Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/06/16


FORECAST DISCUSSION FOR MORE DETAILS.

&& .PREV DISCUSSION...AS OF 3:42 AM PDT WEDNESDAY...IT LOOKS LIKE CLOUD CITY THIS MORNING WITH LOW STRATUS NEAR THE COAST AND PLENTY OF MID AND HIGH CLOUDS STREAMING OVER THE REGION IN ADVANCE OF THE INCOMING UPPER LOW. RADAR SHOWING A FEW HIGH RETURNS OFFSHORE AND OVER THE NORTH BAY...LIKELY VIRGA OR A FEW SPITS OF LIGHT RAIN. LATEST HRRR AND RAP RUNS SUGGEST THE BEST CHANCE FOR ANY SHOWERS TODAY WILL BE OVER THE NORTH BAY AND DURING THE AFTERNOON AS THE LOW GETS CLOSER. MAIN THEME FOR TODAY WILL BE CLOUDY CONDITIONS WITH HIGHS GENERALLY IN THE 60S TO LOWER 70S. UPPER LOW WILL SLOWLY APPROACH THE REGION AND THEN DROP WEST OF THE CENTRAL COAST ON THURSDAY. GRADIENTS ARE LIGHT SO NO STRONG WINDS OF NOTE. CONTINUED CLOUDY WITH SCATTERED SHOWER CHANCES CONTINUING ACROSS THE REGION. AGAIN MOST SHOWERS WILL BE LIGHT AND DUE TO CONVECTIVE NATURE MANY AREAS WILL NOT SEE RAINFALL ON THURSDAY. IN FACT LATEST 06Z NAM SHOWS MOST OF THE SHOWER ACTIVITY FORMING OVER THE HIGHER TERRAIN ON THURSDAY AFTERNOON WHICH IS WHEN WE`LL HAVE A BETTER CHANCE OF SOME ISOLATED T-STORMS AS WELL. THE CORE OF THE UPPER LOW AND COLD AIR ALOFT STAYS OFFSHORE SO LOOKS LIKE WE WONT SEE THE BEST INSTABILITY ON THURSDAY AND IF THE ABUNDANT CLOUD COVER PERSISTS THAT WILL INHIBIT INSTABILITY AS WELL. AS THE UPPER LOW HEADS TOWARDS PT CONCEPTION ON FRIDAY MORNING THE MODELS ARE PAINTING MORE STRATIFORM BUT LIGHT TYPE PRECIP ROTATING AROUND THE UPPER LOW...ESPECIALLY FROM THE BAY AREA SOUTHWARD. GIVEN THE SUBTLE RUN TO RUN CHANGES IT REMAINS DIFFICULT TO PINPOINT EXACTLY WHERE RAIN WILL FALL WITH MANY LOCATIONS LIKELY REMAINING DRY THROUGH THE PERIOD...HOWEVER FRIDAY IS LOOKING LIKE THE DAY THAT MAY NEED THE HIGHEST POPS. 06Z NAM AND GFS RUNS SHOW ANOTHER DEFORMATION BAND ROTATING FROM THE NORTHEAST PART OF THE STATE TOWARDS THE BAY AREA ON SATURDAY KEEPING THE CHANCE OF SHOWERS IN THE FORECAST ALONG WITH THE BELOW NORMAL DAYTIME HIGHS IN THE 60S. SO WE HAVE LEGITIMATE BUT LOW END PRECIP CHANCES THE NEXT FOUR DAYS WITH HIGHER CONFIDENCE FOR BELOW NORMAL TEMPS THE REST OF THE WEEK AND INTO THE WEEKEND. RAIN TOTALS BY SATURDAY COULD EXCEED 0.50 IN SOME OF THE WETTER SPOTS BUT ON AVERAGE TOTALS SHOULD BE MORE AROUND A TENTH OR TWO. SHOWER THREAT SHOULD FINALLY END BY SATURDAY NIGHT FOLLOWED BY A GRADUAL WARMING AND DRYING TREND SUNDAY THROUGH EARLY NEXT WEEK. && .AVIATION...AS OF 11:05 AM PDT WEDNESDAY...UPPER LOW IN VICNITY OF TAF SITES THIS MORNING. THE UPPER CLOUD DECK ASSOCIATED WITH THE COLD FRONTAL BOUNDARY OF THIS FEATURE WILL GRADUALLY SHIFT NORTHEAST AND CLEAR OUT THE UPPER LEVEL CIGS BY MID TO LATE AFTERNOON. THE LOWER CLOUD DECK IS GRADUALLY ATTEMPTING TO PUSH INLAND LATE THIS MORNING IN THE WAKE OF THE FROPA AND AHEAD OF THE TROUGH AXIS AS EVIDENT BY MVFR CIGS RETURNING TO THE MONTEREY BAY REGION. EXPECT THESE LINGERING MVFR CIGS TO EXPERIENCE MIXING WITHIN NEXT FEW HOURS AND CLEAR OUT THROUGH MIDDAY. FORECAST MODELS ARE OF LOW QUALITY FOR THE 18Z TAF PACKAGE HOWEVER ALL SEEM TO INDICATE BORDERLINE MVFR/IFR STRATUS CIGS RETURN BETWEEN 04-10Z THU DEPENDING ON LOCATION. UPPER LOW WILL BRING VCSH THROUGHOUT THE FORECAST DURATION. IN SHORT... VFR CIGS THIS AFTERNOON... MVFR THIS EVENING... AND A FEW SPOTS DROPPING INTO IFR OVERNIGHT. VICINITY OF KSFO...VFR. ONSHORE WINDS UP TO 15KT THIS AFTERNOON. MVFR CIGS RETURN AFTER 04Z. LOW CONFIDENCE ON MVFR RETURN. SFO BRIDGE APPROACH...SIMILAR AS KSFO. MONTEREY BAY TERMINALS...A FEW LINGERING SPOTS OF MVFR THRU 20Z THIS MORN. BRIEF VFR CLEARING MIDDAY. MVFR/IFR CIGS RETURN EVENING/OVERNIGHT. && .MARINE...AS OF 11:00 AM PDT WEDNESDAY...AN UPPER LOW IN THE AREA WILL BRING MODERATE NORTHERLY WINDS IN THE OUTER WATERS NORTH OF PT REYES. LIGHTER SOUTHWEST WINDS WILL PREVAIL SOUTH OF PT REYES. THUNDERSTORMS WILL ALSO BE POSSIBLE DUE TO COLD UNSTABLE AIR. WINDS AND SEAS WILL GRADUALLY INCREASE LATE THIS WEEK. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM SCA...SF BAY FROM 1 PM && $$ PUBLIC FORECAST: RGASS AVIATION: DRP MARINE: DRP VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK AND TWITTER AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
439 AM PDT WED MAY 4 2016 .SYNOPSIS....CLOUDY AND COOL TODAY AS AN UPPER LOW APPROACHES AND PRODUCES SOME NORTH BAY SHOWERS. CHANCE OF SHOWERS CONTINUES OVERNIGHT INTO THURSDAY ALONG WITH A ISOLATED THUNDERSTORMS AS THE UPPER LOW WOBBLES AROUND THE CENTRAL COAST. SHOWER AND ISOLATED THUNDERSTORM THREAT CONTINUES INTO FRIDAY AND LIKELY SATURDAY AS THE SLOW MOVING LOW IMPACTS THE STATE WITH CONTINUED BELOW NORMAL TEMPERATURES. DRYING AND WARMING TREND STARTS SUNDAY AND CONTINUES INTO EARLY NEXT WEEK. && .DISCUSSION...AS OF 3:42 AM PDT WEDNESDAY...IT LOOKS LIKE CLOUD CITY THIS MORNING WITH LOW STRATUS NEAR THE COAST AND PLENTY OF MID AND HIGH CLOUDS STREAMING OVER THE REGION IN ADVANCE OF THE INCOMING UPPER LOW. RADAR SHOWING A FEW HIGH RETURNS OFFSHORE AND OVER THE NORTH BAY...LIKELY VIRGA OR A FEW SPITS OF LIGHT RAIN. LATEST HRRR AND RAP RUNS SUGGEST THE BEST CHANCE FOR ANY SHOWERS TODAY WILL BE OVER THE NORTH BAY AND DURING THE AFTERNOON AS THE LOW GETS CLOSER. MAIN THEME FOR TODAY WILL BE CLOUDY CONDITIONS WITH HIGHS GENERALLY IN THE 60S TO LOWER 70S. UPPER LOW WILL SLOWLY APPROACH THE REGION AND THEN DROP WEST OF THE CENTRAL COAST ON THURSDAY. GRADIENTS ARE LIGHT SO NO STRONG WINDS OF NOTE. CONTINUED CLOUDY WITH SCATTERED SHOWER CHANCES CONTINUING ACROSS THE REGION. AGAIN MOST SHOWERS WILL BE LIGHT AND DUE TO CONVECTIVE NATURE MANY AREAS WILL NOT SEE RAINFALL ON THURSDAY. IN FACT LATEST 06Z NAM SHOWS MOST OF THE SHOWER ACTIVITY FORMING OVER THE HIGHER TERRAIN ON THURSDAY AFTERNOON WHICH IS WHEN WE`LL HAVE A BETTER CHANCE OF SOME ISOLATED T-STORMS AS WELL. THE CORE OF THE UPPER LOW AND COLD AIR ALOFT STAYS OFFSHORE SO LOOKS LIKE WE WONT SEE THE BEST INSTABILITY ON THURSDAY AND IF THE ABUNDANT CLOUD COVER PERSISTS THAT WILL INHIBIT INSTABILITY AS WELL. AS THE UPPER LOW HEADS TOWARDS PT CONCEPTION ON FRIDAY MORNING THE MODELS ARE PAINTING MORE STRATIFORM BUT LIGHT TYPE PRECIP ROTATING AROUND THE UPPER LOW...ESPECIALLY FROM THE BAY AREA SOUTHWARD. GIVEN THE SUBTLE RUN TO RUN CHANGES IT REMAINS DIFFICULT TO PINPOINT EXACTLY WHERE RAIN WILL FALL WITH MANY LOCATIONS LIKELY REMAINING DRY THROUGH THE PERIOD...HOWEVER FRIDAY IS LOOKING LIKE THE DAY THAT MAY NEED THE HIGHEST POPS. 06Z NAM AND GFS RUNS SHOW ANOTHER DEFORMATION BAND ROTATING FROM THE NORTHEAST PART OF THE STATE TOWARDS THE BAY AREA ON SATURDAY KEEPING THE CHANCE OF SHOWERS IN THE FORECAST ALONG WITH THE BELOW NORMAL DAYTIME HIGHS IN THE 60S. SO WE HAVE LEGITIMATE BUT LOW END PRECIP CHANCES THE NEXT FOUR DAYS WITH HIGHER CONFIDENCE FOR BELOW NORMAL TEMPS THE REST OF THE WEEK AND INTO THE WEEKEND. RAIN TOTALS BY SATURDAY COULD EXCEED 0.50 IN SOME OF THE WETTER SPOTS BUT ON AVERAGE TOTALS SHOULD BE MORE AROUND A TENTH OR TWO. SHOWER THREAT SHOULD FINALLY END BY SATURDAY NIGHT FOLLOWED BY A GRADUAL WARMING AND DRYING TREND SUNDAY THROUGH EARLY NEXT WEEK. && .AVIATION...AS OF 4:34 AM PDT WEDNESDAY...TOUGH AND LOW CONFIDENCE FORECAST THIS MORNING AS AN UPPER LEVEL TROUGH OFF THE COAST CREEPS EASTWARD. THE TROUGH IS BRINGING A MIXED BAG OF CIGS THIS MORNING WITH VCSH PASSING THROUGH. CIGS RANGE FROM IFR TO VFR AND ARE VERY TRANSIENT. DO EXPECT ANY CIGS THIS MORNING TO GRADUALLY LIFT AS THE TROUGH APPROACHES. WILL KEEP VCSH FOR THE TAFS GIVEN THE UNCERTAINTY. CIGS RETURN TONIGHT. VICINITY OF KSFO...VFR TO MVFR CIGS THROUGH THIS MORNING. BETTER CHC FOR CIGS OVER THE EAST BAY-KOAK. COVERING SOME PATCHY CIGS AT KSFO WITH A TEMP THIS MORNING. VFR THIS AFTERNOON WITH BREEZY CONDITIONS. SFO BRIDGE APPROACH...SIMILAR AS KSFO. MONTEREY BAY TERMINALS...IFR CIGS THIS MORNING...GRADUALLY LIFTING. VFR THIS AFTERNOON WITH VCSH. && .MARINE...AS OF 03:20 AM PDT WEDNESDAY...AN APPROACHING STORM SYSTEM WILL BRING UNSETTLED WEATHER TO THE REGION INTO THE WEEKEND. THUNDERSTORMS WILL ALSO BE POSSIBLE DUE TO COLD UNSTABLE AIR. WINDS AND SEAS WILL GRADUALLY INCREASE LATE THIS WEEK. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM SCA...SF BAY FROM 1 PM && $$ PUBLIC FORECAST: R_WALBRUN AVIATION: MM MARINE: MM VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK AND TWITTER AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
343 AM PDT WED MAY 4 2016 .SYNOPSIS....CLOUDY AND COOL TODAY AS AN UPPER LOW APPROACHES AND PRODUCES SOME NORTH BAY SHOWERS. CHANCE OF SHOWERS CONTINUES OVERNIGHT INTO THURSDAY ALONG WITH A ISOLATED THUNDERSTORMS AS THE UPPER LOW WOBBLES AROUND THE CENTRAL COAST. SHOWER AND ISOLATED THUNDERSTORM THREAT CONTINUES INTO FRIDAY AND LIKELY SATURDAY AS THE SLOW MOVING LOW IMPACTS THE STATE WITH CONTINUED BELOW NORMAL TEMPERATURES. DRYING AND WARMING TREND STARTS SUNDAY AND CONTINUES INTO EARLY NEXT WEEK. && .DISCUSSION...AS OF 3:42 AM PDT WEDNESDAY...IT LOOKS LIKE CLOUD CITY THIS MORNING WITH LOW STRATUS NEAR THE COAST AND PLENTY OF MID AND HIGH CLOUDS STREAMING OVER THE REGION IN ADVANCE OF THE INCOMING UPPER LOW. RADAR SHOWING A FEW HIGH RETURNS OFFSHORE AND OVER THE NORTH BAY...LIKELY VIRGA OR A FEW SPITS OF LIGHT RAIN. LATEST HRRR AND RAP RUNS SUGGEST THE BEST CHANCE FOR ANY SHOWERS TODAY WILL BE OVER THE NORTH BAY AND DURING THE AFTERNOON AS THE LOW GETS CLOSER. MAIN THEME FOR TODAY WILL BE CLOUDY CONDITIONS WITH HIGHS GENERALLY IN THE 60S TO LOWER 70S. UPPER LOW WILL SLOWLY APPROACH THE REGION AND THEN DROP WEST OF THE CENTRAL COAST ON THURSDAY. GRADIENTS ARE LIGHT SO NO STRONG WINDS OF NOTE. CONTINUED CLOUDY WITH SCATTERED SHOWER CHANCES CONTINUING ACROSS THE REGION. AGAIN MOST SHOWERS WILL BE LIGHT AND DUE TO CONVECTIVE NATURE MANY AREAS WILL NOT SEE RAINFALL ON THURSDAY. IN FACT LATEST 06Z NAM SHOWS MOST OF THE SHOWER ACTIVITY FORMING OVER THE HIGHER TERRAIN ON THURSDAY AFTERNOON WHICH IS WHEN WE`LL HAVE A BETTER CHANCE OF SOME ISOLATED T-STORMS AS WELL. THE CORE OF THE UPPER LOW AND COLD AIR ALOFT STAYS OFFSHORE SO LOOKS LIKE WE WONT SEE THE BEST INSTABILITY ON THURSDAY AND IF THE ABUNDANT CLOUD COVER PERSISTS THAT WILL INHIBIT INSTABILITY AS WELL. AS THE UPPER LOW HEADS TOWARDS PT CONCEPTION ON FRIDAY MORNING THE MODELS ARE PAINTING MORE STRATIFORM BUT LIGHT TYPE PRECIP ROTATING AROUND THE UPPER LOW...ESPECIALLY FROM THE BAY AREA SOUTHWARD. GIVEN THE SUBTLE RUN TO RUN CHANGES IT REMAINS DIFFICULT TO PINPOINT EXACTLY WHERE RAIN WILL FALL WITH MANY LOCATIONS LIKELY REMAINING DRY THROUGH THE PERIOD...HOWEVER FRIDAY IS LOOKING LIKE THE DAY THAT MAY NEED THE HIGHEST POPS. 06Z NAM AND GFS RUNS SHOW ANOTHER DEFORMATION BAND ROTATING FROM THE NORTHEAST PART OF THE STATE TOWARDS THE BAY AREA ON SATURDAY KEEPING THE CHANCE OF SHOWERS IN THE FORECAST ALONG WITH THE BELOW NORMAL DAYTIME HIGHS IN THE 60S. SO WE HAVE LEGITIMATE BUT LOW END PRECIP CHANCES THE NEXT FOUR DAYS WITH HIGHER CONFIDENCE FOR BELOW NORMAL TEMPS THE REST OF THE WEEK AND INTO THE WEEKEND. RAIN TOTALS BY SATURDAY COULD EXCEED 0.50 IN SOME OF THE WETTER SPOTS BUT ON AVERAGE TOTALS SHOULD BE MORE AROUND A TENTH OR TWO. SHOWER THREAT SHOULD FINALLY END BY SATURDAY NIGHT FOLLOWED BY A GRADUAL WARMING AND DRYING TREND SUNDAY THROUGH EARLY NEXT WEEK. && .AVIATION...AS OF 10:54 PM PDT TUESDAY...THE SOUTHERN END OF AN ELONGATED UPPER LEVEL TROUGH OVER THE EASTERN PACIFIC WILL GRADUALLY MOVE EAST AND BECOME A CLOSED LOW WEDNESDAY. SATELLITE SHOWS AREAS OF LOW CLOUDS MOSTLY OVER THE COASTAL WATERS WHILE MID-HIGH LEVEL CLOUDS CONTINUE TO STREAM IN OFF THE EASTERN PACIFIC. MARINE LAYER INVERSIONS ARE LIKELY TO STEADILY DEEPEN AND WEAKEN TONIGHT AND WEDNESDAY AS DEEP LAYERED COOLING TAKES PLACE IN THE ATMOSPHERE DUE TO THE APPROACHING EPAC TROUGH. THE WINDS FORECAST IS LOW CONFIDENCE THIS PERIOD. CIGS FORECAST LOW TO MODERATE CONFIDENCE TONIGHT AND WEDNESDAY. VICINITY OF KSFO...VFR TO MVFR CIGS LATE TONIGHT AND WEDNESDAY MORNING. VICINITY SHOWERS AFTER 17Z WEDNESDAY. SFO BRIDGE APPROACH...SIMILAR AS KSFO. MONTEREY BAY TERMINALS...MVFR CIGS GRADUALLY DEVELOPING THIS EVENING. LOW CONFIDENCE IFR CIGS FORECAST TONIGHT. PARTIAL CLEARING RETURNS BY LATE WEDNESDAY MORNING. VICINITY SHOWERS WEDNESDAY AFTERNOON. && .MARINE...AS OF 03:20 AM PDT WEDNESDAY...AN APPROACHING STORM SYSTEM WILL BRING UNSETTLED WEATHER TO THE REGION INTO THE WEEKEND. THUNDERSTORMS WILL ALSO BE POSSIBLE DUE TO COLD UNSTABLE AIR. WINDS AND SEAS WILL GRADUALLY INCREASE LATE THIS WEEK. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM SCA...SF BAY FROM 1 PM && $$ PUBLIC FORECAST: R_WALBRUN AVIATION: MM MARINE: MM VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK AND TWITTER AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
954 AM EDT WED MAY 4 2016 .SYNOPSIS... LOW PRESSURE WILL CONSOLIDATE OFFSHORE THROUGH THURSDAY BEFORE MOVING NORTHEASTWARD. MEANWHILE, ANOTHER LOW PRESSURE SYSTEM DEVELOPS OFF THE MID ATLANTIC COAST THURSDAY NIGHT AND FRIDAY AND THEN MOVES NORTHEASTWARD THROUGH SATURDAY. A COLD FRONT IS FORECAST TO MOVE THROUGH SUNDAY MORNING FOLLOWED BY HIGH PRESSURE BUILDING IN FOR MONDAY AND TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WE HAVE MADE SOME MINOR ADJUSTMENTS TO THE PREVIOUS FORECAST. AN AREA OF SHOWERS DEVELOPING OVER OUR SOUTHERN COUNTIES AT MID MORNING WILL INCREASE IN COVERAGE AS IT ADVECTS TO THE NORTH. IT SHOULD IMPACT THE REMAINDER OF OUR FORECAST AREA DURING THE BALANCE OF THE MORNING AND INTO THE EARLY TO MID AFTERNOON. THE LATEST HRRR SEEMS TO BE HANDLING THE OVERALL TREND WELL. OTHERWISE, LOW CLOUDS WILL PERSIST THROUGH THE DAY ALONG WITH FOG IN THE ELEVATED TERRAIN. TEMPERATURES WILL REMAIN BELOW NORMAL IN THE NORTHEASTERLY FLOW. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... PWAT DRIES TO 0.75 INCHES AND INSTABILITY ALOFT DECREASES BUT A CONTD MOIST CYCLONIC CIRCULATION WITH PROBABLY PERIODS OF MEASURABLE DRIZZLE AND MAYBE A FEW POCKETS OF SHOWERS. 50 50 BLENDED 00Z/4 GFS NAM GUIDANCE. WE SEE THE SPC WRF DRIES US OUT CONSIDERABLY TONIGHT SO POPS ARE GENERALLY 60 PCT N AND 30-40 PCT SOUTH. BEST CHANCE FOR MEASURABLE MAY BE PRIOR TO MIDNIGHT. NE WIND GUSTY NEAR 15 MPH... EXPECT 20-25 MPH MONMOUTH COUNTY COAST. && .LONG TERM /THURSDAY THROUGH TUESDAY/... THE SYNOPTIC SETUP IS COMPRISED OF AN OMEGA BLOCK, THEN THIS PATTERN IS FORECAST TO BREAK DOWN SOME DURING THE SECOND HALF OF THE WEEKEND AND ESPECIALLY EARLY NEXT WEEK. A FEW WEEKS AGO THERE WAS AN OMEGA BLOCK IN PLACE, HOWEVER AT THAT TIME WE WERE UNDER THE RIDGE. THIS GO AROUND WE ARE UNDER THE TROUGH PART OF THE BLOCK, KEEPING OUR WEATHER COOLER AND UNSETTLED. THE REST OF THE WEEK WILL THEREFORE BE UNSETTLED WITH SOME IMPROVEMENT DURING THE WEEKEND, THEN A MORE NOTABLE IMPROVEMENT ANTICIPATED FOR EARLY NEXT WEEK. WE USED A MODEL BLEND APPROACH FOR THURSDAY INTO SATURDAY, THEN BLENDED IN THE 00Z WPC GUIDANCE THEREAFTER. SOME ADJUSTMENTS WERE THEN MADE FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES. FOR THURSDAY AND FRIDAY...THE OMEGA BLOCK CONTINUES WITH A STRONG SHORT WAVE CLOSING OFF THE TROUGH AS IT TRACKS FROM THE OHIO VALLEY AND ACROSS THE SOUTHEASTERN STATES THURSDAY. SOME SHORT WAVE ENERGY TRACKING NORTHWARD ON THE EAST SIDE OF THE LARGE TROUGH WILL TEAM UP WITH ISENTROPIC LIFT ABOVE A MARINE LAYER AND PRODUCE SOME SHOWERS. THURSDAY MORNING HOWEVER COULD ALSO START WITH SOME DRIZZLE. THE ENTIRE TROUGH AND CLOSED LOW ARE FORECAST TO BECOME CENTERED ALONG THE EAST COAST FRIDAY WITH THE CLOSED LOW ITSELF MOVING OVER OUR CWA DURING FRIDAY. THIS WILL DRIVE LOW PRESSURE OFF THE MID ATLANTIC COAST NORTHWARD ALTHOUGH IT LOOKS TO NOT DEEPEN CONSIDERABLY. AS THIS OCCURS, THE 500 MB TEMPERATURES ARE FORECAST TO COOL TO NEAR -24C ON FRIDAY. THIS WOULD PROMOTE SOME INSTABILITY AND PERHAPS SOME LOW-TOPPED CONVECTION, HOWEVER CLOUD COVER AND NUMEROUS SHOWERS MAY TEMPER THIS POTENTIAL. OTHERWISE, AN EASTERLY LOW-LEVEL JET DEVELOPS FRIDAY ACROSS OUR NORTHEASTERN ZONES THEN THIS PIVOTS NORTH-NORTHWESTWARD DURING THE AFTERNOON. SOME GUIDANCE IS STRONGER WITH THIS FEATURE WHICH ALSO DRIVES A BAND OF STRONGER 700-800 MB FRONTOGENETIC FORCING. OVERALL, THERE LOOKS LIKE DECENT LIFT ON THE NOSE OF THE EASTERLY JET TO PROMOTE AN AREA OF SHOWERS/RAIN THAT PIVOTS INLAND DURING FRIDAY. WE MAY NOT SEE ANY BREAKS IN THE CLOUDS, BUT IF THERE ARE THEN ANY LOW- TOPPED CONVECTION COULD PRODUCE SMALL HAIL GIVEN THE VERY COLD 500 MB TEMPERATURES. AS OF NOW HOWEVER, ANY INSTABILITY LOOKS MEAGER. THE SYSTEM THEM MEANDERS OVER OUR AREA FRIDAY NIGHT AND WHILE THERE SHOULD BE A DECREASE IN THE SHOWER COVERAGE SOME SHOULD LINGER THROUGH THE NIGHT. FOR SATURDAY AND SUNDAY...THERE HAS BEEN A GENERAL SLOWING TREND IN THE GUIDANCE WHEN COMPARING THE MANY MODELS AND ENSEMBLES. THIS TENDS TO HAPPEN WITH BLOCKING PATTERNS AS IT TAKES LONGER FOR THE CLOSED LOW TO OPEN UP AND LIFT OUT. THERE ARE CONSIDERABLE DIFFERENCES AT THE SURFACE ON SATURDAY WHICH LEADS TO PLENTY OF DETAIL UNCERTAINTIES INCLUDING THE AMOUNT OF RAIN. WE THEREFORE LEANED CLOSER TO THE WPC GUIDANCE BUT ALSO INCORPORATING SOME CONTINUITY. THIS MEANS THAT SATURDAY LOOKS TO BE STILL UNSETTLED WITH SOME SHOWERS STILL HANGING AROUND. THE AMOUNT OF SHOWER ACTIVITY WILL DEPEND ON THE SHORT WAVE FORCING AROUND THE CLOSED LOW, HOWEVER PLENTY OF COLD AIR REMAINS ALOFT WHICH WILL HELP WITH SOME INSTABILITY. THIS SYSTEM SHOULD OPEN UP AND START SHIFTING EAST SATURDAY NIGHT AS UPSTREAM ENERGY IN THE FORM OF A TROUGH SLIDES SOUTHEASTWARD FROM THE GREAT LAKES. THIS DRIVES A COLD FRONT ACROSS OUR AREA MOSTLY SUNDAY MORNING WITH PERHAPS SOME SHOWERS. THE AIR ALOFT MODIFIES SOME THROUGH THE WEEKEND, THEREFORE MODERATING DAYTIME TEMPERATURES SHOULD RESULT ESPECIALLY ON SUNDAY. FOR MONDAY AND TUESDAY...WE TRANSITION OUT OF AN OMEGA BLOCK DURING THIS TIME FRAME, RESULTING IN WARMER TEMPERATURES. SOME GUIDANCE HOWEVER HAS A SHORT WAVE AMPLIFYING A TROUGH ACROSS THE NORTHEAST MONDAY BEFORE SHIFTING EAST TUESDAY AS A RIDGE APPROACHES FROM THE WEST. IT APPEARS THAT HIGH PRESSURE BUILDS IN WITH TIME, HOWEVER ENERGY IN THE PLAINS WILL SEND A DEVELOPING WARM FRONT TO OUR SOUTH TOWARD OUR AREA TUESDAY. WE KEPT THE FORECAST DRY ATTM WITH MUCH WARMER AIR BUILDING INTO THE AREA. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...GENERALLY IFR CIGS WITH PATCHY 2-5 MI IN PERIODS OF SHOWERS. TIMING OF THE RAIN MAINLY LATE MORNING TO MID AFTERNOON. ISOLATED THUNDER NOT IMPOSSIBLE PER NAM/GFS INSTABILITY ALOFT, MAINLY DELMARVA OR SE PA/S NJ. NE WIND WITH A FEW GUSTS 15-20 KT VCNTY KPHL/KACY. TONIGHT...GENERALLY IFR CIGS WITH PATCHY 2-5 MI IN SCT SHOWERS DIMINISHING OR ENDING-EXITING NEWD EARLY/PATCHY DRIZZLE-FOG IN THE WAKE OF THE NEWD SHOWER DEPARTURE. POSSIBLE LIFR CIGS. NE WIND G 15-20 KT POSSIBLE KPHL- KTTN- KACY. OUTLOOK... THURSDAY AND FRIDAY...MVFR/IFR CEILINGS PERSIST WITH AN ONSHORE FLOW AND WEAK LOW PRESSURE NEAR THE COAST. TIMES OF SHOWERS ARE EXPECTED AS WELL WITH THE MOST WIDESPREAD ACTIVITY OCCURRING ON FRIDAY. NORTHEAST WINDS MAINLY IN THE 10-15 KNOT RANGE /LESS AT NIGHT/ WITH THE HIGHER SPEEDS MAINLY CLOSER TO THE COAST. SATURDAY AND SUNDAY...MVFR/IFR CEILINGS POSSIBLE TO START SATURDAY, THEN IMPROVEMENTS TO VFR SHOULD OCCUR. SOME SHOWERS ARE POSSIBLE AS ONE SYSTEM DEPARTS ON SATURDAY, THEN A COLD FRONT MOVES THROUGH MAINLY SUNDAY MORNING. THE WINDS SHIFT TO THE NORTHWEST SATURDAY THEN LIGHT SOUTHWEST AT NIGHT, BEFORE SHIFTING TO THE NORTHWEST AND INCREASING TO 10-15 KNOTS DURING SUNDAY. && .MARINE... SCA WITH WIND NNJ AND SCA SNJ. DID NOT ATTM ADD SCA FOR DE COAST SINCE 44009 ON THE OUTER EDGE OF 455 IS MARGINALLY 5 FT. HOWEVER, AM NOW ANTICIPATING WE`LL NEED AN SCA IN THE DE ATLC WATERS FOR LATER TONIGHT. SST`S ARE NEAR OR SLIGHTLY ABOVE NORMAL. OUTLOOK... THURSDAY AND FRIDAY...A PERSISTENT ONSHORE FLOW WILL INCREASE FOR A TIME THURSDAY AS ONE LOW PRESSURE SYSTEM TO OUR SOUTH TRACKS NORTHEASTWARD. THIS SHOULD RESULT IN WIND GUSTS TO AROUND 25 KNOTS MAINLY ACROSS THE NORTHERN ATLANTIC COASTAL WATERS THURSDAY. A SECONDARY LOW PRESSURE SYSTEM ARRIVES DURING FRIDAY WITH A POSSIBLE 25-30 KNOT NORTHEASTERLY SURGE ACROSS OUR NORTHERN ATLANTIC COASTAL WATERS. THIS WILL DEPEND ON THE STRENGTH OF AN EASTERLY LOW-LEVEL JET THAT LIFTS NORTHWARD FRIDAY. THE SEAS ARE FORECAST TO BE 4-6 FEET MOSTLY FOR THE NEW JERSEY ATLANTIC COASTAL WATERS, AND THE SMALL CRAFT ADVISORY WAS EXTENDED THROUGH 22Z THURSDAY. THIS WILL LIKELY NEED TO BE EXTENDED AGAIN, AND SEAS MAY BUILD TO 5 FEET FARTHER SOUTH THROUGH FRIDAY AND THEREFORE THE ADVISORY MAY NEED TO BE EXPANDED SOUTHWARD. SATURDAY AND SUNDAY...A COLD FRONT ARRIVES SUNDAY MORNING WITH THE WINDS TURNING SOUTHWEST AHEAD OF IT LATE SATURDAY THEN SHIFTING TO THE NORTHWEST ON SUNDAY. THE WINDS ARE FORECAST TO INCREASE SUNDAY BEHIND THE FRONTAL PASSAGE, HOWEVER IT APPEARS THAT SPEEDS ARE BELOW ADVISORY CRITERIA. THE SEAS SHOULD ALSO BE DROPPING BELOW 5 FEET WITH SOME HELP ON SUNDAY DUE TO THE FLOW INCREASING FROM OFFSHORE. && .TIDES/COASTAL FLOODING... CF ADVISORY ISSUED. GUIDANCE SUGGESTIONS OF INCREASED POSITIVE DEPARTURES COMBINED WITH INCREASING ASTRONOMICAL EVENING TIDES, LOWERING PRESSURE AND AN INCREASING ONSHORE WIND FAVORED AN ADVISORY ISSUANCE. IT WILL BE MARGINAL...PROBABLY PLUS OR MINUS .2 FT FROM THRESHOLD. THIS MORNINGS HIGH TIDE, ESPECIALLY NEAR LEWES WAS .3FT HIGHER THAN LAST EVENINGS. THAT UPWARD DEPARTURE TREND SHOULD CONTINUE THE NEXT SEVERAL CYCLES. THE LONG DURATION NORTHEASTERLY FETCH COMBINED WITH A DAILY INCREASE IN ASTRONOMICAL TIDES AS WE APPROACH THE NEW MOON FRIDAY WILL RESULT IN PERIODS OF MINOR EVENING COASTAL FLOODING. ALL AVAILABLE GUIDANCE SUGGESTS THERE COULD/SHOULD BE SOME MINOR TIDAL FLOODING AROUND THE TIMES OF HIGH TIDE THIS EVENING, THURSDAY EVENING, AND MORE LIKELY FRIDAY EVENING. FOR NOW, ISSUED A COASTAL FLOOD ADVISORY FOR THE NJ/DE COASTS AND DELAWARE BAY FOR THIS EVENINGS HIGH TIDE. THERE IS ALSO A SLIGHT CHANCE OF REACHING A MODERATE THRESHOLD FRIDAY EVENING, BUT CONFIDENCE IS LOW. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...COASTAL FLOOD ADVISORY FROM 5 PM THIS AFTERNOON TO 11 PM EDT THIS EVENING FOR NJZ012>014-020>027. DE...COASTAL FLOOD ADVISORY FROM 5 PM THIS AFTERNOON TO 11 PM EDT THIS EVENING FOR DEZ002>004. MD...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT THURSDAY FOR ANZ452-453. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR ANZ450-451. && $$ SYNOPSIS...GORSE NEAR TERM...DRAG/IOVINO SHORT TERM...DRAG LONG TERM...GORSE AVIATION...DRAG/GORSE MARINE...DRAG/GORSE TIDES/COASTAL FLOODING...STAFF
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1002 AM EDT WED MAY 4 2016 .SYNOPSIS... ISSUED AT 1002 AM EDT WED MAY 4 2016 SHOWERS WILL BE POSSIBLE THROUGH TONIGHT AS A LOW PRESSURE SYSTEM MOVES ACROSS THE AREA. WARMER AND DRIER WEATHER CAN BE EXPECTED FRIDAY WITH HIGHS IN THE 70S. && .UPDATE... ISSUED AT 1002 AM EDT WED MAY 4 2016 MADE SOME SIGNIFICANT CUTS TO EARLY AFTERNOON POPS FOR THE MORNING UPDATE. LATEST HRRR AND RAP...SUPPORTED BY WATER VAPOR AND RADAR MOSAIC...INDICATE A PERIOD OF PRIMARILY DRY CONDITIONS IN THE WAKE OF PASSING COLD FRONT. PIVOTING DEFORMATION AXIS APPEARS TO REMAIN OVER MICHIGAN UNTIL LATE AFTERNOON...AT WHICH POINT IT WILL SWING SOUTHEAST AND BRING ANOTHER ROUND OF LIGHT RAIN SHOWERS TO OUR AREA THIS EVENING/OVERNIGHT FROM NW TO SE. ALSO REMOVED THUNDER MENTION. WOULDN`T RULE OUT AN ISOLATED LIGHTNING STRIKE IN OUR FAR EAST BUT NOTHING OBSERVED SO FAR AND COLDER AIR IS PUSHING RAPIDLY SOUTHEAST BEHIND THE FRONT...FURTHER LIMITING ALREADY PALTRY INSTABILITY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 230 AM EDT WED MAY 4 2016 WATER VAPOR IMAGERY DEPICTING DEEP UPPER TROF OVER THE NORTHERN GREAT LAKES REGION WITH POTENT SHORT WAVE ENERGY APPROACHING THE BASE OF THE TROF. THIS IS COMBINING WITH STRONG MASS CONVERGENCE ALONG ASSOCIATED SURFACE COLD FRONT TO GENERATE AREA OF SHOWERS AND THUNDERSTORMS ACROSS SOUTHERN WISCONSIN MOVING INTO NORTHERN ILLINOIS TONIGHT. UPPER TROF WILL DIG SOUTH AND CLOSE OFF OVER SOUTHERN GREAT LAKES BY MIDDAY TODAY...BRINGING 100M HEIGHT FALLS AND -26C COLD POOL OVER THE AREA WHICH WILL CONTINUE TO SUPPORT SHOWERS AND THUNDERSTORMS AHEAD OF COLD FRONT THAT WILL SWEEP ACROSS THE AREA TODAY. EXPECT NON-DIURNAL EARLY MORNING HIGH TEMP IN WESTERN CWA WITH ARRIVAL OF COLD FRONT AROUND 12Z THIS MORNING AND STRONG CAA ON GUSTY NW WINDS BEHIND FRONT WILL HAVE TEMPS STEADY/SLOWLY FALLING DURING THE DAY. PRECIP LINGERS INTO WEDNESDAY NIGHT AS MOISTURE WRAPS AROUND CYCLONIC FLOW WITH UPPER LOW DROPPING SOUTHEAST INTO OHIO VALLEY. && .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 230 AM EDT WED MAY 4 2016 GRADUALLY IMPROVING CONDITIONS TO BEGIN ON THURSDAY AS INFLUENCE OF UPPER LOW WANES AS IT CONTINUES SOUTHEAST TOWARD THE MID ATLANTIC. RIDGING...SURFACE AND ALOFT WILL BUILD IN FROM THE WEST AND LEAD TO GRADUALLY CLEARING SKIES OVER THE WESTERN CWA BY THURSDAY AFTERNOON. FAIR WEATHER WILL CONTINUE ON FRIDAY AS TEMPS WARM BACK INTO THE 70S. NORTHERN STREAM SYSTEM MOVING ACROSS SOUTHERN CANADA WILL DRAG A WEAK SURFACE COLD FRONT THROUGH THE AREA ON SATURDAY. UPPER SUPPORT REMAINS DETACHED TO THE NORTH AND LOW LEVEL FORCING WEAKENS AS FRONT TAKES ON EAST/WEST ORIENTATION AS IT MOVES THROUGH. FRONT WILL ALSO BE LACKING IN MOISTURE AS SURFACE HIGH PRESSURE WILL BE ANCHORED OVER GULF OF MEXICO. THEREFORE LOW CONFIDENCE IN PRECIP DEVELOPING AND WILL CUT POPS FROM SUPERBLEND TO SMALL CHANCE. FOCUS THEN SHIFTS TO UPPER LOW THAT WILL BE LIFTING OUT OF THE FOUR CORNERS ON SUNDAY. DOWNSTREAM RIDGING RESULTING FROM THIS SYSTEM WILL HAVE OUR AREA DRY SUNDAY AND MONDAY. MEDIUM RANGE MODELS OFFERING VARYING SOLNS HANDLING UPPER LOW BUT AGREEMENT CAN BE FOUND WITH A SLOWER TREND FOR BRINGING PRECIP BACK INTO THE AREA...AND THIS IS REFLECTED IN SUPERBLEND POPS AS WELL WITH ONLY SLIGHT CHANCE UNTIL TUESDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 649 AM EDT WED MAY 4 2016 AN UPPER LEVEL TROF WILL MOVE SOUTH ACROSS THE MIDWEST TODAY. AHEAD OF THIS SYSTEM...A COLD FRONT WILL MOVE ACROSS NORTHERN INDIANA AND BE ACCOMPANIED BY SHOWERS AND LOWER CEILINGS. VERY LIMITED MID LEVEL INSTABILITY SHOULD LIMIT STORM DEVELOPMENT. HAVE KEPT THUNDER OUT OF TAFS FOR NOW...ALTHOUGH AN ISOLATED STORM IS POSSIBLE. AN UPPER LEVEL LOW WILL DRIFT SOUTH OVER THE AREA LATER TODAY BEHIND THE FRONT AND SHOULD KEEP CONDITIONS IFR OR LOW MVFR/CIGS 008 TO 012. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY FROM 5 AM TO 5 PM EDT THURSDAY FOR LMZ043- 046. GALE WARNING UNTIL 5 AM EDT THURSDAY FOR LMZ043-046. && $$ UPDATE...AGD SYNOPSIS...SKIPPER/AGD SHORT TERM...JAL LONG TERM...JAL AVIATION...SKIPPER VISIT US AT WWW.WEATHER.GOV/IWX FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
617 PM CDT THU MAY 5 2016 ...AVIATION UPDATE... .SYNOPSIS... ISSUED AT 315 PM CDT THU MAY 5 2016 HIGH PRESSURE RIDGE OVER THE CWA PROVIDING FULL SUNSHINE...LIGHT WINDS AND PLEASANT SPRING TEMPERATURES. 2 PM READINGS WERE IN THE UPPER 50S TO LOWER 60S. WEAK CONVERGENCE IN THE MID LEVELS HAS CAUSED A BAND OF MID LEVEL CLOUDS MUCH OF THE DAY FROM EASTERN MN INTO CENTRAL IA AND NORTH CENTRAL MO. THIS HAS PRETTY MUCH STAYED JUST WEST OF THE DVN CWA AS THE CLOUDS DRIFT SOUTHWARD. THERE HAS EVEN BEEN A FEW LIGHT SHOWERS REACHING THE GROUND IN FAR WESTERN WI AND THE EAST METRO OF THE TWIN CITIES. THESE SHOWERS WERE OCCURRING IN THE STRONGER ZONE OF WARM AIR ADVECTION. ELSEWHERE...TEMPERATURES WERE IN THE UPPER 70S TO MID 80S IN THE GREAT PLAINS...WITH SOME LOWER 90S IN ND AND MANITOBA. RELATIVE HUMIDITY THERE WAS 15 PERCENT WITH SOUTHWEST WINDS GUSTING OVER 30 MPH. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 315 PM CDT THU MAY 5 2016 MUCH WARMER TEMPERATURES IN THE SHORT TERM. TONIGHT...HIGH PRESSURE RIDGE WILL BE PUSHING SOUTH OF THE AREA ALLOWING FOR WARMER TEMPERATURES AS WINDS BECOMING LIGHT SOUTHWEST. LOWS WILL BE ABOUT 10 DEGREES WARMER THAN LAST NIGHT...IN THE UPPER 40S. SCATTERED MID LEVEL CLOUDS SHOULD DEVELOP OVERNIGHT BUT EXPECTING ANY SHOWERS TO REMAIN IN WISCONSIN WHERE THE BETTER WARM AIR ADVECTION WILL EXIST. BELIEVE THE HRRR IS OVERDOING THE SHOWERS IN THE DVN CWA BUT CAN`T RULE OUT A COUPLE OF SPRINKLES. WON`T MENTION IN THE GRIDS BUT SOMETHING FOR LATER SHIFTS TO MONITOR. FRIDAY...WARM DAY WITH THE RETURN FLOW AROUND THE HIGH PRESSURE SYSTEM DROPPING INTO THE LOWER MS VALLEY. A WEST TO SOUTHWEST WIND...850 MB TEMPERATURES OF +15 TO 16C AND A DRY AIRMASS SHOULD SUPPORT LOWER 80S AT MOST LOCATIONS. IT IS POSSIBLE A FEW SPOTS MAY MANAGE TO SEE 85 DEGREES CONSIDERING WE SHOULD HAVE SUNNY SKIES. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 315 PM CDT THU MAY 5 2016 SATURDAY...EASTWARD PROGRESSION OF THE 500MB RIDGE AXIS WILL BE HALTED BY A SHORTWAVE TROUGH DIVING SOUTHEASTWARD THROUGH THE UPPER MIDWEST AND GREAT LAKES. SIGNIFICANT HEIGHT FALLS ASSOCIATED WITH THIS SYSTEM ARE FORECAST TO REMAIN OVER WISCONSIN AND MICHIGAN AND POINTS TO THE E/NE. AS A RESULT...LIFT OVER E IOWA/W ILLINOIS WILL BE WEAK AND PRIMARILY RESTRICTED TO LOW-LEVEL CONVERGENCE ALONG A SOUTHWARD MOVING COLD FRONT. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG AND SLIGHTLY AHEAD OF THE FRONT...POPS ARE IN THE 30-40 PERCENT RANGE WITH RAIN AMOUNTS LESS THAN A TENTH FOR MOST AREAS. THE FRONT IS FORECAST TO REACH THE SOUTHERN CWA BY THE MID TO LATE AFTN. THUNDERSTORM DETAILS...THE BEST CHANCES FOR A FEW STRONG STORMS IN THE DVN CWA ARE IN THE COUNTIES ALONG AND SOUTH OF HIGHWAY 34...TO THE WEST OF GALESBURG...WHERE MUCAPES MAY EXCEED 1500 J/KG AND 0-6 KM BULK SHEAR IS NEAR 45 KTS OR SLIGHTLY HIGHER. SUNDAY THROUGH TUESDAY...SATURDAY/S COLD FRONT WILL BECOME QUASI- STATIONARY SATURDAY NIGHT AND RETURN AS A WARM FRONT SUNDAY AND MONDAY AS IT IS FORCED BY A NEW AREA OF LOW PRESSURE FORMING IN THE WEST-CENTRAL PLAINS. SHOWER AND THUNDERSTORM CHANCES ARE HIGHEST FROM SUNDAY NIGHT INTO TUESDAY. GFS 850MB WV TRANSPORT IS MAXIMIZED ON MONDAY AND MONDAY NIGHT AS PWATS INCREASE TO 1.25 INCHES TO THE ESE OF A COHERENT 850MB LOW MOVING INTO E NEBRASKA. RAIN POTENTIAL...THE THREAT FOR WIDESPREAD HEAVY RAIN WITH THIS LOW PRESSURE SYSTEM HIGHLIGHTED IN THE CPC 3-7 DAY HAZARDOUS WEATHER OUTLOOK HAS NOW SHIFTED FURTHER TO THE EAST TO INCLUDE THE ENTIRE FORECAST AREA. WHILE PWATS ARE NOT FORECAST TO BECOME ANOMALOUSLY HIGH...REMAINING BELOW 1 STANDARD DEVIATION...THE SYSTEM IS A SLOW MOVER AND SHOWS A SOLID MOISTURE CONNECTION WITH THE WESTERN GULF OF MEXICO...VIA 850 WV TRANSPORT VECTORS. THE WPC 5-7 DAY QPF SUPPORTS CPC/S OUTLOOK...PAINTING A GENERAL 1 TO 3 INCHES ALONG WHERE THE WARM FRONT SETS UP AND THE 850MB LOW TRACKS...FROM EASTERN NEBRASKA THROUGH IOWA AND NORTHERN MISSOURI INTO ILLINOIS AND SOUTHERN WISCONSIN. THUNDERSTORM POTENTIAL...TOO EARLY TO FORECAST WITH MUCH DETAIL. HOWEVER...SOME STRONG OR SEVERE STORMS ARE POSSIBLE ON MONDAY OVER THE SOUTHWEST SECTION OF THE FORECAST AREA. WIDESPREAD CLOUDS AND THE THREAT FOR RAIN TRANSLATES INTO NO BIG WARM UPS WITH AVG HIGH TEMPS IN THE LOWER 70S. WEDNESDAY...SEASONAL TEMPS CONTINUE WITH SLIGHT CHANCES FOR SHOWERS OR AN ISOLATED STORM. UTTECH && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 615 PM CDT THU MAY 5 2016 HIGH PRESSURE WILL BRING A VERY CLEAR CALM AND VFR NIGHT TO THE REGION TONIGHT...FOLLOWED BY A VFR DAY OF CLEAR/HIGH CLOUDS FRIDAY. WINDS WILL BE LIGHT WEST TO NORTHWEST OVERNIGHT...FOLLOWED BY A TURN TO SOUTHWEST TO WEST FRIDAY AROUND 10-15 KTS THROUGH THE DAYTIME HOURS. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...HAASE SHORT TERM...HAASE LONG TERM...UTTECH AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS WICHITA KS
651 PM CDT THU MAY 5 2016 .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 240 PM CDT THU MAY 5 2016 MAIN FORECAST HIGHLIGHT IS SEVERE THUNDERSTORM POTENTIAL SATURDAY-MONDAY...BUT ESPECIALLY SUNDAY AFTERNOON-EVENING. A HIGH AMPLITUDE SHORTWAVE RIDGE PROGRESSING OVER MID-AMERICA WILL SUPPORT CONTINUED TRANQUIL WEATHER THROUGH FRIDAY NIGHT/SATURDAY. INCREASING SOUTHERLY LOW-LEVEL WINDS IN RESPONSE TO AN APPROACHING DEEP WESTERN CONUS TROUGH ALONG WITH THE INCREASING ATMOSPHERIC THICKNESS WILL HELP BOOST DAYTIME HIGH TEMPERATURES WELL INTO THE 80S FRIDAY AND SATURDAY. ISOLATED TO WIDELY SCATTERED THUNDERSTORM CHANCES SHOULD INCREASE MAINLY WEST AND NORTH OF THE FORECAST AREA SATURDAY AFTERNOON/EVENING. THE 1ST OF A COUPLE SHORTWAVES IS EXPECTED TO EJECT NORTHEAST OUT OF THE BASE OF THE WESTERN CONUS TROUGH BY AFTERNOON...DEEPENING THE SURFACE LOW AND SHARPENING A DRYLINE ACROSS THE HIGH PLAINS. MEANWHILE...A COLD FRONT WILL PROGRESS SOUTH ACROSS THE CENTRAL PLAINS IN RESPONSE TO ENERGY DROPPING SOUTHEAST OVER THE GREAT LAKES...WITH THE FRONT LIKELY STALLING OVER FAR NORTHERN KS/SOUTHERN NE BY AFTERNOON. MOISTURE RETURN WILL BE MARGINAL ACROSS THE WARM SECTOR...STUNTED BY PERSISTENT LOW-LEVEL HIGH PRESSURE ACROSS THE NORTHERN GULF OF MEXICO. HOWEVER...THINKING BOUNDARY LAYER DEWPOINTS REACHING THE 50S ARE REASONABLE...YIELDING MLCAPE VALUES AROUND 1500 J/KG...AND DEEP LAYER SHEAR AROUND 50 KTS SUPPORTING SUPERCELLS. THINKING STORM INITIATION IS MOST LIKELY NEAR THE TRIPLE POINT IN THE VICINITY OF NORTHWEST AND POSSIBLY WESTERN KS...WITH THIS ACTIVITY PROBABLY CONGEALING INTO A COMPLEX OR TWO AS IT PROGRESSES EAST/SOUTHEAST ALONG AND NORTH OF THE STALLED BOUNDARY OVER NORTHERN...CENTRAL AND EAST-CENTRAL KS. HOWEVER...SEVERE THREAT SHOULD TEND TO WANE WITH EASTERN EXTENT AS INSTABILITY DROPS OFF. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 240 PM CDT THU MAY 5 2016 MEDIUM RANGE CONSENSUS SUGGESTS THE 2ND IN A SERIES OF SHORTWAVES WILL EJECT NORTHEAST ONTO THE PLAINS SUNDAY. GFS/ECMWF SUGGEST DRYLINE SHOULD MIX A BIT FURTHER EAST WITH THIS SECOND SYSTEM (ALTHOUGH NAM IS QUITE A BIT FURTHEST WEST)...WITH BOUNDARY LAYER DEWPOINTS LIKELY INCREASING TO AT LEAST NEAR 60F BY PEAK HEATING SUNDAY. WOULDN`T BE SURPRISED IF GFS/ECMWF COME INTO BETTER AGREEMENT WITH THE SLOWER/FURTHER WEST NAM. THE ASSOCIATED INCREASED INSTABILITY ALONG WITH CONTINUED NEAR 50 KTS OF DEEP LAYER SHEAR WILL SUPPORT SEVERE STORMS...WITH INITIATION PROBABLY SOMEWHERE WEST/SOUTHWEST OF I-135/35 CORRIDOR SUNDAY AFTERNOON. DETAILS ON TIMING AND PLACEMENT OF VARIOUS FEATURES AND ORIENTATION AND MAGNITUDE OF SHEAR VALUES...ALONG WITH LOW-LEVEL MOISTURE QUALITY REMAIN IN QUESTION...BUT OVERALL PATTERN SUGGESTS DECENT POTENTIAL FOR SEVERE STORMS INCLUDING SUPERCELLS ACROSS THE CENTRAL/SOUTHERN PLAINS SUNDAY AFTERNOON-EVENING. AS THINGS CURRENTLY STAND...THINKING HIGHEST PROBABILITY WILL BE GENERALLY ALONG/WEST OF THE FLINT HILLS...WITH MAIN THREATS LARGE HAIL...DAMAGING WINDS AND AN ISOLATED TORNADO OR TWO. HOWEVER...IF LOW-LEVEL MOISTURE QUALITY INCREASES...TORNADO THREAT WILL INCREASE AS WELL. STAY TUNED. THE MAIN UPPER LOW WILL FINALLY EJECT NORTHEAST ONTO THE PLAINS MONDAY...PUSHING THE WARM SECTOR MAINLY EAST OF THE AREA...ALTHOUGH FAR EASTERN/SOUTHEAST KS MAY STILL BE UNDER THE GUN FOR SEVERE STORMS MONDAY AFTERNOON/EVENING. MODEL CONSENSUS SUGGESTS NEXT CHANCE FOR STORMS COULD ARRIVE FOR MAINLY FAR EASTERN/SOUTHEAST KS WEDNESDAY-THURSDAY...ALTHOUGH UNCERTAINTY REMAINS HIGH BETWEEN THE GFS/ECMWF SOLUTIONS AND ENSEMBLES REGARDING LARGE SCALE PATTERN EVOLUTION. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 650 PM CDT THU MAY 5 2016 ALL AREAS WL RMN VFR THRU FRI NGT & LKLY BYD WITH CLDS AT OR ABOVE 13,000FT. WINDS THAT ARE E-SE <10KTS OVERNGT WL BECOME DUE SLY FRI MRNG & INCR 14-17Z W/ GREATEST INCR IN CNTRL & SC KS WHERE 22-26KT GUSTS (25-30MPH) ARE LKLY FROM 18Z ONWARD. && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 51 84 60 85 / 0 0 0 10 HUTCHINSON 51 85 61 85 / 0 0 0 10 NEWTON 51 84 60 84 / 0 0 0 10 ELDORADO 51 83 60 83 / 0 0 0 10 WINFIELD-KWLD 51 83 60 85 / 0 0 0 0 RUSSELL 53 86 60 84 / 0 0 10 20 GREAT BEND 53 87 61 84 / 0 0 0 20 SALINA 50 84 60 85 / 0 0 0 10 MCPHERSON 50 85 61 85 / 0 0 0 10 COFFEYVILLE 49 81 58 83 / 0 0 0 0 CHANUTE 48 81 58 83 / 0 0 0 0 IOLA 48 81 58 83 / 0 0 0 0 PARSONS-KPPF 48 81 58 83 / 0 0 0 0 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ADK LONG TERM...ADK AVIATION...EPS
  [top] Area Forecast Discussion National Weather Service Dodge City KS 610 PM CDT THU MAY 5 2016 ...UPDATE TO AVIATION... .SHORT TERM...(This evening through Friday) Issued at 142 PM CDT Thu May 5 2016 Temperatures were rising faster than the forecast T curve early this morning, and a change to the Experimental HRRR appears to have captures the temperature forecast a little better in the midday. It may be a couple of degrees overdone as it is warmer than all the other guidance/blends, however with it being early May now the warming can last later in the day. The forecast high was generally bumped about 3 degrees over the area. The surface high will continue to give way to gradual troughing over eastern Colorado and the extreme western counties overnight. Much more breezy conditions to marginally windy conditions can be expected Friday. .LONG TERM...(Friday night through Thursday) Issued at 142 PM CDT Thu May 5 2016 Continued focus exists on the weekend for severe weather potential. Saturday and Sunday present somewhat different pattern recognition setups with marginal shear on Saturday, increasing by Sunday as the upper jet advances into the central High Plains. CAPES appear moderate on Saturday, and a few hail and wind producing severe storms could develop near the dryline in this marginal shear environment. The ECMWF is the model that pushes the dryline almost out of our forecast area on Sunday afternoon before convection initiation, while the GFS was far more emphatic with convection occurring farther west. Many characteristics of the mesoscale are as of yet unknown, however thunderstorms are probable this weekend. The best chance for the most widespread severe and especially tornadic threat would be more likely farther north where the models are in agreement with placement of the warm front. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 607 PM CDT Thu May 5 2016 VFR conditions will prevail at all TAF sites through early Friday afternoon. Southeast winds 5 to 15kt will persist tonight as surface high pressure in eastern Kansas and Missouri drops southward into the Ark-La-Tex Region. Winds will become more southerly mid to late Friday morning while increasing to around 20 to 30kt as a lee side trough of low pressure strengthens across eastern Colorado. && .PRELIMINARY POINT TEMPS/POPS... DDC 54 86 59 84 / 0 0 10 30 GCK 54 88 57 83 / 0 10 10 30 EHA 51 85 55 82 / 0 10 10 20 LBL 53 87 57 85 / 0 0 10 20 HYS 52 87 60 82 / 0 10 10 50 P28 54 86 60 84 / 0 0 10 20 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Russell LONG TERM...Russell AVIATION...JJohnson
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1007 PM EDT THU MAY 5 2016 .UPDATE... ISSUED AT 1007 PM EDT THU MAY 5 2016 RECENT RADAR TRENDS INDICATE THAT THE RAIN SHOWERS WILL CONTINUE TO EXPERIENCE OVERNIGHT WILL NOT SPREAD QUITE AS FAR WESTWARD...OR BE QUITE AS WIDESPREAD...AS PREVIOUSLY FORECAST. THEREFORE...THE HOURLY FORECAST GRIDS THROUGH 12Z FRIDAY HAVE BEEN UPDATED TO REFLECT THESE LATEST TRENDS. AN UPDATED ZONE FORECAST TEXT PRODUCT HAS BEEN ISSUED AS WELL. THE REST OF THE FORECAST IS IN GOOD SHAPE. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 325 PM EDT THU MAY 5 2016 WV SAT AND HRRR HAS SUGGESTED THAT THE UPPER LEVEL CLOSED LOW HAS PROGRESSED SOUTHEAST INTO WESTERN NC AND NW SC. OVERALL THE MESO MODELS AND MORE SYNOPTIC MODELS HAVE HAD A DECENT HANDLE ON THIS PROGRESSION. WE CONTINUE TO HAVE SOME SHOWERS THAT HAVE DEVELOPED ACROSS THE SOUTH AND SW PORTIONS OF THE CWA. THIS HAS BEEN DUE TO THE STEEPER LOW LEVEL LAPSE RATES...AS WE HAVE SEEN BREAKS IN THE CLOUDS. THESE LAPSE RATES ARE COMBINING WITH THE ALREADY REASONABLY STEEP MID LEVEL LAPSE RATES. OVERALL COVERAGE HAS BEEN SCATTERED WITH BETTER COVERAGE TO THE SOUTH AND EAST. RIGHT NOW MODELS DO WANT TO BRING ADDITIONAL SHOWERS IN THE FAR EAST THIS EVENING AND TONIGHT...HOWEVER BIGGEST QUESTION WOULD BE HOW MUCH COVERAGE DO WE SEE. RIGHT NOW OPTED TO LOWER POPS GIVEN SOME OF THE UNCERTAINTY. THIS UNCERTAINTY COMES WHEN LOOKING UPSTREAM RADAR COVERAGE IS QUITE LOW COMPARED TO WHAT MAY HAVE BEEN PREVIOUSLY THOUGHT AND CAMS ARE NOT HITTING IT TOO HARD EITHER. THE OTHER QUESTION WOULD BE HOW MUCH CLOUD COVER DO WE SEE TONIGHT...RIGHT NOW KEEP CLOUD COVER HIGHER IN THE EAST GIVEN THE BETTER SHOWER COVERAGE. ALSO COULD HAVE IMPLICATIONS ON TEMPS AND FOG POTENTIAL. RIGHT NOW WILL ADD SOME PATCHY DEEPER VALLEY FOG AND JUST MINOR TEMP SPLIT GIVEN THE CLOUD UNCERTAINTY. THIS UPPER LOW IS FAIRLY SLOW TO MOVE EAST...AS A OMEGA BLOCK PATTERN SETS UP ACROSS THE CENTRAL PART OF THE CONUS. THEREFORE SURFACE HIGH PRESSURE WILL BE SLOW TO BUILD NORTHEAST FROM THE GULF. THAT SAID THERE WAS A NEED FOR SHOWERS IN THE FAR EAST AND SOUTHEAST FOR FRIDAY GIVEN THE SLOW PROGRESS OF VERTICALLY STACKED LOW AND CONTINUED PVA/SHORTWAVES DIVING SOUTH. NOW FRIDAY NIGHT HEIGHTS WILL CONTINUE TO RISE AS UPPER LOW/OMEGA BLOCK BREAK DOWN AND PROGRESS EAST. THERE IS A WEAK SURFACE TROUGH OR WAVE MAY BRING SOME SLIGHT CHANCE SHOWERS TO THE FAR NORTH OVERNIGHT. OTHERWISE MOST SPOTS SHOULD DRY OUT AT THIS POINT. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 353 PM EDT THU MAY 5 2016 MODELS ARE IN REASONABLY GOOD AGREEMENT WITH AN OMEGA BLOCK PATTERN DEAMPLIFYING OVER THE WEEKEND AND EVOLVING TO MORE OR LESS A SPLIT FLOW PATTERN NEXT WEEK. THE CURRENT UPPER LEVEL SYSTEM MEANDERING OF THE APPALACHIANS AND THE SOUTHEAST IS EXPECTED TO SHIFT OFF THE EASTERN SEABOARD. AT THE SAME TIME...AN UPPER LEVEL LOW WILL MOVE FROM THE HUDSON AND JAMES BAY REGION INTO ONTARIO AND QUEBEC AND THEN INTO THE CANADIAN OVER THE WEEKEND AND INTO EARLY NEXT WEEK. A SHORTWAVE TROUGH IS EXPECTED TO MOVE THROUGH THE GREAT LAKES REGION EARLY IN THE PERIOD AND INTO THE NORTHEASTERN CONUS BY THE END OF THE WEEKEND. THIS WILL SEND A COLD FRONT INTO THE OHIO VALLEY AND APPALACHIAN REGION FROM LATE SATURDAY INTO SATURDAY NIGHT...WITH THE BOUNDARY STALLING OUT LATE IN THE WEEKEND ACROSS THE OHIO OR TENNESSEE VALLEY. THE MODEL CONSENSUS IS FOR A SMALL CHANCE OF CONVECTION ON ISENTROPIC LIFT EARLY IN THE PERIOD ON SATURDAY. A LULL IN ACTIVITY IS POSSIBLE FROM MIDDAY INTO THE AFTERNOON ON SATURDAY...WITH MORE ORGANIZED CONVECTION LIKELY SATURDAY EVENING INTO SATURDAY NIGHT. CHANCES FOR CONVECTION APPEAR TO LESSEN ON SUNDAY AS THE SHORTWAVE TROUGH DEPARTS TO THE EAST AND NORTHEAST. AN AREA OF SFC LOW PRESSURE MEANWHILE WILL BEGIN TO DEVELOP OVER THE WEEKEND IN THE LEE OF THE ROCKIES AHEAD OF THE SECOND UPPER LEVEL LOW MEANDERING FROM THE SOUTHWESTERN CONUS INTO THE ROCKIES OVER THE WEEKEND AND EVENTUALLY EJECTING INTO THE PLAINS. IN RESPONSE TO THE DEVELOPING LOW AND HEIGHT RISES OVER THE SOUTHEASTERN CONUS...THE STATIONARY FRONT SHOULD RETURN NORTH AS A WARM FRONT MONDAY INTO MONDAY NIGHT. EVEN AS THE REGION GETS INTO THE WARM SECTOR CONVECTION CANNOT BE RULED OUT AT ANY POINT ON MONDAY. THE SFC LOW PRESSURE SYSTEM SHOULD GRADUALLY TRACK FROM THE PLAINS TOWARD THE GREAT LAKES REGION AT MIDWEEK AND THEN EVENTUALLY INTO THE NORTHEASTERN CONUS. MODEL AGREEMENT FROM RUN TO RUN AND MODEL TO MODEL IN THESE DETAILS DIMINISHES GREATLY BY TUESDAY AND TUESDAY NIGHT AND ALSO CONFIDENCE IN ANY DETAILS. HOWEVER...THE OVERALL MODEL BLEND AND CONSENSUS APPEARS TO BE FOR ANOTHER PEAK IN CONVECTION CHANCES FROM LATE MONDAY NIGHT OR TUESDAY INTO THE DAY ON WEDNESDAY AS SEVERAL SHORTWAVES SHOULD MOVE THROUGH THE OHIO VALLEY AND GREAT LAKES REGION. LOCALLY HEAVY RAIN COULD BECOME A CONCERN IN LOCATIONS THAT EXPERIENCE MULTIPLE ROUNDS OF CONVECTION. TEMPERATURES SHOULD AVERAGE ABOVE NORMAL IN THE WARM SECTOR TO START THE PERIOD...ALTHOUGH TEMPERATURES SHOULD BE SUPPRESSED ON SUNDAY AND SUNDAY NIGHT WITH THE FRONT ACROSS THE AREA AND ABUNDANT CLOUD COVER ANTICIPATED. THEREAFTER...TEMPERATURES SHOULD AVERAGE A BIT ABOVE NORMAL THROUGH THE REST OF THE PERIOD...WITH HIGHS IN THE MID 70S TO AROUND 80 AND LOWS IN THE UPPER 50S TO AROUND 60. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 800 PM EDT THU MAY 5 2016 EXPECTING CONDITIONS AT THE TAF SITES TO FLUCTUATE BETWEEN VFR AND MVFR TONIGHT INTO EARLY TOMORROW MORNING...DUE TO LOW CLOUDS AND SCATTERED RAIN SHOWERS. THE RAIN SHOULD AFFECT PRIMARILY SJS...SYM...AND JKL THROUGH LATE TONIGHT. THE RAIN IS ASSOCIATED WITH AN AREA OF LOW PRESSURE ALOFT THAT IS ROTATING ACROSS THE REGION. LATER TONIGHT...6-12Z TO BE EXACT...THERE SHOULD BE ENOUGH BREAKS IN THE CLOUDS TO ALLOW FOR SOME FOG TO FORM. THE FOG WILL BE MOST WIDESPREAD AND DENSE IN THE VALLEYS AND NEAR LARGE BODIES OF WATER. SME AND LOZ MAY SEE SOME FOG AS WELL BETWEEN 9 AND 12Z FRIDAY. THE FOG SHOULD BE GONE BY 13Z. CLOUD BASES SHOULD GO TO VFR AND STAY THERE THROUGH OUT THE DAY ON FRIDAY. ISOLATED TO SCATTERED RAIN SHOWERS WILL AGAIN BE POSSIBLE IN OUR FAR EAST ON FRIDAY. SCATTERED TO BROKEN LOW TO MID LEVEL CLOUD COVER WILL ALSO BE PRESENT. WINDS SHOULD BE OUT OF THE NORTH TO NORTHWEST AT 5 TO 10KTS WITH SOME GUSTS POSSIBLE ON FRIDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...DJ LONG TERM...JP AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
800 PM EDT THU MAY 5 2016 .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 325 PM EDT THU MAY 5 2016 WV SAT AND HRRR HAS SUGGESTED THAT THE UPPER LEVEL CLOSED LOW HAS PROGRESSED SOUTHEAST INTO WESTERN NC AND NW SC. OVERALL THE MESO MODELS AND MORE SYNOPTIC MODELS HAVE HAD A DECENT HANDLE ON THIS PROGRESSION. WE CONTINUE TO HAVE SOME SHOWERS THAT HAVE DEVELOPED ACROSS THE SOUTH AND SW PORTIONS OF THE CWA. THIS HAS BEEN DUE TO THE STEEPER LOW LEVEL LAPSE RATES...AS WE HAVE SEEN BREAKS IN THE CLOUDS. THESE LAPSE RATES ARE COMBINING WITH THE ALREADY REASONABLY STEEP MID LEVEL LAPSE RATES. OVERALL COVERAGE HAS BEEN SCATTERED WITH BETTER COVERAGE TO THE SOUTH AND EAST. RIGHT NOW MODELS DO WANT TO BRING ADDITIONAL SHOWERS IN THE FAR EAST THIS EVENING AND TONIGHT...HOWEVER BIGGEST QUESTION WOULD BE HOW MUCH COVERAGE DO WE SEE. RIGHT NOW OPTED TO LOWER POPS GIVEN SOME OF THE UNCERTAINTY. THIS UNCERTAINTY COMES WHEN LOOKING UPSTREAM RADAR COVERAGE IS QUITE LOW COMPARED TO WHAT MAY HAVE BEEN PREVIOUSLY THOUGHT AND CAMS ARE NOT HITTING IT TOO HARD EITHER. THE OTHER QUESTION WOULD BE HOW MUCH CLOUD COVER DO WE SEE TONIGHT...RIGHT NOW KEEP CLOUD COVER HIGHER IN THE EAST GIVEN THE BETTER SHOWER COVERAGE. ALSO COULD HAVE IMPLICATIONS ON TEMPS AND FOG POTENTIAL. RIGHT NOW WILL ADD SOME PATCHY DEEPER VALLEY FOG AND JUST MINOR TEMP SPLIT GIVEN THE CLOUD UNCERTAINTY. THIS UPPER LOW IS FAIRLY SLOW TO MOVE EAST...AS A OMEGA BLOCK PATTERN SETS UP ACROSS THE CENTRAL PART OF THE CONUS. THEREFORE SURFACE HIGH PRESSURE WILL BE SLOW TO BUILD NORTHEAST FROM THE GULF. THAT SAID THERE WAS A NEED FOR SHOWERS IN THE FAR EAST AND SOUTHEAST FOR FRIDAY GIVEN THE SLOW PROGRESS OF VERTICALLY STACKED LOW AND CONTINUED PVA/SHORTWAVES DIVING SOUTH. NOW FRIDAY NIGHT HEIGHTS WILL CONTINUE TO RISE AS UPPER LOW/OMEGA BLOCK BREAK DOWN AND PROGRESS EAST. THERE IS A WEAK SURFACE TROUGH OR WAVE MAY BRING SOME SLIGHT CHANCE SHOWERS TO THE FAR NORTH OVERNIGHT. OTHERWISE MOST SPOTS SHOULD DRY OUT AT THIS POINT. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 353 PM EDT THU MAY 5 2016 MODELS ARE IN REASONABLY GOOD AGREEMENT WITH AN OMEGA BLOCK PATTERN DEAMPLIFYING OVER THE WEEKEND AND EVOLVING TO MORE OR LESS A SPLIT FLOW PATTERN NEXT WEEK. THE CURRENT UPPER LEVEL SYSTEM MEANDERING OF THE APPALACHIANS AND THE SOUTHEAST IS EXPECTED TO SHIFT OFF THE EASTERN SEABOARD. AT THE SAME TIME...AN UPPER LEVEL LOW WILL MOVE FROM THE HUDSON AND JAMES BAY REGION INTO ONTARIO AND QUEBEC AND THEN INTO THE CANADIAN OVER THE WEEKEND AND INTO EARLY NEXT WEEK. A SHORTWAVE TROUGH IS EXPECTED TO MOVE THROUGH THE GREAT LAKES REGION EARLY IN THE PERIOD AND INTO THE NORTHEASTERN CONUS BY THE END OF THE WEEKEND. THIS WILL SEND A COLD FRONT INTO THE OHIO VALLEY AND APPALACHIAN REGION FROM LATE SATURDAY INTO SATURDAY NIGHT...WITH THE BOUNDARY STALLING OUT LATE IN THE WEEKEND ACROSS THE OHIO OR TENNESSEE VALLEY. THE MODEL CONSENSUS IS FOR A SMALL CHANCE OF CONVECTION ON ISENTROPIC LIFT EARLY IN THE PERIOD ON SATURDAY. A LULL IN ACTIVITY IS POSSIBLE FROM MIDDAY INTO THE AFTERNOON ON SATURDAY...WITH MORE ORGANIZED CONVECTION LIKELY SATURDAY EVENING INTO SATURDAY NIGHT. CHANCES FOR CONVECTION APPEAR TO LESSEN ON SUNDAY AS THE SHORTWAVE TROUGH DEPARTS TO THE EAST AND NORTHEAST. AN AREA OF SFC LOW PRESSURE MEANWHILE WILL BEGIN TO DEVELOP OVER THE WEEKEND IN THE LEE OF THE ROCKIES AHEAD OF THE SECOND UPPER LEVEL LOW MEANDERING FROM THE SOUTHWESTERN CONUS INTO THE ROCKIES OVER THE WEEKEND AND EVENTUALLY EJECTING INTO THE PLAINS. IN RESPONSE TO THE DEVELOPING LOW AND HEIGHT RISES OVER THE SOUTHEASTERN CONUS...THE STATIONARY FRONT SHOULD RETURN NORTH AS A WARM FRONT MONDAY INTO MONDAY NIGHT. EVEN AS THE REGION GETS INTO THE WARM SECTOR CONVECTION CANNOT BE RULED OUT AT ANY POINT ON MONDAY. THE SFC LOW PRESSURE SYSTEM SHOULD GRADUALLY TRACK FROM THE PLAINS TOWARD THE GREAT LAKES REGION AT MIDWEEK AND THEN EVENTUALLY INTO THE NORTHEASTERN CONUS. MODEL AGREEMENT FROM RUN TO RUN AND MODEL TO MODEL IN THESE DETAILS DIMINISHES GREATLY BY TUESDAY AND TUESDAY NIGHT AND ALSO CONFIDENCE IN ANY DETAILS. HOWEVER...THE OVERALL MODEL BLEND AND CONSENSUS APPEARS TO BE FOR ANOTHER PEAK IN CONVECTION CHANCES FROM LATE MONDAY NIGHT OR TUESDAY INTO THE DAY ON WEDNESDAY AS SEVERAL SHORTWAVES SHOULD MOVE THROUGH THE OHIO VALLEY AND GREAT LAKES REGION. LOCALLY HEAVY RAIN COULD BECOME A CONCERN IN LOCATIONS THAT EXPERIENCE MULTIPLE ROUNDS OF CONVECTION. TEMPERATURES SHOULD AVERAGE ABOVE NORMAL IN THE WARM SECTOR TO START THE PERIOD...ALTHOUGH TEMPERATURES SHOULD BE SUPPRESSED ON SUNDAY AND SUNDAY NIGHT WITH THE FRONT ACROSS THE AREA AND ABUNDANT CLOUD COVER ANTICIPATED. THEREAFTER...TEMPERATURES SHOULD AVERAGE A BIT ABOVE NORMAL THROUGH THE REST OF THE PERIOD...WITH HIGHS IN THE MID 70S TO AROUND 80 AND LOWS IN THE UPPER 50S TO AROUND 60. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 800 PM EDT THU MAY 5 2016 EXPECTING CONDITIONS AT THE TAF SITES TO FLUCTUATE BETWEEN VFR AND MVFR TONIGHT INTO EARLY TOMORROW MORNING...DUE TO LOW CLOUDS AND SCATTERED RAIN SHOWERS. THE RAIN SHOULD AFFECT PRIMARILY SJS...SYM...AND JKL THROUGH LATE TONIGHT. THE RAIN IS ASSOCIATED WITH AN AREA OF LOW PRESSURE ALOFT THAT IS ROTATING ACROSS THE REGION. LATER TONIGHT...6-12Z TO BE EXACT...THERE SHOULD BE ENOUGH BREAKS IN THE CLOUDS TO ALLOW FOR SOME FOG TO FORM. THE FOG WILL BE MOST WIDESPREAD AND DENSE IN THE VALLEYS AND NEAR LARGE BODIES OF WATER. SME AND LOZ MAY SEE SOME FOG AS WELL BETWEEN 9 AND 12Z FRIDAY. THE FOG SHOULD BE GONE BY 13Z. CLOUD BASES SHOULD GO TO VFR AND STAY THERE THROUGH OUT THE DAY ON FRIDAY. ISOLATED TO SCATTERED RAIN SHOWERS WILL AGAIN BE POSSIBLE IN OUR FAR EAST ON FRIDAY. SCATTERED TO BROKEN LOW TO MID LEVEL CLOUD COVER WILL ALSO BE PRESENT. WINDS SHOULD BE OUT OF THE NORTH TO NORTHWEST AT 5 TO 10KTS WITH SOME GUSTS POSSIBLE ON FRIDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJ LONG TERM...JP AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
220 AM EDT WED MAY 4 2016 .UPDATE... ISSUED AT 220 AM EDT WED MAY 4 2016 CLOUDS HOLDING TOUGH THIS MORNING...BUT WITH BASES AROUND 8KFT...NOT MUCH SHOWER ACTIVITY TO SPEAK OF. STILL A FEW SHOWERS JUST NORTH OF I-64...ASSOCIATED WITH A LEFT OVER CONVERGENCE ZONE. THIS ACTIVITY WILL CONTINUE TO SLIDE EAST INTO WEST VIRGINIA THIS MORNING. MEANWHILE...VIGOROUS SHORTWAVE OVER THE NORTHERN PLAINS/GREAT LAKES THIS MORNING IS MAKING ITS MOVE SOUTH WITH A DECENT LINE OF SHOWERS AND THUNDERSTORMS ALONG THE SURFACE COLD FRONT. HAVE SEEN SOME PERSISTENT WIND GUSTS UP TO 40-45 MPH. FORTUNATELY...WITH THE FRONT BECOMING MORE NORTH/SOUTH ORIENTED BY THE TIME IT GETS HERE...NOT ANTICIPATING THE WIND THREAT TO MAKE IT INTO OUR AREA TODAY. HOWEVER...AS MENTIONED PREVIOUSLY...CONDITIONS STILL FAVORABLE FOR SOME SMALL HAIL WITH ANY THUNDERSTORMS THAT FORM WITH SUCH LOW FREEZING LEVELS. IN FACT...ALREADY NUMEROUS REPORTS OF SMALL HAIL OVERNIGHT ACROSS SOUTHERN WISCONSIN. UPDATE ISSUED AT 1039 PM EDT TUE MAY 3 2016 PARTIAL CLEARING HAS ALLOWED FOR SOME TEMPERATURE DROP OFF IN PLACES...HOWEVER MOSTLY CLOUDY SKIES LOOK TO MOVE BACK IN OVERNIGHT...SO LOWS IN THE UPPER 40S STILL LOOK ON TARGET. ISOLATED SHOWERS CONTINUE TO POP UP WITH THE APPROACH OF A SHORT WAVE TROUGH...AND THE LATEST HRRR SHOWS AT LEAST WEAK RETURNS AT TIMES THROUGH EARLY WEDNESDAY MORNING. HAVE UPDATED TEMPERATURES AND DEW POINTS OVER THE NEXT SEVERAL HOURS TO ACCOUNT FOR THE LATEST TRENDS...OTHERWISE THE FORECAST REMAINS ON TRACK. UPDATES HAVE BEEN SENT. UPDATE ISSUED AT 823 PM EDT TUE MAY 3 2016 THE FORECAST IS ON TRACK. A FEW SHOWERS ARE DOTTING PORTION OF THE AREA...MAINLY NORTH OF I-64. THESE WILL CONTINUE TO THREATEN THROUGH THE NIGHT AS A SHORT WAVE TROUGH MOVES THROUGH THE OHIO VALLEY. FRESHENED UP THE HOURLY TEMPERATURES AND DEW POINTS TO ALIGN BETTER WITH THE CURRENT TRENDS IN OBSERVATIONS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 402 PM EDT TUE MAY 3 2016 CURRENT CONDITIONS ACROSS THE AREA THIS AFTERNOON FEATURE SOME LOW LEVEL MOISTURE HANGING AROUND THE APPALACHIAN REGION AS THE BOUNDARY THAT HAD SPARKED SOME SIGNIFICANT CONVECTION OVER THE AREA YESTERDAY HAS MOVED OFF TO THE EAST. SURFACE HIGH PRESSURE WILL SLOWLY NUDGE IN FROM THE WEST. WITH STOUT LOW PRESSURE EXITING THE AREA AND THE NEXT WAVE DIVING SOUTHEAST FROM THE GREAT LAKES REGION...LINGERING CLOUD COVER WILL BUILD BACK INTO THE AREA LATE TONIGHT. WITH A FEW BREAKS TODAY IN THE CLOUD COVER...SOME ISOLATED SHOWERS DID DEVELOP AND WILL SLOWLY DIMINISH HEADING INTO THE OVERNIGHT HOURS IN THE SOUTH. AS A WEAK WAVE PASSES THE AREA TONIGHT A FEW SHOWERS WILL POP UP AGAIN THE NORTH. THE CONTINUED CLOUD COVER WILL KEEP THE DEVELOPMENT OF FOG UNLIKELY. HEADING INTO THE DAY TOMORROW...A STRONG SHORT WAVE WILL SWING THROUGH THE OH VALLEY BY THE AFTERNOON AND INTO THE EVENING. WITH A DECENT GRADIENT IN THE FRONT MOVING THROUGH...WINDS WILL BE QUITE GUSTY WITH THE FRONT...HOWEVER INSTABILITY WILL BE LACKING. WILL EXPECT SHOWERS AND A FEW THUNDERSTORMS THROUGH THE AFTERNOON. WITH JUST ENOUGH INSTABILITY AND FORCING FROM THE FRONT...SOME LOWER FREEZING HEIGHTS WILL LEAD TO A FEW INSTANCES OF SMALL HAIL. A COLD CORE LOW STALLING OVERHEAD INTO THE OVERNIGHT HOURS WILL LEAD TO COOLER TEMPS OVERNIGHT WEDNESDAY NIGHT AND LINGERING CLOUD COVER. IN FACT...TEMPS WILL DROP INTO THE LOWER 40S AND POSSIBLY SOME UPPER 30S. OVERALL...WITH THE EXCEPTION OF WEDNESDAY AFTERNOON...THE PERIOD LOOKS TO BE CLOUDY...COOL...AND A FEW SHOWERS. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 303 PM EDT TUE MAY 3 2016 A DEEP CLOSED LOW WILL BE PASSING ACROSS KY TO START OFF THE EXTENDED PERIOD...PULLING MUCH COOLER CANADIAN AIR DOWN INTO THE REGION. THE LOW WILL SLOWLY SHIFT SOUTHEAST OF THE AREA THROUGH THE DAY THURSDAY AND THURSDAY NIGHT...KEEPING STRONG N TO S FLOW ACROSS MUCH OF THE REGION INTO THE DAY SATURDAY...WHILE THE LOW REMAINS PARKED ALONG THE EASTERN SEABOARD. AT THIS POINT...ANOTHER STRONG UPPER LEVEL LOW OVER HUDSON BAY IN CANADA WILL BEGIN DROPPING SOUTHWARD. THE LOW TO OUR EAST WILL BEGIN TO DISSOLVE AND MERGE INTO THE INCOMING LOW AS IT CONTINUES TO PUSH SOUTHWARD SATURDAY INTO SUNDAY. WHILE THE UPPER LOW WILL STAY TO OUR NE...EXPECT THE RETURN OF NW FLOW TO THE REGION DURING THIS TIME FRAME. THE LOW WILL THEN START SHIFTING EASTWARD...WITH UPPER LEVEL RIDGING TAKING HOLD THROUGH THE DAY MONDAY. LINGERING PRECIP IS EXPECTED THROUGH THE DAY THURSDAY AND EVEN INTO THURSDAY NIGHT...MAINLY IN THE SE ALONG THE HIGHER TERRAIN DUE TO LINGERING MOISTURE AND NW TO SE UPSLOPE FLOW THROUGH THE DAY. SO LONG AS THE UPPER LEVEL LOW AND SURFACE LOW STAY POSITIONED OVER THE EASTERN COAST...THIS NW FLOW WILL BE IN PLACE. THE STRONG N TO S FLOW ALOFT WILL ALSO PULL IN DEEP CAA...WITH HIGHS THURSDAY ONLY REACHING THE LOW TO MID 50S. AS CONDITIONS BEGIN CLEARING THURSDAY NIGHT...EXPECT TEMPS TO DROP OFF TO THE LOW TO MID 40S...WITH COLDEST TEMPS LIKELY IN THE VALLEYS. FRIDAY WILL SHOW SOME IMPROVEMENT...BUT HIGHS GENERALLY IN THE UPPER 60S IS STILL BELOW SEASONABLE NORMS FOR THE BEGINNING OF MAY. THE FLOW ALOFT WILL WEAKEN SATURDAY AS UPPER LEVEL RIDGING NUDGES INTO THE CENTRAL PLAINS. SURFACE HIGH PRESSURE WILL KEEP CONDITIONS MOSTLY CLEAR...AND TEMPERATURES WILL BE ALLOWED TO RISE INTO THE MID AND UPPER 70S AS WINDS BECOME MORE WRLY NEAR THE SURFACE...TAPPING INTO WARMER GULF FLOW COMING OUT OF TEXAS. THE NEXT UPPER LEVEL LOW DROPPING DOWN FROM CANADA WILL PUSH A COLD FRONT SOUTHWARD... ENTERING INTO THE OHIO VALLEY SATURDAY NIGHT...BECOMING NEARLY STATIONARY ACROSS THE STATE DURING THE DAY SUNDAY. WHILE MOST OF THE MOISTURE WILL BE CONTAINED CLOSER TO THE UPPER LEVEL AND SURFACE LOW TO OUR NE...STILL EXPECT SOME LOW END CHANCE POPS TO MAKE IT INTO OUR CWA...MAINLY IN THE NORTHERN HALF...BEGINNING SATURDAY NIGHT AND CONTINUING ALL THE WAY INTO MONDAY...DESPITE UPPER LEVEL RIDGING TAKING HOLD. GENERALLY WRLY FLOW...EVEN ALOFT...AT THIS POINT...WILL CONTINUE TO PULL IN WARMER TEMPS...TAPPING INTO THE GULF MOISTURE ACROSS TX. THIS WILL KEEP TEMPS IN THE 70 DEGREE RANGE THROUGH THE WEEKEND AND STARTING OUT THE NEXT WEEK AS WELL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 220 AM EDT WED MAY 4 2016 VFR CONDITIONS LOOK TO HANG ON FOR MOST LOCATIONS THROUGH THE NEXT 9 TO 12 HOURS. AN UPPER LEVEL DISTURBANCE WILL BRING SHOWERS AND A FEW THUNDERSTORMS TO THE AREA AFTER 17Z TODAY. CEILINGS AND VISIBILITIES WILL GRADUALLY LOWER TO MVFR THROUGH THE REST OF THE PERIOD. WINDS WILL BE OUT OF THE WEST AND NORTHWEST...GENERALLY IN BETWEEN 5 AND 10 KTS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...SHALLENBERGER LONG TERM...JMW AVIATION...KAS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1004 PM EDT THU MAY 5 2016 .SYNOPSIS... LOW PRESSURE WILL MOVE UP FROM THE SOUTH TONIGHT AND MOVE ACROSS NOVA SCOTIA FRIDAY MORNING. HIGH PRESSURE WILL BRIEFLY BUILD OVER THE AREA FRIDAY AFTERNOON AS ANOTHER WEAK LOW REACHES THE MID ATLANTIC COAST. && .NEAR TERM /THROUGH FRIDAY/... 925 PM UPDATE: THE TREND OF HRLY HRRR SIM RADAR MODEL SOLUTIONS OVR THE LAST FEW HRS IS TO SHOW LESS NWRD PROGRESS OF STEADY RN INTO OUR FA FROM JUST THE LAST UPDATE. THIS SEEMS TO MATCH UP WITH TRENDS SEEN IN LATEST REAL TIME RADAR REF IMAGERY WHICH SHOWS RN STRUGGLING TO MAKE IT INTO E CNTRL PTNS OF THE FA LATE THIS EVE AND SFC OBS AND SAT IMAGERY WHICH SHOWS INTERMITTENT BREAKS IN CLD CVR WITH A WEDGE OF DRY SUB CLD AIR OVR THE NW HLF OF THE FA XTNDG EWRD FROM QB. BASED ON THESE TRENDS...WE LOWERED FORECAST QPF AND POPS SOMEWHAT FOR THE REMAINDER OF THE OVRNGT OVR THE N AND CNTRL THIRDS OF THE FA. WITH BREAKS IN THE OVC OVR THE FAR NW...TEMPS HAVE FALLEN A LITTLE FASTER ACROSS BROAD VLY LCTNS OVR THIS PTN OF THE FA...SO WE LOWERED FCST LOWS OVR NW PTNS OF AROOSTOOK COUNTY WITH THE UPDATE OF FCST HRLY TEMPS OVRNGT FOR ALL OF THE REGION. ORGNL DISC: LOW PRESSURE CURRENTLY SPINNING WELL OFF THE MID ATLANTIC COAST WILL LIFT NORTHWARD TOWARD NOVA SCOTIA THIS AFTERNOON AND EVENING, THEN RAPIDLY MOVE TO THE EAST LATE TONIGHT. WE`RE ALREADY SEEING MOISTURE LIFTING INTO SOUTHERN PORTIONS OF OUR FORECAST AREA, AS EVIDENCED BY PERIODS OF DRIZZLE AND FOG. THE RAIN WON`T BE FAR BEHIND AND SHOULD BEGIN TO MOVE ONSHORE BY EARLY THIS EVENING. AS WITH LAST NIGHT`S RAIN, DOWNEAST AREAS WILL SEE THE BULK OF THE PRECIPITATION, WITH AREAS NORTH OF A HOULTON TO MILLINOCKET LINE SEEING JUST SOME SHOWERS. LITTLE TO NO RAINFALL IS EXPECTED IN THE SAINT JOHN VALLEY. COASTAL AREAS COULD SEE ANOTHER HALF INCH OR SO, WITH FAR WASHINGTON COUNTY RECEIVING A LITTLE MORE. THE RAIN WILL BE A QUICK SHOT GIVEN THE LOW`S RAPID FORWARD PROGRESSION AND WILL EXIT INTO NEW BRUNSWICK BY DAYBREAK FRIDAY. IT`LL BE A BIT BREEZY OVERNIGHT AS WELL, ESPECIALLY DOWNEAST, AS THE PRESSURE GRADIENT TIGHTENS IN RESPONSE TO THE PASSING LOW. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 30S IN THE NORTH WOODS TO THE LOWER 40S DOWNEAST. PLEASANT WEATHER MOVES IN FOR FRIDAY AS THE LOW CONTINUES TO PULL AWAY, ALLOWING HIGH PRESSURE TO BUILD IN ITS WAKE. SKIES WILL GRADUALLY CLEAR FROM NORTHWEST TO SOUTHEAST THROUGH THE DAY; EXPECT EVERYONE WILL SEE AT LEAST PARTIAL SUN BY MID AFTERNOON. HIGHS WILL REACH INTO TO THE LOWER 60S IN MOST SPOTS, THE EXCEPTION WILL BE DOWNEAST WHERE THE CLOUDS WILL HANG IN LONGEST; HIGHS WILL BE IN THE MID TO UPPER 50S THERE. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... THE WEEKEND WILL FEATURE THE CUT-OFF LOW FINALLY GETTING ABSORBED BACK INTO THE MAIN WEATHER PATTERN AND A DIGGING TROF MOVING ACROSS QUEBEC. FRIDAY NIGHT WILL START OFF CLEAR, BUT HIGH CLOUDS WILL SPREAD BACK NORTH AFTER MIDNIGHT AND THICKEN THRU THE DAY ON SAT. AS THE CUT-OFF GETS ABSORBED BACK INTO THE UPR TROF AND ITS MOISTURE STREAMS BACK NORTH AHEAD OF THE ADVANCING COLD FRONT, MAY HAVE SOME ISO TO SCT SHWRS LATE SAT AM THRU SAT NIGHT. THE BEST CHANCE FOR RAIN WILL BE AS THE FRONT CROSSES THE CWA DURING THE AFTN AND EVE ON SUN. THERE ARE MINOR DIFFERENCES IN THE EXACT TIMING OF THE FRONT, BUT FELT CONFIDENT TO INTRODUCE LKLY TO LOW- END DEF POPS. CURRENTLY GOING FOR QPF OF A QUARTER TO HALF AN INCH. TEMPS WILL BE ABV NRML SAT, BUT INCR CLOUDS AND AFTN PRECIP WILL LIKELY TAMP DOWN TEMPS A BIT ON SUN. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... SOME PRECIP LKLY TO BE ONGOING ALONG THE N AND E BORDERS AT 00Z MON START OF THE LONG TERM, BUT QUICKLY DIMINISHES. HWVR, SIGNIFICANT DISAGREEMENTS QUICKLY DEVELOP REGARDING THE SPEED OF THE UPR TROF DEPARTING THE REGION, AND THE POTENTIAL FOR CLOUDS AND A FEW SHWRS TO LINGER UP NORTH. MODELS SHOW A WEAK SFC SYSTEM MOVING ACROSS SRN NEW ENG TUE NIGHT THRU WED NIGHT, BUT ALSO DISAGREE QUITE A BIT ON THE NORTHWARD EXTENT OF PRECIP, SO KEPT POPS AT CHC FOR NOW. 12Z ECMWF SEEMS TO BE CLOSER TO THE GFS AND CMC SOLUTIONS, SO FUTURE FORECAST CYCLES MAY BE ABLE TO HAVE A BIT MORE CERTAINTY IF THAT TREND HOLDS. TEMPS ON MON LKLY TO BE A BIT BLW NRML BEHIND THE FRONT, BUT QUICKLY REBOUND TO NEAR OR A BIT ABV NRML THE REST OF THE LONG TERM. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... NEAR TERM: ALL SITES CURRENTLY UNDER PREVAILING MVFR CEILINGS AND THIS SHOULD BE THE GENERAL TREND THROUGH 00Z FRIDAY, THOUGH THE NORTHERN TERMINALS MAY SEE A PERIOD OF VFR. THEN CONDITIONS WILL DETERIORATE AS LOW PRESSURE SWINGS BY TO THE SOUTHEAST AND BRINGS A PERIOD OF RAIN. KBGR AND KBHB WILL SEE THE STEADIEST RAIN AS WELL AS THE LONGEST PERIOD OF IFR CONDITIONS (00Z-11Z). THE NORTHERN TERMINALS ARE MORE LIKELY TO SEE JUST SOME SHOWERS AT MOST, BUT CEILINGS WILL LOWER TO BELOW 1000 FT LATE TONIGHT. CONDITIONS WILL IMPROVE AFTER 12Z AS SKIES CLEAR FROM NORTHWEST TO SOUTHEAST. ALL SITES VFR BY 18Z. SHORT TERM: EXPECT VFR AT ALL SITES FRI NIGHT, EXCEPT PATCHY FOG CAN`T BE RULED OUT, SPCLY KHUL SOUTH TO THE COAST AS WINDS MAY BE A BIT LIGHTER THERE. HIGH CIGS SPREAD OVER THE CWA FROM SOUTH TO NORTH SAT AND SAT NIGHT. EXPECT CONTINUING VFR AT FIRST, THOUGH ANY SHWRS LATER SAT INTO SUN AM COULD BRING SOME MVFR CONDITIONS. AS THE FRONT PUSHES THRU THE STATE FROM W TO E BETWEEN 18Z SUN AND 06Z MON, EXPECT MVFR TO IFR CONDITIONS FOR ALL SITES. CIGS WILL INCREASE ONCE THE FRONT CLEARS THE AREA, BUT AS THE UPR TROF REMAINS OVER HEAD, COULD SEE SOME MVFR CIGS AT TIMES MON, SPCLY IF ANY SHWRS LINGER. && .MARINE... NEAR TERM: THE SMALL CRAFT ADVISORY REMAINS IN PLACE AS WINDS WILL CONTINUE TO GUST TO 30 KT THIS EVENING AND OVERNIGHT. THIS WILL LIKELY NEED TO BE CONVERTED OVER TO AN SCA FOR HAZARDOUS SEAS FRIDAY MORNING TO EXTEND THROUGH THE DAY. SEAS WILL BE 5-9 FEET. SHORT TERM: WINDS EXPECTED TO REMAIN BELOW SCA CRITERIA THRU THE SHORT TERM, BUT SEAS WILL REMAIN ABOVE CRITERIA LEVELS FRI NIGHT THRU SAT. SEAS LOOK TO SETTLE SOME SAT NIGHT INTO SUN, AND MAY ALLOW THE ANTICIPATED SCA FOR HAZARDOUS SEAS TO BE DROPPED. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR ANZ050>052. && $$ NEAR TERM...VJN SHORT TERM...KREDENSOR LONG TERM...KREDENSOR AVIATION...VJN/KREDENSOR MARINE...VJN/KREDENSOR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
