Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 260819 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 419 AM EDT THU MAR 26 2015 .SYNOPSIS...
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HIGH PRESSURE WILL CONTINUE TO MOVE OFF THE COAST OVERNIGHT. A WARM FRONT WILL PASS THROUGH THE AREA THURSDAY MORNING FOLLOWED BY A COLD FRONT THAT WILL MOVE THROUGH THURSDAY NIGHT. AN UPPER- LEVEL DISTURBANCE WILL PASS THROUGH THE AREA LATER FRIDAY THROUGH SATURDAY. HIGH PRESSURE WILL RETURN FOR SUNDAY AND CONTINUE INTO MONDAY.
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&& .NEAR TERM /THROUGH TONIGHT/...
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FRONT EXTENDING FROM LOW PRESSURE OVER THE ARKLATEX IS STILL IN A CAD POSITION EARLY THIS MORNING. IN FACT WHERE CLOUDS HAVE BEEN THINNER ACROSS NORTHERN AREAS...TEMPERATURES HAVE DROPPED INTO THE 30S. MAY TAKE SOME TIME FOR THIS TO LIFT NORTHWARD THIS MORNING...ESPECIALLY EAST OF THE BLUE RIDGE WHERE THICKER CLOUDS ARE EXPECTED TO BE IN PLACE. SHOWERS ARE DEVELOPING IN SE VA. THIS TREND IS EXPECTED TO CONTINUE NORTHWARD THIS MORNING AS A SOUTHERLY LLJ ADVECTS MUCH HIGHER MOISTURE OFF THE ATLANTIC. ENOUGH INSTBY IS DEPICTED TO ADD A CHANCE OF THUNDER WITH THIS ACTIVITY SE OF DC. SPC HAS ALSO HIGHLIGHTED THIS ARE FOR A MARGINAL SVR RISK TODAY...ALTHOUGH IT APPEARS FORCING WILL BEGIN WANING BEFORE THE BOUNDARY LAYER CAN BECOME MIXED ENOUGH FOR ANY GUSTS TO MAKE IT TO THE SFC. THERE MAY BE A LULL DURING THE EARLY AFTERNOON ESPECIALLY WEST OF THE BLUE RIDGE WHERE IT MAY NOT RAIN MUCH AT ALL TODAY. QUESTIONABLE HOW MANY BREAKS OF SUN THERE ARE...BUT CLOUDS MAY BE TOUGHER TO BREAK IN THE EAST. HIGHS HAVE BEEN LOWERED A BIT IN THE EAST...BUT STILL THINK MANY AREAS COULD PUSH THE 70S. THE COLD FRONT LOOKS LIKE IT WILL CROSS THE AREA BETWEEN 22 AND 04Z. HIGH RESOLUTION GUIDANCE IS COMING INTO RANGE AND ALMOST ALL SOLUTIONS DEPICT A NARROW CONVECTIVE LINE ALONG THE FRONT. HAVE MAINTAINED CHC THUNDER WORDING...AS MUCAPE APPEARS IT WILL ONLY BE AROUND 500 J/KG OR LESS. GUSTY WINDS CAN BE EXPECTED WITH THE SHOWERS...ALTHOUGH SVR LEVEL GUSTS SEEM TO BE A LOW PROBABILITY DUE TO THE LOW LEVEL WIND FIELDS. UPPER LEVEL JET STREAK INTERACTS WITH FRONT ALOFT TO PROVIDE ADDITIONAL PRECIP OVERNIGHT. AS TEMPS FALL...SNOW WILL BECOME LIKELY IN THE UPSLOPE REGIONS. NOT OUT OF THE QUESTION THERE COULD BE SOME MIX FARTHER EAST...BUT CONFIDENCE TOO LOW TO INCLUDE IN FORECAST FOR NOW. LOWS OUTSIDE OF THE MOUNTAINS GENERALLY IN UPPER 30S AND 40S.
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&& .SHORT TERM /FRIDAY/...
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SHOWERS WILL EXIT EAST PORTIONS FRIDAY MORNING. MOISTURE PROFILES SUGGEST THREAT OF UPSLOPE PRECIP IN WRN MTNS WILL DIMINISH TO SMALLER CHANCES. FRIDAY WILL BE MARKED BY CAA BUT A DOWNSLOPE COMPONENT WILL ALLOW FOR GOOD MIXING AND HIGHS IN THE MID 40S TO LOWER 50S.
