Area Forecast Discussion
Issued by NWS Wakefield, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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. --
723 FXUS61 KAKQ 172329 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 729 PM EDT SUN MAY 17 2015 .SYNOPSIS... HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST THROUGH TUESDAY. A COLD FRONT CROSSES THE REGION TUESDAY NIGHT. HIGH PRESSURE BUILDS INTO THE AREA FROM THE WEST WEDNESDAY THROUGH SATURDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... DESPITE THE MODELS BEING LOADED WITH ENOUGH MOISTURE FOR PCPN TO OCCUR...NOT MUCH ACTIVITY HAS DEVELOPED ACROSS THE FA PAST FEW HOURS. AREA OF SHWRS/TSTRMS OVER SERN VA HAS WEAKENED AS WELL. WITH THE DAYTIME HEATING WANING...WENT AHEAD AND LOWERED THE POPS ACROSS VA/MD THIS EVE TO 20-30%...KEEPING NC COUNTIES DRY FOR NOW. A SHWR STILL PSBL AFTR MIDNITE GIVEN HOW MOIST THE AIRMASS IS. LOWS 65-70. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... OVERALL, EXPECT SFC HIGH PRESSURE TO REMAIN ANCHORED OFF THE SOUTHEAST COAST. MEANWHILE, AFOREMENTIONED FRONTAL BOUNDARY TO THE NORTH WILL BE SHUNTED EAST ACROSS MID-SOUTH AND OHIO VALLEY MONDAY NIGHT, AS A CLOSED UPPER LOW SLOWLY FILLS AS IF LIFTS NORTHEAST TOWARD THE UPPER GREAT LAKES MONDAY INTO EARLY TUESDAY. THIS WILL SERVE TO DAMPEN THE UPPER LEVEL RIDGE AS IT SHIFTS EAST OVER THE REGION. PRESSURE FALLS ON THE LEE SIDE OF THE APPALACHIANS WILL RESULT IN A SHARPENING LEE/THERMAL TROUGH OVER THE PIEDMONT INTO CENTRAL VA, WHICH SHOULD SERVE TO PROVIDE BETTER LOW LEVEL CONVERGENCE AND MODEST FORCING FOR ASCENT. THUS, EXPECTING MORE WIDESPREAD CONVECTIVE DEVELOPMENT ON MONDAY. BEST UVM EXPECTED IN THE AFTERNOON AS WEAK PERTURBATIONS ROUND THE RIDGE, DROPPING E-SE ACROSS THE LOWER MID-ATLANTIC. SHEAR REMAINS MARGINAL UNDERNEATH THE DAMPENING UPPER RIDGE...BUT INCREASING DEWPOINTS AND BETTER INSTABILITY SHOULD BE SUFFICIENT TO SUPPORT PULSE CONVECTION. ACCORDINGLY, THE MUCAPE IS ALSO PROGGED TO BE A BIT HIGHER, GENERALLY IN THE 1000-1500 J/KG RANGE (HIGHEST OUT WEST IN THE PIEDMONT). NO MAJOR SHIFT IN FORECAST THINKING FOR TOMORROW...WITH A FEW STRONG STORMS POSSIBLE WHICH COULD PRODUCE GUSTY WINDS AND SMALL HAIL ON MON. IN ADDITION...PW AROUND +2 STD DEV AND VERY LIGHT STEERING FLOW WILL PRODUCE LOCALLY HEAVY RAINFALL. TEMPERATURES TOMORROW WILL BE A BIT OF A CHALLENGE, BOTH WITH RESPECT TO MORE WIDESPREAD CONVECTIVE DEVELOPMENT, BUT ALSO WITH