AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LITTLE ROCK AR 930 AM CDT FRI MAY 14 2004 ...UPDATE OUT ALREADY... RADAR ECHOES ARE OPPOSITE THE POPS...SO UPDATED THE FORECAST TO KEEP A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FIRST PERIOD STATEWIDE. RUC SHOWS WEAK SHORT WAVE SUPPORTING THE CURRENT ACTIVITY. && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 32 ar AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU MAINE 1020 EDT FRI MAY 14 2004 .UPDATED....TEMPS ACROSS DOWNEAST ZONES A BIT COOLER THAN PREVIOUSLY EXPECTED. WILL LOWER TEMPS ACROSS ZONES 15-17...29...30. OTHER WISE THE PREVIOUS FORECAST LOOKS GOOD. .SYNOPSIS...MOSTLY CLEAR SKIES THIS EVENING WILL ALLOW FOR FOG AND STRATUS TO DEVELOP ACROSS THE REGION TONIGHT AS TEMPERATURES COOL. A COLD FRONT WILL ENTER NORTHWEST MAINE SATURDAY AFTERNOON AND MOVE THROUGH THE STATE AND THEN OFF THE COAST BY SATURDAY EVENING. HIGH PRESSURE WILL RETURN FOR SUNDAY AND MONDAY. DISCUSSION... SHORT TERM (TONIGHT-SUNDAY NIGHT): WARM FRONT ABOUT TO CLEAR THE STATE THIS AFTERNOON WITH MOST AREAS RECEIVING PLENTY OF SUN EXCEPT FOR EXTREME NORTHERN MAINE AND THE SOUTHEAST CORNER OF THE STATE.SCATTERED SHOWERS A POSSIBILITY ALONG THE WESTERN BORDER WITH QUEBEC THIS AFTERNOON INTO EARLY THIS EVENING DUE TO SOLAR HEATING AND OROGRAPHIC LIFT. BUFKIT RUC SOUNDING INDICATING TT OF 50 AND K INDEX OF 35 WITH PW OF OVER AN INCH. DEVELOPMENT ALREADY TAKING PLACE WITH SCATTERED SHOWERS FROM NORTHERN MAINE TO CHAMBERLAIN LAKE. EXPECT ACTIVITY TO DIE DOWN AFTER SUNSET WITH THE LOSS OF SOLAR HEATING. LOW CLOUDS AND FOG TO DEVELOP OVER OUR CWA BEFORE MIDNIGHT AS SOUTHERLY LOW LEVEL MOIST FLOW COOLS. AREAS OF FOG AND STRATUS WILL LIFT DURING THE MORNING GIVING MOST AREAS SOME SUN BY LATE MORNING. COLD FRONT WILL ENTER NORTHWEST MAINE MID AFTERNOON AND THEN OFF THE COAST BEFORE MIDNIGHT. SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG A PRE FRONTAL TROUGH CROSSING THE NORTH EARLY IN THE AFTERNOON...ACROSS CENTRAL MAINE BY MID AFTERNOON AND THEN ACROSS SOUTHERN SECTIONS DURING THE LATE AFTERNOON. CAPE VALUES VERY LOW ACROSS THE NORTH BUT JUST OVER 1000 JOULES ACROSS THE SOUTHERN SECTIONS. HIGH PRESSURE WILL RIDGE ACROSS THE REGION SATURDAY NIGHT AND THEN MOVE NORTH OF THE STATE ON SUNDAY. WITH ZONAL FLOW ALOFT...FRONT WILL STALL OVER THE GULF OF MAINE AND CLOUDS MAY LINGER ACROSS SOUTHERN SECTIONS UNTIL MIDDAY SUNDAY. SHORTWAVE RIDGE WILL BUILD ACROSS THE STATE SUNDAY NIGHT INTO MONDAY WITH MOSTLY CLEAR SKIES. LONG TERM (MONDAY INTO FRIDAY): LEANED W/A CONSENSUS OF ETA/GFS & GEM FOR MONDAY INTO TUESDAY AS HIGH PRES BUILDS E INTO THE CANADIAN MARITIMES, EH. SOME CONCERN IS THERE FOR SOME DAMMING/WEDGING TO SET UP W/HIGH FCST TO BE ENE OF THE REGION. HINTED AT THIS IN GRIDS FOR MON W/MORE CLOUDS ACROSS NNE PORTION OF THE CWFA. FURTHER S...SHOULD BE ABLE TO GET AWAY W/PC CONDITIONS. TEMPS WILL BE TRICKY IF THIS SCENARIO PANS OUT. DID MAKE SOME ADJUSTMENTS TO MONDAY'S MAXES. NEXT FRONTAL BOUNDARY APPROACHES LATE TUESDAY INTO WEDNESDAY W/A ROUND OF SHOWERS. ATTM...DECIDED TO LEAVE ANY MENTION OF TSRA OUT GIVEN IT IS DAYS 4 & 5. STILL PLENTY OF TIME TO ASSESS THINGS. PLUS...IF DAMMMING/WEDGE DOES TAKE PLACE...THEN CONVECTION WILL BE LIMITED STABLE LLVLS. NOT BUYING INTO THE WAD OF QPF THAT THE GFS IS SHOWING GIVEN LACK OF SIGNIFICANT MOISUTRE TRANSPORT. FRONT IS FORECAST TO CLEAR THE COAST WED AFTERNOON WITH HIGH PRES BUILDING INTO THE REGION ON THURSDAY PROVIDING FOR DECENT WX. TEMPS ARE A REFLECTION OF THE MRF/MEX W/USUAL ADJUSTMENTS. MARINE: HAVE STAYED CLOSE TO ETA12 WINDS THROUGH 12Z MONDAY. FOR THE REMAINDER OF THE FORECAST HAVE MODIFIED GFS WINDS DOWN TO BETTER FIT LOWER STABLE LAYER. TEMPERATURE DEW POINT SPREAD AT 44027 STILL AROUND 6 DEGREES AND IS NOT CHANGING VERY MUCH. SUSPECT WE WILL HAVE TO WAIT UNTIL LATER THIS AFTERNOON FOR STRONGER SOUTHERLY FLOW BEFORE FOG DEVELOPS. LOOKING FOR FOG ACROSS THE WATERS TONIGHT THROUGH SATURDAY...THEN VISIBILITY IMPROVING EARLY SATURDAY NIGHT AS WINDS SHIFT INTO THE SOUTHWEST BRINGING IN DRIER AIR. HAVE INITIALIZED GRIDS WITH WNA WAVE WATCH III. HAVE LOWERED WAVE HEIGHTS 1 TO 2 FT BELOW WAVE MODEL NUMBERS TO BETTER FIT WINDS IN STABLE LAYER ACROSS OUR WATERS THROUGH SATURDAY. EXPECT MOST OF WAVES SATURDAY FROM SOUTH OF THE GULF OF MAINE WHERE WINDS ARE MIXING DOWN BETTER. AVIATION: VFR CONDITIONS WILL DETERIORATE TO MVFR CONDITIONS AT ALL TAF SITES THIS EVENING. CLEARING SKIES...WET GROUND & SLY FLOW WILL LEAD TO THE POTENTIAL FOR IFR CONDITIONS BOTH FOR CIGS/VSBYS AFT 07Z. .CAR...NONE. NEAR TERM/AVIATION: WOLFE SHORT TERM/MARINE: FOSTER LONG TERM/MARINE: HEWITT UPDATE: NORTON me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU MAINE 341 PM EDT FRI MAY 14 2004 .SYNOPSIS...MOSTLY CLEAR SKIES THIS EVENING WILL ALLOW FOR FOG AND STRATUS TO DEVELOP ACROSS THE REGION TONIGHT AS TEMPERATURES COOL. A COLD FRONT WILL ENTER NORTHWEST MAINE SATURDAY AFTERNOON AND MOVE THROUGH THE STATE AND THEN OFF THE COAST BY SATURDAY EVENING. HIGH PRESSURE WILL RETURN FOR SUNDAY AND MONDAY. DISCUSSION... SHORT TERM (TONIGHT-SUNDAY NIGHT): WARM FRONT ABOUT TO CLEAR THE STATE THIS AFTERNOON WITH MOST AREAS RECEIVING PLENTY OF SUN EXCEPT FOR EXTREME NORTHERN MAINE AND THE SOUTHEAST CORNER OF THE STATE.SCATTERED SHOWERS A POSSIBILITY ALONG THE WESTERN BORDER WITH QUEBEC THIS AFTERNOON INTO EARLY THIS EVENING DUE TO SOLAR HEATING AND OROGRAPHIC LIFT. BUFKIT RUC SOUNDING INDICATING TT OF 50 AND K INDEX OF 35 WITH PW OF OVER AN INCH. DEVELOPMENT ALREADY TAKING PLACE WITH SCATTERED SHOWERS FROM NORTHERN MAINE TO CHAMBERLAIN LAKE. EXPECT ACTIVITY TO DIE DOWN AFTER SUNSET WITH THE LOSS OF SOLAR HEATING. LOW CLOUDS AND FOG TO DEVELOP OVER OUR CWA BEFORE MIDNIGHT AS SOUTHERLY LOW LEVEL MOIST FLOW COOLS. AREAS OF FOG AND STRATUS WILL LIFT DURING THE MORNING GIVING MOST AREAS SOME SUN BY LATE MORNING. COLD FRONT WILL ENTER NORTHWEST MAINE MID AFTERNOON AND THEN OFF THE COAST BEFORE MIDNIGHT. SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG A PRE FRONTAL TROUGH CROSSING THE NORTH EARLY IN THE AFTERNOON...ACROSS CENTRAL MAINE BY MID AFTERNOON AND THEN ACROSS SOUTHERN SECTIONS DURING THE LATE AFTERNOON. CAPE VALUES VERY LOW ACROSS THE NORTH BUT JUST OVER 1000 JOULES ACROSS THE SOUTHERN SECTIONS. HIGH PRESSURE WILL RIDGE ACROSS THE REGION SATURDAY NIGHT AND THEN MOVE NORTH OF THE STATE ON SUNDAY. WITH ZONAL FLOW ALOFT...FRONT WILL STALL OVER THE GULF OF MAINE AND CLOUDS MAY LINGER ACROSS SOUTHERN SECTIONS UNTIL MIDDAY SUNDAY. SHORTWAVE RIDGE WILL BUILD ACROSS THE STATE SUNDAY NIGHT INTO MONDAY WITH MOSTLY CLEAR SKIES. LONG TERM (MONDAY INTO FRIDAY): LEANED W/A CONSENSUS OF ETA/GFS & GEM FOR MONDAY INTO TUESDAY AS HIGH PRES BUILDS E INTO THE CANADIAN MARITIMES, EH. SOME CONCERN IS THERE FOR SOME DAMMING/WEDGING TO SET UP W/HIGH FCST TO BE ENE OF THE REGION. HINTED AT THIS IN GRIDS FOR MON W/MORE CLOUDS ACROSS NNE PORTION OF THE CWFA. FURTHER S...SHOULD BE ABLE TO GET AWAY W/PC CONDITIONS. TEMPS WILL BE TRICKY IF THIS SCENARIO PANS OUT. DID MAKE SOME ADJUSTMENTS TO MONDAY'S MAXES. NEXT FRONTAL BOUNDARY APPROACHES LATE TUESDAY INTO WEDNESDAY W/A ROUND OF SHOWERS. ATTM...DECIDED TO LEAVE ANY MENTION OF TSRA OUT GIVEN IT IS DAYS 4 & 5. STILL PLENTY OF TIME TO ASSESS THINGS. PLUS...IF DAMMMING/WEDGE DOES TAKE PLACE...THEN CONVECTION WILL BE LIMITED STABLE LLVLS. NOT BUYING INTO THE WAD OF QPF THAT THE GFS IS SHOWING GIVEN LACK OF SIGNIFICANT MOISUTRE TRANSPORT. FRONT IS FORECAST TO CLEAR THE COAST WED AFTERNOON WITH HIGH PRES BUILDING INTO THE REGION ON THURSDAY PROVIDING FOR DECENT WX. TEMPS ARE A REFLECTION OF THE MRF/MEX W/USUAL ADJUSTMENTS. MARINE: HAVE STAYED CLOSE TO ETA12 WINDS THROUGH 12Z MONDAY. FOR THE REMAINDER OF THE FORECAST HAVE MODIFIED GFS WINDS DOWN TO BETTER FIT LOWER STABLE LAYER. TEMPERATURE DEW POINT SPREAD AT 44027 STILL AROUND 6 DEGREES AND IS NOT CHANGING VERY MUCH. SUSPECT WE WILL HAVE TO WAIT UNTIL LATER THIS AFTERNOON FOR STRONGER SOUTHERLY FLOW BEFORE FOG DEVELOPS. LOOKING FOR FOG ACROSS THE WATERS TONIGHT THROUGH SATURDAY...THEN VISIBILITY IMPROVING EARLY SATURDAY NIGHT AS WINDS SHIFT INTO THE SOUTHWEST BRINGING IN DRIER AIR. HAVE INITIALIZED GRIDS WITH WNA WAVE WATCH III. HAVE LOWERED WAVE HEIGHTS 1 TO 2 FT BELOW WAVE MODEL NUMBERS TO BETTER FIT WINDS IN STABLE LAYER ACROSS OUR WATERS THROUGH SATURDAY. EXPECT MOST OF WAVES SATURDAY FROM SOUTH OF THE GULF OF MAINE WHERE WINDS ARE MIXING DOWN BETTER. AVIATION: VFR CONDITIONS WILL DETERIORATE TO MVFR CONDITIONS AT ALL TAF SITES THIS EVENING. CLEARING SKIES...WET GROUND & SLY FLOW WILL LEAD TO THE POTENTIAL FOR IFR CONDITIONS BOTH FOR CIGS/VSBYS AFT 07Z. .CAR...NONE. NEAR TERM/AVIATION: WOLFE SHORT TERM/MARINE: FOSTER LONG TERM/MARINE: HEWITT me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 925 PM EDT FRI MAY 14 2004 .DISCUSSION... .SHORT TERM... 00Z RAOBS/WV LOOP AND RUC ANALYSIS SHOW UPR TROF OVER CENTRAL NAMERICA BTWN RDGS ALG THE W COAST AND THE E COAST. SHRTWV RESPONSIBLE FOR THE RA EARLIER TDAY IS NOW LIFTING NE THRU WRN LK SUP. ALTHOUGH SFC LO/COLD FNT WELL TO THE ESE AND THE RA HAS ENDED WITH DEPARTURE OF DEEPER MSTR...ABUNDANT LLVL HI RH AS DEPICTED ON THE 00Z GRB SDNG BLO H85 RESULTING IN WDSPRD LO CLD IN THE SOMEWHAT CYC NLY FLOW OFF LK SUP OVER THE FA. SOME FOG/DZ LINGERING IN THE UPSLOPE AREAS OF THE NCNTRL. BREAKS NOTED OVER THE FAR W AND IN WRN LK SUP...BUT MORE SC NOTED IN THE MN ARROWHEAD/ ADJOINING PART OF ONTARIO ON THE CYC SIDE OF SHRTWV TRACK. MUCH DRIER LLVL AIR NOTED ON THE 00Z MPX SDNG...AND THIS DRIER LLVL AIR TENDING TO BREAK UP THE SC INTO NW WI ON THE ACYC SIDE OF H5 VORT TRACK. BACK EDGE OF SC APPEARS WITHIN AN HOUR OR TWO OR REACHING IWD PER STLT TRENDS. MAIN FCST CONCERNS TNGT CENTER ARND LO CLD TRENDS/IMPACT ON TMINS. 