Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 040941 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 441 AM EST THU FEB 4 2016 .SYNOPSIS... A COLD FRONT CROSSES THE AREA THIS MORNING...THEN STALLS NEAR THE COAST THIS AFTERNOON. LOW PRESSURE DEVELOPS ALONG THE FRONT TONIGHT...THEN TRACKS NORTHEAST AWAY FROM THE AREA FRIDAY. HIGH PRESSURE BUILDS IN FROM THE WEST LATE FRIDAY INTO SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST SFC ANALYSIS SHOWS 996 MB LO PRES CENTERED OVER SE CANADA WITH ITS ATTENDANT COLD FRONT STRETCHING DOWN THRU WRN VA/WRN NC. THE FRONT WILL CONTINUE TO SLIDE E...EVENTUALLY CROSSING THE FA LATER THIS MORN. LGT TO MODERATE RAIN CONTINUES EARLY THIS MORN ACROSS SE VA/NE NC...WITH THE REMAINDER OF THE AREA DRY WITH A CLOUDY SKY AND SLY WINDS KEEPING TEMPS IN THE LWR 60S MOST AREAS. EXPECT HI TEMPS TDA TO OCCUR THIS MORN IN MOST SPOTS...WITH TEMPS THEN SLOWLY FALLING/REMAINING STEADY THRU THE DAY AS THE FRONT PUSHES THRU THE AREA AND WEAK CAA ENSUES. AS FOR PCPN...PERIODS OF ANAFRONTAL RAIN WILL CONTINUE ESPECIALLY OVER SE AREAS DUE TO A STEADY GOM MOISTURE STREAM AND THE REGION BEING IN THE RIGHT ENTRANCE REGION OF AN UPR-LEVEL JET STREAK. AN ADDITIONAL INCH OF RAIN IS PSBL OVER NE NC DURING THE DAYTIME PERIOD. TRICKY PART OF THE FORECAST IS HOW FAR TO THE NW THE RAIN REACHES THIS AFTN...FOR NOW WILL GO WITH 70% POPS FOR AKQ DROPPING TO 50% FOR RIC THEN 20% FOR LKU. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... INTERESTING FCST TNGT AS DEVELOPING LO PRES TRACKS NE ALONG THE OFFSHORE FRONTAL BOUNDARY. CAA ALLOWS TEMPS AND CRITICAL THICKNESSES TO FALL BEFORE THE PCPN ENDS. HOWEVER...SFC TEMPS PROGGED TO STAY JUST ABOVE FREEZING. THIS PRESENTS PCPN TYPE ISSUES WITH RAIN BECOMING MIXED WITH OR CHANGING TO WET SNOW BEFORE ENDING. DATA SUGGESTS LAGGING VORTICITY PROVIDES ENUF LIFT FOR A LIGHT ACCUMULATION. GIVEN HOW WET THE GROUND WILL BE AND WITH TEMPS ABOVE FREEZING...ANY SNOW WOULD HAVE TO COME DOWN RATHER HARD TO STICK. THUS...HAVE INDICATED A RAIN/SNOW MIX CHANGING TO SNOW BY 12Z FRI WITH ACCUMULATIONS UP TO AROUND AN INCH FOR N/NE PORTIONS OF THE FA. UP TO A COUPLE INCHES CANNOT BE RULED OUT. LOWS IN THE L-M30S. LINGERING POPS FRI MORNING (SNOW NRN AREAS...MAINLY RAIN TO THE S) WILL PUSH OFFSHORE AS HIGH PRES BUILDS EAST AND INTO THE AREA. TSCTNS SHOW DRYING SO EXPECT DECREASING CLOUDINESS WEST TO EAST FRI AFTN. HIGHS IN THE M40S. MOSTLY CLR FRI NIGHT. LOWS M20S NW TO L30S SE. PARTLY SUNNY SAT. HIGHS 45-50. