FXUS61 KLWX 061930
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
230 PM EST SUN DEC 6 2009
.SYNOPSIS...
HIGH PRESSURE PASSES OVER THE AREA TONIGHT AND CONTINUES TO DOMINATE
MONDAY. LOW PRESSURE WILL TRACK INTO MICHIGAN TUESDAY NIGHT. A
COMPLEX FRONTAL SYSTEM WILL EXTEND FROM IT INTO THE MID ATLANTIC
STATES TUESDAY NIGHT AND WEDNESDAY. HIGH PRESSURE WILL RETURN FOR
THURSDAY AND FRIDAY.
&&
.NEAR TERM /TONIGHT/...
HIPRES CNTRD OVR SW CWA THIS AFTN WILL MOVE E ACRS THE REGION TNGT.
DESPITE CALM WINDS AND SNOW COVER...DENSE CI FIELD CURRENTLY
ENCOMPASSING MUCH OF DEEP SOUTH TO MS VLY WILL RACE ENEWD OVR MID
ALTC...INHIBITING IDEAL RADIATIONAL COOLING. DECIDED TO NOT UNDERCUT
TEMP GUIDANCE OVNGT AND WENT WITH A MAV/MET BLEND FOR MINIMA...WHICH
WILL STILL PUT MRNG LOWS IN THE 20S MOST AREAS...WITH UPR TEENS W OF
BLUE RIDGE. INVRN BCMS ESTABD TNGT AS SW WINDS AT 850MB ADVECTS
WARMER TEMPS ALOFT.
&&
.SHORT TERM /MONDAY/...
MID/HIGH LEVEL MOISTURE INCRS MON AS SHRTWV PASSING ACRS GREAT LAKES
INTO NEW ENGLAND SENDS MID LEVEL TROF ACRS THE AREA. WHERE
OROGRAPHIC FEATURES AID LIFT WEST OF ALLEGHENY FRONT...WONT RULE OUT
LGT RN/SN MIX MON AFTN...WHERE LOW POPS HAVE BEEN INTRODUCED. A BIT
WARMER TOMORROW...BUT MAXIMA STILL AROUND 5 DEGREES BELOW
AVERAGE...WITH 40S XPCD MOST AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
MID ATLC WX IN THE WK AHD MAY BE SUMMED UP BY BY "A COMPLEX MIDWK
LOW PRESSURE SYSTEM SURROUNDED BY HIGH PRES ON EITHER SIDE."
ACTUALLY AFTR HIGH PRES MOVES OFF THE CST MON A SHORT WV TO THE N WL
BE PUSHING THROUGH QUICKLY ON A 125 KT JET. ONLY SENSIBLE WX MAY BE
UPSLOPE SNSH IN THE FAR W. A SEASONABLY COOL NGT W/ LOWS RANGING FM
THE L30S ALONG THE BAY TO A20 IN THE HIGHLANDS.
HIGH PRES RETURNS FOR TUE. TEMPS IN LM40S XCPT U30S FAR W. THEN TUE
NGT WL BECOME MESSY/COMPLICATED AS DEEPENING LOW PRES OVR MO TRACKS
INTO IL/MI. A WARM FNT WL BE S OF THE AREA..AND IT LOOKS LK THERE
WL BE A PD TUE NGT OF RAIN FALLING INTO SUBFRZG AIR. HV UPPED POPS
TO CATEGORICAL. QUSTNS ARE HOW LONG WL IT TAKE FOR COLD AIR TO
ERODE...HOW FAR E WL SUBFRZG AIR BE ABLE TO GET TUE NGT..AND HOW
MUCH QPF ARE WE XPCTG?
FOR NOW... I THINK QPF OF BTWN .5 AND 1.0" IS CERTAINLY IN THE REALM
OF BELIEVABILITY. I'M GOING TO KEEP BALT/DC PROPER OUT OF THE
SUBFRZG LAYER TUE NGT. IF THIS WERE JAN STORY MIGHT BE DIFFERENT.
HOWEVER FM RT 15 W IN THE SHEN VALLEY THINK PTNL FOR SIG ICING IS
PSBL..AND THERE MAY BE A THIN AREA W OF I-95 OF ZR CHANGING TO RA.
IT'S NEAR IMPOSSIBLE TO FCST THE TIMING OF EROSION OF THE SUBFRZG
LYR THIS FAR OUT...BUT SOMETIME WED MRNG..ALTHO WE'VE SEEN THAT CD AIR
CAN BE VERY DIFFICULT TO DISLODGE..ESPECIALLY FM FREDERICK VA N TO
THE PA BORDER. IT IS TOO EARLY TO CONSIDER WATCHES - IN FACT WE'VE
GOT ANOTHER 24 HRS TO CONTEMPLATE THAT.
HIGH PRES LOOKS TO RETURN WED AFTN THRU TO FRI. LOW PRES MAY TRACK S
OF THE AREA NEXT WKND WHICH WL HV TO BE WATCHED.
&&
.AVIATION /TONIGHT THROUGH FRIDAY/...
VFR CONDS THRU NEXT 30 HRS AS HIPRES DOMINATES. SCT/BKN 20KFT CI
WILL CONT...LOWERING TO 10-15 KFT AFTER DAYBREAK MON. LIGHT MOSTLY N
WINDS THIS EVE BCM CALM OVNGT...THEN LGT AND SLY TMRW.
VFR CONDS AT TAF SITES MON NGT AND TUE. NEXT SYSTEM WL BE TUE NGT
AND WED WHICH WL HV PTNL TO CAUSE ICING/POOR CIGS AND VSBY.
&&
.MARINE...
WITH HIPRES ADVANCING TOWARD THE WATERS THIS EVE...N WINDS SHUD RMN
AOB 10 KTS THRU ERY TNGT. SFC RIDGE PUSHES INTO ATLC TMRW...BRINGING
LGT SLY WINDS TO THE WATERS.
NO PROBS ON WATERS MON NGT OR TUE. NEXT SIGNIFICANT SYSTEM WL BE TUE
NGT AND WED.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
PRODUCTS...SBK/WOODY!
