPS FOR THE NORTHERN ZONES AT THIS TIME. .LONG TERM...CHANGES IN THE PATTERN CONTINUE INTO THE WEEKEND AS EAST COAST TROUGH BECOMES MORE WELL DEFINED. THIS WILL LEAD TO INCREASED RAIN CHANCES FOR AT LEAST THE FIRST HALF OF THE WEEKEND. CURRENT GRIDS REFLECT THIS WELL AND NO CHANGES ARE PLANNED. && .MARINE...LIGHT WINDS CONTINUE OVER THE MARINE AREA DUE TO RIDGE AXIS OVER NRN FL. SEAS HAVE COME DOWN TO 3-4 FT MOST OF THE AREA EXCEPT FOR THE OUTER WATERS AND ZONE AMZ474 WHERE SEAS ARE ESTIMATED TO BE AROUND 4-6 FT. AGAIN...WNA WAVE GUIDANCE IS TOO HIGH OVER THE MARINE ZONES AND HAVE LOWERED GUIDANCE BY 2-3 FT. WILL LIKELY HOLD ONTO SCEC FOR SEAS IN ZONE AMZ474 THIS MORNING. HIGH PRES RIDGE AXIS WILL CONTINUE TO MOVE SWD THROUGH THURSDAY RESULTING IN SLIGHT INCREASES IN SLY FLOW...PARTICULARLY OFFSHORE WATERS AND ON THU NIGHT. WIND INCREASES FROM W TO NW BY FRI AS SFC LOW DIPS SWD INTO SE CONUS AND DRAGS A COLD FRONT INTO THE REGION BY FIRST PART OF THE WEEKEND. && .FIRE WEATHER...A TOUGH CALL FOR SE GA AS MIN RH MAY DROP TO NEAR 22 TO 25 PERCENT THIS AFTN. PREFERRED THE DRIER MAV GUIDANCE AND EVEN LOWERED ITS DEWPOINTS A FEW DEGREES. FOR NOW...WILL LET DAY-SHIFT DECIDE ON WHETHER TO GO WITH SHORT FUSE RED FLAG WARNING THERE. HOWEVER...WILL MONITOR MODEL GUIDANCE FROM RUC NEXT FEW HRS FOR POSSIBLE RED FLAG INTERIOR SE GA AS IT OUTPERFORMED OTHER MODELS FROM YESTERDAY. RED FLAG WARNING FOR INTERIOR NE FL LOOKS GOOD WITH MIN RHS NEAR MID 20S. FIRE WX WATCH APPEARS TO BE NEEDED FOR WED AFTN FOR SUWANNEE VALLEY AREA WITH MIN RHS NEAR 30%. && .PRELIMINARY POINT TEMPS/POPS... AMG 81 52 82 56 / 0 0 0 0 SSI 74 57 76 57 / 0 0 0 0 JAX 79 54 81 55 / 0 0 0 0 SGJ 73 56 76 57 / 0 0 0 0 GNV 80 51 83 54 / 0 0 10 10 OCF 81 52 84 55 / 0 0 10 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...RED FLAG WARNING IN EFFECT FROM 1 PM UNTIL 7 PM EDT TUESDAY FOR THE FOLLOWING ZONES...ALACHUA...BAKER...BRADFORD...CLAY... COLUMBIA...DUVAL...GILCHRIST...HAMILTON...MARION... NASSAU...PUTNAM...SUWANNEE...AND UNION. FIRE WEATHER WATCH FOR WED AFTN FOR THE FOLLOWING ZONES... HAMILTON...SUWANNEE...COLUMBIA...UNION...AND BAKER. GA...NONE. MARINE...NONE. && $$ PUBLIC...DEESE MARINE/FIRE WX...SHASHY fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 330 AM CDT TUE APR 19 2005 .DISCUSSION FOR MORNING GRIDS/ZONES... MAIN CONCERNS THROUGH THE FORECAST WILL BE PRECIP CHANCES BEGINNING THIS AFTERNOON ACROSS NORTHWEST PORTIONS OF CWA...THEN ACROSS REMAINDER OF THE AREA TONIGHT INTO WEDNESDAY. UPPER LEVEL CIRCULATION EVIDENT ON WATER VAPOR AND PROFILER DATA THIS MORNING CENTERED IN FAR NORTHWEST IOWA. THIS WAVE WILL CONTINUE TO LIFT EAST THROUGH MEAN UPPER RIDGE INTO WESTERN WISCONSIN TONIGHT. THIS WAVE WILL ENTER MID/UPPER LEVEL CONFLUENCE ZONE TONIGHT WITH ANOTHER WAVE KICKING THROUGH NORTHERN STREAM ACROSS SOUTHERN CANADA. NET EFFECT WILL BE TO DRAG LOW LEVEL BOUNDARY SOUTHEASTWARD WITH NAM/GFS PROGS IN REASONABLE AGREEMENT REGARDING TIMING OF COLD FRONT PASSAGE. DID REMOVE POPS ACROSS NORTHEAST ILLINOIS FOR THIS AFTERNOON. 00Z RAOB PLOTS SHOW SOME RELATIVELY DRIER AIR AT 850 HPA ACROSS LOWER MISSISSIPPI VALLEY WHICH RUC/NAM PROGS ADVECT INTO EASTERN ILLINOIS NORTHWEST INDIANA THIS AFTERNOON. MID LEVEL LAPSE RATES ALSO NOT ESPECIALLY STEEP WITH FORECAST SOUNDINGS STILL SHOWING MID LEVEL ISOTHERMAL LAYER...SO COMBINATION OF LACK OF LOW LEVEL MOISTURE AND MARGINAL LAPSE RATES SHOULD KEEP THINGS DRY ACROSS MOST OF CWA THIS AFTERNOON. DID KEEP SOME LOW CHANCE POPS FOR TSRA ACROSS FAR NORTHWEST THIS AFTERNOON WITH SOME BETTER LOW LEVEL MOISTURE IN THIS AREA AND WEAKER INHIBITION. ANOTHER WARM DAY IN STORE WITH TEMPS RISING INTO THE UPPER 70S TO LOWER 80S. FOR TONIGHT LOW LEVEL BOUNDARY SHOULD SAG TO WI/IL BORDER BY WEDNESDAY MORNING WITH INCREASING LOW LEVEL FRONTOGENESIS AND INCREASING LOW LEVEL MOISTURE POOLING NEAR THE BOUNDARY. WILL UP POPS TO LIKELY ACROSS FAR NORTHWEST AND CARRY LIKELY POPS FROM NORTH TO SOUTH ON WEDNESDAY WITH SOUTHWARD PROGRESSION OF THE FRONT. BRUNT OF CAA RELATIVELY SHALLOW SETTING UP DECENT FRONTAL INVERSION ON WEDNESDAY BUT STRENGTH OF LOW LEVEL CAA SHOULD PROMOTE DOWNWARD TEMP TREND ON WEDNESDAY WITH AREAS ALONG THE LAKE PROBABLY DIPPING BACK INTO UPPER 40S IN THE AFTERNOON. SOME DECENT SURFACE BASED INSTABILITY FOR AREAS WELL SOUTH OF INTERSTATE 80 ON WEDNESDAY. GIVEN TIMING OF FROPA...COULD SEE FEW STRONG STORMS ACROSS FAR SOUTHERN CWA WEDNESDAY AFTERNOON BUT BETTER THREAT DOES APPEAR TO BE JUST SOUTH OF THE AREA. GFS/NAM SOLUTIONS DIVERGE SOMEWHAT FOR FRIDAY WITH NAM BRINGING IN MORE SIGNIFICANT ISENTROPIC LIFT AS MORE AMPLIFIED UPPER WAVE ACROSS WESTERN CONUS ENTERS INTO MID MS VALLEY. GFS SUPPRESSES THIS LIFT FURTHER TO THE SOUTH WITH MORE PRONOUNCED SHORT WAVES RIDING THROUGH THE NORTHERN STREAM. MADE VERY FEW CHANGES TO THIS PERIOD AND WILL KEEP CHANCE OF RAIN SHOWERS GOING FROM LATE THURSDAY NIGHT INTO FRIDAY. MAIN CHANGE TO LONGER RANGE FRI-MON PERIOD WAS FOR COOLER CONDITIONS AS UPPER FLOW TRANSITIONS TO MORE AMPLITUDE WITH EASTERN CONUS TROUGH AND RIDGING OVER THE ROCKIES. THIS WILL RESULT IN TEMPS AT OR SLIGHTLY BELOW SEASONAL NORMS THROUGH