WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL 944 AM EDT TUE APR 4 2000 PRE-FRONTAL TROUGH AND AXIS OF LOW LEVEL CONVERGENCE NOTED ON MAPS STREAMLINE ANALYSIS ALONG WITH JUST ENOUGH MOISTURE AND INSTABILITY IS HELPING TO MAINTAIN A SOLID LINE OF SHOWERS FROM JUST SOUTH OF KJAX EXTENDING SOUTHWEST TO KOCF...THEN CONTINUING SOUTHWEST TO NEW PORT RICHEY AND EXTENDING OVER THE ADJACENT GULF WATERS WEST AND SOUTHWEST OF TAMPA FOR MORE THAN 75NM. RETURNS FOR 88DS INDICATE THAT THIS LINE IS MOVING SEWD AT AROUND 20 KNOTS...AND SHOULD BEGIN AFFECTING MUCH OF MY CENTRAL ZONES DURING THE NEXT HOUR OR TWO AS IT CONTINUES MOVING SEWD...MOVING INTO AND AFFECTING MY SOUTHERN MOST ZONES BY EARLY THIS AFTERNOON. WITH THIS LINE BEING SO NARROW...THE RAINFALL SHOULD BE SHORT-LIVED WITH LIGHT AMOUNTS EXPECTED. IN ADDITION TO THE PRE-FRONTAL TROUGH PRECIP...SECONDARY LINE OF SHOWERS WAS ALSO BEING DETECTED BY 88DS NEAR A KTLH TO KAQQ LINE ASSOCIATED WITH MAIN FRONT. THIS LINE SHOULD ALSO CONTINUE MOVING SEWD AND WITH MESO-ETA AND RUC INDICATING FAIRLY DECENT PVA COMING ACROSS THIS AFTERNOON AND AREA IN RRQ OF STRONG UPPER LEVEL H20 JET...PLAN TO KEEP MENTION OF PRECIP GOING IN ALL ZONES FOR THE AFTERNOON HOURS...ALBEIT LOW POPS. AS FAR AS THUNDERSTORMS GO...THICK CLOUD COVER TO THE NORTH WILL KEEP HEATING DOWN SO TSTM DVLPMT THERE LOOKS LOW...BUT WITH BETTER HEATING TAKING PLACE ACROSS PORTIONS OF MY CENTRAL AND SOUTHERN ZONES AT THE MOMENT WILL KEEP MENTION OF ISOLATED TSTMS IN THESE AREAS THIS AFTERNOON. MARINE...C-MAN AND OFFSHORE BUOY NOW INDICATING SCEC WIND AND SEA STATES. UPSTREAM BUOY 42039 SOUTH OF PANAMA CITY NOW INDICATING NW WINDS SUSTAINED AT 22 KNOTS WITH GUSTS TO 29. AS THE FRONT CONTINUES MOVING SOUTH WINDS WILL SHIFT TO THE NW AND INCREASE..SO WILL UP SCEC TO SCA FOR ALL MARINE LEGS IN THE 1030 AM UPDATE...OTHERWISE NO OTHER SIGNIFICANT CHANGES ARE PLANNED. .TBW...SCA BONITA BEACH TO SUWANNEE RIVER INCLUDING TAMPA BAY THIS AFTERNOON. FIRE WEATHER WATCH ALL ZONES ON WEDNESDAY. MCMICHAEL fl EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 923 AM EDT TUE APR 4 2000 CURRENTLY/TODAY...A NARROW BAND OF SHOWERS...WHICH WAS MOVING EAST AT 20 MPH ACROSS NORTHEAST FLORIDA AND EASTERN GULF...WAS APPROACHING NORTHERN SECTIONS. THESE SHOWERS WERE OCCURRING JUST AHEAD OF A COLD FRONT THAT WAS MOVING ACROSS THE PANHANDLE. LATEST RUC MODEL INDICATES MAIN UPPER DIVERGENCE WAS STARTING TO PULL OUT TO THE NORTH WHICH SEEMS TO BE SUPPORTED BY LATEST SATELLITE LOOPS. ATMOSPHERE OUT AHEAD OF THE LINE CONTINUED DRY IN THE MID LEVELS WITH TEMPS ALOFT NOT VERY COOL. 10Z CANAVERAL SOUNDING EXHIBITED A CAP OF ABOUT 3 DEGREES CELSIUS AROUND 825 MB. INCREASE IN DEEP MOISTURE WAS ACTUALLY LAGGING THE WEAK PRE FRONTAL CONVECTION. THEREFORE...EVEN WITH DAYTIME HEATING...INSTABILITY PRECEDING THE THIN BAND OF SHOWERS IS NOT EXPECTED TO INCREASE SIGNIFICANTLY. FOR A MORNING UPDATE...PLAN TO ADJUST TIMING OF SHOWER CHANCE ACROSS THE NORTH HALF OF THE AREA. MAY HAVE TO TREND MAX TEMPS BACK SLIGHTLY ALSO SINCE CLOUDINESS BEHIND WEAK SHOWER BAND SHOULD INHIBIT HEATING BEFORE COLD FRONT PUSHES THROUGH IN THE EARLY AFTERNOON. WITH HEATING INTO THE MID 80S IN THE SOUTH...WILL LEAVE A MENTION OF POSSIBLE THUNDERSTORMS. MARINE...WINDS WERE MEETING ADVISORY CRITERIA BUT SEAS WERE LAGGING DUE TO OFFSHORE FLOW. AT THIS POINT WILL NOT CHANGE THINGS MUCH SINCE THE TREND IS FOR INCREASING WINDS. SEAS WILL ALSO LIKELY BE HIGHER IN THE VICINITY OF PASSING SQUALLS. .MLB...SCA FLAGLER BEACH TO COCOA BEACH. FIRE WEATHER WATCH FOR ALL OF EAST CENTRAL FLORIDA WED. AVIATION/FIRE WX...KELLY PUBLIC/MARINE....LASCODY fl SOUTHWEST IDAHO/SOUTHEAST OREGON AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BOISE IDAHO 930 AM MDT TUE APR 04 2000 UPDATED FOR THERMAL RDG/SFC TROF TIMING...WARMER TEMPS AHEAD OF IT....AND FOR BIT MORE WIND WITH FRONT THIS EVENING AND TONIGHT WITH BUILDING HIGH PRES /11MB RISES IN 12HRS CENTERED ON 6Z/ OVERNIGHT. MESO ETA AND RUC SHOW THERMAL PACKING AND SFC PRES TROF ABOUT 14Z WITH COLD FRONT FROM NEAR OMAK WA TO WRN COLUMBIA BASIN TO NEAR REDMOND ORE. BY 18Z RUC/MESOETA BRING CDFNT TO MLP-LGD-SWWRD WITH THERMAL RDG TO NEAR BKE-REO THEN MESOETA BRINGS THERMAL RDG THROUGH ONO-BOI EARLY TO MID AFTERNOON AND THROUGH TWF BY MID-LATE AFTN. CDFNT AT 21Z/3PM EXPECTED TO NEAR MCCALL AND ONTARIO WITH FRONT TO CALDWELL AND BOISE ABOUT 6PM. WINDS SHIFT FROM SE TO SW WITH THERMAL RDG/SFC PRES TROF THEN TO BREEZY NW WINDS WITH FRONTAL PASSAGE AND BUILDING HIGH PRES THIS EVENING AND OVERNIGHT. .BOI...NONE. id AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 242 PM CDT TUE APR 4 2000 MAIN FCST PROBLEMS TODAY ARE AS FOLLOWS: 1. COVERAGE AND INTENSITY OF FROST ACROSS FORECAST AREA TONIGHT. 