21Z RUC SHOWS SHRTWV OVER LK SUP TRACKING NE TO NEAR JAMES BAY BY 09Z. A SFC HI PRES RDG PROGGED TO REACH NW WI BY 09Z...WITH WEAKENING AND MORE ACYC NW FLOW DVLPG OVER THE FA OVERNIGHT. SINCE THE FA IS ON THE ACYC SIDE OF THE TRACK OF THIS FEATURE...EXPECT THE BULK OF THE SC IN NE MN/ADJOINING ONTARIO TO REMAIN TO THE NW WITH DRYING TREND NOTED UPSTREAM IN NW WI CONTINUING INTO THE FA OVERNIGHT. ALTHOUGH LOSS OF SOLAR INSOLATION WL CANCEL MIXING PROCESS...LLVL AIRMASS SHOWN ON MPX SDNG IS SO DRY (AS IS THE AIR BELOW SC LEVEL ON THE INL SDNG AS WELL) THAT TRAJECTORIES FM THIS AREA SHOULD EVAPORATE THE LOW CLD. RUC SHOWS THE MOST PERSISTENT SFC-H85 MSTR LINGERING OVER THE NRN KEWEENAW/ERN ZNS THRU 09Z...SO CLRG WL NOT REACH THESE AREAS TIL LATE. LOWEST MIN TEMPS WL BE OVER THE INTERIOR W...WHERE SKIES WL CLEAR EARLIST AND WINDS WL GO NR CALM LATER TNGT WITH APRCH OF SFC RDG. SFC DWPTS NR 25 UPSTREAM LOOK LIKE A RSNBL ESTIMATE FOR TMIN IN THESE AREAS. GOING FCST APPEARS TO HAVE A GOOD HANDLE ON EXPECTED TRENDS... SO ONLY MINOR CHGS NECESSARY. KC .LONG TERM... COOL/PLEASANT DAY ON TAP SAT AS HIGH PRES DRIFTS E ACROSS UPPER MI. SHOULD BE A DECENT DISPLAY OF SUNSHINE...THOUGH WITH 850MB THERMAL TROF OVER THE AREA...WILL LIKELY SEE SCT TO MAYBE BKN CU DEVELOP FOR A TIME LATE MORNING/EARLY AFTN...ESPECIALLY INTERIOR E HALF. GOING FCST OF GENERALLY MID 50S AWAY FROM LAKE SUPERIOR LOOKS FINE AND AGREES WELL WITH UPSTREAM TEMPS TODAY AND WITH LATEST ROUND OF MOS GUIDANCE. HIGH SLIPS E AND RETURN FLOW/WAA DEVELOPS ACROSS THE ENTIRE AREA SAT NIGHT AS SHORTWAVE TRACKS ACROSS ND TO WRN ONTARIO. ASSOCIATED SFC FRONT REACHES FAR NE MN 12Z SUN. ISENTROPIC ASCENT IS FAIRLY STRONG DURING THE NIGHT (295K SFC)...BUT INITIAL MOISTURE RETURN IS LIMITED AND NO ELEVATED INSTABILITY IS PRESENT IN FCST SOUNDINGS...SO HAVE NOT INCLUDED ANY PCPN MENTION ATTM. LATER SHIFTS WILL NEED TO WATCH THIS TIME FRAME FOR POTENTIAL PCPN INCLUSION. FOR NOW...JUST EXPECT AN INCREASE IN CLOUD COVER IN WAA REGIME. FRONTAL BNDRY WILL ONLY DRIFT INTO WRN UPPER MI SUN AS ADDITIONAL SHORTWAVE ENERGY HEADS THRU THE DAKOTAS TOWARD UPPER MISSISSIPPI VALLEY. ETA SHOWS MLCAPE INCREASING TO A FEW HUNDRED J/KG OVER THE W WITH LITTLE/NO CIN...BUT ITS BNDRY LAYER MOISTURE PROFILE LOOKS A BIT TOO MOIST. NONETHELESS...WITH FRONTAL BNDRY IN THE AREA AND ETA/GFS HINTING AT SOME PCPN...WILL LEAVE GOING FCST OF CHC POPS OVER ABOUT THE W HALF OF FCST AREA FOR SUN AFTN. SUN NIGHT/MON...PCPN CHANCES INCREASE SUBSTANTIALLY AS WEAK SFC WAVE IS INDUCED ALONG FRONTAL BNDRY BY APPROACHING SHORTWAVE. SIGNIFICANT UPPER LEVEL DIVERGENCE DEVELOPS OVER WRN GREAT LAKES UNDER RIGHT ENTRANCE OF JET DEVELOPING OVER ONTARIO. LOW-LEVEL JET RESPONDS... INCREASING TO 50KTS INTO SRN WI WITH 850MB DWPTS RISING TO 6-8C INTO UPPER MI. CONVERGENCE ALONG 850MB WARM FRONT LIFTING INTO SRN UPPER MI WILL FURTHER AID PCPN DEVELOPMENT. HAVE THUS RAISED POPS TO LIKELY FROM SW TO NE ACROSS FCST AREA SUN NIGHT INTO MON MORNING WITH DIMINISHING TREND FROM W TO E MON AFTN. TUE THRU FRI...GFS/CANADIAN/UKMET/ECMWF ARE IN VERY GOOD AGREEMENT FOR THIS TIME FRAME. AT THE BEGINNING OF THE PERIOD...ALL THE MODELS SHOW HIGH PRES BUILDING OVER THE GREAT LAKES TUE IN THE WAKE OF MONDAYS RAIN EVENT. WITH GOOD AGREEMENT TIMING-WISE...NEXT SYSTEM OF CONCERN ARRIVES LATER WED/THU. MAIN DIFFERENCE NOTED IS THAT 00Z/06Z GFS ARE STRONGER WITH THE NRN STREAM DIGGING INTO UPPER LAKES/NEW ENGLAND. PER GFS ENSEMBLE MEAN/HPC GUIDANCE...WILL NOT GO WITH AS MUCH COOLING BEHIND SYSTEM THU/FRI. LOOKS LIKE A FAIRLY DRY WRLY FLOW WILL BE PREVALENT PRIOR TO SYSTEM ARRIVING WED NIGHT/THU...SO WILL CONTINUE TO HOLD OFF ON SHRA CHC UNTIL WED NIGHT. FAIRLY PROGRESSIVE FLOW SHOULD KEEP WINDOW OF SHRA OPPORTUNITY SHORT WITH FRONT LIKELY THRU THE AREA EARLY THU...THEN DRY THU NIGHT/FRI. TEMPS SHOULD BE CLOSE TO NORMALS THRU THE PERIOD WITH WED THE WARMEST DAY. ROLFSON && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 410 PM EDT FRI MAY 14 2004 .DISCUSSION... WATER VAPOR IMAGERY/RUC ANALYSIS SHOW MIDLEVEL TROF FROM CENTRAL CANADA S INTO THE PLAINS STATES. SEVERAL SHORTWAVES WERE LIFTING OUT OF THE TROF WITH THE ONE OVER MN BEING THE MOST IMPORTANT FOR THIS AREA. AS HAD BEEN EXPECTED...A SOLID SHIELD OF RAIN SPREAD ACROSS MOST OF UPPER MI TODAY WITH TEMPS UNSEASONABLY COOL IN THE UPPER 30S TO MID 40S. HIGH TEMP OF 40 JUST AFTER MIDNIGHT HERE AT THE OFFICE TIES RECORD LOW MAX TEMP FOR THE DAY (ETA HAD A GREAT HANDLE ON TEMPS TODAY AS FAR BACK AS MODEL RUN 12Z WED). BACK EDGE OF RAIN HAS PROGRESSED TO THE ERN U.P. WITH SOME SPRINKLES/DZ LINGERING FROM THE KEWEENAW TO NCNTRL AREAS IN MOIST UPSLOPE FLOW. NO SIGNIFICANT MODEL DIFFERENCES NOTED TODAY THAT WILL REALLY AFFECT SENSIBLE WX IN THE SHORT TERM. BASED ON LINEAR EXTRAPOLATION...-RA SHOULD BE OUT OF ERN COUNTIES BY START OF TONIGHT PERIOD (22Z)...BUT WILL CARRY SOME SPRINKLES/-DZ EARLY THIS EVENING KEWEENAW/NCNTRL EWD DUE TO MOIST UPSLOPE FLOW EARLY. SFC HIGH THEN SETTLES OVER WI/WRN UPPER MI BY 12Z SAT. QUITE A BIT OF STRATOCU LINGERS OVER NRN MN JUST AHEAD OF SFC RIDGE AXIS...BUT IT IS BECOMING MORE CELLULAR AND IS MIXING OUT A BIT. HOWEVER...SINCE DAYTIME HEATING WILL NOT BE ABLE TO MIX MOST OF IT OUT BEFORE SUNSET...BELIEVE IT MAY TAKE A WHILE FOR CLOUDS TO CLEAR OUT OF FCST AREA TONIGHT. WILL TREND SKY TO MOSTLY CLEAR OVER WRN AREAS AROUND MIDNIGHT...AND BRING A DECREASING CLOUD TREND TO ERN AREAS LATE. ETA/GFS MOS TEMPS LOOK PRETTY GOOD OVER THE W WHERE SKIES CLEAR (TEMPS BLO FREEZING INTERIOR). FROST/FREEZE HEADLINES ARE NOT BEING ISSUED YET (BEGINS MAY 22ND). COOL/PLEASANT DAY ON TAP SAT AS HIGH PRES DRIFTS E ACROSS UPPER MI. SHOULD BE A DECENT DISPLAY OF SUNSHINE...THOUGH WITH 850MB THERMAL TROF OVER THE AREA...WILL LIKELY SEE SCT TO MAYBE BKN CU DEVELOP FOR A TIME LATE MORNING/EARLY AFTN...ESPECIALLY INTERIOR E HALF. GOING FCST OF GENERALLY MID 50S AWAY FROM LAKE SUPERIOR LOOKS FINE AND AGREES WELL WITH UPSTREAM TEMPS TODAY AND WITH LATEST ROUND OF MOS GUIDANCE. HIGH SLIPS E AND RETURN FLOW/WAA DEVELOPS ACROSS THE ENTIRE AREA SAT NIGHT AS SHORTWAVE TRACKS ACROSS ND TO WRN ONTARIO. ASSOCIATED SFC FRONT REACHES FAR NE MN 12Z SUN. ISENTROPIC ASCENT IS FAIRLY STRONG DURING THE NIGHT (295K SFC)...BUT INITIAL MOISTURE RETURN IS LIMITED AND NO ELEVATED INSTABILITY IS PRESENT IN FCST SOUNDINGS...SO HAVE NOT INCLUDED ANY PCPN MENTION ATTM. LATER SHIFTS WILL NEED TO WATCH THIS TIME FRAME FOR POTENTIAL PCPN INCLUSION. FOR NOW...JUST EXPECT AN INCREASE IN CLOUD COVER IN WAA REGIME. FRONTAL BNDRY WILL ONLY DRIFT INTO WRN UPPER MI SUN AS ADDITIONAL SHORTWAVE ENERGY HEADS THRU THE DAKOTAS TOWARD UPPER MISSISSIPPI VALLEY. ETA SHOWS MLCAPE INCREASING TO A FEW HUNDRED J/KG OVER THE W WITH LITTLE/NO CIN...BUT ITS BNDRY LAYER MOISTURE PROFILE LOOKS A BIT TOO MOIST. NONETHELESS...WITH FRONTAL BNDRY IN THE AREA AND ETA/GFS HINTING AT SOME PCPN...WILL LEAVE GOING FCST OF CHC POPS OVER ABOUT THE W HALF OF FCST AREA FOR SUN AFTN. SUN NIGHT/MON...PCPN CHANCES INCREASE SUBSTANTIALLY AS WEAK SFC WAVE IS INDUCED ALONG FRONTAL BNDRY BY APPROACHING SHORTWAVE. SIGNIFICANT UPPER LEVEL DIVERGENCE DEVELOPS OVER WRN GREAT LAKES UNDER RIGHT ENTRANCE OF JET DEVELOPING OVER ONTARIO. LOW-LEVEL JET RESPONDS... INCREASING TO 50KTS INTO SRN WI WITH 850MB DWPTS RISING TO 6-8C INTO UPPER MI. CONVERGENCE ALONG 850MB WARM FRONT LIFTING INTO SRN UPPER MI WILL FURTHER AID PCPN DEVELOPMENT. HAVE THUS RAISED POPS TO LIKELY FROM SW TO NE ACROSS FCST AREA SUN NIGHT INTO MON MORNING WITH DIMINISHING TREND FROM W TO E MON AFTN. TUE THRU FRI...GFS/CANADIAN/UKMET/ECMWF ARE IN VERY GOOD AGREEMENT FOR THIS TIME FRAME. AT THE BEGINNING OF THE PERIOD...ALL THE MODELS SHOW HIGH PRES BUILDING OVER THE GREAT LAKES TUE IN THE WAKE OF MONDAYS RAIN EVENT. WITH GOOD AGREEMENT TIMING-WISE...NEXT SYSTEM OF CONCERN ARRIVES LATER WED/THU. MAIN DIFFERENCE NOTED IS THAT 00Z/06Z GFS ARE STRONGER WITH THE NRN STREAM DIGGING INTO UPPER LAKES/NEW ENGLAND. PER GFS ENSEMBLE MEAN/HPC GUIDANCE...WILL NOT GO WITH AS MUCH COOLING BEHIND SYSTEM THU/FRI. LOOKS LIKE A FAIRLY DRY WRLY FLOW WILL BE PREVALENT PRIOR TO SYSTEM ARRIVING WED NIGHT/THU...SO WILL CONTINUE TO HOLD OFF ON SHRA CHC UNTIL WED NIGHT. FAIRLY PROGRESSIVE FLOW SHOULD KEEP WINDOW OF SHRA OPPORTUNITY SHORT WITH FRONT LIKELY THRU THE AREA EARLY THU...THEN DRY THU NIGHT/FRI. TEMPS SHOULD BE CLOSE TO NORMALS THRU THE PERIOD WITH WED THE WARMEST DAY. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1100 AM EDT FRI MAY 14 2004 .DISCUSSION... MAIN FCST CONCERNS THIS AFTERNOON ARE PCPN TRENDS AND TEMPS. WV IMAGERY AND RUC ANALYSIS INDICATED A MID LVL TROF FROM CNTRL CANADA THROUGH THE DAKOTAS TO THE SRN PLAINS AND A RDG OVER ERN NOAM LEAVING SW FLOW THROUGH THE WRN LAKES. ONE UPSTREAM SHRTWV WAS LOCATED OVER THE ERN DAKOTAS WHILE ANOTHER TO THE SOUTH WAS MOVING INTO NRN IL. AT THE SFC...A TROF EXTENDED FROM ERN ONTARIO AND NRN LK HURON TO ERN IL. AREA RADARS INDICATED A BROAD AREA OF -RA OVER THE ERN 2/3 OF WI AND MOST OF UPR MI SUPPORTED BY DEEP LYR QVECTOR CONV AND UPR LVL DIV WITH RIGHT ENTRANC OF H25 JET FROM WRN WI INTO NRN ONTARIO. IR LOOP INDICATED EXPANSION OF COLDER CLOUD TOPS OVER THE AREA. RADAR TRENDS AND 12Z RUC SUGGEST STEADY -RA WILL LINGER THROUGH 21Z OVER THE ERN 2/3 OF UPR MI WITH A DIMINISHING TREND OVER THE WEST DURING THE AFTERNOON. THE ETA IS SLIGHTLY FASTER WITH MOVING THE PCPN EAST. WITH CONTINUED SUPPORT FROM UPSTREAM SHRTWV...HAVE LEANED MORE TOWARD THE SLOWER RUC...EVEN THOUGH PCPN MAY TAPER OFF A BIT BTWN 18Z-21Z CNTRL. THE WEST SHOULD STILL SEE AT LEAST INTERMITTENT -RA THROUGH EARLY TO MID AFTERNOON. EXPECT PCPN TO QUICKLY TAPER OFF LATE THIS AFTERNOON AND EVENING FROM WEST TO EAST AS DYNAMICS AND DEEPER MOISTURE DEPART. PCPN AND THICK CLOUDS WILL KEEP TEMPS FROM CLIMBING MUCH THIS AFTERNOON WITH MAX READINGS ONLY A FEW DEGREES AT MOST ABV CURRENT READINGS FROM 37 TO 43 FROM NW TO SE. EVEN OVER THE WEST...WHERE PCPN MAY DIMINISH EARLIER...CAA WILL ALSO SUPPRESS ANY WARMUP. TEMPS LOWERED SLIGHTLY BUT GOING FCST WAS GENERALLY ON TRACK. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 1008 AM EDT FRI MAY 14 2004 .SHORT TERM...TODAY'S 12Z SOUNDING A LITTLE DRIER THAN YESTERDAY'S. HOWEVER...IN LOOKING AT VARIOUS PARAMETERS...THE TOTAL-TOTALS AND SWEAT INDEX IS HIGHER AND WET-BULB ZERO HEIGHTS ARE QUITE A BIT LOWER. MODIFIED LI'S AND CAPE VALUES ALSO SUGGEST POTENTIAL FOR ISOLATED SEABREEZE CONVECTION. LATEST RUC SHOWING SOME ISOLATED SHWRS/TSTMS TO DEVELOP AROUND MIDDAY ON SEABREEZE. AS A RESULT...HAVE DECIDED TO ADD A SLGT CHC OF PRECIP INLAND FOR THE BALANCE OF THE DAYLIGHT HOURS. NO OTHER CHANGES TO CURRENT SHORT-TERM GRIDS. && .MARINE...SFC HIGH CENTERED PRETTY MUCH OVERHEAD THIS MORNING WITH LOCALIZED SEABREEZES DRIVING THE WIND FIELDS TODAY. SEAS REMAIN LIGHT WITH NO SIGNIFICANT CHANGES ANTICIPATED TO MARINE. && .AVIATION...CLEAR EARLY MORNING HOURS GIVING WAY TO SEABREEZE CUMULUS. THIS SHOULD BE THE CASE THROUGH THE AFTERNOON WITH AN ISOLATED SHOWER OR TSTM PSBL. && .PRELIMINARY POINT TEMPS/POPS... MHX 82 64 82 64 / 10 10 10 10 EWN 86 63 86 63 / 20 10 10 10 HSE 80 68 80 68 / 10 10 10 10 PGV 86 68 86 67 / 20 10 10 10 && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. && $$ 11/COLLINS nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1000 AM EDT FRI MAY 14 2004 .PUBLIC...WX ELEMENTS IN THE ZFP LOOKS TO HAVE THE DAY/S CONDS HANDLED QUITE WELL. MORNING AND FCST SOUNDINGS MAINTAIN DECENT CAP WITH MODERATE CIN OVER THE AREA ALONG WITH NO DEFINITIVE FOCUS AREAS OF LIFT...INSTABILITY...NOR MOISTURE THOUGH PWATS HAVE INCRD TO AROUND THE 1.00 INCH AREA. RUC AND WSETA DO MAINTAIN ISOLD AREAS OF SEABREEZE CONVECTION BUT NOT ENOUGH WHERE IT WOULD WARRANT A CHANGE IN THE ZFP. IF IT OCCURS...COULD MOST LIKELY BE HANDLED WITH NOWCASTS. CLOUD STREAKS HAVE ALREADY BEGUN TO FORM ON VIS PIX MAINLY INLAND FROM ALL COASTAL COUNTIES SO PCLDY FOR ALL AREAS LOOKS GOOD. ONLY CHANGE WILL BE TO REWORD COASTAL SC COUNTIES WITH PCLDY INSTEAD OF MOSUNNY WITH ANTICIPATION OF MORE CU TO DEVELOP...BUT ALL OTHER ELEMENTS LOOK GOOD. && .MARINE...SE TO S FLOW OVER THE WATERS WILL CONTINUE THIS AFTERNOON. SEAS 2 TO 3 FT CLOSE TO SHORE AND AND 3 TO 5 FT IN THE GEORGIA WATERS OUTSIDE OF 20 NM. OVERALL...NO CHANGES TO THE FORECAST THIS AFTN. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. && $$ 24/8 sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 1000 AM CDT FRI MAY 14 2004 .SHORT TERM...CLD TOP TEMPS ASSOCIATED WITH THE CONV LOCATED JUST SOUTH OF THE RIO GRANDE HAS BEEN STEADILY WARMING AND THE KBRO BASE REFLECTIVITY SHOWS THE CONV MOVING SLOWLY SE. THE 12Z BRO SOUNDING SHOWS A FAIRLY MOIST AND UNSTABLE AIRMASS IN PLACE WITH A PWAT OF AROUND 1.8 INCHES AND AN LI OF -6.3. HOWEVER...CONV FROM EARLIER THIS MORNING HAS LIKELY STABILIZED THE ATMS SOMEWHAT WHICH IS INHIBITING ANY ADDITIONAL SIGNIFICANT CONV FORMATION ATTM. IN ADDITION...PLENTY OF DEBRIS CLD COVER IS IN PLACE OVER THE BRO CWA WHICH WILL ALSO DELAY THE DAYTIME HEATING AND THE ASSOCIATED DESTABILIZATION. BOTH THE RUC AND MESO-ETA 5H FIELDS INDICATE THAT THE 5H SHORT WAVE AXIS IS ROUGHLY PARALLEL TO THE TX COASTLINE THIS MORNING. THIS POSITIONING WILL MAINTAIN CONV CHCS ALONG THE IMMEDIATE COASTLINE FOR TODAY AND WILL REALIGN THE POPS AND QPF ACCORDINGLY. WITH THE DEBRIS CLD COVER REDUCING THE AFTERNOON HEATING...THIS WILL LIKELY HOLD DOWN TEMPS TO NEAR OR BELOW GUIDANCE. NO OTHER CHANGES NEEDED IN THE CURRENT ZFP. && .MARINE...BUOY020 CURRENTLY REPORTS A NE WIND AT 17G23KT WITH 8 FT SWELLS. CLOSER TO SHORE...MTRPIL REPORTS A LIGHT NORTHERLY. WILL MAINTAIN THE SCA FOR THE OFFSHORE WATERS...BUT WILL LOWER IT ALONG THE LAGUNA MADRE. && .AVIATION...GENERALLY EXPECT VFR CONDITIONS TO CONTINUE IN THE CURRENT TAF PERIOD AS MID AND UPPER LEVEL CLD COVER DOMINATES. CURRENT TAF PACKAGE LOOKS OK. && .BRO WATCHES/WARNINGS/ADVISORIES...SCA FOR GMZ150-155-170-175. && $$ SYNOPTIC/GRIDS/AVIATION/MARINE...60 MESO...CAMPBELL/VEGA tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1014 AM EDT FRI MAY 14 2004 .UPDATE...NO CHANGE ANTICIPATED TO GOING FORECAST AT THIS TIME... ALTHOUGH ISOLATED POPS MAY NEED TO BE ADDED SOON FOR PART OF THE AREA. MORNING UA SOUNDINGS...AND RUC MODEL SOUNDINGS...SUGGEST AN AIRMASS SIMILAR TO YDA...WITH VERY LITTLE CAP...AND MUCAPE 1500 TO 2000. LIKE YDA...THINK MIXING THE BL WILL LOWER THESE CAPES SOMEWHAT. ALSO...HAVING A HARD TIME PICKING OUT ANY AREAS OF CONVERGENCE...OR FOCUS...FOR ANY CONVECTION. FOR THIS REASON...PLAN TO LEAVE ISOLD POPS OUT FOR NOW...BUT MY NEED TO ADD TO SOME ZONES...FOR EXAMPLE ALONG THE COAST...SHOULD ANY CONVERGENCE ZONES BEGIN TO SET UP. WILL MONITOR SATELLITE AND SURFACE OBS FOR INDICATIONS OF CONVERGENCE AREAS OR BOUNDARIES BEGINNING TO SET UP. ANY SHOWERS OR STORMS THAT DO DEVELOP SHOULD NOT APPROACH SEVERE LEVELS...AS WIND SHEAR EXTREMELY WEAK...AND CAPE ONLY MODEST. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. VA...NONE. NC...NONE. && $$ REILLY va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1025 AM CDT FRI MAY 14 2004 .UPDATE... LATEST RADAR DATA INDICATED RAIN CONTINUING TO MOVE OUT OF THE FORECAST AREA AS WAVE ON SURFACE FRONT LIFTS NORTHEASTWARD INTO LOWER MICHIGAN. VISIBLE SATELLITE IMAGERY SHOWED CLEARING SKIES ADVANCING TOWARD SOUTHEAST MN AND NORTHEAST IOWA. HOWEVER...LOW LEVEL CLOUDS IN NORTHERLY FLOW BEHIND THE FRONT FILLING IN. OVERALL TREND OF DECREASING CLOUDS AS IN CURRENT FORECAST STILL APPEARS ON TRACK FOR THE AFTERNOON INTO EARLY EVENING...EXCEPT FOR CENTRAL WI...AS INDICATED BY LATEST RUC RELATIVE HUMIDITY PARAMETERS. PLAN TO SEND UPDATED ZONES AROUND 1045 AM WITH ANTICIPATION OF DRY FORECAST FOR THIS AFTERNOON. CHILLY TEMPERATURES FOR THIS TIME OF YEAR...WITH VALUES IN CURRENT FORECAST ON TRACK. && THOMPSON .SHORT TERM...TODAY THROUGH SUNDAY NIGHT FORECAST CONCERNS ARE ON PRECIPITATION TRENDS THIS MORNING...THE FOG AND TEMPERATURES TONIGHT WITH FROST POSSIBILITIES...THEN PRECIPITATION CHANCES LATER IN THE WEEKEND. 08Z SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY EXTENDING FROM NORTHERN LOWER MICHIGAN...THROUGH CHICAGO AND DOWN INTO SOUTH CENTRAL MISSOURI. AREA RADARS SHOWING SHOWERS FALLING TO THE NORTH OF THE FRONT IN VICINITY OF THE 850MB FRONT...ALTHOUGH BAND OF SHOWERS FALLING ACROSS NORTH CENTRAL IOWA AND SOUTHERN MINNESOTA ONLY PRODUCING A TRACE TO ONE HUNDRETH. 