Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 310747 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 347 AM EDT SUN MAY 31 2015 .SYNOPSIS...
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LOW PRESSURE WILL TRACK UP THE OHIO VALLEY TODAY AND ACROSS SOUTHERN PENNSYLVANIA TONIGHT. A COLD FRONT EXTENDING SOUTH FROM THIS LOW WILL SLOWLY CROSS THE AREA MONDAY INTO EARLY TUESDAY. HIGH PRESSURE IS EXPECTED TO SLIDE INTO THE REGION FOR THE MIDDLE AND LATTER PORTIONS OF THE WEEK.
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&& .NEAR TERM /THROUGH TONIGHT/...
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SFC LOPRES INVOF IND ELY THIS MRNG. ATTENDANT WMFNT EXTENDS INTO NRN NEW ENGLAND...WHILE CDFNT DROPS DOWN INTO TX. SE OF THIS SYSTEM... RDGG REMAINS IN PLACE...AND WL BE THE DOMINANT FEATURE ONCE AGN FOR TDA. THE UPA PTTN REMAINS HIGHLY AMPLIFIED AND BLOCKY...WHICH FAVORS A SLOWER EVOLUTION. THAT HAS BEEN EVIDENCED BY RECENT MDL RUNS. WHILE THE LATEST CYCLE ONCE AGN CONTAINS AN ADJUSTMENT...THERES DECENT OVERALL AGREEMENT IN THE PTTN...WHICH REDUCES THE AMT OF FCST UNCERTAINTY. SFC LOPRES TRAVELS UP THE OHVLY TDA AND ACRS SRN PA TNGT. IT...AND A CPL OF WK S/WVS...WL ASSIST IN LWRG HGTS...MAKING TSRA DVLPMT A LTL EASIER TDA. AHD OF THE FRNTL SYSTEM...AMS REMAINS PLENTY MOIST AND UNSTBL. WHILE NOT THAT GREAT...THE LOW WL ADD A PINCH OF SPD SHEAR NOT TO MENTION DIRECTIONAL SHEAR. THESE ARE THE INGREDIENTS THAT PROMPTED SPC TO PLACE NRN MD IN A SLGT RISK. ELSW...CANT RULE OUT A STRONGER STORM OR TWO...BASED MORE ON LCLZD UTILIZATION OF AVBL ENERGY. WL HV A HVY RA THREAT AS WELL DUE TO PWATS STILL NEAR 1.5 INCHES. LAPSE RATES A LTL BETTER THAN YDA...EXCEEDING 6 C/KM I-95 WWD. AM ONCE AGAIN KEEPING DC-FREDERICKSBURG-SRN MD DRY DURING THE DAYTIME HRS. HWVR...AS THE SFC LOW APPROACHES TNGT...HV ENUF FUEL TO BE ABLE TO GET STORMS TO SPREAD EWD AND HV POPS AREAWIDE... LKLY METRO BALT AND N-CENTRL MD/CHC MOST EVERYWHERE ELSE. GOING ON THE HIGH END OF TEMP GDNC HAS WORKED WELL IN THIS PTTN...AND WL MAINTAIN THAT STRATEGY TDA. FOR THAT MATTER...NEED TO GO A DEGF OR TWO HIER THAN GDNC TO MAINTAIN PERSISTENCE...WHICH IS WHAT WAS DONE FOR THE MAXT FCST. USED MET AS GUIDE FOR MIN-T. DEWPTS WL BE THE LIMITING FACTOR. WHERE RAIN FALLS...WL LKLY GET THERE QUICKER...AND THEN HOLD AS PATCHY FOG DVLPS.