2. WIND ON WEDNESDAY 3. MARGINAL CHC OF PCPN IN SERN PTN OF CWA ON THU. DECENT COLD AIR ADVECTION CU AND MIXED PCPN NOTED ACROSS ERN PTN OF FORECAST AREA SINCE 15Z. MOST SIGNIFICANT PCPN THREAT MOVING EAST OF FORECAST AREA AS OF 19Z...AHEAD OF 50H VORT AXIS/LOW LEVEL THERMAL TROF CLOSELY PROGGED BY 12Z RUC/AVN NUMERICAL MODELS TODAY. ANTICPATE DE-COUPLING OF WINDS ACRS FORECAST AREA BETWEEN 01Z-02Z WITH NEAR CALM WINDS EXPECTED CLOSER TO MIDNIGHT. BIGGEST CONCERN IS TIMING OF RETURN WAA INTO SERN MO/SWRN IL/WRN KY LATE TONIGHT AND ANY MINOR CI CLOUD COVER ALOFT. ALTHOUGH PAH FORECAST AREA IS PRONE TO RAPID DE-COUPLING OF WINDS...WIND SPEEDS MAY NOT DIP LOW THIS EVENING TO ALLOW FOR STRONG THERMAL STRATIFICATION /INVERSION/ TO TAKE A STRONG HOLD UNTIL MIDNIGHT. COORD WITH AREA USDA OFFICES INDICATE THAT APPLE AND SOME PEACH BLOOMS MAY BE SUSCEPTIBLE TO FROST DAMAGE...GIVEN IDEA TEMP CONDITIONS. NOT PARTICULARILY CONCERNED WITH WIDESPREAD TEMPS AOB 28 DEGREES FOR FREEZE WARNING POTENTIAL...BUT AM CONCERNED WITH POTENTIAL FOR WIDESPREAD FROST. EVEN THOUGH IT IS STILL EARLY IN THE GROWING SEASON...DECIDED TO ISSUE FROST ADVISORY CWA-WIDE...MAINLY AS A PRECAUTIONARY MEASURE FOR FRUIT GROWERS AND THOSE PERSONS PLANTING TENDER FLOWERING PLANTS. AS THE INVERSION BREAKS UP AROUND SUNRISE ON WED...SFC GRADIENT INCREASES SHARPLY IN ADVANCE OF DEVELOPING FRONTAL BOUNDARY ACROSS THE UPPER AND CENTRAL PLAINS IN FLATTENING UPPER RIDGE. SFC GRADIENT SHOULD RELAX SOMEWHAT LATER ON WED NIGHT. THE FRONTAL BOUNDARY IS PROGGED TO SLOW DOWN AND BECOME DIFFUSE ACRS CWA BY 18Z THU. BIGGEST CONCERN IS THAT LOW TO MID 50 DWPTS AND 0 TO -3 LI S ARE PROGGED ACRS EXTREME SRN KY JUST AHEAD OF THE FRONTAL BOUNDARY. AFTER COORD DISC WITH BNA...DECIDED TO KEEP FCST DRY FOR THU. BEST CHANCE OF RAIN IN EXTENDED STILL APPEARS TO BE FRI NITE INTO SAT AM. NEAR NORMAL TEMPERATURES AND DRY CONDITIONS SHOULD PREVAIL ON SUN. .PAH...MAINTAIN FROST ADVISORY TONIGHT FOR ENTIRE WFO PADUCAH FORECAST AREA. SMITH ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 945 PM EST TUE APR 04 2000 FEW SPRINKLES/FLURRIES BEING GENERATED OVR NW PTN OF FA AS STG VORT MX AND COLD POOL APPCH THE AREA. MESO ETA AND RUC SHOW RH QUICKLY RETREATING NWD IN NXT FEW HRS SO ANY PCPN WL BE SHORT LIVED AND CONFINED TO FAR NW. NW WNDS WERE QUITE STG BHND FNT THIS EVE SO WL BEEF THEM UP TO 15 TO 25 MPH IN ZONES. MARINE FCSTR ALSO RAISING WNDSPDS OVR THE BAY IN CWF. TEMPS AND DWPTS HV BN FALLING STEADILY THIS EVE. DWPTS WERE ALREADY NR 30 DEGS AT 01Z AND WERE RUNNING CLOSE TO 10 DEGS BLO MOS VALUES. GIVEN STRENGTH OF CAA...PLAN TO HILITE LOW PTN OF TEMP RANGES OVERNGT. NO CHGS TO RMNDR OF FCST. .LWX...SCA MD PTN CHES BAY AND TIDAL POTOMAC. ARTHUR md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1048 PM EDT TUE APR 4 2000 MAIN FORECAST CONCERN OVERNIGHT WILL BE WITH CLOUD COVER. CURRENTLY...SFC ANALYSIS SHOWS RIDGE AXIS ACROSS WI AND WESTERN UPPER MI...WITH CYCLONIC FLOW WEAKENING ACROSS ERN UPR/NRN LWR MI. INCREASED SUBSIDENCE/DRYING HAS SCOURED OUT THE CLOUD COVER ACROSS THE SW PORTION OF NRN LWR MI. HOWEVER...WITH 850 MB TEMPS AROUND -13C PER 00Z KAPX RAOB...LAKE CLOUDS ARE HANGING TOUGH ACROSS ERN UPR AND THE NE HALF OF NRN LWR MI WITH THE NW FLOW (WITH THE BACK EDGE ALONG THE -12C ISOTHERM). 00Z RAOBS AND RUC MODEL OUTPUT ARE CONSISTENT WITH 12Z PROGS... WITH THE INCREASED UPPER CONVERGENCE/RIDGING AND SUBSIDENCE ARRIVING AS PLANNED. HOWEVER...THINK THE LAKE CLOUDS WILL HOLD TOGETHER FOR A WHILE OVERNIGHT UNTIL (AT LEAST) THE PASSAGE OF THE 925-850 MB THERMAL TROUGHS. EVEN THEN...LAKE CLOUDS ARE TRADITIONALLY TOUGH TO SCOUR OUT AT NIGHT (WITHOUT THE BENEFIT OF DAYTIME MIXING) DESPITE INCREASED RIDGING/ANTI-CYCLONIC FLOW. IN FACT...IF ANYTHING THE STRENGTHENING SUBSIDENCE INVERSION MAY ACT TO TRAP THESE CLOUDS FURTHER...WHICH IS OFTEN THE CASE AS LONG AS THERE IS SUFFICIENT LAKE HEAT/MOISTURE FLUX UNDERNEATH INVERSION BASE (WHICH THERE WILL BE TONIGHT) BASED ON THE LATEST (00Z) MESO-ETA SOUNDINGS...IT APPEARS NW BOUNDARY LAYER WINDS AND LAKE-INDUCED MOISTURE AROUND 850 MB WILL HOLD ON FOR MUCH OF THE NIGHT (THROUGH 09Z OR 5 AM) ACROSS EASTERN UPPER AND FAR NE LWR MI. AFTERWARDS...MORE DEFINITIVE WARM ADVECTION/WIND SHEAR WITHIN THE LOWER LEVELS IS NOTED...WHICH WILL DIMINISH THESE LAKE CLOUDS RAPIDLY. SO...WILL WORD MOSTLY CLOUDY IN THESE AREAS...PARTLY CLOUDY ELSEWHERE. IN ADDITION...WILL LIKELY BOOST LOW TEMPS IN AREAS WHERE THE MORE EXTENSIVE CLOUD COVER