718 PM EDT THU MAY 5 2016 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 354 PM EDT THU MAY 5 2016 12Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW A NNW FLOW ALOFT DOMINATING THE WRN GREAT LKS BTWN DEEP UPR TROF OVER THE E AND AN UPR RDG IN CENTRAL NAMERICA. A SFC HI PRES RDG STRETCHING FM THE UPR MIDWEST INTO WRN QUEBEC AS WELL AS DRY AIRMASS SHOWN ON THE 12Z GRB RAOB IS BRINGING A MOSUNNY DAY TO UPR MI...BUT MORE MAINLY MID/HI CLDS RELATED TO WAA IN THE SW FLOW ON THE BACK SIDE OF THE RDG ARE PRESENT FM WRN LK SUP INTO CENTRAL ONTARIO. THERE WERE SOME SHOWERS UNDER THESE CLDS OVER MN WHERE MID LVL LAPSE RATES HAVE BEEN STEEPER...BUT ABSENCE OF FORCING OTHER THAN WAA AND RELATIVELY DRY NATURE OF THE AIRMASS ARE LIMITING THE COVERAGE OF THIS PCPN...WITH A DIMINISHING TREND IN RECENT HRS. TNGT...AS SFC HI PRES RDG CONTINUES TO SLIDE SEWD...SW FLOW/WAA ARE PROGGED TO DOMINATE THE CWA. EXPECT SOME MID/HI CLDS RELATED TO THIS WAA TO PASS OVER THE CWA MAINLY THRU 06Z BEFORE SUBSIDENCE RELATED TO SHARPENING H7 RDG AXIS DRIES UP THESE CLDS. CONSIDERED ADDING SOME ISOLD SHOWERS LATE THIS AFTN/THIS EVNG OVER THE FAR W WHERE NAM SHOWS POCKET OF H7-5 LAPSE RATES ARND 8C/KM AND SOME OF THE HIER RES MODELS GENERATE SPOTTY QPF...BUT LATEST RADAR TRENDS SUG THE AIRMASS IS SO DRY IN A RELATIVE SENSE THAT THE DRY FCST GUIDANCE IS ON THE RIGHT TRACK. COMBINATION OF THE WAA CLDS AND LLVL WARMING RELATED TO STEADY SW FLOW WL HOLD MIN TEMPS UP MUCH HIER THAN THIS MRNG. IN FACT...READINGS MAY NOT FALL BLO 50 OVER THE FAR W FM IRONWOOD TO ONTONAGON WHERE THE SW FLOW WL DOWNSLOPE. FRI...UPR MI WL BE IN THE WARM SECTOR BTWN DEPARTING SFC HI PRES RDG TO THE SE AND SFC LO PRES TRACKING ACROSS NW ONTARIO AHEAD OF SHRTWV MOVING OVER WRN RDG AND INTO FAR NW ONTARIO LATE IN THE DAY. WITH H85 TEMPS FCST AS HI AS 18C AND A GOOD DEAL OF SUNSHINE WITHIN LINGERING DRY AIRMASS...TEMPS AWAY FM THE MODERATING INFLUENCE OF MAINLY LK MI OVER THE W HALF WL RISE WELL INTO THE 80S AND PERHAPS ARPCH 90 AT A FEW LOCATIONS. WITH DAYTIME MIXING CAUSING SFC DEWPTS TO DROP AT LEAST CLOSE TO 40 IN THE AFTN...EXPECT MIN RH TO DIP NEAR 20 PCT AT A FEW PLACES. ALTHOUGH STRONG WINDS ARE NOT EXPECTED WITH GUSTS UP TO ARND 20 MPH...FIRE WX CONCERNS WL BE ELEVATED. WINDS WL BE A BIT STRONGER OVER THE E...BUT MODERATION OFF LK MI WL LIMIT FIRE WX CONCERNS THERE. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 319 PM EDT THU MAY 5 2016 LONG TERM STARTS AT 00Z SAT WITH THE UPPER RIDGE AND WARM AIRMASS OVER THE REGION. 850MB TEMPS WILL BE AROUND 17C AT 00Z...BUT WILL DROP TO 1-2C BY 18Z SAT BEHIND A SHORTWAVE TROUGH AND COLD FRONT. MODELS CONTINUE TO PAINT UP TO 0.20 INCHES OF QPF OVER MUCH OF THE AREA FRI NIGHT...BETWEEN 00Z AND 12Z SAT...BUT SOME AREAS MAY NOT EVEN SEE 0.10 INCHES. EXPECT THUNDERSTORMS AS ELEVATED INSTABILITY (CAPE UP TO 750 J/KG)...BUT NO SEVERE THUNDERSTORMS DUE TO WEAK SHEAR (0-6KM BULK SHEAR AROUND 20KTS). DRY AIR MOVES BACK IN ON SAT WITH SUNNY SKIES AND MIN RH VALUES IN THE MID 20S OVER THE INTERIOR W AROUND AROUND 40 PERCENT INTERIOR E. WINDS WILL BE LIGHT OVER THE W AND WILL GUST UP TO 25 MPH OVER THE E. IT WILL BE COOLER WITH HIGHS IN THE 50S NEAR LAKE SUPERIOR AND E AND AROUND 60 INTERIOR W. CERTAINLY NOT A CRITICAL FIRE WEATHER DAY BUT THE DRY AIR WILL PROBABLY NEGATE ANY MOISTURE WE GET FRI NIGHT. CAN NOT COMPLETELY RULE OUT A FEW LIGHT SHOWERS OVER NORTHERN LAKE SUPERIOR AND POSSIBLY THE KEWEENAW AND ERN UPPER MI SAT EVENING INTO SAT NIGHT AS ANOTHER SHORTWAVE PASSES N OF THE AREA...BUT THINK POTENTIAL IS LOW ENOUGH TO LEAVE OUT OF THE FORECAST FOR LAND AREAS. SUN WILL SEE SIMILAR TEMPS/RH/CLOUDS TO SAT...BUT WITH LOWER WINDS. MON AND TUE HAD APPEARED WET FROM EARLIER MODEL RUNS...BUT THOSE MODELS HAVE TRENDED DRIER. NOW ONLY THE 00Z/05 ECMWF SHOWS PRECIP OVER THE CWA...EXCEPT THE GLOBAL GEM WHICH HAS PRECIP BRUSHING SRN MENOMINEE COUNTY. WILL ACCORDINGLY START A DECREASING TREND FOR THE POP FORECAST FOR MON THROUGH TUE. NO PRECIP EXPECTED TUE NIGHT THROUGH THU. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 717 PM EDT THU MAY 5 2016 EXPECT VFR CONDITIONS AND RELATIVELY LIGHT WINDS MOSTLY UNDER 10KT TO PREVAIL THRU THIS FCST PERIOD AT KIWD/KCMX/KSAW AS A DRY AIR MASS WILL LINGER DESPITE HIGH PRES EXITING AND A COLD FRONT APPROACHING FRI AFTN. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 354 PM EDT THU MAY 5 2016 SSW WINDS UP TO 20 KTS AHEAD OF AN APPROACHING COLD FRONT WILL SHIFT TO THE N AT 20-25 KTS FRI NIGHT INTO SAT FOLLOWING THE PASSAGE OF THIS BOUNDARY. AS HI PRES BUILDS OVER THE AREA BY LATE IN THE WEEKEND...THESE WINDS WILL DIMINISH UNDER 15-20 KTS INTO EARLY NEXT WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...TITUS AVIATION...ROLFSON MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
402 PM EDT WED MAY 4 2016 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 401 PM EDT WED MAY 4 2016 WV IMAGERY AND RAP ANALYSIS INDICATED AN AMPLIFIED PATTERN WITH A RIDGE FROM HE ROCKIES INTO SASK AND A TROUGH FROM JAMES BAY THROUGH ERN UPPER MI TO INDIANA. AT THE SFC...GUSTY NORTH WINDS PREVAILED THROUGH LAKE SUPERIOR AND UPPER MI BETWEEN 1001 MB LOW PRES OVER SRN LOWER MI AND A RIDGE FROM NW ONTARIO INTO THE ERN DAKOTAS. VIS SATELLITE LOOP SHOWED THINNING CLOUDS OVER UPPER MI AS THE 900-700 MB MOISTURE THINS OUT WITH DAYTIME MIXING AND THE RIDGE BUILDING INTO THE AREA. TONIGHT...ALTHOUGH THE CLEARING TREND HAS BEEN A BIT SLOWER THAN FCST...EXPECT THAT BTWN 21Z-24Z MOST OF THE REMAINING CLOUDS WILL DISSIPATE. FAVORABLE RADIATIONAL COOLING CONDITIONS OVER THE WEST WHERE WINDS WILL BE LIGHTEST WILL ALLOW TEMPS TO DROP TO THE LOWER END OF GUIDANCE WITH MIN READINGS IN THE MID 20S OVER THE INTERIOR. OTHERWISE...EXPECT LOWS IN THE LOW TO MID 30S. THURSDAY...MID LEVEL AND SFC RIDGING INTO THE WRN LAKES WILL RESULT IN MOSTLY SUNNY SKIES AND WARMER WEATHER. EXPECT TEMPS TO CLIMB INTO MID TO UPPER 50S INLAND. THE WEAK GRADIENT WILL ALLOW PROMINENT LAKE BREEZE DEVELOPMENT KEEPING MAX READINGS IN THE 50S NEAR THE GREAT LAKES. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 314 PM EDT WED MAY 4 2016 UPPER TROUGH MOVES FROM THE GREAT LAKES TO THE SOUTHEAST CONUS BY FRI...ALLOWING UPPER RIDGE AND SFC WARM FRONT TO BRING WARM SUMMERLIKE TEMPS BRIEFLY OVER THE GREAT LAKES FOR FRI AFTN. INITIAL WARM AIR ADVECTION ON EDGE OF STEEPER H7-H5 LAPSE RATES UP TO 8C/KM COULD TRIGGER ELEVATED CONVECTION OVER MAINLY LK SUPERIOR THU NIGHT INTO FRI MORNING WHERE STRONGEST H85 WARM AIR ADVECTION LINKS UP WITH SUFFICIENT H85-H7 MOISTURE. FARTHER SOUTH ACROSS UPR MICHIGAN...EXPECT SCT MID CLOUDS TO START THE DAY FRI...THEN MOSTLY SUNNY SKIES BY AFTN WITH H85 TEMPS TO +16 SUPPORTS GOING FORECAST OF 70S EAST DOWNSTREAM OF LK MICHIGAN TO MID-UPR 80S WEST IN THE AFTN. DWPNTS SHOULD BE IN THE LOW TO MID 40S...SO RH VALUES DROP TO 20-25 PCT IN THE AFTN. SW-S WINDS LOOKS SLIGHTLY STRONGER THAN EARLIER MODEL FORECASTS SHOWED BUT STILL GUSTS PEAKING AT 20 MPH WILL KEEP AREA BLO CRITICAL FIRE WEATHER THRESHOLDS. WILL BE SOMETHING TO KEEP EYE ON IN TERMS OF IF STRONGER TREND IN WINDS CONTINUES. NAM/GFS TRY TO SHOW POCKET OF DWPNTS FM LOW-MID 50S AND THUS GENERATE SBCAPE OVER 1000J/KG OVER CNTRL CWA FRI AFTN AND SHOW SOME CONVECTION. COULD MAYBE SEE DWPNTS UP TO 50 LOCALLY MAINLY NEAR WI BORDER SOUTH CNTRL. OVERALL PATTERN WITH LOWERING H85-H7 RH FAVORS DEEPER MIXING AND LOWER DWPNTS...SO WILL KEEP FRI AFTN WARM BUT WITH NO CHANCE OF SHRA/TSRA. WARMTH WILL BE BRIEF AS SHORTWAVE TROUGH CROSSING NORTHERN ONTARIO PUSHES SFC-H85 COLD FRONT ACROSS UPR MICHIGAN LATE EVENING NORTHWEST TO OVERNIGHT SCNTRL. EVEN THOUGH STRONGER PVA STAYS NORTH CLOSER TO TRACK OF MAIN SHORTWAVE ACROSS ONTARIO...DIFFLUENT H5-H3 FLOW AND CONVERGENCE ALONG FRONT FAVORS BROKEN BAND OF SHOWERS AND POSSIBLE TSRA WITH CONDITIONALLY UNSTABLE H7-H5 LAPSE RATES NEAR 7C/KM. AS FOR STRENGTH OF TSRA...UNLESS FRONT ARRIVES 00Z-03Z INSTEAD OF MORE 03Z-06Z...LIKELY LOOKING AT ELEVATED STORMS. ELEVATED MUCAPE FORECASTS VARY WITH NAM SHOWING UP TO 2000J/KG AT 00Z SAT MAINLY OVER NORTHERN WI WHILE GFS/ECMWF ARE MAINLY 500J/KG OR LESS. ECMWF KEEPS MOST INSTABILITY FARTHER WEST/SOUTHWEST OF CWA FRI NIGHT. MEAN FLOW IS WNW SO IF ECMWF IS CORRECT...MOST OF TSRA WOULD REMAIN SOUTHWEST OF CWA. IF MODELS WITH MORE BULLISH INSTABILITY FARTHER EAST ARE CORRECT...THERE IS ENOUGH EFFECTIVE BULK SHEAR TO RESULT IN STRONGER STORMS. SPC HAS MOST OF CWA WITHIN GENERAL TSRA RISK FRI AND FRI NIGHT WHICH SEEMS REASONABLE WITH MAIN HINDRANCE THE DEGREE OF INSTABILITY. ATTM LOOKS LIKE TOTAL RAINFALL FRI NIGHT INTO EARLY SAT WILL BE LESS THAN 0.25 INCHES AT MOST LOCATIONS...SIMILAR TO FROPA THAT JUST OCCURRED TUE AFTN INTO THIS MORNING. TURNING BREEZY AND MUCH COOLER ON SAT BEHIND THE FRONT. WILL NOT BE A COOL AS TODAY BUT THE COOLING WILL BE SIGNIFICANT COMPARED TO THE SUMMERTIME WARMTH ON FRI...ESPECIALLY NEAR LK SUPERIOR. SHOULD DRY OUT WITH RH VALUES DOWN TO 25-30 PCT SAT AFTN. IF SHOWERS AND TSRA ARE MORE SPOTTY ON FRI NIGHT RESULTING IN MINIMAL RAIN...THE STRONGER WINDS AND LOW RH WOULD RESULT IN SOME FIRE WEATHER ISSUES ON SAT AFTN OVER INTERIOR WEST AS TEMPS STILL REACH INTO THE 60S. RE-INFORCING SHORTWAVE DIGGING INTO MEAN TROUGH OVER GREAT LAKES AND POCKET OF STEEPER LAPSE RATES OVER 7C/KM MAY BRING ANOTHER CHANCE OF ISOLD-SCATTERED ELEVATED CONVECTION SAT NIGHT MAINLY OVER EAST HALF. A BIT QUICKER TREND IN MODELS SUGGESTS SHRA/TSRA COULD MOVE OVER KEWEENAW AS EARLY AS MID-LATE SAT AFTN. OTHERWISE...REST OF LONG TERM SUN INTO MIDDLE OF NEXT WEEK LOOKS GENERALLY DRY. WILL HAVE TO KEEP SLIGHT CHANCES IN THERE IN CASE UPPER TROUGH MOVING OUT OF PLAINS COMES FAR ENOUGH NORTH TO BRING SOME SHOWERS TUE AND/OR WED. LATEST ECMWF WOULD POINT TO AT LEAST A SMALL CHANCE...ESPECIALLY SOUTH. TEMPS SHOULD BE NEAR NORMAL WITH 60S INLAND AND 50S ALONG THE GREAT LAKES AS HIGH PRESSURE RIDGE IN VCNTY RESULTS IN LAKE BREEZES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 200 PM EDT WED MAY 4 2016 LOW-LEVEL MOISTURE BEHIND A MID-LEVEL LOW PASSING TO THE EAST WILL KEEP MVFR CIGS GOING AT KCMX AND KSAW THROUGH MUCH OF THE AFTERNOON. CLOUDS WILL SCATTER OUT FROM WEST TO EAST DURING THE AFTERNOON...WITH ALL SITES SKC AFTER 00Z. EXPECT GUSTY NORTH WINDS TO 25 KNOTS TODAY AT BOTH KCMX AND KSAW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 401 PM EDT WED MAY 4 2016 GUSTY NORTH WINDS TO 25 KNOTS OVER ERN LAKE SUPERIOR WILL QUICKLY DIMINISH TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE REGION. EXPECT WINDS TO BE GENERALLY SOUTHERLY UNDER 20 KNOTS THURSDAY THROUGH FRIDAY. A COLD FRONT WILL THEN SWEEP ACROSS LAKE SUPERIOR FRIDAY EVENING...BRINGING A QUICK ROUND OF NW WINDS TO 30 KNOTS LATE FRIDAY NIGHT AND SATURDAY MORNING. WINDS WILL THEN REMAIN WESTERLY UNDER 20 KNOTS SATURDAY AFTERNOON THROUGH SUNDAY BEFORE HIGH PRESSURE BRINGS LIGHT WINDS SUNDAY NIGHT INTO MONDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
141 PM EDT WED MAY 4 2016 .AVIATION... UPPER LOW AND SURFACE LOW WERE SPINNING OVER SOUTHWEST LOWER MICHIGAN THIS AFTERNOON AND WILL SLOWLY EXIT SOUTHEAST OVERNIGHT. IN THE MEANTIME SEVERAL BAND OF SHOWERS WERE SPIRALLING AROUND THESE LOWS ACROSS SOUTHEAST MI. THERE WERE EMBEDDED THUNDERSTORMS TOO. EXPECT THIS TO CONTINUE THROUGH THE AFTERNOON...BUT SHOW A DECREASE TOWARD 00Z AS BOTH THE LOWS SPIN AWAY AND INSTABILITY DECREASES. WINDS WILL BE STRONG ENOUGH AROUND THIS LOW EARLY...10 TO 15 KTS AND THE DIRECTION WILL BE DIFFICULT GIVEN THE LOW PASSING CLOSE TO THE DETROIT AREA TAFS. ALSO EXPECT SOME MVFR CEILINGS AND VISIBILITIES IN THE SHOWERS. SOME SHOWERS WILL LINGER INTO THE EVENING BUT BY 03Z ALL TAF SITES WILL BE DRY. CEILINGS FROM 4000 TO 6000 FEET EXPECTED THROUGH MUCH OF THE NIGHT. SOME SUGGESTION OF STRATUS WITH RECENT RAINS AND NORTHEAST FLOW OFF OF THE GREAT LAKES AND HAVE A TEMPO GROUP FOR THE NORTHERN TAF SITES AROUND DAYBREAK. THURSDAY WILL HAVE MORE DRYING WITH SCATTERED CUMULUS AND A NORTH WIND AROUND 10 KTS. FOR DTW...THUNDER THREAT HAS ALREADY ROTATED NORTH AND EAST OF DTW FOR THE AFTERNOON. STILL BANDS OF SHOWERS WILL MOVE IN FOR MVFR VISIBILITIES AND CEILING THROUGH THE AFTERNOON. AFTER 02Z SHOWERS END AND CEILINGS IMPROVE TO 4000 TO 6000 FEET AND BECOME SCATTERED BY DAYBREAK. //DTW THRESHOLD PROBABILITIES... * MEDIUM IN CEILINGS AT OR BELOW 5000 THROUGH 05Z. * LOW IN THUNDERSTORMS IMPACTING THE AREA THROUGH 21Z. && .PREV DISCUSSION...ISSUED 1236 PM EDT WED MAY 4 2016 UPDATE... WATER VAPOR IMAGERY INDICATES UPPER ENERGY IS STARTING TO CLOSE OFF OVER SOUTHWEST MICHIGAN AS PREDICTED BY NWP SUITE. THIS SHOULD PIVOT THE NORTH-SOUTH ORIENTATED BAND OF PRECIPITATION THAT WAS OVER WESTERN MICHIGAN THIS MORNING MORE INTO SOUTHEAST LOWER MICHIGAN AS CYCLONIC FLOW INCREASES AROUND THE SYSTEM AND THE DEFORMATION BAND TAKES ON A MORE NORTHWEST TO SOUTHEAST ORIENTATION. THIS IS ALREADY STARTING TO TAKE SHAPE PER LATEST RADAR IMAGERY. BAND OF HEAVIEST RAIN IS EXPECTED TO STRETCH ROUGHLY FROM THE SAGINAW VALLEY DOWN THROUGH THE DETROIT AREA THIS AFTERNOON BEFORE DROPPING SOUTH EARLY TONIGHT AS THE LOW CENTER WORKS SOUTHWARD. SOME MINOR ADJUSTMENTS WERE MADE TO PRECIPITATION PLACEMENT BASED ON RADAR TRENDS AND LATEST RUNS OF HIGHER-RES MODELS (HRRR...NAM12...NMM)...WITH HIGHEST POPS AND QPF SHIFTED VERY SLIGHTLY TO THE WEST AND SOUTH. BIGGEST CHANGES WERE IN THE FORM OF HIGHER POPS OVER LENAWEE COUNTY...LOWER POPS OVER THE THUMB...AND A MORE PRONOUNCED DRYING TREND OVER THE NORTHERN HALF OF THE FORECAST AREA EARLY TONIGHT. STRONGER SHOWERS AND THUNDERSTORMS HAVE ALSO STARTED TO DEVELOP EARLY THIS AFTERNOON AS WARMING OCCURS WITH DIURNAL HEATING IN THE LOW LEVELS AND THE UPPER LEVELS COOL IN THE PROXIMITY OF THE DEVELOPING UPPER LOW. THIS HAS RESULTED IN A FEW HUNDRED J/KG OF MU CAPE PER LATEST SPC ANALYSIS. STILL NOT EXPECTING SEVERE WEATHER...BUT LOCALLY HEAVY RAINFALL IS EXPECTED. PREV DISCUSSION...ISSUED 337 AM EDT WED MAY 4 2016 DISCUSSION... IMPRESSIVE SPREAD STILL EXISTS AMONG THE GUIDANCE THIS MORNING AS FORECAST LEAD TIME DIMINISHES TO ZERO. WATER VAPOR IMAGERY SHOWS A POWERFUL LEAD WAVE DIGGING INTO THE MIDWEST WITH A NEARLY EQUIVALENTLY STRONG TRAILING WAVE OVER WEST-CENTRAL WISCONSIN AT 07Z. THE TRAILING WAVE HAS BEEN POORLY RESOLVED BY MANY MEMBERS OF THE GUIDANCE...THE RAP APPEARING TO HANDLE IT THE BEST. EVEN SO, THE RAPID REFRESH IS STRUGGLING TO KEEP UP WITH 3-HOUR PRESSURE FALLS OF 3-5MB THIS MORNING. EXPANDING SHOWER COVERAGE IN ADVANCE OF THE WAVE IS OCCURRING WITHIN THE CORRIDOR OF MOISTURE TRANSPORT THAT HAS EMERGED OVER SOUTHWEST MICHIGAN DURING THE LAST COUPLE OF HOURS. FOR NOW, THIS ACTIVITY IS STRUGGLING TO PENETRATE THE CWA DUE TO ANTECEDENT DRY AIR EVIDENT ON THE 00Z DTX SOUNDING. COVERAGE IS EXPECTED TO INCREASE IN SE MICHIGAN OVER THE NEXT SEVERAL HOURS AS THE COLUMN SATURATES, LARGE SCALE FORCING INCREASES, AND DIURNAL DESTABILIZATION GETS UNDERWAY. THE PRIMARY FEATURE OF INTEREST, THE BAND OF RAIN WITH EMBEDDED HEAVY SHOWERS, IS SO FAR BEHAVING AS ANTICIPATED. ITS NARROW STRUCTURE IS ATTRIBUTABLE TO DEEP LAYER LINEAR/CONVERGENT FORCING ALONG THE STRONG TROUGH AXIS. THE UPPER TROUGH WILL BEGIN THE PROCESS OF CLOSING OFF LATE THIS MORNING OR EARLY THIS AFTERNOON AS ENERGY CONTINUES TO FLOOD SOUTH INTO THE WESTERN GREAT LAKES. AS THIS OCCURS, THE BAND WILL STALL AND PIVOT IN CYCLONIC FASHION WITH PRECIPITATION RATES INTENSIFYING AS DEFORMATION FORCING RAMPS UP WEST OF US-23. IN ADDITION, DIURNAL HEATING AND STEEP LAPSE RATES WILL CONTRIBUTE TO A LOW DENSITY CAPE PROFILE CHARACTERIZED BY A FEW HUNDRED J/KG OF POTENTIAL ENERGY. SKINNY CAPE WITHIN PERSISTENT STRONG DEFORMATION WILL BE SUFFICIENT TO PRODUCE A SOLID HALF INCH TO THREE QUARTERS OF RAIN OVER WESTERN AREAS. A LOCALIZED AREA - PERHAPS JUST THE FOOTPRINT OF A COUNTY OR TWO -COULD EASILY SEE OVER AN INCH IN THIS SETUP. MOST LIKELY AREA FOR HEAVIEST RAIN WILL BE BETWEEN LIVINGSTON AND BAY COUNTIES WEST OF US-23/I-75. THE LACK OF SIGNIFICANT MOISTURE (PWAT < 0.80") AND A VERY SHALLOW (< 5KFT) WARM CLOUD LAYER WILL PUT A DEFINITE CEILING ON POTENTIAL RAINFALL AMOUNTS SO THINGS WILL NOT GET OUT OF CONTROL. UNCERTAINTY IN PRECIP POTENTIAL INCREASES FOR EASTERN AREAS, INCLUDING DETROIT METRO, AS THE CONVERGENT RAINFALL BAND STALLS UPON THE MID-LEVEL LOW CLOSING OFF. HOWEVER, LATEST RAP SIMULATIONS SHOW RESPECTABLE CAPE OF A FEW HUNDRED J/KG ACROSS THE EAST. WILL LIKELY SEE SOME SUBTLE RIDGING FORCED OVER THE EASTERN CWA DURING PEAK HEATING, BUT LOW/MID-LEVEL THETA MAY BE JUST ENOUGH IN THE STEEP LAPSE RATE ENVIRONMENT TO SERVE AS A TRIGGER FOR DISORGANIZED SHOWER ACTIVITY DURING THE AFTERNOON. THUS, LIKELY POPS REMAIN IN PLACE IN SPITE OF THE WESTWARD ADJUSTMENT FROM YESTERDAY MORNING`S FORECAST. WARMING TREND INTO THE 60S THURSDAY AND LOW 70S FRIDAY AS RIDGING IS FORCED THROUGH THE CWA DURING THE LATE WEEK PERIOD. LINGERING CYCLONIC FLOW AND MOISTURE WILL KEEP A PARTIAL COVERAGE OF DIURNAL CU AND POSSIBLY JUST AN ISOLATED SHOWER IN THE FORECAST THROUGH THURSDAY. DEEP LAYER SUBSIDENCE WILL SUPPORT FULL SUN AND MUCH WARMER TEMPS ON FRIDAY AS THE BOUNDARY LAYER TAPS INTO 850MB TEMPS IN THE HIGH SINGLE DIGITS BY AFTERNOON. MARINE... MODEST NORTHERLY WINDS WILL BEGIN TO TAKE HOLD ACROSS THE CENTRAL GREAT LAKES TODAY AS LOW PRESSURE PIVOTS THROUGH LOWER MICHIGAN. SLIGHT INCREASE IN NORTHERLY FLOW TONIGHT INTO EARLY THURSDAY MAY LEAD TO A BRIEF PERIOD OF GUSTS NEAR 20 KNOTS ACROSS SOUTHERN SECTIONS OF LAKE HURON DURING THIS TIME. THE ONSHORE FLOW WILL ALSO BRING A PERIOD OF ELEVATED WAVE CONDITIONS ALONG THE THUMB DURING THIS TIME. HOWEVER SMALL CRAFT ADVISORY LEVEL CONDITIONS ARE CURRENTLY NOT ANTICIPATED. HIGH PRESSURE WILL THEN BRING TRANQUIL MARINE CONDITIONS FOR THE LATE WEEK PERIOD. HYDROLOGY... STRENGTHENING LOW PRESSURE WILL DROP SOUTHEAST ACROSS THE STATE THROUGH THIS EVENING. A PERIOD OF STRONG FORCING ASSOCIATED WITH THIS SYSTEM WILL SLIDE INTO WESTERN PORTIONS SE MICHIGAN LATE TODAY. THIS WILL FOCUS AN AXIS OF HEAVIER RAINFALL ALONG HIGHWAY 23 CORRIDOR...WHERE RAINFALL AMOUNTS FROM ONE HALF TO THREE QUARTERS OF AN INCH ARE EXPECTED. DECREASING RAINFALL AMOUNTS WITH EASTWARD EXTENT...LEAVING EASTERN PORTIONS OF METRO DETROIT NORTHWARD INTO THE THUMB WITH LESS THAN A QUARTER OF AN INCH. THE BULK OF THIS RAINFALL WILL OCCUR DURING THE AFTERNOON AND EARLY EVENING HOURS. RAINFALL WILL TAPER OFF QUICKLY EARLY TONIGHT WITH GENERALLY DRY WEATHER THURSDAY AND FRIDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....RBP UPDATE.......HLO DISCUSSION...JVC MARINE.......MR HYDROLOGY....MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1236 PM EDT WED MAY 4 2016 .UPDATE... WATER VAPOR IMAGERY INDICATES UPPER ENERGY IS STARTING TO CLOSE OFF OVER SOUTHWEST MICHIGAN AS PREDICTED BY NWP SUITE. THIS SHOULD PIVOT THE NORTH-SOUTH ORIENTATED BAND OF PRECIPITATION THAT WAS OVER WESTERN MICHIGAN THIS MORNING MORE INTO SOUTHEAST LOWER MICHIGAN AS CYCLONIC FLOW INCREASES AROUND THE SYSTEM AND THE DEFORMATION BAND TAKES ON A MORE NORTHWEST TO SOUTHEAST ORIENTATION. THIS IS ALREADY STARTING TO TAKE SHAPE PER LATEST RADAR IMAGERY. BAND OF HEAVIEST RAIN IS EXPECTED TO STRETCH ROUGHLY FROM THE SAGINAW VALLEY DOWN THROUGH THE DETROIT AREA THIS AFTERNOON BEFORE DROPPING SOUTH EARLY TONIGHT AS THE LOW CENTER WORKS SOUTHWARD. SOME MINOR ADJUSTMENTS WERE MADE TO PRECIPITATION PLACEMENT BASED ON RADAR TRENDS AND LATEST RUNS OF HIGHER-RES MODELS (HRRR...NAM12...NMM)...WITH HIGHEST POPS AND QPF SHIFTED VERY SLIGHTLY TO THE WEST AND SOUTH. BIGGEST CHANGES WERE IN THE FORM OF HIGHER POPS OVER LENAWEE COUNTY...LOWER POPS OVER THE THUMB...AND A MORE PRONOUNCED DRYING TREND OVER THE NORTHERN HALF OF THE FORECAST AREA EARLY TONIGHT. STRONGER SHOWERS AND THUNDERSTORMS HAVE ALSO STARTED TO DEVELOP EARLY THIS AFTERNOON AS WARMING OCCURS WITH DIURNAL HEATING IN THE LOW LEVELS AND THE UPPER LEVELS COOL IN THE PROXIMITY OF THE DEVELOPING UPPER LOW. THIS HAS RESULTED IN A FEW HUNDRED J/KG OF MU CAPE PER LATEST SPC ANALYSIS. STILL NOT EXPECTING SEVERE WEATHER...BUT LOCALLY HEAVY RAINFALL IS EXPECTED. && .AVIATION...ISSUED 709 AM EDT WED MAY 4 2016 STEADY STREAM OF MID LEVEL MOISTURE WILL SUSTAIN POCKETS OF SHOWERS WITHIN A HIGH BASED CLOUD THIS MORNING. SE MICHIGAN EXPECTED RESIDE ALONG THE EASTERN EXTENT OF THE DEEPER MOISTURE AND FORCING ASSOCIATED WITH LOW PRESSURE TRACKING THROUGH LOWER MICHIGAN. MBS/FNT REMAIN MORE FAVORABLY POSITIONED TO SEE A PERIOD OF WIDESPREAD PRECIPITATION THIS AFTERNOON WITH AN ACCOMPANYING REDUCTION IN CONDITIONS INTO MVFR...PERHAPS BRIEFLY IFR AT MBS. OVERALL TIMING A TOUCH SLOWER NOW...BUT WILL HOLD WITH THIS GENERAL TIMING. LESS CERTAINTY FROM PTK SOUTHWARD...BUT WITH GROWING CONFIDENCE THAT PREVAILING CONDITIONS WILL REMAIN IN VFR AS SHOWERS FILL IN. A WEAKLY UNSTABLE ENVIRONMENT MAY SUPPORT EMBEDDED THUNDER...UNCERTAINTY IN BOTH TIMING AND COVERAGE PRECLUDING A DEFINED MENTION. FOR DTW...MINIMALLY IMPACTFUL LIGHT SHOWERS IN CEILINGS ABOVE 5000 FT FOR THE MORNING PERIOD. METRO WILL THEN RESIDE AT THE EASTERN EDGE OF MORE ORGANIZED PRECIPITATION /AND POSSIBLE THUNDER/ EXPECTED TO DEVELOP BY MID-LATE AFTERNOON. EXISTING DRY LOW LEVEL ENVIRONMENT MAY PROVE A FORMIDABLE LIMITING FACTOR IN GREATER DEVELOPMENT LOCALLY. THIS CONTINUES TO LEND SUPPORT TOWARD A MORE OPTIMISTIC OUTLOOK ON CEILING/VISIBILITY TRENDS DURING THIS TIME. //DTW THRESHOLD PROBABILITIES... * LOW IN CEILINGS AT OR BELOW 5000 FT PRIOR TO 20Z...MEDIUM FROM MID AFTERNOON INTO THE EVENING. * LOW IN THUNDERSTORMS IMPACTING THE AREA TODAY. && .PREV DISCUSSION...ISSUED 337 AM EDT WED MAY 4 2016 DISCUSSION... IMPRESSIVE SPREAD STILL EXISTS AMONG THE GUIDANCE THIS MORNING AS FORECAST LEAD TIME DIMINISHES TO ZERO. WATER VAPOR IMAGERY SHOWS A POWERFUL LEAD WAVE DIGGING INTO THE MIDWEST WITH A NEARLY EQUIVALENTLY STRONG TRAILING WAVE OVER WEST-CENTRAL WISCONSIN AT 07Z. THE TRAILING WAVE HAS BEEN POORLY RESOLVED BY MANY MEMBERS OF THE GUIDANCE...THE RAP APPEARING TO HANDLE IT THE BEST. EVEN SO, THE RAPID REFRESH IS STRUGGLING TO KEEP UP WITH 3-HOUR PRESSURE FALLS OF 3-5MB THIS MORNING. EXPANDING SHOWER COVERAGE IN ADVANCE OF THE WAVE IS OCCURRING WITHIN THE CORRIDOR OF MOISTURE TRANSPORT THAT HAS EMERGED OVER SOUTHWEST MICHIGAN DURING THE LAST COUPLE OF HOURS. FOR NOW, THIS ACTIVITY IS STRUGGLING TO PENETRATE THE CWA DUE TO ANTECEDENT DRY AIR EVIDENT ON THE 00Z DTX SOUNDING. COVERAGE IS EXPECTED TO INCREASE IN SE MICHIGAN OVER THE NEXT SEVERAL HOURS AS THE COLUMN SATURATES, LARGE SCALE FORCING INCREASES, AND DIURNAL DESTABILIZATION GETS UNDERWAY. THE PRIMARY FEATURE OF INTEREST, THE BAND OF RAIN WITH EMBEDDED HEAVY SHOWERS, IS SO FAR BEHAVING AS ANTICIPATED. ITS NARROW STRUCTURE IS ATTRIBUTABLE TO DEEP LAYER LINEAR/CONVERGENT FORCING ALONG THE STRONG TROUGH AXIS. THE UPPER TROUGH WILL BEGIN THE PROCESS OF CLOSING OFF LATE THIS MORNING OR EARLY THIS AFTERNOON AS ENERGY CONTINUES TO FLOOD SOUTH INTO THE WESTERN GREAT LAKES. AS THIS OCCURS, THE BAND WILL STALL AND PIVOT IN CYCLONIC FASHION WITH PRECIPITATION RATES INTENSIFYING AS DEFORMATION FORCING RAMPS UP WEST OF US-23. IN ADDITION, DIURNAL HEATING AND STEEP LAPSE RATES WILL CONTRIBUTE TO A LOW DENSITY CAPE PROFILE CHARACTERIZED BY A FEW HUNDRED J/KG OF POTENTIAL ENERGY. SKINNY CAPE WITHIN PERSISTENT STRONG DEFORMATION WILL BE SUFFICIENT TO PRODUCE A SOLID HALF INCH TO THREE QUARTERS OF RAIN OVER WESTERN AREAS. A LOCALIZED AREA - PERHAPS JUST THE FOOTPRINT OF A COUNTY OR TWO -COULD EASILY SEE OVER AN INCH IN THIS SETUP. MOST LIKELY AREA FOR HEAVIEST RAIN WILL BE BETWEEN LIVINGSTON AND BAY COUNTIES WEST OF US-23/I-75. THE LACK OF SIGNIFICANT MOISTURE (PWAT < 0.80") AND A VERY SHALLOW (< 5KFT) WARM CLOUD LAYER WILL PUT A DEFINITE CEILING ON POTENTIAL RAINFALL AMOUNTS SO THINGS WILL NOT GET OUT OF CONTROL. UNCERTAINTY IN PRECIP POTENTIAL INCREASES FOR EASTERN AREAS, INCLUDING DETROIT METRO, AS THE CONVERGENT RAINFALL BAND STALLS UPON THE MID-LEVEL LOW CLOSING OFF. HOWEVER, LATEST RAP SIMULATIONS SHOW RESPECTABLE CAPE OF A FEW HUNDRED J/KG ACROSS THE EAST. WILL LIKELY SEE SOME SUBTLE RIDGING FORCED OVER THE EASTERN CWA DURING PEAK HEATING, BUT LOW/MID-LEVEL THETA MAY BE JUST ENOUGH IN THE STEEP LAPSE RATE ENVIRONMENT TO SERVE AS A TRIGGER FOR DISORGANIZED SHOWER ACTIVITY DURING THE AFTERNOON. THUS, LIKELY POPS REMAIN IN PLACE IN SPITE OF THE WESTWARD ADJUSTMENT FROM YESTERDAY MORNING`S FORECAST. WARMING TREND INTO THE 60S THURSDAY AND LOW 70S FRIDAY AS RIDGING IS FORCED THROUGH THE CWA DURING THE LATE WEEK PERIOD. LINGERING CYCLONIC FLOW AND MOISTURE WILL KEEP A PARTIAL COVERAGE OF DIURNAL CU AND POSSIBLY JUST AN ISOLATED SHOWER IN THE FORECAST THROUGH THURSDAY. DEEP LAYER SUBSIDENCE WILL SUPPORT FULL SUN AND MUCH WARMER TEMPS ON FRIDAY AS THE BOUNDARY LAYER TAPS INTO 850MB TEMPS IN THE HIGH SINGLE DIGITS BY AFTERNOON. MARINE... MODEST NORTHERLY WINDS WILL BEGIN TO TAKE HOLD ACROSS THE CENTRAL GREAT LAKES TODAY AS LOW PRESSURE PIVOTS THROUGH LOWER MICHIGAN. SLIGHT INCREASE IN NORTHERLY FLOW TONIGHT INTO EARLY THURSDAY MAY LEAD TO A BRIEF PERIOD OF GUSTS NEAR 20 KNOTS ACROSS SOUTHERN SECTIONS OF LAKE HURON DURING THIS TIME. THE ONSHORE FLOW WILL ALSO BRING A PERIOD OF ELEVATED WAVE CONDITIONS ALONG THE THUMB DURING THIS TIME. HOWEVER SMALL CRAFT ADVISORY LEVEL CONDITIONS ARE CURRENTLY NOT ANTICIPATED. HIGH PRESSURE WILL THEN BRING TRANQUIL MARINE CONDITIONS FOR THE LATE WEEK PERIOD. HYDROLOGY... STRENGTHENING LOW PRESSURE WILL DROP SOUTHEAST ACROSS THE STATE THROUGH THIS EVENING. A PERIOD OF STRONG FORCING ASSOCIATED WITH THIS SYSTEM WILL SLIDE INTO WESTERN PORTIONS SE MICHIGAN LATE TODAY. THIS WILL FOCUS AN AXIS OF HEAVIER RAINFALL ALONG HIGHWAY 23 CORRIDOR...WHERE RAINFALL AMOUNTS FROM ONE HALF TO THREE QUARTERS OF AN INCH ARE EXPECTED. DECREASING RAINFALL AMOUNTS WITH EASTWARD EXTENT...LEAVING EASTERN PORTIONS OF METRO DETROIT NORTHWARD INTO THE THUMB WITH LESS THAN A QUARTER OF AN INCH. THE BULK OF THIS RAINFALL WILL OCCUR DURING THE AFTERNOON AND EARLY EVENING HOURS. RAINFALL WILL TAPER OFF QUICKLY EARLY TONIGHT WITH GENERALLY DRY WEATHER THURSDAY AND FRIDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......HLO AVIATION.....MR DISCUSSION...JVC MARINE.......MR HYDROLOGY....MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
709 AM EDT WED MAY 4 2016 .AVIATION... STEADY STREAM OF MID LEVEL MOISTURE WILL SUSTAIN POCKETS OF SHOWERS WITHIN A HIGH BASED CLOUD THIS MORNING. SE MICHIGAN EXPECTED RESIDE ALONG THE EASTERN EXTENT OF THE DEEPER MOISTURE AND FORCING ASSOCIATED WITH LOW PRESSURE TRACKING THROUGH LOWER MICHIGAN. MBS/FNT REMAIN MORE FAVORABLY POSITIONED TO SEE A PERIOD OF WIDESPREAD PRECIPITATION THIS AFTERNOON WITH AN ACCOMPANYING REDUCTION IN CONDITIONS INTO MVFR...PERHAPS BRIEFLY IFR AT MBS. OVERALL TIMING A TOUCH SLOWER NOW...BUT WILL HOLD WITH THIS GENERAL TIMING. LESS CERTAINTY FROM PTK SOUTHWARD...BUT WITH GROWING CONFIDENCE THAT PREVAILING CONDITIONS WILL REMAIN IN VFR AS SHOWERS FILL IN. A WEAKLY UNSTABLE ENVIRONMENT MAY SUPPORT EMBEDDED THUNDER...UNCERTAINTY IN BOTH TIMING AND COVERAGE PRECLUDING A DEFINED MENTION. FOR DTW...MINIMALLY IMPACTFUL LIGHT SHOWERS IN CEILINGS ABOVE 5000 FT FOR THE MORNING PERIOD. METRO WILL THEN RESIDE AT THE EASTERN EDGE OF MORE ORGANIZED PRECIPITATION /AND POSSIBLE THUNDER/ EXPECTED TO DEVELOP BY MID-LATE AFTERNOON. EXISTING DRY LOW LEVEL ENVIRNMENT MAY PROVE A FORMIDABLE LIMITING FACTOR IN GREATER DEVELOPMENT LOCALLY. THIS CONTINUES TO LEND SUPPORT TOWARD A MORE OPTIMISTIC OUTLOOK ON CEILING/VISIBILITY TRENDS DURING THIS TIME. //DTW THRESHOLD PROBABILITIES... * LOW IN CEILINGS AT OR BELOW 5000 FT PRIOR TO 20Z...MEDIUM FROM MID AFTERNOON INTO THE EVENING. * LOW IN THUNDERSTORMS IMPACTING THE AREA TODAY. && .PREV DISCUSSION...ISSUED 337 AM EDT WED MAY 4 2016 DISCUSSION... IMPRESSIVE SPREAD STILL EXISTS AMONG THE GUIDANCE THIS MORNING AS FORECAST LEAD TIME DIMINISHES TO ZERO. WATER VAPOR IMAGERY SHOWS A POWERFUL LEAD WAVE DIGGING INTO THE MIDWEST WITH A NEARLY EQUIVALENTLY STRONG TRAILING WAVE OVER WEST-CENTRAL WISCONSIN AT 07Z. THE TRAILING WAVE HAS BEEN POORLY RESOLVED BY MANY MEMBERS OF THE GUIDANCE...THE RAP APPEARING TO HANDLE IT THE BEST. EVEN SO, THE RAPID REFRESH IS STRUGGLING TO KEEP UP WITH 3-HOUR PRESSURE FALLS OF 3-5MB THIS MORNING. EXPANDING SHOWER COVERAGE IN ADVANCE OF THE WAVE IS OCCURRING WITHIN THE CORRIDOR OF MOISTURE TRANSPORT THAT HAS EMERGED OVER SOUTHWEST MICHIGAN DURING THE LAST COUPLE OF HOURS. FOR NOW, THIS ACTIVITY IS STRUGGLING TO PENETRATE THE CWA DUE TO ANTECEDENT DRY AIR EVIDENT ON THE 00Z DTX SOUNDING. COVERAGE IS EXPECTED TO INCREASE IN SE MICHIGAN OVER THE NEXT SEVERAL HOURS AS THE COLUMN SATURATES, LARGE SCALE FORCING INCREASES, AND DIURNAL DESTABILIZATION GETS UNDERWAY. THE PRIMARY FEATURE OF INTEREST, THE BAND OF RAIN WITH EMBEDDED HEAVY SHOWERS, IS SO FAR BEHAVING AS ANTICIPATED. ITS NARROW STRUCTURE IS ATTRIBUTABLE TO DEEP LAYER LINEAR/CONVERGENT FORCING ALONG THE STRONG TROUGH AXIS. THE UPPER TROUGH WILL BEGIN THE PROCESS OF CLOSING OFF LATE THIS MORNING OR EARLY THIS AFTERNOON AS ENERGY CONTINUES TO FLOOD SOUTH INTO THE WESTERN GREAT LAKES. AS THIS OCCURS, THE BAND WILL STALL AND PIVOT IN CYCLONIC FASHION WITH PRECIPITATION RATES INTENSIFYING AS DEFORMATION FORCING RAMPS UP WEST OF US-23. IN ADDITION, DIURNAL HEATING AND STEEP LAPSE RATES WILL CONTRIBUTE TO A LOW DENSITY CAPE PROFILE CHARACTERIZED BY A FEW HUNDRED J/KG OF POTENTIAL ENERGY. SKINNY CAPE WITHIN PERSISTENT STRONG DEFORMATION WILL BE SUFFICIENT TO PRODUCE A SOLID HALF INCH TO THREE QUARTERS OF RAIN OVER WESTERN AREAS. A LOCALIZED AREA - PERHAPS JUST THE FOOTPRINT OF A COUNTY OR TWO -COULD EASILY SEE OVER AN INCH IN THIS SETUP. MOST LIKELY AREA FOR HEAVIEST RAIN WILL BE BETWEEN LIVINGSTON AND BAY COUNTIES WEST OF US-23/I-75. THE LACK OF SIGNIFICANT MOISTURE (PWAT < 0.80") AND A VERY SHALLOW (< 5KFT) WARM CLOUD LAYER WILL PUT A DEFINITE CEILING ON POTENTIAL RAINFALL AMOUNTS SO THINGS WILL NOT GET OUT OF CONTROL. UNCERTAINTY IN PRECIP POTENTIAL INCREASES FOR EASTERN AREAS, INCLUDING DETROIT METRO, AS THE CONVERGENT RAINFALL BAND STALLS UPON THE MID-LEVEL LOW CLOSING OFF. HOWEVER, LATEST RAP SIMULATIONS SHOW RESPECTABLE CAPE OF A FEW HUNDRED J/KG ACROSS THE EAST. WILL LIKELY SEE SOME SUBTLE RIDGING FORCED OVER THE EASTERN CWA DURING PEAK HEATING, BUT LOW/MID-LEVEL THETA MAY BE JUST ENOUGH IN THE STEEP LAPSE RATE ENVIRONMENT TO SERVE AS A TRIGGER FOR DISORGANIZED SHOWER ACTIVITY DURING THE AFTERNOON. THUS, LIKELY POPS REMAIN IN PLACE IN SPITE OF THE WESTWARD ADJUSTMENT FROM YESTERDAY MORNING`S FORECAST. WARMING TREND INTO THE 60S THURSDAY AND LOW 70S FRIDAY AS RIDGING IS FORCED THROUGH THE CWA DURING THE LATE WEEK PERIOD. LINGERING CYCLONIC FLOW AND MOISTURE WILL KEEP A PARTIAL COVERAGE OF DIURNAL CU AND POSSIBLY JUST AN ISOLATED SHOWER IN THE FORECAST THROUGH THURSDAY. DEEP LAYER SUBSIDENCE WILL SUPPORT FULL SUN AND MUCH WARMER TEMPS ON FRIDAY AS THE BOUNDARY LAYER TAPS INTO 850MB TEMPS IN THE HIGH SINGLE DIGITS BY AFTERNOON. MARINE... MODEST NORTHERLY WINDS WILL BEGIN TO TAKE HOLD ACROSS THE CENTRAL GREAT LAKES TODAY AS LOW PRESSURE PIVOTS THROUGH LOWER MICHIGAN. SLIGHT INCREASE IN NORTHERLY FLOW TONIGHT INTO EARLY THURSDAY MAY LEAD TO A BRIEF PERIOD OF GUSTS NEAR 20 KNOTS ACROSS SOUTHERN SECTIONS OF LAKE HURON DURING THIS TIME. THE ONSHORE FLOW WILL ALSO BRING A PERIOD OF ELEVATED WAVE CONDITIONS ALONG THE THUMB DURING THIS TIME. HOWEVER SMALL CRAFT ADVISORY LEVEL CONDITIONS ARE CURRENTLY NOT ANTICIPATED. HIGH PRESSURE WILL THEN BRING TRANQUIL MARINE CONDITIONS FOR THE LATE WEEK PERIOD. HYDROLOGY... STRENGTHENING LOW PRESSURE WILL DROP SOUTHEAST ACROSS THE STATE THROUGH THIS EVENING. A PERIOD OF STRONG FORCING ASSOCIATED WITH THIS SYSTEM WILL SLIDE INTO WESTERN PORTIONS SE MICHIGAN LATE TODAY. THIS WILL FOCUS AN AXIS OF HEAVIER RAINFALL ALONG HIGHWAY 23 CORRIDOR...WHERE RAINFALL AMOUNTS FROM ONE HALF TO THREE QUARTERS OF AN INCH ARE EXPECTED. DECREASING RAINFALL AMOUNTS WITH EASTWARD EXTENT...LEAVING EASTERN PORTIONS OF METRO DETROIT NORTHWARD INTO THE THUMB WITH LESS THAN A QUARTER OF AN INCH. THE BULK OF THIS RAINFALL WILL OCCUR DURING THE AFTERNOON AND EARLY EVENING HOURS. RAINFALL WILL TAPER OFF QUICKLY EARLY TONIGHT WITH GENERALLY DRY WEATHER THURSDAY AND FRIDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....MR DISCUSSION...JVC MARINE.......MR HYDROLOGY....MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
337 AM EDT WED MAY 4 2016 .DISCUSSION... IMPRESSIVE SPREAD STILL EXISTS AMONG THE GUIDANCE THIS MORNING AS FORECAST LEAD TIME DIMINISHES TO ZERO. WATER VAPOR IMAGERY SHOWS A POWERFUL LEAD WAVE DIGGING INTO THE MIDWEST WITH A NEARLY EQUIVALENTLY STRONG TRAILING WAVE OVER WEST-CENTRAL WISCONSIN AT 07Z. THE TRAILING WAVE HAS BEEN POORLY RESOLVED BY MANY MEMBERS OF THE GUIDANCE...THE RAP APPEARING TO HANDLE IT THE BEST. EVEN SO, THE RAPID REFRESH IS STRUGGLING TO KEEP UP WITH 3-HOUR PRESSURE FALLS OF 3-5MB THIS MORNING. EXPANDING SHOWER COVERAGE IN ADVANCE OF THE WAVE IS OCCURRING WITHIN THE CORRIDOR OF MOISTURE TRANSPORT THAT HAS EMERGED OVER SOUTHWEST MICHIGAN DURING THE LAST COUPLE OF HOURS. FOR NOW, THIS ACTIVITY IS STRUGGLING TO PENETRATE THE CWA DUE TO ANTECEDENT DRY AIR EVIDENT ON THE 00Z DTX SOUNDING. COVERAGE IS EXPECTED TO INCREASE IN SE MICHIGAN OVER THE NEXT SEVERAL HOURS AS THE COLUMN SATURATES, LARGE SCALE FORCING INCREASES, AND DIURNAL DESTABILIZATION GETS UNDERWAY. THE PRIMARY FEATURE OF INTEREST, THE BAND OF RAIN WITH EMBEDDED HEAVY SHOWERS, IS SO FAR BEHAVING AS ANTICIPATED. ITS NARROW STRUCTURE IS ATTRIBUTABLE TO DEEP LAYER LINEAR/CONVERGENT FORCING ALONG THE STRONG TROUGH AXIS. THE UPPER TROUGH WILL BEGIN THE PROCESS OF CLOSING OFF LATE THIS MORNING OR EARLY THIS AFTERNOON AS ENERGY CONTINUES TO FLOOD SOUTH INTO THE WESTERN GREAT LAKES. AS THIS OCCURS, THE BAND WILL STALL AND PIVOT IN CYCLONIC FASHION WITH PRECIPITATION RATES INTENSIFYING AS DEFORMATION FORCING RAMPS UP WEST OF US-23. IN ADDITION, DIURNAL HEATING AND STEEP LAPSE RATES WILL CONTRIBUTE TO A LOW DENSITY CAPE PROFILE CHARACTERIZED BY A FEW HUNDRED J/KG OF POTENTIAL ENERGY. SKINNY CAPE WITHIN PERSISTENT STRONG DEFORMATION WILL BE SUFFICIENT TO PRODUCE A SOLID HALF INCH TO THREE QUARTERS OF RAIN OVER WESTERN AREAS. A LOCALIZED AREA - PERHAPS JUST THE FOOTPRINT OF A COUNTY OR TWO -COULD EASILY SEE OVER AN INCH IN THIS SETUP. MOST LIKELY AREA FOR HEAVIEST RAIN WILL BE BETWEEN LIVINGSTON AND BAY COUNTIES WEST OF US-23/I-75. THE LACK OF SIGNIFICANT MOISTURE (PWAT < 0.80") AND A VERY SHALLOW (< 5KFT) WARM CLOUD LAYER WILL PUT A DEFINITE CEILING ON POTENTIAL RAINFALL AMOUNTS SO THINGS WILL NOT GET OUT OF CONTROL. UNCERTAINTY IN PRECIP POTENTIAL INCREASES FOR EASTERN AREAS, INCLUDING DETROIT METRO, AS THE CONVERGENT RAINFALL BAND STALLS UPON THE MID-LEVEL LOW CLOSING OFF. HOWEVER, LATEST RAP SIMULATIONS SHOW RESPECTABLE CAPE OF A FEW HUNDRED J/KG ACROSS THE EAST. WILL LIKELY SEE SOME SUBTLE RIDGING FORCED OVER THE EASTERN CWA DURING PEAK HEATING, BUT LOW/MID-LEVEL THETA MAY BE JUST ENOUGH IN THE STEEP LAPSE RATE ENVIRONMENT TO SERVE AS A TRIGGER FOR DISORGANIZED SHOWER ACTIVITY DURING THE AFTERNOON. THUS, LIKELY POPS REMAIN IN PLACE IN SPITE OF THE WESTWARD ADJUSTMENT FROM YESTERDAY MORNING`S FORECAST. WARMING TREND INTO THE 60S THURSDAY AND LOW 70S FRIDAY AS RIDGING IS FORCED THROUGH THE CWA DURING THE LATE WEEK PERIOD. LINGERING CYCLONIC FLOW AND MOISTURE WILL KEEP A PARTIAL COVERAGE OF DIURNAL CU AND POSSIBLY JUST AN ISOLATED SHOWER IN THE FORECAST THROUGH THURSDAY. DEEP LAYER SUBSIDENCE WILL SUPPORT FULL SUN AND MUCH WARMER TEMPS ON FRIDAY AS THE BOUNDARY LAYER TAPS INTO 850MB TEMPS IN THE HIGH SINGLE DIGITS BY AFTERNOON. && .MARINE... MODEST NORTHERLY WINDS WILL BEGIN TO TAKE HOLD ACROSS THE CENTRAL GREAT LAKES TODAY AS LOW PRESSURE PIVOTS THROUGH LOWER MICHIGAN. SLIGHT INCREASE IN NORTHERLY FLOW TONIGHT INTO EARLY THURSDAY MAY LEAD TO A BRIEF PERIOD OF GUSTS NEAR 20 KNOTS ACROSS SOUTHERN SECTIONS OF LAKE HURON DURING THIS TIME. THE ONSHORE FLOW WILL ALSO BRING A PERIOD OF ELEVATED WAVE CONDITIONS ALONG THE THUMB DURING THIS TIME. HOWEVER SMALL CRAFT ADVISORY LEVEL CONDITIONS ARE CURRENTLY NOT ANTICIPATED. HIGH PRESSURE WILL THEN BRING TRANQUIL MARINE CONDITIONS FOR THE LATE WEEK PERIOD. && .HYDROLOGY... STRENGTHENING LOW PRESSURE WILL DROP SOUTHEAST ACROSS THE STATE THROUGH THIS EVENING. A PERIOD OF STRONG FORCING ASSOCIATED WITH THIS SYSTEM WILL SLIDE INTO WESTERN PORTIONS SE MICHIGAN LATE TODAY. THIS WILL FOCUS AN AXIS OF HEAVIER RAINFALL ALONG HIGHWAY 23 CORRIDOR...WHERE RAINFALL AMOUNTS FROM ONE HALF TO THREE QUARTERS OF AN INCH ARE EXPECTED. DECREASING RAINFALL AMOUNTS WITH EASTWARD EXTENT...LEAVING EASTERN PORTIONS OF METRO DETROIT NORTHWARD INTO THE THUMB WITH LESS THAN A QUARTER OF AN INCH. THE BULK OF THIS RAINFALL WILL OCCUR DURING THE AFTERNOON AND EARLY EVENING HOURS. RAINFALL WILL TAPER OFF QUICKLY EARLY TONIGHT WITH GENERALLY DRY WEATHER THURSDAY AND FRIDAY. && .AVIATION...ISSUED 1154 PM EDT TUE MAY 3 2016 A REGION OF RAIN WILL SLOWLY PUSH TOWARD THE EAST DURING THE EARLY MORNING. MID LEVEL MOISTURE ADVECTION IN ADVANCE OF THE MAIN REGION OF RAIN MAY TRIGGER SOME BRIEF HIGH BASED LIGHT SHOWERS PRIOR TO DAYBREAK. RECENT MODEL GUIDANCE SUGGESTS THE MAIN REGION OF RAIN WILL WORK INTO MBS AND FNT JUST PRIOR TO DAYBREAK. WITH THE UPPER WAVE FORECAST TO DEVELOP INTO A CLOSED MID LEVEL LOW OVER NRN INDIANA ON WEDNESDAY...THE AXIS OF STRONGER FORCING WILL STRUGGLE TO PUSH MUCH FARTHER EAST THAN FNT AND PERHAPS PTK. INITIAL DRY AIR IN THE LOW LEVELS WILL LEAD TO A RATHER GRADUAL LOWERING OF CEILING HEIGHTS DURING THE COURSE OF THE MORNING. SOME DEGREE OF MVFR TYPE CIGS ARE EXPECTED AT FNT AND MBS BY AFTERNOON. DEVELOPING SFC LOW PRESSURE FORECAST TO TRACK SOUTH OF THE REGION WED AFTERNOON WILL DRAW A LITTLE COOLER LOW LEVEL AIR INTO FNT AND MBS...OFFERING A GOOD CHANCE OF LOW END MVFR AND/OR IFR CIGS LATE WED AFTERNOON/EVENING. A PERSISTENT INFLUX OF LOW LEVEL DRY AIR FARTHER EAST MAY IN FACT LEAD TO A RATHER NARROW REGION BETWEEN IFR/MVFR CONDITIONS AND VFR CONDITIONS. FOR DTW...RECENT RADAR IMAGERY IS SUGGESTING THE SCATTERED HIGH BASED SHOWERS WILL IMPACT METRO DETROIT DURING AT LEAST THE FIRST TWO TO FOUR HOURS OF THE TAF PERIOD. OTHERWISE...RECENT MODEL TRENDS SUGGEST DRIER LOW LEVEL AIR GETTING ADVECTED INTO METRO DETROIT FROM THE EAST ON WEDNESDAY AS THE SFC LOW DEVELOPS TO THE SOUTHWEST. THIS MAY HOLD THE MORE WIDESPREAD RAIN AND LOWER CEILINGS WEST OF METRO AIRPORT. //DTW THRESHOLD PROBABILITIES... * LOW IN CEILINGS AT OR BELOW 5000 FT THIS MORNING. MEDIUM THIS AFTERNOON. * LOW IN THUNDERSTORMS IMPACTING THE AREA TODAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ DISCUSSION...JVC MARINE.......MR HYDROLOGY....MR AVIATION.....SC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
135 AM EDT WED MAY 4 2016 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 416 PM EDT TUE MAY 3 2016 WV IMAGERY AND RAP ANALYSIS INDICATED A PROMINENT MID/UPPER LEVEL RIDGE FROM THE RODCKIES NORTHWARD THROUGH WRN CANADA RESULTING IN NNW FLOW FROM MANITOBA INTO THE UPPER MS VALEY AND WRN LAKES. AT THE SFC...A COLD FRONT EXTENDED INTO NW LAKE SUPERIOR FROM LOW PRES JUST WEST OF JAMES BAY. A VIGOROUS SHORTWAVE TROUGH INTO WRN LAKE SUPERIOR AND ASSOCIATED 800-600 MB FGEN IN ADVANCE OF THIS FEATURE SUPPORTED AN AREA OF SHOWERS THROUGH MOST OF UPPER MI. SOME ISOLD TSRA HAD ALSO DEVELOPED NEAR CYQT WHERE LOW LEVEL CONV WAS STRONGEST ALONG THE COLD FRONT. TONIGHT...EXPECT THE SHOWERS TO BECOME MORE SCATTERED LATE THIS AFTERNOON AND EVENING AS THE FGEN AREA SLIDES TO THE SE AND THE COLD FRONT MOVES IN. SOME ISOLD TSRA WILL ALSO STILL BE POSSIBLE WITH THE FRONT. CAA WILL INCREASE BEHIND THE FRONT LATE THIS EVENING INTO THE OVERNIGHT HOURS WITH INCREASED MIXING AND GUSTIER NORTH WINDS. EXPECT THE BEST CHANCE FOR PCPN LATE TONIGHT WHERE NRLY UPSLOPE FLOW IS STRONGEST OVER THE N CNTRL UPPER MI. AS WET BULB ZERO HEIGHTS DROP AFTER 06Z...SOME LIGHT SNOW MAY MIX IN WITH THE RAIN. WITH LOWS ONLY TO AROUND 34...ANY ACCUMULATION WOULD BE CONFINED MAINLY TO GRASSY SURFACES. WEDNESDAY...THE MID LEVEL TROUGH WILL CONTINUE TO DEEPEN INTO IN/OH KEEPING COLD NRLY FLOW GOING INTO UPPER MI. EXPECT ENOUGH DEEP MOISTURE TO LINGER WITH SATURATION NEAR -8C TO -10C LAYER TO MINIMIZE DZ CHANCES. SO...UPSLOPE SOME SN/RA IS EXPECTED TO CONTINUE INTO N CNTRL UPPER MI IN THE MORNING WITH POTENTIAL TO TRANSITION TO SOME DZ BY AFTERNOON AS THE 850-600 MOISTURE DEPARTS. WELL BELOW NORMAL TEMPS WILL PREVAIL WITH HIGHS FROM AROUND 50 NORTH TO 50 SOUTH EVEN AS SUNSHINE INCREASES IN THE AFTERNOON. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 329 PM EDT TUE MAY 3 2016 DEEP TROUGH OVER THE GREAT LAKES AND OHIO VALLEY GIVES WAY TO RISING HEIGHTS THU INTO FRI AS RIDGE OVER THE WESTERN CONUS MOVES EAST. SFC HIGH MOVES ACROSS UPPER GREAT LAKES WITH DRY WEATHER. BLO FREEZING TEMPS LIKELY OVER INTERIOR WEST BENEATH RIDGE AXIS ON WED NIGHT. ONCE THE SFC RIDGE MOVES EAST...WEAK SFC LOW OVER CANADIAN PRAIRIES WILL EXTEND A WARM FRONT TOWARD UPPER GREAT LAKES ON FRIDAY. WILL BEGIN TO WARM AWAY FM THE GREAT LAKES ON THU WITH READINGS INTO THE MID TO UPR 60S INTERIOR WEST. MIN RH WILL DROP BLO 30 PCT...BUT WINDS LOOK LIGHT. SCT-BKN MID CLOUDS IN THE MORNING SHOULD GIVE WAY TO MOSTLY SUNNY SKIES IN THE AFTN. DEEPER MIXING AND H85 TEMPS 14- 16C WILL PUSH TEMPS WELL ABOVE NORMAL INTO THE MID 70S TO MID 80S. DESPITE THE WARMTH...FIRE WEATHER ISSUES SHOULD BE MINIMAL AS SFC- H85 DWPNTS WILL BE ON THE RISE SO MIN RH SHOULD BE HIGHER THAN THU AND LIKE THU THE WINDS SHOULD BE LIGHT. SUMMERTIME WARMTH WILL BE SHORT LIVED AS STRONGER SHORTWAVE TROUGH CRASHES THE RIDGE OVER THE UPPER GREAT LAKES FRI NIGHT INTO SAT. COLD FRONT MOVES THROUGH FRI NIGHT. BROKEN BAND OF SHOWERS EXPECTED WITH THE FROPA. OUTSIDE CHANCE OF TSRA WITH DIFFLUENT FLOW ALOFT AND WEAK ELEVATED INSTABILITY /H7-H5 LAPSE RATES CONDITIONALY UNSTABLE AT 6.5C/KM AND MUCAPE UP TO 250 J/KG/...BUT SINCE STRONGEST PVA AND STRONGER WINDS ALOFT REMAIN OVER NORTHERN ONTARIO DO NOT EXPECT STRONG TSRA. BEHIND THE FRONT ON SAT...MUCH COOLER CONDITIONS BUT MOSTLY DRY. GUSTY NNW WINDS 20-30 MPH NEAR LK SUPERIOR AND UP TO 20 MPH INLAND. IF WATER TEMPS WERE WARMER ON LK SUPERIOR SETUP WOULD BE FAVORABLE FOR INCREASED SWIM RISK. CURRENT WATER TEMPS AROUND 40 IN THE NEARSHORE SO NOT AN ISSUE QUITE YET. WARMING TREND THROUGH REST OF EXTENDED /DAYTIME HIGHS 60S AND MAYBE SLIGHTLY WARMER/ AS UPPER TROUGH MOVING FROM SOUTHWEST CONUS TO NORTHERN PLAINS PUSHES RIDGE DOWNSTREAM OVER GREAT LAKES. DIFFERENCES ARISE MON INTO TUE ON HOW QUICK UPPER TROUGH BRINGS SFC LOW ACROSS THE CENTRAL TO NORTHERN PLAINS. GFS IS QUICKEST WHILE GEM IS MORE SUPPRESSED TO THE SOUTH. ECMWF IS A COMPROMISE. REGARDLESS...WEATHER DOES NOT APPEAR TOO HIGH IMPACT AS EVEN WITH GFS IDEA BULK OF HIGHER INSTABILITY BOTH SFC AND ELEVATED REMAINS TOO FAR SW TO BRING ANY STRONGER TSRA AS FAR NORTH AS UPR MICHIGAN. CURRENT FORECAST FOR TUE SHOWS MORE CLOUDS AND SHRA/TSRA CHANCES ATTM...BUT IF THE SLOWER IDEA WORKS OUT...DRY WEATHER WOULD HOLD UNTIL LATE TUE AND TUE WOULD BECOME MORE OF A FIRE WEATHER ISSUE WITH TEMPS NEAR 70 DEGREES...LOW RH VALUES AND GUSTY EAST-SOUTHEAST WINDS AHEAD OF THE LOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 132 AM EDT WED MAY 4 2016 COLDER AIR AND LOW-LEVEL MOISTURE BEHIND A COLD FRONT WILL LEAD TO MVFR CIGS OVERNIGHT AT KCMX AND KSAW...WHICH WILL CONTINUE INTO WED AFTERNOON. HOWEVER...A PERIOD OF HIGH-END MVFR CIGS CANNOT BE RULED OUT AT KSAW LATE TONIGHT INTO WED MORNING. A MIX OF SNOW AND RAIN IS ALSO EXPECTED AT KSAW LATE TONIGHT INTO WED MORNING BUT IS NOT EXPECTED TO BE HEAVY ENOUGH TO RESTRICT VSBY. KIWD WILL BE FARTHER AWAY FROM THE BETTER LOW-LEVEL MOISTURE...BUT A PERIOD OF MVFR CIGS WILL BE POSSIBLE LATE TONIGHT INTO WED MORNING. EXPECT GUSTY NORTH WINDS AT OR ABOVE 20 KNOTS TO DEVELOP TONIGHT AND CONTINUE THROUGH WED AFTERNOON AT BOTH KCMX AND KSAW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 418 PM EDT TUE MAY 3 2016 WINDS WILL BECOME N TO NW AT AROUND 20 KNOTS LATE THIS AFTERNOON AND EVENING BEHIND THE TROUGH/FRONT AND INCREASE TO AS HIGH AS 30 KNOTS OVER THE EAST HALF OF LAKE SUPERIOR LATE TONIGHT INTO WEDNESDAY. A HIGH PRESSURE RIDGE BUILDING OVER THE UPPER GREAT LAKES WILL DIMINISH WINDS TO LESS THAN 20KT LATE WED NIGHT INTO FRIDAY. ANOTHER TROUGH/COLD FRONT MOVING ACROSS THE REGION WILL RESULT IN NW WINDS TO 20 KT OVER THE EAST HALF OF LAKE SUPERIOR LATE FRI NIGHT AND SATURDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...KLUBER MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
322 PM CDT WED MAY 4 2016 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 320 PM CDT WED MAY 4 2016 TWO CONCERNS IN THE SHORT TERM. THE FIRST IS THE THREAT OF FROST TONIGHT WHILE THE SECOND IS WHETHER OR NOT THERE WILL BE WIDELY SCATTERED SHOWERS ACROSS WEST CENTRAL WI ON THURSDAY. BREEZY NORTH TO NORTHWEST WINDS CONTINUED ACROSS THE FA AT MID AFTERNOON WITH THE REGION SANDWICHED BETWEEN HIGH PRESSURE OVER THE EASTERN DAKOTAS AND LOW PRESSURE OVER THE LOWER GREAT LAKES. AFTERNOON HUMIDITY WAS QUITE LOW AND IN THE 20 TO 30 PERCENT RANGE. THE SYSTEM OF HIGH PRESSURE WILL MOVE ACROSS THE FA TONIGHT. WINDS WILL DIMINISH QUICKLY EARLY TONIGHT WITH TEMPERATURES FALLING PRECIPITOUSLY DUE TO THE LOW DEW POINTS. THE LOWEST TEMPERATURES ARE EXPECTED TO BE NORTH AND EAST OF THE TWIN CITIES WITH LOWER TO MIDDLE 30S COMMON. THE LOWER 30S ARE MAINLY CONFINED FROM RUSK THROUGH EAU CLAIRE COUNTIES WHERE A FROST ADVISORY REMAINS IN EFFECT LATE TONIGHT. THERE IS A CONCERN WITH THE LOW TEMPERATURE FORECAST IN THE FACT THAT IT MAY BE TOO COLD OVER NORTHERN AND EASTERN AREAS DUE TO INCREASING MID LEVEL CLOUDINESS LATE IN THE NIGHT. HOWEVER...THE DAMAGE FROM THE FROST MAY BE OVER BY THE TIME THE CLOUDS THICKEN SO THE FROST ADVISORY WAS LEFT IN PLACE. THE INCREASE IN MID LEVEL CLOUDINESS LEADS INTO THE SECOND CONCERN OF WHETHER OR NOT THERE WILL BE SOME SHOWERS ACROSS WEST CENTRAL WI ON THURSDAY. THE CLOUDINESS IS IN RESPONSE TO A SHORTWAVE AND WAA MOVING ACROSS THE AREA. SATURATION AND ADIABATIC OMEGA WAS MOST NOTABLE OVER OUR FAR EASTERN FA THURSDAY MORNING ON THE NAM 300K THETA SURFACE. THIS MOVES OUT OF OUR AREA BY EARLY AFTERNOON. VARIOUS CAMS INCLUDING THE HOPRWRF-TS...NAMNEST...NSSL AND HRRR SHOW AN AREA OF SHOWERS MOVING SOUTHWARD ACROSS THE ARROWHEAD OF MN AFTER 06Z AND PUSHING ACROSS WEST CENTRAL WI IN THE 12Z-18Z PERIOD. IN ADDITION...THE ECMWF HAS BEEN SHOWING THIS AREA OF SHOWERS IN THE AFOREMENTIONED LOCATIONS FOR SEVERAL RUNS NOW. SURROUNDING OFFICES WERE NOT SOLD ON THE MODEL SOLUTIONS AND WENT WITH A SPRINKLE FORECAST. WE USED A VARIETY OF SHORT TERM SOLUTIONS AND INTRODUCED SOME SMALL CHANCES FOR SHOWERS THURSDAY MORNING FROM LADYSMITH THROUGH EAU CLAIRE. LITTLE CHANGE WITH REGARDS TO HIGH TEMPERATURES TOMORROW WITH READINGS RANGING FROM THE UPPER 60S IN EAU CLAIRE TO THE LOWER 80S IN CANBY AND MORRIS. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 320 PM CDT WED MAY 4 2016 THE LONGER TERM CONCERNS REMAIN THE THUNDER CHANCES FRIDAY NIGHT AND OVERALL DEVELOPMENT OF UPPER AIR PATTERN EARLY/INTO MIDWEEK NEXT WEEK. THE COLD FRONT APPEARS TO BE MOVING JUST A BIT FASTER ACCORDING TO THE LATEST DETERMINISITIC RUNS. THE SREF AND 12Z NAM ARE THE SLOWEST WITH THE SOUTHEAST PROGRESSION BY 00Z SAT. IT SHOULD BE POSITIONED NEAR A KJMR-KSTC-KMOX LINE AT THAT TIME. STILL SEE A GOOD THERMAL RIDGE AHEAD OF THE FRONT AND 85-90F LOOKS LIKE A GOOD BET FOR MOST OF CENTRAL/SRN MN FRIDAY AFTERNOON. INSTABILITY INCREASES AND THERE REMAINS WEAK FORCING/CONVERGENCE ALONG THE FRONT. MODELS CONTINUE TO GENERATE AT LEAST SOME SCATTERED CONVECTION ALONG THE FRONT AS IT DROP SOUTHEAST FRIDAY NIGHT. WE WILL HOLD ONTO THE SMALL CHANCE POPS PRIMARILY IN THE 00Z-06Z PERIOD AND TRAIL THEM OFF THROUGH 12Z SAT. COOLER AIR MOVES IN FOR SATURDAY AND SUNDAY WITH DRY HIGH PRESSURE DOMINATING THE WEATHER. THIS SHOULD PROVIDE PLEASANT WEATHER FOR THE WISCONSIN FISHING OPENER ALONG WITH MOTHERS DAY ON SUNDAY. THE LONG TERM MODELS DIVERGE LATER IN THE PERIOD WITH THE OVERALL DEVELOPMENT OF THE WESTERN CONUS CUTOFF CIRCULATION. THE GFS CARRIES MUCH OF THE SYSTEM THE SYSTEM TO THE SOUTH OF THE STATE...WITH PERHAPS THE SOUTHERN THIRD AFFECTED MONDAY/TUESDAY. THE ECMWF CONTINUES ITS TREND OF LIFTING A SERIES OF UPPER LOWS OVER THE AREAS THROUGH MUCH OF NEXT WEEK. THIS WOULD PROVIDE THE GENERALLY CLOUDIER/COOLER AND WETTER CONDITIONS FOR THE REGION. WILL HOLD ONTO THE BLENDED MODEL POP GUIDANCE FOR NOW AND SEE IF THE MODELS COME INTO BETTER AGREEMENT IN FUTURE RUNS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1234 PM CDT WED MAY 4 2016 TWO CONCERNS THIS CYCLE. THE FIRST IS GUSTY NORTHWEST WINDS THROUGH LATE AFTERNOON DUE TO THE GRADIENT BETWEEN HIGH PRESSURE OVER THE EASTERN DAKOTAS AND LOW PRESSURE OVER THE LOWER GREAT LAKES. NW WINDS AROUND 15 KNOTS WITH GUSTS OF 20-25 KNOTS WILL BE COMMON FROM THE TWIN CITIES ON EAST AND SOUTH THROUGH 22Z ALONG WITH A FEW-SCT050-060. THE WINDS WILL BECOME LIGHT AND VARIABLE THIS EVENING THEN BECOME LIGHT SSW ON THURSDAY. THE SECOND CONCERN IS THE THREAT FOR SOME SHOWERS THURSDAY MORNING IN THE 12Z-18Z TIME FRAME. THE GREATEST THREAT AT THIS TIME IS AT KEAU WHERE A PROB30 GROUPS WAS USED. INDICATED VCSH AT KRNH AND KMSP. KMSP...VFR THROUGH THE PERIOD. EXPECT THE GUSTY WINDS TO DIMINISH TO 10 KNOTS OR LESS IN THE 23Z-24Z PERIOD. SMALL THREAT FOR SHOWERS THURSDAY MORNING...ESPECIALLY IN THE 12Z-16Z PERIOD. /OUTLOOK FOR KMSP/ FRI...VFR. SLGT CHC TSRA FRI EVENING. WIND SW 5-10 KTS. SAT...VFR. WIND NE 10-15 KTS. SUN...VFR. WIND N 5 KTS...BECOMING E. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...FROST ADVISORY FROM 3 AM TO 7 AM CDT THURSDAY FOR WIZ016-027-028. MN...NONE. && $$ SHORT TERM...RAH LONG TERM...DWE AVIATION...RAH
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
846 PM MDT THU MAY 5 2016 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY... SENT AN UPDATE TONIGHT TO TRY AND PIECE TOGETHER THE CHANCES FOR PRECIPITATION TONIGHT WITH HOURLY POPS AND WEATHER GRIDS. FOLLOWED THE WETTER GFS AND HRRR SOLUTIONS BUT MUTED THEM SOMEWHAT. THINKING THAT THUNDERSTORM CHANCES WILL DIE OFF AFTER MIDNIGHT. NORTHWEST WINDS HAVE ALREADY BEGUN TO SET UP IN RESPONSE TO THE APPROACHING COLD FRONT WHICH WILL PROBABLY BE THE FOCUS FOR SOME SCATTERED RAIN SHOWERS OVERNIGHT AND TOMORROW MORNING. BMICKELSON PREVIOUS SHORT TERM DISCUSSION...AS THE UPPER RIDGE DRIFTS EASTWARD...SATELLITE IMAGERY IS SHOWING CLOUDINESS BEGINNING TO ENTER THE AREA AS THE NORTHERN STREAM OF THE UPPER LOW TO THE SOUTHWEST IS BEGINNING TO ENTER THE AREA. MODELS ARE FINALLY IN FAIRLY CLOSE AGREEMENT REGARDING THE PLACEMENT AND TIMING OF THE PRECIPITATION...BUT ARE A LITTLE LESS SO ON PRECIPITATION AMOUNTS. WENT WITH A GENERAL CONSENSUS WITH MOST AREAS RECEIVING A FEW HUNDREDTHS TO A COUPLE TENTHS OF AN INCH OF RAIN THROUGH FRIDAY. WITH THE APPROACHING MOISTURE THIS EVENING...THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS OVER OUR WESTERN ZONES TONIGHT AND INTO EARLY FRIDAY MORNING. AFTER SUNRISE FRIDAY THE THUNDERSTORM CHANCES DECREASE AND MAINLY LIGHT SHOWERS ARE EXPECTED. BY FRIDAY AFTERNOON...MODEL AGREEMENT KEEPS MOST OF THE PRECIPITATION SOUTH OF OUR AREA AS A NARROW RIDGE OF HIGH PRESSURE MOVES THROUGH...ALTHOUGH SOME LIGHT SHOWERS COULD LINGER IN OUR SOUTHERN ZONES INTO SATURDAY MORNING. THAT NARROW RIDGE KEEPS US RELATIVELY DRY ON SUNDAY. .LONG TERM...SATURDAY NIGHT THROUGH THURSDAY... BLENDED CURRENT FORECAST WITH THE 12Z MODELS. MODELS CONTINUED TO HAVE TROUBLE WITH RESOLVING SYSTEM EARLY NEXT WEEK WITH THE ECMWF SHOWING MORE OF AN OPEN WAVE AND THUS FASTER. THE GFS CLOSES IT OFF AND GIVES THE CWA MORE PRECIP THROUGH THE REMAINDER OF THE PERIOD. TFJ PREVIOUS DISCUSSION... AN UPPER RIDGE WILL BE OVER THE AREA SATURDAY NIGHT WITH DRY WEATHER. THAT RIDGE WILL MOVE TO THE EAST ON SUNDAY AND AN UPPER TROUGH WILL MOVE IN FROM THE WEST. SUNDAY WILL REMAIN DRY AS IT LOOKS LIKE MOISTURE WILL MOVE INTO THE AREA SUNDAY NIGHT AND MONDAY. A COLD FRONT ASSOCIATED WITH THE SYSTEM WILL MOVE THROUGH EASTERN MONTANA ON MONDAY. ATMOSPHERE MAY BE UNSTABLE ENOUGH FOR THUNDERSTORMS MONDAY AFTERNOON AND EVENING. WILL MENTION A SLIGHT CHANCE FOR NOW. THE UPPER TROUGH AND MOISTURE WILL REMAIN OVER THE AREA ON TUESDAY. WILL MAINTAIN A CHANCE OF SHOWERS. ATMOSPHERE MAY BE UNSTABLE ENOUGH FOR THUNDERSTORMS. WILL MENTION A SLIGHT CHANCE. MODELS DIFFERENCES START APPEARING TUESDAY NIGHT AND WEDNESDAY AS GFS WANTS TO MOVE UPPER TROUGH/LOW TO THE EAST AND ECMWF KEEPS AN UPPER LOW OVER MONTANA. WILL MAINTAIN CHANCE OF SHOWERS. NEXT THURSDAY...GFS HAS NW FLOW ALOFT WITH SHORTWAVES WHILE THE ECMWF MOVES THE UPPER LOW TO THE DAKOTAS. WILL CONTINUE A SLIGHT CHANCE OF SHOWERS. FORRESTER && .AVIATION... SYNOPSIS: A SHORTWAVE TROUGH AND COLD FRONT IS EXPECTED TONIGHT. FLIGHT CATEGORY: VFR. WX/WIND: ISOL TO SCT SHOWERS AND THUNDERSTORMS AND MID LEVEL CLOUDS ARE EXPECTED TONIGHT WITH THE COLD FRONT. EXPECT LIGHT MAINLY SOUTH TO SW WINDS TO BECOME NW TO NORTH 10 TO 20 KNOTS AFTER 06Z TONIGHT AS THE COLD FRONT MOVES THROUGH. WINDS CONTINUE TO TURN CLOCKWISE INTO FRIDAY. TFJ/PROTON && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BUFFALO NY
