Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 010915 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 415 AM EST SUN MAR 1 2015 .SYNOPSIS...
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HIGH PRESSURE WILL MOVE EAST EARLY TODAY AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE WEST. MOISTURE WILL OVERSPREAD THE REGION TODAY CREATING A WINTRY MIX. A COLD FRONT WILL CROSS THE AREA TONIGHT. HIGH PRESSURE BUILDS ON MONDAY AND CONTINUES THROUGH TUESDAY. A WARM FRONT WILL CROSS THE AREA TUESDAY NIGHT. THEN A STRONG COLD FRONT WILL CROSS THE REGION LATE WEDNESDAY AS COLD HIGH PRESSURE BUILDS IN FOR THURSDAY AND CONTINUES INTO THE WEEKEND.
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&& .NEAR TERM /THROUGH TONIGHT/...
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A WINTER STORM WARNING IS IN EFFECT FOR PORTIONS OF NORTHEAST MARYLAND TODAY AND TONIGHT. WINTER WEATHER ADVISORIES ARE IN EFFECT ACROSS THE MID-ATLANTIC TODAY AND TONIGHT. A 1040MB HIGH IS CENTERED ACROSS THE I-95 CORRIDOR FROM NEW ENGLAND TO RICHMOND THIS MORNING. TEMPERATURES ARE IN THE 20S WITH DEWPTS IN THE SINGLE DIGITS/TEENS ACROSS THE AREA. A SHORTWAVE TROUGH IS LOCATED ACROSS SOUTHERN LAKE MICHIGAN THIS MORNING WHILE A JET STREAK INTENSIFIES ACROSS THE MID-WEST. CONFLUENT FLOW AT 850MB HAS LED TO WARM AIR ADVECTION AND PRECIPITATION HAS BROKEN OUT FROM THE MISSISSIPPI VALLEY TO THE OHIO VALLEY. A SECONDARY LOW LEVEL JET ACROSS THE CAROLINAS HAS ALSO LED TO OVERRUNNING. THESE TWO LOW LEVEL JETS HAVE LED TO GULF AND ATLANTIC MOISTURE TO STREAM INTO THE REGION THIS MORNING. SNOW IS EXPECTED TO MOVE INTO THE POTOMAC HIGHLANDS THIS MORNING ASSOCIATED WITH THE MOISTURE ACROSS THE OHIO VALLEY. SNOW WILL ALSO MOVE INTO THE CENTRAL FOOTHILLS AND PIEDMONT AS WELL THIS MORNING ASSOCIATED WITH THE WWA ACROSS THE CAROLINAS. SNOW WILL EVENTUALLY SPREAD TO THE NORTH AND EAST AND REACH IAD-DCA-BWI BY MID-LATE MORNING. WARM AIR ALOFT WILL BEGIN TO NOSE INTO THE REGION FROM THE SOUTHWEST LATE THIS MORNING AND SLEET AND FREEZING RAIN ARE EXPECTED BY LATE MORNING ACROSS THE SOUTHWEST TO EARLY AFTERNOON ACROSS NE MARYLAND. TEMPS WILL SLOWLY CLIMB TODAY BUT MAINLY STAY BELOW FREEZING SO SNOW AND ICE ARE EXPECTED TO ACCUMULATE. THE CHANGEOVER FROM SNOW TO SLEET/FZRA IS EXPECTED TO OCCUR QUICKLY AND THEREFORE SNOW AMOUNTS WERE TAKEN DOWN SLIGHTLY. THIS EVENT IS EXPECTED TO BE MORE OF A ICING EVENT THAN A SNOW EVENT. A WINTER STORM WARNING WAS ISSUED FOR NORTHEAST MARYLAND DUE TO THE POTENTIAL FOR HEAVY ICING DUE TO HIGHER AMTS OF LIQUID EXPECTED IN THIS AREA AND SUB FREEZING TEMPERATURES THROUGH THE DAY. THIS REGION IS CLIMATOLOGICAL KNOWN TO STAY COLDER IN COLD AIR DAMMING SITUATIONS. FURTHER WEST AND SOUTH...WINTER WEATHER ADVISORIES ARE IN EFFECT FOR AROUND A TENTH OF AN INCH OF ICE TO ONE TO TWO TENTHS ACROSS THE N AND W SUBURBS OF DC AND BALTIMORE. FREEZING RAIN WILL END FROM SW TO NE LATE THIS AFTERNOON AND EVENING ACROSS THE REGION. FCST SOUNDINGS SHOW LOW LEVEL MOISTURE WILL STAY AROUND AND THEREFORE PATCHY DRIZZLE OR FREEZING DRIZZLE IS EXPECTED THROUGH TONIGHT. FREEZING DRIZZLE WOULD CONTINUE TO CAUSE A HAZARD THIS EVENING AND THEREFORE WW ADVISORIES AND WS WARNING CONTINUES TONIGHT. A COLD FRONT WILL MOVE THROUGH THE REGION LATE TONIGHT. SNOW SHOWERS ARE EXPECTED ACROSS THE WESTERN SLOPES. AN ADDITIONAL INCH OF SNOWFALL IS EXPECTED THROUGH MONDAY MORNING.
