-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 301214
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
714 AM EST FRI JAN 30 2015

.SYNOPSIS...
A COLD FRONT WILL MOVE OFF THE COAST THIS MORNING...FOLLOWED BY
COLD HIGH PRESSURE LATE TONIGHT THROUGH SATURDAY NIGHT. A STRONG
LOW PRESSURE SYSTEM WILL AFFECT THE AREA SUNDAY INTO MONDAY. HIGH
PRESSURE RETURNS TO AREA THROUGH MID WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...DEFORMATION BAND DEVELOPED ON THE FRONT...WHICH IS
STARTING TO EXIT THE COAST AS OF 640 AM. MADE A QUICK ADJUSTMENT
TO ADD LIGHT RAIN SHOWERS ALONG THE COAST INTO FAR SE VA AND
INTERIOR NE NC AS WELL.

PREVIOUS DISCUSSION...SHORTWAVE ENERGY DROPPING OUT OF THE GREAT
LAKES BEGINS TO OVERTAKE AND MERGE WITH SHORTWAVE ENERGY MOVING
ACROSS THE CAROLINAS EARLY THIS MORNING...THUS BECOMING A STRONGER
AND MORE ORGANIZED UPPER LEVEL TROUGH. THIS OCCURS INVOF THE
FRONTAL BOUNDARY...WHICH IS CAUSING A DEFORMATION ZONE TO DEVELOP.
FARTHER NORTH ACROSS THE NRN NECK...MIDDLE PENINSULA... AND MD/VA
EASTERN SHORE...WEAK RADAR ECHOES IN CLEAR AIR MODE ARE BEGINNING
TO BLOSSOM AS A JET STREAK AND WEAK SHORTWAVE MOVE ACROSS THIS
AREA. ONCE AGAIN...CAN JUSTIFY NO HIGHER THAN 15-20% POP
ESPECIALLY SINCE SFC DEWPOINT DEPRESSIONS ARE TOO LARGE. GIVEN THE
BETTER JET SUPPORT WITHIN THIS AREA...THERE MAY BE JUST ENOUGH
WEAK LIFT THROUGH THE DENDRITIC GROWTH ZONE (DGZ) TO CARRY A
SLIGHT CHANCE OF SLEET MIXED WITH RAIN ACROSS THE MD EASTERN SHORE
THROUGH THIS MORNING.

OTHERWISE...COLD AND DRY MODIFIED ARCTIC AIR MOVES INTO THE REGION
BEHIND THE DEPARTING CLIPPER FRONT THUS CAUSING THE SFC PRESSURE
GRADIENT TO TIGHTEN SIGNIFICANTLY. THROW IN STRONG COLD AIR
ADVECTION AND A FAVORABLE MIXING ENVIRONMENT...AND YOU GET A
RECIPE FOR GUSTY NW WINDS RESULTING IN A BRISK DAY. WINDS WILL
BECOME GUSTY BY MID MORNING AND MAX OUT AROUND MID-LATE AFTN/EARLY
EVENING. THE STRONGEST WIND GUSTS ARE EXPECTED TO OCCUR ACROSS THE
MD/VA EASTERN SHORE WITH GUSTS UP TO 40-50MPH...WHILE INTERIOR
VA/NE NC SHOULD EXPERIENCE GUSTS UP TO 30-35MPH. A WIND ADVISORY
HAS BEEN ISSUED FOR THE MD/VA EASTERN SHORE FROM EARLY THIS
EVENING THROUGH MIDNIGHT TONIGHT. TEMPERATURES IN THE 40S TODAY
WILL YIELD WIND CHILL FACTORS MAINLY IN THE 30S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
CANADIAN HIGH PRESSURE SLOWLY BUILDS INTO THE MID ATLANTIC REGION
FROM THE WEST TONIGHT AND THEN SETTLES OVER THE REGION SAT. NW
WINDS REMAIN BREEZY ALONG THE COAST ON SAT WITH GUSTS OF 25-30 MPH.
WIND CHILLS SAT MORNING START OUT FROM 0-15 DEGREES ABOVE ZERO AND
WARM THROUGH THE DAY. MOSTLY CLEAR SKIES AND DRY/STABLE CONDITIONS
WILL KEEP TEMPERATURES ON THE COLD SIDE FRI NIGHT/SAT. LOWS FRI
NIGHT IN THE UPPER TEENS MOST AREAS AND IN THE LOW-MID 20S FAR SE.
HIGHS SAT IN THE LOWER 40S MOST AREAS...UPPER 30S ALONG THE COAST
FROM THE NRN NECK TO VIRGINIA BEACH...AND IN THE LOW-MID 30S MD/VA
EASTERN SHORE. HIGH PRESSURE SLIDES OFF THE SE COAST LATE SAT
NIGHT INTO SUN AS A CLOUD SHIELD FROM THE NEXT APPROACHING SYSTEM
STARTS TO OVERSPREAD THE AREA. THE CLOUDS WILL PREVENT LOWS FROM
REACH THEIR FULL POTENTIAL...THEREFORE EXPECT WARMER LOWS SAT
NIGHT IN THE 20S.