00Z 14MAY04 MODELS SHOWED NO MAJOR INITIALIZATION ERRORS AND WERE IN GOOD AGREEMENT THROUGH 48 HOURS. AFTER THAT...GFS STRONGER WITH 500 MB LOW COMING ONTO THE WEST COAST. UKMET SUPPORTS THE GFS SOLUTION SO WILL LEAN TOWARDS THIS IN THE LATER PERIODS. WEAK LIFT ACROSS THE AREA THIS MORNING WILL SLIDE EAST. MODELS PROG DRIER AIR TO ADVECT IN LATER TODAY...ALTHOUGH MAY HOLD ON TO A BROKEN CUMULUS DECK MUCH OF THE DAY...ESPECIALLY EAST OF THE MISSISSIPPI RIVER. HIGH PRESSURE THEN BUILDS ACROSS THE GREAT LAKES TONIGHT AND PUSHES EAST OF THE AREA LATER SATURDAY. GOOD RADIATIONAL COOLING EXPECTED TONIGHT AND WITH ALL THE LOWER LEVEL MOISTURE WILL LIKELY SEE SOME AREAS OF FOG LATE. IN ADDITION...TEMPERATURES TO DROP OFF INTO THE LOWER TO MIDDLE 30S MOST LOCATIONS. WITH THAT IN MIND WILL ALSO MENTION SCATTERED FROST...BUT WILL HOLD OFF ON ANY HEADLINES. QUIET WEATHER TO CONTINUE THROUGH SATURDAY. ON SUNDAY...LOW PRESSURE TAKES SHAPE ON THE LEESIDE OF THE COLORADO ROCKIES. A WARM FRONT WILL EXTEND EAST FROM THE LOW ACROSS CENTRAL NEB AND INTO SOUTHERN MINNESOTA. BOTH GFS AND ETA HINTING CONTINUE TO SHOW CONVECTION NORTH OF THE FRONT ACROSS EASTERN SOUTH DAKOTA INTO SOUTHERN MINNESOTA. POP/WEATHER GRIDS HAVE A GOOD HANDLE ON THIS. ALTHOUGH WITH CONSISTENCY OF MODELS HAVE UPPED THE POPS FOR SUNDAY AFTERNOON. .LONG TERM...MONDAY THROUGH THURSDAY GFS CONSISTENT WITH LIFTING WARM FRONT ACROSS THE FORECAST AREA SUNDAY NIGHT FOLLOWED BY THE COLD FRONT ON MONDAY. LOOKS AS THOUGH A RATHER UNSETTLED PERIOD IS SETTING UP FOR LATE THIS WEEKEND INTO EARLY NEXT WEEK. CURRENT EXTENDED GRIDS HAVE THIS WELL IN HAND AND THUS WILL MAKE NO CHANGES. && .ARX...WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. WI...NONE. && $$ RABERDING wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 341 AM EDT SAT MAY 15 2004 .DISCUSSION... HIGH PRESSURE OVER THE UPPER MIDWEST IS SLOWLY BUILDING INTO THE REGION...WITH COLD AIR ADVECTION UNDERWAY ACROSS SE MICHIGAN IN THE WAKE OF THE SURFACE COLD FRONT. AREA RADAR DATA INDICATES ALL PRECIP NOW EAST OF THE FORECAST AREA. THIS HIGH PRESSURE WILL SETTLE INTO THE GREAT LAKES REGION THIS WEEKEND...BRINGING COOLER AND DRYER CONDITIONS TO SE MICHIGAN. THIS WILL BE THE FIRST DAY IN OVER A WEEK THAT CONVECTION HAS NOT DEVELOPED SOMEWHERE OVER SE MICHIGAN. OVERALL...THE 00Z MODEL SUITE ARE IN RATHER GOOD AGREEMENT WITH THE LARGE SCALE PATTERN AND ARE REASONABLY CONSISTENT WITH PREVIOUS MODEL RUNS. THUS VERY LITTLE UPDATES WILL BE NEEDED TO THE ONGOING FORECAST. THE STRONG UPPER RIDGE OVER THE EAST COAST WILL BREAK DOWN TODAY...ALLOWING THE FLOW ALOFT TO BECOME MORE ZONAL ACROSS THE CONUS BY THE END OF THE WEEKEND. SURFACE HIGH PRESSURE WILL MOVE INTO THE STATE TODAY...THEN PUSH EAST INTO THE EASTERN GREAT LAKES BY SUNDAY. NUMEROUS SHORT WAVES WILL MOVE ACROSS THE UPPER MIDWEST SUNDAY INTO MONDAY...WITH RETURN FLOW SETTING UP ACROSS THE SOUTHERN LAKES REGION ON THE BACK SIDE OF THE SURFACE HIGH. A COLD FRONT WILL SLOWLY ADVANCE SOUTH ACROSS THE STATE MONDAY NIGHT INTO TUESDAY...BRINGING THE NEXT SIGNIFICANT CHANCE OF SHOWERS/THUNDERSTORMS. TODAY WILL START OFF QUITE CLOUDY. STRATUS WITH BASES AT OR BELOW 1500 FT CURRENTLY COVERS MOST OF LOWER MICHIGAN. ETA AND RUC SOUNDINGS SHOW THIS MOISTURE TRAPPED BELOW A 950MB INVERSION. EXPECT THAT THESE CLOUDS WILL PERSIST INTO THE AFTERNOON BEFORE DIURNAL WARMING AND INCREASING SURFACE ANTICYCLONIC FLOW HELP MIX THEM OUT. MEANWHILE...IR SATELLITE LOOP SHOWS AN EXTENSIVE AREA OF CIRRUS STREAMING NORTHWARD ACROSS ILLINOIS. THESE CLOUDS HAVE SOME UPPER JET SUPPORT...WHICH DOES NOT PUSH EAST OF THE AREA UNTIL LATE THIS AFTERNOON. SO EXPECT A CLOUDY START TO THE DAY WITH A GRADUAL DECREASE IN CLOUD COVER MID TO LATE AFTERNOON. GUIDANCE TEMPS LOOK REASONABLE BASED ON UPSTREAM TEMPS FROM YESTERDAY AND GIVEN THE CLOUD COVER THROUGH THE FIRST HALF OF THE DAY. CLOUDS SHOULD CLEAR OUT BY EVENING. THE BOUNDARY LAYER WILL DECOUPLE AS SURFACE HIGH PRESSURE WILL BE OVERHEAD. DESPITE VERY GOOD LOW LEVEL DRY AIR ADVECTION INTO THE REGION TODAY...THINK THE DEWPOINTS TONIGHT OFFERED BY THE MODELS MAY BE A BIT TOO LOW GIVEN THE AMOUNT OF RAINFALL THE PAST WEEK AND MOIST SOIL CONDITIONS. THEREFORE WILL NOT GO AS LOW AS GUIDANCE TEMPS TONIGHT AND RETAIN THE MENTION OF FOG. THE DAY SHIFT WILL HAVE TO MONITOR DEWPOINT TRENDS ON THE CONDITION THAT IF THEY DO DROP TO WHAT GUIDANCE SUGGESTS...FROST MAY BE POSSIBLE TONIGHT ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA. RETURN FLOW AROUND THE SURFACE HIGH WILL DEVELOP OVER THE REGION ON SUNDAY. THE STRONGEST WARM AIR ADVECTION WILL ACTUALLY OCCUR ACROSS THE UPPER MIDWEST. A 50+ LOW LEVEL JET WILL DEVELOP OVER THE PLAINS SUNDAY NIGHT...SENDING COPIOUS AMOUNTS OF MOISTURE INTO THE UPPER MISSISSIPPI VALLEY/UPPER GREAT LAKES REGION. THIS MOISTURE COMBINED WITH A MID LEVEL SHORT WAVE AND UPPER LEVEL JET TO ALLOW QUITE A BIT OF NOCTURNAL CONVECTION. THIS CONVECTION IS EXPECTED TO REMAIN NORTHWEST OF THE FORECAST AREA SUNDAY NIGHT. A COLD FRONT AND ANY OUTFLOW BOUNDARIES WILL SINK SOUTH INTO NORTHERN LOWER MICHIGAN ON MONDAY...THEN CONTINUE SOUTH INTO SOUTHERN LOWER MICHIGAN BY MONDAY NIGHT. A LOW LEVEL JET IS STILL EXPECTED TO DEVELOP MONDAY NIGHT...WITH MAXIMUM CONVERGENCE FOCUSSED JUST WEST OF THE REGION. THE CURRENT ETA SOLUTIONS SHOWS A WELL DEFINED INSTABILITY AXIS ALONG THE FRONT INTO SE LOWER MICHIGAN...SO THERE IS A GOOD POTENTIAL FOR SOME FORWARD PROPAGATION OF UPSTREAM CONVECTION. THUS CHANCE POPS STILL LOOKS WARRANTED MONDAY NIGHT RIGHT INTO THE DAY TUESDAY BEFORE THE FRONT SLIDES SOUTH OF THE STATE. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ CONSIDINE EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 230 AM EDT SAT MAY 15 2004 .DISCUSSION... TODAY/TONIGHT: PRECIP CHANCES NOT LOOKING GREAT TODAY... ESPECIALLY OUTSIDE OF THE NORTHWEST PIEDMONT. AIRMASS BECOMES MODERATELY UNSTABLE TODAY ACCORDING TO THE ETA FORECAST SOUNDINGS... ALTHOUGH A COMPARISON TO THE 00Z GSO SOUNDING SHOWS THAT THE ETA INITIALIZED THE THERMAL PROFILE RATHER POORLY. UPPER AIR ANALYSES & TRAJECTORIES INDICATE A 1-2 DEGREE COOLING AT 850 MB AND WARMING AT 700 MB TODAY... & THE RUC PICKS UP ON THIS EXPECTED CAP WHEREAS THE ETA DOES NOT. UPPER DIFFLUENT FLOW IS PRESENT BUT THE FLOW IS SO WEAK THE DIVERGENCE IS NEARLY NEGLIGIBLE. WILL KEEP LOW CHANCE POPS FROM ROXBORO TO ALBEMARLE NORTHWEST TODAY INTO THE EVENING. AN ISOLATED SEA BREEZE SHOWER IS NOT OUT OF THE QUESTION BUT THE SCANT COVERAGE EXPECTED IS NOT WORTH MENTIONING IN THE FORECAST TEXT. WILL FOLLOW PERSISTENCE OF 80-85/60-65 FOR HIGH TODAY & LOW TONIGHT. SUN THROUGH MON: SURFACE FRONT APPROACHES FROM THE NW. UPPER DIVERGENCE BECOMES A BIT MORE PROFOUND SUNDAY IN THE RIGHT JET ENTRANCE REGION. WILL RETAIN THE CHANCE POPS AS THE FRONT GETS CLOSER TO THE CWA... WITH THE BETTER COVERAGE NORTH AND WEST SECTIONS. MOISTURE GRADUALLY DEEPENS SUNDAY... WHICH SHOULD ALLOW FOR SCATTERED COVERAGE DESPITE THE WEAKENING LOW-MID LEVEL FLOW WHICH MAY LIMIT UPDRAFT/DOWNDRAFT LIFETIMES. THE FRONT STARTS TO WASH OUT JUST TO OUR NORTH ON MONDAY BUT LINGERING LOW LEVEL POOLING OF MOISTURE OVER NC SHOULD STILL ALLOW WIDELY SCATTERED CONVECTION TO BUILD IN THE AFTERNOON. TUE THROUGH FRI: RIDGE OFF SOUTHEAST COAST FINALLY GIVES WAY A BIT AS UPPER FLOW BECOMES MORE ZONAL & SPEEDS UP ACROSS THE NORTHERN STATES. MID LEVEL HEIGHTS OVER NC FALL SLIGHTLY... 850 MB FLOW SPEEDS UP AND BECOMES MORE WSW... AND A LEE TROUGH DEVELOPS IN THE BOUNDARY LAYER. GFS SHOWS THE NEXT FRONT BECOMING EAST-WEST ORIENTED ACROSS THE OHIO VALLEY TO MID ATLANTIC COAST... FAR ENOUGH TO OUR NORTH TO KEEP MCS ACTIVITY JUST NORTH OF NC... ALTHOUGH THIS WILL CERTAINLY NEED TO BE MONITORED. WILL ADD A SMALL DIURNAL POP TO THE NORTHWEST COUNTIES ON TUE... AND BEEF UP WED POPS AREAWIDE WITH THE GFS FAIRLY CONSISTENT IN DEVELOPING A DECENT SURFACE LOW OVER VA & PW VALUES CONTINUING ABOVE NORMAL. THEN THE UPPER TROUGH DEEPENING ALONG THE WEST COAST SHOULD INDUCE AN INCREASE IN RIDGING OVER THE DEEP SOUTH AND SOUTHEAST STATES... WHILE INCREASED TROUGHING OVER ERN CANADA & NEW ENGLAND SHOULD TURN 850 MB FLOW MORE WNW OVER NC. WITH THIS POSSIBLE INCREASE IN CAPPING & DECREASE IN MOISTURE... WILL LEAVE FORECAST DRY FOR NOW DAYS 6/7. WILL MAKE FEW IF ANY NOTABLE CHANGES TO TEMPS THROUGH THE PERIOD. && .RAH WATCHES/WARNINGS/ADVISORIES... NC...NONE. && $$ HARTFIELD nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 924 AM EDT SAT MAY 15 2004 .DISCUSSION...THE SURFACE HIGH REMAINS ANCHORED E OF NC WITH THE RIDGE EXTENDING WWD INTO AL. THIS HIGH IS WINNING THE BATTLE WITH THE COLD FRONT TO THE WEST, WHICH HAS NEARLY STALLED. IT IS MAKING ONLY VERY SLOW EWD PROGRESS ACROSS MS. THE UPPER LEVEL VORT LOBE SEEMS TO BE MAKING BETTER HEADWAY AS WATER VAPOR IMAGERY SHOWS THE DRYING BEHIND THIS FEATURE MARCHING STEADILY EWD ACROSS THE LOWER MS VALLEY. CIRRUS CLOUDS ASSOCIATED WITH THE SHORT WAVE ARE ALREADY IMPINGING ON OUR WRN ZONES. THE MODELS ALL SHOW THE VORT LOBE EASING INTO AL BY 00Z WITH THE FRONT MAKING LITTLE IF ANY ADDITIONAL EWD PROGRESS. && .UPDATE...CURRENT POP DISTRIBUTION LOOKS REASONABLE. PLAN TO MAKE ONLY MINOR MODIFICATIONS, MAINLY TO REORIENT THE 30 POP AREA IN A MORE N/S FASHION TO INCLUDE MORE OF THE FL PANHANDLE AND LESS OF SW GA. THE MAX TEMP FORECAST MAY BE A DEGREE OR TWO HIGH, BUT WILL MONITOR A FEW MORE OBSERVATIONS BEFORE MAKING ANY CHANGES THERE. PLAN TO SHIFT WINDS TO A MORE SLY DIRECTION IN THE SEA BREEZE AREAS THIS AFTERNOON. && .MARINE...FOR THE THIRD MORNING IN A ROW, WE'VE SEEN AN ELY SURGE KICK WINDS UP OVER THE COASTAL WATERS INTO THE EXERCISE CAUTION RANGE. THE LATEST OBSERVATIONS INDICATE SUSTAINED WINDS ARE NOW AROUND 15 KT, SO WE DO NOT PLAN TO INSERT ANY HEADLINES. SIMILAR TO YESTERDAY, WE EXPECT WINDS TO DIMINISH AS THEY VEER DURING THE DAY TODAY. VERY LITTLE CHANGE FROM THIS DIURNAL FLUCTUATION IS EXPECTED OVER THE WATERS DURING THE NEXT COUPLE OF DAYS. && .FIRE WEATHER...ALTHOUGH THE MINIMUM RH WAS ONLY ABOUT 32-33%, CTY HAD 5-6 HOUR DURATIONS BELOW 35% YESTERDAY. TODAY'S 12Z KTLH SOUNDING SHOWS AN INCREASE IN LOW LEVEL MOISTURE OVER YESTERDAY WITH THE PW UP ABOUT 1/4 INCH TO 1.21 INCHES. RUC AND MESO ETA FORECASTS INDICATE MIN RH STAYING ABOVE 35% TODAY, EVEN ACROSS THE ERN BIG BEND. SO, WE DO NOT ANTICIPATE ANY SURPRISES TODAY, BUT WILL KEEP AN EYE ON THIS AREA THOUGH. && .PREV DISCUSSION... 