AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 430 AM MDT MON APR 16 2007 .SHORT TERM...BIGGEST CHALLENGE TODAY: TIMING AND COVERAGE OF PRECIP...SNOW LEVEL...AND T-STORM CHANCES. TIGHTLY WOUND UPR LOW VORTEX EVIDENT ON SATELLITE IMAGES AND LATEST RUC HEIGHT AND WIND FIELDS CONTINUING TO TREK SEWRD FM ITS CURRENT LOCATION OVER EXTREME SWRN ARIZONA. QG OMEGA AND HT CHANGE FIELDS SUPPORT THIS SELY PATH ACROSS SERN ARIZONA AND SRN NEW MEXICO NEXT 24-36 HRS...PRETTY MUCH TOO FAR SOUTH TO HAVE MUCH IMPACT ON WEATHER UP HERE. HOWEVER...NOT OUT OF THE WOODS AS A STRONG COLD FRONT CURRENTLY DROPPING SWRD THRU NRN PORTIONS OF THE CWFA MAY PROVIDE A FOCUS FOR SHOWERS AND EVEN T-STORMS OVER THE PALMER DIVIDE AND ALONG EAST SLOPE OF THE FRONT RANGE THIS AFTERNOON AND OVERNIGHT. LATEST NAM AND MM5 SHOW THE FRONT THROUGH THE I-25 URBAN CORRIDOR BY 15Z THIS MORNING...WITH BRISK NELY FLOW IN ITS WAKE. LOW LEVEL QG OMEGA FIELDS SHOW INCREASING ASCENT WITH RELATIVELY MOIST UPSLOPE FLOW DEEPENING DURING THE AFTERNOON. PRECIPITABLE WATER VALUES UP ALONG THE FRONT RANGE INCREASE TO AROUND 0.40-0.45 INCH BY 21Z...AND WITH DIVERGENCE INCREASING ALOFT AS THE UPR LOW PASSES TO OUR SOUTH...SHOW SEE A SHOWER DEVELOP IN THE FOOTHILLS AND OVER THE MTNS BY 18Z TODAY. HOWEVER...NOT UNTIL AFTER 21Z OR AS LATE AS 00Z/TUE DO I EXPECT TO SEE THE HEAVIEST PRECIPITATION. AT THIS TIME APPEARS GREATEST PRECIP AMOUNTS WILL BE OBSERVED IN THE SRN FRONT RANGE FOOTHILLS...HIER TERRAIN OF EASTERN PARK COUNTY...AND UP AGAINST THE FOOTHILLS IN JEFFERSON AND DOUGLAS COUNTIES. AS FOR SNOW LEVELS...SEE THEM STARTING OUT HIGH TODAY AROUND 9000-9500 FEET...BUT BY 00Z/TUE...LEVELS FALL TO AROUND 8000 FEET OR SO BASED ON WETBULB ZERO FCST. ITS OVERNIGHT WITH SNOW LEVELS LOWERING TO NEAR 6500 FEET BY MIDNIGHT WHEN BEST SNOW ACCUMS LIKELY TO OCCUR. HOW MUCH...STILL TOUGH TO SAY EVEN NOW. MODEL SNOW AMOUNTS LOOK WAY OVER DOWN. EVEN CUTTING THEM IN HALF WOULD GIVE US UPWARDS OF A FOOT OR MORE IN THE HIGHER SRN FOOTHILLS. FOR NOW WILL KEEP AMOUNTS BELOW ADVISORY CRITERIA AND LEAVE IT TO THE DAY SHIFT TO GET A BETTER HANDLE ON ALL THIS. AS FOR T-STORMS...HAVE BACKED OFF OF T-STORM CHANCES FARTHER OUT ON THE PLAINS WHERE AIRMASS LIKELY TO BE TOO STABLE AND LACKING LOW LEVEL MOISTURE. CLOSER TO THE HIR TERRAIN INCLUDING THE PALMER DIVIDE...WILL STICK WITH ISOLATED T-STORM COVERAGE THIS AFTERNOON THROUGH THIS EVENING. .LONG TERM...WEATHER SHOULD BE WINDING DOWN EARLY TUESDAY MORNING AS DOWNWARD Q-G VERTICAL MOTION SPREAD ACROSS THE FORECAST AREA. CLOUDS SHOULD ALSO BEGIN TO BREAK UP BY AFTERNOON AS SUBSIDENCE AND DRYING TAKE HOLD. NEXT SYSTEM WILL BEGIN TO AFFECT THE AREA WEDNESDAY WITH INCREASING SOUTHWEST FLOW ALOFT AND BREEZY CONDITIONS DEVELOPING. THE LATEST NAM AND GFS RUNS ARE STRONGER AND DEEPER WITH THE SHORT WAVE. THIS WOULD BRING A BETTER CHANCE OF SNOW TO THE MOUNTAINS WEDNESDAY NIGHT INTO THURSDAY WITH STRONGER COLD ADVECTION AND OROGRAPHICS. IN ADDITION...THE LATEST RUNS ALSO SHOW A RIBBON OF HIGHER THETA-E ADVECTING NORTHWARD ACROSS THE HIGH PLAINS. IF UPPER TROUGH IS DEEP AND COLD ENOUGH ALOFT...AND FAST ENOUGH...THEN THERE WOULD BE POTENTIAL FOR SOME THUNDERSTORMS AND EVEN POSSIBILITY OF SEVERE WEATHER ACROSS THE NORTHEAST PLAINS LATE WEDNESDAY. A LOT OF UNCERTAINTIES REGARDING THIS...BUT STILL SOMETHING TO KEEP AN EYE ON. NO SIGNIFICANT CHANGES PAST THURSDAY. WARMER AND DRY WEATHER ON TRACK FOR FRIDAY...AND THEN POTENTIAL FOR ANOTHER STORM SYSTEM NEXT WEEKEND. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. $$ BAKER/BARJENBRUCH co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 347 AM MDT SUN APR 15 2007 .SHORT TERM... (TODAY AND TONIGHT) ...SIGNIFICANT TEMPERATURE REBOUND IN MOST LOCATIONS TODAY... CURRENTLY...VERY IMPRESSIVE SNOW MELTING OCCURRED YESTERDAY. APPROXIMATELY...A 70 MILE WIDE SNOW FIELD REMAINED FROM TRINIDAD TO LAMAR SHORTLY BEFORE SUNSET YESTERDAY PER VISIBLE SATELLITE IMAGERY. ALSO...PATCHES OF SNOW REMAINED IN THE SOUTHWEST CORNER OF THE SAN LUIS VALLEY AND WET MOUNTAIN VALLEY. TEMPERATURES ALREADY WARMING ALOFT PER HIGH TERRAIN AWOS SENSORS AROUND 10K-11K FT MSL...AND APPROACHING 30F WHICH IS 10-25 DEGREES WARMER THAN YESTERDAY AT THIS TIME. THEREFORE...THE WARM AIR IS BUILDING ALOFT. THIS WAS IN RESPONSE TO A LARGE UPPER LEVEL RIDGE OVER THE ROCKIES AND SLOWLY MOVING EASTWARD. NEXT CLOSED LOW PRESSURE SYSTEM WAS SPINNING INTO SOUTHERN CA PER WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES ANIMATION. NICE BAROCLINIC LEAF...MAINLY MIDDLE AND HIGH LEVEL CLOUDS...JUST AHEAD OF THIS SYSTEM OVER THE GREAT BASIN PER IR SATELLITE IMAGERY. NOT MUCH IN THE WAY OF PRECIPITATION FALLING OUT OF THESE CLOUDS RIGHT NOW. JUST A FEW THINNING PATCHES OF CI/CS MIGRATING IN FROM THE WEST OVER THE CENTRAL ROCKIES...BUT DISSIPATE AS THEY HIT THE RIDGE AND SUBSIDENT FLOW. TODAY...UPPER LEVEL RIDGE IS FORECAST TO SLOW MOVE EASTWARD AND FLATTEN OUT. THE SYSTEM OUT WEST SLOWLY MOVES EASTWARD...TOO. RELATIVELY DEEP SOUTHERLY FLOW DEVELOPS OVER THE CENTRAL ROCKIES. WITH JUST SOME CI/CS CLOUDS AND 700MB TEMPERATURES WARMING TO +4C TO +6C OVERHEAD...MAXIMUM TEMPERATURES WILL PROBABLY BE 5 TO 15 DEGREES WARMER THAN YESTERDAY. THE BIGGEST WARMING SHOULD BE OVER THE FAR SOUTHEASTERN CO PLAINS. SHOULD SEE SOME FIERCE SNOW MELT TODAY GIVEN THE WARMER TEMPERATURES...SUNSHINE...AND WIND PICKING UP. THIS MAKES FOR VERY CHALLENGING MAXIMUM TEMPERATURE FORECASTS IN THE FAR SOUTHEAST CORNER AROUND LAMAR. IF THE REMAINDER OF THE SNOW CAN MELT THIS MORNING AND THE WIND PICKS UP THIS AFTERNOON...THEN LAMAR COULD VERY WELL HIT 70F THANKS TO MIXING...OR THE SNOW MELTS SLOWLY AND THE WIND DOES NOT PICK UP RESULTING IN A HIGH OF 50F. TOUGH CALL AND WILL SPLIT THE DIFFERENCE. TONIGHT...SLOW MOVING CLOSED LOW HEADS INTO AZ. SOUTHERLY FLOW INCREASES TONIGHT...SO HIGH TERRAIN FREE-AIR TEMPERATURES COULD BE STEADY MUCH OF THE NIGHT ALONG WITH BREEZY CONDITIONS. SHALLOW COLD FRONT TAKES AIM ON NORTHERN CO IN RESPONSE TO A NORTHERN JET STREAM SYSTEM MIGRATING ACROSS THE NORTH CENTRAL UNITED STATES. FOR CONTINUITY WITH SURROUNDING OFFICES NEAR THE CONTINENTAL DIVIDE... WILL ADD SOME VERY LOW POPS/WX. METZE .LONG TERM... (MONDAY THROUGH NEXT SATURDAY) PRIMARY METEOROLOGICAL ISSUE FOR THE LONGER TERM CONTINUES TO BE IMPACT THAT CLOSED UPPER LOW WILL HAVE ON REGION MONDAY INTO TUESDAY. LATEST LONGER TERM COMPUTER MODELS SUGGEST THAT CLOSED UPPER LOW WILL BE CENTERED OVER NORTHWEST ARIZONA AT 12Z MONDAY AND THEN MOVE INTO SOUTH-CENTRAL NEW MEXICO BY 12Z TUESDAY BEFORE PUSHING INTO FAR SOUTH-CENTRAL OKLAHOMA BY 00Z WEDNESDAY. WILL CONTINUE TO PAINT HIGHEST PRECIPITATION POTENTIAL OVER THE CWFA FROM MONDAY AFTERNOON INTO TUESDAY WITH POTENTIALLY HEAVY HIGHER ELEVATION SNOWS EMBEDDED WITH THIS SYSTEM. A RETURN TO WARMER AND RELATIVELY DRIER CONDITIONS ARE THEN EXPECTED FROM TUESDAY NIGHT INTO NEXT FRIDAY AS A GENERALLY ZONAL TO SOUTHWEST UPPER FLOW ALOFT PATTERN EXPECTED. ANOTHER UPPER DISTURBANCE IS EXPECTED TO BRING UNSETTLED CONDITIONS TO THE CWFA BY NEXT SATURDAY. WARMEST TEMPERATURES FOR THE LONG TERM SHOULD BE NOTED FROM WEDNESDAY INTO NEXT FRIDAY. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 243 AM EDT SUN APR 15 2007 .SYNOPSIS... STRONG LOW PRESSURE IN THE FORECAST AREA EARLY TODAY WILL BE NEAR THE MIDDLE ATLANTIC COAST MONDAY AND THE NEW ENGLAND COAST TUESDAY. THE COLD FRONT ASSOCIATED WITH THE LOW WILL MOVE THROUGH THE FORECAST AREA EARLY TODAY. IT WILL BE WINDY BEHIND THE FRONT. && .NEAR TERM /UNTIL NOON TODAY/... THE MAIN FORECAST PROBLEM IS THE SEVERE WEATHER THREAT EARLY THIS MORNING. THE LATEST ANALYSIS SHOWED THE COLD FRONT EXTENDING THROUGH GEORGIA. MSAS INDICATED LI/S NEAR -1 AHEAD OF THE FRONT. SHEAR WAS VERY STRONG. NEXRAD INDICATED H85 WIND NEAR 45 KNOTS. THE JET WAS NEAR 55 KNOTS OVER GEORGIA. THE LATEST RUC FORECASTED H85 WIND TO INCREASE TO NEAR 60 KNOTS OVER THE FORECAST AREA BY 12Z. THE KCAE VAD INDICATED MAINLY UNI-DIRECTIONAL SHEAR EARLY THIS MORNING. THE WARM FRONT AND ITS ASSOCIATED SHEAR HAD LIFTED JUST NORTH OF THE FORECAST AREA. THEREFORE...THE MAIN THREAT APPEARS TO BE STRAIGHT-LINE WIND...BUT SURFACE TO 1 KM HELICITY INDICATED A TORNADO THREAT AS WELL. THE LATEST SPC ANALYSIS SHOWED SR HELICITY 400 TO 500 M**2/S**2. STRONG INSTABILITY ALOFT WITH CROSS TOTALS NEAR 25 AND FAVORABLE WET-BULB ZERO HEIGHTS ALSO SUPPORT A POSSIBILITY OF DAMAGING HAIL. && .SHORT TERM /NOON TODAY THROUGH 6 AM MONDAY/... EXPECT THE COLD FRONT WILL HAVE MOVED THROUGH THE FORECAST AREA BY AFTERNOON WITH H85 COLD ADVECTION DOMINATING. COLD AIR ALOFT ASSOCIATED WITH THE STRONG TROUGH SUPPORTS KEEPING A SMALL POP THIS AFTERNOON. THE MAIN PROBLEM THIS AFTERNOON SHOULD BE WIND. THE MAV MOS SUPPORTS UPGRADING THE LAKE WIND ADVISORY TO A GENERAL WIND ADVISORY. THE PRESSURE GRADIENT SHOULD REMAIN TIGHT TONIGHT BUT WITH DIMINISHED MIXING BELIEVE WIND SHOULD BE LESS. THE MAV MOS SUPPORTS A LAKE WIND ADVISORY TONIGHT. && .LONG TERM /MONDAY THROUGH SATURDAY/... STRONG LOW PRESSURE WELL NORTHEAST OF THE REGION WITH HIGH PRESSURE IN THE MISSISSIPPI RIVER VALLEY WILL CONTINUE TO DOMINATE MONDAY. THE MOS INDICATED A LAKE WIND ADVISORY WILL LIKELY BE NEEDED AGAIN MONDAY. WIND SHOULD BE LESS MONDAY NIGHT AND TUESDAY WITH THE RIDGE CLOSE TO THE AREA. NO CHANGES PLANNED FOR THE PERIOD WEDNESDAY THROUGH SATURDAY. WEAK LOW PRESSURE SUPPORTS A SMALL POP WEDNESDAY AND THURSDAY. OTHERWISE...DRY RIDGING SHOULD DOMINATE. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... 06Z-10Z...COLD FRONT WEST OF THE REGION WITH STRONG ENVIRONMENTAL WINDS 60-65 KT AT 5 THOUSAND FEET PRODUCING STRONG WIND SHEAR. CONDITIONS BECOMING MARGINAL IFR FOR CIGS NEAR 2KFT AND VSBYS 3-4 MILES IN SHOWERS AND THUNDERSTORMS. HEAVY RAIN MAY LOWER VISIBILITIES BELOW 1 MILE TEMPORARILY. 10Z-14Z...COLD FRONT MOVES THROUGH AND TAKES THREAT OF SEVERE STORMS AWAY. MVFR CONDITIONS REMAIN FOR CIGS NEAR 3KFT. VISIBILITIES GENERALLY 7 MILES BUT A FEW SHOWERS ARE POSSIBLE THAT MAY REDUCE VSBYS TO 5-6 MILES. 14Z-18Z UPPER END MVFR CEILINGS AT 3KFT. SURFACE WINDS WILL BE STRONG...WITH SUSTAINED 20 KNOTS...AND GUSTS TO 30 KNOTS. 18Z-06Z...SKIES CLEARING OUT. WINDS WILL REMAIN STRONG THROUGH THE REMAINDER OF THE TAF PERIOD. THROUGH THE EXTENDED PERIOD...SKIES EXPECTED TO REMAIN VFR. WINDS WILL REMAIN STRONG INTO MONDAY...THEN DECREASE TUESDAY. && .FIRE WEATHER... DESPITE THE EXPECTED WIND TODAY DO NOT BELIEVE RED FLAG CONDITIONS WILL BE REACHED BECAUSE OF HIGH FUEL MOISTURE AND RELATIVE HUMIDITY ABOVE THE CRITERIA. && .HYDROLOGY... THE GFS...NAM...AND SREF DATA INDICATE TOTAL RAINFALL NEAR 1 INCH. THREE-HOUR FLASH FLOOD GUIDANCE IS ABOVE 3 INCHES. DO NOT PLAN TO ISSUE A FLOOD WATCH AT THIS TIME...BUT POSSIBLE TRAINING WITH PRECIPITABLE WATER NEAR 2 INCHES COULD SUPPORT ISOLATED FLOODING PROBLEMS IN POOR-DRAINAGE AREAS EARLY THIS MORNING. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...LAKE WIND ADVISORY UNTIL NOON EDT TODAY FOR SCZ015-016-018- 020>022-025>031-035>038-041. LAKE WIND ADVISORY FROM 8 PM TO 10 PM EDT THIS EVENING FOR SCZ015-016-018-020>022-025>031-035>038-041. WIND ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR SCZ015-016-018-020>022-025>031-035>038-041. GA...LAKE WIND ADVISORY UNTIL NOON EDT TODAY FOR GAZ040-063>065-077. LAKE WIND ADVISORY FROM 8 PM TO 10 PM EDT THIS EVENING FOR GAZ040-063>065-077. WIND ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR GAZ040-063>065-077. && $$ SYNOPSIS...05 NEAR TERM...05 SHORT TERM...01 LONG TERM...05 AVIATION...01 FIRE WEATHER...05 HYDROLOGY...05 ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1045 AM CDT MON APR 16 2007 .DISCUSSION... FORECAST PRETTY MUCH LOOKS ON TRACK AND ONLY MADE MINOR ADJUSTMENTS TO THE HOURLY GRIDS TODAY. AMPLE SUNSHINE TODAY WITH JUST A FEW CUMULUS CLOUDS OVER EASTERN ILLINOIS WHERE NORTH WINDS A BIT STRONGER. HIGHS GETTING BACK TO NORMAL IN THE 60S WITH COOLEST READINGS NEAR THE INDIANA BORDER. 15Z/10 AM SURFACE MAP SHOWS MONSTER STORM OVER LONG ISLAND NY WITH 973 MB LOW PRESSURE WITH ITS NORTHERLY WINDS AROUND 10 MPH STILL AFFECTING EASTERN IL. THIS VERY INTENSE LOW WAS AS DEEP AT 968 MB AROUND DAWN JUST SOUTH OF NYC. 1025 MB HIGH PRESSURE OVER THE LOWER MS AND RIDGING NORTHWARD ACROSS THE MS VALLEY INTO WI. THIS HIGH PRESSURE WAS PROVIDING SUNNY SKIES TO IL THIS MORNING WITH LIGHT TO CALM WINDS OVER WESTERN IL. AFTER ANOTHER FROSTY EARLY MORNING WITH LOWS IN THE LOW TO MID 30S...TEMP HAVE REBOUNDED INTO THE UPPER 40S AND LOWER 50S. AIR MASS REMAINS VERY DRY UNDER HIGH PRESSURE RIDGE WITH DEWPOINTS IN THE MID TO UPPER 20S OVER CENTRAL/SE IL WHILE 30S OVER WESTCENTRAL AND SW IL. RUC AND WRF SHOW SURFACE HIGH PRESSURE RIDGE TO SLOWLY MOVE EAST ACROSS IL TODAY AND SLIP EAST INTO INDIANA TONIGHT. THIS HIGH PRESSURE COMBINED WITH UPPER LEVEL HIGH PRESSURE OVER THE EASTERN PLAINS WILL CONTINUE AMPLE SUNSHINE THIS AFTERNOON. FEW TO SCATTERED CUMULUS CLOUDS COULD DEVELOP THIS AFTERNOON EAST OF I-57 ESPECIALLY NEAR THE INDIANA BORDER. 850 MB TEMPS ARE 6 TO 8C THIS AFTERNOON OR ABOUT 5C WARMER THAN YESTERDAY. THIS SUPPORTS WARMER HIGHS IN THE MID TO UPPER 60S WITH WARMEST READINGS WEST. THIS IS ACTUALLY CLOSE TO NORMAL HIGHS FOR MID APR. && .PREV DISCUSSION... BLOCKING PATTERN ACROSS CONUS AND NORTH ATLANTIC WILL KEEP THE MIDWEST UNDER MID-LEVEL RIDGING THROUGH MUCH OF THE PERIOD... WITH SOME SCATTERED SHOWERS POSSIBLE TUESDAY NIGHT/WED AHEAD OF A CLIPPER SYSTEM RIDING DOWN THE CREST OF THE RIDGE. SHORT TERM...TODAY THROUGH WEDNESDAY... WEATHER ACROSS THE NATION IS DOMINATED BY STRONG NOREASTER OFF SANDY HOOK NJ... WHICH CONTINUES TO DEEPEN RAPIDLY THIS MORNING. MEANWHILE... A CUTOFF UPPER LOW IS SLOWLY MOVING INTO SOUTHWESTERN ARIZONA... WHILE A STRONG SYSTEM LOOMS OVER THE PACIFIC. BETWEEN THE SOUTHWESTERN CUTOFF AND THE STRONG EAST COAST STORM... SHARP MID-LEVEL RIDGING CONTINUES TO BUILD IN ACROSS THE MIDWEST... PROMISING FAIR WEATHER AND NEAR NORMAL TEMPERATURES FOR THE REGION OVER THE NEXT COUPLE OF DAYS. THE ONLY FLY IN THE OINTMENT CONTINUES TO BE WITH A SHORTWAVE CURRENTLY MOVING ACROSS THE CANADIAN PRAIRIES. AS EXPECTED IN A COMPLICATED BLOCKING PATTERN... MODEL SOLUTIONS HAVE BEEN QUITE DIVERGENT IN THEIR HANDLING OF THIS SYSTEM AS IT DROPS DOWN THE CREST OF THE RIDGE... AND ITS SUBSEQUENT INTERACTION WITH THE CUTOFF LOW MOVING ACROSS THE DESERT SOUTHWEST. BY ITSELF... THIS NORTHERN STREAM DISTURBANCE AND ATTENDANT COLD FRONT WOULD BE MOVING INTO A RATHER DRY ENVIRONMENT... WITH STRONG MID LEVEL CAPPING IN PLACE INHIBITING CONVECTION IN THE ABSENCE OF ANY STRONG FORCING. HOWEVER... SOME ADDITIONAL MID/UPPER LEVEL MOISTURE WILL BE BROUGHT NORTHWARD AHEAD OF THE SLOW-MOVING SOUTHWESTERN CUTOFF... INTO THE LOWER MISSISSIPPI VALLEY TUE/WED. STILL BELIEVE THE GFS IS MOVING THE CUTOFF AND ITS ATTENDANT MOISTURE TO THE EAST AND NORTH FAR TOO QUICKLY CONSIDERING THE BLOCKING PATTERN UPSTREAM... AND THE STRENGTH/AMPLITUDE OF THE RIDGING ACROSS THE CENTRAL US. ECMWF REMAINS SLOWER THAN THE GFS... AND EVEN IT MAY BE A LITTLE FAST. THE THINKING HERE IS THAT THE BULK OF THE MOISTURE ASSOCIATED WITH THE CUTOFF WILL REMAIN SOUTH OF THE OHIO VALLEY AND LARGELY WEST OF THE MISSISSIPPI... RESULTING IN RELATIVELY LOW CHANCES FOR PRECIP AHEAD OF THE CLIPPER TUESDAY AFTERNOON AND EVENING. THE NAM SUPPORTS A HIGHLY AMPLIFIED NORTHERN STREAM SYSTEM MOVING INTO THE AREA WEDNESDAY... BUT IT MAY OVER DEVELOPING THIS SYSTEM DUE TO STRONG DIFFLUENCE ALOFT AHEAD OF THE CUTOFF LOW... WHICH IS PROBABLY TOO FAR EAST IN THE NAM DEPICTION. WILL STILL NEED TO MONITOR THIS TREND... AS NAM SOLUTION WOULD PROMOTE INCREASED CLOUDS AND SHOWER CHANCES ON WEDNESDAY DUE TO COLD POOL ALOFT... AND A SLIGHTLY PROLONGED PERIOD OF COOLER AIR MID-WEEK. LONG TERM...THURSDAY THROUGH SUNDAY... THE STRONG PACIFIC SYSTEM... CURRENTLY WELL OFF THE WEST COAST... PROMISES A FAIRLY QUICK BREAK DOWN OF THE BLOCKING PATTERN ACROSS THE CONUS... AND A SHIFT TO A MORE SPRING-LIKE PATTERN... WITH PERSISTENT TROUGHING IN THE WEST BRINGING SOUTHWEST FLOW TO THE CENTRAL US. TIMING OF ANY INDIVIDUAL SHORTWAVE DISTURBANCES EJECTING FROM THE MEAN WESTERN TROUGH STILL DIFFICULT TO PIN DOWN... BUT APPEARS MOST LIKELY THE FIRST DISTURBANCE WILL AFFECT THE AREA IN THE SUNDAY-MONDAY TIME FRAME... BRINGING THE POSSIBILITY OF THUNDERSTORMS ALONG WITH IT. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ HUETTL/HARDIMAN il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 243 PM CDT MON APR 16 2007 .DISCUSSION... DAYS 1-2... MAIN FORECAST CONCERN IS THE TIMING AND AMOUNT OF PRECIP TOMORROW, ALONG WITH TEMPERATURES. WATER VAPOR LOOP AND 12Z MAPS HAVE A CUTOFF LOW ROTATING OUT OVER THE DESERT SOUTHWEST, WITH A NORTHERN BRANCH SHORTWAVE MOVING THROUGH SOUTH CENTRAL CANADA. BOTH THE 700 AND 850MB LEVELS HAD FAIRLY WARM TEMPS EXTENDING INTO THE ROCKIES AND PLAINS, WITH TEMPS IN THE TEENS C AT 850MB. HOWEVER, A COLD FRONT WAS BRINGING SOME COOLER 850MB TEMPS IN THE SINGLE DIGITS ACROSS MT AND THE WESTERN DAKOTAS. TONIGHT, THE NORTHERN BRANCH SHORTWAVE TROUGH WILL MOVE EASTWARD AND HELP BRING THE COLD FRONT FURTHER SOUTH INTO NORTHERN KS. WE SHOULD STILL SEE SOME DECENT SOUTHERLY WINDS AHEAD OF THE FRONT TONIGHT, WHICH SHOULD HELP KEEP TEMPS IN THE LOW TO MID 40S. THE SOUTHERN CUTOFF LOW WILL BEGIN TO MOVE OUT INTO THE PLAINS THROUGH TX AND OK TOMORROW. ISENTROPIC LIFT AHEAD OF THE SYSTEM IS FAIRLY WEAK OVER US, WITH BETTER UPGLIDE TO OUR SOUTH AND EAST. HOWEVER, BOTH THE GFS AND NAM HAVE GOOD 700MB OMEGA AS THE MAIN LOW COMES OUT, MAINLY OVER OUR SOUTHEAST. THUS, BUMPED UP POPS OVER THAT AREA FOR TOMORROW AFTERNOON. CAPE VALUES ARE FAIRLY WEAK, AROUND 300 J/KG, SO KEPT THE MENTION AS SHOWERS AND ISOLATED THUNDERSTORMS. THE COLD FRONT WILL ALSO HAVE COME THROUGH BY TUESDAY AFTERNOON. THE AIR WILL BE MORE PACIFIC IN NATURE THAN BITTERLY COLD, BUT WITH 850MB TEMPS IN THE SINGLE DIGITS ALONG WITH CLOUDS AND PRECIP, WE SHOULD BE SIGNIFICANTLY COOLER THAN MONDAY. LOWERED HIGHS ANOTHER FEW DEGREES INTO THE UPPER 50S TO NEAR 60. PRECIP MAY STILL BE WRAPPING AROUND THE UPPER LOW TUESDAY EVENING, BUT SHOULD TAPER OFF AFTER MIDNIGHT AS THE SYSTEM MOVES OFF TO THE EAST. CLOUDS SHOULD LINGER, AND THERE MAY EVEN BE A BIT OF STRATUS BY WEDNESDAY MORNING, ALTHOUGH THINK THAT THE GFS IS OVERDONE IN MOISTURE AND FAVOR THE MORE PATCHY NAM AND RUC. KEPT LOWS IN THE 40S. SHORTWAVE RIDGING TAKES OVER BY WEDNESDAY BETWEEN SYSTEMS, WITH THE SFC HIGH OVER THE PLAINS MOVING EAST AND LEE TROUGHING RE-DEVELOPING OVER THE ROCKIES. WITH CLEARING SKIES, SOUTHERLY WINDS, AND 850MB TEMPS RETURNING TO THE TEENS, HIGHS IN THE UPPER 60S TO MID 70S CONTINUE TO LOOK GOOD. DAYS 3-7... MAIN FORECAST CHALLENGES FOR THIS EXTENDED PERIOD ARE CHANCES OF THUNDERSTORMS, SOME POSSIBLY SEVERE, ON THURSDAY AND AGAIN ON SATURDAY AFTERNOON AND EVENINGS. A STRONG SHORTWAVE TROUGH WILL EJECT INTO THE NORTHERN AND CENTRAL HIGH PLAINS ON THURSDAY FORCING A DRYLINE TO FORM OVER WESTERN KANSAS. GOOD LOW LEVEL MOISTURE RETURN IS INDICATED BY THE MODELS AHEAD OF THE DRY LINE. LOW TO MID LEVEL SHEAR PROFILE LOOKS ADEQUATE FOR SEVERE THUNDERSTORMS ALONG AND AHEAD OF THE DRYLINE. ANOTHER STRONGER SHORTWAVE IS FORECAST BY SATURDAY BY THE GFS, AND A BIT SLOWER ON THE ECMWF RUN. ANOTHER DRYLINE SHOULD FORM AGAIN WITH SUFFICIENT LOW LEVEL MOISTURE AND INSTABILITY FOR ANOTHER ROUND OF THUNDERSTORMS, WITH SOME SEVERE POSSIBLE. LOOK FOR LOWS IN THE MID TO UPPER 40S ON WEDNESDAY INTO THURSDAY NIGHT WITH 50S IN THE EAST BY SATURDAY MORNING AHEAD OF SHORTWAVE TROUGH. HIGHS WILL BE MILD WITH 70S EXCEPT AROUND 80 ON SATURDAY ESPECIALLY BEHIND DRYLINE IN WESTERN KANSAS. && .AVIATION... LOOK FOR VFR CONDITIONS THROUGH THE PERIOD WITH SOME HIGH AND MID CLOUDS COMING IN LATE TONIGHT AND THE CEILING SLOWING FALLING DURING THE DAY ON TUESDAY. A FEW SPRINKLES OR LIGHT SHOWERS WILL ALSO BE POSSIBLE. A COLD FRONT WILL MOVE THROUGH FROM 15 TO 18Z SWITCHING THE WINDS TO NORTHEASTERLY. && .PRELIMINARY POINT TEMPS/POPS... DDC 44 60 42 70 / 0 40 20 0 GCK 43 59 41 71 / 10 30 20 0 EHA 44 60 44 76 / 30 30 20 0 LBL 43 60 41 73 / 20 40 20 0 HYS 44 60 43 68 / 0 30 20 0 P28 46 62 43 69 / 0 50 40 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ FN26/06/06 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 113 PM EDT SUN APR 15 2007 .AVIATION (18Z TAF ISSUANCE)... BACK EDGE OF OVERCAST SKIES NOW PUSHING SOUTH OF THE OHIO RIVER. SOME CU DEVELOPMENT HAS BEEN NOTED IMMEDIATELY BEHIND THE OVERCAST...BUT ONLY EXTENDS SOME 50 MILE N AND W OF THE BACK EDGE. CLEARING LINE WAS ALSO ENTERING THE WESTERN AND SOUTHWEST PORTIONS OF THE FA AS WELL AND WILL CONTINUE TO THE EAST DURING THE AFTERNOON HOURS. FOR THE TAF SITES...CIGS/VSBY WILL REMAIN MVFR FOR THE NEXT COUPLE OF HOURS AT KBWG AND KSDF BEFORE INCREASING TO VFR BY LATE AFTERNOON AND EVENING. KLEX WILL LIKELY REMAIN IN MVFR DUE TO CIGS THROUGH LATE AFTERNOON BEFORE GOING IF LATER TONIGHT. WHERE CLEARING HAS OCCURRED...VERY GOOD MIXING HAS BEEN TAKING PLACE AND WINDS HAVE BEEN GUSTING TO AROUND 30KTS. WILL CONTINUE TO CARRY GUSTY WINDS IN THE TAF SITES THROUGH THE AFTERNOON. WINDS SHOULD BEGIN TO DIE DOWN AS PRESSURE GRADIENT RELAXES TONIGHT. -MJ .MESO UPDATE (THIS AFTERNOON)... MADE A QUICK UPDATE TO THE GRIDS AND ZONES TO ACCOUNT FOR FURTHER SOUTHWARD PROGRESSION OF CLEARING. IN ADDITION...UPSTREAM OBS INDICATE GOOD ATMOSPHERIC MIXING WITH WIND GUSTS APPROACHING 30 MPH IN SOME SPOTS. SO WE HAVE INSERTED THAT WORDING INTO THE TEXT AND GRAPHICAL FORECASTS. BACK EDGE OF THE CLOUDS NOW TAKING ON CLEARING FROM MORE OF A WEST TO EAST. GENERALLY EXPECT THIS TO CONTINUE THROUGH THE AFTERNOON WITH BEST CHANCES OF SUNSHINE GENERALLY ALONG AND WEST OF INTERSTATE 65. SOME PARTIAL CLEARING MAY WORK INTO THE CENTRAL PART OF THE FA BY LATE AFTERNOON AND INTO THE EVENING HOURS. -MJ .MORNING UPDATE (THIS AFTERNOON)... MAIN FORECAST CHALLENGE THIS AFTERNOON WILL REVOLVE AROUND CLOUDS MOVING OUT AND AFTERNOON MAX TEMPERATURES. VISIBLE SATELLITE IMAGERY SHOWING MOSTLY CLEAR SKIES ACROSS CENTRAL INDIANA THIS MORNING. BACK EDGE OF CLOUD SHIELD IS NOW BEGINNING TO WORK ITS WAY INTO OUR FAR NW COUNTIES ATTM. THIS IS IN REASONABLE AGREEMENT WITH THE 12Z RUC LOW-LEVEL RH FIELDS...WHICH SUGGEST ADDITIONAL DRYING IN THE LOW-LEVELS LATER THIS MORNING AND DURING THE AFTERNOON HOURS. ON ITS CURRENT TREK...THE BACK EDGE OF THE CLOUDS SHOULD REACH THE OHIO RIVER AROUND 18-19Z. SOME STRATOCU WILL LIKELY REDEVELOP AFTER INITIAL CLEARING...BUT SHOULD NOT BE OVERLY EXCESSIVE. TEMPERATURES WILL BE MODULATED BY CLOUD COVER TODAY. AS OF RIGHT NOW...THE HIGH TEMPERATURES ACROSS THE SOUTH LOOK A BIT TOO HIGH AS CLOUD COVER WILL LIKELY NOT CLEAR OUT DOWN IN THIS AREA UNTIL LATE AFTERNOON. THEREFORE...PROBABLY WILL ONLY SEE A 5-8 DEGREE RISE FROM CURRENT VALUES FROM BWG NE TO LEX. THUS...WILL TRIM BACK TEMPS A BIT IN THE ZONE UPDATE. CURRENT THINKING IS THAT WHERE WE CLEAR...THOSE LOCALES SHOULD REACH THE UPPER 40S TO AROUND 50. SO IT LOOKS LIKE ANOTHER ONE OF THOSE CLASSIC OHIO VALLEY TEMP GRADIENTS. AS FOR PRECIPITATION...SINCE SUNRISE...WE HAVE SEEN A SLIGHT INCREASE IN THE CLOUD HEIGHTS AND RADAR HAS SHOWN SOME LIGHT RETURNS MAINLY SOUTH OF A LINE FROM HARTFORD TO HARRODSBURG. SO FOR NOW WILL KEEP A SLIGHT CHC OF LGT RAIN IN THE CENTRAL ZONES WITH A SLIGHTLY HIGHER CHANCE ACROSS OUR FAR EAST ZONES THROUGH THE AFTERNOON. PRECIPITATION SHOULD BE WELL EAST OF THE FA BY 00Z TONIGHT. UPDATED GRIDS AND PRODUCTS WILL BE AVAILABLE BY 1100 AM EDT. -MJ .SHORT TERM (TODAY AND TONIGHT)... UPPER AIR PATTERN IS HIGHLY AMPLIFIED AND WILL FORM SOMEWHAT OF AN OMEGA BLOCK OVER THE NEXT COUPLE OF DAYS...WITH DEEP PRACTICALLY CUT-OFF LOWS OVER THE MID ATLANTIC COAST AND THE SOUTHERN ROCKIES. CURRENTLY...THE BASE OF THE EASTERN TROUGH IS MOVING ACROSS THE TENNESSEE VALLEY. THIS WILL BECOME NEGATIVELY TILTED AS IT CATCHES UP WITH AN EXPLOSIVELY DEEPENING COASTAL LOW. BY THIS TIME TOMORROW...THIS EAST COAST STORM WILL BECOME VERTICALLY STACKED NEAR NEW YORK CITY. ACROSS THE LOWER OHIO VALLEY...LOW PRESSURE WILL MOVE EAST OF KENTUCKY LATER THIS MORNING AND DEEPEN RAPIDLY. COLD AIR ADVECTION WILL INCREASE AND NORTHERLY WINDS WILL STRENGTHEN BY LATE MORNING TO 15 TO 20 MPH...WITH GUSTS UP TO 30 MPH. LOW CLOUDS WILL CONTINUE THROUGH EARLY AFTERNOON...IN FACT THE FORECAST SOUNDINGS EVEN DEEPEN THE SATURATION BY LATE MORNING UP TO 13000 FEET ACROSS THE BLUEGRASS REGION AND EASTERN KENTUCKY. THIS...COMBINED WITH A WEAK UPPER AIR DISTURBANCE DIVING SOUTHWARD...MAY GENERATE SOME SPRINKLES OR EVEN A PERIOD OF LIGHT RAIN EAST OF INTERSTATE 65 LATER THIS MORNING OR EARLY AFTERNOON. INITIALLY...THE FORECAST SOUNDINGS HINT AT SOME POSSIBILITY OF A FEW SNOW FLAKES MIXING IN WITH THE RAIN THIS MORNING ACROSS THE BLUEGRASS AND SOUTHERN INDIANA. HOWEVER...SINCE THE SATURATION DEPTH WILL NOT EXTEND INTO THE FAVORABLE TEMPERATURE ZONE FOR SNOW CRYSTAL FORMATION...ANY SNOW OR FLURRIES WILL BE QUITE LIGHT. AS UPPER TROUGH MOVES EAST OF KENTUCKY LATE TOMORROW...LOWER LEVELS WILL UNDERGO SOME DRYING FROM WEST TO EAST LATE THIS AFTERNOON. SKIES MAY BEGIN TO CLEAR AS EARLY AS MID AFTERNOON ALONG OUR WESTERN COUNTIES. OUR EASTERN COUNTIES AND THE BLUEGRASS REGION WILL TAKE MUCH LONGER...BUT SHOULD BE AT LEAST PARTLY CLOUDY BY LATE EVENING. TEMPERATURES WILL BE COLD TONIGHT...WELL INTO THE MID 30S ACROSS THE BLUEGRASS...BUT WITH THE BOUNDARY LAYER STAYING MIXED AND SUSTAINED NORTH WINDS CONTINUING AROUND 10 MPH MONDAY MORNING...FEEL THAT WIDESPREAD FROST IS UNLIKELY. JSD .LONG TERM... (MONDAY THROUGH WEDNESDAY) A DEEP