737 PM EDT THU MAY 5 2016 .SYNOPSIS... AN UPPER LEVEL LOW WILL SLOWLY SPIRAL FROM THE CAROLINAS TONIGHT TO NEW ENGLAND SATURDAY...WITH PERIODIC CHANCES FOR SHOWERS INTO THE WEEKEND. ANOTHER UPPER LEVEL LOW WILL APPROACH FROM THE UPPER GREAT LAKES AND BRING ADDITIONAL RAIN SHOWERS TO THE EASTERN GREAT LAKES REGION SATURDAY NIGHT. TEMPERATURES WILL RISE TO ABOVE NORMAL BY SATURDAY...BEFORE A COLD FRONT CROSSES THE REGION SATURDAY NIGHT RETURNING TEMPERATURES TO BELOW NORMAL AGAIN. && .NEAR TERM /THROUGH FRIDAY/... AN UPPER LEVEL LOW WILL REMAIN STALLED ACROSS THE MID-ATLANTIC STATES WITH OUR REGION REMAINING IN A LIGHT AND LARGELY DRY FLOW. SHOWERS HAVE LARGELY TAPERED OFF...WITH DRY CONDITIONS EXPECTED TO LAST THROUGH THE NIGHT. CLOUD COVER WILL BE PATCHY...BUT MOST PERSISTENT ACROSS SOUTHERN AND EASTERN PORTIONS OF THE CWA. EXPECT LOW TEMPERATURES TO BE SEASONABLE...IN THE LOWER TO MID 40S. TOMORROW AS THIS UPPER LEVEL LOW ADVANCES NORTHWARD ALONG THE ATLANTIC COASTLINE IT WILL SEND ANOTHER SURGE OF MOISTURE BACK OVER OUR REGION...THIS FROM THE SOUTHEAST. IT SHOULD BE A PRETTY NICE DAY ACROSS THE NIAGARA FRONTIER AND SAINT LAWRENCE VALLEY WITH MORNING SUNSHINE GIVING WAY TO HIGH CLOUDS IN THE AFTERNOON. SHOWERS WILL SPREAD INTO THE REGION FROM THE SE WITH THIS UPPER LOW...LIKELY REACHING THE SOUTHERN GENESEE VALLEY AND FINGER LAKES REGION IN THE AFTERNOON. WILL HAVE HIGH CHANCE TO LOW LIKELY POPS HERE...TAPERING DOWN TO SLIGHT CHANCE ALONG THE NW AREAS OF WNY AND THE SLV. WITH 850 HPA TEMPERATURES A FEW DEGREES WARMER THAN TODAY...A 4 TO 6C 850 HPA TEMPERATURE SHOULD RESULT IN HIGHS IN THE LOW TO MID 60S...WITH JUST A FEW LOCATIONS REMAINING IN THE UPPER 50S OVER THE INLAND SOUTHERN TIER. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... SHOWERS SHOULD CONTINUE THROUGH FRIDAY EVENING FOR AT LEAST SOUTHERN AND EASTERN PORTIONS OF THE AREA AS ANOTHER DISTURBANCE ROTATES AROUND THE PERIPHERY OF THE CUT-OFF LOW...WHICH IS FORECAST TO STALL OVER NORTHERN VIRGINIA/MARYLAND. AS THE THE LOW GRADUALLY FILLS OVERNIGHT...CHANCES FOR SHOWERS WILL DIMINISH. THE CUT-OFF LOW WEAKENS IN PLACE OVER THE MID ATLANTIC REGION SATURDAY...HOWEVER WE WILL REMAIN UNDER THE INFLUENCE OF LINGERING CYCLONIC FLOW. SO WHILE SOME BREAKS OF SUNSHINE LOOK POSSIBLE EXPECT MUCH OF THE DAY COULD END UP MOSTLY CLOUDY. WITH THE CYCLONIC FLOW STILL IN PLACE AND SOME RESIDUAL LOW LEVEL MOISTURE...ISOLATED TO WIDELY SCATTERED SHOWERS CANNOT BE RULED OUT. TEMPERATURES SHOULD REACH IN THE UPPER 60S TO LOWER 70S DEPENDING ON HOW MUCH SUNSHINE IS REALIZED. LAKESHORE AREAS WILL BE SEVERAL DEGREES COOLER AS LAKE BREEZE CIRCULATIONS SET UP. THE UPPER LOW THAT HAS BEEN PLAGUING THE REGION IS EXPECTED TO OPEN BY SATURDAY NIGHT. LASTEST GUIDANCE IS IN AGREEMENT IT WILL CONSOLIDATED WITH A LARGE UPPER LOW THAT DEVELOPS NEAR HUDSON BAY AS A VIGOROUS SHORT WAVE MOVES ACROSS THE GREAT LAKES REGION SATURDAY NIGHT. AS THE SHORT WAVE ROTATES ABOUT THE UPPER LOW IT WILL MOVE ACROSS THE NORTHEAST DRIVING A STRONG COLD FRONT ACROSS THE REGION. A ROUND OF SHOWERS AND PERHAPS A FEW THUNDERSTORMS ARE EXPECTED SATURDAY NIGHT INTO SUNDAY AS THIS SHORT WAVE AND COLD FRONT CROSS THE REGION. IN WAKE OF THE FRONT...GUSTY WEST TO NORTHWEST WINDS WILL DEVELOPED DURING THE DAY SUNDAY. IT WILL BE NOTABLY COOLER WITH TEMPERATURES A SOLID 10 TO 15 DEGREES COOLER THAN SATURDAY WITH MOST HIGHS REMAINING IN THE 50S. FOR THE MOST PART...THE DAY WILL BE DRY OUTSIDE OF LINGERING MORNING SHOWERS ACROSS THE NORTH COUNTRY AND SOME ISOLATED DIRUNALLY DRIVEN SHOWERS. && .LONG TERM /MONDAY THROUGH THURSDAY/... ON MONDAY THE MID LEVEL TROUGH OVER QUEBEC WILL PULL AWAY FROM THE AREA WITH SURFACE HIGH PRESSURE BUILDING INTO THE GREAT LAKES REGION. THIS WILL BRING A RETURN TO DRY WEATHER AND SUNSHINE TO START THE WEEK. TEMPERATURES ALOFT WILL BEGIN TO RECOVER AS THE MID LEVEL LOW PULLS AWAY...WITH HIGHS IN THE LOWER 60S ACROSS LOWER ELEVATIONS AWAY FROM THE LAKESHORES. MODEL GUIDANCE BEGINS TO DIVERGE BY MONDAY NIGHT AND TUESDAY WITH THE HANDLING OF THE NEXT SYSTEM APPROACHING THE REGION. A MID LEVEL CLOSED LOW WILL PROGRESS EASTWARD THROUGH THE CENTRAL PLAINS THIS PERIOD...WITH A BROAD REGION OF WARM ADVECTION AND DEEPER MOISTURE SPREADING NORTHEAST THROUGH THE OHIO VALLEY. THE ECMWF AND CANADIAN GEM ARE FASTER AND FARTHER EAST WITH THIS SYSTEM...BRINGING WARM FRONTAL SHOWERS INTO OUR REGION BY LATER MONDAY NIGHT AND TUESDAY. THE GFS IS SLOWER AND FARTHER WEST WITH THIS SYSTEM...KEEPING OUR REGION DRY THROUGH TUESDAY. THE LATEST 12Z GEFS SHOW A VARIETY OF SOLUTIONS WITH SOME MEMBERS FASTER AND SIMILAR TO THE ECMWF/GEM SOLUTION. WITH THIS IN MIND...HAVE INCREASED POPS TO MID RANGE CHANCE FROM LATER MONDAY NIGHT INTO TUESDAY. WEDNESDAY INTO THURSDAY THE FRONTAL ZONE IS FORECAST TO STALL FROM THE OHIO VALLEY INTO THE NORTHERN MID ATLANTIC...WITH ONE OR TWO WAVES OF LOW PRESSURE RUNNING ALONG THE BOUNDARY. THIS WILL KEEP UNSETTLED WEATHER ACROSS OUR REGION WITH A CHANCE OF SOME RAIN BOTH DAYS...WITH THE GREATEST CHANCES FOR STEADIER SHOWERS ACROSS THE SOUTHERN HALF OF THE AREA GIVEN THE PLACEMENT OF THE FRONTAL ZONE. TEMPERATURES WILL REMAIN CLOSE TO SEASONAL NORMS THROUGH THE MIDDLE OF THE WEEK WITH HIGHS IN THE 60S AND LOWS IN THE UPPER 40S. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... AT 23Z...THERE WAS WIDESPREAD VFR CONDITIONS ACROSS THE AREA...WITH THE MOST PERSISTENT (BUT STILL VFR) CLOUD COVER ACROSS SE PORTIONS OF THE AREA. THERE IS MODERATE CONFIDENCE THAT VFR CONDITIONS WILL CONTINUE OVERNIGHT. THE HRRR DOES DEVELOP FOG AND STRATUS...HOWEVER THERE IS LITTLE SUPPORT FROM OTHER GUIDANCE AND SATELLITE IMAGERY SHOWS IT IS ALREADY OVERDONE. ALL TAFS ARE VFR TONIGHT...WITH A SMALL CHANCE OF FOG DEVELOPING IN THE 08Z TO 13Z TIMEFRAME. EXPECT VFR CONDITIONS TO CONTINUE ON FRIDAY...WITH HIGH CLOUDS LOWERING AND THICKENING FROM THE SE LATE IN THE AFTERNOON. ANY SHOWERS SHOULD HOLD OFF UNTIL JUST AFTER 00Z SATURDAY. OUTLOOK... FRIDAY NIGHT...VFR/MVFR WITH SHOWERS LIKELY...MAINLY ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER AND FINGER LAKES. SATURDAY...VFR. SATURDAY NIGHT...SHOWERS WITH A CHANCE OF THUNDERSTORMS. IFR/MVFR SUNDAY...MAINLY VFR WITH A CHANCE OF MORNING SHOWERS EAST OF KROC/KDSV. MONDAY...VFR. MONDAY NIGHT AND TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS. && .MARINE... THROUGH SATURDAY A RELATIVELY WEAK PRESSURE GRADIENT WILL OCCUR ACROSS THE LOWER LAKES REGION. THIS WILL RESULT IN LIGHT TO MODEST WINDS PREDOMINATING...ALONG WITH CORRESPONDINGLY MINIMAL WAVES. A COLD FRONT WILL CROSS THE LOWER LAKES SATURDAY NIGHT...AND WAVES ON LAKE ONTARIO WILL LIKELY NEAR SMALL CRAFT ADVISORY THRESHOLDS LATER SATURDAY NIGHT AND THROUGH SUNDAY. THE WESTERLY FLOW WILL YIELD LOWER WAVE HEIGHTS ON LAKE ERIE...SUCH THAT WAVES MAY REMAIN BELOW SCA THROUGH THE WEEKEND. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...THOMAS NEAR TERM...APFFEL/THOMAS SHORT TERM...TMA LONG TERM...HITCHCOCK AVIATION...APFFEL MARINE...THOMAS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
651 PM EDT WED MAY 4 2016 .SYNOPSIS... A COLD FRONT WILL SINK SLOWLY SOUTH THROUGH THE AREA TONIGHT. A POTENT UPPER LEVEL LOW WILL DROP SOUTH WITH A SERIES OF SURFACE LOWS CROSSING THE AREA THROUGH EARLY SATURDAY. A WEAK COLD FRONT WILL APPROACH FROM THE NORTH SUNDAY INTO MONDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... AS OF 645 PM WED...EARLIER CONVECTION THAT FIRED ON SEA BRZ IS DIMINISHING. WILL KEEP SLIGHT POP IN CORRIDOR JUST INLAND FROM CST CPL MORE HOURS THEN MAINLY DRY OVERNIGHT...WITH POSS SOME SHRA MOVING INTO NW TIER VERY LATE. AS NNE WINDS DEVELOP IN WAKE OF FRONT EXPECT SOME LOW CLOUDS AND PERHAPS SOME FOG TO SPREAD SW OVER THE REGION LATER TONIGHT. OVERNIGHT LOWS WILL BE IN THE MID TO UPPER 50S INLAND AND THE UPPER 50S TO AROUND 60 OUTER BANKS. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... AS OF 330 PM WED...THE UPPER LOW WILL MOVE SOUTHEAST OVER THE AREA THURSDAY. VERY COLD TEMPERATURES ALOFT /PERHAPS MONTHLY-DAILY RECORDS FOR TEMPS ALOFT/ AND SURFACE HEATING WILL LEAD TO STEEP MID LEVEL LAPSE RATES AND MODEST INSTABILITY. THIS IN COMBINATION WITH DEEP CYCLONIC FLOW WILL LEAD TO THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. WAS TEMPTED TO GO WITH LIKELY POPS FOR THE ENTIRE AREA BUT FOR NOW WILL KEEP LIKELY OVER THE NW THIRD OF THE REGION WITH HIGH CHANCE POPS ELSEWHERE. SMALL HAIL WILL BE POSSIBLE IN THE STRONGEST CELLS DUE TO THE COLD TEMPS ALOFT. HIGHS THURSDAY WILL BE BELOW NORMAL WITH READINGS ONLY IN THE MID 60S OUTER BANKS AND UPPER 6OS TO LOWER 70S INLAND. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... AS OF 3 PM WEDNESDAY...AN OMEGA BLOCK TYPE PATTERN WILL CONTINUE THROUGH SATURDAY AS AN UPPER CLOSED LOW DROPS SOUTH INTO THE MID- ATLANTIC REGION THROUGH FRIDAY, EVENTUALLY SHIFTING OUT TO SEA BY LATE SATURDAY. THURSDAY NIGHT THROUGH SATURDAY: A SERIES OF SHORTWAVES WILL RIDE THE APPROACHING UPPER CLOSED LOW SUPPLYING A ROUND OR TWO OF PRECIPITATION ACROSS THE AREA. THE FIRST SFC LOW WILL DROP SOUTH THROUGH THE REGION THURSDAY NIGHT INTO EARLY FRIDAY. THIS WILL YIELD CHC SHOWERS ACROSS THE REGION, ESPECIALLY TO THE NORTH WHERE THE BEST LIFT IS REALIZED. ANOTHER WEAKER SHORTWAVE WILL CROSS THE NORTHERN TIER EARLY SATURDAY WITH A SCHC SHOWERS DURING THIS TIME. THE ATMOSPHERE WILL BE DRYING RAPIDLY, SO FEEL THE SHOWER ACTIVITY SHOULD DWINDLE RAPIDLY THROUGH THE DAY SATURDAY FROM WEST TO EAST. GIVEN WEST WINDS, CLOUD COVER AND SOME SHOWER ACTIVITY, TEMPERATURE WILL STRUGGLE TO REACH 70 ON FRIDAY. THE FLOW BECOMES MORE NWLY ALLOWING SUBSIDENCE SATURDAY. THIS IN ADDITION TO LESS CLOUD COVER/SHOWER ACTIVITY WOULD SUGGEST TEMPERATURES SHOULD REBOUND TO THE LOW 70S INLAND AND UPPER 60S ALONG THE OBX. SUNDAY THROUGH WEDNESDAY: RETURN FLOW WILL DEVELOP BRIEFLY JUST AHEAD OF A FRONT THAT IS PROGGED TO CROSS LATE SUNDAY. THE FRONT WILL BECOME STALLED ACROSS THE AREA SUNDAY NIGHT INTO MONDAY WITH LITTLE IN THE WAY OF MOISTURE ASSOCIATED WITH IT. THE FRONT EVENTUALLY WASHES OUT MONDAY WITH RETURN FLOW DEVELOPING TUESDAY INTO WEDNESDAY AHEAD OF THE NEXT SYSTEM. FEEL THE CHANCES OF SHOWERS/THUNDERSTORMS WILL INCREASE WEDNESDAY AS BETTER LIFT AND MOISTURE MOVES INTO THE REGION AHEAD OF THE FRONT. TEMPERATURES WILL SLOWLY INCREASE THROUGH THIS TIME PERIOD, PERHAPS DROPPING A DEGREE OR TWO MONDAY GIVEN THE FRONT BISECTING EASTERN NC. HIGH TEMPERATURES WILL BE IN THE LOW 80S INLAND TO MID 70S ALONG THE COAST FOR BOTH SUNDAY AND MONDAY. TEMPS REALLY RAMP UP BY MID WEEK AS WARM RETURN FLOW INCREASES. HIGHS IN THE MID 80S INLAND TO MID 70S ALONG THE OBX. LOW TEMPS INCREASING THROUGH THE WEEK AS WELL, LOW TO MID 60S. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... SHORT TERM /THROUGH THURSDAY AFTERNOON/... AS OF 645 PM WED...VFR THRU THE EVENING WITH SCT CLOUD...ISOLD CONVECTION SHLD STAY E OF TAF SITES EARLY EVENING. AFTER 06Z WENT CLOSE TO HRRR MODEL WITH IFR STRATUS SPREADING SW OVER ERN NC...COULD ALSO BE SOME FOG AS LOW LVLS WILL BE SATURATED. THIS STRATUS AND FOG WILL CONT THRU ABOUT 12Z THEN SLOWLY LIFT TO MVFR AND EVENTUALLY MAINLY VFR THU. VERY COLD TEMPS ALOFT WILL LEAD TO NUMEROUS SHRA AND A FEW TSRA DEVELOPING OVER REGION LATER WHICH COULD LEAD TO OCNL SUB VFR. LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 3 PM WEDNESDAY...WITH A SERIES OF SFC LOWS CROSSING THE AREA THROUGH SATURDAY, EXPECT SHOWER ACTIVITY TO BE OFF AND ON AT THE TAF SITES WITH VARIABLE WINDS. THE BEST CHANCE FOR RAIN WILL BE THURSDAY NIGHT INTO EARLY FRIDAY. POSSIBLY SCHC SHOWERS EARLY SATURDAY AS AN UPPER LEVEL LOW MOVES OUT TO SEA. GIVEN THE LOW LEVEL MOISTURE IN PLACE, FRIDAY AND ESPECIALLY SATURDAY MORNING WE COULD SEE STRATUS/FOG DEVELOP. CONDITIONS IMPROVE THROUGH MONDAY AS DRIER AIR WORKS ITS WAY INTO THE AREA. RETURN FLOW INCREASES SUNDAY AHEAD OF A BACKDOOR FRONT WHICH WILL STALL ACROSS EASTERN NC AND BECOME WASHED OUT. DO NOT EXPECT PRECIPITATION WITH THIS FROPA. && .MARINE... SHORT TERM /THROUGH THURSDAY/... AS OF 645 PM WED...NO CHANGES WITH FRONT OVER NRN TIER EXPECTED TO PUSH S OVERNIGHT. PREV DISC...WINDS ARE EXPECTED TO BE 10 TO 15 KT THROUGH THURSDAY. A COLD FRONT WAS BECOMING STATIONARY FROM JUST SOUTH OF OREGON INLET SOUTHWEST TO JUST WEST OF THE CRYSTAL COAST. AHEAD OF THE FRONT SW FLOW IS 10 TO 15 KT WHILE BEHIND THE BOUNDARY WINDS ARE NORTH AROUND 10 KT. SEAS ARE RUNNING 2 TO 4 FT. EXPECT THE NORTHERLY FLOW TO SPREAD WITH THE FRONTAL PASSAGE LATE TONIGHT BECOME NE 10 TO 15 KT NORTH OF CAPE LOOKOUT FROM TONIGHT THROUGH THURSDAY. SOUTH OF CAPE LOOKOUT THE GRADIENT WILL BE WEAKER BEHIND THE FRONT AND EXPECT NORTH TO NORTHEAST FLOW 10 KT OR LESS LATE TONIGHT INTO THURSDAY. SEAS SHOULD CONTINUE 2 TO 4 FT THROUGH THE PERIOD. LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 3 PM WEDNESDAY...A SERIES OF SURFACE LOWS/FRONTS WILL CROSS THE COASTAL WATERS AS A POTENT UPPER LEVEL LOW PIVOTS THROUGH THE REGION THURSDAY NIGHT THROUGH SATURDAY. THIS WILL MEAN VARIABLE WINDS AROUND 10-15KTS AND SEAS AROUND 3 TO 5 FEET THROUGH MUCH OF THE FIRST HALF OF THE PERIOD. HIGH PRESSURE WILL BUILD IN BRIEFLY, JUST AHEAD OF A FRONT THAT WILL CROSS SUNDAY/SUNDAY NIGHT, BECOMING WASHED OUT ACROSS THE SOUTHERN WATERS MONDAY. GIVEN THIS PATTERN, EXPECT LIGHT AND VARIABLE WINDS AND SEAS 2 TO 3 FEET LATE SUNDAY THROUGH MONDAY. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JME NEAR TERM...RF/JME SHORT TERM...JME LONG TERM...LEP AVIATION...RF/LEP MARINE...RF/JME/LEP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
943 PM CDT THU MAY 5 2016 .UPDATE... ISSUED AT 943 PM CDT THU MAY 5 2016 MOST OF THE CUMULUS AND ISOLATED...HIGH-BASED SHOWERS /AND A LONE STORM THAT OCCURRED IN WILLIAMS COUNTY EARLIER/ ARE DIMINISHING WITH THE ONSET OF NOCTURNAL COOLING AND STABILIZATION. THAT IS IN LINE WITH OUR LATE AFTERNOON FORECAST UPDATE. THE MAIN QUESTION GOING FORWARD WILL BE WHAT /IF ANY/ SHOWER POTENTIAL EXISTS OVER- NIGHT. RECENT OPERATIONAL HRRR SIMULATIONS CONTINUE TO BE TOO AGGRESSIVE WITH CONVECTIVE DEVELOPMENT COMPARED TO REALITY...AND THE 18 UTC GFS AND 00 UTC NAM ARE AT ODDS OVER SHOWER POTENTIAL. THAT PROVIDED LOW ENOUGH CONFIDENCE FOR US TO KEEP A DRY FORECAST GOING OVERNIGHT...THOUGH THAT WILL NEED TO BE RE-EVALUATED LATER. THE ONE CHANGE WE DID MAKE WITH THIS UPDATE WAS TO INCREASE LOWS BY 2-4 F IN MOST AREAS BASED ON MID-EVENING TEMPERATURE TRENDS. FINALLY...ONE OTHER ISSUE THAT WE WILL NEED TO CONTEND WITH FOR LATER FORECAST RELEASES IS HOW THICK SMOKE FROM CANADIAN FIRES MAY BE FRIDAY. OBSERVATIONS IN SASKATCHEWAN HAVE SHOWN VISIBILITIES AS LOW AS 4SM FOR SEVERAL HOURS BEHIND THE COLD FRONT THAT WILL CROSS THE AREA. THUS...IT/S POSSIBLE THICKER LOW-LEVEL SMOKE MAY IMPACT PARTS OF WESTERN AND CENTRAL ND LATE TONIGHT AND FRIDAY. AT THE VERY LEAST IT SEEMS REASONABLE TO BELIEVE THE SMOKE WILL BE SENSIBLE VIA SMELL FRIDAY. UPDATE ISSUED AT 755 PM CDT THU MAY 5 2016 WE WILL LET THE RED FLAG WARNING EXPIRE AS SCHEDULED AT 8 PM CDT /01 UTC/...AS WINDS IN EAST CENTRAL ND HAVE DIMINISHED TO AROUND 10 MPH. HUMIDITIES ARE AT OR ABOVE 20 PERCENT AS OF 0050 UTC AND THEY WILL CONTINUE A SLOW RISE WITH THE ONSET OF DIURNAL COOLING. UPDATE ISSUED AT 551 PM CDT THU MAY 5 2016 WE HAVE ADDED A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM TO THE FORECAST THROUGH MID EVENING IN NORTHWEST ND. A HIGH-BASED SHOWER DEVELOPED NORTHWEST OF WILLISTON NEAR 2230 UTC...AND EVEN THOUGH THE ENTLN TOTAL LIGHTNING PLOT HAS NOT YET SHOWN ANY IN-CLOUD OR CLOUD-TO-GROUND STRIKES...THE STEEP LAPSE RATES AND WEAK MLCAPE /UP TO 250 J/KG PER THE SPC MESOANALYSIS/ IN THAT AREA SUGGEST A RUMBLE OR TWO OF THUNDER IS POSSIBLE. VISIBLE SATELLITE IMAGERY THROUGH 2245 UTC SHOWS CUMULUS ALL ALONG A WEAK SURFACE PRESSURE TROUGH EXTENDING FROM SOUTHEAST SASKATCHEWAN INTO EASTERN MT SO IT IS PLAUSIBLE MORE THAN JUST THAT INITIAL SHOWER MAY FORM. THAT BEING SAID...RECENT HRRR RUNS ARE LIKELY OVERDONE WITH EXPECTED DEVELOPMENT BASED ON THAT MODEL/S RECENT AND LONGER-TERM BIASES. OTHERWISE...WE ARE CONTINUING THE RED FLAG WARNING IN EAST CENTRAL ND FOR NOW GIVEN LATE-AFTERNOON OBSERVATIONS AND ONGOING FIRES. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 235 PM CDT THU MAY 5 2016 THE MAIN IMPACTS IN THE SHORT TERM ARE CRITICAL FIRE CONDITIONS TODAY AND A COLD FRONT TOMORROW. AN UPPER LEVEL RIDGE...COMBINED WITH A SURFACE TROUGH AND SOUTHWESTERLY MIXING WINDS...HAVE ALLOWED TEMPERATURES THIS AFTERNOON TO RISE RAPIDLY INTO THE 80S AND LOW 90S. THESE WARM TEMPERATURES HAVE FURTHER EXACERBATED DRY BOUNDARY LAYER CONDITIONS. WITH VERY DRY AIR MIXING DOWN RELATIVE HUMIDITY VALUES HAVE PLUMMETED INTO THE TEENS AND LOW 20S. WIND SPEEDS HAVE BEEN A BIT BREEZY ACROSS THE JAMES VALLEY. THIS IS WHAT PROMPTED THE ISSUANCE OF THE RED FLAG WARNING. WIND SPEEDS AROUND 20 MPH...COMBINED WITH HUMIDITY 20 PERCENT OR LESS AND DRY FUELS IS PRODUCING CRITICAL FIRE CONDITIONS ACROSS THE JAMES VALLEY. A COLD FRONT WILL SWEEP THROUGH TONIGHT INTO FRIDAY MORNING. WINDS WILL SHIFT OUT OF THE NORTH BETWEEN 20 AND 30 MPH. TOMORROW AFTERNOON MINIMUM RELATIVE HUMIDITY AROUND 20 PERCENT IS EXPECTED IN NORTHWEST AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA BY LATE AFTERNOON. HOWEVER...BY THIS TIME THE STRONGEST WINDS SHOULD HAVE PASSED TO THE SOUTH. THEREFORE...THESE AREAS MAY ESCAPE CRITICAL FIRE CONDITIONS. MODELS CONTINUE TO INDICATE A MAINLY DRY FRONTAL PASSAGE...WITH A FEW ISOLATED SHOWERS POSSIBLE. HOWEVER...WITH A PERSISTANT DRY BOUNDARY LAYER...THE LIKELIHOOD OF ANY PRECIPITATION ACTUALLY REACHING THE GROUND IS RATHER MINIMAL. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 235 PM CDT THU MAY 5 2016 COOLER AIR WILL SETTLE INTO THE AREA THIS WEEKEND IN THE WAKE OF FRIDAYS COLD FRONT. HOWEVER... PLEASANT TEMPERATURES ARE STILL EXPECTED WITH HIGHS MAINLY IN THE 70S. DRY CONDITIONS WILL REMAIN. CHANGES APPEAR ON THE HORIZON FOR THE START THE WORK WEEK AS AN UPPER LOW CURRENTLY OFF THE CALIFORNIA COAST DEEPENS OVER THE FOUR CORNERS REGION THIS WEEKEND AND LIFTS INTO THE PLAINS ON MONDAY...BRINGING CHANCES FOR RAIN AND THUNDERSTORMS. CHANCES FOR RAIN AND THUNDERSTORMS WILL LINGER OVER THE AREA THROUGH THE WEEK AS THE GFS AND ECMWF HAVE THE LOW REMAINING NEARBY THROUGH FRIDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 943 PM CDT THU MAY 5 2016 VFR CONDITIONS ARE FORECAST TONIGHT AND FRIDAY...BUT THERE IS A LOW PROBABILITY OF SUB-VFR SMOKE AFFECTING PARTS OF THE AREA. THE MAIN AVIATION WEATHER ISSUE WILL BE A COLD FRONTAL PASSAGE LATE TONIGHT AND FRIDAY MORNING...WHICH WILL SHIFT WINDS TO THE NORTH. NORTHERLY WIND GUSTS TO AROUND 30 KT WILL OCCUR FRIDAY ACROSS ALL OF WESTERN AND CENTRAL ND. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CJS SHORT TERM...AJ LONG TERM...AJ AVIATION...CJS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
755 PM CDT THU MAY 5 2016 .UPDATE... ISSUED AT 755 PM CDT THU MAY 5 2016 WE WILL LET THE RED FLAG WARNING EXPIRE AS SCHEDULED AT 8 PM CDT /01 UTC/...AS WINDS IN EAST CENTRAL ND HAVE DIMINISHED TO AROUND 10 MPH. HUMIDITIES ARE AT OR ABOVE 20 PERCENT AS OF 0050 UTC AND THEY WILL CONTINUE A SLOW RISE WITH THE ONSET OF DIURNAL COOLING. UPDATE ISSUED AT 551 PM CDT THU MAY 5 2016 WE HAVE ADDED A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM TO THE FORECAST THROUGH MID EVENING IN NORTHWEST ND. A HIGH-BASED SHOWER DEVELOPED NORTHWEST OF WILLISTON NEAR 2230 UTC...AND EVEN THOUGH THE ENTLN TOTAL LIGHTNING PLOT HAS NOT YET SHOWN ANY IN-CLOUD OR CLOUD-TO-GROUND STRIKES...THE STEEP LAPSE RATES AND WEAK MLCAPE /UP TO 250 J/KG PER THE SPC MESOANALYSIS/ IN THAT AREA SUGGEST A RUMBLE OR TWO OF THUNDER IS POSSIBLE. VISIBLE SATELLITE IMAGERY THROUGH 2245 UTC SHOWS CUMULUS ALL ALONG A WEAK SURFACE PRESSURE TROUGH EXTENDING FROM SOUTHEAST SASKATCHEWAN INTO EASTERN MT SO IT IS PLAUSIBLE MORE THAN JUST THAT INITIAL SHOWER MAY FORM. THAT BEING SAID...RECENT HRRR RUNS ARE LIKELY OVERDONE WITH EXPECTED DEVELOPMENT BASED ON THAT MODEL/S RECENT AND LONGER-TERM BIASES. OTHERWISE...WE ARE CONTINUING THE RED FLAG WARNING IN EAST CENTRAL ND FOR NOW GIVEN LATE-AFTERNOON OBSERVATIONS AND ONGOING FIRES. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 235 PM CDT THU MAY 5 2016 THE MAIN IMPACTS IN THE SHORT TERM ARE CRITICAL FIRE CONDITIONS TODAY AND A COLD FRONT TOMORROW. AN UPPER LEVEL RIDGE...COMBINED WITH A SURFACE TROUGH AND SOUTHWESTERLY MIXING WINDS...HAVE ALLOWED TEMPERATURES THIS AFTERNOON TO RISE RAPIDLY INTO THE 80S AND LOW 90S. THESE WARM TEMPERATURES HAVE FURTHER EXACERBATED DRY BOUNDARY LAYER CONDITIONS. WITH VERY DRY AIR MIXING DOWN RELATIVE HUMIDITY VALUES HAVE PLUMMETED INTO THE TEENS AND LOW 20S. WIND SPEEDS HAVE BEEN A BIT BREEZY ACROSS THE JAMES VALLEY. THIS IS WHAT PROMPTED THE ISSUANCE OF THE RED FLAG WARNING. WIND SPEEDS AROUND 20 MPH...COMBINED WITH HUMIDITY 20 PERCENT OR LESS AND DRY FUELS IS PRODUCING CRITICAL FIRE CONDITIONS ACROSS THE JAMES VALLEY. A COLD FRONT WILL SWEEP THROUGH TONIGHT INTO FRIDAY MORNING. WINDS WILL SHIFT OUT OF THE NORTH BETWEEN 20 AND 30 MPH. TOMORROW AFTERNOON MINIMUM RELATIVE HUMIDITY AROUND 20 PERCENT IS EXPECTED IN NORTHWEST AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA BY LATE AFTERNOON. HOWEVER...BY THIS TIME THE STRONGEST WINDS SHOULD HAVE PASSED TO THE SOUTH. THEREFORE...THESE AREAS MAY ESCAPE CRITICAL FIRE CONDITIONS. MODELS CONTINUE TO INDICATE A MAINLY DRY FRONTAL PASSAGE...WITH A FEW ISOLATED SHOWERS POSSIBLE. HOWEVER...WITH A PERSISTANT DRY BOUNDARY LAYER...THE LIKELIHOOD OF ANY PRECIPITATION ACTUALLY REACHING THE GROUND IS RATHER MINIMAL. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 235 PM CDT THU MAY 5 2016 COOLER AIR WILL SETTLE INTO THE AREA THIS WEEKEND IN THE WAKE OF FRIDAYS COLD FRONT. HOWEVER... PLEASANT TEMPERATURES ARE STILL EXPECTED WITH HIGHS MAINLY IN THE 70S. DRY CONDITIONS WILL REMAIN. CHANGES APPEAR ON THE HORIZON FOR THE START THE WORK WEEK AS AN UPPER LOW CURRENTLY OFF THE CALIFORNIA COAST DEEPENS OVER THE FOUR CORNERS REGION THIS WEEKEND AND LIFTS INTO THE PLAINS ON MONDAY...BRINGING CHANCES FOR RAIN AND THUNDERSTORMS. CHANCES FOR RAIN AND THUNDERSTORMS WILL LINGER OVER THE AREA THROUGH THE WEEK AS THE GFS AND ECMWF HAVE THE LOW REMAINING NEARBY THROUGH FRIDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 551 PM CDT THU MAY 5 2016 VFR CONDITIONS WILL CONTINUE TONIGHT AND FRIDAY. ISOLATED SHOWERS OR THUNDERSTORMS ARE POSSIBLE IN NORTHWEST ND THIS EVENING. THE MAIN AVIATION WEATHER ISSUE WILL BE A COLD FRONTAL PASSAGE LATE TONIGHT AND FRIDAY MORNING...WHICH WILL SHIFT WINDS TO THE NORTH. NORTHERLY WIND GUSTS TO AROUND 30 KT WILL OCCUR FRIDAY ACROSS ALL OF WESTERN AND CENTRAL ND. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CJS SHORT TERM...AJ LONG TERM...AJ AVIATION...CJS
AREA FORECAST DISCUSSION
NWS MEDFORD OR
859 PM PDT THU MAY 5 2016 .SHORT TERM...A UPPER LOW CENTERED ALONG THE CENTRAL CALIFORNIA COAST IS BRINGING WRAP AROUND MOISTURE INTO THE AREA. THE FORECAST REMAINS ON TRACK WITH THIS LOW GRADUALLY SHIFTING INLAND FRIDAY AND BRINGING NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS TO THE AREA. SCATTERED SHOWERS ARE OVER THE AREA THIS EVENING. THUNDERSTORMS HAVE DIMINISHED. HOWEVER...ADDITIONAL SHORTWAVE ACTIVITY IS EXPECTED TO MOVE INTO THE AREA TONIGHT FROM THE SOUTH. THIS WILL BRING ADDITIONAL CHANCES FOR THUNDERSTORMS TONIGHT. THE CURRENT HIGH RESOLUTION HRRR INDICATES THE BEST POTENTIAL FOR THUNDERSTORMS TONIGHT WILL BE IN THE MODOC...LAKE AND EASTERN SISKIYOU COUNTY AREAS. STORM MOTION HAS BEEN RELATIVELY SLOW AROUND 5 MPH THIS EVENING WILL PICK UP SLIGHTLY TONIGHT INTO FRIDAY. SIGNIFICANT MOISTURE IS EXPECTED WITH STORMS INTO FRIDAY. ALSO ON FRIDAY AS ADDITIONAL SHORTWAVE ENERGY MOVE INTO THE AREA AND CAPE AND INSTABILITY INCREASE, EXPECT A SLIGHT CHANCE FOR STORMS TO BECOME SEVERE. THE MAIN CONCERN WITH SEVERE STORMS IS THE POTENTIAL FOR LARGE HAIL AND STRONG WINDS AS WELL AS LOCALIZED FLOODING. && .AVIATION...FOR THE 06/00Z TAF CYCLE...THE MAIN CONCERN THROUGH FRIDAY EVENING WILL BE THUNDERSTORMS. THUNDERSTORMS ARE LIKELY TO BE MORE NUMEROUS AND MORE LIKELY TO BE STRONG ON FRIDAY AFTERNOON AND EVENING. THESE THUNDERSTORMS WILL BE SLOW MOVING AND PRODUCE MODERATE TO HEAVY RAIN AND THEY MAY PRODUCE GUSTY OUTFLOW WINDS, AND HAIL. THE BEST CHANCE THIS EVENING WILL BE OVER THE SOUTHERN OREGON CASCADE FOOTHILLS...CASCADES AND WESTERN AND CENTRAL SISKIYOU COUNTY WITH A SECONDARY FOCUS OVER MODOC AND LAKE COUNTIES. THUNDERSTORMS ON FRIDAY ARE EXPECTED TO BE MOST NUMEROUS EAST OF THE CASCADES ALTHOUGH ISOLATED STORMS MAY DEVELOP IN SOUTHWEST OREGON AND WESTERN SISKIYOU COUNTY. THERE WILL BE A MIX OF MVFR AND VFR CIGS OVERNIGHT WITH MOUNTAIN OBSCURATIONS POSSIBLE IN SHOWERS AND THUNDERSTORMS. CONDITIONS WILL IMPROVE TO WIDESPREAD VFR DURING FRIDAY MORNING BUT SHOWERS AND THUNDERSTORMS DEVELOPING LATE MORNING INTO THE EVENING WILL ONCE AGAIN CREATE AREAS OF MVFR WITH POTENTIALLY HAZARDOUS CONDITIONS. -DW && .MARINE...UPDATED 430 PM PDT THU 5 MAY 2016...OFFSHORE HIGH PRESSURE AND INLAND LOW PRESSURE WILL PRODUCE PERSISTENT GUSTY NORTHERLY WINDS AND STEEP TO VERY STEEP SEAS THROUGH FRIDAY EVENING. THE STRONGEST WINDS AND HIGHEST SEAS WILL OCCUR OVER THE OUTER WATERS SOUTH OF CAPE BLANCO. WINDS AND SEAS WILL REACH A PEAK ON FRIDAY AFTERNOON...THEN GUSTY NORTH WINDS WILL CONTINUE AND SEAS ARE LIKELY TO REMAIN STEEP TO VERY STEEP THROUGH THE WEEKEND. AS A RESULT...A GALE WATCH HAS BEEN FOR THE OUTER WATERS SOUTH OF CAPE BLANCO FROM LATE SATURDAY MORNING THROUGH SUNDAY EVENING. CONFIDENCE IS MODERATE AS THE MAJORITY BUT NOT ALL OF THE MODELS HAVE TRENDED SLIGHTLY STRONGER WITH WEEKEND WINDS...ESPECIALLY ON SUNDAY. WINDS AND SEAS WILL BEGIN TO TREND WEAKER ON MONDAY AND ARE EXPECTED TO DIMINISH INTO WEDNESDAY. -DW/CC && .PREV DISCUSSION... /ISSUED 254 PM PDT THU MAY 5 2016/ DISCUSSION...THIS AFTERNOON THROUGH FRIDAY NIGHT...WATER VAPOR IMAGERY IS SHOWING AN UPPER LEVEL LOW PRESSURE SYSTEM OFF THE CENTRAL CALIFORNIA COAST THIS AFTERNOON. A STRONG BLOCKING PATTERN DOWNSTREAM OF THIS SYSTEM IS KEEPING IT FROM MOVING MUCH. HOWEVER, IT WILL CONTINUE TO SLOWLY EDGE EASTWARD OVER THE NEXT 24 HOURS...THEN MOVE INTO SOUTHERN NEVADA BY FRIDAY EVENING. DEEP MID-UPPER LEVEL SOUTHERLY FLOW IN ADVANCE OF THIS SYSTEM BROUGHT VERY MOIST, UNSTABLE AIR INTO NORTHERN CALIFORNIA AND SOUTHERN OREGON YESTERDAY INTO THIS MORNING, WHICH CONTRIBUTED TO PLENTY OF SHOWERS AND THUNDERSTORMS OVER THE AREA. MULTIPLE SHORT WAVE DISTURBANCE WILL CONTINUE TO ROTATE AROUND THIS UPPER LOW AND MOVE ACROSS THE AREA, PRODUCING MORE SHOWERS AND THUNDERSTORMS. THE MID-UPPER FLOW ACROSS THE AREA IS IN THE PROCESS OF SHIFTING AND WILL BECOME ALMOST DUE EAST BY FRIDAY. AS A RESULT, THE FLOW ALOFT IS MUCH WEAKER TODAY THAN IT WAS YESTERDAY AND STORM MOTIONS THIS AFTERNOON/EVENING WILL BE MUCH SLOWER. RAINFALL RATES OF 0.50-1.00/HOUR ARE POSSIBLE IN SOME OF THE LONGER-LIVED CELLS, WHICH COULD RESULT IN HIGHER THAN USUAL RUNOFF. FOR THIS REASON, WE HAVE ISSUED A FLASH FLOOD WATCH WITH THE POTENTIAL FOR VERY HEAVY RAINFALL IN PORTIONS OF SOUTHERN SISKIYOU COUNTY THIS AFTERNOON THROUGH FRIDAY EVENING. THE FLASH FLOOD THREAT ALSO EXISTS EASTWARD INTO PORTIONS OF MODOC, EASTERN KLAMATH AND LAKE COUNTIES, BUT EXPECT THE BEST CHANCE FOR FLASH FLOODING THERE TO BE THIS EVENING AS ACTIVITY FROM NW NEVADA ARRIVES...AND THEN AGAIN FRIDAY AS MODELS PEG THAT AREA TO BE HIT WITH MUCH HIGHER QPF. WE SHOULD SEE ACTIVITY WANE FOR A WHILE TONIGHT DUE TO THE DIURNAL DROP OFF IN INSTABILITY. ON FRIDAY, THE STORM PREDICTION CENTER HAS PORTIONS OF THE AREA, MOSTLY FROM AROUND KLAMATH FALLS EASTWARD, IN A MARGINAL RISK FOR SEVERE THUNDERSTORMS. MODELS ARE SHOWING SUFFICIENT INSTABILITY TO SUPPORT SUSTAINED CELLS WITH CAPE OF 750-1500 J/KG AND VERY STEEP MID-LEVEL LAPSE RATES (7-8C/KM). WE HAVE ADDED GUSTY WINDS AND HAIL TO THE GRIDDED FORECASTS TO ACCOUNT FOR THIS POTENTIAL. EVEN THOUGH STORM MOTIONS SHOULD BE A BIT FASTER FRIDAY, THE HEAVY RAINFALL THREAT PERSISTS IN THE AREAS UNDER THE FLASH FLOOD WATCH. SPILDE SATURDAY THROUGH THURSDAY...THE UPPER LOW WILL SLOWLY MOVE TOWARDS THE DESERT SOUTHWEST ON SATURDAY. IN THE MORNING THE MODELS SHOW LINGERING WRAP AROUND MOISTURE IN NORTHERN CAL AND SOUTHEAST LAKE AND KLAMATH COUNTIES WITH THE BEST CHANCE FOR RAIN IN SOUTHEAST MODOC COUNTY. NONE OF THE MODELS ARE SHOWING MUCH IF ANY INSTABILITY SATURDAY MORNING, SO WE WON`T MENTION ANY THUNDER. HOWEVER WE`LL STILL KEEP A SLIGHT CHANCE IN THE AFTERNOON. THE UPPER LOW WILL CONTINUE TO SLOWLY MOVE INTO THE FOUR CORNERS SUNDAY MORNING AND AN UPPER RIDGE WILL NOSE IN FROM THE WEST, BUT THEN WILL RETREAT WESTWARD SUNDAY AFTERNOON AS A SHORTWAVE MOVES SOUTHEAST INTO EASTERN WASHINGTON. AT THE SURFACE A WEAK FRONT WILL MOVE THROUGH THE NORTHWEST PART OF THE REGION SUNDAY MORNING INCREASING THE ONSHORE FLOW. THE MARINE LATER COULD THICKEN ENOUGH FOR PATCHY DRIZZLE AT THE COAST, OTHERWISE IT WILL REMAIN DRY. ANOTHER SHORTWAVE WILL MOVE INTO EASTERN WASHINGTON AND NORTHEAST OREGON ON MONDAY, BUT THE TRACK IT`S TAKING IS NOT FAVORABLE FOR PRECIPITATION, SO WE`LL KEEP IT DRY. AN UPPER RIDGE WILL BUILD OFF THE COAST TUESDAY WITH A THERMAL TROUGH DEVELOPING AT THE COAST. THE MODELS DIFFER WITH THE DETAILS AFTER TUESDAY, BUT THE PATTERN REMAINS FAVORABLE FOR CONTINUED DRY AND WARM CONDITIONS. -PETRUCELLI && .MFR WATCHES/WARNINGS/ADVISORIES... OR...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR ORZ030-031. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT FRIDAY FOR ORZ022. CA...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR CAZ080>085. PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT FRIDAY FOR PZZ350-356-370-376. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT FRIDAY FOR PZZ350-356-370. GALE WARNING UNTIL 11 PM PDT FRIDAY FOR PZZ356-376. GALE WATCH FROM SATURDAY MORNING THROUGH SUNDAY EVENING FOR PZZ376. $$ CC/CC/CC
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
147 AM EDT WED MAY 4 2016 .SYNOPSIS... AN UPPER LOW WILL DROP INTO THE OHIO VALLEY AND LINGER AROUND THE MID-ATLANTIC FOR REST OF THE WEEK. THIS WILL RESULT IN AN UNSETTLED WEATHER PATTERN WITH PLENTY OF OPPORTUNITIES FOR MUCH NEEDED RAINFALL ACROSS CENTRAL PENNSYLVANIA. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... DEEP EASTERLY FLOW INTO PA PERSISTS BETWEEN COASTAL CAROLINA SFC LOW AND SOUTHEAST CANADA SFC HIGH CIRCULATIONS. UPPER LEVEL SHEAR AXES CONTINUE TO ROTATE OVER PA IN THE SOUTHWEST FLOW ALOFT AROUND NRN GLAKS UPPER LOW. THIS WAS RESULTING IN A DAMP EVENING THROUGHOUT WITH ISOLATED TO SCATTERED SHOWER ACTIVITY EARLIER THIS EVENING...AND AN INCREASE IN LOW CLOUDS...DRIZZLE AND SPRITZY SHOWERS ELSEWHERE ACROSS CENTRAL PA AS THE NIGHT WEARS ON. ANOTHER UPPER SHEAR AXIS SLOWLY SWINGING INTO THE EASTERN GLAKS AND WESTERN PA WILL KEEP SLGT CHC TO CHC POPS GOING OVERNIGHT BUT DO NOT EXPECT ANY SIGNIFICANT PRECIPITATION. HRRR KEEPS MOST NUMEROUS AND PERSISTENT SHOWERS ACROSS THE SOUTH AND SOUTHEAST WHERE DEEP LAYER MOISTURE IS IN EXCESS OF 0.8"...AND DEEPER MARINE FLOW PERSISTS. LOW CLOUDS WILL REMAIN AND EXPAND ACROSS THE AREA OVERNIGHT. AFOREMENTIONED LIGHT SHOWERS AND AREAS OF DZ CAN BE EXPECTED OVER MOST AREAS THROUGH SUNRISE. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... UPPER LOW OVER CENTRAL CANADA WILL SLIDE INTO THE UPPER OH VLY AND KEEP IT UNSETTLED THROUGH THE PERIOD. POPS ON WED REFLECT THE NORMAL OUTCOME OF AN UPPER LOW OVER OH/WV. SCT SHRA...WITH THE HIGHER /LOW LIKELY/ POPS SLIDE FROM E-W AS THE MORE DRIZZLY STUFF IS JOINED BY DIURNAL CONVECTION OVER THE WRN MTNS. MAXES SHOULD BE ABOUT 5-10F UNDER NORMALS DUE TO LOTS OF CLOUDS AND PROXIMITY OF THE UPPER LOW TO OUR WEST. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MODELS IN DECENT AGREEMENT FOR A LARGE TROUGH OVER EASTERN U.S. TO BECOME DOMINATED BY A CLOSED UPPER LOW DROPPING SOUTH ACROSS THE GREAT LAKES AND CURLING EASTWARD TO BE LOCATED OVER E NORTH CAROLINA BY THU EVE AND DELMARVA ON FRI. SHOWERY PATTERN IN STORE FOR SURE OVER THIS PERIOD...WITH HEAVIEST PRECIP ON THU LOCATED OVER W PA /CLOSER TO UPPER LOW/ WITH PRECIP SHIFTING EASTWARD ON FRI AS IT CONSOLIDATES NEAR SFC LOW PRES OFF THE MID ATLANTIC COAST. THERE LOOKS TO BE A BRIEF BREAK IN SHOWER ACTIVITY ON SATURDAY ALONG WITH A MODEST SPIKE IN TEMPERATURES BEFORE A COLD FRONT SWEEPS SEWD LATER SATURDAY INTO EARLY SUNDAY AS THE PERSISTENT UPPER LOW GRADUALLY UNWINDS. BEHIND THE FRONT...PROGRESSIVE UPPER TROUGH SLIDES THROUGH BRINGING A SHOT OF COOLER AIR FOR SUN/MON BEFORE WHAT LOOKS LIKE COULD BE A PRETTY DECENT WARMUP AS RIDGING FINALLY ARRIVES. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... SOME PATCHY LIGHT RAIN AT UNV EARLIER...BUT CENTRAL AREAS NOT BAD NOW. STILL SOME RAIN ACROSS THE FAR EAST...MAINLY SE. SKIES CLEAR TO THE WEST AT SITES LIKE JST...BUT BFD HAS DENSE FOG. EXPECT SOME IMPROVEMENT BY LATE MORNING ACROSS MUCH OF THE AREA...AS WE WILL BE BETWEEN THE COASTAL SYSTEM AND THE COLD FRONT TO THE WEST...BUT EASTERN AREAS MAY STAY IFR AND MVFR FOR MOST OF THE DAY. SHOWERS AND RAIN BECOME MORE WIDESPREAD WED NIGHT. SOME ADJUSTMENTS MADE TO THE 06Z TAFS. OUTLOOK... THU-FRI...OCNL SHOWERS/RESTRICTIONS POSSIBLE. SAT...NO SIG WX EXPECTED. SUN...SCATTERED SHOWERS/RESTRICTIONS POSSIBLE...ESPECIALLY WEST. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DEVOIR SHORT TERM...DANGELO LONG TERM...RXR/STEINBUGL AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1022 PM EDT THU MAY 5 2016 .SYNOPSIS... UNSEASONABLY COOL AIR WILL CONTINUE TO FILTER IN FROM THE NORTHWEST IN THE WAKE OF A COLD FRONT. THE WEATHER WILL REMAIN UNSETTLED AS A DEEP UPPER LOW CENTER MOVES ACROSS THE CAROLINAS TONIGHT AND AWAY TO THE NORTHEAST ON FRIDAY. ANOTHER FRONT IS EXPECTED TO STALL JUST TO OUR NORTH ON SATURDAY AND SUNDAY. THE FRONT SHOULD LIFT BACK TO THE NORTH ON MONDAY...AS HIGH PRESSURE OFF THE SOUTHEAST COAST EXPANDS AND WARM SOUTHERLY FLOW RETURNS. && .NEAR TERM /THROUGH FRIDAY/... AS OF 1015 PM EDT...ABUNDANT MOISTURE MOVING SOUTHWARD ALONG THE SPINE OF THE MOUNTAINS IS ENCOUNTERING WET BULB PROFILES JUST COLD ENOUGH ABOVE ABOUT 4000 FEET TO CHANGE THE PREDOMINANT PRECIPITATION TYPE OVER TO SNOW. ALTHOUGH THERE ARE MODEL HINTS OF SLIGHT WARMING OVERNIGHT...IF ALL OR MOST OF THE IMPENDING QPF IS PREDOMINATELY SNOW AT THE HIGHER ELEVATIONS...ENOUGH ACCUMULATION SHOULD DEVELOP FOR SLIPPERY ROADWAYS AND ASSOCIATED IMPACTS TO MANIFEST THEMSELVES. A WINTER WEATHER ADVISORY HAS BEEN POSTED FOR AVERY AND MITCHELL COUNTIES ABOVE 3500 FEET AT THIS POINT. THE ELEVATION DEPENDENCE WILL BE STRONG...WITH MAINLY RAIN BELOW 3500 FEET...ABOUT AN INCH AT 3500 FEET RANGING UP TO SIX INCHES ABOVE 5000 FEET. OTHERWISE...WATER VAPOR IMAGERY AND RAP 500 MB HEIGHTS CONTINUE TO INDICATE THAT THE 546 DM LOW CENTER HAS MOVED EAST OF THE CLT METRO AREA. MOISTURE AND SPOKES OF 500 MB VORTICITY CONTINUE TO ROTATE SOUTH ACROSS THE FORECAST AREA AROUND THE BACK SIDE OF THE LOW PRESSURE SYSTEM. THIS WILL LEAD TO FAIRLY HIGH COVERAGE OF LIGHT RAIN/SHOWERS ACROSS THE NORTHERN TIER...WITH ELEVATIONS ABOVE ABOUT 4000 FEET COLD ENOUGH FOR SNOW AT TIMES IN THE NORTHERN MOUNTAINS. SOME WARMING IS POSSIBLE OVERNIGHT. THE SHOWER COVERAGE WILL BE MUCH SPOTTIER IN SOUTHERN SECTIONS WITH MAINLY PERIODS OF CLOUDS. THE LOW WILL MOVE TOWARD THE CAROLINA COAST OVERNIGHT INTO FRIDAY...AND THE BEST Q VECTOR CONVERGENCE WILL BE TO OUR EAST. THE SETUP WILL BE SOMEWHAT SIMILAR ON FRIDAY...AS THE LOW REMAINS OVER THE MID-ATLANTIC COAST. LAPSE RATES WILL BE SLIGHTLY POORER WITH THE BETTER COLD AIR OFF TO THE EAST...BUT TEMPS/DEWPTS REBOUND BY 5-7 DEGREES...AND THESE SUGGEST SOME INSTABILITY WILL REDEVELOP. CHANCES OVERALL ARE LESSER WITH MODEL QPF BEING LESS WIDESPREAD. BREEZY TO WINDY CONDITIONS WILL RESULT WITH DEEP MIXING. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... AS OF 225 PM THURSDAY...ONE MORE POCKET OF COLD AIR ROTATES AROUND THE UPPER LOW AND ACROSS THE AREA FRIDAY NIGHT BEFORE WARMER MID LEVEL AIR MOVES IN ON SATURDAY. THIS WILL COMBINE WITH THE LINGERING LOW LEVEL MOISTURE ACROSS THE MOUNTAINS TO KEEP ISOLATED TO SCATTERED SHOWERS THERE DURING THE EVENING BEFORE ENDING BY MIDNIGHT. A WEAK WARM FRONT TRAILING FROM A SURFACE LOW OVER THE GREAT LAKES WILL BRUSH THE MOUNTAINS ON SATURDAY CREATING THE POTENTIAL FOR ISOLATED SHOWERS. FINALLY...A BACK DOOR COLD FRONT DROPS INTO THE AREA BY SUNDAY AS THE GREAT LAKES LOW MOVES EAST. SOME WEAK SHORT WAVE ENERGY WILL CROSS THE AREA SATURDAY NIGHT AND SUNDAY EVEN AS HEIGHTS RISE BETWEEN THE DEPARTING UPPER LOW AND A RIDGE DEVELOPING OVER THE CENTRAL CONUS. BEST CHANCE FOR CONVECTION WILL BE THE NORTHERN NC MOUNTAINS...WITH ISOLATED CONVECTION POSSIBLE ACROSS THE I-40 CORRIDOR. TEMPS REBOUND TO NEAR NORMAL LEVELS ON SATURDAY THEN RISE TO NEARLY 10 DEGREES ABOVE NORMAL ON SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 245PM THURSDAY...THE EXTENDED PERIOD BEGINS SUNDAY NIGHT WITH A STALLED FRONTAL BOUNDARY DRAPED W TO E ACROSS THE REGION UNDERNEATH FAIRLY ZONAL FLOW ALOFT. THE BOUNDARY WILL RETREAT NORTH AS A WARM FRONT AS SUBTROPICAL HIGH PRESSURE OVER THE SARGASSO SEA INDUCES WARM SOUTHERLY FLOW ACROSS THE REGION BEGINNING MONDAY AFTERNOON AND PERSISTING THROUGH AT LEAST WEDNESDAY. THE RETURN FLOW WILL ALLOW TEMPERATURES TO QUICKLY REBOUND TO GENERALLY 5-10 DEGREES ABOVE NORMAL THROUGH MID TO LATE WEEK. DEWPOINTS WILL GRADUALLY RETURN TO THE UPPER 50S AND LOWER 60S DURING THIS TIME AS WELL AND WITH THE INCREASING DIURNAL INSTABILITY...THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY. THE ECMWF REMAINS LESS OPTIMISTIC ABOUT COVERAGE THROUGH MID-WEEK WHILE THE GFS MAINTAINS SCATTERED TO WIDESPREAD COVERAGE EACH AFTERNOON. THIS APPEARS LARGELY TO BE THE RESULT OF STRONGER PERTURBATIONS IN THE WSW FLOW ALOFT ENHANCING OVERALL FORCING IN THE GFS COMPARED TO THE FAIRLY BENIGN ECMWF SOLUTION. THE FORECAST THEREFORE REFLECTS A BLEND OF THE GUIDANCE AS THE PATTERN CERTAINLY WARRANTS SLIGHT CHANCE COVERAGE EAST AND CHANCE COVERAGE WEST. AN OPPORTUNITY EXISTS FOR MORE WIDESPREAD COVERAGE OF SHOWERS AND STORMS WEDNESDAY EVENING INTO FRIDAY AS ANOTHER CLOSED LOW DROPS INTO THE UPPER MIDWEST AND GREAT LAKES REGIONS AND A FEW LOBES OF VORTICITY ROTATE AROUND THE BASE OF THE LOW ACROSS THE OH AND TN VALLEYS AND INTO VIRGINIA AND THE CAROLINAS. HOWEVER...GIVEN THE SOMEWHAT ANOMALOUS NATURE OF THIS PATTERN...AGAIN THE GUIDANCE DIFFERS ON THE EXACT PLACEMENT AND EVOLUTION OF THE UPPER-LEVEL FLOW. WHILE POPS INCREASE SLIGHTLY INTO LATE WEEK IN RESPONSE TO THE ANTICIPATED BETTER FORCING ALOFT...THERE IS TOO MUCH UNCERTAINTY TO WARRANT MORE AGGRESSIVE COVERAGE ATTM. FOR NOW...THESE FEATURES DO LITTLE TO CHANGE THE ABOVE NORMAL TEMPERATURES WE EXPECT THROUGH THE END OF NEXT WEEK. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... AT KCLT...OCCASIONAL SHOWERS CONTINUE TO PIVOT SOUTHWARD TOWARD THE AIRFIELD AROUND THE BACK SIDE OF THE UPPER LEVEL LOW PRESSURE SYSTEM. DAYTIME INSTABILITY HAS WEAKENED ENOUGH THAT ANY ADDITIONAL SHOWERS WILL LIKELY NOT CONTAIN SMALL HAIL. MAINLY VFR CIGS ARE EXPECTED...BUT MVFR CIGS COULD APPROACH FROM THE NORTH IN THE BETTER LOW LEVEL MOISTURE OVERNIGHT. ALTHOUGH MIXING IS NOT QUITE AS DEEP...GUSTY NORTH WINDS WILL CONTINUE FOR A FEW HOURS INTO THE OVERNIGHT. SHRA CHANCES WILL STEADILY DIMINISH OVERNIGHT INTO FRIDAY MORNING...BUT LAPSE RATES WILL REMAIN SUFFICIENT FOR PROB30 CHANCES TO RETURN FOR FRIDAY AFTERNOON. DEEP MIXING WILL PERMIT GUSTY CONDITIONS ONCE AGAIN...WITH PEAK GUSTS 20 TO 30 KT POSSIBLE AS THE PRESSURE GRADIENT TIGHTENS A BIT. ELSEWHERE...THE NORTHERN TIER FROM KAVL TO KHKY WILL SEE THE BEST CHANCES OF MOISTURE AND SHRA WRAPPING SOUTHWARD TOWARD THE AIRFIELDS. MVFR CIGS LOOK LIKELY AS THE RAIN CONTINUES TO FALL...BUT WITH MUCH LESS CHANCE OF SHRA AND LOWERING CIGS FARTHER SOUTH AT THE SC TAF SITES. GUSTY CONDITIONS WILL ABATE OVERNIGHT EAST OF THE MOUNTAINS BUT CONTINUE AT KAVL. DEEP MIXING WILL PERMIT GUSTS OF 20 TO 30 KT...POSSIBLY 35 KT AT KAVL...ON FRIDAY. ANOTHER ROUND OF SCATTERED SHOWERS IS LIKELY THROUGH FRIDAY AFTERNOON AS STEEP LAPSE RATES ALOFT PERSIST. OUTLOOK...PROFILES WILL GRADUALLY DRY FRIDAY NIGHT INTO SATURDAY. A COLD FRONT WILL APPROACH FROM THE NORTH THROUGH SUNDAY...WITH ASSOCIATED PRECIPITATION POSSIBLY APPROACHING KAVL TO KHKY BEFORE THE FRONT STALLS. WARMING CONDITIONS WITH A RETURN TO SW FLOW ARE EXPECTED THROUGH EARLY NEXT WEEK. CONFIDENCE TABLE... 02-08Z 08-14Z 14-20Z 20-00Z KCLT MED 67% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL MED 71% MED 62% HIGH 100% HIGH 100% KHKY LOW 56% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULE TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLET HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...WINTER WEATHER ADVISORY UNTIL NOON EDT FRIDAY FOR NCZ033-050. SC...NONE. && $$ SYNOPSIS...HG/JMP NEAR TERM...HG SHORT TERM...RWH LONG TERM...JMP AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
805 PM EDT THU MAY 5 2016 .SYNOPSIS... UNSEASONABLY COOL AIR WILL CONTINUE TO FILTER IN FROM THE NORTHWEST IN THE WAKE OF A COLD FRONT. THE WEATHER WILL REMAIN UNSETTLED AS A DEEP UPPER LOW CENTER MOVES ACROSS THE CAROLINAS TONIGHT AND AWAY TO THE NORTHEAST ON FRIDAY. ANOTHER FRONT IS EXPECTED TO STALL JUST TO OUR NORTH ON SATURDAY AND SUNDAY. THE FRONT SHOULD LIFT BACK TO THE NORTH ON MONDAY...AS HIGH PRESSURE OFF THE SOUTHEAST COAST EXPANDS AND WARM SOUTHERLY FLOW RETURNS. && .NEAR TERM /THROUGH FRIDAY/... AS OF 745 PM EDT...WATER VAPOR IMAGERY AND RAP 500 MB HEIGHTS INDICATE THAT THE 546 DM LOW CENTER HAS MOVED EAST OF THE CLT METRO AREA. MOISTURE AND SPOKES OF 500 MB VORTICITY CONTINUE TO ROTATE SOUTH ACROSS THE FORECAST AREA AROUND THE BACK SIDE OF THE LOW PRESSURE SYSTEM. THIS WILL LEAD TO FAIRLY HIGH COVERAGE OF LIGHT RAIN/SHOWERS ACROSS THE NORTHERN TIER...WITH ELEVATIONS ABOVE 4500 FEET COLD ENOUGH FOR SNOW AT TIMES IN THE NORTHERN MOUNTAINS. MOST OF THE HIGHER MOUNTAIN VALLEYS WILL EXHIBIT WET BULB PROFILES ABOVE FREEZING IN THE LOWEST 1500 TO 2000 FEET...SO MOSTLY RAIN IS EXPECTED THERE. STILL...AN SPS HAS BEEN ISSUED FOR 1 TO 2 INCHES OF SNOW POSSIBLE ABOVE 5000 FEET WHICH WILL LEAD TO SLIPPERY ROAD CONDITIONS WITH TEMPS CURRENTLY 30 TO 32 DEGREES. OTHERWISE...SHOWER COVERAGE WILL BE MUCH SPOTTIER IN SOUTHERN SECTIONS WITH MAINLY PERIODS OF CLOUDS AND CONTINUED BREEZY CONDITIONS. THE LOW WILL MOVE TOWARD THE CAROLINA COAST OVERNIGHT INTO FRIDAY...AND THE BEST Q VECTOR CONVERGENCE WILL BE TO OUR EAST. THE SETUP WILL BE SOMEWHAT SIMILAR ON FRIDAY...AS THE LOW REMAINS OVER THE MID-ATLANTIC COAST. LAPSE RATES WILL BE SLIGHTLY POORER WITH THE BETTER COLD AIR OFF TO THE EAST...BUT TEMPS/DEWPTS REBOUND BY 5-7 DEGREES...AND THESE SUGGEST SOME INSTABILITY STILL WILL DEVELOP. CHANCES OVERALL ARE LESSER WITH MODEL QPF BEING LESS WIDESPREAD. BREEZY TO WINDY CONDITIONS WILL RESULT WITH DEEP MIXING. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... AS OF 225 PM THURSDAY...ONE MORE POCKET OF COLD AIR ROTATES AROUND THE UPPER LOW AND ACROSS THE AREA FRIDAY NIGHT BEFORE WARMER MID LEVEL AIR MOVES IN ON SATURDAY. THIS WILL COMBINE WITH THE LINGERING LOW LEVEL MOISTURE ACROSS THE MOUNTAINS TO KEEP ISOLATED TO SCATTERED SHOWERS THERE DURING THE EVENING BEFORE ENDING BY MIDNIGHT. A WEAK WARM FRONT TRAILING FROM A SURFACE LOW OVER THE GREAT LAKES WILL BRUSH THE MOUNTAINS ON SATURDAY CREATING THE POTENTIAL FOR ISOLATED SHOWERS. FINALLY...A BACK DOOR COLD FRONT DROPS INTO THE AREA BY SUNDAY AS THE GREAT LAKES LOW MOVES EAST. SOME WEAK SHORT WAVE ENERGY WILL CROSS THE AREA SATURDAY NIGHT AND SUNDAY EVEN AS HEIGHTS RISE BETWEEN THE DEPARTING UPPER LOW AND A RIDGE DEVELOPING OVER THE CENTRAL CONUS. BEST CHANCE FOR CONVECTION WILL BE THE NORTHERN NC MOUNTAINS...WITH ISOLATED CONVECTION POSSIBLE ACROSS THE I-40 CORRIDOR. TEMPS REBOUND TO NEAR NORMAL LEVELS ON SATURDAY THEN RISE TO NEARLY 10 DEGREES ABOVE NORMAL ON SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 245PM THURSDAY...THE EXTENDED PERIOD BEGINS SUNDAY NIGHT WITH A STALLED FRONTAL BOUNDARY DRAPED W TO E ACROSS THE REGION UNDERNEATH FAIRLY ZONAL FLOW ALOFT. THE BOUNDARY WILL RETREAT NORTH AS A WARM FRONT AS SUBTROPICAL HIGH PRESSURE OVER THE SARGASSO SEA INDUCES WARM SOUTHERLY FLOW ACROSS THE REGION BEGINNING MONDAY AFTERNOON AND PERSISTING THROUGH AT LEAST WEDNESDAY. THE RETURN FLOW WILL ALLOW TEMPERATURES TO QUICKLY REBOUND TO GENERALLY 5-10 DEGREES ABOVE NORMAL THROUGH MID TO LATE WEEK. DEWPOINTS WILL GRADUALLY RETURN TO THE UPPER 50S AND LOWER 60S DURING THIS TIME AS WELL AND WITH THE INCREASING DIURNAL INSTABILITY...THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY. THE ECMWF REMAINS LESS OPTIMISTIC ABOUT COVERAGE THROUGH MID-WEEK WHILE THE GFS MAINTAINS SCATTERED TO WIDESPREAD COVERAGE EACH AFTERNOON. THIS APPEARS LARGELY TO BE THE RESULT OF STRONGER PERTURBATIONS IN THE WSW FLOW ALOFT ENHANCING OVERALL FORCING IN THE GFS COMPARED TO THE FAIRLY BENIGN ECMWF SOLUTION. THE FORECAST THEREFORE REFLECTS A BLEND OF THE GUIDANCE AS THE PATTERN CERTAINLY WARRANTS SLIGHT CHANCE COVERAGE EAST AND CHANCE COVERAGE WEST. AN OPPORTUNITY EXISTS FOR MORE WIDESPREAD COVERAGE OF SHOWERS AND STORMS WEDNESDAY EVENING INTO FRIDAY AS ANOTHER CLOSED LOW DROPS INTO THE UPPER MIDWEST AND GREAT LAKES REGIONS AND A FEW LOBES OF VORTICITY ROTATE AROUND THE BASE OF THE LOW ACROSS THE OH AND TN VALLEYS AND INTO VIRGINIA AND THE CAROLINAS. HOWEVER...GIVEN THE SOMEWHAT ANOMALOUS NATURE OF THIS PATTERN...AGAIN THE GUIDANCE DIFFERS ON THE EXACT PLACEMENT AND EVOLUTION OF THE UPPER-LEVEL FLOW. WHILE POPS INCREASE SLIGHTLY INTO LATE WEEK IN RESPONSE TO THE ANTICIPATED BETTER FORCING ALOFT...THERE IS TOO MUCH UNCERTAINTY TO WARRANT MORE AGGRESSIVE COVERAGE ATTM. FOR NOW...THESE FEATURES DO LITTLE TO CHANGE THE ABOVE NORMAL TEMPERATURES WE EXPECT THROUGH THE END OF NEXT WEEK. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... AT KCLT...OCCASIONAL SHOWERS CONTINUE TO PIVOT SOUTHWARD TOWARD THE AIRFIELD AROUND THE BACK SIDE OF THE UPPER LEVEL LOW PRESSURE SYSTEM. DAYTIME INSTABILITY HAS WEAKENED ENOUGH THAT ANY ADDITIONAL SHOWERS WILL LIKELY NOT CONTAIN SMALL HAIL. MAINLY VFR CIGS ARE EXPECTED...BUT MVFR CIGS COULD APPROACH FROM THE NORTH IN THE BETTER LOW LEVEL MOISTURE OVERNIGHT. ALTHOUGH MIXING IS NOT QUITE AS DEEP...GUSTY NORTH WINDS WILL CONTINUE FOR A FEW HOURS INTO THE OVERNIGHT. SHRA CHANCES WILL STEADILY DIMINISH OVERNIGHT INTO FRIDAY MORNING...BUT LAPSE RATES WILL REMAIN SUFFICIENT FOR PROB30 CHANCES TO RETURN FOR FRIDAY AFTERNOON. DEEP MIXING WILL PERMIT GUSTY CONDITIONS ONCE AGAIN...WITH PEAK GUSTS 20 TO 30 KT POSSIBLE AS THE PRESSURE GRADIENT TIGHTENS A BIT. ELSEWHERE...THE NORTHERN TIER FROM KAVL TO KHKY WILL SEE THE BEST CHANCES OF MOISTURE AND SHRA WRAPPING SOUTHWARD TOWARD THE AIRFIELDS. MVFR CIGS LOOK LIKELY AS THE RAIN CONTINUES TO FALL...BUT WITH MUCH LESS CHANCE OF SHRA AND LOWERING CIGS FARTHER SOUTH AT THE SC TAF SITES. GUSTY CONDITIONS WILL ABATE OVERNIGHT EAST OF THE MOUNTAINS BUT CONTINUE AT KAVL. DEEP MIXING WILL PERMIT GUSTS OF 20 TO 30 KT...POSSIBLY 35 KT AT KAVL...ON FRIDAY. ANOTHER ROUND OF SCATTERED SHOWERS IS LIKELY THROUGH FRIDAY AFTERNOON AS STEEP LAPSE RATES ALOFT PERSIST. OUTLOOK...PROFILES WILL GRADUALLY DRY FRIDAY NIGHT INTO SATURDAY. A COLD FRONT WILL APPROACH FROM THE NORTH THROUGH SUNDAY...WITH ASSOCIATED PRECIPITATION POSSIBLY APPROACHING KAVL TO KHKY BEFORE THE FRONT STALLS. WARMING CONDITIONS WITH A RETURN TO SW FLOW ARE EXPECTED THROUGH EARLY NEXT WEEK. CONFIDENCE TABLE... 00-06Z 06-12Z 12-18Z 18-00Z KCLT MED 77% HIGH 91% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 80% MED 65% HIGH 93% HIGH 100% KHKY MED 70% HIGH 93% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULE TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLET HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...HG/JMP NEAR TERM...HG SHORT TERM...RWH LONG TERM...JMP AVIATION...HG
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
709 PM CDT THU MAY 5 2016 .UPDATE... FOR 00Z AVIATION DISCUSSION. && .DISCUSSION... UPPER LOW POSITIONED OVER THE CAROLINAS THIS EVENING. A VERTICALLY STACKED NORTHERLY FLOW KEEPING CONDITIONS ON THE COOL SIDE. CLOUD COVER...ALSO NOTED ON THE BACKSIDE OF THE TROUGH AXIS AND IS KEEPING A MOSTLY CLOUDY SKY ACROSS THE NORTHEASTERN TWO THIRDS OF THE MID STATE. THE TREND WILL BE FOR THESE CLOUDS TO DECREASE BUT IT MAY TAKE A FEW HOURS BEFORE THAT REALLY HAPPENS. THUS...WILL NOTCH UP THE INITIAL CLOUD COVER AND INTERPOLATE TOWARD A MOSTLY CLEAR NIGHT. WILL THEN REISSUE ZONES. OTW...REMAINDER OF FCST IN GOOD SHAPE. WINDS WILL SLOWLY DECREASE OVERNIGHT. && .AVIATION... 00Z TAF DISCUSSION. PER ABOVE MENTIONED DISCUSSION...LOOKING FOR A DECREASING CLOUDINESS TREND TO COMMENCE...BUT IT MAY TAKE A FEW HRS BEFORE THAT REALLY HAPPENS. DO EXPECT NW SFC GUSTS TO 18-20KTS TO DISSIPATE BNA BY AROUND 06/02Z PER WEAKENING SFC PRESSURE GRADIENT INFLUENCES ALONG DIURNAL MIXING INFLUENCES ENDING. BREAKAGE IN BKN/OVC STRATO CU COVERAGE NOTED ACROSS SRN OHIO VALLEY REGION...BUT AM HESITANT...ESPECIALLY WITH LATEST HRRR LOW LEVEL ATM MOISTURE PROFILES SUPPORTIVE OF BKN CLOUD COVERAGE NOT DISSIPATING AT CKV UNTIL AROUND 06/10Z...BNA 06/12Z...AND CSV 06/15Z. WILL LEAN TOWARD MORE PESSIMISTIC HRRR CLOUD COVERAGE EROSION TIMEAGE PER PREVIOUS FORECAST HISTORY ACROSS MID STATE PER SIMILAR EVENTS...BUT WOULD CERTAINLY NOT BE SURPRISED TO SEE CEILING EROSIONS AT ALL TERMINALS OCCUR SOONER. IF EROSIONS OCCUR EARLY ENOUGH...ESPECIALLY CSV...SOME MVFR/IFR FOG INDUCED VSBYS/SIMILAR LOW STRATUS CEILINGS COULD OCCUR PER PERSISTENT LOW LEVEL MOISTURE POOLING POTENTIAL BEING PRESENT ACROSS THIS AREA OVER PAST 24+ HRS...ALONG WITH CLRING SKIES/LIGHT WINDS. ADDRESSED POSSIBILITY WITH PREVAILING MVFR VSBYS/CEILINGS 06/08Z-06/15Z. OTHERWISE... BUILDING RIDGING INFLUENCES SFC/ALOFT TO PROVIDE VFR/SKC CONDITIONS AT ALL TERMINALS 06/14Z-06/24Z WITH NW/N SFC WINDS 5-10KTS. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM/AVIATION........31 LONG TERM..................21
AREA FORECAST DISCUSSION
NWS SEATTLE WA
845 PM PDT THU MAY 5 2016 .SYNOPSIS...HIGH PRESSURE ALOFT WILL BUILD OVER THE REGION FRIDAY AND SATURDAY PROVIDING INCREASED SUNSHINE AND A RETURN TO ABOVE NORMAL TEMPERATURES. A TROUGH WILL INDUCE MUCH COOLER ONSHORE FLOW SATURDAY NIGHT THROUGH MONDAY WITH SOME DRIZZLE OR SHOWERS POSSIBLE. DRY AND WARMER WEATHER RETURNS TUESDAY THROUGH THURSDAY. && .SHORT TERM...MOST CLOUDS HAVE GONE FROM WESTERN WASHINGTON EXCEPT FOR IN THE CASCADES. THERE HAVE BEEN ISOLATED SHOWERS NEAR THE CASCADE CREST THIS EVENING BUT ANY LIGHTNING APPEARS TO BE EAST OF THE CREST. WHITE PASS GOT JUST OVER A TENTH OF AN INCH IN A SHOWER. THE SLOW TREND OF THE LAST DAY OR SO WILL CONTINUE...CLEARING FROM THE WEST AND AN END TO THE CASCADE SHOWERS. FRIDAY WILL BE DRY WITH HIGH PRESSURE ALOFT. SURFACE FLOW NEVER BECOMES STRONGLY OFFSHORE BUT NORTH FLOW OFF THE WATER WILL BE LIGHTER THAN TODAY AND 500 MB HEIGHTS RISE OVER 5700M. THIS SHOULD ALLOW MOST AREAS TO REACH INTO THE 70S EXCEPT THE USUAL LOCALLY COOLER SPOTS AROUND THE SAN JUANS AND PARTS OF THE STRAIT. THE CASCADE FOOTHILLS AND SW INTERIOR AWAY FROM THE WATER COULD HIT THE LOW 80S IN A FEW SPOTS. DRY WEATHER PERSISTS INTO SATURDAY BUT AN UPPER TROUGH WILL BE APPROACHING THE REGION FROM THE NORTHWEST. BEST BET IS FOR ANOTHER WARM DAY SATURDAY FOLLOWED BY A STRONG MARINE PUSH SATURDAY NIGHT. MODELS SHOW SPOTTY LIGHT QPF AND IMPLY SOME DRIZZLE IS POSSIBLE WITH THE PUSH LATER SATURDAY NIGHT AND SUNDAY. LOCATIONS THAT DO MEASURE WILL ONLY SEE VERY LIGHT AMOUNTS...PROBABLY NO MORE THAN A FEW HUNDREDTHS. THE CLOUDS MAY REMAIN THROUGH THE DAY UNDER A DEEP MARINE LAYER AND STRONG ONSHORE FLOW. HIGHS WILL BE IN THE UPPER 50S AND LOW 60S. MERCER/BURKE .LONG TERM...PREVIOUS DISCUSSION...THE GFS AND ECMWF DIG ADDITIONAL UPPER LEVEL ENERGY ACROSS WRN WA SUNDAY NIGHT INTO MONDAY. SOME OF THE STRONGER SOLUTIONS SHOW A CLOSED LOW DEVELOPING AND DIGGING SE ACROSS THE CASCADES INTO ERN WA. THIS SHOULD MAINTAIN A MOSTLY CLOUDY AND COOL MARINE AIR MASS OVER WRN WA INTO MONDAY. SOME SHOWERS COULD ALSO LINGER...ESPECIALLY ACROSS THE CASCADES WITH SNOW LEVELS DOWN TO 5000 FEET. MOISTURE STILL LOOKS QUITE LIMITED AND PRECIPITATION AMOUNTS WILL REMAIN LIGHT. IF THE TROUGH PULLS AWAY QUICK ENOUGH DURING THE AFTERNOON...THERE IS A BETTER CHANCE FOR PARTIAL BREAK OUT AND HIGHS COULD WARM A COUPLE DEGREES OVER SUNDAY. LONG RANGE MODELS AGREE ON SOME RIDGING BY TUESDAY AND ESPECIALLY WEDNESDAY. THIS SHOULD PROVIDE DRY WEATHER AND YET ANOTHER WARMING TREND WITH HIGHS LIKELY TO REACH +10F ABOVE AVERAGE. THE ECMWF IS WEAKER WITH THE RIDGE THAN THE GFS/CANADIAN AND SUPPRESSES HEIGHTS BY THURSDAY. THIS COULD INDUCE SOME ONSHORE FLOW AND COOLING. THE AVERAGE OF THE MODELS KEEP A STRONGER RIDGE IN PLACE AND IMPLY CONTINUED WARM CONDITIONS...WELL ABOVE AVERAGE...THROUGH THE END OF THE WEEK. KEPT TEMPERATURES BELOW POTENTIAL HIGHS BUT WARMER THAN THE ECMWF WOULD SUGGEST. HIGHS IN THE 70S ARE A GOOD BET...IF NOT SOME 80S MID TO LATE WEEK. MERCER && .AVIATION...SOUTHERLY FLOW CONTINUES ALOFT OVER WESTERN WASHINGTON AHEAD OF AN UPPER TROUGH THAT IS ALONG THE COAST THIS EVENING. THE FLOW OVER THE OFFSHORE WATERS HAS TURNED NORTHERLY. THE AIR MASS IS GENERALLY DRY EXCEPT FOR MID AND HIGH LEVEL MOISTURE ASSOCIATED WITH CONVECTION OVER THE CASCADES. NORTHWEST ONSHORE FLOW CONTINUES AT LOW LEVELS BUT THERE IS LITTLE MOISTURE IN THE MARINE LAYER. CEILINGS SHOULD REMAIN MOSTLY 12000 FT OR ABOVE TONIGHT AND FRIDAY...EXCEPT PATCHY FOG AND STRATUS AT THE COAST EARLY FRIDAY MORNING. KSEA...NORTH WIND 6-12 KT RISING TO 8-16 KT FRIDAY. CEILINGS SHOULD BE ABOVE 12000 FT. MCDONNAL && .MARINE...NORTHWEST ONSHORE FLOW WILL PERSIST TONIGHT THROUGH MONDAY...WITH HIGH PRESSURE OFFSHORE AND LOW PRESSURE EAST OF THE CASCADES. SMALL CRAFT ADVISORY NORTHWEST WINDS DEVELOPED OVER THE COASTAL WATERS THIS EVENING...AND A SMALL CRAFT ADVISORY HAS BEEN ISSUED. WESTERLY GALES ARE LIKELY IN THE STRAIT OF JUAN DE FUCA SATURDAY EVENING WHEN A STRONG MARINE PUSH WILL OCCUR. MCDONNAL && .SEW WATCHES/WARNINGS/ADVISORIES... WA...NONE. PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT FRIDAY FOR COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10 NM-COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM- COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE OUT 10 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER OUT 10 NM. && $$ WWW.WEATHER.GOV/SEATTLE YOU CAN SEE AN ILLUSTRATED VERSION OF THIS DISCUSSION AT WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
  [top] Area Forecast Discussion National Weather Service Spokane WA 600 PM PDT THU MAY 5 2016 .SYNOPSIS... Isolated showers and thunderstorms will be possible mainly across southeast Washington into the Idaho Panhandle this evening. Some storms will be capable of heavy rainfall...hail...and gusty winds. Improving but breezy conditions will begin on Friday, lasting through the weekend. More unsettled and cooler weather is expected next week. && .DISCUSSION... LAPS analysis as of 5 pm indicated the best instability over SE Washington into the Central Panhandle Mountains as well as the Clearwaters with CAPE VALUES OF 500-1000 J/KG with very minimal convective inhibition. However with the low off the Central CA coast there is no large scale forcing to initiate convection. This should change this evening however for the Camas Prairie, Lewiston area, and Blue Mountains as a couple stronger storms currently producing quite a bit of lightning approach the area...with outflow winds likely inititating new storms as they approach these areas. Will have to monitor potential for gusty winds and small hail as these approach. Further north...across the Spokane/Coeur D`Alene area...North Idaho Panhandle...and much of Central and NE Washington low level northerly winds as well as earlier cloud cover should help to stabilize the air mass this evening. The HRRR shows convection falling apart as it tries to make it into these areas this evening and thus POP`s were lowered for the remainder of tonight. JW && .AVIATION... 00Z TAFS: Main aviation concern is the potential for thunderstorms mainly over southeast Washington and the south Idaho Panhandle this evening which could impact the KLWS/KPUW TAF sites. Thus far the storms are weakening as they come off the Blue Mountains and the HRRR shows storms weakening this evening as they approach the KLWS/KPUW TAF sites. Thus for now confidence is only low to moderate of these sites being impacted and thus thunder was removed for now. However will be monitoring radar trends. Otherwise a tight northerly pressure gradient develops tonight which will result in increasing north-northeast winds especially at KMWH/KCOE by Friday morning. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 54 77 54 81 55 76 / 10 10 10 0 0 10 Coeur d`Alene 49 76 50 81 52 75 / 20 10 10 10 0 10 Pullman 49 75 49 78 51 72 / 20 10 10 10 0 10 Lewiston 53 81 54 83 56 78 / 40 20 10 10 10 10 Colville 45 81 47 85 48 80 / 10 10 10 0 0 10 Sandpoint 47 74 44 79 46 73 / 20 10 10 0 0 20 Kellogg 45 73 44 79 46 72 / 50 10 10 10 0 20 Moses Lake 52 83 53 86 52 80 / 10 10 0 0 0 0 Wenatchee 54 82 57 86 58 77 / 10 10 0 0 0 0 Omak 48 81 53 85 52 79 / 10 10 0 0 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1043 PM PDT THU MAY 5 2016 .SYNOPSIS...AN UPPER LEVEL LOW OFF OF THE CENTRAL CALIFORNIA COAST WILL SHIFT INLAND OVER SOUTHERN CALIFORNIA ON FRIDAY AND RESULT IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH FRIDAY EVENING. SCATTERED SHOWERS WILL LIKELY LINGER INTO SATURDAY WITH DRY WEATHER EXPECTED TO RETURN TO MOST AREAS BY SUNDAY. DRY WEATHER IS THEN FORECAST THROUGH THE MIDDLE OF NEXT WEEK ALONG WITH A GRADUAL WARMING TREND. && .DISCUSSION...AS OF 9:10 PM PDT THURSDAY...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OCCURRED ACROSS PORTIONS OF OUR FORECAST AREA TODAY. THIS CONVECTIVE PRECIPITATION WAS TRIGGERED BY AN UPPER LOW THAT IS CURRENTLY CENTERED ABOUT 100 MILES SOUTHWEST OF MONTEREY. THE MOST SIGNIFICANT RAINFALL TO OCCUR FROM TODAY`S SHOWER ACTIVITY WAS AT PINNACLES NATIONAL PARK WHERE 0.33" WAS RECORDED. IN OTHER LOCATIONS WHERE RAIN FELL TODAY...AMOUNTS WERE MOSTLY LESS THAN A TENTH OF AN INCH. A LINE OF INTENSE SHOWERS AND THUNDERSTORMS DEVELOPED JUST TO THE EAST OF SANTA CLARA AND SAN BENITO COUNTIES LATE THIS AFTERNOON. BUT THIS CONVECTIVE ACTIVITY EITHER WEAKENED CONSIDERABLY OR DISSIPATED AS IT MOVED TO THE NORTHWEST TOWARDS THE SANTA CLARA AND HOLLISTER VALLEYS THIS EVENING. NOW THAT THE SUN HAS SET ALL ACTIVITY HAS DIMINISHED AND EXPECT ONLY ISOLATED SHOWERS OVERNIGHT. THE CUTOFF LOW IS FORECAST TO MOVE GRADUALLY TO THE SOUTHEAST OVERNIGHT AND THEN TURN TO THE EAST AND INLAND OVER SOUTHERN CA ON FRIDAY MORNING. MEANWHILE...A SHORTWAVE TROUGH ROTATING AROUND THE LOW IS FORECAST TO MOVE ACROSS OUR AREA ON FRIDAY MORNING AND EARLY FRIDAY AFTERNOON. THE MODELS ALL SHOW AN ORGANIZED AREA OF PRECIP WITH THIS SHORTWAVE...TRACKING FROM NORTHEAST TO SOUTHWEST ACROSS OUR AREA TOMORROW. HOWEVER...PRECISELY WHERE THAT PRECIP WILL BE FOCUSED IS DIFFICULT TO SAY GIVEN DIFFERING MODEL SOLUTIONS. THE 00Z NAM FORECASTS THIS AREA OF PRECIP TO TRACK ACROSS THE CENTRAL SF BAY AREA FROM MID MORNING TO EARLY AFTERNOON. THE 00Z GFS AND LATEST HRRR MODEL BOTH INDICATE THIS PRECIP WILL BE FOCUSED ACROSS EASTERN ALAMEDA AND SANTA CLARA COUNTIES AND SOUTH INTO SAN BENITO COUNTY. GIVEN MODEL DIFFERENCES...BELIEVE IT`S BEST NOT TO TRY TO PINPOINT AREAS OF HIGHEST PRECIP POTENTIAL AND INSTEAD CONTINUE TO DISTRIBUTE CHANCE POPS ACROSS OUR FORECAST AREA RATHER UNIFORMLY. THUNDERSTORMS ARE A POSSIBILITY ONCE AGAIN TOMORROW. HOWEVER...BECAUSE THE SHORTWAVE TROUGH WILL HAVE ROTATED OUT OF OUR AREA PRIOR TO THE BEST SURFACE HEATING IN THE AFTERNOON...THUNDERSTORM POTENTIAL WILL BE SOMEWHAT DIMINISHED. THE UPPER LOW IS FORECAST TO LIFT TO THE NORTHEAST AND INTO THE SOUTHERN GREAT BASIN BY SATURDAY. THE MODELS AGREE THAT MOISTURE WILL CONTINUE TO WRAP AROUND THE LOW AND ACROSS OUR AREA ON SATURDAY AND THAT INSTABILITY WILL REMAIN SUFFICIENT FOR SCATTERED SHOWERS TO CONTINUE. HOWEVER...THUNDERSTORM CHANCES WILL HAVE FADED CONSIDERABLY BY THEN. A FEW SHOWERS MAY LINGER INTO SUNDAY MORNING...BUT FOR THE MOST PART SUNDAY LOOKS TO BE A DRY DAY WITH TEMPERATURES NEAR AVERAGE. DRY WEATHER WILL THEN CONTINUE THROUGH THE MIDDLE PART OF NEXT WEEK AS AN UPPER RIDGE BUILDS NEAR THE WEST COAST. THIS RIDGE WILL ALSO MEAN A GRADUAL WARMING TREND FOR MUCH OF NEXT WEEK. LONGER RANGE MODELS HINT AT THE POSSIBILITY OF ANOTHER CUTOFF LOW IMPACTING OUR AREA BY THE FOLLOWING WEEKEND (MAY 14 AND 15). && .AVIATION...AS OF 10:30 PM PDT THURSDAY...UPPER LEVEL LOW WEST OF THE CENTRAL COAST MOVING TOWARDS SOUTHERN CALIFORNIA. ISOLATED SHOWERS ARE CONFINED TO THE HILLS THIS EVENING WHILE PATCHY LOW CLOUDS ARE ALONG THE COAST. MVFR EXPECTED TO SPREAD OVER THE MRY BAY AREA THIS EVENING AND INTO THE SFO BAY AREA LATER TONIGHT. AN UPPER LEVEL DISTURBANCE ROTATING AROUND THE LOW WILL BRING A CHANCE OF SHOWERS TO THE AREA FRIDAY MORNING. THESE SHOWERS WILL BE COMING FROM THE NORTHEAST. MVFR CIGS EXPECTED MOST OF THE DAY FRIDAY. CANNOT RULE OUT AN ISOLATED THUNDERSTORM FRIDAY AFTERNOON. VICINITY OF KSFO...MVFR CIGS AFTER 12Z CONTINUING THROUGH THE REST OF THE DAY. SCATTERED SHOWERS AFTER 16Z. MAINLY LIGHT SOUTHWEST WINDS. SFO BRIDGE APPROACH...SIMILAR AS KSFO. MONTEREY BAY TERMINALS...MVFR CIGS AFTER 08Z. A FEW SHOWERS POSSIBLE AFTER 17Z. && .MARINE...AS OF 10:30 PM PDT THURSDAY...LOW PRESSURE DEVELOPING OVER NEVADA WILL MODERATE NORTHERLY WINDS TO THE OUTER WATERS NORTH OF PT REYES AND LIGHT SOUTH WINDS ELSEWHERE THROUGH FRIDAY. AN UPPER LEVEL LOW OFF THE CENTRAL CALIFORNIA COAST WILL MOVE INTO SOUTHERN CALIFORNIA ON FRIDAY. THIS WILL BRING A SLIGHT CHANCE OF THUNDERSTORMS TONIGHT AND FRIDAY. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM && $$ PUBLIC FORECAST: DYKEMA AVIATION: W PI MARINE: DRP VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK AND TWITTER AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
