Area Forecast Discussion
Issued by NWS Wakefield, VA

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430 FXUS61 KAKQ 121756 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1256 PM EST FRI FEB 12 2016 .SYNOPSIS... LOW PRESSURE DEVELOPS ALONG THE SOUTHEAST COAST THIS MORNING...LIFTING NORTHEAST OFF THE NORTH CAROLINA AND VIRGINIA COASTS LATER THIS AFTERNOON INTO TONIGHT. ARCTIC HIGH PRESSURE BUILDS IN FOR THE UPCOMING WEEKEND...RESULTING IN THE COLDEST TEMPERATURES SO FAR THIS YEAR. ANOTHER STORM SYSTEM WILL IMPACT THE REGION EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... LATEST SFC ANALYSIS DEPICTS DEVELOPING LOW PRESSURE ALONG A STATIONARY BOUNDARY JUST OFF THE SC COAST THIS MORNING. RADAR RETURNS DEPICTING CONVECTION AROUND THE NW PERIPHERY OF THE LOW. RADAR RETURNS OVER THE LOCAL AREA ARE ELEVATED AND NOT REACHING THE GROUND AS THE SUB CLOUD LAYER REMAINS QUITE DRY THANKS TO HIGH PRESSURE CENTERED OVER THE LOCAL AREA. HOWEVER...THE LATEST RETURNS ARE ALREADY INDICATING WHERE THE HEAVIEST SNOW BAND WILL LIKELY SET UP...ACROSS SE VA/NE NC. ALOFT...LATEST GOES WATER VAPOR IMAGERY AND RAOB PLOTS DEPICT SHORTWAVE ENERGY OVER THE MID MS VALLEY/TN VALLEY. THIS SHORTWAVE DIGS INTO THE SOUTHEAST STATES THRU THE MORNING HOURS...WITH HEIGHT FALLS FURTHER DEEPENING THE SFC LOW OFF THE SC COAST. THIS WILL LIKELY PUSH THE HEAVIEST SNOW BAND SWWD SLIGHTLY...WITH THE ADDED DYNAMICS DEEPENING THE MOISTURE FIELDS. THIS IS HANDLED WELL IN THE BUFR SOUNDINGS AND ISENTROPIC FIELDS. EXPECT SNOW TO BEGIN FALLING BY LATE MORNING TO AROUND NOON ACROSS NE NC/EXTREME SE VA...SPREADING NWD THRU EARLY AFTERNOON. STILL REMAINS QUITE A BIT OF MODEL/ENSEMBLE SPREAD WITH REGARDS TO QPF...WHICH WILL OF COURSE HAVE IMPACTS ON TOTAL SNOWFALL. TAKING A BLEND OF THE FAVORED SHORT TERM GUIDANCE STILL YIELDS A QPF FORECAST SIMILAR TO 24 HOURS AGO. THUS THE HEAVIEST AMOUNTS OF 10-15:1 SNOWFALL IS STILL FAVORED OVER NE NC AROUND THE ALBEMARLE SOUND. AMOUNTS OF 2-4 INCHES ARE STILL EXPECTED...WITH SOME BANDING EXPECTED AS NAM12 DEPICTS BEST FRONTOGENESIS ACROSS THAT REGION THIS AFTERNOON. WOULD NOT BE SURPRISED TO SEE SOME LOCALIZED 5 INCH AMOUNTS. AMOUNTS TAPER OFF TO 1 TO 3 INCHES INTO HAMPTON ROADS AND TOWARDS SOUTHAMPTON AND ISLE OF WIGHT COUNTIES. BASED ON AFOREMENTIONED QPF DISCREPANCIES...THERE STILL REMAINS A QUESTION OF HOW FAR NORTH LIGHT SNOW WILL SPREAD. HIGH PRESSURE SLIDES OFFSHORE AS THE LOW DEEPENS AND LIFTS ALONG THE COAST EARLY AFTERNOON. ASSOCIATED SUBSIDENCE WILL PUSH OFFSHORE AS BETTER FORCING ARRIVES OVER CENTRAL VA. MOISTURE IS NOT AS DEEP INTO CENTRAL VA...BUT THERMAL PROFILES/CROSS SECTIONS STILL INDICATE HIGH RH/ICE IN THE SNOW GROWTH ZONE WITH PLENTY OF OMEGA. BASED ON THE STRENGTH OF THE UPPER LEVELS...STILL THINKING THIS WILL BE ENOUGH FOR LIGHT SNOW INTO THE TRI-CITIES AND RICHMOND AREA. HOWEVER...SNOWFALL AMOUNTS WILL TAPER OFF TO LESS THAN HALF AN INCH TOWARDS RICHMOND DUE TO SHORT DURATION. COLD SURFACE/ROADWAYS WILL ALLOW ANY SNOW THAT FALLS TO ACCUMULATE ON THE ROADWAYS...SO DRIVING WILL STILL BE IMPACTED. FARTHER NORTHWEST OF RICHMOND COULD SEE JUST A DUSTING. TEMPS WILL STRUGGLE TO WARM INTO THE MID 30S TODAY THANKS TO ABUNDANT CLOUD COVER AND PRECIP. SNOW COMES TO AN END THIS EVENG/EARLY TNGT...AS THE SFC LO PUSHES WELL ENE OF THE MID-ATLC CST AND THE ARCTIC BOUNDARY PUSHES THRU THE REGION. CLEARING SW TO NE LATE TONIGHT WITH LOWS FALLING INTO THE TEENS TO LOW 20S. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... CLOSED UPPER LOW/ENERGY ASSOCIATED WITH THE POLAR VORTEX DIGS OVER NEW ENGLAND SATURDAY. ~1040MB ARCTIC HIGH PRESSURE BUILDS OVER THE MIDWEST...USHERING IN THE COLDEST AIR MASS OF THE SEASON FOR THE UPCOMING WEEKEND. WINDY SAT WITH NW WINDS GENERALLY 15 TO 25 MPH WITH GUSTS OF 30 TO 40 MPH (STRONGER NEAR THE COAST AND OVER THE EASTERN SHORE). HIGHS SAT FORECAST TO WARM ONLY INTO THE MID 20S NW TO LOW 30S SE (-2 STD DEV) UNDER A SUNNY TO MOSTLY SUNNY SKY. WIND CHILL VALUES WILL BE IN THE TEENS...RESULTING IN A RAW/COLD/WINDY DAY. TEMPS PLUMMET INTO THE SINGLE DIGITS TO LOW TEENS SAT NIGHT. WINDS DECOUPLE INLAND AS THE HIGH BUILDS INTO THE REGION...BUT WIND CHILLS STILL FORECAST IN THE SINGLE DIGITS INLAND TO 0 TO 8 BELOW NRN NECK TO THE ERN SHORE. THE HIGH CENTERS OVER THE LOCAL AREA SUNDAY WITH NLY WINDS 5 TO 10 MPH. SLIGHTLY COLDER SUN WITH DECREASED MIXING. HIGHS GENERALLY IN THE MID/UPPER 20S (-2 STD DEV) UNDER A SUNNY TO MOSTLY SUNNY SKY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE SHIFTS TOWARD NEW ENGLAND SUNDAY NIGHT WITH ATTENTION TURNING TO A DEVELOPING SYSTEM OVER THE DEEP SOUTH MONDAY. THERE REMAINS PLENTY OF UNCERTAINTY WITH RESPECT TO THE DETAILS...ALTHOUGH THE 11/12Z NUMERICAL GUIDANCE IS TRENDING SLOWER...AND WARMER FOR MONDAY NIGHT AND ESPECIALLY TUESDAY. THE 11/12Z GFS CONTINUES TO SHOW SOME LIGHT PCPN MONDAY AS A NRN STREAM TROUGH SWINGS ACROSS THE AREA. THIS WOULD MAINLY FALL AS SN OR SN/IP...WITH A TRANSITION TO RA CLOSER TO THE COAST BY AFTERNOON. SUBSTANTIAL WARMING ALOFT WOULD GENERALLY RESULT IN A TRANSITION TO RA MONDAY NIGHT...ASIDE FROM THE FAR NW WHERE MIXED PCPN COULD PERSIST INTO TUESDAY MORNING WITH AN IN-SITU WEDGE IN PLACE. THE LATEST DATA SCOURS OUT THE WEDGE BY AFTERNOON WITH P-TYPE BECOMING RA EVEN IN THE FAR NW. DRYING OCCURS MIDWEEK IN THE WAKE OF THE DEPARTING SYSTEM...WITH A NRN STREAM WAVE CLIPPING THE AREA LATE IN THE PERIOD. THIS WILL BRING ANOTHER SHOT OF COOLER AIR AS CANADIAN HIGH PRESSURE BUILDS INTO THE AREA THURSDAY/THURSDAY NIGHT. HIGHS MONDAY WILL LIKELY STRUGGLE TO GET OUT OF THE LOW 30S ALONG AND W OF I-95...WHILE COASTAL LOCATIONS WARM INTO THE UPPER 30S TO LOW 40S. TEMPERATURES REMAIN STEADY MONDAY EVENING AND BEGIN TO RISE OVERNIGHT EVENTUALLY WARMING INTO THE 40S TO LOW 50S TUESDAY. HIGHS WEDNESDAY ARE FORECAST TO REACH THE MID 40S TO LOW 50S...FOLLOWED BY LOW 40S NE...TO UPPER 40S SW THURSDAY. MORNING LOWS ARE FORECAST TO BE IN THE UPPER 20S TO MID 30S WEDNESDAY MORNING. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
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WK SFC LO PRES WILL BE EXITING NC/SC CST THIS AFTN/EVE. BROAD AREA OF SN TO MOVE ACRS MNLY SE VA/NE NC. PD OF MDT SN PSBL FM ABT 20-23Z/12...ESP AT ECG. ELSW...DRY LO LVL ATMOS XPD TO PREVENT ANYTHING MORE THAN FLURRIES RIC-SBY. TROUGH ALOFT TO PUSH ACRS THE RGN TNGT...PTNTL FOR SCT -SN...MNLY INVOF SBY FM ABT 02-03Z TO 08-09Z/13. OTRW...STRONG CDFNT TO PUSH ACRS THE RGN OVRNGT. GUSTY NW WNDS TO 25-35 KT TO DEVELOP LT TNGT/EARLY SAT MRNG...CONTG THROUGH THE DAY SAT. VFR AND DRY WX WILL PREVAIL SAT THROUGH SUN NGT. PCPN DEVELOPS MONDAY AS THE NEXT WX SYS APPROACHES FROM THE W. PCPN BEGINS AS SNOW MON MRNG...MNLY INLAND...BEFORE WARMER AIR WORKS IN AND CHANGES ANY SN TO RA FROM SE TO NW DURING MON. RA CONTS INTO TUESDAY AS LO PRES TRACKS ACRS THE AREA. DRY WX RETURNS WED.
