000 
FXUS61 KLWX 220128
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
930 PM EDT WED SEP 21 2005

.UPDATE...
WATER VAPOR LOOP SHOWS RIDGING EXTENDING NORTHEAST FROM CENTRAL 
TEXAS...BEHIND A TROUGH WHICH IS NOW PUSHING OFF THE NORTH CAROLINA 
COAST. HURRICANE RITA CONTINUES TO TRACK WESTWARD INTO THE CENTRAL 
GULF OF MEXICO. ACARS 400-250MB WIND OBSERVATIONS INDICATE A 
125-140KT JET EXTENDS ALONG THE SOUTHERN CANADIAN BORDER. DIFFLUENCE 
IS OBSERVED ACROSS THE MID ATLANTIC...WHILE A 40-80KT JET EXTENDS 
FROM THE SOUTHWEST CONUS...THROUGH THE MIDDLE MISSISSIPPI RIVER 
VALLEY...AND INTO THE SOUTHEAST CONUS. 19Z SURFACE ANALYSIS 
INDICATES A 1020MB ANTICYCLONE MOVING INTO THE NORTHERN MID ATLANTIC 
REGION. A STATIONARY BOUNDARY EXTENDS FROM THE CAROLINAS NORTHWEST 
TO A 1005MB CYCLONE ACROSS EASTERN SOUTH DAKOTA.

SUBSIDENCE INVERSION NOTED ON THE 00Z KIAD RAOB AND LOCAL EVENING 
ACARS SOUNDINGS NEAR 6KFT HAS TRAPPED MOISTURE ACROSS THE SOUTHWEST 
ZONES. WILL WORD THESE ZONES AS PARTLY CLOUDY...WHILE ELSEWHERE 
RIDGING EXTENDING THROUGH THE COLUMN IS SUPPORTING PRECIPITABLE 
WATER VALUES NEAR A HALF INCH PER 00Z KIAD RAOB AND GOES/GPS DERIVED 
SENSORS...SUPPORTING CLEAR SKIES.

SURFACE ANTICYCLONE ACROSS THE FORECAST AREA IS ALREADY BEGINNING TO 
SHIFT ADVECTION REGIME FROM COLD TO WARM PER EAST-SOUTHEAST LOWER 
LEVEL WINDS ON KLWX VAD WIND PROFILE...LOCAL EVENING ACARS 
SOUNDINGS...AND 00Z KIAD RAOB. THUS AM EXPECTING LOWER LEVEL 
MOISTURE TO INCREASE THROUGH THE NIGHT...WHICH WILL PREVENT 
TEMPERATURES FROM FALLING MUCH BELOW 60 DEGREES (MID 60S DOWNTOWN 
CENTERS AND ALONG THE BAY). THE EXCEPTION MAY BE ACROSS THE NORTH 
CENTRAL FORECAST AREA WHERE THE DRIEST AIR HAS BEEN ENTRENCHED 
WITHIN THE ROLLING TOPOGRAPHY.

WITH MOISTURE INCREASING...WILL MAINTAIN MENTION OF LIGHT PATCHY 
FOG. LIGHT/VARIABLE WINDS WILL BE THE RULE OVERNIGHT WITH DECOUPLING 
TAKING PLACE...ALTHOUGH S/SE LIGHT FLOW MAY BE SUSTAINED IN LOCALS 
WHICH DECOUPLE THE LEAST.

WARM/MOIST ADVECTION QUICKLY RETURNS TOMORROW AS THE ANTICYCLONE 
SHIFTS OFF THE COAST...INCREASING HUMIDITY LEVELS AND CUMULUS 
DEVELOPMENT.

ALL UPDATED GRIDS/GRID DERIVED PRODUCTS/TEXT PRODUCTS HAVE BEEN 
RELEASED.

&&

.AVIATION...P6SM SKC WITH LIGHT AND VARIABLE WINDS OVERNIGHT. SOME 
MVFR FOG IS ALSO POSSIBLE. EXPECTING MORE CUMULUS DEVELOPMENT 
TOMORROW AS MOISTURE BEGINS TO INCREASE ACROSS THE REGION.

&&

.MARINE...VARIABLE WINDS LESS THAN 10KT OVERNIGHT WITH DIRECTION 
DICTATED BY A LAND BREEZE MORE SO THAN THE LOOSE SYNOPTIC GRADIENT. 
WATER LEVELS ARE CURRENTLY RUNNING ALMOST A HALF FOOT BELOW 
PREDICTED VALUES. THE LUNAR CYCLE IS WANING.  

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$

SHORT TERM/AVIATION/MARINE FORECASTER: ROGOWSKI