145 AM EDT SAT MAY 15 2004 SHORT TERM...TODAY & SUNDAY. MODELS ARE OVERALL CONSISTENT WITH TAKING FRONTAL BOUNDARY TO AROUND MS/AL STATE-LINE & WITH SOME UPPER ENERGY MOVING NE ALONG IT. MOST OF THE ENERGY STAYS WEST OF THE CWA...WITH SOME SOUTHERN LOBE PARTS LIFTING OVER SE AL & FL PANHANDLE. SLIGHT TO CHANCE POP REMAINS GOOD FORECAST. SUNDAY WASHES THE FRONT OUT OVER SAME AREA...THEN DRIFTS IT BACK WEST MORE WITH SURFACE RIDGING BUILDING IN OVER THE SE U.S. SEA BREEZE REMAINS THE MAIN TRIGGER FOR CONVECTION OVER THE CWA. PRECIP WATER VALUES ARE UP A BIT WITH MAINLY AFTERNOON INSTABILITY WITH LI AROUND -1 TO 0. SOME SLIGHT TO 30% POP BEST FORECAST AT THIS TIME. TEMPS REMAIN IN THE MID TO UPPER 80S. ETA & GFS TIME-HEIGHT CROSS-SECTIONS INDICATE LOW LEVEL MOISTURE OVER CWA...BUT OMEGA LIFT QUITE LIMITED. LONG TERM...MONDAY THROUGH FRIDAY. SURFACE & UPPER RIDGING TO DOMINATE THE PERIOD OVER THE SE U.S. SEA BREEZE TRIGGER WOULD BE MAIN FOCUS OF AFTERNOON TO EARLY EVENING CONVECTION. BUT WILL BE QUITE LIMITED WITH SLIGHT CHANCES. TEMPS WARM A BIT TO UPPER 80S TO LOWER 90S. SOME WEAKENING IN THE PATTERN FRIDAY WITH A POSSIBLE TROUGH A TAD HIGH POP. && .PRELIMINARY POINT TEMPS/POPS... TLH 88 65 86 65 / 20 10 30 20 PFN 84 67 84 66 / 20 10 30 20 DHN 86 65 85 66 / 30 20 40 20 ABY 87 64 85 65 / 30 20 40 20 VLD 88 65 86 65 / 20 10 30 20 CTY 89 65 88 65 / 10 05 30 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. && $$ MCT/MAW fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1030 AM CDT SAT MAY 15 2004 .DISCUSSION...WIND FLOW ABOVE THE SURFACE BECAME NORTHEASTERLY EARLY TODAY...ALLOWING THE STRATOCUMULUS CLOUD DECK TO RETROGRADE WESTWARD TO THE ILLINOIS RIVER AGAIN. RUC MODEL SUGGESTS THESE 925H WINDS TO BECOME MORE NORTHERLY BY MIDDAY...ALLOWING A HALT TO THIS PROGRESSION...AND ALLOWING APPROACHING HIGH PRESSURE AND MAY SUN TO START TO ERODE WESTERN EDGE. WILL CONTINUE TO BE OPTIMISTIC IN THE WESTERN PORTION OF THE CWA IN REGARDS TO SUNSHINE THIS AFTERNOON ...BECOMING PARTLY SUNNY. HOWEVER...RH PROGS SUGGEST EAST WILL HAVE A HARD TIME REALIZING MUCH SUN BEFORE THE END OF THE AFTERNOON. HAVE BUMPED DOWN EXPECTED HIGH TEMPS IN THE EAST AS A RESULT. FORECAST/GRID UPDATE ALREADY OUT. && .PREV DISCUSSION...00Z GFS AND ETA MODELS FAIRLY SIMILAR THROUGH THE SHORT TERM ON HOW THEY HANDLE RIDGING OVER REGION AND TIMING OF NEXT FRONTAL SYSTEM LATE ON MONDAY. MAIN FORECAST PROBLEM OVER THE NEXT 48 HOURS WILL BE CLEARING AND TEMPS. SHORT TERM...TODAY THROUGH MONDAY NIGHT...DESPITE FRONT WELL TO THE EAST OF ILLINOIS AS OF 07Z...ANOTHER WAVE HAS DEVELOPED ALONG THE BOUNDARY AND MOVED NORTH TOWARDS ILLINOIS. SO AS LOW CLOUDS GRADUALLY CLEAR FROM WEST TO EAST...MID AND HIGH CLOUDS HAVE INVADED THE REGION. SO WILL START OFF AS MOSTLY CLOUDY TODAY AND GRADUALLY CLEAR FROM WEST TO EAST. THESE CLOUDS WILL ALSO KEEP FOG DEVELOPMENT FROM BECOMING WIDESPREAD THIS MORNING AND WILL AFFECT HIGH TEMPS TODAY...WITH COLDEST CONDITIONS IN THE EAST. BY TONIGHT...WE WILL BE PARTLY CLOUDY TO MOSTLY CLEAR...STILL HAVE PLENTY OF LOW LEVEL MOISTURE AND WINDS DIMINISHING TO LESS THAN 5 KTS...SO SOME FOG DEVELOPMENT IS NOT OUT OF THE QUESTION. WILL WAIT TIL CLOSER TO ZONE ISSUANCE TIME TO DECIDE ABOUT MENTIONING IT IN THE ZONES FOR LATE TONIGHT. ON SUNDAY...RIDGE MOVES TO OUR EAST...ALLOWING WINDS TO RETURN TO THE SOUTH AND BRINGING IN WARMER CONDITIONS FOR THE LAST HALF OF THE WEEKEND. THIS WARMING TREND WILL CONTINUE INTO MONDAY. WILL SEE AN INCREASE IN CLOUD COVER ON MONDAY AS NEXT FRONTAL BOUNDARY DROPS SOUTHEAST OUT OF THE UPPER MIDWEST. MODELS CONTINUE TO SLOW DOWN ITS PROGRESSION SOUTH...SO JUST KEPT 20 POPS IN THE N FOR LATE MONDAY AFTERNOON. STILL SOME QUESTION ON EXACT POSITION OF FRONT...SO KEPT MENTION OF RAIN IN REMAINDER OF FORECAST FOR NOW. LONG TERM...TUESDAY THROUGH FRIDAY... IN THE LONGER TERM...MODELS STILL HAVING A PROBLEM DEALING WITH STAGNANT ZONAL FLOW WHICH KEEPS BOUNDARY IN THE VICINITY OF ILLINOIS...SO NO MAJOR CHANGES MADE TO THE EXTENDED FORECAST. KEPT CHANCES OF RAIN IN THROUGH THE PERIOD. && .ILX WATCHES/WARNINGS/ADVISORIES... IL...NONE. && $$ PLAHMER/BYRD il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAKE CHARLES LA 945 AM CDT SAT MAY 15 2004 .SHORTWAVE CURRENTLY OVER SCNTRL LA FORECAST BY RUC TO MOVE ONLY VERY SLOWLY TO THE EAST TODAY. STILL SEEING SOLID COVERAGE OF SHOWERS AND ISOLATED TSTMS OVER EXTREME SERN PORTION OF CWA EXTENDING SWD INTO THE COASTAL WATERS. THIS AREA OF PRECIP WILL BE VERY SLOW TO MOVE OUT TODAY. OTHERWISE MUCH DRIER DAY ACROSS THE REST OF THE REGION AS KLCH 12Z SOUNDING SHOWING PWS OF 1.08" WHICH IS QUITE A BIT LOWER THAN THE 1.87" AT THIS TIME YESTERDAY. LOW CLOUDS HAVE DEVELOPED BACK BEHIND THE FRONT AND WILL BE TOUGH TO BREAK UNTIL THIS AFTERNOON. WILL UPDATE ZONES TO ADJUST CLOUD COVER AND POPS. && .PRELIMINARY POINT TEMPS/POPS... LCH 81 65 85 67 / 10 0 20 10 BPT 82 65 86 67 / 10 0 10 10 AEX 79 63 84 64 / 20 0 20 10 LFT 80 65 84 67 / 30 0 20 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. && .PREVIOUS DISCUSSION...UPPER LEVEL VORT MAX OVER LAFAYETTE THIS MORNING WILL CONTINUE TO MOVE EAST ALLOWING FOR DRIER AIR TO MOVE IN TO THE ENTIRE CWA. COOL FRONT HAS PUSHED OFFSHORE ALLOWING FOR COOLER TEMPERATURES TO FILTER DOWN INTO THE CWA. TEMPERATURES HAD COOLED INTO THE MID TO UPPER 60S SO FAR THIS MORNING. WATER VAPOR SHOWS CONSIDERABLE DRYING TAKING PLACE THROUGH SE TEXAS AND WESTERN LA. SOME REMAINING MOISTURE OVER THE EASTERN PART OF THE CWA WILL ALLOW FOR RAIN..ALTHOUGH LESS IN COVERAGE AND INTENSITY...WILL CONTINUE THROUGH THE MORNING HOURS BEFORE TAPERING OFF COMPLETELY BY EARLY AFTERNOON. LOW TO MID CLOUDS WILL HANG AROUND THROUGH THE AFTERNOON BEFORE BREAKING UP SOMEWHAT. APPEARS RH VALUES TO HANG IN AT 80 PERCENT OR BETTER FROM THE SURFACE TO JUST BELOW 700 MB. WILL ADJUST TEMPERATURES EVER SO SLIGHTLY DOWNWARD TO ACCOUNT FOR SIGNIFICANT STANDING WATER OVER LAND AND OF COURSE SOME CLOUD COVER. HEATING WILL BE OFFSET SOME AS IT GOES TO WORK IN EVAPORATING THIS TRULY REMARKABLE RAIN SOAKED RECENT EVENT. SOUTHERLY FLOW RETURNS AGAIN ON SUNDAY AS THE FRONT BACKS UP AS A WARM FRONT. COULD SEE ONE OR TWO SHOWERS POP UP ON SUNDAY. THE NEW WEEK BEGINS ON MONDAY WITH INCREASING MOISTURE...HOWEVER...THE UPPER LEVEL PATTERN SUPPORTS ONLY THE USUAL AFTERNOON SHOWERS AND THUNDERSTORMS WITH DAYTIME HEATING AND SOME SEABREEZE ACTIVITY. WEAK HIGH PRESSURE IN THE UPPER LEVELS WILL RETURN BY MID WEEK WITH RAIN CHANCES NEAR NORMAL THROUGH FRIDAY. && $$ 06/06 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1057 AM EDT SAT MAY 15 2004 .DISCUSSION... THE MAIN CONCERN WITH THIS UPDATE IS THE TEMPERATURES AND WIND FOR THIS AFTERNOON. WATER VAPOR AND RUC/ETA SHOWING SEVERAL WEAK SHORTWAVE MOVING THROUGH THE BASE OF A LONGWAVE TROUGH. THE FIRST IS MOVING THROUGH THE UPPER MICHIGAN THIS MORNING. THESE ARE HELPING TO GENERATE CUMULUS CLOUDS ACROSS THE AREA. GRB/APX 12Z RAOBS SHOWING A STRONG INVERSION AROUND 850MB. SURFACE ANALYSIS INDICATES A DOME OF HIGH PRESSURE OVER THE UPPER GREAT LAKES AND THE UPPER MISSISSIPPI RIVER VALLEY. A COLD FRONT STRETCHES FROM A LOW OVER NORTHERN ONTARIO THROUGH SOUTHERN MANITOBA INTO THE NORTHERN HIGH PLAINS. THE HIGH WILL REMAIN OVER THE FORECAST AREA THIS AFTERNOON. THE SHORTWAVE WILL CONTINUE TO GENERATE LOW CLOUDS THIS AFTERNOON. SURFACE DEW POINTS ARE IN THE UPPER 30S OVER WISCONSIN. THE INVERSION AROUND 850MB WILL CAP THE GROWTH SO NO SHOWERS OR THUNDERSTORMS EXPECT. THE LIFTED INDEX WILL BE AROUND 11 THIS AFTERNOON. ETA SOUNDING FORECAST INDICATES THAT MID AND HIGH CLOUDS WILL ALSO DEVELOP OVER THE FORECAST AREA BY LATE AFTERNOON GENERALLY ABOVE 500MB. CONDITIONS BELOW 500MB WILL FAIRLY DRY. WILL KEEP A MENTION OF CLOUDS. A 40 KNOT LOW LEVEL JET WILL SHIFT INTO WESTERN MINNESOTA THIS AFTERNOON HOWEVER WINDS SHOULD REMAIN FAIRLY LIGHT OVER THE U.P. AS THE HIGH CENTER MOVES EAST TODAY...EXPECT TO SEE WINDS REMAINING FAIRLY LIGHT AND SWINGING WEST. INCREASE CLOUD COVER SHOULD LIMIT HEATING. GUIDANCE PRODUCTS LOOK REASONABLE. AS THE HIGH MOVES EAST...WINDS WILL BECOME MORE SOUTHWEST TONIGHT. SOUNDING FORECAST SUGGEST THAT THE CLOUDS WILL LOWER OVERNIGHT. THUS EXPECT TO SEE VERY LITTLE TERRESTRIAL RADIATIONAL COOLING. THUS TEMPERATURES SHOULD ONLY LOWER ABOUT 10 DEGREE OVER WHICH SHOULD BE CLOSE TO WHAT GUIDANCE SUGGEST. WILL NOT MAKE ANY CHANGES TO TONIGHT FORECAST YET. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 910 AM MDT SAT MAY 15 2004 .DISCUSSION...14Z SURFACE ANALYSIS SHOWED TROUGH EXITING THE CWA VIA SOUTH CENTRAL SD. COLD FRONT CROSSING THE MT/ND/CANADIAN BORDER. WATER VAPOUR HAD SHORTWAVE LEAVING VIA EASTERN SD. SUBSIDENCE/DRYING IN IT/S WAKE RESULTING IN PLENTY OF SUNSHINE THIS MORNING. TEMPERATURES HAVE RISEN QUICKLY AND GIVEN 12Z RUC...WILL BUMP UP HIGHS A BIT FOR THIS AFTERNOON WITH LESS CLOUDS. EXPECT COLD FRONT WILL HAVE LITTLE EFFECT ON THE WEATHER AS IT DOESN/T MOVE IN BEFORE 00Z. && .UNR WATCHES/WARNINGS/ADVISORIES... .SD...NONE. .WY...NONE. $$ HELGESON sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1040 AM EDT SAT MAY 15 2004 .UPDATE FOR DISCUSSION... .DISCUSSION... 1050 AM EDT SAT MAY 15 2004 FRONT JUST THRU PARKERSBURG AT 10 AM. NEW ETA AND RUC MODELS SHOW THIS FRONT ONLY VERY SLOWLY DRIFTING EAST THROUGH MID AFTERNOON... THEN PUSH EAST A LITTLE FASTER LATER THIS AFTERNOON BEHIND A SURFACE WAVE RIPPLING NORTHEASTWARD ALONG THE FRONT. THUS...SOME MAJOR CHANGES IN THE FORECAST THIS AFTERNOON EAST OF THE OHIO RIVER. WILL RAISE TEMPERATURES 3 TO 5 DEGREES DUE TO CLOUDS MOSTLY BEHIND THE FRONT...AND WILL KEEP POPS IN THE CHANCE CATEGORY FOR MUCH OF THE AFTERNOON. WILL HAVE TO WATCH THE POSSIBILITY OF TRAINING ECHOES WITH LOCALLY HEAVY RAIN ACROSS WESTERN AREAS THIS AFTERNOON DUE TO SLOW MOVEMENT OF THE FRONT. JMV && .PREVIOUS DISCUSSION... 359 AM EDT SAT MAY 15 2004 .SHORT TERM...THROUGH SUNDAY. WEAKENING COLD FRONT MOVES INTO FORECAST AREA TODAY THEN STALLS WITHIN FORECAST AREA TONIGHT...ON A SOUTHWEST TO NORTHEAST LINE. ON SUNDAY...THIS FRONT MAY TAKE ON A MORE WEST TO EAST ORIENTATION BUT CANNOT IMAGINE A FRONT THIS WEAK MAKING MUCH SOUTHWARD HEADWAY DURING THE DAY THIS TIME OF YEAR. A PAIR OF WEAK UPPER LEVEL SHORT WAVES MOVES THROUGH THE SOUTHWEST FLOW. THE FIRST PUSHES RAIN INTO THE ARA THIS MORNING...THE SECOND MAY ACTUALLY RE-INVIGORATE IT A BIT LATE TODAY WHILE GIVING THE FRONT ONE MORE NUDGE EASTWARD. THUNDERSTORM POTENTIAL TODAY IS LIMITED BY LACK OF SHEAR OR UPPER SUPPORT. THERE IS JUST ENOUGH INSTABILITY OWING LARGELY TO HIGH PWS (1.5-1.7) TO SUPPORT SOME THUNDER. FRONT STILL LAYS ACROSS AREA SUNDAY BUT UPPER SUPPORT IS GONE...EVEN NEGATIVE. ATMOSPHERE DOES BECOME UNSTABLE AGAIN DURING THE AFTERNOON THOUGH. THIS MAY ESPECIALLY BE THE CASE NORTH WHERE THERE IS THE MOST SUNSHINE. OPTED TO EXCLUDE THUNDER FROM LATE TONIGHT THROUGH EARLY SUNDAY. THIS IS LARGELY AN EXTRAPOLATION OF WHAT IS OCCURRING NOW...FRONT/UPPER SUPPORT SHOULD BE EVEN WEAKER. ANY SUNSHINE AT ALL FIRST THING THIS MORNING WILL TAKE US ABOVE MAV FOR HIGHS TODAY SO ABOVE MOST SITES. USED A BLEND TONIGHT AND SUNDAY. .LONG TERM...SUNDAY NIGHT AND BEYOND. WEAK UPSLOPE FLOW AND HIGHER BL RH LINGERS THE FIRST HALF SUNDAY NIGHT...SO CARRIED SCHC/CHC POPS FOR EXTREME EASTERN ZONES...WHILE BOOSTING SKY COVER. THE START OF THE NEW WORK WEEK BRINGS H5 RIDGE BACK INTO THE PICTURE WITH INCREASING HEIGHTS AND TEMPS ALOFT. ETA/GFS DIFFER IN STRENGTH OF MID LEVEL WAVE RUNNING THE RIDGE FROM THE SOUTHWEST MONDAY. GFS STRENGTHENS FEATURE AS IT HEADS TOWARD THE OH VALLEY...WHILE THE ETA MAINTAINS SAME LEVEL OF INTENSITY. THIS CAUSES TRICKLE DOWN EFFECTS AS THE GFS BRINGS A NICE POCKET OF H2 UPR LVL DIV THROUGH DURING THE PEAK HEATING HOURS...CREATING GREATER AREAL COVERAGE OF TRW...WHILE ETA CONFINES QPF E OF OH RIVER. NOT TOTALLY SOLD ON GFS SOLUTION...BUT WON'T COMPLETELY DISCARD SINCE ITS NOT GRID SCALE FEEDBACK...HOWEVER PER THE PROFUSE AMOUNT OF MSTR...EXPANDED CHC POPS TO ENTIRE CWA. REMAINING PART OF THE WEEK HINGES ON THE WHEREABOUTS OF THE BAROCLINIC ZONE...WHICH BECOMES STATIONARY WEDNESDAY. H5 RIDGE WEAKENS ALLOWING WESTERLIES TO COLLAPSES INTO THE LOWER GREAT LAKES DAY 4...WHILE THE CLOSE PROXIMITY OF HIGH PRESSURE BEHIND IT...WINDS IN THE COLD SECTOR BECOME EASTERLY...THUS HALTING SOUTHWARD ADVANCEMENT. GFS DROPS FRONT THROUGH WED...HOWEVER GIVEN RECENT TRENDS...EXPECT LATER MODELS TO RETARD SOUTHWARD PROGRESSION. THAT IN MIND...CWA REMAINS IN WARM SECTOR WITH INCREASING INSTABILITY EACH SUCCESSIVE DAY. LI/S FALL TO -4C WITH SBCAPES ECLIPSING 1.5KJ/KG TUES - THUR...NOT TO MENTION HIGH H8 DWPTS AND WARM CLOUD DEPTH. DYNAMICS RESIDE ALONG THE FRONT...SO NOT CONCERNED WITH SVR WX POTENTIAL AS I AM HIGH WATER THREAT PER TRAINING PATTERN ESTABLISHING. LITTLE TO ANY CHANGES DONE TO EXISTING MAX/MIN T GRIDS DURING THIS PERIOD. TRM/29 && .AVIATION... 659 AM EDT SAT MAY 15 2004 COLD FRONT APPROACHES FROM THE WEST TODAY AND MOVES INTO WV LATE TODAY AND TONIGHT. FRONT WILL STALL ON A SOUTHWEST TO NORTHEAST LINE ACROSS WV OVERNIGHT. RAIN ARRIVES FROM THE WEST THIS MORNING AND WILL REDUCE CIGS AND VIS TO MVFR TO PERHAPS IFR AS IT GRADUALLY EDGES EAST TODAY. CONDITIONS MAY IMPROVE TOWARD VFR LATER THIS AFTERNOON THEN FALL BACK TO AT LEAST IFR OVERNIGHT IN LOW CLOUDS AND DRIZZLE. LIGHT SW FLOW TODAY THEN BRIEF LIGHT NORTHERLY FLOW NORTHERN SITES BEHIND FRONT LATE TODAY. CALM TONIGHT AS FRONT WEAKENS. THUNDERSTORMS POSSIBLE TODAY AND CODED UP MOST SITES AS SLOWER FRONT WILL YIELD MORE OPPORTUNITY FOR STORMS TO FIRE THIS AFTERNOON THAN EARLIER THOUGHT.. ANY THUNDERSTORM THAT DOES OCCUR TODAY MAY HAVE GUSTY WINDS BUT WILL BUT WILL REMAIN BELOW SEVERE LIMITS. TRM && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. VA...NONE. KY...NONE. OH...NONE. && $$ wv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 415 PM EDT SAT MAY 15 2004 .DISCUSSION... WV IMAGERY AND RUC ANALYSIS INDICATED A TROF OVER CNTRL CANADA AND A RDG OVER ERN NOAM BUT A MAINLY ZONAL PATTERN OVER THE WEST/CNTRL CONUS WITH NMRS WEAK SHRTWVS. AT THE SFC...WAA PATTERN HAD DEVELOPED FROM THE PLAINS INTO THE UPR MS VALLEY BTWN HI PRES OVER THE WEST/CNTRL GRT LAKES AND TROF OVER THE HIGH PLAINS. A SHRTWV OVER ERN SODAK INTO SW MN HAS BROUGHT SOME -SHRA INTO SW MN BUT MAINLY JUST INCREASING MID/HIGH CLDS FROM MN INTO WRN UPR MI. ANOTHER OVER ERN ND SUPPORTED A BAND OF SHRA AND A FEW TSRA. MOISTURE HOWEVER WAS VERY LIMITED WITH DEWPOINTS FROM THE MID AND 40S OVER THE DAKOTAS TO THE 30S OVER MN. STRONGER SHRTWVS LURKED UPSTREAM OVER SE SASK INTO ERN MT AND OVER ERN OR AS UPR LVL JET ENERGY MOVE IN FROM THE ERN PAC. TONIGHT INTO EARLY SUN...EXPECT SD/MN TO BRING INCREASING MID/HIGH CLOUDS THIS EVENING...PER VIS/IR SATELLITE TRENDS. MDLS SUGGEST POSSIBILITY OF SOME -SHRA OVERNIGHT AS ND SHRTWV MOVES THROUGH UPR MI OVERNIGHT. WHILE THERE IS DECENT DYNAMIC SUPPORT FROM 700-300 QVECTOR CONV WITH MODERATE NET 290K ISENTROPIC LIFT...WITH LACK OF LOW LVL MOISTURE...ONLY LOW POPS INCLUDED FOR MAINLY JUST LIGHT SHOWERS OR SPRINKLES OVER THE WEST HALF. LATE SUN...AS FRONTAL SYSTEM NEARS WEST UPR MI...ENOUGH MOISTURE RETURN WITH DEWPOINTS INTO THE MID AND UPPER 40S MAY RESULT IN WEAK CAPE OF AROUND 400 J/KG WITH LITTLE CIN AND MID LVL LAPSE RATES NEAR 7C/KM. EVEN WITH WEAK LAKE BREEZE CONTRIBUTIONS OR LOW LVL CONV AHEAD OF THE FRONT...SHRA/TSRA SOME SCT/ISOLD MAY BE POSSIBLE. SUN NIGHT INTO MON...MDLS WERE IN REASONABLE AGREEMENT WITH SFC AND MID LVL FIELDS. AS PAC NW SHRTWV MOVES TOWARD THE LAKES AND UPR LVL DIV WITH RIGHT ENTRANCE OF JET DEVELOPS AND MORE SIGNIFICANT MOISTURE MOVES IN (UPSTREAM PWAT TO 1.00-1.25 INCHES) 295K-300K ISENTROPIC LIFT WITH 50-60 KT INFLOW ABV 850 MB WARM FRONT FRONT WILL SUPPORT BROAD AREA OF SHRA FROM MN/WI INTO UPR MI. UNCERTAINTIES ARISE WITH POSSIBLE MCS DEVELOPMENT TO THE SW AND ITS AFFECT ON MOISTURE INFLOW AND RAINFALL AMOUNTS. HOWEVER...GIVEN PROGRESSIVE NATURE OF THE SYSTEM AND STRENGTH OF FRONTAL DYNAMICS PCPN WILL BE LIKELY ACRS THE AREA. EVEN THOUGH ETA 1000-700 MUCAPE SHOWS INSTABILITY MAINLY S OF UPR MI AS ETA INDICATES MAINLY STABLE RATHER THAN CONVECTIVE PCPN. HOWEVER...STRENGTH OF DYNAMICS JUSTIFY CONTINUED MENTION OF SOME TSRA. WENT WITH COMPROMISE WHERE DIFFERENCES NOTED NOTED IN TIMING/PLACEMENT OF QPF BTWN THE ETA/GFS. BY MIDDAY MON INTO THE AFTERNOON AS THE LOW LIFTS NE OF LK SUPERIOR AND THE FRONT MOVES INTO SE UPR MI...ENOUGH INSTABILITY MAY DEVELOP TO SUPPORT STRONGER TSRA. MON NIGHT INTO TUE...SHRTWV MOVING THROUGH NRN ONTARIO AND ASSOCIATED LGT PCPN SHOULD REMAIN NORTH OF UPR MI. OTHERWISE...HIGH PRES BUILDING IN WITH DRY ADVECTION AND WEAK SRLY FLOW SHOULD BRING PARTLY TO MOSTLY SUNNY SKIES AND MILD CONDITIONS...INLAND TEMPS IN THE MID TO UPPER 60S. WED-SAT...MDLS WERE IN REASONABLE AGREEMENT WITH OVERALL PATTERN WITH CONTINUED FAST WRLY FLOW THROUGH THE NRN CONUS AS THE CNTRL CANADA TROF GRADUALLY SHIFTS TO THE EAST AS HGTS FALL OVER THE WEST. ANOTHER CHANCE OF SHRA/TSRA EXPECTED WITH FRONT/TROF MOVING THROUGH UPR MI. THE CANADIAN/UKMET AND 06Z/12Z GFS SUGGEST BEST CHANCE FOR PCPN FROM LATE WED INTO WED NIGHT NIGHT. HIGH PRES BUILDING INTO THE AREA FRI INTO SAT SHOULD KEEP THE AREA DRY. WHILE GFS SUGGESTS POSSIBILITY OF SOME LGT PCPN WITH WEAK CLIPPER SHRTWVS... FORCING/MOISTURE LOOKS TOO WEAK TO ADD PCPN AT THIS POINT. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 330 PM CDT SAT MAY 15 2004 .DISCUSSION... STRENGTH AND TIMING OF PRECIPITATION AND TEMPERATURES THE PRIMARY CONCERNS THIS FORECAST PACKAGE. AFTER MORNING LOWS IN THE 30S (BOTH LNK AND OMA WERE TWO DEGREES AWAY FROM THEIR DAILY RECORD LOW)...TEMPERATURES ARE BEGINNING TO RECOVER INTO THE 60S. THE LIGHT PRECIPITATION AND THICKER CLOUDINESS HAS BEEN SHIFTING OFF TO THE EAST. THE LATEST SURFACE ANALYSIS HAD SFC HIGH PRESSURE CENTERED OVER LAKE MICHIGAN...WITH SOUTH FLOW CWA-WIDE. THE WINDS WERE STRONGER AT 10 TO 20 MPH IN THE LNK AND OFK AREAS. A SFC TROF WAS NOTED WEST OF VTN AND OVR THE WRN DAKOTAS. WEST OF THIS AREA...DEWPOINTS WERE IN THE 20S AND 30S WITH WEST OR NORTHWEST WINDS. EAST OF THIS TROF...WINDS WERE FROM THE SE WITH DEWPOINTS IN THE 40S. THIS MORNING OF NOTE ON THE OAX SOUNDING WAS THE RH AT 700MB. ON THE UA MAPS...THERE WAS A NICE LOW LEVEL JET WITH 40KTS FROM THE SW AT LBF AND DECENT WAA AT BOTH 850 AND 700 MB. PER THE 88D REFLECTIVITY MOSAIC...THE ECHOES ARE PUSHING OUT OF THE CWA...HOWEVER...THERE HAS BEEN SOME RECENT DEVELOPMENT OUT NEAR VALENTINE...IN THE VICINITY OF THE SFC TROF AND THE THETA-E RIDGE. ALSO SPC RUC COMPOSITE SHOWING AREA OF HIGHER CAPES NEAR THIS TROF. SHORTWAVE TROF OVER THE DAKOTAS AND NEBRASKA TO PRESS EASTWARD INTO MINNESOTA/IOWA/WISCONSIN THIS EVENING...MEANWHILE...NEXT SHORTWAVE TROF OVER OREGON AND NORTHERN CALIFORNIA TO MOVE ACRS THE SIERRAS AND INTO THE WESTERN PLAINS. THIS VIGOROUS WAVE TO BRING STRONG SYNOPTIC LIFT ACRS THE STATE SUNDAY AND INTO IA BY SUNDAY EVENING. THIS WAVE WILL DRAG THE SURFACE FRONT SOUTHWARD SUNDAY NIGHT...WITH THE FRONT SLOWLY SAGGING SOUTH INTO NORTHEAST KANSAS AND NORTHERN MISSOURI MONDAY AS HIGH PRESSURE BUILDS IN ACRS THE FCST AREA. TONIGHT...LOOK FOR THE LOW LEVEL JET TO STRENGTHEN OVER THE WRN PLAINS WITH CONVERGENCE INCREASING...WAA AT BOTH 850 AND 700MB...LIFT WITH THE APPROACHING MID LEVEL SHORTWAVE TROF. WILL LOOK AT RADAR AND ADJUST EVENING SPRINKLES...THEN ATTENTION TURNS TO APPROACHING SYSTEM. INCLUDED SLIGHT CHC POPS FOR -TSRA OVERNIGHT NW COUNTIES. UPR LEVEL JET TO HEADS TOWARD MT AND INTO THE NORTHERN PLAINS OVERNIGHT AND THE PLAINS AND UPR GREAT LAKES SUNDAY. HAVE LIKELY POPS NW ZONES SUNDAY MORNING WITH CHC POPS INTO OFK AND OLU AREAS. BY AFTERNOON...CONTINUE TO SPREAD CHC POPS FARTHER SE. SOUTH WINDS IN THE BREEZY OR WINDY CATEGORY. CLOUDS AND PRECIP COULD HOLD TEMPS BACK. FOR NOW HAVE 70S N AND 80S S. SUN...ALL OF THE CWA IS IN THE OUTLOOK AREA.THERE REMAINS SOME QUESTION AT TO THE RH THAT WILL BE AVAILABLE WITH THE SYSTEM SUN EVENING. WITH FAVORABLE DYNAMICS...SHEAR...AND INSTABILITY...THIS OUTLOOK AREA MAY BE MODIFIED TO INCLUDE A MODERATE AREA. HAVE LIKELY POPS DURING THE EVENING...AND DROP THESE FURTHER SOUTH OVERNIGHT SUNDAY. WILL NEED TO MONITOR LOCAL STORM DEVELOPMENT SUNDAY NIGHT FOR LOCAL FLASH FLOODING DUE TO EXPECTED HIGHER PWS AND MOVEMENT OF STORMS. THUNDERSTORM DEVELOPMENT IN THE VICINITY OF THE SFC FRONT IS MOST LIKELY MONDAY AND MONDAY NIGHT. STEEP LAPSE RATES...SHEAR AND MOISTURE REMAINS AVAILABLE...THEREFORE AREA NEAR THE FRONT ACRS SRN NEB AND SW IA REMAINS IN SLIGHT RISK FOR SEVERE IN DAY THREE OUTLK. TUESDAY THROUGH SATURDAY...A MID LEVEL TROF GENERALLY REMAINS OVER THE WEST COAST WITH SOUTHWEST FLOW DOMINATING AT THE 850MB AND AMPLE MOISTURE AVAILABLE. THE MID LEVEL RIDGE OVER THE SOUTHERN PLAINS MAINTAINS ITSELF...BEFORE BEGINNING TO BREAK DOWN FRIDAY AND SATURDAY AS THE TROF MAKES SOME EASTWARD PROGRESS. THE CURRENT FORECAST HAS FAIRLY HIGH POPS WITH SHOWERS AND THUNDERSTORMS IN FOR TUESDAY. DO NOT SEE ANY REASON TO DEVIATE FROM THIS. SFC FRONT PROGGED OVER KS AND MO WITH 850MB FLOW PERPENDICULAR TO THE FRONT. INITIALLY STRONGER FOCUS OVER NEBRASKA SHIFTS TO IOWA DURING THE EVENING. TEMPERATURES IN THE 60S AND 70S TUESDAY SHOULD WARM INTO THE 70S AND 80S WEDNESDAY AS THE SFC FRONT LIFTS NORTHWARD (PER CANADIAN/GFS/ECMWF). WITH THE FRONT DROPPING SOUTH AGAIN THU...SOME QUESTION AS TO HOW FAR N TO CARRY POPS. LEFT TEMPS IN THE 70S FOR THE MOST PART AND 80S S. LOCATIONS MAY BE HELD DOWN WITH CLDS AND PRECIP. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ ZAPOTOCNY ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 310 PM CDT SAT MAY 15 2004 .DISCUSSION...SHORTWAVE MOVING INTO SOUTHERN MN PASSED HARMLESSLY BY THIS AREA BUT THE ONE WITH VORTICITY MAX A LITTLE NORTHWEST OF JMS HAS GENERATED SOME HEAVY SHOWERS FOR MUCH OF THE DAY FROM JMS TO GFK BUT THEY WEAKENED SOME AS THEY HEADED INTO NORTHWEST MN. THESE SHOWERS FINALLY APPEAR TO BE BREAKING UP SOME BUT NEW CELLS ARE DEVELOPING EAST OF BIS ON A SURFACE TROUGH/DRY LINE. OF BIGGER CONCERN IS THE LINE OF STORMS DEVELOPING IN WESTERN ND WITH THE COOL FRONT. THIS LINE AND THE DRY LINE WILL LIKELY COMBINE TO CAUSE A SEVERE TSTORM THREAT FOR MUCH OF THE CWA BY THIS EVENING. .SHORT TERM...RUC SHOWS MOST PARAMETERS INDICATIVE OF LANDSPOUT FORMATION FOR NORTHEAST ND WITH THE BIGGEST NEGATIVE FACTOR BEING THE HIGH (6500-8500 FT AGL) LCL LEVELS. EVEN WITHOUT THAT THERE IS SOLID POTENTIAL FOR SOME SEVERE GUSTS AND HAIL GIVEN THE -26C 500 MB TEMPERATURE THERE WHILE THEY WILL BE IN THE LEFT/FRONT UPPER JET QUAD FOR STRONG LIFT. SO RAISED POPS TO LIKELY THERE AND ADDED SEVERE WORDING. FARTHER SOUTH...ALSO ADDED STRONG TSTORMS WORDING BUT KEPT THEM SCATTERED. FOR MON THE SHOWERS STILL LOOK GOOD FOR SOUTHEAST ND AND INTO WEST CENTRAL MN AND RAISED POPS THERE TO LIKELY. BUT OTHERWISE MADE MINOR CHANGES REGARDING IT. GULF OPENS FOR THIS EVENT AND ETA/GFS PUSH THE HIGH 850 MB DEW POINTS AS FAR AS ABR. STILL DO NOT BELIEVE THERE IS ANY CHANCE OF THUNDER FOR US WITH THESE SHOWERS GIVEN IT WOULD BE SIGNIFICANTLY NORTH OF THE 300 MB JET. GFS ALSO LOOKS OVERDONE IN QPF VALUES SINCE THEY EXCEED AVAILABLE PRECIPITABLE WATER. AN OUTSIDE CHANCE EXISTS FOR ITS 1.5 INCHES SINCE IT COULD LAST ALL MON AFTERNOON AND EVE. BUT THINK NCEP VALUES OF UP TO AN INCH ON OUR BORDER LOOKS GOOD. .LONG TERM (WED-SAT)...EXTENDED RANGE MODELS SUGGEST A MORE ZONAL FLOW PATTERN ALOFT FOR MOST OF THE EXTENDED PERIOD...ESPECIALLY COMPARED TO RECENT DAYS. BOTH THE GFS AND CANADIAN HAVE A CUTOFF LOW OVER THE WEST COAST WITH THE CANADIAN SOMEWHAT FASTER IN ABSORBING THIS SYSTEM INTO THE MEAN FLOW. THE GFS TIMING SEEMS MORE REASONABLE...SO WILL TREND THAT WAY. TEMPERATURES SHOULD MODERATE TO NEAR SEASONAL NORMALS FOR LATE NEXT WEEK. COLD FRONTAL PASSAGE EXPECTED WEDNESDAY NIGHT INTO THURSDAY MORNING. A BAND OF SHOWERS WITH FROPA STILL APPEARS REASONABLE DURING THIS TIME PERIOD. DEVELOPMENT OF A SIGNIFICANT CENTRAL PLAINS CYCLONE SHOULD TAKE PLACE NEXT WEEKEND. DUE TO THE SLOW MOVEMENT OF THE SYSTEM ACROSS THE PLAINS...IT APPEARS THAT A PROLONGED PERIOD OF PRECIPITATION IS POSSIBLE. THE TRENDS WITH THIS SYSTEM WILL DESERVE CLOSER EXAMINATION IN LATER FORECASTS DUE TO CURRENT HYDROLOGIC CONCERNS. .HYDROLOGY...NO CHANGES TO CURRENT RIVER AND OVERLAND FLOOD WARNINGS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...RIVER FLOOD WARNING FOR ROSEAU RIVER AT ROSEAU AND TWO RIVERS RIVER AT HALLOCK. AREAL FLOOD WARNING FOR ROSEAU AND MARSHALL COUNTIES UNTIL SUNDAY MORNING. && $$ GV/BB nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OHIO 255 PM EDT SAT MAY 15 2004 .DISCUSSION... VORT MAX RESPONSIBLE FOR ALL OF THE SHOWER ACTIVITY TODAY ACROSS THE AREA NOW ENTERING NW OHIO PER WATER VAPOR IMAGERY. BACK EDGE OF THE RAIN LINES UP QUITE WELL WITH BACK EDGE OF THE PVA ASSOCIATED WITH THE VORT. RADAR SHOWS THAT THE BACK EDGE OF PCPN IS ALREADY THRU TOL AND SHORT TERM VORTICITY FCST FROM THE RUC WOULD SUGGEST THAT THE RAIN WOULD BE FINISHED WEST OF THE I-71 CORRIDOR BY 23Z AND EAST OF THE ENTIRE FORECAST AREA BY 02Z. WILL THEREFORE GO WITH CAT POPS THIS EVENING IN THE ABOVE MENTIONED AREAS...AND WILL GO DRY WEST. MIGHT MENTION A FEW SPRINKLES WEST OF THE MAIN RAINFALL AREAS...BUT IWX AND IND RADARS ARE VERY DRY SO DOUBTFUL THAT MUCH IN THE WAY OF SPRINKLES OCCUR ONCE THE MAIN VORT PASSES BY. MAIN CONCERN FOR TONIGHT IS FOG. RAINFALL FROM TODAY HAS ALLOWED FOR PLENTY OF MOISTURE IN THE LOW LVLS. ALTHOUGH THERE IS SOME DRY ADVECTION FROM THE NW BEHIND THE VORT...THE FACT REMAINS THAT UPSTREAM DWPTS ARE STILL IN THE MID 40S. AS THE HIGH BUILDS IN OVERNIGHT...WINDS SHOULD LIKELY DECOUPLE AS A STRONG LOW LVL INVERSION SETS UP...TRAPPING THE MOISTURE UNDERNEATH. SEE NO REASON WHY FOG WOULD NOT FORM ACROSS MOST AREAS OVERNIGHT. IN FACT...IF THE WINDS CAN GO CALM...IS IS POSSIBLE THAT THE FOG COULD BECOME DENSE BY MORNING PER THE CROSSOVER TECHNIQUE. WILL THEREFORE GO WITH AREAS OF FOG...LOCALLY DENSE TONIGHT. EVENING/MID SHIFTS WILL NEED TO MONITOR FOR POSSIBLE DENSE FOG ADVY...ESPECIALLY IF ANY AREAS CAN SEE SOME PARTIAL CLEARING. AFTER SOME MORNING FOG...SUNDAY SHOULD BE A VERY NICE DAY UNDER HIGH PRESSURE WITH PRECIPITABLE WATER VALUES AROUND 0.50 INCH. 850MB TEMPS WARM TO AROUND +10C BY EVENING. UNDER FULL SUN...MIXING THIS DOWN SHOULD YIELD TEMPS AROUND 70 WEST AND THE MID-UPR 60S OVER NW PA. WITH LIGHT AND VARIABLE WINDS UNDER HIGH PRES...LAKE BREEZE WILL CERTAINLY BE A FACTOR NEAR LAKE ERIE WITH TEMPS IN THE LOWER-MID 60S NR THE IMMEDIATE SHORELINE. CONTINUED DRY SUN NIGHT