Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 191748 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 148 PM EDT TUE AUG 19 2014 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL DEVELOP ALONG THE NORTH CAROLINA COAST INTO SOUTHEAST VIRGINIA AND THEN GRADUALLY MOVE OFF THE COAST TONIGHT. WEAK HIGH PRESSURE RETURNS ON WEDNESDAY BEFORE ANOTHER SYSTEM OVER THE GREAT LAKES MOVES INTO THE MID ATLANTIC STATES FOR THURSDAY AND FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... WEAK LOW PRESSURE OVER THE TIDEWATER CONTINUES TO SPIN AND PRODUCE A COUPLE BANDS OF SHOWERS TO THE NORTH OF THIS LOW. THE AREA OF LOW PRESSURE IS ELONGATING AND TRYING TO REFORM FURTHER EAST...A FEW HUNDRED MILES OFF THE COAST...BUT THE LINGERING PRESSURE TROUGH WILL PERSIST THROUGH THE AFTERNOON AND INTO THE EVENING HOURS. THE MODELS SHOW THAT SOME LIFT WILL CONTINUE TO THE NORTH OF THE TROUGH SO HAVE HELD ON TO SOME CHANCE POPS THROUGH THE AFTERNOON BEFORE TAPERING THEM OFF THIS EVENING. ELSEWHERE...HAVE HELD ON TO SOME LOW CHANCE POPS LATE AFTERNOON AND EVENING IN NE NC AS NAM SHOWS THE SHORTWAVE ENERGY OVER SC LIFTING NE AND HELPING TO TRIGGER CONVECTION. OTHERWISE...JUST A SLIGHT CHANCE POP...MAINLY IN THE PIEDMONT DUE TO THE WEAK UPSLOPE FLOW AND LOW LEVEL MOISTURE. BUT COULD EASILY SEE NO PRECIP AT ALL. ELSEWHERE...STILL HAVE LOTS OF LOW LEVEL MOISTURE LINGERING AROUND AND LOTS OF CLOUDS. SATELLITE IS SHOWING SOME BREAKS...BUT WITH ALL THE MOISTURE AROUND...ANY HEATING WILL QUICKLY LEAD TO A SUBSTANTIAL CU FIELD. SUSPECT THAT THE LOWER CEILINGS WILL LIFT INTO A BROKEN CU DECK THIS AFTERNOON. THIS IS TRICKY WITH THE HIGHS TODAY...AS JUST A SHORT PERIOD OF SUN COULD PUSH TEMPS UP ONLY TO HAVE CLOUDS RETURN AND HALT THE WARM UP. BASED UP THE LAV GUIDANCE AND THE CLOUD COVER...HAVE LOWERED THE MAX TEMPS TODAY PRETTY MUCH EVERYWHERE BY A COUPLE DEGREES. FOR TONIGHT...SHOULD SEE SOME IMPROVEMENT AS THE SFC LOW PULLS AWAY FROM THE COAST AND WEAK HIGH PRESSURE NOSES SWD FROM THE NE. THIS WILL BRING A LITTLE DRIER AIR AND SHOULD HELP TO PROVIDE SOME CLEARING ESPECIALLY FOR THE LWR MD ERN SHORE AND THE NRN PIEDMONT. BUT WITH ANY CLEARING COULD SEE SOME PATCHY FOG FORM. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... A MID LEVEL 700MB TROUGH SLIDES ACROSS THE AREA OVERNIGHT AS THE SFC BOUNDARY CONTINUES TO PUSH SWD INTO THE CAROLINAS. THE COMBINATION OF THE FRONTAL PLACEMENT AND THE BASE OF THE MID LEVEL TROUGH BEING SOUTH OF THE FA BY MID-LATE EVENING WILL HELP SHUNT BEST PRECIP WELL TO THE SOUTH (AND OUT OF THE WAKEFIELD CWA) BY MIDNIGHT. THERE MAY BE A FEW LINGERING SHOWERS IN THE PIEDMONT INVOF WARM FRONT EXTENDING FROM A LOW IN THE NRN GREAT LAKES...BUT THEY SHOULD COME TO AN END BTWN MIDNIGHT AND DAYBREAK TUE MORNING. LOWS IN THE UPPER 60S TO LOWER 70S. WEDNESDAY THROUGH THURSDAY NIGHT...NORTHWEST FLOW ALOFT AND TROUGHING OVER THE NE CONUS WILL KEEP UNSETTLED CONDITIONS ACROSS THE AREA DURING THIS PERIOD. WEDNESDAY STILL APPEARS TO BE THE DRIER DAY OF THE TWO DAY TIMEFRAME AS THE EXITING LOW OFF THE COAST ALLOWS FOR WEAK HIGH PRESSURE OVER THE NE TO NOSE SOUTHWARD INTO THE MID ATLANTIC STATES...LESSENING THE MOISTURE AS COMPARED TO THE PAST FEW DAYS. BUT BY THURSDAY...THE NW FLOW IS MORE ESTABLISHED AND WITH CONVECTION TO THE NORTHWEST AND THE REGION IN A GOOD POSITION ON THE EDGE OF THE RIDGE...COULD EASILY SEE CONVECTION DROP SE INTO THE REGION. SO HAVE VERY LITTLE PCPN ON WEDNESDAY WITH HIGHER CHANCE POPS ON THURSDAY. TEMPERATURES