Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 221914 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 314 PM EDT SUN MAR 22 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVERHEAD THROUGH TUESDAY BEFORE MOVING OFF THE COAST WEDNESDAY. A COLD FRONT WILL CROSS THE AREA THURSDAY. CANADIAN HIGH PRESSURE WILL RETURN FOR FRIDAY INTO THE WEEKEND. HIGH PRESSURE WILL RETURN FOR LATE IN THE WEEK. && .NEAR TERM /THROUGH MONDAY/... THE MID-ATLANTIC IS LARGELY UNDER THE INFLUENCE OF HIGH PRESSURE SPRAWLING SOUTH FROM CENTRAL THIS AFTERNOON. THE CENTER OF THE HIGH WILL SLIDE TO A POSITION NE OF MI BY MONDAY AFTERNOON. MEANWHILE LOW PRESSURE WILL TRACK ALONG THE GULF COAST AND OFFSHORE MONDAY. DRIER AIR IS ADVECTING IN ON BREEZY N/NW WINDS THIS AFTERNOON. THE GUSTS SHOULD SUBSIDE THIS EVENING. A MIXTURE OF MID AND HIGH LEVEL CLOUDS WILL TRAVERSE THE AREA TONIGHT...BUT NOT REALLY A DEFINITIVE PERIOD OF OVC OR CLR...AND THICKER CLOUDS ARE MORE LIKELY TO THE SOUTH CLOSER TO THE LOW PRESSURE SYSTEM AND AIDED BY AN ONSHORE WIND COMPONENT. AN INVERTED SFC TROF WILL EXTEND NORTHWARD FROM THE LOW TONIGHT AS A WEAK MID LEVEL SHORT WAVE TROUGH APPROACHES...AND SOME MODELS PRINT VERY LIGHT QPF AS FAR NORTH AS THE CENTRAL BLUE RIDGE/SRN SHEN VALLEY. HOWEVER THINK DRY AIR WILL WIN OUT. LOWS SHOULD DROP WELL INTO THE 20S ACROSS THE NRN HALF OF THE AREA...WHILE THE CLOUDS MAY HOLD TEMPS NEAR THE FREEZING MARK IN THE SOUTH. THE HIGH WILL WEDGE DOWN THE E SIDE OF THE MONDAY. COMBINED WITH CAA AND POSSIBLY THICKER CLOUDINESS AT TIMES...HIGH TEMPS WILL BE LOWER THAN TODAY...GENERALLY IN THE 40S TO AROUND 50. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... HIGH PRESSURE WILL REMAIN CENTERED OVER NEW ENGLAND MONDAY NIGHT WHILE AN UPPER-LEVEL DISTURBANCE IN THE NORTHERN STREAM OF THE JET PASSES BY TO OUR NORTH. THIS WILL BACK THE LOW-LEVEL FLOW TO THE SOUTHWEST...CAUSING OVERRUNNING TO TAKE PLACE. HOWEVER...LITTLE MOISTURE WILL BE IN PLACE AND THE LIFT ASSOCIATED WITH THE UPPER- LEVEL DISTURBANCE IS EXPECTED TO STAY TO THE NORTH. THEREFORE...ANY PRECIPITATION THAT DOES OCCUR WILL BE LIGHT AND MOST AREAS MAY ACTUALLY END UP DRY. HOWEVER...ANY PRECIPITATION THAT DOES FALL WOULD BE IN THE FORM OF SNOW. DID ADD THE CHANCE/SLIGHT CHANCE FOR SNOW SHOWERS AND FLURRIES INTO THE FORECAST...BUT LITTLE OR NO SNOW ACCUMULATION IS EXPECTED. WILL CONTINUE TO KEEP AN EYE ON THE FORECAST...SHOULD THE DISTURBANCE TRACK FARTHER SOUTH