Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 181350 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 950 AM EDT MON MAY 18 2015 .SYNOPSIS... HIGH PRESSURE IS POSITIONED OFF THE SOUTHEAST COAST. A WEAK COLD FRONT OVER PENNSYLVANIA WILL APPROACH THE MID ATLANTIC TODAY. A STRONGER COLD FRONT WILL MOVE IN FROM THE WEST TUESDAY. COOLER AND DRY HIGH PRESSURE WILL FOLLOW FROM THE MIDWEEK UNTIL THE EARLY PART OF THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WEAK SFC BOUNDARY STILL SITTING ACROSS ERN PA AND NJ...NOT MAKING ANY PROGRESS IN ANY DIRECTION. CLOSER TO HOME...THE HOT AND HUMID AIRMASS REMAINS...WITH DEWPOINTS AROUND OR ABOVE 70 AND TEMPS ALREADY PUSHING 80 WHERE THERE HAS BEEN MORE SUNSHINE. CONVECTIVE TEMP OFF THE 12Z SOUNDINGS IS 83-84 DEGREES...A TEMP THAT WILL EASILY BE EXCEEDED IN MOST AREAS. MODEL SOUNDINGS SHOW ABOUT 1000 J/KG OF CAPE THIS AFTERNOON WITH VIRTUALLY ZERO SHEAR. MODEL PWATS JUMP OVER 1.75 INCHES...WHICH IS NEAR MAXIMUM FOR THIS TIME OF YEAR. THESE PARAMETERS LEND THEMSELVES TO A POTENTIAL FOR HEAVY RAIN BUT NOT PARTICULARLY SEVERE WEATHER. THE GOOD NEWS WITH RESPECT TO FLOOD POTENTIAL IS THAT IT HAS BEEN FAIRLY DRY AND FFG IS QUITE HIGH...ESPECIALLY IN THE NORTHERN HALF OF OUR FORECAST AREA. WILL KEEP AN EYE OUT BUT NO NEED FOR A FLOOD WATCH. NO SIGNIFICANT CHANGES TO THE FORECAST FOR TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... SHOWERS AND A COUPLE OF THUNDERSTORMS WILL AFFECT THE REGION MAINLY THIS EVENING WHILE THE BACKDOOR BNDRY WASHES OUT. A WARM NGT W/ LOWS IN MOST OF THE AREA IN THE 60S...L70S IN THE CITIES. A CD FNT XTNDG FM MN TO KS WILL MOVE INTO THE MID ATLC DURG THE 1ST HALF OF TUE GENERATING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS BEFORE COOLER AND DRIER AIR PUSHES INTO THE REGION TUESDAY NIGHT. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... RETURN TO MORE SPRING-LIKE WX WED WITH MUCH DRIER/COOLER AIR MOVING INTO AREA. LOW TEMPS WED MORNING WILL BE MAINLY IN 50S...EXCEPT IN METRO AREAS (L60S). MAX TEMPS WED ALSO VERY NICE...WITH M60S WEST...U60S/L70S CENTRAL...AND M70S SOUTHEAST PARTS OF CWA UNDER MOSTLY SUNNY SKIES. ONLY WX CONCERNS WED WOULD BE GUSTY WINDS POSSIBLE NEAR BAY THROUGH MOST OF THE DAY. 00Z MODEL GUIDANCE INCONSISTENT WITH REGARDS TO POTENTIAL WEAK SFC LP MOVING TO OUR SOUTH LATE WED OR THU. PRECIP SIGNAL GENERALLY A RESULT OF LIFT FROM FAVORABLE LOCATION OF RRQ OF UPPER JET. 00Z NAM MOST AGGRESSIVE WITH QPF TOTALS...BUT BELIEVE NAM IS LIKELY OVERDONE DUE TO LIMITED MOISTURE AND UNFAVORABLE TRACK OF SFC LP. FOR NOW...KEPT POPS LOW WITH ONLY SLT CHC FOR SHOWERS NORTH AND CHC SOUTH. THINGS QUIET DOWN AGAIN AFTER THU...WITH A SLOW WARMING TREND AND A DRY FORECAST THROUGH THE WEEKEND AS HP SETTLES INTO THE REGION. BY SUN RETURN FLOW WILL HELP PUSH TEMPS BACK INTO THE U70S/L80S...WITH LOW TEMPS SUNDAY NIGHT INTO THE 60S DUE TO INCREASING MOISTURE. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... SHRA/TSRA DEVELOP THIS AFTERNOON AND COULD AFFECT ALL TERMINALS. CIGS SHOULD REMAIN VFR BUT HEAVY RAIN COULD DROP VSBYS. FOR NOW THIS IS NOT MENTIONED IN TAFS. WILL REASSESS FOR 18Z ISSUANCE. MODELS ARE NOT BULLISH ON FOG POTENTIAL TONIGHT...BUT WHERE IT RAINS THE POTENTIAL DOES EXIST. RW/TRW WL AGN BE PSBL TUE...MOSTLY DURG LATE MRNG AND AFTN. VFR CONDITIONS WEDNESDAY. LOW CHC FOR IFR CONDS IF SHWRS DEVELOP THU...WITH BEST CHCS AT CHO. && .MARINE... WINDS SHOULD REMAIN BELOW SCA CRITERIA TODAY. SHOWERS AND THUNDERSTORMS WILL IMPACT THE WATERS WHICH MAY REQUIRE THE ISSUANCE OF SMWS THIS AFTERNOON AND EVENING. NO MARINE HAZARDS MONDAY NIGHT THROUGH TUESDAY. SMALL CRAFT ADVISORY CONDITIONS POSSIBLE TUE NGT THROUGH WED AFTERNOON. NO MARINE CONCERNS THU. && .CLIMATE... IAD TIED A RECORD HIGH MIN TEMP YDA. UNUSUALLY WARM WEATHER IS FORECAST THE NEXT FEW NIGHTS. BELOW IS A LIST OF RECORD HIGH MINIMUM TEMPERATURES FOR MAY 18TH AND 19TH. SITE...MAY 18TH.........MAY 19TH......... DCA....68 (1995*).......70 (1986/1962)... BWI....68 (1900/1896)...75 (1877)........ IAD....66 (1995)........66 (1969)........ *ALSO IN 1953...1943 AND 1900. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...ABW NEAR TERM...JE SHORT TERM...ABW LONG TERM...MSE/ABW AVIATION...JE/MSE/ABW MARINE...MSE/ABW CLIMATE...ABW

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