Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 052311 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 611 PM EST FRI FEB 5 2016 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVERHEAD THROUGH SATURDAY. COASTAL LOW PRESSURE WILL PASS BY WELL TO THE SOUTH AND EAST SUNDAY. ANOTHER LOW PRESSURE SYSTEM MAY IMPACT THE AREA MONDAY INTO TUESDAY. THE LOW WILL MOVE AWAY FROM THE AREA DURING THE MIDDLE PORTION OF NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/... LOW PRESSURE HAS RAPIDLY MOVED NORTHEAST AND OFF THE SOUTHERN NEW ENGLAND COAST THIS AFTERNOON. AN UPPER LEVEL TROUGH WILL CONTINUE TO PASS OVER THE REGION THROUGH THIS EVENING. HIGH PRESSURE WILL BUILD INTO THE REGION TONIGHT WHILE COLD AIR ADVECTION CONTINUES. NW WINDS 20-25 MPH WITH GUSTS UP TO 35 MPH ARE EXPECTED THE REST OF THE AFTERNOON BECOMING 10-15 MPH TONIGHT. MOSTLY CLEAR CONDITIONS EXPECTED TONIGHT. TEMPS WILL DROP INTO THE 20S OVERNIGHT. HIGH PRESSURE WILL REMAIN OVERHEAD SATURDAY. WINDS WILL BECOME LIGHT AND SOUTHERLY WITH TEMPS REACHING THE MID 40S UNDER MOSTLY SUNNY CONDTIONS. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/... AN UPPER LEVEL TROUGH WILL DIG INTO THE SE US SATURDAY NIGHT AND SUNDAY. COASTAL LOW PRESSURE IS EXPECTED TO DEVELOP OFF THE CAROLINA COAST BY SUNDAY MORNING. ACROSS THE MID-ATLANTIC... HIGH PRESSURE PERSISTS OVERHEAD. CLOUDS WILL INCREASE SATURDAY NIGHT. MOST OF THE MODEL GUIDANCE HAS THE UPPER LEVEL TROUGH PUSHING THE COASTAL LOW OUT TO SEA AND THE MID-ATLANTIC WILL LIKELY NOT BE IMPACTED SUNDAY. CONFIDENCE IS MEDIUM THAT PRECIPITATION WILL STAY SOUTH OF THE REGION SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... A LARGE AREA OF LOW PRESSURE IN THE UPPER LEVELS SHOULD SPAWN A LOW PRESSURE SYSTEM AT THE SURFACE IN THE MID-ATLANTIC REGION OR CAROLINAS LATE MONDAY INTO MONDAY NIGHT. THIS NEWLY FORMED LOW COULD HAVE A MORE DIRECT IMPACT TO OUR REGION...BRINGING LIGHT TO MODERATE SNOW MONDAY NIGHT WITH COLDER AIR TO SUPPORT THE NEW LOW. A FEW INCHES OF SNOW CANNOT BE RULED OUT. ONE SIMILARITY WITH THE EUROPEAN MODEL AND THE GFS MODEL WITH THIS NEW LOW IS BOTH CLOSE OFF THE NEW LOW NEAR THE MID-ATLANTIC COAST TUESDAY BEFORE PIVOTING IT NORTHWARD TOWARD NEW ENGLAND TUESDAY NIGHT. THE DIFFERENCE IN THE POSITION OF THIS CLOSED LOW WILL DETERMINE WHETHER THE MID-ATLANTIC REGION GETS HIT WITH MODERATE SNOW ACCUMULATIONS OR A MIX OF RAIN AND SNOW SHOWERS WILL LITTLE SNOW ACCUMULATION. AT THIS TIME...THE EUROPEAN MODEL CLOSES THE LOW NEAR THE MOUTH OF THE CHESAPEAKE BAY. THE GFS MODEL CLOSES THE LOW NEAR THE MOUTH OF THE DELAWARE BAY...FARTHER NORTH. WE HAVE A