AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
AFDLWX 959 AM EST SUN FEB 22 2004
.UPDATE...MSTR AT H9 CAUGHT UNDER INCRSG SUBSIDENCE INVSN.
UNFORTUNATELY IAD/RNK SNDGS BOTH INOP...BUT INVSN SHOWS UP WELL ON
ACARS DATA. GOOD MIXING BLO INVSN. SO...ONCE AGN A BATTLE OF
DWNSLOPE VS ADVECTION. DUE TO STEEPNESS OF INVSN...WL SIDE A LTL
MORE PESSIMISTICALLY...INCRSG CLDS AND DECRSG MAXT. AREAS NEAR BAY
AND LWR PTMC OK AND WONT BE AFFECTED BY THESE CHGS. EVERYTHING ELSE
ON TRACK. -HTS
&&
.PREV DISCUSSION...
.SHORT TERM...
FAIRLY QUIET IN THE SHORT TERM. MIDLEVEL FLOW OVER THE REGION IS
BASICALLY FLAT WITH HIGH PRESSURE AT THE SURFACE.
GUSTY SURFACE WINDS WILL CONTINUE TO DECREASE THIS MORNING AS THE
GRADIENT RELAXES. PREVIOUS SHIFT WAS ABLE TO DROP THE SCA FOR THE
MARINE ZONES. OTHERWISE IT WILL BE A CLOUD AND TEMP FORECAST DAY.
LOW LEVEL MOISTURE HANGS IN UNTIL MID DAY BEFORE SCOURING OUT. MAV
AND MET TEMPS LOOK REASONABLE GIVEN THE DECREASING CLOUDS AND HIGH
SUN ANGLE. DECREASING AFTERNOON CLOUDS WILL MAKE FOR MOSTLY CLEAR
SKIES EARLY TONIGHT. HIGH CLOUDS WILL INCREASE AGAIN LATE AHEAD OF
THE NEXT FAST MOVING NORTHERN STREAM SYSTEM.
&&
.LONGER TERM...
MON...LOOKS CLOUDY AS MID-HIGH LVL MOISTURE ADVANCES AHEAD OF NRN
STREAM SHORTWAVE. STILL DRY.
MON NIGHT-TUE...MODELS DIFFER IN TIMING OF POTENTIAL PRECIP. WEAK
WARM ADVECTION AHEAD OF DIVING S/W IN THE NRN STREAM TO RESULT IN
SCT LIGHT PRECIP SOMETIME DURING THIS TIME FRAME. GFS IS FASTER
BRINGING PRECIP ACROSS THE AREA AROUND 00Z TUE WHILE ETA/UKMET MORE
AFTER 06Z TUE. FOLLOWED HPC QPF GRAPHIC HERE BRINGING A CHANCE TO
NWRN QUARTER OF CWA AFTER 06Z TUE. PRECIP TYPE LOOKS TO BE RAIN.
LOOKS LIKE A BETTER CHANCE NOW FOR SOME PRECIP DURING THE DAY ON TUE
AS S/W TROUGH AND ASSOCIATED CDFNT CROSSES THE AREA. IN FACT LATEST
MAV SUGGEST LIKELY POPS TUE. ETA AND UKMET SUGGEST CHANCE POPS TOO.
PRECIP TYPE LOOKS A BIT PROBLEMATIC AS GFS SUGGESTS ALL LIQUID WHILE
ETA AND UKMET SUGGEST SOME SNOW OVER THE ERN HALF OF THE CWA. AT ANY
RATE SYSTEM IS A QUICK MOVER WITH LOW QPF AND GROUND TEMPS ARE
PRETTY WARM DUE TO RECENT WARM SPELL. SO NOT ANTICIPATING ANY
ACCUMS.
WED-SAT...LATEST MEDIUM RANGE GUIDANCE NOW KEEP SRN STREAM SYSTEM
WELL TO THE SOUTH OF DCA WITH PRECIP FROM THIS SYSTEM OVR FAR SRN VA
AND NC. 00Z GFS NOW SUGGESTS A SUNNY DAY BOTH WED AND THU. KEPT A
LOW CHANCE POPS FOR WED DUE TO POOR CONTINUITY IN MODELS. WILL LET
DAYSHIFT TAKE A LOOK AT ONE MORE MODEL RUN BEFORE COMPLETELY
REMOVING POPS. HOWEVER DID TRENDED A BIT MORE OPTIMISTIC IN SKY CVR
AND LOWERED POPS. ALSO RAISED MAXT A BIT WED/THU GIVEN MORE SUNSHINE
EXPECTED.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
CPW/ROSA