Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 242245 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 545 PM EST SAT JAN 24 2015 .SYNOPSIS... LOW PRESSURE WILL CONTINUE TRACKING WELL OFF TO THE NORTHEAST OF THE REGION THIS EVENING AS HIGH PRESSURE BEGINS TO BUILD IN FROM THE SOUTHWEST. THIS HIGH WILL SHIFT OFF THE SOUTHEAST COAST SUNDAY AFTERNOON...AS ANOTHER LOW PRESSURE SYSTEM APPROACHES FROM THE NORTHWEST. THIS LOW WILL CROSS THE AREA SUNDAY NIGHT INTO MONDAY..AND WILL RAPIDLY INTENSIFY OFF THE MID ATLANTIC AND NEW ENGLAND COASTS LATE MONDAY THROUGH TUESDAY. && .NEAR TERM /THROUGH SUNDAY/... LATE MORNING ANALYSIS DEPICTS ~980 MB SFC LOW PRESSURE NOW WELL OFF TO OUR NE ALONG THE NEW ENGLAND COAST. LAGGING UPPER TROUGH/SHORTWAVE ENERGY IS NOW REACHING THE COAST...WITH SKIES CLEARING ALONG/WEST OF THE I-95 CORRIDOR AND PRECIP NOW BECOMING CONFINED TO ERN 1/2 OF THE CWA. HAVE SEEN SOME ENHANCED HEAVIER SHOWERS...BUT DEW PTS HAVE BEEN TOO HIGH FOR ANY MIX THUS FAR. THINKING NOW IS THAT BEST CHC FOR SEEING A BRIEF PERIOD WHERE PCPN COULD TURN TO SNOW OR RAIN/SNOW/SLEET MIX WILL BE CONFINED TO THE ERN SHORE THROUGH THE NEXT FEW HRS. OTHERWISE...PRECIP ENDING WITH SKIES BECOMING PARTLY CLOUDY TO MOSTLY CLEAR UNDER WLY FLOW. NOT A LOT OF COLD AIR TO OUR W/NW...SO LOWS OVERNIGHT WILL GENLY BE FROM THE UPPER 20S TO THE LOWER 30S. ON SUN...CLIPPER SYSTEM CURRENTLY TAKING SHAPE ACRS THE UPPER MIDWEST PROGGED TO DIVE ESE INTO THE MID MS VALLEY BY 12Z INTO THE LWR OH VALLEY BY 00Z/MON. THIS AS SFC HIGH SHIFTS OFF THE SE COAST. SHOULD BE A MILD DAY WITH PARTLY TO MOSTLY SUNNY SKIES...HIGHS INTO THE MID 50S SOUTH TO THE UPPER 40S NORTH. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... ACTIVE PATTERN IN THE SHORT TERM...GENERAL PATTERN IS AGREED UPON BY THE LATEST 12Z SUITE OF MODELS...BUT WITH DIFFERENCES IN PLACEMENT OF THE EVENTUAL TRACK OF THE SFC LOW OFF THE COAST LATE MON-TUE LEADING TO SUBSTANTIAL DIFFERENCES IN SENSIBLE WX...MAINLY POTENTIAL SNOW AMOUNTS FOR THE REGION LATE MON-TUE. 12Z ECMWF IS BY FAR THE MOST AGGRESSIVE AT DEVELOPING A CUTOFF UPPER LOW IN THE VICINITY OF THE DELMARVA MON NIGHT/TUE...WHILE THE GFS AND NAM ARE WEAKER WITH THIS FEATURE. MAIN THEME FOR SUN NIGHT INTO MIDDAY MON IS A SLOWER ARRIVAL OF COLD AIR...THUS MOST OF THE CWA WILL SEE RAIN THROUGH MOST OF THE DAY MON...RATHER THAN SNOW. WILL CARRY HIGH CHC TO LIKELY POPS (HIGHER NORTH) AFTER MIDNIGHT THROUGH MON AM. LOWS IN THE UPPER 30S S TO THE LOWER 30S N. CONFIDENCE IN THE MON NIGHT TO TUE PERIOD IS BELOW AVG GIVEN THE MAJOR MODEL DISCREPANCIES...THE ECMWF FORECASTING A BLIZZARD FOR THE NRN MID ATLC REGION AND NE STATES...WHILE THE GFS/NAM WOULD SUGGEST OUR NE ZONES GET "BRUSHED" WITH LIGHT SNOW ACCUMULATIONS. HAVE GENLY SPLIT THE DIFFERENCE FOR NOW AND GONE CLOSE TO WPC FORECASTS. MOST OF THE CWA HAS A GOOD CHC FOR SEEING AT LEAST LIGHT SNOW ACCUMULATIONS MON NIGHT/TUE MORNING...WITH THE MOST UNCERTAINTY