Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 281525 AAA
AFDLWX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1025 AM EST WED JAN 28 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVERHEAD THROUGH TONIGHT BEFORE MOVING
OFF THE COAST THURSDAY. A COLD FRONT WILL PASS THROUGH THE AREA
THURSDAY NIGHT AND HIGH PRESSURE WILL BUILD IN BEHIND THIS SYSTEM
FRIDAY THROUGH SATURDAY. LOW PRESSURE WILL IMPACT THE REGION
SUNDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
QUITE A DIFFERENT DAY TODAY THAN THE PAST COUPLE...AS THE ACTIVE
LATE JAN CONTINUES. TODAY IS THE ONE-DAY REPRIEVE...IN TERMS OF
CLOUDS AND PRECIP AT LEAST. CLEAR SKIES THROUGHOUT THE DAY...WHICH
ONE THE HAND WILL HELP OUR TEMPS QUICKLY CLIMB OUT OF A DEEP
FREEZE FROM OUR OVERNIGHT LOWS BUT ALSO IS EVIDENCE THAT
SUBSIDENCE IS IN CONTROL AND EFFICIENTLY DROPPING GUSTY AND COLD
LOW LEVEL WINDS DOWN TO THE SFC. SO DESPITE AMPLE SUN...IT OUR
WIND CHILLS WILL REMAIN WELL INTO THE TEENS AND 20S THROUGHOUT
THE DAYTIME HRS. VIS SATELLITE SHOWS THE NRN AND WRN HALVES OF THE
CWA UNDER DECENT SNOW COVER...WHICH WILL KEEP A BIT OF A LID OF
TEMPS TODAY.

THE GUSTY WINDS OF THIS AFTN WILL SUBSIDE INTO THE LATE EVE HRS.
COMBINE THE CLEAR SKIES W/ VERY LOW DEWPOINTS HOWEVER AND AIR
TEMPS WILL ONCE AGAIN CRASH DOWN INTO THE 20S AND TEENS OVER THE
NRN TIER AND THE APLCNS. WINDS CHILLS WON`T BE AS CHILLY OVERNIGHT
AS WINDS SUBSIDE W/ HIGH PRESSURE ROLLING OVER THE REGION TO THE
NORTH.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
CLOUDS WILL BE ON THE INCREASE THURSDAY MORNING AS THE NEXT
CLIPPER SYSTEM APPROACHES FROM THE WEST. IT APPEARS MORE LIKELY
FOR THIS CLIPPER TO PASS TO THE NORTH OF OUR REGION LATER THURSDAY
BUT NONETHELESS THERE WILL BE A CHANCE FOR PRECIPITATION DURING
THE DAY. MARGINAL TEMPERATURES WILL BE IN PLACE AS THE
PRECIPITATION MOVES IN. UPSLOPE SNOW WILL BE POSSIBLE OVER THE
WESTERN SLOPES OF THE ALLEGHENY FRONT. TO THE EAST...TEMPERATURES
WILL BE A BIT MILDER AND WE HAVE HIGHLIGHTED THE POTENTIAL FOR A
WINTRY MIX OF RAIN/SNOW DURING THE DAY GENERALLY N AND W OF
WASHINGTON DC. AREAS TO THE SOUTH WILL SEE MOSTLY LIQUID. THERE IS
STILL SOME UNCERTAINTY REGARDING P-TYPES. EITHER WAY...QPF WITH
THIS SYSTEM WILL BE LIGHT. AFTERNOON HIGH TEMPERATURES IN THE
LOWER TO MIDDLE 30S NORTH AND UPPER 30S SOUTH WILL BE COMMON.

LOW PRESSURE WILL PASS BY TO THE NORTH THURSDAY NIGHT WHILE THE
COLD FRONT ASSOCIATED WITH THIS SYSTEM MOVES THROUGH OUR AREA.
MOST OF THE DYNAMICS WILL REMAIN WELL TO OUR NORTH...BUT THERE CAN
BE A PERIOD OF LIGHT PRECIPITATION THURSDAY EVENING AHEAD OF THE
FRONT. THE BEST CHANCE FOR WINTRY PRECIPITATION WILL BE ACROSS THE
NORTHERN PORTIONS OF THE CWA...CLOSER TO THE MASON-DIXON LINE
WHERE PRECIPITATION IS MOST LIKELY AND TEMPS WILL BE NEAR
FREEZING.

THE FRONT WILL MOVE OFF TO THE EAST OVERNIGHT THURSDAY AND
NORTHWEST WINDS WILL USHER A RETURN OF COLD AND DRIER CONDITIONS.
HOWEVER...UPSLOPE SNOW SHOWERS ARE LIKELY ALONG AND WEST OF THE
ALLEGHENY FRONT.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL APPROACH FROM THE WEST FRIDAY WHILE LOW
PRESSURE INTENSIFIES OFF THE NEW ENGLAND COAST. THE UPPER-LEVEL
LOW ASSOCIATED WITH THE SURFACE LOW WILL REMAIN TO OUR NORTH...BUT
SHORTWAVE ENERGY WILL SWING THROUGH OUR AREA DURING THIS TIME. THE
PRESSURE GRADIENT BETWEEN THE LOW OFF NEW ENGLAND AND THE
APPROACHING HIGH WILL BE QUITE STRONG...RESULTING IN GUSTY WINDS.
WIND GUSTS AROUND 45 TO 50 MPH ARE POSSIBLE DURING THIS TIME.