912 PM PDT THU MAY 5 2016 .SYNOPSIS...AN UPPER LEVEL LOW OFF OF THE CENTRAL CALIFORNIA COAST WILL SHIFT INLAND OVER SOUTHERN CALIFORNIA ON FRIDAY AND RESULT IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH FRIDAY EVENING. SCATTERED SHOWERS WILL LIKELY LINGER INTO SATURDAY WITH DRY WEATHER EXPECTED TO RETURN TO MOST AREAS BY SUNDAY. DRY WEATHER IS THEN FORECAST THROUGH THE MIDDLE OF NEXT WEEK ALONG WITH A GRADUAL WARMING TREND. && .DISCUSSION...AS OF 9:10 PM PDT THURSDAY...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OCCURRED ACROSS PORTIONS OF OUR FORECAST AREA TODAY. THIS CONVECTIVE PRECIPITATION WAS TRIGGERED BY AN UPPER LOW THAT IS CURRENTLY CENTERED ABOUT 100 MILES SOUTHWEST OF MONTEREY. THE MOST SIGNIFICANT RAINFALL TO OCCUR FROM TODAY`S SHOWER ACTIVITY WAS AT PINNACLES NATIONAL PARK WHERE 0.33" WAS RECORDED. IN OTHER LOCATIONS WHERE RAIN FELL TODAY...AMOUNTS WERE MOSTLY LESS THAN A TENTH OF AN INCH. A LINE OF INTENSE SHOWERS AND THUNDERSTORMS DEVELOPED JUST TO THE EAST OF SANTA CLARA AND SAN BENITO COUNTIES LATE THIS AFTERNOON. BUT THIS CONVECTIVE ACTIVITY EITHER WEAKENED CONSIDERABLY OR DISSIPATED AS IT MOVED TO THE NORTHWEST TOWARDS THE SANTA CLARA AND HOLLISTER VALLEYS THIS EVENING. NOW THAT THE SUN HAS SET ALL ACTIVITY HAS DIMINISHED AND EXPECT ONLY ISOLATED SHOWERS OVERNIGHT. THE CUTOFF LOW IS FORECAST TO MOVE GRADUALLY TO THE SOUTHEAST OVERNIGHT AND THEN TURN TO THE EAST AND INLAND OVER SOUTHERN CA ON FRIDAY MORNING. MEANWHILE...A SHORTWAVE TROUGH ROTATING AROUND THE LOW IS FORECAST TO MOVE ACROSS OUR AREA ON FRIDAY MORNING AND EARLY FRIDAY AFTERNOON. THE MODELS ALL SHOW AN ORGANIZED AREA OF PRECIP WITH THIS SHORTWAVE...TRACKING FROM NORTHEAST TO SOUTHWEST ACROSS OUR AREA TOMORROW. HOWEVER...PRECISELY WHERE THAT PRECIP WILL BE FOCUSED IS DIFFICULT TO SAY GIVEN DIFFERING MODEL SOLUTIONS. THE 00Z NAM FORECASTS THIS AREA OF PRECIP TO TRACK ACROSS THE CENTRAL SF BAY AREA FROM MID MORNING TO EARLY AFTERNOON. THE 00Z GFS AND LATEST HRRR MODEL BOTH INDICATE THIS PRECIP WILL BE FOCUSED ACROSS EASTERN ALAMEDA AND SANTA CLARA COUNTIES AND SOUTH INTO SAN BENITO COUNTY. GIVEN MODEL DIFFERENCES...BELIEVE IT`S BEST NOT TO TRY TO PINPOINT AREAS OF HIGHEST PRECIP POTENTIAL AND INSTEAD CONTINUE TO DISTRIBUTE CHANCE POPS ACROSS OUR FORECAST AREA RATHER UNIFORMLY. THUNDERSTORMS ARE A POSSIBILITY ONCE AGAIN TOMORROW. HOWEVER...BECAUSE THE SHORTWAVE TROUGH WILL HAVE ROTATED OUT OF OUR AREA PRIOR TO THE BEST SURFACE HEATING IN THE AFTERNOON...THUNDERSTORM POTENTIAL WILL BE SOMEWHAT DIMINISHED. THE UPPER LOW IS FORECAST TO LIFT TO THE NORTHEAST AND INTO THE SOUTHERN GREAT BASIN BY SATURDAY. THE MODELS AGREE THAT MOISTURE WILL CONTINUE TO WRAP AROUND THE LOW AND ACROSS OUR AREA ON SATURDAY AND THAT INSTABILITY WILL REMAIN SUFFICIENT FOR SCATTERED SHOWERS TO CONTINUE. HOWEVER...THUNDERSTORM CHANCES WILL HAVE FADED CONSIDERABLY BY THEN. A FEW SHOWERS MAY LINGER INTO SUNDAY MORNING...BUT FOR THE MOST PART SUNDAY LOOKS TO BE A DRY DAY WITH TEMPERATURES NEAR AVERAGE. DRY WEATHER WILL THEN CONTINUE THROUGH THE MIDDLE PART OF NEXT WEEK AS AN UPPER RIDGE BUILDS NEAR THE WEST COAST. THIS RIDGE WILL ALSO MEAN A GRADUAL WARMING TREND FOR MUCH OF NEXT WEEK. LONGER RANGE MODELS HINT AT THE POSSIBILITY OF ANOTHER CUTOFF LOW IMPACTING OUR AREA BY THE FOLLOWING WEEKEND (MAY 14 AND 15). && .AVIATION...AS OF 4:30 PM PDT THURSDAY...UPPER LEVEL LOW WEST OF THE CENTRAL COAST AREA WITH SCATTERED SHOWERS ROTATING THROUGH THE AREA FROM SOUTH TO NORTH. CIGS HAVE REMAINED AT OR ABOVE 3000 FEET BUT MAY LOWER INTO MVFR RANGE TONIGHT AS LOW-LEVEL COOLING TAKES PLACE. THE LOW WILL MOVE SLOWLY INTO SOUTHERN CALIFORNIA TONIGHT AND FRIDAY WITH WRAP-AROUND SHOWERS CONTINUING OVER THE AREA. CANNOT RULE OUT A THUNDERSTORM DURING THE AFTERNOON HOURS. VICINITY OF KSFO...OCCASIONAL MVFR CIGS THROUGH 04Z. BECOMING PREDOMINATELY MVFR AFTER 04Z AS COOLING OF THE LOWER ATMOSPHERE TAKES PLACE. RADAR INDICATES NO SHOWER ACTIVITY IN THE VICINITY BUT SCATTERED SHOWERS MAY SPREAD INTO THE AREA FROM THE SOUTH TONIGHT AND FROM THE EAST TO SOUTHEAST FRIDAY. SOUTHWEST WINDS 10-15 KT. SFO BRIDGE APPROACH...SIMILAR AS KSFO. MONTEREY BAY TERMINALS...VFR WITH CIGS REMAINING ABOVE 3000 FEET. CIGS LOWERING TO MVFR RANGE AFTER 06Z. VCSH THROUGH THE PERIOD. && .MARINE...AS OF 4:30 PM PDT THURSDAY...A STORM SYSTEM OVER THE REGION WILL BRING MODERATE NORTHERLY WINDS TO THE OUTER WATERS NORTH OF PT REYES AND LIGHT SOUTH WINDS ELSEWHERE INTO TOMORROW. HAZARDOUS CONDITIONS FROM SQUARED SEAS WILL BE ALSO BE POSSIBLE IN THE NORTHERN OUTER WATERS. THIS STORM WILL PRODUCE SHOWERS AND POSSIBLY THUNDERSTORMS OVER THE COASTAL WATERS TODAY. && .MTR WATCHES/WARNINGS/ADVISORIES... .TNGT...SCA...PT ARENA TO PIGEON PT 10-60 NM && $$ PUBLIC FORECAST: DYKEMA AVIATION: W PI MARINE: DRP VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK AND TWITTER AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1141 PM CDT THU MAY 5 2016 ...AVIATION UPDATE... .SYNOPSIS... ISSUED AT 315 PM CDT THU MAY 5 2016 HIGH PRESSURE RIDGE OVER THE CWA PROVIDING FULL SUNSHINE...LIGHT WINDS AND PLEASANT SPRING TEMPERATURES. 2 PM READINGS WERE IN THE UPPER 50S TO LOWER 60S. WEAK CONVERGENCE IN THE MID LEVELS HAS CAUSED A BAND OF MID LEVEL CLOUDS MUCH OF THE DAY FROM EASTERN MN INTO CENTRAL IA AND NORTH CENTRAL MO. THIS HAS PRETTY MUCH STAYED JUST WEST OF THE DVN CWA AS THE CLOUDS DRIFT SOUTHWARD. THERE HAS EVEN BEEN A FEW LIGHT SHOWERS REACHING THE GROUND IN FAR WESTERN WI AND THE EAST METRO OF THE TWIN CITIES. THESE SHOWERS WERE OCCURRING IN THE STRONGER ZONE OF WARM AIR ADVECTION. ELSEWHERE...TEMPERATURES WERE IN THE UPPER 70S TO MID 80S IN THE GREAT PLAINS...WITH SOME LOWER 90S IN ND AND MANITOBA. RELATIVE HUMIDITY THERE WAS 15 PERCENT WITH SOUTHWEST WINDS GUSTING OVER 30 MPH. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 315 PM CDT THU MAY 5 2016 MUCH WARMER TEMPERATURES IN THE SHORT TERM. TONIGHT...HIGH PRESSURE RIDGE WILL BE PUSHING SOUTH OF THE AREA ALLOWING FOR WARMER TEMPERATURES AS WINDS BECOMING LIGHT SOUTHWEST. LOWS WILL BE ABOUT 10 DEGREES WARMER THAN LAST NIGHT...IN THE UPPER 40S. SCATTERED MID LEVEL CLOUDS SHOULD DEVELOP OVERNIGHT BUT EXPECTING ANY SHOWERS TO REMAIN IN WISCONSIN WHERE THE BETTER WARM AIR ADVECTION WILL EXIST. BELIEVE THE HRRR IS OVERDOING THE SHOWERS IN THE DVN CWA BUT CAN`T RULE OUT A COUPLE OF SPRINKLES. WON`T MENTION IN THE GRIDS BUT SOMETHING FOR LATER SHIFTS TO MONITOR. FRIDAY...WARM DAY WITH THE RETURN FLOW AROUND THE HIGH PRESSURE SYSTEM DROPPING INTO THE LOWER MS VALLEY. A WEST TO SOUTHWEST WIND...850 MB TEMPERATURES OF +15 TO 16C AND A DRY AIRMASS SHOULD SUPPORT LOWER 80S AT MOST LOCATIONS. IT IS POSSIBLE A FEW SPOTS MAY MANAGE TO SEE 85 DEGREES CONSIDERING WE SHOULD HAVE SUNNY SKIES. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 315 PM CDT THU MAY 5 2016 SATURDAY...EASTWARD PROGRESSION OF THE 500MB RIDGE AXIS WILL BE HALTED BY A SHORTWAVE TROUGH DIVING SOUTHEASTWARD THROUGH THE UPPER MIDWEST AND GREAT LAKES. SIGNIFICANT HEIGHT FALLS ASSOCIATED WITH THIS SYSTEM ARE FORECAST TO REMAIN OVER WISCONSIN AND MICHIGAN AND POINTS TO THE E/NE. AS A RESULT...LIFT OVER E IOWA/W ILLINOIS WILL BE WEAK AND PRIMARILY RESTRICTED TO LOW-LEVEL CONVERGENCE ALONG A SOUTHWARD MOVING COLD FRONT. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG AND SLIGHTLY AHEAD OF THE FRONT...POPS ARE IN THE 30-40 PERCENT RANGE WITH RAIN AMOUNTS LESS THAN A TENTH FOR MOST AREAS. THE FRONT IS FORECAST TO REACH THE SOUTHERN CWA BY THE MID TO LATE AFTN. THUNDERSTORM DETAILS...THE BEST CHANCES FOR A FEW STRONG STORMS IN THE DVN CWA ARE IN THE COUNTIES ALONG AND SOUTH OF HIGHWAY 34...TO THE WEST OF GALESBURG...WHERE MUCAPES MAY EXCEED 1500 J/KG AND 0-6 KM BULK SHEAR IS NEAR 45 KTS OR SLIGHTLY HIGHER. SUNDAY THROUGH TUESDAY...SATURDAY/S COLD FRONT WILL BECOME QUASI- STATIONARY SATURDAY NIGHT AND RETURN AS A WARM FRONT SUNDAY AND MONDAY AS IT IS FORCED BY A NEW AREA OF LOW PRESSURE FORMING IN THE WEST-CENTRAL PLAINS. SHOWER AND THUNDERSTORM CHANCES ARE HIGHEST FROM SUNDAY NIGHT INTO TUESDAY. GFS 850MB WV TRANSPORT IS MAXIMIZED ON MONDAY AND MONDAY NIGHT AS PWATS INCREASE TO 1.25 INCHES TO THE ESE OF A COHERENT 850MB LOW MOVING INTO E NEBRASKA. RAIN POTENTIAL...THE THREAT FOR WIDESPREAD HEAVY RAIN WITH THIS LOW PRESSURE SYSTEM HIGHLIGHTED IN THE CPC 3-7 DAY HAZARDOUS WEATHER OUTLOOK HAS NOW SHIFTED FURTHER TO THE EAST TO INCLUDE THE ENTIRE FORECAST AREA. WHILE PWATS ARE NOT FORECAST TO BECOME ANOMALOUSLY HIGH...REMAINING BELOW 1 STANDARD DEVIATION...THE SYSTEM IS A SLOW MOVER AND SHOWS A SOLID MOISTURE CONNECTION WITH THE WESTERN GULF OF MEXICO...VIA 850 WV TRANSPORT VECTORS. THE WPC 5-7 DAY QPF SUPPORTS CPC/S OUTLOOK...PAINTING A GENERAL 1 TO 3 INCHES ALONG WHERE THE WARM FRONT SETS UP AND THE 850MB LOW TRACKS...FROM EASTERN NEBRASKA THROUGH IOWA AND NORTHERN MISSOURI INTO ILLINOIS AND SOUTHERN WISCONSIN. THUNDERSTORM POTENTIAL...TOO EARLY TO FORECAST WITH MUCH DETAIL. HOWEVER...SOME STRONG OR SEVERE STORMS ARE POSSIBLE ON MONDAY OVER THE SOUTHWEST SECTION OF THE FORECAST AREA. WIDESPREAD CLOUDS AND THE THREAT FOR RAIN TRANSLATES INTO NO BIG WARM UPS WITH AVG HIGH TEMPS IN THE LOWER 70S. WEDNESDAY...SEASONAL TEMPS CONTINUE WITH SLIGHT CHANCES FOR SHOWERS OR AN ISOLATED STORM. UTTECH && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1140 PM CDT THU MAY 5 2016 HIGH PRESSURE WILL BRING A VERY CLEAR CALM AND VFR NIGHT TO THE REGION TONIGHT...FOLLOWED BY A VFR DAY OF CLEAR/HIGH CLOUDS FRIDAY. WINDS WILL BE LIGHT WEST TO NORTHWEST OVERNIGHT...FOLLOWED BY A TURN TO SOUTHWEST TO WEST FRIDAY AROUND 10-15 KTS THROUGH THE DAYTIME HOURS. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...HAASE SHORT TERM...HAASE LONG TERM...UTTECH AVIATION...ERVIN
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1200 AM CDT FRI MAY 6 2016 ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Friday) Issued at 347 PM CDT THU MAY 5 2016 Northwest flow aloft continues across central and eastern Kansas this afternoon as we are in between a trough in the eastern Pacific and another over the eastern U.S.. Surface high extended from Iowa across eastern Kansas and into north Texas. The surface high will move off slowly to the east through tonight with southerly return flow developing from west to east after midnight. Another night of clear skies are expected tonight with lows dropping down into the upper 40s to lower 50s. Heights rise on Friday along with increasing warm advection and we should mix up to 850 mb or so across the area. Expect highs to reach the lower 80s with a few readings in the mid 80s in central Kansas. Winds increase through the day with increasing pressure gradient. Should also mix down stronger winds aloft which will yield wind gusts around 27 mph in north central Kansas in the afternoon. .LONG TERM...(Friday Night through Thursday) Issued at 347 PM CDT THU MAY 5 2016 Friday Night through Sunday... Warm air advection pattern still ramps up Friday night but limited moisture and instability aloft and dry layers below should keep any precip limited to sprinkles at most. Frontal boundary still appears to sink into the area Saturday afternoon but moisture values still recovering and warm air aloft should make local thunderstorm development difficult but small chances still justified in northern areas in the afternoon. Have inched up high temps for central and southern areas Saturday given the overnight WAA but with some high cloud and uncertainty on boundary location confidence is not high on specifics. More organized thunderstorm development is expected to occur in northeast Colorado and western Nebraska Saturday afternoon which could translate east over ridge and along the elevated front make its way into the area per Corfidi vectors. Could see MCS type precip linger into Sunday morning but area could easily be in moderately unstable airmass in the afternoon still well downstream of the upper low. If the old front or an outflow remains in the area there will be some chance for thunderstorms in peak heating. Winds aloft should be increasing somewhat but there will be some potential for severe weather. Sunday Night through Thursday... Uncertainty remains high for evolution of thunderstorm activity Sunday evening. Model to model consistency remains low with the placement of the warm front. Current 12Z guidance would suggest the warm front would position along the KS/NE border. The next question is will surface-base convection occur along the warm front. 12Z ECMWF/GFS forecast soundings along the KS/NE border valid at 00Z Monday suggest very weak to perhaps a completely eroded EML. If this solution were to come to fruition, all modes of severe weather would become possible as moderate instability and sufficient low- level/deep-layer shear will be in place. Good agreement amongst the ECMWF and GFS with passage of an upper level shortwave trough Sunday night into Monday morning. This solution suggests convection along the dryline in central/southern KS should congeal into line of elevated convection late Sunday evening and progress eastward across the area. Severe weather would be possible across the area as MUCAPE of 1500-2000 J/KG and deep-layer shear near 40-50 knots would support large hail and damaging wind gusts. Zonal to perhaps northwest flow returns for the middle of week. Precipitation chances increase Wednesday afternoon into Thursday as an embedded trough within the northern stream sweeps across the central plains. && .AVIATION...(For the 06Z TAFS through 06Z Friday Night) Issued at 1151 PM CDT THU MAY 5 2016 VFR conditions through the TAF with light winds tonight, occasional gusts up to 20 kts Friday afternoon, and then decreased gusts after sunset. && .TOP Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...53 LONG TERM...Baerg/65 AVIATION...Barjenbruch
Area Forecast Discussion National Weather Service Dodge City KS 1200 AM CDT FRI MAY 6 2016 ...updated aviation... .SHORT TERM...(This evening through Friday) Issued at 142 PM CDT Thu May 5 2016 Temperatures were rising faster than the forecast T curve early this morning, and a change to the Experimental HRRR appears to have captures the temperature forecast a little better in the midday. It may be a couple of degrees overdone as it is warmer than all the other guidance/blends, however with it being early May now the warming can last later in the day. The forecast high was generally bumped about 3 degrees over the area. The surface high will continue to give way to gradual troughing over eastern Colorado and the extreme western counties overnight. Much more breezy conditions to marginally windy conditions can be expected Friday. .LONG TERM...(Friday night through Thursday) Issued at 142 PM CDT Thu May 5 2016 Continued focus exists on the weekend for severe weather potential. Saturday and Sunday present somewhat different pattern recognition setups with marginal shear on Saturday, increasing by Sunday as the upper jet advances into the central High Plains. CAPES appear moderate on Saturday, and a few hail and wind producing severe storms could develop near the dryline in this marginal shear environment. The ECMWF is the model that pushes the dryline almost out of our forecast area on Sunday afternoon before convection initiation, while the GFS was far more emphatic with convection occurring farther west. Many characteristics of the mesoscale are as of yet unknown, however thunderstorms are probable this weekend. The best chance for the most widespread severe and especially tornadic threat would be more likely farther north where the models are in agreement with placement of the warm front. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1200 AM CDT Fri May 6 2016 VFR expected through TAF pd. LLWS expected overnight and then again tomorrow overnight. Southerly winds will increase 20-30 kt beginning around 18Z as lee trough deepens. && .PRELIMINARY POINT TEMPS/POPS... DDC 54 86 59 84 / 0 0 10 30 GCK 54 88 57 83 / 0 10 10 30 EHA 51 85 55 82 / 0 10 10 20 LBL 53 87 57 85 / 0 0 10 20 HYS 52 87 60 82 / 0 10 10 50 P28 54 86 60 84 / 0 0 10 20 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Russell LONG TERM...Russell AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS JACKSON KY
405 AM EDT FRI MAY 6 2016 .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 405 AM EDT FRI MAY 6 2016 07Z SFC ANALYSIS SHOWS LOW PRESSURE OFF TO THE EAST OF THE APPALACHIANS. WHILE HIGH PRESSURE IS FOUND TO THE SOUTHWEST. A FEW LINGERING LIGHT SHOWERS ARE DRIFTING SOUTH THROUGH FAR EASTERN KENTUCKY FROM THAT EASTERN LOW. IN CONJUNCTION WITH THIS...LOW AND MID LEVEL CLOUDS ARE FOUND CLOSER TO THE VIRGINIA AND WEST VIRGINIA BORDER. IN THE CLEARING TO THE WEST OF THE BORDER AREAS...PATCHY FOG IS NOTED IN THE SOME OF THE OBSERVATIONS. TEMPERATURES ARE RUNNING IN THE LOW TO MID 40S ACROSS THE AREA WITH DEWPOINTS NOT FAR AWAY...WHILE WINDS ARE GENERALLY LIGHT FROM THE NORTHWEST. THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST. THEY ALL DEPICT A CONUS OMEGA BLOCK SHIFTING EAST AND OPENING UP DURING THE NEXT 48 HOURS. A DEEP CLOSED LOW DESCENDING THROUGH THE SOUTHERN APPALACHIANS THIS MORNING WILL PIVOT TO THE NORTHEAST BY EVENING BEFORE BEING PICKED UP BY THE NORTHERN STREAM FLOW AND DEPARTING OFF THE MID ATLANTIC COAST SATURDAY EVENING. IN ITS WAKE...RISING HEIGHTS AND RIDGING WILL SPREAD FROM THE SOUTHERN PLAINS AND ACROSS THE MISSISSIPPI VALLEY TOWARD KENTUCKY. HOWEVER...IN ASSOCIATION WITH A HUDSON BAY UPPER LOW DESCENDING INTO THE GREAT LAKES...A MINOR WAVE WILL SQUEEZE BY EASTERN KENTUCKY TO THE NORTH LATE SATURDAY. GIVEN THE MODEL AGREEMENT HAVE FOLLOWED A GENERAL BLEND WITH A STRONG LEAN TOWARD THE HRRR EARLY ON AND THE NAM12 THEREAFTER. SENSIBLE WEATHER WILL FEATURE A MILDER DAY THAN YESTERDAY AS SOME SUNSHINE RETURNS AND THE COLD AIR DEPARTS TO THE EAST. ISOLATED TO SCATTERED SHOWERS WILL BE FOUND OVER FAR EASTERN KENTUCKY THROUGH THE AFTERNOON. FOR TONIGHT...EXPECT A SMALL RIDGE TO VALLEY SPLIT TO SET UP AHEAD OF A DEVELOPING WARM FRONT WITH PATCHY VALLEY FOG AROUND...SIMILAR TO THIS MORNING. A FEW LIGHT SHOWERS CANNOT BE RULED OUT WITH THAT BOUNDARY THROUGH THE MORNING...ESPECIALLY EAST BY MIDDAY SATURDAY. A COLD FRONT WILL THEN SETTLE SOUTH TOWARD EASTERN KENTUCKY LATER SATURDAY. BETWEEN THESE FEATURES...OUR AREA WILL BE IN THE WARM SECTOR OF A QUICK MOVING SFC LOW AND AS A RESULT COULD SEE SOME CONVECTION DEVELOP WITH FAVORABLE PARAMETERS FOR STRONG TO SEVERE STORMS BUILDING DURING THE AFTERNOON AND INTO THE EVENING. SPECIFICALLY...CAPE WILL BE MODERATE WITH LOW LIS AND VEERING/INCREASING WINDS WITH HEIGHT. WILL HIGHLIGHT THIS FURTHER IN THE FORTHCOMING HWO WITH HAIL AND GUSTY WINDS THE MAIN THREAT. USED THE SHORTBLEND/SUPERBLEND AS A STARTING POINT FOR MOST ELEMENTS WITH SOME MINOR ADJUSTMENTS TO THE AFTERNOON DEWPOINTS AND SOME TERRAIN DIFFERENCES FOR TEMPERATURES TONIGHT. DID ADJUST POPS TO BE A BIT ABOVE THE POPULATION SCHEME...IN THE EAST THROUGH TODAY AND ALSO FOR THE STRONG/SEVERE STORM CONCERNS ON SATURDAY AFTERNOON. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 405 AM EDT FRI MAY 6 2016 THE EXTENDED PORTION OF THE FORECAST BEGINS SATURDAY NIGHT WITH AN ACTIVE PATTERN IN PLACE. UPPER CLOSED LOW OVER THE SOUTHEASTERN CANADA REGION WILL BE IN PLACE THROUGH THE WEEKEND AS IT SLOWLY SHIFTS EAST INTO THE COMING WEEK. THIS FEATURE CONTINUES TO SWING A FEW SHORTWAVES INTO THE LOWER GREAT LAKES REGION THROUGH THE START OF THE NEW WEEK. MEANWHILE...AS A WEAKENING RIDGE OVER THE SOUTHEAST CONTINUES TO WEAKEN AND SHIFT EAST AS WELL WITH ANOTHER UPPER LEVEL LOW OVER THE CENTRAL PLAINS. THIS FEATURE OPENS AND EJECTS EAST INTO THE OHIO VALLEY BY MID WEEK. FOLLOWING THIS...TOWARDS THE END OF THE EXTENDED PERIOD...THE PATTERN BECOMES MORE AMPLIFIED AS ANOTHER UPPER LOW MOVES INTO THE UPPER PLAINS WITH A WEAKENING RIDGE OVER THE OH VALLEY SHIFTING. OVERALL...BOTH THE GFS AND EURO HAVE A DECENT HANDLE ON THE UPPER LEVEL PATTERN THROUGH NEXT WEEK. THOUGH THE GFS IS A BIT MORE DRIER THAN THE EURO...THE BOTTOM LINE IS THAT THE EXTENDED SEEMS QUITE WET AND ACTIVE. THIS SOLUTION IS ALSO CONFIRMED BY THE ALL MODEL BLEND AS WELL KEEPING THE CHANCE OF PRECIP THROUGH JUST ABOUT EVERY DAY OF THE EXTENDED. NEAR THE SURFACE HEADING INTO SATURDAY NIGHT AND SUNDAY...A SURFACE LOW PRESSURE SYSTEM DEVELOPING UP OVER THE CENTRAL PLAINS SETS UP A WARM FRONT INTO THE MIDWEST AND A QUASI STATIONARY BOUNDARY INTO THE OH VALLEY. THIS BOUNDARY BECOMES A FOCUS FOR CONTINUED CONVECTION SATURDAY NIGHT AND SUNDAY. IN FACT...THE EURO MIGHT SUGGEST AN MCS SET UP FOR THIS TIME PERIOD. INSTABILITY AND SHEAR SEEM SUBSTANTIAL FOR ORGANIZED CONVECTION AT LEAST EARLY IN THE SATURDAY NIGHT PERIOD AND AGAIN SUNDAY AFTERNOON FOCUSING ON MAX HEATING. STRONG CAPPING HEADING INTO THE DAY MONDAY WOULD LIMIT CONVECTION A BIT MORE AS THE MENTIONED BOUNDARY LIFTS NORTH. STILL WILL KEEP LOW CHANCE POPS IN THE NORTH CLOSER TO THE BOUNDARY. TUESDAY...THE SYSTEM OUT WEST SHIFTS EAST WITH STRONG UPPER LEVEL SUPPORT. STRONG CONVECTION SEEMS TO DEVELOP AHEAD OF THE COLD FRONT TUESDAY AFTERNOON INTO TUESDAY NIGHT. THIS WILL KEEP LIKELY POPS IN THE FORECAST THROUGH WEDNESDAY AS GFS MODEL SOUNDINGS KEEP GOOD INSTABILITY IN PLACE TUESDAY AND WEDNESDAY AFTERNOON. IN FACT...THIS SYSTEM WILL BE FOLLOWED BY A DISTURBANCE TO MOVE INTO THE AREA ON THURSDAY. MODELS HIGHLIGHT AN ACTIVE EXTENDED FORECAST THROUGH NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 115 AM EDT FRI MAY 6 2016 THE WORST OF THE AVIATION CONDITIONS WILL BE THROUGH THE REST OF THE NIGHT AS SCATTERED SHOWERS DRIFT JUST WEST OF SOUTH THROUGH THE FAR EASTERN PARTS OF THE AREA. THESE LOCATIONS...PRIMARILY SJS...WILL SEE THE BEST SHOT AT MVFR CONDITIONS FOR BOTH VIS AND CIGS WITH ANY SHOWER. ELSEWHERE...PATCHY FOG MAY IMPACT A TAF SITE OR TWO WEST OF THE AREA OF SHOWERS...BUT FOR THE MOST PART VFR CONDITIONS WILL PREVAIL. THROUGH THE DAY FRIDAY AND INTO THE EVENING VFR WILL HOLD AS HIGH PRESSURE MAKES ITS INFLUENCE KNOWN. WINDS THROUGH THE PERIOD WILL BE GENERALLY BETWEEN 5 AND 10 KTS FROM THE NORTHWEST. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
135 AM EDT FRI MAY 6 2016 .UPDATE... ISSUED AT 135 AM EDT FRI MAY 6 2016 DID A QUICK UPDATE TO FINE TUNE THE GRIDS THROUGH DAYBREAK PER THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS. ALSO ADDED A TOUCH OF PATCHY FOG TO THE WX GRIDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 1007 PM EDT THU MAY 5 2016 RECENT RADAR TRENDS INDICATE THAT THE RAIN SHOWERS WILL CONTINUE TO EXPERIENCE OVERNIGHT WILL NOT SPREAD QUITE AS FAR WESTWARD...OR BE QUITE AS WIDESPREAD...AS PREVIOUSLY FORECAST. THEREFORE...THE HOURLY FORECAST GRIDS THROUGH 12Z FRIDAY HAVE BEEN UPDATED TO REFLECT THESE LATEST TRENDS. AN UPDATED ZONE FORECAST TEXT PRODUCT HAS BEEN ISSUED AS WELL. THE REST OF THE FORECAST IS IN GOOD SHAPE. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 325 PM EDT THU MAY 5 2016 WV SAT AND HRRR HAS SUGGESTED THAT THE UPPER LEVEL CLOSED LOW HAS PROGRESSED SOUTHEAST INTO WESTERN NC AND NW SC. OVERALL THE MESO MODELS AND MORE SYNOPTIC MODELS HAVE HAD A DECENT HANDLE ON THIS PROGRESSION. WE CONTINUE TO HAVE SOME SHOWERS THAT HAVE DEVELOPED ACROSS THE SOUTH AND SW PORTIONS OF THE CWA. THIS HAS BEEN DUE TO THE STEEPER LOW LEVEL LAPSE RATES...AS WE HAVE SEEN BREAKS IN THE CLOUDS. THESE LAPSE RATES ARE COMBINING WITH THE ALREADY REASONABLY STEEP MID LEVEL LAPSE RATES. OVERALL COVERAGE HAS BEEN SCATTERED WITH BETTER COVERAGE TO THE SOUTH AND EAST. RIGHT NOW MODELS DO WANT TO BRING ADDITIONAL SHOWERS IN THE FAR EAST THIS EVENING AND TONIGHT...HOWEVER BIGGEST QUESTION WOULD BE HOW MUCH COVERAGE DO WE SEE. RIGHT NOW OPTED TO LOWER POPS GIVEN SOME OF THE UNCERTAINTY. THIS UNCERTAINTY COMES WHEN LOOKING UPSTREAM RADAR COVERAGE IS QUITE LOW COMPARED TO WHAT MAY HAVE BEEN PREVIOUSLY THOUGHT AND CAMS ARE NOT HITTING IT TOO HARD EITHER. THE OTHER QUESTION WOULD BE HOW MUCH CLOUD COVER DO WE SEE TONIGHT...RIGHT NOW KEEP CLOUD COVER HIGHER IN THE EAST GIVEN THE BETTER SHOWER COVERAGE. ALSO COULD HAVE IMPLICATIONS ON TEMPS AND FOG POTENTIAL. RIGHT NOW WILL ADD SOME PATCHY DEEPER VALLEY FOG AND JUST MINOR TEMP SPLIT GIVEN THE CLOUD UNCERTAINTY. THIS UPPER LOW IS FAIRLY SLOW TO MOVE EAST...AS A OMEGA BLOCK PATTERN SETS UP ACROSS THE CENTRAL PART OF THE CONUS. THEREFORE SURFACE HIGH PRESSURE WILL BE SLOW TO BUILD NORTHEAST FROM THE GULF. THAT SAID THERE WAS A NEED FOR SHOWERS IN THE FAR EAST AND SOUTHEAST FOR FRIDAY GIVEN THE SLOW PROGRESS OF VERTICALLY STACKED LOW AND CONTINUED PVA/SHORTWAVES DIVING SOUTH. NOW FRIDAY NIGHT HEIGHTS WILL CONTINUE TO RISE AS UPPER LOW/OMEGA BLOCK BREAK DOWN AND PROGRESS EAST. THERE IS A WEAK SURFACE TROUGH OR WAVE MAY BRING SOME SLIGHT CHANCE SHOWERS TO THE FAR NORTH OVERNIGHT. OTHERWISE MOST SPOTS SHOULD DRY OUT AT THIS POINT. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 353 PM EDT THU MAY 5 2016 MODELS ARE IN REASONABLY GOOD AGREEMENT WITH AN OMEGA BLOCK PATTERN DEAMPLIFYING OVER THE WEEKEND AND EVOLVING TO MORE OR LESS A SPLIT FLOW PATTERN NEXT WEEK. THE CURRENT UPPER LEVEL SYSTEM MEANDERING OF THE APPALACHIANS AND THE SOUTHEAST IS EXPECTED TO SHIFT OFF THE EASTERN SEABOARD. AT THE SAME TIME...AN UPPER LEVEL LOW WILL MOVE FROM THE HUDSON AND JAMES BAY REGION INTO ONTARIO AND QUEBEC AND THEN INTO THE CANADIAN OVER THE WEEKEND AND INTO EARLY NEXT WEEK. A SHORTWAVE TROUGH IS EXPECTED TO MOVE THROUGH THE GREAT LAKES REGION EARLY IN THE PERIOD AND INTO THE NORTHEASTERN CONUS BY THE END OF THE WEEKEND. THIS WILL SEND A COLD FRONT INTO THE OHIO VALLEY AND APPALACHIAN REGION FROM LATE SATURDAY INTO SATURDAY NIGHT...WITH THE BOUNDARY STALLING OUT LATE IN THE WEEKEND ACROSS THE OHIO OR TENNESSEE VALLEY. THE MODEL CONSENSUS IS FOR A SMALL CHANCE OF CONVECTION ON ISENTROPIC LIFT EARLY IN THE PERIOD ON SATURDAY. A LULL IN ACTIVITY IS POSSIBLE FROM MIDDAY INTO THE AFTERNOON ON SATURDAY...WITH MORE ORGANIZED CONVECTION LIKELY SATURDAY EVENING INTO SATURDAY NIGHT. CHANCES FOR CONVECTION APPEAR TO LESSEN ON SUNDAY AS THE SHORTWAVE TROUGH DEPARTS TO THE EAST AND NORTHEAST. AN AREA OF SFC LOW PRESSURE MEANWHILE WILL BEGIN TO DEVELOP OVER THE WEEKEND IN THE LEE OF THE ROCKIES AHEAD OF THE SECOND UPPER LEVEL LOW MEANDERING FROM THE SOUTHWESTERN CONUS INTO THE ROCKIES OVER THE WEEKEND AND EVENTUALLY EJECTING INTO THE PLAINS. IN RESPONSE TO THE DEVELOPING LOW AND HEIGHT RISES OVER THE SOUTHEASTERN CONUS...THE STATIONARY FRONT SHOULD RETURN NORTH AS A WARM FRONT MONDAY INTO MONDAY NIGHT. EVEN AS THE REGION GETS INTO THE WARM SECTOR CONVECTION CANNOT BE RULED OUT AT ANY POINT ON MONDAY. THE SFC LOW PRESSURE SYSTEM SHOULD GRADUALLY TRACK FROM THE PLAINS TOWARD THE GREAT LAKES REGION AT MIDWEEK AND THEN EVENTUALLY INTO THE NORTHEASTERN CONUS. MODEL AGREEMENT FROM RUN TO RUN AND MODEL TO MODEL IN THESE DETAILS DIMINISHES GREATLY BY TUESDAY AND TUESDAY NIGHT AND ALSO CONFIDENCE IN ANY DETAILS. HOWEVER...THE OVERALL MODEL BLEND AND CONSENSUS APPEARS TO BE FOR ANOTHER PEAK IN CONVECTION CHANCES FROM LATE MONDAY NIGHT OR TUESDAY INTO THE DAY ON WEDNESDAY AS SEVERAL SHORTWAVES SHOULD MOVE THROUGH THE OHIO VALLEY AND GREAT LAKES REGION. LOCALLY HEAVY RAIN COULD BECOME A CONCERN IN LOCATIONS THAT EXPERIENCE MULTIPLE ROUNDS OF CONVECTION. TEMPERATURES SHOULD AVERAGE ABOVE NORMAL IN THE WARM SECTOR TO START THE PERIOD...ALTHOUGH TEMPERATURES SHOULD BE SUPPRESSED ON SUNDAY AND SUNDAY NIGHT WITH THE FRONT ACROSS THE AREA AND ABUNDANT CLOUD COVER ANTICIPATED. THEREAFTER...TEMPERATURES SHOULD AVERAGE A BIT ABOVE NORMAL THROUGH THE REST OF THE PERIOD...WITH HIGHS IN THE MID 70S TO AROUND 80 AND LOWS IN THE UPPER 50S TO AROUND 60. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 115 AM EDT FRI MAY 6 2016 THE WORST OF THE AVIATION CONDITIONS WILL BE THROUGH THE REST OF THE NIGHT AS SCATTERED SHOWERS DRIFT JUST WEST OF SOUTH THROUGH THE FAR EASTERN PARTS OF THE AREA. THESE LOCATIONS...PRIMARILY SJS...WILL SEE THE BEST SHOT AT MVFR CONDITIONS FOR BOTH VIS AND CIGS WITH ANY SHOWER. ELSEWHERE...PATCHY FOG MAY IMPACT A TAF SITE OR TWO WEST OF THE AREA OF SHOWERS...BUT FOR THE MOST PART VFR CONDITIONS WILL PREVAIL. THROUGH THE DAY FRIDAY AND INTO THE EVENING VFR WILL HOLD AS HIGH PRESSURE MAKES ITS INFLUENCE KNOWN. WINDS THROUGH THE PERIOD WILL BE GENERALLY BETWEEN 5 AND 10 KTS FROM THE NORTHWEST. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...DJ LONG TERM...JP AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
249 AM EDT FRI MAY 6 2016 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 354 PM EDT THU MAY 5 2016 12Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW A NNW FLOW ALOFT DOMINATING THE WRN GREAT LKS BTWN DEEP UPR TROF OVER THE E AND AN UPR RDG IN CENTRAL NAMERICA. A SFC HI PRES RDG STRETCHING FM THE UPR MIDWEST INTO WRN QUEBEC AS WELL AS DRY AIRMASS SHOWN ON THE 12Z GRB RAOB IS BRINGING A MOSUNNY DAY TO UPR MI...BUT MORE MAINLY MID/HI CLDS RELATED TO WAA IN THE SW FLOW ON THE BACK SIDE OF THE RDG ARE PRESENT FM WRN LK SUP INTO CENTRAL ONTARIO. THERE WERE SOME SHOWERS UNDER THESE CLDS OVER MN WHERE MID LVL LAPSE RATES HAVE BEEN STEEPER...BUT ABSENCE OF FORCING OTHER THAN WAA AND RELATIVELY DRY NATURE OF THE AIRMASS ARE LIMITING THE COVERAGE OF THIS PCPN...WITH A DIMINISHING TREND IN RECENT HRS. TNGT...AS SFC HI PRES RDG CONTINUES TO SLIDE SEWD...SW FLOW/WAA ARE PROGGED TO DOMINATE THE CWA. EXPECT SOME MID/HI CLDS RELATED TO THIS WAA TO PASS OVER THE CWA MAINLY THRU 06Z BEFORE SUBSIDENCE RELATED TO SHARPENING H7 RDG AXIS DRIES UP THESE CLDS. CONSIDERED ADDING SOME ISOLD SHOWERS LATE THIS AFTN/THIS EVNG OVER THE FAR W WHERE NAM SHOWS POCKET OF H7-5 LAPSE RATES ARND 8C/KM AND SOME OF THE HIER RES MODELS GENERATE SPOTTY QPF...BUT LATEST RADAR TRENDS SUG THE AIRMASS IS SO DRY IN A RELATIVE SENSE THAT THE DRY FCST GUIDANCE IS ON THE RIGHT TRACK. COMBINATION OF THE WAA CLDS AND LLVL WARMING RELATED TO STEADY SW FLOW WL HOLD MIN TEMPS UP MUCH HIER THAN THIS MRNG. IN FACT...READINGS MAY NOT FALL BLO 50 OVER THE FAR W FM IRONWOOD TO ONTONAGON WHERE THE SW FLOW WL DOWNSLOPE. FRI...UPR MI WL BE IN THE WARM SECTOR BTWN DEPARTING SFC HI PRES RDG TO THE SE AND SFC LO PRES TRACKING ACROSS NW ONTARIO AHEAD OF SHRTWV MOVING OVER WRN RDG AND INTO FAR NW ONTARIO LATE IN THE DAY. WITH H85 TEMPS FCST AS HI AS 18C AND A GOOD DEAL OF SUNSHINE WITHIN LINGERING DRY AIRMASS...TEMPS AWAY FM THE MODERATING INFLUENCE OF MAINLY LK MI OVER THE W HALF WL RISE WELL INTO THE 80S AND PERHAPS ARPCH 90 AT A FEW LOCATIONS. WITH DAYTIME MIXING CAUSING SFC DEWPTS TO DROP AT LEAST CLOSE TO 40 IN THE AFTN...EXPECT MIN RH TO DIP NEAR 20 PCT AT A FEW PLACES. ALTHOUGH STRONG WINDS ARE NOT EXPECTED WITH GUSTS UP TO ARND 20 MPH...FIRE WX CONCERNS WL BE ELEVATED. WINDS WL BE A BIT STRONGER OVER THE E...BUT MODERATION OFF LK MI WL LIMIT FIRE WX CONCERNS THERE. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 249 AM EDT FRI MAY 6 2016 UPPER AIR PATTERN CONSISTS OF A CLOSED 500 MB LOW OVER THE ROCKIES AND ANOTHER OVER THE ERN U.S. AND ANOTHER NEAR HUDSON BAY IN A RATHER BLOCKY PATTERN 12Z SAT. THE HUDSON BAY CLOSED LOW HAS A TROUGH THAT IS MOVING THROUGH THE UPPER GREAT LAKES ON SAT. THIS TROUGH THEN MOVES INTO NEW ENGLAND ON SUN. THE CLOSED 500 MB LOW MOVES INTO THE CENTRAL PLAINS 12Z MON. IN SPITE OF THE UPPER LEVELS...LOOKS PRETTY DRY OVERALL AND QUIET. IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW OVER THE CENTRAL PLAINS 12Z MON AND TROUGHING ACROSS SW CANADA WITH A RIDGE OVER THE NORTHERN PLAINS AND INTO THE CANADIAN PRAIRIES AND A TROUGH IN ERN CANADA. UPPER PATTERN DOES NOT CHANGE MUCH FOR 12Z TUE. BLOCKY PATTERN CONTINUES FOR 12Z WED WITH OMEGA BLOCK OVER THE UPPER GREAT LAKES WITH TROUGHING IN THE ROCKIES AND A TROUGH OVER THE UPPER GREAT LAKES. TROUGHING MOVES INTO THE NORTHERN PLAINS 12Z THU WITH RIDGING OVER THE UPPER GREAT LAKES. TEMPERATURES LOOK TO BE NEAR NORMAL FOR THIS FORECAST PERIOD AND GENERALLY LOOKS QUIET AS POPS LOOK TO STAY MOSTLY SOUTH OF THE AREA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 135 AM EDT FRI MAY 6 2016 VFR CONDITIONS WILL PREVAIL THRU THIS AFTN AT KIWD/KCMX/KSAW AS A DRY AIR MASS WILL LINGER DESPITE HIGH PRES EXITING AND A COLD FRONT APPROACHING. MARGINAL LLWS IS EXPECTED THRU THE REMAINDER OF TONIGHT AT KIWD/KSAW WITH STRONGER WINDS NOTED ABOVE NOCTURNAL INVERSION PER KMQT/KDLH VAD WIND PROFILES AND MODEL FCSTS. COLD FRONT WILL SWEEP ACROSS THE AREA LATE THIS EVENING AND OVERNIGHT...BRINGING A WSHFT TO THE N AND PERHAPS A FEW SHRA. COVERAGE SHOULD BE SOMEWHAT LIMITED...SO MOSTLY A VCSH WAS UTILIZED IN FCST. MIGHT BE A BRIEF PERIOD OF MVFR CONDITIONS IF A SHRA DOES AFFECT ANY OF THE TERMINALS. A BRIEF PERIOD OF LLWS WILL BE POSSIBLE AT KIWD AND KCMX AT THE END OF THE PERIOD AS LOW-LEVEL MARINE AIR BEHIND THE FRONT STABILIZES THE NEAR SFC LAYER. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 354 PM EDT THU MAY 5 2016 SSW WINDS UP TO 20 KTS AHEAD OF AN APPROACHING COLD FRONT WILL SHIFT TO THE N AT 20-25 KTS FRI NIGHT INTO SAT FOLLOWING THE PASSAGE OF THIS BOUNDARY. AS HI PRES BUILDS OVER THE AREA BY LATE IN THE WEEKEND...THESE WINDS WILL DIMINISH UNDER 15-20 KTS INTO EARLY NEXT WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...07 AVIATION...ROLFSON/KLUBER MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 AM EDT FRI MAY 6 2016 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 354 PM EDT THU MAY 5 2016 12Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW A NNW FLOW ALOFT DOMINATING THE WRN GREAT LKS BTWN DEEP UPR TROF OVER THE E AND AN UPR RDG IN CENTRAL NAMERICA. A SFC HI PRES RDG STRETCHING FM THE UPR MIDWEST INTO WRN QUEBEC AS WELL AS DRY AIRMASS SHOWN ON THE 12Z GRB RAOB IS BRINGING A MOSUNNY DAY TO UPR MI...BUT MORE MAINLY MID/HI CLDS RELATED TO WAA IN THE SW FLOW ON THE BACK SIDE OF THE RDG ARE PRESENT FM WRN LK SUP INTO CENTRAL ONTARIO. THERE WERE SOME SHOWERS UNDER THESE CLDS OVER MN WHERE MID LVL LAPSE RATES HAVE BEEN STEEPER...BUT ABSENCE OF FORCING OTHER THAN WAA AND RELATIVELY DRY NATURE OF THE AIRMASS ARE LIMITING THE COVERAGE OF THIS PCPN...WITH A DIMINISHING TREND IN RECENT HRS. TNGT...AS SFC HI PRES RDG CONTINUES TO SLIDE SEWD...SW FLOW/WAA ARE PROGGED TO DOMINATE THE CWA. EXPECT SOME MID/HI CLDS RELATED TO THIS WAA TO PASS OVER THE CWA MAINLY THRU 06Z BEFORE SUBSIDENCE RELATED TO SHARPENING H7 RDG AXIS DRIES UP THESE CLDS. CONSIDERED ADDING SOME ISOLD SHOWERS LATE THIS AFTN/THIS EVNG OVER THE FAR W WHERE NAM SHOWS POCKET OF H7-5 LAPSE RATES ARND 8C/KM AND SOME OF THE HIER RES MODELS GENERATE SPOTTY QPF...BUT LATEST RADAR TRENDS SUG THE AIRMASS IS SO DRY IN A RELATIVE SENSE THAT THE DRY FCST GUIDANCE IS ON THE RIGHT TRACK. COMBINATION OF THE WAA CLDS AND LLVL WARMING RELATED TO STEADY SW FLOW WL HOLD MIN TEMPS UP MUCH HIER THAN THIS MRNG. IN FACT...READINGS MAY NOT FALL BLO 50 OVER THE FAR W FM IRONWOOD TO ONTONAGON WHERE THE SW FLOW WL DOWNSLOPE. FRI...UPR MI WL BE IN THE WARM SECTOR BTWN DEPARTING SFC HI PRES RDG TO THE SE AND SFC LO PRES TRACKING ACROSS NW ONTARIO AHEAD OF SHRTWV MOVING OVER WRN RDG AND INTO FAR NW ONTARIO LATE IN THE DAY. WITH H85 TEMPS FCST AS HI AS 18C AND A GOOD DEAL OF SUNSHINE WITHIN LINGERING DRY AIRMASS...TEMPS AWAY FM THE MODERATING INFLUENCE OF MAINLY LK MI OVER THE W HALF WL RISE WELL INTO THE 80S AND PERHAPS ARPCH 90 AT A FEW LOCATIONS. WITH DAYTIME MIXING CAUSING SFC DEWPTS TO DROP AT LEAST CLOSE TO 40 IN THE AFTN...EXPECT MIN RH TO DIP NEAR 20 PCT AT A FEW PLACES. ALTHOUGH STRONG WINDS ARE NOT EXPECTED WITH GUSTS UP TO ARND 20 MPH...FIRE WX CONCERNS WL BE ELEVATED. WINDS WL BE A BIT STRONGER OVER THE E...BUT MODERATION OFF LK MI WL LIMIT FIRE WX CONCERNS THERE. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 319 PM EDT THU MAY 5 2016 LONG TERM STARTS AT 00Z SAT WITH THE UPPER RIDGE AND WARM AIRMASS OVER THE REGION. 850MB TEMPS WILL BE AROUND 17C AT 00Z...BUT WILL DROP TO 1-2C BY 18Z SAT BEHIND A SHORTWAVE TROUGH AND COLD FRONT. MODELS CONTINUE TO PAINT UP TO 0.20 INCHES OF QPF OVER MUCH OF THE AREA FRI NIGHT...BETWEEN 00Z AND 12Z SAT...BUT SOME AREAS MAY NOT EVEN SEE 0.10 INCHES. EXPECT THUNDERSTORMS AS ELEVATED INSTABILITY (CAPE UP TO 750 J/KG)...BUT NO SEVERE THUNDERSTORMS DUE TO WEAK SHEAR (0-6KM BULK SHEAR AROUND 20KTS). DRY AIR MOVES BACK IN ON SAT WITH SUNNY SKIES AND MIN RH VALUES IN THE MID 20S OVER THE INTERIOR W AROUND AROUND 40 PERCENT INTERIOR E. WINDS WILL BE LIGHT OVER THE W AND WILL GUST UP TO 25 MPH OVER THE E. IT WILL BE COOLER WITH HIGHS IN THE 50S NEAR LAKE SUPERIOR AND E AND AROUND 60 INTERIOR W. CERTAINLY NOT A CRITICAL FIRE WEATHER DAY BUT THE DRY AIR WILL PROBABLY NEGATE ANY MOISTURE WE GET FRI NIGHT. CAN NOT COMPLETELY RULE OUT A FEW LIGHT SHOWERS OVER NORTHERN LAKE SUPERIOR AND POSSIBLY THE KEWEENAW AND ERN UPPER MI SAT EVENING INTO SAT NIGHT AS ANOTHER SHORTWAVE PASSES N OF THE AREA...BUT THINK POTENTIAL IS LOW ENOUGH TO LEAVE OUT OF THE FORECAST FOR LAND AREAS. SUN WILL SEE SIMILAR TEMPS/RH/CLOUDS TO SAT...BUT WITH LOWER WINDS. MON AND TUE HAD APPEARED WET FROM EARLIER MODEL RUNS...BUT THOSE MODELS HAVE TRENDED DRIER. NOW ONLY THE 00Z/05 ECMWF SHOWS PRECIP OVER THE CWA...EXCEPT THE GLOBAL GEM WHICH HAS PRECIP BRUSHING SRN MENOMINEE COUNTY. WILL ACCORDINGLY START A DECREASING TREND FOR THE POP FORECAST FOR MON THROUGH TUE. NO PRECIP EXPECTED TUE NIGHT THROUGH THU. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 135 AM EDT FRI MAY 6 2016 VFR CONDITIONS WILL PREVAIL THRU THIS AFTN AT KIWD/KCMX/KSAW AS A DRY AIR MASS WILL LINGER DESPITE HIGH PRES EXITING AND A COLD FRONT APPROACHING. MARGINAL LLWS IS EXPECTED THRU THE REMAINDER OF TONIGHT AT KIWD/KSAW WITH STRONGER WINDS NOTED ABOVE NOCTURNAL INVERSION PER KMQT/KDLH VAD WIND PROFILES AND MODEL FCSTS. COLD FRONT WILL SWEEP ACROSS THE AREA LATE THIS EVENING AND OVERNIGHT...BRINGING A WSHFT TO THE N AND PERHAPS A FEW SHRA. COVERAGE SHOULD BE SOMEWHAT LIMITED...SO MOSTLY A VCSH WAS UTILIZED IN FCST. MIGHT BE A BRIEF PERIOD OF MVFR CONDITIONS IF A SHRA DOES AFFECT ANY OF THE TERMINALS. A BRIEF PERIOD OF LLWS WILL BE POSSIBLE AT KIWD AND KCMX AT THE END OF THE PERIOD AS LOW-LEVEL MARINE AIR BEHIND THE FRONT STABILIZES THE NEAR SFC LAYER. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 354 PM EDT THU MAY 5 2016 SSW WINDS UP TO 20 KTS AHEAD OF AN APPROACHING COLD FRONT WILL SHIFT TO THE N AT 20-25 KTS FRI NIGHT INTO SAT FOLLOWING THE PASSAGE OF THIS BOUNDARY. AS HI PRES BUILDS OVER THE AREA BY LATE IN THE WEEKEND...THESE WINDS WILL DIMINISH UNDER 15-20 KTS INTO EARLY NEXT WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...TITUS AVIATION...ROLFSON/KLUBER MARINE...KC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1238 AM CDT FRI MAY 6 2016 .UPDATE... ISSUED AT 1237 AM CDT FRI MAY 6 2016 MAIN CONCERN THIS UPDATE IS ARRIVAL OF THE COLD FRONT JUST ENTERING NORTHWESTERN NORTH DAKOTA. LOOKING LIKE WINDS BECOME NORTHWESTERLY...BUT DO NOT BEGIN INCREASING FOR A FEW HOURS BEHIND THE FRONTAL PASSAGE. STILL SOME AREAS IN SASKATCHEWAN WITH REDUCED VISIBILITY - LIKELY DUE TO SMOKE FROM LARGE FIRES IN NORTHERN ALBERTA/SASKATCHEWAN. SWIFT CURRENT HAD BEEN REPORTING VISIBILITIES OF 2-3 MILES BUT NOT SEEING OTHER SURROUNDING STATIONS WITH VISIBILITY REDUCTIONS. WILL BE MONITORING FOR FUTURE UPDATES. OTHERWISE BLENDED CURRENT OBSERVATIONS WITH TEMPERATURE TRENDS AND NO BIG CHANGES FOR THE OVERNIGHT HOURS. UPDATE ISSUED AT 943 PM CDT THU MAY 5 2016 MOST OF THE CUMULUS AND ISOLATED...HIGH-BASED SHOWERS /AND A LONE STORM THAT OCCURRED IN WILLIAMS COUNTY EARLIER/ ARE DIMINISHING WITH THE ONSET OF NOCTURNAL COOLING AND STABILIZATION. THAT IS IN LINE WITH OUR LATE AFTERNOON FORECAST UPDATE. THE MAIN QUESTION GOING FORWARD WILL BE WHAT /IF ANY/ SHOWER POTENTIAL EXISTS OVER- NIGHT. RECENT OPERATIONAL HRRR SIMULATIONS CONTINUE TO BE TOO AGGRESSIVE WITH CONVECTIVE DEVELOPMENT COMPARED TO REALITY...AND THE 18 UTC GFS AND 00 UTC NAM ARE AT ODDS OVER SHOWER POTENTIAL. THAT PROVIDED LOW ENOUGH CONFIDENCE FOR US TO KEEP A DRY FORECAST GOING OVERNIGHT...THOUGH THAT WILL NEED TO BE RE-EVALUATED LATER. THE ONE CHANGE WE DID MAKE WITH THIS UPDATE WAS TO INCREASE LOWS BY 2-4 F IN MOST AREAS BASED ON MID-EVENING TEMPERATURE TRENDS. FINALLY...ONE OTHER ISSUE THAT WE WILL NEED TO CONTEND WITH FOR LATER FORECAST RELEASES IS HOW THICK SMOKE FROM CANADIAN FIRES MAY BE FRIDAY. OBSERVATIONS IN SASKATCHEWAN HAVE SHOWN VISIBILITIES AS LOW AS 4SM FOR SEVERAL HOURS BEHIND THE COLD FRONT THAT WILL CROSS THE AREA. THUS...IT/S POSSIBLE THICKER LOW-LEVEL SMOKE MAY IMPACT PARTS OF WESTERN AND CENTRAL ND LATE TONIGHT AND FRIDAY. AT THE VERY LEAST IT SEEMS REASONABLE TO BELIEVE THE SMOKE WILL BE SENSIBLE VIA SMELL FRIDAY. UPDATE ISSUED AT 755 PM CDT THU MAY 5 2016 WE WILL LET THE RED FLAG WARNING EXPIRE AS SCHEDULED AT 8 PM CDT /01 UTC/...AS WINDS IN EAST CENTRAL ND HAVE DIMINISHED TO AROUND 10 MPH. HUMIDITIES ARE AT OR ABOVE 20 PERCENT AS OF 0050 UTC AND THEY WILL CONTINUE A SLOW RISE WITH THE ONSET OF DIURNAL COOLING. UPDATE ISSUED AT 551 PM CDT THU MAY 5 2016 WE HAVE ADDED A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM TO THE FORECAST THROUGH MID EVENING IN NORTHWEST ND. A HIGH-BASED SHOWER DEVELOPED NORTHWEST OF WILLISTON NEAR 2230 UTC...AND EVEN THOUGH THE ENTLN TOTAL LIGHTNING PLOT HAS NOT YET SHOWN ANY IN-CLOUD OR CLOUD-TO-GROUND STRIKES...THE STEEP LAPSE RATES AND WEAK MLCAPE /UP TO 250 J/KG PER THE SPC MESOANALYSIS/ IN THAT AREA SUGGEST A RUMBLE OR TWO OF THUNDER IS POSSIBLE. VISIBLE SATELLITE IMAGERY THROUGH 2245 UTC SHOWS CUMULUS ALL ALONG A WEAK SURFACE PRESSURE TROUGH EXTENDING FROM SOUTHEAST SASKATCHEWAN INTO EASTERN MT SO IT IS PLAUSIBLE MORE THAN JUST THAT INITIAL SHOWER MAY FORM. THAT BEING SAID...RECENT HRRR RUNS ARE LIKELY OVERDONE WITH EXPECTED DEVELOPMENT BASED ON THAT MODEL/S RECENT AND LONGER-TERM BIASES. OTHERWISE...WE ARE CONTINUING THE RED FLAG WARNING IN EAST CENTRAL ND FOR NOW GIVEN LATE-AFTERNOON OBSERVATIONS AND ONGOING FIRES. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 235 PM CDT THU MAY 5 2016 THE MAIN IMPACTS IN THE SHORT TERM ARE CRITICAL FIRE CONDITIONS TODAY AND A COLD FRONT TOMORROW. AN UPPER LEVEL RIDGE...COMBINED WITH A SURFACE TROUGH AND SOUTHWESTERLY MIXING WINDS...HAVE ALLOWED TEMPERATURES THIS AFTERNOON TO RISE RAPIDLY INTO THE 80S AND LOW 90S. THESE WARM TEMPERATURES HAVE FURTHER EXACERBATED DRY BOUNDARY LAYER CONDITIONS. WITH VERY DRY AIR MIXING DOWN RELATIVE HUMIDITY VALUES HAVE PLUMMETED INTO THE TEENS AND LOW 20S. WIND SPEEDS HAVE BEEN A BIT BREEZY ACROSS THE JAMES VALLEY. THIS IS WHAT PROMPTED THE ISSUANCE OF THE RED FLAG WARNING. WIND SPEEDS AROUND 20 MPH...COMBINED WITH HUMIDITY 20 PERCENT OR LESS AND DRY FUELS IS PRODUCING CRITICAL FIRE CONDITIONS ACROSS THE JAMES VALLEY. A COLD FRONT WILL SWEEP THROUGH TONIGHT INTO FRIDAY MORNING. WINDS WILL SHIFT OUT OF THE NORTH BETWEEN 20 AND 30 MPH. TOMORROW AFTERNOON MINIMUM RELATIVE HUMIDITY AROUND 20 PERCENT IS EXPECTED IN NORTHWEST AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA BY LATE AFTERNOON. HOWEVER...BY THIS TIME THE STRONGEST WINDS SHOULD HAVE PASSED TO THE SOUTH. THEREFORE...THESE AREAS MAY ESCAPE CRITICAL FIRE CONDITIONS. MODELS CONTINUE TO INDICATE A MAINLY DRY FRONTAL PASSAGE...WITH A FEW ISOLATED SHOWERS POSSIBLE. HOWEVER...WITH A PERSISTANT DRY BOUNDARY LAYER...THE LIKELIHOOD OF ANY PRECIPITATION ACTUALLY REACHING THE GROUND IS RATHER MINIMAL. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 235 PM CDT THU MAY 5 2016 COOLER AIR WILL SETTLE INTO THE AREA THIS WEEKEND IN THE WAKE OF FRIDAYS COLD FRONT. HOWEVER... PLEASANT TEMPERATURES ARE STILL EXPECTED WITH HIGHS MAINLY IN THE 70S. DRY CONDITIONS WILL REMAIN. CHANGES APPEAR ON THE HORIZON FOR THE START THE WORK WEEK AS AN UPPER LOW CURRENTLY OFF THE CALIFORNIA COAST DEEPENS OVER THE FOUR CORNERS REGION THIS WEEKEND AND LIFTS INTO THE PLAINS ON MONDAY...BRINGING CHANCES FOR RAIN AND THUNDERSTORMS. CHANCES FOR RAIN AND THUNDERSTORMS WILL LINGER OVER THE AREA THROUGH THE WEEK AS THE GFS AND ECMWF HAVE THE LOW REMAINING NEARBY THROUGH FRIDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1237 AM CDT FRI MAY 6 2016 VFR CONDITIONS ARE FORECAST OVERNIGHT THROUGH FRIDAY...BUT THERE IS A LOW PROBABILITY OF SUB-VFR SMOKE AFFECTING PARTS OF THE AREA. THE MAIN AVIATION WEATHER ISSUE WILL BE A COLD FRONTAL PASSAGE THAT HAS ARRIVED AT KISN...WHICH HAS SHIFTED WINDS TO THE NORTH. EXPECT WINDS TO BEGIN INCREASING A FEW HOURS AFTER FRONTAL PASSAGE WITH NORTHERLY WIND GUSTS TO AROUND 30 KT EXPECTED TO OCCUR FRIDAY LATE MORNING AND AFTERNOON ACROSS ALL OF WESTERN AND CENTRAL ND. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...AJ LONG TERM...AJ AVIATION...JV
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
150 AM EDT FRI MAY 6 2016 .SYNOPSIS... UNSEASONABLY COOL AIR WILL CONTINUE TO FILTER IN FROM THE NORTHWEST IN THE WAKE OF A COLD FRONT. THE WEATHER WILL REMAIN UNSETTLED AS A DEEP UPPER LOW CENTER MOVES ACROSS THE CAROLINAS TONIGHT AND AWAY TO THE NORTHEAST ON FRIDAY. ANOTHER FRONT IS EXPECTED TO STALL JUST TO OUR NORTH ON SATURDAY AND SUNDAY. THE FRONT SHOULD LIFT BACK TO THE NORTH ON MONDAY...AS HIGH PRESSURE OFF THE SOUTHEAST COAST EXPANDS AND WARM SOUTHERLY FLOW RETURNS. && .NEAR TERM /THROUGH TODAY/... AS OF 1015 PM EDT...ABUNDANT MOISTURE MOVING SOUTHWARD ALONG THE SPINE OF THE MOUNTAINS IS ENCOUNTERING WET BULB PROFILES JUST COLD ENOUGH ABOVE ABOUT 4000 FEET TO CHANGE THE PREDOMINANT PRECIPITATION TYPE OVER TO SNOW. ALTHOUGH THERE ARE MODEL HINTS OF SLIGHT WARMING OVERNIGHT...IF ALL OR MOST OF THE IMPENDING QPF IS PREDOMINATELY SNOW AT THE HIGHER ELEVATIONS...ENOUGH ACCUMULATION SHOULD DEVELOP FOR SLIPPERY ROADWAYS AND ASSOCIATED IMPACTS TO MANIFEST THEMSELVES. A WINTER WEATHER ADVISORY HAS BEEN POSTED FOR AVERY AND MITCHELL COUNTIES ABOVE 3500 FEET AT THIS POINT. THE ELEVATION DEPENDENCE WILL BE STRONG...WITH MAINLY RAIN BELOW 3500 FEET...ABOUT AN INCH AT 3500 FEET RANGING UP TO SIX INCHES ABOVE 5000 FEET. OTHERWISE...WATER VAPOR IMAGERY AND RAP 500 MB HEIGHTS CONTINUE TO INDICATE THAT THE 546 DM LOW CENTER HAS MOVED EAST OF THE CLT METRO AREA. MOISTURE AND SPOKES OF 500 MB VORTICITY CONTINUE TO ROTATE SOUTH ACROSS THE FORECAST AREA AROUND THE BACK SIDE OF THE LOW PRESSURE SYSTEM. THIS WILL LEAD TO FAIRLY HIGH COVERAGE OF LIGHT RAIN/SHOWERS ACROSS THE NORTHERN TIER...WITH ELEVATIONS ABOVE ABOUT 4000 FEET COLD ENOUGH FOR SNOW AT TIMES IN THE NORTHERN MOUNTAINS. SOME WARMING IS POSSIBLE OVERNIGHT. THE SHOWER COVERAGE WILL BE MUCH SPOTTIER IN SOUTHERN SECTIONS WITH MAINLY PERIODS OF CLOUDS. THE LOW WILL MOVE TOWARD THE CAROLINA COAST OVERNIGHT INTO FRIDAY...AND THE BEST Q VECTOR CONVERGENCE WILL BE TO OUR EAST. THE SETUP WILL BE SOMEWHAT SIMILAR ON FRIDAY...AS THE LOW REMAINS OVER THE MID-ATLANTIC COAST. LAPSE RATES WILL BE SLIGHTLY POORER WITH THE BETTER COLD AIR OFF TO THE EAST...BUT TEMPS/DEWPTS REBOUND BY 5-7 DEGREES...AND THESE SUGGEST SOME INSTABILITY WILL REDEVELOP. CHANCES OVERALL ARE LESSER WITH MODEL QPF BEING LESS WIDESPREAD. BREEZY TO WINDY CONDITIONS WILL RESULT WITH DEEP MIXING. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... AS OF 225 PM THURSDAY...ONE MORE POCKET OF COLD AIR ROTATES AROUND THE UPPER LOW AND ACROSS THE AREA FRIDAY NIGHT BEFORE WARMER MID LEVEL AIR MOVES IN ON SATURDAY. THIS WILL COMBINE WITH THE LINGERING LOW LEVEL MOISTURE ACROSS THE MOUNTAINS TO KEEP ISOLATED TO SCATTERED SHOWERS THERE DURING THE EVENING BEFORE ENDING BY MIDNIGHT. A WEAK WARM FRONT TRAILING FROM A SURFACE LOW OVER THE GREAT LAKES WILL BRUSH THE MOUNTAINS ON SATURDAY CREATING THE POTENTIAL FOR ISOLATED SHOWERS. FINALLY...A BACK DOOR COLD FRONT DROPS INTO THE AREA BY SUNDAY AS THE GREAT LAKES LOW MOVES EAST. SOME WEAK SHORT WAVE ENERGY WILL CROSS THE AREA SATURDAY NIGHT AND SUNDAY EVEN AS HEIGHTS RISE BETWEEN THE DEPARTING UPPER LOW AND A RIDGE DEVELOPING OVER THE CENTRAL CONUS. BEST CHANCE FOR CONVECTION WILL BE THE NORTHERN NC MOUNTAINS...WITH ISOLATED CONVECTION POSSIBLE ACROSS THE I-40 CORRIDOR. TEMPS REBOUND TO NEAR NORMAL LEVELS ON SATURDAY THEN RISE TO NEARLY 10 DEGREES ABOVE NORMAL ON SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 245PM THURSDAY...THE EXTENDED PERIOD BEGINS SUNDAY NIGHT WITH A STALLED FRONTAL BOUNDARY DRAPED W TO E ACROSS THE REGION UNDERNEATH FAIRLY ZONAL FLOW ALOFT. THE BOUNDARY WILL RETREAT NORTH AS A WARM FRONT AS SUBTROPICAL HIGH PRESSURE OVER THE SARGASSO SEA INDUCES WARM SOUTHERLY FLOW ACROSS THE REGION BEGINNING MONDAY AFTERNOON AND PERSISTING THROUGH AT LEAST WEDNESDAY. THE RETURN FLOW WILL ALLOW TEMPERATURES TO QUICKLY REBOUND TO GENERALLY 5-10 DEGREES ABOVE NORMAL THROUGH MID TO LATE WEEK. DEWPOINTS WILL GRADUALLY RETURN TO THE UPPER 50S AND LOWER 60S DURING THIS TIME AS WELL AND WITH THE INCREASING DIURNAL INSTABILITY...THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY. THE ECMWF REMAINS LESS OPTIMISTIC ABOUT COVERAGE THROUGH MID-WEEK WHILE THE GFS MAINTAINS SCATTERED TO WIDESPREAD COVERAGE EACH AFTERNOON. THIS APPEARS LARGELY TO BE THE RESULT OF STRONGER PERTURBATIONS IN THE WSW FLOW ALOFT ENHANCING OVERALL FORCING IN THE GFS COMPARED TO THE FAIRLY BENIGN ECMWF SOLUTION. THE FORECAST THEREFORE REFLECTS A BLEND OF THE GUIDANCE AS THE PATTERN CERTAINLY WARRANTS SLIGHT CHANCE COVERAGE EAST AND CHANCE COVERAGE WEST. AN OPPORTUNITY EXISTS FOR MORE WIDESPREAD COVERAGE OF SHOWERS AND STORMS WEDNESDAY EVENING INTO FRIDAY AS ANOTHER CLOSED LOW DROPS INTO THE UPPER MIDWEST AND GREAT LAKES REGIONS AND A FEW LOBES OF VORTICITY ROTATE AROUND THE BASE OF THE LOW ACROSS THE OH AND TN VALLEYS AND INTO VIRGINIA AND THE CAROLINAS. HOWEVER...GIVEN THE SOMEWHAT ANOMALOUS NATURE OF THIS PATTERN...AGAIN THE GUIDANCE DIFFERS ON THE EXACT PLACEMENT AND EVOLUTION OF THE UPPER-LEVEL FLOW. WHILE POPS INCREASE SLIGHTLY INTO LATE WEEK IN RESPONSE TO THE ANTICIPATED BETTER FORCING ALOFT...THERE IS TOO MUCH UNCERTAINTY TO WARRANT MORE AGGRESSIVE COVERAGE ATTM. FOR NOW...THESE FEATURES DO LITTLE TO CHANGE THE ABOVE NORMAL TEMPERATURES WE EXPECT THROUGH THE END OF NEXT WEEK. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AT KCLT AND ELSEWHERE...STILL SEEING SHOWERS WORKING THEIR WAY ACROSS THE AREA ON THE BACK SIDE OF THE UPPER LOW. INCREASING DOWNSLOPING COMPONENT WILL HELP TO DRY THINGS OUT...THOUGH EXPECT SOME LINGERING VCSH OR -SHRA FOR A FEW HOURS STILL. BEST CHANCE FOR MVFR CIGS REMAINS AT KHKY BUT FOR THE MOST PART EVERYONE SHOULD BE VFR THROUGH THE PERIOD. CANNOT RULE OUT SOME -SHRA THIS AFTERNOON BUT WITH THE UPPER LOW BEGINNING TO MOVE AWAY CHANCES DO NOT QUITE SUPPORT PROB30...BUT WILL REEVALUATE FOR THE 12Z TAFS. OTHERWISE... CONTINUED DEEP MIXING WITH STEEP LAPSE RATES WILL SUPPORT ANOTHER ROUND OF GUSTY N/NNW WINDS TODAY...WITH PEAK GUSTS 20-30KT ESPECIALLY TOWARD KAVL. OUTLOOK...DRYING WILL CONTINUE INTO SATURDAY. A COLD FRONT WILL APPROACH FROM THE NORTH SUNDAY...WITH ASSOCIATED PRECIPITATION POSSIBLY APPROACHING KAVL TO KHKY BEFORE THE FRONT STALLS. WARMING CONDITIONS WITH A RETURN TO SW FLOW ARE EXPECTED THROUGH EARLY NEXT WEEK. CONFIDENCE TABLE... 06-12Z 12-18Z 18-24Z 00-06Z KCLT HIGH 99% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 94% HIGH 97% HIGH 100% HIGH 100% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULE TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLET HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...WINTER WEATHER ADVISORY UNTIL NOON EDT TODAY FOR NCZ033-050. SC...NONE. && $$ SYNOPSIS...HG/JMP NEAR TERM...HG SHORT TERM...RWH LONG TERM...JMP AVIATION...TDP
AREA FORECAST DISCUSSION
NWS PORTLAND OR
207 AM PDT FRI MAY 6 2016 .SYNOPSIS...HIGH PRESSURE BUILDING ACROSS THE REGION WILL BRING WARMER TEMPERATURES AND PLENTY OF SUNSHINE FRIDAY AND SATURDAY. A WEAK FRONT WILL BRING MARINE CLOUDS AND AREAS OF DRIZZLE AND LIGHT SHOWERS SATURDAY NIGHT AND SUNDAY MORNING. EXPECT TEMPERATURES TO DROP MUCH CLOSER TO AVERAGE SUNDAY AND MONDAY. HIGH PRESSURE PUSHING BACK OVER THE REGION NEXT WEEK WILL BRING ANOTHER ROUND OF UNSEASONABLY WARM WEATHER. && .SHORT TERM...SATELLITE PICTURES SHOWED A LARGE UPPER LOW OFF THE S CA COAST...WITH THE NORTHWARD EXTENDING TROUGH AXIS RUNNING ROUGHLY UP THE PACIFIC NW COAST. MODELS CONTINUE THE PREVIOUS TREND OF INDICATING THE LOW MOVING SLOWLY E AND THEN NE THROUGH THE WEEKEND ACROSS THE DESERT SW. WHILE SURFACE PRES GRADIENTS REMAINED ONSHORE OVER THE FORECAST AREA EARLY FRI MORNING...THE LOW LEVEL FLOW ABOVE THE SURFACE WAS OFFSHORE OUT OF THE NE. THIS HAS RESULTED IN DRYING OVER THE AIR MASS AT LOW LEVELS...WITH LITTLE INDICATION IN SURFACE OBSERVATIONS THROUGH THE EARLY MORNING HOURS OF ANY MARINE CLOUDS REDEVELOPING. THE MOST LIKELY AREA IN THIS PATTERN FOR ANY LOW CLOUDS OR FOG TO DEVELOP IN THE MORNING WOULD BE ALONG THE CENTRAL OREGON COAST...SO WILL LEAVE A MENTION FOR CLOUDS AND FOG IN THIS MORNING. MODEL SOUNDINGS AGAIN HINTING AT SOME CONDITIONAL INSTABILITY OVER THE CASCADES THIS AFTERNOON...ALTHOUGH MOST MODEL QPF FIELDS GENERALLY INDICATE ANY THREAT OF PRECIPITATION WILL BE SUPPRESSED SE OF THE FORECAST AREA. WITH THE INCREASINGLY EASTERLY MID AND UPPER LEVEL FLOW TODAY WILL HANG ON TO A CHANCE FOR AFTERNOON AND EVENING THUNDERSTORMS OVER THE S PART OF THE CASCADES. WILL CONTINUE WITH A DRY AND MOSTLY SUNNY FORECAST INTO SAT AS THE UPPER LOW CONTINUES TO MOVE E AND A SW TO NE ORIENTED UPPER RIDGE SINKS DOWN OVER THE REGION SAT. SUBSIDENCE WILL RESULT IN WARMING TEMPS AGAIN FRI AND SAT. SAT NIGHT INTO SUN MODELS CONTINUE TO AGREE ON A EITHER A WEAK COLD FRONT OR A STRONG NW MARINE PUSH...YOU DECIDE. EITHER WAY DEEP MARINE MOISTURE MOVES IN SAT NIGHT AS THE UPPER FLOW TURNS NW BEHIND A SHORTWAVE CUTTING ACROSS WA. WITH SOME DYNAMICS AND LOW LEVEL MOISTURE WILL KEEP IN CHANCES FOR DRIZZLE MOVING IN SAT NIGHT...THEN SOME DRIZZLE OR LIGHT SHOWERS MAINLY IN THE MORNING SUN. COOLER TEMPS ALSO IN STORE...AND MORE IN LINE WITH CLIMATOLOGY WITH THE MARINE AIR MASS. && .LONG TERM...AN UPPER TROUGH OVER THE INTERIOR PACIFIC NW MON IS EXPECTED TO KEEP THE COOLER AIR AND MARINE CLOUDS IN PLACE THROUGH MON MORNING. GENERAL TREND WITH MODELS OVER THE NEXT SEVERAL DAYS HAS HEIGHTS BUILDING OVER THE REGION AS AN OFFSHORE RIDGE NUDGES EASTWARD. WITH A THERMALLY INDUCED TROUGH EXPECTED TO BUILD UP ALONG THE OREGON COAST TUE THE RESULTING LOW LEVEL OFFSHORE FLOW WILL BRINGING DRY AND MOSTLY SUNNY WEATHER WITH WARMING TEMPS THROUGH THE WEEK. BY THU GFS AND EC AGREE ON H8 TEMPS REACHING 15 TO 16 DEG C...WHICH SHOULD BE GOOD FOR HIGHS BACK INTO THE MID 80S IN THE INLAND VALLEYS. WARMEST TEMPS ON THE COAST HOWEVER APPEAR LIKELY TO COME ON WED...AS ONSHORE FLOW RETURNS LATER IN THE WEEK WITH THE SURFACE TROUGH AXIS MOVING INLAND. && .AVIATION...VFR ACROSS THE BOARD EARLY THIS MORNING. THERE MAY BE SOME LOCALIZED LOW-END MVFR OR HIGH-END IFR CIGS ALONG THE CENTRAL OREGON COAST THROUGH 16Z OR SO. THERE IS ALSO A CHANCE OF MVFR CIGS BETWEEN KCVO AND KEUG 12Z TO 16Z. OTHERWISE...VFR CONDITIONS TO PREVAIL THROUGH 06Z SAT. NORTH WIND GUSTS 20-30 KT ALONG THE CENTRAL COAST FRI AFTERNOON THROUGH EARLY EVENING. KPDX AND APPROACHES...VFR CONDITIONS THROUGH FRI EVENING. WEISHAAR && .MARINE...HIGH PRES OVER THE WATERS FOR THE NEXT FEW DAYS. PRIMARY MARINE ISSUE WILL BE SMALL CRAFT WIND ADVISORY TIMING. 00Z NAM AND GFS SHOW WIND SPEEDS EASING JUST A BIT FRI MORNING...BUT INCREASING AGAIN IN THE AFTERNOON. OUTER WATERS WILL REMAIN IN SMALL CRAFT ADVISORY WIND CONDITIONS THROUGH AT LEAST SAT EVENING...IF NOT A LITTLE LONGER. 00Z NAM SHOWS 30 KT BOUNDARY LAYER SUSTAINED SPEEDS OVER PZZ275 FRI AFTERNOON THROUGH THE EVENING...WITH 975MB SPEEDS PUSHING 40 KT. CONTEMPLATED GOING WITH A GALE WARNING FOR PZZ275...BUT FOR NOW WILL MAINTAIN UPPER-END SMALL CRAFT ADVISORY WIND SPEEDS. INNER WATERS GET COMPLICATED. WENT WITH A NEW SMALL CRAFT WIND ADVISORY FOR PZZ255 18Z THIS MORNING THROUGH 09Z SAT. EXPECT GUSTS UP TO 30 KT. NORTHERN INNER WATERS...PZZ250...SHOULD SEE WIND SPEEDS REACHING SMALL CRAFT ADVISORY LEVELS BY EARLY AFTERNOON...AND ENDING A LITTLE SOONER THAN PZZ255. COLD FRONT...OR MORE LIKE A STRONG MARINE SURGE...OCCURS SUN...WHICH WILL TURN THE WIND MORE OUT OF THE NW. STRONGEST SPEEDS EXPECTED TO SWITCH TO THE NRN OUTER WATERS SUN. WIND SPEEDS FINALLY FALL BELOW 20 KT MON...AND SHIFT NORTH TO NORTHEAST MON NIGHT AS A THERMALLY-INDUCED SURFACE LOW DEVELOPS ALONG THE COASTLINE. WIND-DRIVEN SEAS WILL CONTINUE THE CHOPPY CONDITIONS WITH SQUARE SEAS AT TIMES. HIGHEST SEAS TODAY THROUGH SATURDAY WILL BE IN PZZ275 WHERE WIND-WAVES UP TO 8 FT ARE LIKELY. WEISHAAR && .PQR WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT SATURDAY FOR WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR FROM 10 TO 60 NM. SMALL CRAFT ADVISORY FOR WINDS FROM 1 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 10 NM. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM PDT SATURDAY FOR WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM. SMALL CRAFT ADVISORY FOR WINDS FROM 11 AM THIS MORNING TO 2 AM PDT SATURDAY FOR COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM. SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 7 AM PDT THIS MORNING. SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 4 PM THIS AFTERNOON TO 7 PM PDT THIS EVENING. && $$ INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/NWSPORTLAND WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
