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000
FXUS61 KAKQ 100105
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
805 PM EST MON DEC 9 2013

.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN NEARLY STATIONARY FROM CENTRAL NORTH
CAROLINA TO SOUTHEAST VIRGINIA OVERNIGHT. LOW PRESSURE WILL TRACK
NORTHEAST ALONG THE BOUNDARY LATER TONIGHT INTO TUESDAY. A COLD
FRONT SWEEPS THROUGH THE REGION LATER TUESDAY AFTERNOON. HIGH
PRESSURE BUILDS IN FROM THE NORTHWEST TUESDAY NIGHT AND
WEDNESDAY...BRINGING COOL AND DRY CONDITIONS TO THE REGION.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THE LATEST WATER VAPOR IMAGERY AND REGIONAL RADAR MOSAIC INDICATE A
MOIST FRONTAL BAND EXTENDING FROM CENTRAL NC TO SE VA. SOME
MID/UPPER DRYING HAS ENTERED EASTERN WV/WESTERN VA EVIDENCED BY
WATER VAPOR AND VISIBLE IMAGERY. THIS GENERAL TREND SHOULD CONTINUE
THROUGH THE EVENING AND EARLY OVERNIGHT HOURS...WITH PERIODS OF RA
SE...AND MAINLY DRY CONDITIONS NW. LATER TONIGHT...A VIGOROUS TROUGH
(PRESENTLY DIVING SE ACROSS THE NORTHERN PLAINS) WILL REACH THE
MIDWEST. THIS WILL ALLOW THE MOIST FRONTAL BAND TO LIFT
NORTHWARD...AND ACCORDINGLY POPS INCREASE ACROSS MOST OF THE AREA
(ASIDE FROM THE LOWER MD EASTERN SHORE) LATER TONIGHT. TEMPERATURES
SHOULD REMAIN STEADY IN THE MID/UPPER 40S SE OVERNIGHT...WHILE LOWS
SHOULD REACH THE LOW/MID 30S NW...BUT EVENTUAL MINIMA WILL DICTATED
BY WHETHER OR NOT THE LOW CLOUDS SCOUR OUT FOR A PERIOD OF TIME.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
THE AFOREMENTIONED TROUGH GENERATES A POWERFUL 180KT (GEOSTROPHIC
WIND) 300MB JET...THAT RACES ENE ACROSS THE OHIO VALLEY TUESDAY
MORNING. THIS INDUCES A BAND OF STRONG FRONTOGENESIS ACROSS THE MID
ATLANTIC TUESDAY MORNING ALONG WITH ROBUST UPWARD VERTICAL MOTION.
ADDITIONALLY...THERE IS DECENT MOISTURE ADVECTION AHEAD OF THE
TROUGH. MODEL CROSS-SECTIONS (NAM/GFS) INDICATE A RATHER CLASSIC
SLOPING FRONTAL ZONE WITH STRONG FRONTOGENESIS FROM THE SURFACE TO
AROUND 600MB. IN ADDITION...NEUTRAL THETA-E LAPSE RATES INDICATE A
POTENTIAL FOR SYMMETRIC INSTABILITY. ALL THIS COMBINED SUPPORTS THE
POTENTIAL FOR HEAVY BANDED PRECIPITATION ACROSS THE MID-ATLANTIC
REGION.

AT THIS TIME...THE STRONGEST BAND APPEARS TO SET-UP NEAR THE
NORTHERN PORTION OF THE AKQ CWA. GIVEN THE STRENGTH OF THE
SYSTEM...THERE SHOULD BE LITTLE DIFFICULTY CHANGING THE PRECIP OVER
TO SNOW (DRIVING SURFACE TEMPS TO THE WET-BULB...WHICH ARE AROUND
30-32F)...BUT THERE COULD BE A MIX WITH SLEET EARLY DUE TO RESIDUAL
MID-LEVEL WARM AIR. SNOW AMOUNTS SHOULD RANGE FROM 1-3IN ACROSS THE
FAR N (LOCALIZED AMOUNTS AROUND 4 ARE POSSIBLE)...AND TAPERING TO AN
INCH OR LESS IN VICINITY OF A LINE FROM FVX-RIC-WAL. AN ADVISORY HAS
BEEN RAISED FOR THE NORTHERN PORTION OF THE AREA.