MUCH OF THE WEEKEND. GFS/CANADIAN HAVE BEEN SOMEWHAT CONSISTENT WITH STRONGER NORTHERN STREAM WAVE DROPPING INTO UPPER MS VALLEY SUNDAY INTO MONDAY AND WILL MAINTAIN SHOWER CHANCES FOR THIS PERIOD ALSO. NDM && .AVIATION... MAIN FCST CONCERN IN SHORT TERM IS LAKE BREEZE BOUNDARY WHICH HAD DRIFTED INLAND JUST EAST OF KORD...AND RIGHT ON TOP OF KMDW AT 23Z. EXPECT KORD AND KMDW TO COME AROUND TO ESE...BUT AOB 10 KTS OR PERHAPS EVEN VRBL SHORTLY...THEN WITH LK BRZ LOSING PUSH WITH SUNSET LOOK FOR SFC WINDS TO AGAIN BECOME LGT SOUTHERLY OVRNGT. SFC DEWPOINTS STILL IN MID 40S AND LITTLE TIGHTER SFC PRESSURE GRADIENT THAN LAST NIGHT...SO NOT EXPECTING HZ/BR TO BE A REAL SIG ISSUE...THOUGH HAVE KEPT A 5SM HZ TEMPO FOR KRFD AND KDPA BEFORE/AROUND SUNRISE TUES. SFC PRES GRADIENT CONTINUES TO TIGHTEN A LITTLE MORE TUES AHEAD OF LOW PRESSURE LIFTING THRU CNTRL PLAINS IN RESPONSE TO MID LVL S/WV TROUGH. FCST SOUNDINGS SUGGEST DEEP MIXED BOUNDARY LAYER WITH GUSTS INTO THE 20-25 KT RANGE BY AFTN WITH GRADUAL INCRS IN HIGH CLDS FROM WNW DURG THE DAY. FCST SOUNDINGS INDICATE ATMOSPHERE REMAINS CAPPED WITH FAIRLY WARM TEMPS ALOFT PRODUCING VERY SKINNY WEAK CAPE PROFILE ABOVE CAP. WILL KEEP TAFS DRY THRU 00Z AT THIS POINT...WITH BEST CHANCES FOR ORGANIZED CONVECTION/PCPN EXPECTED PERHAPS JUST OF TO THE WEST/NORTHWEST OF FCST AREA DURG AFTN...CLOSER TO SFC LOW/FRONTAL BOUNDARY NWRN IL...IA INTO WI. RATZER && .LOT...WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LK MI...NONE. $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 335 AM EDT TUE APR 19 2005 .DISCUSSION... MAIN FORECAST CONCERNS ARE THUNDERSTORMS FOR TODAY AND THEN THE COOL DOWN TONIGHT/WED AND AGAIN ON FRI CURRENT WEATHER...07Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED RIDGING ACROSS THE EAST HALF OF THE COUNTRY AND FROM THE EASTERN PACIFIC INTO SW CANADA. AN UPPER LOW WAS DEVELOP OVER NEVADA/IDAHO WHILE A SHRTWV TROUGH STRETCHED FROM CENTRAL SASKATCHEWAN INTO NORTHERN ONTARIO. AN UPPER LOW/SHRTWV WAS ALSO LOCATED OVER THE SIOUX FALLS AREA AND THUNDERSTORMS HAVE BEEN OCCURRING AROUND THIS LOW. OTHER THUNDERSTORMS WERE OVER WESTERN ONTARIO INTO NORTHERN LAKE SUPERIOR AHEAD OF THE CENTRAL CANADA SHRTWV TROUGH. THESE STORMS WERE ALSO AIDED BY 800-700MB FRONTOGENESIS AND UPPER DIVERGENCE IN THE RIGHT ENTRANCE REGION OF A 80-90 JET OVER NORTHERN ONTARIO. UPPER MICHIGAN IS DRY AND CLEAR...AIDED BY STRONG SUBSIDENCE UNDER THE RIDGE AXIS. UNSEASONABLY WARM CONDITIONS TOO WITH READINGS AWAY FROM LAKE MICHIGAN IN THE 55 TO 65 DEGREE RANGE (NORMAL HIGH FOR THE OFFICE IS 50). 850MB TEMPS AT 00Z WERE ANYWHERE FROM +12C EAST TO +14C WEST...WHICH COMBINED WITH THE GREAT MIXING HELPED PROPEL YESTERDAYS TEMPERATURES TO NEAR 80 (SEE 00Z MPX SOUNDING WHICH SHOWS INVERTED-V WITH BASE AT 800). AT THE SURFACE...A COLD FRONT EXTENDED FROM JAMES BAY TO INTERNATIONAL FALLS. BEHIND THE FRONT... TEMPERATURES ARE IN THE 30S ASSOCIATED WITH HIGH PRESSURE IN SASKATCHEWAN. NE WINDS OF 10 TO 20 KT HAVE BEEN OBSERVED RIGHT BEHIND THE FRONT. TODAY...DISAGREEMENTS CONTINUE ON THE TRACK OF THE UPPER LOW OVER SIOUX FALLS...BUT THERE DOES SEEM TO BE CONVERGENCE ON A TRACK IN BETWEEN LA CROSSE AND MINNEAPOLIS BY 00Z. THE COLD FRONTAL TIMING APPEARS TO BE BETTER THOUGH WITH THE FRONT MOVING THROUGH THE KEWEENAW BY 18Z...WATERSMEET AND MQT BY 21Z AND INTO THE LAKE MICHIGAN COUNTIES BY 00Z. AHEAD OF THE FRONT...EXPECT CLOUDS TO BE ON THE INCREASE AHEAD OF THE UPPER LOW. NAM/GFS SHOW SOME SHOWERS AND THUNDERSTORMS DEVELOPING OUT OF THESE CLOUDS...WHICH APPEARS TO BE THE RESULT OF ISENTROPIC LIFT ACTING ON ELEVATED INSTABILITY (ELEVATED CAPES OF 300 J/KG). A COMBINATION OF UPPER DIVERGENCE FROM THE UPPER LEVEL JET MOVING SOUTH...800-700MB FRONTOGENESIS AND PVA FROM THE APPROACHING UPPER LOW WILL HELP TO INCREASE THE COVERAGE OF THE SHOWERS AND THUNDERSTORMS IN THE AFTERNOON. BEST COVERAGE EXPECTED IN THE WEST HALF OF THE U.P...CLOSER TO THE BETTER UPPER DIVERGENCE/FRONTOGENESIS. LOW 0-6KM VERTICAL SHEAR (ON THE ORDER OF 20 KNOTS) SHOULD PREVENT MUCH IN THE WAY OF STORM ORGANIZATION. HOWEVER...WITH FREEZING LEVELS AT 10000 FT ASL...COULD NOT RULE OUT SOME SMALL HAIL. HIGH TEMPERATURES TODAY WILL BE QUITE WARM AGAIN GIVEN HOW HIGH READINGS ARE AT THE MOMENT AND THAT SUNSHINE WILL OCCUR FOR SOME OF THE U.P. THIS MORNING. ALSO...MORE SUNSHINE SHOULD AFFECT THE SOUTH CENTRAL AND EASTERN AREAS THIS AFTERNOON AWAY FROM THE RAINS AHEAD OF THE COLD FRONT. WILL GO CLOSE TO ETA MOS GUIDANCE. TEMPERATURES SHOULD FALL TOO IN THE AFTERNOON NORTH OF M-28 AND WEST OF MARQUETTE AS THE FRONT MOVES THROUGH. TONIGHT...AS THE CENTRAL CANADA SHRTWV DIVES SOUTHEASTWARD...IT HELPS TO PUSH THE UPPER LOW TO THE ESE INTO CENTRAL/SOUTHERN LAKE MICHIGAN BY 12Z WED. EXPECT MUCH OF THE EVENING HOURS TO BE DOMINATED BY CONVECTION...HEADING TO THE SOUTHEAST FOLLOWING THE UPPER JET/800-700MB FRONTOGENESIS. CONVECTION SHOULD BE OUT OF THE WESTERN U.P. BY MIDNIGHT AND THEN THE SOUTHEASTERN COUNTIES BY 10Z. IMPRESSIVE DRYING BEHIND THE CONVECTION TOO AS NOTED BY NAM\S 850-500MB RH FIELD (5 PERCENT OVER WESTERN LAKE SUPERIOR AT 09Z). SO EXPECT SKIES TO