Area Forecast Discussion
Issued by NWS Wakefield, VA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KAKQ 300051 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 851 PM EDT SUN MAR 29 2015 .SYNOPSIS... A WEAK COLD FRONT MOVES ACROSS THE AREA MONDAY MORNING. HIGH PRESSURE RETURNS MONDAY AFTERNOON AND NIGHT. LOW PRESSURE TRACKS ACROSS THE NORTHERN MID ATLANTIC TUESDAY WITH THE ASSOCIATED COLD FRONT DROPPING THROUGH THE REGION TUESDAY NIGHT. && .NEAR TERM /THROUGH MONDAY/... RIDGE AXIS MOVING OFFSHORE RESULTING IN A WIND SHIFT TO THE S-SW THIS EVENING. SKIES STILL SKC ERN HALF OF FA BUT SAT LOOP AND AREA WEB CAMS SHOWING HIGH CLDNS RAPIDLY APPRCHG FROM THE WEST. GIVEN THE EXTREMELY DRY AIRMASS (DP TMPS IN THE SINGLE DIGITS AND TEENS)...XPCT TMPS TO DROP OFF SOME THIS EVENING THEN STEADY OUT OR SLOWLY RISE AFTR MIDNITE DUE TO INCRG CLDNS AND WAA FROM THE S-SW WIND. COLDEST READINGS WILL BE ALONG THE COAST WHERE A FEW SUB FREEZING READINGS ARE PSBL ACROSS THE LWR MD ERN SHORE BEFORE RISING LATE. LOWS IN THE 30S. QUICK LOOK AT THE RAP/HRRR/SREF INDICATES LTL IN THE WAY OF PCPN BEFORE 09Z DUE TO THE XTREMELY DRY COLUMN...SO ADJUSTED THE GRIDS IN THE 06-09Z TIME FRAME A BIT. BEST CHC FOR ANY PCPN HERE WOULD BE ACROSS INTERIOR NRN MOST CNTYS WEST OF THE BAY (LOUISA-BOWLING GREEN-COLONIAL BEACH LINE) SO KEPT CHC POPS THERE. OTW...DRY THRU 09Z. DATA THEN SUGGESTS MOISTURE INCREASES AHEAD OF THE APPRCHG COLD FRONT ALLOWING THE AREA OF SHWRS TO EXPAND TO COVER MOST OF THE FA WEST OF THE BAY BTWN 09-12Z. THUS...KEPT CHC POPS THERE WITH A BUFFER ZONE OF SLGHT CHC POPS ALONG THE COAST. WITH BETTER MIXING CONDITIONS PRESENT AND THICKNESSES NOT FALLING TO CRITICAL THRESHOLDS FOR FROZEN PRECIP UNTIL BEHIND THE SFC FRONT XPCT MAINLY RAIN FORECAST LATE TONIGHT INTO MON MORNING. SFC WET BULBS NEAR FREEZING COULD SUPPORT SOME IP MIXING WITH RAIN AT THE ONSET OF PRECIP...SPCLLY ACROSS NRN MOST CNTYS. THE SFC FRONT EXITS THE COAST MON AFTN...BRINGING AN END TO PRECIP AT THE SE COAST AND A WIND SHIFT TO WLY WINDS. WINDS WILL AVERAGE 10-15 MPH WITH GUSTS OF 20-25 MPH. THE BREEZY DOWNSLOPING WIND CONDITIONS WILL HELP TO BOOST TEMPERATURES INTO THE LOWER 60S WITH UPPER 50S AT THE IMMEDIATE COAST. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... WEAK SFC RIDGING...NWLY FLOW ALOFT AND SOME WEAK SHORTWAVE ENERGY CROSSING THE REGION MON NIGHT WILL RESULT IN SOME PASSING HIGH CLOUDS OVERNIGHT MON NIGHT. LOWS WILL BE AROUND SEASONAL NORMALS WITH READINGS IN THE UPPER 30S TO LOWER 40S. FOR TUESDAY...A FAST MOVING LOW PRESSURE SYSTEM DRIVEN BY ZONAL FLOW ALOFT TRACKS ACROSS THE NRN MID ATLANTIC TUESDAY AFTERNOON. EXPECT MOSTLY SUNNY CONDITIONS