CHANCE OF RAIN OR SNOW IN OUR REGION TUESDAY THEN A CHANCE OF SNOW SHOWERS TUESDAY NIGHT. THE MAIN UPPER LEVEL SUPPORT BEHIND THE COASTAL LOW WILL SLOWLY PIVOT FROM THE OHIO VALLEY...ACROSS THE REGION...AND OFFSHORE WEDNESDAY AND WEDNESDAY NIGHT. SOME UPSLOPE SNOW SHOWERS MAY EXIST IN THE POTOMAC HIGHLANDS WITH COLDER AIR ALOFT PUNCHING INTO THE REGION. A LINGERING SNOW SHOWER MAY BE NEAR THE CHESAPEAKE BAY AS WELL. ELSEWHERE...COLDER AND DRIER AIR WILL FILTER INTO THE REGION AS HIGH PRESSURE BUILDS IN FROM THE WEST. HIGH PRESSURE SHOULD DOMINATE THURSDAY WITH CHILLY AND DRY AIR. THE GFS IS A LITTLE MORE PRONOUNCED WITH AN UPPER LEVEL DISTURBANCE LATE THURSDAY AND THURSDAY NIGHT THAN THE EUROPEAN. AT BEST...THERE COULD BE A FEW SNOW SHOWERS IN PARTS OF THE REGION. THE CONFIDENCE IS LOW. AS FOR FRIDAY...CONFIDENCE REMAINS LOW ON THE WEATHER SINCE THE EUROPEAN MODEL TAKES A STORM SYSTEM ALONG THE OHIO VALLEY INTO THE MID-ATLANTIC REGION WHILE THE GFS MODEL HAS HIGH PRESSURE BEING THE DOMINANT FEATURE. && .AVIATION /23Z FRIDAY THROUGH WEDNESDAY/... VFR CONDTIONS EXPECTED TODAY THROUGH SATURDAY AS HIGH PRESSURE MOVES INTO THE REGION. NW WINDS 15-20 GUSTS UP TO 35 KTS EXPECTED THIS AFTERNOON BEFORE DIMINISHING TO 10-15 KTS OVERNIGHT. LIGHT S WINDS EXPECTED SATURDAY. HIGH PRESSURE REMAINS IN PLACE THROUGH SUNDAY. VFR CONDITIONS EXPECTED. IFR OR LIFR CONDITIONS MONDAY NIGHT WITH PERIODS OF LIGHT TO MODERATE SNOW. WINDS EAST BECOMING NORTHEAST AROUND 5 KNOTS. MVFR TO BRIEFLY IFR CONDITIONS TUESDAY WITH A CHANCE OF LIGHT RAIN OR LIGHT SNOW. WINDS BECOMING NORTHWEST 5 TO 10 KNOTS. && .MARINE... GUSTY WINDS CONTINUE ON THE WATERS TODAY AND THIS EVENING. GUSTS UP TO 30 KT HAVE BEEN REPORTED AND WILL DIMINISH INTO THE EVENING HOURS. SCA IS IN EFFECT FOR ALL WATERS THROUGH THE EARLY EVENING. SCA CONTINUE ON THE BAY AND LOWER TIDAL POTOMAC THROUGH EVENING. HIGH PRESSURE BUILDS INTO THE REGION TONIGHT AND REMAINS IN PLACE SATURDAY AND SUNDAY. WINDS WILL LIKELY INCREASE SUNDAY NIGHT AS A COASTAL LOW DEVELOPS SOUTH OF THE WATERS. SMALL CRAFT CONDITIONS ARE POSSIBLE MONDAY INTO TUESDAY DEPENDING ON THE STRENGTH OF DEVELOPING LOW PRESSURE. && .HYDROLOGY... RIVER FLOODING IS COMING TO AN END AS WATER LEVELS DROP BELOW THEIR FLOOD STAGES. MINOR FLOODING IS STILL OCCURRING ON THE MAINSTEM POTOMAC AT EDWARDS FERRY. PLEASE SEE FLOOD WARNING FOR MORE INFORMATION. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ530>534-537>543. && $$ SYNOPSIS...HAS NEAR TERM...HAS SHORT TERM...HAS LONG TERM...KLW AVIATION...HAS/KLW MARINE...HAS/KLW HYDROLOGY...HAS

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