FXUS61 KLWX 260823
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
323 AM EST SAT DEC 26 2009
.SYNOPSIS...
LOW PRESSURE WILL SLOWLY MOVE NORTHEAST PAST THE MID ATLANTIC
TODAY AND THIS EVENING. THE LARGE STORM OVER THE CENTER OF THE
NATION WILL PULL NORTH OVER THE NORTHEAST STATES SUNDAY AND
MONDAY. COLD HIGH PRESSURE WILL MOVE OVER OUR REGION FOR THE FIRST
PART OF THE WORK WEEK. LOW PRESSURE DEVELOPS OVER THE CAROLINAS
THURSDAY.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
NOT MUCH CHANGE BETWEEN 230 AM AND 8 AM EXPECTED. CLOUDY SKIES
OVER THE ENTIRE AREA WITH LIGHT RAIN AND DRIZZLE OVER ALL BUT SOME
AREAS IN OUR SW FRINGE. TEMPS AND DWPTS WILL RISE MOST PROMINENTLY
IN S MD AS THE SURFACE LOW BUCKLES SOME WARMER AIR IN OVER OUR
FORECAST AREA.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 AM SUNDAY/...
CONDITIONS WILL BE SLOW TO IMPROVE TODAY...BUT CLEARING WILL BEGIN
TO MOVE SLOWLY ACROSS OUR AREA FROM SW AND W TO EAST. NOT
EXPECTING THE METRO DC AND BALTIMORE AREAS TO CLEAR UNTIL THIS
EVENING. E WINDS WILL GRADUALLY EASE AND BECOME W TODAY AND THIS
EVENING. SHOULD BE A GOOD TEMP GRADIENT ACROSS OUR AREA WITH S MD
AND THE W SHORE OF THE BAY REACHING THE MID 50S...WHILE THE SHEN
VALLEY REMAINING IN THE MID TO UPPER 30S. COOLER TEMPS AND MOSTLY
CLEAR OR CLEARING SKIES FOR ALL WITH TEMPS FALLING BACK INTO THE
MID 20S TO MID 30S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
SUNDAY...CLOSED/VERTICALLY STACKED UPPER LOW CONTINUES TO MOVE EAST
OVER THE GREAT LAKES. CCW FLOW BRINGS COLD AIR TOWARDS THE MID
ATLANTIC...THOUGH DRY WLY/DOWNSLOPING FLOW TO KEEP AREAS EAST OF THE
APPALACHIANS ABOVE NORMAL...MAX TEMPS UPPER 40S...AROUND 50F SRN MD.
SUNDAY NIGHT AND MONDAY...UPPER VORTEX CROSSES PA WITH NWLY FLOW
BRINGING UPSLOPE SNOW TO WESTERN SLOPES OF THE ALLEGHENY FRONT WHICH
COULD SEE A FEW QUICK INCHES OF FRESH SNOW /AN ADVISORY MAY BE
NECESSARY/. ANTICIPATE AN EMBEDDED S/W TO HAVE ENOUGH STRENGTH OF
BRING SOME SNOW SHOWERS EAST ACROSS THE NORTHERN HALF OF THE
CWA...CHANCE POPS ACROSS WESTERN/NORTH-CENTRAL MARYLAND... THE
EASTERN WEST VIRGINIA PANHANDLE...AND NORTHERN VIRGINIA /SCHC FOR
DC/. NORTH CENTRAL VIRGINIA/SOUTHERN MARYLAND IN LEE OF HIGHER WV
RIDGES...EXPECT EXTRA DOWNSLOPING TO DISSIPATE ANY SHOWERS.
TUESDAY AND WEDNESDAY...CANADIAN AIR CROSSES THE AREA WITH BUILDING
SURFACE HIGH PRESSURE. DECREASING TREND IN MIN TEMPS STARTING MONDAY
MORNING BECOMES BELOW NORMAL BY WEDNESDAY MORNING WHEN COLD DOME IS
CENTERED OVER THE AREA... 15 TO 20F MINS SHOULD BE COMMON ACROSS
INLAND AREAS.