DRIER AIR QUICKLY COMES IN FROM THE WEST DURING THE AFTERNOON AND
THIS SHOULD BRING A QUICK END TO PRECIPITATION. HIGH PRESSURE
FINALLY BUILDS IN FROM THE NW TUESDAY NIGHT INTO THURSDAY BRINGING
DRIER BUT VERY COLD CONDITIONS. LOWS TUESDAY/WEDNESDAY NIGHT SHOULD
RANGE FROM THE UPPER TEENS TO LOW 20S NW...TO THE LOW 30S NC
COAST...WITH HIGHS WEDNESDAY/THURSDAY ONLY IN THE UPPER 30S TO LOWER
40S FOR MOST AREAS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
12Z GFS AND 12Z ECMWF IN GENERALLY GOOD AGREEMENT FOR THE EXTENDED
PERIOD...WITH TEMPS EXPECTED TO REMAIN AT OR BELOW NORMAL. DRY WX
WILL PREVAIL ACRS THE REGION FM THU NGT THRU FRI EVENG...AS HI PRES
BLDS OVR THE REGION THEN OFF THE CST. LO PRES WILL THEN TRACK FM THE
LWR MS VLY LATE FRI NGT...NE TO THE SRN NEW ENGLAND CST BY SUN MORNG.
THIS LO AND AN ASSOC COLD FRONT WILL BRING GOOD CHCS FOR RAIN SAT
INTO EARLY SUN MORNG. THE PCPN WILL END OVR SE CNTIES SUN MORNG...AS
THE FRONT PUSHES OUT TO SEA SUN AFTN. THE PCPN COULD END AS A FEW
SNOWFLAKES ACRS THE NW CNTIES LATE SAT NGT INTO EARLY SUN MORNG. HI
PRES WILL RETURN FOR LATER SUN THRU MON. MIN TEMPS WILL RANGE FM THE
UPR TEENS TO MID 20S FRI MORNG...IN THE UPR 20S TO LWR 30S SAT
MORNG...IN THE LWR 30S TO LWR 40S SUN MORNG...AND IN THE 20S TO LWR
30S MON MORNG. MAX TEMPS WILL BE IN THE LWR TO MID 40S FRI...RANGE
FM THE MID 40S TO UPR 50S SAT...RANGE FM THE LWR 40S TO LWR 50S
SUN...AND RANGE FM THE UPR 30S TO MID 40S MON.

&&

.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
TEMPORARY CLEARING OF SOME OF THE LOW CLOUDS HAS ALLOWED SOME OF THE
TAF SITES. LOW CLOUDS OR IFR FOG ARE EXPECTED TO FILL BACK IN LATE
THIS EVENING AS THE AIR NEAR THE SURFACE CONTINUES VERY MOIST AND AN
INVERSION REMAINS IN PLACE. LIFR VSBYS ARE NOT OUT OF THE QUESTION.

A FAST MOVING SHORT WAVE APPROACHES FROM THE SW OVERNIGHT. HI RES
MODELS AGREE WITH BRINGING PCPN BACK TO THE AREA BETWEEN 10 AND 13Z.
THIS OCCURS AHEAD OF A COLD FRONT AND WITH STRONG UPPER LEVEL
DYNAMICS. PCPN IS EXPECTED TO CHANGE TO SNOW AT RIC AND SBY...WITH
POSSIBLY SOME SLEET DURING THE CHANGEOVER. THE FORECAST CALLS FOR
AROUND 2 INCHES OF SNOW AT SBY WITH LESS THAN AN INCH AT RIC. AT
THIS TIME IT APPEARS THAT PCPN WILL END BEFORE THE COLDER AIR MAKES
IT TO THE REST OF THE TAF SITES. CIGS ARE EXPECTED TO REMAIN IFR
DURING THE PCPN AND MUCH OF THE TIME THE VSBY AS WELL.

OUTLOOK...TUESDAY NIGHT BEGINS A STRETCH OF DRY AND VFR WX WHICH
EXTENDS AT LEAST INTO FRIDAY. THERE WILL BE A CHC FOR PCPN OVER
THE WEEKEND.

&&

.MARINE...
LO PRES WILL MOVE ACRS THE CAROLINAS AND OFF THE CST TNGT INTO TUE.
SW OR W WINDS 10 KT OR LESS THIS EVENG...WILL BECOME RATHER STRONG
FM THE NNE THEN NW FOR TUE THRU TUE NGT. AT THIS TIME...HAVE ISSUED
A SCA FOR THE CSTL WTRS DURING THIS TIME PERIOD FOR A LITTLE
STRONGER WINDS (THAN CHES BAY/SND/RIVERS) AND SEAS BUILDING TO 5 TO
6 FT. FOR NOW...HAVE CAPPED WINDS IN THE CHES BAY AND CURRITUCK SND
AT 15 KTS...BUT MAY NEED TO ADD AT LEAST THE SRN CHES BAY ZNS
(632-634) AND SND (633) BEFORE ALL IS SAID AND DONE. CALMER
CONDITIONS WED AFTN INTO WED NGT...BEFORE STRONG NW WINDS RETURN
AGAIN ON THU.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY FROM 9 AM TO 4 PM EST TUESDAY FOR
     MDZ021>025.
NC...NONE.
VA...WINTER WEATHER ADVISORY FROM 9 AM TO 4 PM EST TUESDAY FOR
     VAZ072>077.
     WINTER WEATHER ADVISORY FROM 6 AM TO 4 PM EST TUESDAY FOR
     VAZ048-049-062>064.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM TUESDAY TO 4 AM EST WEDNESDAY
     FOR ANZ650-652-654.
     SMALL CRAFT ADVISORY FROM 10 AM TUESDAY TO 4 AM EST WEDNESDAY
     FOR ANZ656-658.

&&

$$
SYNOPSIS...AJZ
NEAR TERM...AJZ
SHORT TERM...AJZ/LKB
LONG TERM...TMG
AVIATION...LSA
MARINE...TMG