-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 031821
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
121 PM EST TUE MAR 3 2015

.SYNOPSIS...
HIGH PRESSURE WILL SLIDE OFFSHORE THIS AFTERNOON. A WARM FRONT
LIFTS NORTHEAST ACROSS THE REGION TONIGHT...FOLLOWED BY A COLD
FRONT SLOWLY CROSSING THE AREA WEDNESDAY AFTERNOON THROUGH
WEDNESDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
LATE THIS MORNG...HI PRES WAS CNTRD RIGHT ALONG THE CST. FLOW
ALOFT IS GENERALLY FM THE W...WELL OUT AHEAD OF BROAD TROF OVER
THE WRN CONUS. TEMPS WERE SLOWLY CLIMBING THRU THE 30S TO NEAR 40
DEGREES OVR THE AKQ CWA...WITH DWPTS RANGING FM THE MID TEENS TO
THE UPR 20S. RDR SHOWED ONLY VRY LGT MIXED PCPN OR RAIN OVR THE
MTNS OF WEST VA AND SW VA. CNTR OF HI PRES WILL PUSH OFFSHR THIS
AFTN...BUT LOW LEVEL CAD REMAINS OVER THE FA. A CLOUDY SKY WILL
LIMIT TEMP RISES THIS AFTN...WITH HIGHS ONLY RANGING FM THE MID
30S EXTRM NW TO THE MID 40S OVR NE NC. BETTER COVERAGE OF PCPN IS
EXPECTED MID/LATE AFTN...WITH BEST PCPN CHCS (50-60%) FOR MAINLY
LGT RAIN ACRS NRN AND WRN AREAS. MODEL SOUNDINGS CONTINUE TO
SUPPORT A BRIEF PERIOD OF -FZRA OVR FAR NW AREAS BETWEEN 16-20Z
AS TEMPS STRUGGLE TO REACH/SURPASS 32F THRU EARLY THIS AFTN.
CONFIDENCE REMAINS LOW ATTM GIVEN MARGINAL TEMPS AND A WARM DAY
YESTERDAY. OTHERWISE...P-TYPE TO BE ALL RAIN OVR THE REGION THIS
AFTN/EVENG.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
WARM FRONT TO LIFT NE THROUGH THE FA TONIGHT. BEST MOISTURE AND
UVM ACRS CNTRL/NRN PORTIONS OF FA...THUS THE HIGHEST POPS...W/
WITH CHC POPS LIMITED TO SRN VA/NE NC. BULK OF THE RA LIFTS TO NRN
PORTION BY LT AT NGT. LO TEMPS LIKELY ARND 00Z/04 WITH RISING
TEMPS THROUGH THE NIGHT. TEMPS BY 12Z/04 WED RISE INTO THE MID/UPR
40S TO MID 50S SE.

FA BECOMES "WARM SECTORED" WED DUE TO SURGE OF A STRONG SSW FLOW.
THERE RMN TIMING ISSUES W/ THE APPROACHING CDFNT FM THE NNW...HOWEVER
A GFS/ECMWF BLEND LOOKS LIKE A GOOD COMPROMISE. WILL HAVE HIGHEST POPS
(40-70%) BY AFTN ACRS NRN TIER OF FA...W/ SLGT CHC TO CHC (20-40%)
TO THE S. FOR NOW...LEAVING OUT ANY MENTION OF T ACRS SRN VA/NE
NC...SINCE IT APRS MOST OF MOISTURE CONFINED TO W/ AND BEHIND THE
FNT. HI TEMPS FM THE U50S/L60S N TO L70S IN FAR SE VA/NE NC.

JUST ONE YEAR AGO...MARCH 2ND-3RD...WENT FM 60S TO L70S (THE 2ND)
TO A FEW INCHES OF SN (ON THE 3RD). THIS MAY OCCUR AGN THIS WK
(WED-THU).

