Area Forecast Discussion
Issued by NWS Wakefield, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS61 KAKQ 180817
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
417 AM EDT SAT APR 18 2015

.SYNOPSIS...
WEAK HIGH PRESSURE BUILDS ACROSS THE AREA TODAY. A COLD FRONT
DROPS SOUTH ACROSS THE AREA TONIGHT...THEN STALLS OVER CENTRAL
NORTH CAROLINA ON SUNDAY. THE STALLED FRONT LIFTS BACK NORTHEAST
AS A WARM FRONT SUNDAY NIGHT...BEFORE A ANOTHER COLD FRONT
CROSSES THE AREA LATE MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
SCATTERED SHOWER ACTIVITY ACROSS THE EASTERN PIEDMONT AND THE
LOWER MD EASTERN SHORE HAS WANED EARLY THIS MORNING.
HOWEVER...PLENTY OF CLOUD COVER STILL LINGERS AND AM ALSO NOTICING
PATCHY DENSE FOG DEVELOPING...ESPECIALLY IN AREAS THAT RECEIVED
RAIN EITHER LAST EVENING OR EARLIER THIS MORNING. THE FOG IS DENSE
AND WIDESPREAD ENOUGH TO WARRANT A DENSE FOG ADVISORY ON THE LOWER
MD EASTERN SHORE THRU 8 AM. THE WEAK UPPER FEATURE RESPONSIBLE FOR
THE SHWER ACTIVITY EARLIER SHIFTS OFFSHORE AROUND 12Z AND SHOULD
SEE A NICE DAY TODAY (AFTER ANY LOW CLOUDS/FOG DISSIPATE).

WNW FLOW ALOFT RESULTS IN MOSTLY SUNNY CONDITIONS ACROSS THE NORTH
TODAY...PARTLY SUNNY SOUTH. HIGH RES MODELS INSIST ON A FEW
SHOWERS AND MAYBE AN ISOLD TSTM DEVELOPING ALONG THE VA/NC BORDER
INTO NE NC THIS AFTN. HAVE ADDED SOME LOW POPS (>30%) TO ACCOUNT
FOR THIS. HIGH TEMPS MID-UPR 70S ALONG THE COAST (EXCEPT NEAR 70
RIGHT AT THE BEACHES) TO THE UPR 70S-LOW 80S INLAND.

STRONGER SFC HIGH PRESSURE BUILDS SOUTH INTO THE REGION LATE
TONIGHT IN THE WAKE OF A WEAK BACKDOOR COLD FRONT. MAINLY CLEAR
TO PARTLY CLOUDY AND COOLER OVERNIGHT WITH LOW TEMPS IN THE UPR
40S N TO THE LOW/MID 50S SOUTH.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
HIGH PRESSURE SHIFTS OFF THE COAST SUN MORN WITH LOW LEVEL FLOW
BECOMING ESE. MEANWHILE...LOW PRESSURE WILL BE TRACKING TOWARD THE
LOWER GREAT LAKES STATES...PUSHING A WARM FRONT NE TOWARD THE
MID-ATLANTIC REGION. STARTING OUT SUNNY-PARTLY CLOUDY...THEN
INCREASING CLOUDS EXPECTED MIDDAY THROUGH THE AFTN (FROM W-E).
LATEST MODELS COMING IN A LITTLE FASTER WRT TIMING OF ARRIVAL OF
ANY RAIN. HAVE CHANCE POPS AS FAR EAST AS A LINE FROM LKU-RIC-NTU
BY 16-18Z SUN...INCREASING TO LIKELY/CATEGORICAL POPS ALL AREAS
BY 00Z. HIGH TEMPS IN THE MID/UPR 60S...WITH SOME LOW 70S POSSIBLE
SOUTH.