QUICKLY CLEAR OUT. TEMPERATURES MUCH COOLER THAN THIS MORNING AND HAVE FOLLOWED CLOSE TO A BLEND OF THE MAV/MET GUIDANCE. WEDNESDAY...WITH UPPER MICHIGAN IN NW FLOW ALOFT BETWEEN A TROUGH OVER EASTERN CANADA AND AN UPPER RIDGE ACROSS ALBERTA...THE HIGH PRESSURE AREA OVER CENTRAL SASKATCHEWAN IS ALLOWED TO BUILD IN. AT 00Z...GFS/NAM HAVE THE HIGH OVER THE WESTERN U.P.. EXPECTING BREEZY CONDITIONS IN THE MORNING WITH THE BUILDING IN OF THE HIGH...THEN GRADUALLY DECREASING WINDS. WITH THE WINDS IN THE NE DIRECTION...AREAS ALONG LAKE SUPERIOR SHOULD BE QUITE COOL. HAVE READINGS IN AROUND 40 FOR THE SHORELINE. HOWEVER...WITH 850MB TEMPS AROUND 0C...INTERIOR LOCATIONS SHOULD STILL WARM UP QUITE NICELY...ESPECIALLY GIVEN THE DRY AIR MASS AND GREAT MIXING. HAVE PUT MID 50S HERE...BUT IT WOULD NOT BE OUT OF THE QUESTION OF HAVING A LITTLE HIGHER READINGS. WEDNESDAY NIGHT...COOL NIGHT IN STORE FOR UPPER MICHIGAN WITH THE HIGH OVERHEAD...CLEAR SKIES AND PRECIPITABLE WATER PROGGED AROUND 0.3 INCHES. HAVE DROPPED MINS CLOSER TO THE COLDER MAV GUIDANCE. THURSDAY...A SHRTWV TOPPLING THE WESTERN RIDGE WEDNESDAY NIGHT WILL MOVE INTO WESTERN ONTARIO AT 12Z THU AND INTO NORTHERN LAKE SUPERIOR AT 12Z FRI. AHEAD OF THE SHRTWV...850MB TEMPS CLIMB TO +2C...WHICH WITH THE DRY AIR MASS STILL AROUND...HIGH TEMPERATURE READINGS SHOULD TOP OUT NEAR 60 IN MANY LOCATIONS...ESPECIALLY IN THE WEST. THURSDAY NIGHT AND FRIDAY...SHRTWV AND ITS ASSOCIATED COLD FRONT CROSS UPPER MICHIGAN THURSDAY NIGHT...USHERING IN UNSEASONABLY COLD 850MB TEMP AIR. BY 12Z FRI...BOTH THE NAM AND GFS INDICATE 850MB TEMPS OF -8C OVER THE KEWEENAW. ALONG WITH THE FRONT COMES SOME STRONG 800-700MB FRONTOGENESIS...HOWEVER THERE IS NOT MUCH IN THE WAY OF MOISTURE TO WORK WITH. HAVE PLACED A CHANCE OF RAIN SHOWERS WITH THE FRONT...BUT ONLY A 30 POP. QPF FIELDS FROM THE GFS/NAM/UKMET ALL ONLY INDICATE A FEW HUNDREDTHS. BREEZY CONDITIONS WILL THEN FOLLOW FOR FRIDAY AS A 1033MB HIGH BUILDS SOUTH FROM MANITOBA. HAVE CUT TEMPERATURES BY 10 DEGREES GIVEN THAT 850MB TEMPS WILL BE IN THE -8C RANGE (CANADIAN ALSO SHOWS 1000-500MB THICKNESSES AROUND 530 DAM). THESE MAY NEED TO BE CUT EVEN MORE. EXTENDED...MODELS ARE NOW IN AGREEMENT OF HIGHLY AMPLIFIED FLOW WITHIN A POSITIVE PNA PATTERN...FAVORABLE FOR BRINGING COOL AND DRY AIR INTO THE GREAT LAKES. HAVE CUT TEMPS AND DEWPOINTS FOR FRIDAY NIGHT AND SATURDAY GIVEN THIS. WILL NEED TO WATCH TEMPS FOR BOTH FRIDAY NIGHT AND SATURDAY NIGHT AS THE HIGH PRESSURE AREA OVER MANITOBA ON FRIDAY MOVES INTO THE PLAINS AND WINDS DROP OFF. NO OTHER CHANGES WERE MADE TO THE REST OF THE EXTENDED. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 935 AM EDT MON APR 18 2005 .SYNOPSIS...MID/UPPER LEVELS CHARACTERIZED BY A DEEP TROUGH OVER THE INTERMOUNTAIN WEST AND RIDGE FROM THE GREAT PLAINS EWD. SURFACE RIDGE IS CENTERED OVER THE SOUTHEAST STATES, PROVIDING LIGHT WINDS. TEMPS WERE AROUND 60. SUBTROPICAL MOISTURE AND WEAK DISTURBANCE OVER THE LOWER MS VALLEY PRODUCING SCATTERED TO BROKEN MID/HIGH CLOUDS. THE 12 UTC TLH RAOB IS SLIGHTLY WETTER THAN PREVIOUS 24 HOURS (PWAT=0.44"), WITH LIGHT EASTERLY FLOW FROM THE SURFACE TO 700 MB. && .SHORT TERM (TODAY)...INHERITED ZONE FCST GENERALLY ON TRACK. WE'LL SEE CONSIDERABLE HIGH CLOUDS FOR THE REST OF TODAY, AND WILL CHANGE SKY TO "MOSTLY CLOUDY". 850 MB TO SURFACE DRY ADIABATS YIELD MAX TEMPS IN THE UPPER 70S TO LOWER 80S INLAND, WITH LOWER TO MID 70S NEAR THE COAST. && .MARINE...EAST TO SOUTHEAST WINDS GENERALLY 10 KNOTS OR LESS THIS MORNING, EXCEPT AT BUOY 42036 WHERE THEY WERE 10 TO 15 KNOTS DUE TO TIGHTER PRESSURE GRADIENT. THE RUC AND ETA PROGS INDICATE A SOUTHEAST WIND FROM 5 TO 10 KNOTS, EXCEPT BECOMING ONSHORE NEAR THE COAST DUE TO A WEAK AFTN SEA BREEZE. THE COASTAL WATERS FCST UPDATE WILL REFLECT THESE TRENDS. && .FIRE WEATHER...SUBSIDENCE BENEATH DEEP LAYER RIDGE WILL ALLOW DRIER AIR ALOFT TO MIX TO THE SURFACE LATER THIS MORNING. EXPECT AT LEAST 4 HOUR DURATIONS OF RH BELOW 35% FOR MOST INLAND FL ZONES THIS AFTN. WILL CONTINUE TO MONITOR RH VALUES THIS MORNING AND UPDATE AS NEEDED. && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...RED FLAG WARNING ALL ZONES NOON UNTIL SUNSET TODAY EXCEPT GULF AND FRANKLIN COUNTIES AND THE IMMEDIATE COAST. && $$ MAJ fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1002 AM EDT TUE APR 19 2005 .SHORT TERM (TODAY)...AS AXIS OF HIGH PRESSURE SLIDES EAST OVER THE COUNTY WARNING AREA THIS MORNING DO NOT EXPECT MANY CHANGES TO THE ONGOING FORECAST. FROM THE MORNING SOUNDINGS AND LATEST RUC HAVE DECIDED TO LOWER PERCENTAGE OF CLOUD COVER TO GIVE A MOSTLY SUNNY FORECASTS. WITH FLOW AT THE SURFACE EXPECTED FROM THE SOUTHWEST EXPECTING A RESULTANT SEA BREEZE NEAR THE COAST. TEMPERATURES LOOK FINE WITH MID 80S INLAND AND NEAR 70 AT THE BEACHES. && .AVIATION...ALL TERMINALS ARE VFR THIS MORNING AND EXPECTED TO REMAIN VFR THROUGH 12Z WEDNESDAY MORNING. WEAK PVA EXPECTED IN THE SHORT TERM...THUS EXPECT FEW TO SCATTERED CUMULUS AROUND 6K-7K MAINLY IN THE VICINITY OF THE SEABREEZE AROUND TIME OF MAX HEATING. THE SEABREEZE IS EXPECTED TO MOVE THROUGH MYR/CRE AROUND 15Z-16Z... AND AROUND 18Z-19Z