TO BEGIN THE DAY WITH INCREASING CLOUDS ACROSS THE NORTH AS THE DAY PROGRESSES. A RIBBON OF 20-30% POPS (FOR -SHRA) HAS BEEN MAINTAINED FOR PRIMARILY THE NRN INTERIOR VA COUNTIES AND THE MD LOWER EASTERN SHORE FOR TUE AFTN/EVENING AS LOW PRESSURE CROSSES THE NRN MID ATLANTIC REGION. IT WILL BE DIFFICULT TO GET ANY PCPN S OF THE LOW TRACK WITH DEEP LAYERED WSW FLOW. LOW LEVEL THICKNESS VALUES SUPPORT HIGHS APPROACHING 70F ON TUESDAY OVER INTERIOR VA/NE NC. THIS IS CERTAINLY POSSIBLE WITH LOW PRESSURE TRACKING NORTH OF THE REGION...RESULTING IN DEEP LAYERED WSW FLOW. EXPECT HIGHS IN THE UPPER 60S OVER THE AFOREMENTIONED AREAS...WITH LOWER 60S OVER THE MD/VA ERN SHORE...AND LOCALLY COOLER VALUES ALONG THE IMMEDIATE ATLANTIC COAST. LOW PRESSURE EXITS THE DELMARVA AFTER MIDNIGHT TUE NIGHT...FOLLOWED BY HIGH PRESSURE ON WED. LOWS WILL RANGE FROM THE LOW-MID 40S NORTH OF INTERSTATE 64 TO MID-UPPER 40S SOUTH OF INTERSTATE 64. A SLIGHT COOL DOWN ANTICIPATED FOR WED WITH HIGH PRESSURE BUILDING IN AND LIGHT NLY WINDS. HIGHS SHOULD RANGE FROM 65 SW TO 55 NE. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... SPLIT FLOW CONTINUES TO BE PROBLEMATIC DURING THE EXTENDED PERIOD...BUT MODELS CONTINUE TO COME INTO BETTER AGREEMENT WITH A LATE WEEK FRONTAL PASSAGE. TO BEGIN THE EXTENDED...HIGH PRESSURE PRESSURE SLIDES OFFSHORE WEDS NIGHT. INCREASING SLY FLOW ON THE BACK SIDE OF THE DEPARTING HIGH AND A FLATTENING SRN STREAM WAVE WILL PUSH A WARM FRONT THRU THE LOCAL AREA THURS. RESULTANT WAA WILL PUSH TEMPS INTO THE LOW 70S INLAND AND LOW-UPPER 60S ERN SHORE AND COASTAL AREAS. MODEL CONSENSUS IS TO KEEP THURS FRONTAL PASSAGE DRY THANKS TO LIMITED MOISTURE AND A LACK OF APPRECIABLE FORCING. HAVE REMOVED SLIGHT CHANCE POPS OVER THE PIEDMONT THURS. POTENT NRN STREAM WAVE LOCATES OVER THE GREAT LAKES REGION THURS NIGHT-FRI PUSHING AN ASSOCIATED/DEEPENING SFC LOW INTO SE CANADA. ATTENDANT COLD FRONT PROGGED TO REACH THE CNTRL APPALACHIANS DURING THE LATE THURS-FRI TIMEFRAME. GFS CONTINUES TO BE LESS AMPLIFIED WITH THE NRN STREAM SYSTEM...PUSHING THE FRONT THRU THE REGION AROUND 12 HR QUICKER THAN THE MORE AMPLIFIED/SLOWER ECMWF. REGARDLESS OF SPATIAL AND TIMING DIFFERENCES...EXPECT INCREASING CHANCES FOR PRECIP BEGINNING THURS NIGHT AND CONTINUING THRU SAT. 28/12Z ECMWF PUSHES THE PRECIP OFFSHORE FRI NIGHT...BUT THE GFS STALLS THE FRONT OVER THE REGION THROUGH SAT. HAVE MAINTAINED SLIGHT CHANCE TO LOW END CHANCE POPS SAT TO ACCOUNT FOR UNCERTAINTY. MILD TEMPS EXPECTED THURS NIGHT BEHIND THE WARM FRONT...WITH TEMPS GENERALLY IN THE LOW- MID 50S. WARM SECTOR/SWLY FLOW PUSHES TEMPS INTO THE MID 70S INLAND (POSSIBLY WARMER DEPENDING ON CLOUD COVER) AND UPPER 60S-LOW 70S ERN SHORE AND COASTAL AREAS. COOLER SAT WITH HIGHS MID 60S INLAND AND UPPER 50S-LOW 60S ERN SHORE AND COASTAL AREAS. HIGH PRESSURE PROGGED TO BUILD OVER THE SE STATES SAT NIGHT-SUN...WITH DECREASING CHANCES FOR PRECIP. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... CENTER OF SFC HI PRES HAS SHIFTED OFF THE SOUTHEAST COAST AS OF 00Z. THIS HAS ALLOWED WINDS TO SHIFT TO THE SW. A WEAK COLD FRONT WILL CROSS THE AREA ON MON... BRINGING A CHC FOR SHOWERS FOR THE NWRN HALF OF THE AREA (INCLUDING KRIC/KSBY) BEFORE DAWN MON MORNING AND ACROSS THE SERN HALF OF THE AREA AFTER DAYBREAK MON MORNING. ALL SHOWER ACTIVITY IS EXPECTED TO END BY MON AFTN. WINDS WILL SHIFT TO THE NW BEHIND THE FRONT BEFORE QUICKLY BACKING TO W/SW BY MON NIGHT. HIGH PRESSURE BUILDS BACK INTO THE SE US TUESDAY BUT A COLD FRONT MOVING THROUGH THE AREA MAY BRING A FEW SHOWERS TO KSBY TUE EVENING. WED/WED NIGHT WILL BE DRY AS HIGH PRESSURE BUILDS IN FROM THE NORTH. && .MARINE... HIGH PRESSURE HAS CENTERED OVER ERN SC THIS AFTERNOON...EXTENDING NWD OVER THE LOCAL WATER. THE RESULT IS SUB-SCA CONDITIONS...WITH NWLY WINDS AOB 15 KT...WAVES 1-2 FT AND SEAS 3-4 FT. SFC RIDGE AXIS PUSHES OFFSHORE THIS EVENING WITH WINDS BECOMING SSWLY TONIGHT. THE NEXT COLD FRONT APPROACHES FROM THE NW TONIGHT...CROSSING THE WATER LATE MON. GRADIENT WINDS INCREASE ALOFT LATE TONIGHT-MON MORNING...BUT WAA OVER COLD WATER WILL RESULT IN A SHARP LOW LEVEL INVERSION. MODELS CONTINUE TO INDICATE SW WINDS OF 15-20 KT OVER THE BAY AND 20-25 KT OVER THE COASTAL WATERS LATE TONIGHT-EARLY MON MORNING...BUT DO NOT ANTICIPATE HIGHER VELOCITY WINDS ALOFT TO MIX TO THE WATER DUE TO AFOREMENTIONED INVERSION. HAVE CAPPED SPEEDS AT 15 KT IN THE BAY AND 20 KT COASTAL WATERS. HAVE ALSO UNDERCUT WAVEWATCH DUE TO GFS WINDS BEING TOO STRONG. LOCAL STUDIES ALSO SUGGEST BRIEF S-SWLY FETCH WILL HAVE TROUBLES BUILDING SEAS TO 5 FT IN THE NRN WATERS. AS A RESULT...NO SCA HEADLINES ARE PLANNED ATTM. SCA CONDITIONS ALSO NOT ANTICIPATED POST FRONTAL MON NIGHT DUE TO WEAK GRADIENT WINDS AND LIMITED CAA. HIGH PRESSURE BRIEFLY BUILDS OVER THE WATERS MON NIGHT-TUES MORNING WITH THE FLOW SWITCHING FROM THE NW BACK TO THE SW TUES. LOW PRESSURE AND AN ATTENDANT COLD FRONT APPROACH THE WATER TUES...CROSSING THE WATER TUES NIGHT. SCA CONDITIONS ARE POSSIBLE POST FRONTAL TUES NIGHT-WEDS MORNING. HIGH PRESSURE RETURNS TO THE WATER WEDS-THURS...RESULTING IN SUB-SCA CONDITIONS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...BMD/MPR NEAR TERM...BMD/MPR SHORT TERM...AJZ/BMD/JAO LONG TERM...SAM AVIATION...JDM/DAP MARINE...SAM CLIMATE...

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.