Area Forecast Discussion
Issued by NWS Sterling, VA

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995 FXUS61 KLWX 051528 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1028 AM EST FRI FEB 5 2016 .SYNOPSIS...
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HIGH PRESSURE WILL BUILD OVERHEAD LATER TODAY 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.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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LOW PRESSURE WILL CONTINUE TO SPEED AWAY FROM THE MID-ATLANTIC COAST. THE ASSOCIATED PRECIPITATION SHIELD HAS MOVED EAST OF THE CHESAPEAKE BAY. A STRONG PRESSURE GRADIENT BEHIND THE COASTAL LOW HAS LED TO GUSTY NW WINDS WITH GUSTS AS HIGH AS 35 MPH THIS MORNING. THE COLD AIR ADVECTION AHEAD OF THE UPPER LEVEL TROUGH AXIS HAS ALSO ALLOWED SCATTERED SNOW SHOWERS TO DEVELOP ACROSS THE I-95 CORRIDOR. LIGHT SNOW AND FLURRIES ARE EXPECTED ACROSS THE BALTIMORE AND WASHINGTON DC METRO FOR THE REST OF THE MORNING. LITTLE TO NO ACCUMULATION IS EXPECTED AS TEMPERATURES ARE IN THE MID TO UPPER 30S AND WILL SLOWLY RISE TO THE LOW 40S BY AFTERNOON. IF ANY ACCUMULATION FORMS IT WOULD LIKELY BE ON GRASSY SURFACES. SNOW SHOWERS MAY REDUCE VISIBILITES TO LESS THAN A MILE AT TIMES SO CAUTION IS STILL NECESSARY THIS MORNING ESPECIALLY WHILE TRAVELING. HIGH PRESSURE WILL SURGE INTO THE REGION TODAY AND WINDS WILL STAY GUSTY THROUGH THE AFTERNOON. CLEARING IS MOVING INTO THE REGION AND SUNSHINE IS EXPECTED FOR THE AREA IF THIS AFTERNOON.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... HIGH PRESSURE BUILDS IN AND WILL BE IN CONTROL THROUGH THE WEEKEND. DEVELOPING LOW OFF THE SOUTHEAST COAST ON SATURDAY WILL STAY WELL SOUTH AND EAST OF THE REGION. HIGHS EXPECTED IN THE 40S ON SATURDAY AND 40S TO LOW 50S SUNDAY. LOWS IN THE 20S TO LOW 30S...COLDEST TONIGHT. && .LONG TERM /MONDAY THROUGH THURSDAY/... CONFIDENCE REMAINS HIGH FOR A HIGH AMPLITUDE PATTERN WITH A POTENT UPPER-LEVEL TROUGH DIGGING OVER THE MIDWEST MONDAY AND SHIFTING EASTWARD INTO THE EASTERN CONUS TUESDAY. GIVEN THE HIGH AMPLITUDE PATTERN...THE UPPER-LEVEL TROUGH IS EXPECTED TO DIG QUITE FAR TO THE SOUTH AND A CLOSED UPPER-LEVEL LOW IS LIKELY TO DEVELOP. THE CLOSED UPPER-LEVEL LOW WILL TRACK OVER OUR AREA LATER MONDAY INTO TUESDAY. COASTAL LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE MID-ATLANTIC COAST AS THE UPPER-LEVEL LOW INTERACTS WITH THE BAROCLINIC ZONE ALONG THE COAST. HOWEVER...THE UNCERTAINTY STILL REMAINS AS TO HOW STRONG THE LOW WILL GET BEFORE MOVING OFF TO OUR NORTH AND EAST. IF THE UPPER-LEVEL LOW DIGS FARTHER SOUTH AND THE COASTAL LOW INTENSIFIES BEFORE MOVING OFF TO OUR NORTH AND EAST...THEN A SIGNIFICANT WINTER STORM IS POSSIBLE ACROSS THE MID- ATLANTIC. HOWEVER...IF THE LOW MOVES OFF TO OUR NORTH AND EAST BEFORE RAPIDLY INTENSIFYING...THEN LIGHTER QPF AMOUNTS ARE EXPECTED WITH A RAIN/SNOW MIX. BOTH SCENARIOS ARE STILL POSSIBLE AT THIS TIME. THE LOW WILL MOVE AWAY FROM THE WEDNESDAY AND THURSDAY...BUT THE UPPER-LEVEL TROUGH WILL REMAIN OVERHEAD. COLD CONDITIONS ARE EXPECTED AND A FEW SNOW SHOWERS ARE POSSIBLE DUE TO THE UPPER-LEVEL TROUGH. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/...