AT ILM. THERE COULD BE A FEW GUSTS AT MYR/CRE TO 20-25 KNOTS LATE THIS AFTERNOON AROUND TIME OF MAX HEATING. WINDS EXPECTED TO DECREASE A FEW HOURS AFTER SUNSET. OTHERWISE...EXPECT ONLY SCATTERED PATCHES OF MID LEVEL CLOUDS 10K-14K...POSSIBLY BROKEN AT TIMES AFTER 06Z MAINLY AT ILM. && .MARINE...TRANQUIL CONDITIONS TO PERSIST ACROSS THE WATERS AS THE NEXT COUPLE DAYS WILL FEATURE A PATTERN RESEMBLING SUMMER. BUBBLE OF HIGH PRESSURE TO REMAIN OFFSHORE...AND SEA BREEZE INFLUENCES WILL DOMINATE. THIS WILL MEAN AN OSCILLATION BETWEEN LIGHT SW IN MOST IF NOT ALL AM HOURS...AND MORE LIKE DUE SOUTH 10-15 IN THE AFTERNOON AND EVENING HOURS. CURRENT FORECAST OF 2-3 FT SEAS LOOKS IN GOOD SHAPE. && .PREVIOUS DISCUSSION... (ISSUED 327 AM EDT TUE APR 19 2005) SHORT TERM (TODAY THROUGH WEDNESDAY NIGHT)... TEMPERATURES WELL ABOVE NORMAL AGAIN TODAY AS RIDGE CRESTS ACROSS THE AREA. EXPECT A SIGNIFICANT SEABREEZE FRONT AGAIN TODAY WITH WATER TEMPS ONLY NEAR 60 DEG. THIS SHOULD KEEP BEACH COMMUNITIES ABOUT 10 DEG COOLER. SIMILAR CONDITIONS ON WED. LOWS THROUGH WED NIGHT WILL ALSO BE ABOVE NORMAL AND IN THE MID AND UPPER 50S. LONG TERM (THURSDAY THROUGH MONDAY)... STILL LOOKING AT A COLD FRONT SLIPPING DOWN THE EAST COAST AND SHOULD MOVE THROUGH IN 08Z TO 13Z FRI. MODEST LIFT AND GOOD INSTABILITY AND SO WILL KEEP SMALL CHANCE OF SHOWERS AND THUNDER THU AFTERNOON AND NIGHT. STILL UNCERTAIN AS TO HOW FAR SOUTH THE COLD FRONT WILL GET ON FRI BEFORE STALLING. AT THIS POINT...KEEPING A SILENT 20 POP. LOW PRESSURE MOVING OUT OF THE TN VALLEY ON FRI AND ACROSS THE CAROLINAS FRI NIGHT AND FIRST PART OF SAT. GFS CONTINUES TO PICK UP THE PACE AS UPPER TROUGH IS FORECAST TO BE NO WHERE NEAR AS PRONOUNCED AS IT WAS 24 HRS AGO. AS LOW NEARS...WARM FRONTAL BOUNDARY SHOULD JUMP N OF THE AREA FRI NIGHT. DEEP AND MOIST SW FLOW SHOULD ENVELOP THE AREA. AT THIS POINT... THE HEAVIEST RAIN IS STILL EXPECTED N OF THE AREA ALONG AND AHEAD OF LOW PRESSURE. SHOULD SEE SOME ISENTROPIC RAIN DEVELOPING FRI NIGHT. THEN AS A VERY STRONG COLD FRONT APPROACHES FROM THE WEST...CONVECTION SHOULD DEVELOP ALONG AND AHEAD OF THIS FEATURE. WINDS UNIDIRECTIONAL...BUT WITH 50-60 KT MID LEVEL WINDS MAY SEE SOME STRONG THUNDERSTORMS...POSSIBLE SQUALL LINE IN WARM SECTOR. COLD FRONT SHOULD BARREL THROUGH HERE LATE SAT OR SAT EVE WITH STRONG DRYING AND ANOTHER COLD AIR INTRUSION. DID NOT GO AS COLD AS THE MEX NUMBERS FOR SUN...BUT A DRAMATIC COOL DOWN IS IN THE OFFING WITH TEMPS ON SUN BELOW NORMAL BY ABOUT 10 DEG. SHOULD BE FLIRTING WITH 40 DEG BOTH SAT AND SUN NIGHT. BUILDING RIDGE EARLY NEXT WEEK SHOULD BRING RETURN TO MILD SPRING LIKE CONDITIONS. AVIATION... VFR CONDITIONS THROUGH THE PERIOD. SHALLOW PATCHES OF PRE-DAWN MIST ARE POSSIBLE. MARINE... CURRENT BUOY DATA SHOWS THAT SEAS ARE PREDOMINANTLY COMPOSED OF A GENTLE E TO NE SWELL WITH ONLY MINIMAL WIND WAVE CONTRIBUTIONS DUE TO A LIGHT RETURN FLOW REGIME. NOT MUCH TO CHANGE OVER THE NEXT FEW DAYS SAVE FOR THE TAPERING OFF OF THE SWELLS. THAT SAID, LOOKS LIKE A STRETCH OF TRANQUIL BOATING WEATHER. THE GRADIENT MAY TIGHTEN SOME THURSDAY AS A FRONT SAGS DOWN FROM THE NORTH. HOW MUCH VEERING OCCURS IS SKETCHY AS IT IS TOUGH TO TELL HOW FAR SOUTH THE FRONT TRAVELS BEFORE IT BEGINS TO FEEL THE AFFECTS OF THE NEXT APPROACHING LOW. THIS LOW WILL DEEPEN AS IT APPROACHES, CAUSING A FURTHER TIGHTENING OF THE GRADIENT AND RESULTING WINDS ON FRIDAY NIGHT INTO SATURDAY. CAUTIONARY STATEMENTS LOOK LIKE A GOOD BET WITHIN THIS TIME FRAME. THERE IS FAIR AGREEMENT IN GUIDANCE WITH A STRONG COLD FRONTAL PASSAGE ON SATURDAY (TIME OF DAY STILL UNCERTAIN). && .ILM WATCHES/WARNINGS/ADVISORIES... NC...NONE. SC...NONE. MARINE...NONE. && $$ SHORT TERM...HAWKINS AVIATION...RAS MARINE...MRR nc AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 1006 AM CDT TUE APR 19 2005 .DISCUSSION... MAIN CONCERN FOR NEXT 24 HOURS IS THE TSRA CHANCES AND TEMPS THIS AFTERNOON. LARGE AREA OF LOW CLOUDS ACROSS SW MN AND NW IA ASSOCIATED WITH THE UPPER LOW. EXCEPT FOR A FEW LIGHT SHRA LATE THIS MORNING...PCPN SHOULD END ACROSS THE AREA WITH THIS SYSTEM. HOWEVER...DO EXPECT THAT CLOUDS WILL LINGER MUCH OF THE DAY IN THE FAR ERN CWA WHICH WILL HAMPER TEMPS. HAVE LOWERED TEMPS A COUPLE OF DEGREES IN NW TO ACCOURNT FOR LESS SUN. IN THE WEST...THINNER LOW DEC IN THE JAMES AND MISSOURI VALLEYS. LACK OF WIND AND SHALLOW INVERSION MAKING THESE CLOUDS HANG ON LONGER. HOWEVER DO EXPECT THAT SKIES WILL GO TO PARTLY CLOUDY BY EARLY AFTERNOON. SINCE PRIMARY FRONT HAS NOT GONE THROUGH...925 MB TEMPS REMAIN AROUND 20C THIS AFTERNOON ACCORDING TO THE RUC. THIS WOULD MIX OUT TO 80 DEGREES. HOWEVER...BELIEVE THAT SUN AND LIGHT NE FLOW WILL KEEP TEMPS IN THE MID 70S. DEW POINTS WILL REMAIN IN THE 50S THROUGH THE DAY. AS FOR CONVECTION...RIDGING IN WAKE OF UPPER WAVE IN SRN MN WL ACT TO ENHANCE CAP OVER NW IA. THERE IS UPPER Q-VECTOR DIV OVER THE AREA INDICATING FORCING FOR MID-LEVEL SUBSIDENCE WHICH WOULD PREVENT CAP FROM BEING ERODED FROM ABOVE. THIS...COMBINED WITH RELATIVELY COOL TEMPS...WILL MAKE IT DIFFICULT FOR CONVECTION TO INITIATE THIS AFTERNOON. THERERFORE HAVE LOWERED POPS TO SLIGHT CHC LATE