A SOUTHERN STREAM LOW PRESSURE IS ANTICIPATED TO TRACK INTO THE
AREA FROM THE SOUTHWEST LATE SUN AFTN/EARLY EVENING INTO MONDAY.
WHILE ISENTROPIC SFCS SHOW MOISTURE MOVING INTO THE REGION THROUGH
SUN MORNING...TIME HEIGHTS/CROSS SECTIONS REVEAL DRY LOW LEVELS
AND IT IS ASSUMED THAT THE MOISTURE PRESENT IS FROM
INCREASING/THICKENING CLOUDS. HAVE THEREFORE REMOVED PRECIP
CHANCES FROM THE FORECAST FOR SUN MORNING. THE BEST LIFT/OMEGA
MOVES INTO THE AREA FROM THE WEST CENTERED AROUND 21Z...SO DO NOT
ANTICIPATE PRECIPITATION TO BEGIN UNTIL LATE AFTN/EARLY EVENING IN
NW AREAS OF THE FA (FROM ROUGHLY SOUTH HILL TO RICHMOND TO
SALISBURY). THE INCOMING LOW CROSSES THE REGION SUN NIGHT AND
WIDESPREAD PRECIPITATION IS ANTICIPATED. THE TRACK OF THE LOW HAS
TRENDED NORTHWARD WHICH IS KEEPING TEMPERATURES WARMER DURING SUN
NIGHT. THEREFORE...BEST CHANCE FOR SNOW IS ACROSS FAR NWRN
COUNTIES FROM LOUISA TO SALISBURY. LIGHT SNOW ACCUMULATIONS ARE
POSSIBLE (2 INCHES OR LESS WITH THIS FORECAST PACKAGE). A
RAIN/SNOW MIX WILL BE POSSIBLE FROM ROUGHLY FARMVILLE TO THE
RICHMOND METRO AREA TO THE VA EASTERN SHORE...OTHERWISE THE REST
OF THE AREA SHOULD EXPERIENCE RAIN. OVERALL QPF AMOUNTS ARE LESS
THAN 0.50 INCHES SUN NIGHT. TEMPERATURES MAY BE A BIT TRICKY SUN
AS WARMING IS EXPECTED UNDER DRIER CONDITIONS SUN MORNING. HIGHS
AROUND 50 SOUTH TO UPPER 50S CNTRL VA TO LOWER 40S NRN NECK AND
MD/VA EASTERN SHORE. TEMPERATURES SUN NIGHT SHOULD REMAIN FAIRLY
STEADY OVERNIGHT (WITH SLIGHT VARIATIONS OF A DEGREE OR TWO) DUE
TO THE STEADY PRECIPITATION PRESENT. LOW SUN NIGHT LOW-MID 30S NW
TO UPPER 30S TO LOWER 40S SE.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
THE PCPN THEN ENDS FM W TO E ON MON WITH HI TEMPS ONLY IN THE LO
30S N TO LO 40S S UNDER STRONG CAA. THE GENERAL IDEA WITH THIS
STORM IS THAT THE CURRENT TRACK FAVORS MAINLY A RAIN EVENT FOR
MUCH OF THE FA WITH SOME WINTRY PCPN MIXED IN AT THE BEGINNING AND
END OF THE EVENT ESPECIALLY OVER N AND W AREAS. THIS IS STILL
SEVERAL DAYS OUT AND SLIGHT CHANGES IN THE TRACK WILL MAKE A
DIFFERENCE OVER WHERE THE RA/SN LINE DEVELOPS. ANY PCPN ASSCTD
WITH MON STORM IS OFFSHORE BY 00Z TUE. CLRG SKIES AND COLD MON
NITE AS 1030 MB HIGH APPRCHS FA. LOWS IN THE TEENS TO L20S SRN
MOST CNTYS.

