000 
FXUS61 KLWX 020222
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
920 PM EST TUE MAR 1 2005

UPDATE...
AM OPTING NOT TO DO AN UPDATE TO THE ZNS. THINK THESE ARE 
REPRESENTATIVE OF WHATS GOING TO OCCUR OVRNGT. AREA WL REMAIN IN 
CYCLONIC FLOW...E OF THE MTNS SKIES WL BE PC. ALONG WRN RDGS OF 
HIGHLANDS IS A DIFFERENT STORY DUE TO UPSLOPE SNSH. 

EOL AND CWF HV ALREADY BEEN SENT. WSW FOR HIGHLANDS WL BE UPDATED BY 
10 PM.

WOODY

.SHORT TERM (TONIGHT THROUGH WEDNESDAY)...


WATER VAPOR LOOP SHOWS AN UPPER LOW OVER THE CENTRAL APPALACHIANS 
WITH AN EMBEDDED WAVE CROSSING THE FORECAST AREA. ACARS 400-250MB 
WIND OBSERVATIONS REVEAL A 130-150KT UPPER LEVEL JET CURVES FROM THE 
MIDDLE MISSISSIPPI RIVER VALLEY THROUGH THE SOUTHEAST CONUS. 12Z 
SURFACE ANALYSIS PLACES THE 993MB PARENT CYCLONE EAST OF 
DETROIT...WITH THE COASTAL 987MB CYCLONE NEAR THE MAINE WATERS. COLD 
FRONTS ARE PLACED ALONG THE SPINE OF THE APPALACHIANS...AND ACROSS 
THE MIDWEST. A LEE TROUGH PROCEEDED THE FIRST COLD FRONT.

HAVE EXTENDED THE WINTER STORM WARNING FOR THE WESTERN PORTION OF 
THE WESTERN 5 COUNTIES. WITH THE PASSAGE OF THE SECONDARY COLD 
FRONT...A SECOND SHOT OF COLD ADVECTION HAS ENHANCED THE UPSLOPE 
SNOW. LOW LEVEL LIFT WITHIN THE DENDRITIC TEMPERATURE LAYER WILL 
CREATE EFFICIENT SNOW TOTALS. MODERATE SNOWS WILL RESULT IN 
STREAMERS WEST OF THE ALLEGHENY FRONT.

TIGHT HEIGHT GRADIENT WILL ALLOW FOR WIND GUSTS OF 30 TO 40 MPH 
WITHIN THE HIGHEST TERRAIN OVERNIGHT...CAUSING BLOWING SNOW AND WIND 
CHILLS NEAR ZERO.

CLOUDS EAST OF THE MOUNTAINS MAY TEND TO ERODE WITH LOSS OF DIURNAL 
HEATING WITH DOWNSLOPE EFFECT...DESPITE UPSTREAM MOISTURE SOURCE. 

WITH UPPER LOW SLOWLY MOVING ALONG...EXPECTING A SIMILAR DAY 
WEDNESDAY. DIURNAL CLOUDS WILL DEVELOP DURING THE LATE 
MORNING...WHILE WINDS GUST TO 30 MPH (40 MPH HIGHER TERRAIN) USING 
NAM/GFS BUFKIT MOMENTUM TRANSFER VALUES.

HEIGHT RISES WILL ENCOURAGE A LOWERING CEILING AND HENCE A LESS 
EFFICIENT UPSLOPE SNOW PROCESS WEDNESDAY.

&&

.AVIATION...INVERSION SHOULD SUPPORT SCT-BKN MIDLEVEL CLOUDS 
OVERNIGHT...BUT THEY WILL TEND TO SCOUR WITH LOSS OF SUNSHINE. 
PRESSURE GRADIENT WILL SUPPORT GUSTY WINDS...ESPECIALLY THIS EVENING 
AND TOMORROW. CLOUDS WILL TEND TO BUILD DURING THE LATE MORNING...A 
BIT LOWER DUE TO THE LOWERING INVERSION.

&&

.MARINE...WILL KEEP THE SMALL CRAFT ADVISORY. WINDS ARE NEAR AND 
JUST ABOVE SMALL CRAFT CRITERIA. WINDS EXPECTED TO INCREASE 
WEDNESDAY WITH MIXING...WITH A POTENTIAL TO MIX DOWN 30 KT. WINDS 
WILL CONTINUE IN SMALL CRAFT RANGE THROUGH WEDNESDAY NIGHT...AND 
THEN SUBSIDE A PINCH /AT LEAST BELOW CRITERIA/ THURSDAY.

WATER LEVELS ARE RUNNING ABOUT A FOOT ABOVE NORMAL ACROSS THE BAY.
&&

.LONG TERM...
STRONG POSITIVE PNA PATTERN LOCKED IN BY OMEGA BLOCK OVER NORTH ATL 
WILL PERSIST THROUGH NEXT WEEK RESULTING IN COLDER THAN NML MAINLY 
DRY PTTN OVER MID ATL.  CLIPPER SYSTEMS IN NW FLOW ALOFT WILL PASS 
THROUGH ABOUT EVERY OTHER DAY BUT EFFECTS WILL BE MAINLY CONFINED 
NORTH OF MASON DIXON LINE AND ALONG WRN SLOPES OF CWA AS BROAD 
LONGWAVE TROF PRECLUDES ANY CHC FOR SYSTEMS TO SHARPEN FAR ENOUGH 
SOUTH TO PRODUCE SIG PCPN EAST OF THE RDGS.  ALSO NOT CONFIDENT IN 
MODEL TIMING AND AMPLITUDE OF INDIVIDUAL SHTWVS BUT RAISED 
CLOUDINESS AND POPS SAT AND MON BASED ON CURRENT TRENDS. 
&&


.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER STORM WARNING FOR MDZ002 UNTIL 5 AM WEDNESDAY.
VA...WINTER STORM WARNING FOR VAZ021 UNTIL 5 AM WEDNESDAY.
WV...WINTER STORM WARNING FOR WVZ048-049-054 UNTIL 5 AM WEDNESDAY.
MARINE...SMALL CRAFT ADVISORY FOR THE TIDAL POTOMAC AND THE MARYLAND 
         PORTION OF THE CHESAPEAKE BAY.

&&

$$

SHORT TERM/AVIATION/MARINE...ROGOWSKI/JB
LONG TERM...PS