Area Forecast Discussion National Weather Service Spokane WA 1055 PM PDT THU MAY 5 2016 .SYNOPSIS... Most of the Inland NW will see dry and mild conditions Friday through the weekend. However breezy to locally windy conditions are expected at times...especially Sunday afternoon and evening as a strong cold front passes through. Cooler and unsettled weather is expected on Monday before a warming trend begins again for the middle of next week. && .DISCUSSION... Update: Large closed low moving towards the southern California coast tonight continues to pump moisture up from the south into southeast Washington into the south Idaho Panhandle. Storms earlier this evening over NE Oregon have moved into the Blue Mountains, Camas Prairie, and Lewiston area as of 945 pm, with another cell between St. Maries and Clarkia. Yet another batch of storms is approaching Kamiah. The forecast for tonight has been updated based on current radar and lightning trends. The NAM shows most unstable CAPE values of 200-500 J/KG persisting into the overnight hours in these areas and thus a chance of thunderstorms was extended into the overnight hours. Elsewhere drier north- northeast flow in the lower levels as well as more stability in the mid levels should keep dry conditions persisting into the overnight hours. JW && .AVIATION... 06Z TAFS: Showers and isolated thunderstorms will continue tonight over far SE Washington into the south Idaho Panhandle. This will moisten the boundary layer and could led to areas of stratus by sunrise near KPUW/KLWS. But for now kept prevailing conditions MVFR due to only light rain amounts near KPUW/KLWS with the best chance of stratus east of these TAF sites. Otherwise a tight northerly pressure gradient develops tonight which will result in increasing north- northeast winds especially at KMWH/KCOE by Friday morning. Friday afternoon the best chance of thunderstorms will be over the mountains near Lewiston as the increasing north- northeast winds helps dry out the lower level air mass over much of Central and Northeast Washington into the north Idaho Panhandle. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 54 77 54 81 55 76 / 10 10 10 0 0 10 Coeur d`Alene 49 76 50 81 52 75 / 20 10 10 10 0 10 Pullman 49 75 49 78 51 72 / 50 10 10 10 0 10 Lewiston 53 81 54 83 56 78 / 50 20 10 10 10 10 Colville 45 81 47 85 48 80 / 10 10 10 0 0 10 Sandpoint 47 74 44 79 46 73 / 20 10 10 0 0 20 Kellogg 45 73 44 79 46 72 / 50 10 10 10 0 20 Moses Lake 52 83 53 86 52 80 / 10 10 0 0 0 0 Wenatchee 54 82 57 86 58 77 / 10 10 0 0 0 0 Omak 48 81 53 85 52 79 / 10 10 0 0 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
Area Forecast Discussion National Weather Service Spokane WA 958 PM PDT THU MAY 5 2016 .SYNOPSIS... Isolated showers and thunderstorms will be possible mainly across southeast Washington into the Idaho Panhandle this evening. Some storms will be capable of heavy rainfall...hail...and gusty winds. Improving but breezy conditions will begin on Friday, lasting through the weekend. More unsettled and cooler weather is expected next week. && .DISCUSSION... Update: Large closed low moving towards the southern California coast tonight continues to pump moisture up from the south into southeast Washington into the south Idaho Panhandle. Storms earlier this evening over NE Oregon have moved into the Blue Mountains, Camas Prairie, and Lewiston area as of 945 pm, with another cell between St. Maries and Clarkia. Yet another batch of storms is approaching Kamiah. The forecast for tonight has been updated based on current radar and lightning trends. The NAM shows most unstable CAPE values of 200-500 J/KG persisting into the overnight hours in these areas and thus a chance of thunderstorms was extended into the overnight hours. Elsewhere drier north- northeast flow in the lower levels as well as more stability in the mid levels should keep dry conditions persisting into the overnight hours. JW && .AVIATION... 00Z TAFS: Main aviation concern is the potential for thunderstorms mainly over southeast Washington and the south Idaho Panhandle this evening which could impact the KLWS/KPUW TAF sites. Thus far the storms are weakening as they come off the Blue Mountains and the HRRR shows storms weakening this evening as they approach the KLWS/KPUW TAF sites. Thus for now confidence is only low to moderate of these sites being impacted and thus thunder was removed for now. However will be monitoring radar trends. Otherwise a tight northerly pressure gradient develops tonight which will result in increasing north-northeast winds especially at KMWH/KCOE by Friday morning. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 54 77 54 81 55 76 / 10 10 10 0 0 10 Coeur d`Alene 49 76 50 81 52 75 / 20 10 10 10 0 10 Pullman 49 75 49 78 51 72 / 20 10 10 10 0 10 Lewiston 53 81 54 83 56 78 / 50 20 10 10 10 10 Colville 45 81 47 85 48 80 / 10 10 10 0 0 10 Sandpoint 47 74 44 79 46 73 / 20 10 10 0 0 20 Kellogg 45 73 44 79 46 72 / 50 10 10 10 0 20 Moses Lake 52 83 53 86 52 80 / 10 10 0 0 0 0 Wenatchee 54 82 57 86 58 77 / 10 10 0 0 0 0 Omak 48 81 53 85 52 79 / 10 10 0 0 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
902 AM PDT FRI MAY 6 2016 .SYNOPSIS...A BROAD UPPER LEVEL LOW NOW CENTERED JUST OFF OF THE SOUTHERN CALIFORNIA COAST WILL SHIFT SLOWLY EASTWARD AND INLAND TODAY. BANDS OF MOISTURE ROTATING AROUND IT WILL MAINTAIN SHOWER CHANCES OVER OUR DISTRICT THROUGH SATURDAY EVENING. THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AS WELL...PRIMARILY MORE INLAND AREAS. PRECIP CHANCES WILL DIMINISH SATURDAY NIGHT AND SUNDAY MORNING...WITH DRY CONDITIONS THEN EXPECTED TO PREVAIL THROUGH THE REMAINDER OF THE FORECAST PERIOD. A GRADUAL WARMING TREND IS EXPECTED FOR THE FIRST HALF OF NEXT WEEK AS A RIDGE OF UPPER LEVEL HIGH PRESSURE BUILDS OVER THE WEST COAST. && .DISCUSSION...AS OF 9:00 AM PDT FRIDAY...SHOWERS EXPECTED TO RETURN TO OUR REGION SHORTLY. IN FACT HRRR IS FAIRLY BULLISH AND BRINGS AN AREA OF MOISTURE (WELL DEPICTED BY RADARS) TO MOST OF THE SF BAY REGION DOWN TO SANTA CRUZ AND SANTA CLARA COUNTY BY EARLY IN THE AFTERNOON. AFTER THAT SHOWERS CAN BE EXPECTED WITH ANOTHER ROUND OF RAIN FORECAST FOR TOMORROW. DID A MINOR UPDATE THIS MORNING TO THE FORECAST AND UPPED THE POPS FOR SATURDAY IN LIGHT OF LATEST GUIDANCE. ALSO ADDED A SLIGHT CHANCED FOR THUNDERSTORMS TO EASTERN PARTS OF THE CWA. RAINFALL AMOUNTS STILL FORECAST TO BE FAIRLY LIGHT WITH UNDER 1/4" IN MOST URBAN SPOTS. LOCAL RANGES COULD SEE UP TO 2/3". WILL UPDATE FORECAST TODAY AS NECESSARY BASED ON THE TRACK OF THE RAIN. .PREVIOUS DISCUSSION...LATEST KMUX RADAR DATA AND SURFACE OBS INDICATE DRY CONDITIONS NOW PREVAILING ACROSS MOST OF OUR DISTRICT...THOUGH WITH SOME SHOWERS HAVING JUST DEVELOPED OVER THE SOUTHERN SANTA LUCIA MTNS OF MONTEREY COUNTY. WATER VAPOR SATELLITE IMAGERY AND MODEL ANALYSIS SHOW A BROAD AND DIFFUSE UPPER LEVEL LOW NEAR THE SOUTHERN CALIFORNIA COAST...WITH ITS CENTER PRESENTLY IN THE VICINITY OF THE NORTHERN CHANNEL ISLANDS. THE SYNOPTIC SCALE WEATHER SITUATION FOR OUR AREA IS AN UNUSUAL ONE...WITH THE FLOW ALOFT ADVECTING IN A MOIST AND POTENTIALLY UNSTABLE AIR MASS FROM THE EAST. THE NEXT BAND OF CLOUDINESS IS SPREADING RAPIDLY WESTWARD INTO THE SF BAY AREA THROUGH THE MIDDLE OF THE CENTRAL VALLEY. THUS FAR HOWEVER...ASSOCIATED PRECIP HAS LARGELY BEEN CONFINED TO THE HIGHER ELEVATIONS OF THE SIERRA NEVADA WITH NEITHER KDAX NOR KMUX RADARS...OR SURFACE OBS...INDICATING ANY APPRECIABLE ASSOCIATED SHOWER ACTIVITY PRESENTLY MOVING TOWARDS US. AS A RESULT EXPECT THE DAY TO GET OFF TO A DRY START...AT LEAST THROUGH THE MORNING COMMUTE. THEREAFTER THOUGH CONFIDENCE DIMINISHES. MODEL PERFORMANCE IN GENERAL WITH THIS SYSTEM THUS FAR...IN TERMS OF TIMING AND LOCATION OF ASSOCIATED PRECIPITATION...HAS NOT BEEN PARTICULARLY IMPRESSIVE. AND EVEN IN THE SHORT TERM...WIDE VARIATION BETWEEN MODEL SOLUTIONS IN THIS RESPECT CONTINUES TO BE EVIDENT. THE NEW 06Z RUN OF THE GFS SHOWS PRECIP THIS AFTERNOON PRIMARILY CONFINED TO SANTA CLARA AND SAN BENITO COUNTIES...WHILE THE 06Z NAM SPREADS IT OVER ALMOST ALL OF OUR DISTRICT ASIDE FROM SONOMA COUNTY...THE LATEST (09Z) HRRR RUN STARTS THE SHOWER ACTIVITY IN THE LATE MORNING OVER THE NORTH BAY WITH IT THEN DIMINISHING AS IT MOVES SOUTHWARD THROUGH THE CENTRAL SF BAY AREA DURING THE AFTERNOON...AND THE LATEST AVAILABLE (00Z) OUTPUT FROM THE ECMWF MODEL FOCUSES IT ON THE FAR SE PORTION OF OUR CWA DURING THE AFTERNOON. AS A RESULT...VERY DIFFICULT TO NAIL DOWN DETAILS IN GRIDS AND FORECAST. THAT SAID HOWEVER...THERE IS MUCH BETTER AGREEMENT REGARDING THE GENERAL LARGER-SCALE PICTURE AND EVOLUTION. GOOD CONSENSUS THAT THE UPPER LEVEL LOW WILL TRACK GRADUALLY EASTWARD THROUGH FAR SOUTHERN CALIFORNIA AND INTO ARIZONA BY SUNDAY MORNING. BY THAT POINT ALL ASSOCIATED PRECIP SHOULD HAVE SHIFTED EASTWARD OF OUR DISTRICT...BUT UNTIL THEN SHOWER CHANCES WILL CONTINUE. THUNDERSTORMS WILL ALSO REMAIN POSSIBLE THROUGH THIS EVENING...PRIMARILY OVER THE MOUNTAINS AND MORE INLAND AREAS...AND THEN SHOULD DIMINISH AND COME TO AN END AS THE AIR MASS STABILIZES. FROM SUNDAY AFTERNOON THROUGH AT LEAST THE MIDDLE OF NEXT WEEK...DRY CONDITIONS AND A WARMING TREND ARE EXPECTED TO PREVAIL WITH GOOD LONGER RANGE MODEL AGREEMENT THAT AN UPPER LEVEL RIDGE WILL BUILD IN OVER THE WEST COAST. BOTH THE ECMWF AND GFS SIGNIFICANTLY RAISE 850 MB TEMPS AS THIS OCCURS...UP INTO THE 15C TO 17C RANGE BY WEDNESDAY AND THURSDAY WITH AFTERNOON HIGHS...AT LEAST INLAND AREAS...THEN PROJECTED TO REACH UP INTO THE 80S. && .AVIATION...AS OF 4:49 AM PDT FRIDAY...FOR 12Z TAFS. CHALLENGING FORECAST DETAILS GIVEN SYNOPTIC PATTERN. EXPECT IFR TO MVFR CIGS FROM NOW THROUGH ABOUT 16Z. THEN RAIN SHIELD CURRENTLY OVER THE SIERRA SHOULD ROTATE OVER BAY AREA FROM LATE MORNING THROUGH THE AFTERNOON WITH PERIODS OF RAIN AND MVFR CIGS. WINDS TO REMAIN MAINLY WNW AND LIGHT. PRECIP ACTIVITY TO SLOWLY ROTATE OVER MONTEREY BAY TERMINALS THROUGH EARLY EVENING. MOIST BOUNDARY LAYER LIKELY TO LEAVE LOW CIGS IN PLACE AGAIN TONIGHT...THEN A REPEAT PERFORMANCE SATURDAY MORNING AS ANOTHER BAND OF LIGHT RAIN ROTATING OFF THE SIERRA WILL LIKELY IMPACT BAY AREA TERMINALS. THIS WAS REFLECTED IN 30 HOUR TAFS FOR KSFO/KOAK IN SHOWING -RA RETURNING SATURDAY MORNING AROUND 14Z. VICINITY OF KSFO...LOW CONFIDENCE ON DETAILS IN TERMS OF FLUCTUATING CLOUD HEIGHTS. DO EXPECT WINDS TO REMAIN FAVORABLE FROM THE NW. -RA BAND CURRENTLY OVER THE SIERRA TO REACH KSFO AROUND 16-17Z THROUGH MOST OF THE AFTERNOON WITH MVFR CIGS. -RA TO END BY LATE AFTERNOON WITH VCSH TURNING TO PERSISTENT MVFR CLOUDS AGAIN TONIGHT. SFO BRIDGE APPROACH...SIMILAR TO KSFO. EXPECT FLUCTUATING CLOUD HEIGHTS THIS MORNING. COULD BE PERIOD OF VISUALS THROUGH 16-17Z BUT THEN AS PRECIP BAND ARRIVES BY MID TO LATE MORNING EXPECT THAT WINDOW TO CLOSE THROUGH THE AFTERNOON HOURS WITH PERIODS OF -RA AND MVFR CIGS. MONTEREY BAY TERMINALS...LOW CIGS THIS MORNING FROM 400 FEET AT KMRY TO 1600 FEET AT KSNS. VCSH WITH CHANGING CLOUD DECKS IN PLACE THIS MORNING. -RA TO ARRIVE THIS AFTERNOON AS PRECIP SHIELD ROTATES FROM NORTHEAST TO SOUTHWEST THROUGH THE DAY. && .MARINE...AS OF 9:00 AM PDT FRIDAY...A LOW PRESSURE STORM SYSTEM WILL SHIFT FARTHER INLAND TODAY BUT CONTINUE TO SPREAD RAIN SHOWERS OVER THE COASTAL WATERS. WINDS WILL BE SPLIT... WITH BREEZY NORTHERLY WINDS ACROSS THE NORTHERN OUTER WATERS AND LIGHT SOUTHERLY WINDS ALONG MUCH OF THE COAST AND THE SOUTHERN WATERS. SEAS WILL CONTINUE TO BE LIGHT THROUGH SATURDAY. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM && $$ PUBLIC FORECAST: BELL/BLIER AVIATION: R_WALBRUN MARINE: MWW VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK AND TWITTER AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
449 AM PDT FRI MAY 6 2016 .SYNOPSIS...A BROAD UPPER LEVEL LOW NOW CENTERED JUST OFF OF THE SOUTHERN CALIFORNIA COAST WILL SHIFT SLOWLY EASTWARD AND INLAND TODAY. BANDS OF MOISTURE ROTATING AROUND IT WILL MAINTAIN SHOWER CHANCES OVER OUR DISTRICT THROUGH SATURDAY EVENING. THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE THROUGH THIS EVENING...PRIMARILY MORE INLAND AREAS. PRECIP CHANCES WILL DIMINISH SATURDAY NIGHT AND SUNDAY MORNING...WITH DRY CONDITIONS THEN EXPECTED TO PREVAIL THROUGH THE REMAINDER OF THE FORECAST PERIOD. A GRADUAL WARMING TREND IS EXPECTED FOR THE FIRST HALF OF NEXT WEEK AS A RIDGE OF UPPER LEVEL HIGH PRESSURE BUILDS OVER THE WEST COAST. && .DISCUSSION...AS OF 4:20 AM PDT FRIDAY...LATEST KMUX RADAR DATA AND SURFACE OBS INDICATE DRY CONDITIONS NOW PREVAILING ACROSS MOST OF OUR DISTRICT...THOUGH WITH SOME SHOWERS HAVING JUST DEVELOPED OVER THE SOUTHERN SANTA LUCIA MTNS OF MONTEREY COUNTY. WATER VAPOR SATELLITE IMAGERY AND MODEL ANALYSIS SHOW A BROAD AND DIFFUSE UPPER LEVEL LOW NEAR THE SOUTHERN CALIFORNIA COAST...WITH ITS CENTER PRESENTLY IN THE VICINITY OF THE NORTHERN CHANNEL ISLANDS. THE SYNOPTIC SCALE WEATHER SITUATION FOR OUR AREA IS AN UNUSUAL ONE...WITH THE FLOW ALOFT ADVECTING IN A MOIST AND POTENTIALLY UNSTABLE AIR MASS FROM THE EAST. THE NEXT BAND OF CLOUDINESS IS SPREADING RAPIDLY WESTWARD INTO THE SF BAY AREA THROUGH THE MIDDLE OF THE CENTRAL VALLEY. THUS FAR HOWEVER...ASSOCIATED PRECIP HAS LARGELY BEEN CONFINED TO THE HIGHER ELEVATIONS OF THE SIERRA NEVADA WITH NEITHER KDAX NOR KMUX RADARS...OR SURFACE OBS...INDICATING ANY APPRECIABLE ASSOCIATED SHOWER ACTIVITY PRESENTLY MOVING TOWARDS US. AS A RESULT EXPECT THE DAY TO GET OFF TO A DRY START...AT LEAST THROUGH THE MORNING COMMUTE. THEREAFTER THOUGH CONFIDENCE DIMINISHES. MODEL PERFORMANCE IN GENERAL WITH THIS SYSTEM THUS FAR...IN TERMS OF TIMING AND LOCATION OF ASSOCIATED PRECIPITATION...HAS NOT BEEN PARTICULARLY IMPRESSIVE. AND EVEN IN THE SHORT TERM...WIDE VARIATION BETWEEN MODEL SOLUTIONS IN THIS RESPECT CONTINUES TO BE EVIDENT. THE NEW 06Z RUN OF THE GFS SHOWS PRECIP THIS AFTERNOON PRIMARILY CONFINED TO SANTA CLARA AND SAN BENITO COUNTIES...WHILE THE 06Z NAM SPREADS IT OVER ALMOST ALL OF OUR DISTRICT ASIDE FROM SONOMA COUNTY...THE LATEST (09Z) HRRR RUN STARTS THE SHOWER ACTIVITY IN THE LATE MORNING OVER THE NORTH BAY WITH IT THEN DIMINISHING AS IT MOVES SOUTHWARD THROUGH THE CENTRAL SF BAY AREA DURING THE AFTERNOON...AND THE LATEST AVAILABLE (00Z) OUTPUT FROM THE ECMWF MODEL FOCUSES IT ON THE FAR SE PORTION OF OUR CWA DURING THE AFTERNOON. AS A RESULT...VERY DIFFICULT TO NAIL DOWN DETAILS IN GRIDS AND FORECAST. THAT SAID HOWEVER...THERE IS MUCH BETTER AGREEMENT REGARDING THE GENERAL LARGER-SCALE PICTURE AND EVOLUTION. GOOD CONSENSUS THAT THE UPPER LEVEL LOW WILL TRACK GRADUALLY EASTWARD THROUGH FAR SOUTHERN CALIFORNIA AND INTO ARIZONA BY SUNDAY MORNING. BY THAT POINT ALL ASSOCIATED PRECIP SHOULD HAVE SHIFTED EASTWARD OF OUR DISTRICT...BUT UNTIL THEN SHOWER CHANCES WILL CONTINUE. THUNDERSTORMS WILL ALSO REMAIN POSSIBLE THROUGH THIS EVENING...PRIMARILY OVER THE MOUNTAINS AND MORE INLAND AREAS...AND THEN SHOULD DIMINISH AND COME TO AN END AS THE AIR MASS STABILIZES. FROM SUNDAY AFTERNOON THROUGH AT LEAST THE MIDDLE OF NEXT WEEK...DRY CONDITIONS AND A WARMING TREND ARE EXPECTED TO PREVAIL WITH GOOD LONGER RANGE MODEL AGREEMENT THAT AN UPPER LEVEL RIDGE WILL BUILD IN OVER THE WEST COAST. BOTH THE ECMWF AND GFS SIGNIFICANTLY RAISE 850 MB TEMPS AS THIS OCCURS...UP INTO THE 15C TO 17C RANGE BY WEDNESDAY AND THURSDAY WITH AFTERNOON HIGHS...AT LEAST INLAND AREAS...THEN PROJECTED TO REACH UP INTO THE 80S. && .AVIATION...AS OF 4:49 AM PDT FRIDAY...FOR 12Z TAFS. CHALLENGING FORECAST DETAILS GIVEN SYNOPTIC PATTERN. EXPECT IFR TO MVFR CIGS FROM NOW THROUGH ABOUT 16Z. THEN RAIN SHIELD CURRENTLY OVER THE SIERRA SHOULD ROTATE OVER BAY AREA FROM LATE MORNING THROUGH THE AFTERNOON WITH PERIODS OF RAIN AND MVFR CIGS. WINDS TO REMAIN MAINLY WNW AND LIGHT. PRECIP ACTIVITY TO SLOWLY ROTATE OVER MONTEREY BAY TERMINALS THROUGH EARLY EVENING. MOIST BOUNDARY LAYER LIKELY TO LEAVE LOW CIGS IN PLACE AGAIN TONIGHT...THEN A REPEAT PERFORMANCE SATURDAY MORNING AS ANOTHER BAND OF LIGHT RAIN ROTATING OFF THE SIERRA WILL LIKELY IMPACT BAY AREA TERMINALS. THIS WAS REFLECTED IN 30 HOUR TAFS FOR KSFO/KOAK IN SHOWING -RA RETURNING SATURDAY MORNING AROUND 14Z. VICINITY OF KSFO...LOW CONFIDENCE ON DETAILS IN TERMS OF FLUCTUATING CLOUD HEIGHTS. DO EXPECT WINDS TO REMAIN FAVORABLE FROM THE NW. -RA BAND CURRENTLY OVER THE SIERRA TO REACH KSFO AROUND 16-17Z THROUGH MOST OF THE AFTERNOON WITH MVFR CIGS. -RA TO END BY LATE AFTERNOON WITH VCSH TURNING TO PERSISTENT MVFR CLOUDS AGAIN TONIGHT. SFO BRIDGE APPROACH...SIMILAR TO KSFO. EXPECT FLUCTUATING CLOUD HEIGHTS THIS MORNING. COULD BE PERIOD OF VISUALS THROUGH 16-17Z BUT THEN AS PRECIP BAND ARRIVES BY MID TO LATE MORNING EXPECT THAT WINDOW TO CLOSE THROUGH THE AFTERNOON HOURS WITH PERIODS OF -RA AND MVFR CIGS. MONTEREY BAY TERMINALS...LOW CIGS THIS MORNING FROM 400 FEET AT KMRY TO 1600 FEET AT KSNS. VCSH WITH CHANGING CLOUD DECKS IN PLACE THIS MORNING. -RA TO ARRIVE THIS AFTERNOON AS PRECIP SHIELD ROTATES FROM NORTHEAST TO SOUTHWEST THROUGH THE DAY. && .MARINE...AS OF 4:49 AM PDT FRIDAY...AN UPPER LOW OVER SOUTHERN CALIFORNIA WILL RESULT IN FAIRLY LIGHT PRESSURE GRADIENTS ACROSS THE REGION...EXCEPT OVER THE NORTHERN OUTER WATERS WHERE STRONGER NW WINDS PERSIST AND SMALL CRAFT ADVISORIES ARE IN EFFECT. THE LOW WILL KEEP THE THREAT OF SHOWERS IN THE FORECAST TODAY INTO SATURDAY. SEAS WILL BE LIGHT WITH PERIODS AROUND 10 SECONDS THROUGH SATURDAY. A LONG PERIOD SW SWELL WILL ENTER THE WATERS BY SUNDAY. HIGH PRESSURE RETURNS BY EARLY NEXT WEEK WITH A THERMAL TROUGH KEEPING THE STRONGEST WINDS OVER THE NORTHERN OUTER WATERS WHILE GENERALLY LIGHT WIND AND SEAS ARE FORECAST NEAR SHORE. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM && $$ PUBLIC FORECAST: BLIER AVIATION: R_WALBRUN MARINE: R_WALBRUN VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK AND TWITTER AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
437 AM PDT FRI MAY 6 2016 .SYNOPSIS...A BROAD UPPER LEVEL LOW NOW CENTERED JUST OFF OF THE SOUTHERN CALIFORNIA COAST WILL SHIFT SLOWLY EASTWARD AND INLAND TODAY. BANDS OF MOISTURE ROTATING AROUND IT WILL MAINTAIN SHOWER CHANCES OVER OUR DISTRICT THROUGH SATURDAY EVENING. THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE THROUGH THIS EVENING...PRIMARILY MORE INLAND AREAS. PRECIP CHANCES WILL DIMINISH SATURDAY NIGHT AND SUNDAY MORNING...WITH DRY CONDITIONS THEN EXPECTED TO PREVAIL THROUGH THE REMAINDER OF THE FORECAST PERIOD. A GRADUAL WARMING TREND IS EXPECTED FOR THE FIRST HALF OF NEXT WEEK AS A RIDGE OF UPPER LEVEL HIGH PRESSURE BUILDS OVER THE WEST COAST. && .DISCUSSION...AS OF 4:20 AM PDT FRIDAY...LATEST KMUX RADAR DATA AND SURFACE OBS INDICATE DRY CONDITIONS NOW PREVAILING ACROSS MOST OF OUR DISTRICT...THOUGH WITH SOME SHOWERS HAVING JUST DEVELOPED OVER THE SOUTHERN SANTA LUCIA MTNS OF MONTEREY COUNTY. WATER VAPOR SATELLITE IMAGERY AND MODEL ANALYSES SHOW A BROAD AND DIFFUSE UPPER LEVEL LOW NEAR THE SOUTHERN CALIFORNIA COAST...WITH ITS CENTER PRESENTLY IN THE VICINITY OF THE NORTHERN CHANNEL ISLANDS. THE SYNOPTIC SCALE WEATHER SITUATION FOR OUR AREA IS AN UNUSUAL ONE...WITH THE FLOW ALOFT ADVECTING IN A MOIST AND POTENTIALLY UNSTABLE AIR MASS FROM THE EAST. THE NEXT BAND OF CLOUDINESS IS SPREADING RAPIDLY WESTWARD INTO THE SF BAY AREA THROUGH THE MIDDLE OF THE CENTRAL VALLEY. THUS FAR HOWEVER...ASSOCIATED PRECIP HAS LARGELY BEEN CONFINED TO THE HIGHER ELEVATIONS OF THE SIERRA NEVADA WITH NEITHER KDAX NOR KMUX RADARS...OR SURFACE OBS...INDICATING ANY APPRECIABLE ASSOCIATED SHOWER ACTIVITY PRESENTLY MOVING TOWARDS US. AS A RESULT EXPECT THE DAY TO GET OFF TO A DRY START...AT LEAST THROUGH THE MORNING COMMUTE. THEREAFTER THOUGH CONFIDENCE DIMINISHES. MODEL PERFORMANCE IN GENERAL WITH THIS SYSTEM THUS FAR...IN TERMS OF TIMING AND LOCATION OF ASSOCIATED PRECIPITATION...HAS NOT BEEN PARTICULARLY IMPRESSIVE. AND EVEN IN THE SHORT TERM...WIDE VARIATION BETWEEN MODEL SOLUTIONS IN THIS RESPECT CONTINUES TO BE EVIDENT. THE NEW 06Z RUN OF THE GFS SHOWS PRECIP THIS AFTERNOON PRIMARILY CONFINED TO SANTA CLARA AND SAN BENITO COUNTIES...WHILE THE 06Z NAM SPREADS IT OVER ALMOST ALL OF OUR DISTRICT ASIDE FROM SONOMA COUNTY...THE LATEST (09Z) HRRR RUN STARTS THE SHOWER ACTIVITY IN THE LATE MORNING OVER THE NORTH BAY WITH IT THEN DIMINISHING AS IT MOVES SOUTHWARD THROUGH THE CENTRAL SF BAY AREA DURING THE AFTERNOON...AND THE LATEST AVAILABLE (00Z) OUTPUT FROM THE ECMWF MODEL FOCUSES IT ON THE FAR SE PORTION OF OUR CWA DURING THE AFTERNOON. AS A RESULT...VERY DIFFICULT TO NAIL DOWN DETAILS IN GRIDS AND FORECAST. THAT SAID HOWEVER...THERE IS MUCH BETTER AGREEMENT REGARDING THE GENERAL LARGER-SCALE PICTURE AND EVOLUTION. GOOD CONSENSUS THAT THE UPPER LEVEL LOW WILL TRACK GRADUALLY EASTWARD THROUGH FAR SOUTHERN CALIFORNIA AND INTO ARIZONA BY SUNDAY MORNING. BY THAT POINT ALL ASSOCIATED PRECIP SHOULD HAVE SHIFTED EASTWARD OF OUR DISTRICT...BUT UNTIL THEN SHOWER CHANCES WILL CONTINUE. THUNDERSTORMS WILL ALSO REMAIN POSSIBLE THROUGH THIS EVENING...PRIMARILY OVER THE MOUNTAINS AND MORE INLAND AREAS...AND THEN SHOULD DIMINISH AND COME TO AN END AS THE AIR MASS STABILIZES. FROM SUNDAY AFTERNOON THROUGH AT LEAST THE MIDDLE OF NEXT WEEK...DRY CONDITIONS AND A WARMING TREND ARE EXPECTED TO PREVAIL WITH GOOD LONGER RANGE MODEL AGREEMENT THAT AN UPPER LEVEL RIDGE WILL BUILD IN OVER THE WEST COAST. BOTH THE ECMWF AND GFS SIGNIFICANTLY RAISE 850 MB TEMPS AS THIS OCCURS...UP INTO THE 15C TO 17C RANGE BY WEDNESDAY AND THURSDAY WITH AFTERNOON HIGHS...AT LEAST INLAND AREAS...THEN PROJECTED TO REACH UP INTO THE 80S. && .AVIATION...AS OF 10:30 PM PDT THURSDAY...UPPER LEVEL LOW WEST OF THE CENTRAL COAST MOVING TOWARDS SOUTHERN CALIFORNIA. ISOLATED SHOWERS ARE CONFINED TO THE HILLS THIS EVENING WHILE PATCHY LOW CLOUDS ARE ALONG THE COAST. MVFR EXPECTED TO SPREAD OVER THE MRY BAY AREA THIS EVENING AND INTO THE SFO BAY AREA LATER TONIGHT. AN UPPER LEVEL DISTURBANCE ROTATING AROUND THE LOW WILL BRING A CHANCE OF SHOWERS TO THE AREA FRIDAY MORNING. THESE SHOWERS WILL BE COMING FROM THE NORTHEAST. MVFR CIGS EXPECTED MOST OF THE DAY FRIDAY. CANNOT RULE OUT AN ISOLATED THUNDERSTORM FRIDAY AFTERNOON. VICINITY OF KSFO...MVFR CIGS AFTER 12Z CONTINUING THROUGH THE REST OF THE DAY. SCATTERED SHOWERS AFTER 16Z. MAINLY LIGHT SOUTHWEST WINDS. SFO BRIDGE APPROACH...SIMILAR AS KSFO. MONTEREY BAY TERMINALS...MVFR CIGS AFTER 08Z. A FEW SHOWERS POSSIBLE AFTER 17Z. && .MARINE...AS OF 10:30 PM PDT THURSDAY...AN UPPER LOW OVER SOUTHERN CALIFORNIA WILL RESULT IN FAIRLY LIGHT PRESSURE GRADIENTS ACROSS THE REGION...EXCEPT OVER THE NORTHERN OUTER WATERS WHERE STRONGER NW WINDS PERSIST AND SMALL CRAFT ADVISORIES ARE IN EFFECT. THE LOW WILL KEEP THE THREAT OF SHOWERS IN THE FORECAST TODAY INTO SATURDAY. SEAS WILL BE LIGHT WITH PERIODS AROUND 10 SECONDS THROUGH SATURDAY. A LONG PERIOD SW SWELL WILL ENTER THE WATERS BY SUNDAY. HIGH PRESSURE RETURNS BY EARLY NEXT WEEK WITH A THERMAL TROUGH KEEPING THE STRONGEST WINDS OVER THE NORTHERN OUTER WATERS WHILE GENERALLY LIGHT WIND AND SEAS ARE FORECAST NEAR SHORE. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM && $$ PUBLIC FORECAST: BLIER AVIATION: W PI MARINE: R_WALBRUN VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK AND TWITTER AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS EUREKA CA
427 AM PDT FRI MAY 6 2016 .SYNOPSIS...AN UPPER LEVEL LOW WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND POSSIBLY SATURDAY AFTERNOON. THEN BUILDING HIGH PRESSURE WILL BRING DRY WEATHER BACK TO THE REGION WITH A WARMING TREND FOR EARLY NEXT WEEK. && .DISCUSSION...A CLOSED UPPER LOW ACROSS THE SOUTHWESTERN UNITED STATES WILL DOMINATE THE WEATHER PATTERN BRINGING UNSEASONABLY COOL TEMPERATURES AND AFTERNOON THUNDERSTORMS THROUGH SATURDAY. SHOWERS AND THUNDERSTORMS SHOULD ORIGINATE OVER INTERIOR MOUNTAINS AND TRAVEL WESTWARD THROUGH THE DAY POSSIBLY IMPACTING COASTAL AREAS. THE STRONGEST INSTABILITY WILL BE ACROSS THE INTERIOR LATE THIS AFTERNOON WITH CONVECTIVE PARAMETERS WEAKENING BY SATURDAY AFTERNOON AS THE UPPER LOW BEGINS TO SHIFT EAST. THE HRRR INDICATES THERE WILL BE AN INITIAL BAND OF SHOWER ACTIVITY THIS MORNING ACROSS MENDOCINO COUNTY WITH AFTERNOON CONVECTION SPINNING UP WITH THE HEAT OF THE DAY ACROSS THE HIGHER TERRAIN OF TRINITY AND INTERIOR MENDOCINO COUNTIES. EXPECT STRONGER SHOWERS/STORMS TO WEAKEN AS THEY APPROACH THE COAST LATE THIS AFTERNOON BUT A RUMBLE OF THUNDER WILL CERTAINLY BE POSSIBLE NEAR THE COAST. A RIDGE OF HIGH PRESSURE WILL BUILD IN BEHIND THE EXITING UPPER LOW AND BRING AN END TO SHOWER ACTIVITY AND A WARMING TREND TO NORTHERN CALIFORNIA. SOME ISOLATED SHOWERS WILL BE POSSIBLE ACROSS INTERIOR MOUNTAINS SUNDAY AFTERNOON WITH THE WARMING/DRYING TREND UNFOLDING THROUGH EARLY NEXT WEEK. TEMPERATURES WILL SURPASS NORMAL VALUES FOR THIS TIME OF YEAR PARTICULARLY ACROSS INTERIOR LOCATIONS. HOWEVER, EASTERLY FLOW SHOULD DEVELOP EARLY NEXT WEEK AS THE THERMAL TROUGH SHIFTS WESTWARD AND BRINGS WARMER, DRY AIR TO COASTAL REGIONS. DESPITE MOSTLY SUNNY CONDITIONS FOR MUCH OF NORTHERN CALIFORNIA EARLY NEXT WEEK, THE SURFACE FLOW PATTERN SUGGESTS THAT STRATUS WILL MAKE A RETURN TO PARTS THE COAST. LITTLE CHANGES WERE OTHERWISE MADE TO THE EXTENDED FORECAST. KML && .AVIATION...LOW CEILINGS WITH REDUCED VISIBILITIES IN FOG WILL CONTINUE INTO THE MORNING HOURS ALONG THE REDWOOD COAST. ALTHO KCEC IS PRESENTLY SOCKED IN WITH 1SM VISIBILITY IN FOG... HIGH RESOLUTION MODELS ARE PROGGING INCREASING OFFSHORE...AND THUS DOWNSLOPE...FLOW AT KCEC. THIS SHOULD BE ENUF TO ERODE LOW CLOUDS AND FOG LATER THIS MORNING...WHILE LOW CLOUDS MAY LINGER INTO THE AFTERNOON OR LONGER AT KACV. LOW CLOUDS HAVE BROKEN UP AT KUKI. MID CLOUDS SHOULD LIMIT ADDITIONAL RADIATIVE COOLING...AND LIMITED SURROUNDING OBS DON`T INDICATE PRESENCE OF LOW CLOUDS. UNCERTAINTY IS HIGH...BUT WILL PROBABLY REMOVE LOW CEILING WITH NEXT TAF PACKAGE. WINDS WILL BECOME GUSTY AT KCEC DURING THE AFTERNOON. /SEC && .MARINE...THE TIGHT GRADIENT BETWEEN STRONG OFFSHORE HIGH PRESSURE AND INLAND LOW PRESSURE WILL MAINTAIN STRONG WINDS FOR THE NEXT FEW DAYS...ESPECIALLY OFFSHORE. HAVE EXTENDED ALL HEADLINES ANOTHER 6 HOURS OR SO. THE N OFFSHORE GALE WARNING CONTINUES THRU LATE TONIGHT...THE S OFFSHORE SMALL CRAFT ADVISORY AND HAZARDOUS SEAS WARNING CONTINUE THRU SAT MORNING...AND THE N NEAR SHORE SMALL CRAFT ADVISORY CONTINUES THRU SAT AFTERNOON. GRADIENT WINDS WILL WEAKEN SLIGHTLY OVER THE WEEKEND...BUT ADVISORY LEVEL WINDS WILL CONTINUE OVER THE N OFFSHORE WATERS. WINDS WILL MORE UNIFORMLY DIMINISH BY NEXT TUE. SHORT PERIOD...STEEP WAVES WILL DOMINATE INTO EARLY NEXT WEEK. /SEC && .EKA WATCHES/WARNINGS/ADVISORIES... CA...NONE. NORTHWEST CALIFORNIA COASTAL WATERS... SMALL CRAFT ADVISORY UNTIL 3 PM PDT SATURDAY FOR PZZ450. GALE WARNING UNTIL 3 AM PDT SATURDAY FOR PZZ470. SMALL CRAFT ADVISORY UNTIL 9 AM PDT SATURDAY FOR PZZ475. HAZARDOUS SEAS WARNING UNTIL 9 AM PDT SATURDAY FOR PZZ475. && $$ VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA FOLLOW US ON FACEBOOK AND TWITTER AT: HTTP://WWW.FACEBOOK.COM/NWSEUREKA HTTP://WWW.TWITTER.COM/NWSEUREKA FOR FORECAST ZONE INFORMATION SEE FORECAST ZONE MAP ONLINE: HTTP://WWW.WEATHER.GOV/EUREKA/ZONEMAP.PNG
AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
402 AM PDT FRI MAY 6 2016 .SYNOPSIS... A slow-moving low pressure system will bring a chance of showers and a slight chance of thunderstorms to the region through the weekend. High pressure will rebuild next week bringing mostly clear skies with a warming trend to the area Monday through the middle of next week. Night through morning low clouds and patchy fog are likely for some coastal areas and coastal valley locations through much of next week. && .SHORT TERM...(TDY-SUN) An unseasonably cold upper low was centered just west of Point Conception this morning. This upper low is expected to move slightly to the southeast and remain over Southern California through Saturday before moving east. There will continue be some upper level disturbances rotating around and within the upper low over the forecast area today. 500 mb Temps will be quite cold for this time of year at around -22 degrees C. This will be the main factor to cause the atmosphere to become quite unstable with high lapse rates...especially over the mountains this afternoon and evening. Confidence is high that there will be scattered thunderstorms developing over the mountains this afternoon and evening. Latest model soundings near Lockwood Valley in the Ventura Mtns indicated high CAPE values over 1,100 j/kg, Lifted Index around -6 and plenty of low- mid level moisture to work with. Unlike yesterday, the upper flow will be much weaker due to the proximity of the upper low. Therefore a FLASH FLOOD WATCH has been issued for the Los Angeles, Ventura, Santa Barbara County Mountains, as well as the Antelope Valley and Cuyama Valley valid from noon today through 8 pm this evening. The Precipitable Waters are around .85 inches which is also high for this time of year. People in the flash flood watch areas should keep an eye on the weather today. Once again, it will be difficult to pin-point when and where coast and valley showers will occur today. There will be a slight chance for thunderstorms across the SBA,VTU,LA Valleys and coastal areas as thunderstorms will likely drift to the SE off the mountains. There will be enough instability continuing into this evening to continue the slight chance of thunderstorms. The upper low will continue to swing some moisture over the forecast through Saturday. Showers will be less widespread and not as convective...however there will continue to be slight instability over the mountains on Saturday so a few isolated thunderstorms can`t be ruled out. Winds will remain fairly week out of the north, so there could be a few late afternoon showers drifting into the valleys and coastal areas of LA,VTA and SBA counties. By Sunday...the upper low will be well into the Central Plains, but there will continue to be some lingering moisture across the region, so expect at the least partly cloudy skies. Went ahead and pulled out POPS for Sunday as latest models showed no rain and a much more stable atmosphere. There will likely be a flat cumulus clouds across the mountains and foothills...but cloud cover should not be as widespread across coast and valleys. As far as high temps go...due to the clouds and unsettled weather conditions, temps will be much cooler than normal across the area today thru Sun, with highs ranging from 7 to 16 deg below normal today. High temps will continue to be below normal for this time of year, but trend towards normal by next Tuesday. Hi temps for the cst and vlys will be generally in the 60s today, then warm slightly into the mid 60s to low 70s for Sat, and upper 60s to lower 70s for Sun. .LONG TERM...(MON-THU) EC/GFS continue to be in good agreement Mon thru Thu. Upper level ridging will build off the California coast Monday and become amplified by Tue. This ridge will then shift over California Wednesday and Thursday. Expect dry and warmer conditions through the extended period. Some night and morning marine layer low clouds and fog should affect some coastal and coastal valley areas at times, otherwise clear to partly cloudy skies can be expected across the region for Mon thru Thu. High temps will be around normal by next Tue and Wed, and then warmer than normal for many areas by Thursday, with the warmest vlys reaching the mid 80s. && .AVIATION...06/0010Z. At 0005z at KLAX... there was no marine inversion. Overall... Low to moderate confidence in the 00z tafs. The reduced confidence is primarily due to the hit and miss nature of the showers and thunderstorms in the forecast. Conditions near any thunderstorms will include variable and gusty winds... brief heavy rain... and possible hail. Highest probability of showers and tstms for KLAX, KLGB, KBUR, and KVNY is later this evening through Friday morning. KLAX and KBUR...Low to moderate confidence in the 00z taf. The reduced confidence is primarily due to the hit and miss nature of the showers and thunderstorms in the forecast. Highest probability of showers and thunderstorms for KLAX and KBUR will be 06z-18z, where there is a 60 percent chance of showers and a 20 percent chance of thunderstorms. && .MARINE...06/300 AM. There is a chance of showers across the coastal waters through Saturday night and a slight chance of thunderstorms today, mainly south and east of the Channel Islands. Any storms that develop will be capable of brief heavy downpours, gusty winds, small hail, and dangerous cloud to ground lightning. Winds and seas should remain below advisory criteria through Sunday, except in the vicinity of any thunderstorms that develop. The storm system moves out the of region by late Sunday and no significant wind or sea conditions are expected through the early half of next week. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Flash Flood Watch in effect from noon PDT today through this evening For zones 38-52>54-59. (See LAXFFALOX). PZ...NONE. && $$ PUBLIC...CK AVIATION...Hall MARINE...Hall SYNOPSIS...CK weather.gov/losangeles
Area Forecast Discussion National Weather Service Sacramento CA 402 AM PDT FRI MAY 6 2016 .Synopsis... Unsettled weather will continue into the weekend. Drier and warmer weather is then expected next week. .Short Term Discussion Closed low continues to impact our weather today as the center of the low sits over SoCal today. Models continue to show a vort max rotating around this low into our region this morning. Current radar shows evidence of this as showers from Nevada are now cyclonically moving across the Sierra into our CWA. The HRRR shows a decent slug of moisture stretching from Yosemite up towards Lassen Park and moving westward this morning across interior NorCal between now through late morning with scattered showers continuing for the rest of the day. Models indicating that the atmosphere won`t be as unstable as yesterday, but there is still a slight chance of thunderstorms. Lightning has already been observed this morning over in Nevada. Residents should still be prepared for periods of downpours, gusty winds, lightning, and small hail today even though it may not be as widespread as yesterday. On Saturday, the low tracks farther east in the Great Basin, but wrap around moisture will continue to stream into our CWA continuing the threat of showers and possible thunderstorms into Sunday. By Sunday, though, coverage will diminish with best chances of shower activity persisting over the western Sierra slopes. Monday will start a drier, warmer trend for the work week as high pressure ridging builds over the Eastern Pacific Ocean and impacts the West Coast. Valley highs will return to the low 80s with higher terrain in the 60s and 70s. JBB .EXTENDED DISCUSSION (Tuesday THROUGH Friday) Forecast models are advertising a quick moving upper level disturbance that should slide out of the Pacific Northwest that may clip portions of northern California on Tuesday. This disturbance may bring some isolated sprinkles in the mountains, but no significant precipitation is expected Tuesday or Tuesday night. The main story in the long term forecast period is a return to quiet weather with a pattern of warm and dry weather pushing into California. An upper level ridge of high pressure will move eastward from the Pacific Tuesday night through Wednesday that will bring above normal high temperatures to the valley through the end of next week. && .AVIATION... A stagnant low pressure system positioned over California will bring overcast conditions, light rain showers, and chances for thunderstorms today across the valley. As a result, there will be periods of MVFR ceilings for the terminals north and south of Sacramento. Antecedent moisture from rainfall yesterday could cause some reduced visibilities and ceilings between MVFR and IFR for periods this morning for terminals in Sacramento county. Ceilings and visibilities should improve across the valley Friday evening with a return to VFR conditions for the terminals. && .STO Watches/Warnings/Advisories... None. && $$
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
330 AM PDT FRI MAY 6 2016 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL ALLOW FOR THE CONTINUATION OF UNSETTLED WEATHER THROUGH THE WEEKEND. THIS SYSTEM WILL BRING THE THREAT OF SHOWERS AND THUNDERSTORMS TO MUCH OF THE REGION ALONG WITH COOLER TEMPERATURES. && .DISCUSSION... SHOWERS CONTINUE THIS MORNING ACROSS THE CENTRAL CALIFORNIA INTERIOR AS A RESULT OF THE UPPER LOW SLOWING MOVING ONSHORE TOWARD SOUTHERN CALIFORNIA. WHILE REGIONAL DOPPLER RADARS SHOW A DECREASE IN ACTIVITY THIS MORNING...THE HRRR MESO-SCALE MODEL SHOWS A CONTINUATION OF SHOWERS THROUGH SUNRISE THIS MORNING AS THE FLOW TURNS MORE NORTHERLY. WITH THE SLOW ADVANCEMENT OF THE UPPER LOW ACROSS SOUTHERN CALIFORNIA...THE DISTRICT WILL REMAIN IN A NORTHERLY FLOW PATTERN TODAY WITH ADDITIONAL COLD AIR ADVECTED FROM THE NORTH. CONVECTIVELY SPEAKING...FRIDAY WILL SEE MORE THUNDERSTORMS DURING THE AFTERNOON AS A CONTINUATION OF SOUTHERLY MOISTURE SURGES INTO CENTRAL CALIFORNIA. A CHANGE IN THE WEATHER WILL BE OBSERVED ON SATURDAY AS THE THREAT OF CONVECTION DIMINISHES. WHILE SHOWERS WILL STILL BE OBSERVED DURING THE DAY...THE THREAT OF THUNDERSTORMS WILL BE SMALL. IN ADDITION...THE UPPER LOW WILL BE CLOSER TO THE FOUR CORNERS AREA AS THE DISTRICT WILL THEN BE IN AN OFFSHORE FLOW PATTERN. TYPICALLY...THE FLOW PATTERN IS DRY WITH PRECIP CONFINED TO THE HIGH COUNTRY OF THE SIERRA NEVADA. SUNDAY WILL SEE A CONTINUATION OF THE CHANGE IN THE WEATHER PATTERN AS WE TRANSITION TO A DRY REGIME. CURRENT FORECAST ON TRACK WITH THIS THINKING AS A RIDGE OF HIGH PRESSURE SHIFTS TOWARD THE WEST COAST. WHILE THE TRANSITION TO A RIDGE PATTERN WILL BE SLOW AS ANOTHER WEATHER DISTURBANCE DROPS THROUGH THE PAC-NORTHWEST/INTER-MTN REGION EARLY NEXT WEEK. YET...THE RIDGE PATTERN WILL TAKE HOLD OF THE REGION BY TUESDAY AS TEMPERATURES REACH WELL INTO THE 80S ACROSS THE SAN JOAQUIN VALLEY. ONCE THE RIDGE PATTERN PUSHES INTO THE REGION BY THE MIDDLE OF NEXT WEEK...IT MAY REMAIN OVER THE WEST COAST FOR SEVERAL DAYS. CURRENTLY...WHILE MODELS ARE SHOWING LESS CONFIDENCE IN THE LOWER RANGE PERIODS...THEY DO INDICATE THE DEVELOPMENT OF ANOTHER CLOSED CUT-OFF LOW EXISTING OVER THE EASTERN PACIFIC TOWARD THE END OF NEXT WEEK. AT THE MOMENT... CONFIDENCE IN THE INTRODUCTION OF PRECIP TOWARD THE END OF THE FORECAST PERIOD IS VERY LOW. DUE TO THE NATURE OF THE CUT-OFF LOW ...WILL OPT FOR THE RIDGE SOLUTION IN THE LONG TERM AND WAIT FOR BETTER MODEL CONSENSUS ON HOW TO DEAL WITH THE NEXT DISTURBANCE. && .AVIATION...AREAS OF MVFR AND LOCAL MOUNTAIN OBSCURING IFR OVER THE SOUTHERN SIERRA NEVADA AND TEHACHAPI MOUNTAINS THRU 12Z SATURDAY. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE THROUGHOUT THE CENTRAL CA INTERIOR THROUGH 12Z SATURDAY. OTHERWISE...VFR CONDITIONS WILL PREVAIL DURING THE NEXT 24 HOURS. && .AIR QUALITY ISSUES... NONE. && .CERTAINTY... THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH. THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM. CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT WWW.WEATHER.GOV/HNX/CERTAINTY.PHP FOR ADDITIONAL INFORMATION AN/OR TO PROVIDE FEEDBACK. && .HNX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ PUBLIC...MOLINA AVN/FW...JDB SYNOPSIS...MOLINA WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
441 AM MDT FRI MAY 6 2016 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 430 AM MDT FRI MAY 6 2016 THE DEEPENING TROUGH/CLOSED LOW TRACKING SLOWLY E-SEWRD ACROSS SOUTHERN CALIF IS BEGINNING TO EXERT ITS DOMINANCE ON FLOW AT ALL LEVELS AND WX AS FAR EAST AS THE SRN AND CNTRL ROCKIES. DEEP S-SWLY FLOW ON THE FRONT SIDE OF THIS TROUGH CONTINUES TO DIRECT MID AND HIGH-LEVEL MOISTURE UP INTO THE AREA AND LATER TODAY A SPOKE OF MID- LEVEL ENERGY AND SHEAR WHICH THE RAP AND OTHER MODELS INDICATE PASSING OVER NRN NEW MEXICO AT THIS TIME. EVEN WITH VARYING AMOUNTS OF HIGH CLOUDINESS THIS MORNING STRONG DIABATIC HEATING SHOULD MANAGE TO GENERATE 8-9C/KM BNDRY LAYER LAPSE RATES AND SFC BASED 600- 1200 J/KG CAPES ON THE PLAINS BY MIDDAY. WHILE THE WELL MIXED BOUNDARY LAYER APPEAR LACKING OF MOISTURE...MODELS INDICATE A GRADUAL INCREASE IN MID-LEVEL MOISTURE WITH INCREASING SELY MID- LEVEL FLOW IN ADVANCE OF THE SHORTWAVE DISTURBANCE SWINGING UP FROM SERN COLORADO. WHILE CONVECTIVE CLOUDS WILL BE ON THE INCREASE THIS AFTERNOON...MODELS DO NOT INDICATE MUCH IN THE WAY OF QPF ON THE PLAINS TODAY. INVERTED-V MODEL SOUNDINGS INDICATE A FAVORABLE SUB- CLOUD ENVIRONMENT FOR MICROBURST FORMATION THIS AFTERNOON EVEN AS MEAN LAYER PW VALUES CREEP UPWARD PRIOR TO PASSAGE OF THE U/A DISTURBANCE TIMED TO OCCUR AROUND 00Z IN THE DENVER AREA. AFTER 00Z/SAT...THE MICROBURST THREAT SHOULD QUICKLY DIMINISH FROM SOUTH TO NORTH WITH INFLUX OF DRIER MIX-LEVEL AIR BEHIND THE SHORTWAVE. THIS DRYING IS FORECAST TO CONTINUE EVEN NEAR THE GROUND OVERNIGHT AS MODELS SHOW A WELL PRONOUNCED DRY SLOT ROTATING UP FROM NEW MEXICO. FOR THE HIGH COUNTRY...ODDS LOOK BETTER FOR MEASURABLE PRECIP TODAY...BEGINNING AS EARLY AS LATE THIS MORNING. GREATER MOISTURE... BETTER SYNOPTIC SCALE LIFT..INSTABILITY AND OROGRAPHICS SHOULD PROVE ADEQUATE FOR SHOWER AND T-STORM FORMATION. SHOWERS AND T-STORM MOTIONS WILL PRIMARILY SOUTH-TO-NORTH TODAY. SO THERE`S LITTLE CHANCE THAT THE PLAINS WILL SEE MUCH IF ANY OF THIS HIGH COUNTRY CONVECTION. GUSTY WINDS AND SHORT PERIODS OF LIGHT TO MODERATE RAINFALL POSSIBLE THIS AFTERNOON THRU EARLY EVENING FROM THE FRONT RANGE WESTWARD. I PUT THE CHANCE OF MEASURABLE PRECIP IN THE HIGH COUNTRY AT 30-50 PCT...WITH AS FEW POCKETS OF 60 PCT OVER THE HIGHER PEAKS AND RIDGES ROUGHLY NORTH OF I-70 LATE. LIKE THE PLAINS...THE CHANCE OF PRECIP IN THE HIGH COUNTRY SHOULD STEADILY DECREASE WITH CLOUD COVER OVERNIGHT WITH AN INFLUX OF DRIER AIR FROM THE SOUTH AHEAD OF THE UPPER TROUGH. TEMPERATURES TODAY WILL BE QUITE WARM AGAIN BUT NOT QUITE RECORD TERRITORY. RECORD HIGH AT DENVER IS 86. SHOULD SEE LOW 80S IN THE METRO AREA AND LOW TO MID 80S ACROSS THE PLAINS. HIGH COUNTRY WILL ALSO BE UNSEASONABLY WARM TODAY WITH HIGHS IN THE UPPER 50S AND 60S. TONIGHT...TEMPERATURE WILL REMAIN QUITE MILD WITH MID 40S/ LOWER 50S ON THE PLAINS AND MOSTLY 30S IN THE HIGH COUNTRY. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 430 AM MDT FRI MAY 6 2016 LARGE UPPER LEVEL LOW WILL BE OVER THE GREAT BASIN SATURDAY. A STRONG WAVE EMBEDDED IN THE SOUTHWEST FLOW ALOFT WILL MOVE ACROSS EASTERN COLORADO SATURDAY AND EVENTUALLY BECOME THE NEW CENTER OF THE UPPER LEVEL LOW SOMEWHERE OVER WYOMING OR NORTHEAST COLORADO. FOR SATURDAY...A SURFACE LOW WILL BE OVER NORTHEAST COLORADO WITH A BOUNDARY DRAPED ACROSS THE AREA. EASTERLY WINDS NORTH OF IT WILL PUMP MOISTURE INTO THE AREA. SURFACE BASED CAPES WILL BE UP TO 2000 J/KG. THIS COMBINED WITH GOOD SHEAR IS EXPECTED TO PRODUCE SEVERE THUNDERSTORMS WITH LARGE HAIL...STRONG WINDS AND POSSIBLY A FEW TORNADOS. STILL SOME UNCERTAINTY WHERE THIS BOUNDARY WILL SET UP. LATEST MODEL RUNS ARE LITTLE MORE NORTH AND HAS MOST OF THE CONVECTION NORTH OF A LINE FROM FORT COLLING TO AKRON. STILL WOULDN`T BE SURPRISED IF THIS BOUNDARY ENDS UP FARTHER SOUTH THAN THE MODELS ARE FORECASTING. ON SUNDAY...THE ECMWF HAS THE CENTER OF THE UPPER LEVEL LOW OVER NORTHEAST COLORADO WHILE THE GFS SHOWS IT OVER WYOMING. NO STRONG FEELING WHICH ONE IS RIGHT. IT WILL BE COOL AND IF THE LOW FORMS OVER COLORADO...EXPECT MORE PRECIPITATION ACROSS THE AREA. NORTHWEST FLOW WILL PREVAIL MONDAY AS THE UPPER LEVEL LOW WEAKENS EAST OF COLORADO. STILL SHOULD BE ENOUGH MOISTURE AND INSTABILITY TO TRIGGER SCATTERED/ISOLATED SHOWERS AND STORMS. ANOTHER UPPER LEVEL LOW WILL MOVE INTO THE NORTHERN ROCKIES MONDAY. THIS LOW IS EXPECTED TO DIG SOUTH INTO WYOMING TUESDAY. ISOLATED TO SCATTERED CONVECTION WILL AGAIN BE POSSIBLE. THIS LOW IS EXPECTED TO MOVE EAST OF THE AREA WEDNESDAY AND THURSDAY. COULD SEE A FEW SHOWERS AND STORMS WEDNESDAY...BUT DRIER AND WARMER CONDITIONS SHOULD PREVAIL THURSDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 430 AM MDT FRI MAY 6 2016 VFR CONDITIONS ON TAP NEXT 24 HOURS FOR THE DENVER AREA. ONLY CONCERN WILL BE THE HIGH BASED MOSTLY DRY T-STORMS THAT ARE EXPECTED TO TRACK NORTH-NORTHWEST ACROSS THE METRO AREA BETWEEN 2 PM MDT-7PM MDT TODAY. ASIDE FROM A STRAY LIGHTNING STRIKE... THESE ISOLATED TO WIDELY SCATTERED CELLS MAY ALSO PRODUCE MICROBURST WINDS TO 40KTS. THREAT OF THESE WINDS SHOULD END ERLY THIS EVENING WITH DRIER AIR FEEDING UP FROM THE SOUTH. WINDS TODAY GENERALLY SOUTH-SOUTHEASTERLY AT 7-15KTS..WITH STRONGER GUSTY AND ERRATIC WINDS UNDER AND NEAR PASSING SHOWERS. OVERNIGHT...WINDS IN THE DENVER AREA TO BECOME A BIT STRONGER FROM THE SOUTHEAST AT 10-20KTS...WITH HIGHER GUSTS POSSIBLE IN THE EVENING AT KAPA AND KDEN. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BAKER LONG TERM...MEIER AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
436 AM MDT FRI MAY 6 2016 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 436 AM MDT FRI MAY 6 2016 LARGE CLOSED LOW MOVING ONSHORE THE WESTERN US TODAY WILL SLOWLY MOVE EASTWARD OVER THE NEXT FEW DAYS. TODAY...STRONG LARGE SCALE ASCENT WILL BE DRIVING THUNDERSTORM DEVELOPMENT FROM SOUTH TO NORTH. ALREADY THIS MORNING THE CLOUD TOPS HAVE BEEN INCREASING FAIRLY DRAMATICALLY FROM NORTHERN ARIZONA INTO UTAH. THIS AREA OF ENHANCING PRECIPITATION WILL SHIFT EAST TODAY AND BRING SCATTERED SHOWERS AND THUNDERSTORMS TO EASTERN UTAH AND WESTERN COLORADO FOR MUCH OF TODAY. SOME STORMS MAY NEAR OR POTENTIALLY EXCEED SEVERE THUNDERSTORM CRITERIA TODAY...WITH WIND BEING THE LARGEST THREAT. WIND GUSTS MAY EXCEED 58 MPH IN THE STRONGEST STORMS AND HAIL UP TO ONE INCH IS POSSIBLE...THOUGH LESS LIKELY THAN REACHING THE STRONG WIND GUSTS. THE RAP FORECAST MODEL INDICATES DAYTIME HEATING WILL OVERCOME CONVECTIVE INHIBITION ACROSS NE UTAH AROUND NOON AND ACROSS WESTERN COLORADO SHORTLY THEREAFTER. FORECAST CAPE VALUES EXCEED 1000 J/KG THIS AFTERNOON...INDICATING A PEAK OF CONVECTIVE ACTIVITY AROUND 4 TO 8PM ACROSS NE UTAH AND NW COLORADO. THERE WILL BE A LOT OF VIRGA AROUND TODAY WHICH WILL HELP TO KEEP CONDITIONS BREEZY THROUGHOUT THE DAY WITH OR WITHOUT RAIN NEARBY. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 436 AM MDT FRI MAY 6 2016 THE DETAILS OF THIS SLOW MOVING SYSTEM CONTINUE TO EVOLVE. IT LOOKS LIKE THERE WILL BE AT LEAST A COUPLE OF ROBUST CIRCULATIONS THAT WILL TRACK ACROSS THE AREA SAT AND SUN. THROUGH THE WEEKEND...LOOK FOR ENHANCED SHOWERS AND THUNDERSTORMS AS EACH CIRCULATION PASSES. POPS GENERALLY SHOW A BROAD-BRUSHED FORECAST WITH CHANCE TO LIKELY POPS...MAINLY IN THE MOUNTAINS. AFTERNOONS/EARLY EVENINGS WILL SHOW AN UPTICK IN CONVECTION INCLUDING THUNDERSTORMS DUE TO THE DIURNAL ASSIST. SNOW LEVELS WILL REMAIN HIGH AS THIS SYSTEM IS QUITE MILD. ACCUMULATING SNOW WILL GENERALLY BE AT OR ABOVE 10K-11K FEET. BUT CONVECTION WILL CERTAINLY DRIVE SNOW...GRAUPEL OR SNOW PELLETS LOWER AT TIMES. DID BUMP UP POPS OVER THE NEXT FEW DAYS DURING TIME PERIODS WHERE I WAS MORE CONFIDENT IN PRECIPITATION OCCURRING...WITH THE BIGGEST INCREASE LATE SUNDAY NIGHT. AVAILABLE MOISTURE SIGNIFICANTLY INCREASES LATE SUNDAY AND MONDAY AND THE CLOSED LOW WRAPS STRONG ENERGY COUNTERCLOCKWISE INTO THE WESTERN SLOPE OF COLORADO. EXACT SET-UP LOCATION OF THIS WRAP-AROUND WILL HAVE TO BE DIAGNOSED IN LATER FORECASTS...BUT CONFIDENCE IS THERE FOR AN UPTICK IN PRECIPITATION COVERAGE SUNDAY NIGHT INTO EARLY MONDAY. WITH LESS CONFIDENCE...MODELS INDICATE ANOTHER SEPARATE DISTURBANCE WILL BRUSH THE NORTH DURING THE TUE- WED TIME FRAME AS A TROUGH PASSES ACROSS THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS. THE IMPACTS FROM THIS NEXT SYSTEM LOOK PRETTY LOW AT THIS TIME. A COOLING TREND WILL CONTINUE THROUGH SUNDAY. THE TREND WILL THEN REVERSE FOR A SLOW WARMUP THROUGH THE NEW WORK WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 436 AM MDT FRI MAY 6 2016 THE MORNING IS ALREADY STARTING OFF EXCITING WITH STORMS HAVING INITIATED BEFORE 10Z. INITIATION OF STORMS WILL CONTINUE AS LARGE SCALE ASCENT DRAMATICALLY INCREASES TODAY. GUSTY WINDS TO 60 MPH WILL BE THE LARGEST THREAT TODAY WITH THUNDERSTORMS...BUT THIS IS NOT EXPECTED UNTIL AFTER 18Z AND WILL BE VERY ISOLATED IN NATURE IF AT ALL. CONDITIONS WILL STAY GENERALLY BREEZY TODAY. HEAVY PRECIPITATION IS NOT EXPECTED AT THIS TIME...SO CIGS AND VIS WILL REMAIN VFR THROUGH MOST OF THE DAY. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...JAM LONG TERM...EH/JAM AVIATION...JAM
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1134 AM EDT FRI MAY 6 2016 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE INTO OUR AREA FROM THE SOUTHEAST LATER TODAY, THEN LINGER THROUGH SATURDAY BEFORE DISSIPATING. A COLD FRONT WILL MOVE THROUGH SUNDAY MORNING, FOLLOWING BY HIGH PRESSURE SUNDAY NIGHT INTO MONDAY BEFORE MOVING OFFSHORE. A WARM FRONT LIFTS NORTH ACROSS OUR AREA DURING TUESDAY, THEN STALLS IN OUR AREA WEDNESDAY INTO THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SOME HEAVIER SHOWERS HAVE BEEN TRAVERSING THE REGION THIS MORNING WITH SCATTERED SHOWERS CONTINUING ACROSS THE AREA. EXPECT THE HEAVIER RAIN TO CONTINUE TO PUSH TO THE WEST-SOUTHWEST AND OUT OF THE AREA THIS MORNING. LIGHT TO MODERATE RAIN SHOWERS WILL CONTINUE THROUGH THE REST OF THE DAY WITH SOME TAPERING OFF EXPECTED FROM EAST TO WEST LATER IN THE DAY. SPC HAS EXPANDED THE AREA OF GENERAL THUNDER SO HAVE INCLUDED A SLIGHT RISK THROUGH THIS AFTERNOON ACROSS THE ENTIRE AREA. CONSIDERABLE INSTABILITY ALOFT SUGGEST POTENTIAL FOR ISOLATED THUNDER/ASSOCIATED SMALL HAIL WITH VERY STEEP MID LVL LAPSE RATES AND LOW WBZ NEAR 6000 FT. NOT SURE WHAT WILL TRIGGER THE THUNDER EXCEPT SFC CONVERGENCE WITH THE LOW COMING ASHORE AND PERHAPS SOME AFTERNOON SFC HEATING NEAR THE APPROACHING LOW OVER DE. TEMPS MAY BE SEVERAL DEGREES COLDER THAN YDY I95 NWWD. A GUSTY NE WIND FOR A TIME THIS MORNING NEAR 20 MPH EXCEPT GUSTS MIDDAY AND EARLY AFTERNOON MONMOUTH AND OCEAN COUNTIES MAY APPROACH 35 MPH (SEE HRRR GUSTS AS A BAND OF STRONGER WIND WELL NORTH OF THE LOW CENTER SHIFTS WESTWARD WITH LOW ALONG THE S SHORE OF LI). && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... HAVE UNCERTAINTY REGARDING TIMING OF ANY SHOWERS AND ANY LEFTOVER ISOLATED EVENING TSTMS (SE PA/S NJ). CONFIDENCE ON WHAT OCCURS AND WHERE, IS BELOW AVERAGE. IN PART THIS IS DUE TO RECENT LOSS OF CONFIDENCE IN GFS QPF FCSTS. NE WIND DIMINISHING THIS EVENING AND BECOMING LIGHT SOUTHERLY ON THE DELMARVA, POSSIBLY EVEN TO I95. FOG MAY BECOME A PROBLEM TONIGHT WITH A LIGHT WIND IN THE MIDST OF VERTICALLY STACKED MOIST LOW PRESSURE SYSTEM. FCST WAS A 50 50 BLEND OF THE 00Z/6 GFS/NAM MOS. && .LONG TERM /SATURDAY THROUGH THURSDAY/... THE SYNOPTIC SETUP IS COMPRISED OF AN INITIAL CLOSED LOW CENTERED OVER OUR AREA SATURDAY, HOWEVER THIS FEATURE OPENS UP DURING SATURDAY AS IT SHIFTS EASTWARD. THIS OCCURS AS A STRONG SHORT WAVE TROUGH DIVES SOUTHEASTWARD ACROSS THE GREAT LAKES SATURDAY AND INTO THE NORTHEAST SATURDAY NIGHT AND SUNDAY. THE NEW TROUGH AMPLIFIES ACROSS THE NORTHEAST SUNDAY BEFORE GRADUALLY LIFTING OUT MONDAY. A WEAK RIDGE THEN ARRIVES FOR EARLY NEXT WEEK WITH A SURFACE WARM FRONT ALSO MOVING THROUGH. THE WARM FRONT HOWEVER MAY END UP STALLING IN OUR VICINITY WEDNESDAY AND THURSDAY AS ENERGY SHEARS EASTWARD ALONG IT. GIVEN THE PATTERN CHANGE, MUCH WARMER AIR IS EXPECTED TO ARRIVE NEXT WEEK WITH THIS CHANGE STARTING OVER THE WEEKEND ESPECIALLY DURING SUNDAY. THE EXTENT OF THE WARMING THOUGH NEXT WEEK WILL DEPEND ON THE PLACEMENT OF THE FRONTAL BOUNDARY AS IT MAY MEANDER ACROSS OUR CWA AND ALSO PRECIPITATION CHCS. WE USED A MODEL BLEND APPROACH FOR SATURDAY THROUGH SUNDAY NIGHT, THEN BLENDED IN THE 00Z WPC GUIDANCE THEREAFTER. SOME ADJUSTMENTS WERE THEN MADE FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES. FOR SATURDAY AND SUNDAY...THIS TIME FRAME BEGINS WITH A CLOSED LOW RIGHT OVER OUR AREA SATURDAY MORNING, HOWEVER THIS FEATURE WILL OPEN UP AND SHIFT EASTWARD DURING THE COURSE OF THE DAY. THIS WILL BE DUE TO A KICKER SHORT WAVE TROUGH AMPLIFYING ACROSS THE GREAT LAKES REGION. A CORE OF -20C TO -24C AIR AT 500 MB IS OVER OUR AREA SATURDAY MORNING, HOWEVER THIS MODIFIES THROUGH THE DAY AS THE TROUGH OPENS UP AND SHIFTS TO OUR EAST. THE PRESENCE OF COLD AIR ALOFT COMBINED WITH SOME LIFT FROM THE CLOSED LOW SHOULD RESULT IN MAINLY SCATTERED SHOWERS SATURDAY ESPECIALLY INLAND. THE FLOW IS LIGHT UNDER THE CLOSED LOW THEREFORE SHOWERS SHOULD BE SLOW MOVERS. SINCE THE AIRMASS IS WARMING DURING THE COURSE OF THE DAY, THIS MAY MITIGATE THE INSTABILITY POTENTIAL. IT APPEARS ANY INSTABILITY IS MARGINAL AND THEREFORE THUNDER WAS NOT ADDED FOR SATURDAY ATTM. AS WE LOSE THE CONTINUOUS ONSHORE FLOW COMPONENT AND THE TROUGH ALOFT WEAKENING THROUGH SATURDAY, THERE SHOULD BE AT LEAST SOME BREAKS OF SUNSHINE. AN AMPLIFYING TROUGH FROM THE GREAT LAKES THEN STARTS TO NEAR OUR AREA TOWARD DAYBREAK SUNDAY. LOW PRESSURE TRACKING TO OUR NORTH WILL PULL A COLD FRONT INTO OUR AREA LATE SATURDAY NIGHT AND THIS FRONT MAY MOVE IN A BIT FASTER. THERE APPEARS TO BE A PLUME OF DEEPER MOISTURE IN COMBINATION WITH FORCING FOR ASCENT TO DRIVE SOME SHOWERS /PERHAPS A BAND OF SHOWERS/ ACROSS MUCH OF OUR AREA. THE STRONGEST FORCING MAY GLANCE OUR NORTHERN AREAS AND THEREFORE THE HIGHEST POPS WERE PLACED THERE LATER AT NIGHT. ANY SHOWERS SHOULD QUICKLY SHIFT OFFSHORE SUNDAY MORNING AS THE COLD FRONT ALSO EXITS, THEN DRIER AIR AND BETTER MIXING WILL PROMOTE SUNSHINE FINALLY RETURNING FOR THE AFTERNOON. IT WILL BE A BIT BREEZY THOUGH SUNDAY IN THE WAKE OF THE COLD FRONT AS LOW-LEVEL LAPSE RATES STEEPEN AND THE PRESSURE GRADIENT TIGHTENS. WE WENT A BIT WARMER THAN MOS FOR SUNDAY ESPECIALLY FOR THE COASTAL PLAIN GIVEN DOWNSLOPING FLOW. HIGH PRESSURE THEN STARTS TO ARRIVE SUNDAY NIGHT ALLOWING THE WINDS TO DIMINISH. FOR MONDAY AND TUESDAY...SOME WEAK RIDGING ARRIVES DURING MONDAY, ALLOWING SURFACE HIGH PRESSURE TO BE OVER OUR CWA TO START BUT IT LOOKS TO SHIFT OFFSHORE LATER MONDAY. THIS WILL ALLOW A SOUTHERLY FLOW TO BECOME BETTER ESTABLISHED AND WITH DOWNSTREAM WAA INCREASING, A WARMER TIME FRAME IS EXPECTED. THE WAA WILL BE USHERED IN VIA A WARM FRONT AS IT CROSSES THE AREA DURING TUESDAY, AND THERE COULD BE ENOUGH LIFT TO PRODUCE SOME SHOWERS OR A THUNDERSTORM MAINLY TUESDAY AFTERNOON AND NIGHT. THE FORECAST CHALLENGE IS THAT THIS FRONT MAY THEN STALL IN OUR AREA AS ENERGY INITIALLY SHEARS EASTWARD ALONG IT. THIS SHEARING ENERGY COULD PRODUCE SOME CONVECTION. FOR WEDNESDAY AND THURSDAY...THE FORECAST CHALLENGE IS WITH THE FRONTAL ZONE AS IT LOOKS TO BE DRAPED ACROSS OUR AREA, HOWEVER A TROUGH AMPLIFYING ACROSS NEW ENGLAND WEDNESDAY MAY PUSH THE FRONT FARTHER SOUTHWARD. THIS SOUTHWARD PUSH COULD BE ENHANCED AS HIGH PRESSURE MAY BUILD DOWN SOME FROM NORTHERN NEW ENGLAND. A TROUGH IN THE MIDWEST HOWEVER PUSHES SURFACE LOW PRESSURE UP THE OHIO VALLEY WEDNESDAY NIGHT INTO THURSDAY, WITH DOWNSTREAM WAA AND SOUTHERLY FLOW ALLOWING THE BOUNDARY TO START LIFTING NORTHWARD SOME AS A WARM FRONT. THIS TIME FRAME SHOULD BE ON THE WARMER SIDE, HOWEVER THIS WILL ULTIMATELY DEPEND ON THE POSITIONING OF THE FRONTAL BOUNDARY AND ANY CONVECTION THAT OCCURS. GIVEN THE UNCERTAINTY, WE BLENDED THE 00Z WPC GUIDANCE IN WITH CONTINUITY AND THEN MADE SOME TWEAKS. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...CIGS GENERALLY VARIABLE 600-1600 FT VSBY 1-4 MI IN SHOWERY RAINS DURING THE MORNING WITH POSSIBLE IMPROVING CONDITIONS DURING THE AFTERNOON. ISOLATED TSTM POSSIBLE DURING THE MORNING KACY/KMIV AND THEN DURING THE AFTN ELSEWHERE. TSTMS NOT IN TAF DUE TO LOW CONFIDENCE AND ISOLATED NATURE. NE WIND...GUSTS 15-23 KT FOR A TIME LATER THIS MORNING-MIDDAY. TONIGHT... MVFR/IFR CONDS IN ST/FOG, POSSIBLE CLUSTERS OF SHOWERS. DIMINISHING NE WIND THIS EVENING NEAR AND N OF I78. OTHERWISE LIGHT WIND TRENDING SOUTH. OUTLOOK... SATURDAY...MVFR/IFR CEILINGS IN THE MORNING SHOULD IMPROVE TO VFR IN THE AFTERNOON. MAINLY SCATTERED SHOWERS ARE ANTICIPATED WHICH CAN LOCALLY REDUCE THE VISIBILITY FOR A TIME, THEN A BAND OF SHOWERS ARRIVES LATE AT NIGHT WITH A COLD FRONT. SOUTHEASTERLY WINDS MAINLY LESS THAN 10 KNOTS, BECOMING SOUTHWEST AT NIGHT. SUNDAY...BRIEF MVFR CONDITIONS IN THE MORNING WITH SOME SHOWERS AS A COLD FRONT MOVES THROUGH, OTHERWISE VFR. WEST TO NORTHWEST WINDS INCREASE TO 12-18 KNOTS WITH GUSTS TO 25 KNOTS, THEN DIMINISH AT NIGHT. MONDAY AND TUESDAY...VFR, THEN POSSIBLY SOME MVFR DURING TUESDAY WITH A CHANCE OF SHOWERS AS A WARM FRONT MOVES THROUGH. WESTERLY WINDS AROUND 10 KNOTS MONDAY, BECOMING LIGHT AT NIGHT THEN SHIFTING TO SOUTHERLY TUESDAY. && .MARINE... WE HAVE UPGRADED THE SMALL CRAFT ADVISORY ON OUR NORTHERN TWO OCEAN ZONES TO A GALE WARNING THROUGH THIS AFTERNOON. GALE FORCE GUSTS ARE EXPECTED TO OCCUR OVER THE NEXT SEVERAL HOURS AND THEN SHOULD TAPER OFF AS WE HEAD INTO THE LATE AFTERNOON AND EVENING. SCA CONTINUES OCEAN WATERS THROUGH TONIGHT, ESPECIALLY DUE TO SEAS. FOG MAY BECOME A MARINE HAZARD LATER THIS FRIDAY NIGHT. OUTLOOK... SATURDAY...THE WINDS ARE ANTICIPATED TO BE LIGHT AS A CLOSED LOW INITIALLY OVERHEAD WEAKENS AND THEN SHIFTS EASTWARD. THE SEAS MAY BE RIGHT AT 5 FEET TO START ESPECIALLY ACROSS THE NORTHERN WATERS BUT OVERALL THE CONDITIONS SHOULD BE TRENDING BELOW ADVISORY CRITERIA. THEREFORE WE DID NOT EXTEND THE ADVISORY ATTM. SUNDAY...WEST TO NORTHWEST WINDS TURN GUSTY TO AROUND 20 KNOTS WITH SEAS AT OR BELOW 4 FEET. IT IS POSSIBLE WINDS GUST TO 25 KNOTS NEARSHORE, HOWEVER OVERALL CONDITIONS ARE ANTICIPATED TO BE BELOW ADVISORY CRITERIA. MONDAY AND TUESDAY...SUB-ADVISORY CONDITIONS ARE ANTICIPATED DESPITE SOME INCREASE IN A SOUTHERLY WIND MONDAY AND THEN AGAIN LATER TUESDAY. && .TIDES/COASTAL FLOODING... PLEASE SEE THE HAZARD CFW STATEMENT FOR THE PARTICULARS RELATING TO EACH AREA. PHL: TIDAL DE ADVY EXPIRED BUT MAY NEED A NEW ONE TO BE ISSUED THIS AFTERNOON FOR THE EARLY SATURDAY MORNING HIGH TIDE CYCLE. CONFIDENCE IN EXCEEDING THE ADVY THRESHOLD WAS NOT QUITE CATEGORICAL ON THIS SHIFT. REEDY POINT UPPER DE BAY, LOWER TIDAL DE LINKED: REISSUED FOR LATE THIS EVENING, SINCE CONFIDENCE IS CATEGORICAL THAT IT WILL REOCCUR, ESPECIALLY BECAUSE THE FUNNELED ENE FLOW THIS MORNING TURNS LIGHT SOUTH THIS EVENING. NJ/DE ATLC COASTS: NO CHANGE IN THE PREVIOUS WARNING. THE TIDAL SURGE IS EXPECTED TO STAY AROUND 1 TO 1.5 FEET TODAY IN THE CONTINUING NORTHEASTERLY FLOW. THE THURSDAY EVENING HIGH TIDE SAW MANY OBSERVING SITES EITHER JUST REACH OR FALL JUST SHY OF MODERATE FLOODING THRESHOLDS. WE ARE FORECASTING MINOR TIDAL FLOODING AROUND THIS MORNING`S HIGH TIDE AND MODERATE FLOODING AROUND THIS FRIDAY EVENING`S HIGH TIDE. RATHER THAN CARRY MULTIPLE HEADLINES, WE CONTINUED WITH THE COASTAL FLOOD WARNING TO COVER BOTH HIGH TIDE CYCLES. MINOR TIDAL FLOODING MAY LINGER WITH THE HIGH TIDE CYCLES ON SATURDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...COASTAL FLOOD WARNING UNTIL 1 AM EDT SATURDAY FOR NJZ012>014- 020>027. COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 2 AM EDT SATURDAY FOR NJZ016. DE...COASTAL FLOOD WARNING UNTIL 1 AM EDT SATURDAY FOR DEZ002>004. COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 2 AM EDT SATURDAY FOR DEZ001. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ452>455. GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR ANZ450-451. && $$ SYNOPSIS...GORSE NEAR TERM...DRAG/MEOLA SHORT TERM...DRAG LONG TERM...GORSE AVIATION...DRAG/GORSE MARINE...DRAG/GORSE/MEOLA TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
