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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