FCST CHALLENGES CONT WED NGT THROUGH THU AS CDFNT SETTLES SSE
THROUGH THE FA...AND ANOTHER AREA OF ARCTIC SFC HI PRES BUILDS TWD
THE MS/OH VLYS. WILL LEAN TWD THE FASTER ARRIVAL OF COLDER SFC
AIR FM THE NNW (GFS/ECMWF) BY LT WED NGT AND CONTG ON THU. THE
MDLS EACH HINT AT WK SFC LO PRES TRACKING THROUGH NC AS S/W ALOFT
(IN FAST SWLY FLO) IS SHEARED AS IT MOVES EWD INTO THE RGN. ALL
THIS LEADS TO A TRANSITION (WRT P-TYPE) LT WED/THU. RA...BECOMES
MIXED W/ IP-CHANGING TO SN/IP THEN ENDING AS SN FM NNW TO SE ACRS
THE FA (LASTLY ACRS NE NC BY MID OR LT AFTN THU). TIMING THOSE
TRANSITIONS AT THIS POINT VERY DIFFICULT...THOUGH CURRENTLY EXPECT
A LEAST LGT SN ACCUMS FOR AREAS N OF THE NC/VA BORDER BEFORE THE
DAY ENDS THU (T-2 INCHES S...1-4 INCHES N (HIGHEST PTNTTLY FM
RIC-SBY)). ALONG W/ THE TRANSITION TO WINTRY PCPN...GUSTY NNE WNDS
WILL BE PUSHING COLDER AIR INTO THE RGN. LO TEMPS WED NGT FM ARND
30F N TO THE LOW/MID 40S FAR S. TEMPS THU STEADY OR FALLING.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
COLD TO BEGIN THE EXTENDED IN WAKE OF THURS COLD FRONT...BUT
MODERATING TEMPS THRU THE WEEKEND WILL BRING TEMPS BACK TO NEAR
NORMAL EARLY NEXT WEEK.

SHORTWAVE PUSHES OFFSHORE THURS NIGHT WITH THE NRN PORTION OF THE
FRONT PUSHING WELL OFFSHORE. SRN PORTION PUSHES SWD OVER THE GULF
STATES/NRN GULF...STALLING IN WLY FLOW ALOFT. ENDED CHANCE POPS NEAR
THE COAST AT MIDNIGHT...WITH DRYING/CLEARING CONDITIONS THEREAFTER.
1030+MB ARCTIC HIGH PRESSURE BUILDS OVER THE REGION FRI...RESULTING
IN ANOTHER COLD DAY WITH HIGHS AROUND 20 DEGS BELOW NORMAL. H85
TEMPS BOTTOM OUT AROUND -12C (-2 STD DEV)...WITH THICKNESSES
YIELDING TEMPS IN THE LOW-MID 30S. SFC HIGH PUSHES OFFSHORE FRI
NIGHT WITH LIGHT RETURN FLOW HELPING MODERATE LOW LEVEL THICKNESSES.
TEMPS FORECAST IN THE MID-UPPER TEENS FRI NIGHT UNDER MOSTLY CLEAR
SKIES. THEREAFTER...MEDIUM RANGE GUIDANCE BEGINS TO DIVERGE THANKS
TO DEVELOPING SPLIT FLOW OVER THE WRN CONUS. THE UPPER PATTERN WILL
AGAIN BE CHARACTERIZED BY CYCLONIC FLOW (TROUGHING) OVER THE ERN
CONUS AND RIDGING (RETURN TO A +PNA) OVER THE WRN CONUS. MODELS
STRUGGLING WITH A NUMBER OF CANADIAN IMPULSES SET TO IMPACT THE NE
STATES...BUT ALSO SRN STREAM ENERGY OVER THE BAJA THIS WEEKEND.
ECMWF RATHER ROBUST WITH THIS ENERGY...TRANSLATING ACROSS NRN MEXICO
AND THE SRN PLAINS SAT NIGHT-SUN...POSSIBLY PHASING WITH NRN STREAM
ENERGY OVER THE MIDWEST. THIS SOLUTION WOULD LIFT THE STALLED
FRONTAL BOUNDARY OVER THE GULF NWD LATE IN THE WEEKEND...BRINGING
RAIN TO THE REGION EARLY NEXT WEEK. THE GFS SHEARS THE
ENERGY...KEEPING IT WELL SOUTH OF THE REGION...KEEPING THE LOCAL
AREA DRY. HAVE TRENDED FORECAST TOWARD A WPC/ENSEMBLE APPROACH WHICH
KEEPS THE SRN STREAM WAVE FLAT AND THE LOCAL AREA DRY THROUGH THE
WEEKEND..WITH MODERATING TEMPS. HIGHS SAT FORECAST IN THE UPPER
40S-LOW 50S INLAND AND LOW-MID 40S NEAR THE COAST. HIGHS SUN IN THE
MID 50S INLAND AND MID-UPPER 40S NEAR THE COAST.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AN OVERCAST DECK AROUND 3500-5000 FT AGL PERSISTS THIS AFTN AS
LIGHT NE WINDS START TO BECOME MORE ELY. A WARM FRONT LIFTS NORTH
THROUGH THE AREA TONIGHT. A PERIOD OF -SHRA ARE EXPECTED TO
DEVELOP AFTER 03/2100Z ACROSS MOST OF THE REGION...WITH MORE
STEADY RAINFALL ACROSS THE NRN NECK AND MD/VA EASTERN SHORE. IFR
CIGS OF 500-1000 FT AGL ARE EXPECTED TO DEVELOP AS PRECIP BEGINS
AND THEN PERSISTING THROUGH THE OVERNIGHT HOURS. THERE SHOULD BE
A BRIEF PERIOD OF IMPROVING CONDITIONS WITHIN THE WARM SECTOR WED
MORNING...ESPECIALLY OVER SE VA/NE NC WHERE THE CIGS MAY BREAK UP
NICELY. HOWEVER...A COLD FRONT IS EXPECTED TO DROP THROUGH THE
REGION WED AFTERNOON FOLLOWED BY DETERIORATING FLIGHT CONDITIONS.
THE CHANCE OF RAIN INCREASES LATER WEDNESDAY AFTERNOON...WITH RAIN
OVERSPREADING THE ENTIRE REGION WEDNESDAY EVENING. MODELS ARE
TRENDING WARMER SLIGHTLY LONGER WHICH SHOULD RESULT IN A
TRANSITION TO A WINTRY MIX WITH SLEET FROM NW TO SE AS THU
PROGRESSES AND EVENTUALLY TO ALL SNOW BY LATE THU AFTN/EARLY
EVENING. ADDITIONALLY...A GUSTY NORTHERLY WIND WILL DEVELOP ALONG
THE COAST THURSDAY. HIGH PRESSURE SETTLES OVER THE AREA FRIDAY AND
SATURDAY.