MID ATLANTIC COAST CLOSED LOW WILL BRING HAVOC TO THE NORTHEAST SEABOARD BUT WILL ONLY PRODUCE A COOL NORTHERLY FLOW ACROSS THE LOWER OHIO VALLEY MONDAY AND TUESDAY. PARTLY CLOUDY SKIES EARLY MONDAY WILL GIVE WAY TO CLEARING BY MID DAY WITH CLEAR SKIES EXPECTED THROUGH TUESDAY AFTERNOON. TEMPERATURES MONDAY WILL REMAIN SOME 10 TO 15 DEGREES BELOW NORMAL BUT SHOULD WARM NICELY TUESDAY INTO THE LOW AND MID 60S. A WEAK UPPER LEVEL DISTURBANCE WILL DROP INTO THE REGION WEDNESDAY. THE SHORT RANGE FORECAST MODELS DIFFER ON THE STRENGTH AND LOCATION SO WE WILL KEEP LOW POPS IN THE FORECAST. RAINFALL SHOULD REMAIN SCATTERED AND BRIEF. THE CLOUD COVER AND REINFORCING COOL AIR TEMPERATURES WILL CUT HIGHS SOME AROUND 5 DEGREES FROM TUESDAY. (THURSDAY THROUGH SATURDAY)... AS THE FORE MENTIONED UPPER LOW MOVES OFF THE EAST COAST A RIDGE WILL BUILD INTO THE REGION AS ANOTHER DEEP LOW DIGS INTO THE WESTERN STATES. FOR THE FORECAST AREA THIS WILL MEAN SEVERAL DAYS OF MOSTLY CLEAR SKIES AND TEMPERATURES AT OR ABOVE NORMAL. FOR ALL THOSE PLANNING OUTDOOR ACTIVITIES SATURDAY TEMPERATURE SHOULD TOP OUT IN THE UPPER 60S AND LOWER 70S. JA && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1241 PM EDT SUN APR 15 2007 .MESO UPDATE (THIS AFTERNOON)... MADE A QUICK UPDATE TO THE GRIDS AND ZONES TO ACCOUNT FOR FURTHER SOUTHWARD PROGRESSION OF CLEARING. IN ADDITION...UPSTREAM OBS INDICATE GOOD ATMOSPHERIC MIXING WITH WIND GUSTS APPROACHING 30 MPH IN SOME SPOTS. SO WE HAVE INSERTED THAT WORDING INTO THE TEXT AND GRAPHICAL FORECASTS. BACK EDGE OF THE CLOUDS NOW TAKING ON CLEARING FROM MORE OF A WEST TO EAST. GENERALLY EXPECT THIS TO CONTINUE THROUGH THE AFTERNOON WITH BEST CHANCES OF SUNSHINE GENERALLY ALONG AND WEST OF INTERSTATE 65. SOME PARTIAL CLEARING MAY WORK INTO THE CENTRAL PART OF THE FA BY LATE AFTERNOON AND INTO THE EVENING HOURS. -MJ .MORNING UPDATE (THIS AFTERNOON)... MAIN FORECAST CHALLENGE THIS AFTERNOON WILL REVOLVE AROUND CLOUDS MOVING OUT AND AFTERNOON MAX TEMPERATURES. VISIBLE SATELLITE IMAGERY SHOWING MOSTLY CLEAR SKIES ACROSS CENTRAL INDIANA THIS MORNING. BACK EDGE OF CLOUD SHIELD IS NOW BEGINNING TO WORK ITS WAY INTO OUR FAR NW COUNTIES ATTM. THIS IS IN REASONABLE AGREEMENT WITH THE 12Z RUC LOW-LEVEL RH FIELDS...WHICH SUGGEST ADDITIONAL DRYING IN THE LOW-LEVELS LATER THIS MORNING AND DURING THE AFTERNOON HOURS. ON ITS CURRENT TREK...THE BACK EDGE OF THE CLOUDS SHOULD REACH THE OHIO RIVER AROUND 18-19Z. SOME STRATOCU WILL LIKELY REDEVELOP AFTER INITIAL CLEARING...BUT SHOULD NOT BE OVERLY EXCESSIVE. TEMPERATURES WILL BE MODULATED BY CLOUD COVER TODAY. AS OF RIGHT NOW...THE HIGH TEMPERATURES ACROSS THE SOUTH LOOK A BIT TOO HIGH AS CLOUD COVER WILL LIKELY NOT CLEAR OUT DOWN IN THIS AREA UNTIL LATE AFTERNOON. THEREFORE...PROBABLY WILL ONLY SEE A 5-8 DEGREE RISE FROM CURRENT VALUES FROM BWG NE TO LEX. THUS...WILL TRIM BACK TEMPS A BIT IN THE ZONE UPDATE. CURRENT THINKING IS THAT WHERE WE CLEAR...THOSE LOCALES SHOULD REACH THE UPPER 40S TO AROUND 50. SO IT LOOKS LIKE ANOTHER ONE OF THOSE CLASSIC OHIO VALLEY TEMP GRADIENTS. AS FOR PRECIPITATION...SINCE SUNRISE...WE HAVE SEEN A SLIGHT INCREASE IN THE CLOUD HEIGHTS AND RADAR HAS SHOWN SOME LIGHT RETURNS MAINLY SOUTH OF A LINE FROM HARTFORD TO HARRODSBURG. SO FOR NOW WILL KEEP A SLIGHT CHC OF LGT RAIN IN THE CENTRAL ZONES WITH A SLIGHTLY HIGHER CHANCE ACROSS OUR FAR EAST ZONES THROUGH THE AFTERNOON. PRECIPITATION SHOULD BE WELL EAST OF THE FA BY 00Z TONIGHT. UPDATED GRIDS AND PRODUCTS WILL BE AVAILABLE BY 1100 AM EDT. -MJ .SHORT TERM (TODAY AND TONIGHT)... UPPER AIR PATTERN IS HIGHLY AMPLIFIED AND WILL FORM SOMEWHAT OF AN OMEGA BLOCK OVER THE NEXT COUPLE OF DAYS...WITH DEEP PRACTICALLY CUT-OFF LOWS OVER THE MID ATLANTIC COAST AND THE SOUTHERN ROCKIES. CURRENTLY...THE BASE OF THE EASTERN TROUGH IS MOVING ACROSS THE TENNESSEE VALLEY. THIS WILL BECOME NEGATIVELY TILTED AS IT CATCHES UP WITH AN EXPLOSIVELY DEEPENING COASTAL LOW. BY THIS TIME TOMORROW...THIS EAST COAST STORM WILL BECOME VERTICALLY STACKED NEAR NEW YORK CITY. ACROSS THE LOWER OHIO VALLEY...LOW PRESSURE WILL MOVE EAST OF KENTUCKY LATER THIS MORNING AND DEEPEN RAPIDLY. COLD AIR ADVECTION WILL INCREASE AND NORTHERLY WINDS WILL STRENGTHEN BY LATE MORNING TO 15 TO 20 MPH...WITH GUSTS UP TO 30 MPH. LOW CLOUDS WILL CONTINUE THROUGH EARLY AFTERNOON...IN FACT THE FORECAST SOUNDINGS EVEN DEEPEN THE SATURATION BY LATE MORNING UP TO 13000 FEET ACROSS THE BLUEGRASS REGION AND EASTERN KENTUCKY. THIS...COMBINED WITH A WEAK UPPER AIR DISTURBANCE DIVING SOUTHWARD...MAY GENERATE SOME SPRINKLES OR EVEN A PERIOD OF LIGHT RAIN EAST OF INTERSTATE 65 LATER THIS MORNING OR EARLY AFTERNOON. INITIALLY...THE FORECAST SOUNDINGS HINT AT SOME POSSIBILITY OF A FEW SNOW FLAKES MIXING IN WITH THE RAIN THIS MORNING ACROSS THE BLUEGRASS AND SOUTHERN INDIANA. HOWEVER...SINCE THE SATURATION DEPTH WILL NOT EXTEND INTO THE FAVORABLE TEMPERATURE ZONE FOR SNOW CRYSTAL FORMATION...ANY SNOW OR FLURRIES WILL BE QUITE LIGHT. AS UPPER TROUGH MOVES EAST OF KENTUCKY LATE TOMORROW...LOWER LEVELS WILL UNDERGO SOME DRYING FROM WEST TO EAST LATE THIS AFTERNOON. SKIES MAY BEGIN TO CLEAR AS EARLY AS MID AFTERNOON ALONG OUR WESTERN COUNTIES. OUR EASTERN COUNTIES AND THE BLUEGRASS REGION WILL TAKE MUCH LONGER...BUT SHOULD BE AT LEAST PARTLY CLOUDY BY LATE EVENING. TEMPERATURES WILL BE COLD TONIGHT...WELL INTO THE MID 30S ACROSS THE BLUEGRASS...BUT WITH THE BOUNDARY LAYER STAYING MIXED AND SUSTAINED NORTH WINDS CONTINUING AROUND 10 MPH MONDAY MORNING...FEEL THAT WIDESPREAD FROST IS UNLIKELY. JSD .LONG TERM... (MONDAY THROUGH WEDNESDAY) A DEEP MID ATLANTIC COAST CLOSED LOW WILL BRING HAVOC TO THE NORTHEAST SEABOARD BUT WILL ONLY PRODUCE A COOL NORTHERLY FLOW ACROSS THE LOWER OHIO VALLEY MONDAY AND TUESDAY. PARTLY CLOUDY SKIES EARLY MONDAY WILL GIVE WAY TO CLEARING BY MID DAY WITH CLEAR SKIES EXPECTED THROUGH TUESDAY AFTERNOON. TEMPERATURES MONDAY WILL REMAIN SOME 10 TO 15 DEGREES BELOW NORMAL BUT SHOULD WARM NICELY TUESDAY INTO THE LOW AND MID 60S. A WEAK UPPER LEVEL DISTURBANCE WILL DROP INTO THE REGION WEDNESDAY. THE SHORT RANGE FORECAST MODELS DIFFER ON THE STRENGTH AND LOCATION SO WE WILL KEEP LOW POPS IN THE FORECAST. RAINFALL SHOULD REMAIN SCATTERED AND BRIEF. THE CLOUD COVER AND REINFORCING COOL AIR TEMPERATURES WILL CUT HIGHS SOME AROUND 5 DEGREES FROM TUESDAY. (THURSDAY THROUGH SATURDAY)... AS THE FORE MENTIONED UPPER LOW MOVES OFF THE EAST COAST A RIDGE WILL BUILD INTO THE REGION AS ANOTHER DEEP LOW DIGS INTO THE WESTERN STATES. FOR THE FORECAST AREA THIS WILL MEAN SEVERAL DAYS OF MOSTLY CLEAR SKIES AND TEMPERATURES AT OR ABOVE NORMAL. FOR ALL THOSE PLANNING OUTDOOR ACTIVITIES SATURDAY TEMPERATURE SHOULD TOP OUT IN THE UPPER 60S AND LOWER 70S. JA && .AVIATION (12Z TAFS)... NORTH WINDS WILL INCREASE THIS AFTERNOON TO 10 TO 20 MPH WITH WIND GUSTS UP TO 25 MPH. LIFR CEILINGS AT LEX AND BWG WILL LIFT TO IFR STATUS BY 14Z...WHILE CEILINGS AT SDF REMAIN IFR. A WEAK DISTURBANCE WILL MOVE SOUTH TOWARDS KENTUCKY LATER THIS MORNING. THIS WILL INCREASE DEPTH OF MOIST LOW LAYERS AT LEX AND MAY PRODUCE A FEW SPRINKLES OR LIGHT RAIN SHOWERS BY LATE THIS MORNING. CEILINGS HOWEVER WILL TREND HIGHER TOWARDS THE AFTERNOON...LIFTING TO 1 TO 3 THOUSAND FEET. PARTIAL CLEARING IS EXPECTED AT SDF AND BWG LATE THIS AFTERNOON...WITH LEXINGTON CLEARING OUT LAST. JSD && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1030 AM EDT SUN APR 15 2007 .MORNING UPDATE (THIS AFTERNOON)... MAIN FORECAST CHALLENGE THIS AFTERNOON WILL REVOLVE AROUND CLOUDS MOVING OUT AND AFTERNOON MAX TEMPERATURES. VISIBLE SATELLITE IMAGERY SHOWING MOSTLY CLEAR SKIES ACROSS CENTRAL INDIANA THIS MORNING. BACK EDGE OF CLOUD SHIELD IS NOW BEGINNING TO WORK ITS WAY INTO OUR FAR NW COUNTIES ATTM. THIS IS IN REASONABLE AGREEMENT WITH THE 12Z RUC LOW-LEVEL RH FIELDS...WHICH SUGGEST ADDITIONAL DRYING IN THE LOW-LEVELS LATER THIS MORNING AND DURING THE AFTERNOON HOURS. ON ITS CURRENT TREK...THE BACK EDGE OF THE CLOUDS SHOULD REACH THE OHIO RIVER AROUND 18-19Z. SOME STRATOCU WILL LIKELY REDEVELOP AFTER INITIAL CLEARING...BUT SHOULD NOT BE OVERLY EXCESSIVE. TEMPERATURES WILL BE MODULATED BY CLOUD COVER TODAY. AS OF RIGHT NOW...THE HIGH TEMPERATURES ACROSS THE SOUTH LOOK A BIT TOO HIGH AS CLOUD COVER WILL LIKELY NOT CLEAR OUT DOWN IN THIS AREA UNTIL LATE AFTERNOON. THEREFORE...PROBABLY WILL ONLY SEE A 5-8 DEGREE RISE FROM CURRENT VALUES FROM BWG NE TO LEX. THUS...WILL TRIM BACK TEMPS A BIT IN THE ZONE UPDATE. CURRENT THINKING IS THAT WHERE WE CLEAR...THOSE LOCALES SHOULD REACH THE UPPER 40S TO AROUND 50. SO IT LOOKS LIKE ANOTHER ONE OF THOSE CLASSIC OHIO VALLEY TEMP GRADIENTS. AS FOR PRECIPITATION...SINCE SUNRISE...WE HAVE SEEN A SLIGHT INCREASE IN THE CLOUD HEIGHTS AND RADAR HAS SHOWN SOME LIGHT RETURNS MAINLY SOUTH OF A LINE FROM HARTFORD TO HARRODSBURG. SO FOR NOW WILL KEEP A SLIGHT CHC OF LGT RAIN IN THE CENTRAL ZONES WITH A SLIGHTLY HIGHER CHANCE ACROSS OUR FAR EAST ZONES THROUGH THE AFTERNOON. PRECIPITATION SHOULD BE WELL EAST OF THE FA BY 00Z TONIGHT. UPDATED GRIDS AND PRODUCTS WILL BE AVAILABLE BY 1100 AM EDT. -MJ .SHORT TERM (TODAY AND TONIGHT)... UPPER AIR PATTERN IS HIGHLY AMPLIFIED AND WILL FORM SOMEWHAT OF AN OMEGA BLOCK OVER THE NEXT COUPLE OF DAYS...WITH DEEP PRACTICALLY CUT-OFF LOWS OVER THE MID ATLANTIC COAST AND THE SOUTHERN ROCKIES. CURRENTLY...THE BASE OF THE EASTERN TROUGH IS MOVING ACROSS THE TENNESSEE VALLEY. THIS WILL BECOME NEGATIVELY TILTED AS IT CATCHES UP WITH AN EXPLOSIVELY DEEPENING COASTAL LOW. BY THIS TIME TOMORROW...THIS EAST COAST STORM WILL BECOME VERTICALLY STACKED NEAR NEW YORK CITY. ACROSS THE LOWER OHIO VALLEY...LOW PRESSURE WILL MOVE EAST OF KENTUCKY LATER THIS MORNING AND DEEPEN RAPIDLY. COLD AIR ADVECTION WILL INCREASE AND NORTHERLY WINDS WILL STRENGTHEN BY LATE MORNING TO 15 TO 20 MPH...WITH GUSTS UP TO 30 MPH. LOW CLOUDS WILL CONTINUE THROUGH EARLY AFTERNOON...IN FACT THE FORECAST SOUNDINGS EVEN DEEPEN THE SATURATION BY LATE MORNING UP TO 13000 FEET ACROSS THE BLUEGRASS REGION AND EASTERN KENTUCKY. THIS...COMBINED WITH A WEAK UPPER AIR DISTURBANCE DIVING SOUTHWARD...MAY GENERATE SOME SPRINKLES OR EVEN A PERIOD OF LIGHT RAIN EAST OF INTERSTATE 65 LATER THIS MORNING OR EARLY AFTERNOON. INITIALLY...THE FORECAST SOUNDINGS HINT AT SOME POSSIBILITY OF A FEW SNOW FLAKES MIXING IN WITH THE RAIN THIS MORNING ACROSS THE BLUEGRASS AND SOUTHERN INDIANA. HOWEVER...SINCE THE SATURATION DEPTH WILL NOT EXTEND INTO THE FAVORABLE TEMPERATURE ZONE FOR SNOW CRYSTAL FORMATION...ANY SNOW OR FLURRIES WILL BE QUITE LIGHT. AS UPPER TROUGH MOVES EAST OF KENTUCKY LATE TOMORROW...LOWER LEVELS WILL UNDERGO SOME DRYING FROM WEST TO EAST LATE THIS AFTERNOON. SKIES MAY BEGIN TO CLEAR AS EARLY AS MID AFTERNOON ALONG OUR WESTERN COUNTIES. OUR EASTERN COUNTIES AND THE BLUEGRASS REGION WILL TAKE MUCH LONGER...BUT SHOULD BE AT LEAST PARTLY CLOUDY BY LATE EVENING. TEMPERATURES WILL BE COLD TONIGHT...WELL INTO THE MID 30S ACROSS THE BLUEGRASS...BUT WITH THE BOUNDARY LAYER STAYING MIXED AND SUSTAINED NORTH WINDS CONTINUING AROUND 10 MPH MONDAY MORNING...FEEL THAT WIDESPREAD FROST IS UNLIKELY. JSD .LONG TERM... (MONDAY THROUGH WEDNESDAY) A DEEP MID ATLANTIC COAST CLOSED LOW WILL BRING HAVOC TO THE NORTHEAST SEABOARD BUT WILL ONLY PRODUCE A COOL NORTHERLY FLOW ACROSS THE LOWER OHIO VALLEY MONDAY AND TUESDAY. PARTLY CLOUDY SKIES EARLY MONDAY WILL GIVE WAY TO CLEARING BY MID DAY WITH CLEAR SKIES EXPECTED THROUGH TUESDAY AFTERNOON. TEMPERATURES MONDAY WILL REMAIN SOME 10 TO 15 DEGREES BELOW NORMAL BUT SHOULD WARM NICELY TUESDAY INTO THE LOW AND MID 60S. A WEAK UPPER LEVEL DISTURBANCE WILL DROP INTO THE REGION WEDNESDAY. THE SHORT RANGE FORECAST MODELS DIFFER ON THE STRENGTH AND LOCATION SO WE WILL KEEP LOW POPS IN THE FORECAST. RAINFALL SHOULD REMAIN SCATTERED AND BRIEF. THE CLOUD COVER AND REINFORCING COOL AIR TEMPERATURES WILL CUT HIGHS SOME AROUND 5 DEGREES FROM TUESDAY. (THURSDAY THROUGH SATURDAY)... AS THE FORE MENTIONED UPPER LOW MOVES OFF THE EAST COAST A RIDGE WILL BUILD INTO THE REGION AS ANOTHER DEEP LOW DIGS INTO THE WESTERN STATES. FOR THE FORECAST AREA THIS WILL MEAN SEVERAL DAYS OF MOSTLY CLEAR SKIES AND TEMPERATURES AT OR ABOVE NORMAL. FOR ALL THOSE PLANNING OUTDOOR ACTIVITIES SATURDAY TEMPERATURE SHOULD TOP OUT IN THE UPPER 60S AND LOWER 70S. JA && .AVIATION (12Z TAFS)... NORTH WINDS WILL INCREASE THIS AFTERNOON TO 10 TO 20 MPH WITH WIND GUSTS UP TO 25 MPH. LIFR CEILINGS AT LEX AND BWG WILL LIFT TO IFR STATUS BY 14Z...WHILE CEILINGS AT SDF REMAIN IFR. A WEAK DISTURBANCE WILL MOVE SOUTH TOWARDS KENTUCKY LATER THIS MORNING. THIS WILL INCREASE DEPTH OF MOIST LOW LAYERS AT LEX AND MAY PRODUCE A FEW SPRINKLES OR LIGHT RAIN SHOWERS BY LATE THIS MORNING. CEILINGS HOWEVER WILL TREND HIGHER TOWARDS THE AFTERNOON...LIFTING TO 1 TO 3 THOUSAND FEET. PARTIAL CLEARING IS EXPECTED AT SDF AND BWG LATE THIS AFTERNOON...WITH LEXINGTON CLEARING OUT LAST. JSD && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1104 AM EDT SUN APR 15 2007 .SHORT TERM /REST OF TODAY/... LOPRES IN WRN NC ATTM...MVG NE. ALNG THE METRO CORRIDOR...THERE HV BEEN SVRL ATTEMPTS AT A DRY SLOT...EACH OF WHICH HAS FILLED IN. SOLID STREAM OF MSTR UP THE SPINE OF THE PTMC HIGHLANDS THO. WL MAKE NO CHGS TO THE FAA...ALTHO MOST OF THAT AREA ALREADY HAS ACTV FLW. ALSO FLWS FOR MOST OF THE PTMC HIGHLANDS. SEE SPECIFIC STMTS FOR VALID TIMES AND DETAILS. RGNL MOSAIC INDICATES THAT BACK EDGE SVRL HRS AWAY. EVEN A LTL ENHANCEMENT IN RAFL RATES THX TO CNVCTV ELEMENTS. RUC/NAM INSIST THAT HVYST RAFL WL BE IN THE I-95 CORRIDOR BTWN DC-BALT. WL BLEND RADAR AND GDNC. OVRALL THEME WL BE TO SLOW DOWN THE ENDING TIME OF THE PCPN. FEW OTR CHGS TO GRIDS ATTM. RUNNING LATE. UPDTS OUT ASAP. && .AVIATION /15Z-12Z/... IFR/LIFR CIGS AND IFR VSBYS ATTM. IMPVMNT COMES TNGT ONCE LOPRES CLEARS AREA. && .MARINE... TPLM2 AT STRONG SCA. MOST OTR SITES MARGINAL AT BEST. STILL A POWERFUL CYCLONE HEADING THIS WAY /992 MB IN WRN NC/...SO WL RIDE OUT ANY LULL. ALL HEADLINES CONTINUE. && .PREV DISCUSSION... /ISSUED 405 AM EDT SUN APR 15 2007/ SHORT TERM (TODAY THROUGH TONIGHT)... WATER VAPOR LOOP SHOWS A WAVE MOVING INTO THE TENNESSEE VALLEY AS A SECOND SHORT WAVE DROPS SOUTH INTO THE MIDWEST. ACARS 400-250MB WIND OBSERVATIONS REVEAL A POSITIVELY TILTED UPPER LEVEL TROUGH ACROSS THE MIDDLE MISSISSIPPI RIVER VALLEY...WITH A 120-160KT SOUTHWESTERLY JET EXTENDING FROM THE PLAINS THROUGH THE EASTERN GREAT LAKES. 03Z SURFACE ANALYSIS PLACED A 1001MB CYCLONE IN EASTERN KENTUCKY...ALONG THE NEXT COLD FRONT. A WARM FRONT EXTENDED NORTHEAST FROM A 1002MB CYCLONE IN EAST CENTRAL ALABAMA THROUGH CENTRAL NORTH CAROLINA. ACARS UPPER LEVEL WIND DATA HAS BEEN ABLE TO SHOW A SUBTLE 120-140KT SOUTHWESTERLY JETLET ACROSS THE EASTERN GREAT LAKES. PRECIPITATION ACROSS THE OHIO VALLEY LINES UP WELL WHERE JET COUPLING SEEMS TO BE OCCURRING. THE FLIP SIDE TO THIS IS THE DEVELOPMENT OF A DRY SLOT (DRAWN IN FROM BACKSIDE OF SOUTHEAST CONUS CONVECTION) OVERHEAD. AS THE JETLET ACROSS THE EASTERN GREAT LAKES MOVES AWAY FROM THE REGION...EXPECT RESULTANT VERTICAL CIRCULATIONS TO DIMINISH. MEANWHILE...5MB PRESSURE FALLS HAVE BEEN OCCURRING ACROSS CENTRAL VIRGINIA BETWEEN 3-6Z. THERE IS STILL A DYNAMIC SITUATION ACROSS THE REGION...EVIDENCED BY SHOWER AND THUNDERSTORM REDEVELOPMENT WITHIN THE DRYSLOT DURING THE PAST SEVERAL HOURS. ISENTROPIC LIFT OVER THE WARM FRONT TO THE SOUTHEAST WILL PERSIST THROUGH THE MORNING...WHICH SHOULD LEAD TO THE REDEVELOPMENT OF MODERATE TO HEAVY RAIN ACROSS THE REGION. WHILE 00Z MODEL SUITE (ESPECIALLY GFS AND KLWX WRF-NMM) DID NOT CLEARLY INDICATE BREAK IN PRECIPITATION...OBSERVATIONAL TRENDS DO SUPPORT MODEL INDICATIONS OF RAIN AXIS DURING THE MORNING HOURS. RAIN PROCESS WILL BE EFFICIENT THIS MORNING...OWING TO WARM CLOUD DEPTH UP TO 15KFT (-5C LEVEL)...PRECIPITABLE WATER VALUES GREATER THAN 2 STANDARD DEVIATIONS ABOVE CLIMATOLOGY...AND AMOUNT OF LOW LEVEL FORCING ASSOCIATED WITH FRONTOGENESIS. WARM FRONT MAY LIFT INTO SOUTHEAST ZONES THIS MORNING...WHERE WARMEST HIGHS ARE INDICATED. COLD ADVECTION WILL BEGIN DURING THE MID AFTERNOON IN THE HIGHER TERRAIN...WHERE COOLING TEMPERATURES MAY SUPPORT SNOW SHOWERS MIXING IN WITH RAIN. TONIGHT WILL BE A TRANSITION PERIOD. AS THE COASTAL STORM DEEPENS WITHIN THE NEW ENGLAND WATERS...PRESSURE/HEIGHT GRADIENT WILL SUPPORT STRENGTHENING NORTHWEST WIND GUSTS. WHILE UPPER LOW WILL BE NEARBY...EXPECT DRYING BOUNDARY LAYER TO CONTRIBUTE TO DRYING CONDITIONS EAST OF THE MOUNTAINS DURING THE NIGHT. ACROSS THE UPSLOPE AREAS...00Z NAM AND 21Z SHORT RANGE ENSEMBLES INDICATE POSSIBILITY OF 1-3 INCHES OF SNOW. WILL HAVE TO MONITOR PAN HANDLE REGION OF WEST VIRGINIA AND MARYLAND...WITH SUCH STRONG FLOW...SHOWERS MAY MAKE IT TO THE BLUE RIDGE. HAVE WARMED UP MOS GUIDANCE TONIGHT GIVEN GUSTY NORTHWEST FLOW. TEMPERATURES WILL BE CLOSE TO A FREEZE WARNING CRITERIA IN THE HIGHER TERRAIN ALONG AND WEST OF THE BLUE RIDGE...BUT CONFIDENCE NOT HIGH ENOUGH TO WARRANT A WATCH FOR SUCH A SMALL AREA. AVIATION... MODERATE TO HEAVY RAIN AXIS EXPECTED TO DEVELOP OVER TERMINALS EARLY THIS MORNING...CONTINUING TO SUPPORT LIFR-IFR CEILINGS/VISIBILITIES. DOWNSLOPE COMPONENT INCREASES THIS AFTERNOON...ALLOWING FOR IMPROVEMENT. GRADIENT BEHIND DEEPENING COASTAL STORM WILL SUPPORT GUSTY NORTHWEST WINDS THIS EVENING AND OVERNIGHT. MARINE... 00Z GFS/ETA MOS AT THOMAS POINT INDICATE SUSTAINED WINDS 25KTS EARLY THIS MORNING....DECREASING TO 15-20KTS THIS AFTERNOON...BEFORE INCREASING BACK TO 25KTS TONIGHT. 00Z NAM/GFS PROXIMITY BUFKIT FORECAST SOUNDINGS INDICATE WIND GUSTS NEARING GALES AFTER MIDNIGHT. GALE CONDITIONS EXPECTED FOR MON INTO MON EVENING. EXPECT NW WINDS OF NEAR SMALL CRAFT TO CONTINUE OVERNIGHT MON NIGHT THROUGH TUE. WINDS WILL SLACKEN ON WED AND THUR AS WEAK HIGH PRES OVER THE GREAT LAKES BUILDS ACROSS THE REGION. TIDES... WATER LEVELS ARE CURRENTLY LESS THAN A HALF FOOT BELOW ASTRONOMICAL PREDICTIONS. THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND NOAA EXTRATROPICAL STORM SURGE MODEL INDICATE WATER LEVELS WILL RISE TO ABOUT A FOOT ABOVE ASTRONOMICAL PREDICTIONS THIS MORNING. THE LUNAR PHASE IS WANING TOWARD A NEW MOON (7% FULL). WATER LEVELS WILL HAVE TO BE MONITORED THIS MORNING AS STRONG SOUTHEAST FLOW IS EXPECTED ALLOW POSITIVE TIDAL DEPARTURES TO DEVELOP. DO NOT EXPECT DEPARTURES TO RISE ABOVE NUISANCE COASTAL FLOOD LEVELS GIVEN THE SPEED OF THE SYSTEM. EXPECT BLOWOUT CONDITIONS TO DEVELOP TONIGHT INTO EARLY NEXT WEEK AS THE DEEP COASTAL STORM MOVES OFFSHORE. LONG TERM /MONDAY THROUGH SATURDAY/... DEEP LOW PRESSURE WILL BRING DREARY AND UNSEASONABLY COLD CONTINUES THROUGH THURS THEN A MODERATION OF TEMPERATURES BEGINS TOWARDS THE WEEKEND. AN UNSEASONABLY DEEP SURFACE LOW PRESSURE CENTER IS PROGGED TO BE LOCATED SOMEWHERE NEAR NYC. BASED UPON 21Z/14 SREFS CENTRAL PRESSURE WILL BE 979MB BY 12Z MON. THE 00Z GFS HAS IT DOWN TO 974 MB. BY NOON ON MON THE LOW BECOMES NEARLY VERTICALLY STACKED WITH THE UPPER LEVELS AND BEGINS TO FILL. THE LOW WILL DRIFT EAST AND AWAY FROM THE AREA ON TUE AND WED...THEN HIGH PRESSURE WILL BUILD ACROSS THE REGION FOR THE LATER PART OF THE WEEK. FOR SATURDAY THE HIGH NESTLES OVER THE MID ATLANTIC REGION AND PERHAPS GIVES THE AREA ANOTHER TASTE OF SPRING. FOR MON...TWO CONCERNS: WINDS AND UPSLOPE SNOW. A VERY TIGHT SURFACE PRESSURE GRADIENT AND STRONG LOW-LEVEL CYCLONIC FLOW AROUND THE LOW OVER SOUTHERN NY WILL DOMINATE THE WEATHER. STRONG AND GUSTY NORTHWEST WINDS ACCROSS THE REGION WILL LIKELY APPROACH WIND ADVISORY CONDITIONS BUT WILL NOT BE STRONG ENOUGH TO WARRANT ANY TYPE OF HIGH WIND WARCH. THE OTHER CONCERN WILL BE THE CONTINUATION OF ACCUMULATING SNOW IN THE FAR WESTERN ZONES IN UPSLOPE PORTIONS. FOR MON NIGHT...COLD TEMPS ONCE AGAIN ARE FORECAST...WITH SOME SPOTS ALONG AND TO THE WEST OF THE BLUE RIDGE EXPECTED TO DROP TO NEAR FREEZING. HOWEVER...STRONG NW CYCLONIC FLOW WILL STILL BE WITH US WHICH WLL HELP MINIMZIE THREAT OF WIDESPREAD FREEZING CONDITIONS. FOR TUE...GRADUAL DRYING AND ABATEMENT OF WINDS AS THE SURFACE LOW PUSHES OUT TO SEA. FOR WED TO SAT...HIGH PRES OVER THE GREAT LAKES ON WED WILL MOVE SLOWLY EAST TO A POSITION OVER THE MID ATLANTIC BY LATE FRI. DID NOT MAKE SIGNIFICANT CHANGES IN THIS PART OF THE LONG TERM...AND CONTINUED WITH DRY WEATHER AND GRADUAL MODERATION IN TEMPS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...FLOOD WATCH UNTIL 4 PM EDT THIS AFTERNOON FOR DCZ001. MD...FLOOD WATCH UNTIL 4 PM EDT THIS AFTERNOON FOR MDZ004>007- 009>011-013-014-016>018. WINTER STORM WATCH FROM 8 PM EDT THIS EVENING THROUGH MONDAY MORNING FOR MDZ501. VA...FLOOD WATCH UNTIL 4 PM EDT THIS AFTERNOON FOR VAZ036>042- 050>057. WV...WINTER STORM WATCH FROM 8 PM EDT THIS EVENING THROUGH MONDAY MORNING FOR WVZ501-503. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT MONDAY FOR ANZ530>537. GALE WARNING FROM 4 AM TO 11 PM EDT MONDAY FOR ANZ530>537. && $$ SHORT TERM/AVIATION/MARINE...HTS PREVIOUS DISCUSSION...ROGOWSKI/SMZ md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 406 PM EDT MON APR 16 2007 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR RAIN TONIGHT. WATER VAPOR IMAGERY AND RUC SHOWING DEEP CUTOFF LOW OVER KNYC ...ANOTHER CUTOFF LOW OVER SOUTHWEST ARIZONA...AND AN OMEGA BLOCK OVER THE CENTRAL AND NORTHERN PLAINS SEPARATING THESE TWO LOWS. A RIDGE WHICH IS PART OF THE RIDGE EXTENDS ACROSS THE WESTERN LAKE SUPERIOR. A SHORTWAVE NAVIGATING THROUGH THIS RIDGE IS OVER EASTERN NORTH DAKOTA AND SOUTHEAST MANITOBA. THE SURFACE ANALYSIS INSIST ON A NARROW RIDGE STRETCHING FROM JAMES BAY ACROSS UPPER MICHIGAN TO A RIDGE OVER CENTRAL MISSISSIPPI RIVER VALLEY. A COLD FRONT EXTENDS FROM A LOW OVER CENTRAL HUDSON BAY THROUGH THE ARROWHEAD OF MINNESOTA TO A LOW OVER WESTERN KANSAS. A 1020MB HIGH CONTINUES TO BUILD OVER MANITOBA PUSHING THIS FRONT ALONG. THE SHORTWAVE WILL MOVE INTO WESTERN UPPER MICHIGAN TONIGHT. THE WEAK COLD FRONT WILL SLIDE INTO INTO WESTERN U.P. ISENTROPIC ASCENT WITH THE FRONT AND SHORTWAVE ENERGY WILL GENERATE SOME RAIN OVER THE AREA...FED BY THE NARROW BAND OF DEEP MOISTURE. PLAN TO TRACK THIS MOISTURE AND WEAK COLD FRONT THROUGH THE U.P. FOR AREAS OF RAIN ON TUESDAY. LITTLE OR NO CAPE IS INDICATED AND THE LI`S WILL BE 8 TO 14. THE UPPER LEVEL JET MAX WILL BE WELL TO THE SOUTH OF THE FORECAST AREA. THUS DO NOT THINK THERE WILL BE ANY THUNDER WITH THIS ACTIVITY. DRY AIR WILL ADVECT INTO THE AREA RAPIDLY FROM THE WEST. NAM/GFS SHOWING RAPID DRYING BY LATE MORNING. ANOTHER SHORTWAVE WILL SHIFT ACROSS THE FORECAST AREA LATE TUESDAY NIGHT. NAM/GFS SHOWING DEEP MOISTURE SPREADING INTO THE AREA FROM THE WEST. THERE WILL BE VERY LITTLE SURFACE SUPPORT FOR ANY PRECIPITATION. WILL ADD A CHANCE LATE OVER THE FAR EAST. TWO WEAK SHORTWAVE WILL PASS OVER EASTERN U.P. ON WEDNESDAY. NAM/GFS SHOWING DEEP MOISTURE BACKING INTO THE WEST END OF THE U.P. DIVERGENCE ASSOCIATED WITH UPPER LEVEL JET WILL ENHANCE THE POTENTIAL FOR SHOWERS DEVELOPING MAINLY OVER THE EASTERN U.P. THE STRONGEST UPPER LEVEL JET WILL REMAIN SOUTH OF THE FORECAST AREA...SO DON`T EXPECT TO SEE ANY THUNDERSTORMS WITH THIS SYSTEM. AND LI`S WILL REMAIN AROUND 20. THE SURFACE RIDGE WILL NAVIGATE INTO THE FORECAST AREA ON WEDNESDAY. THE SURFACE RIDGE WILL SHIFT OVER THE FORECAST AREA ON WEDNESDAY AND THURSDAY. THERE WILL STILL BE AREAS OF MID LEVEL MOISTURE. HOWEVER...THE SHORTWAVE ENERGY IS EXPECTED TO BE EAST OF THE FORECAST AREA...SO WILL KEEP THE CONDITIONS DRY FOR NOW. THE SURFACE AND UPPER LEVEL RIDGE WILL REMAIN IN PLACE OVER THE FORECAST AREA THROUGH THURSDAY. THE OMEGA BLOCK OVER ONTARIO AND THE GREAT LAKES WILL CONTINUE THURSDAY NIGHT AND FRIDAY...WHILE THE LONGWAVE TROUGH OVER THE ROCKIES CONTINUE TO DIG INTO CALIFORNIA. THE RIDGE OVER THE FORECAST AREA WILL TEND TO KEEP THE AIR MASS DRY AND STABLE. A WEAK SHORTWAVE WILL PROCEED THE RIDGE. GFS HAS A VERY WEAK SHORTWAVE MOVING THROUGH THE FORECAST AREA...WHILE ECMWF HAS A DEEP SHORTWAVE BUT WILL KEEP THE SHORTWAVE MORE TO THE NORTHEAST OF THE FORECAST AREA. GFS SOUNDING CONTINUE TO SHOW THE AIR MASS WILL BE VERY DRY. THUS WILL KEEP THE RAIN OUT. THE SOUNDING FORECAST STILL KEEPING EVERYTHING VERY DRY BELOW 850MB ...SO PLAN TO TAKE OUT THE MENTION OF RAIN FOR FRIDAY NIGHT. A WEAK SHORTWAVE WILL MIGRATE ACROSS THE FORECAST AREA ON SATURDAY AS THE SURFACE RIDGE MOVES INTO THE OHIO RIVER VALLEY. THE DEEP MOISTURE WILL BE RATHER LIMITED. THERE WILL BE A CHANCE OF RAIN ON SATURDAY...THUS WILL CALL FOR A SLIGHT CHANCE. ANOTHER SHORTWAVE WILL MOVE THROUGH THE FORECAST AREA SATURDAY NIGHT. A SURFACE LOW WILL MOVE INTO EASTERN SOUTH DAKOTA. A WARM FRONT WILL SWEEP ACROSS THE FORECAST AREA ON SATURDAY NIGHT AS A COLD FRONT MOVES THROUGH THE CENTRAL PLAINS. THE UPPER LEVEL JET WILL BE OVER EASTERN ONTARIO...AND THE LI`S ARE EXPECTED TO BE AROUND 10. DO NOT EXPECT ANY THUNDER AT THIS TIME WITH THIS SYSTEM. THERE WILL BE 0 LI`S OVER WISCONSIN AND MINNESOTA. A DEEPER SHORTWAVE WILL RELOCATE OVER THE CENTRAL U.P. SUNDAY NIGHT AND MONDAY AS THE SURFACE LOW MOVES ACROSS THE FORECAST AREA. ISENTROPIC ASCENT AND SHORTWAVE ENERGY WILL GENERATE MORE SHOWERS OVER THE FORECAST AREA. FORECAST CAPE AND LI`S SUGGEST THAT THUNDERSTORMS ARE REAL POSSIBILITY. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 320 AM EDT MON APR 16 2007 .SYNOPSIS... 07Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A TROUGH OVER THE EAST COAST...CONSISTING OF UPPER LOWS AROUND THE DELMARVA AREA AND LAKE ERIE. THESE TWO FEATURES ARE HELPING IN BRINGING AN ABNORMALLY STRONG NOR`EASTER TO THE NORTHEAST U.S...WITH A 979MB SURFACE LOW NEAR ATLANTIC CITY NEW JERSEY. TO THE WEST OF THE TROUGH...AN UPPER RIDGE EXTENDED FROM THE SOUTHERN PLAINS INTO NW ONTARIO. WITH UPPER MICHIGAN IN SUBSIDENCE BETWEEN THE UPPER RIDGE AND TROUGH...HIGH PRESSURE EXISTS AT THE SURFACE. DRY AIR ASSOCIATED WITH THE SURFACE HIGH AS EVIDENCED BY 00Z SOUNDINGS FROM INL...GRB AND CWPL HAS KEPT THE SKIES CLEAR THROUGH THE NIGHT. THUS...A FAVORABLE RADIATIONAL COOLING PATTERN HAS SET UP...AND TEMPERATURES INLAND HAVE ALREADY FALLEN INTO THE LOW 20S. FARTHER WEST...A SHRTWV TROUGH CAN BE SEEN MOVING ACROSS SASKATCHEWAN AND MONTANA...BEING PUSHED EASTWARD BY A MUCH LARGER TROUGH MOVING ACROSS THE EAST PACIFIC. DPVA AHEAD OF THE SHRTWV TROUGH...COMBINED WITH MID-LEVEL FRONTOGENESIS AND SOME UPPER DIVERGENCE IN THE RIGHT ENTRANCE REGION OF A 100KT UPPER LEVEL JET OVER NORTHERN LAKE WINNIPEG...HAS HELPED SUPPORT EXPANSIVE MID AND HIGH CLOUDS OVER THE DAKOTAS INTO MANITOBA. HOWEVER...A DRY 00Z BISMARCK SOUNDING HAS KEPT MUCH OF THE PCPN FAR TO THE NORTH...ACROSS NORTHERN MANITOBA WHERE THE 00Z CYQD SOUNDING DEPICTED MORE MOISTURE. AT THE SURFACE ASSOCIATED WITH THE SHRTWV TROUGH IS A COLD FRONT...WHICH EXTENDS FROM NE MANITOBA INTO WESTERN SOUTH DAKOTA. AHEAD OF THE FRONT... 850MB TEMPS AT 00Z WERE 13C AT BIS AND 19C AT UNR. COMPARE THIS TO BEHIND THE FRONT AT CYQD WHERE THE READING WAS 4C. HOWEVER...ALL OF THESE READINGS ARE WARMER THAN OVER THE CWA...WHICH WERE SHOWN BETWEEN -2 AND -4C PER RUC ANALYSIS. NONETHELESS...STRONG APRIL SUNSHINE ALLOWED INLAND HIGHS YESTERDAY TO REACH THE LOW 50S. && .DISCUSSION... MAIN FORECAST CONCERN IS PCPN CHANCES FOR TONIGHT AND TUESDAY. TODAY...ALTHOUGH THE NOR`EASTER IS PROGGED TO REMAIN NEARLY STATIONARY THROUGH THE DAY NEAR NEW YORK CITY...THE UPPER RIDGE AXIS OVER MINNESOTA IS EXPECTED TO BE ABLE TO PUSH INTO THE CWA BY 00Z. A FEW HIGH CLOUDS TOPPING THIS RIDGE MAY CROSS THE CWA THROUGH THE DAY...BUT OVERALL MOSTLY SUNNY SKIES ARE EXPECTED TO PREVAIL. WARMER 850MB TEMPS BETWEEN 0-2C AT 18Z ALONG WITH STRONG SUNSHINE SHOULD ALLOW BOTH INLAND LOCATIONS AND THOSE ALONG LAKE MICHIGAN (DUE TO NORTH WINDS) TO CLIMB EASILY INTO THE 50S. GIVEN THAT IT MANAGED TO GET UP TO 56 AT IRON MOUNTAIN YESTERDAY SUGGESTS THEY SHOULD BE ABLE TO MAKE 60...WHICH THE MET GUIDANCE ALSO SHOWS. LAKE BREEZES ALONG WITH A GENERAL NORTHERLY FLOW WILL KEEP LOCATIONS ALONG LAKE SUPERIOR COOLER...BUT MOST OF THEM SHOULD BE WARMER THAN YESTERDAY SINCE THE WINDS ARE PROGGED TO BE LIGHTER. TONIGHT...SHRTWV TROUGH OVER MONTANA SHOULD BE IN THE VICINITY OF GRAND FORKS AT 00Z. SOME RAIN SHOWERS MAY BE OCCURRING JUST AHEAD OF THE TROUGH ACROSS NORTHERN MINNESOTA INTO NW ONTARIO...THOUGH IMAGINE THE CLOUD BASES WILL HAVE TO BE RELATIVELY HIGH BECAUSE OF THE LOW LEVEL DRY AIR. IN ADDITION...DUE TO DEEPER DRY AIR OVER OUR CWA...THE PCPN AREA SHOULD BE FAIRLY NARROW. SINCE RIDGING WILL BE BUILDING ACROSS CENTRAL CANADA FROM THE EAST PACIFIC TROUGH MOVING INLAND...THE SHRTWV TROUGH WILL END UP DIGGING SE INTO THE WESTERN PORTION OF THE CWA BY 12Z. THEREFORE WE SHOULD SEE SOME PCPN ENTER THE WESTERN CWA JUST AFTER MIDNIGHT...AND PERHAPS REACH AS FAR EAST AS MARQUETTE COUNTY BY 12Z. THIS IS IN GOOD AGREEMENT WITH THE NAM AND GFS QPF FIELDS. AS FAR AS TYPE GOES...LATEST GFS AND NAM SOUNDINGS ARE A BIT WARMER THAN YESTERDAY...SUGGESTING RAIN AS THE MAIN TYPE. THIS SEEMS REASONABLE TOO GIVEN THE WARM AIR ASSOCIATED WITH THE RIDGE...THOUGH IT SHOULD COOL SOME DUE TO EVAPORATION. MOST LOCATIONS SHOULD SEE LOW TEMPERATURES IN THE EVENING BEFORE THE CLOUDS COME IN...EXCEPT IN THE EAST WHERE CLOUDS HOLD OFF UNTIL AFTER MIDNIGHT...ALLOWING THAT AREA TO DROP INTO THE MID 20S. TUESDAY...AS THE TROUGH OVER THE EAST PACIFIC CONTINUES TO MOVE INTO THE WEST COAST...FURTHER RIDGING WILL BE BUILT UP ACROSS THE NORTHERN PLAINS. THUS...THE SHRTWV TROUGH OVER THE WESTERN CWA WILL CONTINUE TO BE SENT SOUTHWARDS...BUT MODELS DISAGREE ON WHETHER IT TRACKS ACROSS LOWER MICHIGAN (GFS/NAM) OR THROUGH WISCONSIN (UKMET). IT SEEMS AT LEAST FROM TRENDS THAT THE FARTHER WEST TRACK MIGHT BE A BETTER SOLUTION...ESPECIALLY SINCE THERE IS A RIDGE (ALBEIT WEAKENING) BETWEEN IT AND THE NOR`EASTER. THEREFORE HAVE DECIDED TO FOLLOW THE UKMET. OVER TIME...THE MODELS CONVERGE TO THE UKMET SOLUTION. FOR THE CWA...THE IMPACT OF THIS DIFFERENCE DOES NOT APPEAR TO BE TOO IMPORTANT...SINCE THE OVERALL DYNAMICAL FORCING WEAKENS THROUGH THE DAY. THIS IS NOTED BY QPF FIELDS TOO...WHICH DIMINISH. IN FACT...THE RAIN MAY NOT MAKE IT FARTHER EAST THAN MARQUETTE COUNTY DUE TO THE DRY AIR HOLDING ON IN THE EASTERN CWA AND THE SHRTWV TROUGH DIVING SOUTH. THEREFORE...HAVE TRIMMED POPS IN THE EAST. WITH 850MB TEMPS AROUND 0C AND PLENTY OF CLOUDS AT LEAST THROUGH THE MORNING...DAYTIME HIGHS WILL END UP COOLER THAN THOSE TODAY. NONETHELESS...SOME SUN IN THE AFTERNOON SHOULD ALLOW THE INLAND AREAS TO CLIMB INTO THE LOW 50S. COOLER READINGS ARE EXPECTED ALONG LAKE SUPERIOR DUE TO STRONG HIGH PRESSURE DEVELOPING OVER NW ONTARIO...RESULTING IN A BREEZY NORTH WIND. TUESDAY NIGHT AND WEDNESDAY...PATTERN OVER THE CWA CHANGES VERY LITTLE DURING THIS PERIOD...WITH AN UPPER RIDGE STUCK/BUILDING UP INTO NW ONTARIO WHILE A SURFACE RIDGE OF HIGH PRESSURE STRENGTHENS FROM HUDSON BAY INTO MISSOURI. ENE FLOW BETWEEN THIS SURFACE RIDGE AND THE NOR`EASTER SLOWLY HEADING EAST OVER THE ATLANTIC WILL HELP BRING MOISTURE IN FROM THE NORTH ATLANTIC WESTWARD. THIS MOISTURE IS EXPECTED TO BE IN THE FORM OF AN MVFR STRATUS DECK...AT A MINIMUM...WHICH IS PROGGED TO REALLY MOVE ACROSS UPPER MICHIGAN ON WEDNESDAY. THERE ARE SOME HINTS IN THE GFS AND NAM THAT EVEN SOME QPF COULD BE PRODUCED DUE TO WEAK ISENTROPIC LIFTING. HOWEVER... GIVEN THE VERY LIGHT AMOUNTS AND TIMING ISSUES OF WHEN THE STRATUS COMES IN...HAVE DECLINED AT THE MOMENT TO PUT ANY POPS IN THE FCST. THE ENE FLOW WILL ALSO HELP IN KEEPING COOLER AIR INTO THE CWA...ESPECIALLY FOR THOSE LOCATIONS BORDERING LAKE SUPERIOR WHERE THE COLD MARINE AIR ADVECTS IN. TUE NIGHT TEMPS LOOK REASONABLE... BUT LOWERED WEDNESDAY HIGHS QUITE A BIT...ESPECIALLY WITH THE CLOUD COVER MOVING IN. WARMEST TEMPS ON WED WILL OCCUR NEAR THE WISCONSIN BORDER WHERE MID TO UPPER 40S ARE EXPECTED. WEDNESDAY NIGHT AND THURSDAY...CLOUD COVER SHOULD GRADUALLY DIMINISH...ESPECIALLY ON THURSDAY...AS THE EAST COAST TROUGH/NOR`EASTER MOVE FARTHER EAST AND ALLOW THE UPPER RIDGE TO BUILD IN. THUS...WARMER TEMPERATURES ARE EXPECTED ON THU...THOUGH A NE SURFACE WIND SHOULD STILL KEEP LOCATIONS ALONG LAKE SUPERIOR IN THE LOW 40S. CLOUDS DURING THE NIGHT WEDNESDAY NIGHT WILL HELP KEEP MINS UP AS SHOWN IN THE PREVIOUS FORECAST. BEYOND THURSDAY...THE TROUGH MOVING INTO THE WEST COAST ON TUE MAY IMPACT THE CWA LATE FRIDAY AS INDICATED IN THE 00Z ECMWF/GFS/CANADIAN...THUS CHANCE/SLIGHT CHANCE POPS STILL SEEM OKAY FOR FRIDAY NIGHT. RIDGING SHOULD BUILD BACK INTO THE CWA BEHIND THIS FEATURE ON SATURDAY AS ANOTHER TROUGH DIGS INTO THE SOUTHWEST U.S.. WARM ADVECTION DUE TO THE BUILDING RIDGING MAY RESULT IN A FEW SHOWERS FOR SAT/SAT NIGHT. HOWEVER...THINK THE BETTER CHANCE FOR PCPN IS LATE SUN OR SUN NIGHT WHEN THE SOUTHWEST U.S. TROUGH LIFTS OUT ACROSS THE PLAINS...RESULTING IN A FAIRLY DEEP SYSTEM WHICH IS PROGGED TO HEAD UP TOWARDS THE GREAT LAKES. IF THE 00Z ECMWF IS CORRECT...SOME PLACES IN THE WEST HALF OF THE CWA COULD TOUCH 70F AS 850MB TEMPS CLIMB TO 12C AT 00Z MON. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 348 PM EDT SUN APR 15 2007 .DISCUSSION... THE MAIN CONCERNS WITH THIS FORECAST PACKAGE ARE THE OVERNIGHT TEMPERATURES. WATER VAPOR IMAGERY AND RUC SHOWING A CLOSED LOW OVER LAKE HURON...WITH A DEEP TROUGH DRAPED INTO THE EASTERN TENNESSEE RIVER VALLEY. A RIDGE EXTENDS FROM THE SOUTHERN PLAINS NORTH THROUGH THE DAKOTAS AND INTO WESTERN ONTARIO. A CLOSED LOW IS ALSO OVER SOUTHERN CALIFORNIA. WEAK SHORTWAVES ROTATING THROUGH THE BASE OF THE LAKE HURON LOW ARE OVER THE EASTERN U.P. THIS PRODUCED A FEW CLOUDS OVER THE AREA THIS MORNING. A SURFACE RIDGE DOMINATES THE THE UPPER GREAT LAKES. TO THE WEST A LOW IS OVER SOUTHERN MANITOBA. A COLD FRONT LINKS THIS LOW WITH ANOTHER OVER CENTRAL HIGH PLAINS OF WYOMING AND COLORADO. THE LOW OVER LAKE HURON WILL MERGE WITH ANOTHER LOW OVER EASTERN OHIO RIVER VALLEY AND END UP OVER PENNSYLVANIA TONIGHT AND MONDAY. THE RIDGE WILL FORM AN OMEGA BLOCK OVER THE CENTRAL PLAINS WHICH WILL REMAIN NEARLY STATIONARY. THE SURFACE RIDGE WILL REMAIN OVER THE FORECAST AREA AS WELL. A LOW WILL MOVE INTO NORTHWEST HUDSON BAY. A COLD FRONT WILL EXTEND TO THE SOUTHWEST THROUGH EASTERN DAKOTAS INTO NEBRASKA. THE DRY AIR AND STABLE CONDITIONS SHOULD KEEP SKIES MOSTLY CLEAR OVERNIGHT. WINDS WILL BE LIGHT TONIGHT ALLOWING PLENTY OF RADIATIONAL COOLING WHICH WOULD MAKE FORECASTING THE TEMPERATURES DIFFICULT. GUIDANCE CALLING FOR TEMPERATURES IN THE LOW TO MID 20S SIMILAR TO LAST NIGHT. TRAJECTORY FORECAST DRAWING THE AIR MASS FROM CENTRAL ONTARIO INTO THE AREA TONIGHT...HOWEVER... SURFACE HEATING TODAY WILL DELAY RADIATIONAL COOLING. THEREFORE... PLAN TO STAY FAIRLY CLOSE TO GUIDANCE. THE DRY STABLE AIR WILL CONTINUE THROUGH MONDAY BRINGING PLENTY OF SUN WHICH WILL MAKE A DAY SIMILAR TODAY SO WILL KEEP THE TEMPERATURES ABOUT THE SAME OR A LITTLE HIGHER. A SHORTWAVE WILL MOVE THROUGH THE MID LEVEL RIDGE MONDAY NIGHT. THE COLD FRONT WILL LIKEWISE SWEEP THROUGH THE AREA. A RIDGE WILL PUSH INTO EASTERN MANITOBA AND WESTERN ONTARIO. THE FORECAST SOUNDINGS INDICATE A NARROW BAND OF MOISTURE ACCOMPANYING THE FRONTAL SYSTEM. ISENTROPIC ASCENT WITH THE FRONT AND INSTABILITY WITH THE Q-VECTOR CONVERGENCE WILL GENERATE SOME PRECIPITATION ACROSS THE AREA. GFS/NAM SOUNDINGS SUGGEST THAT THE TEMPERATURES WILL BE AROUND 6C AT 900MB OVER THE SOUTHERN U.P. AND AROUND 0C OVER THE NORTH. THEREFORE...EXPECTING TO SEE A MIX OF RAIN AND SNOW OVER THE NORTH AND MAINLY RAIN OVER THE SOUTH WITH THIS SYSTEM. THE FRONT WILL MOVE EAST OF THE AREA ON TUESDAY ALONG WITH THE SHORTWAVE ENERGY. THE MID LEVEL RIDGE WILL ALSO SHIFT INTO WESTERN ONTARIO. THE AIR MASS WILL BE DRY ABOVE 850MB. SOUNDING DATA SHOW THE SURFACE DEW POINTS MAY BE DRY ENOUGH TO LIMIT THE AMOUNT OF PRECIPITATION THAT WILL REACH THE GROUND. THUS WILL KEEP A SLIGHT CHANCE OF RAIN THROUGH THE DAY. THE RIDGE OVER MINNESOTA AND WESTERN ONTARIO WILL NAVIGATE OVER THE GREAT LAKES TUESDAY NIGHT. DRY STABLE AIR ACCOMPANYING THIS RIDGE SHOULD END THE PRECIPITATION OVER THE AREA. THE RIDGE WILL REMAIN IN PLACE OVER THE AREA THROUGH WEDNESDAY. ...EXTENDED... 00Z THU THROUGH SUNDAY THE ECMWF AND GFS ARE IN A FAIR AGREEMENT THROUGH THE EXTENDED. WHERE THERE IS MINOR DIFFERENCES...THE NCEP ENSEMBLE FAVORS MORE WITH THE GFS OVER THE CENTRAL NORTH AMERICA AND WITH THE ECMWF OVER THE ROCKIES AND THE WEST COAST. BY DAY 6 IT APPEARS THAT THE ENSEMBLE FAVOR MORE OF COMPROMISE SOLUTION OF ECMWF AND GFS. CONSIDERING THE TRACK RECORD OF THE ECMWF AND GFS OVER THE LAST FEW DAYS...PLAN TO FOLLOW THE ENSEMBLE SOLUTION. THE MID LEVEL LOW WILL SHIFT FROM THE OHIO RIVER VALLEY TO OFF THE COAST OF SOUTH CAROLINA WEDNESDAY NIGHT INTO THURSDAY. THE MID LEVEL RIDGE WILL EXTEND FROM THE UPPER MISSISSIPPI RIVER VALLEY TO A HIGH OVER SOUTHERN HUDSON BAY. A CLOSED LOW WILL PUSH INTO WESTERN NORTH DAKOTAS. WEAK SHORTWAVES TRACKING THROUGH THE RIDGE WILL PASS THROUGH THE FORECAST AREA. MEANWHILE...THE SURFACE RIDGE BLANKETS THE UPPER GREAT LAKES AND THE MISSISSIPPI RIVER VALLEY. MODELS CONTINUE TO SHOW A FAIRLY DRY AIR MASS...THUS DO NOT EXPECT MUCH IF ANY PRECIPITATION. THE RIDGE WILL EDGE INTO EASTERN ONTARIO THURSDAY NIGHT AND FRIDAY. THE NORTH DAKOTA LOW WILL LIFT INTO SOUTHWEST MANITOBA. THE ACCOMPANYING SHORTWAVE WILL RUN UP AGAINST THE OMEGA BLOCK OVER THE GREAT LAKES AND STALL OUT. MODELS SHOWING DEEP MOISTURE WILL SLIDE TO THE SOUTH OF THE FORECAST AREA. THEREFORE...EXPECT THE DRY CONDITIONS TO PERSIST THROUGH FRIDAY. THE OMEGA BLOCK WILL WEAKEN AS IT BLANKETS THE GREAT LAKES FRIDAY NIGHT AND SATURDAY. THIS WILL ALLOW THE SURFACE LOW AND COLD FRONT TO MOVE THROUGH THE CENTRAL PLAINS REACHING THE EASTERN DAKOTAS BY SUNDAY MORNING AND PROGRESSING NORTHEAST INTO MINNESOTA NEXT SUNDAY. WARM MOIST GULF AIR WILL BE DRAWN INTO THE AREA AHEAD OF THE FRONTAL SYSTEM AND SHOULD SUPPORT GENERATING SOME RAIN OVER THE FORECAST AREA. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 335 AM EDT SUN APR 15 2007 .SYNOPSIS... 07Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A HIGHLY AMPLIFIED...BUT SOMEWHAT PROGRESSIVE PATTERN ACROSS NORTH AMERICA. A TROUGH STRETCHED FROM THE WESTERN GREAT LAKES INTO THE LOWER MISSISSIPPI VALLEY...A RIDGE WAS LOCATED ON THE WEST SIDE OF THE PLAINS INTO SOUTH CENTRAL CANADA...AND A TROUGH BEGINNING TO SPLIT UP WAS LOCATED ALONG THE WEST COAST. WITHIN THE EASTERN TROUGH...THE MAIN FEATURES OF INTEREST ARE AN UPPER LOW CENTER NEAR TIMMINS ONTARIO AND A STRONG SHRTWV AT THE BASE OF THE TROUGH IN MISSISSIPPI. 500MB TEMPS WERE RELATIVELY CHILLY ON THE WEST SIDE OF THE UPPER LOW OVER UPPER MICHIGAN...WITH THE 00Z RUC ANALYSIS SHOWING READINGS OF -30C. DAYTIME HEATING YESTERDAY ALONG WITH SOME SURFACE MOISTURE AND THESE COOL READINGS HELPED DEVELOP A FEW SHOWERS DURING THE AFTERNOON AND EVENING. HOWEVER...SINCE THESE WERE INSTABILITY BASED...THEY HAVE COMPLETELY DIMINISHED. IN FACT... UNIDIRECTIONAL NORTHERLY FLOW ON THE BACK SIDE OF THE UPPER LOW IS ALSO HELPING TO DRIVE DRIER AIR INTO AT THE LEAST THE WESTERN 2/3 OF THE CWA...BASED ON CURRENT IR SATELLITE IMAGERY AND THE 00Z CWPL SOUNDING (PRECIPITABLE WATER ON THE SOUNDING WAS 0.20 INCHES AND IT WAS ALSO INVERTED-V UP TO 700MB). AT THE SURFACE...1016MB HIGH PRESSURE EXTENDED FROM NORTHERN ONTARIO INTO THE CENTRAL PLAINS... SANDWICHED IN BETWEEN 995MB LOW PRESSURE NEAR ASHEVILLE NORTH CAROLINA AND A 1003MB LOW PRESSURE TROUGH STRETCHING FROM SASKATCHEWAN INTO MONTANA. LIGHT WINDS ASSOCIATED WITH A RELATIVELY WEAK GRADIENT OVER THE CWA...PARTLY CLOUDY SKIES AND DRY AIR HAS HELPED SOME INLAND LOCATIONS DROP INTO THE LOW 20S. && .DISCUSSION... MAIN FORECAST CONCERNS ARE TEMPERATURES THE NEXT FEW DAYS AND PCPN CHANCES FOR MONDAY NIGHT AND TUESDAY. TODAY...AS THE STRONG SHRTWV OVER MISSISSIPPI LIFTS UP ALONG THE MID-ATLANTIC COAST...CAUSING THE SURFACE LOW NEAR ASHEVILLE TO GO INTO BOMBOGENESIS AND DEEPEN TO AROUND 983MB BY 00Z NEAR ATLANTIC CITY NJ...THE UPPER LOW NEAR TIMMINS WILL BE PULLED SOUTHWARD. BY 00Z...THE MODELS PROG THE UPPER LOW OVER THE NORTH CHANNEL. SOME MID CLOUDS OVER NE ONTARIO ASSOCIATED WITH THIS LOW MAY IMPACT THE EASTERN CWA. OTHERWISE...THE REST OF THE CWA SHOULD BE UNDER THE INFLUENCE OF SUBSIDENCE DOWNSTREAM OF THE PLAINS RIDGE MOVING EASTWARD. UNIDIRECTIONAL NORTHERLY FLOW IN THE TROPOSPHERE SHOULD CONTINUE TO DRIVE DRIER AND DRIER AIR SOUTHWARD FROM NW ONTARIO... AND WITH THE UPPER LEVEL SUBSIDENCE...SKIES SHOULD CLEAR OVER THE REST OF THE CWA THIS MORNING. THE NORTHERLY FLOW WILL ALSO HELP IN KEEPING COOL READINGS ALONG THE LAKESHORE. INLAND...STRONG MIXING UP TO AT LEAST 800MB SHOULD OCCUR...AND WITH 850MB TEMPS AROUND -4C...HIGHS WILL CLIMB INTO THE LOW 50S WITH DEWPOINTS FALLING INTO THE MID TEENS. TONIGHT...UPPER LOW OVER THE NORTH CHANNEL IS PROGGED TO BEGIN ITS PHASING WITH THE STRENGTHENING NOR`EASTER...WHICH DEEPENS TO 974MB NEAR NEW YORK CITY AT 12Z MON. WHILE PLENTY OF WATER...WIND AND WEATHER CONCERNS ARE EXPECTED OVER THE NORTHEAST U.S. WITH THIS SYSTEM...THE CWA WILL BE UNDER THE INFLUENCE OF DRY AIR AND SUBSIDENCE ASSOCIATED WITH THE UPPER RIDGE TRYING TO BUILD INTO THE CWA. AT 12Z MON...THE UPPER RIDGE AXIS SHOULD BE APPROACHING THE DULUTH AREA. MEANWHILE AT THE SURFACE...A RIDGE OF HIGH PRESSURE WILL REMAIN. DIMINISHING WINDS IN THE EVENING...CLEAR SKIES AND DRY AIR SHOULD SETUP A GOOD RADIATIONAL COOLING NIGHT...ESPECIALLY OVER SNOWPACK AREAS. THE COOLEST INLAND AREAS MAY DROP AS FAR AS THE MID TEENS...ESPECIALLY SINCE PRECIPITABLE WATER IS PROGGED AROUND 0.20 OF AN INCH. MONDAY...THE SPLITTING UP WEST COAST TROUGH...IN PARTICULAR THE NORTHERN PORTION SHRTWV WHICH HAS BEEN MOVING EASTWARD UP TO THIS TIME...WILL FINALLY BE ABLE TO PUSH THE UPPER RIDGE AXIS INTO THE CWA BY 00Z. THE SHRTWV IS PROGGED TO REACH NW MN BY 00Z. SUBSIDENCE FROM THE UPPER RIDGING ALOFT ALONG WITH DRY AIR IN PLACE ASSOCIATED WITH THE SURFACE HIGH PRESSURE RIDGE SHOULD KEEP THE AREA PCPN FREE. SKIES SHOULD ALSO REMAIN MAINLY CLEAR...WITH PERHAPS A FEW HIGH CLOUDS MOVING ACROSS WITH THE UPPER RIDGE. PLENTY OF SUNSHINE ALONG WITH DRY AIRMASS SHOULD ALLOW FOR DEEP MIXING AGAIN...AT LEAST TO 825MB FOR INLAND AREAS. WITH 850MB TEMPS PROGGED AROUND 0C AT 18Z...INLAND AREAS SHOULD CLIMB TO NEAR 60. LOCATIONS ALONG LAKE SUPERIOR WILL EXPERIENCE COOLER READINGS DUE TO BOTH LAKE BREEZES AND STILL A GENERAL NORTHERLY FLOW. ONLY LAKE BREEZE ALONG LAKE MICHIGAN APPEARS TO OCCUR IN MENOMINEE COUNTY...THUS MUCH OF THE LAKE MICHIGAN AREA SHOULD ALSO BE WARMER DUE TO DOWNSLOPING OF THE NORTH WIND. MONDAY NIGHT AND TUESDAY...THE SOUTHERN PORTION OF THE SHRTWV OVER NW MN IS PROGGED TO DROP SE ACROSS THE CWA DURING THIS PERIOD...WITH SLIGHT DIFFERENCES IN SPEED BETWEEN THE NAM/GFS AND UKMET. GIVEN THE SLOW NATURE OF THE UPPER RIDGE TO PUSH EASTWARD DUE TO THE STRONG NOR`EASTER AHEAD OF IT...FEEL THE SLOWER SOLUTION OF THE GFS MIGHT BE BETTER TO FOLLOW. TRENDS IN THE NAM WITH THIS SHRTWV ARE ALSO SLOWER. THEREFORE...HAVE ADJUSTED POPS WITH THE DPVA FROM THE SHRTWV ACCORDINGLY...KEEPING AT LEAST THE EASTERN CWA DRY MONDAY NIGHT. THE DRY AIR IN PLACE BEFORE THE SHRTWV ARRIVAL ALSO SUPPORTS A DRIER FORECAST. REGARDING PCPN TYPE...EVAPORATIVE COOLING FROM THE PCPN MAY ALLOW RAIN TO CHANGE OVER TO SNOW...AT LEAST ACROSS THE NORTHERN U.P. WHERE PROFILES FROM THE NAM/GFS/UKMET ARE COOLER. ALTHOUGH LOW TEMPERATURES IN THE FORECAST ARE DEPICTED BELOW FREEZING...THERE SHOULD NOT BE ANY FREEZING RAIN ISSUE SINCE THESE LOW TEMPS WILL OCCUR DURING THE RADIATIONAL COOLING PRIOR TO THE THICKER CLOUD ARRIVAL. ONCE THE THICKER CLOUDS ARRIVE...TEMPERATURES SHOULD CLIMB BACK UP TO AT OR AROUND 32. DAYTIME HEATING SHOULD ALSO CHANGE ANY SNOW OVER TO RAIN TUESDAY AFTERNOON AS THE SHRTWV CONTINUES TO CROSS...HOWEVER THERE MAY NOT BE MUCH PCPN LEFT IF THE GFS IS CORRECT. THEREFORE...HAVE MAINTAINED THE SLIGHT CHANCE POPS FOR TUESDAY AFTERNOON...EXCEPT IN THE FAR WEST WHERE DYNAMICAL FORCING IS LOST. CLOUD COVER TUESDAY ALONG WITH COOLER 850MB TEMPS AND HIGH PRESSURE BUILDING IN FROM CANADA RESULTING IN NORTHERLY LOW LEVEL FLOW WILL RESULT IN COOLER HIGH TEMPERATURES THAN MONDAY...ON THE ORDER OF 5-10 DEGREES. TUESDAY NIGHT AND BEYOND...ANOTHER TROUGH PROGGED TO DIVE INTO THE WEST COAST WILL RESULT IN THE DEVELOPMENT OF ANOTHER RIDGE IN THE PLAINS TUESDAY EVENING. HOWEVER...THIS RIDGE MAY TAKE A COUPLE DAYS TO PUSH EASTWARD DUE TO PERSISTENT TROUGHING OVER THE EAST COAST (COMBINATION OF TUESDAYS SHRTWV AND THE NOR`EASTER SLOWLY HEADING EAST). SOME LOW CLOUDS MAY TRY TO WRAP THEMSELVES BACK WESTWARD INTO THE CWA ON WEDNESDAY...BUT WITH A STRONG HIGH OVER NORTHERN ONTARIO PUSHING DRY AIR IN ON NE WINDS...THEY SHOULDNT GET TOO FAR WEST. ON FRIDAY...THERE ARE INDICATIONS OF THE SHRTWV AT THE BASE OF THE NEW WEST COAST TROUGH LIFTING UP INTO NORTHERN MN WHILE ANOTHER SHRTWV TROUGH DROPS INTO CALIFORNIA. LATER FORECASTS MAY NEED A CHANCE OF RAIN WITH THIS FEATURE...BUT WITH THE UKMET STILL SHOWING THE UPPER RIDGE FIRMLY INTACT OVER THE CWA...WILL NOT INCLUDE ANY PCPN CHANCES IN THIS FORECAST. INDICATIONS ARE ALSO APPARENT WITH THIS MODEL SUITE AND EVEN THOSE YESTERDAY THAT THE OMEGA BLOCK WHICH FORMS MID-WEEK WILL NOT BE STAGNANT. IN FACT...IT LOOKS LIKE THE WEATHER MAY TRY TO GET MORE ACTIVE NEXT WEEKEND AS THE NEXT CALIFORNIA SHRTWV TROUGH LIFTS OUT INTO THE PLAINS... BRINGING GULF OF MEXICO MOISTURE NORTHWARD. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BINGHAMTON NY 205 PM EDT MON APR 16 2007 .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THE START OF THE EXTENDED PERIOD /WED NIGHT-THU/ WILL STILL FEATURE LEFT OVER MOISTURE ROTATING AROUND THE MASSIVE CUTOFF OVER THE WESTERN ATLANTIC. STILL LOOKS COLD ENOUGH AT NIGHT FOR SOME SHSN...BUT TEMPS IN THE 40S DURING THE DAY SHOULD ENSURE ONLY RAIN DURING THE DAY. HEADING INTO FRIDAY AND THE WEEKEND THE PATTERN OVER NORTH AMERICA EVOLVES INTO AN IMPRESSIVE OMEGA BLOCK. THIS TROUGH-RIDGE-TROUGH PATTERN SLOWLY SHIFTS EAST AS WE HEAD INTO THE WEEKEND. THIS WILL BRING BUILDING HEIGHTS AND MODERATING TEMPERATURES TO THE AREA WITH LITTLE OR NO PRECIPITATION THROUGH SUNDAY. THIS WILL BE A VERY GOOD THING IN TERMS OF HYDRO AS IT APPEARS THE MODERATING TREND WILL BE SLOW ENOUGH TO ENSURE A SLOW RELEASE OF THE NEW SNOWPACK INTO AREA RIVERS AND STREAMS. WILL CERTAINLY HAVE TO KEEP AN EYE ON THIS WITH RIVER LEVELS QUITE HIGH EVEN BEFORE THIS EVENT. THE RIDGING THAT MOVES OVER US THIS WEEKEND WILL BEGIN TO BREAK DOWN HEADING INTO EARLY NEXT WEEK...BRINGING A RENEWED CHANCE FOR SHOWERS BY MONDAY...BUT THIS TIME THEY WILL CERTAINLY BE IN THE FORM OF RAIN. && .AVIATION /161800Z-171800Z/... WIDELY VARIABLE CONDITIONS ATTM WITH STRONG SNOW BAND SET UP JUST WEST OF KSYR EXTENDING SOUTH THROUGH KELM AND KITH AND THEN CURLING SOUTHEAST TO KAVP. WITHIN THE BAND...VLIFR AND LIFR CONDITIONS DUE TO LOW VSBYS IN MODERATE TO HEAVY SNOW WITH IFR CIGS. KBGM AND KSYR ARE ON THE EDGE OF THE BAND WITH SOME IMPROVEMENT TOWARDS HIGH IFR/ LOW MVFR CONDITIONS. KRME...WHERE PCP HAS GENERALLY ENDED ATTM IS VFR WITH SOME PATCHY LIGHT RAIN. EXPECT CURRENT CONDITIONS TO CONTINUE OVER THE NEXT FOUR HOURS WITH POSSIBLE DETERIORATION AT KBGM/KRME WITH NEW ECHOES NOW OVER DELEWARE/OTSEGO COUNTIES MOVING WEST. AS WE HEAD TOWARDS THIS EVENING...WE EXPECT A GRADUAL WEAKENING OF PRECIPITATION OVER THE AREA...WHICH SHOULD ALLOW SLOW IMPROVEMENT TOWARDS MVFR WITH INTERMITTENT IFR PERIODS INSIDE REMAINING SNOW SHOWERS. AFTER MIDNIGHT ALL SITES SHOULD IMPROVE TO MVFR WITH A FEW REMAINING SNOW SHOWERS. DURING THE MORNING ON TUESDAY...EXPECT SOME OCCASIONAL RAIN SHOWERS ACROSS THE TERMINALS...WITH POSSIBLE SNOW AT KBGM. SHOWERS WILL BE MORE PREVALENT AS THE MORNING PROGRESSES. MFVR CONDITIONS SHOULD HOLD THROUGH 18Z EXCEPT AT KAVP WHERE LOW VFR CIGS SHOULD HOLD OUTSIDE OF ANY SHOWERS. && .PREV DISCUSSION... /ISSUED 1157 AM EDT MON APR 16 2007/ SHORT TERM /REST OF TODAY/... DEFORMATION ZONE SNOWS ON NW PERIPHERY OF COASTAL BOMB WILL CONTINUE TO BE FED BY ATLANTIC MOISTURE WRAPPING INTO THE SYSTEM THROUGH THE AFTERNOON...ALTHOUGH SOME FILLING/WEAKENING NOTED AND EXPECTED TO OCCUR. A COUPLE WRINKLES WILL KEEP ADDITIONAL ACCUMULATIONS TO A MINIMUM FOR THE REST OF THE DAY. BESIDES SFC TEMPS WARMING A FEW MORE DEGREES TO THE MID 30S...DEEPER WARM 850-925 MB AIR WILL ALSO KEEP WRAPPING BACK INTO CNY/NEPA WITH SOME COLD AIR UNDERCUTTING BACK INTO THE POCONOS. HAVE ALREADY SEEN MIX WITH RAIN IN THE UPPER MOHAWK VALLEY AND NRN SUSQUEHANNA REGION NW CATSKILLS MOVING WESTWARD...WITH AN ALL RAIN EVENT FOR SW CATSKILLS (SULLIVAN CO) THUS FAR. ALSO...MILDER COLUMN WILL FORCE DENDRITIC ZONE HIGHER INTO THE ATMOSPHERE THIS AFTERNOON FOR MORE INEFFICIENT SNOWFLAKE PRODUCTION. THAT COUPLED WITH SOME FIZZLING OF DEF ZONE FORCING THROUGH THE DAY WILL HELP TO GIVE US ONLY ANOTHER 1-4 ELEVATION DEPENDENT INCHES...AND MAINLY SLUSH ON ROADS. WINTER WARNINGS/ADVISORIES WILL BE CONTINUED AS WE HAVE ALREADY HAD SIGNIFICANT ACCUMS RANGING VASTLY FROM 5-7 INCHES VALLEYS TO 14-15 INCHES HIGHER TERRAIN AROUND A GOOD CHUNK OF CNY INTO NRN TIER PA. LEANING TOWARD THE LOWER END OF THAT RANGE TOWARD THE WB-SCRANTON METRO AREA...EXCEPT ISOLD SPOTS IN NRN POCONOS MAY HAVE NEAR 10 INCHES WAY UP HIGH. SULLIVAN COUNTY NY SLAMMED WITH FLOODING RAINS. POWER OUTAGES GALORE DUE TO HEAVY SNOW LADEN TREES...AND REPORTS FROM LOCAL OFFICIALS OF MANY PROBLEMS IN MANY COUNTIES. ONLY SIG CHANGE TO ANYTHING WAS TO DROP FLOOD WATCH FOR DELAWARE- SULLIVAN- PIKE. FLOOD WARNINGS IN PLACE HANDLING THAT SITUATION FINE...SO SIMPLIFIED THINGS. PREV DISCUSSION... /ISSUED 725 AM EDT MON APR 16 2007/ AVIATION /161200Z-171200Z/... DEEP CYCLONE CONTINUES TO PRODUCE SNOW OVER ALL TERMINALS THIS MORNING. LIFR/IFR VSBYS PREDOMINANT FOR NEXT FEW HRS IN MOST INTENSE SNOW BANDS. CIGS/VSBYS GRADUALLY RISE TO MVFR DRNG THE AFTERNOON WITH A LITTLE MORE MIXING OCCURRING. HOWEVER INTENSE MESOSCALE SNOW BAND CUD LEAD TO BRIEF PERIODS OF LIFR CONDS THRU 18Z...ESPECIALLY IN KSYR/KBGM/KITH AND KELM. SNOW SHOWERS BECOME SCTD ACROSS MOST TERMINALS AFTER 00Z. NORTHWEST WINDS BTWN 10-20KTS WITH GUSTS OF 25-35KTS EXPECTED THRU 01Z BEFORE SLOWLY DIMINISHING. PREV DISCUSSION... /ISSUED 453 AM EDT MON APR 16 2007/ SHORT TERM /TODAY THROUGH TUESDAY/... NOREASTER CONTINUES TO BLANKET UPSTATE NY AND NEPA WITH SNOW/HEAVY RAIN. 971MB SFC LOW IS SITTING NEAR THE NY BIGHT THIS MORNING AND FLINGING SIGNIFICANT WRAP-AROUND BACK INTO THE FA. SNOWFALL REPORTS ON AVG RUNNING ARND SIX INCHES AT THE HIGHER ELEVATIONS TO BTWN 2-3 IN THE VALLEYS. NOTHING SIGNIFICANT BY ANY STRETCH OF THE IMAGINATION BUT THINK LATEST FCST SNOWFALL TOTALS ARE WITHIN REACH. INTENSE BAND IS LOCATED ALONG I-81 CORRIDOR PRESENTLY WITH 1/2-3/4SM VISIBILITIES IN THIS BAND. HAVE AVGD AN INCH PER HOUR FOR THE PAST 6 HRS HERE AT THE OFFICE AND EXPECT THIS TO CONTINUE UNTIL APPROX 12Z. THE BIG MONKEY WRENCH IN THIS FCST IS THE DRY SLOT WRAPPING INTO NEPA. THIS IS SLOWLY WORKING ITS WAY WEST...A LITTLE FURTHER THAN ORIGINALLY THOUGHT. HOWEVER...NAM CONSISTENTLY SHOWED QPF SLACKING OFF ACROSS THE AREA THIS MORNING. WHILE THERE WAS SOME CONCERN THIS WUD BRING PCPN TO AN END QUICKER THAN FIRST THOUGHT EAST OF THE I-81 CORRIDOR...LATEST RADAR IMAGES SHOW PCPN CONTINUALLY DEVELOPING. THUS...HAVE KEPT HEAVY SNOW IN FOR GOOD PART OF THE DAY FOR ALONG AND WEST OF I-81. SNOWFALL TOTALS LOOKS TO RANGE ANYWHERE FROM 4-12 INCHES...LOWEST IN THE VALLEYS AND HIGHEST ON THE HILLTOPS. OTHER MAJOR CONCERN IS FLOODING IN THE WRN CATSKILLS TODAY. TWO TO THREE INCHES OF RAIN FELL IN THESE AREAS OVER THE PAST 24 HRS. CUD SEE ADDNL AMOUNTS OF NR AN INCH THROUGH NOON TODAY...LEADING TO CONTINUED THREAT FOR FLOODING. ALREADY HAVE NUMEROUS REPORTS OF ROADS CLOSED IN DELAWARE AND SULLIVAN COUNTIES. THUS WITH THE LATEST MODEL GUIDANCE AND CURRENT TRENDS...HAVE DROPPED WINTER WX ADVISORY FOR PIKE AND SULLIVAN WITH ONLY A COUPLE OF INCHES EXPECTED OVER THE FAR WEST. DELAWARE WAS A TRICKIER CALL WITH RAIN IN THE EAST AND SNOW IN THE WEST. OPTED TO LEAVE THE WINTER STORM WARNING GOING BUT PROBABLY ONLY LOOKING AT 5-8 INCH (MINIMAL WARNING) AMOUNTS. HAVE ALSO CUT DOWN ON SNOWFALL ACCUMS OVER EASTERN ONEIDA AS NAM/RUC BRING 850/800MB TEMPS > 0C INTO THIS AREA THIS MORNING. THIS WILL LIKELY LEAD TO A SNOW/RAIN/SLEET MIX FOR A TIME AND REDUCE AMOUNTS TO CLOSER TO A 4-8 INCH RANGE OVER THE FAR EAST. ALL IN ALL...TAPERED DOWN AMOUNTS MOST AREAS FOR STORM TOTALS. HIGHEST AMOUNTS STILL EXPECTED ALONG THE I-81 CORRIDOR WITH THE MOST INTENSE RATES THRU 12Z. ACCUM PAST THAT POINT MAY BE HARD TO COME BY UNLESS SNOW CAN FALL AT AN EXTREMELY INTENSE RATE. HOWEVER...SNOW WILL BE FALLING ON EXISTING SNOW COVER SO MAY BE EASIER TO ACCUMULATE THAN IF IT WERE FALLING ON BARE GROUND. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ009- 015>018-022>025-036-037-044>046-055>057. PA...WINTER STORM WARNING UNTIL 8 PM EDT THIS EVENING FOR PAZ038- 039-043. WINTER WEATHER ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ040- 044-047-072. && $$ LONG TERM...JMA AVIATION...JMA ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1157 AM EDT MON APR 16 2007 .SHORT TERM /REST OF TODAY/... DEFORMATION ZONE SNOWS ON NW PERIPHERY OF COASTAL BOMB WILL CONTINUE TO BE FED BY ATLANTIC MOISTURE WRAPPING INTO THE SYSTEM THROUGH THE AFTERNOON...ALTHOUGH SOME FILLING/WEAKENING NOTED AND EXPECTED TO OCCUR. A COUPLE WRINKLES WILL KEEP ADDITIONAL ACCUMULATIONS TO A MINIMUM FOR THE REST OF THE DAY. BESIDES SFC TEMPS WARMING A FEW MORE DEGREES TO THE MID 30S...DEEPER WARM 850-925 MB AIR WILL ALSO KEEP WRAPPING BACK INTO CNY/NEPA WITH SOME COLD AIR UNDERCUTTING BACK INTO THE POCONOS. HAVE ALREADY SEEN MIX WITH RAIN IN THE UPPER MOHAWK VALLEY AND NRN SUSQUEHANNA REGION NW CATSKILLS MOVING WESTWARD...WITH AN ALL RAIN EVENT FOR SW CATSKILLS (SULLIVAN CO) THUS FAR. ALSO...MILDER COLUMN WILL FORCE DENDRITIC ZONE HIGHER INTO THE ATMOSPHERE THIS AFTERNOON FOR MORE INEFFICIENT SNOWFLAKE PRODUCTION. THAT COUPLED WITH SOME FIZZLING OF DEF ZONE FORCING THROUGH THE DAY WILL HELP TO GIVE US ONLY ANOTHER 1-4 ELEVATION DEPENDENT INCHES...AND MAINLY SLUSH ON ROADS. WINTER WARNINGS/ADVISORIES WILL BE CONTINUED AS WE HAVE ALREADY HAD SIGNIFICANT ACCUMS RANGING VASTLY FROM 5-7 INCHES VALLEYS TO 14-15 INCHES HIGHER TERRAIN AROUND A GOOD CHUNK OF CNY INTO NRN TIER PA. LEANING TOWARD THE LOWER END OF THAT RANGE TOWARD THE WB-SCRANTON METRO AREA...EXCEPT ISOLD SPOTS IN NRN POCONOS MAY HAVE NEAR 10 INCHES WAY UP HIGH. SULLIVAN COUNTY NY SLAMMED WITH FLOODING RAINS. POWER OUTAGES GALORE DUE TO HEAVY SNOW LADEN TREES...AND REPORTS FROM LOCAL OFFICIALS OF MANY PROBLEMS IN MANY COUNTIES. ONLY SIG CHANGE TO ANYTHING WAS TO DROP FLOOD WATCH FOR DELAWARE- SULLIVAN- PIKE. FLOOD WARNINGS IN PLACE HANDLING THAT SITUATION FINE...SO SIMPLIFIED THINGS. && .PREV DISCUSSION... /ISSUED 725 AM EDT MON APR 16 2007/ AVIATION /161200Z-171200Z/... DEEP CYCLONE CONTINUES TO PRODUCE SNOW OVER ALL TERMINALS THIS MORNING. LIFR/IFR VSBYS PREDOMINANT FOR NEXT FEW HRS IN MOST INTENSE SNOW BANDS. CIGS/VSBYS GRADUALLY RISE TO MVFR DRNG THE AFTERNOON WITH A LITTLE MORE MIXING OCCURRING. HOWEVER INTENSE MESOSCALE SNOW BAND CUD LEAD TO BRIEF PERIODS OF LIFR CONDS THRU 18Z...ESPECIALLY IN KSYR/KBGM/KITH AND KELM. SNOW SHOWERS BECOME SCTD ACROSS MOST TERMINALS AFTER 00Z. NORTHWEST WINDS BTWN 10-20KTS WITH GUSTS OF 25-35KTS EXPECTED THRU 01Z BEFORE SLOWLY DIMINISHING. PREV DISCUSSION... /ISSUED 453 AM EDT MON APR 16 2007/ SHORT TERM /TODAY THROUGH TUESDAY/... NOREASTER CONTINUES TO BLANKET UPSTATE NY AND NEPA WITH SNOW/HEAVY RAIN. 971MB SFC LOW IS SITTING NEAR THE NY BIGHT THIS MORNING AND FLINGING SIGNIFICANT WRAP-AROUND BACK INTO THE FA. SNOWFALL REPORTS ON AVG RUNNING ARND SIX INCHES AT THE HIGHER ELEVATIONS TO BTWN 2-3 IN THE VALLEYS. NOTHING SIGNIFICANT BY ANY STRETCH OF THE IMAGINATION BUT THINK LATEST FCST SNOWFALL TOTALS ARE WITHIN REACH. INTENSE BAND IS LOCATED ALONG I-81 CORRIDOR PRESENTLY WITH 1/2-3/4SM VISIBILITIES IN THIS BAND. HAVE AVGD AN INCH PER HOUR FOR THE PAST 6 HRS HERE AT THE OFFICE AND EXPECT THIS TO CONTINUE UNTIL APPROX 12Z. THE BIG MONKEY WRENCH IN THIS FCST IS THE DRY SLOT WRAPPING INTO NEPA. THIS IS SLOWLY WORKING ITS WAY WEST...A LITTLE FURTHER THAN ORIGINALLY THOUGHT. HOWEVER...NAM CONSISTENTLY SHOWED QPF SLACKING OFF ACROSS THE AREA THIS MORNING. WHILE THERE WAS SOME CONCERN THIS WUD BRING PCPN TO AN END QUICKER THAN FIRST THOUGHT EAST OF THE I-81 CORRIDOR...LATEST RADAR IMAGES SHOW PCPN CONTINUALLY DEVELOPING. THUS...HAVE KEPT HEAVY SNOW IN FOR GOOD PART OF THE DAY FOR ALONG AND WEST OF I-81. SNOWFALL TOTALS LOOKS TO RANGE ANYWHERE FROM 4-12 INCHES...LOWEST IN THE VALLEYS AND HIGHEST ON THE HILLTOPS. OTHER MAJOR CONCERN IS FLOODING IN THE WRN CATSKILLS TODAY. TWO TO THREE INCHES OF RAIN FELL IN THESE AREAS OVER THE PAST 24 HRS. CUD SEE ADDNL AMOUNTS OF NR AN INCH THROUGH NOON TODAY...LEADING TO CONTINUED THREAT FOR FLOODING. ALREADY HAVE NUMEROUS REPORTS OF ROADS CLOSED IN DELAWARE AND SULLIVAN COUNTIES. THUS WITH THE LATEST MODEL GUIDANCE AND CURRENT TRENDS...HAVE DROPPED WINTER WX ADVISORY FOR PIKE AND SULLIVAN WITH ONLY A COUPLE OF INCHES EXPECTED OVER THE FAR WEST. DELAWARE WAS A TRICKIER CALL WITH RAIN IN THE EAST AND SNOW IN THE WEST. OPTED TO LEAVE THE WINTER STORM WARNING GOING BUT PROBABLY ONLY LOOKING AT 5-8 INCH (MINIMAL WARNING) AMOUNTS. HAVE ALSO CUT DOWN ON SNOWFALL ACCUMS OVER EASTERN ONEIDA AS NAM/RUC BRING 850/800MB TEMPS > 0C INTO THIS AREA THIS MORNING. THIS WILL LIKELY LEAD TO A SNOW/RAIN/SLEET MIX FOR A TIME AND REDUCE AMOUNTS TO CLOSER TO A 4-8 INCH RANGE OVER THE FAR EAST. ALL IN ALL...TAPERED DOWN AMOUNTS MOST AREAS FOR STORM TOTALS. HIGHEST AMOUNTS STILL EXPECTED ALONG THE I-81 CORRIDOR WITH THE MOST INTENSE RATES THRU 12Z. ACCUM PAST THAT POINT MAY BE HARD TO COME BY UNLESS SNOW CAN FALL AT AN EXTREMELY INTENSE RATE. HOWEVER...SNOW WILL BE FALLING ON EXISTING SNOW COVER SO MAY BE EASIER TO ACCUMULATE THAN IF IT WERE FALLING ON BARE GROUND. LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AN OMEGA BLOCK PATTERN IS FORECAST TO SET UP ACROSS THE CONUS EARLY IN THIS PERIOD...THEN BREAK DOWN BY THE WEEKEND...RETURNING US TO MORE SEASONABLE CONDITIONS. IT IS POSSIBLE THAT THE MODELS ARE BREAKING THIS PATTERN DOWN A DAY OR SO TOO SOON...BUT AT THE MOMENT THIS IS NOT READILY EVIDENT IN OPERATIONAL RUNS OF THE GFS OR THE MREF ENSEMBLES. GIVEN THIS EXPECTED PATTERN EVOLUTION...CLOUDS AND BELOW NORMAL TEMPERATURES WILL PERSIST WEDS-THURS UNDER THE WESTERN INFLUENCE OF UPPER LOW. LATEST MEX GUIDANCE LOOKS COOLER AND MORE REASONABLE WITH THE ENSEMBLE 925 MB T PREDICTIONS...OR THE HPC FCSTS SO WILL LEAN CLOSE TO THE MEX WEDS-THURS. THE RIDGING BEGINS TO DEVELOP FRI...WITH SWLY FLOW THEN DEVELOPING LATER IN THE WEEKEND SO MORE SUNSHINE IS PLANNED FOR THE WEEKEND ALONG WITH TEMPS NEAR OR SLGHTLY ABOVE NORMAL. HPC/MEX GUIDANCE BLEND SEEMS REASONABLE DAYS 6-7. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ009- 015>018-022>025-036-037-044>046-055>057. PA...WINTER STORM WARNING UNTIL 8 PM EDT THIS EVENING FOR PAZ038- 039-043. WINTER WEATHER ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ040- 044-047-072. && $$ SHORT TERM...JAB ny AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BINGHAMTON NY 725 AM EDT MON APR 16 2007 .AVIATION /161200Z-171200Z/... DEEP CYCLONE CONTINUES TO PRODUCE SNOW OVER ALL TERMINALS THIS MORNING. LIFR/IFR VSBYS PREDOMINANT FOR NEXT FEW HRS IN MOST INTENSE SNOW BANDS. CIGS/VSBYS GRADUALLY RISE TO MVFR DRNG THE AFTERNOON WITH A LITTLE MORE MIXING OCCURRING. HOWEVER INTENSE MESOSCALE SNOW BAND CUD LEAD TO BRIEF PERIODS OF LIFR CONDS THRU 18Z...ESPECIALLY IN KSYR/KBGM/KITH AND KELM. SNOW SHOWERS BECOME SCTD ACROSS MOST TERMINALS AFTER 00Z. NORTHWEST WINDS BTWN 10-20KTS WITH GUSTS OF 25-35KTS EXPECTED THRU 01Z BEFORE SLOWLY DIMINISHING. && .PREV DISCUSSION... /ISSUED 453 AM EDT MON APR 16 2007/ SHORT TERM /TODAY THROUGH TUESDAY/... NOREASTER CONTINUES TO BLANKET UPSTATE NY AND NEPA WITH SNOW/HEAVY RAIN. 971MB SFC LOW IS SITTING NEAR THE NY BIGHT THIS MORNING AND FLINGING SIGNIFICANT WRAP-AROUND BACK INTO THE FA. SNOWFALL REPORTS ON AVG RUNNING ARND SIX INCHES AT THE HIGHER ELEVATIONS TO BTWN 2-3 IN THE VALLEYS. NOTHING SIGNIFICANT BY ANY STRETCH OF THE IMAGINATION BUT THINK LATEST FCST SNOWFALL TOTALS ARE WITHIN REACH. INTENSE BAND IS LOCATED ALONG I-81 CORRIDOR PRESENTLY WITH 1/2-3/4SM VISIBILITIES IN THIS BAND. HAVE AVGD AN INCH PER HOUR FOR THE PAST 6 HRS HERE AT THE OFFICE AND EXPECT THIS TO CONTINUE UNTIL APPROX 12Z. THE BIG MONKEY WRENCH IN THIS FCST IS THE DRY SLOT WRAPPING INTO NEPA. THIS IS SLOWLY WORKING ITS WAY WEST...A LITTLE FURTHER THAN ORIGINALLY THOUGHT. HOWEVER...NAM CONSISTENTLY SHOWED QPF SLACKING OFF ACROSS THE AREA THIS MORNING. WHILE THERE WAS SOME CONCERN THIS WUD BRING PCPN TO AN END QUICKER THAN FIRST THOUGHT EAST OF THE I-81 CORRIDOR...LATEST RADAR IMAGES SHOW PCPN CONTINUALLY DEVELOPING. THUS...HAVE KEPT HEAVY SNOW IN FOR GOOD PART OF THE DAY FOR ALONG AND WEST OF I-81. SNOWFALL TOTALS LOOKS TO RANGE ANYWHERE FROM 4-12 INCHES...LOWEST IN THE VALLEYS AND HIGHEST ON THE HILLTOPS. OTHER MAJOR CONCERN IS FLOODING IN THE WRN CATSKILLS TODAY. TWO TO THREE INCHES OF RAIN FELL IN THESE AREAS OVER THE PAST 24 HRS. CUD SEE ADDNL AMOUNTS OF NR AN INCH THROUGH NOON TODAY...LEADING TO CONTINUED THREAT FOR FLOODING. ALREADY HAVE NUMEROUS REPORTS OF ROADS CLOSED IN DELAWARE AND SULLIVAN COUNTIES. THUS WITH THE LATEST MODEL GUIDANCE AND CURRENT TRENDS...HAVE DROPPED WINTER WX ADVISORY FOR PIKE AND SULLIVAN WITH ONLY A COUPLE OF INCHES EXPECTED OVER THE FAR WEST. DELAWARE WAS A TRICKIER CALL WITH RAIN IN THE EAST AND SNOW IN THE WEST. OPTED TO LEAVE THE WINTER STORM WARNING GOING BUT PROBABLY ONLY LOOKING AT 5-8 INCH (MINIMAL WARNING) AMOUNTS. HAVE ALSO CUT DOWN ON SNOWFALL ACCUMS OVER EASTERN ONEIDA AS NAM/RUC BRING 850/800MB TEMPS > 0C INTO THIS AREA THIS MORNING. THIS WILL LIKELY LEAD TO A SNOW/RAIN/SLEET MIX FOR A TIME AND REDUCE AMOUNTS TO CLOSER TO A 4-8 INCH RANGE OVER THE FAR EAST. ALL IN ALL...TAPERED DOWN AMOUNTS MOST AREAS FOR STORM TOTALS. HIGHEST AMOUNTS STILL EXPECTED ALONG THE I-81 CORRIDOR WITH THE MOST INTENSE RATES THRU 12Z. ACCUM PAST THAT POINT MAY BE HARD TO COME BY UNLESS SNOW CAN FALL AT AN EXTREMELY INTENSE RATE. HOWEVER...SNOW WILL BE FALLING ON EXISTING SNOW COVER SO MAY BE EASIER TO ACCUMULATE THAN IF IT WERE FALLING ON BARE GROUND. LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AN OMEGA BLOCK PATTERN IS FORECAST TO SET UP ACROSS THE CONUS EARLY IN THIS PERIOD...THEN BREAK DOWN BY THE WEEKEND...RETURNING US TO MORE SEASONABLE CONDITIONS. IT IS POSSIBLE THAT THE MODELS ARE BREAKING THIS PATTERN DOWN A DAY OR SO TOO SOON...BUT AT THE MOMENT THIS IS NOT READILY EVIDENT IN OPERATIONAL RUNS OF THE GFS OR THE MREF ENSEMBLES. GIVEN THIS EXPECTED PATTERN EVOLUTION...CLOUDS AND BELOW NORMAL TEMPERATURES WILL PERSIST WEDS-THURS UNDER THE WESTERN INFLUENCE OF UPPER LOW. LATEST MEX GUIDANCE LOOKS COOLER AND MORE REASONABLE WITH THE ENSEMBLE 925 MB T PREDICTIONS...OR THE HPC FCSTS SO WILL LEAN CLOSE TO THE MEX WEDS-THURS. THE RIDGING BEGINS TO DEVELOP FRI...WITH SWLY FLOW THEN DEVELOPING LATER IN THE WEEKEND SO MORE SUNSHINE IS PLANNED FOR THE WEEKEND ALONG WITH TEMPS NEAR OR SLGHTLY ABOVE NORMAL. HPC/MEX GUIDANCE BLEND SEEMS REASONABLE DAYS 6-7. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ009- 015>018-022>025-036-037-044>046-055>057. FLOOD WATCH UNTIL NOON EDT TODAY FOR NYZ057-062. PA...WINTER STORM WARNING UNTIL 8 PM EDT THIS EVENING FOR PAZ038- 039-043. WINTER WEATHER ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ040- 044-047-072. FLOOD WATCH UNTIL NOON EDT TODAY FOR PAZ048. && $$ AVIATION...PB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 453 AM EDT MON APR 16 2007 .SHORT TERM /TODAY THROUGH TUESDAY/... NOREASTER CONTINUES TO BLANKET UPSTATE NY AND NEPA WITH SNOW/HEAVY RAIN. 971MB SFC LOW IS SITTING NEAR THE NY BIGHT THIS MORNING AND FLINGING SIGNIFICANT WRAP-AROUND BACK INTO THE FA. SNOWFALL REPORTS ON AVG RUNNING ARND SIX INCHES AT THE HIGHER ELEVATIONS TO BTWN 2-3 IN THE VALLEYS. NOTHING SIGNIFICANT BY ANY STRETCH OF THE IMAGINATION BUT THINK LATEST FCST SNOWFALL TOTALS ARE WITHIN REACH. INTENSE BAND IS LOCATED ALONG I-81 CORRIDOR PRESENTLY WITH 1/2-3/4SM VISIBILITIES IN THIS BAND. HAVE AVGD AN INCH PER HOUR FOR THE PAST 6 HRS HERE AT THE OFFICE AND EXPECT THIS TO CONTINUE UNTIL APPROX 12Z. THE BIG MONKEY WRENCH IN THIS FCST IS THE DRY SLOT WRAPPING INTO NEPA. THIS IS SLOWLY WORKING ITS WAY WEST...A LITTLE FURTHER THAN ORIGINALLY THOUGHT. HOWEVER...NAM CONSISTENTLY SHOWED QPF SLACKING OFF ACROSS THE AREA THIS MORNING. WHILE THERE WAS SOME CONCERN THIS WUD BRING PCPN TO AN END QUICKER THAN FIRST THOUGHT EAST OF THE I-81 CORRIDOR...LATEST RADAR IMAGES SHOW PCPN CONTINUALLY DEVELOPING. THUS...HAVE KEPT HEAVY SNOW IN FOR GOOD PART OF THE DAY FOR ALONG AND WEST OF I-81. SNOWFALL TOTALS LOOKS TO RANGE ANYWHERE FROM 4-12 INCHES...LOWEST IN THE VALLEYS AND HIGHEST ON THE HILLTOPS. OTHER MAJOR CONCERN IS FLOODING IN THE WRN CATSKILLS TODAY. TWO TO THREE INCHES OF RAIN FELL IN THESE AREAS OVER THE PAST 24 HRS. CUD SEE ADDNL AMOUNTS OF NR AN INCH THROUGH NOON TODAY...LEADING TO CONTINUED THREAT FOR FLOODING. ALREADY HAVE NUMEROUS REPORTS OF ROADS CLOSED IN DELAWARE AND SULLIVAN COUNTIES. THUS WITH THE LATEST MODEL GUIDANCE AND CURRENT TRENDS...HAVE DROPPED WINTER WX ADVISORY FOR PIKE AND SULLIVAN WITH ONLY A COUPLE OF INCHES EXPECTED OVER THE FAR WEST. DELAWARE WAS A TRICKIER CALL WITH RAIN IN THE EAST AND SNOW IN THE WEST. OPTED TO LEAVE THE WINTER STORM WARNING GOING BUT PROBABLY ONLY LOOKING AT 5-8 INCH (MINIMAL WARNING) AMOUNTS. HAVE ALSO CUT DOWN ON SNOWFALL ACCUMS OVER EASTERN ONEIDA AS NAM/RUC BRING 850/800MB TEMPS > 0C INTO THIS AREA THIS MORNING. THIS WILL LIKELY LEAD TO A SNOW/RAIN/SLEET MIX FOR A TIME AND REDUCE AMOUNTS TO CLOSER TO A 4-8 INCH RANGE OVER THE FAR EAST. ALL IN ALL...TAPERED DOWN AMOUNTS MOST AREAS FOR STORM TOTALS. HIGHEST AMOUNTS STILL EXPECTED ALONG THE I-81 CORRIDOR WITH THE MOST INTENSE RATES THRU 12Z. ACCUM PAST THAT POINT MAY BE HARD TO COME BY UNLESS SNOW CAN FALL AT AN EXTREMELY INTENSE RATE. HOWEVER...SNOW WILL BE FALLING ON EXISTING SNOW COVER SO MAY BE EASIER TO ACCUMULATE THAN IF IT WERE FALLING ON BARE GROUND. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AN OMEGA BLOCK PATTERN IS FORECAST TO SET UP ACROSS THE CONUS EARLY IN THIS PERIOD...THEN BREAK DOWN BY THE WEEKEND...RETURNING US TO MORE SEASONABLE CONDITIONS. IT IS POSSIBLE THAT THE MODELS ARE BREAKING THIS PATTERN DOWN A DAY OR SO TOO SOON...BUT AT THE MOMENT THIS IS NOT READILY EVIDENT IN OPERATIONAL RUNS OF THE GFS OR THE MREF ENSEMBLES. GIVEN THIS EXPECTED PATTERN EVOLUTION...CLOUDS AND BELOW NORMAL TEMPERATURES WILL PERSIST WEDS-THURS UNDER THE WESTERN INFLUENCE OF UPPER LOW. LATEST MEX GUIDANCE LOOKS COOLER AND MORE REASONABLE WITH THE ENSEMBLE 925 MB T PREDICTIONS...OR THE HPC FCSTS SO WILL LEAN CLOSE TO THE MEX WEDS-THURS. THE RIDGING BEGINS TO DEVELOP FRI...WITH SWLY FLOW THEN DEVELOPING LATER IN THE WEEKEND SO MORE SUNSHINE IS PLANNED FOR THE WEEKEND ALONG WITH TEMPS NEAR OR SLGHTLY ABOVE NORMAL. HPC/MEX GUIDANCE BLEND SEEMS REASONABLE DAYS 6-7. && .AVIATION /06Z-06Z/... MAJOR WINTER STORM AFFECTING ALL TAF SITES WITH OCCASIONALLY HEAVY SNOW DURING THE OVERNIGHT AND THRU THE MORNING HOURS. CONDITIONS WILL OBVIOUSLY BE QUITE LOW DURING MOST OF THE TAF PERIOD...WITH IFR AT BEST THRU AT LEAST EARLY AFTN TODAY. SNOW WILL BEGIN TO TAPER OFF TO SHSN ESP ACROSS AVP AND ELM BY LATE AFTN WITH SOME IMPROVEMENT TO MVFR POSSIBLE AT ALL SITES BY EARLY EVENING. ANOTHER BIG FACTOR WILL BE THE WINDS. INCREASING NORTHERLY WINDS OVERNIGHT TO 15 TO 25 KTS BY DAYBREAK. NWLY WINDS 15 TO 20 KTS WITH GUSTS TO 35 KTS OR HIGHER PSBLE DURING THE DAY TODAY. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ009- 015>018-022>025-036-037-044>046-055>057. FLOOD WATCH UNTIL NOON EDT TODAY FOR NYZ057-062. PA...WINTER STORM WARNING UNTIL 8 PM EDT THIS EVENING FOR PAZ038- 039-043. WINTER WEATHER ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ040- 044-047-072. FLOOD WATCH UNTIL NOON EDT TODAY FOR PAZ048. && $$ SHORT TERM...PVB LONG TERM...JAB AVIATION...JML ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 225 PM EDT SUN APR 15 2007 .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AN OMEGA BLOCK PATTERN IS FORECAST TO SET UP ACROSS THE CONUS EARLY IN THIS PERIOD...THEN BREAK DOWN BY THE WEEKEND...RETURNING US TO MORE SEASONABLE CONDITIONS. IT IS POSSIBLE THAT THE MODELS ARE BREAKING THIS PATTERN DOWN A DAY OR SO TOO SOON...BUT AT THE MOMENT THIS IS NOT READILY EVIDENT IN OPERATIONAL RUNS OF THE GFS OR THE MREF ENSEMBLES. GIVEN THIS EXPECTED PATTERN EVOLUTION...CLOUDS AND BELOW NORMAL TEMPERATURES WILL PERSIST WEDS-THURS UNDER THE WESTERN INFLUENCE OF UPPER LOW. LATEST MEX GUIDANCE LOOKS COOLER AND MORE REASONABLE WITH THE ENSEMBLE 925 MB T PREDICTIONS...OR THE HPC FCSTS SO WILL LEAN CLOSE TO THE MEX WEDS-THURS. THE RIDGING BEGINS TO DEVELOP FRI...WITH SWLY FLOW THEN DEVELOPING LATER IN THE WEEKEND SO MORE SUNSHINE IS PLANNED FOR THE WEEKEND ALONG WITH TEMPS NEAR OR SLGHTLY ABOVE NORMAL. HPC/MEX GUIDANCE BLEND SEEMS REASONABLE DAYS 6-7. && .AVIATION /18Z-18Z/... POWERFUL UPPER LEVEL TROF MOVING FROM TN VALLEY TO CAROLINAS WILL CONTINUE TO RAPIDLY...AND VIGOROUSLY INTENSIFY THROUGH MONDAY MORNING AS IT SLOWLY PIVOTS NORTHEAST. NEW SFC LOW PRESSURE FORMING THIS AFTERNOON NEAR DELMARVA WILL BECOME PRIMARY. THESE ARE ALL SIGNS THAT FORECAST IS NOW COMING TOGETHER FOR A MAJOR NOREASTER TONIGHT AND MONDAY WITH EXTREMELY DANGEROUS FLYING CONDITIONS ACROSS CNY. RAIN MIXING WITH SNOW EXPECTED THROUGH 00Z WITH FLUCTUATING MVFR-IFR CIGS/VSBYS. THEN...INTENSE UPWARD MOTION DEVELOPS NORTH OF STORM SYSTEM CHANGING PRECIP TO HEAVY SNOW AND ASSOCIATED IFR-LIFR CONDITIONS FOR SYR-ITH-ELM-BGM-RME. BEST LOCATION FOR FLIGHT OPS IN MY REGION WILL BE AVP WHERE COLD AIR ARRIVES VERY LATE. EVEN SOMEWHAT OF A DRY SLOT COULD KEEP PRECIP LIGHTER AT AVP THROUGH 12Z...SO GENERALLY WENT MVFR HERE. WILL KEEP THE VERY POOR LIFR CATEGORY IN MDT SNOW GOING THROUGH THE END OF FCST PERIOD...AS MDLS SHOW LITTLE SIGNS OF CHANGE IN STORM INTENSITY THRU 18Z. THERE WILL PROBABLY BE CATEGORY BOUNCES AS USUAL...BUT OVERALL NEXT 24 HOURS OF FLIGHT OPS WILL BE VERY POOR. && .PREV DISCUSSION... /ISSUED 1015 AM EDT SUN APR 15 2007/ SHORT TERM /REST OF TODAY/... HAVE ISSUED A FLOOD WATCH FOR SE ZONES FOR TODAY. RAINFALL AMOUNTS SINCE MIDNIGHT HAVE RANGED FROM 0.50-0.75 INCHES IN THESE AREAS AS A LARGE AREA OF MOISTURE SPREADS NORTH IN SOUTHWEST FLOW ALOFT. H8 LLJ OF 40-50KTS ALREADY CRANKING ACROSS THE DELMARVA AND THIS WILL INCREASE DRNG THE DAY OVER NEPA/SENY. WINDS WILL REMAIN OUT OF THE SOUTHEAST AS LOW PRESSURE SYSTEM EXITS OFFSHORE MD THIS AFTERNOON. THIS WILL ENHANCE RAINFALL AMOUNTS DUE TO OROGRAPHIC LIFT. RUC/GFS/NAM ALL BRING SLUG OF MOISTURE INTO THESE AREAS UNTIL 21Z- 00Z TODAY. COULD SEE TOTAL RAINFALL IN THE ORDER OF 1-2 INCHES WITH AN ISOLD 3 INCHES POSSIBLE IN GREATER LIFT. THIS COULD BRING SOME RISES ON DELAWARE AND PA PORTION OF THE SUSQUEHANNA RIVER WITH THESE AMOUNTS. CURRENT RIVER PROJECTIONS ARE 1/2 TO 3/4 BANKFULL BUT EXTRA RAIN COULD LEAD TO SOME MINOR FLOODING. WILL KEEP AN EYE ON RAINFALL TOTALS IN THE AREA AND RIVER RESPONSES. AS FOR THE REST OF THE AREA AND THE WINTER STORM EXPECTED. 993MB SFC LOW LOCATED NEAR HICKORY NORTH CAROLINA IN THE WRN HALF OF THE STATE. GREATEST PRESSURE FALLS ARE CENTERED OFF THE DELMARVA PENINSULA...INDICATING A NORTHEASTWARD MOVEMENT TO THE SYSTEM TODAY. RUC/NAM/GFS/NGM/ECMWF ALL AGREE ON THIS INITIAL MOVEMENT. AFTER THIS POINT...GFS DEEPENS LOW MORE THAN NAM OFF THE EAST COAST LATER TONIGHT. GFS DOWN TO 973MB AND MAN DEEPENS LOW TO 975MB BY 12Z MONDAY. BOTH ARE ALSO IN GOOD AGREEMENT WITH CLOSING OFF AND DEEPENING H5 LOW OVERNIGHT WITH GFS DEEPER THAN NA, BUT IN RELATIVELY THE SAME POSITION. AS FOR H7 LOW...GFS IS OBVIOUSLY DEEPER BUT BOTH TRACK IT ACROSS CENTRAL NJ OVERNIGHT JUST TO OUR SOUTH AND EAST. BASED ON FCST POSITION OF MASS FIELDS...CURRENT WARNING LOOKS EXCELLENT. GFS SHOWING BANDING OVER I-81 CORRIDOR TONIGHT AS DOES THE NAM. STILL THINK FINGER LAKES AND MOHAWK VALLEY ARE MOST LIKELY AREAS TO SEE THE HEAVIEST SNOW BUT A WOBBLE TO THE EAST DOES PUT I-81 CORRIDOR IN THE BEST BAND. STILL A QUESTION AS TO THERMAL PROFILES THIS AFTERNOON. 06Z NAM IS COLDER THAN 06Z GFS AS GFS KEEPS MOSTLY RAIN OVER THE ENTIRE AREA UNTIL AFTER 00Z. WILL TEND TO SIDE TOWARD NAM PROFILE AS KSYR HAS SWITCHED OVER TO SNOW. EXPECT THIS TO WAVER BACK AND FORTH BTWN RA/SN UNTIL 18Z-21Z AND THEN SWITCH OVER TO ALL SNOW...21Z-00Z OVER SRN TIER. LATEST 12Z GUIDANCE FROM THE NAM STILL SUGGESTING MESOSCALE BAND ALONG I-81 CORRIDOR OVERNIGHT ALL THE WAY INTO NEPA. WILL EVALUATE THIS POTENTIAL AND WHAT IMPACT THIS WILL HAVE ON SNOWFALL ACCUMS AND OUR CURRENT HEADLINES. NOT MAKING CHGS AT THIS TIME UNTIL WE GET BETTER HANDLE ON THIS. PREV DISCUSSION... /ISSUED 742 AM EDT SUN APR 15 2007/ AVIATION /12Z-12Z/... PREDOMINANT IFR CONDITIONS ASSOCIATED WITH A MIX OF SNOW AND RAIN WILL PERSIST ACROSS THE FLIGHT AREA TODAY. AVP AND RME STARTING OFF MVFR BUT SHOULD ALSO LOWER CIGS TO IFR CATEGORY BY THIS AFTERNOON. RAIN CHANGES TO SNOW THROUGH THE AFTERNOON AND PIVOTS BACK TOWARD WESTERN NY...BUT DAYLIGHT ACCUMULATIONS EXPECTED TO BE RELATIVELY NIL. SNOW THEN BECOMES HEAVIER TONIGHT AS PRIMARY COASTAL LOW RAPIDLY DEEPENS AND DRAWS COLDER AIR INTO THE SYSTEM. EXCEPTION BEING AVP WHERE RAIN LIKELY TO BE PREDOMINANT TYPE THROUGHOUT THE EVENT. SNOWFALL RATES WILL INCREASE FOR SEVERAL HOURS TONIGHT...WITH IFR-LIFR CIGS/VSBYS DEVELOPING. HEAVY AND WET ACCUMULATING SNOW LIKELY ON RUNWAYS AND TARMACS ACROSS UPSTATE NY TERMINALS TONIGHT AND MONDAY. PREV DISCUSSION... /ISSUED 323 AM EDT SUN APR 15 2007/ UPDATE... MADE MINOR CHANGES TO ADVISORY/WARNING AREAS OVER NYS. PREV DISCUSSION... /ISSUED 312 AM EDT SUN APR 15 2007/ SHORT TERM /TODAY THROUGH MONDAY NIGHT/... MAJOR EARLY SPRING STORM WILL TRACK UP THE EAST COAST LATER TONIGHT, TO NEAR LONG ISLAND BY MONDAY MORNING. A MIX OF RAIN AND SNOW WILL SPREAD TOWARD THE NEW YORK AND PENNSYLVANIA STATE BORDERS THROUGH THIS AFTERNOON, THEN GRADUALLY CHANGE OVER TO ALL SNOW OVER MUCH OF CENTRAL NEW YORK DURING THE LATE AFTERNOON AS TEMPERATURES COOL. HAVE PUT THE FINAL TOUCHES ON THE MOST CHALLENGING FORECAST WE HAVE HAD IN A LONG TIME. THE NORTHERN TIER OF PA HAS BEEN FLAGGED FOR A WINTER WX ADVISORY, AS HAS SULLIVAN NY. WE EXTENDED THE WARNED AREA SOUTH THROUGH TIOGA-BROOME-DELAWARE COUNTIES OF NY. WET SNOW IS MIXING WITH THE RAIN STREAMING NORTH AHEAD OF THE MOIST AIR PUSH. SOME OF THE SNOW IS STARTING TO ACCUMULATE ON GRASSY SURFACES, ESPECIALLY ON THE HILLTOPS. HOWEVER WARM ADVECTION AND THE RISING OF THE SUN SHOULD SWITCH ALL THE PRECIPITATION OVER TO RAIN BY 8 AM. THE RAIN WILL CONTINUE THROUGH MIDDAY, AS COLDER AIR STARTS TO WORK ITS WAY INTO WESTERN NY. THIS WILL CAUSE THE HIGH ELEVATIONS TO START CHANGING OVER TO SNOW MIDDAY, WITH THE URBAN VALLEYS LIKELY STAYING ALL RAIN UNTIL LATE AFTERNOON. WHILE THE MODELS FORECASTS HAVE GONE THROUGH LARGE CHANGES LAST 48H AND HAVE NOT BEEN IN VERY GOOD AGREEMENT, ONE IMPORTANT POINT THEY ALL SEEM TO HAVE MADE IS THAT UPWARD MOTION WILL BECOME RATHER INTENSE LATE AFTERNOON INTO EARLY EVENING. THE COOL/MOIST ATLANTIC AIR WRAPPING AROUND THE NORTHEAST SIDE OF THE INTENSIFYING CYCLONE WILL RESULT IN FRONTOGENETIC FORCING. THIS SHOWS UP WITH INTENSE OMEGA FIELDS. THE ONE NEGATIVE IN THE EQUATION IS THE LIFT IS BELOW THE UNDERSTANDABLY ELEVATED SNOW GROWTH REGION. STILL THE LIFT IS SO STRONG, I EXPECT RAPID COOLING TO TAKE PLACE, AND SNOWFALL RATES TO INCREASE TO UPWARDS OF 1 INCH PER HOUR IN EMBEDDED SQUALLS. THE BEST FORCING REMAINS FIXED OVER THE NORTHEASTERN FORECAST AREA FOR MUCH OF THE OVERNIGHT HOURS AND THROUGH EARLY MONDAY. THIS SHOULD LEAD TO 10-16 INCHES OF SNOW ACCUMULATION, WITH 6-10 INCHES ALONG THE NYS/PA BORDER. IT APPEARS THE WILKES BARRE - SCRANTON AREA WILL REMAIN WARM ENOUGH TO PRECLUDE HEAVY SNOW. LOOK FOR THIS AREA TO TACK ON AN INCH OR TWO OVERNIGHT. DP/BGM LONG TERM /TONIGHT THROUGH SATURDAY/... MAJOR CYCLONE OCCLUDES OVER THE NEW ENGLAND STATES EARLY THIS PERIOD...WHICH THEN LEADS TO A SPRING TIME OMEGA BLOCK DEVELOPING ACROSS THE CONUS DURING THE WEEK...WHICH ONLY GRADUALLY LOOSENS IT/S GRIP TOWARD THE WEEKEND. THIS WILL MAINTAIN THE BELOW NORMAL TEMPERATURES THROUGH THE WEEK. PLENTY OF LOW LEVEL CLOUD COVER WILL LINGER IN NORTHWEST FLOW BEHIND THE STORM SYSTEM FROM TUESDAY THROUGH THURSDAY...WITH GRADUAL INCREASES OF SUNSHINE BY SATURDAY. AFTER LINGERING SNOW SHOWERS IN NW UPSLOPE FLOW THROUGH TUESDAY NIGHT...ANY PRECIPITATION CHANCE FOR THE REST OF THE WEEK LOOKS NIL AT THIS POINT. WENT WITH MOST OF HPC GUIDANCE EXCEPT HAD TO MAKE MAJOR CHANGES TO EXPECTED CLOUD COVER...AND RESULTANT TEMPS PER LATEST 06Z AND 12Z GFS MEAN RH AND THERMAL PROG TRENDS. DROPPED ABOUT 5-6 DEGREES OFF HPC/MEX GUIDANCE ON TUESDAY THROUGH WEDNESDAY...AS MIXING UP TO 925 MB TEMPS ARE NOT SUPPORTIVE OF MOS/HPC GUIDANCE IN THE 40S-50S...ESPECIALLY OVER A SNOW PACK AND OVERCAST SKIES. ALSO CONTINUED WITH A COOLER TREND RIGHT THROUGH SATURDAY...PER ENSEMBLE MOS GUIDANCE AND ADIABATIC MIXING OF 2-4C AIR AT 925 MB. AVIATION /07Z-06Z/... MAJOR STORM HAS JUST BEGUN TO IMPACT THE AREA AND WILL CONTINUE TO DO SO THRU THE TAF PERIOD AND BEYOND. CONDITIONS WILL DETERIORATE QUICKLY WITH THE START OF PRECIPITATION, WHICH HAS ALREADY BEGUN AT MOST TAF SITES OR WILL IN THE FIRST COUPLE OF HOURS. PRECIP TYPE IS MAINLY RAIN WITH SNOW AT BGM. EXPECT MAINLY RAIN INTO THIS MORNING BEFORE A CHANGE OVER TO SNOW DURING THE AFTN, EXCEPT AT AVP WHERE RAIN SHOULD CONTINUE MOST OF THE DAY. MVFR CEILINGS AND OCCASIONALLY VISBY WILL LIKELY LOWER TO IFR DURING THE MORNING. EASTERLY WINDS GENERALLY LESS THAN 10 KTS WILL INCREASE THIS AFTN 10 TO 15 KTS. WINDS SWITCH TO NW EARLY THIS EVENING WITH INCREASE TO 15 TO 25 KTS WITH GUSTS 30 KTS. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 8 PM EDT MONDAY FOR NYZ009-015>018- 022>025-036-037-044>046-055>057. FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NYZ062. WINTER WEATHER ADVISORY UNTIL 8 PM EDT MONDAY FOR NYZ062. PA...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR PAZ044-047-048-072. WINTER WEATHER ADVISORY UNTIL 8 PM EDT MONDAY FOR PAZ038>040. && $$ LONG TERM...JAB AVIATION...JAB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1015 AM EDT SUN APR 15 2007 .SHORT TERM /REST OF TODAY/... HAVE ISSUED A FLOOD WATCH FOR SE ZONES FOR TODAY. RAINFALL AMOUNTS SINCE MIDNIGHT HAVE RANGED FROM 0.50-0.75 INCHES IN THESE AREAS AS A LARGE AREA OF MOISTURE SPREADS NORTH IN SOUTHWEST FLOW ALOFT. H8 LLJ OF 40-50KTS ALREADY CRANKING ACROSS THE DELMARVA AND THIS WILL INCREASE DRNG THE DAY OVER NEPA/SENY. WINDS WILL REMAIN OUT OF THE SOUTHEAST AS LOW PRESSURE SYSTEM EXITS OFFSHORE MD THIS AFTERNOON. THIS WILL ENHANCE RAINFALL AMOUNTS DUE TO OROGRAPHIC LIFT. RUC/GFS/NAM ALL BRING SLUG OF MOISTURE INTO THESE AREAS UNTIL 21Z- 00Z TODAY. COULD SEE TOTAL RAINFALL IN THE ORDER OF 1-2 INCHES WITH AN ISOLD 3 INCHES POSSIBLE IN GREATER LIFT. THIS COULD BRING SOME RISES ON DELAWARE AND PA PORTION OF THE SUSQUEHANNA RIVER WITH THESE AMOUNTS. CURRENT RIVER PROJECTIONS ARE 1/2 TO 3/4 BANKFULL BUT EXTRA RAIN COULD LEAD TO SOME MINOR FLOODING. WILL KEEP AN EYE ON RAINFALL TOTALS IN THE AREA AND RIVER RESPONSES. AS FOR THE REST OF THE AREA AND THE WINTER STORM EXPECTED. 993MB SFC LOW LOCATED NEAR HICKORY NORTH CAROLINA IN THE WRN HALF OF THE STATE. GREATEST PRESSURE FALLS ARE CENTERED OFF THE DELMARVA PENINSULA...INDICATING A NORTHEASTWARD MOVEMENT TO THE SYSTEM TODAY. RUC/NAM/GFS/NGM/ECMWF ALL AGREE ON THIS INITIAL MOVEMENT. AFTER THIS POINT...GFS DEEPENS LOW MORE THAN NAM OFF THE EAST COAST LATER TONIGHT. GFS DOWN TO 973MB AND MAN DEEPENS LOW TO 975MB BY 12Z MONDAY. BOTH ARE ALSO IN GOOD AGREEMENT WITH CLOSING OFF AND DEEPENING H5 LOW OVERNIGHT WITH GFS DEEPER THAN NA, BUT IN RELATIVELY THE SAME POSITION. AS FOR H7 LOW...GFS IS OBVIOUSLY DEEPER BUT BOTH TRACK IT ACROSS CENTRAL NJ OVERNIGHT JUST TO OUR SOUTH AND EAST. BASED ON FCST POSITION OF MASS FIELDS...CURRENT WARNING LOOKS EXCELLENT. GFS SHOWING BANDING OVER I-81 CORRIDOR TONIGHT AS DOES THE NAM. STILL THINK FINGER LAKES AND MOHAWK VALLEY ARE MOST LIKELY AREAS TO SEE THE HEAVIEST SNOW BUT A WOBBLE TO THE EAST DOES PUT I-81 CORRIDOR IN THE BEST BAND. STILL A QUESTION AS TO THERMAL PROFILES THIS AFTERNOON. 06Z NAM IS COLDER THAN 06Z GFS AS GFS KEEPS MOSTLY RAIN OVER THE ENTIRE AREA UNTIL AFTER 00Z. WILL TEND TO SIDE TOWARD NAM PROFILE AS KSYR HAS SWITCHED OVER TO SNOW. EXPECT THIS TO WAVER BACK AND FORTH BTWN RA/SN UNTIL 18Z-21Z AND THEN SWITCH OVER TO ALL SNOW...21Z-00Z OVER SRN TIER. LATEST 12Z GUIDANCE FROM THE NAM STILL SUGGESTING MESOSCALE BAND ALONG I-81 CORRIDOR OVERNIGHT ALL THE WAY INTO NEPA. WILL EVALUATE THIS POTENTIAL AND WHAT IMPACT THIS WILL HAVE ON SNOWFALL ACCUMS AND OUR CURRENT HEADLINES. NOT MAKING CHGS AT THIS TIME UNTIL WE GET BETTER HANDLE ON THIS. && .PREV DISCUSSION... /ISSUED 742 AM EDT SUN APR 15 2007/ AVIATION /12Z-12Z/... PREDOMINANT IFR CONDITIONS ASSOCIATED WITH A MIX OF SNOW AND RAIN WILL PERSIST ACROSS THE FLIGHT AREA TODAY. AVP AND RME STARTING OFF MVFR BUT SHOULD ALSO LOWER CIGS TO IFR CATEGORY BY THIS AFTERNOON. RAIN CHANGES TO SNOW THROUGH THE AFTERNOON AND PIVOTS BACK TOWARD WESTERN NY...BUT DAYLIGHT ACCUMULATIONS EXPECTED TO BE RELATIVELY NIL. SNOW THEN BECOMES HEAVIER TONIGHT AS PRIMARY COASTAL LOW RAPIDLY DEEPENS AND DRAWS COLDER AIR INTO THE SYSTEM. EXCEPTION BEING AVP WHERE RAIN LIKELY TO BE PREDOMINANT TYPE THROUGHOUT THE EVENT. SNOWFALL RATES WILL INCREASE FOR SEVERAL HOURS TONIGHT...WITH IFR-LIFR CIGS/VSBYS DEVELOPING. HEAVY AND WET ACCUMULATING SNOW LIKELY ON RUNWAYS AND TARMACS ACROSS UPSTATE NY TERMINALS TONIGHT AND MONDAY. PREV DISCUSSION... /ISSUED 323 AM EDT SUN APR 15 2007/ UPDATE... MADE MINOR CHANGES TO ADVISORY/WARNING AREAS OVER NYS. PREV DISCUSSION... /ISSUED 312 AM EDT SUN APR 15 2007/ SHORT TERM /TODAY THROUGH MONDAY NIGHT/... MAJOR EARLY SPRING STORM WILL TRACK UP THE EAST COAST LATER TONIGHT, TO NEAR LONG ISLAND BY MONDAY MORNING. A MIX OF RAIN AND SNOW WILL SPREAD TOWARD THE NEW YORK AND PENNSYLVANIA STATE BORDERS THROUGH THIS AFTERNOON, THEN GRADUALLY CHANGE OVER TO ALL SNOW OVER MUCH OF CENTRAL NEW YORK DURING THE LATE AFTERNOON AS TEMPERATURES COOL. HAVE PUT THE FINAL TOUCHES ON THE MOST CHALLENGING FORECAST WE HAVE HAD IN A LONG TIME. THE NORTHERN TIER OF PA HAS BEEN FLAGGED FOR A WINTER WX ADVISORY, AS HAS SULLIVAN NY. WE EXTENDED THE WARNED AREA SOUTH THROUGH TIOGA-BROOME-DELAWARE COUNTIES OF NY. WET SNOW IS MIXING WITH THE RAIN STREAMING NORTH AHEAD OF THE MOIST AIR PUSH. SOME OF THE SNOW IS STARTING TO ACCUMULATE ON GRASSY SURFACES, ESPECIALLY ON THE HILLTOPS. HOWEVER WARM ADVECTION AND THE RISING OF THE SUN SHOULD SWITCH ALL THE PRECIPITATION OVER TO RAIN BY 8 AM. THE RAIN WILL CONTINUE THROUGH MIDDAY, AS COLDER AIR STARTS TO WORK ITS WAY INTO WESTERN NY. THIS WILL CAUSE THE HIGH ELEVATIONS TO START CHANGING OVER TO SNOW MIDDAY, WITH THE URBAN VALLEYS LIKELY STAYING ALL RAIN UNTIL LATE AFTERNOON. WHILE THE MODELS FORECASTS HAVE GONE THROUGH LARGE CHANGES LAST 48H AND HAVE NOT BEEN IN VERY GOOD AGREEMENT, ONE IMPORTANT POINT THEY ALL SEEM TO HAVE MADE IS THAT UPWARD MOTION WILL BECOME RATHER INTENSE LATE AFTERNOON INTO EARLY EVENING. THE COOL/MOIST ATLANTIC AIR WRAPPING AROUND THE NORTHEAST SIDE OF THE INTENSIFYING CYCLONE WILL RESULT IN FRONTOGENETIC FORCING. THIS SHOWS UP WITH INTENSE OMEGA FIELDS. THE ONE NEGATIVE IN THE EQUATION IS THE LIFT IS BELOW THE UNDERSTANDABLY ELEVATED SNOW GROWTH REGION. STILL THE LIFT IS SO STRONG, I EXPECT RAPID COOLING TO TAKE PLACE, AND SNOWFALL RATES TO INCREASE TO UPWARDS OF 1 INCH PER HOUR IN EMBEDDED SQUALLS. THE BEST FORCING REMAINS FIXED OVER THE NORTHEASTERN FORECAST AREA FOR MUCH OF THE OVERNIGHT HOURS AND THROUGH EARLY MONDAY. THIS SHOULD LEAD TO 10-16 INCHES OF SNOW ACCUMULATION, WITH 6-10 INCHES ALONG THE NYS/PA BORDER. IT APPEARS THE WILKES BARRE - SCRANTON AREA WILL REMAIN WARM ENOUGH TO PRECLUDE HEAVY SNOW. LOOK FOR THIS AREA TO TACK ON AN INCH OR TWO OVERNIGHT. DP/BGM LONG TERM /TONIGHT THROUGH SATURDAY/... MAJOR CYCLONE OCCLUDES OVER THE NEW ENGLAND STATES EARLY THIS PERIOD...WHICH THEN LEADS TO A SPRING TIME OMEGA BLOCK DEVELOPING ACROSS THE CONUS DURING THE WEEK...WHICH ONLY GRADUALLY LOOSENS IT/S GRIP TOWARD THE WEEKEND. THIS WILL MAINTAIN THE BELOW NORMAL TEMPERATURES THROUGH THE WEEK. PLENTY OF LOW LEVEL CLOUD COVER WILL LINGER IN NORTHWEST FLOW BEHIND THE STORM SYSTEM FROM TUESDAY THROUGH THURSDAY...WITH GRADUAL INCREASES OF SUNSHINE BY SATURDAY. AFTER LINGERING SNOW SHOWERS IN NW UPSLOPE FLOW THROUGH TUESDAY NIGHT...ANY PRECIPITATION CHANCE FOR THE REST OF THE WEEK LOOKS NIL AT THIS POINT. WENT WITH MOST OF HPC GUIDANCE EXCEPT HAD TO MAKE MAJOR CHANGES TO EXPECTED CLOUD COVER...AND RESULTANT TEMPS PER LATEST 06Z AND 12Z GFS MEAN RH AND THERMAL PROG TRENDS. DROPPED ABOUT 5-6 DEGREES OFF HPC/MEX GUIDANCE ON TUESDAY THROUGH WEDNESDAY...AS MIXING UP TO 925 MB TEMPS ARE NOT SUPPORTIVE OF MOS/HPC GUIDANCE IN THE 40S-50S...ESPECIALLY OVER A SNOW PACK AND OVERCAST SKIES. ALSO CONTINUED WITH A COOLER TREND RIGHT THROUGH SATURDAY...PER ENSEMBLE MOS GUIDANCE AND ADIABATIC MIXING OF 2-4C AIR AT 925 MB. AVIATION /07Z-06Z/... MAJOR STORM HAS JUST BEGUN TO IMPACT THE AREA AND WILL CONTINUE TO DO SO THRU THE TAF PERIOD AND BEYOND. CONDITIONS WILL DETERIORATE QUICKLY WITH THE START OF PRECIPITATION, WHICH HAS ALREADY BEGUN AT MOST TAF SITES OR WILL IN THE FIRST COUPLE OF HOURS. PRECIP TYPE IS MAINLY RAIN WITH SNOW AT BGM. EXPECT MAINLY RAIN INTO THIS MORNING BEFORE A CHANGE OVER TO SNOW DURING THE AFTN, EXCEPT AT AVP WHERE RAIN SHOULD CONTINUE MOST OF THE DAY. MVFR CEILINGS AND OCCASIONALLY VISBY WILL LIKELY LOWER TO IFR DURING THE MORNING. EASTERLY WINDS GENERALLY LESS THAN 10 KTS WILL INCREASE THIS AFTN 10 TO 15 KTS. WINDS SWITCH TO NW EARLY THIS EVENING WITH INCREASE TO 15 TO 25 KTS WITH GUSTS 30 KTS. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER STORM WARNING UNTIL 8 PM EDT MONDAY FOR NYZ009-015>018- 022>025-036-037-044>046-055>057. FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NYZ062. WINTER WEATHER ADVISORY UNTIL 8 PM EDT MONDAY FOR NYZ062. PA...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR PAZ044-047-048-072. WINTER WEATHER ADVISORY UNTIL 8 PM EDT MONDAY FOR PAZ038>040. && $$ SHORT TERM...PVB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 830 PM CDT MON APR 16 2007 FORECAST CHALLENGE CONCERNS TEMPERATURES AND FOG POTENTIAL. SKIES HAVE ABOUT CLEARED OFF ACROSS FAR SE FA IN WAKE OF FRONTAL PASSAGE. REMAINDER OF NIGHT SHOULD SEE MAINLY CLEAR SKIES. WINDS ALSO DIMINISHING AND COMBINATION OF SKC AND WEAKENING SURFACE FLOW SHOULD RESULT IN GOOD RADIATIONAL COOLING. COOLEST MINIMUM TEMPERATURES EXPECTED ACROSS WEST IN DRIER AIR. RUC SLOW TO BRING IN REAL DRY AIR FROM THE WEST AND WITH DEWPOINTS ACROSS EAST IN MID 30S TO AROUND 40 WILL CONTINUE THOUGHT OF FOG POTENTIAL ALONG WITH WARMER TEMPERATURES. OVERALL CURRENT FORECAST SEEMS IN GOOD SHAPE SO ONLY MINOR ADJUSTMENTS PLANNED. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 723 AM EDT MON APR 16 2007 .SYNOPSIS... AN INTENSE COASTAL STORM...APPROACHING WESTERN LONG ISLAND THIS EVENING...WILL SLOW DOWN AND DOMINATE THE WEATHER THROUGH MID WEEK. FAIR WEATHER WILL RETURN FOR LATER IN THE WEEK WITH SLOWLY MODERATING TEMPERATURES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... QUITE A NIGHT SO FAR AS THE FEARED DEFORMATION ZONE MENTIONED LAST NIGHT AT THIS TIME MANAGED TO MATERIALIZE AND IS AFFECTING MY FAR EASTERN AND NORTHEASTERN ZONES. MUCH OF THE SNOW IS ELEVATION DEPENDENT WITH VALLEY LOCATIONS LIKE WILLIAMSPORT HANGING ON TO RAIN WITH TEMPS BETWEEN 35-40F. IT ALL IS COURTESY OF A COASTAL STORM THAT IS FINALLY UNDERGOING BOMBOGENESIS...DOWN TO 972MB AT 06Z...AFTER SEVERAL DAYS OF BUILD UP BY ANY OF A VARIETY OF FORECAST MODELS. IT UNFORTUNATELY (FORTUNATELY?) MANAGED TO HOLD OFF WITH THE BOTTOM FALLING OUT OF THE PRESSURE JUST LONG ENOUGH TO KEEP THE WETTEST AND COLDEST PARTS OF THE STORM FROM MANAGING TO COME INTO PHASE OVER THE LOCAL AREA. AS A RESULT WE SAW THE THREAT OF HEAVY SNOWS MORPH INTO A CHILLY WIDESPREAD MODERATE TO HEAVY RAIN. NOW ON THE BACK SIDE AS THE BOMB APPROACHES LOWER MANHATTAN...THE DEFORMATION ZONE CONTINUES TO DUMP ON MY FAR EASTERN ZONES. NAM/GFS BOTH SHOW INTENSE LOW-MID LEVEL FRONTOGENTIC FORCING CONTINUING THROUGH THE MORNING BEFORE BEGINNING TO WANE AROUND AND SHORTLY AFTER MID DAY. PERPLEXINGLY...THE HIGH RES RUC AND NAM12 SHOW THE BEST FGEN FORCING BEING CONFINED TO AREAS EAST OF MY FORECAST ZONES. THE RUC AT LEAST GENERATES IMPRESSIVE ASCENT AND CRANKS OUT ADDITIONAL PRECIP ON THE ORDER OF .20-.30 INCHES THROUGH MID MORNING OVER MY NERN ZONES. NAM12 KEEPS THE UPWARD VERT MOTION MORE CLOSELY TIED TO ITS LOW-MID LEVEL FRONTOGENESIS REGION...AND ALSO KEEPS BEST QPF EAST OF MY FCST AREA. SO THE LOWER RES MODELS SEEM TO HAVE A BETTER HANDLE AS THE EVENT CONTINUES. ACTIVITY SHOULD BEGIN TO WIND DOWN DURING THE LAST HALF OF THE DAY...BUT IT WILL BE A WILD WINDY ONE AS STRONG NORTHERLY GRADIENT CONTINUES AROUND THE STORM THAT IS FCST TO HEAD UP INTO SWRN CONNECTICUT BEFORE WOBBLING BACK OFF TO THE SOUTHEAST...ALL AS THE TRIPLE POINT OFFSHORE UNDERGOES DEVELOPMENT AND THE ENTIRE SYSTEM ROTATES AROUND JUT OFFSHORE FOR THE NEXT FEW DAYS. UNDER SUCH A REGIME WE WILL STAY CLOUDY AND UNSETTLED...ESPECIALLY OVER WESTERN AND NORTHERN HIGH TERRAIN. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... STRONG WIND WILL GRADUALLY DIMINISH AS THE OFFSHORE STORM STARTS TO FILL AND MOVE EAST. BUT IT WILL BE A MONSTER AND MAINTAIN ITS HOLD WITH COLD MOIST CYCLONIC FLOW AND OCCASIONAL LIGHT PRECIP. TUESDAY`S PRECIP PATTERN SHOULD BECOME ONE MORE RECOGNIZABLE OF A COLD SEASON POST CYCLONE/FRONTAL SYSTEM ONE...WHERE THE BEST CHANCE OF PRECIP WILL BE OVER WESTERN AND NORTHERN HIGH TERRAIN WITH DWINDLING CHANCES DOWNSTREAM AND DOWNSLOPE. MAINTAINED SLIGHTLY HIGHER POPS OVER MY NERN ZONES...A LITTLE CLOSER TO THE RESIDUAL MOISTURE THE PROGS HOLD ONTO ROTATING AROUND THE WESTERN PERIPHERY OF THE BIG STORM. THE BELOW NORMAL COLD WILL NOT GO ANYWHERE SOON. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... WEATHER WILL BE SLOW TO IMPROVE AS PERSISTENT COOL NORTHWEST FLOW CONTINUES THROUGH MID WEEK. WEAK WAVES WILL RIPPLE THROUGH THE FLOW KEEPING MENTION OF LOW POPS IN THE FORECAST AND A DECENT AMOUNT OF CLOUDS AROUND. MODELS AGREE IN A CHUNK OF THE UPPER AIR ENERGY CLOSING OFF INTO ANOTHER UPPER LOW OVER THE EASTERN GR LAKES OR OHIO VALLEY AROUND MIDWEEK WHICH WILL ONLY KEEP THE CHANCE OF LIGHT PRECIP IN THE FORECAST...DEPENDING ON EXACT TRACK OF THE SYSTEM. IT DOES LOOK LIKE SLOW IMPROVEMENT FOR THE END OF THE WEEK AND WEEKEND AS UPPER HEIGHTS SLOWLY RISE...BUT THE PATTERN IS PRETTY BLOCKY AND CONFIDENCE IS LOW THAT WE GET ON THE GOOD SIDE OF THE BLOCKING HIGH IN CANADA VS THE BAD SIDE OF THE LOW EAST OF HERE OR THE OTHER PROGGED OVER THE UPPER LAKES. THE MREF AND CAN ENS BOTH ARGUE FOR THE GOOD SIDE OF THE RIDGE SO I WILL BE AN OPTIMIST AND LOOK FORWARD TO THIS EXECRABLE "SPRING" WEATHER GOING AWAY. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... EXPECT MAINLY MVFR AND IFR CONDITIONS TODAY...AS RAIN AND SNOW BACK IN FROM THE EAST...AS AN INTENSE STORM REMAINS NEARLY STATIONARY. MAIN CONCERN WILL BE VERY STRONG WINDS INTO THIS AFT. IT WILL STILL BE BREEZY AND COOL INTO LATE WEEK...AS WE REMAIN ON THE EAST SIDE OF A HIGH...BUT SHOULD BE MAINLY VFR FROM WED INTO FRIDAY. && .CTP WATCHES/WARNINGS/ADVISORIES... HEAVY SNOW WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR PAZ037- 041-042. WIND ADVISORY UNTIL 6 PM EDT THIS AFTERNOON FOR PAZ004>006- 010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063>066. WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR PAZ046-051>053-058. WINTER WEATHER ADVISORY UNTIL NOON EDT TODAY FOR PAZ004>006- 010-011. && $$ SYNOPSIS...LACORTE NEAR TERM...LACORTE SHORT TERM...LACORTE LONG TERM...LACORTE AVIATION...MARTIN pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 1011 PM CDT MON APR 16 2007 .UPDATE... NO UPDATES TO GOING FORECAST. TEMPERATURES ARE DOING WELL. SKIES ARE CLEAR AND WIND IS DIMINISHING. && .PREV DISCUSSION... .SHORT TERM...TONIGHT THROUGH 12Z THURSDAY. BIGGEST CHALLENGE IN THE NEAR TERM DEALS WITH PCPN CHANCES THIS EVENING...AND TEMPS THROUGH THE PERIOD. COLD FRONT HAS NOW EXITED ALL CWA...WITH REPORTING STATIONS SHOWING NW WINDS. BAND OF PCPN CONTS TO NARROW WITH TIME...WITH BEST REFLECTIVITIES NOW SHOWING UP IN ND. SAT PIX ALSO SHOW CLOUD SHIELD IS BEGINNING TO THIN SOMEWHAT. LATEST ITERATION OF THE RUC SHOWS CWA REMAINING DRY THROUGH 06Z WHICH IS IN AGREEMENT WITH THE HI-RES NAM. HAVE OPTED TO PULL ANY MENTION OF PCPN OUT OF FORECAST THROUGH THE EVENING. SFC HIGH SETTLES INTO NORTHERN PLAINS THROUGH 00Z WEDNESDAY...WITH LIGHT WINDS AND MO CLEAR SKIES. UPPER RIDGE PASSES OVER CWA KEEPING WEAK WAVES AT BAY...HELPING TO BOLSTER MOCLEAR SKIES FORECAST. 85H TEMPS REMAIN THE SAME AS TO WHAT WAS EXPERIENCED TODAY...TO HIGHS TUESDAY HAVE BEEN NUDGED UP A BIT...SIMILAR TO TODAYS. FOR WEDNESDAY...A RETURN TO A WAA PATTERN AS HIGH SLIDES EAST UPPER TROF DIGS TO THE WEST. WITH GULF WIDE OPEN...DID UP DWPTS CONSIDERABLY FOR WEDNESDAY AFTERNOON AND EVENING AS SOUTH/SOUTHEAST WINDS BRING MORE MOISTURE. HIGHS SHOULD ALSO CLIMB A FEW MORE DEGREES. BY 00Z THURSDAY THERE IS AN INCREASE IN CAPE ACROSS OUR FAR WESTERN COUNTIES...AND GIVEN 850MB JET 35+ KTS...SAW NO REASON TO REMOVE MENTION OF SHOWERS OR THUNDERSTORMS ACROSS THE WESTERN COUNTIES WEDNESDAY NIGHT. .LONG TERM...THURSDAY THROUGH MONDAY EXTENDED MODEL SOLUTIONS ARE IN A FAIR AGREEMENT WITH AN ACTIVE WEATHER PATTERN ACROSS THE REGION. THE FIRST SHORT WAVE WILL SWING THROUGH THE AREA THURSDAY THROUGH FRIDAY MORNING...AND EXIT EXTREME EASTERN SOUTH DAKOTA LATE FRIDAY AFTERNOON. ADDED THE MENTION OF THUNDER ACROSS THE AREA AS MID LEVEL TEMPERATURE LAPSE RATES RANGE IN THE SIX TO SEVEN DEGREE RANGE. THERE IS ALSO SOME UNSTABLE CAPE...MAINLY IN THE WEST. GOOD HELICITY VALUES...STRONG LLJ OF AT LEAST 30KTS WITH WAA COULD MAKE FOR INTERESTING WEATHER DAY. THERE WILL BE A SHORT BREAK IN THE ACTION FRIDAY NIGHT...BEFORE ANOTHER SYSTEM BEGINS FOR CHANCES OF THUNDERSTORMS ON SATURDAY. MID LEVEL LAPSE RATES ARE IN THE RANGE OF SEVEN TO EIGHT DEGREES...0-3 KM MOST UNSTABLE CAPE OF 300J IN NORTHERN SD...TO OVER 1000J IN SOUTHERN SD. THIS AREA WILL BE UNDER A THERMAL RIDGED WITH STRONG SOUTHERLY WINDS...WILL ALLOW FOR TEMPERATURE TO REACH 70S IN MOST LOCATIONS. PLENTY OF MOISTURE TO WORK WITH AS DEWPOINTS WILL BE NEAR 50 IN SOUTHERN SD. AGAIN...ALL THIS COULD MAKE FOR AN INTERESTING WEATHER DAY. THIS SYSTEM WILL BE SLOW TO EXIT THE REGION...SO KEEP A CHANCE FOR RAIN SHOWERS THROUGH MONDAY. CCA WRAPS AROUND THE BACK SIDE OF THE LOW SUNDAY NIGHT INTO MONDAY...WITH 850MB TEMPERATES AROUND TWO TO THREE DEGREES ABOVE ZERO. MONDAYS HIGHS ARE THREE TO SIX DEGREES BELOW NORMAL. && .AVIATION... COLD FRONT IS THROUGH THE AREA. SHOWERS HAVE ENDED AND CONDITIONS ARE VFR. THIS WILL PREVAIL THROUGH THE NIGHT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...KEEFE SHORT TERM...HINTZ LONG TERM...DOERING AVIATION...KEEFE sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 321 PM CDT MON APR 16 2007 .SHORT TERM...TONIGHT THROUGH 12Z THURSDAY. BIGGEST CHALLENGE IN THE NEAR TERM DEALS WITH PCPN CHANCES THIS EVENING...AND TEMPS THROUGH THE PERIOD. COLD FRONT HAS NOW EXITED ALL CWA...WITH REPORTING STATIONS SHOWING NW WINDS. BAND OF PCPN CONTS TO NARROW WITH TIME...WITH BEST REFLECTIVITIES NOW SHOWING UP IN ND. SAT PIX ALSO SHOW CLOUD SHIELD IS BEGINNING TO THIN SOMEWHAT. LATEST ITERATION OF THE RUC SHOWS CWA REMAINING DRY THROUGH 06Z WHICH IS IN AGREEMENT WITH THE HI-RES NAM. HAVE OPTED TO PULL ANY MENTION OF PCPN OUT OF FORECAST THROUGH THE EVENING. SFC HIGH SETTLES INTO NORTHERN PLAINS THROUGH 00Z WEDNESDAY...WITH LIGHT WINDS AND MO CLEAR SKIES. UPPER RIDGE PASSES OVER CWA KEEPING WEAK WAVES AT BAY...HELPING TO BOLSTER MOCLEAR SKIES FORECAST. 85H TEMPS REMAIN THE SAME AS TO WHAT WAS EXPERIENCED TODAY...TO HIGHS TUESDAY HAVE BEEN NUDGED UP A BIT...SIMILAR TO TODAYS. FOR WEDNESDAY...A RETURN TO A WAA PATTERN AS HIGH SLIDES EAST UPPER TROF DIGS TO THE WEST. WITH GULF WIDE OPEN...DID UP DWPTS CONSIDERABLY FOR WEDNESDAY AFTERNOON AND EVENING AS SOUTH/SOUTHEAST WINDS BRING MORE MOISTURE. HIGHS SHOULD ALSO CLIMB A FEW MORE DEGREES. BY 00Z THURSDAY THERE IS AN INCREASE IN CAPE ACROSS OUR FAR WESTERN COUNTIES...AND GIVEN 850MB JET 35+ KTS...SAW NO REASON TO REMOVE MENTION OF SHOWERS OR THUNDERSTORMS ACROSS THE WESTERN COUNTIES WEDNESDAY NIGHT. .LONG TERM...THURSDAY THROUGH MONDAY EXTENDED MODEL SOLUTIONS ARE IN A FAIR AGREEMENT WITH AN ACTIVE WEATHER PATTERN ACROSS THE REGION. THE FIRST SHORT WAVE WILL SWING THROUGH THE AREA THURSDAY THROUGH FRIDAY MORNING...AND EXIT EXTREME EASTERN SOUTH DAKOTA LATE FRIDAY AFTERNOON. ADDED THE MENTION OF THUNDER ACROSS THE AREA AS MID LEVEL TEMPERATURE LAPSE RATES RANGE IN THE SIX TO SEVEN DEGREE RANGE. THERE IS ALSO SOME UNSTABLE CAPE...MAINLY IN THE WEST. GOOD HELICITY VALUES...STRONG LLJ OF AT LEAST 30KTS WITH WAA COULD MAKE FOR INTERESTING WEATHER DAY. THERE WILL BE A SHORT BREAK IN THE ACTION FRIDAY NIGHT...BEFORE ANOTHER SYSTEM BEGINS FOR CHANCES OF THUNDERSTORMS ON SATURDAY. MID LEVEL LAPSE RATES ARE IN THE RANGE OF SEVEN TO EIGHT DEGREES...0-3 KM MOST UNSTABLE CAPE OF 300J IN NORTHERN SD...TO OVER 1000J IN SOUTHERN SD. THIS AREA WILL BE UNDER A THERMAL RIDGED WITH STRONG SOUTHERLY WINDS...WILL ALLOW FOR TEMPERATURE TO REACH 70S IN MOST LOCATIONS. PLENTY OF MOISTURE TO WORK WITH AS DEWPOINTS WILL BE NEAR 50 IN SOUTHERN SD. AGAIN...ALL THIS COULD MAKE FOR AN INTERESTING WEATHER DAY. THIS SYSTEM WILL BE SLOW TO EXIT THE REGION...SO KEEP A CHANCE FOR RAIN SHOWERS THROUGH MONDAY. CCA WRAPS AROUND THE BACK SIDE OF THE LOW SUNDAY NIGHT INTO MONDAY...WITH 850MB TEMPERATES AROUND TWO TO THREE DEGREES ABOVE ZERO. MONDAYS HIGHS ARE THREE TO SIX DEGREES BELOW NORMAL. && .AVIATION... SFC COLD FRONT HAS EXITED ENTIRE CWA...WITH NW WINDS TO 30 KTS ACROSS ALL THE AREA. WINDS SHOULD DIMINISH AFT 00Z TO 10 TO 15 KNOTS. SOME SCT-BKN040-050 CIGS ARE POSSIBLE ACROSS KABR AND KATY SITES THROUGH 01Z...BUT SKIES SHOULD CLEAR THEREAFTER. VFR VSBYS EXPECTED ALL NIGHT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...HINTZ LONG TERM...DOERING AVIATION...HINTZ sd AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 905 PM MDT SUN APR 15 2007 .DISCUSSION...02Z SURFACE ANALYSIS SHOWED INITIAL SURFACE TROUGH/COOL FRONT HAS MOVED SOUTH AND EAST OF THE BLACK HILLS. SECONDARY PUSH OF COLDER AIR WILL WAIT UNTIL UPPER TROUGH MOVING ACROSS MT MOVES INTO ND TOWARD MORNING. 00Z KUNR/KRIW SOUNDINGS TELL DRY STORY. ALTHOUGH...AS COOLER AIR WORKS INTO THE AREA T/TD PROFILES WILL CONVERGE. GIVEN SLOWER MOVEMENT OF SYSTEM...HAVE OPTED TO DROP POPS THIS EVENING AND SHAVE POPS OVERNIGHT. THIS IN LINE WITH 00Z RUC/NAM GUIDANCE. UPDATE SOON. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ HELGESON sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 921 PM CDT MON APR 16 2007 .UPDATE...00Z CRP/BRO/DRT SOUNDINGS SHOWS VERY STRONG CAPPING INVERSIONS IN PLACE. CHANCE FOR ANYTHING ELEVATED TONIGHT QUICKLY DIMINISHING...AS BOTH SATELLITE AND RUC ANALYSIS COMBINED WITH MODEL PROGS SHOW LEAD UPR LVL SHORTWAVE ALREADY EAST OF THE RIO GRANDE. THEREFORE...EXPECT WEAK NVA TO DEVELOP OVER THE AREA BEHIND THE SHORTWAVE...AFTER MIDNIGHT. WOULD ONLY EXPECT SOME ISOLATED WEAK STREAMER SHOWERS...BENEATH THE CAP...OVER THE GULF AND NE CWA OVERNIGHT. WON`T MESS TOO MUCH WITH POPS DURING THE DAY ON TUESDAY...JUST SOME MINOR TWEAKS. DID LOWER TONIGHT`S LOWS A COUPLE OF DEGS ACROSS PORTIONS OF THE AREA...BASED UPON CURRENT READINGS ALREADY APPROACHING FORECASTED LOWS. WINDS HAVE BEEN TRICKY THIS EVENING...AND HAVE DROPPED CONSIDERABLY ACROSS THE COASTAL BEND AND NRN BAYS. DO EXPECT THEM TO INCREASE BACK INTO SCEC RANGE OVER THE BAYS AND POSSIBLE SCA CONDITIONS OVER THE GULF AS LLJ CONTINUES TO STRENGTHEN. && .AVIATION...VFR CONDITIONS THIS EVENING ARE EXPECTED TO LOWER TO MVFR BETWEEN 06-09Z AND REMAIN INTO TUESDAY AFTERNOON. AN UPPER LEVEL DISTURBANCE OVER THE SW U.S. TONIGHT WILL MOVE EASTWARD ACROSS NORTH TEXAS ON TUESDAY. THE ATMOSPHERE WILL REMAIN RELATIVELY STABLE AS THIS UPPER LEVEL SYSTEM MOVES BY TO THE NORTH. HOWEVER...GIVEN INCREASING DEEP LAYER MOISTURE COUPLED WITH SOME AFTERNOON HEATING...EXPECT SMALL CHANCES FOR SHOWERS AND ISOLATED T-STORMS... MAINLY OVER THE NE REGION (INCLUDING VCT). A DRY-LINE FEATURE IS EXPECTED TO MOVE FROM WEST TO EAST ACROSS THE REGION AS THE UPPER DISTURBANCE MOVES EAST OF THE AREA...WHICH WILL IMPROVE CIGS OVER THE WEST (INCLUDING LRD)BEFORE NOON TUESDAY...AND POSSIBLY TO ALI/CRP BY LATE AFTERNOON. && .PREV DISCUSSION... /ISSUED 220 PM CDT MON APR 16 2007/ SHORT-TERM (TONIGHT THROUGH TUESDAY NIGHT)...700HPA SHORTWAVE ADVANCES ACROSS THE REGION OVERNIGHT/TUESDAY MORNING. CAPPING INVERSION REMAINS QUITE STRONG BUT SOME MID-LEVEL MOISTURE/STEEPER LAPSE RATES AND NEARNESS OF 500/250HPA JET STREAKS TENUOUSLY SUPPORTS SLIGHT CHANCE/LOW-END CHANCE POPS FOR ELEVATED CONVECTION ACROSS THE NORTHEAST CWA. WILL INDICATE SLIGHT CHANCE POPS SOUTH OF THIS AREA AND AS FAR WEST AS THE COASTAL PLAINS TUESDAY AS LOW-LEVEL MOISTURE/FORCING PRECEDING THE DRYLINE APPEARS SUFFICIENT FOR ISOLATED SHOWERS BENEATH A RISING CAPPING INVERSION. THE DRYLINE IS EXPECTED TO REACH AS FAR EAST AS THE COASTAL PLAINS BY LATE TUESDAY AFTERNOON THEN DRIFT ACROSS THE REMAINDER OF THE AREA TUESDAY NIGHT. BOUNDARY LAYER MOISTURE WILL REMAIN ADEQUATELY HIGH AS DRIER AIR ALOFT ADVECTS IN AND SIGNIFICANT LOW-LEVEL STABILIZATION OCCURS. HAVE THEREFORE INDICATED AREAS OF FOG TUESDAY NIGHT ACROSS THE COASTAL BEND/VICTORIA CROSSROADS REGION. BREEZY/WINDY CONDITIONS WITHIN A WELL-MIXED BOUNDARY LAYER WILL PERSIST INTO EARLY THIS EVENING. ONLY MINOR TWEAKS TO THE PREVIOUS TEMPERATURE GRIDS. AVIATION...SOUTHEAST WIND GUSTS BETWEEN 25-30 KNOTS WILL END BY 02Z. AT THAT TIME...VFR CIGS WILL DEVELOP THEN LOWER TO HIGH-END MVFR CIGS BY 06Z AND PERSIST UNTIL 16Z. AFTER 16Z VFR CIGS WILL PREVAIL WITH CLEARING ACROSS THE WESTERN RIO GRANDE PLAINS. MOSTLY ISOLATED CONVECTION IS POSSIBLE AFTER 09Z TONIGHT THROUGH TUESDAY WITH MARGINAL SCATTERED CONVECTION NORTH OF A HOLIDAY BEACH TO CHARCO LINE. MARINE...WILL MAINTAIN MARGINAL SCA CONDITIONS FOR THE SOUTHERN BAYS UNTIL 01Z IN WELL MIXED BOUNDARY LAYER AND TIGHT PRESSURE GRADIENT. SCA CONDITIONS WILL DEVELOP BY 03Z ACROSS THE NEARSHORE/OFFSHORE WATERS AND PERSIST INTO TUESDAY MORNING AS THE LOW-LEVEL JET INCREASES. FIRE WEATHER...ALTHOUGH THE DRYLINE EDGES INTO THE COASTAL PLAINS BY LATE TUESDAY AFTERNOON...SUFFICIENT DEEP LAYERED MIXING WITH WIND GUSTS TO 25 KNOTS WILL BE CONFINED TO POINTS WEST OF A ENCINAL TO LAREDO TO RIO BRAVO LINE. SINCE THIS BARELY AFFECTS WEBB COUNTY AND UNCERTAINTY STILL EXISTS...WILL FOREGO A FIRE WEATHER WATCH/RED FLAG WARNING. LONG-TERM (WEDNESDAY THROUGH MONDAY)...WEAK PACIFIC FRONT IS PROGGED TO PUSH OFF THE COAST BY EARLY WEDNESDAY WITH A BRIEF EPISODE OF MOD/STRONG OFFSHORE WINDS AND LOWER HUMIDITIES. WINDS WILL BE BORDERLINE SCA OVER THE COASTAL WATERS UNTIL MID WED AFTN. DURING THE DAY WEDNESDAY...UPPER LOW PUSHES EAST INTO THE SE U.S AS UPSTREAM UPPER RIDGE AMPLIFIES INTO AND THEN INTO THE LONE STAR STATE. NAM MORE AGGRESSIVE WITH AMOUNT OF CAA ASSOCIATED WITH PACIFIC FRONT THAN GFS. WILL TREND A FEW DEGREES BELOW THE WARMER GFS WITH H8 TEMPS NOT CHANGING VERY MUCH ON EITHER MODEL. SURFACE RIDGE AXIS REMAINS ACROSS THE REGION WEDNESDAY NIGHT WITH DRY/SUBSIDENT CONDITIONS. WEAK SFC HIGH REMAINS OVER OR TO THE EAST OF SOUTH TX THU/FRI WITH DRY WEATHER/SEASONABLE TEMPS EXPECTED. A SLOW INCREASE IN MOISTURE WILL BEGIN THIS WEEKEND AS ONSHORE FLOW RETURNS WITH APPROACH OF ANOTHER BUT STRONGER LONG WAVE TROF MOVING ACROSS THE DESERT SOUTHWEST AND AS THE MID-LEVEL RIDGE AXIS MOVES EAST AND ALLOWING A W/SW FLOW ALOFT WITH WEAK EMBEDDED DISTURBANCES TO PREVAIL AT WEEK`S END THROUGH THE BEGINNING OF NEXT WEEK. BREEZY/WINDY INLAND AND SCEC/LOW-END SCA CONDITIONS SLOWLY BECOME ESTABLISHED AS THE PRESSURE GRADIENT/LOW-LEVEL JET INCREASE. BOUTS OF MID/HIGH CLOUDINESS IS EXPECTED FRIDAY AND SATURDAY WITH GRADUALLY INCREASING LOWER TROPOSPHERIC MOISTURE. AT THE BEGINNING OF NEXT WEEK...THERE IS A STRONGER VORT LOBE THAT IS PROGGED TO TREK ACROSS NRN MEXICO INTO OUR REGION. WILL KEEP IN MINIMAL LOW END POPS GIVEN LOW LEVEL MOISTURE INCREASE AND POSSIBLE EMBEDDED DISTURBANCE BUT WITH THE LACK OF DEFINED FORCING IN CONCERT WITH A STRONG CAP WINDY AND DRY CONDITIONS MOST LIKELY AT THE BEGINNING OF NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 64 80 56 83 62 / 10 10 10 0 0 VICTORIA 60 78 55 80 55 / 10 40 10 0 0 LAREDO 67 90 61 90 64 / 10 10 0 0 0 ALICE 63 84 55 84 58 / 10 10 10 0 0 ROCKPORT 64 77 58 80 62 / 10 10 10 0 0 COTULLA 60 86 51 87 57 / 10 10 0 0 0 KINGSVILLE 64 83 55 84 59 / 10 10 10 0 0 NAVY CORPUS 66 77 61 81 63 / 10 10 10 0 0 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 10 AM CDT TUESDAY FOR THE FOLLOWING ZONES: COASTAL WATERS BAFFIN BAY TO PORT ARANSAS OUT 20 NM...COASTAL WATERS PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM. SMALL CRAFT ADVISORY UNTIL 12 PM CDT TUESDAY FOR THE FOLLOWING ZONES: WATERS BAFFIN BAY TO PORT ARANSAS 20 TO 60 NM... WATERS PORT ARANSAS TO MATAGORDA SHIP CHANNEL 20 TO 60 NM. && $$ JR/76...SHORT TERM RM/33...AVIATION tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 1158 AM CDT SUN APR 15 2007 .AVIATION...VFR FOR THE NEXT 12 HOURS. MAYBE SOME PATCHY FOG AROUND SUNRISE BUT DID NOT MENTION IN TAFS. LOW LEVEL MOISTURE BEGINS TO INCREASE MONDAY MORNING AND AM EXPECTING A FEW MORE CLOUDS. CIRRUS SHIELD ALSO EXPECTED TO INCREASE AROUND 12Z. 43 .DISCUSSION...MSAS SURFACE ANALYSIS INDICATED HIGH PRESSURE CENTERED ACROSS CENTRAL AND EAST TEXAS THIS MORNING. RUC80 500MB HEIGHT ANALYSIS INDICATED A RIDGE BUILDING INTO THE CENTRAL UNITED STATES AS THE TROUGH OVER THE EASTERN U.S. MOVES EASTWARD. IN ADDITION...ANOTHER TROUGH/LOW WAS MOVING EASTWARD ACROSS SOUTHERN CALIFORNIA. RUC80 1000-500MB WIND STREAMLINE ANALYSIS INDICATED NORTHWEST FLOW ACROSS EAST TX AND THIS WILL PROVIDE SUBSIDENCE ACROSS THE CWA THIS AFTERNOON. LIGHT AND VARIABLE WINDS IN COMBINATION WITH CLEAR SKIES WILL ALLOW TEMPERATURES TO REBOUND INTO THE UPPER 60S TO LOWER 70S TODAY. NO CHANGES EXPECTED TO THE CURRENT FORECAST. A REALLY NICE DAY TODAY...ENJOY! 32 && .PREV DISCUSSION... /ISSUED 319 AM CDT SUN APR 15 2007/ COOL/DRY AIRMASS SETTLING INTO SE TX EARLY THIS MORNING AS SFC HIGH MOVES INTO THE REGION. CLOUDS HAVE CLEARED OUT OF THE CWA AND SKIES WILL REMAIN CLEAR TODAY. DESPITE THE SUNSHINE...TEMPS WILL REMAIN COOL TODAY AS 850 MB TEMPS WARM ONLY SLIGHTLY THIS AFTN. HIGH CLOUDINESS WILL BEGIN SPREADING ACROSS SE TX BY EARLY MONDAY. SFC HIGH WILL PUSH EAST OF THE AREA WITH ONSHORE FLOW RETURNING BY LATE MONDAY. MODELS SHOW THE UPPER LOW CURRENTLY OVER SOUTHERN CALIFORNIA CROSSING THE STATE ON TUESDAY. PREFER SLOWER SOLUTION SHOWN BY THE MAJORITY OF THE MODELS WHICH ARE ABOUT 6-9 HOURS SLOWER THAN THE GFS. LOW LEVEL JET OF 40 KTS WILL DEVELOP OVER THE AREA BEGINNING EARLY TUESDAY AS UPPER LOW APPROACHES. JET DYNAMICS LOOK IMPRESSIVE WITH THIS SYSTEM WITH MODELS SHOWING 120 KT JET MAX AT 300 MB REACHING SE TX TUE AFTN. IN ADDITION...DRYLINE/FRONT WILL ACT AS A FOCUS FOR CONVECTIVE DEVELOPMENT TUE AFTN/EVENING AS IT PUSHES INTO SE TX. WARM FRONT WILL LIKELY SET UP OVER SE TX FOR THIS EVENT WITH FAVORABLE LOW LEVEL SHEAR PROFILE FOR SEVERE WEATHER. HOWEVER...MODELS SHOW ONLY MODEST INSTABILITY DEVELOPING TUESDAY DUE TO EXTENSIVE CLOUD COVER IN PLACE. IN ADDITION...MOISTURE RETURN FROM THE GULF LIMITED BY SOMEWHAT CURRENT COLD SURGE. MODEL FORECAST SOUNDINGS SHOW CAPES LESS THAN 1000 J/KG AND LIS AROUND 0 FOR THE DURATION OF THE EVENT. THESE FACTORS SUPPORT ONLY A LOW THREAT OF SEVERE STORMS TUESDAY MAINLY TOWARD THE COAST. UPPER LOW LIFTS EAST OF THE AREA TUE NIGHT WITH SFC FRONT/DRYLINE PUSHING OFF THE COAST. WEDNESDAY/THURSDAY WILL SEE LOTS OF SUNSHINE AND LOWER HUMIDITIES AS WEAK SFC HIGH SETTLES OVER THE AREA. ONSHORE FLOW DEVELOPS LATE THURSDAY BUT ONLY A SLOW INCREASE IN MOISTURE WILL OCCUR THROUGH THE WEEKEND WITH WEAK UPPER RIDGING IN PLACE. HAVE KEPT FORECAST PRECIP FREE GOING INTO THE WEEKEND WITH NEAR NORMAL TEMPS. AVIATION... LOW CLOUDS HAS MOVE TO SOUTHEAST OF CWFA EARLY THIS MORNING. SURFACE WINDS ACROSS INLAND SITES HAS SIGNIFICANTLY DECREASED THE LAST FEW HOURS. GLS SHOULD SEE DECREASING NORTH WINDS MID TO LATE MORNING. OTHERWISE VFR ALL SITES FOR THIS FORECAST PERIOD. MARINE... PRESSURE GRADIENT RAPIDLY RELAXING THIS MORNING WITH HIGH PRESSURE SETTLING OVER THE REGION. WAVE HEIGHTS 20-60 NM REGION REMAINING ON THE HIGH SIDE DURING MORNING HOURS. BAYS ALREADY SEEING WINDS DECREASING SIGNIFICANTLY. WE SHALL CONTINUE WITH SCA FOR 0-20 NM REGION THROUGH MID MORNING AND THROUGH MID DAY FOR 20-60 NM REGION. LIGHT ONSHORE FLOW SHOULD BE EVIDENT BY TONIGHT WITH HIGH PRESSURE CENTER MOVING TO THE WESTERN GULF. ONSHORE FLOW STRENGTHENING TOMORROW WITH COASTAL WATERS WINDS REACHING SCA CRITERIA MONDAY NIGHT 20-60 NM REGION. NEXT FRONT SHOULD CROSS COASTAL WATERS TUESDAY NIGHT USHERING A BRIEF STRONG OFFSHORE FLOW. && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 72 45 75 55 75 / 0 0 0 20 50 HOUSTON (IAH) 71 46 75 55 75 / 0 0 0 20 40 GALVESTON (GLS) 69 55 71 63 74 / 0 0 0 20 40 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$ DISCUSSION...32 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 1014 AM CDT SUN APR 15 2007 .UPDATE...BEAUTIFUL DAY ACROSS SOUTH TEXAS WITH HIGH PRESSURE RIDGE OVER THE REGION. THIS RIDGE AXIS WILL MOVE INTO THE NORTHWEST GULF OF MEXICO THIS AFTERNOON WITH LIGHT EAST-SOUTHEAST WINDS DEVELOPING. TEMPERATURES ARE IN THE UPPER 50S OVER THE GULF WATERS AND WITH EAST WINDS EXPECTED THIS AFTERNOON...TEMPS MAY STRUGGLE TO REACH FORECAST VALUES ACCORDING TO LATEST NAM/RUC FORECAST SOUNDINGS. LOWERED THE MAX TEMPS FOR TODAY GENERALLY 2 DEGREES MOST AREAS. NO OTHER CHANGES. && .MARINE...WILL MAINTAIN SCA FOR THE OFFSHORE WATERS UNTIL 18Z AS SEAS CONTINUE AROUND 7 FEET AT BUOY 19. WINDS AND SEAS WILL CONTINUE TO SUBSIDE THIS AFTERNOON AS RIDGE AXIS MOVES IN. && .PREV DISCUSSION... /ISSUED 334 AM CDT SUN APR 15 2007/ SHORT-TERM (TODAY THROUGH MONDAY)...CHAMBER OF COMMERCE WEATHER IS ON TAP FOR TODAY AS S/WV RIDGING ALOFT MOVES OVER THE REGION AND SURFACE HIGH PRESSURE SETTLES INTO SOUTH TEXAS. FOLLOWED THE WARMEST FWC GUIDANCE FOR HIGHS TODAY GIVEN UNINHIBITED INSOLATION. IN ADDITION...BOUNDARY LAYER FLOW IS EXPECTED TO WEAKEN AND BECOME ONSHORE LATER TODAY. FOR TONIGHT...THINK THE GFS IS TOO QUICK WITH MOISTURE RETURN IN RESPONSE TO TH MID/UPR LOW DIGGING INTO THE DESERT SOUTHWEST. ALSO THINK THE NAM IS TOO SLOW WITH MOISTURE RETURN. AS A RESULT...WENT WITH A BLEND OF MAV/MET GUIDANCE FOR LOWS TONIGHT. MOISTURE RETURN WILL INCREASE MONDAY AS THE MID/UPR LOW PUSHES INTO NEW MEXICO AND PRESSURE GRADIENT INCREASES OVER SOUTH TEXAS. BREEZY/WINDY CONDITIONS ARE EXPECTED TO DEVELOP OVER MOST OF SOUTH TEXAS...ESPECIALLY OVER THE SOUTHERN COASTAL PLAINS. INCREASING MOISTURE WILL ALSO INCREASE THE CLOUD COVER MONDAY AND SHOULD OFFSET THE INCREASING WAA. AS A RESULT...THINK TEMPS MONDAY WILL BE SIMILAR TO TODAY`S READINGS. MARINE...SCA WINDS OVER THE GULF WILL GRADUALLY DIMINISH THIS MORNING AS HIGH PRESSURE MOVES INTO SOUTH TEXAS. EXTENDED THE SCA UNTIL 18Z (1 PM CDT) FOR THE COASTAL WATERS 20 TO 60 NM OFFSHORE FROM BAFFIN BAY TO PORT ARANSAS DUE TO SEAS RUNNING AROUND 7 FEET. AVIATION...VFR CONDITIONS WILL PREVAIL OVER ALL SOUTH TEXAS TERMINAL AERODROME SITES THROUGH SUNDAY NIGHT. LONG-TERM (MONDAY NIGHT THROUGH SATURDAY)...THINGS REMAIN PRETTY MUCH STATUS-QUO W.R.T. TIMING OF UPPER SYSTEMS...AS GFS IS FASTER AND NAM IS SLOWER WITH TROUGH ACROSS TX ON TUESDAY. CONTINUED TO KIND OF SPLIT THE DIFFERENCE...WITH ALL OF THE PRECIP (IF ANY) MOVING OUT OF THE AREA BY 21Z TUESDAY. GFS AND NAM CONTINUE TO SHOW GENERALLY A STABLE AIRMASS FOR SURFACE FORCING...BUT COULD BE ENOUGH LARGE SCALE LIFT VIA CVA OR JET DYNAMICS FOR ELEVATED STORMS...THUS MAINTAINED THUNDER IN FORECAST WITH VERY MINOR ADJUSTMENTS TO PREVIOUS POP FORECAST. NO RAIN AFTER TUESDAY AFTERNOON...AS UPPER RIDGE BUILDS IN WEDNESDAY...MOVES EAST AND WEAKENS THURSDAY...THEN WSW FLOW AFTER THAT WITH SURFACE TROUGH DEVELOPING OVER WEST TEXAS...BRINGING WINDS...MOISTURE AND TEMPERATURES UP. OVERALL... PREVIOUS FORECAST WAS ADJUSTED JUST LITTLE AS OVERALL FORECAST TRENDS REMAIN THE SAME. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 73 54 77 67 86 / 0 0 10 10 20 VICTORIA 73 50 76 63 80 / 0 0 10 20 40 LAREDO 79 58 81 69 95 / 0 0 10 10 10 ALICE 76 51 78 66 90 / 0 0 10 10 20 ROCKPORT 72 57 75 67 81 / 0 0 10 10 30 COTULLA 76 52 77 62 90 / 0 0 10 20 10 KINGSVILLE 76 53 78 66 89 / 0 0 10 10 20 NAVY CORPUS 71 59 74 69 82 / 0 0 10 10 20 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR THE FOLLOWING ZONES: WATERS BAFFIN BAY TO PORT ARANSAS 20 TO 60 NM...WATERS PORT ARANSAS TO MATAGORDA SHIP CHANNEL 20 TO 60 NM. && $$ TMT/89...SHORT TERM tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 959 AM CDT SUN APR 15 2007 .DISCUSSION...MSAS SURFACE ANALYSIS INDICATED HIGH PRESSURE CENTERED ACROSS CENTRAL AND EAST TEXAS THIS MORNING. RUC80 500MB HEIGHT ANALYSIS INDICATED A RIDGE BUILDING INTO THE CENTRAL UNITED STATES AS THE TROUGH OVER THE EASTERN U.S. MOVES EASTWARD. IN ADDITION...ANOTHER TROUGH/LOW WAS MOVING EASTWARD ACROSS SOUTHERN CALIFORNIA. RUC80 1000-500MB WIND STREAMLINE ANALYSIS INDICATED NORTHWEST FLOW ACROSS EAST TX AND THIS WILL PROVIDE SUBSIDENCE ACROSS THE CWA THIS AFTERNOON. LIGHT AND VARIABLE WINDS IN COMBINATION WITH CLEAR SKIES WILL ALLOW TEMPERATURES TO REBOUND INTO THE UPPER 60S TO LOWER 70S TODAY. NO CHANGES EXPECTED TO THE CURRENT FORECAST. A REALLY NICE DAY TODAY...ENJOY! 32 && .PREV DISCUSSION... /ISSUED 319 AM CDT SUN APR 15 2007/ COOL/DRY AIRMASS SETTLING INTO SE TX EARLY THIS MORNING AS SFC HIGH MOVES INTO THE REGION. CLOUDS HAVE CLEARED OUT OF THE CWA AND SKIES WILL REMAIN CLEAR TODAY. DESPITE THE SUNSHINE...TEMPS WILL REMAIN COOL TODAY AS 850 MB TEMPS WARM ONLY SLIGHTLY THIS AFTN. HIGH CLOUDINESS WILL BEGIN SPREADING ACROSS SE TX BY EARLY MONDAY. SFC HIGH WILL PUSH EAST OF THE AREA WITH ONSHORE FLOW RETURNING BY LATE MONDAY. MODELS SHOW THE UPPER LOW CURRENTLY OVER SOUTHERN CALIFORNIA CROSSING THE STATE ON TUESDAY. PREFER SLOWER SOLUTION SHOWN BY THE MAJORITY OF THE MODELS WHICH ARE ABOUT 6-9 HOURS SLOWER THAN THE GFS. LOW LEVEL JET OF 40 KTS WILL DEVELOP OVER THE AREA BEGINNING EARLY TUESDAY AS UPPER LOW APPROACHES. JET DYNAMICS LOOK IMPRESSIVE WITH THIS SYSTEM WITH MODELS SHOWING 120 KT JET MAX AT 300 MB REACHING SE TX TUE AFTN. IN ADDITION...DRYLINE/FRONT WILL ACT AS A FOCUS FOR CONVECTIVE DEVELOPMENT TUE AFTN/EVENING AS IT PUSHES INTO SE TX. WARM FRONT WILL LIKELY SET UP OVER SE TX FOR THIS EVENT WITH FAVORABLE LOW LEVEL SHEAR PROFILE FOR SEVERE WEATHER. HOWEVER...MODELS SHOW ONLY MODEST INSTABILITY DEVELOPING TUESDAY DUE TO EXTENSIVE CLOUD COVER IN PLACE. IN ADDITION...MOISTURE RETURN FROM THE GULF LIMITED BY SOMEWHAT CURRENT COLD SURGE. MODEL FORECAST SOUNDINGS SHOW CAPES LESS THAN 1000 J/KG AND LIS AROUND 0 FOR THE DURATION OF THE EVENT. THESE FACTORS SUPPORT ONLY A LOW THREAT OF SEVERE STORMS TUESDAY MAINLY TOWARD THE COAST. UPPER LOW LIFTS EAST OF THE AREA TUE NIGHT WITH SFC FRONT/DRYLINE PUSHING OFF THE COAST. WEDNESDAY/THURSDAY WILL SEE LOTS OF SUNSHINE AND LOWER HUMIDITIES AS WEAK SFC HIGH SETTLES OVER THE AREA. ONSHORE FLOW DEVELOPS LATE THURSDAY BUT ONLY A SLOW INCREASE IN MOISTURE WILL OCCUR THROUGH THE WEEKEND WITH WEAK UPPER RIDGING IN PLACE. HAVE KEPT FORECAST PRECIP FREE GOING INTO THE WEEKEND WITH NEAR NORMAL TEMPS. AVIATION... LOW CLOUDS HAS MOVE TO SOUTHEAST OF CWFA EARLY THIS MORNING. SURFACE WINDS ACROSS INLAND SITES HAS SIGNIFICANTLY DECREASED THE LAST FEW HOURS. GLS SHOULD SEE DECREASING NORTH WINDS MID TO LATE MORNING. OTHERWISE VFR ALL SITES FOR THIS FORECAST PERIOD. MARINE... PRESSURE GRADIENT RAPIDLY RELAXING THIS MORNING WITH HIGH PRESSURE SETTLING OVER THE REGION. WAVE HEIGHTS 20-60 NM REGION REMAINING ON THE HIGH SIDE DURING MORNING HOURS. BAYS ALREADY SEEING WINDS DECREASING SIGNIFICANTLY. WE SHALL CONTINUE WITH SCA FOR 0-20 NM REGION THROUGH MID MORNING AND THROUGH MID DAY FOR 20-60 NM REGION. LIGHT ONSHORE FLOW SHOULD BE EVIDENT BY TONIGHT WITH HIGH PRESSURE CENTER MOVING TO THE WESTERN GULF. ONSHORE FLOW STRENGTHENING TOMORROW WITH COASTAL WATERS WINDS REACHING SCA CRITERIA MONDAY NIGHT 20-60 NM REGION. NEXT FRONT SHOULD CROSS COASTAL WATERS TUESDAY NIGHT USHERING A BRIEF STRONG OFFSHORE FLOW. && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 72 45 75 55 75 / 0 0 0 20 50 HOUSTON (IAH) 71 46 75 55 75 / 0 0 0 20 40 GALVESTON (GLS) 69 55 71 63 74 / 0 0 0 20 40 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$ DISCUSSION...32 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 405 AM CDT MON APR 16 2007 FORECAST FOCUS ON QUIET AND PLEASANT CONDITIONS TODAY...CHANCE OF PRECIP ON TUESDAY...THEN COOLER TEMPS AND CLOUD TRENDS WEDNESDAY. 00Z UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY INDICATING A HIGHLY AMPLIFIED PATTERN OVER THE CONUS WITH TROUGHS OVER THE EAST AND WEST COASTS...WITH MEAN RIDGE POSITIONED OVER THE CENTRAL CONUS. 00Z RAOBS UPSTREAM SHOWING NICE POCKET OF WARM AIR OVER THE PLAINS...WITH 850MB TEMPS AOA 10C FROM KS TO ND. AT THE SFC...08Z MSAS ANALYSIS INDICATED A WEAK RIDGE CENTERED OVER WI...WITH IR IMAGERY EARLY THIS MORNING SHOWING CLEAR SKIES OVER ALL OF WI. TODAY...GFS/NAM/RUC IN GOOD AGREEMENT CO-LOCATING SFC/UPPER RIDGING OVER WI THIS AFTERNOON. COLUMN DRY AND SUBSIDENT...RESULTING IN SUNNY SKIES AND PLEASANT TEMPERATURES. MAVMOS GUIDANCE LOOKED REASONABLE...WITH ONLY CAVEAT THE USUAL COOLING EFFECTS FROM THE LAKE BREEZE...ALTHOUGH 4KM/20KM WRF_ARW MODELS SHOWING IT GENERALLY HOLDING TIGHT ALONG LAKESHORE TIL 20-21Z. OVERALL...SHOULD BE A FINE DAY FOR MID APRIL. TONIGHT...UPPER TROUGH AND ASSOCIATED COLD FRONT TO APPROACH FROM NORTHWEST WITH NAM STILL ABOUT 6 HOURS FASTER THAN GFS. WITH OVERALL BLOCKY UPPER AIR PATTERN...CONTINUE TO PREFER THE SLIGHTLY SLOWER GFS SOLUTION...THUS WILL MAINTAIN DRY FORECAST FOR TONIGHT AND ONLY SHOW INCREASING CLOUDS. TUESDAY/TUESDAY NIGHT...CONTINUE TO FAVOR THE GFS WITH RESPECT TO THE TIMING AND STRENGTH OF THE SHORTWAVE. AS SUCH...BEST UPPER LEVEL FORCING/Q-VECTOR CONVERGENCE EXPECTED TO REMAIN OVER NORTHERN WISCONSIN. GFS INDICATING A PERIOD OF LOW LEVEL FORCING/ISENTROPIC LIFT MOVING ACROSS CWA BETWEEN 15Z-00Z...HOWEVER SATURATION IS GENERALLY CONFINED BELOW 600MB WITH VERY DRY AIR ABOVE 500MB AND ALSO NEAR THE SFC. WITH GULF OF MEXICO ESSENTIALLY CLOSED DOWN...MOISTURE ADVECTION MARGINAL. SLIGHT CHANCE OF SHOWERS LOOKS TO BE THE WAY TO GO FOR NOW...WHICH AGREES WELL WITH SREF GUIDANCE. ANY QPF WITH THIS SYSTEM EXPECTED TO BE VERY LIGHT. SFC COLD FRONT EXPECTED TO DROP SOUTH OF AREA BY TUESDAY NIGHT AS SFC HIGH BUILDS NORTH OF LAKE SUPERIOR. WEDNESDAY...UPPER SHORTWAVE ATTEMPTS TO CLOSE OFF OVER THE OHIO VALLEY ON WEDNESDAY AFTERNOON PRODUCING A DEEP NELY FLOW ALOFT OVER THE GREAT LAKES. MEANWHILE SFC HIGH NORTH OF LAKE SUPERIOR TO REINFORCE A COLD AND MOIST NELY SFC FLOW OVER SRN WI. EXPECTING WIDESPREAD STRATUS TO SPILL INTO ERN WI AS MODEL SOUNDINGS SHOWING PLENTY OF LOW LEVEL SATURATION DUE TO PERSISTENT CAA. COULD ALSO SEE SHOWERS OR DRIZZLE DEVELOP AS MOISTURE ROTATES IN FROM THE EAST...BUT WILL LEAVE OUT FOR NOW. TEMPS WILL ALSO BE SIGNIFICANTLY COOLER...WITH TEMPS STRUGGLING TO GET INTO THE 40S EAST .LONG TERM...THURSDAY THROUGH SUNDAY... LITTLE CHANGE IN THINKING FOR THE EXTENDED PERIOD AS UPPER LEVEL OMEGA BLOCK DEVELOPS OVER THE US. SEVERAL PACIFIC SYSTEM WILL ATTEMPT TO BREAK DOWN THE BLOCK BY THE WEEKEND...HOWEVER PLENTY OF MODEL UNCERTAINTY WITH REGARDS TO THE STRENGTH OF THESE FEATURES. && .AVIATION...VFR CONDITIONS WILL CONTINUE THROUGH TONIGHT. NARROW HIGH PRESSURE RIDGE WILL SETTLE OVR WI DURG THE FCST PERIOD. TOWARD END OF PD...A WEAK LOW PRESSURE SYSTEM AND COLD FRONT NOW OVR THE NRN PLAINS WILL DRIFT EAST INTO WRN WI. THIS LOW PRES AND CDFNT WILL DRIFT ACROSS SRN WI BETWEEN 12Z AND 18Z TUE. && .MKX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ FOWLE/DAVIS wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 325 AM EDT TUE APR 17 2007 .SYNOPSIS... 07Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A 531 DAM LOW OFF THE COAST OF NEW JERSEY ASSOCIATED WITH YESTERDAYS INTENSE NOR`EASTER. TO THE WEST OF THE LOW...AN UPPER RIDGE IS LOCATED OVER EASTERN UPPER MICHIGAN. DRY AIR AND SUBSIDENCE ASSOCIATED WITH THIS RIDGE (SEE 00Z GRB AND APX SOUNDINGS) IS HELPING TO KEEP SKIES CLEAR OVER THE EASTERN HALF OF UPPER MICHIGAN. MORE CLOUDS ALONG WITH SOME LIGHT RAIN IS LOCATED OVER WESTERN LAKE SUPERIOR...WESTERN UPPER MICHIGAN AND NW WISCONSIN PER LATEST IR SATELLITE AND RADAR LOOPS. THIS IS ASSOCIATED WITH MID-LEVEL FRONTOGENESIS AND DPVA FROM A SHRTWV TROUGH WHICH STRETCHES FROM NW ONTARIO INTO EASTERN MN. IT SHOULD BE NOTED THAT THE BAND OF CLOUDS AN SHOWERS CONTINUES TO SHRINK...DUE TO STRONG DRYING COMING IN BEHIND THE SHRTWV (SEE EXTREMELY DRY 00Z BIS SOUNDING) AND THE DRY AIR OVER UPPER MICHIGAN. THE STRONG DRYING AREA IS LOCATED UNDER ANOTHER UPPER RIDGE...WHICH EXTENDS FROM WYOMING NORTHWARD INTO SOUTH CENTRAL CANADA. TO THE WEST OF THIS RIDGE...A LARGE TROUGH CAN BE SEEN MOVING INTO THE WEST COAST...WITH A 110 KT JET PUNCHING INTO NORTHERN CALIFORNIA. AT THE SURFACE...A WEAKENING HIGH PRESSURE RIDGE OF 1015MB COVERS EASTERN UPPER MICHIGAN...A COLD FRONT EXTENDS FROM JAMES BAY INTO WESTERN UPPER MICHIGAN AND A 1022MB HIGH PRESSURE AREA IS BUILDING ALONG THE MANITOBA AND ONTARIO BORDER. 850MB TEMPS COOL DOWN SLIGHTLY BEHIND THE FRONT...WITH 2C READINGS AT INL AND CWPL AND -1C AT CYQD FROM 00Z SOUNDINGS. && .DISCUSSION... MAIN FORECAST CONCERNS ARE LOW CLOUDS AND PCPN POTENTIAL TONIGHT THROUGH THURSDAY. TODAY...SHRTWV TROUGH OVER MINNESOTA IS PROGGED TO CONTINUE PUSHING EAST THIS MORNING...BUT THEN STALL OVER THE CENTRAL PORTION OF UPPER MICHIGAN AS RIDGING BUILDS UP INTO NORTHERN ONTARIO AND CUTS THE TROUGH INTO TWO. WITH THE TROUGH MOVING INTO DRIER AIR AND PLENTY OF DRY AIR IS MOVING IN BEHIND THE TROUGH...WOULD EXPECT THE BAND OF CLOUDS TO SQUEEZE SMALLER. IN FACT...AT LEAST THE WESTERN U.P. SHOULD BECOME SUNNY THIS AFTERNOON AS THE DRIER AIR SEEN ON THE 00Z BISMARCK SOUNDING MOVES IN. REGARDING THE SHOWERS...THESE SHOULD ALSO DIMINISH AS THEY RUN INTO THE DRIER AIR...PERHAPS BARELY EVEN GETTING INTO MARQUETTE COUNTY. PLAN ON HAVING A DRY AFTERNOON FORECAST SINCE IT APPEARS THE RAIN SHOULD HAVE FALLEN APART BY THEN. TEMPERATURES WILL BE COOLER TODAY...PARTICULARLY ALONG LAKE SUPERIOR DUE TO A STRENGTHENING NORTHERLY WIND. THIS INCREASE IN WIND IS A RESULT OF BOTH THE COLD FRONT PASSING THROUGH AND THE HIGH PRESSURE IN MANITOBA STRENGTHENING TO 1027MB AS IT LIFTS INTO NORTHERN ONTARIO. THE SOUTHERN U.P. SHOULD STILL SEE ENOUGH SUN TO COMBINE WITH 850MB TEMPS AROUND 2C TO REACH THE MID OR EVEN UPPER 50S. WILL NOT GO AS HIGH AS MET GUIDANCE...PARTICULARLY FOR IMT...SINCE IT SEEMS A BIT TOO WARM WITH MORE CLOUD COVER EXPECTED THAN YESTERDAY. TONIGHT...A STRONG SHRTWV LOCATED AT THE BASE OF THE TROUGH ENTERING THE PACIFIC NW IS EXPECTED TO MOVE INTO SOUTHERN NEVADA BY 12Z. WARM ADVECTION DOWNSTREAM OF THIS SHRTWV TROUGH WILL CONTINUE TO BUILD THE RIDGE DOWNSTREAM OF IT MORE INTO NORTHERN ONTARIO...FORCING THE SOUTHERN PORTION OF THE SHRTWV TROUGH OVER CENTRAL UPPER MICHIGAN SOUTHWARD. BY 12Z...THIS SHRTWV SHOULD REACH THE SOUTH BEND INDIANA AREA. ALTHOUGH THE SETUP LOOKS FAVORABLE FOR CLEARING SKIES... ESPECIALLY WITH THE SURFACE HIGH OVER NORTHERN ONTARIO CONTINUING TO STRENGTHEN AND LIFTING INTO HUDSON BAY...THE NE WINDS DEVELOP ON THE SE SIDE OF THE HIGH ARE EXPECTED TO ADVECT SOME OF THE LOWER CLOUDS CURRENTLY OVER EASTERN ONTARIO/WESTERN QUEBEC WESTWARD. IT APPEARS THAT BY 12Z THE WESTERN EXTENT OF THE LOW CLOUD LINE SHOULD BE THE LUCE COUNTY LINE...THOUGH MID AND HIGHER CLOUDS MAY MAKE IT TO ESCANABA. IN ANY EVENT...A DRY NIGHT IS EXPECTED GIVEN THE LOCATION OF THE LOW CLOUDS. THE COMBINATION OF SOME CLOUDS AROUND FROM THE SHRTWV TROUGH HEADING SOUTH AND A LITTLE WIND SHOULD KEEP TEMPERATURES FROM FALLING TOO FAR BELOW FREEZING. PREVIOUS LOW FORECAST SEEMS REASONABLE. WEDNESDAY...UPPER RIDGE OVER THE PLAINS INTO NORTHERN ONTARIO IS PROGGED TO REMAIN IN PLACE DUE TO TROUGHING STUCK OVER THE EASTERN U.S. (COMBINATION OF THE WEAKENING UPPER LOW OFF NEW JERSEY AND THE SHRTWV OVER SOUTH BEND MOVING SOUTH) AND THE SHRTWV TROUGH OVER NEVADA MOVING INTO UTAH. SINCE THE UPPER RIDGE REMAINS IN PLACE... THE SURFACE HIGH OVER HUDSON BAY SHOULD NOT MOVE MUCH EITHER. THUS...THE ENE WIND FLOW FROM THE SURFACE UP TO 500MB SHOULD ADVECT THE LOW...MID AND HIGH CLOUDS WESTWARD ACROSS THE CWA... PERHAPS REACHING IWD BY 00Z. BOTH THE NAM AND GFS GENERATE SOME QPF TOO WITH THE LOW CLOUDS...SINCE THE WINDS ARE ACTUALLY ADVECTING IN WARM AIR IN ALOFT FROM THE ATLANTIC (850MB TEMPS RISE FROM AROUND -3C AT ERY AT 12Z TO 0C AT 00Z). THIS IS ALREADY REPRESENTED WELL IN THE FORECAST...INCLUDING THE LOCATION. HOWEVER...WILL INCLUDE SOME CHANCE FOR PCPN IN MARQUETTE COUNTY ALSO IN THE MORNING SINCE NE BOUNDARY LAYER WINDS UPSLOPE. PCPN TYPE MAY ACTUALLY START OFF AS SNOW IN THE MORNING GIVEN MODEL SOUNDINGS MOSTLY BELOW ZERO...BUT AS THE BOUNDARY LAYER WARMS GRADUALLY THROUGH THE LATTER PART OF THE MORNING INTO THE AFTERNOON...THE SNOW WILL CHANGE OVER TO RAIN. COOLED HIGHS A FEW DEGREES MORE FROM THE PREVIOUS FORECAST... ESPECIALLY WITH THE CLOUD COVER. MET GUIDANCE IS 34F FOR SAWYER. WEDNESDAY NIGHT AND THURSDAY...MODELS SHOW THE EASTERN TROUGH FINALLY MOVING EASTWARD SOME...AND WITH THE SHRTWV TROUGH OVER NEVADA LIFTING UP INTO SOUTH DAKOTA BY 00Z FRI...THE UPPER RIDGE THAT WAS OVER THE DAKOTAS SHOULD BE ABLE TO HEAD TOWARDS THE CWA. IN FACT...BY 00Z FRI...THE RIDGE AXIS SHOULD BE CENTERED OVER UPPER MICHIGAN. WITH THE RIDGE MOVING IN...SUBSIDENCE SHOULD HELP GRADUALLY CLEAR OUT THE CLOUDS...AND PARTICULARLY ON THURSDAY WHEN THE EASTERLY WINDS SLACKEN AND DAYTIME HEATING HELPS OUT. IN ADDITION...ALTHOUGH EAST WINDS ARE CONTINUING...IT APPEARS THAT THERE WILL BE SOME DRY ADVECTION OCCURRING ON THURSDAY TOO FROM THE THE EAST...WHICH WILL HELP CLEARING SKIES OUT. THERE COULD BE SOME LINGERING PCPN IN THE EVENING WEDNESDAY...BUT GIVEN THAT IT IS A VERY SLIGHT CHANCE AT THIS POINT SINCE THE WARM ADVECTION WEAKENS... WILL NOT BOTHER MENTIONING. PLENTY OF CLOUDS WEDNESDAY NIGHT WILL HELP HOLD TEMPERATURES UP...AND THE PREVIOUS FORECAST LOWS IN THE LOW 30S SEEM REASONABLE. FOR THURSDAY...INCREASING SUNSHINE IN THE AFTERNOON AND 850MB TEMPS AROUND 0C SHOULD RESULT IN A WARMER DAY THAN WEDNESDAY...THOUGH STILL COOL BY THE LAKE SHORES WITH ONSHORE WINDS. HIGHS IN THE LOW 50S SHOULD BE ACHIEVABLE INLAND. THURSDAY NIGHT AND FRIDAY...ANOTHER STRONG SHRTWV TROUGH IS SHOWN TO DIG DOWN INTO SOUTHERN CALIFORNIA BY 00Z SAT. WITH RIDGING STUCK OVER THE CWA...THE SHRTWV TROUGH OVER THE DAKOTAS WILL HAVE TO LIFT NORTH...REACHING SOUTHERN MANITOBA FRI AFTERNOON. A PIECE OF THIS SHRTWV TROUGH MAY TRY TO CROSS THE CWA DURING THE DAY FRIDAY...BUT THE AIRMASS OVER THE CWA IS SHOWN TO BE WAY TOO DRY TO SUPPORT PCPN (DEWPOINT DEPRESSIONS MOSTLY BETWEEN 5 AND 20C FROM THE SURFACE TO 400MB). THUS THE GOING DRY FORECAST FOR THIS PERIOD IS REASONABLE. FEWER CLOUDS THURSDAY NIGHT...ALONG WITH DRIER AIR (PRECIPITABLE WATER NEAR 0.25 INCH) AND LIGHT WINDS SHOULD ALLOW TEMPERATURES TO DROP AT LEAST INTO THE MID 20S IN THE INTERIOR. MEX COOP GUIDANCE FOR CHAMPION IS 21. FOR FRIDAY...MORE SUNSHINE THAN ON THURSDAY ALONG WITH 850MB TEMPS OF 0-2C WILL ALLOW HIGHS TO RISE AT LEAST INTO THE MID TO UPPER 50S...SIMILAR TO TODAY. LAKE BREEZES DEVELOPING DUE TO LIGHT SURFACE WINDS SHOULD KEEP LAKESHORE LOCATIONS COOLER...WITH HIGHS OCCURRING AROUND NOON. THIS WEEKEND...THE SHRTWV TROUGH OVER SOUTHERN CALIFORNIA WILL GET KICKED OUT INTO THE PLAINS DUE TO ANOTHER EAST PACIFIC SHRTWV TROUGH MOVING IN. WARM ADVECTION DOWNSTREAM OF THE SHRTWV TROUGH MAY TRY TO BRING SOME ELEVATED SHOWERS TOWARDS UPPER MICHIGAN SATURDAY NIGHT...ASSUMING THE 00Z ECMWF IS CORRECT. THE UKMET AND THE GFS WOULD SUGGEST DRY INSTEAD. IN ANY EVENT...ALL OPERATIONAL LONG RANGE MODELS DEPICT A DRY SATURDAY EXCEPT OVER WESTERN LAKE SUPERIOR... THUS REMOVED SLIGHT CHANCE POPS. MODELS AGREE THAT THE KICKED OUT SHRTWV TROUGH WILL HEAD TOWARDS THE GREAT LAKES SUNDAY INTO MONDAY...BUT THERE ARE MAJOR TIMING DIFFERENCES BETWEEN THE ECMWF...GFS...CANADIAN AND UKMET. THUS POPS ARE WARRANTED FOR THE ENTIRE PERIOD. TEMPERATURES ARE TRICKY TOO DURING THIS PERIOD... ESPECIALLY SINCE 850MB TEMPS ARE PROGGED TO CLIMB TO 12C. IF A LOT OF SUN CAN OCCUR WHEN THESE HIGHER 850MB TEMPS ARE OVERHEAD (EITHER SATURDAY OR SUNDAY DEPENDING ON THE MODEL)...WE COULD SEE SOME 70 DEGREE READINGS. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 358 AM CDT TUE APR 17 2007 .DISCUSSION...FCST FOCUS ON PCPN TRENDS WITH FRONT AND DCVA THIS MRNG THEN ON FORMATION OF UPPER LOW OVR WRN GRT LAKES TNGT INTO WED. OVERALL COOLER REGIME TAKING HOLD WITH CHILLY NE WINDS. 1010MB SFC LOW VCNTY LSE AS OF 8Z. 2-3MB RISES IN WAKE OF FRONT. COLDEST TOPS ALONG WITH PCPN...EVEN TSTMS...ACRS NRN WI. SATELLITE TRENDS SHOW COLDEST TOPS ACRS NRN WI WITH NOT MUCH ALONG THE TAIL END. WATER VAPOR/RUC NICELY SHOWS ALL PCPN WITHIN DCVA REGION OF SHORT WAVE. H8 WARM AXIS ACRS CWA THIS MRNG THEN H8 TEMPS COLLAPSE AS DO 100-500MB THICKNESSES. WHILE MOISTURE A LIMITING FACTOR WITH FROPA THIS MRNG...GIVEN TIGHT H8 BARO ZONE AND PASSING OF H5 DCVA THIS MRNG...WILL KEEP A SML POP GOING ACRS MAINLY NE PTN OF THE CWA. GFS AND LOCAL WRF GENERATING QPF ACRS CWA WHILE NAM MORE SUBTLE. SPC SREF SEEMS TO LINE UP BEST WITH PRESENT TRENDS AND THEY INDICATE POPS OF ABOUT 10 OR LESS FOR THE CWA...SO WILL LEAN TOWARDS THE SLIGHTLY DRIER LOOK. GOOD CHANCE FOR HIGH TEMPS TO BE SET THIS MRNG AS THE WINDS SHIFT NE IN WAKE OF FROPA. CAA KICKS IN FOR THIS AFTN AND TNGT. MODELS TAKE SHORT WAVE AXIS AND EVOLVE UPPER ACRS LWR MI AND WHILE CORE OF LOW SHIFTS TO OUR SE ON WED...INFLUENCE OF THE CIRCULATION LINGERS INTO THU. H8-H7 MOISTURE INCREASES TNGT AND LINGERS THRU THU. H5 DOES SHOW SOME SPOKES OF VORT ROTATING ARND UPPER CIRCULATION ON WED THOUGH H7 OMEGA NOT IMPRESSIVE AT ALL. FOR NOW WILL LEAVE FCST DRY AS LOW LEVEL CONVERGENCE LACKING...SPC SREF NOT EXCITED AND SURROUNDING WFO/S GOING WITH THE DRY LOOK. FOR THURS THROUGH SATURDAY UPPER RIDGING WILL GRADUALLY TAKE HOLD WITH INFLUENCE OF SFC HI STILL EVIDENT DURG THIS PERIOD AS WELL. && 10 .AVIATION...BRIEF -SHRA /ISOLD T/ POSSIBLE THIS MORNING ESPECIALLY IN EASTERN AREAS /KMKE/ AS WEAKENING SHORT WAVE TROUGH AND LOW LEVEL THETA-E ADVECTION SLIDES THROUGH. NARROW BUT PERSISTENT BAND OF MVFR CIGS IN LOW LEVEL COLD AIR ADVECTION APPEARS TO BE EXPANDING ACRS ERN MN AND FAR WRN WI. WS-WRF HANDLING HIGH LOW LEVEL RH BEST AND DOES HINT AT POSSIBLE PERIOD OF LOWER CIGS IN SRN WI LATER TODAY. WL NEED TO WATCH THIS FEATURE CLOSELY THIS MORNING AS QUITE A BIT OF DRY AIR TO INITIALLY OVERCOME. BETTER CHANCE FOR MVFR CIGS TNGT AS LOW LEVELS MOISTEN AND INVERSION WEAKENS. && .MKX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 1010 AM EDT TUE APR 17 2007 .UPDATE... NO MAJOR UPDATES NEEDED TO THE FORECAST THROUGH THE REST OF THE DAYLIGHT HOURS. DID LOWER CLOUD COVER IN THE GRIDS A BIT AS MID/HIGH CLOUDS TO OUR WEST ARE HAVING A HARD TIME BREAKING THROUGH THE BUILDING UPPER RIDGE AND SHOULD ACTUALLY SEE A SKIES GOING MOSTLY SUNNY FOR A GOOD PORTION OF THE DAY. DYNAMICS THAT WILL BRING THE NEXT CHANCE OF SHOWERS TO OUR FORECAST AREA IS CURRENTLY CROSSING WEST TEXAS. UPPER LOW WILL EJECT INTO THE LOWER MISSISSIPPI VALLEY DURING TONIGHT WITH A WEAK ASSOCIATED SURFACE LOW REACHING NORTHERN LA TOWARD SUNRISE. CUT BACK ON POPS TONIGHT ACROSS THE AREA AS UPPER LEVEL RIDGING SHOULD REMAIN IN CONTROL. INTRODUCED A SLIGHT CHANCE OF SHOWERS AFTER MIDNIGHT ACROSS THE WEST...BUT EVEN THESE SHOWERS ARE LIKELY TO HOLD OFF UNTIL VERY LATE AS LATEST GFS/NAM SHOW BAST ISENTROPIC UPGLIDE AND MID/UPPER LEVEL Q-G FORCING NOT REACHING OUR WESTERN ZONES UNTIL AROUND 12Z WEDNESDAY. SHORTWAVE IS PROGGED TO SHEAR OUT WITH TIME AND WITH LITTLE MOISTURE RETURN AHEAD OF THE SYSTEM...SHOWERS SHOULD BE RATHER LIGHT WITH NOT MUCH TOTAL QPF TO SPEAK OF. COULD BE A HEAVIER DOWNPOUR OR ISOLATED THUNDERSTORM IN A BAND OF BETTER INSTABILITY CLOSER TO THE COAST...BUT THINK THESE WILL BE FEW AND FAR BETWEEN. TAPERED POPS QUICKLY FROM WEST TO EAST WEDNESDAY EVENING AS SHORTWAVE AND ASSOCIATED DYNAMICS FOR LIFT ARE GENERALLY EAST OF ALL BUT OUR FAR SOUTHEASTERN ZONES BY AROUND 06Z THURSDAY MORNING. WEAK COLD FRONT WILL SLIP SOUTH INTO THE COASTAL WATERS DURING THIS TIME FRAME AS WELL WITH DRIER AIR ARRIVING FROM THE NORTH AND NORTHWEST. && .MARINE... NORTHWEST WINDS CONTINUE ACROSS THE COASTAL WATERS THIS MORNING...GENERALLY BETWEEN 10 AND 15 KNOTS. OFFSHORE SEAS RUNNING AROUND 3 FEET AT THIS TIME. LATEST RUC SHOWING THESE WINDS HOLDING INTO THE EARLY AFTERNOON BEFORE SLOWLY DECREASING AND COMING AROUND TO THE WEST BY EARLY EVENING. THIS IS CLOSE TO THE CURRENT FORECAST AND SHOULD ONLY REQUIRE MINOR EDITS TO THE GRIDS FOR THE AFTERNOON HOURS. && .AVIATION... VFR CONDITIONS WILL PREVAIL THROUGHOUT THE FORECAST PERIOD...WITH INTERVALS OF SCT-BKN CIRRUS EXPECTED. SOME LOWER CLOUDS...WITH CIGS AROUND FL050...WILL DEVELOP THIS EVENING AT KPFN AND KDHN. WINDS TODAY WILL BE FROM THE NORTHWEST TO WEST UNDER 10 KNOTS...THEN BECOME LIGHT AND VARIABLE AFTER SUNSET THIS EVENING. && .FIRE WEATHER... RED FLAG WARNING REMAINS IN EFFECT FOR ALL ZONES IN SOUTHWEST AND SOUTH-CENTRAL GA AND ALSO FOR THE EASTERN FLORIDA PANHANDLE AND BIG BEND ZONES THIS AFTERNOON AND EARLY EVENING. CLOUD COVER AND INCREASED LOW LEVEL MOISTURE SHOULD HELP KEEP RH VALUES ABOVE CRITICAL LEVELS FOR WEDNESDAY. && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...RED FLAG WARNING FROM 2 PM EDT TO 7 PM EDT THIS AFTERNOON. FL...RED FLAG WARNING 12 PM EDT (11 AM CDT) UNTIL 9 PM EDT(8 PM CDT) TODAY. GM...NONE. && $$ MROCZKA/JAMSKI fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1035 AM EDT TUE APR 17 2007 .UPDATE...12Z SURFACE/RUC ANALYSIS AND VIS/IR/WV/RADAR IMAGERY SHOW DEEP UPPER LOW AND ASSOCIATED VORTICES ROTATING ACROSS THE NE CONUS. DEEPER MOISTURE ASSOCIATED WITH THIS UPPER LOW HAS BEEN NEARLY STATIONARY ON THE EASTERN SIDE OF THE SHEAR AXIS ACROSS THE LONG AXIS OF LAKE HURON. JUST TO THE WEST OVER LAKE MICHIGAN...WISCONSIN...AND LAKE SUPERIOR LIES A NARROW...MOISTURE STARVED SHORTWAVE THAT HAS PROGRESSING CLOSER TO THE CWA THIS MORNING. WEAK SURFACE REFLECTION OF THIS WAVE IS POSITIONED ACROSS SOUTHERN WISCONSIN WITH ITS WARM FRONT EXTENDING SOUTH ACROSS THE ILLINOIS AND INDIANA BORDER. MID-LEVEL BKN-OVC100 CLOUDS HAVE BEEN MOVING ACROSS NORTHWEST LOWER AND EASTERN UPPER WHILE RADARS AND SURFACE OBS FROM SURROUNDING WFOS SHOW SCATTERED SPRINKLES/LIGHT SHOWERS MOVE SOUTHEAST ACROSS NORTHERN WISCONSIN AND CENTRAL LAKE MICHIGAN. MANY OF THESE SHOWERS HAVE NOT BEEN REACHING THE GROUND DUE TO AN EXTREMELY DRY LOW LEVEL AIRMASS IN PLACE WITH A DEWPOINT DEPRESSION NOTED ON THE 12Z APX SOUNDING OF 32C AT 770MB. ALTHOUGH THE LOW LEVELS ARE MORE MOIST AROUND GRB (DEWPOINT DEPRESSIONS OF 10C BLOW 800MB)...THE CONVECTIVE NATURE OF THE PRECIP WITH 700-500MB LAPSE RATES OF 6-6.5 C/KM HAVE ALLOWED SOME OF THESE SHOWERS (AND ISOLATED THUNDERSTORMS) TO REACH THE GROUND OVER WISCONSIN. SHOWER POSSIBILITIES ARE THE MAIN FORECAST CONCERN FOR THE REST OF THE DAY. WILL SEE INCREASING CLOUDS OVER THE REST OF THE DAY WITH THE APPROACHING MID LEVEL WAVE/MOISTURE. MOST OF THE SHOWER ACTIVITY THAT HAS BEEN REACHING THE GROUND HAS BEEN MOVING IN THE SE DIRECTION NOW SE OF GRB WHERE HIGHER 850MB DEWPOINTS/THETA E RESIDES AND SEE NO INDICATION THAT THIS WILL CHANGE THIS AFTERNOON. WILL LEAVE A MENTION OF A SPRINKLE ACROSS NORTHWEST LOWER THROUGH EARLY AFTERNOON TO DEAL WITH THE DIMINISHING SHOWERS CROSSING THE LAKE MICHIGAN ATTM...BUT WILL REMOVE SPRINKLE MENTION ACROSS ALL CWA THEREAFTER AS THE WEDGE OF LOW LEVEL DRY AIR LOOKS TO ABSORB THE VIRGA. SW ZONES MAY RETURN TO PARTLY CLOUDY IF THE MID-LEVEL CLOUDS DISSIPATE BY LATE AFTERNOON OR EARLY EVENING...BUT ADDITIONAL CLOUD COVER ALONG AN 850MB FRONT WEST OF THE WAVE WILL KEEP SKIES ON THE MOSTLY CLOUDY SIDE ESPECIALLY ACROSS EASTERN UPPER AND THE TIP OF THE MIT. MPC && .AVIATION...CLOUDS WILL OVERSPREAD TVC/PLN BY 15Z...AND MOVE INTO APN AFTER MIDDAY. CLOUDS WILL BE MAINLY MID LEVEL (AOA 8000 FEET)...MAY CONTAIN SOME SPRINKLES OR LIGHT RAIN BUT DRY LOW LEVELS EXPECTED TO KEEP THREAT OF MEASURABLE PRECIP TO A MINIMUM. MAY SEE SOME BREAKS IN THE CLOUD COVER AROUND TVC LATER THIS AFTERNOON...MORE CLOUD COVER WILL ROTATE BACK INTO THE AREA FROM THE EAST LATER TONIGHT...ALONG WITH AN INCREASING THREAT FOR LIGHT RAIN/SNOW. JPB && .PREVIOUS DISCUSSION...ISSUED 359 AM EDT TUE APR 17 2007/ OVERALL PATTERN ACROSS NORTH AMERICA WILL BE SOMEWHAT BLOCKY THROUGH THE REMAINDER OF THE WEEK. A SERIES OF SHORT WAVE TROUGHS OVER THE PACIFIC WILL CARVE OUT A MEAN TROUGH ACROSS THE WEST...WHILE REMNANTS OF THE RECENT EAST COAST STORM SYSTEM LEAVE SOME PERSISTENT TROUGHING BEHIND ACROSS THE WESTERN ATLANTIC. RIDGING DEVELOPING BETWEEN THESE FEATURES WILL RESULT IN A BRIEF QUASI-OMEGA BLOCK PATTERN IN THE THURSDAY/FRIDAY TIME FRAME...WITH THE WESTERN GREAT LAKES EVENTUALLY COMING UNDER THE INFLUENCE OF THE UPPER LEVEL RIDGE. IN THE NEAR TERM... HOWEVER...INITIAL FORECAST CONCERNS WILL FOCUS ON A SHORT WAVE TROUGH CROSSING THE NORTHERN PLAINS THIS MORNING AND IMPACTS THIS FEATURE MAY HAVE LATER TODAY. ATTENTION THEN TURNS TO DEEP LAYER MOISTURE ROTATING AROUND REMNANTS OF EAST COAST STORM...AND PRECIPITATION CHANCES/TYPE WITH THIS FOR WEDNESDAY. TODAY/TONIGHT...03Z SURFACE ANALYSIS SHOWED HIGH PRESSURE RIDGE EXTENDING FROM NORTH/SOUTH ACROSS CENTRAL LAKE SUPERIOR/LAKE MICHIGAN/WESTERN IN...WITH A WEAKENING COLD FRONT EXTENDING FROM WESTERN ONTARIO...SOUTHWEST ACROSS NORTHWEST WI/SOUTHEAST MN. ASSOCIATED SHORT WAVE TROUGH WAS SLIDING ACROSS MN AND WESTERN LAKE SUPERIOR PER WV IMAGERY. AREA OF SHOWERS AND SOME THUNDERSTORMS WERE LOCATED AHEAD OF THIS WAVE ACROSS EASTERN MN/NORTHWEST WI/FAR WESTERN UPPER. 00Z MPX SOUNDING EXHIBITED A RATHER DEEP SURFACE BASED MIXED LAYER EXTENDING UP TO 700MB...WITH LAPSE RATES IN THE 700-500MB AT LEAST CONDITIONALLY UNSTABLE... THUS CONTRIBUTING TO UPSTREAM CONVECTIVE DEVELOPMENT. SOUNDINGS AT APX/GRB WERE QUITE DRY (DEW POINT DEPRESSIONS GENERALLY AOA 10C THROUGH 500MB)...AND AS A RESULT SKIES ACROSS NORTHERN MI WERE MAINLY CLEAR EARLY THIS MORNING. EASTWARD PROGRESS OF APPROACHING SHORT WAVE TROUGH EXPECTED TO BE IMPEDED BY CIRCULATION TO THE EAST...WITH MAIN ENERGY EVENTUALLY EXPECTED TO MAKE A TURN SOUTH AND CLOSE OFF A NEW MID LEVEL LOW ACROSS LOWER MI/WI LATER TONIGHT. MID LEVEL MOISTURE ASSOCIATED WITH THIS WAVE WILL SPREAD ACROSS THE FORECAST AREA TODAY... NORTHERLY LOW LEVEL FLOW WILL TRY TO KEEP DRY AIR IN PLACE BELOW 700MB...WHICH SHOULD LIMIT THREAT FOR MEASURABLE PRECIP TODAY BUT COULD AT LEAST SEE SOME SPRINKLES AT LEAST ACROSS MUCH OF NORTHERN LOWER. AS MID LEVEL LOW GETS ORGANIZED DEEP LAYER MOISTURE WILL INCREASE FROM THE EAST/NORTHEAST TONIGHT AS FLOW VEERS MORE FROM THAT DIRECTION. ANTICIPATE THAT THIS WILL RESULT IN AN INCREASE IN PRECIPITATION CHANCES FROM EAST TO WEST OVERNIGHT...VEERING FLOW WILL ALSO PULL COLDER AIR BACK INTO THE STATE TONIGHT. THIS MAY ERODE SURFACE BASED WARM LAYER DEPTH ENOUGH TO ALLOW FOR PRECIP TO MIX WITH OR CHANGE TO SNOW OVERNIGHT...ESPECIALLY IN HIGHER TERRAIN LOCALES WHERE IT IS MORE LIKELY BOUNDARY LAYER WILL COOL ENOUGH TO SUPPORT FROZEN PRECIP. WEDNESDAY...LIGHT PRECIPITATION LOOKS TO BE A PRETTY GOOD BET ON WEDNESDAY...NOT A LOT EXPECTED IN THE QPF DEPARTMENT AS OVERALL FORCING IS WEAK (WEAK ISENTROPIC ASCENT AND DEFORMATION ALONG NORTHERN HALF OF MID LEVEL LOW WHICH WILL BE SINKING INTO THE OHIO RIVER VALLEY. FORECAST SOUNDINGS SUGGEST PRECIP TYPE WILL BE PREDOMINANTLY SNOW WEDNESDAY MORNING...THEN CHANGING TO RAIN ASSUMING BOUNDARY LAYER RESPONDS TO LIMITED INSOLATION THOUGH SOME OF THIS WILL ALSO DEPEND ON HOW COLD TEMPERATURES ACTUALLY GET EARLY WEDNESDAY MORNING. PLAN TO GO PREDOMINANTLY SNOW NORTH OF M-55 WEDNESDAY MORNING...THEN KEEP THE RAIN/SNOW WORDING FOR THE AFTERNOON. WILL ALSO CONTINUE THE RAIN/SNOW MENTION INTO WEDNESDAY NIGHT ACROSS NORTHERN LOWER...SURFACE BASED WARM LAYER DEPTH FORECAST TO INCREASE WHICH WOULD SUPPORT MORE LIQUID PRECIP...BUT TO WHAT DEGREE IS IN DISPUTE AT THIS POINT. NO CHANGES MADE TO THE FORECAST BEYOND WEDNESDAY NIGHT. JPB && .APX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAND RAPIDS MI 908 AM EDT TUE APR 17 2007 .UPDATED... THERE IS CURRENTLY A LINE OF SHOWERS CROSSING LAKE MICHIGAN FROM WISCONSIN. THAT AREA OF SHOWERS IS ASSOCIATED WITH A SURFACE LOW OVER SOUTHERN WISCONSIN AT 12Z...PLUS UPPER LEVEL JET DIVERGENCE AND AN AREA OF MID LEVEL INSTABILITY. THERE IS ALSO AN AREA OF STEEP MID LEVEL LAPSE RATES ASSOCIATED WITH IT. THE RUC SHOWS THE 850 TO 500 LAPSE RATE NEAR 8C JUST SOUTH OF THE SURFACE LOW. THAT AREA TURNS SHARPLY SOUTHEAST BY MID MORNING...GETTING INTO EXTREME SW LOWER LATE THIS MORNING INTO EARLY THIS AFTERNOON. THERE IS ALSO UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE UPPER WAVE AS IT TO DIVES SOUTHEAST TODAY. DUE TO THE MOSTLY NORTHERLY WINDS FROM 850 TO NEAR 700 MB EAST OF US-131 THE SHOWERS WILL NOT GET FAR INLAND. THE 850 TO 500 MB LI STAYS POSITIVE WHILE THERE IS DECENT 1000 TO 850 MB THTE ADVECTION WEST OF US-131 INTO MID AFTERNOON. SO WHILE THERE WILL BE SHOWERS... I DO NOT BELIEVE WE WILL SEE THUNDERSTORMS WITH THIS TODAY. AS A RESULT OF ALL OF THAT AND THE LINE OF SHOWERS MOVING OVER LAKE MICHIGAN AS I WRITE THIS...I UPDATED THE ZONES TO ALLOW FOR SHOWERS OVER THE LINE OF COUNTIES ALONG THE LAKE SHORE TODAY. .PREVIOUS DISCUSSION... LATEST WV IMAGERY SHOWS A RIDGE AXIS ALMOST DIRECTLY OVER THE CWFA THIS MORNING. THIS RIDGE AXIS IS BEING SQUEEZED FROM THE SHORT WAVE TROUGH MOVING TOWARD THE REGION AND THE UPPER LOW THAT IS NEARLY STATIONARY OVER THE WRN ATLANTIC. THE MAIN FORECAST CHALLENGES THIS MORNING ARE FOCUSED ON THE PCPN CHCS AND PCPN TYPE BEGINNING TONIGHT AND CONTINUING THROUGH WED NIGHT AS THE SHORT WAVE APPROACHING FROM THE WEST CLOSES OFF OVER THE REGION. SFC OBS AND IR SATELLITE IMAGERY SHOW CLEAR SKIES CONTINUE TO BE FOUND OVER THE CWFA AS HAS BEEN THE CASE OVER THE PAST 24 HOURS. AS MENTIONED ABOVE...THE UPPER RIDGE AXIS IS OVERHEAD EARLY THIS MORNING. THIS RIDGE WILL MOVE EAST A LITTLE BEFORE IT GETS PINCHED OFF AS THE INCOMING SHORT WAVE INTERACTS/PHASES WITH THE UPPER LOW OVER THE WRN ATLANTIC THROUGH THE DAY TODAY. MID AND HIGH LEVEL CLOUD COVER ASSOCIATED WITH THE SHORT WAVE WILL INCREASE DURING THE DAY...HELPING SKIES BECOME PARTLY SUNNY. THERE IS A LITTLE BIT OF PCPN CURRENTLY ASSOCIATED WITH THIS WAVE...HOWEVER THIS PCPN IS MOVING INTO QUITE A DRY AIR MASS WITH DEW POINTS IN THE 20S OVER THE CWFA. IN ADDITION...MOST OF THE ENERGY WITH THIS SHORT WAVE WILL MOVE JUST NORTH OF THE CWFA THIS AFTERNOON. THEREFORE WE EXPECT THAT PCPN...IF ANY...THAT CAN SURVIVE THE DRY AIR IN PLACE WILL REMAIN NORTH OF THE CWFA. THUS WE WILL MAINTAIN THE DRY FORECAST. MAX TEMPS THIS AFTERNOON WILL LIKELY ECLIPSE YESTERDAY/S HIGHS BY A FEW DEGREES AS TEMPS THIS MORNING WILL NOT BE AS COLD AS YESTERDAY MORNING AND LOW LEVEL THICKNESSES SHOW A BIT OF AN INCREASE OVER YESTERDAY. PARTLY CLOUDY CONDITIONS THIS EVENING WILL BECOME CLOUDY DURING THE SECOND HALF OF THE NIGHT. THIS OCCURS AS THE SHORT WAVE THAT CLOSES OFF THIS AFTERNOON WILL BEGIN TO WRAP MID LEVEL MOISTURE CURRENTLY OVER THE NORTHEAST U.S./QUEBEC/ERN ONTARIO BACK OVER THE STATE. IN ADDITION...A FAIRLY STEADY NORTHEAST FLOW WILL DEVELOP AT THE SFC WHICH WILL HELP ADVECT LOWER MOISTURE INTO THE AREA TOWARD DAYBREAK WED MORNING. EVEN WITH MOISTURE BECOMING A BIT DEEP OVER THE CWFA LATER TONIGHT AND ON WED...FORCING IS QUITE LIMITED. ALL THE MODELS SHOW REALLY NO SHORT WAVE TROUGH ROTATING OVER THE CWFA...WEAK ISENTROPIC ASCENT OCCURS THROUGH EARLY WED WITH THE ADVECTION OF THE MOISTURE INTO THE AREA. ADDITIONAL WEAK FORCING COMES AS A RESULT OF THE CYCLONIC FLOW IN PLACE. PCPN WILL BECOME POSSIBLE LATE TONIGHT OVER THE NE COUNTIES AS THE DEEP MOISTURE WILL BE IN PLACE AND THE AFOREMENTIONED FORCING WILL BE ONGOING. THE BEST OPPORTUNITY ON WED WILL ALSO BE OVER THE NE WHERE WE WILL HAVE LIKELY POPS. AS FAR AS PCPN TYPE IS CONCERNED...FCST SOUNDINGS FROM THE REG GEM...GFS...AND NAM SUPPORT MAINLY RAIN FOR MOST OF THE CWFA THROUGH THE PERIOD. THERE WILL BE A WINDOW OF OPPORTUNITY FOR A FEW FLAKES OF SNOW AT THE ONSET OF PCPN AS SOME EVAP COOLING TAKES PLACE AND TEMPS ARE INITIALLY COOLER. HIGHS WILL LIKELY ONLY TOP OUT IN THE 40S WITH THE THICK CLOUD COVER AND PCPN AROUND. PCPN SHOULD DIMINISH A BIT WED EVENING AS THE UPPER LOW ROTATES SOUTH/SOUTHEAST OF THE CWFA. AS IT DOES SO...DRY AIR IN THE MID AND UPPER LEVELS ON THE BACKSIDE OF THE LOW WILL BECOME WRAPPED AROUND THE SYSTEM. ANY FORCING THAT WAS PRESENT ON WED WILL BECOME NON-EXISTENT BY 12Z THU. WE WILL KEEP A CHC OF SHOWERS IN FOR WED NIGHT WITH CYCLONIC FLOW STILL IN PLACE AND LOW LEVEL MOISTURE REMAINING. THEN DURING THE DAY ON THU...THE UPPER LOW WILL CONTINUE TO MOVE AWAY FROM THE CWFA...AND UPPER RIDGING WILL BEGIN TO TAKE CONTROL. LOW LEVEL MOISTURE WILL REMAIN PLENTIFUL AND WILL LIKELY BECOME TRAPPED UNDER THE STRENGTHENING SUBSIDENCE. SOME BREAKS IN THE CLOUDS WILL BE POSSIBLE ON THU...BUT WE EXPECT THAT THERE WILL BE MUCH MORE IN THE WAY OF CLOUD COVER. .LONG TERM... FRIDAY AND SATURDAY LOOK LIKE STELLAR DAYS AS HIGH PRESSURE DOMINATES BOTH ALOFT AND AT THE SURFACE. WILL GO MOSTLY SUNNY BOTH DAYS WITH VERY DRY AIR MASS IN PLACE. MODERATING TEMPERATURES CAN BE EXPECTED AS HEIGHTS GRADUALLY RISE. HIGHS FRIDAY SHOULD BE NEAR 60 AND PROBABLY WELL INTO THE 60S ON SATURDAY. THE MAIN QUESTION IS HOW SOON TO BRING IN THE NEXT CHANCE OF RAIN. ON SUNDAY A RETURN FLOW BEGINS TO KICK IN AHEAD OF A WAVE EJECTING NE THROUGH THE PLAINS. HOWEVER THE CHANCE FOR SHOWERS AND STORMS LOOKS PRETTY SLIM AS MODELS ARE ALL SIMILAR SHOWING FAIRLY HIGH AMPLITUDE RIDGING PERSISTING ALOFT. THE POTENTIAL EXISTS FOR TEMPS TO SOAR WELL INTO THE 70S SUNDAY... WITH 12C H8 AIR PROGGED TO INVADE THE STATE. IF MODELS MAINTAIN THIS TREND WE`LL HAVE TO BUMP UP CURRENT FCST HIGHS. A LITTLE BETTER CHANCE FOR SHOWERS AND STORMS APPEARS TO EXIST FOR NEXT MONDAY AS THAT PLAINS SYSTEM CONTINUES NORTHEASTWARD AND BREAKS DOWN THE UPPER RIDGE. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE. && $$ NJJ MEADE WDM mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 654 AM CDT TUE APR 17 2007 .UPDATE... SUNRISE SURPRISE STRATUS/STRATCU GREETING EASTERN MN AND PARTS OF WESTERN WI THIS MORNING. TAMDAR SOUNDING FROM MSP SHOWS AN INVERSION BETWEEN 2K AND 3K FEET WHERE A FAIRLY ABRUPT WIND SHIFT OCCURS. THE RUC MODEL HAS AN EXCELLENT HANDLE ON THIS AND THE HIGH RH AT THE CORRESPONDING PRESSURE LEVELS. THIS DISSIPATES THE CLOUDS AS THE LOW LEVEL FLOW ALIGNS MORESO BY LATE MORNING AND MIXING GETS GOING. WESTERN WI THOUGH APPEARS NOW TO BE UNDER STRATOCU MORESO DURING THE DAY GIVEN THE TRAJECTORY OF THESE CLOUDS AND HINTS AT AN INVERSION ON THE PROGGED SOUNDINGS NEAR EAU ALL DAY. SO HAVE LOWERED MAXS 3-6F OVER WESTERN WI AND 2-3F OVER EASTERN MN. ALSO TWEAKED THE TEMP TREND AS IT SHOULD BE SLOW TO INCREASE THIS MORNING. && .PREV DISCUSSION... /ISSUED 335 AM CDT TUE APR 17 2007/ DISCUSSION... AMPLE SUNSHINE IS ANTICIPATED THROUGH MIDWEEK WHICH WILL OFFSET THE NORTHEAST WINDS AND KEEP TEMPERATURES SLIGHTLY ABOVE NORMAL. A MORE ACTIVE WEATHER PATTERN WITH STRONGER WARM AIR RETURN THEN LOOKS TO SET UP FROM THURSDAY NIGHT THROUGH THE WEEKEND. LATEST SURFACE ANALYSIS SHOWS FRONT WHICH WENT THROUGH LAST NIGHT NOW DRAPED TO OUR SOUTHEAST WITH SURFACE SURFACE PRESSURE RISES CONTINUING TO USHER IT AWAY. THE HIGH PRESSURE AIR MASS BUILDING IN IS NOT PARTICULARLY DRY AND HIGHER DEW POINTS AND SOME CLOUDS ARE EXPECTED TO LAG IN WESTERN WI AND SOUTHERN MN TODAY. MIXING TODAY IN SUNNY AREAS LOOKS TO BE NEAR 850MB...OVER 100MB BELOW YESTERDAY. ADD TO THAT THE LOWER TROPOSPHERE HAS COOLED OFF SEVERAL DEGREES C WITH THE FRONT PASSAGE. USING UPSTREAM TEMPS FROM YESTERDAY AND PROGGED H8 TEMPS STILL YIELD ABOVE NORMAL FORECAST HIGHS TODAY THOUGH...GENERALLY 60 TO 65F FORECAST AREA WIDE. THE POWERFUL SYSTEM THAT HAS AND CONTINUES TO IMPACT THE NORTHEAST CONUS WILL KEEP THE WEATHER OVER THE NORTH CENTRAL U.S. FROM CHANGING MUCH THROUGH 48 TO 60 HOURS. THE RIDGE AXIS LOOKS TO EXTEND FROM WESTERN QUEBEC DOWN INTO THE FORECAST AREA TONIGHT INTO WEDNESDAY WITH TRANQUIL WEATHER. SOME POTENTIAL FOR LIGHT FOG DOES EXIST IN A FEW PLACES TONIGHT. A SERIES OF POTENT SYSTEMS ARE EXPECTED TO MOVE INTO THE WESTERN CONUS THROUGH THE NEXT FIVE DAYS...WITH EACH ONE PROGRESSIVELY BREAKING DOWN THE UPPER RIDGE OVER OUR AREA. AS THESE EJECT INTO THE PLAINS THEY BEGIN TO BRING CHANCES FOR RAIN THURSDAY NIGHT AND EARLY FRIDAY...AND A BETTER CHANCE DURING THE WEEKEND. HOWEVER...THE WHOLE WEEKEND CERTAINLY DOES NOT LOOK TO BE A WASHOUT. STRONGER WARM AIR ADVECTION AT THE SURFACE SHOULD PRODUCE TEMPERATURES PUSHING AT OR ABOVE 70 THOUGH ON SATURDAY AND POSSIBLY SUNDAY. THE MOST POTENT OF THE SYSTEMS IN VIEW AT THIS TIME OCCURS ON SUNDAY WHICH HAS A NEGATIVE TILT AND SUB 1000MB LOW. H5 LOW AND BEST SEVERE CHANCES ARE PROGGED AT THIS TIME TO PASS TO THE SOUTH BUT STILL CONFIDENCE IS INCREASING FOR CONVECTION DURING THE LATTER HALF OF THE WEEKEND GIVEN JET ORIENTATION AND INSTABILITY. THE ONE TO TWO WEEK OUTLOOK FROM HPC EXPRESSES CONFIDENCE THAT TEMPERATURES MAY BE BACK NEAR NORMAL FOR THE FINAL WEEK OF APRIL. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MTF mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 330 PM EDT TUE APR 17 2007 .SYNOPSIS... 18Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUES TO SHOW AN UPPER AIR PATTERN HIGHLIGHTED BY THE LARGE LOW SPINNING OFF THE NORTHEAST COAST AND A WEAK CLOSED LOW MOVING OUT OF THE SOUTHWEST U.S. INTO THE SOUTHERN PLAINS. ANOTHER WEAKER SHORTWAVE IS SEEN RIDING THE NORTHERN STREAM INTO THE WESTERN GREAT LAKES. THIS SHORTWAVE IS PROGGED TO CLOSE OFF AS IT CROSSES THE SOUTHERN GREAT LAKES/OHIO VALLEY TONIGHT. ACROSS OUR AREA...MID/UPPER LEVEL RIDING CONTINUES TO DOMINATE. SOME MID/HIGH LEVEL CLOUDS TO OUR WEST HAVE HAD A HARD TIME BREAKING THROUGH THIS UPPER RIDGING SO FAR TODAY RESULTING IN GENERALLY JUST ENOUGH CIRRUS TO FILTER THE SUN AT TIMES. AT THE SURFACE...HIGH PRESSURE OVER THE LOWER MISSISSIPPI VALLEY WILL CONTINUE TO SLIDE SOUTHEAST AND WEAKEN THIS EVENING AND OVERNIGHT AS IT BECOMES CENTERED OVER THE EASTERN GULF OF MEXICO. TEMPERATURES HAVE REBOUNDED BACK INTO THE 70S WITH A CONTINUED NORTHWEST FLOW. THESE TEMPERATURES HAVE COMBINED WITH DRY LOW LEVEL AIR TO PRODUCE SOME VERY LOW RH VALUES ACROSS MUCH OF THE FORECAST AREA. && .SHORT TERM (TONIGHT THROUGH FRIDAY)... UPPER LEVEL LOW CURRENTLY OVER TEXAS WILL OPEN UP AS IT EJECTS EASTWARD INTO THE LOWER MISSISSIPPI VALLEY TONIGHT. ASSOCIATED SURFACE LOW WILL COME TO A POSITION OVER NORTHERN LOUISIANA BY SUNRISE WEDNESDAY MORNING WITH A TRAILING COLD FRONT INTO THE WESTERN GULF OF MEXICO. WARM FRONT AT THIS TIME SHOULD EXTEND EAST FROM THE LOW CENTER ALONG OR JUST NORTH OF THE GULF COAST INTO OUR FORECAST AREA. DESPITE SOME FAIRLY DECENT HEIGHT FALLS DURING THE LATE NIGHT HOURS OVER THE WESTERN CWA...THE LACK OF MOISTURE RETURN AHEAD OF THE SYSTEM WILL LIKELY KEEP THE LOWER LEVELS TO DRY TO SUPPORT ANY MEASURABLE QPF DURING THE OVERNIGHT HOURS. IN FACT THE LATEST NAM/GFS FORECAST SOUNDINGS FOR 12Z WEDNESDAY STILL SHOW DEWPOINT DEPRESSIONS JUST ABOVE THE SURFACE BETWEEN 25-30C. SO WITH THIS IN MIND...WILL NOT BE EXPECTING MUCH OF ANY SHOWER ACTIVITY...EVEN IN THE WEST THROUGH THE NIGHT. CURRENTLY RUNNING A SLIGHT 20 POP FOR THE WEST HALF OF THE AREA AFTER MIDNIGHT AND LIKELY WILL TRIM THIS BACK TO ONLY THE FAR WEST IN THE VERY LATE NIGHT HOURS FOR A FEW LIGHT SHOWERS OR SPRINKLES. WITH ONLY SOME HIGH CLOUDS...DRY CONDITIONS AND HIGH PRESSURE IN THE VICINITY...WE SHOULD SEE TEMPS DROP FAIRLY QUICKLY DURING THE EVENING HOURS. GOING FOR LOW TEMP GENERALLY IN THE UPPER 40S TO LOWER 50S INLAND AND IN THE 50S CLOSER TO THE COAST. TEMPERATURES MAY HOLD STEADY OR FALL VERY SLOWLY AFTER MIDNIGHT WITH HIGH CLOUDS BECOMING MORE ABUNDANT. LOW LEVEL PROFILES DO SLOWLY MOISTEN THROUGH THE MORNING HOURS ON WEDNESDAY WITH THE HELP OF SOME WEAK ISENTROPIC UPGLIDE ALONG THE 295-300K SURFACES. THIS MOISTENING ALONG WITH THE SHORTWAVE PASSAGE...IS LIKELY TO ALLOW AT LEAST SOME SCATTERED SHOWER ACTIVITY AND MEASURABLE QPF INTO SOUTHEAST AL/FLORIDA PANHANDLE DURING THE MORNING/EARLY AFTERNOON HOURS. SHOWER ACTIVITY WILL LIKELY HAVE A HARD TIME REACHING THE EASTERN FORECAST AREA UNTIL THE AFTERNOON HOURS...AND EVEN THEN LOOKS TO ONLY BE SPOTTY. WITH THE WEAKENING SHORTWAVE DYNAMICS...THE FAIRLY QUICK PASSAGE OF THESE DYNAMICS THROUGH THE DAY AND A VERY DRY ATMOSPHERE TO OVERCOME...DO EXPECT RAINFALL TOTALS TO BE QUITE LOW IN MOST LOCATIONS. INSTABILITY IS ALSO QUITE LACKING WITH THIS SYSTEM. WILL INCLUDE ISOLATED TSTORM IN THE GRIDS DURING THE LATE MORNING AND AFTERNOON CLOSE TO THE FLORIDA COASTLINE...BUT CONVECTION SHOULD CERTAINLY HAVE A HARD TIME GETTING GOING EVEN HERE SINCE THE LATEST SREF ENSEMBLES ARE SHOWING ONLY 200-300 J/KG OF MUCAPE AND THE GFS AND NAM KEEP THEIR SHOWALTER INDEX FORECAST ABOVE ZERO. THE TEMPERATURE FORECAST FOR WEDNESDAY IS RATHER TRICKY. EVAPORATION OF THE LIGHT SHOWERS MAY PARTIAL COUNTERACT DIURNAL HEATING FOR A TIME. WENT WITH AN OPTIMISTIC MIDDLE 70S FORECAST FOR MOST LOCATIONS AS GUIDANCE IS FAIRLY CLUSTERED AROUND THIS SCENARIO...HOWEVER IF THE EVAPORATIVE COOLING AND/OR CLOUDCOVER IS A BIT STRONGER/THICKER THAN EXPECTED THAN TEMPERATURES MAY VERIFY A FEW DEGREES COOLER. VERY WEAK LOW PRESSURE SLIPS SOUTH OF THE FORECAST AREA INTO THE COASTAL WATERS WEDNESDAY NIGHT. THE FRONTAL SYSTEM OVER THE AREA WILL SINK SOUTH AS A COLD FRONT WITH THE SYSTEM ALLOWING WINDS TO COME BACK TO THE NORTH AND NORTHWEST AND DRIER AIR TO BEGIN FLOWING BACK INTO THE REGION. THE TAIL END OF THE LARGE SCALE DYNAMICS WILL BE EXITING THE REGION EARLY WITH PERHAPS A FEW EVENING SHOWERS IN THE SOUTH AND EAST...BUT EXPECT ALL AREAS TO BE DRY BY THE EARLY MORNING HOURS OF THURSDAY. LINGERING CLOUD COVER WILL ALSO BEGIN TO BREAK FROM NORTH TO SOUTH DURING THE LATE NIGHT HOURS. THURSDAY INTO THURSDAY NIGHT WILL SEE A POTENT SHORTWAVE DROP SOUTH FROM THE OHIO VALLEY TO THE CAROLINA COASTLINE. WEAK SURFACE LOW ASSOCIATED WITH THIS UPPER LEVEL FEATURE WILL REMAIN TO OUR NORTHEAST BUT IS PROGGED TO DRAG A RE-ENFORCING COLD FRONT THROUGH THE FORECAST AREA THURSDAY NIGHT. AT THIS TIME...GUIDANCE AGREES THAT THE BEST DYNAMICS FOR LIFT WILL REMAIN FAR ENOUGH NORTH AND EAST TO LEAVE US DRY FOR THIS EVENT...HOWEVER...IF THE SHORTWAVE WERE ABLE TO DIG A BIT FURTHER SOUTH AND WEST THEN A SHOWER MIGHT BE POSSIBLE ACROSS SOUTH-CENTRAL GEORGIA. THIS SCENARIO SEEMS REMOTE AT THIS POINT. THE PASSAGE OF THE COLD FRONT ON THURSDAY NIGHT WILL USHER IN SURFACE HIGH PRESSURE ON GUSTY NORTHERLY WINDS FOR THE DAY ON FRIDAY. HIGH TEMPERATURES THURSDAY AHEAD OF THE FRONT SHOULD MIX OUT INTO THE UPPER 70S NORTH TO LOWER 80S SOUTH...THEN DOWN SLIGHTLY INTO THE MIDDLE 70S TO NEAR 80 FOR FRIDAY. && .LONG TERM (FRIDAY NIGHT THROUGH TUESDAY)... CONTINUED DRIER AND WARMER CONDITIONS THROUGH THE UPCOMING WEEKEND AS UPPER LEVEL RIDGE BUILDS ACROSS THE ERN CONUS AND A SFC RIDGE ADVANCES EAST ACROSS MID CONUS...THEN TO OFFSHORE OF THE MID-ATLANTIC COAST THIS WEEKEND. UPSTREAM...AN UPPER TROUGH AND SFC LOW WILL MOVE NORTHEAST ACROSS THE PLAINS LATE IN THE WEEKEND. ASSOCIATED SHORT WAVE LIFTS FROM THE CENTRAL PLAINS SUNDAY TO THE GREAT LAKES REGION BY LATE MONDAY FLATTENING THE UPPER RIDGE. THE ASSOCIATED COLD FRONT STALLS WELL TO OUR NORTH AS IT LAYS OUT EAST TO WEST ACROSS THE TENNESSEE VALLEY ON MONDAY. HIGH TEMPS INLAND WILL LINGER AROUND 80 THRU PERIOD. && .MARINE... WEAKENING HIGH PRESSURE MOVES SOUTH OF THE FORECAST WATERS THIS EVENING THEN FALLS APART AS IT CROSSES THE FLORIDA PENINSULA OVERNIGHT. WEAK LOW PRESSURE WILL THEN APPROACH FROM THE WEST WEDNESDAY WITH A WARM FRONT EXTENDING EAST OVER OR JUST NORTH OF THE WATERS THROUGH THE EVENING HOURS. THE GRADIENT IS EXPECTED TO BRIEFLY TIGHTEN AHEAD OF THIS SYSTEM WEDNESDAY WITH WINDS APPROACHING CAUTION LEVELS FOR A TIME. WEAK FRONT ASSOCIATED WITH THE LOW THEN SINKS SOUTH THROUGH THE WATERS WEDNESDAY NIGHT INTO EARLY THURSDAY. HIGH PRESSURE BRIEFLY BUILDS OVER THE AREA THURSDAY BEFORE ANOTHER RE-ENFORCING COLD FRONT CROSSES THE WATERS THURSDAY NIGHT. HIGH PRESSURE WILL FOLLOW THIS FRONT FOR FRIDAY AND THE UPCOMING WEEKEND. DO EXPECT A PERIOD OF CAUTION TO PERHAPS ADVISORY LEVEL WINDS FOR A PERIOD LATE THURSDAY NIGHT OR FRIDAY BEFORE DIMINISHING ON SATURDAY. && .AVIATION... VFR CONDITIONS TO CONTINUE THROUGH THE OVERNIGHT HOURS. APPROACHING SHORTWAVE AND LOW PRESSURE SYSTEM WILL INCREASE MOISTURE ENOUGH TO GENERATE CLOUDINESS AND MAYBE A FEW SHOWERS WEDNESDAY. RAIN CHANCES NOT HIGH ENOUGH ATTM TO WARRANT TEMPO GROUPS. LOW LEVEL MOISTURE WILL REMAIN LIMITED AS WELL...SO EXPECT CEILINGS TO REMAIN MOSTLY VFR. && .FIRE WEATHER... RED FLAG WARNINGS FOR OUR FLORIDA AND GEORGIA COUNTIES LOOK TRACK AS OF MID AFTERNOON WITH RH VALUES ALREADY WELL BELOW CRITICAL LEVELS. ALABAMA IS NOW SEEING VALUES APPROACH CRITICAL LEVELS BUT DURATIONS LONG ENOUGH TO ISSUE A NEW RED FLAG SEEM UNLIKELY. A BIT MORE LOW LEVEL MOISTURE AND COOLER TEMPS ON WEDNESDAY ALONG WITH RAIN CHANCES SHOULD KEEP THINGS IN CHECK. BEHIND A WEAK FRONT WEDNESDAY NIGHT DRY LOW LEVEL AIR WILL ONCE AGAIN FLOW INTO THE REGION. A FIRE WEATHER WATCH HAS BEEN ISSUED FOR THE EASTERN FLORIDA PANHANDLE AND FLORIDA BIG BEND FOR POSSIBLE LONG DURATIONS OF RH BELOW 35 PERCENT. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 48 76 54 81 51 / 10 30 20 0 0 PANAMA CITY 58 74 58 79 56 / 10 30 20 0 0 DOTHAN 51 74 52 78 48 / 10 40 10 0 0 ALBANY 47 75 50 79 49 / 10 30 10 0 0 VALDOSTA 47 78 53 80 51 / 05 30 20 0 0 CROSS CITY 48 79 55 81 52 / 05 30 20 05 0 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...RED FLAG WARNING UNTIL 7 PM EDT THIS EVENING FOR THE FOLLOWING ZONES: BAKER...BEN HILL...BERRIEN...BROOKS...CALHOUN... CLAY...COLQUITT...COOK...DECATUR...DOUGHERTY...EARLY... GRADY...IRWIN...LANIER...LEE...LOWNDES...MILLER... MITCHELL...QUITMAN...RANDOLPH...SEMINOLE...TERRELL... THOMAS...TIFT...TURNER...WORTH. FL...RED FLAG WARNING UNTIL 9 PM EDT /8 PM CDT/ THIS EVENING FOR THE FOLLOWING ZONES: BAY...CALHOUN...DIXIE...FRANKLIN... GADSDEN...GULF...HOLMES...INLAND WALTON...JACKSON... JEFFERSON...LAFAYETTE...LEON...LIBERTY...MADISON...TAYLOR... WAKULLA...WASHINGTON. FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY EVENING FOR THE FOLLOWING ZONES: BAY...CALHOUN...FRANKLIN... GADSDEN...GULF...HOLMES...INLAND WALTON...JACKSON... JEFFERSON...LEON...LIBERTY...MADISON...TAYLOR...WAKULLA... WASHINGTON. GM...NONE. && $$ AVIATION/FIRE WX...CAMP LONG TERM...BLOCK PUBLIC/MARINE....MROCZKA fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 328 PM EDT TUE APR 17 2007 .SYNOPSIS... A LARGE AREA OF LOW PRESSURE SOUTH OF NOVA SCOTIA WILL SLOWLY MOVE AWAY TO THE SOUTHEAST THROUGH THURSDAY. HIGH PRESSURE WILL BUILD INTO THE AREA FRIDAY AND REMAIN OVER THE REGION THROUGH THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... EXTENDED HIGH WIND WARNINGS OUT THROUGH 2 AM AND KEPT THE COASTAL FLOOD WARNING AS IS. EVERYTHING ELSE WAS PULLED DOWN. LEANED CLOSE W/A NAM-RUC BLEND TONIGHT AS THIS BLEND MATCHES UP WELL PER LATEST SATL IMAGERY AND RADAR. BROUGHT POPS WAY DOWN ACROSS NERN MAINE TONIGHT AS 12Z UA SHOWED SOME DRYING AT 850 MBS W/SOME NVA WORKING WWD. FURTHER BACK TO THE W & DOWN TO THE S & E...STAYED W/CATEGORICAL POPS. MADE ADJUSTMENTS TO QPF TO HAVE THE HIGHEST AMOUNTS ACROSS THE EXTREME ERN AREAS AND COASTAL SECTION OF THE CWA BY 06Z. PRECIP AXIS PIVOTS SEWD OVERNIGHT AS LOW STARTS TO PULL AWAY. FLOOD WATCH IN PLACE. ADDITIONAL QPF AMOUNTS OF UP TO .50 INCHES FOR THE ERN & COASTAL AREAS TONIGHT W/ONLY UP TO A A TENTH OF AN INCH OR SO FURTHER N & W. PRECIP TYPE WILL BE TRICKY ESP ACROSS NERN & WRN AREAS WILL TEMPS OVERNIGHT WILL HOVER NEAR THE FREEZING MARK. OPTED TO GO W/JUST RAIN OR SNOW & LEFT OUT ANY MENTION OF SLEET OR FREEZING RAIN ATTM. ANY SNOWFALL ACCUMULATIONS WILL BE ACROSS THE FAR N & W & OVER HIGHER TERRAIN WHERE UP TO AN INCH IS POSSIBLE. ADJUSTED WINDS MAINLY FOR NRN AREAS TO LOWER THEM AS PRES GRADIENT LOOSENS OVERNIGHT AND AXIS SHIFTS TO THE ERN 3RD OF THE CWA PER LATEST NAM/RUC. WINDS WILL BE STRONGEST ALONG THE COAST AND HIGH TERRAIN. SUSTAINED WINDS WILL REMAIN WELL BELOW ADV/WARNING CRITERIA. HOWEVER...WINDS GUST COULD HIT 45 TO 50 MPH AND W/SATURATED SOIL...IT WILL NOT TAKE MUCH TO BRING TREES DOWN AS HAS BEEN REPORTED TODAY. COASTAL FLOODING CONCERNS REMAIN THROUGH TONIGHT. ONE MORE TIDE TO DEAL W/AT 1130 PM OR SO. SOME PROBLEMS WERE REPORTED EARLIER THIS MORNING OVER HANCOCK COUNTY AND PORTIONS OF WASHINGTON COUNTY. THINGS SHOULD WIND DOWN AFT 06Z. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... THE BIG LOW PRESSURE SYSTEM WHICH BROUGHT WIND...RAIN AND SNOW EARLY THIS WEEK WILL SLOWLY BACK AWAY TO THE SOUTHEAST AND OUT INTO THE OPEN ATLANTIC WEDNESDAY THROUGH THURSDAY. STRATUS CLOUDS WILL LINGER WEDNESDAY WITH SOME LIGHT RAIN SHOWERS...OR SNOW SHOWERS OVER THE HIGHER ELEVATIONS. BREAKS IN THE OVERCAST MAY ALLOW SOME SUNSHINE OVER THE NORTH DURING THE MIDDAY AND AFTERNOON WEDNESDAY. MOISTURE CONTINUING TO CIRCULATE AROUND THE LOW WILL BRING CONTINUED MOSTLY CLOUDY SKIES AND CHANCES FOR SHOWERS ON THURSDAY WITH THE BRIGHTEST SKIES OVER THE FAR NORTH WHERE SOME BREAKS OF SUNSHINE WILL BE POSSIBLE. && .LONG TERM /FRIDAY THROUGH TUESDAY/... OUR LONG AWAITED SPRING WILL BE UPON US AT THE END OF THIS WEEK AS A LARGE HIGH PRESSURE SYSTEM BUILDING DOWN FROM CANADA BRINGS PLENTY OF SUNSHINE...LIGHT WINDS AND TEMPERATURES INTO THE 50S FRIDAY...SATURDAY AND AGAIN ON SUNDAY. THE STRONG LATE APRIL SUNSHINE MELTING SNOW WILL LIKELY RESULT IN SIGNIFICANT RISES OF STREAMS AND RIVERS. EARLY NEXT WEEK LOW PRESSURE PASSING TO OUR NORTH THROUGH CANADA WILL PULL A COUPLE WEAK FRONTAL PASSAGES THROUGH. THIS MAY BRING SHOWERS THROUGH LATE SUNDAY NIGHT. BOUNDARY LAYER TEMPS WILL BE WARM MONDAY...BUT A SOUTH WIND COULD PULL COOLER AIR NORTH FROM THE OCEAN LIMITING TEMPERATURES RISES NEAR THE GROUND MONDAY. TUESDAY WILL THEN LIKELY BE DRY...BREEZY AND SEASONABLE FOLLOWING A COLD FRONTAL PASSAGE. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... IFR CONDITIONS ARE EXPECTED TO CONTINUE IN LOW CLOUDINESS TONIGHT INTO EARLY WEDNESDAY...WITH CONDITIONS POSSIBLY IMPROVING TO MVFR LATE WEDNESDAY. MVFR CONDITIONS ARE LIKELY THROUGH THURSDAY IN CONTINUING STRATUS CLOUDS. A BIG HIGH PRESSURE BUILDING IN LATE IN THE WEEK SHOULD BRING VFR CONDITIONS FRIDAY THROUGH THE WEEKEND. && .MARINE... STORM FORCE GUSTS EXPECTED THIS EVENING W/ONE SURGE AND THEN THE STRONGER WIND AXIS SHIFT WELL E AND SE OF THE CWA. SEAS RUNNING 16-19 FT PER LATEST REPORTS. EXPECT THOSE SEAS TO COME DOWN AS WELL OVERNIGHT. THE STRONG GRADIENT AROUND LOW PRESSURE OUT IN THE ATLANTIC WILL RESULT IN GALE WINDS WEDNESDAY INTO WEDNESDAY NIGHT...THEN SCA WINDS THURSDAY INTO THURSDAY NIGHT. HIGH PRESSURE FRIDAY INTO THE WEEKEND WILL THEN BRING A TREND TOWARD MORE TRANQUIL CONDITIONS. && .HYDROLOGY... AS STATED ABV...FFA REMAINS IN PLACE. SOME MINOR PROBLEMS REPORTED BUT W/ANOTHER SLUG OF RAFL COMING TO ERN & DOWNEAST SECTIONS...THIS COULD CHANGE OVERNIGHT. SOME SMALLER STREAMS AND RIVERS IN WASHINGTON AND HANCOCK COUNTY RUNNING HIGH AND IN ACTION STAGE. ADDITIONAL RAFL COULD ALLOW FOR SOME OF THESE STREAMS TO GO OVER THEIR BANKS. CONDITIONS NEED TO BE MONITORED EVEN FURTHER BACK TO THE N & W AS THERE IS QUITE A BIT OF WATER IN SNOWPACK. TEMPERATURES ARE FCST TO WARM OVER THE NEXT FEW DAYS ALLOWING FOR MELTING AND RUNOFF TO TAKE PLACE. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...HIGH WIND WARNING UNTIL 2 AM EDT WEDNESDAY FOR MEZ011-015>017- 029-030-032. FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR MEZ005-006-011- 015>017-029>032. MARINE...STORM WARNING UNTIL 9 PM EDT THIS EVENING FOR ANZ050. && $$ NEAR TERM...HEWITT SHORT TERM...BLOOMER LONG TERM...BLOOMER AVIATION...HEWITT MARINE...HEWITT/BLOOMER HYDROLOGY...HEWITT/TURNER me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 120 PM EDT TUE APR 17 2007 .AVIATION...A WEAK TROUGH WILL CONTINUE TO SPREAD A MID-LEVEL CLOUD DECK ACROSS THE TAF SITES. A FEW SPRINKLES MAY BE POSSIBLE NEAR TVC...BUT CONDITIONS WILL REMAIN VFR INTO THIS EVENING. AS THIS TROUGH MERGES WITH THE DEEP EAST COAST CYCLONE TONIGHT...LOW LEVEL MOISTURE WILL MOVE BACK INTO THE AREA FROM THE EAST. THIS WILL ALLOW FOR LOWERING CLOUD BASES INTO MVFR TERRITORY AND LIGHT RAIN/SNOW SHOWERS DEVELOPING AT APN FIRST...THEN PLN AND TVC AFTER MIDNIGHT. JUDGING BY CLOUD HEIGHTS OVER EASTERN ONTARIO AND QUEBEC...WILL KEEP IFR CONDITIONS OUT OF THE TAFS FOR NOW...BUT MVFR CONDITIONS WILL CONTINUE TO LAST THROUGH EARLY AFTERNOON TOMORROW. MPC && .UPDATE...12Z SURFACE/RUC ANALYSIS AND VIS/IR/WV/RADAR IMAGERY SHOW DEEP UPPER LOW AND ASSOCIATED VORTICES ROTATING ACROSS THE NE CONUS. DEEPER MOISTURE ASSOCIATED WITH THIS UPPER LOW HAS BEEN NEARLY STATIONARY ON THE EASTERN SIDE OF THE SHEAR AXIS ACROSS THE LONG AXIS OF LAKE HURON. JUST TO THE WEST OVER LAKE MICHIGAN...WISCONSIN...AND LAKE SUPERIOR LIES A NARROW...MOISTURE STARVED SHORTWAVE THAT HAS PROGRESSING CLOSER TO THE CWA THIS MORNING. WEAK SURFACE REFLECTION OF THIS WAVE IS POSITIONED ACROSS SOUTHERN WISCONSIN WITH ITS WARM FRONT EXTENDING SOUTH ACROSS THE ILLINOIS AND INDIANA BORDER. MID-LEVEL BKN-OVC100 CLOUDS HAVE BEEN MOVING ACROSS NORTHWEST LOWER AND EASTERN UPPER WHILE RADARS AND SURFACE OBS FROM SURROUNDING WFOS SHOW SCATTERED SPRINKLES/LIGHT SHOWERS MOVE SOUTHEAST ACROSS NORTHERN WISCONSIN AND CENTRAL LAKE MICHIGAN. MANY OF THESE SHOWERS HAVE NOT BEEN REACHING THE GROUND DUE TO AN EXTREMELY DRY LOW LEVEL AIRMASS IN PLACE WITH A DEWPOINT DEPRESSION NOTED ON THE 12Z APX SOUNDING OF 32C AT 770MB. ALTHOUGH THE LOW LEVELS ARE MORE MOIST AROUND GRB (DEWPOINT DEPRESSIONS OF 10C BLOW 800MB)...THE CONVECTIVE NATURE OF THE PRECIP WITH 700-500MB LAPSE RATES OF 6-6.5 C/KM HAVE ALLOWED SOME OF THESE SHOWERS (AND ISOLATED THUNDERSTORMS) TO REACH THE GROUND OVER WISCONSIN. SHOWER POSSIBILITIES ARE THE MAIN FORECAST CONCERN FOR THE REST OF THE DAY. WILL SEE INCREASING CLOUDS OVER THE REST OF THE DAY WITH THE APPROACHING MID LEVEL WAVE/MOISTURE. MOST OF THE SHOWER ACTIVITY THAT HAS BEEN REACHING THE GROUND HAS BEEN MOVING IN THE SE DIRECTION NOW SE OF GRB WHERE HIGHER 850MB DEWPOINTS/THETA E RESIDES AND SEE NO INDICATION THAT THIS WILL CHANGE THIS AFTERNOON. WILL LEAVE A MENTION OF A SPRINKLE ACROSS NORTHWEST LOWER THROUGH EARLY AFTERNOON TO DEAL WITH THE DIMINISHING SHOWERS CROSSING THE LAKE MICHIGAN ATTM...BUT WILL REMOVE SPRINKLE MENTION ACROSS ALL CWA THEREAFTER AS THE WEDGE OF LOW LEVEL DRY AIR LOOKS TO ABSORB THE VIRGA. SW ZONES MAY RETURN TO PARTLY CLOUDY IF THE MID-LEVEL CLOUDS DISSIPATE BY LATE AFTERNOON OR EARLY EVENING...BUT ADDITIONAL CLOUD COVER ALONG AN 850MB FRONT WEST OF THE WAVE WILL KEEP SKIES ON THE MOSTLY CLOUDY SIDE ESPECIALLY ACROSS EASTERN UPPER AND THE TIP OF THE MIT. MPC && .PREVIOUS DISCUSSION...ISSUED 359 AM EDT TUE APR 17 2007/ OVERALL PATTERN ACROSS NORTH AMERICA WILL BE SOMEWHAT BLOCKY THROUGH THE REMAINDER OF THE WEEK. A SERIES OF SHORT WAVE TROUGHS OVER THE PACIFIC WILL CARVE OUT A MEAN TROUGH ACROSS THE WEST...WHILE REMNANTS OF THE RECENT EAST COAST STORM SYSTEM LEAVE SOME PERSISTENT TROUGHING BEHIND ACROSS THE WESTERN ATLANTIC. RIDGING DEVELOPING BETWEEN THESE FEATURES WILL RESULT IN A BRIEF QUASI-OMEGA BLOCK PATTERN IN THE THURSDAY/FRIDAY TIME FRAME...WITH THE WESTERN GREAT LAKES EVENTUALLY COMING UNDER THE INFLUENCE OF THE UPPER LEVEL RIDGE. IN THE NEAR TERM... HOWEVER...INITIAL FORECAST CONCERNS WILL FOCUS ON A SHORT WAVE TROUGH CROSSING THE NORTHERN PLAINS THIS MORNING AND IMPACTS THIS FEATURE MAY HAVE LATER TODAY. ATTENTION THEN TURNS TO DEEP LAYER MOISTURE ROTATING AROUND REMNANTS OF EAST COAST STORM...AND PRECIPITATION CHANCES/TYPE WITH THIS FOR WEDNESDAY. TODAY/TONIGHT...03Z SURFACE ANALYSIS SHOWED HIGH PRESSURE RIDGE EXTENDING FROM NORTH/SOUTH ACROSS CENTRAL LAKE SUPERIOR/LAKE MICHIGAN/WESTERN IN...WITH A WEAKENING COLD FRONT EXTENDING FROM WESTERN ONTARIO...SOUTHWEST ACROSS NORTHWEST WI/SOUTHEAST MN. ASSOCIATED SHORT WAVE TROUGH WAS SLIDING ACROSS MN AND WESTERN LAKE SUPERIOR PER WV IMAGERY. AREA OF SHOWERS AND SOME THUNDERSTORMS WERE LOCATED AHEAD OF THIS WAVE ACROSS EASTERN MN/NORTHWEST WI/FAR WESTERN UPPER. 00Z MPX SOUNDING EXHIBITED A RATHER DEEP SURFACE BASED MIXED LAYER EXTENDING UP TO 700MB...WITH LAPSE RATES IN THE 700-500MB AT LEAST CONDITIONALLY UNSTABLE... THUS CONTRIBUTING TO UPSTREAM CONVECTIVE DEVELOPMENT. SOUNDINGS AT APX/GRB WERE QUITE DRY (DEW POINT DEPRESSIONS GENERALLY AOA 10C THROUGH 500MB)...AND AS A RESULT SKIES ACROSS NORTHERN MI WERE MAINLY CLEAR EARLY THIS MORNING. EASTWARD PROGRESS OF APPROACHING SHORT WAVE TROUGH EXPECTED TO BE IMPEDED BY CIRCULATION TO THE EAST...WITH MAIN ENERGY EVENTUALLY EXPECTED TO MAKE A TURN SOUTH AND CLOSE OFF A NEW MID LEVEL LOW ACROSS LOWER MI/WI LATER TONIGHT. MID LEVEL MOISTURE ASSOCIATED WITH THIS WAVE WILL SPREAD ACROSS THE FORECAST AREA TODAY... NORTHERLY LOW LEVEL FLOW WILL TRY TO KEEP DRY AIR IN PLACE BELOW 700MB...WHICH SHOULD LIMIT THREAT FOR MEASURABLE PRECIP TODAY BUT COULD AT LEAST SEE SOME SPRINKLES AT LEAST ACROSS MUCH OF NORTHERN LOWER. AS MID LEVEL LOW GETS ORGANIZED DEEP LAYER MOISTURE WILL INCREASE FROM THE EAST/NORTHEAST TONIGHT AS FLOW VEERS MORE FROM THAT DIRECTION. ANTICIPATE THAT THIS WILL RESULT IN AN INCREASE IN PRECIPITATION CHANCES FROM EAST TO WEST OVERNIGHT...VEERING FLOW WILL ALSO PULL COLDER AIR BACK INTO THE STATE TONIGHT. THIS MAY ERODE SURFACE BASED WARM LAYER DEPTH ENOUGH TO ALLOW FOR PRECIP TO MIX WITH OR CHANGE TO SNOW OVERNIGHT...ESPECIALLY IN HIGHER TERRAIN LOCALES WHERE IT IS MORE LIKELY BOUNDARY LAYER WILL COOL ENOUGH TO SUPPORT FROZEN PRECIP. WEDNESDAY...LIGHT PRECIPITATION LOOKS TO BE A PRETTY GOOD BET ON WEDNESDAY...NOT A LOT EXPECTED IN THE QPF DEPARTMENT AS OVERALL FORCING IS WEAK (WEAK ISENTROPIC ASCENT AND DEFORMATION ALONG NORTHERN HALF OF MID LEVEL LOW WHICH WILL BE SINKING INTO THE OHIO RIVER VALLEY. FORECAST SOUNDINGS SUGGEST PRECIP TYPE WILL BE PREDOMINANTLY SNOW WEDNESDAY MORNING...THEN CHANGING TO RAIN ASSUMING BOUNDARY LAYER RESPONDS TO LIMITED INSOLATION THOUGH SOME OF THIS WILL ALSO DEPEND ON HOW COLD TEMPERATURES ACTUALLY GET EARLY WEDNESDAY MORNING. PLAN TO GO PREDOMINANTLY SNOW NORTH OF M-55 WEDNESDAY MORNING...THEN KEEP THE RAIN/SNOW WORDING FOR THE AFTERNOON. WILL ALSO CONTINUE THE RAIN/SNOW MENTION INTO WEDNESDAY NIGHT ACROSS NORTHERN LOWER...SURFACE BASED WARM LAYER DEPTH FORECAST TO INCREASE WHICH WOULD SUPPORT MORE LIQUID PRECIP...BUT TO WHAT DEGREE IS IN DISPUTE AT THIS POINT. NO CHANGES MADE TO THE FORECAST BEYOND WEDNESDAY NIGHT. JPB && .APX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 400 PM CDT TUE APR 17 2007 .AVIATION UPDATE...NEW 18Z GUIDANCE MORE AGGRESSIVE WITH RAIN CHANCES TONIGHT. SATELLITE AND RADAR TRENDS SHOWING LITTLE MORE OF A SE PUSH VS A DUE EAST. HIT THE TAFS A LITTLE HARDER WITH THUNDER THIS EVENING. STILL FEEL SOME PATCHY FOG POSSIBLE TOWARD SUNRISE IF SKIES CLEAR A LITTLE AND GROUND REMAINS WET FROM EVENING RAIN. 43 .DISCUSSION...JUST AS IT LOOKED LIKE THINGS WERE LOOKING RELATIVELY STABLE ACROSS THE CWA THIS AFTERNOON...LAPS SURFACE ANALYSIS INDICATED INSTABILITY INCREASING RAPIDLY ACROSS SOUTHWEST PORTIONS OF NORTH TEXAS. IN ADDITION...SATELLITE IMAGES INDICATE SOME CLEAR SKIES IN THAT AREA THAT HAS ALLOWED TEMPERATURES TO WARM CONSIDERABLY WITH HIGHER DEWPOINTS ADVECTING INTO THE REGION. HOWEVER...THE CAP CONTINUES ACROSS SOUTHEAST TX WITH MOSTLY LIGHT RAIN SHOWERS CONTINUING TO DEVELOP UNDER THE CAP. SPC CONTINUES TO KEEP A SLIGHT RISK OF SEVERE WEATHER FOR EXTREME NORTHERN PORTIONS OF THE CWA...MAINLY FOR HAIL. LATEST RUC AND NAM MODEL RUNS PROG CONVECTION MOVING INTO THE AREA THIS EVENING AS THE 500MB LOW ACROSS NORTHWEST TX MOVES EAST ALLOWING LAPSE RATES TO STEEPEN ACROSS EAST TX...ENOUGH TO RAISE POPS SLIGHTLY AND MENTION SEVERE ACROSS NORTHERN GRIDS/ZONES TONIGHT. WILL NOT MENTION STORMS ALONG THE COASTAL SECTIONS TONIGHT FOR NOW. ONCE THE TROUGH MOVES THROUGH EAST TX TONIGHT...DRY AND WARM WEATHER WILL PREVAIL THROUGH THE REST OF THE WEEK AS A 500MB RIDGE BUILDS OVER THE SOUTHERN PLAINS WEDNESDAY AND AMPLIFIES FRIDAY AS A TROUGH MOVES INTO THE WESTERN UNITED STATES. MOISTURE INCREASES ACROSS THE CWA THROUGH THE WEEKEND AS A PACIFIC FRONTAL SYSTEM DEVELOPS ON THE LEE SIDE OF THE ROCKIES SATURDAY. THIS WARRANTS A MENTION OF RAIN FOR SUNDAY AS A WEAK FRONT MOVES INTO CENTRAL TX AND STALLS. A LARGER 500MB TROUGH IS STILL PROGGED TO DEVELOP ACROSS THE SOUTHWEST U.S. MONDAY AND MOVE EASTWARD INTO WEST TX TUESDAY PROVIDING THE POTENTIAL FOR ANOTHER ROUND OF SEVERE WEATHER AND POSSIBLY HEAVY RAINFALL. WILL HAVE TO MONITOR FUTURE MODEL RUNS TO SEE IF THIS SYSTEM EVOLVES AS PROGGED PER THE 12Z GFS. 32 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 57 76 56 82 60 / 50 0 0 0 0 HOUSTON (IAH) 60 79 57 82 60 / 40 0 0 0 0 GALVESTON (GLS) 65 78 63 76 66 / 30 0 0 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY. SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH WEDNESDAY MORNING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...32 AVIATION/MARINE...43/31 tx AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 351 PM CDT TUE APR 17 2007 .DISCUSSION...JUST AS IT LOOKED LIKE THINGS WERE LOOKING RELATIVELY STABLE ACROSS THE CWA THIS AFTERNOON...LAPS SURFACE ANALYSIS INDICATED INSTABILITY INCREASING RAPIDLY ACROSS SOUTHWEST PORTIONS OF NORTH TEXAS. IN ADDITION...SATELLITE IMAGES INDICATE SOME CLEAR SKIES IN THAT AREA THAT HAS ALLOWED TEMPERATURES TO WARM CONSIDERABLY WITH HIGHER DEWPOINTS ADVECTING INTO THE REGION. HOWEVER...THE CAP CONTINUES ACROSS SOUTHEAST TX WITH MOSTLY LIGHT RAIN SHOWERS CONTINUING TO DEVELOP UNDER THE CAP. SPC CONTINUES TO KEEP A SLIGHT RISK OF SEVERE WEATHER FOR EXTREME NORTHERN PORTIONS OF THE CWA...MAINLY FOR HAIL. LATEST RUC AND NAM MODEL RUNS PROG CONVECTION MOVING INTO THE AREA THIS EVENING AS THE 500MB LOW ACROSS NORTHWEST TX MOVES EAST ALLOWING LAPSE RATES TO STEEPEN ACROSS EAST TX...ENOUGH TO RAISE POPS SLIGHTLY AND MENTION SEVERE ACROSS NORTHERN GRIDS/ZONES TONIGHT. WILL NOT MENTION STORMS ALONG THE COASTAL SECTIONS TONIGHT FOR NOW. ONCE THE TROUGH MOVES THROUGH EAST TX TONIGHT...DRY AND WARM WEATHER WILL PREVAIL THROUGH THE REST OF THE WEEK AS A 500MB RIDGE BUILDS OVER THE SOUTHERN PLAINS WEDNESDAY AND AMPLIFIES FRIDAY AS A TROUGH MOVES INTO THE WESTERN UNITED STATES. MOISTURE INCREASES ACROSS THE CWA THROUGH THE WEEKEND AS A PACIFIC FRONTAL SYSTEM DEVELOPS ON THE LEE SIDE OF THE ROCKIES SATURDAY. THIS WARRANTS A MENTION OF RAIN FOR SUNDAY AS A WEAK FRONT MOVES INTO CENTRAL TX AND STALLS. A LARGER 500MB TROUGH IS STILL PROGGED TO DEVELOP ACROSS THE SOUTHWEST U.S. MONDAY AND MOVE EASTWARD INTO WEST TX TUESDAY PROVIDING THE POTENTIAL FOR ANOTHER ROUND OF SEVERE WEATHER AND POSSIBLY HEAVY RAINFALL. WILL HAVE TO MONITOR FUTURE MODEL RUNS TO SEE IF THIS SYSTEM EVOLVES AS PROGGED PER THE 12Z GFS. 32 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 57 76 56 82 60 / 50 0 0 0 0 HOUSTON (IAH) 60 79 57 82 60 / 40 0 0 0 0 GALVESTON (GLS) 65 78 63 76 66 / 30 0 0 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY. SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH WEDNESDAY MORNING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...32 AVIATION/MARINE...43/31 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 351 PM CDT TUE APR 17 2007 .DISCUSSION...JUST AS IT LOOKED LIKE THINGS WERE LOOKING RELATIVELY STABLE ACROSS THE CWA THIS AFTERNOON...LAPS SURFACE ANALYSIS INDICATED INSTABILITY INCREASING RAPIDLY ACROSS SOUTHWEST PORTIONS OF NORTH TEXAS. IN ADDITION...SATELLITE IMAGES INDICATE SOME CLEAR SKIES IN THAT AREA THAT HAS ALLOWED TEMPERATURES TO WARM CONSIDERABLY WITH HIGHER DEWPOINTS ADVECTING INTO THE REGION. HOWEVER...THE CAP CONTINUES ACROSS SOUTHEAST TX WITH MOSTLY LIGHT RAIN SHOWERS CONTINUING TO DEVELOP UNDER THE CAP. SPC CONTINUES TO KEEP A SLIGHT RISK OF SEVERE WEATHER FOR EXTREME NORTHERN PORTIONS OF THE CWA...MAINLY FOR HAIL. WILL NOT MENTION STORMS ALONG THE COASTAL SECTIONS TONIGHT FOR NOW. LATEST RUC AND NAM MODEL RUNS PROG CONVECTION MOVING INTO THE AREA THIS EVENING AS THE 500MB LOW ACROSS NORTHWEST TX MOVES EAST ALLOWING LAPSE RATES TO STEEPEN ACROSS EAST TX...ENOUGH TO RAISE POPS SLIGHTLY AND MENTION SEVERE ACROSS NORTHERN GRIDS/ZONES TONIGHT. ONCE THE TROUGH MOVES THROUGH EAST TX TONIGHT...DRY AND WARM WEATHER WILL PREVAIL THROUGH THE REST OF THE WEEK AS A 500MB RIDGE BUILDS OVER THE SOUTHERN PLAINS WEDNESDAY AND AMPLIFIES FRIDAY AS A TROUGH MOVES INTO THE WESTERN UNITED STATES. MOISTURE INCREASES ACROSS THE CWA THROUGH THE WEEKEND AS A PACIFIC FRONTAL SYSTEM DEVELOPS ON THE LEE SIDE OF THE ROCKIES SATURDAY. THIS WARRANTS A MENTION OF RAIN FOR SUNDAY AS A WEAK FRONT MOVES INTO CENTRAL TX AND STALLS. A LARGER 500MB TROUGH IS STILL PROGGED TO DEVELOP ACROSS THE SOUTHWEST U.S. MONDAY AND MOVE EASTWARD INTO WEST TX TUESDAY PROVIDING THE POTENTIAL FOR ANOTHER ROUND OF SEVERE WEATHER AND POSSIBLY HEAVY RAINFALL. WILL HAVE TO MONITOR FUTURE MODEL RUNS TO SEE IF THIS SYSTEM EVOLVES AS PROGGED PER THE 12Z GFS. 32 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 57 76 56 82 60 / 50 0 0 0 0 HOUSTON (IAH) 60 79 57 82 60 / 40 0 0 0 0 GALVESTON (GLS) 65 78 63 76 66 / 30 0 0 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY. SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH WEDNESDAY MORNING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...32 AVIATION/MARINE...43/31 tx