953 AM EDT FRI MAY 6 2016 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE INTO OUR AREA FROM THE SOUTHEAST LATER TODAY, THEN LINGER THROUGH SATURDAY BEFORE DISSIPATING. A COLD FRONT WILL MOVE THROUGH SUNDAY MORNING, FOLLOWING BY HIGH PRESSURE SUNDAY NIGHT INTO MONDAY BEFORE MOVING OFFSHORE. A WARM FRONT LIFTS NORTH ACROSS OUR AREA DURING TUESDAY, THEN STALLS IN OUR AREA WEDNESDAY INTO THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SOME HEAVIER SHOWERS HAVE BEEN TRAVERSING THE REGION THIS MORNING WITH SCATTERED SHOWERS CONTINUING ACROSS THE AREA. EXPECT THE HEAVIER RAIN TO CONTINUE TO PUSH TO THE WEST-SOUTHWEST AND OUT OF THE AREA THIS MORNING. LIGHT TO MODERATE RAIN SHOWERS WILL CONTINUE THROUGH THE REST OF THE DAY WITH SOME TAPERING OFF EXPECTED FROM EAST TO WEST LATER IN THE DAY. SPC HAS EXPANDED THE AREA OF GENERAL THUNDER SO HAVE INCLUDED A SLIGHT RISK THROUGH THIS AFTERNOON ACROSS THE ENTIRE AREA. CONSIDERABLE INSTABILITY ALOFT SUGGEST POTENTIAL FOR ISOLATED THUNDER/ASSOCIATED SMALL HAIL WITH VERY STEEP MID LVL LAPSE RATES AND LOW WBZ NEAR 6000 FT. NOT SURE WHAT WILL TRIGGER THE THUNDER EXCEPT SFC CONVERGENCE WITH THE LOW COMING ASHORE AND PERHAPS SOME AFTERNOON SFC HEATING NEAR THE APPROACHING LOW OVER DE. TEMPS MAY BE SEVERAL DEGREES COLDER THAN YDY I95 NWWD. A GUSTY NE WIND FOR A TIME THIS MORNING NEAR 20 MPH EXCEPT GUSTS MIDDAY AND EARLY AFTERNOON MONMOUTH AND OCEAN COUNTIES MAY APPROACH 35 MPH (SEE HRRR GUSTS AS A BAND OF STRONGER WIND WELL NORTH OF THE LOW CENTER SHIFTS WESTWARD WITH LOW ALONG THE S SHORE OF LI). && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... HAVE UNCERTAINTY REGARDING TIMING OF ANY SHOWERS AND ANY LEFTOVER ISOLATED EVENING TSTMS (SE PA/S NJ). CONFIDENCE ON WHAT OCCURS AND WHERE, IS BELOW AVERAGE. IN PART THIS IS DUE TO RECENT LOSS OF CONFIDENCE IN GFS QPF FCSTS. NE WIND DIMINISHING THIS EVENING AND BECOMING LIGHT SOUTHERLY ON THE DELMARVA, POSSIBLY EVEN TO I95. FOG MAY BECOME A PROBLEM TONIGHT WITH A LIGHT WIND IN THE MIDST OF VERTICALLY STACKED MOIST LOW PRESSURE SYSTEM. FCST WAS A 50 50 BLEND OF THE 00Z/6 GFS/NAM MOS. && .LONG TERM /SATURDAY THROUGH THURSDAY/... THE SYNOPTIC SETUP IS COMPRISED OF AN INITIAL CLOSED LOW CENTERED OVER OUR AREA SATURDAY, HOWEVER THIS FEATURE OPENS UP DURING SATURDAY AS IT SHIFTS EASTWARD. THIS OCCURS AS A STRONG SHORT WAVE TROUGH DIVES SOUTHEASTWARD ACROSS THE GREAT LAKES SATURDAY AND INTO THE NORTHEAST SATURDAY NIGHT AND SUNDAY. THE NEW TROUGH AMPLIFIES ACROSS THE NORTHEAST SUNDAY BEFORE GRADUALLY LIFTING OUT MONDAY. A WEAK RIDGE THEN ARRIVES FOR EARLY NEXT WEEK WITH A SURFACE WARM FRONT ALSO MOVING THROUGH. THE WARM FRONT HOWEVER MAY END UP STALLING IN OUR VICINITY WEDNESDAY AND THURSDAY AS ENERGY SHEARS EASTWARD ALONG IT. GIVEN THE PATTERN CHANGE, MUCH WARMER AIR IS EXPECTED TO ARRIVE NEXT WEEK WITH THIS CHANGE STARTING OVER THE WEEKEND ESPECIALLY DURING SUNDAY. THE EXTENT OF THE WARMING THOUGH NEXT WEEK WILL DEPEND ON THE PLACEMENT OF THE FRONTAL BOUNDARY AS IT MAY MEANDER ACROSS OUR CWA AND ALSO PRECIPITATION CHCS. WE USED A MODEL BLEND APPROACH FOR SATURDAY THROUGH SUNDAY NIGHT, THEN BLENDED IN THE 00Z WPC GUIDANCE THEREAFTER. SOME ADJUSTMENTS WERE THEN MADE FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES. FOR SATURDAY AND SUNDAY...THIS TIME FRAME BEGINS WITH A CLOSED LOW RIGHT OVER OUR AREA SATURDAY MORNING, HOWEVER THIS FEATURE WILL OPEN UP AND SHIFT EASTWARD DURING THE COURSE OF THE DAY. THIS WILL BE DUE TO A KICKER SHORT WAVE TROUGH AMPLIFYING ACROSS THE GREAT LAKES REGION. A CORE OF -20C TO -24C AIR AT 500 MB IS OVER OUR AREA SATURDAY MORNING, HOWEVER THIS MODIFIES THROUGH THE DAY AS THE TROUGH OPENS UP AND SHIFTS TO OUR EAST. THE PRESENCE OF COLD AIR ALOFT COMBINED WITH SOME LIFT FROM THE CLOSED LOW SHOULD RESULT IN MAINLY SCATTERED SHOWERS SATURDAY ESPECIALLY INLAND. THE FLOW IS LIGHT UNDER THE CLOSED LOW THEREFORE SHOWERS SHOULD BE SLOW MOVERS. SINCE THE AIRMASS IS WARMING DURING THE COURSE OF THE DAY, THIS MAY MITIGATE THE INSTABILITY POTENTIAL. IT APPEARS ANY INSTABILITY IS MARGINAL AND THEREFORE THUNDER WAS NOT ADDED FOR SATURDAY ATTM. AS WE LOSE THE CONTINUOUS ONSHORE FLOW COMPONENT AND THE TROUGH ALOFT WEAKENING THROUGH SATURDAY, THERE SHOULD BE AT LEAST SOME BREAKS OF SUNSHINE. AN AMPLIFYING TROUGH FROM THE GREAT LAKES THEN STARTS TO NEAR OUR AREA TOWARD DAYBREAK SUNDAY. LOW PRESSURE TRACKING TO OUR NORTH WILL PULL A COLD FRONT INTO OUR AREA LATE SATURDAY NIGHT AND THIS FRONT MAY MOVE IN A BIT FASTER. THERE APPEARS TO BE A PLUME OF DEEPER MOISTURE IN COMBINATION WITH FORCING FOR ASCENT TO DRIVE SOME SHOWERS /PERHAPS A BAND OF SHOWERS/ ACROSS MUCH OF OUR AREA. THE STRONGEST FORCING MAY GLANCE OUR NORTHERN AREAS AND THEREFORE THE HIGHEST POPS WERE PLACED THERE LATER AT NIGHT. ANY SHOWERS SHOULD QUICKLY SHIFT OFFSHORE SUNDAY MORNING AS THE COLD FRONT ALSO EXITS, THEN DRIER AIR AND BETTER MIXING WILL PROMOTE SUNSHINE FINALLY RETURNING FOR THE AFTERNOON. IT WILL BE A BIT BREEZY THOUGH SUNDAY IN THE WAKE OF THE COLD FRONT AS LOW-LEVEL LAPSE RATES STEEPEN AND THE PRESSURE GRADIENT TIGHTENS. WE WENT A BIT WARMER THAN MOS FOR SUNDAY ESPECIALLY FOR THE COASTAL PLAIN GIVEN DOWNSLOPING FLOW. HIGH PRESSURE THEN STARTS TO ARRIVE SUNDAY NIGHT ALLOWING THE WINDS TO DIMINISH. FOR MONDAY AND TUESDAY...SOME WEAK RIDGING ARRIVES DURING MONDAY, ALLOWING SURFACE HIGH PRESSURE TO BE OVER OUR CWA TO START BUT IT LOOKS TO SHIFT OFFSHORE LATER MONDAY. THIS WILL ALLOW A SOUTHERLY FLOW TO BECOME BETTER ESTABLISHED AND WITH DOWNSTREAM WAA INCREASING, A WARMER TIME FRAME IS EXPECTED. THE WAA WILL BE USHERED IN VIA A WARM FRONT AS IT CROSSES THE AREA DURING TUESDAY, AND THERE COULD BE ENOUGH LIFT TO PRODUCE SOME SHOWERS OR A THUNDERSTORM MAINLY TUESDAY AFTERNOON AND NIGHT. THE FORECAST CHALLENGE IS THAT THIS FRONT MAY THEN STALL IN OUR AREA AS ENERGY INITIALLY SHEARS EASTWARD ALONG IT. THIS SHEARING ENERGY COULD PRODUCE SOME CONVECTION. FOR WEDNESDAY AND THURSDAY...THE FORECAST CHALLENGE IS WITH THE FRONTAL ZONE AS IT LOOKS TO BE DRAPED ACROSS OUR AREA, HOWEVER A TROUGH AMPLIFYING ACROSS NEW ENGLAND WEDNESDAY MAY PUSH THE FRONT FARTHER SOUTHWARD. THIS SOUTHWARD PUSH COULD BE ENHANCED AS HIGH PRESSURE MAY BUILD DOWN SOME FROM NORTHERN NEW ENGLAND. A TROUGH IN THE MIDWEST HOWEVER PUSHES SURFACE LOW PRESSURE UP THE OHIO VALLEY WEDNESDAY NIGHT INTO THURSDAY, WITH DOWNSTREAM WAA AND SOUTHERLY FLOW ALLOWING THE BOUNDARY TO START LIFTING NORTHWARD SOME AS A WARM FRONT. THIS TIME FRAME SHOULD BE ON THE WARMER SIDE, HOWEVER THIS WILL ULTIMATELY DEPEND ON THE POSITIONING OF THE FRONTAL BOUNDARY AND ANY CONVECTION THAT OCCURS. GIVEN THE UNCERTAINTY, WE BLENDED THE 00Z WPC GUIDANCE IN WITH CONTINUITY AND THEN MADE SOME TWEAKS. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...CIGS GENERALLY VARIABLE 600-1600 FT VSBY 1-4 MI IN SHOWERY RAINS DURING THE MORNING WITH POSSIBLE IMPROVING CONDITIONS DURING THE AFTERNOON. ISOLATED TSTM POSSIBLE DURING THE MORNING KACY/KMIV AND THEN DURING THE AFTN ELSEWHERE. TSTMS NOT IN TAF DUE TO LOW CONFIDENCE AND ISOLATED NATURE. NE WIND...GUSTS 15-23 KT FOR A TIME LATER THIS MORNING-MIDDAY. TONIGHT... MVFR/IFR CONDS IN ST/FOG, POSSIBLE CLUSTERS OF SHOWERS. DIMINISHING NE WIND THIS EVENING NEAR AND N OF I78. OTHERWISE LIGHT WIND TRENDING SOUTH. OUTLOOK... SATURDAY...MVFR/IFR CEILINGS IN THE MORNING SHOULD IMPROVE TO VFR IN THE AFTERNOON. MAINLY SCATTERED SHOWERS ARE ANTICIPATED WHICH CAN LOCALLY REDUCE THE VISIBILITY FOR A TIME, THEN A BAND OF SHOWERS ARRIVES LATE AT NIGHT WITH A COLD FRONT. SOUTHEASTERLY WINDS MAINLY LESS THAN 10 KNOTS, BECOMING SOUTHWEST AT NIGHT. SUNDAY...BRIEF MVFR CONDITIONS IN THE MORNING WITH SOME SHOWERS AS A COLD FRONT MOVES THROUGH, OTHERWISE VFR. WEST TO NORTHWEST WINDS INCREASE TO 12-18 KNOTS WITH GUSTS TO 25 KNOTS, THEN DIMINISH AT NIGHT. MONDAY AND TUESDAY...VFR, THEN POSSIBLY SOME MVFR DURING TUESDAY WITH A CHANCE OF SHOWERS AS A WARM FRONT MOVES THROUGH. WESTERLY WINDS AROUND 10 KNOTS MONDAY, BECOMING LIGHT AT NIGHT THEN SHIFTING TO SOUTHERLY TUESDAY. && .MARINE... LETTING THE SCA ON THE DELAWARE BAY EXPIRE AS WINDS ARE IN THE MID TEENS AND NOT EXPECTED TO INCREASE MUCH THROUGH THE REST OF THE DAY. SCA CONTINUES OCEAN WATERS THROUGH TONIGHT, ESPECIALLY DUE TO SEAS. SMALL CHANCE WE WILL NEED TO UPGRADE TO A SHORT FUSE SHORT DURATION GALE ANZ450-451 FOR THE PERIOD 16Z-21Z. CONFIDENCE IN UPGRADING WAS LESS THAN 80 PCT SO HAVE HELD OFF FOR NOW. FOG MAY BECOME A MARINE HAZARD LATER THIS FRIDAY NIGHT. OUTLOOK... SATURDAY...THE WINDS ARE ANTICIPATED TO BE LIGHT AS A CLOSED LOW INITIALLY OVERHEAD WEAKENS AND THEN SHIFTS EASTWARD. THE SEAS MAY BE RIGHT AT 5 FEET TO START ESPECIALLY ACROSS THE NORTHERN WATERS BUT OVERALL THE CONDITIONS SHOULD BE TRENDING BELOW ADVISORY CRITERIA. THEREFORE WE DID NOT EXTEND THE ADVISORY ATTM. SUNDAY...WEST TO NORTHWEST WINDS TURN GUSTY TO AROUND 20 KNOTS WITH SEAS AT OR BELOW 4 FEET. IT IS POSSIBLE WINDS GUST TO 25 KNOTS NEARSHORE, HOWEVER OVERALL CONDITIONS ARE ANTICIPATED TO BE BELOW ADVISORY CRITERIA. MONDAY AND TUESDAY...SUB-ADVISORY CONDITIONS ARE ANTICIPATED DESPITE SOME INCREASE IN A SOUTHERLY WIND MONDAY AND THEN AGAIN LATER TUESDAY. && .TIDES/COASTAL FLOODING... PLEASE SEE THE HAZARD CFW STATEMENT FOR THE PARTICULARS RELATING TO EACH AREA. PHL: TIDAL DE ADVY EXPIRED BUT MAY NEED A NEW ONE TO BE ISSUED THIS AFTERNOON FOR THE EARLY SATURDAY MORNING HIGH TIDE CYCLE. CONFIDENCE IN EXCEEDING THE ADVY THRESHOLD WAS NOT QUITE CATEGORICAL ON THIS SHIFT. REEDY POINT UPPER DE BAY, LOWER TIDAL DE LINKED: REISSUED FOR LATE THIS EVENING, SINCE CONFIDENCE IS CATEGORICAL THAT IT WILL REOCCUR, ESPECIALLY BECAUSE THE FUNNELED ENE FLOW THIS MORNING TURNS LIGHT SOUTH THIS EVENING. NJ/DE ATLC COASTS: NO CHANGE IN THE PREVIOUS WARNING. THE TIDAL SURGE IS EXPECTED TO STAY AROUND 1 TO 1.5 FEET TODAY IN THE CONTINUING NORTHEASTERLY FLOW. THE THURSDAY EVENING HIGH TIDE SAW MANY OBSERVING SITES EITHER JUST REACH OR FALL JUST SHY OF MODERATE FLOODING THRESHOLDS. WE ARE FORECASTING MINOR TIDAL FLOODING AROUND THIS MORNING`S HIGH TIDE AND MODERATE FLOODING AROUND THIS FRIDAY EVENING`S HIGH TIDE. RATHER THAN CARRY MULTIPLE HEADLINES, WE CONTINUED WITH THE COASTAL FLOOD WARNING TO COVER BOTH HIGH TIDE CYCLES. MINOR TIDAL FLOODING MAY LINGER WITH THE HIGH TIDE CYCLES ON SATURDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...COASTAL FLOOD WARNING UNTIL 1 AM EDT SATURDAY FOR NJZ012>014- 020>027. COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 2 AM EDT SATURDAY FOR NJZ016. DE...COASTAL FLOOD WARNING UNTIL 1 AM EDT SATURDAY FOR DEZ002>004. COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 2 AM EDT SATURDAY FOR DEZ001. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ450>455. && $$ SYNOPSIS...GORSE NEAR TERM...DRAG/MEOLA SHORT TERM...DRAG LONG TERM...GORSE AVIATION...DRAG/GORSE MARINE...DRAG/GORSE/MEOLA TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
634 AM EDT FRI MAY 6 2016 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE INTO OUR AREA FROM THE SOUTHEAST LATER TODAY, THEN LINGER THROUGH SATURDAY BEFORE DISSIPATING. A COLD FRONT WILL MOVE THROUGH SUNDAY MORNING, FOLLOWING BY HIGH PRESSURE SUNDAY NIGHT INTO MONDAY BEFORE MOVING OFFSHORE. A WARM FRONT LIFTS NORTH ACROSS OUR AREA DURING TUESDAY, THEN STALLS IN OUR AREA WEDNESDAY INTO THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CHILLY SHOWERY RAINS THIS MORNING SHOULD TAPER OFF FROM EAST TO WEST DURING THE AFTERNOON THOUGH WITH MOIST INFLOW BENEATH A COOLING 500MB LAYER (-24C NEAR PHL AT 00Z THIS EVENING) WE COULD SEE LOW TOP SHOWERS CONTINUE DEVELOPING NEAR THE COASTS AND SWEEP WESTWARD) . CONSIDERABLE INSTABILITY ALOFT SUGGEST POTENTIAL FOR ISOLATED THUNDER/ASSOCIATED SMALL HAIL WITH VERY STEEP MID LVL LAPSE RATES AND LOW WBZ NEAR 6000 FT. NOT SURE WHAT WILL TRIGGER THE THUNDER EXCEPT SFC CONVERGENCE WITH THE LOW COMING ASHORE AND PERHAPS SOME AFTERNOON SFC HEATING NEAR THE APPROACHING LOW OVER DE. TEMPS MAY BE SEVERAL DEGREES COLDER THAN YDY I95 NWWD. A GUSTY NE WIND FOR A TIME THIS MORNING NEAR 20 MPH EXCEPT GUSTS MIDDAY AND EARLY AFTERNOON MONMOUTH AND OCEAN COUNTIES MAY APPROACH 35 MPH (SEE HRRR GUSTS AS A BAND OF STRONGER WIND WELL NORTH OF THE LOW CENTER SHIFTS WESTWARD WITH LOW ALONG THE S SHORE OF LI). FCST WAS A 50 50 BLEND OF THE 00Z/6 GFS/NAM MOS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... HAVE UNCERTAINTY REGARDING TIMING OF ANY SHOWERS AND ANY LEFTOVER ISOLATED EVENING TSTMS (SE PA/S NJ). CONFIDENCE ON WHAT OCCURS AND WHERE, IS BELOW AVERAGE. IN PART THIS IS DUE TO RECENT LOSS OF CONFIDENCE IN GFS QPF FCSTS. NE WIND DIMINISHING THIS EVENING AND BECOMING LIGHT SOUTHERLY ON THE DELMARVA, POSSIBLY EVEN TO I95. FOG MAY BECOME A PROBLEM TONIGHT WITH A LIGHT WIND IN THE MIDST OF VERTICALLY STACKED MOIST LOW PRESSURE SYSTEM. FCST WAS A 50 50 BLEND OF THE 00Z/6 GFS/NAM MOS. && .LONG TERM /SATURDAY THROUGH THURSDAY/... THE SYNOPTIC SETUP IS COMPRISED OF AN INITIAL CLOSED LOW CENTERED OVER OUR AREA SATURDAY, HOWEVER THIS FEATURE OPENS UP DURING SATURDAY AS IT SHIFTS EASTWARD. THIS OCCURS AS A STRONG SHORT WAVE TROUGH DIVES SOUTHEASTWARD ACROSS THE GREAT LAKES SATURDAY AND INTO THE NORTHEAST SATURDAY NIGHT AND SUNDAY. THE NEW TROUGH AMPLIFIES ACROSS THE NORTHEAST SUNDAY BEFORE GRADUALLY LIFTING OUT MONDAY. A WEAK RIDGE THEN ARRIVES FOR EARLY NEXT WEEK WITH A SURFACE WARM FRONT ALSO MOVING THROUGH. THE WARM FRONT HOWEVER MAY END UP STALLING IN OUR VICINITY WEDNESDAY AND THURSDAY AS ENERGY SHEARS EASTWARD ALONG IT. GIVEN THE PATTERN CHANGE, MUCH WARMER AIR IS EXPECTED TO ARRIVE NEXT WEEK WITH THIS CHANGE STARTING OVER THE WEEKEND ESPECIALLY DURING SUNDAY. THE EXTENT OF THE WARMING THOUGH NEXT WEEK WILL DEPEND ON THE PLACEMENT OF THE FRONTAL BOUNDARY AS IT MAY MEANDER ACROSS OUR CWA AND ALSO PRECIPITATION CHCS. WE USED A MODEL BLEND APPROACH FOR SATURDAY THROUGH SUNDAY NIGHT, THEN BLENDED IN THE 00Z WPC GUIDANCE THEREAFTER. SOME ADJUSTMENTS WERE THEN MADE FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES. FOR SATURDAY AND SUNDAY...THIS TIME FRAME BEGINS WITH A CLOSED LOW RIGHT OVER OUR AREA SATURDAY MORNING, HOWEVER THIS FEATURE WILL OPEN UP AND SHIFT EASTWARD DURING THE COURSE OF THE DAY. THIS WILL BE DUE TO A KICKER SHORT WAVE TROUGH AMPLIFYING ACROSS THE GREAT LAKES REGION. A CORE OF -20C TO -24C AIR AT 500 MB IS OVER OUR AREA SATURDAY MORNING, HOWEVER THIS MODIFIES THROUGH THE DAY AS THE TROUGH OPENS UP AND SHIFTS TO OUR EAST. THE PRESENCE OF COLD AIR ALOFT COMBINED WITH SOME LIFT FROM THE CLOSED LOW SHOULD RESULT IN MAINLY SCATTERED SHOWERS SATURDAY ESPECIALLY INLAND. THE FLOW IS LIGHT UNDER THE CLOSED LOW THEREFORE SHOWERS SHOULD BE SLOW MOVERS. SINCE THE AIRMASS IS WARMING DURING THE COURSE OF THE DAY, THIS MAY MITIGATE THE INSTABILITY POTENTIAL. IT APPEARS ANY INSTABILITY IS MARGINAL AND THEREFORE THUNDER WAS NOT ADDED FOR SATURDAY ATTM. AS WE LOSE THE CONTINUOUS ONSHORE FLOW COMPONENT AND THE TROUGH ALOFT WEAKENING THROUGH SATURDAY, THERE SHOULD BE AT LEAST SOME BREAKS OF SUNSHINE. AN AMPLIFYING TROUGH FROM THE GREAT LAKES THEN STARTS TO NEAR OUR AREA TOWARD DAYBREAK SUNDAY. LOW PRESSURE TRACKING TO OUR NORTH WILL PULL A COLD FRONT INTO OUR AREA LATE SATURDAY NIGHT AND THIS FRONT MAY MOVE IN A BIT FASTER. THERE APPEARS TO BE A PLUME OF DEEPER MOISTURE IN COMBINATION WITH FORCING FOR ASCENT TO DRIVE SOME SHOWERS /PERHAPS A BAND OF SHOWERS/ ACROSS MUCH OF OUR AREA. THE STRONGEST FORCING MAY GLANCE OUR NORTHERN AREAS AND THEREFORE THE HIGHEST POPS WERE PLACED THERE LATER AT NIGHT. ANY SHOWERS SHOULD QUICKLY SHIFT OFFSHORE SUNDAY MORNING AS THE COLD FRONT ALSO EXITS, THEN DRIER AIR AND BETTER MIXING WILL PROMOTE SUNSHINE FINALLY RETURNING FOR THE AFTERNOON. IT WILL BE A BIT BREEZY THOUGH SUNDAY IN THE WAKE OF THE COLD FRONT AS LOW-LEVEL LAPSE RATES STEEPEN AND THE PRESSURE GRADIENT TIGHTENS. WE WENT A BIT WARMER THAN MOS FOR SUNDAY ESPECIALLY FOR THE COASTAL PLAIN GIVEN DOWNSLOPING FLOW. HIGH PRESSURE THEN STARTS TO ARRIVE SUNDAY NIGHT ALLOWING THE WINDS TO DIMINISH. FOR MONDAY AND TUESDAY...SOME WEAK RIDGING ARRIVES DURING MONDAY, ALLOWING SURFACE HIGH PRESSURE TO BE OVER OUR CWA TO START BUT IT LOOKS TO SHIFT OFFSHORE LATER MONDAY. THIS WILL ALLOW A SOUTHERLY FLOW TO BECOME BETTER ESTABLISHED AND WITH DOWNSTREAM WAA INCREASING, A WARMER TIME FRAME IS EXPECTED. THE WAA WILL BE USHERED IN VIA A WARM FRONT AS IT CROSSES THE AREA DURING TUESDAY, AND THERE COULD BE ENOUGH LIFT TO PRODUCE SOME SHOWERS OR A THUNDERSTORM MAINLY TUESDAY AFTERNOON AND NIGHT. THE FORECAST CHALLENGE IS THAT THIS FRONT MAY THEN STALL IN OUR AREA AS ENERGY INITIALLY SHEARS EASTWARD ALONG IT. THIS SHEARING ENERGY COULD PRODUCE SOME CONVECTION. FOR WEDNESDAY AND THURSDAY...THE FORECAST CHALLENGE IS WITH THE FRONTAL ZONE AS IT LOOKS TO BE DRAPED ACROSS OUR AREA, HOWEVER A TROUGH AMPLIFYING ACROSS NEW ENGLAND WEDNESDAY MAY PUSH THE FRONT FARTHER SOUTHWARD. THIS SOUTHWARD PUSH COULD BE ENHANCED AS HIGH PRESSURE MAY BUILD DOWN SOME FROM NORTHERN NEW ENGLAND. A TROUGH IN THE MIDWEST HOWEVER PUSHES SURFACE LOW PRESSURE UP THE OHIO VALLEY WEDNESDAY NIGHT INTO THURSDAY, WITH DOWNSTREAM WAA AND SOUTHERLY FLOW ALLOWING THE BOUNDARY TO START LIFTING NORTHWARD SOME AS A WARM FRONT. THIS TIME FRAME SHOULD BE ON THE WARMER SIDE, HOWEVER THIS WILL ULTIMATELY DEPEND ON THE POSITIONING OF THE FRONTAL BOUNDARY AND ANY CONVECTION THAT OCCURS. GIVEN THE UNCERTAINTY, WE BLENDED THE 00Z WPC GUIDANCE IN WITH CONTINUITY AND THEN MADE SOME TWEAKS. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...CIGS GENERALLY VARIABLE 600-1600 FT VSBY 1-4 MI IN SHOWERY RAINS DURING THE MORNING WITH POSSIBLE IMPROVING CONDITIONS DURING THE AFTERNOON. ISOLATED TSTM POSSIBLE DURING THE MORNING KACY/KMIV AND THEN DURING THE AFTN ELSEWHERE. TSTMS NOT IN TAF DUE TO LOW CONFIDENCE AND ISOLATED NATURE. NE WIND...GUSTS 15-23 KT FOR A TIME LATER THIS MORNING-MIDDAY. TONIGHT... MVFR/IFR CONDS IN ST/FOG, POSSIBLE CLUSTERS OF SHOWERS. DIMINISHING NE WIND THIS EVENING NEAR AND N OF I78. OTHERWISE LIGHT WIND TRENDING SOUTH. OUTLOOK... SATURDAY...MVFR/IFR CEILINGS IN THE MORNING SHOULD IMPROVE TO VFR IN THE AFTERNOON. MAINLY SCATTERED SHOWERS ARE ANTICIPATED WHICH CAN LOCALLY REDUCE THE VISIBILITY FOR A TIME, THEN A BAND OF SHOWERS ARRIVES LATE AT NIGHT WITH A COLD FRONT. SOUTHEASTERLY WINDS MAINLY LESS THAN 10 KNOTS, BECOMING SOUTHWEST AT NIGHT. SUNDAY...BRIEF MVFR CONDITIONS IN THE MORNING WITH SOME SHOWERS AS A COLD FRONT MOVES THROUGH, OTHERWISE VFR. WEST TO NORTHWEST WINDS INCREASE TO 12-18 KNOTS WITH GUSTS TO 25 KNOTS, THEN DIMINISH AT NIGHT. MONDAY AND TUESDAY...VFR, THEN POSSIBLY SOME MVFR DURING TUESDAY WITH A CHANCE OF SHOWERS AS A WARM FRONT MOVES THROUGH. WESTERLY WINDS AROUND 10 KNOTS MONDAY, BECOMING LIGHT AT NIGHT THEN SHIFTING TO SOUTHERLY TUESDAY. && .MARINE... SCA CONTINUES OCEAN WATERS AS PREVIOUSLY OUTLINED THROUGH TONIGHT, ESPECIALLY DUE TO SEAS. DECIDED TO CONTINUE DE BAY SCA SINCE A FEW GUSTS EARLIER NEAR 23 KT. HOWEVER... TRENDS BY MID MORNING SHOULD BE DECREASING DE BAY. SMALL CHANCE WE WILL NEED TO UPGRADE TO A SHORT FUSE SHORT DURATION GALE ANZ450-451 FOR THE PERIOD 16Z-21Z. CONFIDENCE IN UPGRADING WAS LESS THAN 80 PCT SO HAVE HELD OFF FOR NOW. FOG MAY BECOME A MARINE HAZARD LATER THIS FRIDAY NIGHT. OUTLOOK... SATURDAY...THE WINDS ARE ANTICIPATED TO BE LIGHT AS A CLOSED LOW INITIALLY OVERHEAD WEAKENS AND THEN SHIFTS EASTWARD. THE SEAS MAY BE RIGHT AT 5 FEET TO START ESPECIALLY ACROSS THE NORTHERN WATERS BUT OVERALL THE CONDITIONS SHOULD BE TRENDING BELOW ADVISORY CRITERIA. THEREFORE WE DID NOT EXTEND THE ADVISORY ATTM. SUNDAY...WEST TO NORTHWEST WINDS TURN GUSTY TO AROUND 20 KNOTS WITH SEAS AT OR BELOW 4 FEET. IT IS POSSIBLE WINDS GUST TO 25 KNOTS NEARSHORE, HOWEVER OVERALL CONDITIONS ARE ANTICIPATED TO BE BELOW ADVISORY CRITERIA. MONDAY AND TUESDAY...SUB-ADVISORY CONDITIONS ARE ANTICIPATED DESPITE SOME INCREASE IN A SOUTHERLY WIND MONDAY AND THEN AGAIN LATER TUESDAY. && .TIDES/COASTAL FLOODING... PLEASE SEE THE HAZARD CFW STATEMENT FOR THE PARTICULARS RELATING TO EACH AREA. PHL: TIDAL DE ADVY EXPIRED BUT MAY NEED A NEW ONE TO BE ISSUED THIS AFTERNOON FOR THE EARLY SATURDAY MORNING HIGH TIDE CYCLE. CONFIDENCE IN EXCEEDING THE ADVY THRESHOLD WAS NOT QUITE CATEGORICAL ON THIS SHIFT. REEDY POINT UPPER DE BAY, LOWER TIDAL DE LINKED: REISSUED FOR LATE THIS EVENING, SINCE CONFIDENCE IS CATEGORICAL THAT IT WILL REOCCUR, ESPECIALLY BECAUSE THE FUNNELED ENE FLOW THIS MORNING TURNS LIGHT SOUTH THIS EVENING. NJ/DE ATLC COASTS: NO CHANGE IN THE PREVIOUS WARNING. THE TIDAL SURGE IS EXPECTED TO STAY AROUND 1 TO 1.5 FEET TODAY IN THE CONTINUING NORTHEASTERLY FLOW. THE THURSDAY EVENING HIGH TIDE SAW MANY OBSERVING SITES EITHER JUST REACH OR FALL JUST SHY OF MODERATE FLOODING THRESHOLDS. WE ARE FORECASTING MINOR TIDAL FLOODING AROUND THIS MORNING`S HIGH TIDE AND MODERATE FLOODING AROUND THIS FRIDAY EVENING`S HIGH TIDE. RATHER THAN CARRY MULTIPLE HEADLINES, WE CONTINUED WITH THE COASTAL FLOOD WARNING TO COVER BOTH HIGH TIDE CYCLES. MINOR TIDAL FLOODING MAY LINGER WITH THE HIGH TIDE CYCLES ON SATURDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...COASTAL FLOOD WARNING UNTIL 1 AM EDT SATURDAY FOR NJZ012>014- 020>027. COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 2 AM EDT SATURDAY FOR NJZ016. DE...COASTAL FLOOD WARNING UNTIL 1 AM EDT SATURDAY FOR DEZ002>004. COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 2 AM EDT SATURDAY FOR DEZ001. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ450>455. SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR ANZ431. && $$ SYNOPSIS...GORSE NEAR TERM...DRAG 633 SHORT TERM...DRAG 633 LONG TERM...GORSE AVIATION...DRAG/GORSE 633 MARINE...DRAG/GORSE 633 TIDES/COASTAL FLOODING...633
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1015 AM EDT FRI MAY 6 2016 .DISCUSSION... ...UNSEASONABLY COOL THIS MORNING THROUGH TONIGHT... CURRENT-THIS AFTERNOON... NORTHWEST TO NORTH WIND FLOW BETWEEN HIGH PRESSURE CENTERED OVER ARKANSAS BUILDING OVER THE NORTHEAST GULF OF MEXICO AND FLORIDA AND FRONT ASSOCIATED WITH LOW EAST OF THE DELMARVA PENINSULA AND NEW JERSEY TO CONTINUE THROUGH THE AFTERNOON. LOCAL SEA BREEZES POSSIBLE FROM NORTH BREVARD CAPE CANAVERAL NORTH MID TO LATE AFTERNOON PER SHORT TERM SMALL SCALE MODELS SUCH AS THE HRRR AND THE LOCAL WRFARW6. CURRENT AFTERNOON WIND GRIDS REFLECT SEA BREEZE. MORNING ZONE UPDATE WILL CLEAN UP WORDING FOR THE AFTERNOON HOURS. .AVIATION...VFR. WEST NORTHWEST TO NORTH WINDS 10 TO 15 KNOTS WITH OCCASIONAL GUSTS 20 TO 25 KNOTS IN THE AFTERNOON. AIRPORTS AND AIRFIELDS BETWEEN INTERSTATE 95 AND THE COAST FROM COCOA NORTH MAY EXPERIENCE A MID TO LATE AFTERNOON SEA BREEZE. WINDS FALL TO LIGHT AGAIN THIS EVENING. .MARINE... BUOYS RECORDING NORTHWEST WINDS AROUND 15 KNOTS IN THE ATLANTIC AND THE COASTAL CMAN SITES WINDS WERE AROUND 10 KNOTS. THE TWO SCRIPPS BUOYS AT 4 AND 6NM OFF THE BEACH WERE RECORDING 2 TO 3 FEET. THE NOAA BUOYS AT 20NM AND 120NM OFFSHORE WERE RECORDING 5 AND 6 FEET RESPECTIVELY. CURRENT MARINE FORECAST PICKS UP ON A SEA BREEZE WIND IN THE NEARSHORE MARINE ZONE FROM CAPE CANAVERAL NORTH. MORNING UPDATE TO CLEAN UP WORDING AND BRING SEAS DOWN A FOOT OR TWO FOR THE AFTERNOON PERIOD. .FIRE WEATHER... SEVERAL HOURS OF RH`S BETWEEN 25 TO 35 PCT FROM LATE THIS MORNING THRU THE AFTERNOON AREAWIDE. NO RAIN IN THE FORECAST AND WILL SEE ERC VALUES SLOWLY INCREASE BUT THEY SHOULD REMAIN TOO LOW FOR RED FLAG CONDITIONS. 20FT WINDS FROM THE NW AT 10-15 MPH. .CLIMATE... RECORD LOWS FOR FRI MAY 6: DAB 42 1940 MCO 49 1945 MLB 49 1963 VRB 52 1973 RECORD LOWS FOR SAT MAY 7: DAB 45 1940 MCO 49 1921 MLB 53 1992 VRB 52 2013 PREVIOUS AFD ISSUED AT 320 AM EDT FRI MAY 6 2016 CURRENT...ANOTHER REINFORCING COOL FRONT IS PASSING THROUGH ECFL EARLY THIS MORNING AS WITNESSED BY WIND SHIFT FROM WEST TO NORTHWEST AND ON INFRARED SATELLITE IMAGERY BY A THIN CLOUD LINE. THIS WEAK BOUNDARY WILL USHER IN DRIER/COOLER AIR ACROSS THE AREA IN ITS WAKE. SKIES REMAIN MOSTLY CLEAR ASIDE FROM A FEW CLOUDS ASSOCIATED ALONG THE FRONT. LOW TEMPERATURES EARLY THIS MORNING WILL BOTTOM OUT IN THE 50S AREAWIDE...GENERALLY 5-10 DEGREES LOWER THAN SEASONAL NORMS. TODAY-TONIGHT...HIGH PRESSURE CENTERED NEAR THE ARKLATEX REGION WILL SLIDE SOUTH AND EAST ACROSS THE DEEP SOUTH. THE PRESSURE GRADIENT RELAXES A BIT TODAY AS WNW/NW WINDS INCREASE IN THE LATE MORNING AND AFTERNOON TO AROUND 15 MPH WITH OCNL HIGHER GUSTS EXPECTED. THE WIND COMPONENT MAY VEER AROUND TO NNE LATER IN THE AFTERNOON ALONG THE VOLUSIA COAST. SKIES WILL REMAIN MOSTLY SUNNY WITH NO THREAT FOR RAIN. ALOFT...A VIGOROUS UPPER TROUGH ALONG THE EASTERN SEABOARD WILL MOVE ONLY SLIGHTLY EASTWARD SENDING OCNL IMPULSES ACROSS THE AREA. UNSEASONABLY COOL WITH HIGHS MAINLY 70S AREAWIDE. OVERNIGHT LOWS STILL BELOW SEASONAL AND GENERALLY IN THE L-M 50S...EXCEPT U50S POSSIBLE ACROSS LARGER METROPOLITAN AREAS OR ALONG THE IMMEDIATE SPACE/TREASURE COASTS. ANOTHER WEAK BACKDOOR COOL FRONT WILL BRUSH THE LOCAL COASTAL WATERS LATE OVERNIGHT. THE ATMOSPHERE WILL REMAIN TOO DRY/STABLE TO PRODUCE ANY PRECIPITATION OVER LAND. SAT-TUE...AXIS OF THE DEEP WRN ATLC TROUGH SHIFTS EWD SAT AS THE OMEGA BLOCK TO THE NORTH BREAKS DOWN. THIS ALLOWS A MID LEVEL RIDGE TO BUILD EWD ACROSS FL FROM THE GOMEX AND REMAIN ENTRENCHED OVER THE AREA THROUGH EARLY NEXT WEEK. SURFACE HIGH DRIFTS OVER FL INTO THIS WEEKEND KEEPING CONDS WX WARM AND DRY BUT NOT TERRIBLY HUMID. HIGH WILL THEN SLIDE EWD WITH ITS AXIS REMAINING OVER CENTRAL FLORIDA THROUGH EARLY MON THEN LIFT NORTH OF CTRL FL TUE....RESULTING IN A TREND TWD MORE HUMID CONDS. ONE MORE DAY/NIGHT OF SLIGHTLY COOLER THAN NORMAL TEMPS SAT. MAXES NEAR TO A DEGREE OR TWO ABOVE NORMAL EARLY EXT WEEK WITH MINS RUNNING ABOUT 1-2 CATEGORIES ABOVE CLIMO. ECFL NORMALS FOR EARLY MAY ARE ABOUT 85-88F/63-66F. WED-FRI...FOR THE SECOND HALF OF NEXT WEEK...A COUPLE WEAK MID LEVEL PERTURBATIONS BREAK DOWN THE RIDGE ALOFT WITH LIGHT SE/SRLY FLOW AND INCREASING MOISTURE ALLOWING FOR A SLGT CHANCE OF DIURNAL SHRA/TS BY THU (IF NOT WED) PERHAPS A BIT HIGHER BY THE END OF NEXT WEEK. TEMPS REMAIN NEAR OR SLGTLY ABOVE NORMAL THROUGH THE END OF THE WEEK. && .AVIATION...VFR. WNW/NW WINDS 5-10 KTS EARLY THIS MORNING WILL INCREASE LATE MORNING/EARLY AFTERNOON TO 10-15 KTS WITH SOME HIGHER GUSTS. WINDS FALL TO LIGHT AGAIN THIS EVENING. && .MARINE...TODAY-TONIGHT...THE LATEST WEAK FRONTAL BOUNDARY WILL MOVE THROUGH THE AREA VERY EARLY THIS MORNING WITH ELEVATED NW WINDS 15- 20 KTS CONTINUING OVER THE OPEN ATLC...THOUGH THE PRESSURE GRADIENT RELAXES THROUGH THE DAY WITH WIND SPEEDS DECREASING THROUGH THE AFTERNOON. HOWEVER...ANOTHER WEAK FRONTAL TROUGH WILL PASS DOWN THE COASTAL WATERS LATE TONIGHT WITH WNW/NW WINDS INCREASING TOWARDS CAUTIONARY CRITERIA ONCE AGAIN. SEAS STARTING 3-4 FT NEAR SHORE AND 5-6 FT OFFSHORE WILL SUBSIDE TO 2-3 FT NEAR SHORE AND AROUND 4 FT OFFSHORE BY LATE IN THE AFTERNOON. SAT-TUE...NW-NRLY FLOW WILL DECREASE AS SFC RIDGE BUILDS INTO FL THROUGH THIS WEEKEND. SEAS OF 3-4FT WILL SUBSIDE TO 2-3FT AS WINDS DROP AOB 10KT. WINDS WILL TURN LIGHT SRLY MON THEN BACK TO SE AND INCREASE TO 10-15KT TUE AS RIDGE AXIS SHIFTS NORTH OF CTRL FL. SEAS OF 2-3FT MON INCREASING BACK TO 3-4FT INTO TUE. && .FIRE WEATHER...TODAY...SEVERAL HOURS OF RH`S BETWEEN 25 TO 35 PCT FROM LATE THIS MORNING THRU THE AFTERNOON AREAWIDE. NO RAIN IN THE FORECAST AND WILL SEE ERC VALUES SLOWLY INCREASE BUT THEY SHOULD REMAIN TOO LOW FOR RED FLAG CONDITIONS. 20FT WINDS FROM THE NW AT 10-15 MPH. SAT-TUE...SEVERAL HOURS OF CRITICALLY LOW RH VALUES EXPECTED AGAIN SAT AS HIGH PRES RIDGE AND DRY AIR HOLD SWAY. SHALLOW LATE AFTERNOON MODIFICATION EXPECTED MAINLY NEAR THE COAST ON SUN DUE TO LOCAL SEA BREEZE CIRC...HOWEVER CONDITIONS WILL HEIGHTEN FIRE WX SENSITIVITY AREAWIDE THIS WEEKEND. GRADUAL MODIFICATION CONTINUES MON ONWARD AS S-SE FLOW ON BACKSIDE OF RETREATING HIGH TAKE HOLD. && .CLIMATE...NEAR RECORD LOWS THIS MORNING IN VRB AND MLB/VRB FOR SAT MORNING. RECORDS LOOK OUT OF REACH ELSEWHERE. RECORD LOWS FOR FRI MAY 6: DAB 42 1940 MCO 49 1945 MLB 49 1963 VRB 52 1973 RECORD LOWS FOR SAT MAY 7: DAB 45 1940 MCO 49 1921 MLB 53 1992 VRB 52 2013 && .PRELIMINARY POINT TEMPS/POPS... DAB 75 56 78 61 / 0 0 0 0 MCO 77 57 81 61 / 0 0 0 0 MLB 77 58 79 62 / 0 0 0 0 VRB 78 56 79 60 / 0 0 0 0 LEE 77 56 81 61 / 0 0 0 0 SFB 77 56 81 60 / 0 0 0 0 ORL 78 59 81 63 / 0 0 0 0 FPR 78 54 79 59 / 0 0 0 0 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...WIMMER LONG TERM/IMPACT WX/DSS....KELLY
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1141 AM EDT FRI MAY 6 2016 .UPDATE... ISSUED AT 1140 AM EDT FRI MAY 6 2016 A COUPLE OF QUICK UPDATES HAVE BEEN DONE TO FINE TUNE THE HOURLY GRIDS BASED ON OBSERVATIONS AND NEAR TERM MODEL TRENDS. POPS WERE INCREASED SLIGHTLY FOR THIS AFTERNOON EAST OF A SANDY HOOK TO JACKSON TO HARLAN LINE FOR BETTER AGREEMENT WITH SHORT TERM MODEL GUIDANCE...CU DEVELOPMENT AND TRENDS. THE BEST CHANCES FOR ANY SHOWERS WILL BE IN THE BIG SANDY REGION. UPDATE ISSUED AT 635 AM EDT FRI MAY 6 2016 JUST A QUICK UPDATE TO FINE TUNE THE GRIDS PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 405 AM EDT FRI MAY 6 2016 07Z SFC ANALYSIS SHOWS LOW PRESSURE OFF TO THE EAST OF THE APPALACHIANS. WHILE HIGH PRESSURE IS FOUND TO THE SOUTHWEST. A FEW LINGERING LIGHT SHOWERS ARE DRIFTING SOUTH THROUGH FAR EASTERN KENTUCKY FROM THAT EASTERN LOW. IN CONJUNCTION WITH THIS...LOW AND MID LEVEL CLOUDS ARE FOUND CLOSER TO THE VIRGINIA AND WEST VIRGINIA BORDER. IN THE CLEARING TO THE WEST OF THE BORDER AREAS...PATCHY FOG IS NOTED IN THE SOME OF THE OBSERVATIONS. TEMPERATURES ARE RUNNING IN THE LOW TO MID 40S ACROSS THE AREA WITH DEWPOINTS NOT FAR AWAY...WHILE WINDS ARE GENERALLY LIGHT FROM THE NORTHWEST. THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST. THEY ALL DEPICT A CONUS OMEGA BLOCK SHIFTING EAST AND OPENING UP DURING THE NEXT 48 HOURS. A DEEP CLOSED LOW DESCENDING THROUGH THE SOUTHERN APPALACHIANS THIS MORNING WILL PIVOT TO THE NORTHEAST BY EVENING BEFORE BEING PICKED UP BY THE NORTHERN STREAM FLOW AND DEPARTING OFF THE MID ATLANTIC COAST SATURDAY EVENING. IN ITS WAKE...RISING HEIGHTS AND RIDGING WILL SPREAD FROM THE SOUTHERN PLAINS AND ACROSS THE MISSISSIPPI VALLEY TOWARD KENTUCKY. HOWEVER...IN ASSOCIATION WITH A HUDSON BAY UPPER LOW DESCENDING INTO THE GREAT LAKES...A MINOR WAVE WILL SQUEEZE BY EASTERN KENTUCKY TO THE NORTH LATE SATURDAY. GIVEN THE MODEL AGREEMENT HAVE FOLLOWED A GENERAL BLEND WITH A STRONG LEAN TOWARD THE HRRR EARLY ON AND THE NAM12 THEREAFTER. SENSIBLE WEATHER WILL FEATURE A MILDER DAY THAN YESTERDAY AS SOME SUNSHINE RETURNS AND THE COLD AIR DEPARTS TO THE EAST. ISOLATED TO SCATTERED SHOWERS WILL BE FOUND OVER FAR EASTERN KENTUCKY THROUGH THE AFTERNOON. FOR TONIGHT...EXPECT A SMALL RIDGE TO VALLEY SPLIT TO SET UP AHEAD OF A DEVELOPING WARM FRONT WITH PATCHY VALLEY FOG AROUND...SIMILAR TO THIS MORNING. A FEW LIGHT SHOWERS CANNOT BE RULED OUT WITH THAT BOUNDARY THROUGH THE MORNING...ESPECIALLY EAST BY MIDDAY SATURDAY. A COLD FRONT WILL THEN SETTLE SOUTH TOWARD EASTERN KENTUCKY LATER SATURDAY. BETWEEN THESE FEATURES...OUR AREA WILL BE IN THE WARM SECTOR OF A QUICK MOVING SFC LOW AND AS A RESULT COULD SEE SOME CONVECTION DEVELOP WITH FAVORABLE PARAMETERS FOR STRONG TO SEVERE STORMS BUILDING DURING THE AFTERNOON AND INTO THE EVENING. SPECIFICALLY...CAPE WILL BE MODERATE WITH LOW LIS AND VEERING/INCREASING WINDS WITH HEIGHT. WILL HIGHLIGHT THIS FURTHER IN THE FORTHCOMING HWO WITH HAIL AND GUSTY WINDS THE MAIN THREAT. USED THE SHORTBLEND/SUPERBLEND AS A STARTING POINT FOR MOST ELEMENTS WITH SOME MINOR ADJUSTMENTS TO THE AFTERNOON DEWPOINTS AND SOME TERRAIN DIFFERENCES FOR TEMPERATURES TONIGHT. DID ADJUST POPS TO BE A BIT ABOVE THE POPULATION SCHEME...IN THE EAST THROUGH TODAY AND ALSO FOR THE STRONG/SEVERE STORM CONCERNS ON SATURDAY AFTERNOON. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 405 AM EDT FRI MAY 6 2016 THE EXTENDED PORTION OF THE FORECAST BEGINS SATURDAY NIGHT WITH AN ACTIVE PATTERN IN PLACE. UPPER CLOSED LOW OVER THE SOUTHEASTERN CANADA REGION WILL BE IN PLACE THROUGH THE WEEKEND AS IT SLOWLY SHIFTS EAST INTO THE COMING WEEK. THIS FEATURE CONTINUES TO SWING A FEW SHORTWAVES INTO THE LOWER GREAT LAKES REGION THROUGH THE START OF THE NEW WEEK. MEANWHILE...AS A WEAKENING RIDGE OVER THE SOUTHEAST CONTINUES TO WEAKEN AND SHIFT EAST AS WELL WITH ANOTHER UPPER LEVEL LOW OVER THE CENTRAL PLAINS. THIS FEATURE OPENS AND EJECTS EAST INTO THE OHIO VALLEY BY MID WEEK. FOLLOWING THIS...TOWARDS THE END OF THE EXTENDED PERIOD...THE PATTERN BECOMES MORE AMPLIFIED AS ANOTHER UPPER LOW MOVES INTO THE UPPER PLAINS WITH A WEAKENING RIDGE OVER THE OH VALLEY SHIFTING. OVERALL...BOTH THE GFS AND EURO HAVE A DECENT HANDLE ON THE UPPER LEVEL PATTERN THROUGH NEXT WEEK. THOUGH THE GFS IS A BIT MORE DRIER THAN THE EURO...THE BOTTOM LINE IS THAT THE EXTENDED SEEMS QUITE WET AND ACTIVE. THIS SOLUTION IS ALSO CONFIRMED BY THE ALL MODEL BLEND AS WELL KEEPING THE CHANCE OF PRECIP THROUGH JUST ABOUT EVERY DAY OF THE EXTENDED. NEAR THE SURFACE HEADING INTO SATURDAY NIGHT AND SUNDAY...A SURFACE LOW PRESSURE SYSTEM DEVELOPING UP OVER THE CENTRAL PLAINS SETS UP A WARM FRONT INTO THE MIDWEST AND A QUASI STATIONARY BOUNDARY INTO THE OH VALLEY. THIS BOUNDARY BECOMES A FOCUS FOR CONTINUED CONVECTION SATURDAY NIGHT AND SUNDAY. IN FACT...THE EURO MIGHT SUGGEST AN MCS SET UP FOR THIS TIME PERIOD. INSTABILITY AND SHEAR SEEM SUBSTANTIAL FOR ORGANIZED CONVECTION AT LEAST EARLY IN THE SATURDAY NIGHT PERIOD AND AGAIN SUNDAY AFTERNOON FOCUSING ON MAX HEATING. STRONG CAPPING HEADING INTO THE DAY MONDAY WOULD LIMIT CONVECTION A BIT MORE AS THE MENTIONED BOUNDARY LIFTS NORTH. STILL WILL KEEP LOW CHANCE POPS IN THE NORTH CLOSER TO THE BOUNDARY. TUESDAY...THE SYSTEM OUT WEST SHIFTS EAST WITH STRONG UPPER LEVEL SUPPORT. STRONG CONVECTION SEEMS TO DEVELOP AHEAD OF THE COLD FRONT TUESDAY AFTERNOON INTO TUESDAY NIGHT. THIS WILL KEEP LIKELY POPS IN THE FORECAST THROUGH WEDNESDAY AS GFS MODEL SOUNDINGS KEEP GOOD INSTABILITY IN PLACE TUESDAY AND WEDNESDAY AFTERNOON. IN FACT...THIS SYSTEM WILL BE FOLLOWED BY A DISTURBANCE TO MOVE INTO THE AREA ON THURSDAY. MODELS HIGHLIGHT AN ACTIVE EXTENDED FORECAST THROUGH NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 700 AM EDT FRI MAY 6 2016 THE WORST OF THE AVIATION CONDITIONS WILL BE OVER THE NEXT COUPLE OF HOURS AS SCATTERED SHOWERS DRIFT JUST WEST OF SOUTH THROUGH THE FAR EASTERN PARTS OF THE AREA. THESE LOCATIONS...PRIMARILY SJS...WILL SEE THE BEST SHOT AT MVFR CONDITIONS FOR BOTH VIS AND CIGS WITH ANY SHOWER. ELSEWHERE...PATCHY FOG MAY IMPACT A TAF SITE OR TWO WEST OF THE SHOWERS...BUT FOR THE MOST THIS WILL DISSIPATE UPON SUNRISE ALLOWING VFR CONDITIONS TO PREVAIL FOR THE REST OF THE PERIOD. WINDS THROUGH THE PERIOD WILL BE GENERALLY OUT OF THE NORTHWEST AT BETWEEN 5 AND 10 KTS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
700 AM EDT FRI MAY 6 2016 .UPDATE... ISSUED AT 635 AM EDT FRI MAY 6 2016 JUST A QUICK UPDATE TO FINE TUNE THE GRIDS PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 405 AM EDT FRI MAY 6 2016 07Z SFC ANALYSIS SHOWS LOW PRESSURE OFF TO THE EAST OF THE APPALACHIANS. WHILE HIGH PRESSURE IS FOUND TO THE SOUTHWEST. A FEW LINGERING LIGHT SHOWERS ARE DRIFTING SOUTH THROUGH FAR EASTERN KENTUCKY FROM THAT EASTERN LOW. IN CONJUNCTION WITH THIS...LOW AND MID LEVEL CLOUDS ARE FOUND CLOSER TO THE VIRGINIA AND WEST VIRGINIA BORDER. IN THE CLEARING TO THE WEST OF THE BORDER AREAS...PATCHY FOG IS NOTED IN THE SOME OF THE OBSERVATIONS. TEMPERATURES ARE RUNNING IN THE LOW TO MID 40S ACROSS THE AREA WITH DEWPOINTS NOT FAR AWAY...WHILE WINDS ARE GENERALLY LIGHT FROM THE NORTHWEST. THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST. THEY ALL DEPICT A CONUS OMEGA BLOCK SHIFTING EAST AND OPENING UP DURING THE NEXT 48 HOURS. A DEEP CLOSED LOW DESCENDING THROUGH THE SOUTHERN APPALACHIANS THIS MORNING WILL PIVOT TO THE NORTHEAST BY EVENING BEFORE BEING PICKED UP BY THE NORTHERN STREAM FLOW AND DEPARTING OFF THE MID ATLANTIC COAST SATURDAY EVENING. IN ITS WAKE...RISING HEIGHTS AND RIDGING WILL SPREAD FROM THE SOUTHERN PLAINS AND ACROSS THE MISSISSIPPI VALLEY TOWARD KENTUCKY. HOWEVER...IN ASSOCIATION WITH A HUDSON BAY UPPER LOW DESCENDING INTO THE GREAT LAKES...A MINOR WAVE WILL SQUEEZE BY EASTERN KENTUCKY TO THE NORTH LATE SATURDAY. GIVEN THE MODEL AGREEMENT HAVE FOLLOWED A GENERAL BLEND WITH A STRONG LEAN TOWARD THE HRRR EARLY ON AND THE NAM12 THEREAFTER. SENSIBLE WEATHER WILL FEATURE A MILDER DAY THAN YESTERDAY AS SOME SUNSHINE RETURNS AND THE COLD AIR DEPARTS TO THE EAST. ISOLATED TO SCATTERED SHOWERS WILL BE FOUND OVER FAR EASTERN KENTUCKY THROUGH THE AFTERNOON. FOR TONIGHT...EXPECT A SMALL RIDGE TO VALLEY SPLIT TO SET UP AHEAD OF A DEVELOPING WARM FRONT WITH PATCHY VALLEY FOG AROUND...SIMILAR TO THIS MORNING. A FEW LIGHT SHOWERS CANNOT BE RULED OUT WITH THAT BOUNDARY THROUGH THE MORNING...ESPECIALLY EAST BY MIDDAY SATURDAY. A COLD FRONT WILL THEN SETTLE SOUTH TOWARD EASTERN KENTUCKY LATER SATURDAY. BETWEEN THESE FEATURES...OUR AREA WILL BE IN THE WARM SECTOR OF A QUICK MOVING SFC LOW AND AS A RESULT COULD SEE SOME CONVECTION DEVELOP WITH FAVORABLE PARAMETERS FOR STRONG TO SEVERE STORMS BUILDING DURING THE AFTERNOON AND INTO THE EVENING. SPECIFICALLY...CAPE WILL BE MODERATE WITH LOW LIS AND VEERING/INCREASING WINDS WITH HEIGHT. WILL HIGHLIGHT THIS FURTHER IN THE FORTHCOMING HWO WITH HAIL AND GUSTY WINDS THE MAIN THREAT. USED THE SHORTBLEND/SUPERBLEND AS A STARTING POINT FOR MOST ELEMENTS WITH SOME MINOR ADJUSTMENTS TO THE AFTERNOON DEWPOINTS AND SOME TERRAIN DIFFERENCES FOR TEMPERATURES TONIGHT. DID ADJUST POPS TO BE A BIT ABOVE THE POPULATION SCHEME...IN THE EAST THROUGH TODAY AND ALSO FOR THE STRONG/SEVERE STORM CONCERNS ON SATURDAY AFTERNOON. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 405 AM EDT FRI MAY 6 2016 THE EXTENDED PORTION OF THE FORECAST BEGINS SATURDAY NIGHT WITH AN ACTIVE PATTERN IN PLACE. UPPER CLOSED LOW OVER THE SOUTHEASTERN CANADA REGION WILL BE IN PLACE THROUGH THE WEEKEND AS IT SLOWLY SHIFTS EAST INTO THE COMING WEEK. THIS FEATURE CONTINUES TO SWING A FEW SHORTWAVES INTO THE LOWER GREAT LAKES REGION THROUGH THE START OF THE NEW WEEK. MEANWHILE...AS A WEAKENING RIDGE OVER THE SOUTHEAST CONTINUES TO WEAKEN AND SHIFT EAST AS WELL WITH ANOTHER UPPER LEVEL LOW OVER THE CENTRAL PLAINS. THIS FEATURE OPENS AND EJECTS EAST INTO THE OHIO VALLEY BY MID WEEK. FOLLOWING THIS...TOWARDS THE END OF THE EXTENDED PERIOD...THE PATTERN BECOMES MORE AMPLIFIED AS ANOTHER UPPER LOW MOVES INTO THE UPPER PLAINS WITH A WEAKENING RIDGE OVER THE OH VALLEY SHIFTING. OVERALL...BOTH THE GFS AND EURO HAVE A DECENT HANDLE ON THE UPPER LEVEL PATTERN THROUGH NEXT WEEK. THOUGH THE GFS IS A BIT MORE DRIER THAN THE EURO...THE BOTTOM LINE IS THAT THE EXTENDED SEEMS QUITE WET AND ACTIVE. THIS SOLUTION IS ALSO CONFIRMED BY THE ALL MODEL BLEND AS WELL KEEPING THE CHANCE OF PRECIP THROUGH JUST ABOUT EVERY DAY OF THE EXTENDED. NEAR THE SURFACE HEADING INTO SATURDAY NIGHT AND SUNDAY...A SURFACE LOW PRESSURE SYSTEM DEVELOPING UP OVER THE CENTRAL PLAINS SETS UP A WARM FRONT INTO THE MIDWEST AND A QUASI STATIONARY BOUNDARY INTO THE OH VALLEY. THIS BOUNDARY BECOMES A FOCUS FOR CONTINUED CONVECTION SATURDAY NIGHT AND SUNDAY. IN FACT...THE EURO MIGHT SUGGEST AN MCS SET UP FOR THIS TIME PERIOD. INSTABILITY AND SHEAR SEEM SUBSTANTIAL FOR ORGANIZED CONVECTION AT LEAST EARLY IN THE SATURDAY NIGHT PERIOD AND AGAIN SUNDAY AFTERNOON FOCUSING ON MAX HEATING. STRONG CAPPING HEADING INTO THE DAY MONDAY WOULD LIMIT CONVECTION A BIT MORE AS THE MENTIONED BOUNDARY LIFTS NORTH. STILL WILL KEEP LOW CHANCE POPS IN THE NORTH CLOSER TO THE BOUNDARY. TUESDAY...THE SYSTEM OUT WEST SHIFTS EAST WITH STRONG UPPER LEVEL SUPPORT. STRONG CONVECTION SEEMS TO DEVELOP AHEAD OF THE COLD FRONT TUESDAY AFTERNOON INTO TUESDAY NIGHT. THIS WILL KEEP LIKELY POPS IN THE FORECAST THROUGH WEDNESDAY AS GFS MODEL SOUNDINGS KEEP GOOD INSTABILITY IN PLACE TUESDAY AND WEDNESDAY AFTERNOON. IN FACT...THIS SYSTEM WILL BE FOLLOWED BY A DISTURBANCE TO MOVE INTO THE AREA ON THURSDAY. MODELS HIGHLIGHT AN ACTIVE EXTENDED FORECAST THROUGH NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 700 AM EDT FRI MAY 6 2016 THE WORST OF THE AVIATION CONDITIONS WILL BE OVER THE NEXT COUPLE OF HOURS AS SCATTERED SHOWERS DRIFT JUST WEST OF SOUTH THROUGH THE FAR EASTERN PARTS OF THE AREA. THESE LOCATIONS...PRIMARILY SJS...WILL SEE THE BEST SHOT AT MVFR CONDITIONS FOR BOTH VIS AND CIGS WITH ANY SHOWER. ELSEWHERE...PATCHY FOG MAY IMPACT A TAF SITE OR TWO WEST OF THE SHOWERS...BUT FOR THE MOST THIS WILL DISSIPATE UPON SUNRISE ALLOWING VFR CONDITIONS TO PREVAIL FOR THE REST OF THE PERIOD. WINDS THROUGH THE PERIOD WILL BE GENERALLY OUT OF THE NORTHWEST AT BETWEEN 5 AND 10 KTS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
656 AM CDT FRI MAY 6 2016 .UPDATE... ISSUED AT 558 AM CDT FRI MAY 6 2016 ISOLATED THUNDERSTORMS HAVE EXPANDED A LITTLE IN COVERAGE ACROSS SOUTHEAST SOUTH DAKOTA...AND MAY CLIP KNOX/CEDAR COUNTIES EARLY THIS MORNING. NO MODEL HAD A REAL HANDLE ON THIS...WITH MOST RECENT RUNS OF THE OPERATIONAL HRRR FINALLY CATCHING ON BY 09Z. NOTHING MORE THAN A PASSING SPRINKLE...MAYBE WITH A RUMBLE OF THUNDER. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 252 AM CDT FRI MAY 6 2016 QUIET AND VERY WARM WEATHER TODAY...THEN MORE ACTIVE AND WET WEATHER SATURDAY AND SUNDAY. UPPER RIDGE REMAINS FIRM ACROSS THE WESTERN HIGH PLAINS WITH CLOSED LOWS ACROSS BOTH COASTS. THIS RESULTS IN ONE MORE DRY DAY WITH BREEZY SOUTHERLY WINDS DEVELOPING TODAY WITH MOSTLY SUNNY SKIES. GUIDANCE REMAINS VERY WARM TODAY WITH HIGHS PROBABLY REACHING THE LOWER TO MID 80S. THIS WILL RESULT IN AFTERNOON HUMIDITY DROPPING INTO THE UPPER 20S TO LOWER 30S...BUT STILL TOO HIGH FOR ANY RED FLAG FIRE CONCERNS. THESE HIGHS ARE ALSO WELL BELOW ANY MAX TEMP RECORDS TODAY WHICH RANGE FROM 95 TO 101. THERE IS A COLD FRONT MOVING OUT OF THE NORTHERN ROCKIES...AND WILL CONTINUE TO BE PUSHED BY AN UPPER TROUGH MOVING THROUGH CENTRAL CANADA. THIS FRONT SETTLES SOUTHWARD INTO THE FORECAST AREA TOWARD I80 THROUGH DAYBREAK SATURDAY. THIS COULD RESULT IN A SLIGHT CHANCE OF THUNDERSTORMS GENERALLY ALONG/NORTH OF IT AFTER MIDNIGHT. PRECIP COULD VERY WELL EVEN REMAIN JUST NORTH OF THE AREA TONIGHT ACROSS SOUTHERN SOUTH DAKOTA. SATURDAY...THE FRONT SETTLES A LITTLE FURTHER SOUTH BUT NOT MUCH. THIS SETS UP A PRETTY TIGHT TEMPERATURE GRADIENT FROM SOUTH TO NORTH. HIGHS NORTH OF THE FRONT IN THE MID 60S...BUT NEAR 80 ALONG THE KS/NE BORDER. THERE COULD BE ISOLATED REMNANTS FROM ANY CONVECTION NORTH OF THE BOUNDARY SATURDAY MORNING. BUT...AGAIN IT COULD ALSO BE DRY AS UPPER RIDGING REMAINS IN PLACE...WITH NO SIGNIFICANT FORCING OTHERWISE. WITH THE FRONT BECOMING STATIONARY ACROSS SOUTHERN NEBRASKA SATURDAY AFTERNOON...INSTABILITY DOES BUILD NEAR IT. A WEAK CAP MAY HOLD WITH CONVECTION DEVELOPING FURTHER WEST ACROSS THE WESTERN HIGH PLAINS. WILL MAINTAIN A SLIGHT CHANCE OF THUNDERSTORMS SATURDAY AFTERNOON...BUT MOST AREAS WILL PROBABLY REMAIN DRY. IF A STORM WOULD DEVELOP...THERE IS JUST A MARGINAL RISK THAT IT COULD BE SEVERE. SATURDAY NIGHT NIGHT...ELEVATED CONVECTION MAY DEVELOP NORTH OF THE SURFACE FRONT AS DEPICTED BY VARIOUS MODELS. HOWEVER...THE NAM IS ALSO HINTING THAT A WEAK PIECE OF ENERGY EJECTING FROM THE MAIN LOW ACROSS THE CENTRAL ROCKIES MAY BE ENOUGH TO TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS. THUS WILL MAINTAIN CHANCE POPS SATURDAY NIGHT. SUNDAY IS TRICKY AS MODEL ARE NOT IN GOOD AGREEMENT ON PLACEMENT OF CONVECTION THROUGH THE DAY. THERE COULD BE LINGERING ACTIVITY EARLY SUNDAY MORNING. STRONGER STORMS COULD DEVELOP SUNDAY AFTERNOON AS LOW LEVEL MOISTURE CONTINUES TO BUILD WITH DEWPOINTS RISING INTO THE MID TO UPPER 50S AND POSSIBLY EVEN LOWER 60S. ANY MORNING CONVECTION COULD HAVE IMPLICATIONS ON AFTERNOON DEVELOPMENT... THUS CONFIDENCE IS LOW OF THE DETAILS AT THIS POINT. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 252 AM CDT FRI MAY 6 2016 PRECIP CHANCE SUBSTANTIALLY INCREASE SUNDAY NIGHT AS UPPER LOW BEGINS TO MOVE ONTO THE PLAINS AND FRONTAL BOUNDARY SHIFTS NORTHWARD ACROSS THE FORECAST AREA. WILL HAVE TO WATCH FOR SEVERE STORMS SUNDAY EVENING...AND MAYBE EVEN OVERNIGHT AS ELEVATED STORMS WILL STILL BE POSSIBLE. ONE HALF TO ONE AND ONE HALF INCHES OF RAIN WILL ALSO BE POSSIBLE SUNDAY NIGHT ACROSS THE REGION. PW VALUES INCREASE TO ABOUT 1.5 STANDARD DEVIATIONS ABOVE NORMAL BASED ON NAEFS CLIMATOLOGY DURING THIS TIME. THUNDERSTORM CHANCES REMAIN IN THE LIKELY CATEGORY THROUGH MONDAY AS SURFACE LOW/FRONTAL BOUNDARY REMAIN IN THE REGION. COULD ALSO BE A SEVERE RISK ON MONDAY AS WELL...WITH PRECIP THREAT CONTINUING INTO MONDAY NIGHT AS THE FRONT SHIFTS EASTWARD. TUESDAY WILL MAINTAIN A SMALL CHANCE OF SHOWERS/ISOLATED STORMS BASED ON OLDER MODEL BLENDS...BUT REALLY THE NEWER MODELS ARE SHOWING IT COULD BE DRY AS WE ARE BETWEEN SYSTEMS. ANOTHER WEAK WAVE COULD MOVE INTO THE AREA ON WEDNESDAY WHICH MAY BRING ONE MORE SMALL CHANCE OF SHOWERS/ISOLATED STORMS...WITH DRY WEATHER THURSDAY. && .AVIATION...(12Z TAFS FOR KOMA...KLNK...KOFK THROUGH 12Z SATURDAY) ISSUED AT 627 AM CDT FRI MAY 6 2016 VFR CONDITIONS THROUGH THE TAF PERIOD. A FEW SHOWERS WITH ISOLATED THUNDER DEVELOPED WITH A LOW LEVEL JET IN SOUTH DAKOTA. THESE COULD LAST ANOTHER A COUPLE HOURS...BUT TOO SMALL A CHANCE TO INCLUDE AT KOFK. SOUTH WINDS WILL INCREASE TO 12 TO 18KT WITH GUSTS TO 25KTS...THEN DECREASES TO 5 TO 10 KTS THIS EVENING. A LOW LEVEL JET WILL INCREASE TO 45KTS LATER TONIGHT NEAR KLNK. THIS COULD SPARK A FEW STORMS. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ UPDATE...DEWALD SHORT TERM...DEWALD LONG TERM...DEWALD AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
600 AM CDT FRI MAY 6 2016 .UPDATE... ISSUED AT 558 AM CDT FRI MAY 6 2016 ISOLATED THUNDERSTORMS HAVE EXPANDED A LITTLE IN COVERAGE ACROSS SOUTHEAST SOUTH DAKOTA...AND MAY CLIP KNOX/CEDAR COUNTIES EARLY THIS MORNING. NO MODEL HAD A REAL HANDLE ON THIS...WITH MOST RECENT RUNS OF THE OPERATIONAL HRRR FINALLY CATCHING ON BY 09Z. NOTHING MORE THAN A PASSING SPRINKLE...MAYBE WITH A RUMBLE OF THUNDER. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 252 AM CDT FRI MAY 6 2016 QUIET AND VERY WARM WEATHER TODAY...THEN MORE ACTIVE AND WET WEATHER SATURDAY AND SUNDAY. UPPER RIDGE REMAINS FIRM ACROSS THE WESTERN HIGH PLAINS WITH CLOSED LOWS ACROSS BOTH COASTS. THIS RESULTS IN ONE MORE DRY DAY WITH BREEZY SOUTHERLY WINDS DEVELOPING TODAY WITH MOSTLY SUNNY SKIES. GUIDANCE REMAINS VERY WARM TODAY WITH HIGHS PROBABLY REACHING THE LOWER TO MID 80S. THIS WILL RESULT IN AFTERNOON HUMIDITY DROPPING INTO THE UPPER 20S TO LOWER 30S...BUT STILL TOO HIGH FOR ANY RED FLAG FIRE CONCERNS. THESE HIGHS ARE ALSO WELL BELOW ANY MAX TEMP RECORDS TODAY WHICH RANGE FROM 95 TO 101. THERE IS A COLD FRONT MOVING OUT OF THE NORTHERN ROCKIES...AND WILL CONTINUE TO BE PUSHED BY AN UPPER TROUGH MOVING THROUGH CENTRAL CANADA. THIS FRONT SETTLES SOUTHWARD INTO THE FORECAST AREA TOWARD I80 THROUGH DAYBREAK SATURDAY. THIS COULD RESULT IN A SLIGHT CHANCE OF THUNDERSTORMS GENERALLY ALONG/NORTH OF IT AFTER MIDNIGHT. PRECIP COULD VERY WELL EVEN REMAIN JUST NORTH OF THE AREA TONIGHT ACROSS SOUTHERN SOUTH DAKOTA. SATURDAY...THE FRONT SETTLES A LITTLE FURTHER SOUTH BUT NOT MUCH. THIS SETS UP A PRETTY TIGHT TEMPERATURE GRADIENT FROM SOUTH TO NORTH. HIGHS NORTH OF THE FRONT IN THE MID 60S...BUT NEAR 80 ALONG THE KS/NE BORDER. THERE COULD BE ISOLATED REMNANTS FROM ANY CONVECTION NORTH OF THE BOUNDARY SATURDAY MORNING. BUT...AGAIN IT COULD ALSO BE DRY AS UPPER RIDGING REMAINS IN PLACE...WITH NO SIGNIFICANT FORCING OTHERWISE. WITH THE FRONT BECOMING STATIONARY ACROSS SOUTHERN NEBRASKA SATURDAY AFTERNOON...INSTABILITY DOES BUILD NEAR IT. A WEAK CAP MAY HOLD WITH CONVECTION DEVELOPING FURTHER WEST ACROSS THE WESTERN HIGH PLAINS. WILL MAINTAIN A SLIGHT CHANCE OF THUNDERSTORMS SATURDAY AFTERNOON...BUT MOST AREAS WILL PROBABLY REMAIN DRY. IF A STORM WOULD DEVELOP...THERE IS JUST A MARGINAL RISK THAT IT COULD BE SEVERE. SATURDAY NIGHT NIGHT...ELEVATED CONVECTION MAY DEVELOP NORTH OF THE SURFACE FRONT AS DEPICTED BY VARIOUS MODELS. HOWEVER...THE NAM IS ALSO HINTING THAT A WEAK PIECE OF ENERGY EJECTING FROM THE MAIN LOW ACROSS THE CENTRAL ROCKIES MAY BE ENOUGH TO TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS. THUS WILL MAINTAIN CHANCE POPS SATURDAY NIGHT. SUNDAY IS TRICKY AS MODEL ARE NOT IN GOOD AGREEMENT ON PLACEMENT OF CONVECTION THROUGH THE DAY. THERE COULD BE LINGERING ACTIVITY EARLY SUNDAY MORNING. STRONGER STORMS COULD DEVELOP SUNDAY AFTERNOON AS LOW LEVEL MOISTURE CONTINUES TO BUILD WITH DEWPOINTS RISING INTO THE MID TO UPPER 50S AND POSSIBLY EVEN LOWER 60S. ANY MORNING CONVECTION COULD HAVE IMPLICATIONS ON AFTERNOON DEVELOPMENT... THUS CONFIDENCE IS LOW OF THE DETAILS AT THIS POINT. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 252 AM CDT FRI MAY 6 2016 PRECIP CHANCE SUBSTANTIALLY INCREASE SUNDAY NIGHT AS UPPER LOW BEGINS TO MOVE ONTO THE PLAINS AND FRONTAL BOUNDARY SHIFTS NORTHWARD ACROSS THE FORECAST AREA. WILL HAVE TO WATCH FOR SEVERE STORMS SUNDAY EVENING...AND MAYBE EVEN OVERNIGHT AS ELEVATED STORMS WILL STILL BE POSSIBLE. ONE HALF TO ONE AND ONE HALF INCHES OF RAIN WILL ALSO BE POSSIBLE SUNDAY NIGHT ACROSS THE REGION. PW VALUES INCREASE TO ABOUT 1.5 STANDARD DEVIATIONS ABOVE NORMAL BASED ON NAEFS CLIMATOLOGY DURING THIS TIME. THUNDERSTORM CHANCES REMAIN IN THE LIKELY CATEGORY THROUGH MONDAY AS SURFACE LOW/FRONTAL BOUNDARY REMAIN IN THE REGION. COULD ALSO BE A SEVERE RISK ON MONDAY AS WELL...WITH PRECIP THREAT CONTINUING INTO MONDAY NIGHT AS THE FRONT SHIFTS EASTWARD. TUESDAY WILL MAINTAIN A SMALL CHANCE OF SHOWERS/ISOLATED STORMS BASED ON OLDER MODEL BLENDS...BUT REALLY THE NEWER MODELS ARE SHOWING IT COULD BE DRY AS WE ARE BETWEEN SYSTEMS. ANOTHER WEAK WAVE COULD MOVE INTO THE AREA ON WEDNESDAY WHICH MAY BRING ONE MORE SMALL CHANCE OF SHOWERS/ISOLATED STORMS...WITH DRY WEATHER THURSDAY. && .AVIATION...(06Z TAFS FOR KOMA...KLNK...KOFK THROUGH 06Z SATURDAY) ISSUED AT 1043 PM CDT THU MAY 5 2016 VFR CONDITIONS WILL CONTINUE THROUGH THE TAF CYCLE. SOUTHERLY RETURN FLOW AROUND DEPARTING SURFACE HIGH PRESSURE WILL ALLOW WINDS TO INCREASE THROUGH THE DAY FRIDAY. A FEW CLOUDS MID CLOUDS MAY DEVELOP LATE IN THE PERIOD BUT REMAIN VFR. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ UPDATE...DEWALD SHORT TERM...DEWALD LONG TERM...DEWALD AVIATION...KERN
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
850 AM PDT FRI MAY 6 2016 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE INTO SOUTHERN NEVADA PROVIDING SCATTERED SHOWERS AND THUNDERSTORMS ALONG WITH MUCH COOLER TEMPERATURES THROUGH SUNDAY. DRIER CONDITIONS ALONG WITH A WARMING TREND WILL OCCUR NEXT WEEK WITH TEMPERATURES WELL ABOVE NORMAL BY THE MIDDLE OF NEXT WEEK. && .UPDATE...A RELATIVELY SMALL BAND OF THUNDERSTORMS IGNITED OVER SOUTHERN AND CENTRAL CLARK COUNTY THIS MORNING WHILE MOSTLY CLEAR SKIES WERE EVIDENT ON EITHER SIDE OF IT. SMALL HAIL AND RAINFALL AMOUNTS UP TO A QUARTER-INCH HAVE BEEN OBSERVED IN THE LAS VEGAS VALLEY SO FAR THIS MORNING. THE LATEST HRRR DEPICTS THAT THIS BAND WILL EXPAND FROM NORTHWEST ARIZONA ACROSS MUCH OF SOUTHERN AND SOUTH CENTRAL NEVADA THE REST OF THE MORNING THROUGH THE AFTERNOON...CLOSE TO WHAT WAS ALREADY INDICATED IN THE INHERITED GRIDS. THE CENTER OF THE INCOMING CLOSED LOW WAS NEAR ANAHEIM THIS MORNING AND CONVECTION NEAR THIS CENTER SHOULD SPREAD ACROSS SOUTHWEST SAN BERNARDINO COUNTY THIS AFTERNOON. THE POP/WX GRIDS WERE UPDATED TO REFLECT THESE LATEST TRENDS. THE REST OF THE FORECAST DETAILED IN THE PREVIOUS DISCUSSION LOOK ON TRACK. && .AVIATION...FOR MCCARRAN...THIS MORNINGS BAND OF RAINSHOWERS AND THUNDERSTORMS HAVE PUSHED NORTH OVER THE LAS VEGAS AREA. CLEARING SKIES FOR THE REST OF THE MORNING WILL LEAD TO ANOTHER ROUND OF SHOWER AND THUNDERSTORMS BEGINNING EARLY THIS AFTERNOON (AFT 20Z). THESE SHOULD AFFECT THE MCCARRAN TERMINAL UNTIL ABOUT 00Z. WINDS SHOULD REMAIN IN A SOUTHERLY TO SOUTHWESTERLY DIRECTION FOR MOST OF THE DAY EXCEPT IN THE VICINITY OF THUNDERSTORMS WHERE WINDS COULD BE GUSTY AND ERRATIC. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...CLOUDS AND SHOWER ACTIVITY WILL INCREASE THROUGHOUT THE DAY WITH THUNDERSTORMS ALSO POSSIBLE...ESPECIALLY THIS AFTERNOON AND EARLY EVENING. GUSTY AND ERRATIC WINDS ARE POSSIBLE AROUND SHOWERS AND THUNDERSTORMS. OTHERWISE...EXPECTING MAINLY A SOUTHERLY WIND ACROSS THE AREA 10-15 KTS AND SOME GUSTS AROUND 20 KTS. CIGS WITH SHOWERS MAINLY 5-7K FT BUT COULD DROP AS LOW AS 3K FT. && .PREV DISCUSSION... 250 AM PDT FRI MAY 6 2016 .SHORT TERM...THROUGH SUNDAY NIGHT. UPPER LOW IS EXPECTED TO MOVE INTO SOUTHERN CALIFORNIA/SOUTHERN NEVADA DURING THE DAY PROVING ENOUGH MOISTURE AND ENERGY FOR SCATTERED SHOWERS AND THUNDERSTORMS. THERE HAS BEEN FAIRLY PERSISTENT ACTIVITY THIS MORNING ACROSS NORTHERN INYO AND ESMERALDA COUNTIES WHERE THE BEST FORCING HAS BEEN LOCATED. RAINFALL AMOUNTS HAVE GENERALLY BEEN MARGINAL AS THESE CELLS HAVE BEEN MOVING FAIRLY QUICKLY. ADDITIONAL ISOLATED SHOWERS HAVE BEEN DEVELOPING ACROSS THE EASTERN HALF OF THE CWA OVERNIGHT...BUT FORCING OVER THIS AREA HAS BEEN MUCH WEAKER AND THESE CELLS ARE NOT LASTING TOO LONG. LOOKS LIKE MOST OF THE SOUTHERN TWO THIRDS OF THE CWA WILL START OUT WITH MOSTLY SUNNY SKIES...BUT CLOUDS WILL QUICKLY DEVELOP AS THE ATMOSPHERE BECOME MORE UNSTABLE AS THE DAY WEARS ON. LI VALUES ARE EXPECTED TO DROP TO AROUND 0/-3 BY EARLY AFTERNOON AND CAPE VALUES WILL ALSO INCREASE. THIS WILL LEAD TO SCATTERED SHOWERS AND THUNDERSTORMS OVER MUCH OF THE REGION. PW VALUES ARE FORECAST TO BE AROUND 0.50-0.65 INCHES SO SOME OF THE HEAVIER STORMS COULD PRODUCE PERIODS OF HEAVY RAIN. WITH THE UPPER LOW DIRECTLY OVERHEAD SNOW LEVELS ARE EXPECTED TO BE DOWN TO AROUND 6500-7000 FEET AND ITS LIKELY SOME OF THE HIGHER PEAKS WILL SEE A FEW INCHES OF NEW SNOW. THE BEST SHEAR VALUES WILL REMAIN ACROSS LINCOLN...CENTRAL NYE... ESMERALDA...AND NORTHERN INYO COUNTIES THROUGH THE DAY. THIS AREA COULD SEE MORE PERSISTENT STORMS WITH SOME STRONG STORMS POSSIBLE. WITH THE COLD UPPER LEVELS SMALL HAIL WILL ALSO BE POSSIBLE WITH ANY STORM. WITH LOSS OF DAYTIME HEATING WE WILL LOSE SOME OF THE ENERGY FOR STORMS TO CONTINUE...HOWEVER WITH THE DYNAMICS OF THE UPPER LOW OVERHEAD ITS LIKELY THAT A FEW SHOWERS AND THUNDERSTORMS WILL PERSIST OVERNIGHT. THE UPPER LOW WILL STILL BE OVERHEAD ON SATURDAY LEADING TO ANOTHER DAY OF SCATTERED MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS. CONDITIONS ARE NOT EXPECTED TO BE AS UNSTABLE AS WE SAW ON FRIDAY...BUT STILL ENOUGH TO GENERATE SCATTERED STORMS. ONCE AGAIN SMALL HAIL AND HEAVY RAIN WILL BE POSSIBLE WITH ANY STORM. TEMPERATURES WILL COOL SIGNIFICANTLY WITH HIGHS TODAY ABOUT 15 DEGREES COLDER THAN WE SAW ON THURSDAY. ONLY SLIGHTLY WARMER CONDITIONS ON SATURDAY...BUT BY SUNDAY AFTERNOON READINGS SHOULD JUMP ABOUT 7-9 DEGREES. .LONG TERM...MONDAY THROUGH THURSDAY. THE UPPER LOW WILL BE OFF TO THE EAST BY MONDAY WITH A WEAK NORTHWEST FLOW OVER THE AREA AND RIDGING OFF THE CALIFORNIA COAST. THE MODELS ARE GENERALLY IN AGREEMENT KEEPING A BIT OF MOISTURE LINGERING ALONG WITH SOME WEAK INSTABILITY KEEPING A SLIGHT CHANCE OF SHOWERS OVER MAINLY LINCOLN AND MOHAVE COUNTY. TEMPERATURES WILL BEGIN TO WARM SIGNIFICANTLY. THE MODELS KEEP A WEAK CYCLONIC NORTHWEST FLOW AROUND TUESDAY AND WEDNESDAY AS WELL AND NOT REALLY FLUSHING OUT THE LINGERING MOISTURE. STILL CANNOT RULE OUT A SLIGHT CHANCE OF AFTERNOON SHOWERS OVER THE SIERRA AND POSSIBLY THE HIGHER TERRAIN OF LINCOLN COUNTY AS WELL. MOST MODELS TREND TOWARD WEAK RIDGING BY THURSDAY BUT STILL KEEP ENOUGH MOISTURE AROUND FOR A SLIGHT CHANCE OF SHOWERS OVER THE SIERRA IN THE AFTERNOON. TEMPERATURES CONTINUE TO WARM THROUGH THE LONG TERM WITH HIGH TEMPERATURES AROUND 5 DEGREES ABOVE NORMAL BY THURSDAY. && .SPOTTER INFORMATION STATEMENT...ACTIVE WEATHER IS EXPECTED THROUGH THE WEEKEND. SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER ACCORDING TO STANDARD OPERATING PROCEDURES. && $$ UPDATE...ADAIR SHORT TERM...GORELOW LONG TERM/AVIATION...HARRISON FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE: HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER !--NOT SENT--!