OVER THE ERN 1/3 OF THE CWA WHERE A SIGNIFICANT WINTER STORM IS POSSIBLE. WILL CARRY LIKELY POPS E TO HIGH CHC ELSEWHERE MON AFTN THROUGH MON NIGHT INTO TUE MORNING. HIGHS MON WERE RAISED INTO THE 45-50 F RANGE ACRS THE SOUTH...WITH UPPER 30S OVER THE FAR NORTH. TEMPS WILL LIKELY FALL LATER IN THE AFTN...WITH PTYPE BECOMING MAINLY SNOW FROM N TO S LATE MON AFTN INTO MON EVENING. LOWS MON NIGHT IN THE MID/UPPER 20S TO LOWER 30S WITH HIGHS TUE IN THE 30S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... LOW PRESSURE DEEPENS AND LIFTS AWAY FROM THE MID-ATLANTIC COAST TUES NIGHT AS THE DEEP/ANOMALOUS NRN STREAM TROUGH REMAINS OVER THE LOCAL AREA. THE TROUGH AXIS PROGGED TO PUSH OFFSHORE WEDS RESULTING IN NWLY FLOW ALOFT. DISTURBANCES IN THE NWLY FLOW ALOFT WILL TRAVERSE THE LOCAL AREA WEDS...BUT HIGH PRESSURE BUILDING IN AT THE SFC AND DRYING CONDITIONS ALOFT WILL KEEP THE FORECAST DRY. CAA WILL RESULT IN H85 TEMPS FALLING TO AROUND -6 TO -10C DURING THE DAY...YIELDING TEMPS IN THE MID-UPPER 30S. COLDER TEMPS OVER THE ERN SHORE...WITH HIGHS IN THE LOW 30S. UPPER/SFC HIGH PRESSURE BUILDS OVER THE REGION WEDS NIGHT AS THE NEXT SHORTWAVE AND ASSOCIATED SFC LOW APPROACH FROM THE WEST ON THURS. SFC LOW AND TRAILING COLD FRONT CROSS THE REGION THURS NIGHT-FRI MORNING. WHILE THE STRONGEST HEIGHT FALLS ARE EXPECTED TO CROSS THE REGION...BEST MOISTURE PROGGED TO BE ACROSS THE NE. WILL CARRY CHANCE POPS GENERALLY NORTH AND EAST OF RICHMOND THURS NIGHT AND SLIGHT CHANCE SOUTH AND WEST. THERMAL PROFILES...LOW TEMPS AND AIR MASS SUPPORT PREDOMINATELY RAIN ATTM...BUT RAIN/SNOW MIX IS POSSIBLE OVER THE NE ZONES. DRYING FRI AS HIGH PRESSURE BUILDS INTO THE REGION. THEREAFTER...MODELS COMPETING ON WHICH STREAM WINS THRU THE WEEKEND. GFS FAVORS A SRN STREAM SYSTEM WITH THE ECMWF FAVORING A NRN STREAM SYSTEM. TEMPS GENERALLY NEAR NORMAL THURS-FRI...DROPPING INTO THE UPPER 30S-LOW 40S SAT. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... RAIN WITH THE ACTUAL LOW PRESSURE HAS MOVED EAST AND OFFSHORE ERLY THIS AFTRN. UPR LVL SYSTM TO CROSS THE AREA NEXT 2-5 HRS WITH THE NEXT ROUND OF PCPN. CIGS ALRDY IFR BUT VSBYS HAVE IMPROVED PAST FEW HRS...MAINLY DUE TO THE CAA AND GUSTY WINDS BEHIND DEPARTING LOW. THUS...WENT WITH A 3 HR TEMPO GROUP FOR -RA & LWR VSBYS AS THE PCPN MOVES EAST ACROSS THE FA THIS AFTRN. APPEARS CAA MAY ALLOW FOR SOME SLEET & MAYBE WET SNOW FLAKES TO MIX IN AT SBY BEFORE ENDING ARND SUNSET. NW TO W WNDS AVG 10-15 WITH G20 KTS ALONG THE COAST. TSCTNS SHOW A QUICK DRYING OF THE COLUMN AFTR 00Z RESULTING IN CRG SKIES THRU THE EVENING. SO XPCT CINDITIONS TO IMPROVE TO VFR TONIGHT AND CONTINUE INTO SUNDAY AS HIGH PRS BUILDS INTO THE AREA. OUTLOOK: ANOTHER WEATHER SYSTEM WILL IMPACT THE AREA MONDAY INTO TUESDAY. THIS COULD AGAIN CAUSE SOME MVFR TO IFR CEILINGS ALONG WITH A CHANCE FOR SOME WINTRY PRECIPITATION...MOST LIKELY RAIN SHOWERS CHANGING TO SNOW SHOWERS MONDAY INTO TUESDAY. HIGH