Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 221905 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 305 PM EDT WED JUL 22 2015 .SYNOPSIS... HIGH PRESSURE OVER THE OHIO VALLEY AND GREAT LAKES WILL DOMINATE OVER THE NEXT SEVERAL DAYS. THE HIGH WILL SHIFT EAST OVER THE WEEKEND...ALLOWING A COLD FRONT TO MOVE IN FROM THE NORTHWEST LATER SUNDAY AND MONDAY. THE FRONT MAY STALL OUT OVER THE REGION ON TUESDAY. && .NEAR TERM /THROUGH THURSDAY NIGHT/... BROAD HIPRES ACRS MUCH OF THE CONUS TAFTN. P-GRAD FROM YDA/S LOPRES/CDFNT STILL ACRS THE NERN CONUS. THE FNT ITSELF NOT WELL PRONOUNCED IN THE PRES PTTN...BUT THERMALLY IT APPEARS TO BE SITUATED SOUTH OF NC/TN. DIURNAL CU FM ERN PA/WRN MD/NRN WVA TAFTN MAY DRIFT SEWD LT TAFTN BEFORE DSPTG W/ SUNSET THIS EVNG. THERE/S A WK VORT EMBEDDED W/IN NW FLOW WHICH WL BE CROSSING AREA. MAY ALSO SEE A FEW ASSOCD 15-20 KT WIND GUSTS. MIN-T FCST GDNC IN DECENT AGREEMENT...AND SHUD BE A LTL HIER THAN DEWPTS-- MID 50S-MID 60S OUTLYING AREAS TO UPR 60S/NEAR 70F IN THE URBAN CENTERS. WK SFC LOPRES SHUD BE TRAVERSING THE FRNTL BNDRY THU AFTN-EVNG. GFS A BIT FURTHER N THAN NAM. STILL SHUDNT IMPACT CWFA DIRECTLY EITHER WAY...BASED ON CURRENT SOLNS. HV KEPT POPS/WX DRY...BUT THE GRADIENT LURKS JUST SE OF CWFA. IF LATER SOLNS TREND NWD...MAY NEED TO ADD POPS TO SERN CWFA. OTRW...MOSUN SKIES WL PREVAIL AS SFC-H8 RDG WL REMAIN NW OF CWFA PROVIDING SUBSIDENCE. H8 TEMPS REMAIN SIMLR THRU THE PD...AND WL DO LIKEWISE FOR MAXT AND MIN-T FCSTS. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... HIGH PRESSURE OVER THE OHIO VALLEY WILL DOMINATE CONDITIONS ON FRI WITH MOSTLY SUNNY SKIES AND NW FLOW... ALLOWING FOR TEMPS SLIGHTLY BELOW NORMAL OVER OUR REGION. COOLER- THAN-NORMAL CONDITIONS WILL CONTINUE INTO FRI NIGHT WITH NW FLOW AND LOW HUMIDITY. HIGH PRESSURE MOVES OFFSHORE SAT AND THE FLOW WILL TURN MORE SOUTHERLY... BRINGING AN INCREASE IN HUMIDITY AND TEMPS THAT ARE CLOSER TO NORMAL. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... HIGH PRESSURE FROM NEW ENGLAND TO THE MID ATLANTIC COAST WILL PROMOTE DRY CONDITIONS WITH SEASONABLE TEMPERATURES SATURDAY NIGHT. AN UPPER LEVEL TROUGH OF LOW PRESSURE AND ITS AFFILIATED SURFACE COOL FRONT WILL PUSH ACROSS THE MID ATLANTIC REGION SUNDAY INTO SUNDAY NIGHT...BRINGING A CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS. THE BEST CHANCE DURING THE DAY SUNDAY WILL BE IN THE POTOMAC HIGHLANDS AND THE SHENANDOAH VALLEY WITH THE CHANCE EXTENDING EASTWARD TO THE I-95 CORRIDOR AND CHESAPEAKE BAY SUNDAY NIGHT. THE COOL FRONT SHOULD STALL ACROSS SOUTHERN MARYLAND AND CENTRAL VIRGINIA MONDAY AND MONDAY NIGHT...ALLOWING FOR THE CHANCE OF SHOWERS AND THUNDERSTORMS TO LINGER. THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WOULD BE MAINLY SOUTHERN MARYLAND AND CENTRAL VIRGINIA...ALTHOUGH THERE IS A SLIGHT CHANCE AS FAR NORTH AND WEST AS THE POTOMAC HIGHLANDS. WEAK HIGH PRESSURE...BOTH AT THE SURFACE AND AT THE MID LEVELS...WILL ATTEMPT TO BUILD IN FROM THE WEST TUESDAY AND TUESDAY NIGHT. WE`LL KEEP A CHANCE FOR SHOWERS AND A THUNDERSTORM OR TWO IN THE REGION AS WE COULD BE PINNED BETWEEN A DISSIPATING FRONT TO OUR SOUTH AND SOME LOW PRESSURE ENERGY MOVING ACROSS OHIO AND PENNSYLVANIA. THE HIGH DOESN`T APPEAR TO BE STRONG. THROUGH THE DAY WEDNESDAY...WEAK HIGH PRESSURE SHOULD HOLD ONTO THE REGION AND FOR THE MOST PART MOST PLACES WILL BE DRY. HOWEVER...A PERSISTENT ZONAL FLOW WITH WEAK INTERMITTENT SHORTWAVES OF ENERGY COULD SPAWN A FEW SHOWERS OR A RUMBLE OF THUNDER...MAINLY IN THE MOUNTAINS. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... NW FLOW TAFTN. HV HAD SOME 15-20 KT GUSTS PICK UP SINCE 18Z. BELIEVE SUNSET SHUD SPELL THE END OF THESE...AS WELL AS THE SCT CU /BASES 040-060/. LIGHTER NW WNDS TNGT-TMRW. DIURNAL CU ONCE AGN TMRW... W/ SIMLR BASES. VFR THRU ENTIRE PD. FRI THRU MON...VFR. && .MARINE... WINDS ON THE WATERS TAFTN HV BEEN LESS THAN ON LAND...WITH SOME HINT OF AN ONSHORE OR SLY FLOW DVLPG AHD OF A S/WV. WL BE KEEPING GUSTS BLO SCA THRESHOLDS...ALTHO ADMITTEDLY IT WL BE A LOT CLSR ON THE NRN BAY THAN PREV THOUGHT. WL ISSUE A STMT IF IT PROVES NCSRY. ANY GUSTS SHUD END W/ SUNSET...AND WNDS SHUD BE LGT BY SUNRISE. NW FLOW WL CONT INTO THU...BUT SPDS AOB 10 KT. SUB-SCA CONDITIONS EXPECTED FOR FRI AND SAT. SMALL CRAFT ADVISORIES ARE POSSIBLE SUNDAY...MAINLY DURING THE AFTERNOON...AS WINDS COULD GUST OVER 20 KNOTS AT TIMES. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...RCM/HTS NEAR TERM...HTS SHORT TERM...IMR LONG TERM...KLW AVIATION...HTS/IMR/KLW MARINE...HTS/IMR/KLW

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