WITH PRECIPITABLE WATER VALUES SLOWLY RISING IN RESPONSE TO WARM ADVECTION ON THE BACK SIDE OF THE HIGH. MAY ONCE AGAIN HAVE A LITTLE FOG TO CONTEND WITH. HOWEVER...WILL NOT INCLUDE IN THE FCST RIGHT NOW DUE TO THE WINDS INCREASING FROM THE SE OVERNIGHT ON THE BACK SIDE OF THE HIGH HELPING TO KEEP THE LOW LVLS MIXED. DWPT TEMPS WILL ALSO BE ON THE RISE SUN NIGHT...SO MIN TEMPS SHOULD ONLY LOWER TO THE MID 40S-LOWER 50S. MOST LIKELY SOME LOWER 40S OVER INLAND NW PA AS WINDS SHOULD BE ABLE TO DECOUPLE THERE. MIGHT SEE SOME INCREASING MID-HIGH CLOUDS ON MONDAY AS WARM ADVECTION INCREASES AHEAD OF THE DEVELOPING SYSTEM OVER THE PLAINS. HOWEVER...OVERALL SKIES SHOULD BE PARTLY TO MOSTLY SUNNY. GFS HAS PCPN MOVING INTO THE OH VLY IN THE WARM ADVECTION AREA WELL AHEAD OF THE MAIN SHORT WAVE IN THE PLAINS MON AFTN. WITH THE SIGNIFICANT DRY AIR IN PLACE AND LACK OF MAJOR DYNAMICS OR LIFT...AM HESITANT TO GO WITH ANY POPS FOR MONDAY DESPITE THE GFS MOS HAVING SMALL CHC POPS ON MONDAY. WITH THE AREA BEING IN THE WARM SECTOR...TEMPS SHOULD RISE INTO THE UPR 70S TO LOWER 80S. WILL CONTINUE TO BRING IN 30 PCT CHC POPS LATE MON NIGHT OVER THE FAR NW AHEAD OF THE COLD FRONT MOVING THRU NRN LOWER MICH BY 12Z TUE. THE ETA SHOWS STRONG UPR DVRG IN ASSOCIATION WITH THE RIGHT REAR OF THE JET MAX EXTENDING FROM LAKE SUPERIOR THROUGH QUEBEC MOVING INTO THE EXTREME NW BY 12Z. CONTINUED 50 POPS ON TUE WITH THE FRONT MOVING THRU THE AREA ON TUESDAY. THOUGHT ABOUT GOING LKLY POPS TUE...BUT THE FRONT WILL BE WEAKENING AS IT MOVES THRU THE AREA DUE TO THE BEST DYNAMICS BEING WELL NORTH. THE FRONT SLOWLY MOVES SOUTH TUE NIGHT...WITH THE GFS SUGGESTING DRYING AS HIGH PRES BUILD IN TEMPORARILY. HOWEVER...DO NOT WANT TO GET TOO CAUGHT UP ON TIMING THIS FAR OUT...SO WILL KEEP CHC POPS ALL NIGHT TUE NIGHT FOR THE ENTIRE AREA. BEST POPS WILL BE THE SOUTHERN FORECAST AREA. EXTENDED...AFTER THE FROPA TUE THE FRONT WILL SAG SOUTH TO KY. THIS SHOULD ALLOW FOR HIGH PRES TO BUILD IN BRIEFLY WED AFTN AND NIGHT CAUSING SOME DRY WX BEFORE THE FRONT MOVES BACK N AND STALLS OUT OVER OHIO. THE EXTENDED MODELS AND ENSEMBLES ARE IN VERY GOOD AGREEMENT IN SHOWING A PERSISTENT ZONAL FLOW OVER THE NORTHERN U.S. THRU DAY 7 WITH A FRONT BECOMING QUASI-STATIONARY OVER THE OHIO VLY. SO...AFTER WED NIGHT...WILL NEED TO KEEP CHC POPS THRU SAT. AS SAID YESTERDAY...THERE WILL LIKELY BE PERIODS OF DRY WX...BUT WITH THE FRONT NEARBY IT IS NEARLY IMPOSSIBLE TO TIME PCPN AND INDIVIDUAL WAVES. WILL THEREFORE GO WITH 30 POPS FOR EACH PERIOD THU-SAT. TEMPS WILL BE TOUGH DEPENDING ON THE LOCATION OF THE FRONT...BUT IT SEEMS LIKE THE WARMEST DAY WILL BE THU WHEN THE MDLS SUGGEST THAT THE FRONT WILL BE N OF THE AREA AS LOW PRES DEVELOPS OVER THE PLAINS IN RESPONSE TO A TROUGH DIGGING IN THE WEST. OVERALL...FCSTED TEMPS WILL BE NR SEASONABLE NORMS. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. && $$ MRD oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 245 PM EDT SAT MAY 15 2004 .PUBLIC... THROUGH DAY 3...RUC AND LOCAL MESOSCALE MODEL HAD A PRETTY GOOD HANDLE ON THE SURFACE-BASED CONVERGENCE WHICH APPEARS TO HAVE FORCED TODAY'S CONVECTION STREAMING ONSHORE...GENERALLY FROM BEAUFORT COUNTY NORTHWESTWARD. MODELS ARE SHOWING THIS TREND ENDING AFTER SUNSET TONIGHT...WITH NO NEW CONVERGENT AREA FORECAST TO DEVELOP OVERNIGHT OR SUNDAY. STILL CAN'T RULE OUT A SHOWER OR TWO AGAIN TOMORROW...BUT IT SHOULD BE PRIMARILY FORCED BY WHATEVER SEA BREEZE CAN BE GENERATED GIVEN THE SHALLOW NATURE OF THE MOISTURE. TEMPERATURES AND WINDS WILL GENERALLY FOLLOW PERSISTENCE THE NEXT THREE DAYS WITH LOW POPS. && .MARINE... PERSISTENCE THE KEY TO THIS PACKAGE AS RIDGE AXIS REMAINS ANCHORED. SE FLOW WILL DEVIATE FROM MORE ELY AT TIMES IN THE GEORGIA WATERS TO SSE IN THE SOUTH CAROLINA WATERS. WILL MAINTAIN THE MODERATE DIURNAL SPEED TRENDS ALONG THE LAND/SEA INTERFACE WHICH ARE ALREADY DEPICTED WELL IN OUR GRAPHICAL DATASET. WAVE WATCH MODEL STILL SHOWS A VERY SLIGHT INCREASE INTO SUNDAY BUT A TREND FOR SLOWLY DECREASING SWELL AS THE RIDGE AXIS SAGS SWD MON THRU WED. THE MIDDAY OBSERVATIONS FROM TYBG1 AND SPAG1 HAD SEAS BETWEEN 5 AND 6 FT SO WILL CONTINUE MARGINAL SCA FOR SEAS IN OUR GEORGIA 20-60 NM WATERS TONIGHT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...SMALL CRAFT ADVISORY AMZ374. SC...NONE. && $$ 23/24 sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 135 PM EDT SAT MAY 15 2004 .UPDATE FOR AVIATION... .DISCUSSION... 1050 AM EDT SAT MAY 15 2004 FRONT JUST THRU PARKERSBURG AT 10 AM. NEW ETA AND RUC MODELS SHOW THIS FRONT ONLY VERY SLOWLY DRIFTING EAST THROUGH MID AFTERNOON... THEN PUSH EAST A LITTLE FASTER LATER THIS AFTERNOON BEHIND A SURFACE WAVE RIPPLING NORTHEASTWARD ALONG THE FRONT. THUS...SOME MAJOR CHANGES IN THE FORECAST THIS AFTERNOON EAST OF THE OHIO RIVER. WILL RAISE TEMPERATURES 3 TO 5 DEGREES DUE TO CLOUDS MOSTLY BEHIND THE FRONT...AND WILL KEEP POPS IN THE CHANCE CATEGORY FOR MUCH OF THE AFTERNOON. WILL HAVE TO WATCH THE POSSIBILITY OF TRAINING ECHOES WITH LOCALLY HEAVY RAIN ACROSS WESTERN AREAS THIS AFTERNOON DUE TO SLOW MOVEMENT OF THE FRONT. JMV && .PREVIOUS DISCUSSION... 359 AM EDT SAT MAY 15 2004 .SHORT TERM...THROUGH SUNDAY. WEAKENING COLD FRONT MOVES INTO FORECAST AREA TODAY THEN STALLS WITHIN FORECAST AREA TONIGHT...ON A SOUTHWEST TO NORTHEAST LINE. ON SUNDAY...THIS FRONT MAY TAKE ON A MORE WEST TO EAST ORIENTATION BUT CANNOT IMAGINE A FRONT THIS WEAK MAKING MUCH SOUTHWARD HEADWAY DURING THE DAY THIS TIME OF YEAR. A PAIR OF WEAK UPPER LEVEL SHORT WAVES MOVES THROUGH THE SOUTHWEST FLOW. THE FIRST PUSHES RAIN INTO THE ARA THIS MORNING...THE SECOND MAY ACTUALLY RE-INVIGORATE IT A BIT LATE TODAY WHILE GIVING THE FRONT ONE MORE NUDGE EASTWARD. THUNDERSTORM POTENTIAL TODAY IS LIMITED BY LACK OF SHEAR OR UPPER SUPPORT. THERE IS JUST ENOUGH INSTABILITY OWING LARGELY TO HIGH PWS (1.5-1.7) TO SUPPORT SOME THUNDER. FRONT STILL LAYS ACROSS AREA SUNDAY BUT UPPER SUPPORT IS GONE...EVEN NEGATIVE. ATMOSPHERE DOES BECOME UNSTABLE AGAIN DURING THE AFTERNOON THOUGH. THIS MAY ESPECIALLY BE THE CASE NORTH WHERE THERE IS THE MOST SUNSHINE. OPTED TO EXCLUDE THUNDER FROM LATE TONIGHT THROUGH EARLY SUNDAY. THIS IS LARGELY AN EXTRAPOLATION OF WHAT IS OCCURRING NOW...FRONT/UPPER SUPPORT SHOULD BE EVEN WEAKER. ANY SUNSHINE AT ALL FIRST THING THIS MORNING WILL TAKE US ABOVE MAV FOR HIGHS TODAY SO ABOVE MOST SITES. USED A BLEND TONIGHT AND SUNDAY. .LONG TERM...SUNDAY NIGHT AND BEYOND. WEAK UPSLOPE FLOW AND HIGHER BL RH LINGERS THE FIRST HALF SUNDAY NIGHT...SO CARRIED SCHC/CHC POPS FOR EXTREME EASTERN ZONES...WHILE BOOSTING SKY COVER. THE START OF THE NEW WORK WEEK BRINGS H5 RIDGE BACK INTO THE PICTURE WITH INCREASING HEIGHTS AND TEMPS ALOFT. ETA/GFS DIFFER IN STRENGTH OF MID LEVEL WAVE RUNNING THE RIDGE FROM THE SOUTHWEST MONDAY. GFS STRENGTHENS FEATURE AS IT HEADS TOWARD THE OH VALLEY...WHILE THE ETA MAINTAINS SAME LEVEL OF INTENSITY. THIS CAUSES TRICKLE DOWN EFFECTS AS THE GFS BRINGS A NICE POCKET OF H2 UPR LVL DIV THROUGH DURING THE PEAK HEATING HOURS...CREATING GREATER AREAL COVERAGE OF TRW...WHILE ETA CONFINES QPF E OF OH RIVER. NOT TOTALLY SOLD ON GFS SOLUTION...BUT WON'T COMPLETELY DISCARD SINCE ITS NOT GRID SCALE FEEDBACK...HOWEVER PER THE PROFUSE AMOUNT OF MSTR...EXPANDED CHC POPS TO ENTIRE CWA. REMAINING PART OF THE WEEK HINGES ON THE WHEREABOUTS OF THE BAROCLINIC ZONE...WHICH BECOMES STATIONARY WEDNESDAY. H5 RIDGE WEAKENS ALLOWING WESTERLIES TO COLLAPSES INTO THE LOWER GREAT LAKES DAY 4...WHILE THE CLOSE PROXIMITY OF HIGH PRESSURE BEHIND IT...WINDS IN THE COLD SECTOR BECOME EASTERLY...THUS HALTING SOUTHWARD ADVANCEMENT. GFS DROPS FRONT THROUGH WED...HOWEVER GIVEN RECENT TRENDS...EXPECT LATER MODELS TO RETARD SOUTHWARD PROGRESSION. THAT IN MIND...CWA REMAINS IN WARM SECTOR WITH INCREASING INSTABILITY EACH SUCCESSIVE DAY. LI/S FALL TO -4C WITH SBCAPES ECLIPSING 1.5KJ/KG TUES - THUR...NOT TO MENTION HIGH H8 DWPTS AND WARM CLOUD DEPTH. DYNAMICS RESIDE ALONG THE FRONT...SO NOT CONCERNED WITH SVR WX POTENTIAL AS I AM HIGH WATER THREAT PER TRAINING PATTERN ESTABLISHING. LITTLE TO ANY CHANGES DONE TO EXISTING MAX/MIN T GRIDS DURING THIS PERIOD. TRM/29 && .AVIATION... 135 PM EDT SAT MAY 15 2004 NOT A GOOD AVIATION TIME PERIOD. THUNDERSTORMS A THREAT THIS AFTERNOON AT ALL LOCATIONS...ESPECIALLY IN THE WEST BEFORE 21Z AND IN THE EAST AFTER 21Z. ALL THIS AHEAD OF A COLD FRONT AT 1 PM LOCATED JUST EAST OF THE OHIO RIVER. FRONT WILL MOVE SLOWLY EASTWARD THIS AFTERNOON...REACHING THE MOUNTAINS AROUND 00Z THIS EVENING. THE FRONT WILL THEN HANG UP IN THE MOUNTAINS TONIGHT AND SUNDAY MORNING BEFORE WASHING OUT. LOOK FOR MVFR CONDITIONS IN CLOUDS AND VISIBILITY WITH SOME RAIN SHOWERS BEHIND THE FRONT THIS AFTERNOON AND EVENING...BECOMING IFR ALL LOCATIONS EARLY TONIGHT AS THE WINDS DROP OFF AND THE LOW LEVEL MOISTURE HANGS ON. CONDITIONS IMPROVE ONLY SLOWLY SUNDAY MORNING AS HIGH PRESSURE TRIES TO BUILD IN. JMV && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. VA...NONE. KY...NONE. OH...NONE. && $$ wv