PRESSURE BUILDS OVER THE REGION FROM THE WEST FOR MID TO LATE WEEK...WITH VFR CONDITIONS EXPECTED FOR MUCH OF THE PERIOD. && .MARINE... LATEST WX ANALYSIS DEPICTS INTENSIFYING LOW PRESSURE OFF LONG ISLAND THIS AFTERNOON. FLOW OVER THE WATER GENERALLY NWLY 15-25 KT...WITH SOME GUSTS UP TO 30 KT OVER THE COASTAL WATERS. WAVES GENERALLY 2-4 FT AND SEAS 5-7 FT. SCA HEADLINES REMAIN IN EFFECT FOR THE BAY/SOUND/LOWER JAMES/COASTAL WATERS. NWLY WINDS OVER THE ERN VA RIVERS HAVE INCREASED SLIGHTLY THIS AFTERNOON TO AROUND 15 KT...BUT SCA CONDITIONS NOT ANTICIPATED. LOW-LEVEL CAA WANES THIS EVENING OVER THE BAY AS THE PRESSURE GRADIENT RELAXES...ALLOWING HEADLINES OVER THE BAY/SOUND/LOWER JAMES TO DROP OFF. STILL ANTICIPATE GUSTS OF 20 KT IN THE MOUTH OF THE BAY AND GUSTS TO 25 KT IN THE COASTAL WATERS...SO WILL MAINTAIN SCA HEADLINES. SEAS SUBSIDE THRU THE NIGHT...DROPPING BELOW 5 FT EARLY SUN MORNING. HIGH PRESSURE BUILDS OVER THE SE STATES SUN...EXTENDING NWD OVER THE WATERS. FLOW BECOMES SLY DURING THE AFTERNOON AOB 10KT. THE NEXT IN A SERIES OF CLIPPER SYSTEMS PROGGED TO CROSS THE WATERS MON. THE LOW IS THEN EXPECTED TO STRENGTHEN RAPIDLY AS IT LIFTS NWD ALONG THE COAST. MODELS HANDLING THE STRENGTH OF THE LOW DIFFERENTLY...WITH THE GFS AND ECMWF BEING DEEPER WITH THE SFC LOW AND STRONGER WITH THE WINDS. CERTAINTY IS FOR STRONG SCA CONDITIONS...WITH INCREASING CERTAINTY FOR LOW END GALE CONDITIONS...ESPECIALLY OVER THE COASTAL WATERS. ANOTHER WEAKER SYSTEM CROSSES THE WATERS TUES...REINFORCING THE COLD AIR OVER THE REGION. THE RESULT WILL BE AN EXTENDED PERIOD OF SCA CONDITIONS OVER THE WATERS. BEST CHANCE FOR GALES WILL BE MON NIGHT WITH SCA CONDITIONS PERSISTING THRU TUES NIGHT. SEAS MAY REMAIN ELEVATED AOA 5 FT THRU THE DAY WEDS. HIGH PRESSURE RETURNS LATE WEDS INTO WEDS NIGHT...IN ADVANCE OF THE NEXT SYSTEM SET TO CROSS THE WATERS THURS NIGHT. SCA CONDITIONS APPEAR POSSIBLE YET AGAIN. && .TIDES/COASTAL FLOODING... LOW PRESSURE IS FORECAST TO INTENSIFY RAPIDLY OFF THE MID-ATLANTIC COAST MONDAY NIGHT. THE RESULT WILL BE A PERIOD OF STRONG NLY WINDS OVER THE WATERS. TIDAL ANOMALIES ARE EXPECTED TO REACH 1 TO 1.5 FT...POSSIBLY HIGHER...DURING MONDAY NIGHT AND TUESDAY MORNINGS HIGH TIDE CYCLES. SEVERAL SITES IN THE LOWER BAY WILL REACH HIGHEST ASTRO TIDE WITH WATER LEVELS APPROACHING MINOR FLOODING THRESHOLDS AT SEWELLS POINT MONDAY NIGHT. MINOR FLOODING IS ALSO POSSIBLE AT OCEAN CITY INLET. HIGH TIDES ARE EXPECTED AGAIN TUES...BEFORE ANOMALIES DROP OFF LATE TUES INTO TUES NIGHT AS THE LOW LIFTS AWAY FROM THE REGION. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ634. SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ630>633-638. SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ650-652-654- 656-658. && $$ SYNOPSIS...LKB NEAR TERM...LKB SHORT TERM...LKB/TMG LONG TERM...SAM AVIATION...MPR MARINE...SAM TIDES/COASTAL FLOODING...SAM

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