THE BACKDOOR FRONT...WHICH IS DEPICTED SIMILARLY BY 12Z/17 MODEL DATA DROPPING SOUTH ACROSS OVER THE NE COUNTIES MON AFTN/EARLY EVENING. GFS REMAINS THE MOST AGGRESSIVE WITH WARMING...NAM AND EURO MOS ARE SIMILAR AND BOTH SLIGHTLY COOLER WITH HIGHER POP/CLOUD COVERAGE. ECM/MET BLEND IS VERY CLOSE TO OFFICIAL FORECAST, AND HAVE ERRED TOWARD THE COOL SIDE OF THE GUIDANCE ENVELOPE FOR HIGHS TOMORROW. STILL WARM AND MODERATELY HUMID...HIGHS LOW TO MID 80S NORTHEAST COASTAL ZONES...U80S TO NEAR 90 SOUTH. TUESDAY: WEAK SURFACE COLD FRONT CROSSES THE AREA TUESDAY AFTN/NIGHT. BULK SHEAR REMAINS MARGINAL AT BEST AND DOWNSLOPE FLOW ALOFT IS LESS THAN IDEAL FOR WIDESPREAD CONVECTIVE DEVELOPMENT. HOWEVER, STRONG SFC HEATING PRE-FRONTAL SHOULD YIELD ANOTHER ROUND OF SCATTERED SHOWERS & T-STORMS TUESDAY AFTN/EVE. WENT SLIGHTLY COOLER WITH TEMPS ON TUE, WITH EXPECTATION OF INCREASING AFTN CONVECTION. HIGHS MID 80S NORTH...UPPER 80S TO NR 90 SOUTH. WEDNESDAY: SFC COOL FRONT SLOWLY PUSHES FARTHER SOUTH WEDNESDAY, EVENTUALLY BECOMING STALLED ACROSS THE SOUTHEAST LATER IN THE DAY. COOL/DRY HIGH PRESSURE BEGINS TO BUILD TOWARD THE AREA FROM THE WEST ON WEDNESDAY, YIELDING A MUCH DRIER/MORE COMFORTABLE DAY ON WEDNESDAY. LOOK FOR HIGH TEMPS INTO THE MID TO UPPER 70S OVER THE EASTERN SHORE TO LOW 80S INLAND...PERHAPS A FEW MID 80S ACROSS FAR SOUTHERN ZONES. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... SHORTWAVE ENERGY IS PROGGED TO SHEAR AS IT TRAVERSES THE GULF STATES ON THU. MEDIUM RANGE GUIDANCE IS IN AGREEMENT INDICATING A WAVE OF LOW PRESSURE DEVELOPING ALONG A FRONTAL BOUNDARY BY MIDDAY THU IN THU NIGHT OVER THE SE STATES IN RESPONSE TO THE SHORTWAVE. BASED ON THE LACK OF SIGNIFICANT UPPER LEVEL SUPPORT AND RATHER FLAT FLOW... BEST PRECIP CHANCES ASSOCIATED WITH THE WEAK WAVE WILL STAY SOUTH OF THE LOCAL AREA. HOWEVER...A SLIGHTLY MORE NORTHWARD TREND IN THE SFC LOW TRACKING THRU SOUTH CAROLINA WILL LEND THE NECESSITY FOR SLIGHT CHC POPS ACROSS MUCH OF THE AREA THU...THEN MAINLY SERN AREAS THU NIGHT AND FRI. HIGH PRESSURE THEN BUILDS OVER THE REGION FOR THE UPCOMING HOLIDAY WEEKEND...RESULTING IN DRY CONDITIONS. COMFORTABLE THU/FRI WITH HIGHS IN THE 70S. WARMING SLIGHTLY NEXT WEEKEND WITH HIGHS IN THE 70S TO LOW 80S. (HIGH TEMPS COOLER AT THE IMMEDIATE COAST THRU THE PERIOD). LOW TEMPS IN THE MID 50S TO MID 60S. && .AVIATION /00Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
