Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 160109 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 909 PM EDT TUE APR 15 2014 .SYNOPSIS... AN EXCEPTIONALLY COLD AIRMASS FOR THIS TIME OF YEAR WILL QUICKLY TAKE HOLD OF THE AREA BY LATE THIS EVENING. HIGH PRESSURE WILL BUILD OVERHEAD DURING THE MIDDLE OF THE WEEK...THEN MOVE OFFSHORE LATE IN THE WEEK. AN AREA OF LOW PRESSURE MAY AFFECT THE AREA DURING THE FIRST HALF OF THE WEEKEND. && .NEAR TERM /THROUGH WEDNESDAY/...
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THE COLD FRONT HAS MOVED OFF TO OUR EAST AND GUSTY NORTHWEST WINDS TONIGHT WILL CONTINUE TO USHER IN UNUSUALLY COLD CONDITIONS BEHIND THE BOUNDARY. PRECIPITATION NEAR AND EAST OF I-95 THIS EVENING WILL GRADUALLY END FROM WEST TO EAST TOWARD MIDNIGHT. THERE HAVE BEEN REPORTS OF SLEET AND SNOW AS COLDER AIR INTERACTS WITH THE PRECIPITATION. ANY SNOW ACCUMULATION WILL BE CONFINED TO GRASSY SURFACES...MAINLY NEAR THE MASON-DIXON LINE ACROSS THE HIGHER ELEVATIONS. SNOWFALL ACCUMULATIONS AROUND AN INCH ARE POSSIBLE ACROSS THESE AREAS. ELSEWHERE...LITTLE OR NO SNOW ACCUMULATION IS EXPECTED BEFORE PRECIPITATION ENDS LATE THIS EVENING. DRIER AIR WILL WORK ITS WAY INTO THE AREA LATE TONIGHT AS HIGH PRESSURE APPROACHES FROM THE WEST. HOWEVER...IT WILL TURN OUT BLUSTERY AND VERY COLD FOR THIS TIME OF YEAR. A FREEZE WARNING REMAINS IN EFFECT FOR LOCATIONS EAST OF THE BLUE RIDGE MOUNTAINS WHERE THE GROWING SEASON HAS BEGUN. MIN TEMPS WILL RANGE FROM UPPER TEENS ALONG THE ALLEGHENY FRONT...TO THE MID AND UPPER 20S IN THE WASHINGTON AND BALTIMORE SUBURBS...TO THE LOWER 30S IN DOWNTOWN WASHINGTON AND BALTIMORE AS WELL AS SOUTHERN MARYLAND. HIGH PRESSURE WILL BUILD OVER THE REGION WEDNESDAY...BRINGING DRY CONDITIONS ALONG WITH PLENTY OF SUNSHINE. HOWEVER...IT WILL BE CHILLY FOR THIS TIME OF YEAR. MAX TEMPS WILL RANGE FROM NEAR 40 IN THE MOUNTAINS TO THE UPPER 40S AND LOWER 50S ELSEWHERE. THE MAX TEMP FORECASTS ARE AROUND 15 TO 20 DEGREES BELOW CLIMO.
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&& .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... HIGH PRESSURE WEDNESDAY NIGHT ALONG WITH CLEAR SKIES/LIGHT WINDS WILL PRODUCE A MORE TYPICAL RADIATIONAL COOLING NIGHT AND THEREFORE TEMPERATURES ARE EXPECTED TO BOTTOM OUT AGAIN. FREEZE WATCH HAS BEEN ISSUED EAST OF THE BLUE RIDGE INTO THURSDAY MORNING. HIGH PRESSURE CENTER MOVES OFF THE NORTHEAST COAST AND THEN WEDGES DOWN THROUGH THE MID-ATLANTIC TO END THE WEEK. TEMPS MAY REBOUND SOME...BUT WILL STILL BE BELOW AVERAGE THROUGH FRIDAY. CLOUDS LIKELY INCREASE THURSDAY NIGHT INTO FRIDAY WITH A WEAK DISTURBANCE OFF THE COAST AND ALSO AHEAD OF THE NEXT UPSTREAM SHORTWAVE TROUGH BUT FAVOR A DRY FORECAST ATTM. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... A COUPLE AREAS OF LOW PRESSURE WILL BRUSH PAST THE REGION FOR THE FIRST PART OF THIS WEEKEND...WITH A CHANCE OF RAIN MAINLY DURING THE DAY SATURDAY. THE MODELS HAVE MOST RECENTLY TRENDED DOWNWARD WITH THE PROBABILITY OF RAIN AND WITH RAINFALL AMOUNTS AS A RESULT OF ENERGY FROM THE NORTHERN AND SOUTHERN BRANCHES OF THE JET STREAM REMAINING SPLIT INSTEAD OF PHASING. THIS LEAVES TO TWO WEAKER WAVES OF LOW PRESSURE...ONE PASSING TO THE NORTHWEST ACROSS THE GREAT LAKES AND THE OTHER MOVING OFFSHORE INTO THE ATLANTIC. ANOTHER PUSH OF COOL AIR WILL ACCOMPANY HIGH PRESSURE MOVING DOWN FROM CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND...THOUGH NOT NEARLY AS COLD OF AN AIRMASS AS IS EXPECTED DURING THE MIDDLE OF THIS WEEK. LOW PRESSURE WILL APPROACH THE AREA FROM THE WEST EARLY NEXT WEEK BRINGING A CHANCE OF RAIN MONDAY INTO TUESDAY. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
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ANY LEFTOVER PRECIPITATION WILL END BY LATE THIS EVENING. VFR CONDITIONS ARE EXPECTED OVERNIGHT WITH GUSTY NORTHWEST WINDS. VFR CONDITIONS WILL CONTINUE THROUGH WEDNESDAY. WINDS WILL GRADUALLY SHIFT TO THE EAST-NORTHEAST AND DECREASE IN SPEED WEDNESDAY AFTERNOON. HIGH PRESSURE WED MOVES OFF THE COAST TOWARD THE END OF THE WEEK. ONSHORE FLOW MAY LEAD TO FLIGHT RESTRICTIONS IN LOW CLOUDS THURSDAY NIGHT INTO FRIDAY. SUB-VFR POSSIBLE IN RAIN SATURDAY...THEN VFR SUNDAY. EASTERLY WINDS 5 TO 10 KNOTS SATURDAY BECOME WEST OR NORTHWEST AROUND 10 KNOTS BY SUNDAY.