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&& .MARINE... NO HEADLINES TODAY AS THE MARINE AREA WINDS WILL GNRLY BE AOB 15KTS AHEAD OF AN AREA OF LOW PRS PROGGED TO MOVE OFF THE CAROLINA COAST TONIGHT. ALTHOUGH THIS LOW WILL NOT BRING ANY WIND RELATED MARINE HEADLINES...THE ASSCTD PCPN WILL BRING REDUCED VSBYS IN SNOW/SLEET OF VARYING INTENSITIES LATE THIS AFTRN AND EVE. AS THE LOW LIFTS TO THE NE FRIDAY NIGHT A STRONG ARCTIC COLD FRONT WILL PASS ACROSS THE REGION WITH STRONG CAA DEVELOPING LATE FRIDAY NIGHT AND CONTINUING THROUGH SATURDAY INTO SATURDAY NIGHT AS ARCTIC HIGH PRESSURE BUILDS IN FROM THE NW. A NW WIND WILL AVERAGE 25-30KT WITH FREQUENT GUSTS OF 35-40KT OVER THE OCEAN AND BAY. SEAS BUILD TO 5-8FT WITH 4-5 FT WAVES IN THE BAY. GALE FLAGS HAVE BEEN RAISED FOR LATE TONIGHT THRU SATURDAY NIGHT. FOR THE RIVERS AND SOUND...WIND SPEEDS HAVE BEEN CAPPED AT HIGH-END SCA AT THIS TIME. EXPANDED THE FREEZING SPRAY WINDOW TO INCLUDE SAT...SAT NITE AND SUN MORN GIVEN FCSTD WND SPEEDS / GUSTS COMBINED WITH AIR TMPS BELOW 30 DEGREES. LIMITED THE FREEZING SPRAY TO THE MORE OPEN CHES BAY AND CSTL WATER AREAS. PER COORD WITH PHL...HOISTED FREEZING SPRAY ADVSRY FOR THIS TIME FRAME AS WELL. THIS MEANS LIGHT TO MDT ACCUMULATION OF ICE CAN BE EXPECTED ON VESSELS. THE WIND WILL DIMINISH SUNDAY INTO SUNDAY NIGHT AS THE HIGH SETTLES ACROSS THE AREA. LOW PRESSURE APPROACHES FORM THE SW EARLY NEXT WEEK. && .TIDES/COASTAL FLOODING... STRONG NW FLOW ASSOCIATED WITH AN ARCTIC COLD FRONT COULD PRODUCE BLOW-OUT TIDES / LOW WATER ADVISORIES SATURDAY AFTERNOON AND NIGHT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NCZ012>014. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR NCZ015>017- 030>032-102. VA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ092- 093-095>098-100-523>525. MARINE...FREEZING SPRAY ADVISORY FROM 7 AM SATURDAY TO NOON EST SUNDAY FOR ANZ630>632-634-650-652-654-656. GALE WARNING FROM 4 AM SATURDAY TO 4 AM EST SUNDAY FOR ANZ630>632-634-650-652-654-656-658. FREEZING SPRAY ADVISORY FROM 7 PM SATURDAY TO NOON EST SUNDAY FOR ANZ658. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 4 AM EST SUNDAY FOR ANZ633-635>638. && $$ SYNOPSIS...TMG NEAR TERM...SAM SHORT TERM...SAM/TMG LONG TERM...AJZ AVIATION...ALB/MPR MARINE...MPR TIDES/COASTAL FLOODING...

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