Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 221438 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1038 AM EDT FRI AUG 22 2014 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE ALONG A STALLED FRONTAL BOUNDARY ACROSS THE MID ATLANTIC STATES LATE TODAY AND TONIGHT. THE FRONT WILL PUSH SOUTHWEST AS A COLD FRONT SATURDAY. HIGH PRESSURE WILL BUILD SOUTH FROM NEW ENGLAND INTO THE MID ATLANTIC THIS WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/... XPCTG M CLDY TO OVC SKIES THIS AFTN AS THE BNDRY RMNS STALLED ACROSS THE RGN. 12Z IAD SNDG SHOWS A LGT WIND FIELD...NOT UNCOMMON FOR THIS TIME OF YR. IF THERE IS A THREAT TDA IT WOULD LKLY BE ANY HVY RA CELLS THAT FORM WOULD NOT BE MOVG TOO FAST...ALTHO NOT XPCTG FLSH FLD CONDS TO DVLP. CLDY SKIES ALSO HELPING TO LIMIT TEMPS FM RISING TOO QUICKLY. HIGHS XPCTD TO BE IN THE LM80S. PRVS DSCN... SUNSET WILL AGAIN BE THE START OF TSTM DISSIPATION W/ ONLY A HANDFUL OF SHOWERS CONTINUING TO SLIDE ACROSS THE AREA INTO THE LATE NIGHT HRS. DEWPOINTS WILL CONTINUE TO HOVER NEAR 70F FOR ANOTHER HUMID OVERNIGHT. BATCHES OF MID CLOUD DECKS WILL ALSO HELP SHELTER THE AREA AND KEEP OVERNIGHT LOWS MODERATED NEAR THE 70F MARK. TOWARD SUNRISE SAT...THE DYNAMIC TRANSITION WILL BEGIN TO TAKE PLACE OFF TO OUR NORTH AND EAST. THE UPPER LOW SITTING OVER THE GREAT LAKES FOR THE PAST COUPLE OF DAYS WILL BE ABSORBED INTO THE UPPER FLOW AND HELP DIG THE RETROGRADED PORTION OF AN UPPER TROUGH BACK OVER THE AREA ON SAT. THE LAST ARM OF THIS FEATURE WILL DRIFT ACROSS THE REGION DURING THE DAYTIME HRS AND BRING MORE SCATTERED SHOWERS AND TSTMS. HIGH TEMPS WILL BE THEIR COOLEST IN DAYS BUT STILL REACHING THE L80S BY MID AFTN. HOWEVER...THE INSTABILITY PROFILE WILL LOOK MORE LIKE THU`S...W/ SFC-BASED CAPES POTENTIALLY IN THE 1-1.5K RANGE W/ A COOLER UPPER LEVEL TEMP PROFILE FROM THE UPPER TROUGH PASSAGE. STABILITY MAY COME HOWEVER IN THE FORM OF AN ELY LOW LEVEL WIND...WHICH COULD LIMIT THE CONVECTIVE INITIATION POTENTIAL IF THE CAP IS TOO STRONG AND SFC TEMPS DON`T REACH THE APPROPRIATE LEVELS - ESPEC CLOSER TO THE BAY AND NEAR THE MASON-DIXON LINE. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... SFC HIPRES WL BE BLDG DOWN THE COAST SAT NGT-SUN. AS H5 RDG AXIS CONTS TO SHARPEN...DRIER AIR WL BE ENTRAINED...AND GRDLY ERODE THE LLVL MARITIME SATURATION. THAT WL HPPN FIRST ALONG I-95 SAT EVNG. THINK WE/LL NEED TO HOLD ONTO POPS FOR THE MTNS ALL NGT SAT. FIRST CLRG WL COME TO METRO BALT ELY SUN...AND WL SPREAD THAT TO THE SW ACRS THE REMAINDER OF THE CWFA THRUT THE DAY. SUNDAY WL BE A NICER DAY THAN SAT...EVEN FOR THE MTNS WHICH MAY AVG OUT AS PTSUN VS MOSUN /OR EVEN SUNNY/. SINCE ITLL BE CLDY...AND DEWPTS WL BE DROPPING THRU THE 60S...DIDNT LWR MIN-T AS MUCH AS I CUD HV. AM TAKING A RESERVED APPROACH...W/ MIN-T IN THE 60S AS WELL. DID GO ON THE COOLER EDGE OF MAXT GDNC FOR SUN...BUT BELIEVE PROLONGED ELY FETCH WL KEEP TEMPS FAIRLY CLOSE TO WATER TEMPS. && .LONG TERM /MONDAY THROUGH THURSDAY/... SFC HIPRES AND H5 RDG AXIS CONT TO BUILD OVER THE MID ATLC THRU THE XTNDD PD. FLOW WL BE LGT...BUT TEMPS WL GRDLY BE MODERATING BY MIDWEEK. A CDFNT DROPPING TWD THE AREA LT WK WL PROVIDE THE ONLY PCPN RISK DURING THE WORK WEEK. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... M CLDY SKIES TDA...ALTHO VFR. SCATTERED SHOWERS AND LATE-DAY TSTMS POSSIBLE AGAIN ACROSS THE REGION. CONDS WILL IMPROVE AGAIN OVERNIGHT...THOUGH A FEW ISOLATED SHOWERS AND MORE DENSE CLOUD COVER IS EXPECTED INTO EARLY SAT W/ MORE SHOWER/TSTMS EXPECTED ON SAT. MAY HV SOME LOW CLDS OR PATCHY FOG TO START THE DAY SUN...OTRW VFR WL PREVAIL THRU TUE. && .MARINE... SCA CONDITIONS NOT ANTICIPATED TODAY OR TONIGHT. A FEW TSTMS POSSIBLE THIS AFTN/EVE OVER THE WATERS. ELY ONSHORE FLOW WILL STRENGTHEN INTO EARLY SAT...W/ SOME POSSIBLY MARGINAL SCA CONDITIONS ALONG THE WRN SHORES AND MAIN STEM OF THE MD BAY. ELY/NELY FLOW WL PREVAIL SAT NGT INTO SUN AS HIPRES DRAINS COOLER/DRIER AIR ACRS WATERS. GDNC SUGGESTS WNDS WL REMAIN AOB 15 KT DURING THIS TIME. WL GO THAT ROUTE IN THE FCST ATTM...BUT WUDNT BE SHOCKED IF A FEW HIER GUSTS APPROACHED SCA CRIT IN THE MAIN CHANNEL OF THE MID BAY. BYD THAT...WNDS WL LESSEN AS HIPRES BLDS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ UPDATE...WOODY! PRVS...GMS/HTS

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