Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 251533 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1133 AM EDT WED MAR 25 2015 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO DRIFT OFF THE ATLANTIC COAST TODAY. A COLD FRONT WILL PASS THROUGH THE AREA LATE THURSDAY INTO FRIDAY. CANADIAN HIGH PRESSURE WILL RETURN FOR FRIDAY INTO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... HEADLINE UPDATE...THE FREEZING RAIN ADVISORY IS CANCELLED. AN UPPER-LEVEL DISTURBANCE IS PASSING BY TO OUR NORTH WHILE HIGH PRESSURE MOVES OFF THE MID-ATLANTIC COAST THIS MORNING. RADIATIONAL COOLING LED TO COLD CONDITIONS EARLY. AS WARM AND MOIST AIR OVERRUNS THIS SURFACE COLD AIR...THIS HAS RESULTED IN RAIN WITH TEMPS NEAR OR BELOW FREEZING. TEMPS WILL CONTINUE TO SLOWLY RISE...CAUSING ANY FREEZING RAIN TO CHANGE TO RAIN BY NOON. A SOUTHERLY FLOW WILL CONTINUE THROUGH THIS AFTERNOON AS HIGH PRESSURE CONTINUES TO SHIFT OFF THE COAST. WARM AND MOIST AIR WILL CONTINUE TO OVERRUN RELATIVELY COOLER AIR IN PLACE...RESULTING IN PLENTY OF CLOUD COVER THIS AFTERNOON. THERE MAY BE SOME RAIN AT TIMES...BUT WITH LITTLE TO NO FORCING MOST OF THE TIME SHOULD TURN OUT DRY AND ANY RAIN THAT DOES FALL WILL BE LIGHT. LOW PRESSURE WILL TRACK THROUGH THE TENNESSEE VALLEY INTO THE OHIO VALLEY TONIGHT WHILE HIGH PRESSURE REMAINS OFF THE COAST. A WARM FRONT WILL APPROACH THE AREA FROM THE SOUTH AS SOUTHERLY WINDS CONTINUE TO OVERRUN THE COOLER AIR IN PLACE...AHEAD OF THIS BOUNDARY. MORE CLOUDS ARE EXPECTED ALONG WITH AREAS OF RAIN. AGAIN...MUCH OF THE TIME WILL TURN OUT DRY AND PRECIPITATION AMOUNTS WILL BE LIGHT. TEMPS WILL BE MUCH MILDER TONIGHT COMPARED TO RECENT NIGHTS DUE TO THE SOUTHERLY FLOW. IN FACT...TEMPS MAY EVEN RISE OVERNIGHT ACROSS THE AREA DUE TO THE SOUTHERLY FLOW. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... A BULK OF THE DAY THU LOOKS RELATIVELY WARM/DRY...ALBEIT W/ A LARGE WAA REGION OVERHEAD DURING THAT TIME. VERY LIGHT AND POORLY ORGANIZED SHOWERS CAN CERTAINLY DEVELOP ANYWHERE IN SUCH A REGION BUT MUCH OF THE ACTIVITY FOR THU MAY ACTUALLY OCCUR EARLY AND AGAIN LATE IN THE DAY. TO START THE DAY...ROUNDING THE OUTER REACHES OF AN OFFSHORE HIGH...SCATTERED SHOWERS WILL SLIDE ACROSS PORTIONS OF THE AREA FROM SW-TO-NE COINCIDENT W/ A LOW LEVEL JET MAX. AS THIS FEATURE GETS BUMPED OFF THE COAST...SOME SINKING AIR...DEPARTING CLOUDS AND WARMING TEMPS SHOULD BE MORE COMMON HEADING INTO THE LATE MRNG/AFTN HRS. MEANWHILE...TWO SEPARATE PIECES OF AN INTENSIFYING AND SYSTEM TO OUR WEST WILL APPROACH FROM THE LOWER OHIO/TENN RVR VLY. THIS FIRST FEATURE WILL BE A LOW PRES SYSTEM SLIDING OVER THE OHIO VLY AND EVENTUALLY OFF TO OUR NORTH...STAYING NORTH AND ALLOWING WARM AIR TO CONTINUE BUILDING INTO THE REGION DURING THE AFTN/EVE. A DEEPENING UPPER WAVE WELL WEST OF THIS ACTIVITY WILL DIVE DOWN FROM THE NRN MS VLY AND STRENGTHEN THE PRECIP ACROSS AREAS JUST AFFECTED BY THE FIRST FEATURE. THIS PIECE OF ENERGY WILL THEN MAKE ITS WAY ACROSS THE APLCNS LATER THAT EVE...NOT EXPECTED TO MOVE ACROSS OUR REGION UNTIL FRI. THE POTENTIAL CONVECTIVE ACTIVITY OUT AHEAD OF THIS DIGGING TROUGH LOOKS TO BE LATE THU NIGHT INTO THE EARLY MRNG HRS FRI. RESIDUAL INSTABILITY MAY BE MARGINAL