AFTERNOON. IN SOUTH CENTRAL SD...UNR AND LBF SOUNDING SHOWS A ELEVATED MIXED LAYER AND RUC SUGGEST LAPSE RATES WILL APPROACH 8C/KM DURING THE LATE AFTERNOON. IN ADDITION...UPPER WAVE APPROACHES FROM WRN NEBRASKA WHICH WILL RESULT IN WEAK LIFT AT MID LEVELS HELPING TO ERODE CAP. IF THE TEMPS DO RISE INTO THE MID TO UPPER 70S...LITTLE CAP WILL REMAIN OVER SOUTH CENTRAL. THIS WOULD ALSO RESULT IN MLCAPES OVER 1000 J/KG. FINALLY WEAK CONVERGENCE EXISTS ALONG THE OLD FRONT TO ENHANCE LIFT IN THIS AREA. THEREFORE...EXPECT A FEW STORMS COULD PRODUCE HAIL TO 1 OR 1.25 INCHES DURING THE LATE AFTERNOON AND EARLY EVENING. HAVE ALSO RAISE POPS LATE AFTERNOON AND EARLY TONIGHT IN THIS AREA. .PREVIOUS DISCUSSION... LITTLE SPINNER VORTEX MOVING INTO MEAN RIDGE ACRS MS VALLEY...THRU EXTREME NWRN IA EARLY THIS MORNING...AND WITH IT A CONGLOMERATION OF SHOWER AND THUNDERSTORM BANDS WRAPPING TO E OF CENTER. PARENT TROUGH STILL WELL TO W WITH DISTINCT WAVES IN SWRN MT...AND LOTS OF ENERGY STILL DIGGING INTO AZ UNDER LOW IN NV. MAIN SFC FRONTAL BNDRY REMAINED WELL TO W OF CWA...FM KFAR TO KPHP...BUT WNDS WERE BEING INDUCED A BIT MORE NLY BY FIRST MENTIONED CLOSED LOW ACRS PARTS OF SERN SD. OF CONCERN FOR TODAY IS THE INITIAL PCPN DISTRIBUTION...THEN QUESTION OF ANY SEVERE THREAT FOR AFTN...AND FINALLY PCPN TIMING THRU REMAINDER OF SHORT TERM. LLJ HAS SUFFICIENTLY REPOSITIONED E OF THE CENTER...WITH DEEP WLY PUSH AT NLG PROFILER...TO MAKE ONE KEEP PCPN MENTION TO W OF CRNT LOCATION. TRACKING LOW CNTR...SEEMS ABOUT 3H TOO SLOW...EVEN ON 06Z NAM...AND WL THUS MOVE PCPN OUT A BIT FASTER THAN PREV. OTHERWISE... WL SEE STRATUS FIELD EXPAND EARLY THIS MORNING OVER MUCH OF CWA EXCEPT FAR W...BUT EVEN THERE...WL HAVE TO MENTION SOME FOG ACRS ELY UPSLOPE AREAS OUTSIDE STRATUS FIELD OVR SWRN CWA. SFC BNDRY WL CONTINUE TO MOVE SEWRD TDA...AND BY EARLY TO MID AFTN BE LOCATED ALG KSPW-KSUX LN. IS A FAIRLY CONVERGENT BNDRY...AND WITH OFF SFC DRY PUSH TO SW OF CLOSED LOW...SHUD BE ABLE TO FLUSH STRATUS OUT ENOUGH TO HEAT AND DESTABILIZE. HOWEVER...WITH LARGE SCALE TRENDING MORE TO THE RIDGING SIDE...EXPECT ENOUGH THREAT TO ONLY MENTION CHANCE MAINLY LTR AFTN. IN CONSIDERATION OF SEVERE THREAT...DEEP LAYER SHEAR IS FAIRLY LACKING AS MID LVL WNDS DROP TO 20 TO 25 KTS MAX. DRY OFF SFC PUSH WL LIKELY INCREASE THREAT FOR WND A BIT MORE...AND ALSO KEEP WET BULB ZERO DOWN FOR THREAT OF LARGE HAIL. WITH MULTICELLS GENERALLY FAVORED...ANY HAIL SHUD BE LIMITED TO QUARTER TO HALF DOLLAR AT MOST. TONIGHT...THREAT OF PCPN SHUD BE MAINLY ACRS SRN PARTS OF CWA...BUT DIFFICULTY RESOLVING DIFFERENCE IN INSTABILITY AND FORCING. MAIN DIV Q SLIDES OVR NRN CWA...BUT BEST INSTABILITY IS THRU MO RVR CORRIDOR. CLOSE ENOUGH THAT WL LKLY INDUCE PCPN FARTHER TO S...AND WL TAPER POPS FROM LOW CHC SHRA ACRS N...TO SCT SHRA/TSRA ACRS MO RVR. PCPN WL END IN THE MORNING ACRS S...WITH DRIER ELY/NELY PUSH TAKING OVR. NEXT SIG INITIATION OF CONVECTION EXPECTED TO BE OVER WRN HIGH PLAINS WED NIGHT AS PARENT UPPER SYSTEM BEGINS TO SHIFT TOWARD REGION. CORFIDI VECTORS WOULD THREATEN PROPOGATION TOWARD SCNTRL AREAS LTR IN NIGHT. A LOT COULD HAPPEN TO MAKE MDL SLNS NOT COME OUT IN THE WAY SHOWN RIGHT NOW...BUT IF HAD TO PUT A PERIOD OF HIGHER CONFIDENCE FOR PCPN...WOULD BE LTR THU INTO THU NIGHT AS HEALTHY INVERTED TROUGH MOVES ACRS CWA. IN THE EXTENDED RANGE...MADE AN ADJUSTMENT TO ALLOW COOLER TEMPERATURES ON SAT MORNING...AS STRONG PUSH OF COOLER AND DRIER HIGH PRESSURE EXPECTED...AND WAS TEMPTED TO REMOVE LOW CHC POPS FROM FRIDAY...BUT WITH SOME UNCERTAINTY TO TIMING EXIT OF REMNANTS OF WRN CLOSED LOW...WL LEAVE FOR FURTHER ANALYSIS. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SCHUMACHER/CHAPMAN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 1245 PM CDT TUE APR 19 2005 .DISCUSSION FOR MORNING GRIDS/ZONES... 330 AM CDT MAIN CONCERNS THROUGH THE FORECAST WILL BE PRECIP CHANCES BEGINNING THIS AFTERNOON ACROSS NORTHWEST PORTIONS OF CWA...THEN ACROSS REMAINDER OF THE AREA TONIGHT INTO WEDNESDAY. UPPER LEVEL CIRCULATION EVIDENT ON WATER VAPOR AND PROFILER DATA THIS MORNING CENTERED IN FAR NORTHWEST IOWA. THIS WAVE WILL CONTINUE TO LIFT EAST THROUGH MEAN UPPER RIDGE INTO WESTERN WISCONSIN TONIGHT. THIS WAVE WILL ENTER MID/UPPER LEVEL CONFLUENCE ZONE TONIGHT WITH ANOTHER WAVE KICKING THROUGH NORTHERN STREAM ACROSS SOUTHERN CANADA. NET EFFECT WILL BE TO DRAG LOW LEVEL BOUNDARY SOUTHEASTWARD WITH NAM/GFS PROGS IN REASONABLE AGREEMENT REGARDING TIMING OF COLD FRONT PASSAGE. DID REMOVE POPS ACROSS NORTHEAST ILLINOIS FOR THIS AFTERNOON. 