Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 251450 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1050 AM EDT SAT APR 25 2015 .SYNOPSIS... LOW PRESSURE OVER MISSOURI WILL TRACK EAST TODAY AND PASS TO THE SOUTH OF THE AREA TONIGHT INTO SUNDAY. AN UPPER-LEVEL TROUGH OF LOW PRESSURE EXTENDING FROM MAINE DOWN THE EASTERN SEABOARD WILL TRACK SLOWLY SOUTH MONDAY. HIGH PRESSURE WILL RETURN TUESDAY. LOW PRESSURE MAY IMPACT THE REGION THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... EARLY THIS MORNING...WE RECEIVED A FEW REPORTS OF SLEET AND SNOW ACROSS NORTHERN MARYLAND THIS MORNING...EVEN AS FAR SOUTH AS SOUTHERN BALTIMORE CITY. SOCIAL MEDIA SHOWED ONE CAR WITH A THIN COATING OF SNOW THAT FELL IN THE TOWN OF LITTLE ORLEANS IN EASTERN ALLEGANY COUNTY MD. EVEN HAD A FEW SPOTTER REPORTS OF SLEET WITH NO ACCUM OVER RAPPAHANNOCK IN NORTH CENTRAL VIRGINIA. THE 12Z IAD SOUNDING HAD SUB-FREEZING TEMPS ABOVE 850 HPA AND WITH DRY SURFACE AIR...WEB BULB COOLING IS KEEP THE COLUMN ALMOST BELOW FREEZING DOWN TO THE SURFACE...WHICH EXPLAINS A FEW RPTS OF SLEET. RADAR TRENDS SHOW ADVANCE OF NORTHERN EDGE OF THE FIRST WAVE OF LIGHT PRECIP AT 1430Z EXTENDING FROM GRANT/HARDY COUNTIES IN WV SOUTHEAST ACROSS N-CENTRAL VA AND INTO LOWER SRN MD. PRECIP IS VERY LIGHT...AND THERE COULD BE A LITTLE SLEET MIXED IN AT ONSET. BASED ON RADAR...ADVANCED UP THE TIMING OF PRECIP SLIGHTLY FOR THIS AFTERNOON. 12Z NAM MODEL SEEMS IN LINE WITH CURRENT FORECAST IN TERMS OF TIMING AND NOT MUCH ADJUSTMENT MADE TO GOING FORECAST FOR TIMING/AMOUNT OF PRECIP FOR THIS EVENT. HEAVIEST AMOUNTS WILL OCCUR OVER THE SW PORTION OF OUR CWA. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... TONIGHT...STATIONARY FRONT RETURNS SOUTH AS A COLD FRONT AFTER MIDNIGHT. PRECIP SHIFTS SOUTH ALONG WITH IT...WITH LIKELIES LIMITED TO THE SRN THIRD OF THE CWA FOR SUNDAY MORNING. STORM TOTAL QPF QUARTER TO HALF INCH FOR SRN TWO THIRDS OF CWA...TENTH INCH OR SO FOR NERN MD. MIN TEMPS LOW TO MID 40S. SUNDAY...NORTH WINDS AND SOMEWHAT CLEARING SKIES FROM NORTH TO SOUTH THROUGH THE DAY. JUST LOW CHANCE POPS FOR SRN ZONES FOR THE AFTERNOON. WITH A LITTLE DRIER FORECAST...RAISED MAX TEMPS TO LOW 60S FOR MUCH OF THE AREA...A DEGREE ABOVE MAV/MET/GMOS BLEND. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... AVG HIGH TEMPS IN LATE MAR ARE A70...LOWS M40S. IN THE XTND 70 IS PRBLY THE BEST WE CAN HOPE FOR...AND LOWS SHOULD BE RIGHT ARND NRML. HV INCRSD THE CLD CVR CWA-WIDE/INTRODUCED RW INTO THE FCST MON FOR THE NRN/ERN PART OF CWA. VERTICALLY STACKED LOW WL BE SPINNING IN THE GULF OF ME...AND A SHARPENING TROF WL WORK ITS WAY SWD DOWN THE E CST INTO THE MID ALTC MON. BLO NRML HIGHS XPCTD - GNRLY IN THE U50S...PSBLY M60S IN THE CENTRAL SHEN VLLY. WK INDUCED HIGH OVR THE AREA TUE/WED WL ALLOW FOR MORE SUNSHINE AND TEMPS TO REBOUND BACK INTO M60S. AN AREA OF LOW PRES IS XPCTD TO DVLP OVR THE GULF STATES THU...CAUSING INCRSG CLDS IN THE MID ATLC ALONG W/ A CHC OF RAIN. THIS LOW IS XPCTD TO TRACK NE AND COMBINE W/ A SHORT WV DESCENDING FM QUEBEC...FORMING ANOTHER GULF OF ME LOW. THIS ONE IS XPCTD TO FORM TOO FAR OUT TO SEA TO HV ANY IMPACT ON THE MID ATLC OUTSIDE OF KEEPING THE AREA IN COOL NRLY FLOW. THE WEEK SHOULD CLOSE OUT UNDER HIGH PRES. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... EXPECT VFR CONDITIONS THROUGH THROUGH MID TO LATE DAY. PRECIP WILL MOVE IN AND CIGS WILL LOWER. THIS EVENING EXPECT MVFR TO LOCALLY IFR CIGS IN PRECIP...EXPECT BWI/IAD/DCA CIGS TO RANGE FROM 2-3 KFT THIS EVENING...LOCALLY DOWN TO 1KFT IN HEAVIER PRECIP. OVERNIGHT...BWI AND IAD COULD SEE CIGS BLO 1KFT. WINDS WILL BE UNDER 10 KTS THROUGH THE PERIOD. RW/PTNL MVFR CIGS PSBL MON...THEN NO PROBS XPCTD TUE/WED. && .MARINE... WINDS EXPECTED TO BE BELOW 10 KTS ACROSS THE WATERS TODAY AND VARIABLE IN DIRECTION. RAIN WILL OVERSPREAD THE WATERS THIS AFTERNOON INTO THIS EVENING A FRONT STALLS TONIGHT WITH NORTH WINDS SUNDAY AS THE FRONT RETURNS SOUTH AS A COLD FRONT. NORTHERLY CHANNELING POSSIBLE ON SUNDAY AFTERNOON. SCA CONDS WL BE LKLY MON AFTR A CD FNT MOVES THRU THE WATERS AND THE PRES GRAD TIGHTENS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...SMZ NEAR TERM...SMZ SHORT TERM...BAJ LONG TERM...ABW AVIATION...SMZ MARINE...SMZ

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