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&& .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
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FRNTL BNDRY WL SLOWLY CROSS THE CWFA MON...SERVING AS A FOCUS FOR MULT ROUNDS OF SHRA/TSRA. WL BE ON THE WARM/MOIST SIDE OF THE BNDRY...SO PDS OF HVY RAFL WL BE A PRIMARY CONCERN. THE BNDRY WL ALSO SERVE AS A SOURCE OF CNVGNC...MAKING FULL USE OF ANY UNSPENT INSTBY. BELIEVE THAT THERE STILL CUD BE SOME STRONGER STORMS AFTER BRIEF SPLASHES OF INSOLATION. WL CARRY WIND AND RAIN THREATS IN HWO. GIVEN AVBL FORCING AND DIURNAL HEATING...HV BUMPED UP POPS INTO LKLY/CAT RANGE MON...AND CARRIED THAT INTO I-95 FOR MON EVE. THINK ACTIVITY WL BECOME A LTL LESS WIDESPREAD OVNGT MON...BUT AM NOT CONFIDENT THAT IT/LL CEASE OUTRIGHT. THEREFORE WL BE CARRYING CHC POPS THRU THE OVNGT HRS. SINCE AMS WL BE ABOUT THE SAME...AM CONTG THE NEAR TERM TEMP FCSTG STRATEGY INTO DAY 2. ONLY COMPLICATING FACTOR WL BE IMPACT FM NMRS SHRA/TSRA. NONETHELESS...MAXT FOR MON WAS RAISED BY SEVRL DEGF... INTO THE 80S. MAY EVEN SEE UPR 80S NEAR EZF/SRN MD. SHUD HV SLGTLY COOLER/DRIER AIR ADVECTING EWD BY MON NGT...AND MIN-T NOT QUITE AS MUGGY.
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&& .LONG TERM /TUESDAY THROUGH SATURDAY/...
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AN UPPER LEVEL CUT-OFF LOW WILL SPIN ACROSS THE GULF COAST STATES THROUGH MID-WEEK WHILE LOW PRESSURE RIDES ALONG A QUASI-STATIONARY BOUNDARY ACROSS THE MID-ATLANTIC TUESDAY. A PLUME OF HIGH PWATS WILL CONTINUE TO RIDE ALONG THE BOUNDARY AND LEAD TO CLOUDS AND SHOWERS TUESDAY. A TEMP CONTRAST BETWEEN THE NW AND SE WILL LIKELY OCCUR DUE TO COOLER AIR MOVING IN ON THE BACKSIDE OF THE THE FRONTAL BOUNDARY TUESDAY. TEMPS WILL RANGE FROM THE LOW 70S TO THE UPPER 70S. INSTABILITY WILL INCREASE ON THE WARM SIDE OF THE BOUNDARY AND THUNDERSTORMS WILL BE POSSIBLE. MAIN IMPACT WILL BE HEAVY RAIN FROM STORMS AND DEPENDING ON HOW MUCH RAIN THE AREA RECEIVES SUN AND MON...LOCALIZED FLOODING IS POSSIBLE. RAINFALL AMTS OF 0.5-1.5 INCHES POSSIBLE TUESDAY INTO WEDNESDAY. SLOW MOVEMENT OF THE FRONT WILL OCCUR TUESDAY NIGHT AND SHOWERS WILL LIKELY CONTINUE AS THE UPPER LEVEL PATTERN REMAINS LOCKED. NRLY WIND WILL EVENTUALLY SPREAD THE ENTIRE MID-ATLANTIC BY WEDNESDAY NIGHT AS HIGH PRESSURE MOVES INTO THE REGION. SHOWERS SHOULD END ACROSS THE REGION WEDNESDAY. TEMPS WILL REACH THE LOW TO MID 70S WEDNESDAY. HIGH PRESSURE WILL WEDGE DOWN INTO THE REGION WEDNESDAY AND THURSDAY BEFORE MOVING OFF THE COAST FRIDAY. SHOWERS AND THUNDERSTORMS RETURN TO THE FORECAST FRIDAY-SATURDAY AS DISTURBANCES MOVE INTO THE REGION.
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&& .AVIATION /08Z SUNDAY THROUGH THURSDAY/...