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&& .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
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WEAK HIGH PRESSURE BUILDS OVER THE AREA ON MONDAY AND CONTINUES INTO MONDAY NIGHT. SOME UPSLOPE SNOW SHOWERS IN THE WESTERN MOUNTAINS TO START THE DAY...BUT SHOULD END BY MID DAY. HIGHS ON MONDAY WILL MODERATE AS 85H TEMPS REALLY NOT THAT COLD...WITH READINGS STILL WELL BELOW SEASONAL NORMALS FOR EARLY MARCH. ON MON NIGHT...A WARM FRONT WILL APPROACH FROM THE SOUTHWEST AS HIGH PRESSURE RETREATS EAST. SUB-FREEZING SURFACE TEMPS...BUT PRECIP SHOULD HOLD OFF AS SHOWN BY 00Z ECMWF AND GFS.
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&& .LONG TERM /TUESDAY THROUGH SATURDAY/...
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ON TUE...AS THE WARM FRONT MOVES NORTHEAST PRECIP SHOULD INCREASE THROUGHOUT THE DAY. WED AFTERNOON TEMPS WILL BE THE WARMEST IN QUITE SOME TIME...AS 50S WILL BE PREVALENT...THE MEX MOS SHOWS L60S ACROSS SOUTHERN PORTIONS OF THE CWA. HOWEVER AMOUNT OF CLOUD COVER AND ANY PRECIP COULD TEMPER HIGHS ON WED. MODELS CONTINUE TO SHOW MORE ORGANIZED PRECIP FOR LATE WED INTO WED NIGHT AHEAD OF A STRONG COLD FRONT. AMOUNTS OF ONE INCH LIQUID ARE POSSIBLE WED NIGHT. THU-SAT...THE COLD FRONT WILL BE EAST OF THE AREA EARLY THUR AS HIGH PRESSURE BUILDS IN. DRY WEATHER EXPECTED THROUGH SATURDAY WITH BELOW NORMAL TEMPERATURES.
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&& .AVIATION /09Z SUNDAY THROUGH THURSDAY/...
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VFR CONDITIONS WILL BECOME MVFR/IFR QUICKLY AS -SN MOVES INTO THE REGION THIS MORNING. -SN IS EXPECTED TO CHANGE TO -PLFZRA BY LATE MORNING ACROSS THE TERMINALS. VSBYS WILL LIKELY IMPROVE ONCE -SN STOPS BUT CIGS ARE EXPECTED TO LOWER LATE THIS MORNING. IFR CIGS WILL CONTINUE THROUGH THE EVENING WITH THE EXCEPTION OF MRB. MIXING WILL LIKELY ALLOW MRB TO BECOME VFR TONIGHT. VSBYS WILL LIKELY DROP BACK TO IFR THIS EVENING DUE TO LOW LEVEL MOISTURE STAYING IN PLACE. VFR CONDITIONS MONDAY AND MONDAY NIGHT. VFR CONDITIONS EXPECTED EARLY TUESDAY...SUB-VFR POSSIBLE TUE NIGHT THROUGH WEDNESDAY NIGHT IN PRECIPITATION.
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&& .MARINE...
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LIGHT WINDS FROM HIGH PRESSURE WILL STAY PARKED OVER THE AREA THIS MORNING. A SOUTHERLY FLOW WILL BRIEFLY CHANNEL UP THE MAIN STEM OF THE DAY SUNDAY AFTN BUT LIKELY REMAIN BELOW SCA CRITERIA. THE FLOW WILL TURN TOWARD THE NORTHWEST BEHIND THE FRONT BY MONDAY. SCA GUSTS POSSIBLE MONDAY BEHIND THE COLD FRONT IN NW FLOW. WINDS EXPECTED TO BE 10KT OR LESS MONDAY NIGHT. WINDS WILL PICK UP PRIOR TO COLD FRONTAL PASSAGE WITH SCA POSSIBLE BEGINNING LATE TUESDAY NIGHT AND CONTINUING THRU FRONTAL PASSAGE ON WEDNESDAY NIGHT.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 3 AM EST MONDAY FOR DCZ001. MD...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MDZ501. WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 3 AM EST MONDAY FOR MDZ013-014-016>018-503>506. WINTER WEATHER ADVISORY UNTIL 3 AM EST MONDAY FOR MDZ003-004- 502. WINTER STORM WARNING FROM 7 AM THIS MORNING TO 3 AM EST MONDAY FOR MDZ005-006-011-507-508. VA...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR VAZ503. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR VAZ025>027-029-030-036>040-050-051-501-502-504-507-508. WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 3 AM EST MONDAY FOR VAZ052>054-506. WINTER WEATHER ADVISORY UNTIL 3 AM EST MONDAY FOR VAZ028-031- 505. WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS EVENING FOR VAZ055>057. WV...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR WVZ501-503- 505. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ055- 502-506. WINTER WEATHER ADVISORY UNTIL 3 AM EST MONDAY FOR WVZ050>053- 504. MARINE...NONE.
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&& $$ SYNOPSIS...HAS/SMZ NEAR TERM...HAS SHORT TERM...HAS LONG TERM...SMZ AVIATION...HAS/SMZ MARINE...HAS/SMZ

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