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&& .MARINE...
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WILL CONTINUE WITH A GALE WARNING FOR THE WATERS TONIGHT. THE HIGHEST CONFIDENCE FOR GALE-FORCE WINDS WILL BE ACROSS THE MIDDLE PORTION OF THE BAY AND LOWER TIDAL POTOMAC RIVER. ELSEWHERE...IT WILL TURN OUT TO BE MORE MARGINAL WITH GUSTS AROUND 30 TO 35 KNOTS. SCA CONTINUES FOR MUCH OF WEDNESDAY...BEFORE GRADIENT RELAXES LATER IN THE AFTERNOON FOR DIMINISHING WINDS. NO SCA CONDITIONS ARE EXPECTED WEDNESDAY NIGHT. MARGINAL SCA POSSIBLY AGAIN LATE THURSDAY OR THURSDAY NIGHT WITH EAST WINDS. SMALL CRAFT ADVISORY LEVEL WIND GUSTS ARE POSSIBLE FOR PARTS OF THE WATERS SATURDAY NIGHT INTO SUNDAY IN A TIGHTENING PRESSURE GRADIENT BETWEEN LOW PRESSURE DEPARTING TO THE NORTH AND HIGH PRESSURE BUILDING IN FROM THE WEST.
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&& .TIDES/COASTAL FLOODING...
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GUSTY NORTHWEST WINDS TONIGHT INTO WEDNESDAY WILL CAUSE WATER LEVELS TO RAPIDLY DECREASE. TIDAL BLOWOUT CONDITIONS ARE EXPECTED WEDNESDAY WITH ANOMALIES AROUND 2 FEET BELOW NORMAL.
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&& .CLIMATE...
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JUST A DAY AFTER RECORD HIGH MINIMUM TEMPERATURES WERE OBSERVED...AN EXCEPTIONALLY COLD AIRMASS FOR THIS TIME OF YEAR WILL APPROACH RECORD MINIMUM TEMPERATURES EARLY WEDNESDAY MORNING. BELOW IS A TABLE OF RECORD MINIMUM TEMPERATURES FOR APRIL 16 ALONG WITH THE FORECAST MINIMUM TEMPERATURE FOR EARLY WEDNESDAY MORNING. SITE...PREVIOUS RECORD...FORECAST MINIMUM... DCA....29 F IN 1928......32 F............... BWI....30 F IN 1962......29 F............... IAD....28 F IN 1981......28 F...............
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING FOR DCZ001. FREEZE WARNING FROM 3 AM TO 9 AM EDT WEDNESDAY FOR DCZ001. MD...FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING FOR MDZ004>007-009>011-013-014-016>018. FREEZE WARNING FROM 3 AM TO 9 AM EDT WEDNESDAY FOR MDZ011-013- 014-016>018. FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT WEDNESDAY FOR MDZ004>007-009-010. VA...FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING FOR VAZ036>040-042-050>057-501-502. FREEZE WARNING FROM 3 AM TO 9 AM EDT WEDNESDAY FOR VAZ052>057. FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT WEDNESDAY FOR VAZ036>040-042-050-051-501-502. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT WEDNESDAY FOR ANZ531>534-537-539>541-543. GALE WARNING UNTIL 6 AM EDT WEDNESDAY FOR ANZ530>543. SMALL CRAFT ADVISORY FROM 6 AM TO 2 PM EDT WEDNESDAY FOR ANZ530-535-536-538-542. && $$ SYNOPSIS...DFH NEAR TERM...BJL SHORT TERM...BPP LONG TERM...DFH AVIATION...BJL/BPP/CAS MARINE...BJL/BPP/CAS TIDES/COASTAL FLOODING...BJL CLIMATE...BJL

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