00Z RAOB PLOTS SHOW SOME RELATIVELY DRIER AIR AT 850 HPA ACROSS LOWER MISSISSIPPI VALLEY WHICH RUC/NAM PROGS ADVECT INTO EASTERN ILLINOIS NORTHWEST INDIANA THIS AFTERNOON. MID LEVEL LAPSE RATES ALSO NOT ESPECIALLY STEEP WITH FORECAST SOUNDINGS STILL SHOWING MID LEVEL ISOTHERMAL LAYER...SO COMBINATION OF LACK OF LOW LEVEL MOISTURE AND MARGINAL LAPSE RATES SHOULD KEEP THINGS DRY ACROSS MOST OF CWA THIS AFTERNOON. DID KEEP SOME LOW CHANCE POPS FOR TSRA ACROSS FAR NORTHWEST THIS AFTERNOON WITH SOME BETTER LOW LEVEL MOISTURE IN THIS AREA AND WEAKER INHIBITION. ANOTHER WARM DAY IN STORE WITH TEMPS RISING INTO THE UPPER 70S TO LOWER 80S. FOR TONIGHT LOW LEVEL BOUNDARY SHOULD SAG TO WI/IL BORDER BY WEDNESDAY MORNING WITH INCREASING LOW LEVEL FRONTOGENESIS AND INCREASING LOW LEVEL MOISTURE POOLING NEAR THE BOUNDARY. WILL UP POPS TO LIKELY ACROSS FAR NORTHWEST AND CARRY LIKELY POPS FROM NORTH TO SOUTH ON WEDNESDAY WITH SOUTHWARD PROGRESSION OF THE FRONT. BRUNT OF CAA RELATIVELY SHALLOW SETTING UP DECENT FRONTAL INVERSION ON WEDNESDAY BUT STRENGTH OF LOW LEVEL CAA SHOULD PROMOTE DOWNWARD TEMP TREND ON WEDNESDAY WITH AREAS ALONG THE LAKE PROBABLY DIPPING BACK INTO UPPER 40S IN THE AFTERNOON. SOME DECENT SURFACE BASED INSTABILITY FOR AREAS WELL SOUTH OF INTERSTATE 80 ON WEDNESDAY. GIVEN TIMING OF FROPA...COULD SEE FEW STRONG STORMS ACROSS FAR SOUTHERN CWA WEDNESDAY AFTERNOON BUT BETTER THREAT DOES APPEAR TO BE JUST SOUTH OF THE AREA. GFS/NAM SOLUTIONS DIVERGE SOMEWHAT FOR FRIDAY WITH NAM BRINGING IN MORE SIGNIFICANT ISENTROPIC LIFT AS MORE AMPLIFIED UPPER WAVE ACROSS WESTERN CONUS ENTERS INTO MID MS VALLEY. GFS SUPPRESSES THIS LIFT FURTHER TO THE SOUTH WITH MORE PRONOUNCED SHORT WAVES RIDING THROUGH THE NORTHERN STREAM. MADE VERY FEW CHANGES TO THIS PERIOD AND WILL KEEP CHANCE OF RAIN SHOWERS GOING FROM LATE THURSDAY NIGHT INTO FRIDAY. MAIN CHANGE TO LONGER RANGE FRI-MON PERIOD WAS FOR COOLER CONDITIONS AS UPPER FLOW TRANSITIONS TO MORE AMPLITUDE WITH EASTERN CONUS TROUGH AND RIDGING OVER THE ROCKIES. THIS WILL RESULT IN TEMPS AT OR SLIGHTLY BELOW SEASONAL NORMS THROUGH MUCH OF THE WEEKEND. GFS/CANADIAN HAVE BEEN SOMEWHAT CONSISTENT WITH STRONGER NORTHERN STREAM WAVE DROPPING INTO UPPER MS VALLEY SUNDAY INTO MONDAY AND WILL MAINTAIN SHOWER CHANCES FOR THIS PERIOD ALSO. NDM && .AVIATION... 1245 PM CDT WELL DEVELOPED MID LVL CIRCULATION CONTS TO SLOWLY LIFT NEWRD FM SRN MN WITH MAIN RA/TSRA CONCENTRATED IN N THRU E QUADRANTS OF CIRCULATION...AND A NARROW LN OF SHRA EXTENDIND SWWRD ACORSS N CNTRL IA AHEAD OF CDFNT. EXC FOR KRFD...ANY SIG THREAT OF SHRA/TSRA EXPECTED TO HOLD OFF WELL INTO OVRNGT TIL LLVL CONVERGENCE OF INCRGLY MOIST AIR SPREADS EWRD ACROSS NRN IL AHEAD OF CDFNT SETTLING SWRD INTO SRN WI. AT KRFD...EDGE OF UPR 50S-LWR 60S SFC DWPT PLUME OUT OF SRN PLAINS WILL CONT TO SHIFT EWRD ACROSS MS RIVER THIS AFTERNOON. MENTIONED CB AT LATE AFTERNOON AS MAY BE A FEW STARTING TO MOV INTO AREA BUT PROBABILITY THOUGHT TO BE TOO LOW FOR EVEN VCTS AT THAT TM BUT BY 06Z EXPECT SHRA AND SOME TSRA TO MOVE IN. PRES GRADIENT CONT TO TIGHTEN THIS AFTERNOON AND WITH GOOD SFC HEATING WILL MIX DOWN MOMENTUM FROM 25-30KT WNDS AT 1-3K FT AGL. WNDS TO DROP OFF AND GUSTINESS DIMINISH WITH SUNSET. CFP WED MORNING VEERS WIND TO NW AND N BY 18Z AS SFC RDG BUILDS ACROSS NR PLAINS...UPR MIDWEST...NRN GRTLKS. TRS && .LOT...WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LK MI...NONE. $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 415 PM EDT TUE APR 19 2005 .DISCUSSION... MAIN FCST CONCERNS ARE PROGRESSION AND ENDING OF SHRA/TSRA TONIGHT AND THEN POTENTIAL OF SHRA WITH NEXT COLD FROPA FRI. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A LARGE UPPER LOW DOMINATING THE WRN STATES WITH A BROAD RIDGE OVER MUCH OF THE CNTRL/ERN CONUS. A SHORTWAVE TROF EXTENDS FROM WRN QUEBEC ACROSS ONTARIO AND MANITOBA...AND A COMPACT SHORTWAVE WAS CENTERED NEAR KMSP. AT THE SFC...COLD FRONT ASSOCIATED WITH SHORTWAVE TO THE N EXTENDS FROM S OF JAMES BAY TO JUST N OF LAKE SUPERIOR AND THEN INTO NRN MN. SHRA/TSRA HAVE BEEN DEVELOPING S OF FRONT IN UNSTABLE AIRMASS. 12Z KINL SOUNDING SHOWED ELEVATED CAPE VALUES AROUND 1200 J/KG FOR A PARCEL LIFTED FROM ABOUT 750MB. SO IT WASN'T MUCH OF A SURPRISE TO SEE DECENT TSRA ACTIVITY OVER THE COLD/STABLE MARINE LAYER OF WRN LAKE SUPERIOR SINCE LATE MORNING. A LARGE CLUSTER OF SHRA/TSRA IS OCCURRING WITH SHORTWAVE NEAR KMSP WITH PCPN HEADING ENE. MODELS ARE IN GOOD AGREEMENT ON HEIGHT FALLS ACROSS ONTARIO/QUEBEC TONIGHT AS SHORTWAVE CONTINUES E. THIS WILL HELP FORCE COLD FRONT THRU UPPER MI DURING THE EVENING. MEANWHILE...SHORTWAVE NEAR KMSP WILL HEAD TOWARD KGRB. SIMPLE EXTRAPOLATION OF SHRA ASSOCIATED WITH SHORTWAVE INDICATES SCNTRL UPPER MI WILL GET INTO THE MORE WIDESPREAD PCPN ASSOCIATED WITH IT. TO THE N...EXPECT NUMEROUS SHRA AND A FEW TSRA TO DROP S ACROSS FCST AREA THIS EVENING IN ASSOCIATION WITH COLD FRONT. ATLHOUGH NAM 0-3KM MUCAPE IS 600-1200J/KG...DEEP LAYER SHEAR ON THE ORDER OF 15-25KT SHOULD PREVENT MUCH IN THE WAY OF STORM ORGANIZATION FOR SVR WX. MIGHT BE SOME SMALL HAIL FROM ISOLATED STRONGER STORMS...BUT IN GENERAL... WOULD EXPECT ACTIVITY ALONG THE LINES OF WHAT HAS BEEN SEEN SO FAR TODAY FROM WRN LAKE SUPERIOR INTO WRN UPPER MI. 12Z MODELS ARE A BIT SLOWER WITH THE DRYING/SUBSIDENCE TONIGHT...BUT STILL LOOKS LIKE SHRA SHOULD END BY 06Z OVER NW AND AROUND 09Z OVER THE SE. SHRA OVER LAKE SUPERIOR WILL PROBABLY RESULT IN FOG DEVELOPING OVER THE LAKE. IF FOG DOES DEVELOP...IT WILL COME ONSHORE AS WINDS SHIFT AROUND TO THE N OR NE THIS EVENING. SFC HIGH PRES BUILDS INTO THE UPPER LAKES WED AFTN/NIGHT. FCST SOUNDINGS SHOW STRONG DRYING WED ABOVE BOUNDARY LAYER...ESPECIALLY NAM. MIGHT BE SOMEWHAT