THE GUSTY WINDS WILL CAUSE STRONG COLD ADVECTION AND THIS MAY
COMBINE WITH THE SHORTWAVE ENERGY TO BRING A FEW SNOW SHOWERS.
DO FEEL THAT THE AIRMASS WILL BE TOO DRY FOR ACCUMULATING SNOW
ACROSS MOST AREAS. HOWEVER...THERE MAY BE ENOUGH INSTABILITY FOR A
FEW BURSTS OF HEAVIER SNOW SHOWERS THAT COULD LEAVE A QUICK
COATING ALONG WITH REDUCED VISIBILITIES. THE BEST CHANCE FOR THIS
TO HAPPEN WOULD BE ACROSS NORTHERN MARYLAND INTO THE EASTERN
PANHANDLE OF WEST VIRGINIA...CLOSER TO THE SHORTWAVE ENERGY.

HIGH PRESSURE WILL BUILD OVERHEAD FRIDAY NIGHT AND GUSTY WINDS
FRIDAY EVENING WILL DIMINISH OVERNIGHT. HOWEVER...IT WILL BE QUITE
COLD WITH MIN TEMPS RANGING FROM THE SINGLE DIGITS IN NORTHERN
MARYLAND TO THE LOWER AND MIDDLE TEENS IN WASHINGTON AND
BALTIMORE. THE HIGH WILL REMAIN IN PLACE SATURDAY AND SATURDAY
NIGHT...BRINGING DRY AND COLD CONDITIONS.

LOW PRESSURE WILL LIKELY IMPACT THE AREA SUNDAY INTO
MONDAY...BRINGING THE NEXT SIGNIFICANT CHANCE FOR PRECIPITATION.
THIS SYSTEM MAY CUT TO OUR WEST UP THE APPALACHIANS...AND IF IT
DOES THERE WILL BE WARMER AIR THAT GETS DRAWN INTO THE
SYSTEM. THIS WOULD CAUSE RAIN OR A WINTRY MIX...DEPENDING ON HOW
MUCH LOW-LEVEL COLD AIR REMAINS IN PLACE. THESE DETAILS REMAIN
HIGHLY UNCERTAIN AT THIS TIME SO PLEASE STAY TUNED TO THE LATEST
FORECASTS FOR UPDATES.

HIGH PRESSURE WILL RETURN FOR THE MIDDLE PORTION OF NEXT WEEK WITH
DRY AND COLD CONDITIONS.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS EXPECTED TODAY INTO TONIGHT. CLOUDS WILL INCREASE
FROM WEST TO EAST ON THURSDAY. SUB-VFR CIGS AND VSBYS EXPECTED WITH
A LIGHT WINTRY MIX OF RAIN/SNOW AT LEAST FOR KMRB...KBWI...KMTN...
KIAD DURING THE DAY.

A COLD FRONT WILL PASS THROUGH THE TERMINALS THURSDAY NIGHT. GUSTY
NORTHWEST WINDS ARE EXPECTED FRIDAY INTO FRIDAY EVENING. GUSTS AROUND
40 KNOTS ARE POSSIBLE DURING THIS TIME. HIGH PRESSURE WILL BUILD
OVER THE TERMINALS LATER FRIDAY NIGHT THROUGH SATURDAY
NIGHT...CAUSING WINDS TO DIMINISH. LOW PRESSURE WILL LIKELY IMPACT
THE TERMINALS EARLY NEXT WEEK.

&&

.MARINE...
SOLID SMALL CRAFT CONDITIONS EXPECTED MUCH OF TODAY INTO TONIGHT. A
LOW PRESSURE SYSTEM WILL PASS BY TO THE NORTH ON THURSDAY. THE
GRADIENT IS EXPECTED TO TIGHTEN LATER IN THE DAY WITH SMALL CRAFT
CONDITIONS ONCE AGAIN EXPECTED THURSDAY MIDDAY THROUGH THE AFTERNOON
HOURS. SOME LIGHT RAIN/SNOW MAY ALSO BE POSSIBLE ESPECIALLY OVER THE
UPPER PORTION OF THE BAY WITH RAIN SOUTH.

A COLD FRONT WILL PASS THROUGH THE TERMINALS THURSDAY NIGHT. A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR THE WATERS.
STRONGER NORTHWEST WINDS ARE EXPECTED FRIDAY INTO FRIDAY NIGHT. A
GALE WARNING MAY BE NEEDED FOR THE WATERS DURING THIS TIME. HIGH
PRESSURE WILL BUILD OVERHEAD LATE FRIDAY NIGHT THROUGH SATURDAY
NIGHT. WINDS WILL DIMINISH. LOW PRESSURE WILL LIKELY IMPACT THE
WATERS EARLY NEXT WEEK.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ530>534-
     537>543.
     SMALL CRAFT ADVISORY FROM 1 PM TO 6 PM EST THURSDAY FOR
     ANZ530>534-538>543.
     SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ535-
     536.

&&

$$
UPDATE...GMS
PREV DISCUSSION...KRW/BJL








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