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VFR HAS BEEN MORE WIDESPREAD THAN ORIG FCST...DUE IN PART TO PDS OF CLDS. HWVR...SKIES MOCLR ATTM. HV SEEN A FEW SPOTS DROP VSBYS QUICKLY ONLY TO RECOVER. MRB SUFFERING FM VSBY RESTRICTIONS ATTM. AM CARRYING LWR END IN A TEMPO GROUP...STILL BELIEVING THAT RECOVERY IS PSBL. WL NOT BE CARRYING RESTRICTIONS ELSW THRU SUNRISE. ANY FOG WL DSPT AFTER THAT POINT. SCT TSRA WL BE DVLPG ONCE AGN TDA DUE TO DAYTIME HEATING FM THE SUN. CVRG LKLY WL BE IMPROVING INTO ELY EVNG AS BETTER SUPPORT ARRIVES. HV REDUCED CONFIDENCE IN SPECIFIC TIMING/PLACEMENT...BUT MRB ONCE AGN STANDS THE BEST CHC AT SEEING TSRA. THAT THE ONLY PLACE WHERE ANY WEATHER OUTRIGHT MENTIONED. CHO/IAD HV A MORE LIMITED CHC... WHICH DROPS FURTHER TWD DCA/BWI. THIS FCST LKLY TO BE REFINED THRUT THE DAY. ADDITIONAL COMMENTS WL BE ADDED TO TAFS ONCE CONFIDENCE SUFFICIENT. BRIEF IFR RESTRICTIONS PSBL W/IN ANY STORM. JUST LIKE PAST SVRL DAYS...CVRG OF AFTN-EVE STORMS WL DICTATE WHEN/WHERE/HOW MUCH FOG WL DVLP OVNGT. AS A START HV MVFR IN CLIMO FVRD AREAS ATTM. AS A CDFNT APPROACHES...CVRG OF TSRA WL BE MORE NMRS TO EVEN WIDESPREAD MON...SPCLY DURING THE AFTN-EVE HRS. MORE FREQUENT FLGT RESTRICTIONS WL BE PSBL...BUT STILL BELIEVE THAT THERE WL BE INTERVALS OF VFR DURING THE DAY. HWVR...CIGS LKLY TO LWR IN THE EVNG. SUB-VFR CIGS POSSIBLE TUESDAY INTO WEDNESDAY AS SHRA VCTS CONTINUES. HEAVY RAIN MAY LEAD TO REDUCED VSBYS DURING THIS TIME. WINDS BECOME NRLY FROM N TO S TUESDAY INTO WEDNESDAY.
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&& .MARINE...
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SLY CHANNELING CONTS ACRS THE BAY AND ITS TRIBS/INLETS. XTNDD SCA THRU 6AM BASED ON RECENT OBS. WRF OUTPUT SUGGESTS THAT WINDS WL DECLINE THRU THE ELY MRNG HRS...AND MAY BE ABLE TO PULL THE PLUG AN HR OR TWO ERLR. INDEED THAT LATEST MAROBS BACK THAT UP. SLY FLOW WL CONT ACRS THE WATERS TDA-TNGT...AND MIXING WL RESUME AFTER DAYBREAK. BELIEVE THAT THE SCA FOR THE BAY/LWR PTMC STILL IN GOOD SHAPE...AND WL NOT TOUCH IT. IN ADDITION...A TSRA THREAT WL INCREASE TNGT...MAKING FOR A FEW MARINE WRNGS PSBL INVOF STRONGER STORMS. CDFNT ARRIVES MON-MON NGT. SHRA/TSRA WL BE MORE NMRS...AND SOME MAY CONTAIN GUSTY WINDS. VERT TRANSFER WL BE LESS FVRBL DUE TO ATMOSPHERIC MSTR...AND THEREFORE WL NOT BE RAISING ANOTHER SCA FOR THE PM HRS. HWVR...ANOTHER AFTN-EVE OF MARINE WRNGS PSBL. WINDS BECOME NRLY ON THE WATERS TUESDAY INTO WEDNESDAY BUT SHOULD STAY BELOW SCA CRITERIA. SHOWERS EXPECTED TUESDAY AND WEDNESDAY WITH A CHANCE OF THUNDERSTORMS. SOME SHOWERS MAY BE HEAVY AND REDUCE VSBYS.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR ANZ530>534-537>543. SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 2 AM EDT MONDAY FOR ANZ530>534-537>543.
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&& $$ SYNOPSIS...HTS NEAR TERM...HTS SHORT TERM...HTS LONG TERM...HAS AVIATION...HTS/HAS MARINE...HTS/HAS

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