EXTENDED...THE ACTIVE PATTERN IN THE SOUTHERN STREAM CONTINUES NEXT
WEEK WITH ANOTHER WAVE CROSSING THE SOUTHERN PLAINS MID WEEK WITH
CYCLOGENESIS OVER THE CAROLINAS IN THE THURSDAY/FRIDAY TIMEFRAME.
STAY TUNED FOR DETAILS ON ANOTHER SHOT OF WINTRY PRECIPITATION.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
LOW CIGS AND VSBYS WILL BE SLOW TO EASE TODAY. CHO AND THEN MRB
SHOULD BE THE FIRST TO BREAK THIS AFTERNOON...THE REST WILL PROB
NOT BREAK UNTIL EVENING. AFTER THAT...THERE MAY BE SOME FOG AT
CHO TONIGHT...BUT NOT EXPECTING IT AT THE OTHER TAF SITES.
AN UPPER LOW MOVES NORTH OF THE AREA SUNDAY NIGHT...BRINGING PERHAPS
SOME PASSING SNOW SHOWERS TO THE BALT-WASH METRO TERMINALS LATE IN
THE NIGHT/EARLY MONDAY MORNING.
VFR CONDITIONS PREVAIL IN WLY FLOW MONDAY THROUGH MIDWEEK UNDER
BUILDING HIGH PRESSURE. WLY WINDS COULD BE GUSTY /25 TO PERHAPS 30
KT/ WITH INCREASING PRESSURE GRADIENT. THE NEXT STORM SYSTEM
APPROACHES THE MID ATLANTIC LATE NEXT WEEK.
&&
.MARINE...
STRONG EAST WINDS ARE BEGINNING TO EASE EARLY THIS MORNING...BUT
SMALL CRAFT CONDITIONS WILL LAST UNTIL 11Z ON THE MIDDLE AND UPPER
POTOMAC...AND UNTIL 17Z ELSEWHERE.
UPPER LOW CROSSES PENNSYLVANIA SUNDAY NIGHT WITH INCREASING GRADIENT
BRINGING SCA CRITERIA WINDS BY MONDAY MORNING. MARINE HEADLINES FOR
WINDS THE CONTINUE INTO WEDNESDAY AS HIGH PRESSURE CROSSES THE AREA.
DO NOT SEE GALES ATTM...ONLY STRONG SCA. THE NEXT STORM SYSTEM
APPROACHES THE MID ATLANTIC LATE NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
HIGHER THAN NORMAL TIDES...THANKS TO PERSISTENT EASTERLY FLOW
PRODUCED SOME MINOR TIDAL FLOODING IN THE DC AREA AND CAME CLOSE
ALONG THE BAY. ALTHOUGH THE EASTERLY FLOW WILL BEGIN TO RELAX
DURING THE DAY TODAY...THE HIGH TIDE DURING THE DAYLIGHT HOURS IS
THE HIGHER OF THE TWO HIGH TIDES. FOR ALL OF THOSE REASONS...A
TIDAL/COASTAL FLOOD ADVISORY WAS ISSUED THRU 3PM TODAY FOR MINOR
TIDAL FLOODING NEAR TIMES OF HIGH TIDES.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
DCZ001.
MD...COASTAL FLOOD ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
MDZ007-011-013-014-016>018.
VA...COASTAL FLOOD ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
VAZ052>055-057.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST TODAY FOR ANZ530>534-
537>543.
SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
ANZ535-536.
&&
$$
SYNOPSIS...CAS/BAJ
NEAR TERM...CAS
SHORT TERM...CAS
LONG TERM...BAJ
AVIATION...BAJ/CAS
MARINE...BAJ/CAS
TIDES/COASTAL FLOODING...CAS