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... THE LONG TERM PERIOD FEATURES A COUPLE OF INTENSIFYING LOW PRESSURE SYSTEMS OFF THE SE COAST AND MOVING NORTHEAST. BOTH OF THESE THREATEN TO BRING PCPN TO THE AREA. THE GFS AND EURO WERE TRENDING TOWARD AN OFFSHORE SOLUTION. THIS WOULD SUGGEST THAT PCPN AMOUNTS MAY NOT BE HEAVY. SINCE THE EVENTS ARE STILL CLOSE TO A WEEK OUT...ESPECIALLY THE SECOND ONE...DETAILS ARE STILL UNCERTAIN. FOR NOW KEPT POPS NO HIGHER THAN 40 PERCENT. RELIED HEAVILY ON BLENDED GUIDANCE WITH THE FORECAST. THE FIRST SYSTEM MOVES OFF THE SOUTHEAST COAST SATURDAY NIGHT AND BRINGS A CHC FOR RAIN OVER SE VA/NE NC SUNDAY. HIGH PRESSURE BUILDS OVER EASTERN CANADA AND SOUTH INTO THE NORTHEAST CONUS BEHIND THE FIRST BRINGING SOME COOLING. AN UPPER LEVEL TROUGH DEEPENS MONDAY THROUGH TUESDAY OVER THE GREAT LAKES AND OHIO VALLEY AS THE SECOND LOW PRESSURE SYSTEM DEVELOPS OFF THE COAST. PCPN IS FORECAST TO DEVELOP MONDAY NIGHT AND CONTINUE THROUGH TUESDAY BEFORE ENDING FROM SW TO NE TUESDAY NIGHT. CURRENTLY HAVE A MIXTURE OF RAIN AND SNOW OVER MOST OF THE AREA WITH MAINLY RAIN AT THE COAST. THE UPPER LEVEL SYSTEM MAY CONTRIBUTE TO SOME OF THE PCPN INLAND. ARCTIC AIR WILL REMAIN WELL TO THE NORTH KEEPING DAYTIME TEMPERATURES ABOVE FREEZING. LOW PRESSURE MOVES OFF TO THE EAST WITH DRY AND COOLER WEATHER FOR WEDNESDAY. A GRADUAL COOLING TREND IS EXPECTED THROUGH THE PERIOD. HIGHS IN THE UPR 40S TO AROUND 50 SUNDAY COOL TO AROUND 40 BY WEDNESDAY. LOW TEMPERATURES FROM 30 TO 35 SUNDAY THROUGH TUESDAY BECOME MID 20S TO LOWER 30S WEDNESDAY MORNING. && .AVIATION /10Z THURSDAY THROUGH MONDAY/... MAINLY IFR/LIFR CONDITIONS ACROSS TERMINALS EARLY THIS MORNING JUST AHEAD OF SFC COLD FRONT, WHICH WILL CROSS THE AREA THROUGH MID- MORNING, EVENTUALLY PUSHING OFFSHORE LATE THIS AFTN. EXPECT INCREMENTAL IMPROVEMENT BACK TO MVFR THEN VFR AT RIC/SBY FROM MID MORNING TO ABOUT 16Z. HOWEVER...EXPECT SE COASTAL TERMINALS (PHF/ORF/ECG) WILL REMAIN DOWN IN THE IFR/LOW END MVFR RANGE THROUGH MUCH OF THE TAF PERIOD. MODELS SHOW THE FRONT STALLING IN THE VICINITY OF THE COAST TNGT, WITH A CONTINUED STREAM OF MOISTURE LIFTING NE ALONG THE CAROLINA COAST TOWARD THE LOCAL AREA. PERIODS OF RAIN/BR WL CONTINUE THIS AFTN AND EARLY TNGT. OUTLOOK...CONDITIONS DETERIORATE ONCE AGAIN THU NGT/EARLY FRIDAY AS AN UPPER DISTURBANCE CROSSES THE AREA. IFR CIGS AND DIMINISHED VSBY IS EXPECTED W/A PERIOD OF RAIN/SNOW SHOWERS LKLY (MAINLY RA AT ECG) LATE THU NGT/EARLY FRIDAY. VFR CONDITIONS RETURN BY FRIDAY AFTN THROUGH THE WEEKEND WITH COLD HIGH PRESSURE BUILDING OVERHEAD. && .MARINE... SFC COLD FRONT CONTINUES TO APPROACH THE WATERS THIS MORNING, AND SHOULD CROSS THE WATERS FROM DAYBREAK THROUGH MIDDAY...BEFORE PUSHING JUST OFFSHORE THROUGH THIS EVENING. WINDS HAVE BRIEFLY DIMINISHED SUB-SCA IN W-SW FLOW JUST AHEAD OF THE FRONT. EXPECT THAT WINDS WILL RAMP UPWARD AGAIN IN POST-FRONTAL N-NW SURGE, PERHAPS DROPPING OFF SLIGHTLY IN THE MID-LATE AFTN. HOWEVER, EXPECT WINDS TO INCREASE AGAIN