IS EXPECTED TO LINGER. THANKS TO MQT FOR THE COORDINATION. FORECAST UPDATE WILL BE OUT BY 11 PM. .APX...NONE. HURLEY mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 930 PM EDT TUE APR 4 2000 WILL UPDATE THE FORECAST AND REMOVE THE SNOW SHOWER WORDING AS RADAR TRENDS SHOW THAT THE SNOW SHOWERS CONTINUE TO WEAKEN AND ARE NEARLY GONE. FORECAST SOUNDINGS FROM THE RUC SHOW THE 7000 FT MOISTURE PULLING OFF TO THE EAST RATHER QUICKLY TONIGHT...THUS THE CLEARING WORDING WILL WORK FINE. FORECAST LOWS WILL BE A TOUGH CALL. AM EXPECTING THE WINDS TO DIMINISH. AFTER LOOKING DEWPOINTS...WILL INTRODUCE SOME UPPER TEENS TO THE FORECAST...MAINLY FOR MY NORTHEAST COUNTIES. LANSING COULD HIT THE UPPER TEENS AS WELL. ELSEWHERE...AM EXPECTING MOST PLACES TO FALL INTO THE LOW 20S...BUT A FEW MID 20S ARE POSSIBLE NEAR THE SHORE. .GRR...NONE. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 255 PM EDT TUE APR 4 2000 CLOUDS IN PLACE ACROSS LOWER MICHIGAN AT THIS TIME...BEING AIDED BY UPPER TROF...LAKE ENHANCEMENT AND DIURNAL COMPONENT. SOME SCATTERED SNOW SHOWERS ARE OCCURRING AS WELL DOWNWIND OF LAKE MICHIGAN. RIDGING BOTH AT THE SFC AND ALOFT IS NOTED TO THE WEST OF THE GREAT LAKES ACROSS THE NORTHERN PLAINS. FAIRLY PROGRESSIVE PATTERN IS PLACE ACROSS THE CONUS DURING THE SHORT TERM WITH THE UPPER TROF CURRENTLY OVERHEAD BEING KICKED OUT...WHICH IS QUICKLY REPLACED BY THE NORTHERN PLAINS RIDGING FOR TOMORROW. UPPER SHORTWAVE SEEN IN THE WATER VAPOR IMAGERY OVER THE PACIFIC NORTHWEST IS THE NEXT WEATHER MAKER FOR WEDNESDAY NIGHT. FCST CONCERNS ARE CLOUD RELATED TONIGHT AND WEDNESDAY...PCPN RELATED WED NIGHT...AND CLOUDS AGAIN ON THURSDAY. FOR TONIGHT...BREAKS IN THE OVERCAST ALREADY SHOWING UP ACROSS LAKE MICHIGAN AT 18Z...AND THIS TREND SHOULD CONTINUE ACROSS THE FORECAST AREA TONIGHT. UPPER TROF MOVES EAST TONIGHT...WITH RIDGING BUILDING IN AT ALL LEVELS. RIDGING SHOULD AID IN CLEARING SKIES OVERNIGHT. RUC MODEL DATA SHOWING RH AT 925 AND 850MB/S DRYING UP QUITE A BIT THIS EVENING AHEAD OF THE ETA WHICH CLEARS THINGS LATER TONIGHT. IN ANY EVENT...CLEARING IS MENTIONED IN THE CURRENT ZONES FOR TONIGHT...AND WILL LEAVE THAT WORDING. WILL MENTION SCATTERED EVENING SNOW SHOWERS AS WELL. AS FOR LOWS...WILL STICK WITH GOING FCST OF MID 20S LAKESHORE...LOW 20S INLAND. FOR WEDNESDAY...CLOUDS WILL BE ON THE INCREASE AHEAD OF THE APPROACHING SHORTWAVE...AND WILL WORD THE FCST THAT WAY. HIGH CLOUDS SHOULD BE ON THE INCREASE DURING THE MORNING...WITH SOME CU POSSIBLE...THEN MID CLOUDS ADVECT IN TOWARD MIDDAY INTO THE AFTERNOON. WARM AIR ADVECTION WILL BE OFFSET SOME BY THE INCREASING CLOUDS AND A WIND OFF THE LAKE...SO WILL STAY NEAR MOS NUMBERS OF AROUND 50 TO THE LOWER 50S. WEDNESDAY NIGHT...COLD FRONT PROGRESSES THROUGH THE FCST AREA ASSOCIATED WITH THE AFOREMENTIONED PACIFIC NORTHWEST SHORTWAVE. QUESTION IS HOW HIGH TO TAKE THE POPS. BEST DYNAMICS ARE TO THE NORTH ASSOCIATED WITH THE VORT CENTER AND LEFT EXIT REGION OF THE 300MB JET STREAK. MOISTURE IS ALSO A LIMITING FACTOR AS A SFC HIGH ALONG THE GULF COAST BLOCKS MUCH IN THE WAY OF MOISTURE RETURN. GOOD CONVERGENCE ALONG THE FRONT IN THE LOWER TROP COMBINED WITH SOME SYNOPTIC SCALE LIFT PRESENT VIA DPVA AND WAA...WILL NECESSITATE CHANCE POPS TO COVER THE SHOWER THREAT. LOWS AROUND 40 SHOULD WORK. ON THURSDAY...RIDGING BUILDS INTO THE REGION IN THE WAKE OF THE COLD FRONT...SO WILL WORD THE FCST AS BECOMING PARTLY CLOUDY. SHOWERS SHOULD BE EAST OF THE FCST AREA BY DAYBREAK. DUKESHERER .EXTENDED FORECAST DISCUSSION... WEAK LONGWAVE RIDGING THURSDAY NIGHT WILL KEEP CONDITIONS DRY UNDER PARTLY CLOUDY SKIES...BUT WILL GIVE WAY TO AN APPROACHING SHORTWAVE EXPECTED TO ARRIVE ON FRIDAY. PREFRONTAL PCPN COULD BEGIN AS EARLY AS 13Z FRIDAY IF MRF VERIFIES. LOOKS LIKE WARM FRONT WILL PUSH THROUGH LOWER MICHIGAN BY LATE AFTERNOON AND THE COLD FRONT OVERNIGHT INTO SATURDAY MORNING. SFC LOW TRACK WILL MARCH THROUGH CENTRAL SECTIONS OF LOWER MICHIGAN AND HAS SIGNATURES CONDUCIVE TO THUNDERSTORM DEVELOPMENT...INCLUDING THE SYSTEMS PATH THROUGH FA...TIGHT PRESSURE GRADIENT...STRONG 850MB TEMP GRADIENT...AND STRONG UPPER DYNAMICS. THIS WILL NEED CLOSE WATCHING. SYSTEM SHOULD BE EAST OF FORECAST AREA BY SATURDAY NIGHT ALTHOUGH A QUICK MOVING CLIPPER WILL DROP INTO LOWER MICHIGAN BY SUNDAY AFTERNOON CONTINUING CLOUDY CONDITIONS AND A CHANCE OF PCPN. ALTHOUGH A LITTLE FAR OUT TO BE SURE MRF CRITICAL THICKNESS VALUES DO BORDER A FROZEN PCPN POSSIBILITY...BUT AT THIS POINT WILL ONLY MENTION SHOWERS. MCINERNEY .GRR...NONE. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1150 AM EDT TUE APR 4 2000 MAIN FCST CONCERNS ARE LINGERING LGT SN AND CLOUD TRENDS ATTM MOST OF UPR MI STILL UNDER INFLUENCE OF CYCLONIC FLW FM 992MB SFC LOW OVR SRN QUEBEC. CYC FLW IN ADDITION TO LIFT PROVIDED BY UPR LEV SHRTWV OVR ERN UPR MI PER WV LOOP AND CAA PROD LK DLT T/S AROUND 14 C HAVE HELPED TO SUSTAIN LGT SN AND FLURRIES ACROSS MUCH OF UPR MI THIS MORNING. 15Z VIS SAT SHOWING BACK EDGE OF MVFR CIGS FM CYQT TO ASX AS RIDGE AXIS IS BEGINNING TO BUILD IN FM SRN PLAINS. COMPARING 12Z RAOBS TO THERMAL PROGS IT APPEARS RUC INITIALIZED THE BEST AS 06Z ETA WAS NOT SOUTH/EAST ENOUGH WITH CAA TOUNGUE AS GRB H8 TEMP WAS -11 C. WITH LINGERING H8-H7 LAYER OF Q-VECTOR CONVERGENCE CLEARING MOST OF FA BY 21Z PER RUC AND 06Z ETA...BELIEVE SNOW SHOWERS OVR W FA PER ONTONAGON OB...SPOTTER REPORT NEAR KENTON...AND 88D REFL WL BEGIN TO WANE WITH INCREASING SUBSIDENCE BEHIND SHRTWV AND BUILDING RIDGE. ALSO IN WEST EXPECT INCREASING SUNSHINE AS FORCING MOVES OUT AND HIGHER SUN ANGLE PUNCHES HOLES IN FAIRLY SHALLOW DECK...AS VIS SAT IS ALREADY SHOWING. ACROSS CNTRAL AND ERN FA SN SHOULD HANG ON FOR MUCH OF DAY AS THERMAL TROF AND CYCLONIC FLW LINGERS. ADDED LESS THAN AN INCH WORDING FOR EAST AS BEST OVR WATER FETCH AND FORCING REMAINS. SOME LES ENHANCEMENT LOOKS TO BE TAKING PLACE PER 88D REFL BANDING SIG OVR ALG COUNTY ATTM. TEMPS ALSO BUMPED DOWN A BIT UNDER MOSTLY CLOUDY SKIES WITH LESS CHANCE OF SUSTAINED SUNSHINE. WINDS CONTINUE TO SLACKEN FM WEST TO EAST REMAINDER OF AFTN AS PRESSURE GRADIENT RELAXES AS SFC RIDGING TAKES OVR. 06Z ETA BLYR WIND DECREASES TO 15KT BY 18Z FAR WEST AND BY 21Z CNTRAL. MORNING SFC OBS FM IWD...ONT...AND CMX ALSO SHOW CONSTANT DIMINISHING TREND AS WELL. .MQT...NONE. JLA mi SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BILLINGS MT 932 AM MDT TUE APR 04 2000 .TDY AND WED... 12Z ANALYSIS SHOWS 700MB A LITTLE WARMER THAN EXPECTED AND SHERIDAN ALREADY 63 DEGREES. LOOKING AT 12Z RUNS...RUC HAS WARMER TEMPERATURES THAN ETA WHICH HAS RUN A LITTLE COOL AS OF LATE. +18 DEGREES AT 850 MB AND +3 AT 700 MB ON RUC INDICATE THAT TEMPERATURES WILL HAVE A CHANCE TO THREATEN RECORDS AT BILLINGS AND SHERIDAN. STILL EVALUATING WIND POTENTIAL FOR TONIGHTS EVENT. RUC IS SLOWER AND DEEPER THAN ETA RUN SO WILL WAIT FOR AVN TO SEE HOW THINGS ARE LINING UP. WILL ISSUE UPDATE FOR POTENTIAL RECORD HIGHS. BORSUM .THU...FRI...AND SAT... ANOTHER STRONG SHORTWAVE WILL TRACK ACROSS MONTANA THURSDAY. SHORTWAVE WILL TAP INTO SOME INSTABIBILITY...SO THE CHANCE OF SHOWERS FORECAST STILL LOOKS GOOD. UPPER LEVEL RIDGE WILL BUILD INTO THE NORTHERN ROCKIES FRIDAY AND SATURDAY...BRINGING DRY WEATHER AND WARMER TEMPERATURES. MEDIUM RANGE MODELS ARE AGREEABLE THIS MORNING ON THE CURRENT FORECAST PACKAGE. NO CHANGES TO THIS MORNINGS EXTENDED FORECAST PACKAGE. MIDDENDORF BIL NNWBB /075 038/054 028/046 030/051 037/065 59032 61 LVM NBWBB /074 034/054 030/048 033/052 035/063 59042 61 HDN NNWBB /076 037/054 029/047 030/052 033/066 59032 61 MLS BNWEB /073 038/054 026/045 028/049 030/063 59044 61 4BQ BNWEB /072 038/054 026/045 029/049 031/063 59033 61 BHK BNWEB /071 037/054 025/044 026/048 029/062 59044 61 SHR BNWBB /075 035/054 027/047 028/053 033/065 59033 61 mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 110 PM EDT TUE APR 4 2000 SOLID (BUT NARROW) LN OF SHRA FEEDING OFF POCKET OF INSTABILITY ALONG THE PRE-FNTL TROF OFF THE COAST. THIS LN IS MOVING AWAY FROM ILM/S WATERS W/ NO EFFECT HERE. MEANWHILE AHEAD OF THE FRONT...A POORLY ORGANIZED LINE OF SHRA IS SLOWLY MOVING EWD ACROSS WRN CWFA WHERE BETTER CAPPING AND MORE STABLE AMS IS APPARENT. ALTHOUGH WE ARE NOT EXPECTING MUCH FROM THIS...PLAN ON HOLDING ONTO SLIGHT CHANCE FOR THE EARLY EVENING...THEN CLEARING FOR THE REMAINDER OF THE 1ST PD. SVR THREAT HAS ABATED...PER EARLIER SPC DISCUSSION. STRONGER WINDS STILL SHOWING UP IN THE LATEST LAMP PROJECTIONS AND PARTIALLY THE RUC...HOWEVER AMOUNT OF CLD COVER HAS LIMITED THE AMOUNT OF MIXING. STILL EXPECTING BREEZY CONDITIONS FOR THE REMAINDER OF THE AFTERNOON W/ DECENT PRES GRAD. SUBSIDENCE TO INCREASE OVER THE NXT 24H ON THE HEELS OF UPPER TROF AXIS SWEEPING THROUGH OVERNIGHT. COULD BE SOME RESIDUAL 50-60% RHS IN THE 850-925MB LYR ON WED...SO FEW CU POSSIBLE BUT OVERALL SUNNY SKIES PREVALENT...ESP W/ DOWNSLOPE WIND COMPONENT. CAA TONIGHT WILL EASE TEMPS INTO THE LOWER 40S AND ONLY MID 60S WED. HOWEVER...LLVL THICKNESSES REBOUND NICELY WED NIGHT/THU W/ 77-79 DEG READINGS EXPECTED THU. IN THE EXTENDED WILL INCLUDE CHANCE SHOWERS/TSTMS FOR SUN W/ NEXT SIGNIFICANT S/WV TO APPROACH. CWF: MARINE STATIONS REPORTING 8 FT SEAS W/ WINDS VARYING IN AND OUT OF SCA CRITERIA. STRONGER WIND FIELD NE