RIDGE AXIS MOVES OVRHD ERLY TUE THEN SHIFTS OFFSHORE. MSTLY SUNNY
AND COLD. HIGHS L-M30S. CLDS INCRS TUE NIGHT AHEAD OF NXT SYSTM.
KEPT IT DRY FOR NOW AS ANY PCPN SHUD STAY S&W OF FA THRU 12Z WED.
LOWS MAY OCCUR IN THE EVE THEN STDY OR RISE AFTR MIDNIGHT AS A S
WIND DVLPS. LOWS IN THE 20S TO L30S SERN AREAS.

MODELS SOLNS DIFFER A BIT WITH THE MID WEEK SYSTM. GFS TAKES SFC LOW
NE INTO THE GT LAKES RGN WITH THE TRAILING CDFRNT PROGGED ACROSS THE
FA WED NITE. IT ALSO DVLPS A LOW ON SRN END OF BNDRY. THIS ALLOWS
SAID BNDRY TO STALL JUST OFFSHORE ALLOWING THE LOW TO TRACK NE ALONG
THE SERN US COAST BUT STAY JUST SOUTH OF AKQ FA. THIS SCENARIO
BRINGS MILDER AIR IN AHEAD OF THE BNDRY FOR MAINLY RAIN...BUT A MIX
WITH THEN CHANGE TO SNOW WED NITE AS CAA DVLPS BEHIND IT. ECMWF HAS
THE LOW GOING INTO THE GT LAKES BUT SHOWS A STRNGR AND WETTER SRN
STREAM LOW MOVG NE ALONG THE MID ATLNTC COAST BEFORE LIFTING NE AWAY
FROM RGN THURS. WENT WITH CHC (LIQUID) POPS WED. MAY START OFF AS A
BRIEF RAIN/SLEET MIX ACROSS PIEDMONT ERLY DEPENDING ON HOW FAST THE
PCPN MOVES IN. HIGHS IN THE 40S. WENT WITH CHC POPS FOR A RAIN TO
SNOW SCENARIO WED NIGHT FOR NOW. THIS A RATHER LOW CONFIDENCE CALL
AND WILL LIKELY ALL DEPEND ON HOW MUCH MOISTURE IS AVAILABLE WHEN
THE COLD AIR OVRSPRDS THE RGN. LOWS M20S-L30S.

COLD WITH SOME LINGERING RAIN/SNOW SHWRS ALONG THE COAST THU MORN.
OTW...CLRD AND COLD AS STRNG HIGH PRS BUILDS IN FROM THE WEST. HIGHS
M30S-L40S.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
WINDS NOW SHIFTING TO THE WNW AND WILL THEN TURN TO THE NW OVER
THE NEXT FEW HRS. SHOWERS WILL AFFECT MAINLY KORF/KECG THROUGH
13-14Z...OTHERWISE CONDS TURN DRY. STILL DO NOT EXPECT CIGS TO
DROP TO MORE THAN ABOUT 4000 FT AND VSBYS WILL ONLY DROP SLIGHTLY
SO RETAINED P6SM WORDING.

GUSTY NW WIND WILL DEVELOP AFTER 14Z...WITH GUSTS INCREASING TO
AROUND 30 KT FROM 18Z-23Z. AT ALL SITES OTHER THAN KSBY WINDS
SLOWLY DIMINISH LATER THIS EVENING BUT SHOULD STILL BE GUSTING TO
20-25 KT (30-35KT AT KSBY).

