Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 271440
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
940 AM EST FRI FEB 27 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVERHEAD THROUGH SATURDAY. THE HIGH WILL
MOVE OFF THE COAST SUNDAY AND ANOTHER COLD FRONT WILL PASS THROUGH
THE AREA SUNDAY NIGHT. A WARM FRONT AND LOW PRESSURE WILL CROSS
THE AREA TUESDAY AND WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT WILL DROP SOUTH OF SOUTHERN MARYLAND BY NOON. ANY
LEFTOVER LIGHT SNOW OR FLURRIES WILL TAPER OFF BY THEN. HIGH
PRESSURE WILL APPROACH FROM THE OHIO VALLEY BEHIND THE COLD FRONT
FOR THIS AFTERNOON. A NORTHWEST FLOW AHEAD OF THE HIGH WILL USHER
IN COLD CONDITIONS. IN FACT...TEMPERATURES WILL HOLD NEARLY STEADY
TODAY IN THE 20S AND LOWER 30S.

THERE IS A LITTLE INSTABILITY IN THE FORECAST SOUNDINGS DUE TO THE
COLD ADVECTION. HOWEVER...THERE IS NOT MUCH IN THE WAY OF SYNOPTIC
LIFT. THEREFORE...A FEW FLURRIES ARE POSSIBLE THIS AFTERNOON BUT
NO SNOW ACCUMULATION IS EXPECTED FOR LOCATIONS EAST OF THE
ALLEGHENY HIGHLANDS. LIGHT SNOW ACCUMULATIONS ARE POSSIBLE ALONG
AND WEST OF THE ALLEGHENY FRONT DUE TO AN UPSLOPE FLOW.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
A SPRAWLING AREA OF HIGH PRESSURE IN THE CENTRAL CONUS WL BE WORKING
EWD TNGT-SAT. CLDS WL BECOME MORE SCARCE AS SUBSIDENCE INCREASES.
THERE IS DCPLG POTL TNGT. IF THAT OCCURS...THEN TEMPS CUD TUMBLE. HV
NOT REFLECTED THAT IN DATABASE /AM HOLDING ONTO 5 KT WIND/...BUT IF
FCST WERE TO GO ASTRAY...THATS MOST LKLY WHERE. AM USING MOS MEAN...
WHICH YIELDS MIN-T BTWN MID SINGLES WEST TO MID TEENS EAST.

CORE OF COLD AIR WL BE OVER/JUST N OF CWFA SAT...SPCLY IN THE MRNG.
THUS...THIS WL BE THE COLDEST DAY BEFORE REBOUND OCCURS. MAXT INTHE
20S EVERYWHERE. FURTHER...THINK THERE WL BE ENUF MSTR IN THE COLUMN
FOR AT LEAST PTCLDY SKIES.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE WILL BE LOCATED ACROSS NEW ENGLAND AND THE MID-
ATLANTIC SATURDAY NIGHT WHILE A JET STREAK MOVES NORTHWARD INTO THE
MID-WEST. LOW PRESSURE WILL INTENSIFY ACROSS THE CENTRAL PLAINS AS A
SHORTWAVE TROUGH DROPS INTO THE NRN PLAINS SUNDAY. WARM AIR
ADVECTION AHEAD OF THE SYSTEM WILL BRING GULF AND ATLANTIC MOISTURE
INTO THE MID-ATLANTIC SUNDAY AFTERNOON. PRECIPITATION IS EXPECTED TO
MOVE INTO THE POTOMAC HIGHLANDS SUN MORNING AND SPREAD EASTWARD.
PWATS ARE EXPECTED TO DOUBLE DURING THE DAY. HIGH PRESSURE IS
EXPECTED TO KEEP COLD AIR IN PLACE ACROSS THE MID-ATLANTIC LEADING
TO SUB FREEZING TEMPERATURES AS PRECIPITATION MOVES INTO THE REGION.
WINDS ARE EXPECTED TO BECOME SOUTHERLY SUNDAY MORNING BUT LIGHT AND
WARM AIR ADVECTION WILL LIKELY BE SLOW UNTIL WINDS INCREASE...WHICH
MAY NOT HAPPEN DURING THE DAY. IF THAT IS THE CASE...TEMPS WILL BE
SLOWER TO RISE AND AREAS ACROSS CENTRAL VA MAY SEE A PERIOD OF
WINTRY PRECIPITATION. GUIDANCE SHOWS TEMPS RISING ABOVE FREEZING
SUNDAY IN THIS AREA BUT DUE TO THE LIGHT WINDS LEFT A CHANCE OF
IP/ZR ACROSS THE ENTIRE AREA. PRECIPITATION IS EXPECTED TO BEGIN AS
SNOW BUT THEN SWITCH TO IP/ZR BY SUNDAY AFTERNOON. THE BEST CHANCE
OF IP/ZR AND LIGHT ICE ACCUMULATION WILL BE FURTHER NORTH NEAR THE
MD/PA BORDER WHERE SFC TEMPS WILL STAY NEAR OR BELOW FREEZING DURING
THE DAY AND POSSIBLY INTO THE EVENING. AREAS SOUTH OF DC MAY NOT SEE
MUCH QPF AS MUCH OF THE FORCING IS FURTHER NORTH HOWEVER...MOISTURE
ADVECTION WILL LIKELY LEAD TO A PERIOD OF RA/IP/ZR.

