Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 230254 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1054 PM EDT FRI MAY 22 2015 .SYNOPSIS... A COLD FRONT WILL PUSH SOUTH OF THE AREA TONIGHT. HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY. THE HIGH WILL MOVE OFF THE COAST SUNDAY AND REMAIN IN THE WESTERN ATLANTIC THROUGH MID- WEEK NEXT WEEK WITH NOTICEABLY HOTTER AND MORE HUMID CONDITIONS RETURNING TO THE REGION. && .NEAR TERM /THROUGH SATURDAY/... LTST SFC ANALY DEPICTS CDFNT DRAPED ACRS THE CWFA. ISOL SHRA FOUND AT THE END OF THE DAY HV SINCE DSPTD W/ THE SETTING SUN. FOR THAT MATTER...MOST OF THE CLDS HV EVAPORATED AS WELL. WL STILL BE CARRYING A PD OF PTCLDY SKIES TO ACCOMPANY THE FNT...WHICH SHUD CLR SRN ZNS BY OR SHORTLY AFTR MIDNGT. WNDS HV ALSO STARTED TO RESPOND TO THE LOSS OF DIURNAL MIXING. MOST OF THE HIER GUSTS SHUD CEASE BY 01 OR 02Z. HWVR...BASED ON ANTICIPATED NIGHT TIME CAA...AM HESITANT ON ELIMINTING WINDS COMPLETELY. THAT PLAYS INTO THE OVNGT TEMP FCST. DRY AND CLEAR CONDITIONS WILL ALLOW TEMPS TO DROP INTO THE 40S WITH THE EXCEPTION OF THE METROS/BAYSHORE SEEING THE 50S AND THE HIGHER ELEVATIONS OF THE ALLGHENY FRONT SEEING THE MID-UPR 30S. LTST LAMP DATA GENERALLY IN SYNCH W/ THESE THOUGHTS. DID MAKE A CPL MINOR ADJUSTMENTS...MAINLY TO SHAVE ANTHR DEGF OR TWO OFF FOR SITES WHERE CLIMO TENDS TO BE SHELTERED VLYS. HWVR...CONSIDERING HOW LOW DEWPTS WL BE BY MRNG AND THE UNCERTAINTY REGARDING FULL DCPLG...DID NOT ADD ANYONE ELSE TO CURRENT FROST ADVY. IT REMAINS IN PLACE FOR THE WRN FRINGE OF THE CWFA BTWN ALLEGANY AND PENDLTN CNTYS. HIGH PRESSURE MOVES OVERHEAD SATURDAY. NLY FLOW WILL KEEP TEMPS BELOW CLIMO IN THE UPPER 60S TO LWR 70S. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... SURFACE HIGH PRESSURE WILL DRIFT EAST INTO THE ATLANTIC OCEAN SATURDAY NIGHT...BUT THE RETURN FLOW WILL BE SLOW AND LOWS WILL ONLY BE A FEW DEGREES MILDER ON SATURDAY NIGHT AS COMPARED TO FRIDAY NIGHT. HUMIDITY WILL START TO COME BACK HOWEVER. OTHERWISE...SKIES SHOULD BE MOSTLY CLEAR AS HEIGHTS ALOFT BUILD AHEAD OF AN APPROACHING RIDGE. THE SURFACE HIGH WILL KEEP DRIFTING SLOWLY EAST SUNDAY WITH THE RETURN FLOW RESULTING IN A NOTICEABLY WARMER AND MORE HUMID DAY AS COMPARED TO SATURDAY. TEMPERATURES WILL RISE AROUND 10 DEGREES WHILE DEW POINT RISE WILL BE MORE LIKE 20 DEGREES. SOME CLOUDS MAY INCREASE IN THE AFTERNOON AS WARM ADVECTION GETS UNDERWAY ALOFT ALONG THE TAIL END OF A WARM FRONT WHICH WILL MOVE BY TO OUR NORTHWEST...BUT NO PRECIPITATION IS EXPECTED WITH HEIGHTS CONTINUING TO BUILD ALOFT AHEAD OF THE STILL APPROACHING AND BUILDING RIDGE AXIS. CLOUDS WILL MAKE FOR A MUCH MILDER NIGHT ON SUNDAY NIGHT AS THE AFOREMENTIONED WARM FRONT PASSES BY TO THE NORTH...BUT AGAIN NO PRECIPITATION IS EXPECTED. ON MONDAY THE SURFACE HIGH PRESSURE WILL CONTINUE DRIFTING SLOWLY EAST. TEMPERATURES WILL APPROACH OR SLIGHTLY EXCEED 90 DEGREES IN MANY AREAS. DEW POINTS STILL WON`T BE TOO HIGH WITH READINGS PROBABLY STAYING IN THE UPPER 50S IN MUCH OF THE AREA...BUT IT WILL STILL FEEL CONSIDERABLY MORE SUMMER-LIKE THAN IT WILL ON SATURDAY. WITH THE RIDGE STILL BUILDING OVERHEAD...AND DEW POINTS NOT ALL THAT HIGH JUST YET...CONSENSUS APPEARS TO BE FAVORABLE FOR A STORM-FREE DAY SO HAVE KEPT THUNDER OUT OF THE FORECAST. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ECMWF 500 MB RIDGE OVER MID ATLANTIC REGION SLOWLY MOVING TO EAST ALLOWING A SHORT WAVE TO AFFECT THE REGION THURSDAY. MOISTURE AND TEMPERATURES WILL GENERALLY INCREASE ON SOUTHWEST FLOW DURING THE PERIOD. HOT AND HUMID CONDITIONS WILL LEAD TO AN INCREASED CHANCE FOR THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS EACH DAY. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... HIGH CONFIDENCE IN VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. WIND GUSTS /20 KT/ WL SUBSIDE BY 01 OR 02Z. NW WINDS WILL CONT 10-15 KT...EVENTUALLY DIMINISHING TO 5-10KT OVNGT. NO CLDS OF CONSEQUENCE...NOR ANY VSBY RESTRICTIONS. HIGH PRESSURE BUILDS INTO THE REGION SATURDAY. WINDS WL BE A NON- FACTOR...LESS THAN 6 KT...AS THEY TRANSITION FM NLY TO SSWLY. THE HIGH WILL MOVE OFF THE COAST SUNDAY AND MONDAY. WINDS WILL BECOME SOUTHWESTERLY BUT VFR CONDITIONS WILL CONTINUE WITH NO THUNDERSTORMS EXPECTED. THE RISK FOR STORMS WILL INCREASE TUESDAY AFTERNOON AND EVENING AS HOT AND HUMID CONDITIONS INCREASE INSTABILITY. && .MARINE... WINDS HV DIMINISHED BELOW SCA CRITERIA ACROSS ALL WATERS ATTM. HWVR...CDFNT ANALYZED TO BE JUST N OF THE MARINE AREA. CFP FOR THE WATERS WL TRANSPIRE THRU ELY MRNG. PRIND A ZONE OF CAA BHD FNT WL BRING A PD OF FVRBL MIXING SWD. HV OPTED TO DROP THE SCA FOR BALT HARBOR/N OF POOLES ISL/MID-UPR TIDAL PTMC /IT WAS GOING TO EXPIRE AT 11PM ANYWAYS..AND DONT HV EVIDENCE TO EXTEND IT/...BUT LEFT THE REST IN PLACE. AM THINKING THAT IN THE BROADER WATERWAYS THERE IS STILL A DECENT CHC AT MEETING SCA CRITERIA ONCE AGN OVERNIGHT DUE TO THE NLY SURGE. DO NOT HV THE SKILL TO TIME THESE INDIV ELEMENTS OF ABV AND BLO SCA CRIT...SO WL COVER IT WITH ONE HEADLINE. SHUD BE ABLE TO TRIM SCA FOR THE REMAINDER OF THE AREA AOB CURRENT 8AM EXPIRATION. HIPRES MVS OVRHD SAT. WINDS SHUD HV DIMINISHED TO 5-10 KT BY MID MRNG...AND WL CONT IN THAT RANGE THRU THE DAY WHILE BACKING SW. HIGH PRESSURE WILL MOVE OFF THE COAST SUNDAY AND MONDAY WITH A SOUTHERLY FLOW RETURNING. THE HIGH WILL REMAIN OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE PORTION OF NEXT WEEK...ALLOWING FOR THE SOUTHERLY FLOW TO CONTINUE. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS MONDAY THROUGH TUESDAY NIGHT DUE TO THE INCREASING SOUTHERLY FLOW...BUT IT WILL BE MARGINAL DUE TO THE RELATIVELY COOLER WATERS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...FROST ADVISORY UNTIL 8 AM EDT SATURDAY FOR MDZ501. VA...NONE. WV...FROST ADVISORY UNTIL 8 AM EDT SATURDAY FOR WVZ501-503-505. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT SATURDAY FOR ANZ531>534- 537-539>543. && $$ SYNOPSIS...HTS/HAS NEAR TERM...HTS/HAS SHORT TERM...RCM LONG TERM...CEM AVIATION...HTS/HAS/RCM MARINE...HTS/RCM

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