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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 310513
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1213 AM EST SAT JAN 31 2015

.SYNOPSIS...
COLD HIGH PRESSURE BUILDS INTO THE REGION THROUGH TONIGHT. A LOW
PRESSURE SYSTEM WILL AFFECT THE AREA SUNDAY INTO MONDAY. HIGH
PRESSURE RETURNS TO AREA THROUGH MID WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ALLOWED WIND ADSY ON THE ERN SHORE TO EXPIRE...STILL GETTING
FREQUENT GUSTS TO 30-35 MPH...WITH A FEW OF THE TYPICALLY WINDIER
SPOTS ALONG THE BAY SEEING AN OCCASIONAL GUST AS HIGH AS 40 MPH...BUT
THESE VALUES FALL SHORT OF WIND ADSY CRITERIA BY > 5 MPH.

TROUGH ALOFT CONTINUES TO PUSH OFFSHORE THRU EARLY MORNING AS SFC
HIGH PRESSURE BUILDS EAST FROM THE WNW. OTW... EXPECTING GUSTS UP
TO 30-35 SOUTH ALONG THE COAST OVERNIGHT...WITH LESSER WINDS
INLAND. SKIES WILL BE CLEAR. COMBO OF WINDS AND TEMPS DROPPING
INTO THE TEENS/LOW 20S WILL RESULT IN WIND CHILLS DROPPING TO THE
SINGLE DIGITS AND TEENS.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
CANADIAN SFC HI PRES ARRIVES FM THE WNW ON SAT RESULTING IN
DRY/CHILLY CONDS. STARTING OUT MNLY SUNNY...W/ (MID/HI LVL) CLDNS
BEGINNING TO SPREAD INTO THE RGN FM THE W BY LT IN THE DAY. HI
TEMPS FM THE L30S OVR THE LWR MD ERN SHORE TO THE U30S TO L40S
ELSW. MEANWHILE...LO PRES NOW IN THE SW CONUS WILL BE MOVING INTO
THE SRN PLAINS. MOISTURE WILL BE INCRSG SIGNIFICANTLY IN ADVANCE
OF THAT SYS THROUGH THE PLAINS AND TWD THE LWR/MID MS VLY LT SAT.

MDLS OVR THE PAST COUPLE OF DAYS HAVE HAD DIFFICULTY W/ THE
HANDLING OF THE SW STORM SYS...AND A SYS IN THE NRN BRANCH OF THE
JET STREAM DIGGING INTO THE NCNTRL CONUS. A MORE SRN TRACK TO THAT
STM AS IT HEADED INTO THE ERN STATES WAS THE CASE WED/THU (THUS A
MUCH HIGHER PTNTL FOR COLDER/WINTRY P-TYPE)...BUT NOW THERE IS
MORE OF A TRANSFER/COMBO OF NRN/SRN STREAM SYSTEMS INVOF NATION`S
MIDSECTION SAT NGT INTO SUN MRNG. THIS RESULTS IN A MORE NRN TRACK
TO THE ENTIRE STM...W/ PRIMARY SFC LO PRES DEVELOPING INVOF MO
INSTEAD OF TO THE S CLOSER TO THE GULF CST. THE PATTERN INVOF
MDATLC IN NOT CONDUCIVE FOR A WIDESPREAD WINTER P-TYPE EVENT LT IN
THE WKND INTO MON W/ SFC HI PRES TO DRIFT TO OFF THE SE CONUS CST
(BY SUN AFTN)...COMBINED W/ LACK OF ANY NRN SFC HI PRES AND A MORE
NRN W-E TRACK TO THE SFC LO PRES.

THE AIR OVR THE FA (ESP NNW PORTION) ON SUN MAY BE DRY/COLD ENOUGH
FOR RA/IP MIXTURE AT ONSET OF PCPN. TREND OF MDLS PAST 24 HRS HAS
BEEN TO BRING PCPN A LITTLE SLOWER INTO THE FA FM THE W THROUGH
THE DAY SUN. XPCG MODERATION OF THE AIRMASS OVR THE FA AS S WNDS
DEVELOP. ALL MDLS (NAM/GFS/ECMWF) AGREE W/ THE MORE NRN TRACK
(W-E) THROUGH THE MDATLC STATES LT SUN INTO MON. THUS...RA WILL BE
THE PRIMARY FCST P-TYPE SUN NGT INTO MON MRNG. TEMPS TO BOTTOM OUT
EARLY SUN EVE (IN THE M/U30S N...L/M40S S)...THEN RISE A FEW DEGS
F THEREAFTER INTO MON MRNG.

BY MIDDAY/AFTN MON...DRYING TREND TO BEGINNING BUT SUSPECT A BIT
OF A DELAY IN LO LVL CAA (OR ENOUGH COLD AIR TO CATCH THE PCPN
BEFORE IT EXITS) TO CAUSE ANY SGFNT SN THREAT (ON MON). WILL HAVE
A MIX RA/SN SHWRS FOR MNLY NNE PORTIONS (AFT MON MRNG)...MNLY CHC
SHWRS ELSW. HI TEMPS FM THE L40S NNW TO THE L/M50S SE.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
OTHER THAN SOME SOME LINGERING SNOW SHWRS OVR CSTL WTRS ERLY MON
EVE...EXPECT CLRG SKIES AND COLD MON NITE AS 1030 MB HIGH APPRCHS
FA FROM THE OHIO VALLEY. LOWS IN THE MID TEENS NORTH TO L20S SOUTH
XCPT M20S SERN BEACH AREAS.

RIDGE AXIS MOVES OVRHD ERLY TUE THEN SHIFTS OFFSHORE. MSTLY SUNNY
AND COLD. HIGHS IN THE 30S. MSTLY CLR TUE NIGHT. LOWS IN THE 20S.