AT THAT POINT...THOUGH LOW LEVEL STEERING FLOW AND NOCTURNAL JET ACTIVITY MAY MAKE UP FOR IT IN THE WAY OF GUSTY WINDS W/ HEAVIER LOCALIZED DOWNPOURS. WILL KEEP A PERIOD OF LIKELY POPS IN FOR THE OVERNIGHT PERIOD...W/ A SLIGHT REDUCTION IN THE DAYTIME POPS FOR THU. FRI WILL BE ANOTHER USHERING-IN OF CAA W/ DRIER AIR AND OCCASIONALLY BREEZY NW WINDS. A NOTICEABLE TEMP DROP WILL OCCUR FROM THU GOING INTO FRI W/ THE COLD FRONT PASSING THRU...AS TEMPS DROP FROM THE 70S THU AFTN TO THE 40S OVERNIGHT. MAX TEMPS BARELY REACH THE 50 DEG MARK ON FRI...W/ LOWS FRI NIGHT BACK TOWARD THE FREEZING MARK. SOME SCATTERED RAIN SHOWERS AND POSSIBLY SOME BRIEF SNOW MIXING IN W/ THE ISOLATED BATCHES ON FRI W/ THE STRONG PASSAGE OF THE UPPER VORT OVERHEAD. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AN UPPER-LEVEL TROUGH WILL SWING THROUGH THE AREA FRIDAY NIGHT INTO SATURDAY BEFORE COLD HIGH PRESSURE BUILDS OVERHEAD SATURDAY NIGHT INTO SUNDAY. A NORTHWEST FLOW AHEAD OF THE HIGH WILL USHER IN UNUSUALLY COLD CONDITIONS FOR THIS TIME OF YEAR. THE HIGH WILL MOVE OFF THE COAST LATER SUNDAY AND MILDER CONDITIONS ARE EXPECTED IN THE AFTERNOON DUE TO A RETURN FLOW...BUT TEMPS WILL LIKELY REMAIN BELOW CLIMO. A COLD FRONT WILL PASS THROUGH THE AREA MONDAY...BRINGING A CHANCE FOR SHOWERS. MILDER CONDITIONS ARE EXPECTED WITH A SOUTHWEST FLOW AHEAD OF THE FRONT. HIGH PRESSURE WILL RETURN FOR THE MIDDLE PORTION OF NEXT WEEK. && .AVIATION /16Z WEDNESDAY THROUGH SUNDAY/... CIGS WILL DROP TO MVFR LEVELS TODAY INTO THIS EVENING AS WARM AND MOIST AIR OVERRUNS COOLER AIR IN PLACE. IFR CONDITIONS ARE POSSIBLE LATE TONIGHT INTO THURSDAY MORNING. A 40KT LLJ MAY PRODUCE LLWS DURING THIS TIME. CIGS SHOULD LIFT LATER THURSDAY. A COLD FRONT WILL PASS THROUGH THE TERMINALS LATE THURSDAY INTO THURSDAY NIGHT. SHOWERS AND PERHAPS EVEN A THUNDERSTORM ARE EXPECTED DURING THIS TIME. THUNDERSTORMS MAY CONTAIN GUSTY WINDS. VFR CONDITIONS ARE EXPECTED THROUGH THE WEEKEND. && .MARINE... S WINDS EXPECTED ON THE WATERS TODAY. HIGH PRESSURE WILL MOVE OFF THE COAST THIS AFTERNOON AND EVENING AND RETURN FLOW WILL ALLOW WINDS TO INCREASE. A SCA IS IN EFFECT FOR THE BAY NORTH OF DRUM POINT. S WINDS WILL CONTINUE TONIGHT AND GUSTS SHOULD SUBSIDE. SCA CONDS XPCTD THU AHD OF A CD FNT...W/ ISOLD TSTMS PSBL...THEN TURNING TO THE NW AFTR MDNGT THU W/ WINDS CONTINUING ABV SCA VALUES INTO FRI MRNG. HIGH PRESSURE WILL BUILD OVER THE WATERS FOR THE WEEKEND. && .TIDES/COASTAL FLOODING... SOUTHERLY WINDS WILL DEVELOP TODAY AND THE SOUTHERLY FLOW WILL INCREASE AHEAD OF A COLD FRONT THURSDAY. THE INCREASED SOUTHERLY FLOW WILL CAUSE WATER LEVELS TO ELEVATE...AND TIDAL ANOMALIES MAY BE HIGH ENOUGH FOR MINOR FLOODING NEAR TIMES OF HIGH TIDE THURSDAY INTO THURSDAY NIGHT. THE COLD FRONT WILL PASS THROUGH LATER THURSDAY EVENING AND A NORTHWEST FLOW WILL CAUSE WATER LEVELS TO DECREASE LATE THURSDAY NIGHT INTO FRIDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ530>533-538>541. SMALL CRAFT ADVISORY FROM 10 AM TO 6 PM EDT THURSDAY FOR ANZ530>543. && $$ SYNOPSIS... NEAR TERM...BJL/HAS SHORT TERM...GMS LONG TERM...GMS AVIATION...BJL/HAS/GMS MARINE...BJL/HAS/GMS TIDES/COASTAL FLOODING...BJL

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