SIGNIFICANT INFLOW OF DEEP LAYERED MOISTURE INTO THE REGION SUN
NIGHT AS WARM FRONT MAKES PROGRESS NE THROUGH THE FA. MAY BE PERIODS
OF MODERATE/HEAVY RAIN...AND WOULD NOT RULE OUT ISOLD (ELEVATED)
THUNDER. THE AREA OF RAIN EXPECTED TO SHIFT OFF THE CST MONDAY
MORNING...WITH TROUGH ALOFT APPROACHING FROM THE WEST BY LATE MON
AFTN (LIKELY LEADING TO SCT SHWRS/TSTMS). LOOKS LIKE A MARGINAL
SEVERE WX THREAT FOR MON AFTN ATTM. OTW...VRB CLOUDS-PARTLY SUNNY
MIDDAY/AFTN ON MON. HIGH TEMPS LOW/MID 70S EAST...UPR 70S- NR 80
WEST.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
COLD FRONT EXITS THE MID-ATLANTIC COAST TO BEGIN THE EXTENDED PERIOD
MONDAY NIGHT AS THE CUT-OFF LOW LIFTS INTO THE GREAT LAKES REGION.
WILL MAINTAIN CHANCE POPS (SOLID CHANCE ALONG THE COAST) MON
NIGHT...BUT LATEST MODELS HAVE SPED UP FRONTAL PASSAGE.
THEREAFTER...BLOCKY FLOW PROGGED TO PREVAIL THRU THE END OF THE
PERIOD AS THE UPPER LOW REMAINS OVER THE GREAT LAKES/NEW ENGLAND.
SFC HIGH PRESSURE BUILDS ACROSS THE SE STATES/SRN MID-ATLANTIC
REGION TUES. WLY/DOWNSLOPE FLOW AND A MOSTLY SUNNY-PARTLY CLOUDY SKY
WILL RESULT IN SLIGHT ABOVE NORMAL TEMPS...GENERALLY IN THE LOW 70S
INLAND AND MID-UPPER 60S COASTAL AREAS. HIGH PRESSURE PUSHES OFF THE
COAST WEDS AS A SHORTWAVE DIVES DOWN THE BACKSIDE OF THE UPPER LOW
OVER THE GREAT LAKES REGION. ASSOCIATED COLD FRONT FORECAST TO DROP
OVER THE OH VALLEY WEDS. TEMPS WEDS NEAR NORMAL...GENERALLY IN THE
MID-UPPER 60S. COLD FRONT CROSSES THE LOCAL AREA LATE WEDS NIGHT-
THURS MORNING...BUT PARALLEL FLOW ALOFT WILL STALL THE FRONT OVER
THE MID-ATLANTIC REGION. 17/12Z GFS STALLS THE FRONT OVER THE LOCAL
AREA WITH MORE MOISTURE THAN ITS 17/12Z ECMWF COUNTERPART...WHICH
PUSHES THE FRONT THRU WITH LITTLE FANFARE. HAVE OPTED FOR SLIGHT
CHANCE POPS THURS-THURS NIGHT ATTM DUE TO UNCERTAINTY. NEAR NORMAL
AGAIN THURS...BEFORE COOLING SLIGHTLY INTO THE LOW-MID 60S INLAND TO
MID-UPPER 50S COASTAL AREAS.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
A WEAK SURFACE TROUGH WILL PASS ACROSS THE REGION OVERNIGHT.
EXPECT SCT-BKN CLOUD COVER ~10KFT UNDERNEATH CIRRUS. A FEW SHRA
WILL ACCOMPANY THE TROUGH (WITH ONE PRESENTLY MOVING E OF
SBY)...BUT SHOULD REMAIN AWAY FROM THE TERMINALS AFTER 06Z. SOME
IFR FOG IS POSSIBLE PRIMARILY AT RIC/SBY/PHF. THE FOG IS NOT
EXPECTED TO BE DENSE WITH MID/HIGH CLOUD COVER OVERHEAD...WITH
THE LOWEST VSBY AVERAGING 1-2SM. ANY FOG SHOULD DISSIPATE AFTER
13-14Z WITH MAINLY SCT CLOUDS THROUGH THE REMAINDER OF THE DAY. A
LIGHT SSW WIND OVERNIGHT WILL SHIFT TO NNE BEHIND THE SURFACE
TROUGH GENERALLY AFTER 10Z.

DRY CONDITIONS PREVAIL UNTIL LATER SUNDAY AFTERNOON INTO SUNDAY
NIGHT AS A COMPLEX LOW PRESSURE SYSTEM IMPACTS THE REGION. RA AND
DEGRADED FLIGHT CONDITIONS ARE EXPECTED SUNDAY NIGHT. ANOTHER
IMPULSE TRACKS ACROSS THE REGION MONDAY AFTERNOON/EVENING
BRINGING A CHC OF SHRA AND TSRA. HIGH PRESSURE BUILDS ACROSS THE
SOUTHEAST STATES TUESDAY AND WEDNESDAY AS LOW PRESSURE LINGERS
OVER THE GREAT LAKES. THIS SHOULD ALLOW DRY CONDITIONS TO RETURN.

&&

.MARINE...
WEAK HIGH PRESSURE BUILDS OVER THE MID ATLANTIC TODAY IN THE WAKE OF
A SURFACE TROUGH. THE WIND WILL SHIFT FROM SSW ~5KT TO NNE EARLY
THIS MORNING WITH THE PASSAGE OF THE TROUGH. BY THIS AFTERNOON...THE
WIND WILL REMAIN LIGHT AND BECOME SEA/BAY BREEZE DOMINATED WITH HIGH
PRESSURE OVER THE AREA. A BACKDOOR COLD FRONT DROPS N-S ALONG THE
COAST LATE TONIGHT. THIS WILL PRODUCE A WIND SHIFT TO NE. SPEEDS ARE
EXPECTED TO AVERAGE 10-15KT LATE TONIGHT INTO SUNDAY
MORNING...ALTHOUGH SOME HIGH-RES NUMERICAL GUIDANCE SUGGEST 20KT IS
POSSIBLE IN THE IMMEDIATE WAKE OF THE BOUNDARY. LOW PRESSURE LIFTS
INTO THE ERN GREAT LAKES SUNDAY AFTERNOON/EVENING...WITH SECONDARY
LOW PRESSURE DEVELOPING OVER THE MID ATLANTIC SUNDAY NIGHT. THIS
WILL TIGHTEN THE PRESSURE GRADIENT AND ALLOW WIND SPEEDS TO INCREASE
TO 20-25KT BAY/25-30KT OCEAN OUT OF THE SE. THE FLOW BECOMES
SOUTHERLY MONDAY WITH SPEEDS DIMINISHING TO 10-15KT. SEAS BUILD TO 4-
5FT LATER SUNDAY AFTERNOON IN RESPONSE TO ONSHORE FLOW...WITH SEAS
BUILDING TO 5-7FT (MAINLY N) SUNDAY NIGHT...BEFORE SUBSIDING TO 3-5FT
MONDAY. AN SCA HAS NOT BEEN ISSUED YET AS THIS IS PRIMARILY A LATE
3RD/4TH PERIOD EVENT. A COLD FRONT APPROACHES FROM THE W MONDAY
AFTERNOON/EVENING...AND MOVES ACROSS THE COAST LATE MONDAY NIGHT.
HIGH PRESSURE BUILDS ACROSS THE SOUTHEAST TUESDAY AND WEDNESDAY AS
LOW PRESSURE LINGERS OVER THE GREAT LAKES. AT THIS TIME...SUB-SCA
CONDITIONS ARE EXPECTED POST-FRONTAL TUESDAY.

&&

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

&&

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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.