Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 271440 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 940 AM EST FRI FEB 27 2015 .SYNOPSIS...
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HIGH PRESSURE WILL BUILD OVERHEAD THROUGH SATURDAY. THE HIGH WILL MOVE OFF THE COAST SUNDAY AND ANOTHER COLD FRONT WILL PASS THROUGH THE AREA SUNDAY NIGHT. A WARM FRONT AND LOW PRESSURE WILL CROSS THE AREA TUESDAY AND WEDNESDAY.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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A COLD FRONT WILL DROP SOUTH OF SOUTHERN MARYLAND BY NOON. ANY LEFTOVER LIGHT SNOW OR FLURRIES WILL TAPER OFF BY THEN. HIGH PRESSURE WILL APPROACH FROM THE OHIO VALLEY BEHIND THE COLD FRONT FOR THIS AFTERNOON. A NORTHWEST FLOW AHEAD OF THE HIGH WILL USHER IN COLD CONDITIONS. IN FACT...TEMPERATURES WILL HOLD NEARLY STEADY TODAY IN THE 20S AND LOWER 30S. THERE IS A LITTLE INSTABILITY IN THE FORECAST SOUNDINGS DUE TO THE COLD ADVECTION. HOWEVER...THERE IS NOT MUCH IN THE WAY OF SYNOPTIC LIFT. THEREFORE...A FEW FLURRIES ARE POSSIBLE THIS AFTERNOON BUT NO SNOW ACCUMULATION IS EXPECTED FOR LOCATIONS EAST OF THE ALLEGHENY HIGHLANDS. LIGHT SNOW ACCUMULATIONS ARE POSSIBLE ALONG AND WEST OF THE ALLEGHENY FRONT DUE TO AN UPSLOPE FLOW.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... A SPRAWLING AREA OF HIGH PRESSURE IN THE CENTRAL CONUS WL BE WORKING EWD TNGT-SAT. CLDS WL BECOME MORE SCARCE AS SUBSIDENCE INCREASES. THERE IS DCPLG POTL TNGT. IF THAT OCCURS...THEN TEMPS CUD TUMBLE. HV NOT REFLECTED THAT IN DATABASE /AM HOLDING ONTO 5 KT WIND/...BUT IF FCST WERE TO GO ASTRAY...THATS MOST LKLY WHERE. AM USING MOS MEAN... WHICH YIELDS MIN-T BTWN MID SINGLES WEST TO MID TEENS EAST. CORE OF COLD AIR WL BE OVER/JUST N OF CWFA SAT...SPCLY IN THE MRNG. THUS...THIS WL BE THE COLDEST DAY BEFORE REBOUND OCCURS. MAXT INTHE 20S EVERYWHERE. FURTHER...THINK THERE WL BE ENUF MSTR IN THE COLUMN FOR AT LEAST PTCLDY SKIES. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE WILL BE LOCATED ACROSS NEW ENGLAND AND THE MID- ATLANTIC SATURDAY NIGHT WHILE A JET STREAK MOVES NORTHWARD INTO THE MID-WEST. LOW PRESSURE WILL INTENSIFY ACROSS THE CENTRAL PLAINS AS A SHORTWAVE TROUGH DROPS INTO THE NRN PLAINS SUNDAY. WARM AIR ADVECTION AHEAD OF THE SYSTEM WILL BRING GULF AND ATLANTIC MOISTURE INTO THE MID-ATLANTIC SUNDAY AFTERNOON. PRECIPITATION IS EXPECTED TO MOVE INTO THE POTOMAC HIGHLANDS SUN MORNING AND SPREAD EASTWARD. PWATS ARE EXPECTED TO DOUBLE DURING THE DAY. HIGH PRESSURE IS EXPECTED TO KEEP COLD AIR IN PLACE ACROSS THE MID-ATLANTIC LEADING TO SUB FREEZING TEMPERATURES AS PRECIPITATION MOVES INTO THE REGION. WINDS ARE EXPECTED TO BECOME SOUTHERLY SUNDAY MORNING BUT LIGHT AND WARM AIR ADVECTION WILL LIKELY BE SLOW UNTIL WINDS INCREASE...WHICH MAY NOT HAPPEN DURING THE DAY. IF THAT IS THE CASE...TEMPS WILL BE