MODELS CONTINUE TO HAVE DIFFICULTY WITH MID WEEK SYSTM AND OFFER
UP DIFFERENT TIMING AND MOISTURE SCENARIOS...SO A LOW CONFIDENCE
FCST CONTINUES UNTIL SOME KIND OF CONSISTANCE IN SEEN. HOWEVER...
THE TREND IS SLOWER IN BRINGING MSTR NORTH INTO THE FA AS SRN
STREAM LOW DVLPS IN THE NRN GOM THEN TRACKS NE ALONG THE SE AND
PSBLY MID ATLNTC COAST BEFORE PULLING NE AND AWAY FROM THE AREA.
MODEL GUID SUGGESTS LEANING MORE TOWARD THE GFS SOLN. XPCT INCRG
CLDNS WED. WENT WITH LOW CHC POPS ACROSS NC CNTYS LATE IN THE DAY.
HIGHS 45-50. CHC (LIQUID) POPS WED NITE WITH MIXED SNOW/RAIN LATE
ACROSS NRN MOST CNTYS. LOWS ARND FREEZING NRN MOST CNTYS TO THE
M-U30S OVR THE SOUTH. RAIN CHCS CONT THU XCPT FOR SOME RAIN/SNOW MIX
ERLY ACROSS THE NORTH. HIGHS IN THE 40S TO NR 50 SE.

IF THE 12Z ECMWF VERIFYS...THE STRNG HIGH PRS KEEPS SRN STREAM LOW
SOUTH WITH LITTLE IF ANY IMPACT ON FA. THIS HAS BEEN THE CASE MOST
OF THIS WINTER GIVEN NO REAL BLOCKING PATTERN SEEN. ITS SOLN WOULD
BE COLDER AND DRIER.

ANTHR ARCTIC HIGH PRESSURE BUILDS INTO THE AREA FROM THE NW BEHIND
THIS SYSTM BY FRIDAY. DCRG CLDNS THU NITE. LOWS IN THE 20S. MSTLY
SUNNY FRI. HIGHS IN THE 30S.

&&

.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
GUSTY NW WINDS WILL CONTINUE THROUGH MOST OF THE 00Z TAF PERIOD.
DUE TO COLD AIR ADVECTION AND A TIGHTENING PRESSURE GRADIENT...A
SURGE IN WINDS WILL AFFECT AREAS NEAR THE COAST THROUGH EARLY
SATURDAY MORNING. GUST VALUES WILL OCCASIONALLY SPIKE OVERNIGHT AT
SBY AND ORF BUT SELECTED VALUES FAIRLY CLOSE TO LAVMOS THAT ARE
EXPECTED TO BE WITHIN 10 KNOTS OF THE OBSERVATIONS. THE SKY WILL
BE MAINLY CLEAR WITH AN 8K FOOT BROKEN DECK MOVING SE OF ECG FIRST
COUPLE OF HOURS. SCT HIGH CLOUDS START TO MOVE IN SATURDAY AFTN.
WINDS DIMINISH LATE SATURDAY.

OUTLOOK...CLOUDS INCREASE SUNDAY AS LOW PRESSURE APPROACHES FROM THE
WEST. THE LOW CROSSES THE MID ATLANTIC STATES TO THE NORTH OF OUR
AREA SUNDAY NIGHT. MAINLY A RAIN EVENT IS EXPECTED WITH SOME IFR
PSBL AT THE TAF SITES...ESPECIALLY AT RIC AND SBY. RAIN ENDS LATE
MONDAY. DRY WEATHER RETURNS MONDAY NIGHT THROUGH MOST OF WEDNESDAY.
ANOTHER CHC OF RAIN DEVELOPS LATE WEDNESDAY.

&&

.MARINE...
CRNT HEADLINES REMAIN IN PLACE WITH GALES MOST PLACES TONIGHT AND
INTO SAT MORNING ACROSS THE NRN CSTL WTRS. STRNGST CAA TO OVRSPRD
THE MARINE AREA NXT SVRL HRS. 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.

FREEZING SPRAY ADVSRY CONTS TONIGHT INTO SAT MORNIND ACROSS CSTL
WTRS NRTH OF PARRAMORE ISLAND GIVEN THE FCSTD TEMPS/WIND GUSTS AND
CURRENT WATER TEMPS. THIS IS WHERE SOME MODERATE ICING IS LIKELY.
KEPT LIGHT ICING MENTIONED FARTHER SOUTH & IN THE CHES BAY ATTM.

XPCT SCA`S TO REPLACE GALES SAT MORNING WITH WINDS QUICKLY FALLING
BLO SCA LVLS SAT EVENING AS HIGH PRESSURE BUILDS INTO THE AREA.

NEXT LOW CROSSES THE AREA MONDAY WITH ANOTHER CAA SURGE SEEN BEHIND
THIS SYSTEM MON AFTERNOON AND NIGHT. HAVE WINDS IN SCA RANGE WITH
GUSTS CAPPED AT 30 KTS ATTM.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST TODAY FOR ANZ633-635>638.
     GALE WARNING UNTIL 4 AM EST EARLY THIS MORNING FOR ANZ630>632-
     634-656-658.
     GALE WARNING UNTIL 7 AM EST THIS MORNING FOR ANZ652-654.
     FREEZING SPRAY ADVISORY UNTIL NOON EST TODAY FOR ANZ650-652.
     GALE WARNING UNTIL NOON EST TODAY FOR ANZ650.

&&

$$
SYNOPSIS...JDM
NEAR TERM...JDM/LKB
SHORT TERM...ALB
LONG TERM...MPR
AVIATION...LSA
MARINE...MPR