FXUS61 KLWX 070212
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
912 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 /UNTIL 6 AM MONDAY MORNING/...
SURFACE HIGH PRESSURE OVER THE AREA TONIGHT WILL MOVE OFF THE MID
ATLANTIC COAST AROUND SUNRISE. WATER VAPOR/INFRARED SATELLITE
IMAGERY INDICATED PLENTY OF HIGH/MID MOISTURE STREAMING THROUGH THE
CWA. WEST/SOUTHWEST FLOW ALOFT WILL KEEP A PIPELINE OF CIRRUS
ACROSS THE CWA OVERNIGHT...SO HAVE INCREASED SKY GRIDS ACROSS THE
CWA WHICH WILL DENOTE MOSTLY CLOUDY WORDING IN THE TEXT PRODUCTS.
CLOUDS WILL INHIBIT RADIATIONAL COOLING A LITTLE...BUT AIR MASS
REMAINS COLD AND EXPECT ANOTHER NIGHT OF GENERALLY LOWS IN THE
20S. WATCH FOR ANY PATCHES OF ICE THAT WOULD RESULT FROM ANY
RE-FREEZING OF MELTED SNOW/SLUSH.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM 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 /02Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS WILL PERSIST THROUGH THE VALID TAF PERIOD...AS A
DECK OF CIRRUS DRIFTS ACROSS THE CWA. LIGHT WINDS BECOME SOUTH 5
TO 8 KT ON MONDAY.
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...
HIGH PRESSURE MOVES EAST OF THE WATERS BY MONDAY...PROMOTING A
RETURN FLOW TO DEVELOP. SOUTH/SOUTHWEST WINDS EXPECTED AOB 10 KT
THROUGH MONDAY.
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.
&&
$$
SYNOPSIS...SBK/ABW
NEAR TERM...BPP
SHORT TERM...SBK
LONG TERM...ABW
AVIATION...BPP/ABW
MARINE...BPP/ABW