AREA FORECAST DISCUSSION
NWS MEDFORD OR
502 AM PDT FRI MAY 6 2016 .AVIATION...FOR THE 06/12Z TAF CYCLE...A MIX OF MVFR AND VFR CONDITIONS WILL CONTINUE THROUGH LATE MORNING AT ALL TERMINALS. SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EAST SIDE EARLY THIS AFTERNOON AND THEN MOVE FROM EAST TO WEST ACROSS THE AREA. THE GREATEST THREAT FOR THUNDERSTORMS IS FROM THE CASCADES/SISKIYOUS EAST, BUT STORMS MAY ADVANCE AS FAR WEST AS JACKSON/JOSEPHINE COUNTY (INCLUDING KMFR) LATE THIS AFTERNOON. ANY STORMS WILL BE CAPABLE OF PRODUCING IFR CIGS/VIS, VERY HEAVY RAIN, SMALL HAIL, AND GUSTY WINDS. SHOWERS AND STORMS DIMINISH LATE THIS EVENING. -WRIGHT && .MARINE...UPDATED 500 AM PDT FRI 6 MAY 2016...FEW CHANGES WERE MADE TO THE MARINE FORECAST THIS MORNING. NORTH WINDS WILL INCREASE AGAIN THIS AFTERNOON AND CONTINUE INTO THE EVENING. THIS TREND OF STRONG NORTH WINDS/STEEP SEAS IN THE AFTERNOON/EVENINGS AND LULLS AT NIGHT WILL LIKELY CONTINUE THROUGH THE WEEKEND. A GALE WARNING REMAINS IN EFFECT THROUGH THIS EVENING OVER THE SOUTHERN WATERS WITH SMALL CRAFT ADVISORIES ELSEWHERE. MODELS HAVE MAINTAINED THE POTENTIAL FOR GALES OVER THE WEEKEND AND GALE WATCHES REMAIN IN EFFECT. THESE WILL LIKELY BE UPGRADED LATER TODAY. -WRIGHT && .PREV DISCUSSION... /ISSUED 339 AM PDT FRI MAY 6 2016/ DISCUSSION...A MOIST AND UNSTABLE AIR MASS CONTINUES OVER MUCH OF THE FORECAST AREA TODAY...AND WILL HELP GENERATE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS...PRIMARILY FOCUSED OVER NORTHERN CALIFORNIA AND FROM THE CASCADES EASTWARD. THE CUTOFF LOW THAT DOESN`T QUIT REMAINS OVER SOUTHERN CALIFORNIA...SLOWLY MOVING TO THE EAST AND FEEDING THE AREA WITH DEEP MOISTURE AND DISTURBANCES FROM THE SOUTHEAST. THE INTERSECTION OF DEEP MOISTURE...INSTABILITY...AND FAVORABLE DYNAMICS WILL BE MOST PROMINENT IN EASTERN SISKIYOU...MODOC...AND LAKE COUNTIES TODAY. THE WRF ARW AND NMM SHOW STORMS AND HEAVY RAINFALL FROM MOUNT SHASTA EASTWARD TO ALTURAS AND NORTHEAST TO LAKEVIEW THIS AFTERNOON AND EVENING AS SHORTWAVE ENERGY MOVES IN FROM THE EAST PER THE NAM AND SREF MODEL OUTPUT. THE LATEST HRRR OUTPUT IS SUGGESTING SIMILAR. GIVEN CURRENT SNOW DEPTH OVER THE WARNER MOUNTAINS OF 62 INCHES PER DISMAL SWAMP SNOTEL...AND FORECAST SNOW LEVELS OF 9500 FEET...THIS DEFINITELY PROVIDES THE POTENTIAL FOR RAPID SNOW MELT AND FLASH FLOODING. A FLASH FLOOD WATCH CONTINUES FOR THE SOUTHERN HALF OF SISKIYOU COUNTY...MODOC...EXTREME EASTERN KLAMATH...AND MOST OF LAKE COUNTY. PRECIPITABLE WATER VALUES IN THE TOP 10 PERCENT FOR THIS TIME OF YEAR ALSO SUPPORT THE FFA AREA. THE WESTERN FRINGES OF THIS HAZARD AREA ARE LESS LIKELY TO SEE ANY HEAVY RAIN PROBLEMS BUT HAVE LEFT THE AREA INTACT FROM THE PREVIOUS ISSUANCE GIVEN THE UNCERTAINTY OF EXACT HEAVY RAIN LOCATIONS...AND WITH LATEST HRRR OUTPUT LINING UP PRETTY NICELY WITH THE HAZARD AREA. ADDITIONALLY...THE STORM PREDICTION CENTER HAS MAINTAINED A MARGINAL RISK FOR SEVERE STORMS OVER MODOC AND SOUTHERN LAKE COUNTIES. EASTERN SISKIYOU COUNTY ALSO FEATURES A CHANCE FOR SEVERE THUNDERSTORMS WITH FORECAST MOST UNSTABLE CAPES OF 2000+ J/KG, LI VALUES -4 TO -6, AND 0-6KM BULK SHEAR VALUES OF 30+KT. STRONG WINDS, HAIL, AND HEAVY RAIN ARE ALL A POSSIBILITY TODAY. LATEST SATELLITE IMAGERY SHOWS THAT THE DAY SHOULD START OUT SUNNY IN MANY PLACES EAST OF THE CASCADES...WHICH WILL YIELD UNINHIBITED SURFACE HEATING AND POTENTIALLY MAX OUT THE INSTABILITY THIS AFTERNOON. INSTABILITY DIMINISHES TONIGHT AND SHOWERS AND THUNDERSTORMS FOLLOW SUIT. ON SATURDAY A DRYING AIR MASS WEST OF THE CASCADES WILL YIELD SUNNY AND WARM CONDITIONS WHILE THUNDERSTORMS REMAIN POSSIBLE IN MODOC COUNTY. TEMPERATURES WILL BE ABOUT 10 DEGREES ABOVE NORMAL WEST OF THE CASCADES. BY SUNDAY COOL AND DRY NORTHWEST FLOW ALOFT ELIMINATES THE CHANCE FOR SHOWERS OVER THE VAST MAJORITY OF THE FORECAST AREA...WHILE A DEEPENING MARINE LAYER COULD BRING DRIZZLE TO THE COAST. ON MONDAY A WARM TREND BEGINS THAT WILL LAST INTO THE MIDDLE OF THE WEEK AT LEAST...WITH TEMPERATURES MONDAY EXPECTED TO BE A FEW DEGREES ABOVE NORMAL. A PORTION OF THE PREVIOUS LONG-TERM DISCUSSION FOLLOWS. TUESDAY THROUGH THURSDAY...AN UPPER RIDGE WILL BUILD OFF THE COAST TUESDAY WITH A THERMAL TROUGH DEVELOPING AT THE COAST. THE MODELS DIFFER WITH THE DETAILS AFTER TUESDAY, BUT THE PATTERN REMAINS FAVORABLE FOR CONTINUED DRY AND WARM CONDITIONS. -PETRUCELLI && .MFR WATCHES/WARNINGS/ADVISORIES... OR...FLASH FLOOD WATCH THROUGH THIS EVENING FOR ORZ030-031. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS EVENING FOR ORZ022. CA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR CAZ080>085. PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ350-356-370-376. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS EVENING FOR PZZ350-356-370. GALE WARNING UNTIL 11 PM PDT THIS EVENING FOR PZZ356-376. GALE WATCH FROM SATURDAY MORNING THROUGH SUNDAY EVENING FOR PZZ376. $$
AREA FORECAST DISCUSSION
NWS MEDFORD OR
339 AM PDT FRI MAY 6 2016 .DISCUSSION...A MOIST AND UNSTABLE AIR MASS CONTINUES OVER MUCH OF THE FORECAST AREA TODAY...AND WILL HELP GENERATE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS...PRIMARILY FOCUSED OVER NORTHERN CALIFORNIA AND FROM THE CASCADES EASTWARD. THE CUTOFF LOW THAT DOESN`T QUIT REMAINS OVER SOUTHERN CALIFORNIA...SLOWLY MOVING TO THE EAST AND FEEDING THE AREA WITH DEEP MOISTURE AND DISTURBANCES FROM THE SOUTHEAST. THE INTERSECTION OF DEEP MOISTURE...INSTABILITY...AND FAVORABLE DYNAMICS WILL BE MOST PROMINENT IN EASTERN SISKIYOU...MODOC...AND LAKE COUNTIES TODAY. THE WRF ARW AND NMM SHOW STORMS AND HEAVY RAINFALL FROM MOUNT SHASTA EASTWARD TO ALTURAS AND NORTHEAST TO LAKEVIEW THIS AFTERNOON AND EVENING AS SHORTWAVE ENERGY MOVES IN FROM THE EAST PER THE NAM AND SREF MODEL OUTPUT. THE LATEST HRRR OUTPUT IS SUGGESTING SIMILAR. GIVEN CURRENT SNOW DEPTH OVER THE WARNER MOUNTAINS OF 62 INCHES PER DISMAL SWAMP SNOTEL...AND FORECAST SNOW LEVELS OF 9500 FEET...THIS DEFINITELY PROVIDES THE POTENTIAL FOR RAPID SNOW MELT AND FLASH FLOODING. A FLASH FLOOD WATCH CONTINUES FOR THE SOUTHERN HALF OF SISKIYOU COUNTY...MODOC...EXTREME EASTERN KLAMATH...AND MOST OF LAKE COUNTY. PRECIPITABLE WATER VALUES IN THE TOP 10 PERCENT FOR THIS TIME OF YEAR ALSO SUPPORT THE FFA AREA. THE WESTERN FRINGES OF THIS HAZARD AREA ARE LESS LIKELY TO SEE ANY HEAVY RAIN PROBLEMS BUT HAVE LEFT THE AREA INTACT FROM THE PREVIOUS ISSUANCE GIVEN THE UNCERTAINTY OF EXACT HEAVY RAIN LOCATIONS...AND WITH LATEST HRRR OUTPUT LINING UP PRETTY NICELY WITH THE HAZARD AREA. ADDITIONALLY...THE STORM PREDICTION CENTER HAS MAINTAINED A MARGINAL RISK FOR SEVERE STORMS OVER MODOC AND SOUTHERN LAKE COUNTIES. EASTERN SISKIYOU COUNTY ALSO FEATURES A CHANCE FOR SEVERE THUNDERSTORMS WITH FORECAST MOST UNSTABLE CAPES OF 2000+ J/KG, LI VALUES -4 TO -6, AND 0-6KM BULK SHEAR VALUES OF 30+KT. STRONG WINDS, HAIL, AND HEAVY RAIN ARE ALL A POSSIBILITY TODAY. LATEST SATELLITE IMAGERY SHOWS THAT THE DAY SHOULD START OUT SUNNY IN MANY PLACES EAST OF THE CASCADES...WHICH WILL YIELD UNINHIBITED SURFACE HEATING AND POTENTIALLY MAX OUT THE INSTABILITY THIS AFTERNOON. INSTABILITY DIMINISHES TONIGHT AND SHOWERS AND THUNDERSTORMS FOLLOW SUIT. ON SATURDAY A DRYING AIR MASS WEST OF THE CASCADES WILL YIELD SUNNY AND WARM CONDITIONS WHILE THUNDERSTORMS REMAIN POSSIBLE IN MODOC COUNTY. TEMPERATURES WILL BE ABOUT 10 DEGREES ABOVE NORMAL WEST OF THE CASCADES. BY SUNDAY COOL AND DRY NORTHWEST FLOW ALOFT ELIMINATES THE CHANCE FOR SHOWERS OVER THE VAST MAJORITY OF THE FORECAST AREA...WHILE A DEEPENING MARINE LAYER COULD BRING DRIZZLE TO THE COAST. ON MONDAY A WARM TREND BEGINS THAT WILL LAST INTO THE MIDDLE OF THE WEEK AT LEAST...WITH TEMPERATURES MONDAY EXPECTED TO BE A FEW DEGREES ABOVE NORMAL. A PORTION OF THE PREVIOUS LONG-TERM DISCUSSION FOLLOWS. TUESDAY THROUGH THURSDAY...AN UPPER RIDGE WILL BUILD OFF THE COAST TUESDAY WITH A THERMAL TROUGH DEVELOPING AT THE COAST. THE MODELS DIFFER WITH THE DETAILS AFTER TUESDAY, BUT THE PATTERN REMAINS FAVORABLE FOR CONTINUED DRY AND WARM CONDITIONS. -PETRUCELLI && .AVIATION...FOR THE 06/06Z TAF CYCLE...THE MAIN CONCERN THROUGH THIS EVENING WILL BE THUNDERSTORMS. THUNDERSTORMS ARE LIKELY TO BE SCATTERED TO NUMEROUS AND MORE LIKELY TO BE STRONG THIS AFTERNOON AND EVENING. THESE THUNDERSTORMS WILL BE SLOW MOVING AND PRODUCE MODERATE TO HEAVY RAIN AND THEY MAY PRODUCE GUSTY OUTFLOW WINDS, AND HAIL. THE BEST CHANCE THIS EVENING WILL BE OVER THE SOUTHERN OREGON CASCADE FOOTHILLS...CASCADES AND WESTERN AND CENTRAL SISKIYOU COUNTY WITH A SECONDARY FOCUS OVER MODOC AND LAKE COUNTIES. THUNDERSTORMS TODAY ARE EXPECTED TO BE MOST NUMEROUS EAST OF THE CASCADES ALTHOUGH ISOLATED STORMS MAY DEVELOP IN SOUTHWEST OREGON AND WESTERN SISKIYOU COUNTY. THERE WILL BE A MIX OF MVFR AND VFR CIGS THIS MORNING WITH AREAS OF MOUNTAIN OBSCURATIONS. CONDITIONS WILL IMPROVE TO WIDESPREAD VFR DURING LATE THIS MORNING BUT SHOWERS AND THUNDERSTORMS DEVELOPING LATE MORNING THROUGH THE EVENING WILL ONCE AGAIN CREATE AREAS OF MVFR WITH POTENTIALLY HAZARDOUS CONDITIONS. -DW/CC && .MARINE...UPDATED 830 PM PDT THU 5 MAY 2016...OFFSHORE HIGH PRESSURE AND INLAND LOW PRESSURE WILL PRODUCE PERSISTENT GUSTY NORTHERLY WINDS AND STEEP TO VERY STEEP SEAS THROUGH THIS EVENING. THE STRONGEST WINDS AND HIGHEST SEAS WILL OCCUR OVER THE OUTER WATERS SOUTH OF CAPE BLANCO. WINDS AND SEAS WILL REACH A PEAK THIS AFTERNOON...THEN GUSTY NORTH WINDS WILL CONTINUE AND SEAS ARE LIKELY TO REMAIN STEEP TO VERY STEEP THROUGH THE WEEKEND. AS A RESULT...A GALE WATCH HAS BEEN FOR THE OUTER WATERS SOUTH OF CAPE BLANCO FROM LATE SATURDAY MORNING THROUGH SUNDAY EVENING. CONFIDENCE IS MODERATE AS THE MAJORITY BUT NOT ALL OF THE MODELS HAVE TRENDED SLIGHTLY STRONGER WITH WEEKEND WINDS...ESPECIALLY ON SUNDAY. WINDS AND SEAS WILL BEGIN TO TREND WEAKER ON MONDAY AND ARE EXPECTED TO DIMINISH INTO WEDNESDAY. -DW/CC && .MFR WATCHES/WARNINGS/ADVISORIES... OR...FLASH FLOOD WATCH THROUGH THIS EVENING FOR ORZ030-031. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS EVENING FOR ORZ022. CA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR CAZ080>085. PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ350-356-370-376. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS EVENING FOR PZZ350-356-370. GALE WARNING UNTIL 11 PM PDT THIS EVENING FOR PZZ356-376. GALE WATCH FROM SATURDAY MORNING THROUGH SUNDAY EVENING FOR PZZ376. $$ NSK/MAP/CC
AREA FORECAST DISCUSSION...UPDATED
NWS CHEYENNE WY
542 AM MDT FRI MAY 6 2016 .UPDATE...FOR THE EARLY MORNING AVIATION FORECAST PACKAGE UPDATE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 401 AM MDT FRI MAY 6 2016 AN EXTREMELY ACTIVE PERIOD OF WEATHER OVER THE NEXT FEW DAYS WITH AT LEAST SOME POTENTIAL FOR SEVERE THUNDERSTORMS...FLASH FLOODING...AND ACCUMULATING MOUNTAIN SNOW. MORNING WATER VAPOR AND OBJECTIVE UPPER- AIR ANALYSIS REVEAL AN IMPRESSIVE OMEGA BLOCK ENCOMPASSING VIRTUALLY ALL OF THE LOWER 48. HIGH-AMPLITUDE RIDGING OVER THE GREAT PLAINS IS EXPECTED TO BREAK DOWN OVER THE NEXT 12 HOURS...BUT EXPECT VERY SLOW PROGRESSION OF THE SOUTHWESTERN US LOW GIVEN THE CURRENT LARGE SCALE BLOCKING PATTERN IN PLACE. SOUTHWEST FLOW ALOFT IS ALREADY INCREASING OVER THE CWA THIS AM WITH DEEP MOISTURE STREAMING NORTHWARD. WE WILL NOT SEE AS MUCH SUN AS WE HAVE OVER THE LAST FEW DAYS...BUT EXPECT ANOTHER MILD AFTERNOON WITH MODELS STILL SHOWING H7 TEMPS BETWEEN +8 AND +10 DEG C. IT WILL ALSO BE A WARM START TO THE DAY WITH CHEYENNE SITTING AT 53 DEGREES AS OF 3 AM MDT. WEAK SURFACE CYCLOGENESIS WILL OCCUR OVER NORTHEASTERN CO TODAY...RESULTING IN LOW-LEVEL UPSLOPE ALONG AND EAST OF THE LARAMIE RANGE HEADING INTO THIS AFTERNOON. LOW-LEVEL MOISTURE IS EXPECTED TO INCREASE WITH DEW POINTS IN THE 40S TO NEAR 50. WARM TEMPERATURES AT THE SURFACE WILL PROMOTE STEEP LAPSE RATES...POSSIBLY YIELDING CAPES AROUND 500-1000 J/KG AREAWIDE. FORECAST SOUNDINGS LOOK FAVORABLE FOR STRONG TO LOCALLY SEVERE CONVECTION...SO ADDED MENTION OF SMALL HAIL AND GUSTY WINDS FOR ALL ZONES THIS AFTERNOON. THE 06Z DY1 CONVECTIVE OUTLOOK FROM SPC HAS MUCH OF THE AREA IN A MARGINAL RISK. A PIECE OF MID-LEVEL VORT ENERGY IS PROGGED TO ROTATE ACROSS SOUTHEAST WYO LATE TONIGHT...BETWEEN 00Z AND 12Z SAT. BELIEVE THIS WILL INTERACT WITH A PRONOUNCED FRONTAL BOUNDARY AND DEEP UPSLOPE FLOW TO PRODUCE AN AREA OF MODERATE TO HEAVY PRECIPITATION OVER OUR NORTHERN ZONES...SO WENT AHEAD AND INTRODUCED CATEGORICAL POPS PER COORDINATION WITH UNR. BIG CHALLENGES WITH THE FORECAST FOR SATURDAY. MODELS SHOW THE UPPER LOW CENTERED OVER THE FOUR CORNERS WITH ONE OR MORE SIGNIFICANT VORT LOBES AFFECTING THE CWA...THE STRONGER OF WHICH APPEARS TO ARRIVE IN THE LATE AFTERNOON/EVENING. STRONG DYNAMIC SUPPORT IS LIKELY THROUGH THE DAY WITH CYCLOGENESIS OVER NORTHEAST CO REINFORCING UPSLOPE FLOW AND UPPER-LEVEL DIVERGENCE IN THE LEFT EXIT REGION OF A 100-110 KNOT H25 JET OVER SOUTHEAST CO. SEVERE THUNDERSTORMS ARE STARTING TO LOOK LIKE MORE OF A THREAT...MAINLY IN THE CYS-TOR-SNY TRIANGLE AND AREAS TO THE SOUTH AND EAST. WOULD LIKE TO SEE THE POSITION OF THE SURFACE LOW FARTHER NORTHWEST FOR A BIG OUTBREAK...BUT NONETHELESS THIS DOES SUPPORT MOIST EASTERLY SFC FLOW VEERING TO THE SOUTHEAST AT H7 WHICH YIELDS SHEAR PROFILES FAVORABLE FOR SUPERCELLS. BOTH THE GFS AND NAM SHOW 1500-2500 J/KG OF SBCAPE AND EXCELLENT 0-1 KM EHI GIVEN LOW-LVL SHEAR IN PLACE. SLIGHT RISK FROM SPC NOW INCLUDES I80 BETWEEN SIDNEY AND CHEYENNE...SO DECIDED TO ADD MENTION OF SEVERE. CIPS ANALOGS ARE CONSISTENT WITH SEVERAL NORTHEAST COLORADO TORNADO EVENTS...SO WOULD NOT BE SURPRISED TO SEE AN ISOLATED TORNADO OR TWO NEAR THE COLORADO BORDER ON SATURDAY. IN ADDITION TO THE RISK FOR SEVERE THUNDERSTORMS...A MORE WIDESPREAD THREAT FOR VERY HEAVY RAIN IS EXPECTED. DEEP MOISTURE AND IMPRESSIVE LARGE SCALE DYNAMICS WILL BE IN PLACE THROUGH THE NIGHT AS THE UPPER LOW WILL BE SLOW MOVING DUE TO A REX BLOCK. ABSOLUTELY NO DOUBT THAT THUNDERSTORMS ON SATURDAY/SATURDAY NIGHT WILL BE VERY EFFICIENT RAIN PRODUCERS WITH PWATS OF 0.5 TO 1.0 INCH BEING WELL ABOVE CLIMO. SOME CONCERN FOR TRAINING CONVECTION AS WELL. THE PRIMARY ISSUE HERE WILL LIKELY BE OVER THE HIGHER TERRAIN WITH AN ENHANCED LIKELIHOOD FOR AN ACCELERATED SNOWMELT AND FLASH FLOODING OF CREEKS/STREAMS. GAVE SOME CONSIDERATION TO A FLASH FLOOD WATCH...BUT WE DECIDED TO LET THE DAY SHIFT TAKE ANOTHER LOOK AND SEE IF THEY CAN NARROW DOWN THE SPECIFIC THREAT AREAS. WPC HAS MUCH OF OUR CWA IN A SLIGHT RISK FOR EXCESSIVE RAINFALL ON SATURDAY...SO FULLY EXPECT THAT FLOOD AND/OR FLASH FLOOD WATCHES WILL BE NECESSARY SOON. BY LATE SATURDAY NIGHT...WBZ HEIGHTS FINALLY DROP BELOW 10K FEET WHICH WOULD SUGGEST MOUNTAIN SNOW. COULD SEE ADVISORY-LEVEL AMOUNTS IF THE CHANGEOVER OCCURS SOON ENOUGH OVER THE SNOWY AND SIERRA MADRE RANGES. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 401 AM MDT FRI MAY 6 2016 WET PATTERN CONTINUES INTO SUNDAY AS THE UPPER LOW ESSENTIALLY STALLS ACROSS SOUTHEAST WYOMING WITH HIGH CHANCE TO LIKELY POPS A FAIRLY GOOD BET ACROSS THE ENTIRE FORECAST AREA. CONCERNS FOR FLOOD POTENTIAL WILL CONTINUE INTO SUNDAY GIVEN COVERAGE OF RAIN BUT COOLER TEMPERATURES SHOULD MEAN MORE SNOW IN THE HIGHER ELEVATIONS VERSUS RAIN BY LATE IN THE WEEKEND. THE AIRMASS WILL BE A BIT MORE STABILIZED ON SUNDAY DUE TO COOLER BOUNDARY LAYER CONDITIONS...HOWEVER WE STILL EXPECT TO SEE THE POTENTIAL FOR ISOLATED THUNDERSTORMS IN THE AFTERNOON TO EARLY EVENING HOURS. THE UPPER LOW FINALLY KICKS OUT TO THE NORTHEAST LATE MONDAY WITH A DOWNWARD TREND IN POPS EXPECTED ACROSS THE SOUTHERN ZONES TUESDAY WITH CHANCE POPS FOR SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE NORTHERN ZONES AHEAD OF THE NEXT APPROACHING UPPER TROUGH MOVING DOWN FROM MONTANA. THAT TROUGH MOVES EAST BY THURSDAY WITH SLIGHT CHANCE POPS EXPECTED GOING INTO LATE WEEK. OVERALL NEXT WEEK LOOKS TO BE COOLER THAN WHAT WE HAVE SEEN THE LATTER PART OF THIS WEEK WITH DAILY HIGH TEMPS GENERALLY IN THE 40S-50S WEST AND 60S EAST. ELEVATIONS ABOVE 9500 FT LOOK TO SEE HIGHS IN THE MID 30S TO AROUND 40 THROUGH THE WEEK...COOL ENOUGH TO SLOW THE SNOWMELT PROCESS A BIT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 542 AM MDT FRI MAY 6 2016 FOLLOWED TREND AS DEPICTED BY HRRR THIS PACKAGE IN BRINGING SHOWERS AND ISOLATED THUNDERSTORMS UP INTO SE WYOMING MID TO LATE AFTERNOON THEN INTO THE NEBRASKA PANHANDLE BY EARLY EVENING. CEILINGS AND VISIBILITIES PREVAILING VFR THROUGH LATE AFTERNOON INTO THE EVENING HOURS WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS PASSING ACROSS THE REGION. LOWERED CEILINGS FOR SCOTTSBLUFF, CHEYENNE, LARAMIE AND RAWLINS DOWN TO MVFR AFTER 06Z WHERE GREATER COVERAGE OF SHOWERS WILL BE AS DEEPER MOISTURE MOVES UP FROM THE SOUTH. && .FIRE WEATHER... ISSUED AT 401 AM MDT FRI MAY 6 2016 COOLER AND WETTER PATTERN STILL PROJECTED TO SET UP ACROSS SE WYOMING AND THE WESTERN NEBRASKA PANHANDLE THROUGH THE WEEKEND. PATTERN BECOMES A BIT LESS ACTIVE FOR SHOWERS AND THUNDERSTORMS BY MID WEEK WITH PROJECTED CONDITIONS EXPECTED TO REMAIN WELL ABOVE ANY CRITICAL THRESHOLDS FOR FIRE WEATHER CONCERNS IN THE FORSEEABLE FUTURE. && .HYDROLOGY... ISSUED AT 401 AM MDT FRI MAY 6 2016 WARM TEMPERATURES WILL CONTINUE TODAY WITH AFTERNOON HIGHS LIKELY IN THE 50S IN THE HIGH ELEVATIONS OF THE SNOWY/SIERRA MADRE RANGES. MTN CREEKS AND STREAMS WILL CONTINUE TO SEE NOTABLE RISES IN THE NEXT 24 TO 48 HOURS. WIDESPREAD THUNDERSTORMS COULD PRODUCE HEAVY RAIN TODAY AND SATURDAY. RAIN ON SNOW COULD YIELD ACCELERATED SNOWMELT AND LEAD TO FLASH FLOODING...ESPECIALLY OF MOUNTAIN CREEKS/STREAMS. THERE MAY ALSO BE A THREAT FOR LOCALIZED FLASH FLOODING OVER THE PLAINS. FLASH FLOOD WATCHES MAY BECOME NECESSARY SOON. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...CLH LONG TERM...JG AVIATION...JG FIRE WEATHER...JG HYDROLOGY...CLH
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
910 AM MST FRI MAY 6 2016 .SYNOPSIS... A LARGE PACIFIC LOW PRESSURE SYSTEM WILL MOVE ACROSS THE DESERT SOUTHWEST OVER THE NEXT FEW DAYS. THIS SYSTEM WILL BRING A CHANCE FOR SHOWERS...PLUS POTENTIAL FOR THUNDERSTORMS...ALONG WITH MUCH COOLER CONDITIONS. BEST CHANCES FOR RAIN WILL BE TODAY INTO EARLY SATURDAY. THE LOW PRESSURE SYSTEM WILL BEGIN TO MOVE EAST SUNDAY...FOLLOWED BY DRY AND MUCH WARMER WEATHER NEXT WEEK. && .DISCUSSION... SEVERAL DIFFERENT SYNOPTIC AND MESOSCALE PROCESSES ONGOING THIS MORNING PER SATELLITE IMAGERY AND OBJECTIVE ANALYSIS. FIRST OVER GILA COUNTY...A NARROW CORRIDOR OF ISENTROPIC LIFT AND H7-H8 FRONTOGENTICAL FORCING WAS LIFTING MARGINAL MOISTURE INTO A REGION OF STEEPER MIDLEVEL LAPSE RATES. SEVERAL ACCAS BANDS WITH EMBEDDED DEEPER CONVECTIVE ELEMENTS WILL CONTINUE TO STREAM NORTH THIS MORNING OVER THE MOGOLLON RIM...HOWEVER LARGELY BE A NON-PLAYER WITHIN THE LOCAL FORECAST FOR THE REMAINDER OF THE DAY. SECONDLY...A SFC-H8 FRONTAL BOUNDARY WAS EVIDENT THROUGH FAR WESTERN ARIZONA WITH MODEST +10C H9 DEWPOINTS BEING PULLED NORTH AHEAD OF THIS FRONT. CONCURRENT WITH THIS MOISTURE ADVECTION...A POCKET OF 0- 3KM MLCAPE ABOVE 100 J/KG (AND TOTAL MUCAPE IN EXCESS OF 500 J/KG) WAS ANALYZED THROUGH MUCH OF LA PAZ COUNTY. UPSTREAM...A LOBE OF VORTICITY WAS LIFTING THROUGH THE SAN DIEGO AREA WITH WINDWARD SIDE SHOWERS BEING WRUNG OUT OVER HIGHER TERRAIN. HOWEVER...THIS LARGER SCALE SYNOPTIC ASCENT WILL GRADUALLY OVERSPREAD THE AREA OF INCREASING INSTABILITY THIS AFTERNOON...AND MORE ROBUST CONVECTIVE DEVELOPMENT IS MOST LIKELY ALONG AND JUST EAST OF THE COLORADO RIVER VALLEY THROUGH THE DAYLIGHT HOURS. HRRR AND OTHER HIGH RESOLUTION NMM CORES SEEM TO CAPTURE THIS EVOLUTION BEST...AND HAVE HEDGED MOST OF THE SHORT TERM FORECAST IN THIS DIRECTION. && .PREVIOUS DISCUSSION... /524 AM MST FRI MAY 6 2016/ TODAY THROUGH SUNDAY... THE LOW PRESSURE SYSTEM WHICH BROUGHT THE WINDS AND THE BEGINNING OF A COOLING TREND IS CENTERED JUST OF SANTA BARBARA EARLY THIS MORNING. WATER VAPOR IMAGERY SHOWS MULTIPLE VORT LOBES WITHIN THE SYSTEM. AT THE SURFACE...ONE OF WHICH IS MOVING ASHORE INTO FAR SOUTHERN CALIFORNIA. A SURFACE LOW REMAINS CENTERED OVER THE MOHAVE DESERT. MODELS CONTINUE TO DEPICT THE UPPER LOW/UPPER TROUGH TRACKING EASTWARD TODAY AND SATURDAY THEN BEGIN EXITING SUNDAY. IN THE PROCESS...THERE WILL BE A SERIES OF VORT LOBES MOVING THROUGH FOR SOME DYNAMICAL ASCENT AT TIMES PLUS COLDER AIR ALOFT FOR SOME DESTABILIZATION. THERE MAY ALSO BE SOME ADDED DYNAMICAL ASCENT TODAY ASSOCIATED WITH THE LEFT EXIT REGION OF THE JET. AS THE SYSTEM TRACKS EAST WITH TIME THE JET AXIS MOVES FURTHER AWAY. ONE OF THE AFOREMENTIONED VORT LOBES IS MOVING ASHORE INTO FAR SOUTHERN CALIFORNIA. THIS FEATURE IS NOT INITIALIZED WELL BY THE LATEST MODELS. BUT IR IMAGERY SHOWS COLD CLOUD TOPS AND THERE IS EVEN SOME ISOLATED LIGHTNING BEING DETECTED WITHIN THE ASSOCIATED CLOUDINESS. THIS FEATURE WILL AFFECT MAINLY WESTERN PORTIONS OF THE FORECAST AREA TODAY BUT THERE WILL ALSO BE SOME STEEPENING LAPSE RATES EVERYWHERE AND THUS AN UPRAMPING OF POPS TODAY. HI-RES MODELS ARE A MIXED BAG AS TO THE ONSET OF SHOWERS OVER SOUTH-CENTRAL ARIZONA TODAY. SOME OF THEM INDICATE A BAND OF SHOWERS DEVELOPING THIS MORNING...POSSIBLY DUE TO THE SURFACE TROUGH AND ASSOCIATED LOWER LEVEL CONVERGENCE. THERE IS ALSO SOME UPPER LEVEL DIFLUENCE/DIVERGENCE THERE AS WELL. THE MAIN THEME OF THE MODELS IN TERMS OF PRECIP POTENTIAL IS THAT CHANCES INCREASE FROM WEST TO EAST AS THE DAY WEARS ON AND PEAKS EAST OF THE LOWER COLORADO RIVER VALLEY TONIGHT AS A VORT LOBE MOVES THROUGH. POPS TREND DOWN DOWN SATURDAY BEHIND THE EXITING LOBE BUT DONT GO AWAY ENTIRELY DUE TO LINGERING MOISTURE AND ANOTHER VORT LOBE...THOUGH THAT ONE TRACKS MOSTLY SOUTH. YET ANOTHER ONE COMES THROUGH SUNDAY BUT ON THE BACK SIDE OF THE LOW AS THE SYSTEM IS SHIFTING NORTHEASTWARD. PEAK PRECIPITABLE WATER VALUES ARE NEAR 1 INCH AT THE COAST BUT WITH RAIN SHADOWING WE WILL SEE LESS AND THUS NOT LOOKING FOR A BIG PRECIP EVENT...BUT CONSIDERING WE ARE GETTING INTO THE VERY DRIEST TIME OF YEAR...IT WILL BE NOTABLE. THERE WILL ALSO BE A THREAT OF THUNDERSTORMS. WHILE CAPE IS LOOKING MODEST...JUST ENOUGH TO UPGRADE MENTION TO CHANCE IN SOME AREAS...SLIGHT CHANCE ELSEWHERE. AS FOR TEMPS...CONTINUED COLD AIR ADVECTION WILL MAKE FOR MUCH COOLER CONDITIONS TODAY OVER SOUTH-CENTRAL ARIZONA...AS MUCH AS 20 DEGREES. THERE WILL BE LESS COOLING FURTHER WEST BECAUSE OF ALREADY HAVING COOLED INTO THE 80S YESTERDAY. THUS...HIGHS ON THE LOW DESERTS WILL BE IN THE 70S FRIDAY AND SATURDAY THEN WARMING AT LEAST A FEW DEGREES ON SUNDAY. MONDAY THROUGH THURSDAY... PACIFIC RIDGING SLOWLY BUILDS INTO THE WESTERN STATES DURING THE NEXT WORKWEEK FOR A WARMING TREND. EXPECT DESERTS TO FLIRT WITH 100 AGAIN BY THURSDAY. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL... FLOW WILL VEER THROUGHOUT THE DAY AHEAD OF A LOW PRESSURE SYSTEM. HOWEVER...A PERIOD OF 10-15 KT CROSS-WINDS IS LIKELY THIS MORNING AT KPHX. BREEZY SOUTHWESTERLY WINDS ARE ALSO ANTICIPATED THIS AFTERNOON...THOUGH THEY WILL BE WEAKER THAN THOSE OBSERVED THURSDAY WITH GUSTS GENERALLY AROUND 25 KT. SCATTERED SHOWERS ARE EXPECTED TO MOVE INTO THE PHOENIX AREA THIS EVENING...BEFORE DISSIPATING BEFORE MIDNIGHT. OTHERWISE...CLOUD BASES WILL GENERALLY HOVER BETWEEN 5K AND 8K FT...PERHAPS BECOMING BKN TOWARDS SATURDAY MORNING. SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... BREEZY SOUTH AND SOUTHWESTERLY FLOW WILL PERSIST AHEAD OF A PACIFIC LOW PRESSURE SYSTEM. SCATTERED SHOWERS ARE ALSO EXPECTED TO DEVELOP LATER THIS MORNING AND EARLY THIS AFTERNOON AT KIPL/KBLH. A BRIEF THUNDERSTORM IS ALSO POSSIBLE...THOUGH THE POTENTIAL FOR HAZARDS SUCH AS GUSTY WINDS AND BLOWING DUST IS LOW. IMPROVING CONDITIONS ARE LIKELY BY 02Z SATURDAY AS THE ACTIVITY SHIFTS TO THE EAST. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... SUNDAY THROUGH THURSDAY... THE SLOW-MOVING WEATHER SYSTEM WILL WEAKEN AND MOVE NORTHEASTWARD OUT OF THE REGION SUNDAY. NEVERTHELESS...A FEW SHOWERS WILL BE POSSIBLE SUNDAY...MAINLY NORTH AND EAST OF PHOENIX. THEREAFTER...A WARMING AND DRYING TREND WILL TAKE PLACE AS HIGH PRESSURE RETURNS TO THE DESERT SOUTHWEST. ABOVE NORMAL TEMPERATURES ARE LIKELY BY TUESDAY OR WEDNESDAY...PERHAPS REACHING THE 100 DEGREE MARK AGAIN IN THE LOWER DESERTS. DESPITE THE LOW RHS...FIRE DANGER WILL GENERALLY REMAIN LOW THROUGH THE WEEK WITH LIGHT WINDS AND RELATIVELY MOIST FUELS. && .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...MO/AJ AVIATION...HIRSCH FIRE WEATHER...HIRSCH
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
155 PM PDT FRI MAY 6 2016 .SYNOPSIS...A BROAD UPPER LEVEL LOW NOW CENTERED JUST OFF OF THE SOUTHERN CALIFORNIA COAST WILL SHIFT SLOWLY EASTWARD AND INLAND TODAY. BANDS OF MOISTURE ROTATING AROUND IT WILL MAINTAIN SHOWER CHANCES OVER OUR DISTRICT THROUGH SATURDAY EVENING. THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AS WELL...PRIMARILY MORE INLAND AREAS. PRECIP CHANCES WILL DIMINISH SATURDAY NIGHT AND SUNDAY MORNING...WITH DRY CONDITIONS THEN EXPECTED TO PREVAIL THROUGH THE REMAINDER OF THE FORECAST PERIOD. A GRADUAL WARMING TREND IS EXPECTED FOR THE FIRST HALF OF NEXT WEEK AS A RIDGE OF UPPER LEVEL HIGH PRESSURE BUILDS OVER THE WEST COAST. && .DISCUSSION...AS OF 2:00 PM PDT FRIDAY...MOISTURE ROTATING AROUND AN AREA OF LOW PRESSURE OVER SOUTHERN CALIFORNIA IS CURRENTLY MOVING THROUGH OUR CWA. WORTH NOTING THAT THE RUNS OF THE HRRR EARLIER THIS MORNING SO FAR HAVE DONE A GOOD JOB WITH BRINGING THE MOISTURE INTO OUR CWA FROM STO`S. AMOUNTS HAVE BEEN FAIRLY LIGHT SO FAR WITH MANY PLACES UNDER 1/4". RAIN WILL CONTINUE TO TRACK TO THE SOUTH INTO MONTEREY AND SAN BENITO COUNTIES. COULD ALSO SEE A FEW THUNDERSTORMS. IN FACT, ONE CELL FIRED UP OVER FAR SOUTHERN SAN BENTIO COUNTY THIS AFTERNOON. A SECOND ROUND OF RAIN IS FORECAST FOR TOMORROW AS ANOTHER SLUG OF MOISTURE ROTATES AROUND THE LOW. MODELS SHOW SIMILAR VALUES AND FAIRLY CLOSE TIMING FOR TOMORROW COMPARED TO TODAY WITH ANOTHER ROUND OF UP TO 1/4" FOR MOST URBAN SPOTS. INSTABILITY DOES NOT LOOK AS FAVORABLE FOR THUNDERSTORMS COMPARED TO TODAY, HOWEVER AN ISOLATED CELL OR TWO FOR PARTS WELL INLAND CANNOT BE RULED OUT. SHOWERS WILL COME TO AN END SATURDAY NIGHT AS THE LOW TRACKS INTO THE FOUR CORNER`S REGION. A RIDGE OF HIGH PRESSURE WILL THEN REBUILD TO THE WEST COAST THROUGH NEXT WEEK. THIS WILL HELP TO PUSH TEMPS BACK TO NORMAL TO ABOVE LEVELS. BY THE MIDDLE OF NEXT WEEK MOST HIGHS WILL BE IN THE 70S TO THE MID 80S. NO REAL SIGNS OF ORGANIZED PRECIPITATION FOR ALL OF NEXT WEEK. && .AVIATION...AS OF 10:55 AM PDT FRIDAY...FOR 18Z TAFS. UPPER LOW IN VICINITY BRINGING GENERALLY UNSETTLED WEATHER TO THE REGION. WRAP AROUND RAIN SHOWERS WILL MOVE THROUGH THE REGION TODAY AND INTO SATURDAY BRINGING PERIODS OF -SHRA AND MVFR CIGS. SKIES WILL BE CHAOTIC WITH FRACTURED DECKS AT VARYING FLIGHT LEVELS FROM 800 FT TO 11000 FT. THUS VFR TO IFR CIGS WILL BE POSSIBLE... WITH MOSTLY VFR/MVFR CIGS TO BE EXPECTED. OVERALL LOW CONFIDENCE. WINDS GENERALLY 15 KT OR LESS. VICINITY OF KSFO... INTERMITTENT MVFR/VFR OSCILLATING CIGS THRU THE DAY WITH VCSH/-SHRA FROM WRAP AROUND SHOWERS. ONSHORE WINDS UP TO 15KT DURING THE AFTERNOON. SFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY TERMINALS...INTERMITTENT MVFR/VFR OSCILLATING CIGS THRU DAY WITH VCSH/-SHRA FROM WRAP AROUND SHOWERS. ONSHORE WINDS UP TO 12 KT DURING AFTERNOON. WINDS NEAR KSNS GUSTING TO AROUND 20 KT AFTER 14Z SAT. && .MARINE...AS OF 10:47 AM PDT FRIDAY...A LOW PRESSURE STORM SYSTEM WILL SHIFT FARTHER INLAND TODAY BUT CONTINUE TO SPREAD RAIN SHOWERS OVER THE COASTAL WATERS. WINDS WILL BE SPLIT... WITH BREEZY NORTHERLY WINDS ACROSS THE NORTHERN OUTER WATERS AND LIGHT SOUTHERLY WINDS ALONG MUCH OF THE COAST AND THE SOUTHERN WATERS. SEAS WILL CONTINUE TO BE LIGHT THROUGH SATURDAY. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM && $$ PUBLIC FORECAST: BELL/BLIER AVIATION: DRP MARINE: DRP VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK AND TWITTER AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA
  [top] Area Forecast Discussion National Weather Service Sacramento CA 153 PM PDT FRI MAY 6 2016 .SHORT TERM DISCUSSION... .Synopsis... Another day of showers Saturday then a drying trend with only a slight chance of showers Sunday. Temperatures warming into 90s next week. .Short Term Discussion... Clouds keeping instability down today and not nearly as much convection going today as yesterday. Biggest challenge is trying to figure out timing of the next wave of moisture. Both the GFS/NAM in pretty good agreement that this wave will rotate down into Sacramento area tonight after midnight. HRRR however suggesting it will come sooner, either way, should be another round of rain pushing across tonight and probably into Saturday morning. After the morning rain, instability not nearly as high Saturday afternoon, but enough around that there should be a few showers. Sunday...overall the energy from this weather system is shifting away from the area. Have kept a slight chance of showers in the valley and slightly higher in higher terrain, but overall a drier and warmer day. This drying and warming trend continues into Monday. Rasch .EXTENDED DISCUSSION (Tuesday THROUGH Friday) Warmer and dry pattern ahead for Northern California. A weak system is projected to clip the area on Tuesday, but this will bring only light showers to portions of the Sierra and southern Cascades. Upper ridge moves in late Tuesday and persists through extended period. High temperatures under ridge will be in the mid to upper 80s with some locations in the northern portions of Valley like Redding and Red Bluff reaching low 90s. Just beyond the extended period, models hint at ridge breaking down with trough moving in during the weekend. Models disagree this far in advance with how far south the trough digs and how quickly it moves through, which isn`t surprising. Either way, it could mean another chance of precip in the long term. Owen && .AVIATION... Upr low ovr SoCal with Ely flow alf ovr fcst area bcmg NEly tngt and Sat as low movs into Grt Basin. VFR conds ovr Intr NorCal nxt 24 hrs exc lcl MVFR poss in shwrs or tstms...mnly ovr fthls/mtns. SFC wnds genly blo 15 kts thru Sat exc gsty nr tstms. && .STO Watches/Warnings/Advisories... None. && $$
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1053 AM PDT FRI MAY 6 2016 .SYNOPSIS...A BROAD UPPER LEVEL LOW NOW CENTERED JUST OFF OF THE SOUTHERN CALIFORNIA COAST WILL SHIFT SLOWLY EASTWARD AND INLAND TODAY. BANDS OF MOISTURE ROTATING AROUND IT WILL MAINTAIN SHOWER CHANCES OVER OUR DISTRICT THROUGH SATURDAY EVENING. THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AS WELL...PRIMARILY MORE INLAND AREAS. PRECIP CHANCES WILL DIMINISH SATURDAY NIGHT AND SUNDAY MORNING...WITH DRY CONDITIONS THEN EXPECTED TO PREVAIL THROUGH THE REMAINDER OF THE FORECAST PERIOD. A GRADUAL WARMING TREND IS EXPECTED FOR THE FIRST HALF OF NEXT WEEK AS A RIDGE OF UPPER LEVEL HIGH PRESSURE BUILDS OVER THE WEST COAST. && .DISCUSSION...AS OF 9:00 AM PDT FRIDAY...SHOWERS EXPECTED TO RETURN TO OUR REGION SHORTLY. IN FACT HRRR IS FAIRLY BULLISH AND BRINGS AN AREA OF MOISTURE (WELL DEPICTED BY RADARS) TO MOST OF THE SF BAY REGION DOWN TO SANTA CRUZ AND SANTA CLARA COUNTY BY EARLY IN THE AFTERNOON. AFTER THAT SHOWERS CAN BE EXPECTED WITH ANOTHER ROUND OF RAIN FORECAST FOR TOMORROW. DID A MINOR UPDATE THIS MORNING TO THE FORECAST AND UPPED THE POPS FOR SATURDAY IN LIGHT OF LATEST GUIDANCE. ALSO ADDED A SLIGHT CHANCED FOR THUNDERSTORMS TO EASTERN PARTS OF THE CWA. RAINFALL AMOUNTS STILL FORECAST TO BE FAIRLY LIGHT WITH UNDER 1/4" IN MOST URBAN SPOTS. LOCAL RANGES COULD SEE UP TO 2/3". WILL UPDATE FORECAST TODAY AS NECESSARY BASED ON THE TRACK OF THE RAIN. .PREVIOUS DISCUSSION...LATEST KMUX RADAR DATA AND SURFACE OBS INDICATE DRY CONDITIONS NOW PREVAILING ACROSS MOST OF OUR DISTRICT...THOUGH WITH SOME SHOWERS HAVING JUST DEVELOPED OVER THE SOUTHERN SANTA LUCIA MTNS OF MONTEREY COUNTY. WATER VAPOR SATELLITE IMAGERY AND MODEL ANALYSIS SHOW A BROAD AND DIFFUSE UPPER LEVEL LOW NEAR THE SOUTHERN CALIFORNIA COAST...WITH ITS CENTER PRESENTLY IN THE VICINITY OF THE NORTHERN CHANNEL ISLANDS. THE SYNOPTIC SCALE WEATHER SITUATION FOR OUR AREA IS AN UNUSUAL ONE...WITH THE FLOW ALOFT ADVECTING IN A MOIST AND POTENTIALLY UNSTABLE AIR MASS FROM THE EAST. THE NEXT BAND OF CLOUDINESS IS SPREADING RAPIDLY WESTWARD INTO THE SF BAY AREA THROUGH THE MIDDLE OF THE CENTRAL VALLEY. THUS FAR HOWEVER...ASSOCIATED PRECIP HAS LARGELY BEEN CONFINED TO THE HIGHER ELEVATIONS OF THE SIERRA NEVADA WITH NEITHER KDAX NOR KMUX RADARS...OR SURFACE OBS...INDICATING ANY APPRECIABLE ASSOCIATED SHOWER ACTIVITY PRESENTLY MOVING TOWARDS US. AS A RESULT EXPECT THE DAY TO GET OFF TO A DRY START...AT LEAST THROUGH THE MORNING COMMUTE. THEREAFTER THOUGH CONFIDENCE DIMINISHES. MODEL PERFORMANCE IN GENERAL WITH THIS SYSTEM THUS FAR...IN TERMS OF TIMING AND LOCATION OF ASSOCIATED PRECIPITATION...HAS NOT BEEN PARTICULARLY IMPRESSIVE. AND EVEN IN THE SHORT TERM...WIDE VARIATION BETWEEN MODEL SOLUTIONS IN THIS RESPECT CONTINUES TO BE EVIDENT. THE NEW 06Z RUN OF THE GFS SHOWS PRECIP THIS AFTERNOON PRIMARILY CONFINED TO SANTA CLARA AND SAN BENITO COUNTIES...WHILE THE 06Z NAM SPREADS IT OVER ALMOST ALL OF OUR DISTRICT ASIDE FROM SONOMA COUNTY...THE LATEST (09Z) HRRR RUN STARTS THE SHOWER ACTIVITY IN THE LATE MORNING OVER THE NORTH BAY WITH IT THEN DIMINISHING AS IT MOVES SOUTHWARD THROUGH THE CENTRAL SF BAY AREA DURING THE AFTERNOON...AND THE LATEST AVAILABLE (00Z) OUTPUT FROM THE ECMWF MODEL FOCUSES IT ON THE FAR SE PORTION OF OUR CWA DURING THE AFTERNOON. AS A RESULT...VERY DIFFICULT TO NAIL DOWN DETAILS IN GRIDS AND FORECAST. THAT SAID HOWEVER...THERE IS MUCH BETTER AGREEMENT REGARDING THE GENERAL LARGER-SCALE PICTURE AND EVOLUTION. GOOD CONSENSUS THAT THE UPPER LEVEL LOW WILL TRACK GRADUALLY EASTWARD THROUGH FAR SOUTHERN CALIFORNIA AND INTO ARIZONA BY SUNDAY MORNING. BY THAT POINT ALL ASSOCIATED PRECIP SHOULD HAVE SHIFTED EASTWARD OF OUR DISTRICT...BUT UNTIL THEN SHOWER CHANCES WILL CONTINUE. THUNDERSTORMS WILL ALSO REMAIN POSSIBLE THROUGH THIS EVENING...PRIMARILY OVER THE MOUNTAINS AND MORE INLAND AREAS...AND THEN SHOULD DIMINISH AND COME TO AN END AS THE AIR MASS STABILIZES. FROM SUNDAY AFTERNOON THROUGH AT LEAST THE MIDDLE OF NEXT WEEK...DRY CONDITIONS AND A WARMING TREND ARE EXPECTED TO PREVAIL WITH GOOD LONGER RANGE MODEL AGREEMENT THAT AN UPPER LEVEL RIDGE WILL BUILD IN OVER THE WEST COAST. BOTH THE ECMWF AND GFS SIGNIFICANTLY RAISE 850 MB TEMPS AS THIS OCCURS...UP INTO THE 15C TO 17C RANGE BY WEDNESDAY AND THURSDAY WITH AFTERNOON HIGHS...AT LEAST INLAND AREAS...THEN PROJECTED TO REACH UP INTO THE 80S. && .AVIATION...AS OF 10:55 AM PDT FRIDAY...FOR 18Z TAFS. UPPER LOW IN VICINITY BRINGING GENERALLY UNSETTLED WEATHER TO THE REGION. WRAP AROUND RAIN SHOWERS WILL MOVE THROUGH THE REGION TODAY AND INTO SATURDAY BRINGING PERIODS OF -SHRA AND MVFR CIGS. SKIES WILL BE CHAOTIC WITH FRACTURED DECKS AT VARYING FLIGHT LEVELS FROM 800 FT TO 11000 FT. THUS VFR TO IFR CIGS WILL BE POSSIBLE... WITH MOSTLY VFR/MVFR CIGS TO BE EXPECTED. OVERALL LOW CONFIDENCE. WINDS GENERALLY 15 KT OR LESS. VICINITY OF KSFO... INTERMITTENT MVFR/VFR OSCILLATING CIGS THRU THE DAY WITH VCSH/-SHRA FROM WRAP AROUND SHOWERS. ONSHORE WINDS UP TO 15KT DURING THE AFTERNOON. SFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY TERMINALS...INTERMITTENT MVFR/VFR OSCILLATING CIGS THRU DAY WITH VCSH/-SHRA FROM WRAP AROUND SHOWERS. ONSHORE WINDS UP TO 12 KT DURING AFTERNOON. WINDS NEAR KSNS GUSTING TO AROUND 20 KT AFTER 14Z SAT. && .MARINE...AS OF 10:47 AM PDT FRIDAY...A LOW PRESSURE STORM SYSTEM WILL SHIFT FARTHER INLAND TODAY BUT CONTINUE TO SPREAD RAIN SHOWERS OVER THE COASTAL WATERS. WINDS WILL BE SPLIT... WITH BREEZY NORTHERLY WINDS ACROSS THE NORTHERN OUTER WATERS AND LIGHT SOUTHERLY WINDS ALONG MUCH OF THE COAST AND THE SOUTHERN WATERS. SEAS WILL CONTINUE TO BE LIGHT THROUGH SATURDAY. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM && $$ PUBLIC FORECAST: BELL/BLIER AVIATION: DRP MARINE: DRP VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK AND TWITTER AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1053 AM MDT FRI MAY 6 2016 .UPDATE... ISSUED AT 1053 AM MDT FRI MAY 6 2016 MADE SOME SLIGHT CHANGES TO THE COVERAGE OF SHOWERS THIS AFTERNOON OER THE MOUNTAINS...FOOTHILLS AND ADJACENT PLAINS BASED ON THE FORECASTS OF THE PAST SEVERAL RUNS OF THE RAP MODEL. MOST OF THE SHOWER ACTIVITY IS EXPECTED TO BE OVER THE MOUNTAINS AND FOOTHILLS...BUT A FEW STORMS MAY ALSO DEVELOP OVER THE I-25 URBAN CORRIDOR. GUSTY WINDS ARE GOING TO BE THE MAIN THREAT FROM THE STORMS THAT DEVELOP THIS AFTERNOON...ALTHOUGH MOUNTAIN AREAS COULD PICK UP A LITTLE RAIN AND SMALL HAIL TOO. THE PRIMARY BAND OF SHOWERS IS MOVING NORTHWARD OVER PARK COUNTY AT THE PRESENT TIME. ADDITIONAL SHOWER DEVELOPMENT AFTER PASSAGE OF THE FIRST BAND OF SHOWERS WILL BE LIMITED DUE TO THE WEAK SUBSIDENCE TRAILING THE SHORT WAVE THAT IS DRIVING THE SHOWER DEVELOPMENT. HOWEVER... THERE COULD BE ENOUGH AFTERNOON HEATING OVER THE MOUNTAINS FOR A FEW WEAK SHOWERS TO DEVELOP. IT LOOKS LIKE SHOWER ACTIVITY ACROSS THE EASTERN PLAINS IS GOING TO BE QUITE LIMITED EXCEPT NEAR THE WYOMING BORDER LATER TONIGHT. THIS WILL ALLOW FOR THE TEMPERATURES TO CLIMB NICELY INTO THE UPPER 70S AND LOWER 80S. THE OTHER CHANGE TO THE FORECAST WAS TO ADD BACK THE MENTION OF SEVERE THUNDERSTORMS ON THE PLAINS SATURDAY AFTERNOON. MORNING MODEL RUNS INDICATE THE FRONTAL BOUNDARY WILL BE SOMEWHERE OVER NORTHEAST COLORADO SATURDAY MORNING...PROBABLY ACROSS MORGAN...WELD AND LARIMER COUNTIES. MODEL SOUNDINGS IN THE GREELEY AREA SHOW MIDDAY CAPE VALUES IN EXCESS OF 2000 J/KG. FAVORABLE WIND SHEAR PROFILES ALSO LOOK LIKE THEY ARE GOING TO BE IN PLACE FOR STRONG THUNDERSTORM DEVELOPMENT BY EARLY AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 430 AM MDT FRI MAY 6 2016 THE DEEPENING TROUGH/CLOSED LOW TRACKING SLOWLY E-SEWRD ACROSS SOUTHERN CALIF IS BEGINNING TO EXERT ITS DOMINANCE ON FLOW AT ALL LEVELS AND WX AS FAR EAST AS THE SRN AND CNTRL ROCKIES. DEEP S-SWLY FLOW ON THE FRONT SIDE OF THIS TROUGH CONTINUES TO DIRECT MID AND HIGH-LEVEL MOISTURE UP INTO THE AREA AND LATER TODAY A SPOKE OF MID- LEVEL ENERGY AND SHEAR WHICH THE RAP AND OTHER MODELS INDICATE PASSING OVER NRN NEW MEXICO AT THIS TIME. EVEN WITH VARYING AMOUNTS OF HIGH CLOUDINESS THIS MORNING STRONG DIABATIC HEATING SHOULD MANAGE TO GENERATE 8-9C/KM BNDRY LAYER LAPSE RATES AND SFC BASED 600- 1200 J/KG CAPES ON THE PLAINS BY MIDDAY. WHILE THE WELL MIXED BOUNDARY LAYER APPEAR LACKING OF MOISTURE...MODELS INDICATE A GRADUAL INCREASE IN MID-LEVEL MOISTURE WITH INCREASING SELY MID- LEVEL FLOW IN ADVANCE OF THE SHORTWAVE DISTURBANCE SWINGING UP FROM SERN COLORADO. WHILE CONVECTIVE CLOUDS WILL BE ON THE INCREASE THIS AFTERNOON...MODELS DO NOT INDICATE MUCH IN THE WAY OF QPF ON THE PLAINS TODAY. INVERTED-V MODEL SOUNDINGS INDICATE A FAVORABLE SUB- CLOUD ENVIRONMENT FOR MICROBURST FORMATION THIS AFTERNOON EVEN AS MEAN LAYER PW VALUES CREEP UPWARD PRIOR TO PASSAGE OF THE U/A DISTURBANCE TIMED TO OCCUR AROUND 00Z IN THE DENVER AREA. AFTER 00Z/SAT...THE MICROBURST THREAT SHOULD QUICKLY DIMINISH FROM SOUTH TO NORTH WITH INFLUX OF DRIER MIX-LEVEL AIR BEHIND THE SHORTWAVE. THIS DRYING IS FORECAST TO CONTINUE EVEN NEAR THE GROUND OVERNIGHT AS MODELS SHOW A WELL PRONOUNCED DRY SLOT ROTATING UP FROM NEW MEXICO. FOR THE HIGH COUNTRY...ODDS LOOK BETTER FOR MEASURABLE PRECIP TODAY...BEGINNING AS EARLY AS LATE THIS MORNING. GREATER MOISTURE... BETTER SYNOPTIC SCALE LIFT..INSTABILITY AND OROGRAPHICS SHOULD PROVE ADEQUATE FOR SHOWER AND T-STORM FORMATION. SHOWERS AND T-STORM MOTIONS WILL PRIMARILY SOUTH-TO-NORTH TODAY. SO THERE`S LITTLE CHANCE THAT THE PLAINS WILL SEE MUCH IF ANY OF THIS HIGH COUNTRY CONVECTION. GUSTY WINDS AND SHORT PERIODS OF LIGHT TO MODERATE RAINFALL POSSIBLE THIS AFTERNOON THRU EARLY EVENING FROM THE FRONT RANGE WESTWARD. I PUT THE CHANCE OF MEASURABLE PRECIP IN THE HIGH COUNTRY AT 30-50 PCT...WITH AS FEW POCKETS OF 60 PCT OVER THE HIGHER PEAKS AND RIDGES ROUGHLY NORTH OF I-70 LATE. LIKE THE PLAINS...THE CHANCE OF PRECIP IN THE HIGH COUNTRY SHOULD STEADILY DECREASE WITH CLOUD COVER OVERNIGHT WITH AN INFLUX OF DRIER AIR FROM THE SOUTH AHEAD OF THE UPPER TROUGH. TEMPERATURES TODAY WILL BE QUITE WARM AGAIN BUT NOT QUITE RECORD TERRITORY. RECORD HIGH AT DENVER IS 86. SHOULD SEE LOW 80S IN THE METRO AREA AND LOW TO MID 80S ACROSS THE PLAINS. HIGH COUNTRY WILL ALSO BE UNSEASONABLY WARM TODAY WITH HIGHS IN THE UPPER 50S AND 60S. TONIGHT...TEMPERATURE WILL REMAIN QUITE MILD WITH MID 40S/ LOWER 50S ON THE PLAINS AND MOSTLY 30S IN THE HIGH COUNTRY. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 430 AM MDT FRI MAY 6 2016 LARGE UPPER LEVEL LOW WILL BE OVER THE GREAT BASIN SATURDAY. A STRONG WAVE EMBEDDED IN THE SOUTHWEST FLOW ALOFT WILL MOVE ACROSS EASTERN COLORADO SATURDAY AND EVENTUALLY BECOME THE NEW CENTER OF THE UPPER LEVEL LOW SOMEWHERE OVER WYOMING OR NORTHEAST COLORADO. FOR SATURDAY...A SURFACE LOW WILL BE OVER NORTHEAST COLORADO WITH A BOUNDARY DRAPED ACROSS THE AREA. EASTERLY WINDS NORTH OF IT WILL PUMP MOISTURE INTO THE AREA. SURFACE BASED CAPES WILL BE UP TO 2000 J/KG. THIS COMBINED WITH GOOD SHEAR IS EXPECTED TO PRODUCE SEVERE THUNDERSTORMS WITH LARGE HAIL...STRONG WINDS AND POSSIBLY A FEW TORNADOS. STILL SOME UNCERTAINTY WHERE THIS BOUNDARY WILL SET UP. LATEST MODEL RUNS ARE LITTLE MORE NORTH AND HAS MOST OF THE CONVECTION NORTH OF A LINE FROM FORT COLLING TO AKRON. STILL WOULDN`T BE SURPRISED IF THIS BOUNDARY ENDS UP FARTHER SOUTH THAN THE MODELS ARE FORECASTING. ON SUNDAY...THE ECMWF HAS THE CENTER OF THE UPPER LEVEL LOW OVER NORTHEAST COLORADO WHILE THE GFS SHOWS IT OVER WYOMING. NO STRONG FEELING WHICH ONE IS RIGHT. IT WILL BE COOL AND IF THE LOW FORMS OVER COLORADO...EXPECT MORE PRECIPITATION ACROSS THE AREA. NORTHWEST FLOW WILL PREVAIL MONDAY AS THE UPPER LEVEL LOW WEAKENS EAST OF COLORADO. STILL SHOULD BE ENOUGH MOISTURE AND INSTABILITY TO TRIGGER SCATTERED/ISOLATED SHOWERS AND STORMS. ANOTHER UPPER LEVEL LOW WILL MOVE INTO THE NORTHERN ROCKIES MONDAY. THIS LOW IS EXPECTED TO DIG SOUTH INTO WYOMING TUESDAY. ISOLATED TO SCATTERED CONVECTION WILL AGAIN BE POSSIBLE. THIS LOW IS EXPECTED TO MOVE EAST OF THE AREA WEDNESDAY AND THURSDAY. COULD SEE A FEW SHOWERS AND STORMS WEDNESDAY...BUT DRIER AND WARMER CONDITIONS SHOULD PREVAIL THURSDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1053 AM MDT FRI MAY 6 2016 THROUGH THIS AFTERNOON AND TONIGHT...VFR CONDITIONS SHOULD CONTINUE AT DENVER AREA AIRPORTS. THE DEVELOPMENT OF SOME AFTERNOON SHOWERS WITH MICROBURST POTENTIAL STILL EXISTS THIS AFTERNOON. GUSTS UP TO 40-45 MPH MAY ACCOMPANY THE HIGH BASED SHOWERS. STORM MOTIONS WILL BE FROM SOUTH TO NORTH...GIVEN THE INCREASING SOUTHERLY FLOW ALOFT IN PLACE OVER EASTERN COLORADO TODAY. MOST SHOWER ACTIVITY SHOULD BE OVER BY 7 PM TO 8 PM. SOUTHERLY WINDS ARE EXPECTED TO CONTINUE OVERNIGHT...ALTHOUGH THEY COULD BE A BIT GUSTY AT TIMES. MORE THUNDERSTORMS ARE EXPECTED SATURDAY AFTERNOON WHICH MAY BRING SOME HEAVY RAINS AND CEILINGS DOWN TO MVFR AT TIMES. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DANKERS SHORT TERM...BAKER LONG TERM...MEIER AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS ALBANY NY
408 PM EDT FRI MAY 6 2016 .SYNOPSIS... SLOW MOVING LOW PRESSURE SYSTEM ALONG THE MIDDLE ATLANTIC COASTLINE WILL CONTINUE TO IMPACT OUR REGION WITH CLOUDS AND PERIODS OF WET WEATHER. THIS STORM BEGINS TO LIFT AWAY DURING SATURDAY...HOWEVER...A STRONG COLD FRONT WILL CROSS THE REGION SATURDAY NIGHT. THIS WILL PROVIDE ADDITIONAL SHOWERS THAT WILL END FROM WEST TO EAST EARLY SUNDAY MORNING. BRISK CONDITIONS ARE EXPECTED FOR MOTHERS DAY WITH THE CHANCE FOR MORE SHOWERS DURING THE AFTERNOON HOURS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 PM EDT...H2O VAPOR LOOP REVEALS OUR PERSISTENT QUASI- STATIONARY UPPER LEVEL LOW NEAR DELMARVA WITH DEFORMATION AXIS ALONG I81 CORRIDOR. AN ADDITIONAL WAVE SEEN JUST OFFSHORE WAS ADVANCING NORTH-NORTHWEST. PER THE HRRR...SEEMS THIS WAVE WILL ENHANCE THE LIFT FOR MORE SHOWER DEVELOPMENT THROUGH THE EVENING HOURS. THIS SHOULD ROTATE FURTHER WEST WITH SOMEWHAT IMPROVING CONDITIONS TOWARD MIDNIGHT. YET CLOUDS AND SOME PATCHY FOG SHOULD PERSIST AS OVERNIGHT LOWS SHOULD DROP ABOUT 10 DEGREES FROM THIS AFTERNOONS HIGHS AS LOWER LEVEL THERMAL PROFILES DO NOT CHANGE TOO MUCH. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... SATURDAY...LATEST MODEL TRENDS SUGGEST THE OMEGA PATTERN BEGINS TO BREAK DOWN AS OUR UPPER LOW BEGINS TO DIMINISH AND LIFT EASTWARD. SO IT APPEARS THE BEST CHANCE FOR SHOWERS WILL BE ACROSS THE SOUTHEAST 2/3RDS OF THE REGION IN CLOSER PROXIMITY OF THE DEPARTING UPPER LOW. UPSTREAM...H2O VAPOR LOOP DEPICTS A RATHER SHARP SHORT WAVE TROUGH AXIS TRACKING EAST-SOUTHEAST INTO THE NORTHERN TIER OF THE CONUS. SO THERE COULD BE A BRIEF WINDOW OF MINIMAL SHOWER COVERAGE THROUGH THE AFTERNOON BEFORE THIS AFOREMENTIONED UPSTREAM SYSTEM APPROACHES. SO CONSIDERABLE CLOUD COVERAGE /SOME BREAKS OF SUNSHINE/...AND SLIGHTLY MODERATING TEMPERATURES WITH VALLEY TEMPERATURES INTO THE 60S WITH 50S ELSEWHERE. THIS UPSTREAM SYSTEM PROGRESSIVELY MOVES ACROSS SATURDAY NIGHT WITH A PERIOD OF SHOWERS. THE BEST QG FORCING RIDES MAINLY ALONG AND NORTH OF I90 WHERE WE WILL PLACE THE HIGHEST POPS. AS FOR CONVECTIVE POTENTIAL...MID LEVEL LAPSE RATES LOOK LESS THAN IDEAL WITH SHOWALTER VALUES REMAINING RATHER POSITIVE. SO WE WILL WITHHOLD THE MENTION OF THUNDER AT THIS TIME. OVERNIGHT LOWS MAINLY INTO THE 40S. FOR MOTHERS DAY, DEPARTING SHOWERS EAST OF I87 THEN AN ISALLOBARICRISE COUPLET MOVES ACROSS FOR RATHER BRISK CONDITIONS TO EVOLVE. PER BUFKIT PROFILES MOMENTUM TRANSFER...WE TAP INTO THE 30KT RANGE AS THESE VALUES SHOULD REMAIN BELOW HEADLINE CRITERIA. H850 TEMPS DROP BACK TO BELOW ZERO ACROSS THE DACKS WITH LOWER SINGLE DIGITS ELSEWHERE. SO HIGH TEMPERATURES COULD BE ACHIEVED AROUND THE NOON HOUR WITH STEADY TO SLOWING FALLING TEMPERATURES IN THE AFTERNOON. IMPROVING CONDITIONS SUNDAY NIGHT AS IT COULD BECOME QUITE CHILLY WITH PARTIAL CLEARING FOR MOST OF THE REGION. LAKE EFFECT ACTIVITY OFF ONTARIO MAY KEEP IN THE CLOUDS A BIT LONGER AND SOME SHOWERS YET THE SUBSIDENCE INVERSION LOOKS TO BE BELOW 5K FEET SO WE WILL KEEP IT DRY FOR NOW. && .LONG TERM /MONDAY THROUGH FRIDAY/... LATEST 06/12Z MODEL AND PROBABILISTIC GUIDANCE SHOWS MERIDIONAL UPPER LEVEL FLOW OVER THE NORTHERN 2/3 CONUS. FOR OUR REGION...SURFACE HIGH PRESSURE WILL BE OVER OUR REGION FOR THE FIRST HALF OF THE EXTENDED PERIOD AS OUR REGION WILL BE IN A LARGE FAVORABLE REGION OF SOME UPPER LEVEL CONVERGENCE. TEMPERATURES WILL BE AVERAGE TO SLIGHTLY ABOVE AVERAGE FOR EARLY INTO MID MAY. OVERALL...THE EXTENDED FORECAST PERIOD WILL REMAIN RATHER TRANQUIL. A DEVELOPING SURFACE LOW PRESSURE SYSTEM ACROSS THE CENTRAL PLAINS DURING THE DAY ON TUESDAY WILL HAVE A TRAILING W-E STATIONARY FRONT FROM THE OHIO VALLEY INTO THE MID ATLANTIC STATES. THIS WILL BE THE FOCUS FOR LOW PRESSURE PERTURBATIONS ALONG THE ESTABLISHED BAROCLINIC ZONE. SOME OF THE LATEST 12Z GUIDANCE SHOWS SOME MOISTURE WORKING ITS WAY NORTHWARD INTO PARTS THE REGION AT TIMES ASSOCIATED WITH THESE LOW PRESSURE PERTURBATIONS WHICH WILL BRING SLIGHT CHANCE TO CHANCE POPS...ESPECIALLY ACROSS OUR SOUTHERN REGION. AS WE GO INTO THE DAY ON THURSDAY...A DIGGING TROUGH ACROSS THE UPPER MIDWEST WILL DEVELOP WHICH WILL FURTHER ENHANCE AN UPPER LEVEL RIDGE ON THE EASTERN SEABOARD BY THURSDAY AFTERNOON. UNDER THE UPPER LEVEL RIDGE...TRANQUIL WEATHER WILL BE ESTABLISHED OVER THE ENTIRE REGION AS WE GO TOWARDS THE END OF THE EXTENDED PERIOD. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... FLYING CONDITIONS ARE CURRENTLY VFR AT KALB/KPSF/KGFL AND MVFR AT KPOU. THE STEADIEST AND HEAVIEST RAINFALL IS NOW WEST OF THE TAF SITES...BUT RADAR TRENDS AND THE 3KM HRRR SUGGEST SOME ADDITIONAL RAIN SHOWERS WILL MOVE ACROSS THE REGION LATER THIS AFTERNOON INTO THIS EVENING. THESE ADDITIONAL RAIN SHOWERS MAY LOWER VSBYS/CIGS DOWN TO MVFR AT TIMES. LIGHT N-NE WINDS WILL GENERALLY BE 5 KTS OR LESS. DURING THE OVERNIGHT HOURS...SOME ADDITIONAL RAIN SHOWERS WILL BE POSSIBLE. CIGS WILL GENERALLY REMAIN MVFR AT KGFL/KALB...SOME CIGS MAY EVEN LOWER DOWN TO IFR AT KPOU/KPSF DUE TO THE EARLIER RAINFALL TODAY KEEPING LOW LEVELS RATHER MOIST. WINDS WILL BE LIGHT AND VARIABLE OVERNIGHT. SOME IMPROVEMENT IN CIGS IS POSSIBLE BY THE MID TO LATE MORNING HOURS ON SATURDAY...OTHERWISE MVFR CONDITIONS LOOK TO CONTINUE FOR ALL SITES. WINDS WILL CONTINUE TO BE FAIRLY LIGHT AND VARIABLE. OUTLOOK... SAT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. SAT NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA. SUN: MODERATE OPERATIONAL IMPACT. WINDY. CHANCE OF SHRA. SUN NIGHT-MON NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. TUE: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. && .FIRE WEATHER... RECENT SOGGY CONDITIONS AND CLOUD COVERAGE HAS KEPT THE RELATIVE HUMIDITY VALUES ELEVATED TO REDUCE FIRE WEATHER CONCERNS. ADDITIONAL SHOWERS THROUGH THE WEEKEND AND ELEVATED MOISTURE LEVELS SHOULD KEEP THE REGION RATHER MOIST. WINDS INCREASE ON SUNDAY WITH WEST-NORTHWEST WINDS INCREASING TO BETWEEN 25 AND 35 MPH POSSIBLE. && .HYDROLOGY... MINIMAL HYDROLOGY RELATED ISSUES THROUGH THE WEEKEND INTO EARLY NEXT WEEK AS LATEST REGIONAL BASIN RAINFALL AMOUNTS ARE EXPECTED TO AVERAGE ONE HALF OF AN INCH. THE HIGHER TERRAIN MAY EXPERIENCE SLIGHTLY HIGHER VALUES BUT EXPECTATIONS ARE FOR WITHIN BANK RIVER RISES. THE ONLY SLIGHT CONCERN HAS BEEN TIDAL CONDITIONS ALONG THE HUDSON AS THE PERSISTENT UPPER LOW OVER DELMARVA ALONG WITH SOUTHEAST LOW LEVEL WINDS MAY BRING WATER LEVELS TOWARD ACTION STAGE THROUGH THE FIRST HALF OF THE WEEKEND. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...BGM NEAR TERM...BGM SHORT TERM...BGM LONG TERM...LFM AVIATION...FRUGIS FIRE WEATHER...BGM/JPV HYDROLOGY...FRUGIS/BGM/JPV WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS ALBANY NY
126 PM EDT FRI MAY 6 2016 .SYNOPSIS... A SLOW MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO RESULT IN PLENTY OF CLOUDS AND COOL TEMPERATURES TODAY. SOME RAIN IS ALSO EXPECTED TODAY INTO THIS EVENING. TEMPERATURES WILL MODERATE SATURDAY AS THE UPPER LEVEL LOW FINALLY MOVES AWAY FROM THE REGION. A COLD FRONT WILL THEN CROSS THE AREA LATE SATURDAY NIGHT INTO SUNDAY...BRINGING ANOTHER ROUND OF SHOWERS. IN ITS WAKE...DRY AND BREEZY CONDITIONS WILL BE IN STORE FOR MUCH OF MOTHERS DAY WITH COOL TEMPERATURES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF NOON EDT...NOT MUCH CHANGE TO THE OVERALL FORECAST AS UPPER LOW REMAINS QUASI-STATIONARY ALONG THE MID-ATLANTIC COASTLINE. WAVES OF RAIN SHOWERS CONTINUE TO PIVOT NORTH THEN NORTHWEST ACROSS THE SOUTHERN HALF OF THE REGION AS H2O VAPOR LOOP REVEALS A DRY SLOT APPROACHING NYC/LI AND THE MID HUDSON VALLEY. HOWEVER... ANOTHER AREA OF MOIST ADVECTION WAS SEEN OFF THE MID ATLANTIC COAST ADVANCING NORTH-NORTHWEST AS PER THE HRRR/RAP13...THIS MAY REINVIGORATE ADDITIONAL SHOWER DEVELOPMENT THROUGH THE AFTERNOON AND EVENING HOURS. SO MADE ADJUSTMENTS TO THE POP/WX FIELDS...SKY COVERAGE PER 1KM VIS IMAGERY AND TWEAK HOURLY TEMPS PER OBS. TEMPERATURES ARE EXPECTED TO WARM INTO THE 60S ACROSS THE NORTHERN HALF OF THE AREA WHERE ONSET OF RAIN IS DELAYED UNTIL THIS AFTERNOON...AND ESPECIALLY FOR AREAS WHERE CLEARING HAS OCCURRED EARLY THIS MORNING. COOLER 50S WILL CONTINUE ACROSS SOUTHERN AREAS WHERE CLOUDS/RAIN WILL MOVE IN QUICKER. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... RAIN WILL BECOME MORE INTERMITTENT AND SHOWERY THIS EVENING AS THE CUT-OFF LOW HALTS ITS NORTHWARD PROGRESS NEAR THE MASON-DIXON LINE AS IT BEGINS TO FILL/WEAKEN. PLENTY OF CLOUDS WILL LINGER THROUGH TONIGHT WITH PLENTY OF RESIDUAL LOW LEVEL MOISTURE. WILL GRADUALLY DECREASE POPS OVERNIGHT...BUT STILL MENTION SLIGHT/LOW CHANCE INTO SATURDAY MORNING. SATURDAY COULD END UP BEING THE NICEST DAY WE HAVE SEEN SINCE APRIL ACROSS THE AREA...BUT WE WILL LIKELY HAVE TO WAIT UNTIL AFTERNOON FOR MANY LOCATIONS TO SEE PARTIAL SUNSHINE. THE CUT-OFF LOW IS EXPECTED TO FINALLY DEPART AS IT TRACKS SOUTHEASTWARD OFF THE MID ATLANTIC COAST DUE TO A DIGGING UPSTREAM TROUGH ACROSS THE UPPER GREAT LAKES. SOME BRIEF RIDGING SHOULD DEVELOP DURING THE AFTERNOON WHICH SHOULD ALLOW FOR AT LEAST SOME BREAKS OF SUNSHINE. WILL STILL HAVE TO CARRY LOW CHANCE POPS THROUGH MUCH OF THE DAY FOR A PASSING SHOWER OR TWO...AS WE WILL STILL BE IN A CYCLONIC FLOW THROUGH AROUND MID AFTERNOON. TEMPS SHOULD REACH THE LOWER TO MID 60S BY LATE AFTERNOON FOR MUCH OF THE AREA. SATURDAY NIGHT THE AFOREMENTIONED UPPER LEVEL TROUGH AND ITS ASSOCIATED COLD FRONT WILL CONTINUE TO DIVE SOUTHEASTWARD ACROSS THE GREAT LAKES AND EVENTUALLY INTO OUR REGION. GOOD LOW LEVEL CONVERGENCE AND UPWARD VERTICAL MOTION ALONG THE COLD FRONT AND AHEAD OF THE LEADING SHORT WAVE WILL RESULT IN A PERIOD OF SHOWERS. THERE IS ENOUGH CONFIDENCE TO MENTION LIKELY TO CATEGORICAL POPS FROM LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING. AFTER A FEW LINGERING SHOWERS ACROSS EASTERN AREAS SUNDAY MORNING...IT WILL TURN BREEZY...COOLER AND DRIER FOR SUNDAY AFTERNOON BEHIND THE COLD FRONT. THE MAIN STORY WILL BE GUSTY W-NW WINDS ESPECIALLY DURING THE AFTERNOON INTO THE EARLY EVENING HOURS. GOOD MIXING DEVELOPING DUE TO COLD ADVECTION WILL LIKELY RESULT IN WINDS GUSTING TO BETWEEN 25 AND 35 MPH ACROSS THE REGION...WITH SOME ISOLATED 40 MPH GUSTS. WINDS WILL GRADUALLY DECREASE SUNDAY NIGHT WITH DRY CONDITIONS PERSISTING. IT WILL BE NOTICEABLY COOLER THAN RECENT NIGHTS...WITH MID 30S TO LOWER 40S FORECAST AT THIS TIME. && .LONG TERM /MONDAY THROUGH THURSDAY/... OVERALL ACTIVE WEATHER WILL CONTINUE WITH BELOW NORMAL DAYTIME HIGHS AND ABOVE NORMAL NIGHTTIME LOWS. MODEL GUIDANCE IS IN AGREEMENT THAT RIDGING WILL BUILD IN MONDAY AND MONDAY NIGHT RESULTING IN FAIR WEATHER ACROSS THE AREA. HOWEVER THIS WILL BE SHORT LIVED. A PIECE OF SOUTHERN STREAM ENERGY WILL QUICKLY APPROACH FROM THE PLAINS TUESDAY. THIS ENERGY WILL GET ABSORBED INTO THE DEVELOPING LONGWAVE TROUGH AS PIECES OF NORTHERN STREAM ENERGY ROTATE ABOUT AN UPPER LEVEL LOW AS IT MOVES OVER EASTERN QUEBEC AND NEWFOUNDLAND/LABRADOR THIS WEEK. AT THE SURFACE...A WARM FRONT EXTENDING WELL EASTWARD FROM LOW PRESSURE OVER THE PLAINS WILL APPROACH ON TUESDAY. WILL HAVE INCREASING CHANCES FOR WET WEATHER/RAIN ESPECIALLY THROUGH THE AFTERNOON HOURS INTO THE EVENING. THE BOUNDARY IS NOT EXPECTED TO LIFT NORTHWARD INTO THE AREA AS THE UPPER FLOW SHOULD KEEP THE BOUNDARY SUPPRESSED TO OUR SOUTH. A WAVE OF LOW PRESSURE IS FORECAST TO MOVES EASTWARD ALONG THE FRONT AND PASS TO OUR SOUTH SOMETIME WEDNESDAY. THERE ARE TIMING DIFFERENCES IN THE GUIDANCE WHEN EXACTLY THIS HAPPENING...HOWEVER THE PATTERN IS WET WITH OUR AREA TO THE NORTH OF THE BOUNDARY AND LOW. AS WE HEAD INTO THE LATTER PART OF THE WEEK...RIDGING IS ANTICIPATED TO BUILD IN AND MOVE ACROSS THE REGION THURSDAY WITH ANOTHER LOW PRESSURE SYSTEM ON THE APPROACH. && .AVIATION /18Z FRIDAY THROUGH TUESDAY/... FLYING CONDITIONS ARE CURRENTLY VFR AT KALB/KPSF/KGFL AND MVFR AT KPOU. THE STEADIEST AND HEAVIEST RAINFALL IS NOW WEST OF THE TAF SITES...BUT RADAR TRENDS AND THE 3KM HRRR SUGGEST SOME ADDITIONAL RAIN SHOWERS WILL MOVE ACROSS THE REGION LATER THIS AFTERNOON INTO THIS EVENING. THESE ADDITIONAL RAIN SHOWERS MAY LOWER VSBYS/CIGS DOWN TO MVFR AT TIMES. LIGHT N-NE WINDS WILL GENERALLY BE 5 KTS OR LESS. DURING THE OVERNIGHT HOURS...SOME ADDITIONAL RAIN SHOWERS WILL BE POSSIBLE. CIGS WILL GENERALLY REMAIN MVFR AT KGFL/KALB...SOME CIGS MAY EVEN LOWER DOWN TO IFR AT KPOU/KPSF DUE TO THE EARLIER RAINFALL TODAY KEEPING LOW LEVELS RATHER MOIST. WINDS WILL BE LIGHT AND VARIABLE OVERNIGHT. SOME IMPROVEMENT IN CIGS IS POSSIBLE BY THE MID TO LATE MORNING HOURS ON SATURDAY...OTHERWISE MVFR CONDITIONS LOOK TO CONTINUE FOR ALL SITES. WINDS WILL CONTINUE TO BE FAIRLY LIGHT AND VARIABLE. OUTLOOK... SAT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. SAT NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA. SUN: MODERATE OPERATIONAL IMPACT. WINDY. CHANCE OF SHRA. SUN NIGHT-MON NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. TUE: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. && .FIRE WEATHER... A SLOW MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO RESULT IN PLENTY OF CLOUDS AND COOL TEMPERATURES TODAY. SOME RAIN IS ALSO EXPECTED TODAY INTO THIS EVENING. TEMPERATURES WILL MODERATE SATURDAY AS THE UPPER LEVEL LOW FINALLY MOVES AWAY FROM THE REGION. A COLD FRONT WILL THEN CROSS THE AREA LATE SATURDAY NIGHT INTO SUNDAY...BRINGING ANOTHER ROUND OF SHOWERS. IN ITS WAKE...DRY AND BREEZY CONDITIONS WILL BE IN STORE FOR MUCH OF MOTHERS DAY WITH COOL TEMPERATURES. MINIMUM RELATIVE HUMIDITY VALUES THIS AFTERNOON WILL DROP TO AROUND 40 TO 50 PERCENT ACROSS NORTHERN AREAS AND 55 TO 75 PERCENT ACROSS SOUTHERN AREAS. RH VALUES WILL INCREASE TO BETWEEN 90 AND 100 PERCENT TONIGHT...DROPPING TO AROUND 50 TO 70 PERCENT SATURDAY AFTERNOON. WINDS TODAY WILL BE NORTHEAST AROUND 5 TO 15 MPH...BECOMING EAST AT 5 TO 10 MPH TONIGHT. WINDS WILL SHIFT TO THE SOUTHEAST ON SATURDAY AT 5 TO 10 MPH. && .HYDROLOGY... UNSETTLED WEATHER WILL CONTINUE FOR THE NEXT FEW DAYS AS AN UPPER LEVEL LOW MEANDERS CLOSE TO THE REGION. SOME RAIN WILL OCCUR ACROSS MUCH OF THE REGION TODAY INTO THIS EVENING. A FEW ADDITIONAL RAIN SHOWERS ARE POSSIBLE ON SATURDAY WITH THE UPPER LOW NEARBY. MORE SHOWERS EXPECTED SATURDAY NIGHT INTO SUNDAY MORNING WITH THE PASSAGE OF A COLD FRONT. DRY WEATHER SHOULD RETURN FOR MUCH OF SUNDAY INTO MONDAY. TOTAL QPF THROUGH THE WEEKEND LOOKS TO BE AROUND A HALF TO TWO THIRDS OF AN INCH...WITH SOME HIGH TERRAIN /ESPECIALLY IN THE CATSKILLS/ SEEING CLOSE TO AN INCH. WITH VEGETATION CONTINUING TO GREEN UP...THIS RAINFALL WILL NOT CAUSE ANY HYDROLOGY ISSUES FOR RIVERS AND STREAMS. ONLY VERY MODEST RISES ARE EXPECTED ON AREA RIVERS AND STREAMS THROUGH EARLY NEXT WEEK. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...JPV NEAR TERM...FRUGIS/BGM/JPV SHORT TERM...JPV LONG TERM...IAA AVIATION...FRUGIS FIRE WEATHER...JPV HYDROLOGY...FRUGIS/JPV
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
158 PM EDT FRI MAY 6 2016 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE INTO OUR AREA FROM THE SOUTHEAST LATER TODAY, THEN LINGER THROUGH SATURDAY BEFORE DISSIPATING. A COLD FRONT WILL MOVE THROUGH SUNDAY MORNING, FOLLOWING BY HIGH PRESSURE SUNDAY NIGHT INTO MONDAY BEFORE MOVING OFFSHORE. A WARM FRONT LIFTS NORTH ACROSS OUR AREA DURING TUESDAY, THEN STALLS IN OUR AREA WEDNESDAY INTO THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SOME HEAVIER SHOWERS HAVE BEEN TRAVERSING THE REGION THIS MORNING WITH SCATTERED SHOWERS CONTINUING ACROSS THE AREA. EXPECT THE HEAVIER RAIN TO CONTINUE TO PUSH TO THE WEST-SOUTHWEST AND OUT OF THE AREA THIS MORNING. LIGHT TO MODERATE RAIN SHOWERS WILL CONTINUE THROUGH THE REST OF THE DAY WITH SOME TAPERING OFF EXPECTED FROM EAST TO WEST LATER IN THE DAY. SPC HAS EXPANDED THE AREA OF GENERAL THUNDER SO HAVE INCLUDED A SLIGHT RISK THROUGH THIS AFTERNOON ACROSS THE ENTIRE AREA. CONSIDERABLE INSTABILITY ALOFT SUGGEST POTENTIAL FOR ISOLATED THUNDER/ASSOCIATED SMALL HAIL WITH VERY STEEP MID LVL LAPSE RATES AND LOW WBZ NEAR 6000 FT. NOT SURE WHAT WILL TRIGGER THE THUNDER EXCEPT SFC CONVERGENCE WITH THE LOW COMING ASHORE AND PERHAPS SOME AFTERNOON SFC HEATING NEAR THE APPROACHING LOW OVER DE. TEMPS MAY BE SEVERAL DEGREES COLDER THAN YDY I95 NWWD. A GUSTY NE WIND FOR A TIME THIS MORNING NEAR 20 MPH EXCEPT GUSTS MIDDAY AND EARLY AFTERNOON MONMOUTH AND OCEAN COUNTIES MAY APPROACH 35 MPH (SEE HRRR GUSTS AS A BAND OF STRONGER WIND WELL NORTH OF THE LOW CENTER SHIFTS WESTWARD WITH LOW ALONG THE S SHORE OF LI). && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... HAVE UNCERTAINTY REGARDING TIMING OF ANY SHOWERS AND ANY LEFTOVER ISOLATED EVENING TSTMS (SE PA/S NJ). CONFIDENCE ON WHAT OCCURS AND WHERE, IS BELOW AVERAGE. IN PART THIS IS DUE TO RECENT LOSS OF CONFIDENCE IN GFS QPF FCSTS. NE WIND DIMINISHING THIS EVENING AND BECOMING LIGHT SOUTHERLY ON THE DELMARVA, POSSIBLY EVEN TO I95. FOG MAY BECOME A PROBLEM TONIGHT WITH A LIGHT WIND IN THE MIDST OF VERTICALLY STACKED MOIST LOW PRESSURE SYSTEM. FCST WAS A 50 50 BLEND OF THE 00Z/6 GFS/NAM MOS. && .LONG TERM /SATURDAY THROUGH THURSDAY/... THE SYNOPTIC SETUP IS COMPRISED OF AN INITIAL CLOSED LOW CENTERED OVER OUR AREA SATURDAY, HOWEVER THIS FEATURE OPENS UP DURING SATURDAY AS IT SHIFTS EASTWARD. THIS OCCURS AS A STRONG SHORT WAVE TROUGH DIVES SOUTHEASTWARD ACROSS THE GREAT LAKES SATURDAY AND INTO THE NORTHEAST SATURDAY NIGHT AND SUNDAY. THE NEW TROUGH AMPLIFIES ACROSS THE NORTHEAST SUNDAY BEFORE GRADUALLY LIFTING OUT MONDAY. A WEAK RIDGE THEN ARRIVES FOR EARLY NEXT WEEK WITH A SURFACE WARM FRONT ALSO MOVING THROUGH. THE WARM FRONT HOWEVER MAY END UP STALLING IN OUR VICINITY WEDNESDAY AND THURSDAY AS ENERGY SHEARS EASTWARD ALONG IT. GIVEN THE PATTERN CHANGE, MUCH WARMER AIR IS EXPECTED TO ARRIVE NEXT WEEK WITH THIS CHANGE STARTING OVER THE WEEKEND ESPECIALLY DURING SUNDAY. THE EXTENT OF THE WARMING THOUGH NEXT WEEK WILL DEPEND ON THE PLACEMENT OF THE FRONTAL BOUNDARY AS IT MAY MEANDER ACROSS OUR CWA AND ALSO PRECIPITATION CHCS. WE USED A MODEL BLEND APPROACH FOR SATURDAY THROUGH SUNDAY NIGHT, THEN BLENDED IN THE 00Z WPC GUIDANCE THEREAFTER. SOME ADJUSTMENTS WERE THEN MADE FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES. FOR SATURDAY AND SUNDAY...THIS TIME FRAME BEGINS WITH A CLOSED LOW RIGHT OVER OUR AREA SATURDAY MORNING, HOWEVER THIS FEATURE WILL OPEN UP AND SHIFT EASTWARD DURING THE COURSE OF THE DAY. THIS WILL BE DUE TO A KICKER SHORT WAVE TROUGH AMPLIFYING ACROSS THE GREAT LAKES REGION. A CORE OF -20C TO -24C AIR AT 500 MB IS OVER OUR AREA SATURDAY MORNING, HOWEVER THIS MODIFIES THROUGH THE DAY AS THE TROUGH OPENS UP AND SHIFTS TO OUR EAST. THE PRESENCE OF COLD AIR ALOFT COMBINED WITH SOME LIFT FROM THE CLOSED LOW SHOULD RESULT IN MAINLY SCATTERED SHOWERS SATURDAY ESPECIALLY INLAND. THE FLOW IS LIGHT UNDER THE CLOSED LOW THEREFORE SHOWERS SHOULD BE SLOW MOVERS. SINCE THE AIRMASS IS WARMING DURING THE COURSE OF THE DAY, THIS MAY MITIGATE THE INSTABILITY POTENTIAL. IT APPEARS ANY INSTABILITY IS MARGINAL AND THEREFORE THUNDER WAS NOT ADDED FOR SATURDAY ATTM. AS WE LOSE THE CONTINUOUS ONSHORE FLOW COMPONENT AND THE TROUGH ALOFT WEAKENING THROUGH SATURDAY, THERE SHOULD BE AT LEAST SOME BREAKS OF SUNSHINE. AN AMPLIFYING TROUGH FROM THE GREAT LAKES THEN STARTS TO NEAR OUR AREA TOWARD DAYBREAK SUNDAY. LOW PRESSURE TRACKING TO OUR NORTH WILL PULL A COLD FRONT INTO OUR AREA LATE SATURDAY NIGHT AND THIS FRONT MAY MOVE IN A BIT FASTER. THERE APPEARS TO BE A PLUME OF DEEPER MOISTURE IN COMBINATION WITH FORCING FOR ASCENT TO DRIVE SOME SHOWERS /PERHAPS A BAND OF SHOWERS/ ACROSS MUCH OF OUR AREA. THE STRONGEST FORCING MAY GLANCE OUR NORTHERN AREAS AND THEREFORE THE HIGHEST POPS WERE PLACED THERE LATER AT NIGHT. ANY SHOWERS SHOULD QUICKLY SHIFT OFFSHORE SUNDAY MORNING AS THE COLD FRONT ALSO EXITS, THEN DRIER AIR AND BETTER MIXING WILL PROMOTE SUNSHINE FINALLY RETURNING FOR THE AFTERNOON. IT WILL BE A BIT BREEZY THOUGH SUNDAY IN THE WAKE OF THE COLD FRONT AS LOW-LEVEL LAPSE RATES STEEPEN AND THE PRESSURE GRADIENT TIGHTENS. WE WENT A BIT WARMER THAN MOS FOR SUNDAY ESPECIALLY FOR THE COASTAL PLAIN GIVEN DOWNSLOPING FLOW. HIGH PRESSURE THEN STARTS TO ARRIVE SUNDAY NIGHT ALLOWING THE WINDS TO DIMINISH. FOR MONDAY AND TUESDAY...SOME WEAK RIDGING ARRIVES DURING MONDAY, ALLOWING SURFACE HIGH PRESSURE TO BE OVER OUR CWA TO START BUT IT LOOKS TO SHIFT OFFSHORE LATER MONDAY. THIS WILL ALLOW A SOUTHERLY FLOW TO BECOME BETTER ESTABLISHED AND WITH DOWNSTREAM WAA INCREASING, A WARMER TIME FRAME IS EXPECTED. THE WAA WILL BE USHERED IN VIA A WARM FRONT AS IT CROSSES THE AREA DURING TUESDAY, AND THERE COULD BE ENOUGH LIFT TO PRODUCE SOME SHOWERS OR A THUNDERSTORM MAINLY TUESDAY AFTERNOON AND NIGHT. THE FORECAST CHALLENGE IS THAT THIS FRONT MAY THEN STALL IN OUR AREA AS ENERGY INITIALLY SHEARS EASTWARD ALONG IT. THIS SHEARING ENERGY COULD PRODUCE SOME CONVECTION. FOR WEDNESDAY AND THURSDAY...THE FORECAST CHALLENGE IS WITH THE FRONTAL ZONE AS IT LOOKS TO BE DRAPED ACROSS OUR AREA, HOWEVER A TROUGH AMPLIFYING ACROSS NEW ENGLAND WEDNESDAY MAY PUSH THE FRONT FARTHER SOUTHWARD. THIS SOUTHWARD PUSH COULD BE ENHANCED AS HIGH PRESSURE MAY BUILD DOWN SOME FROM NORTHERN NEW ENGLAND. A TROUGH IN THE MIDWEST HOWEVER PUSHES SURFACE LOW PRESSURE UP THE OHIO VALLEY WEDNESDAY NIGHT INTO THURSDAY, WITH DOWNSTREAM WAA AND SOUTHERLY FLOW ALLOWING THE BOUNDARY TO START LIFTING NORTHWARD SOME AS A WARM FRONT. THIS TIME FRAME SHOULD BE ON THE WARMER SIDE, HOWEVER THIS WILL ULTIMATELY DEPEND ON THE POSITIONING OF THE FRONTAL BOUNDARY AND ANY CONVECTION THAT OCCURS. GIVEN THE UNCERTAINTY, WE BLENDED THE 00Z WPC GUIDANCE IN WITH CONTINUITY AND THEN MADE SOME TWEAKS. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. SHOWERS HAVE LARGELY CLEARED THE TERMINALS WITH ONLY SOME SHOWERS, POSSIBLY AN ISOLATED THUNDERSTORM, AFFECTING KRDG THROUGH 19Z. LOW PRESSURE CONTINUES TO PUSH WESTWARD FROM THE ATLANTIC AND INTO OUR AREA. AS THIS OCCURS, THE ATMOSPHERE WILL DRY ALOFT WHILE THE LOW LEVELS CONTINUE TO HAVE CONSIDERABLE MOISTURE. THIS WOULD LEAD TO MORE OF A DRIZZLE EVENT AND WE TRANSITION THE TERMINALS TO DRIZZLE FROM 22Z-00Z AND THROUGH MUCH OF THE NIGHT. WITH THE LOW LEVEL MOISTURE IN PLACE, LOW CLOUDS WILL CERTAINLY BE THE BIGGEST ISSUE AFFECTING THE TERMINALS THROUGH THE PERIOD. BASES WILL GRADUALLY FALL THIS AFTERNOON AND EVENING TO BELOW 1000FT, DROPPING AS LOW AS 400 FT AT SOME LOCATIONS. LIFR/IFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE OVERNIGHT HOURS INTO SATURDAY MORNING. SATURDAY...IMPROVMENT WILL BE SLOW TO OCCUR ON SATURDAY AS THE LOW LEVEL MOISTURE HANGS ON IN THE EASTERLY FLOW. WINDS WILL START TO SHIFT TO THE WEST-SOUTHWEST AND WE EXPECT CEILINGS AND VISIBILITIES TO RISE BY MID TO LATE MORNING, WITH THE POTENTIAL TO GO VFR BY MID TO LATE AFTERNOON ACROSS THE TERMINALS. OUTLOOK... SATURDAY NIGHT...A BAND OF SHOWERS ARRIVES LATE AT NIGHT WITH A COLD FRONT, DROPPING CONDITIONS BELOW VFR. SOUTHWESTERLY WINDS MAINLY LESS THAN 10 KNOTS. SUNDAY...BRIEF MVFR CONDITIONS IN THE MORNING WITH SOME SHOWERS AS A COLD FRONT MOVES THROUGH, OTHERWISE VFR. WEST TO NORTHWEST WINDS INCREASE TO 12-18 KNOTS WITH GUSTS TO 25 KNOTS, THEN DIMINISH AT NIGHT. MONDAY AND TUESDAY...VFR, THEN POSSIBLY SOME MVFR DURING TUESDAY WITH A CHANCE OF SHOWERS AS A WARM FRONT MOVES THROUGH. WESTERLY WINDS AROUND 10 KNOTS MONDAY, BECOMING LIGHT AT NIGHT THEN SHIFTING TO SOUTHERLY TUESDAY. && .MARINE... WE HAVE UPGRADED THE SMALL CRAFT ADVISORY ON OUR NORTHERN TWO OCEAN ZONES TO A GALE WARNING THROUGH THIS AFTERNOON. GALE FORCE GUSTS ARE EXPECTED TO OCCUR OVER THE NEXT SEVERAL HOURS AND THEN SHOULD TAPER OFF AS WE HEAD INTO THE LATE AFTERNOON AND EVENING. SCA CONTINUES OCEAN WATERS THROUGH TONIGHT, ESPECIALLY DUE TO SEAS. FOG MAY BECOME A MARINE HAZARD LATER THIS FRIDAY NIGHT. OUTLOOK... SATURDAY...THE WINDS ARE ANTICIPATED TO BE LIGHT AS A CLOSED LOW INITIALLY OVERHEAD WEAKENS AND THEN SHIFTS EASTWARD. THE SEAS MAY BE RIGHT AT 5 FEET TO START ESPECIALLY ACROSS THE NORTHERN WATERS BUT OVERALL THE CONDITIONS SHOULD BE TRENDING BELOW ADVISORY CRITERIA. THEREFORE WE DID NOT EXTEND THE ADVISORY ATTM. SUNDAY...WEST TO NORTHWEST WINDS TURN GUSTY TO AROUND 20 KNOTS WITH SEAS AT OR BELOW 4 FEET. IT IS POSSIBLE WINDS GUST TO 25 KNOTS NEARSHORE, HOWEVER OVERALL CONDITIONS ARE ANTICIPATED TO BE BELOW ADVISORY CRITERIA. MONDAY AND TUESDAY...SUB-ADVISORY CONDITIONS ARE ANTICIPATED DESPITE SOME INCREASE IN A SOUTHERLY WIND MONDAY AND THEN AGAIN LATER TUESDAY. && .TIDES/COASTAL FLOODING... PLEASE SEE THE HAZARD CFW STATEMENT FOR THE PARTICULARS RELATING TO EACH AREA. PHL: TIDAL DE ADVY EXPIRED BUT MAY NEED A NEW ONE TO BE ISSUED THIS AFTERNOON FOR THE EARLY SATURDAY MORNING HIGH TIDE CYCLE. CONFIDENCE IN EXCEEDING THE ADVY THRESHOLD WAS NOT QUITE CATEGORICAL ON THIS SHIFT. REEDY POINT UPPER DE BAY, LOWER TIDAL DE LINKED: REISSUED FOR LATE THIS EVENING, SINCE CONFIDENCE IS CATEGORICAL THAT IT WILL REOCCUR, ESPECIALLY BECAUSE THE FUNNELED ENE FLOW THIS MORNING TURNS LIGHT SOUTH THIS EVENING. NJ/DE ATLC COASTS: NO CHANGE IN THE PREVIOUS WARNING. THE TIDAL SURGE IS EXPECTED TO STAY AROUND 1 TO 1.5 FEET TODAY IN THE CONTINUING NORTHEASTERLY FLOW. THE THURSDAY EVENING HIGH TIDE SAW MANY OBSERVING SITES EITHER JUST REACH OR FALL JUST SHY OF MODERATE FLOODING THRESHOLDS. WE ARE FORECASTING MINOR TIDAL FLOODING AROUND THIS MORNING`S HIGH TIDE AND MODERATE FLOODING AROUND THIS FRIDAY EVENING`S HIGH TIDE. RATHER THAN CARRY MULTIPLE HEADLINES, WE CONTINUED WITH THE COASTAL FLOOD WARNING TO COVER BOTH HIGH TIDE CYCLES. MINOR TIDAL FLOODING MAY LINGER WITH THE HIGH TIDE CYCLES ON SATURDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...COASTAL FLOOD WARNING UNTIL 1 AM EDT SATURDAY FOR NJZ012>014- 020>027. COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 2 AM EDT SATURDAY FOR NJZ016. DE...COASTAL FLOOD WARNING UNTIL 1 AM EDT SATURDAY FOR DEZ002>004. COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 2 AM EDT SATURDAY FOR DEZ001. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ452>455. GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR ANZ450-451. && $$ SYNOPSIS...GORSE NEAR TERM...DRAG/MEOLA SHORT TERM...DRAG LONG TERM...GORSE AVIATION...GORSE/MEOLA MARINE...DRAG/GORSE/MEOLA TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
