Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 190328
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1028 PM EST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE BUILDS INTO THE AREA FROM THE NORTHWEST THROUGH
FRIDAY. LOW PRESSURE WILL TRACK FROM THE GULF OF MEXICO EASTWARD
AND OFF THE SOUTHEAST COAST LATE FRIDAY NIGHT INTO SATURDAY NIGHT.
HIGH PRESSURE WILL BE OVER THE AREA AGAIN DURING SUNDAY. ANOTHER
LOW PRESSURE AREA WILL MOVE NORTHEAST OUT OF THE GULF OF MEXICO
AND UP ALONG THE COAST LATE SUNDAY NIGHT INTO MONDAY NIGHT.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
LATEST REGIONAL RADAR MOSAIC DEPICTS LIGHT ECHOES OVER THE NRN
LOCAL AREA AND NRN VA THIS EVENING. HOWEVER...LATEST KWAL SOUNDING
DEPICTS A NARROW BAND OF MOISTURE FROM 12-16K FT AGL. THE DRY AIR
BELOW THAT LEVEL WILL PREVENT ANY PRECIP FROM REACHING THE GROUND.
THIS IN RESPONSE TO A SHEARING...LOW AMPLITUDE WAVE CROSSING THE
REGION. BASED ON BUFR SOUNDINGS AND LATEST IR SATELLITE
TRENDS...EXPECT CLOUD COVER TO STICK AROUND THRU LATE TONIGHT.
WAVE PUSHES OFFSHORE LATE TONIGHT INTO FRI MORNING...WITH SKIES
CLEARING THRU THE MORNING. SFC HIGH PRESSURE WILL CONTINUE TO
EXTEND INTO THE REGION...RESULTING IN CALM-LIGHT NLY WINDS. BUMPED
TEMPS DOWN A DEG OR TWO...EVEN WITH CLOUD COVER...IN THE UPPER 20S
TO LOW 30S.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
MODELS (GFS/NAM/ECMWF) CONTINUE TO TREND FARTHER S WITH PCPN AND
WEAK LO LATE FRI NGT INTO SAT NGT...DUE TO NRN STREAM UPR TROF
SWINGING EWRD FM THE UPR MIDWEST THRU THE GRT LKS. NAM IS THE
FARTHEST S AND THUS THE DRIEST MODEL. HI PRES STRETCHING FM
SCNTRL/SE CANADA SSE INTO THE MID ATLC WILL MAINTAIN DRY WX FRI
INTO FRI NGT. PARTLY TO MOSTLY SUNNY ON FRI WITH HIGHS RANGING FM
THE MID 40S TO ARND 50. MOSTLY CLEAR OR PARTLY CLOUDY FRI
NGT...WITH INCREASING CLOUDINESS SPREADING IN FM THE SSW. COLD
AGAIN WITH LOWS RANGING FM THE MID 20S TO LWR 30S.