OF HERE. WILL KEEP SCA IN PLACE FOR TONIGHT W/ LLVL CAA SPREADING ACROSS THE WATERS. SPEEDS WILL DIMINISH ON WED AS CAA AND PRES GRAD WANE. PRELIMINARY CCF: ILM UU 043/065 043/077 055 29200 FLO UU 041/066 041/078 053 29100 MYR UU 045/065 043/074 056 29200 .ILM...SMALL CRAFT ADVISORY SURF CITY NC TO SOUTH SANTEE RIVER SC. PFAFF nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 947 AM EDT TUE APR 4 2000 12Z SFC ANALYSIS SHOWS CDFNT STRETCHING FROM CNTL VA THRU WRN NC PIEDMONT TO SC UPSTATE. PRE-FNTL TROF CROSSING CNTL CWFA ATTM. 88D SHOWS SCT-NUMEROUS RW MAINLY OVER WRN/NWRN CWFA. 88D MOSAIC SHOWS SOLID BAND OF LGT/MOD RAIN JUST AHEAD OF THE FNT. 06Z MESO-ETA TRENDS CONTINUE ALONG SAME LINES AS PREVIOUS MODEL RUNS CARRYING THE FNT PAST THE AREA LATE THIS AFTN INTO EVE. BEST SUPPORT ARRIVES AFTER LO- LVL MOISTURE BEGINS DIMINISHING. BEST THETA-E RIDGE REMAINS OFFSHORE. THREAT OF SVR WX APPEARS TO BE DIMINISHING LATE THIS MRNG INTO AFTN. 12Z MHX RAOB & KLTX VWP SHOW STRONG UNIDIRECTIONAL LO-LVL WINDS W/ 50KT AROUND 5K FEET & 30-40 JUST OFF THE SFC. BUT VWP 1K WINDS HAVE DECREASED SOME W/ SHIFT TO A MORE WRLY DIRECTION AS TROF NEARS. CHS NOT TOO FAR BEHIND. MAIN LIMITING FACTOR IS LACK OF INSTABILITY AS THICK CLOUD COVER SHOULD PERSIST THRU THE AFTN CHOKING OFF GOOD INSOLATION. MODIFIED MORNING SOUNDINGS SHOW 30+ K INDICES & 40+ TT BUT MARGINAL LI/S AT BEST & WEAK CAPES (<1K). WILL BASE POPS ON STATUS OF RAIN LINE AT 15Z BUT AM INCLINED TO RAISE AT THIS POINT. LAMP GUIDANCE IS BELOW FCST TEMPS & CLOUDS/PRECIP SHOULD HOLD MAXES DOWN. WILL ADD WINDY VERBAGE. CWF: NO REPORTS OF PROBLEMS W/ HIGH TIDE THIS MRNG. TOPS OF TOWERS AROUND SCA CRITERIA ATTM WHILE COASTAL STATIONS WELL BELOW. WINDS WILL PICK UP AS SFC GRAD TIGHTENS. MESO-ETA & 12Z RUC AGREE W/ GOING FCSTS SO NO CHANGES PLANNED. .ILM...SMALL CRAFT ADVY SURF CITY NC TO SOUTH SANTEE RIVER SC. LGE nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE COLUMBIA SC 850 AM EDT TUE APR 4 2000 SATELLITE LOOP SHOWS UPPER CLOUDINESS WILL MOVE EAST OF THE FORECAST AREA EARLY THIS AFTERNOON. DOWNSLOPE WIND SHOULD HELP DIMINISH LOWER CLOUDINESS. THE LATEST RUC SUPPORTS THIS AND SHOWS CLOUDINESS WILL BECOME SCATTERED EARLY THIS AFTERNOON. BELIEVE IT WILL BE ENOUGH SUNSHINE TO PREVENT FALLING TEMPERATURES THIS AFTERNOON. PLAN TO KEEP CHANCE POPS UNTIL AROUND 100 PM. .CAE...WIND ADVISORY FOR AREA LAKES THIS AFTERNOON. RJL sc AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA NATIONAL WEATHER SERVICE ABERDEEN SD 935 AM CDT TUE APR 4 2000 CURRENT FORECAST PACKAGE LOOKS PRETTY MUCH ON TRACK. GOING TEMPS CLOSE TO OR ABOVE FAN GUIDANCE. RUC SOUNDINGS SUGGEST POSSIBILITY OF EVEN WARMER TEMPS WESTERN CWA...BUT WILL LET FORECAST RIDE FOR NOW AND AMEND LATER IF TEMPS LOOK TO BE RISING FASTER THAN EXPECTED. .ABR...NONE LORENS sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 853 PM EDT TUE APR 4 2000 SATELLITE PICTURES UPSTREAM INDICATE MOISTURE (AND CLOUDS) RAPIDLY DECAYING...WITH DEW POINT TEMPERATURES ACROSS MIDDLE TENNESSEE DOWN INTO THE TEENS. SO...IN ACCORDANCE WITH THE LATEST MESO-ETA AND RUC R/H PROGS...WILL ADJUST THE ZONES FOR CLEARING SKIES. ALSO...A SLIGHT REDUCTION TO OVERNIGHT MINS IS IN ORDER (AS SURFACE FLOW WEAKENS)...WITH NEAR RECORD LOWS PROJECTED IN THE SOUTHERN TENNESSEE VALLEY (RECORD LOW OF 28 DEGREES BACK IN 1881 AT CHA). CONSIDERING THE RAPIDLY DRYING ATMOSPHERE...THE FOG THREAT WILL BE REDUCED IN THE SOUTHERN TENNESSEE VALLEY...WITH THE BEST CHANCE OF FOG IN VALLEY LOCATIONS OF THE SOUTHEAST WHERE SURFACE MOISTURE IS TRAPPED. FOR THE SECOND PERIOD...ADJUSTED THE SKY CONDITION TO MOSTLY SUNNY AS THE COMBINATION OF SURFACE HIGH PRESSURE AND DRY AIR WILL PROVIDE FOR AN APPRECIABLE WARMUP. .MRX... NC...NONE. TN...NONE. VA...NONE. DM tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 1006 AM EDT TUE APR 4 2000 COLD FRONT HAS MOVED THROUGH THE AREA AND IS EAST OF THE MOUNTAINS. KMRX/KHTX RADARS SHOWING SHOWERS ALONG UPPER LEVEL TROF. CURRENT VISIBLE SATELLITE SHOWING CLOUDS SLOWLY MOVING EAST LOOKS AS THOUGH PART OF THE CWA COULD BECOME PARTLY CLOUDY. WITH COLD AIR ADVECTION MOVING INTO THE AREA...TEMPERATURES HOLDING STEADY BUT MAY RISE SLIGHTLY THIS AFTERNOON IF SKIES CLEAR. BULK OF HEAVY RAIN OUT OF THE AREA AND LAST SHOWERS MOVING OUT OF THE CWA SLOWLY. WILL ALLOW FLOOD WATCH TO EXPIRE AT NOON EDT. WILL HOLD OFF UPDATE UNTIL NOON. LOOKS AS THOUGH PRECIPITATION WILL EXIT CWA BY NOON AND MAY HAVE TO INCLUDE CHANCE POPS THIS AFTERNOON AS NEXT SHORTWAVE ROTATES AROUND UPPER LEVEL LOW. WILL KEEP AN EYE ON TEMPERATURES. NEW RUC SHOWING THAT MOST OF THE CLOUDS SHOULD REMAIN ACROSS THE CWA. UPDATE OUT AROUND NOON. .MRX... NC...FLOOD WATCH UNTIL NOON EDT TUESDAY FOR ZONES NCZ060>061. TN...FLOOD WATCH UNTIL NOON EDT TUESDAY FOR ZONES TNZ012>014...TNZ035>041...TNZ067>074...TNZ083>087...TNZ099>102. VA...NONE. PDK tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 953 PM EDT TUE APR 4 2000 HAVE SPENT A FAIR AMOUNT OF TIME LOOKING AT HYDRO SITUATION...SO RUNNING A LIL LATE TONIGHT. COORD WITH NERFC....THANX FOR THE CALL. STORM SYS TO BE PULLING OUT ACRS EASTERN QUE INTO WED WITH CYCLONIC SFC FLOW PERSISTING TIL AROUND 18Z WED. UPR L/W TROF TO BE SWEEPING THRU FA AS WELL TONITE. 