&&

.MARINE...
1030MB SURFACE HIGH PRESSURE SHIFTS OFFSHORE TODAY ALLOWING A
10-15KT NNE WIND TO BECOME SE AOB 10KT BY AFTERNOON. THE HIGH SHIFTS
FARTHER OFFSHORE TONIGHT AS A WARM FRONT LIFTS THROUGH THE REGION.
DESPITE A STRONG LLJ IT WILL BE DIFFICULT TO OBTAIN SCA CONDITIONS
GIVEN WAA OVER COLD WATER. GIVEN THIS...WIND/SEAS HAVE BEEN CAPPED
BELOW SCA CRITERIA. OVERALL...EXPECT A SSW WIND ~15KT FOR THE BAY
AND A 15-20KT FOR THE OCEAN ALONG WITH 3-4FT SEAS/2-3FT WAVES. A
COLD FRONT APPROACHES FROM THE NNW WEDNESDAY MORNING...AND SLOWLY
DROPS TO A POSITION NEAR THE VA/NC BORDER BY LATE AFTERNOON/EARLY
EVENING. THE FRONT THEN BECOMES NEARLY STATIONARY WEDNESDAY NIGHT AS
LOW PRESSURE TRACKS ALONG THE BOUNDARY. CAA COMMENCES THURSDAY AS
THE LOW PULLS OFFSHORE AND CONTINUES INTO THURSDAY NIGHT AS 1040MB
HIGH PRESSURE BUILDS IN FROM THE NW. SCA CONDITIONS ARE LIKELY
DURING THIS TIME PERIOD WITH A NORTHERLY WIND OF 20-25KT...AND 4-7FT
SEAS (HIGHEST S) AND 3-4FT WAVES IN THE BAY. HIGH PRESSURE RETURNS
FRIDAY AND FRIDAY NIGHT...AND SLIDES OFFSHORE SATURDAY.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...JDM
NEAR TERM...JDM/TMG
SHORT TERM...ALB/JDM
LONG TERM...SAM
AVIATION...AJZ
MARINE...AJZ/BMD