AFTER MIDNIGHT TONIGHT AS FRONT STALLS JUST OFFSHORE AS SFC LOW PRESSURE DEVELOPS AS IT PUSHES FARTHER OFFSHORE INTO FRIDAY MORNING. ALTHOUGH PRECIPITATION REMAINS ANCHORED ALONG THE COAST DURING THIS TIME PERIOD...A STRONGER N-NW SURGE IS ANTICIPATED THU NIGHT INTO FRI AS HIGH PRESSURE FINALLY SLIDES ACROSS SRN ONTARIO DOWN ACROSS THE TN VALLEY. THE PRESSURE GRADIENT BTWN THE DEVELOPING LOW AND INCOMING HIGH WILL RESULT IN THE STRONG N-NW SURGE WITH GUSTS AVERAGING 25-30 KT ALL WATERS. HAVE GONE WITH A GALE WARNING OVER THE CENTRAL AND SOUTHERN COASTAL ZONES FOR TONIGHT THROUGH MIDDAY FRIDAY. GUSTS TO GALE FORCE ARE EXPECTED DURING THIS TIMEFRAME...WITH THE BEST CHCS BETWEEN 09-17Z (4A- 12P). NOT CONFIDENT ENOUGH IN PROLONGED PERIOD OF GALE FORCE GUSTS IN THE LOWER BAY OR SOUND JUST YET...AND THUS HAVE MAINTAINED STRONG SCA IN THESE AREAS. HOWEVER, A BRIEF PERIOD OF GALES POSSIBLE AROUND SUNRISE FRIDAY MORNING. SCA NOW IN PLACE FOR BAY, LOWER JAMES AND NRN COASTAL ZONES THROUGH FRIDAY AFTN, AND FOR THE REMAINDER OF THE RIVERS FOR TONIGHT THROUGH FRIDAY. THERE WILL BE PERIODIC LULLS IN WIND SPEEDS AT TIMES THIS MORNING AND AGAIN THIS AFTN BUT NOT LONG ENOUGH TO NECESSITATE BREAK IN SCA CONDITIONS/HEADLINES. SEAS AVERAGE 4-6FT TDA/TNGT... BUILDING TO 6-9FT SRN COASTAL WATERS LATE TONIGHT/FRI. WAVES ON CHES BAY AVERAGE 3-4FT...BUILDING TO 4-6FT LATE THU NIGHT/FRI MORNING. WINDS FINALLY BEGIN TO DROP OFF FRI NIGHT AND EARLY ON SAT AS COOL HIGH PRESSURE FINALLY SLIDES OVERHEAD AND THEN OFFSHORE BY SAT NIGHT. WINDS/SEAS/WAVES SUBSIDE BELOW SCA CONDITIONS PRIMARILY FOR SAT ONLY BEFORE THE NEXT LOW PRESSURE SYSTEM MOVES UP THE SE COAST. SPATIAL/TEMPORAL DIFFERENCES REMAIN WITH THE TRACK OF THIS SYSTEM, BUT SCA TO GALE FORCE IMPACTS APPEAR POSSIBLE BY LATER SUN MORNING INTO MONDAY. GFS/WAVEWATCH A BIT LESS AGGRESSIVE WITH LATEST 00Z/4FEB RUN...BUT HAVE CONTINUED WITH TRENDING SEAS BACK UPWARD QUICKLY ON SUNDAY/SUN NIGHT. && .HYDROLOGY... FLOOD WARNING CONTINUES FOR RICHMOND/WESTHAM...AND A NEW FLOOD WARNING HAS BEEN ADDED FOR THE MEHERRIN AT LAWRENCEVILLE. THE RUNOFF FROM THE EXPECTED RAINFALL OVER THE NEXT 24-36 HRS WILL LIKELY PUSH RIVER LEVELS AT A FEW SITES TO NEAR OR JUST ABOVE FLOOD STAGE GIVEN MOST RIVERS ARE PRESENTLY RUNNING AT THREE QUARTERS BANKFULL. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EST FRIDAY FOR ANZ635>637. SMALL CRAFT ADVISORY UNTIL 6 PM EST FRIDAY FOR ANZ630>634-638- 650-652. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ654- 656-658. GALE WARNING FROM 6 PM THIS EVENING TO NOON EST FRIDAY FOR ANZ654-656-658. && $$ SYNOPSIS...MAS NEAR TERM...MAS SHORT TERM...MAS/MPR LONG TERM...LSA AVIATION...MAM/JEF MARINE...MAM HYDROLOGY...

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