21Z RUC SHOWS WESTERLY SFC FLOW TO PERSIST OVRNITE (STRONGEST IN THE ST LAW VLY) WITH TEMPS GETTING DOWN INTO THE 30S BY 09Z. PLENTY OF LOW-LVL MOISTURE TO HANG AROUND OVRNITE TONITE AS WELL. PCPN TO START TO CHANGE OVER TO SN AT ELEVATION ON THE NY SIDE BY AROUND 06Z AS INDICATED IN RUC P-TYPE FORECAST. H85 CAA MAXIMIZED ACRS FA TONITE BUT WILL PERSIST INTO WED. LOW-LVL LAPSE RATES AND MOISTURE WILL STILL BE HI INTO WED AS WELL. H85 TEMPS/925 MB WET-BULB TEMPS GRADUALLY GOING NEGATIVE FROM WEST TO EAST ACRS THE FA OVRNITE TONITE AND INTO EARLY WED...ALL SPELLING AN EVENTUAL CHANGEOVER TO SN. ABOVE ALL SPELLS A CONTINUATION OF THE SHOWERY PCPN ACRS THE FA THRU WED. PCPN SHOULD DIMINISH WITH TIME AS WED WEARS ON. PREVIOUS FORECAST HAD GOOD HANDLE ON SITUATION AND WILL ONLY DROP POPS A TAD IN THE VT VLY LOCATIONS TONITE BASED ON CURRENT RADAR TRENDS. MADE A FEW TWEAKS TO OVRNITE WIND FORECAST BASED ON CURRENT OBS TRENDS. ADDED PATCHY FOG TO EASTERN VT ZONES AS WELL. HYDRO-WISE...WILL OPT TO CONTINUE A FEW OF THE WARNINGS THAT ARE OUT ALREADY IN ADDISON...RUTLAND...WINDSOR...AND ORLEANS CTYS BASED ON A FEW REPORTS OF FLOODING THAT WE/VE RECEIVED TONITE AND CURRENT RIVER GAUGE TRENDS. HAVE ALLOWED FFA TO EXPIRE EARLIER THIS EVENING AS ANY FLOODING THAT WILL OCCUR OVRNITE IS ALREADY IN PROGRESS. DON/T EXPECT ANY "NEW" AREAS TO RECEIVE FLOODING OVRNITE. LOOK FOR LATER STATEMENT (FFS) WITH FURTHER DETAILS. WORK ZONES GONE. FINAL ZFP IN A BIT. GOTTA RUN... .BTV...NONE. MURRAY vt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 355 AM CDT WED APR 5 2000 MAIN CONCERNS...PCPN CHCS TDY/TNGT...WINDS LATE THIS AFTN/TNGT... TEMPS TDY. THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE 00Z RUN...WITH THE ETA HANDLING THE LOW THE BEST WITH PLACEMENT AND STRENGTH OVER S ALBERTA AT 06Z. NGM AND AVN WERE TOO DEEP...WITH AVN TOO FAR N. SOME DIFFS EVIDENT IN H85 TEMPS TDY...WITH RUC/AVN ARE THE WARMEST...ETA COOLEST...WITH NGM IN THE MIDDLE. WILL LEAN TWRD ETA FOR DETAILS...BUT WILL BLEND WITH AVN FOR TEMPS TDY. ZONAL FLOW WILL DRAG THE SFC LOW TO NEAR INL BY 00Z WITH COLD FROPA ACRS THE REST OF CWA DURING THE AFTN. H3 JET MAX MOVING ACRS THIS AFTN AS WELL TO AID IN UPR DIVRG. STRONGEST H7 OMEGA CONCENTRATED CLOSER TO THE LOW IN N CWA. BEST MOISTURE REMAINS ACRS N ZONES..SO WILL GO LIKELY POPS THERE...WITH CHANCE POPS ACRS S CWA. TEMPS TRICKY WITH STRONG WAA PATTERN...BUT CLOUDS TO LIMIT FULL SUN. WILL GO ABOVE GUID MOST AREAS TO COVER WARM H85 TEMPS. WINDS THE NEXT PROBLEM. 50 TO 65 KT H85 JET WILL DIVE IN BEHIND THE COLD FRONT LATE THIS AFTERNOON. BEST SHOT AT ADVSY CRITERIA DURING THE AFTN SEEMS TO BE IN MY SW CWA. GOOD CHC OF SUSTAINED 30 MPH/GUSTS TO 45 MPH IN THAT AREA SO WILL ISSUE WIND ADVSY THERE FOR LATE THIS AFTN AND THIS EVENING. REST OF CWA TO SEE NEAR ADVSY WINDS DURING THE EVENING THROUGH 09Z...BUT WILL HOLD OFF ON INCLUDING THEM IN ADVSY FOR NOW TO SEE HOW THE LOW DVLPS AND MOVES. SCATTERED PCPN WILL LINGER OVERNT IN THE N MN ZONES...WITH ANY RAIN CHANGING TO SNOW BY MIDNIGHT. WENT W/ 1000-850 THCKNS FOR TIMING ON CHANGEOVER. A FEW EVENING SPRINKLES AND OVERNIGHT FLURRIES POSSIBLE ACRS THE S AND SE CWA IN THE WRAP AROUND MSTR. COLD AIR DRIVING IN BEHIND THE LOW WILL PUT LOWS CLOSE TO GUID. THURS SHLD BE DRY AS A WEAK SFC RIDGE SLIDES ACROSS THE AREA. COOLER GUID NUMBERS GENERALLY FOLLOWED. SOME CHANGES IN THE EXTENDED... ESPECIALLY ON FRI AS AVN NOW SHOWING THE LOW GOING FARTHER SOUTH. THE MAIN PRECIPITATION BAND IS PROGGED SOUTH OF OUR AREA...SO WILL PULL BACK ON PCPN WORDING FRI. .DLH...WIND ADVISORY FOR LATE THIS AFTERNOON AND THIS EVENING FOR MNZ025-033>036-038-WIZ006. SHIMON mn EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 925 AM EDT WED APR 5 2000 CURRENTLY...GUSTY NORTHWEST TO NORTH FLOW RESULTING IN BRISK CONDITIONS. WIND CHILLS RANGED FROM THE MID 30S TO THE LOWER 40S AROUND SUNRISE. CANAVERAL PROFILER AND AREA WINDS AT 2000 FEET WERE AROUND 25 KNOTS. AS A RESULT OF THIS...WINDS WERE RUNNING ABOVE