A COLD FRONT MOVES THROUGH THE REGION SUNDAY NIGHT AND DRY
CONDITIONS ARE EXPECTED MONDAY WITH THE EXCEPTION OF UPSLOPE SN/RA
SHOWERS ALONG THE WESTERN SLOPES. HIGH PRESSURE MOVES INTO THE
REGION MONDAY NIGHT AND TUESDAY. A COLORADO LOW WILL DEVELOP EARLY
NEXT WEEK AND TRACK ACROSS THE CENTRAL PLAINS AND EVENTUALLY THE
GREAT LAKES. ANOTHER ROUND OF WARM AIR ADVECTION WILL BUILD INTO THE
REGION TUESDAY. COLD SURFACE TEMPS WILL PERSIST ACROSS THE MID-
ATLANTIC AND ANOTHER ROUND OF ICING IS POSSIBLE TUESDAY NIGHT INTO
WEDNESDAY BEFORE A WARM FRONT PASSAGE. THIS WARM FRONT WILL BRING
MUCH RELIEF TO THE MID-ATLANTIC WITH TEMPERATURES FORECAST IN THE
50S TO NEAR 60 BY WED AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE
REGION BY THURSDAY AND TEMPS WILL LOWER TO NEAR NORMAL.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS ARE EXPECTED TODAY. A FEW FLURRIES CANNOT BE RULED
OUT. NORTHWEST WINDS WILL GUST AROUND 15 TO 20 KNOTS.

WINDS SHUD RELAX AND CLDS SLOWLY SCATTER OUT TNGT. LGT WNDS AND SCT
CLDS WL CARRY INTO SAT.

A WINTRY MIX IS POSSIBLE SUNDAY AFTERNOON AT THE TERMINALS AND
MVFR/IFR CONDITIONS ARE LIKELY AS PRECIPITATION MOVES INTO THE
REGION. ANOTHER ROUND OF WINTRY MIX IS POSSIBLE TUESDAY AND
TUESDAY NIGHT.

&&

.MARINE...
NORTH TO NORTHWEST WINDS ARE EXPECTED BEHIND A COLD FRONT TODAY. A
SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS DURING THIS TIME.
WL CONT ADVY FOR TNGT...BUT HV PULLED BACK N OF POOLES ISLAND.

HIGH PRESSURE WILL PERSIST ACROSS THE AREA SATURDAY NIGHT
BEFORE MOVING OFF THE COAST SUNDAY. SCA CONDITIONS ARE POSSIBLE
SUNDAY NIGHT INTO MONDAY AHEAD AND BEHIND A FRONTAL PASSAGE.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST SATURDAY FOR ANZ531>534-
     537-539>541-543.
     SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ530-
     535-536-538-542.

&&

$$
SYNOPSIS...BJL/HTS
NEAR TERM...BJL/HTS
SHORT TERM...HTS
LONG TERM...HAS
AVIATION...BJL/HAS/HTS
MARINE...BJL/HAS/HTS


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