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LIGHT SNOW CONTINUES ACROSS THE DCA/BWI/MTN REGION. MVFR VSBYS POSSIBLE THROUGH THE MORNING. OTHERWISE...GUSTY NORTHWEST WINDS UP TO 30 KNOTS WILL DEVELOP AND CONTINUE THROUGH THE DAY. AFTERWARD...WINDS WEAKEN TONIGHT AND VFR CONDITIONS ARE EXPECTED THROUGH SUNDAY. AN UPPER-LEVEL LOW WILL LIKELY BRING SOME RAIN OR SNOW SHOWERS TO THE AREA LATER MONDAY INTO TUESDAY ALONG WITH SUBVFR CONDITIONS. UNCERTAINTY REMAINS ON HOW MUCH A COASTAL LOW MAY IMPACT THE AREA. IF THE COASTAL LOW INTENSIFIES BEFORE MOVING AWAY...THEN HEAVIER SNOW IS POSSIBLE. THE LOW WILL MOVE AWAY FROM THE AREA WEDNESDAY. GUSTY NORTHWEST WINDS ARE EXPECTED BEHIND IT.
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&& .MARINE... GUSTY NORTHWEST WINDS WILL INCREASE IN INTENSITY THIS MORNING BEHIND DEPARTING COASTAL LOW. WINDS WILL GUST UP TO AROUND 35 KNOTS FOR A TIME THIS MORNING SO HAVE UPGRADED THE LOWER CHESAPEAKE AND LOWER POTOMAC TO GALE WARNINGS. SMALL CRAFT ADVISORIES WILL CONTINUE ELSEWHERE. AFTER 17Z (12 NOON)...WINDS WILL GRADUALLY WEAKEN BACK TO SCA CRITERIA OVER ALL WATERS. HIGH PRESSURE WILL THEN MOVE OVER THE WATERS TONIGHT AND INTO THE WEEKEND WITH SCA CONDITIONS ENDING LATE THIS EVENING. NO MARINE HAZARDS EXPECTED SATURDAY THROUGH MONDAY. LOW PRESSURE WILL LIKELY IMPACT THE WATERS MONDAY INTO TUESDAY. DETAILS ON HOW STRONG THE LOW WILL BE ARE UNCERTAIN AT THIS TIME...BUT A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS. THE LOW WILL MOVE AWAY FROM THE WATERS WEDNESDAY...BUT GUSTY NORTHWEST WINDS ARE LIKELY BEHIND THE DEPARTING LOW. && .HYDROLOGY...
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RIVER FLOODING IS COMING TO AN END THIS MORNING AS WATER LEVELS DROP BELOW FLOOD STAGES. MINOR FLOODING IS STILL OCCURRING ON THE MAINSTEM SHENANDOAH AT MILLVILLE...AND THE MAINSTEM POTOMAC BETWEEN PORT OF ROCKS AND EDWARDS FERRY.
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&& .TIDES/COASTAL FLOODING...
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LITTLE FALLS GAUGE HAS CRESTED UNDER FLOOD STAGE AND WILL CONTINUE TO FALL TODAY. COASTAL FLOODING IS NOT EXPECTED AT THIS TIME.
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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 10 PM EST THIS EVENING FOR ANZ530>532-538>540. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ533- 534-537-541>543. GALE WARNING UNTIL NOON EST TODAY FOR ANZ533-534-537-541>543. SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ535- 536.
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&& $$ SYNOPSIS...BJL/MM NEAR TERM...HAS SHORT TERM...MM LONG TERM...BJL AVIATION...BJL/MM/HAS MARINE...BJL/MM/HAS HYDROLOGY...HAS TIDES/COASTAL FLOODING...HAS

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