THOSE IN THE FORECAST. SCATTERED CLOUDS WERE ALONG AND EAST OF THE GULF STREAM AND MOVING DUE SOUTH. TODAY...LATEST RUC FOLLOWS TREND OF THE OTHER SHORT RANGE MODELS IN WEAKENING THE PRESSURE GRADIENT/WINDS THIS AFTERNOON. UNTIL THEN THOUGH...EXPECT IT WILL BE BREEZY SO PLAN TO ADD THIS TO THE FORECAST. A FEW CLOUDS EXPECTED TO PUSH TO SOUTHERN COASTAL SECTIONS AS FLOW VEERS SLIGHTLY TO THE NORTH NORTHEAST...BUT THE EXTREMELY DRY AIR MASS SHOULD EVAPORATE THEM AND KEEP IT A CLOUD FREE DAY OVER LAND AREAS. FIRE WEATHER...RED FLAG CONDITIONS LIKELY TO BE MET BY AFTERNOON ACROSS MOST OF THE AREA DUE TO LOW RH DURATIONS...AND WIND. ONLY EXCEPTION MAY BE ALONG IMMEDIATE COAST AS NNE WIND COMPONENT DEVELOPS AND KEEPS DEWPOINTS SOMEWHAT ELEVATED...BUT WILL KEEP RED FLAG GOING ALL ZONES. ON THU...MODIFICATION OF DRY AIRMASS WILL BE SLOW TO OCCUR...ESPECIALLY OVER NORTHERN AND INTERIOR SECTIONS...IN CLOSER PROXIMITY TO RIDGE AXIS. WILL THEREFORE ISSUE FIRE WEATHER WATCH FOR THU AFTERNOON THOSE AREAS. MARINE...BUOY WAS OVER 20 KNOTS AND SEAS WERE ABOVE ADVISORY THRESHOLD. NORTH TRAJECTORY/COLD ADVECTION SHOULD KEEP SEAS 7 FEET OR ABOVE...EVEN AS GRADIENT SLACKENS DURING THE AFTERNOON. .MLB...SCA FLAGLER BEACH TO JUPITER INLET. RED FLAG WARNING FOR EAST CENTRAL FLORIDA THIS AFTERNOON. FIRE WEATHER WATCH THURSDAY...LAKE...ORANGE...SEMINOLE OSCEOLA...OKEECHOBEE...VOLUSIA AVIATION/FIRE WX...KELLY PUBLIC/MARINE......LASCODY fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1040 AM EDT WED APR 5 2000 GOES-8 WV LOOP SHOWING VIGOROUS UPR LVL SHRTWV TROF MOVG ACROSS NO DAK 11-14Z EVIDENT BY IMPRESSIVE CYCLONIC SWIRL IN IMAGERY. RUC AND OTHER SHRT TERM MODELS PROGGING THIS SHRTWV TO AMPLIFY AS IT DRIVES ESE TWRD THE UPR GRTLKS THIS AFTN/TNGT. STRONG DIFF PVA NOTED AHEAD OF TROF PER H7-H4 AND H5-H3 Q-VECTOR CONVERGENCE PLOTS WITH STRONG DIFF DIVERGENCE ALOFT AIDED BY LOW LVL CONVERGENCE AT NORTHERN TERMINUS OF INTENSIFYING 45-50 KT LOW LVL JET AS IT SHIFTS EAST TWRD WRN UPR MI LATE THIS AFTN. ADDITIONAL ASCENT WILL BE FORCED BY AGEO CIRCULATION ASSCTD WITH RIGHT ENTRANCE REGION OF 80 KT 500 MB JET STREAK PROGD TO RACE INTO CNTRL WIS BY 00Z THIS EVNG. WITH MODERATE LOW LVL WAA AHEAD OF THE UPR LVL TROF AND SLGT COOLING ALOFT... MID LVL LAPSE RATES WILL STEEPEN THIS AFTN ENHANCING MID LVL INSTABILITY. GIVEN SIGNIFICANT INTENSITY OF THE DYNAMICS ASSOCIATED WITH THIS TROF... COMBINED WITH IMPRESSIVE JET ENERGY AND WAA/ISENT LIFT AHEAD OF APRCHNG SFC LOW... AND STEEPENING MID LVL LAPSE RATES... WILL INCLUDE MENTION OF THUNDERSTORMS IN LATE AFTERNOON AND EARLY EVENING PORTION OF THE FCST FOR THE WEST HALF OF UPR MI. PRIMARY LIMITING FACTOR WILL BE MOISTURE AS SFC AND H85 DWPTS REMAIN BONE DRY IN THE 36-40 F RANGE AND ARND 0 C RESPECTIVELY. CURRENT LIGHTING PLOTS AND SFC REPORTS INDICATE THUNDER AHEAD OF THE UPR LVL TROF OVER XTREME SE MANITOBA AND SW ONTARIO 11Z-14Z. AND THE STRONGEST DIFF PVA HAS YET TO AFFECT THIS REGION OF CONVECTION. OTHER MAJOR CONCERN FOR AFTN UPDATE IS PRECIP TYPE. 12Z INL SOUNDING SHOWING ABV FREZ LYR XTNDNG SFC THRU 800 MB... WITH MAX TEMP IN THE WARM LAYER ARND 3 DEG C THROUGH A CONSIDERABLE DEPTH. THIS LAYER VRY DRY HWVR WITH WET BULB BLO FREZ. ANY SIGN PRECIP WOULD EXPERIENCE ENOUGH EVAP COOLING TO CHANGE OVER TO ALL FROZEN PRECIP. HENCE WILL CONTINUE MENTION OF MIXTURE. XPECT MAJORITY OF PRECIP TO BE OF LIGHT ENOUGH INTENSITY HWVR TO REMAIN RAIN. GIVEN LOW FREZ LVL XPECT SLEET WITH MORE INTENSE SHWRS/THUNDER SHWRS. WITH CONTINUED WAA THRU THE AFTN XPECT CHCS FOR FROZEN PRECIP TO GRAD DIMINISH AS WARMER LAYER EXTENDS TO A GREATER DEPTH AND LOW-MID LVLS GRADUALLY MOISTEN. WITH TIGHTENING SFC GRADIENT AHEAD OF 986 SFC LOW XPECT WINDS TO PICK UP FAIRLY RAPIDLY THIS AFTN. WILL CONTINUE CURRENT WIND TRENDS IN ZONES. WITH GOOD MIXING XPECT TEMPS TO JUMP UP WITH INCREASED WAA. EXCEPTION WILL BE SE ZONES ALONG LK MI WHERE CHILLY SE WIND OFF LAKE WILL HOLD TEMPS DOWN. .MQT...GALE WARNING LAKE SUPERIOR. ED F mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 1023 AM CDT WED APR 5 2000 MAIN CONCERN THIS AFTERNOON IS STRONG WINDS AND HIGH TEMPERATURES. 12Z OUN SOUNDING SUPPORTS A HIGH TEMPERATURE OF 91 ASSUMING A MIXED LAYER OF 850 MB WHICH SHOULD BE REACHED BY EARLY TO MID AFTERNOON. 