OPTIMISTIC CONSIDERING THE MASS OF STRATOCU PRESENT THIS AFTN ACROSS ERN MANITOBA AND WRN ONTARIO. IN ADDITION...THERE MAY BE LINGERING FOG/STRATUS COMING OFF LAKE SUPERIOR IN THE MORNING. WILL THUS TREND SKY CONDITION TOWARD MOSTLY SUNNY ONLY BY LATE AFTN ALL AREAS AS HIGH PRES APPROACHES AND LOW-LEVEL FLOW BECOMES MORE DIVERGENT. SHOULD BE BREEZY A DAY... ESPECIALLY E HALF OF FCST AREA WITH NRLY 950MB WINDS A SOLID 20KT AHEAD OF APPROACHING HIGH. IT WILL ALSO BE CHILLY NEAR LAKE SUPERIOR...PROBABLY HIGHS NO BETTER THAN THE LWR 40S. HAVE STAYED CLOSE TO GOING FCST FOR THE WARMER SW AREAS (LOW-MID 50S). HIGH PRES SETTLES OVER UPPER MI WED NIGHT FOR A COOL NIGHT. SINCE MIN PRECIPITABLE WATER AXIS (UNDER 0.3 INCHES) PASSES S OF THE AREA BY LATE EVENING...TEMP FALL SHOULD NOT GET OUT OF HAND. GUIDANCE NUMBERS ARE SIMILAR...BUT HAVE FAVORED THE GENERALLY COOLER FWC GUIDANCE. SHORTWAVE DROPPING DOWN FRONT SIDE OF WRN CANADA RIDGE ARRIVES IN WRN ONTARIO THU AFTN WITH ASSOCIATED SFC COLD FRONT REACHING WRN LAKE SUPERIOR LATE IN THE DAY. AIRMASS WILL BE TOO DRY TO SUPPORT ANY PCPN THU. WITH WAA PUSHING 850MB TEMPS UP TO AROUND 2C...HIGHS SHOULD TOP OUT WELL INTO THE 50S AND TO AROUND 60 OVER THE W. WITH 950MB WINDS ONLY AROUND 10KT AT 18Z PER GFS/NAM...THERE WILL LIKELY BE SOME LOCAL COOLING NEAR THE GREAT LAKES. COLD FRONT PASSES ACROSS UPPER MI THU NIGHT/EARLY FRI...USHERING IN UNSEASONABLY COLD AIR. 850MB TEMPS PLUNGE TOWARD -7/-8C ON NAM (-10C ON GFS WHICH IS PROBABLY A BIT EXTREME) OVER ABOUT THE NW HALF OF UPPER MI DURING THE DAY FRI. CAA AND NRLY 950MB WINDS OF 20-30KT SUGGEST A VERY CHILLY DAY NEAR LAKE SUPERIOR (HIGHS PROBABLY AROUND 40 AT BEST). EVEN INLAND...TEMPS NOT EXPECTED TO CLIMB OUT OF THE 40S...BUT THAT WILL DEPEND ON TIMING OF FRONT. IF FRONT IS A BIT SLOWER PER NAM SOLUTION...HIGHS WILL REACH THE 50S OVER THE S BEFORE FALLING OFF A BIT IN THE AFTN. HAVE INCLUDE A CHANCE OF -SHRA THU NIGHT/EARLY FRI AHEAD OF FRONT. DAYTIME INSTABILITY MAY RESULT IN SOME -SHRA/SPRINKLES FRI AS UPPER TROF ROTATES ACROSS THE AREA. IN FACT...850MB TEMPS AND 1000-850MB THICKNESS SUPPORT FLURRIES/GRAUPEL AS WELL. WILL LEAVE OUT FOR NOW SINCE BOUNDARY LAYER MAY START OUT FAIRLY WARM FRI BEFORE CAA REALLY KICKS IN. SAT-TUE...MODELS ARE IN GOOD AGREEMENT ON A HIGHLY AMPLIFIED PATTERN DURING THIS PERIOD WITH PRONOUNCED RIDGING THRU WRN CANADA AND TROFFING OVER THE ERN CONUS. THIS MAY BE A PATTERN THAT HOLDS THRU THE END OF THE MONTH PER CPC OUTLOOK. SO A PROLONGED STRETCH OF GENERALLY BELOW NORMAL TEMPS IS ON THE WAY. 00Z/06Z GFS AND 00Z ECMWF ARE IN VERY GOOD AGREEMENT WITH THE PATTERN OVER THE WEEKEND AS IT PERTAINS TO THE UPPER LAKES REGION. DEEP TROF/CLOSED LOW WILL BE HEADING TO THE E COAST SAT/SUN WHILE ANOTHER STRONG SHORTWAVE DIVES DOWN FRONT SIDE OF WRN RIDGE INTO THE UPPER MIDWEST. UKMET/CANADIAN ARE QUITE A BIT WEAKER WITH THE SYSTEM DROPPING TOWARD THE UPPER MIDWEST. WHILE THE GFS/ECMWF TRENDS ARE STRONGER WITH THIS SYSTEM...THE GFS ENSEMBLE MEAN IS WEAKER THAN OPERATIONAL RUNS WHICH WOULD TYPICALLY BE EXPECTED. GIVEN AGREEMENT OF ECMWF/GFS OPERATIONAL RUNS...WILL FAVOR THEIR SOLUTION TODAY WHICH IS SIMILAR TO HPC THINKING. ORIGINALLY THOUGHT GOING DRY FCST FOR SAT WAS IN GOOD SHAPE...BUT 12Z UKMET/GFS/CANADIAN HAVE DEEPENING ERN TROF CLOSE ENOUGH THAT AFTN INSTABILITY MAY POP A FEW SHRA. HAVE KEPT MENTION ONLY OVER THE E HALF OF FCST AREA FOR NOW. WITH 850MB TEMPS RUNNING -3 TO -5C PER 00Z GFS/ECMWF...WILL BE A COOL DAY... ESPECIALLY NEAR LAKE SUPERIOR WITH LINGERING GRADIENT FLOW ACROSS THE LAKE (40S NEAR THE LAKE TO AROUND 50 INLAND). SHOULD BE A BIT WARMER SUN AHEAD OF APPROACHING SHORTWAVE...AND WILL MAINTAIN GOING CHC OF -SHRA AS SYSTEM APPROACHES. EXPECT COOL AND UNSETTLED CONDITIONS MON/TUE AS MEAN TROF POSITION SHIFTS TO WRN LAKES REGION PER GFS/ECMWF. SHOULD BE SCT SHRA BOTH DAYS WITH PEAK COVERAGE IN THE AFTN HRS DUE TO DAYTIME HEATING/INSTABILITY UNDER COLD AIR ALOFT. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 344 PM EDT TUE APR 19 2005 .SHORT TERM... THERE ARE TWO SYSTEMS WE ARE WATCHING WITH THIS FORECAST PACKAGE. FIRST IS THE SHORTWAVE MOVING FROM MN TO WI AT 18Z IN COMBINATION WITH THE NRN STREAM COLD FRONT HEADING SOUTH WITH NORTHERN STREAM JET (CURRENTLY OVER SRN CANADA). THIS WILL BE THE WEATHER MAKER FOR TONIGHT INTO WEDNESDAY. THE SECOND SYSTEM IS A COMBINATION EVENT FOR FRIDAY. A SHORTWAVE GETS KICKED OUT OF THE WESTERN CLOSED UPPER AND TRIES TO PHASE WITH A DIGGING NORTHERN STREAM SHORTWAVE. THIS WILL BRING MUCH COLDER WEATHER TO WEST MICHIGAN FOR THIS COMING WEEKEND. FOR TONIGHT...I FAVOR THE GFS SINCE IT HOLDS ON TO MN SHORTWAVE BETTER THAN THE NAM DOES. THIS IS SUPPORTED BY THE 18Z SFC WEATHER IN THAT THERE REALLY IS STILL A COHERENT SURFACE LOW OVER SE MN AS FORECAST BY THE GFS. ALSO THE SATELLITE AND RADAR LOOPS SEEM TO FAVOR A MORE NORTHERN TRACK OF THE SURFACE WEATHER. ANOTHER CONSIDERATION IS THE COLD FRONT DROPPING DOWN FROM SOUTHERN CANADA INTERACTING WITH THE SOUTHERN STREAM WAVE. THAT WOULD FAVOR A MORE NORTHERN TRACK OF MOST OF THE PRECIPITATION. THE RESULT OF ALL THIS IS THE BEST INSTABILITY WILL