Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 311411 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1011 AM EDT MON AUG 31 2015 .SYNOPSIS... HIGH PRESSURE WILL REMAIN ANCHORED OFFSHORE TODAY. A TROUGH AXIS WILL PIVOT ACROSS THE REGION THIS AFTERNOON. HIGH PRESSURE WILL REFOCUS OVER THE CENTRAL APPALACHIANS AND UPPER OHIO VALLEY TUESDAY...AND PERSISTS THROUGH THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... DISORGANIZED HIGH PRESSURE EXTENDS FROM THE TN VALLEY TO THE MID- ATLANTIC OFFSHORE WATERS. A WEAKNESS IN THE PRESSURE FIELDS EXTENDS ALONG THE NEW ENGLAND COAST...WITH A REFLECTION IN THE 925-850 MB LAYER INTO OUR NORTHERN CWA. THIS COULD ACT AS A FOCUS/FORCING MECHANISM FOR PRECIP AS THE DAY WEARS ON. THE OTHER IS A VORT MAX LOCATED IN SW VA WHICH WILL BE LIFTING ACROSS THE AREA THROUGH THIS AFTERNOON. SOME ISOLATED MODERATE SHOWERS HAVE ALREADY DEVELOPED...BUT OVERALL COVERAGE HAS BEEN DISORGANIZED. SOME BREAKS IN THE CLOUDS N/W OF DC MAY ALLOW SOME INSTBY TO BE REALIZED AND HAVE LIMITED THUNDER MENTION TO THESE AREAS TODAY. HAVE RELIED ON HRRR/RAP/NAM AND AFOREMENTIONED FEATURES FOR LOCATIONS OF HIGHEST POPS (STILL IN SCATTERED CATEGORY)...ALTHOUGH TOUGH TO RULE OUT PRECIP JUST ABOUT ANYWHERE. IN THE AREAS WITH HIGHER INSTBY...THERE COULD BE A FEW SLOW MOVING HEAVIER SHOWERS. TEMPERATURES WILL DEPEND ON CLOUD COVER...AND LOCATIONS OF BREAKS BECOME MORE UNCERTAIN AS THE DAY PROGRESSES. SO MINIMAL CHANGES TO THE FORECAST MID-80S AT THIS TIME. THE UPR TROF WL CROSS MID-LT AFTN...ABANDONING A POCKET OF LWR HGTS IN THE OHVLY. THE RESULTANT FLOW PTTN SHUD PROMOTE THINNING OF THE CLD DECK. WL BRING CLRG SKIES INTO CWFA FM N TO S...AND CARRY A MOCLR NGT. LOWS WILL FALL CLOSE TO THE DEW POINTS IN THE MID 60S...WITH URBAN AND COASTAL AREAS REMAINING IN THE 70S. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... ALTHO THERE WL BE A CUTOFF LOW WANDERING ARND THE OHVLY /AND SOME GDNC SUGGESTING A CSTL SFC LOW MAY DVLP OFF THE CAROLINAS/...THE RE- EMERGENCE OF RDGG WL BE THE MAIN WX PLAYER LOCALLY. THEREFORE THE SUN AND WARMTH WL DOMINATE. SHUD BE ABLE TO GET CLOSER TO FULL SUN TEMPS...MARKING A 90 DEG DAY FOR MOST AREAS. SUBSEQUENTLY...HV A BETTER CHC AT REACHING CNVCTV TEMPS. WL NEED THE BOOST FROM TRRN CIRCULATIONS...AND HV RESTRICTED 20-30 POPS TO THE SWRN CWFA. TUE NGT MIN-T WL OFFER A HVY DOSE OF PERSISTENCE FM MON NGT. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... A SHORTWAVE TROUGH WILL LIKELY RIDE AN UPPER LEVEL RIDGE WEDNESDAY. MODELS DIFFER WITH INTENSITY AND TIMING OF THE TROUGH BUT THERE IS CONSENSUS THAT THE TROUGH WILL MOVE THROUGH THE REGION OR CLOSE BY. SHOWERS AND THUNDERSTORMS ARE POSSIBLE MAINLY WEST OF THE BLUE RIDGE WEDNESDAY AFTERNOON. THE RIDGE BUILDS BACK INTO THE REGION AS THE SHORTWAVE TROUGH EXITS BY THURSDAY. WARM AND HUMID CONDITIONS WILL LEAD TO THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS MAINLY IN THE AFTERNOON AND MAINLY ALONG THE RIDGE LINES THROUGH FRIDAY. COVERAGE WILL LIKELY BE ISOLATED TO SCATTERED. TEMPS WILL BE AROUND 5 DEG ABOVE CLIMO THROUGH THE END OF THE WORK WEEK. HIGH PRESSURE NOSES INTO THE MID-ATLANTIC FROM THE NORTHEAST THIS WEEKEND AND A BACKDOOR COLD FRONT MAY MOVE INTO THE REGION. THIS MAY RESULT IN DRIER AND COOLER CONDITIONS MAINLY IN THE NE HALF OF THE REGION. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... SHOWER ACTIVITY IS EXPECTED TO REMAIN SCATTERED AND DISORGANIZED TODAY WITH ISOLATED THUNDER THIS AFTERNOON...SO WILL BE TOUGH TO NAIL DOWN ANY IMPACTS. THERE COULD BE A BRIEF PERIOD OF SUB-VFR CONDITIONS SHOULD ONE OF THESE DEVELOP OVER A TERMINAL. SSWLY FLOW AOB 10 KT WL BRING PLENTY OF CLDCVR THO. CIGS MAINLY MID DECK BUT COULD LOWER AT TIMES. PCPN WIDELY SCTD AND LGT. IMPACT TOO LOW TO MENTION. SKIES WL CLR TNGT AS WIND DROP TO BLO 5 KT AND VEER WLY. SINCE RADL COOLING BETTER FOG BECOMES MORE OF A CONCERN. ATTM BEST CHC CHO/MRB. OUTLOOK... TUE-FRI...VFR. && .MARINE... SOUTHERLY TO SOUTHWESTERLY FLOW WILL CONTINUE OVER THE WATERS TODAY. CLDS AND WK PRES PTTN WL KEEP MOST SUSTAINED SPDS NEAR 10 KT. CAN/T RULE OUT AN ISOLATED STORM NEAR DC/BALTIMORE...BUT FOR THE MOST PART ONLY A FEW LIGHT SHOWERS EXPECTED ON THE WATERS. MUCH LESS OF A CHC AT CHANNELING LT TNGT THRU TUE THAN PREVIOUS EVENINGS. HIGH PRESSURE WILL BE IN CONTROL ACROSS THE WATERS WED-FRI. A SFC TROUGH MAY FORM CAUSING WINDS TO SHIFT BUT THEY SHOULD STAY BELOW SCA CONDITIONS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...HTS NEAR TERM...ADS/HTS SHORT TERM...HTS LONG TERM...HAS AVIATION...ADS/HAS/HTS MARINE...ADS/HAS/HTS

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