12Z UPPER AIR ANALYSES ALSO SUGGESTS 12 HOUR PROGS FROM LAST NIGHTS' MODELS VERIFIED WELL REGARDING 850-700 MB TEMPERATURES AND WINDS. RECENT RUC GUIDANCE IS ALSO ON TRACK. ONLY MAJOR CONCERN IS VICI PROFILER WHICH SHOWS 45 KNOTS JUST ABOVE THE SURFACE AND IS ABOUT 10 KNOTS STRONGER THAN RECENT MODEL GUIDANCE. STRONGER DOWNSLOPE FLOW ...THUS WARMER TEMPERATURES AND SLIGHTLY STRONGER SURFACE WINDS MAY RESULT. WILL NEED TO MONITOR FOR WIND ADVISORY BUT UNLESS OTHER PROFILERS SHOW STRONGER WINDS WILL LEAN AGAINST IT. FOR NOW WILL ONLY RAISE HIGH TEMPERATURES SLIGHTLY SOME AREAS. EXPECT A COLD FRONT ACROSS THE NORTHERN PLAINS TO CONTINUE SOUTHWARD THIS AFTERNOON REACHING NORTHERN KANSAS BY 00Z. PRE-FRONTAL TROUGH LIKELY TO REMAIN AHEAD OF IT WITH LAST NIGHT'S ETA/RECENT RUC SUGGESTING CONSIDERABLE BAGGINESS OCCURRING IN THE PRESSURE FIELD LATE IN THE DAY ACROSS NORTHWEST OKLAHOMA. WILL MENTION DECREASING WINDS LATE IN THE DAY ACROSS NORTHWEST OKLAHOMA FOR THIS REASON. ...WILL CONTINUE TO MONITOR FOR WIND ADVISORY. .OUN... OK...NONE. TX...NONE. JAMES ok SOUTHWEST IDAHO/SOUTHEAST OREGON AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BOISE IDAHO 300 PM MDT WED APR 05 2000 IN SHORT RANGE LATEST RUC ALIGNS WELL WITH SHORT WAVE AND CLDS OVER NW WITH AC/CI THRU BKE CO AND ENTERING W-CENTRAL MTNS...NRN HARNEY AND MALHEUR COUNTIES FOR THIS EVENING. MESOETA AND AVN PREFERRED IN SHORT RANGE IN TAKING A SOMEWHAT MOIST /CHC POPS N AND SLIGHT CHC S/ BUT LOW AMPLITUDE SYSTEM THROUGH REGION. NGM TOO DRY AND TOO COOL ESPECIALLY TOO COOL FRIDAY WITH FULL SPRING SUNSHINE. THICKNESS COOLING CONCENTRATED N AND CD FROPA MAINLY TIGHTENS GRADIENT OVER BOISE CWFA. BREEZY LOOKS GOOD ONTARIO-MOUNTAIN HOME AT LEAST FOR THURSDAY AFTERNOON BECAUSE WITH TREASURE VALLEY ORIENTED NW-SE...NW JET ALIGNMENT WITH STRONGER WINDS ALOFT TO MIX DOWN FOR BREEZY CONDITIONS. SLIGHT CHC POPS FOR THURSDAY NIGHT SE ZONES THEN RIDGE COMES IN WITH WARMING THICKNESSES AND WARMING LOW ALT TEMPS ESPECIALLY SW PART OF CWA...FOR FRIDAY. SIMILAR TEMPS THU/FRI FOR TWF CO. PREFER UKMET OVERALL WHICH MEANS A CHANGE TO INCREASING CLOUDS SE OREGON SATURDAY AND MUCH OF SW IDAHO FOR SATURDAY. AND GIVES A CHANCE OF SHOWERS OR RW/TRW SRN IDAHO MTNS EACH SUNDAY AND MONDAY. PREFER FARTHER S TRACK OF ECMWF AND NOGAPS OVER MRF...AND PREFER LOWER AMPLITUDE/FASTER EC OVER NOGAPS BECAUSE UPPER LOW IS EJECTING INTO LONGWAVE U.S./CANADIAN W COAST RIDGE. FMR MIGHT BE TOO WARM ON MAXES SUN/MON BUT THEY DO HAVE CHC POPS COVERED. .BOI...NONE. id AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 525 PM EDT WED APR 5 2000 FCST CONCERNS DEAL WITH EFFECTS OF SHIFTING LOW PRESSURE IN REGARD TO HIGH WIND POSSIBILITIES AND -SHRA/-SHSN TONIGHT. 20Z SFC ANALYSIS SHOWS LOW PRESSURE OVR NWRN MN BEGINNING TO MOVE SOUTHEAST ATTM. AHEAD OF LOW IN AREA OF STRONG ISENTROPIC ASCENT AT 290K...AREA OF WIDESPREAD LGT RA AND LGT SN EXISTS OVER NRN MN INTO SRN ONTARIO AND MANITOBA. BIGGEST STORY THIS AFTN ARE WINDS OVR NRN PLAINS AS WINDS HAVE GUSTED AS HIGH AS 55 KTS OVR PARTS OF THE DAKOTAS. TONIGHT...AS LOW DIVES SOUTHEAST ARRIVING OVR ERN UPR MI BY 12Z PER 18Z ETA...LGT RAIN WL OVR SPREAD AREA. 88D RETURNS STRETCHING INTO WRN UPR MI ALTHOUGH SFC OBS POINT TO PRECIP ONLY BEGINNING TO REACH GROUND IN IWD WITH 7SM VSBY. AS UPR MI STAYS IN WAD THRU EVENING HRS PRECIP TYPE WL STAY LIQUID. FCST SOUNDING ALSO SHOW ABOVE FREEZING LAYER STAYING ABOVE H8 THROUGH 06Z. ONLY EXCEPTION IS IN ERN UPR MI WHERE COLD AIR AT H8 HAS HUNG ON THROUGHOUT DAY AS LATEST RUC SHOWS H8 TEMPS AOB ZERO OVER EXTREME ERN UPR MI THRU 03Z. RESULT IS PRECIP AS A RA/SN MIX THROUGHOUT NIGHTTIME HRS. IN WRN UPR MI...18Z ETA PROGS H8 TEMPS TO DROP BELOW ZERO C BY 09Z OVR KEWEENAW...AND BY 12Z OVR CENTRAL UPR MI. IN THOSE AREAS WENT WITH RAIN...POSSIBLY MIXING WITH SN OVR HIGHER TERRAIN LATE. AS FOR THE WINDS...HAVE BACKED DOWN FM YESTERDAYS FCST MAINLY DUE TO LOW PASSING ALMOST DIRECTLY OVER THE FA. AS OF NOW IT APPEARS THE BEST WIND WL REMAIN TO THE SOUTH OF THE FA AS THAT IS WHERE THE BEST DECENT BEHIND SHRTWV WL REMAIN. ONLY COUNTY WITH CHANCE OF SEEING VRY STRONG WINDS WL BE GOGEBIC COUNTY AS THEY WL BE RIGHT ON FRINGE OF THE STRONG WIND CORE AT H9 AROUND 40KT...WORKING AGAINST FCST GUSTS TO 45 KT WL OF COURSE BE TIME OF DAY. THURSDAY...AS LOW RAPIDLY PULLS EAST...NEAR GEORGIAN BAY BY 18Z PER 18Z ETA. PRECIP WL QUICKLY TAPER OFF AS BEST FORCING EVADES THE FA. WINDS SHOULD ALSO DIE DOWN...ESPECIALLY WEST AS SFC RIDGE BEGINS TO BUILD IN FM WEST. IN ERN UPR MI CAA COMBINED WITH CLOSE PROXIMITY TO VORT DECENT AREA SHOULD CONTINUE GUSTY WINDS UNTIL AFTERNOON. NEXT STORM OF MENTION HAS ALSO TRENDED AWAY FM A MAJOR WX PRODUCER WITH LATEST MRF...AVN...AND UKMET RUNS (EUROPEAN UNAVAILABLE). ALL MODELS DIG VORT MAX MORE AND ONLY SKIRT ERN UPR MI WITH H8-H5 QVECTOR CONVERGENCE AND H7 OMEGA BY 18Z FRI PER AVN. RESULT IS PULLING BACK ON CATEGORICAL WORDING TO CHANCE...BEST OVR ERN UPR MI. .MQT...NONE. JLA mi