212 PM EDT FRI MAY 6 2016 .UPDATE... ISSUED AT 125 PM EDT FRI MAY 6 2016 POPS FOR THE EASTERN COUNTIES OVER THE NEXT COUPLE OF HOURS WERE INCREASED BASED ON RADAR TRENDS. OTHERWISE...NO OTHER CHANGES WERE NEEDED AT THIS TIME. UPDATE ISSUED AT 1140 AM EDT FRI MAY 6 2016 A COUPLE OF QUICK UPDATES HAVE BEEN DONE TO FINE TUNE THE HOURLY GRIDS BASED ON OBSERVATIONS AND NEAR TERM MODEL TRENDS. POPS WERE INCREASED SLIGHTLY FOR THIS AFTERNOON EAST OF A SANDY HOOK TO JACKSON TO HARLAN LINE FOR BETTER AGREEMENT WITH SHORT TERM MODEL GUIDANCE...CU DEVELOPMENT AND TRENDS. THE BEST CHANCES FOR ANY SHOWERS WILL BE IN THE BIG SANDY REGION. UPDATE ISSUED AT 635 AM EDT FRI MAY 6 2016 JUST A QUICK UPDATE TO FINE TUNE THE GRIDS PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 405 AM EDT FRI MAY 6 2016 07Z SFC ANALYSIS SHOWS LOW PRESSURE OFF TO THE EAST OF THE APPALACHIANS. WHILE HIGH PRESSURE IS FOUND TO THE SOUTHWEST. A FEW LINGERING LIGHT SHOWERS ARE DRIFTING SOUTH THROUGH FAR EASTERN KENTUCKY FROM THAT EASTERN LOW. IN CONJUNCTION WITH THIS...LOW AND MID LEVEL CLOUDS ARE FOUND CLOSER TO THE VIRGINIA AND WEST VIRGINIA BORDER. IN THE CLEARING TO THE WEST OF THE BORDER AREAS...PATCHY FOG IS NOTED IN THE SOME OF THE OBSERVATIONS. TEMPERATURES ARE RUNNING IN THE LOW TO MID 40S ACROSS THE AREA WITH DEWPOINTS NOT FAR AWAY...WHILE WINDS ARE GENERALLY LIGHT FROM THE NORTHWEST. THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST. THEY ALL DEPICT A CONUS OMEGA BLOCK SHIFTING EAST AND OPENING UP DURING THE NEXT 48 HOURS. A DEEP CLOSED LOW DESCENDING THROUGH THE SOUTHERN APPALACHIANS THIS MORNING WILL PIVOT TO THE NORTHEAST BY EVENING BEFORE BEING PICKED UP BY THE NORTHERN STREAM FLOW AND DEPARTING OFF THE MID ATLANTIC COAST SATURDAY EVENING. IN ITS WAKE...RISING HEIGHTS AND RIDGING WILL SPREAD FROM THE SOUTHERN PLAINS AND ACROSS THE MISSISSIPPI VALLEY TOWARD KENTUCKY. HOWEVER...IN ASSOCIATION WITH A HUDSON BAY UPPER LOW DESCENDING INTO THE GREAT LAKES...A MINOR WAVE WILL SQUEEZE BY EASTERN KENTUCKY TO THE NORTH LATE SATURDAY. GIVEN THE MODEL AGREEMENT HAVE FOLLOWED A GENERAL BLEND WITH A STRONG LEAN TOWARD THE HRRR EARLY ON AND THE NAM12 THEREAFTER. SENSIBLE WEATHER WILL FEATURE A MILDER DAY THAN YESTERDAY AS SOME SUNSHINE RETURNS AND THE COLD AIR DEPARTS TO THE EAST. ISOLATED TO SCATTERED SHOWERS WILL BE FOUND OVER FAR EASTERN KENTUCKY THROUGH THE AFTERNOON. FOR TONIGHT...EXPECT A SMALL RIDGE TO VALLEY SPLIT TO SET UP AHEAD OF A DEVELOPING WARM FRONT WITH PATCHY VALLEY FOG AROUND...SIMILAR TO THIS MORNING. A FEW LIGHT SHOWERS CANNOT BE RULED OUT WITH THAT BOUNDARY THROUGH THE MORNING...ESPECIALLY EAST BY MIDDAY SATURDAY. A COLD FRONT WILL THEN SETTLE SOUTH TOWARD EASTERN KENTUCKY LATER SATURDAY. BETWEEN THESE FEATURES...OUR AREA WILL BE IN THE WARM SECTOR OF A QUICK MOVING SFC LOW AND AS A RESULT COULD SEE SOME CONVECTION DEVELOP WITH FAVORABLE PARAMETERS FOR STRONG TO SEVERE STORMS BUILDING DURING THE AFTERNOON AND INTO THE EVENING. SPECIFICALLY...CAPE WILL BE MODERATE WITH LOW LIS AND VEERING/INCREASING WINDS WITH HEIGHT. WILL HIGHLIGHT THIS FURTHER IN THE FORTHCOMING HWO WITH HAIL AND GUSTY WINDS THE MAIN THREAT. USED THE SHORTBLEND/SUPERBLEND AS A STARTING POINT FOR MOST ELEMENTS WITH SOME MINOR ADJUSTMENTS TO THE AFTERNOON DEWPOINTS AND SOME TERRAIN DIFFERENCES FOR TEMPERATURES TONIGHT. DID ADJUST POPS TO BE A BIT ABOVE THE POPULATION SCHEME...IN THE EAST THROUGH TODAY AND ALSO FOR THE STRONG/SEVERE STORM CONCERNS ON SATURDAY AFTERNOON. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 405 AM EDT FRI MAY 6 2016 THE EXTENDED PORTION OF THE FORECAST BEGINS SATURDAY NIGHT WITH AN ACTIVE PATTERN IN PLACE. UPPER CLOSED LOW OVER THE SOUTHEASTERN CANADA REGION WILL BE IN PLACE THROUGH THE WEEKEND AS IT SLOWLY SHIFTS EAST INTO THE COMING WEEK. THIS FEATURE CONTINUES TO SWING A FEW SHORTWAVES INTO THE LOWER GREAT LAKES REGION THROUGH THE START OF THE NEW WEEK. MEANWHILE...AS A WEAKENING RIDGE OVER THE SOUTHEAST CONTINUES TO WEAKEN AND SHIFT EAST AS WELL WITH ANOTHER UPPER LEVEL LOW OVER THE CENTRAL PLAINS. THIS FEATURE OPENS AND EJECTS EAST INTO THE OHIO VALLEY BY MID WEEK. FOLLOWING THIS...TOWARDS THE END OF THE EXTENDED PERIOD...THE PATTERN BECOMES MORE AMPLIFIED AS ANOTHER UPPER LOW MOVES INTO THE UPPER PLAINS WITH A WEAKENING RIDGE OVER THE OH VALLEY SHIFTING. OVERALL...BOTH THE GFS AND EURO HAVE A DECENT HANDLE ON THE UPPER LEVEL PATTERN THROUGH NEXT WEEK. THOUGH THE GFS IS A BIT MORE DRIER THAN THE EURO...THE BOTTOM LINE IS THAT THE EXTENDED SEEMS QUITE WET AND ACTIVE. THIS SOLUTION IS ALSO CONFIRMED BY THE ALL MODEL BLEND AS WELL KEEPING THE CHANCE OF PRECIP THROUGH JUST ABOUT EVERY DAY OF THE EXTENDED. NEAR THE SURFACE HEADING INTO SATURDAY NIGHT AND SUNDAY...A SURFACE LOW PRESSURE SYSTEM DEVELOPING UP OVER THE CENTRAL PLAINS SETS UP A WARM FRONT INTO THE MIDWEST AND A QUASI STATIONARY BOUNDARY INTO THE OH VALLEY. THIS BOUNDARY BECOMES A FOCUS FOR CONTINUED CONVECTION SATURDAY NIGHT AND SUNDAY. IN FACT...THE EURO MIGHT SUGGEST AN MCS SET UP FOR THIS TIME PERIOD. INSTABILITY AND SHEAR SEEM SUBSTANTIAL FOR ORGANIZED CONVECTION AT LEAST EARLY IN THE SATURDAY NIGHT PERIOD AND AGAIN SUNDAY AFTERNOON FOCUSING ON MAX HEATING. STRONG CAPPING HEADING INTO THE DAY MONDAY WOULD LIMIT CONVECTION A BIT MORE AS THE MENTIONED BOUNDARY LIFTS NORTH. STILL WILL KEEP LOW CHANCE POPS IN THE NORTH CLOSER TO THE BOUNDARY. TUESDAY...THE SYSTEM OUT WEST SHIFTS EAST WITH STRONG UPPER LEVEL SUPPORT. STRONG CONVECTION SEEMS TO DEVELOP AHEAD OF THE COLD FRONT TUESDAY AFTERNOON INTO TUESDAY NIGHT. THIS WILL KEEP LIKELY POPS IN THE FORECAST THROUGH WEDNESDAY AS GFS MODEL SOUNDINGS KEEP GOOD INSTABILITY IN PLACE TUESDAY AND WEDNESDAY AFTERNOON. IN FACT...THIS SYSTEM WILL BE FOLLOWED BY A DISTURBANCE TO MOVE INTO THE AREA ON THURSDAY. MODELS HIGHLIGHT AN ACTIVE EXTENDED FORECAST THROUGH NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 212 PM EDT FRI MAY 6 2016 CU AND ISOLATED TO SCATTERED SHOWERS HAVE DEVELOPED ACROSS THE EASTERN PARTS OF THE REGION GENERALLY SOUTH AND EAST OF JKL AND NEAR SJS UNDER THE INFLUENCE OF A DEPARTING UPPER LEVEL LOW. VCSH HAS BEEN INCLUDED FOR SJS AND JKL FOR THE NEXT FEW HOURS. BRIEF MVFR IS POSSIBLE IN LOCATIONS THAT RECEIVE A DIRECT HIT FROM A SHOWER. OTHERWISE...NORTHERLY WINDS AT NEAR 10KT WITH SOME GUSTS AS HIGH AS 20KT ARE EXPECTED THROUGH SUNSET AT THE TAF SITES WITH CU OR STRATOCU IN THE VFR RANGE. WINDS SHOULD THEN SLACKEN...ALTHOUGH THEY COULD BECOME GUSTY LATE IN THE PERIOD...AROUND 15Z...MAINLY AT SYM...LOZ...AND SME. VALLEY FOG SHOULD AGAIN FORM AND MAY LIMIT VIS TO IFR RANGE BETWEEN 4Z AND 13Z IN SOME AREAS...BUT IS NOT EXPECTED AT THE TAF SITES. A DISTURBANCE WILL BRING INCREASE MID LEVEL CLOUDS AFTER 8Z AND CIGS DOWN NEAR 5KFT WILL BE POSSIBLE ALONG WITH A STRAY SHOWER. FOR THE MOST PART THOUGH...VFR SHOULD PREVAIL THROUGH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...JP
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
302 PM CDT FRI MAY 6 2016 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 301 PM CDT FRI MAY 6 2016 TONIGHT AND SATURDAY...ISOLATED SHOWERS ARE DEVELOPING IN THE PANHANDLE...MOVING EAST...AS FORECAST BY THE HRRR MODEL. THIS ACTIVITY SHOULD MOVE EAST NORTHEAST THIS EVENING AND POSE A WIND GUST THREAT. THEY ARE IN THE WARM SECTOR. OTHER ISOLATED SHOWERS AND THUNDERSTORMS DEVELOP ALONG THE COLD FRONT DROPPING THROUGH THE SOUTH DAKOTA. THIS ACTIVITY MAY COALESCE ACROSS NRN NEB TONIGHT BUT THE NAM IS SHOWING MUCH LESS STORM COVERAGE THAN YESTERDAYS MODEL RUN. THUS...LESS STORM COVERAGE WILL HOLD UP THE PROGRESS OF THE COLD FRONT WHICH WILL BECOME STATIONARY ACROSS THE SWRN NEB AND BECOME THE FOCUS FOR SEVERE WEATHER SATURDAY AFTN. THIS IS FARTHER NORTH AND THE GFS SHOWS THE SAME PLACING MORE OF WESTERN AND NCNTL NEB IN SEVERE WEATHER POTENTIAL. CONRAD SUGGESTS DOMINANT RIGHT MOVING SUPER CELLS AT THE ONSET. SHEAR WEAKENS IN THE LATE EVENING AND A MULTICELLS REGIME TAKES HOLD. 0-1KM HELICITY INCREASE IN THE EARLY EVENING SUGGESTING AN ISOLATED TORNADO THREAT. THE LATEST MODEL BLEND PLUS BIAS CORRECTION SHOWS DEW POINTS IN THE LOWER 50S ALONG I-80 SATURDAY AFTERNOON WHILE THE MET GUIDANCE SHOWS MID 50S. NONE OF THESE NUMBERS SUGGEST A SHALLOW MIXING HEIGHT BUT GIVEN THE FRONT AND HIGH HELICITY AN ISOLATED TORNADO MAY DEVELOP. THIS WOULD BE THE FIRST OF TWO ROUNDS OF CONVECTION. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 301 PM CDT FRI MAY 6 2016 SATURDAY NIGHT THROUGH MONDAY...STORM COVERAGE BECOMES MORE NUMEROUS SATURDAY EVENING AS THE 700MB WARM FRONT LIFTS THROUGH THE FORECAST AREA. A SECOND ROUND OF CONVECTION IS INDICATED IN THE NAM MODEL LIFTING VERY QUICKLY THROUGH THE FCST AREA. THE LATEST MODEL CONSENSUS HAS A CLOSED H700MB LOW ACROSS ERN WY/NERN COLO SUNDAY MORNING AT 12Z. THIS LOW MOVES VERY SLOWLY INTO THE PANHANDLE SUNDAY. THE NAM SHOWS INSTABILITY LIFTING NORTH INTO NCNTL NEB SUNDAY AFTN. THE ATM SHOULD BECOME SUFFICIENTLY UNSTABLE ALONG AND EAST OF HIGHWAY 183 FOR STORM DEVELOPMENT. THE STORM MODE IS UNCERTAIN AT THIS TIME. THERE IS A LARGE SPREAD IN MODEL SOLNS FOR MONDAY BUT SOME SORT OF UPPER LEVEL LOW SHOULD STILL BE LOCATED SOMEWHERE ACROSS NEBRASKA OR WRN IA/MN...NWRN KS OR SRN SD. THIS SHOULD PRODUCE A LIKELY CHANCE FOR SHOWERS AND THUNDERSTORMS MONDAY...MAINLY EAST CLOSER TO THE WARM SECTOR. THERE IS NO REAL CHANGE IN THE TEMPERATURE FORECAST. THE FRONT IS FARTHER NORTH SATURDAY SUPPORTING HIGHS IN THE 70S ACROSS SWRN NEB. HIGHS IN THE 60S ARE EXPECTED SUNDAY AND MONDAY WITH LOWS IN THE 40S. MONDAY NIGHT THROUGH FRIDAY...A SECOND UPPER LEVEL LOW WILL MOVE INTO THE DAKOTAS TUESDAY AND MOVE SLOWLY INTO THE UPPER MIDWEST BY THURSDAY MORNING. UPPER LEVEL HEIGHTS AMPLIFY ACROSS WRN N AMERICA SUPPORTING A FRESH SHOT OF CANADIAN HIGH PRESSURE. RAIN CHANCES DECREASE TO ISOLATED WEDNESDAY AND BEYOND. THE MODELS CONTINUE TO SHOW COLD AIR ALOFT WITH TEMPERATURES AT H500MB AROUND -18C AND H700MB TEMPERATURES FALL TO 0C OR COLDER. THE ECM SHOWS H500MB TEMPERATURES FALLING TO -25C THURSDAY MORNING. BIAS CORRECTION ADDED TO THE MAX AND MIN TEMPERATURES PRODUCED TEMPERATURES SEVERAL DEGREES COLDER AND FROST MAY DEVELOP ACROSS THE WRN SANDHILLS AND EASTERN PANHANDLE. SKIES WOULD NEED TO CLEAR TO SUPPORT RADIATIONAL COOLING. LOWS IN THE 30S AND 40S ARE EXPECTED WEDNESDAY THROUGH FRIDAY. HIGHS RISE INTO THE 60S TO NEAR 70. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1221 PM CDT FRI MAY 6 2016 VFR IS GENERALLY EXPECTED THIS AFTERNOON THROUGH SATURDAY MORNING. ISOLATED SHOWERS AND THUNDERSTORMS CAPABLE OF GUSTY WINDS ARE INDICATED BY THE RAP AND HRRR MODELS THIS EVENING. THIS ACTIVITY IS EXPECTED TO DIMINISH BY 06Z. THE LATEST NAM MODEL RUN SHOWS MUCH LESS STORM COVERAGE. THUS ISOLATED STORM COVERAGE IS ALL THAT IS EXPECTED LATE TONIGHT AND SATURDAY MORNING. && .HYDROLOGY... ISSUED AT 301 PM CDT FRI MAY 6 2016 A FLOOD ADVISORY WITH MINOR FLOODING TO CONTINUE ALONG THE NORTH PLATTE RIVER NEAR LEWELLEN. THE CURRENT STAGE AT LEWELLEN IS 7.7 FEET WHICH IS JUST OVER THE FLOOD STAGE OF 7.5 FEET. A SLOW RISE TO 7.9 FEET IS EXPECTED OVER THE NEXT SEVERAL DAYS. ELEVATED RIVER LEVELS WILL CONTINUE UPSTREAM AT LISCO. ALONG THE SOUTH PLATTE RIVER ELEVATED FLOWS WILL ALSO CONTINUE FOR THE NEXT SEVERAL DAYS. AT THIS TIME...THE SOUTH PLATTE AND MAIN STEM PLATTE RIVER FROM ROSCOE TO BRADY IS EXPECTED TO REMAIN BELOW FLOOD STAGE. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION...CDC HYDROLOGY...ROBERG
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1224 PM CDT FRI MAY 6 2016 .SYNOPSIS... ISSUED AT 344 AM CDT FRI MAY 6 2016 A HIGHLY AMPLIFIED H5 PATTERN CONTINUES ACROSS THE CONUS TONIGHT. UA ANALYSIS FROM EARLIER THIS EVENING HAD A RIDGE OF HIGH PRESSURE EXTENDING FROM EASTERN NEW MEXICO...NORTH TO SRN SASKATCHEWAN. CLOSED LOWS WERE PRESENT ON EITHER SIDE OF THE RIDGE. THE FIRST LOW WAS LOCATED OVER THE CAROLINAS...WHILE THE SECOND WAS OFF THE COAST OF CENTRAL CALIFORNIA. AT THE SURFACE...HIGH PRESSURE WAS LOCATED OVER THE OZARKS WHILE A COLD FRONT EXTENDED FROM FAR NWRN NORTH DAKOTA INTO CENTRAL MONTANA. BETWEEN THE APPG FRONT AND NORTHWEST OF THE SURFACE HIGH...SRLY WINDS WERE PRESENT ACORSS WESTERN AND NORTH CENTRAL NEBRASKA TONIGHT. WITH SRLY WINDS OF 10 TO 20 MPH ATTM...TEMPERATURES AS OF 3 AM CDT WERE VERY MILD ACROSS THE FORECAST AREA. READINGS RANGED FROM 56 AT OGALLALA AND IMPERIAL...TO 63 AT VALENTINE...AINSWORTH AND THEDFORD. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 344 AM CDT FRI MAY 6 2016 OVER THE NEXT 24 HOURS...THE MAIN FORECAST CHALLENGS ARE TEMPERATURES TODAY...FOLLOWED BY THE THREAT FOR THUNDERSTORMS IN THE WEST AND NORTHWEST TONIGHT. FOR TODAY...THE COLD FRONT...CURRENTLY PUSHING INTO NORTHERN NORTH DAKOTA...WILL MIGRATE SOUTH INTO CENTRAL SOUTH DAKOTA BY THIS AFTERNOON...IMMEDIATELY SOUTH OF THIS FEATURE...H85 TEMPS WILL REACH 22 TO 25C ACROSS FAR NORTHWESTERN NEBRASKA AND SOUTHWESTERN SOUTH DAKOTA. TEMPS TODAY WILL BE WARMEST ACROSS THE FAR SOUTHWESTERN CWA WHERE H85 TEMPS REACH 24 TO 26C THIS AFTERNOON. ANOTHER AREA OF WARM TEMPS WILL BE ACROSS FAR NORTHWESTERN AND NORTH CENTRAL NEBRASKA INVOF THE APPG COLD FRONT. IN THESE AREAS I WENT ABOVE GUIDANCE ON TEMPS AS WE TYPICALLY ARE WARMER WITH AN APPROACHING COLD FROPA...IE COMPRESSIONAL WARMING. AS FOR THUNDERSTORM CHANCES LATER TODAY...HAVE LEFT OUT MENTION OF PCPN IN THE FCST. LOOKING AT THE NAM SOLN FOR THIS AFTERNOON...YEILDED SOME DECENT ELEVATED INSTABILITY IN THE WEST AND SOUTHWESTERN CWA. HOWEVER...THE CAP IS REALLY STRONG THIS AFTERNOON AND DOESN/T WEAKEN UNTIL LATER THIS EVENING. WITH THIS IN MIND...WILL CONTINUE A DRY FCST THROUGH 00Z SAT. FOR TONIGHT...THUNDERSTORM CHANCES WILL BEGIN TO INCREASE LATER THIS EVENING AS THE COLD FRONT BEGINS TO PUSH INTO NORTHERN NEBRASKA. THE MODELS CONTINUE TO DEVELOP SOME WEAK CONVECTION ALONG AND NORTH OF THE FRONT OVERNIGHT AND HAVE PLACED MY HIGHEST POPS ACROSS THE NORTHERN HALF OF THE CWA WHERE THE FRONT IS EXPECTED TO BE LOCATED TONIGHT. FURTHER SOUTH...ELEVATED INSTABILITY WILL CONTINUE OVERNIGHT...HOWEVER THERE IS NOT MUCH OF ANY LOW LEVEL FOCUS FOR CONVECTIVE INITIATION. WITH THIS IN MIND...HAVE LIMITED POPS TO SLIGHTS IN THE SOUTH OVERNIGHT AS THE 4KM WRF AND GFS SOLNS HAVE SOME INDICATION OF ISOLATED STORMS LATE TONIGHT IN THE EASTERN PANHANDLE AND SWRN NEBRASKA. THE SEVERE THREAT TONIGHT WILL BE RATHER LIMITED AND CONFINED TO FAR NORTHWESTERN PORTIONS OF THE CWA. DEEP LAYER SHEAR WILL BE ON THE ORDER OF 15 TO 25 KTS THIS AFTERNOON...INCREASING TO 30 TO 40 KTS TONIGHT. MID LEVEL LAPSE RATES CONTINUE TO BE STEEP OVERNIGHT...SO THERE IS THAT CONTINUED THREAT FOR LARGE HAIL. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 344 AM CDT FRI MAY 6 2016 MODELS HAVE SHIFTED THE POTENTIAL FOR SEVERE TSTMS BACK NORTHWARD INTO SOUTHWEST NEBRASKA SATURDAY AFTERNOON AND EVENING. GFS AND HI RES MODELS ...NAM 4KM...NAM...ARW AND NMM ALL AGREE THAT SFC LOW PRESSURE WILL QUICKLY DEEPEN ACROSS NORTHEAST COLORADO DURING THE DAY IN RESPONSE TO A SIGNIFICANT SHORTWAVE ROUNDING THE BASE OF THE UPPER LEVEL LOW AND EMERGING INTO EASTERN COLORADO SATURDAY AFTERNOON AT PEAK HEATING. A WARM FRONT WILL BE LOCATED EAST OF THE SFC LOW ALONG A LINE FROM NEAR IMPERIAL TO CURTIS AND THEN FARTHER EAST INTO SOUTH CENTRAL NEBRASKA...WHILE A DRY LINE WILL ARC SOUTH FROM THE SFC LOW FROM FAR NORTHEAST COLORADO THROUGH EXTREME WESTERN KANSAS. THIS WILL SET UP A TRIPLE POINT IN THE VICINITY OF FAR NORTHEAST COLORADO OR FAR SOUTHWEST NEBRASKA. IT APPEARS THAT CONVECTION WILL INITIATE NEAR THE TRIPLE POINT BY LATE AFTERNOON SATURDAY...WITH OTHER SCT STORMS DEVELOPING SOUTHWARD ALONG THE DRY LINE. THE STORMS NEAR THE TRIPLE POINT SHOULD QUICKLY EXPAND EAST AND NORTHEAST ALONG AND NORTH OF THE WARM FRONT ACROSS SOUTHWEST NEBRASKA SATURDAY EVENING. POINT SOUNDINGS IN THIS AREA SHOW CONDITIONS QUITE UNSTABLE DUE TO ADEQUATE POOLED MOISTURE /DEW POINTS NEARING 60F/ STEEP MID LEVEL LAPSE RATES AND SFC TEMPS IN THE UPPER 60S TO LOWER 70S. WIND PROFILES IN THE SOUNDINGS SUPPORT SUPERCELLS WITH ALL MODES OF SEVERE POSSIBLE INCLUDING LARGE HAIL AND POSSIBLY A TORNADO OR TWO. THIS SITUATION WILL BE MONITORED CLOSELY AS THE POSITION OF THE SFC LOW AND ASSOCIATED BOUNDARIES WILL BE KEY TO WHERE THE BEST SEVERE POTENTIAL WILL RESIDE. FORECAST CONFIDENCE REGARDING THE POTENTIAL FOR SEVERE WEATHER IS LOW FOR SUNDAY. BOUNDARY LOCATION ETC. WILL LIKELY DEPEND ON SATURDAY NIGHT NIGHT CONVECTION. SEEMS REASONABLE THAT AN MCS WILL LIKELY HAVE MOVED ACROSS MOST OF THE AREA TO THE NORTH OF THE WARM FRONT SATURDAY NIGHT...AND THIS COULD VERY WELL PUSH THE FRONTAL BOUNDARY AND CORRESPONDING SEVERE THREAT FARTHER SOUTH IN KS SUNDAY AFTERNOON. HOWEVER...THE UPPER LEVEL LOW IS FORECAST TO SLOWLY CROSS THE AREA SUNDAY AFTERNOON THROUGH MONDAY. AT THE VERY LEAST EXPECT A SCATTERING OF SHOWERS AND TSTMS SUNDAY THROUGH MONDAY...WITH LATER FORECASTS TO DETERMINE THE LOCATION FOR ANY SEVERE TSTM ACTIVITY. TUESDAY AND BEYOND WILL REMAIN SOMEWHAT UNSETTLED AS ANOTHER UPPER LOW DEVELOPS INTO THE NORTHERN PLAINS. MODELS ARE CONVERGING ON A NORTHERN TRACK WITH THIS NEXT SYSTEM...WITH A MORE WESTERLY DRYING FLOW ALOFT ON THE SOUTH SIDE OF THE SYSTEM ACROSS OUR AREA. POPS HAVE TRENDED DOWN TO JUST SLIGHT CHANCE FOR MIDWEEK DUE TO THE FARTHER NORTH TRACK. IT WILL REMAIN COOL FOR MUCH OF THE WEEK...AS A PACIFIC AIRMASS WILL GRADUALLY MIX WITH A CANADIAN AIRMASS MOVING SOUTH ON THE BACKSIDE OF THE NORTHERN PLAINS UPPER LEVEL LOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1221 PM CDT FRI MAY 6 2016 VFR IS GENERALLY EXPECTED THIS AFTERNOON THROUGH SATRUDAY MORNING. ISOLATED SHOWERS AND THUNDERSTORMS CAPABLE OF GUSTY WINDS ARE INDICATED BY THE RAP AND HRRR MODELS THIS EVENING. THIS ACTIVITY IS EXPECTED TO DIMINISH BY 06Z. THE LATEST NAM MODEL RUN SHOWS MUCH LESS STORM COVERAGE. THUS ISOLATED STORM COVERAGE IS ALL THAT IS EXPECTED LATE TONIGHT AND SATURDAY MORNING. && .HYDROLOGY... ISSUED AT 344 AM CDT FRI MAY 6 2016 MINOR FLOODING CONTINUES ALONG THE NORTH PLATTE RIVER NEAR LEWELLEN. THE CURRENT STAGE AT LEWELLEN IS 7.6 FEET WHICH IS JUST OVER THE FLOOD STAGE OF 7.5 FEET. LITTLE CHANGE IN THE RIVER LEVEL IS EXPECTED OVER THE NEXT SEVERAL DAYS. ELEVATED RIVER LEVELS WILL CONTINUE ALONG THE SOUTH PLATTE RIVER AND THE MAIN STEM OF THE PLATTE RIVER DOWNSTREAM OF NORTH PLATTE FOR THE NEXT SEVERAL DAYS. AT THIS TIME...THE SOUTH PLATTE AND MAIN STEM PLATTE RIVER FROM NORTH PLATTE TO BRADY IS EXPECTED TO REMAIN BELOW FLOOD STAGE. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BUTTLER SHORT TERM...BUTTLER LONG TERM...TAYLOR AVIATION...CDC HYDROLOGY...BUTTLER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1218 PM CDT FRI MAY 6 2016 .UPDATE... ISSUED AT 558 AM CDT FRI MAY 6 2016 ISOLATED THUNDERSTORMS HAVE EXPANDED A LITTLE IN COVERAGE ACROSS SOUTHEAST SOUTH DAKOTA...AND MAY CLIP KNOX/CEDAR COUNTIES EARLY THIS MORNING. NO MODEL HAD A REAL HANDLE ON THIS...WITH MOST RECENT RUNS OF THE OPERATIONAL HRRR FINALLY CATCHING ON BY 09Z. NOTHING MORE THAN A PASSING SPRINKLE...MAYBE WITH A RUMBLE OF THUNDER. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 252 AM CDT FRI MAY 6 2016 QUIET AND VERY WARM WEATHER TODAY...THEN MORE ACTIVE AND WET WEATHER SATURDAY AND SUNDAY. UPPER RIDGE REMAINS FIRM ACROSS THE WESTERN HIGH PLAINS WITH CLOSED LOWS ACROSS BOTH COASTS. THIS RESULTS IN ONE MORE DRY DAY WITH BREEZY SOUTHERLY WINDS DEVELOPING TODAY WITH MOSTLY SUNNY SKIES. GUIDANCE REMAINS VERY WARM TODAY WITH HIGHS PROBABLY REACHING THE LOWER TO MID 80S. THIS WILL RESULT IN AFTERNOON HUMIDITY DROPPING INTO THE UPPER 20S TO LOWER 30S...BUT STILL TOO HIGH FOR ANY RED FLAG FIRE CONCERNS. THESE HIGHS ARE ALSO WELL BELOW ANY MAX TEMP RECORDS TODAY WHICH RANGE FROM 95 TO 101. THERE IS A COLD FRONT MOVING OUT OF THE NORTHERN ROCKIES...AND WILL CONTINUE TO BE PUSHED BY AN UPPER TROUGH MOVING THROUGH CENTRAL CANADA. THIS FRONT SETTLES SOUTHWARD INTO THE FORECAST AREA TOWARD I80 THROUGH DAYBREAK SATURDAY. THIS COULD RESULT IN A SLIGHT CHANCE OF THUNDERSTORMS GENERALLY ALONG/NORTH OF IT AFTER MIDNIGHT. PRECIP COULD VERY WELL EVEN REMAIN JUST NORTH OF THE AREA TONIGHT ACROSS SOUTHERN SOUTH DAKOTA. SATURDAY...THE FRONT SETTLES A LITTLE FURTHER SOUTH BUT NOT MUCH. THIS SETS UP A PRETTY TIGHT TEMPERATURE GRADIENT FROM SOUTH TO NORTH. HIGHS NORTH OF THE FRONT IN THE MID 60S...BUT NEAR 80 ALONG THE KS/NE BORDER. THERE COULD BE ISOLATED REMNANTS FROM ANY CONVECTION NORTH OF THE BOUNDARY SATURDAY MORNING. BUT...AGAIN IT COULD ALSO BE DRY AS UPPER RIDGING REMAINS IN PLACE...WITH NO SIGNIFICANT FORCING OTHERWISE. WITH THE FRONT BECOMING STATIONARY ACROSS SOUTHERN NEBRASKA SATURDAY AFTERNOON...INSTABILITY DOES BUILD NEAR IT. A WEAK CAP MAY HOLD WITH CONVECTION DEVELOPING FURTHER WEST ACROSS THE WESTERN HIGH PLAINS. WILL MAINTAIN A SLIGHT CHANCE OF THUNDERSTORMS SATURDAY AFTERNOON...BUT MOST AREAS WILL PROBABLY REMAIN DRY. IF A STORM WOULD DEVELOP...THERE IS JUST A MARGINAL RISK THAT IT COULD BE SEVERE. SATURDAY NIGHT NIGHT...ELEVATED CONVECTION MAY DEVELOP NORTH OF THE SURFACE FRONT AS DEPICTED BY VARIOUS MODELS. HOWEVER...THE NAM IS ALSO HINTING THAT A WEAK PIECE OF ENERGY EJECTING FROM THE MAIN LOW ACROSS THE CENTRAL ROCKIES MAY BE ENOUGH TO TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS. THUS WILL MAINTAIN CHANCE POPS SATURDAY NIGHT. SUNDAY IS TRICKY AS MODEL ARE NOT IN GOOD AGREEMENT ON PLACEMENT OF CONVECTION THROUGH THE DAY. THERE COULD BE LINGERING ACTIVITY EARLY SUNDAY MORNING. STRONGER STORMS COULD DEVELOP SUNDAY AFTERNOON AS LOW LEVEL MOISTURE CONTINUES TO BUILD WITH DEWPOINTS RISING INTO THE MID TO UPPER 50S AND POSSIBLY EVEN LOWER 60S. ANY MORNING CONVECTION COULD HAVE IMPLICATIONS ON AFTERNOON DEVELOPMENT... THUS CONFIDENCE IS LOW OF THE DETAILS AT THIS POINT. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 252 AM CDT FRI MAY 6 2016 PRECIP CHANCE SUBSTANTIALLY INCREASE SUNDAY NIGHT AS UPPER LOW BEGINS TO MOVE ONTO THE PLAINS AND FRONTAL BOUNDARY SHIFTS NORTHWARD ACROSS THE FORECAST AREA. WILL HAVE TO WATCH FOR SEVERE STORMS SUNDAY EVENING...AND MAYBE EVEN OVERNIGHT AS ELEVATED STORMS WILL STILL BE POSSIBLE. ONE HALF TO ONE AND ONE HALF INCHES OF RAIN WILL ALSO BE POSSIBLE SUNDAY NIGHT ACROSS THE REGION. PW VALUES INCREASE TO ABOUT 1.5 STANDARD DEVIATIONS ABOVE NORMAL BASED ON NAEFS CLIMATOLOGY DURING THIS TIME. THUNDERSTORM CHANCES REMAIN IN THE LIKELY CATEGORY THROUGH MONDAY AS SURFACE LOW/FRONTAL BOUNDARY REMAIN IN THE REGION. COULD ALSO BE A SEVERE RISK ON MONDAY AS WELL...WITH PRECIP THREAT CONTINUING INTO MONDAY NIGHT AS THE FRONT SHIFTS EASTWARD. TUESDAY WILL MAINTAIN A SMALL CHANCE OF SHOWERS/ISOLATED STORMS BASED ON OLDER MODEL BLENDS...BUT REALLY THE NEWER MODELS ARE SHOWING IT COULD BE DRY AS WE ARE BETWEEN SYSTEMS. ANOTHER WEAK WAVE COULD MOVE INTO THE AREA ON WEDNESDAY WHICH MAY BRING ONE MORE SMALL CHANCE OF SHOWERS/ISOLATED STORMS...WITH DRY WEATHER THURSDAY. && .AVIATION...(18Z TAFS FOR KOMA...KLNK...KOFK THROUGH 18Z SATURDAY) ISSUED AT 1210 PM CDT FRI MAY 6 2016 GUSTY SWLY WINDS HAVE DEVELOPED EARLY THIS AFTERNOON WITH THE ONSET OF DEEPER BOUNDARY-LAYER MIXING. A GRADUAL WEAKENING AND BACKING OF THE WINDS WILL OCCUR THIS EVENING AS THE BOUNDARY LAYER DECOUPLES. A COLD FRONT PRESENTLY FROM THE ND-MN RED RIVER VALLEY TO E-CNTRL WY WILL CONTINUE SWD...REACHING KOFK LATE TONIGHT AND KOMA AND KLNK BEFORE NOON SATURDAY. SURFACE WINDS WILL TRANSITION FROM SLY TO NELY OR ELY WITH THE FRONTAL PASSAGE. A MODEST WLY NOCTURNAL LLJ IS ALSO EXPECTED TO DEVELOP TONIGHT ACROSS PORTIONS OF E-CNTRL AND SERN NE...WITH THE POTENTIAL FOR LLWS THROUGH SUNRISE SATURDAY AT KOMA AND KLNK. VFR CIGS/VSBYS WILL PREVAIL THROUGH THE TAF PERIOD. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ UPDATE...DEWALD SHORT TERM...DEWALD LONG TERM...DEWALD AVIATION...MEAD
AREA FORECAST DISCUSSION
NWS MEDFORD OR
314 PM PDT FRI MAY 6 2016 .SHORT TERM...TODAY THROUGH SATURDAY NIGHT... HIGH CLOUDS FROM CONVECTION ACROSS NEVADA THIS MORNING HAVE OVERSPREAD MUCH OF THE AREA THIS AFTERNOON. WHILE THIS HAS LIMITED SURFACE HEATING SOME TODAY, SOME SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS PORTIONS OF LAKE, MODOC, AND SISKIYOU COUNTIES. THUS FAR, SOME ONE HOUR RAINFALL AMOUNTS OF 0.20 TO 0.30" HAVE BEEN OBSERVED WITH THESE CELLS IN MODOC AND SISKIYOU COUNTIES. WITH STORMS MOVING SOUTHWEST AROUND 30 MPH SOME GUSTY WINDS ARE POSSIBLE. HOWEVER, AT THIS TIME NONE OF THE ACTIVITY IS THREATENING TO REACH SEVERE THRESHOLDS OVER THE NEXT HOUR. WHAT APPEARS TO A BIT OF A CONCERN AS WE HEAD THROUGH THE AFTERNOON INTO THE EVENING IS THE POSSIBILITY OF TRAINING SHOWER AND THUNDERSTORM ACTIVITY ACROSS SOME OF THESE SAME AREAS. ALSO, EXTENSIVE HEAVIER SHOWERS AND THUNDERSTORMS ACROSS NORTHERN NEVADA ARE LIKELY TO BRING AN EXTENSIVE AREA OF RAINFALL ACROSS THE SOUTHEAST SIDE THIS EVENING, PROBABLY IN EXCESS OF A HALF OF AN INCH ACROSS MUCH OF MODOC COUNTY. THUS, THE PRIMARY CONCERN THROUGH THIS EVENING WILL BE URBAN AND SMALL STREAM FLOODING, POSSIBLE FLOODING ON AND NEAR BURN SCAR AREAS FROM RECENT YEARS, AND, SHOULD THIS HEAVY RAIN STALL OVER SNOWPACK AREAS, MORE EXTENSIVE FLOODING WILL BE POSSIBLE. WHILE SEVERE WIND AND HAIL IS STILL A THREAT THROUGH THE EVENING SUSPECT IT WILL BE ISOLATED AT MOST DUE TO THE FACT THAT SHORTWAVE ENERGY AND SURFACE DYNAMICS TO SUPPORT IT ARE FAIRLY WEAK. 500MB TEMPERATURES ARE GENERALLY WARMING THIS AFTERNOON AND EVENING. HAVE USED THE HRRR FOR MANY OF THE FORECAST REFINEMENTS TODAY, BUT HAVE ALSO ADJUSTED THAT AS OBSERVED CONDITIONS ARE A BIT DIFFERENT. FOR THE WEST SIDE THERE IS STILL SOME THREAT OF SHOWERS AND ISOLATED THUNDERSTORMS, ALBEIT LESS THAN THE EAST SIDE AND NORTHERN CALIFORNIA, AS THE DYNAMICS ARE NOT AS FAVORABLE. TONIGHT THROUGH SATURDAY SHOWER AND THUNDERSTORM ACTIVITY WILL WEAKEN AND THEN RE-FIRE AGAIN. HOWEVER, INSTABILITY IS LESSER TOMORROW AS THE UPPER LEVEL LOW WILL BE FURTHER SOUTH AND EAST. THIS WILL BE PARTIALLY COUNTERACTED BY INCREASED SURFACE HEATING DUE TO LESS CLOUD COVER. WHILE MOST GUIDANCE KEEPS SHOWERS AND STORMS EAST OF THE CASCADES, THE SREF AND NAM12 DO SUPPORT SOME POTENTIAL ALONG AND NEAR THE CASCADES. LOCALIZED HEAVY RAINFALL WILL STILL BE OF SOME CONCERN AS PWATS WILL BE 0.75" TO JUST OVER 1 INCH- SIMILAR TO TODAY. BTL .LONG TERM...SUNDAY THROUGH FRIDAY... THE UPPER LOW WILL CONTINUE TO SLOWLY MOVE INTO THE FOUR CORNERS SUNDAY MORNING AND AN UPPER RIDGE WILL NOSE IN FROM THE WEST, BUT THEN WILL RETREAT WESTWARD SUNDAY AFTERNOON AS A SHORTWAVE MOVES SOUTHEAST INTO EASTERN WASHINGTON. AT THE SURFACE A WEAK FRONT WILL MOVE THROUGH THE NORTHWEST PART OF THE REGION EARLY SUNDAY MORNING INCREASING THE ONSHORE FLOW. THE MARINE LATER COULD THICKEN ENOUGH TO WARRANT A SLIGHT CHANCE OF LIGHT RAIN OR DRIZZLE MAINLY NORTH OF THE UMPQUA DIVIDE. COULD NOT RULE OUT A SLIGHT CHANCE IN PARTS OF THE ILLINOIS VALLEY, GRANTS PASS AND THE NORTH END OF THE ROGUE VALLEY. ELSEWHERE IT WILL REMAIN DRY. ANOTHER SHORTWAVE WILL MOVE INTO EASTERN WASHINGTON AND NORTHEAST OREGON ON MONDAY, BUT THE TRACK IS NOT FAVORABLE FOR PRECIPITATION, SO IT WILL REMAIN DRY. AN UPPER RIDGE WILL BUILD OFF THE COAST TUESDAY WITH A THERMAL TROUGH DEVELOPING AT THE COAST. THE MODELS DIFFER WITH THE DETAILS AFTER TUESDAY, BUT CONDITIONS ARE EXPECTED TO REMAIN DRY WITH ABOVE NORMAL TEMPERATURES IN THE AFTERNOON. THEREFORE, FORECAST HIGH TEMPERATURES WERE INCREASED FOR THE TUESDAY THROUGH THURSDAY TIME PERIOD. THE MODELS SHOW AN UPPER LOW MOVING TOWARDS THE CALIFORNIA COAST LATE NEXT WEEK WHICH COULD BRING INCREASING MOISTURE AND INSTABILITY, BUT IT`S STILL A WAYS OUT AND THE DETAILS ARE LIKELY TO CHANGE. FOR NOW WE`LL KEEP IT DRY WITH ABOVE NORMAL TEMPERATURES. -PETRUCELLI && .AVIATION...FOR THE 06/18Z TAF CYCLE...THE MAIN CONCERN INTO THIS EVENING WILL BE ISOLATED TO SCATTERED THUNDERSTORMS. ANY STORMS WILL BE CAPABLE OF PRODUCING MVFR AND OCCASIONAL IFR CIGS, VERY HEAVY RAIN, SMALL HAIL AND GUSTY OUTFLOW WINDS. SHOWERS AND THUNDERSTORMS WILL START OUT ISOLATED EARLY THIS AFTERNOON, THEN WILL BECOME MORE NUMEROUS FROM LATE THIS AFTERNOON INTO THIS EVENING WITH A GENERAL MOVEMENT FROM EAST TO WEST, THEN NORTHEAST TO SOUTHWEST TOWARDS THIS EVENING. THE GREATEST THREAT FOR THUNDERSTORMS IS FROM THE CASCADES/SISKIYOUS EAST, BUT STORMS MAY ADVANCE AS FAR WEST AS JACKSON COUNTY (INCLUDING KMFR) LATE THIS AFTERNOON. SHOWERS AND STORMS DIMINISH LATE THIS EVENING WITH VFR CONDITIONS EXPECTED, EXCEPT FOR THE COAST WHERE MVFR AND LOCAL IFR CIGS WILL DEVELOP EARLY THIS EVENING AND CONTINUE INTO SATURDAY MORNING. -PETRUCELLI && .MARINE...UPDATED 500 AM PDT FRI 6 MAY 2016...FEW CHANGES WERE MADE TO THE MARINE FORECAST THIS MORNING. NORTH WINDS WILL INCREASE AGAIN THIS AFTERNOON AND CONTINUE INTO THE EVENING. THIS TREND OF STRONG NORTH WINDS/STEEP SEAS IN THE AFTERNOON/EVENINGS AND LULLS AT NIGHT WILL LIKELY CONTINUE THROUGH THE WEEKEND. A GALE WARNING REMAINS IN EFFECT THROUGH THIS EVENING OVER THE SOUTHERN WATERS WITH SMALL CRAFT ADVISORIES ELSEWHERE. MODELS HAVE MAINTAINED THE POTENTIAL FOR GALES OVER THE WEEKEND AND GALE WATCHES REMAIN IN EFFECT. THESE WILL LIKELY BE UPGRADED LATER TODAY. -WRIGHT && .MFR WATCHES/WARNINGS/ADVISORIES... OR...FLASH FLOOD WATCH UNTIL 11 PM PDT THIS EVENING FOR ORZ030-031. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS EVENING FOR ORZ022. CA...FLASH FLOOD WATCH UNTIL 11 PM PDT THIS EVENING FOR CAZ080>085. PACIFIC COASTAL WATERS... - SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ350-356-370-376. - SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS EVENING FOR PZZ350-356-370. - GALE WARNING UNTIL 11 PM PDT THIS EVENING FOR PZZ356-376. - GALE WATCH FROM SATURDAY MORNING THROUGH SUNDAY EVENING FOR PZZ376. $$ BTL/MAP/DW
AREA FORECAST DISCUSSION
NWS MEDFORD OR
1059 AM PDT FRI MAY 6 2016 .UPDATE... AN UPDATE TO THE FORECAST HAS BEEN MADE AND SENT FOR CONDITIONS THROUGH THIS EVENING. ADJUSTMENTS WERE MADE TO SKY COVERAGE, PROBABILITY OF PRECIPITATION, PRECIPITATION AMOUNTS, SHOWER AND THUNDERSTORM COVERAGE, AND LIGHTNING ACTIVITY LEVEL. && .DISCUSSION... LOW PRESSURE CENTERED OVER CALIFORNIA AND NEVADA THIS MORNING IS SENDING INVERTED TROUGHS ACROSS THE FORECAST AREA FROM EAST TO WEST TODAY. PRIMARY FOCUS FOR SHOWER AND THUNDERSTORM ACTIVITY WILL BE ACROSS MODOC, LAKE, SISKIYOU, AND KLAMATH COUNTIES THIS AFTERNOON AND EVENING. SOME ACTIVITY IS LIKELY TO REACH TO THE SOUTHEASTERN PORTION OF THE WEST SIDE LATE THIS AFTERNOON AND, MORE LIKELY, THIS EVENING FROM ABOUT CRATER LAKE NATIONAL PARK SOUTHWESTWARD TO THE BEAR CREEK PORTION OF THE ROGUE VALLEY, OREGON CAVES, AND THE LOWER KLAMATH RIVER VALLEY. FLASH FLOOD WATCHES REMAIN IN EFFECT FOR PORTIONS OF THE EAST SIDE AND NORTHERN CALIFORNIA FOR THIS AFTERNOON THROUGH THIS EVENING. BTL && .AVIATION...FOR THE 06/12Z TAF CYCLE...A MIX OF MVFR AND VFR CONDITIONS WILL CONTINUE THROUGH LATE MORNING. SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EAST SIDE EARLY THIS AFTERNOON AND THEN MOVE FROM EAST TO WEST ACROSS THE AREA. THE GREATEST THREAT FOR THUNDERSTORMS IS FROM THE CASCADES/SISKIYOUS EAST, BUT STORMS MAY ADVANCE AS FAR WEST AS JACKSON/JOSEPHINE COUNTY (INCLUDING KMFR) LATE THIS AFTERNOON. ANY STORMS WILL BE CAPABLE OF PRODUCING IFR CIGS/VIS, VERY HEAVY RAIN, SMALL HAIL, AND GUSTY WINDS. SHOWERS AND STORMS DIMINISH LATE THIS EVENING. -WRIGHT && .MARINE...UPDATED 500 AM PDT FRI 6 MAY 2016...FEW CHANGES WERE MADE TO THE MARINE FORECAST THIS MORNING. NORTH WINDS WILL INCREASE AGAIN THIS AFTERNOON AND CONTINUE INTO THE EVENING. THIS TREND OF STRONG NORTH WINDS/STEEP SEAS IN THE AFTERNOON/EVENINGS AND LULLS AT NIGHT WILL LIKELY CONTINUE THROUGH THE WEEKEND. A GALE WARNING REMAINS IN EFFECT THROUGH THIS EVENING OVER THE SOUTHERN WATERS WITH SMALL CRAFT ADVISORIES ELSEWHERE. MODELS HAVE MAINTAINED THE POTENTIAL FOR GALES OVER THE WEEKEND AND GALE WATCHES REMAIN IN EFFECT. THESE WILL LIKELY BE UPGRADED LATER TODAY. -WRIGHT && .PREV DISCUSSION... /ISSUED 339 AM PDT FRI MAY 6 2016/ DISCUSSION...A MOIST AND UNSTABLE AIR MASS CONTINUES OVER MUCH OF THE FORECAST AREA TODAY...AND WILL HELP GENERATE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS...PRIMARILY FOCUSED OVER NORTHERN CALIFORNIA AND FROM THE CASCADES EASTWARD. THE CUTOFF LOW THAT DOESN`T QUIT REMAINS OVER SOUTHERN CALIFORNIA...SLOWLY MOVING TO THE EAST AND FEEDING THE AREA WITH DEEP MOISTURE AND DISTURBANCES FROM THE SOUTHEAST. THE INTERSECTION OF DEEP MOISTURE...INSTABILITY...AND FAVORABLE DYNAMICS WILL BE MOST PROMINENT IN EASTERN SISKIYOU...MODOC...AND LAKE COUNTIES TODAY. THE WRF ARW AND NMM SHOW STORMS AND HEAVY RAINFALL FROM MOUNT SHASTA EASTWARD TO ALTURAS AND NORTHEAST TO LAKEVIEW THIS AFTERNOON AND EVENING AS SHORTWAVE ENERGY MOVES IN FROM THE EAST PER THE NAM AND SREF MODEL OUTPUT. THE LATEST HRRR OUTPUT IS SUGGESTING SIMILAR. GIVEN CURRENT SNOW DEPTH OVER THE WARNER MOUNTAINS OF 62 INCHES PER DISMAL SWAMP SNOTEL...AND FORECAST SNOW LEVELS OF 9500 FEET...THIS DEFINITELY PROVIDES THE POTENTIAL FOR RAPID SNOW MELT AND FLASH FLOODING. A FLASH FLOOD WATCH CONTINUES FOR THE SOUTHERN HALF OF SISKIYOU COUNTY...MODOC...EXTREME EASTERN KLAMATH...AND MOST OF LAKE COUNTY. PRECIPITABLE WATER VALUES IN THE TOP 10 PERCENT FOR THIS TIME OF YEAR ALSO SUPPORT THE FFA AREA. THE WESTERN FRINGES OF THIS HAZARD AREA ARE LESS LIKELY TO SEE ANY HEAVY RAIN PROBLEMS BUT HAVE LEFT THE AREA INTACT FROM THE PREVIOUS ISSUANCE GIVEN THE UNCERTAINTY OF EXACT HEAVY RAIN LOCATIONS...AND WITH LATEST HRRR OUTPUT LINING UP PRETTY NICELY WITH THE HAZARD AREA. ADDITIONALLY...THE STORM PREDICTION CENTER HAS MAINTAINED A MARGINAL RISK FOR SEVERE STORMS OVER MODOC AND SOUTHERN LAKE COUNTIES. EASTERN SISKIYOU COUNTY ALSO FEATURES A CHANCE FOR SEVERE THUNDERSTORMS WITH FORECAST MOST UNSTABLE CAPES OF 2000+ J/KG, LI VALUES -4 TO -6, AND 0-6KM BULK SHEAR VALUES OF 30+KT. STRONG WINDS, HAIL, AND HEAVY RAIN ARE ALL A POSSIBILITY TODAY. LATEST SATELLITE IMAGERY SHOWS THAT THE DAY SHOULD START OUT SUNNY IN MANY PLACES EAST OF THE CASCADES...WHICH WILL YIELD UNINHIBITED SURFACE HEATING AND POTENTIALLY MAX OUT THE INSTABILITY THIS AFTERNOON. INSTABILITY DIMINISHES TONIGHT AND SHOWERS AND THUNDERSTORMS FOLLOW SUIT. ON SATURDAY A DRYING AIR MASS WEST OF THE CASCADES WILL YIELD SUNNY AND WARM CONDITIONS WHILE THUNDERSTORMS REMAIN POSSIBLE IN MODOC COUNTY. TEMPERATURES WILL BE ABOUT 10 DEGREES ABOVE NORMAL WEST OF THE CASCADES. BY SUNDAY COOL AND DRY NORTHWEST FLOW ALOFT ELIMINATES THE CHANCE FOR SHOWERS OVER THE VAST MAJORITY OF THE FORECAST AREA...WHILE A DEEPENING MARINE LAYER COULD BRING DRIZZLE TO THE COAST. ON MONDAY A WARM TREND BEGINS THAT WILL LAST INTO THE MIDDLE OF THE WEEK AT LEAST...WITH TEMPERATURES MONDAY EXPECTED TO BE A FEW DEGREES ABOVE NORMAL. A PORTION OF THE PREVIOUS LONG-TERM DISCUSSION FOLLOWS. TUESDAY THROUGH THURSDAY...AN UPPER RIDGE WILL BUILD OFF THE COAST TUESDAY WITH A THERMAL TROUGH DEVELOPING AT THE COAST. THE MODELS DIFFER WITH THE DETAILS AFTER TUESDAY, BUT THE PATTERN REMAINS FAVORABLE FOR CONTINUED DRY AND WARM CONDITIONS. -PETRUCELLI && .MFR WATCHES/WARNINGS/ADVISORIES... OR...FLASH FLOOD WATCH THROUGH THIS EVENING FOR ORZ030-031. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS EVENING FOR ORZ022. CA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR CAZ080>085. PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ350-356-370-376. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS EVENING FOR PZZ350-356-370. GALE WARNING UNTIL 11 PM PDT THIS EVENING FOR PZZ356-376. GALE WATCH FROM SATURDAY MORNING THROUGH SUNDAY EVENING FOR PZZ376. $$ BTL/NSK/TRW
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
607 PM EDT FRI MAY 6 2016 .SYNOPSIS... SHOWERS REMAIN IN THE FORECAST THROUGH SATURDAY. MOTHERS DAY LOOKS MAINLY DRY FOLLOWED BY A MODEST WARMING TREND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... MAIN BAND OF RAIN SHOWERS MOVING THROUGH MUCH OF CENTRAL PA ATTM. SHOWERS WILL PERSIST THROUGH THE EARLY EVE HOURS BEFORE TAPERING OFF TO DRIZZLE MOST PLACES. DRIZZLE ALONG WITH AREAS OF FOG AND LOW CLOUDS WILL PERSIST OVERNIGHT AS SFC LOW PULLS AWAY FROM THE REGION. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... THE UPPER LOW WILL DRIFT NWD AND HOVER OVER THE EASTERN HALF OF THE STATE TONIGHT BEFORE FILLING AND GETTING KICKED OUT TO SEA BY AN ANOMALOUS TROUGH MOVING IN FROM THE WNW ON SAT. THERE MIGHT BE A LULL IN THE PRECIP ON SAT IN BETWEEN THE SYSTEMS. THE UPSTREAM TROUGH WILL MANAGE TO NUDGE SOME SEASONABLY MILD AIR IN FROM THE SW. MAXES SHOULD BE IN THE 60S AREAWIDE. THIS SHOULD HELP GENERATE SOME INSTABILITY AND CAPE...ALLOWING CONVECTION TO FORM ALONG AND JUST IN ADVANCE OF THE LOW/FRONT. WILL JUST MENTION SOME TS IN THE LATE AFTN IN THE W AND CARRY IT INTO THE CENTRAL MTNS FOR THE FIRST PART OF SAT NIGHT BEFORE THE FRONT PUSHES THRU. AGAIN...MOISTURE STILL LACKING AND THE WESTERLY FLOW AHEAD OF THE FRONT WILL KEEP THE RAINFALL TO A RELATIVE MINIMUM. LITTLE/NO RISK FOR BOTH SEVERE AND FLOODING. THE 8H TEMPS FROM 10-12C DOWN TO AROUND A FEW DEGS EITHER SIDE OF 0C BY SUNDAY MORNING. && .LONG TERM /SUNDAY THROUGH FRIDAY/... SFC COLD FRONT WILL PUSH SE ACROSS THE STATE EARLY SUNDAY... ACCOMPANIED BY A FEW SCATTERED SHOWERS. MODERATELY STRONG LLVL PRESSURE GRADIENT AND COLD ADVECTION WILL BRING GUSTY NW WINDS (PEAK GUSTS OF 25-30 MPH DURING THE LATE MORNING AND AFTERNOON HOURS) WITH PARTLY TO MOSTLY SUNNY SKIES. SFC RIDGE AXIS WITH LOW PWAT AIR SLIDES OVER THE STATE LATER SUNDAY NIGHT WITH CLEAR TOO PARTLY CLOUDY SKIES AND CHILLY LOW TEMPS EARLY MONDAY - IN THE 30S AND 40S. PATCHY LIGHT FROST IS POSSIBLE ACROSS THE NRN MTNS 05-12Z MONDAY. THE SFC RIDGE WILL SLIDE TO OUR EAST BY MONDAY NIGHT AS HEIGHTS SLOWLY BEGIN TO RISE ALOFT. THIS WILL HELP TO FORM/ADVECT A WARM FRONT NE FROM THE OHIO VALLEY TO CENTRAL PA BY TUESDAY AFTERNOON. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO DEVELOP MONDAY AFTERNOON AND EVENING ACROSS MAINLY THE WRN MTNS OF THE STATE...AND WILL PERSIST AT ABOUT THE SAME AREAL COVERAGE INTO TUESDAY MORNING. CHC FOR SHOWERS (AND SCATTERED TSRA) INCREASES TUESDAY AFTERNOON AND NIGHT AS SWRLY LLJ TRANSPORTS BETTER MOISTURE INTO THE REGION...AND UPPER LEVEL DIVERGENCE STRENGTHENS. CHC FOR PRECIP IN THE FORM OF SHOWERS AND SCATTERED TSRA WILL PEAK DURING THE MIDWEEK PERIOD...BEFORE THE SFC FRONT BEGINS TO OCCLUDE AND WEAKEN AS THE UPPER FLOW TURNS MORE ZONAL. LATER NEXT WEEK AND OVER NEXT WEEKEND...NRN STREAM ENERGY WITH DIFFICULT TO TIME JETLETS TO ITS SOUTH WILL BRING LOW CHCS FOR MAINLY AFTERNOON SHOWERS AND ISOLATED TSRA. TEMPS WILL START OUT A FEW TO SEVERAL DEG F BELOW NORMAL SUNDAY INTO MONDAY...THEN GRADUALLY MODERATE TO NEAR OR SLIGHTLY ABOVE NORMAL DURING THE MID-WEEK PERIOD AS THE SOUTHERN STREAM WAVE PUSHES THE AFOREMENTIONED WARM INTO...OR JUST NORTH OF THE REGION. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... LOW PRES OVR THE DELMARVA PENINSULA WILL WEAKEN OVERNIGHT...CAUSING RAIN TO TAPER OFF ACROSS MOST OF CENTRAL PA. HOWEVER...STRATUS DECK WILL REMAIN IN PLACE AND CIGS SHOULD FALL OVERNIGHT AS BLYR COOLS. VFR CIG STILL NOTED AT KBFD AS OF 22Z...BUT MDL SOUNDINGS SUPPORT A DROP TO MVFR BY 00Z. BOTH SREF AND LATEST HRRR SUGGEST IFR CIGS ARE LIKELY LATE TONIGHT AT KMDT/KLNS...POSSIBLE AT KBFD/KJST/KUNV AND UNLIKELY AT KIPT. REMNANTS OF LOW PRES WILL PUSH OUT TO SEA AND RESIDUAL STRATUS DECK WILL LIKELY LIFT/BREAK UP BY AFTN DUE TO DIURNAL HEATING/MIXING. BOTH MOS AND SREF SUPPORT THE IDEA OF WIDESPREAD VFR CONDS BY SAT AFTN. A COLD FRONT WILL SWEEP INTO THE REGION SAT EVENING...ACCOMPANIED BY SCT SHRA AND POSSIBLE BRIEF VIS REDUCTIONS...MAINLY OVER THE WESTERN HALF OF THE STATE. OUTLOOK...SATURDAY-TUESDAY SUN-MON...VFR/NO SIG WX EXPECTED. TUE-WED...CHC OF SHOWERS/MVFR PSBL. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO/GARTNER NEAR TERM...GARTNER SHORT TERM...DANGELO/GARTNER LONG TERM...LAMBERT/STEINBUGL AVIATION...FITZGERALD/GARTNER
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
306 PM CDT FRI MAY 6 2016 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 306 PM CDT FRI MAY 6 2016 WEAK SHORT WAVE AND ATTENDANT SURFACE COLD FRONT WILL MOVING SOUTHWARD ACROSS THE FORECAST AREA TONIGHT. PRECIP CHANCES ARE A TOUGH CALL WITH THIS SYSTEM. BOTH THE NAM AND GFS HUMIDITY TIME SECTIONS AND SOUNDINGS SHOW VERY LITTLE IN THE WAY OF LOW LEVEL MOISTURE BELOW ABOUT 750MB...WITH OBVIOUSLY WELL MIXED CONDITIONS AHEAD OF THE BOUNDARY THIS AFTERNOON ADDING TO THE DRYNESS. THE FORCING WITH THE SHORT WAVE IS NOT OVERLY IMPRESSIVE...BUT THIS EVENING THERE IS A FAIR AMOUNT OF PURE ELEVATED INSTABILITY. THE WIND SHEAR IS RATHER WEAK HOWEVER...NOTED WITH 30 KNOTS AT 925MB AND ONLY 5 TO 10 KNOTS AT 700MB. INTERESTINGLY...THE HRRR CONTINUES TO DEVELOP CONVECTION LATE THIS AFTERNOON AND EARLY EVENING ALONG THE I 90 AND HIGHWAY 14 CORRIDORS. THE HIGHWAY 14 CONVECTION WOULD BE ASSOCIATED WITH LOW LEVEL CONVERGENCE ALONG THE COLD FRONT. HOWEVER THE I 90 CONVECTION IS WELL AHEAD OF THE FRONT. AM SKEPTICAL ABOUT THE I 90 CONVECTION DEVELOPING SO EARLY...AS IT IS LIKELY KEYING OFF OF THE CONVECTIVE TEMPERATURE. INDEED...THE HRRR IS TRYING TO SHOW CONVECTION DEVELOPING RIGHT NOW IN SOUTH CENTRAL SD AND THERE IS NOTHING THERE. IT IS THAT CONVECTION WHICH IT THEN EXTENDS EASTWARD ALONG I 90. SO FOR NOW ADDED ONLY VERY LOW POPS TO THE I 90 CORRIDOR VERY LATE THIS AFTERNOON AND EARLY EVENING TO ACCOUNT FOR THE HRRR SCENARIO...AND KEPT THE HIGHER SCATTERED POPS IN OUR NORTHERN ZONES CLOSER TO THE ACTUAL FRONT. CHANCE OR SCATTERED POPS SHOULD THEN DRIFT SOUTHWARD THROUGH THE NIGHT...BUT AGAIN CHANCES ARE FAIRLY SKITTISH AT ANY GIVEN POINT LOCATION THAT YOU WILL ACTUALLY GET WET. IN ADDITION...STABILITY INCREASES AFTER MIDNIGHT TO THE POINT WHERE BY SATURDAY...THERE IS LITTLE IN THE WAY OF INSTABILITY LEFT IN OUR SOUTHERN ZONES WHERE SMALL POPS LINGER UNDER A MID DECK OF CLOUDS. FOR TEMPERATURES...LATEST LOWS ARE LITTLE CHANGED FROM PREVIOUS RUNS...WITH UPPER 40S IN OUR FAR NORTHERN ZONES...TO NEAR 55 IN SIOUX CITY AND STORM LAKE IA. HIGHS SATURDAY WILL BE COOLER... WITH READINGS IN THE UPPER 60S TO AROUND 70. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 306 PM CDT FRI MAY 6 2016 SATURDAY NIGHT INTO SUNDAY WILL SEE LOW PRESSURE ALOFT DEVELOP ACROSS THE CENTRAL ROCKIES AS HIGH PRESSURE AT THE SURFACE SETTLES INTO THE NORTHERN PLAINS. THIS SHOULD ALLOW FOR MAINLY DRY CONDITIONS DURING THIS TIME. THERE WILL BE A CHANCE FOR SHOWERS CLOSER TO THE MISSOURI RIVER CORRIDOR CLOSER TO THE MID LEVEL MOISTURE...BUT CHANCES NOT REAL HIGH. EASTERLY FLOW WILL ALLOW COOLER AIR TO FILTER IN BUT BE OFFSET A BIT BY CLOUD COVER AT NIGHT. LOWS SHOULD MAINLY BE IN THE 40S...CLOSER TO 40 ALONG HIGHWAY 14 AND CLOSER TO 50 ALONG THE MISSOURI RIVER. HIGHS ON SUNDAY...WITH THE THICKER CLOUDS CLOSER TO THE MISSOURI RIVER SHOULD BE CLOSER TO THE MID 60S...WITH LOWER 70S POSSIBLE CLOSER TO HIGHWAY 14. SUNDAY NIGHT INTO MONDAY DEEPER MOISTURE AND BETTER SUPPORT FOR PRECIPITATION WILL SPREAD NORTH SO SUSPECT THAT THIS WILL BE THE PERIOD OF TIME FOR THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS. AT THIS TIME NOT ENOUGH SHEAR OR INSTABILITY TO BE CONCERNED ABOUT SEVERE WEATHER BUT ENOUGH TO CONTINUE A MENTION OF THUNDERSTORMS. DIURNAL RANGE NOT TOO WIDE WITH LOWS IN THE 50S SUNDAY NIGHT AND HIGHS IN THE LOWER TO MID 60S ON MONDAY. IN THE OUTER PERIODS(TUESDAY THROUGH FRIDAY)...DEEP TROUGHING IN THE MIDDLE OF THE COUNTRY WILL SPELL COOL AND SHOWERY WEATHER THROUGH THE PERIOD. WHILE OVERALL CONFIDENCE IN THE DEEPER TROUGH IS FAIRLY HIGH...CONFIDENCE ON THE INDIVIDUAL PIECES OF ENERGY ARE LOWER THUS THE CHANCES FOR PRECIPITATION WILL NOT BE ALL THAT HIGH. THERE SHOULD BE A FEW PERIODS OF SHOWERS AND POSSIBLY THUNDERSTORMS DURING THIS TIME JUST A PROBLEM OF TIMING. FOR NOW WILL LEAN TOWARDS ONLY A SHOWERS MENTION AND START ADDING IN THE CHANCE FOR THUNDERSTORMS WHEN CONFIDENCE INCREASES. AS FOR TEMPERATURES NOT TOO MUCH TO TALK ABOUT...PRETTY MUCH HIGHS IN THE 60S AND LOWS IN THE 40S. OVERALL NOT A REAL NICE PERIOD OF WEATHER FOR MID MAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1234 PM CDT FRI MAY 6 2016 VFR WILL PREVAIL TODAY AND TONIGHT. A COLD FRONT WILL MOVE SOUTHWARD TONIGHT CAUSING A WIND SHIFT TO A NORTHERLY...THEN NORTHEAST DIRECTION. THERE COULD BE SOME ISOLATED TSRA WITH THIS FRONTAL PASSAGE...BUT AT THIS TIME WAS LEFT OUT OF THE TAF SITES WITH THE CHANCES BEING TOO SPARSE. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...MJ LONG TERM...08 AVIATION...MJ
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
352 PM EDT FRI MAY 6 2016 .SYNOPSIS... COOL AND UNSETTLED WEATHER WILL CONTINUE ACROSS THE REGION THROUGH THE WEEKEND WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS. WARMER AIR WILL START TO WORK INTO THE REGION WITH A WARMING TREND AND MORE SEASONABLE TEMPERATURES THROUGH THE MIDDLE OF NEXT WEEK...ALTHOUGH UNSETTLED CONDITIONS WILL CONTINUE OUR CHANCES FOR SHOWERS AND THUNDERSTORMS. && .NEAR TERM /THROUGH SATURDAY NIGHT/... AS OF 345 PM EDT FRIDAY... UPPER AND SFC LOW PRESENTLY NEAR VERTICALLY STACKED OVER THE DELMARVA REGION. A SHORTWAVE ROUNDING THE EASTERN SIDE OF THE UPPER LEVEL LOW IS SPARKING SOME SHOWERY ACTIVITY IN THE REGION. THESE SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM ARE EXPECTED THROUGH THE AFTERNOON HOURS...WITH A LITTLE BIT BETTER ORGANIZED ACTIVITY ROLLING THROUGH IN THE EARLY EVENING HOURS. TOTAL RAINFALL AMOUNTS SHOULD GENERALLY BE SMALL BASED ON LATEST HRRR WHICH SHOWS MAXIMUM AMOUNTS OF A TENTH TO QUARTER OF AN INCH. DESPITE RECENT RAINS...ADDITIONAL AMOUNTS WILL NOT BE ENOUGH TO CAUSE ANY FLOOD CONCERNS ASIDE FROM THE CURRENT AND FORECAST RIVER FLOODING ALONG AND NEAR THE DAN RIVER. GIVEN ABUNDANT GROUND MOISTURE...FOG COULD BECOME A CONCERN THIS EVENING...THOUGH WINDS SHOULD STAY UP ENOUGH TO CAUSE ENOUGH MIXING TO KEEP IT FROM BECOMING WIDESPREAD. A STRENGTHENING PRESSURE GRADIENT BETWEEN THE PASSING LOW AND A SECOND ONE MOVING THROUGH THE GREAT LAKES REGION WILL INDUCE SOME STRONGER WINDS TOMORROW...HOWEVER NOTHING ABOVE 35 MPH ARE FORECAST. AHEAD OF THE COLD FRONT ASSOCIATED WITH THE LOW...SHOWERS SHOULD FIRE UP IN THE REGION...PARTICULARLY IN THE MOUNTAINS. AN ISOLATED THUNDERSTORM CAN NOT BE RULED OUT DUE TO WEAK INSTABILITY AT THE TIME THE FRONT APPROACHES THE REGION...BUT LITTLE MORE BEYOND A RUMBLE OF THUNDER IS EXPECTED. AGAIN...EXPECTED ADDITIONAL RAINFALL AMOUNTS WILL NOT BE ENOUGH TO CAUSE ANY FLOOD CONCERNS. NIGHT TIME LOWS SHOULD BE SEASONAL IN THE MID TO HIGH 40S...AND TOMORROWS HIGHS WILL BEGIN TO TREND BACK TOWARDS SEASONAL AND WILL BE IN THE 60S AND 70S. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 345 PM EDT FRIDAY... THE UPPER LEVEL PATTERN WILL BE TRANSITIONING TO SOME SHALLOW RIDGING AND EVENTUALLY SET UP SOUTHEASTERLY FLOW ALOFT...ALLOWING THE MODERATING TREND TO CONTINUE IN TEMPERATURES. HOWEVER A FRONTAL BOUNDARY WILL SETTLE INTO THE REGION ON SUNDAY AND LINGER OVER THE AREA INTO THE FIRST PART OF NEXT WEEK. THIS WILL KEEP CONDITIONS UNSETTLED WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST. ALSO AS THE FRONT INITIALLY MOVES INTO THE AREA FROM THE SATURDAY NIGHT THE LOW LEVEL WIND FIELD WILL ENHANCE AND CREATE QUITE GUSTY CONDITIONS INTO SUNDAY. HIGH TEMPERATURES BY MONDAY WILL BE AROUND 80 DEGREES EAST OF THE BLUE RIDGE AND GENERALLY IN THE 70 TO 75 DEGREE RANGE TO THE WEST. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 345 PM EDT FRIDAY... THE UPPER PATTERN WILL REMAIN TRANSITORY AND TRANSITION FROM A SHALLOW RIDGE TO A PROGRESSIVE QUASI ZONAL REGIME. THIS WILL ALLOW SOUTHEASTERLY FLOW TO CONTINUE BRINGING MOISTURE INTO THE REGION WITH AN INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH THE END OF THE WORKWEEK. TEMPERATURES WILL REMAIN SEASONABLE WITH HIGHS IN THE LOWER 80S EAST TO THE LOWER AND MIDDLE 70S WEST WITH A SLIGHT COOLDOWN BY THE END OF THE WEEK. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... AS OF 130 PM EDT FRIDAY... THE UPPER LEVEL LOW THAT CREATED POOR FLIGHT CONDITIONS FOR MUCH OF THE PAST FEW DAYS IS FINALLY EXITING THE REGION TO THE EAST. SHOWERY CONDITIONS WILL BEGIN TO FORM UP IN THE REGION THIS AFTERNOON AT PEAK HEATING. BASED ON HRRR GUIDANCE...ROA/LYH/DAN WILL SEE SOME OF THIS ACTIVITY IN THE AFTERNOON INTO THE EVENING HOWEVER CONDITIONS LOOK TO REMAIN PRIMARILY VFR. OTHER LOCATIONS...CURRENTLY FORECAST FOR VICINITY SHOWERS DUE TO LOWER CONFIDENCE. FOG WAS CONSIDERED FOR THE OVERNIGHT HOURS BUT ENOUGH MIXING SHOULD OCCUR TO ELIMINATE THAT THREAT. LYH AND DAN APPEAR TO BE AT MOST THREAT BUT WAS LEFT OUT FOR NOW DUE TO LOW CONFIDENCE. WINDS ARE CURRENTLY A BIT GUSTY AND PRIMARILY FROM THE NORTHWEST FOR MUCH OF THE REGION. THESE SHOULD CALM DOWN WITH SUNSET BUT SHOULD BEGIN AGAIN AROUND SUNRISE. LYH SHOULD BE SPARED FROM THIS DUE TO TOPOGRAPHY. EXTENDED DISCUSSION... MAINLY VFR INTO SATURDAY BEFORE NEXT FRONT AND UPPER DISTURBANCE ARRIVE SAT NIGHT-SUN WHICH COULD BRING SUB VFR WEATHER TO THE AREA...MAINLY BCB/BLF/LWB. MONDAY WILL BE MAINLY VFR WITH SOUTHWEST FLOW IN PLACE THOUGH WARM FRONT MAY BRING SOME MVFR CIGS AND POSSIBLE SHOWERS TO THE MOUNTAINS. WE WILL BE IN THE WARM SECTOR BY TUESDAY WITH ISOLATED TO SCATTERED SHOWERS OR THUNDERSTORMS EXPECTED. SOME MVFR POSSIBLE WITH THOSE OTHERWISE VFR. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...MBS/WP NEAR TERM...JR/KK SHORT TERM...MBS LONG TERM...MBS AVIATION...JR/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
132 PM EDT FRI MAY 6 2016 .SYNOPSIS... UPPER LOW MOVES FROM THE NC/VA COAST THIS MORNING NORTH TO PA/NJ BY SATURDAY MORNING. A COLD FRONT MOVES ACROSS THE AREA SATURDAY NIGHT INTO SUNDAY...STALLING ACROSS THE CAROLINAS MONDAY THEN MOVING NORTH AS A WARM FRONT BY TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 916 AM EDT FRIDAY... THE UPPER LOW WILL CONTINUE TO LIFT NORTHEAST TODAY AND REACH THE JERSEY SHORE ON SATURDAY MORNING. MODIFIED TEMPERATURES WITH LATEST OBS AND LEANED LATE MORNING INTO THE AFTERNOON TOWARDS THE LAV GUIDANCE. HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE UPPER 40S IN THE MOUNTAINS TO THE LOWER 60S IN THE PIEDMONT. DECREASED POPS FOR THIS MORNING WITH MORNING RADAR TRENDS AND SHAPED LATE MORNING AND EARLY AFTERNOON POPS TOWARDS RNK WRFARW SOLUTION. HAVE A GOOD DAY ! AS OF 730 AM EDT FRIDAY... LOOKING AT MAINLY HIGHER POPS IN THE EAST THIS MORNING WITH ISOLATED TO SCATTERED COVERAGE AT BEST WEST OF THE BLUE RIDGE. SYSTEM OVER EASTERN VIRGINIA/NORTH CAROLINA SHOULD SHIFT NORTHWARD TOWARD THE MID-ATLANTIC COAST OF MARYLAND AND NEW JERSEY THIS AFTERNOON. NO MAJOR CHANGES WITH THIS UPDATE. PREVIOUS MORNING DISCUSSION... UPPER LOW OVER EASTERN NORTH CAROLINA EARLY THIS MORNING WITH SFC LOW EAST OF THE TIDEWATER OF VA WILL KEEP AN AXIS OF STEADIER SHOWERS ACROSS THE PIEDMONT THIS MORNING INTO EARLY AFTERNOON WITH MORE ISOLATED TO SCATTERED COVERAGE FURTHER WEST. ANOTHER SHORTWAVE/VORT ROUNDING THE WEST SIDE OF THE UPPER LOW COMBINED WITH NW FLOW IN THE LOW LVLS SHOULD ENHANCE SOME SHOWERS ACROSS THE WV MTNS AS WELL...WITH THE LOWER THREAT OF SHOWERS ACROSS THE NC FOOTHILLS. RAINFALL AMOUNTS PER MODELS/WPC SUGGEST ANOTHER ONE QUARTER TO ONE HALF INCH IN THE EAST...WITH LOCALLY HIGHER AMOUNTS IF DEEPER CONVECTION CAN GET GOING...WHILE THE WEST WILL SEE ANOTHER QUARTER INCH OR LESS...WITH AGAIN HIGHER AMOUNTS MORE OVER SE WV LATER TODAY. AS FAR AS FLOOD CONCERNS GO...IT IS NOT ENOUGH TO WARRANT A WATCH...BUT GIVEN RAINFALL IN THE LOWER DAN RIVER BASIN...THE DAN AT SOUTH BOSTON WILL REACH MINOR FLOOD STAGE LATER BY DAWN TODAY...THEN DROP BELOW FLOOD STAGE TONIGHT. FLOOD WARNING ALREADY ISSUED FOR THIS AREA. WILL HAVE TO MONITOR RANDOLPH ON THE ROANOKE RIVER AND A FEW SURROUNDING STREAMS AND RIVERS THRU THE DAY. AS THE LOW OFF THE COAST AND UPPER LOW MOVE NORTHWARD MODELS ARE INDICATING SHARPER PRESSURE GRADIENT SITUATED OVER THE MOUNTAINS THIS AFTERNOON. WINDS WILL BE GUSTY BUT NOTHING OVER 35 MPH SHOULD OCCUR. WITH THE COOLER TEMPS ESPECIALLY IN THE HIGHER RIDGES...THE WINDS WILL ADD A NIP IN THE AIR. SPEAKING OF WHICH WILL SEE THE COLDER POCKET OF AIR MOVE EAST...SO ANY SNOW ACROSS THE NC HIGH COUNTRY INTO FAR SW VA SHOULD BE GONE BY MID MORNING. SOME SUNSHINE COULD WORK INTO THE NC/VA FOOTHILLS BY MID AFTERNOON. HIGH TEMPS WILL RANGE FROM THE UPPER 40S TO LOWER 50S ACROSS THE HIGHER ELEVATIONS OF THE WEST...WITH MID TO UPPER 50S ELSEWHERE WEST OF THE BLUE RIDGE...TO LOWER TO MID 60S EAST. TONIGHT...THE UPPER LOW WILL BE OVER ERN PA/NJ. SHOULD BECOME DRIER AS WE HEAD THROUGH THE OVERNIGHT...WITH SKIES CLEARING IN THE SOUTH AND WEST. SOME FOG MAY BECOME AN ISSUE LATE TONIGHT GIVEN THE WET GROUND...THOUGH WINDS MAY STAY UP JUST ENOUGH TO PREVENT A WIDESPREAD EVENT. LOWS WILL BE CLOSE TO NORMAL WITH LOWER TO MID 40S WEST...TO MID TO UPPER 40S EAST. && .SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/... AS OF 220 AM EDT FRIDAY... THE SLOW MOVING UPPER LOW THAT HAS BROUGHT PLENTY OF COOL AND WET WEATHER TO OUR REGION WILL FINALLY DEPART THE REGION ON SATURDAY. ANOTHER TROUGH/LOW MOVING THROUGH SOUTH CENTRAL CANADA WILL BE THE KICKER THAT GETS THE CLOSED LOW MOVING. THE BASE OF THE TROUGH AXIS OF THIS CANADIAN SYSTEM WILL SWING THROUGH OUR REGION BY SATURDAY EVENING. SHOWERS WILL STILL BE IN OUR FORECAST THIS WEEKEND. AFTER A SMALL BREAK IN THE ACTIVITY SATURDAY MORNING...ISOLATED TO SCATTERED SHOWERS WILL RETURN TO WESTERN PARTS OF THE AREA SATURDAY AFTERNOON IN ASSOCIATION WITH THE APPROACH OF THE TROUGH AXIS OF THE CANADIAN SYSTEM. ISOLATED THUNDER CANNOT BE RULED OUT IN THE FAR WEST. LIMITED...IF ANY...PRECIPITATION IS EXPECTED EAST OF THE CREST OF THE BLUE RIDGE. COVERAGE WILL INCREASE SATURDAY NIGHT AS THE UPPER TROUGH AXIS CROSSES THE REGION. EXPECT THE GREATEST COVERAGE ACROSS SOUTHEAST WEST VIRGINIA. AN ASSOCIATED SURFACE BOUNDARY IS PROGGED TO STALL OVER THE REGION IN THE WAKE OF THE PASSAGE OF THE UPPER TROUGH. THIS FEATURE IS EXPECTED TO ACT AS A FOCUS FOR ADDITIONAL ISOLATED TO SCATTERED COVERAGE OF SHOWERS HEADING INTO SUNDAY...WITH THE BEST COVERAGE ACROSS THE SOUTHWEST PORTION OF THE FORECAST AREA. SUNDAY NIGHT INTO MONDAY...WHAT REMAINS OF THE STALLED FRONTAL BOUNDARY WILL SLOWLY HEAD NORTH THROUGH THE REGION IN RESPONSE TO A DEEPENING UPPER TROUGH IN THE CENTRAL PORTION OF THE COUNTRY. SOUTHWEST FLOW AHEAD OF THIS FEATURE WILL START TO TAP GULF OF MEXICO MOISTURE AND ADVECT IN OUR WAY. ISOLATED TO SCATTERED SHOWERS WILL REMAIN IN OUR FORECAST...WITH THE BEST COVERAGE ACROSS THE NORTHERN AND WESTERN SECTIONS OF THE FORECAST REGION. TEMPERATURES DURING THIS PORTION OF THE FORECAST WILL TREND SLIGHTLY MILDER AND BE WITHIN A FEW DEGREES EITHER SIDE OF NORMAL FOR THIS TIME OF THE YEAR. && .LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 345 PM EDT THURSDAY... THE FRONTAL BOUNDARY WILL LIFT NORTH AS A WARM FRONT TUESDAY. MOISTURE CONVERGENCE ALONG THIS FRONT WILL RESULT IN A RISK FOR SHOWERS AND PERHAPS A FEW THUNDERSTORMS DURING THE PERIOD. ON WEDNESDAY...OUR AREA WILL BE IN THE WARM SECTOR WITH A WAVY WARM FRONT TO THE NORTH AND A COLD FRONT TO OUR WEST IN THE OHIO VALLEY. ON WEDNESDAY NIGHT INTO THURSDAY...THE LOW PRESSURE WILL LIFT NORTH INTO THE GREAT LAKES AND ASSOCIATED COLD FRONT WILL MOVE EAST INTO OUR REGION. THERE IS ENOUGH INSTABILITY TO MENTION GOOD CHANCE OF THUNDERSTORMS FOR THE NORTHWEST ON WEDNESDAY. HOWEVER...THE GREATEST INSTABILITY AS SEEN IN THE LIS IS TO OUR WEST AND SOUTHEAST. THE UNSETTLED WEATHER WILL CONTINUE ON THURSDAY...AS ANOTHER CLOSED LOW DROPS INTO THE UPPER MIDWEST AND GREAT LAKES REGIONS AND SHORTWAVES ROTATE AROUND THE BASE OF THE LOW. TEMPERATURES WILL MODERATE INTO MIDWEEK. THEN...BEHIND THE COLD FRONT...A COOL DOWN IS POSSIBLE FOR THE END OF THE WEEK. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... AS OF 130 PM EDT FRIDAY... THE UPPER LEVEL LOW THAT CREATED POOR FLIGHT CONDITIONS FOR MUCH OF THE PAST FEW DAYS IS FINALLY EXITING THE REGION TO THE EAST. SHOWERY CONDITIONS WILL BEGIN TO FORM UP IN THE REGION THIS AFTERNOON AT PEAK HEATING. BASED ON HRRR GUIDANCE...ROA/LYH/DAN WILL SEE SOME OF THIS ACTIVITY IN THE AFTERNOON INTO THE EVENING HOWEVER CONDITIONS LOOK TO REMAIN PRIMARILY VFR. OTHER LOCATIONS...CURRENTLY FORECAST FOR VICINITY SHOWERS DUE TO LOWER CONFIDENCE. FOG WAS CONSIDERED FOR THE OVERNIGHT HOURS BUT ENOUGH MIXING SHOULD OCCUR TO ELIMINATE THAT THREAT. LYH AND DAN APPEAR TO BE AT MOST THREAT BUT WAS LEFT OUT FOR NOW DUE TO LOW CONFIDENCE. WINDS ARE CURRENTLY A BIT GUSTY AND PRIMARILY FROM THE NORTHWEST FOR MUCH OF THE REGION. THESE SHOULD CALM DOWN WITH SUNSET BUT SHOULD BEGIN AGAIN AROUND SUNRISE. LYH SHOULD BE SPARED FROM THIS DUE TO TOPOGRAPHY. EXTENDED DISCUSSION... MAINLY VFR INTO SATURDAY BEFORE NEXT FRONT AND UPPER DISTURBANCE ARRIVE SAT NIGHT-SUN WHICH COULD BRING SUB VFR WEATHER TO THE AREA...MAINLY BCB/BLF/LWB. MONDAY WILL BE MAINLY VFR WITH SOUTHWEST FLOW IN PLACE THOUGH WARM FRONT MAY BRING SOME MVFR CIGS AND POSSIBLE SHOWERS TO THE MOUNTAINS. WE WILL BE IN THE WARM SECTOR BY TUESDAY WITH ISOLATED TO SCATTERED SHOWERS OR THUNDERSTORMS EXPECTED. SOME MVFR POSSIBLE WITH THOSE OTHERWISE VFR. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...MBS/WP NEAR TERM...KK/WP SHORT TERM...DS LONG TERM...KK AVIATION...JR/WP
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
340 PM CDT FRI MAY 6 2016 .TONIGHT AND SATURDAY... FORECAST CONFIDENCE MEDIUM. THE RIDGE OF HIGH PRESSURE WITH ALL THE WARM AIR OVER THE UPPER MIDWEST LEANED INTO WISCONSIN TODAY. A COLD FRONT WILL SLIDE DOWN THROUGH WI OVERNIGHT AND CLEAR SOUTHEAST WI BY MID SATURDAY MORNING. GUSTY NORTH TO NORTHEAST WINDS WILL ACCOMPANY THE FRONT IN SOUTHERN WI LATE TONIGHT. THERE ARE TWO CHANCES FOR SHOWERS AND MAYBE SOME ELEVATED THUNDERSTORMS TONIGHT. THE HRRR MODEL... AND TO A LESSER EXTENT OTHER MESO MODELS... IS MORE ROBUST ON THE IDEA OF SHOWERS/CONVECTION WELL AHEAD OF THE FRONT AND THE NAM/GFS/ECMWF FOCUS IT ALONG THE FRONT. KEPT CHANCE OF SHOWERS AND THUNDERSTORMS FOR THE MAJORITY OF THE NIGHT INTO EARLY SATURDAY TO ACCOUNT FOR THESE SCENARIOS. THE HRRR SOLUTION SHOWS SHOWERS/STORMS IN SOUTHERN WI BETWEEN 05Z AND 08Z. IT IS PICKING UP ON A WEAK MID LEVEL SHORTWAVE AND THETA-E ADVECTION AND THE FOCUS OF THE 850MB LOW LEVEL JET. THE NAM IS SHOWING OVER 1000 J/KG OF ELEVATED INSTABILITY WHILE THE GFS HAS MUCH LOWER VALUES. THERE IS NOT A LOT OF MOISTURE AVAILABLE SO NOT EXPECTING ANY WIDESPREAD SHOWERS/STORMS. IF THE SHOWERS END UP DEVELOPING CLOSER TO THE COLD FRONT... LIKE ALONG AND BEHIND IT... THEY WOULD AFFECT SOUTHERN WI BETWEEN 11Z AND 17Z SATURDAY MORNING. THESE WOULD BE ASSOCIATED WITH SURFACE CONVERGENCE ALONG THE FRONT AND STRONG MID LEVEL VORTICITY ADVECTION. MODELS ARE SHOWING VERY LITTLE ELEVATED INSTABILITY BY THIS TIME... SO THE CHANCE FOR THUNDERSTORMS IS GREATLY REDUCED. CLOUDS MAY LINGER FOR A FEW HOURS IN THE WAKE OF THE COLD FRONT. THEN DRY AIR WILL WORK ITS WAY IN AND LEAD TO SUNSHINE BY LATE AFTERNOON. TEMPERATURES ARE EXPECTED TO REACH THE UPPER 60S INLAND BUT ONLY THE UPPER 50S NEAR THE LAKE DUE TO STEADY NORTHEAST WINDS. .SATURDAY NIGHT THROUGH SUNDAY NIGHT...FORECAST CONFIDENCE MEDIUM MODELS SHOWING A MODERATE TO STRONG FRONTOGENETIC RESPONSE IN THE 700 TO 500 MB LAYER THAT CROSSES SOUTHERN WISCONSIN SATURDAY EVENING WITH THE 700 MB COLD FRONT AS A SHORT WAVE SWEEPS ACROSS NE WISCONSIN LATE SATURDAY AFTERNOON AND EVENING. NO PRECIPITATION IS EXPECTED AS MEAGER MOISTURE ON FORECAST SOUNDINGS AND CROSS SECTIONS WITH SURFACE HIGH PRESSURE BUILDING IN MEANS NO MORE THAN SOME MID LEVEL CLOUDS WITH THIS FRONT...THAT STALLS OVER THE SOUTH OVERNIGHT. DRY WEATHER EXPECTED TO CONTINUE THROUGH MOST OF SUNDAY NIGHT WITH SHORT WAVE RIDGING BETWEEN LARGE EASTERN CANADIAN VORTEX AND CLOSED 500 MB LOW...AND ASSOCIATED SURFACE LOW...MOVING OUT INTO THE CENTRAL PLAINS BY MONDAY MORNING. SOME MODELS BRING QPF WITH 700 MB OMEGA AND MID-LEVEL MOISTURE PUSHING IN BEFORE 12Z IN THE FAR SOUTH/SOUTHWEST SECTIONS OF THE CWA...BUT ISENTROPIC FORECASTS SHOW LOW LEVEL MOISTURE AND BETTER ISENTROPIC ADIABATIC OMEGA REMAIN SW OF CWA THROUGH 12Z MONDAY SO WILL KEEP POPS IN THE SLIGHT CHANCE/LOW CHANCE CATEGORIES FOR THE FAR SOUTH AND SOUTHWEST. NO REAL STRONG PUSH OF COLD AIR INTO SOUTHERN WISCONSIN BUT EXPECTED MODERATE NOCTURNAL INVERSION DEVELOPING WITH LIGHT WINDS AND CLEAR SKIES WILL PRODUCE LOWS IN THE UPPER 30S TO LOW 40S SATURDAY NIGHT. DEEP MIXING WILL EASILY ALLOW SUNDAY HIGH TEMPERATURES TO REACH THE UPPER 60S TO LOW 70S. TEMPERATURES WILL EVEN GET INTO THE LOW TO MID 60S IN THE LAKESIDE COUNTIES...BUT LIGHT WIND REGIME WITH SURFACE HIGH SLIDING ACROSS STATE WILL ALLOW A LAKE BREEZE TO DEVELOP MID- LATE AFTERNOON. .MONDAY AND MONDAY NIGHT...FORECAST CONFIDENCE MEDIUM PRECIPITATION CHANCES INCREASE WITH CONVERGENCE AND FRONTOGENETIC RESPONSE TO 850-700 MB WARM AIR/MOISTURE ADVECTION...ENHANCED BY DIFFERENTIAL CVA WITH SHORT WAVE APPROACHING SOUTHERN WISCONSIN MONDAY EVENING. THOUGH SURFACE BASED INSTABILITY WILL BE LOW AS SURFACE WARM FRONT GETS UP TO THE IL/WI BORDER MONDAY EVENING THEN STALLS...ELEVATED CAPE VALUES MONDAY AFTERNOON AND NIGHT CLIMB TO 400-600J/KG SO DO EXPECT THUNDERSTORMS. PRECIPITATION AND EAST WINDS LEAD TO CUTTING MONDAY HIGH TEMPERATURES FROM PREVIOUS FORECAST. .LONG TERM...TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM PERIODIC SHOWERS...WITH A FEW THUNDERSTORMS EARLY IN THE EXTENDED ...ARE EXPECTED WITH THE ACTIVE UPPER AIR PATTERN. MODELS SIMILAR WITH FEATURES BUT DIFFER WITH TIMING AND POSITION. CANADIAN GEM AND ECMWF HINT AT A BREAK IN THE PCPN CHANCES FOR A TIME ON WEDNESDAY...WHILE THE GFS IS RAIN-FREE OVER SRN WI ON THURSDAY. WILL HAVE TO KEEP CHANCE/SLIGHT CHANCE POPS IN EVERY PERIOD THROUGH THERE WILL BE SOME BREAKS IN THE PRECIPITATION. THE CLOUDS AND PERIODIC SHOWERS WILL KEEP TEMPERATURES AT OR SLIGHTLY BELOW NORMAL. && .AVIATION/00Z TAFS/... VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD... ALTHOUGH BRIEF LOWER CATEGORIES WILL BE OVERNIGHT TONIGHT WITH ANY THUNDERSTORM. A COLD FRONT WILL SLIDE DOWN THROUGH SOUTHERN WI LATE TONIGHT INTO MID SATURDAY MORNING. THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS WELL AHEAD OF THE FRONT... AROUND 1 TO 3 AM. THERE IS ANOTHER CHANCE FOR SHOWERS AND LESS OF A CHANCE FOR THUNDER ALONG THE FRONT EARLY SATURDAY MORNING. EXPECT GUSTY NORTH TO NORTHEAST WINDS IN THE WAKE OF THE FRONT SATURDAY MORNING... BUT THEY WILL DIMINISH THROUGH THE AFTERNOON. CEILINGS ASSOCIATED WITH THE FRONT ARE EXPECTED TO REMAIN VFR. && .MARINE... GUSTY NORTH TO NORTHEAST WINDS ARE EXPECTED IN THE WAKE OF A COLD FRONT EARLY SATURDAY MORNING. WAVES WILL APPROACH 5 FEET FROM MILWAUKEE AND SOUTH. A SMALL CRAFT ADVISORY IS IN EFFECT. WINDS AND WAVES WILL DIMINISH SATURDAY AFTERNOON. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ TONIGHT/SATURDAY AND AVIATION/MARINE...MRC SATURDAY NIGHT THROUGH FRIDAY...REM