OR OVERRUNNING IS DEEPER THAN EXPECTED...THEN A PERIOD OF SNOW WITH LIGHT ACCUMULATION WOULD AFFECT THE AREA. MIN TEMPS WILL BE BELOW CLIMO DUE TO THE COLD HIGH PRESSURE TO OUR NORTH. MIN TEMPS WILL RANGE FROM THE LOWER TO MIDDLE 20S IN THE MOUNTAINS TO THE LOWER 30S IN WASHINGTON AND BALTIMORE. THE UPPER-LEVEL DISTURBANCE WILL MOVE AWAY FROM THE AREA TUESDAY AND THE HIGH WILL REMAIN ENTRENCHED OVER NEW ENGLAND. THEREFORE...MORE DRY CONDITIONS ARE EXPECTED WITH TEMPS REMAINING BELOW CLIMO. THERE WILL BE A BKN/OVC DECK OF MID-LEVEL CLOUDS ACROSS THE SOUTHERN AND WESTERN PORTIONS OF THE CWA...BUT CLOUDS SHOULD GIVE WAY TO MORE SUNSHINE ACROSS NORTHERN AND EASTERN PARTS AS DRIER AIR WORKS ITS WAY IN BEHIND THE DEPARTING DISTURBANCE. THE HIGH WILL MOVE OFFSHORE TUESDAY NIGHT THROUGH WEDNESDAY. LOW PRESSURE WILL TRACK THROUGH THE GREAT LAKES DURING THIS TIME. A SOUTHERLY FLOW WILL INCREASE...CAUSING MORE OVERRUNNING. HOWEVER...THE DEEP MOISTURE IS STILL EXPECTED TO REMAIN TO OUR SOUTH WHILE THE LIFT WILL REMAIN WELL TO OUR NORTH CLOSER TO THE LOW OVER THE GREAT LAKES. THEREFORE...MORE CLOUDS ARE EXPECTED AND THERE IS A CHANCE FOR RAIN...BUT MOST OF THE TIME SHOULD TURN OUT DRY AND ANY RAIN THAT DOES OCCUR WILL BE LIGHT. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE OFFSHORE WILL INTERACT WITH LOW PRESSURE OVER THE EASTERN GREAT LAKES WEDNESDAY NIGHT TO ALLOW FOR A PERSISTENT SOUTHERLY FLOW AND A CHANCE FOR LIGHT RAIN. TEMPERATURES WILL BE NEARLY 10 TO 15 DEGREES ABOVE NORMAL WEDNESDAY NIGHT. A SECOND AREA OF LOW PRESSURE WILL DEVELOP OVER THE GREAT LAKES THURSDAY ALONG A FRONT EXTENDING FROM THE FIRST LOW. AN INCREASED SOUTH TO SOUTHWEST FLOW WILL DEVELOP AHEAD OF AN ASSOCIATED COLD FRONT WITH THE SECOND LOW AND HELP TO FUEL THE CHANCE OF RAIN SHOWERS OR PERHAPS A THUNDERSTORM OR TWO. THE COLD FRONT SHOULD PASS THROUGH THE REGION MIDDAY THURSDAY INTO THURSDAY EVENING BEFORE MAKING ITS WAY TO THE EAST COAST THURSDAY NIGHT. TEMPERATURES THURSDAY AND THURSDAY NIGHT WILL BE ABOVE NORMAL. A TRAILING UPPER LEVEL TROUGH OF LOW PRESSURE COULD SPAWN A COUPLE OF RAIN SHOWERS FRIDAY AND PERHAPS A RAIN OR FEW SNOW SHOWERS MIX FRIDAY NIGHT. TEMPERATURES WILL BECOME NOTICEABLY COLDER FRIDAY AND FRIDAY NIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION SATURDAY THROUGH SUNDAY...ALLOWING FOR INCREASED AMOUNTS OF SUNSHINE EACH DAY BUT IN CONTRAST...BELOW TO WELL BELOW NORMAL TEMPERATURES WITH HIGHS ONLY REACHING THE MIDDLE 40S SATURDAY. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... MOSTLY A WIND FORECAST FOR THE TERMINALS WITH HIGH PRESSURE SITUATED TO THE NORTH THROUGH TONIGHT AND MONDAY. VFR THROUGH THE PERIOD...WITH MID/HIGH LEVEL CIGS POSSIBLE AT TIMES. WINDS N/NW AND GUSTING TO AROUND 20 KT THROUGH THIS AFTERNOON EXCEPT E AND LIGHTER AT CHO. SAME GENERAL WIND DIRECTION PREVAILS THROUGH THE PERIOD BUT WITH LIGHTER WINDS TONIGHT AND EARLY MONDAY. WINDS BECOME MORE NE MONDAY AFTERNOON. VFR CONDITIONS ARE EXPECTED MOST OF THE TIME MONDAY NIGHT THROUGH WEDNESDAY. A FEW FLURRIES ARE POSSIBLE LATE MONDAY NIGHT INTO TUESDAY MORNING...BUT MOST PLACES SHOULD BE DRY. WINDS SHOULD BE LIGHT THROUGH TUESDAY NIGHT. SOUTHERLY WINDS WILL INCREASE WEDNESDAY WITH GUSTS AROUND 20 KNOTS POSSIBLE. IFR OR PERHAPS LIFR CONDITIONS POSSIBLE WEDNESDAY NIGHT INTO THURSDAY MORNING WITH LOW CEILINGS AND REDUCED VISIBILITY DUE TO STRATUS...PATCHY FOG OR PERHAPS A RAIN SHOWER. WIND SOUTH TO SOUTHWEST AROUND 5 KNOTS. MVFR CONDITIONS...MAINLY...THURSDAY AFTERNOON WITH A CHANCE OF RAIN SHOWERS OR A THUNDERSTORM NEAR ANY OF THE TERMINALS. WIND SOUTHWEST BECOMING WEST 5 TO 10 KNOTS WITH HIGHER GUSTS. WIND COULD GUST OVER 20 KNOTS AT TIMES IN GUSTY SHOWERS. && .MARINE... OCCASIONAL NW WIND GUSTS TO 20 KT SHOULD SUBSIDE BY LATE THIS AFTERNOON AS MIXING DECREASES. HOWEVER A SURGE OF HIGHER PRESSURE LATE TONIGHT WILL ONCE AGAIN RAISE THE POTENTIAL FOR SOME 20 KT GUSTS TONIGHT THROUGH MONDAY MORNING...MAINLY OVER THE BAY WHERE N WINDS CAN CHANNEL. WINDS WILL SUBSIDE MONDAY AFTERNOON AS THE GRADIENT SUBSIDES...BUT AN EXTENSION OF THE SCA WAS WARRANTED AS SOME GUSTS WILL REMAIN POSSIBLE AS MIXING INCREASES MONDAY MORNING. HIGH PRESSURE WILL BUILD OVER THE WATERS MONDAY NIGHT AND TUESDAY BEFORE MOVING OFF THE COAST WEDNESDAY. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS ON WEDNESDAY. SMALL CRAFT ADVISORY CONDITIONS POSSIBLE WEDNESDAY NIGHT INTO THURSDAY AS SOUTH TO SOUTHWESTERLY WINDS INCREASE OVER THE CHESAPEAKE BAY AHEAD OF AN APPROACHING COLD FRONT. WINDS 10 TO 15 KNOTS WITH GUSTS 20 TO 25 KNOTS POSSIBLE. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ530>543. SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 1 PM EDT MONDAY FOR ANZ530>534-537-539>541-543. && $$ SYNOPSIS...BJL NEAR TERM...ADS SHORT TERM...BJL LONG TERM...KLW AVIATION...BJL/ADS/KLW MARINE...BJL/ADS/KLW

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