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&& .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
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STRONG COLD ADVECTION AT LOW LEVELS CONTINUES AS THE CORE OF UNSEASONABLY COLD AIR MOVES OUT OF THE GREAT LAKES REGION AND INTO THE NORTHEAST...BRUSHING THE NORTHERN MID-ATLANTIC. 850 HPA TEMPS PROGGED IN THE -9C TO -13C RANGE SATURDAY. EXAMINATION OF UPPER AIR RECORDS SHOWS ONLY ABOUT A DOZEN TIMES HAS 850 TEMPS FALLEN TO -10C OR LOWER FROM MAR 27 INTO APRIL. WITH DECENT CAA ON SATURDAY... SHOULD BE ENOUGH MOISTURE FOR STRATO-CU DECK. WHERE CLOUDS HOLD... TEMPS WILL STRUGGLE INTO THE 40S EAST OF THE BLUE RIDGE AND LOW/MID 40S EAST OF THE BLUE RIDGE. HOWEVER...IF THE DECK GETS WIPED OUT DUE TO LACK OF MOISTURE AND/OR DOWNSLOPING THEN THE RELATIVE WARMTH OF LATE MARCH SUN COULD CAUSE TEMPS TO OVERCOME CAA AND RISE A CAT OR TWO HIGHER THEN FORECAST. STILL...UNSEASONABLY COLD AND BRISK ON SATURDAY. SUN-THU...HIGH PRES MOVES OVERHEAD ON SUNDAY...CHILLY START TO THE DAY WITH TEMPS WELL BELOW NORMAL...EVEN MID/UPPER TEENS IN FAR WRN MTN AREA. BY MON...TEMPS REBOUND BACK TO TO NEAR SEASONABLE NORMS BASED UPON HPC GUIDANCE AS HIGH PRES MOVES OFF SOUTHEAST US. ANOTHER COLD FRONT WILL PASS THROUGH MON NIGHT OR EARLY TUE. SOME DIFFERENCES IN MODELS ON TIMING OF THIS FRONT. NOT MUCH MOISTURE ASSOCIATED WITH IT. WED...HIGH PRESSURE AGAIN RETURNS TO THE REGION. ON THU...MODERATION IN TEMPS CONTINUES AS RETURN SW FLOW AROUND DEPARTING HIGH USHERS IN MILD AIR ACROSS THE REGION.
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&& .AVIATION /08Z THURSDAY THROUGH MONDAY/...
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CIGS AND VSBYS WILL LOWER THIS MORNING AS A WARM FRONT MOVES THROUGH...BUT SHOULD BE MAINLY VFR. SHOWERS POSSIBLE MAINLY ALONG AND EAST OF I-95. CONDITIONS IMPROVE BY MIDDAY/EARLY AFTN BUT SOUTHERLY WINDS WILL BECOME GUSTY. A COLD FRONT SWEEPS EASTWARD DURING THE EARLY EVENING HOURS WITH WIND SHIFT TO NW. LINE OF SHOWERS AND POSSIBLE EMBEDDED TSTMS ALONG FRONT...WITH POST-FRONTAL PRECIP AND LOWERED FLIGHT CONDITIONS POSSIBLE OVERNIGHT. EXPECT IMPROVEMENT BY FRIDAY WITH NW WINDS. ON SAT...EXPECT VFR CONDITIONS...EXCEPT SOME ISOLD MVFR IN SNOW SHOWERS WITH NW WINDS 10-20 KTS. HIGH PRESSURE MOVES OVERHEAD ON SUNDAY AND CONTINUES INTO MOD...WITH VFR CONDITIONS EXPECTED.
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&& .MARINE...
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LIGHT WINDS THROUGH EARLY MORNING. EXPECT SOUTHERLY WINDS TO INCREASE 20-30 KT AS WARM FRONT PASSES THIS MORNING. SHOWERS AND PERHAPS THUNDERSTORMS ARE POSSIBLE THROUGH EARLY AFTN. COLD FRONT CROSSES THIS EVENING WITH WIND SHIFT TO NW AND MORE SHOWERS AND EMBEDDED STORMS. WINDS CONTINUE TO GUST BEHIND THE FRONT. EXTENDED SCA THROUGH UNTIL FRIDAY AFTERNOON...AS MIXING MAY CONTINUE TO ALLOW HIGHER GUSTS TO REACH THE SFC. FRI NIGHT INTO SAT EXPECT SCA CONDITIONS IN COLD ADVECTION AND NW WINDS. HIGH PRESS BUILDS OVER THE WATERS ON SUNDAY AND CONTINUES INTO MON WITH WINDS FALLING BELOW SCA LEVELS EARLY SUNDAY MORNING.
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&& .TIDES/COASTAL FLOODING...
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SOUTHERLY FLOW WILL INCREASE AHEAD OF A COLD FRONT TODAY CAUSING AN RISE IN WATER LEVELS. TIDAL ANOMALIES MAY BE HIGH ENOUGH FOR MINOR FLOODING NEAR TIMES OF HIGH TIDE TODAY INTO TONIGHT. THE COLD FRONT WILL PASS THROUGH LATE THIS EVENING AND WITH A NORTHWEST FLOW...WATER LEVELS WILL DECREASE LATE TONIGHT.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 6 AM EDT FRIDAY FOR ANZ530>543.
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&& $$ SYNOPSIS...ADS/SMZ NEAR TERM...ADS SHORT TERM...ADS LONG TERM...SMZ AVIATION...ADS/SMZ MARINE...ADS/SMZ TIDES/COASTAL FLOODING...SMZ

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