BE LONG GONE BEFORE THE ACTIVITY REACHES WEST MICHIGAN AROUND MIDNIGHT. THERE IS SOME ELEVATED INSTABILITY BUT WHAT CAPE THERE IS...IS RATHER NARROW. STILL THERE IS A GOOD MOISTURE FEED WITH THIS SYSTEM. PRECIPITABLE WATER VALUES ARE NEARLY 1.3 INCHES WITH THIS AND BOTH THE NAM AND FLS RUC BRING THAT INTO SOUTHWEST LOWER MICHIGAN BY MIDNIGHT OR SO. THUS IS WILL RAIN! SO I HAVE CONDITIONAL POP NORTH OF INTERSTATE 96 AFTER MIDNIGHT AND LIKELY SOUTH OF INTERSTATE 96. THE THREAT FOR SEVERE IS MINIMAL. THAT IS DUE TO THE LATE HOUR WHEN THE UPPER WAVE WILL BE MOVING THROUGH AND THE FEEBLE AMOUNTS OF ELEVATED CAPE ASSOCIATE WITH THE SYSTEM. THERE IS DECENT LOW LEVEL SHEAR (LOWEST 1 KM) BUT NOT MUCH ELSE. THE DEEP SHEAR IS REALLY FEEBLE...MOSTLY LESS THAN 25 KNOTS. SO THIS WILL BE MOSTLY MODERATE TO HEAVY RAIN SHOWERS WITH ISOLATED THUNDERSTORMS. NOT TO MUCH RISK OF WIND DAMAGE DUE TO ELEVATED CONVECTION EVEN THOUGH THERE IS A 40 KNOT LOW LEVEL JET FEEDING THE INFLOW (NEAR I-94 AFTER MIDNIGHT). WEDNESDAY THE COLD FRONT DROPS SOUTH AND THE ENTRANCE REGION TO THE NORTHERN STREAM JET WILL SLOW THE FRONT DOWN AND RESULT IN AN AMPLIFICATION OF THE SURFACE LOW ASSOCIATED WITH THE SRN STREAM WAVE. THUS I CONTINUED LIKELY POP ACROSS THE CWA IN THE MORNING AND END THE ACTIVITY FROM NORTH TO SOUTH IN THE AFTERNOON. SINCE THE FRONT DOES NOT GET THOUGH GRR TILL AFTER 15Z... KEEP THE THUNDER GOING INTO EARLY AFTERNOON SOUTHEAST. TO MUCH CLOUDS FOR ANY SEVERE WEATHER WITH THIS THOUGH. CLEARING FOLLOWS TUESDAY NIGHT FROM NORTH TO SOUTH. MUCH COOLER TOO. LOWS WELL DOWN INTO THE 30S. A CANADIAN HIGH WILL BRING NORTHEAST WINDS AND MOSTLY CLEAR SKIES ON THURSDAY. COOLER TOO. HIGHS WILL BE LUCKY TO REACH 60F. FRIDAY... A WAVE SHEARING OUT OF THE WESTERN CLOSED UPPER LOW WILL TRY TO PHASE WITH A DIGGING NORTHERN STREAM WAVE. THIS SHORTWAVE TRIES TO PULL THE POLAR VORTEX SOUTH AND WEST WHICH RESULTS IN STRONGLY FALLING 500MB HEIGHTS FRIDAY. THAT RESULTS IN FALLING THICKNESS FIELDS. GIVEN ALL OF THAT... IF FIGURE ONE WAY OR THE OTHER WE SHOULD GET SOME SHOWERS FROM THIS SET UP. THE GFS SET UP IS MORE BELIEVABLE. .LONG TERM... AN UPPER TROF SHOULD BE OVER LAKE MICHIGAN FRIDAY NIGHT. THE MODELS ARE IN GOOD AGREEMENT THAT A CLOSED UPPER LOW WILL DEVELOP AS THIS SYSTEM CROSSES THE GREAT LAKES ON SATURDAY. THE LOW WILL BECOME VERTICALLY STACKED OVER THE EASTERN GREAT LAKES. THIS WILL LEAVE MICHIGAN IN A COOL AND UNSETTLED PATTERN INTO THE WEEKEND AND CONTINUING INTO NEXT WEEK. THEREFORE WILL ADD PCPN CHCS TO FRIDAY NIGHT AS THE WAVE PASSES AND ALSO INCLUDE SHOWERS ON SATURDAY AS THE COLD AIR ALOFT SHOULD PRODUCE SCATTERED DIURNAL SHOWERS. TOUGH CALL AS TO HOW QUICK THIS SYSTEM WILL BE FAR ENOUGH TO EAST TO END THE SHOWERS. WILL COUNT ON RIDGING TO BUILD INTO THE AREA BY SUNDAY AND GO DRY INTO MONDAY. ANOTHER UPPER LOW DRIFTS ACROSS THE MIDDLE OF THE NATION AND IS PROGGED TO BE NEAR STL BY TUESDAY...SO WILL CARRY POPS. WILL AGAIN TREND A BIT COOLER FOR SATURDAY AS THE CLOUDS AND SHOWERS LINGER...OTHERWISE MAX TEMPS SHOULD BE IN THE MID AND UPPER 50S. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WDM JK mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 255 PM EDT TUE APR 19 2005 .SHORT TERM (TONIGHT THROUGH THURSDAY)... ISOLD -SHRA/-TSRA POPPING THIS AFTN AS TEMPS HAVE REACHED MRNG SNDING CONVECTIVE NMBRS UNDR MID LVL RIDGE AXIS. XG SHRTWV WHICH SPPRTD MRNG SPRINKLES ALSO SLOW TO EXIT AS PER LATEST RUC RUN. AT ANY RATE...THESE SHOULD FADE WITH THE SUN WITH THE REST OF THE NGT AND MUCH OF WED RMNG MILD. SIGNIFICANT CDFNT STILL EXPECTED WED EVE WITH SHRA/TSRA CHCS INCRSG THRU LATE AFTN AS THIS FEATURE APPRCHS. SITUATION WL HAVE TO MONITORED FOR SVR WITH DECENT SHEAR PROFILE IN THE MID LVLS EXPECTED AS NW FLOW DVLPS...HOWEVER INSTABILITY CURRENTLY LKS TO BE LACKING UNTIL MSTR RTNS LATE IN THE DAY...POSSIBLY TOO LATE FOR THE SVR. SPC PLACED THE AREA UNDR SLGT RISK AS OF 18Z. && .LONG TERM (FRIDAY THROUGH TUESDAY)... 12Z GFS SHOWS DEEPENING UPPER TROUGH SWINGING THROUGH GREAT LAKES LATE FRIDAY WITH LOW CLOSING OFF OVER WESTERN PA LATE SATURDAY. ASSOCIATED SURFACE LOW TRACKS SOUTH OF OUR FORECAST AREA FRIDAY NIGHT AND SATURDAY...THEN MOVES INTO NEW ENGLAND SUNDAY. MENTIONED CHANCE OF SHOWERS BEGINNING LATE FRIDAY AND CONTINUING THROUGH THE WEEKEND. PRECIPITATION COULD MIX WITH SNOW NORTH AND IN THE MOUNTAINS SATURDAY NIGHT WITH TEMPERATURES IN THE LOW 30S. STILL A CHANCE OF SHOWERS EARLY NEXT WEEK AS NEXT SYSTEM MOVES INTO THE MIDDLE MS VALLEY BY TUESDAY. && .AVIATION... AREA OF MIDDLE CLOUDS CONTINUES TO SLIDE EAST INTO CENTRAL PA. VISIBLE SATELLITE IMAGERY SHOWS SCATTERED CUMULUS HAVE FORMED ACROSS MOST OF FORECAST AREA AND RADAR NOW DETECTING ISOLATED SHOWERS AND THUNDERSTORMS POPPING UP. AREAL COVERAGE SHOULD REMAIN SMALL THROUGH THE REST OF THIS AFTERNOON...BUT CONDITIONS MAY BRIEFLY LOWER TO MVFR IN ISOLATED SHOWERS. MAINLY VFR CONDITIONS SHOULD CONTINUE TONIGHT AND WEDNESDAY. SCATTERED CUMULUS SHOULD FORM AROUND 4000 FT BY MID MORNING WITH SOUTHWEST SURFACE WINDS INCREASING TO 15 TO 25 KT BY MIDDAY WEDNESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ 15 pa