SLOWER TO RISE AND AREAS ACROSS CENTRAL VA MAY SEE A PERIOD OF WINTRY PRECIPITATION. GUIDANCE SHOWS TEMPS RISING ABOVE FREEZING SUNDAY IN THIS AREA BUT DUE TO THE LIGHT WINDS LEFT A CHANCE OF IP/ZR ACROSS THE ENTIRE AREA. PRECIPITATION IS EXPECTED TO BEGIN AS SNOW BUT THEN SWITCH TO IP/ZR BY SUNDAY AFTERNOON. THE BEST CHANCE OF IP/ZR AND LIGHT ICE ACCUMULATION WILL BE FURTHER NORTH NEAR THE MD/PA BORDER WHERE SFC TEMPS WILL STAY NEAR OR BELOW FREEZING DURING THE DAY AND POSSIBLY INTO THE EVENING. AREAS SOUTH OF DC MAY NOT SEE MUCH QPF AS MUCH OF THE FORCING IS FURTHER NORTH HOWEVER...MOISTURE ADVECTION WILL LIKELY LEAD TO A PERIOD OF RA/IP/ZR. A COLD FRONT MOVES THROUGH THE REGION SUNDAY NIGHT AND DRY CONDITIONS ARE EXPECTED MONDAY WITH THE EXCEPTION OF UPSLOPE SN/RA SHOWERS ALONG THE WESTERN SLOPES. HIGH PRESSURE MOVES INTO THE REGION MONDAY NIGHT AND TUESDAY. A COLORADO LOW WILL DEVELOP EARLY NEXT WEEK AND TRACK ACROSS THE CENTRAL PLAINS AND EVENTUALLY THE GREAT LAKES. ANOTHER ROUND OF WARM AIR ADVECTION WILL BUILD INTO THE REGION TUESDAY. COLD SURFACE TEMPS WILL PERSIST ACROSS THE MID- ATLANTIC AND ANOTHER ROUND OF ICING IS POSSIBLE TUESDAY NIGHT INTO WEDNESDAY BEFORE A WARM FRONT PASSAGE. THIS WARM FRONT WILL BRING MUCH RELIEF TO THE MID-ATLANTIC WITH TEMPERATURES FORECAST IN THE 50S TO NEAR 60 BY WED AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE REGION BY THURSDAY AND TEMPS WILL LOWER TO NEAR NORMAL. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/...
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VFR CONDITIONS ARE EXPECTED TODAY. A FEW FLURRIES CANNOT BE RULED OUT. NORTHWEST WINDS WILL GUST AROUND 15 TO 20 KNOTS. WINDS SHUD RELAX AND CLDS SLOWLY SCATTER OUT TNGT. LGT WNDS AND SCT CLDS WL CARRY INTO SAT. A WINTRY MIX IS POSSIBLE SUNDAY AFTERNOON AT THE TERMINALS AND MVFR/IFR CONDITIONS ARE LIKELY AS PRECIPITATION MOVES INTO THE REGION. ANOTHER ROUND OF WINTRY MIX IS POSSIBLE TUESDAY AND TUESDAY NIGHT.
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&& .MARINE...
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NORTH TO NORTHWEST WINDS ARE EXPECTED BEHIND A COLD FRONT TODAY. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS DURING THIS TIME. WL CONT ADVY FOR TNGT...BUT HV PULLED BACK N OF POOLES ISLAND. HIGH PRESSURE WILL PERSIST ACROSS THE AREA SATURDAY NIGHT BEFORE MOVING OFF THE COAST SUNDAY. SCA CONDITIONS ARE POSSIBLE SUNDAY NIGHT INTO MONDAY AHEAD AND BEHIND A FRONTAL PASSAGE.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST SATURDAY FOR ANZ531>534- 537-539>541-543. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ530- 535-536-538-542.
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&& $$ SYNOPSIS...BJL/HTS NEAR TERM...BJL/HTS SHORT TERM...HTS LONG TERM...HAS AVIATION...BJL/HAS/HTS MARINE...BJL/HAS/HTS

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