FOR SAT INTO SAT NGT...WILL GO WITH A BLEND OF THE GFS/ECMWF WITH
LO PRES TRACKING FM THE GULF OF MEXICO EWRD AND OFF THE SE CST.
WILL GO WITH NO HIGHER THAN 30-40% POPS FOR EXTRM SRN VA AND NE NC
MAINLY SAT AFTN INTO EARLY SAT NGT. JUST HAVE SLGT CHC (20%) OR NO
PCPN (14%) ACRS NRN HALF OF CWA AT THIS TIME. ANY PCPN AT THE
ONSET OVR WRN/NW PIEDMONT COUNTIES COULD BE VERY LIGHT SLEET OR
SNOW. OTHERWISE...PCPN WILL BE JUST A COLD LIGHT RAIN...AND MAINLY
OVR EXTRM SRN VA AND NE NC. COULD BE A FEW FLURRIES MIXED IN AT
THE END EARLY SAT NGT. HI TEMPS ON SAT ONLY IN THE LWR TO MID 40S.
THE WEAK LO WILL BE WELL OFF THE SE CST LATE SAT NGT...WITH A MOSTLY
CLOUDY OR PARTLY CLOUDY SKY. LOWS SAT NGT RANGING FM THE UPR 20S
TO MID 30S. HI PRES WILL BE OVR THE AREA AGAIN DURING SUN. PARTLY
OR MOSTLY SUNNY WITH HIGHS IN THE MID TO UPR 40S.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
LOW PRESSURE IS EXPECTED TO DEVELOP OFF OFF THE SOUTHEAST COAST AND
TRACK NE OFF THE MID ATLANTIC COAST MONDAY INTO MONDAY NIGHT. TIMING
DIFFERENCES CONTINUE AMONGST 18/12Z NUMERICAL GUIDANCE...AND GIVEN
THIS POPS WILL REMAIN CAPPED IN THE CHC CATEGORY. POPS INCREASE TO
20-30% SUNDAY NIGHT...WITH 40-50% POPS ACROSS THE AREA MONDAY AND
MONDAY NIGHT. PCPN TYPE SHOULD GENERALLY BE RAIN...ALTHOUGH THERE
COULD BE A BRIEF PERIOD OF SLEET AT THE ONSET OVER THE NW PIEDMONT
LATE SUNDAY NIGHT AND EARLY MONDAY MORNING. HIGHS MONDAY SHOULD
RANGE FROM THE LOW 40S NW...TO MID 50S SE...AFTER MORNING LOWS IN
THE LOW 30S NW...TO AROUND 40 SE. MID-LEVEL RIDGING BRIEFLY BUILDS
INTO THE REGION TUESDAY (BRINGING MILDER CONDITIONS WITH HIGHS IN
THE LOW 50S NW TO NEAR 60 SE)...BEFORE LOW PRESSURE AND A STRONG
COLD FRONT IMPACT THE REGION TUESDAY NIGHT INTO WEDNESDAY. SPATIAL
AND TIMING DIFFERENCES CONTINUE WITH THE 18/12Z GFS TRACKING THE
SURFACE LOW W OF THE MOUNTAINS...AND THE 18/12Z ECMWF TRACKING THE
SURFACE LOW UP THE COASTAL PLAIN. THIS WILL HAVE IMPACT ON
TEMPERATURES AND WHETHER THE RAIN IS MORE STRATIFORM OR SHOWERY. IF
THE FARTHER W 18/12Z GFS WERE TO VERIFY THERE COULD BE A POTENTIAL
FOR THUNDER. HOWEVER...EVEN WITH THIS SOLUTION...SURFACE DEWPOINTS
AOA 60F REMAIN OFFSHORE. DRY AND BREEZY CONDITIONS WILL LIKELY
PREVAIL BY CHRISTMAS DAY.

&&

.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
SCT-BKN MID LEVEL CLOUDS WILL MOVE ACROSS THE TAF SITES DURING THE
OVERNIGHT HOURS INTO EARLY FRIDAY MORNING. THESE CLOUDS DISSIPATE BY
LATE MORNING. VFR CONDS WILL PREVAIL THROUGH THE 00Z TAF PERIOD.
WINDS WILL BE LIGHT GENERALLY FROM A NORTHERLY DIRECTION.

OUTLOOK...VFR CONDS AND LIGHT WINDS PREVAIL FRIDAY NIGHT. A LOW
PRESSURE SYSTEM TRACKING WELL TO OUR SOUTH SAT/SAT NIGHT MAY BRING
A PERIOD OF BKN/OVC CONDITIONS BUT CIGS ARE EXPECTED TO REMAIN 4-5
K FT OR HIGHER. HIGH PRESSURE BUILDS TO THE NORTH OF THE AREA
SUNDAY. A SERIES OF LOW PRESSURE SYSTEMS AND COMPLEX FRONTAL
BOUNDARIES WILL BRING CHANCES FOR RAIN AND PERIODS OF LOW CEILINGS
AND VISIBILITIES BEGINNING MONDAY.

&&

.MARINE...
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTHWEST TONIGHT INTO
FRIDAY. A SECONDARY NNW SURGE ARRIVES LATE TONIGHT INTO EARLY
FRIDAY. WIND SPEEDS OVER THE BAY COULD BRIEFLY REACH 20KT...BUT AT
THIS TIME THE DURATION IS NOT EXPECTED TO BE LONG ENOUGH TO WARRANT
AN SCA. HIGH PRESSURE BUILDS N OF THE REGION FRIDAY NIGHT THROUGH
SUNDAY...WITH WEAK LOW PRESSURE TRACKING OFF THE SOUTHEAST COAST
SATURDAY. THIS SHOULD RESULT IN N-NE FLOW AOB 15KT THROUGH
SUNDAY...WITH 2-3FT SEAS. ANOTHER LOW PRESSURE SYSTEM DEVELOPS OFF
THE SOUTHEAST COAST SUNDAY NIGHT...AND TRACKS NE OFF THE MID
ATLANTIC COAST MONDAY AND MONDAY NIGHT. THERE IS LITTLE TO NO CAA IN
THE WAKE OF THIS LOW...SO CONDITIONS SHOULD REMAIN SUB-SCA WITH A
WIND BECOMING WESTERLY BY TUESDAY. A POTENTIALLY STRONGER LOW TRACKS
W OF THE MOUNTAINS TUESDAY NIGHT...WITH A STRONG COLD FRONT CROSSING
THE MID ATLANTIC COAST WEDNESDAY.

&&

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

&&

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





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