VFR CONDITIONS PREVAIL ALL TERMINALS EARLY THIS EVENING. REMAINING LIGHT RAIN MOVING SEWD THROUGH EXTREME SE VA CONTINUES TO WEAKEN...AND WILL NOT AFFECT KECG. LATEST RDAR TRENDS SUGGEST SHOWERS/TSTMS WEST AND NORTH OF THE REGION WILL NOT MAKE IT INTO ANY OF THE TERMINALS BEFORE NOCTURNAL COOLING TREND CAUSES PRECIP TO WEAKEN AND/OR DISSIPATE. THUS...HAVE KEPT ALL TERMINALS DRY THROUGH 12Z MONDAY. IN ADDITION...HAVE ADDED FOG TO KPHF...WITH SOME POTENTIAL FOR IFR CONDITIONS AFTER 06Z DUE TO PRECIP THIS AFTERNOON AND RELATIVELY CLEAR SKIES AND LIGHT WINDS OVERNIGHT. HAVE ALSO BACKED OFF ON IFR AT KSBY...AS TSECTIONS AND OTHER GUIDANCE DO NOT SUPPORT ANYTHING WORSE THAN MVFR. BACKDOOR FRONT EDGES CLOSER TO THE AREA FROM THE NE ON MONDAY...REACHING KSBY 18Z OR LATER...BUT WASHING OUT BEFORE BECOMING A SIGNIFICANT FACTOR TO OTHER TERMINALS. WITH BOTH BACKDOOR FRONT AND LINGERING CONVECTIVE BOUNDARIES AROUND ON MONDAY...EXPECT THE POTENTIAL FOR AT LEAST SCTD SHOWERS/TSTMS MONDAY AFTERNOON/EVENING. HOWEVER...DUE TO TIMING AND LOCATION UNCERTAINTIES...HAVE LEFT OUT OF 00Z TAFS. ADDITIONAL SHOWERS/TSTMS POSSIBLE AGAIN TUESDAY AS A STRONGER FRONT MOVES INTO THE REGION...THEN ACROSS THE REGION TUESDAY NIGHT. BEHIND THIS FRONT...HIGH PRESSURE BUILDS IN FOR MOST OF THE REST OF THE WEEK.
-- End Changed Discussion --
&& .MARINE... SFC HIGH PRESSURE REMAINS OFF THE SE COAST INTO TONIGHT...RESULTING IN SW WINDS (REMAINING AOB 15 KT)...WAVES ON BAY 1-2 FT...SEAS 2-3 FT. WINDS BECOME VRB/ONSHORE MON AS COMBO WEAK LOW PRESSURE AND BACKDOOR COLD FRONT SETTLES IN OVER THE MID ATLANTIC COAST. THIS WILL ALSO RESULT IN WINDS BECOMING ESE...AND ALSO A HIGH PROBABILITY FOR SHRAS/SCT TSTMS OVR THE WATERS. ANOTHER COLD FRONT PUSHES ACROSS THE WATERS LATE TUE (WITH POSSIBLE SHRAS/TSTMS). WINDS BECOME N-NW POST-FRONTAL TUE NIGHT. ATTM...STILL LOOKS LIKE THE POTENTIAL FOR SCA CONDITIONS TUE NIGHT OVER THE CHES BAY DUE TO A SURGE OF COOLER/DRIER AIR PUSHING OVER THE WATERS BEHIND THE FRONT. FOR NOW...KEEPING NW WINDS AT 15-20 KT...AND WAVES AOB 3 FT ON THE BAY...AND SEAS AOB 4 FT. RATHER BENIGN BOATING CONDITIONS ARE EXPECTED WED/THU. && .EQUIPMENT... KAKQ RADAR REMAINS OFFLINE WITH A AZIMUTH MOTOR ISSUE. TECHNICIANS EXPECT TO REPLACE THE MOTOR MONDAY MORNING. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MPR NEAR TERM...MPR SHORT TERM...MAS/MAM LONG TERM...JDM AVIATION...BMD/WRS MARINE...JDM EQUIPMENT...

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