DRY/LESS WINDY SAT AS THE AREA OF HIGH PRESSURE SLIDES ACROSS THE
REGION. A MORE MOIST FRONTAL SYSTEM IMPACTS THE REGION SUNDAY AFTN INTO
MONDAY. THIS LOOKS TO BE MAINLY RAIN ALTHOUGH THERE IS A CHANCE
FOR PRECIP TO MIX WITH OR CHANGE TO SNOW AT KRIC/KSBY ON THE BACK
SIDE OF THE SYSTEM BEFORE THE PRECIP ENDS ON MON.
-- End Changed Discussion --

&&

.MARINE...
DECIDED TO CANCEL ALL RAMP-UP SCA HEADLINES NOW THAT GALES ARE
WITHIN 12 HRS OF OCCURRING...OTHERWISE ONLY MINIMAL CHANGES TO
OVERALL THINKING WITH THE UPCOMING EVENT. WINDS WILL SHIFT TO THE NW
LATER THIS MORNING AND INCREASE...BUT WIDESPREAD GALE FORCE
WINDS MAY HOLD OFF UNTIL LATE AFTN AS COLD AIR SURGE WILL LAG BY
SEVERAL HRS. THINK THE STRONGEST WINDS...WITH GUSTS TO 45 KT OVER
NRN COASTAL WATERS...35-40 KT IN THE BAY AND SRN COASTAL
WATERS...AND ~35 KT IN MOST OF THE RIVERS WILL OCCUR THIS EVENING.
THIS IS WHEN THE PRESSURE GRADIENT WILL BE THE TIGHTEST AND WHEN
MUCH COLDER AIR (850 MB TEMPS DROPPING BELOW -12C) REALLY SURGE OVER
THE RELATIVE WARMTH OF THE WATERS (+5 TO +8 C). SEAS & WAVES RESPOND
TO THESE GUSTY WINDS. SEAS AVG 7-11 FT WITH WAVES IN CHES BAY 4-6
FT.

GIVEN THE TEMPS/WIND GUSTS AND CURRENT WATER TEMPS...HAVE A FREEZING
SPRAY ADVSRY FOR THE CSTL WTRS NORTH OF PARRAMORE ISLAND.
HOWEVER...HAVE DELAYED THE HEADLINE UNTIL AFTER MIDNIGHT AS SFC
TEMPS OVER THE WATERS WILL GENLY BE ABOVE FREEZING UNTIL LATER IN
THE EVENING. THIS IS WHERE SOME MODERATE ICING IS
LIKELY. KEPT LIGHT ICING MENTIONED FARTHER SOUTH & IN THE CHES BAY
ATTM.

WINDS DIMINISH ON SAT...THOUGH GALES WILL PERSIST IN THE MORNING
OVER NRN COASTAL WATERS...WITH SCA`S OVER THE REMAINDER OF THE
MARINE AREA. WINDS QUICKLY DIMINISH BLO SCA LVLS BY SAT EVENING
AS HIGH PRES BUILDS INTO AND OVER THE AREA SAT NIGHT.

NEXT LOW CROSSES THE AREA MONDAY WITH ANOTHER CAA SURGE SEEN BEHIND
THIS SYSTEM MON AFTERNOON AND NIGHT. GENLY HAVE WINDS IN SCA RANGE
FOR NOW...THOUGH AS MORE DETAILS IN TIMING AND LOCATION WITH THIS
SYSTEM ARISE WILL FINE TUNE THE FORECAST AND COULD SEE A PERIOD OF
GALES.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
MD...WIND ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT
     FOR MDZ021>025.
NC...NONE.
VA...WIND ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT
     FOR VAZ099-100.
MARINE...GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR ANZ635-636-638.
     SMALL CRAFT ADVISORY UNTIL NOON EST SATURDAY FOR ANZ633-637.
     GALE WARNING UNTIL 4 AM EST SATURDAY FOR ANZ630>632-634-656-
     658.
     GALE WARNING UNTIL 7 AM EST SATURDAY FOR ANZ652-654.
     FREEZING SPRAY ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST
     SATURDAY FOR ANZ650-652.
     GALE WARNING UNTIL NOON EST SATURDAY FOR ANZ650.
-- End Changed Discussion --

&&

$$
SYNOPSIS...BMD
NEAR TERM...BMD
SHORT TERM...BMD
LONG TERM...MPR
AVIATION...LKB
MARINE...LKB