COULD BE TRICKY DUE TO VARYING PERIODS OF CLOUDS VERSUS SUN BUT SHOULD GENERALLY BE IN THE MID-UPPER 80S (AROUND 80 AT THE BEACHES DUE TO ONSHORE FLOW). LOWS NEAR 70. && .LONG TERM /FRIDAY THROUGH MONDAY/... UNSETTLED WEATHER PATTERN CONTINUES INTO THE EXTENDED PERIOD AS NWLY FLOW ALOFT DEVELOPS. TEMPS WILL BE NEAR TO SLIGHTLY BELOW SEASONABLE...LATE SUMMER NORMS. WHILE MEDIUM RANGE GUIDANCE CONTINUES TO STRUGGLE HANDLING THE SPLIT/BLOCKY FLOW OVER THE HIGHER LATITUDES...MODELS HAVE BECOME MORE STABLE WITH RESOLVING SRN STREAM ENERGY OVER THE OH VALLEY AND MID-ATLANTIC REGION. THIS THANKS TO UPPER/SFC HIGH PRESSURE FROM THE SE STATES EWD OFF THE COAST. WITH THAT SAID...FLOW AMPLIFIES OVER THE ERN CONUS AS MID LEVEL HIGH PRESSURE BUILDS OVER THE CNTRL US AND LOW PRESSURE REMAINS OVER THE NE US. THIS WILL PLACE THE MID-ATLANTIC STATES IN NWLY FLOW ALOFT...OPENING THE DOOR FOR SHORTWAVE ENERGY IN THE UPPER FLOW. QUASI-STATIONARY BOUNDARY WILL LOCATE OVER THE REGION...JUST TO THE SOUTH. MOISTURE WILL NOT BE A LIMITATION WITH PWATS PROGGED AROUND 2 INCHES (+1 STD DEV) AND DEWPOINTS IN THE MID-UPPER 60S. ANTICIPATE A DIURNAL TREND WITH SHOWERS/THUNDERSTORMS...BUT UPSTREAM MCS DEVELOPMENT MAY SPILL INTO THE REGION DURING THE OVERNIGHT HOURS THRU THE WEEKEND. HIGHER POPS MAY BE WARRANTED...BUT BASED ON THE DEGREE OF UNCERTAINTY AND TIMING...WILL STICK MORE TO CLIMO WITH CHANCE POPS DURING THE AFTERNOON AND EVENING. COULD BEGIN TO SEE A DRYING TREND BY LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS THE UPPER HIGH BUILDS EWD...SHUNTING THE BEST MOISTURE OFFSHORE. WITH THE LATEST MODEL RUNS PLACING THE FRONT SOUTH OF THE LOCAL AREA...NLY FLOW AND FALLING THICKNESSES WILL LIKELY YIELD TEMPS IN THE LOW-MID 80S. LOW-MID 80S TO CONTINUE THRU THE WEEKEND...WARMING BACK INTO THE MID 80S BY EARLY NEXT WEEK. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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WEAK LO PRES WILL SLOWLY MOVE ENE AWAY FM THE VA/NC CST LATER THIS AFTN THRU WED. EXPECTING MAINLY VFR/MVFR CONDITIONS THRU THE TAF PERIOD...WITH SCTD -RA INTO THIS EVENG POSSIBLE AT PHF/ORF/ECG/RIC. ISLTD IFR CONDITIONS AT PHF/ORF DUE TO THE -RA. POTENTIAL REDEVELOPMENT OF IFR CONDITIONS LATE TNGT OR EARLY WED MORNG...AS WINDS REMAIN ONSHORE. SLO IMPROVEMENT WED MORNG...WITH MAINLY VFR CONDITIONS FM LATE MORNG/MIDDAY THRU THE AFTN HRS WITH ONLY ISLTD CONVECTION...ESPLY AWAY FM THE CST. ISLTD TO SCTD CONVECTION POSSIBLE MAINLY THU AND FRI AFTN/EVENGS...AS MORE WEAK FRONTS OR SHRTWV ENERGY AFFECTS THE REGION.
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&& .MARINE... LO PRES EXITS VA CAPES THIS MRNG...THEN CONTS E THROUGH REST OF THE DAY. WNDS BECOMING NNE ACRS ALL WTRS BY THIS AFTN/EVE. SPEEDS AVGG MNLY AOB 15 KT...W/ SEAS ON OCN SLO TO INCRS (BY ABT A FOOT). CONTD MNLY NE WNDS TNGT THROUGH WED W/ SPEEDS AVGG AOB 15 KT. SOME INCRS OF SEAS ON THE OCN...BUT GENLY RMNG SUB-SCA. KEEPING MNLY ONSHORE WNDS THROUGH THU AS WK AREA OF LO PRES DEVELOPS INVOF WTRS (CONDS RMNG SUB-SCA). && .AKQ WATCHES/WARNINGS/ADVISORIES...
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MD...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR MDZ025. NC...NONE. VA...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR VAZ099-100. MARINE...NONE.
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&& $$ SYNOPSIS...BMD NEAR TERM...BMD/ESS SHORT TERM...BMD LONG TERM...SAM AVIATION...TMG MARINE...ALB

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