Area Forecast Discussion
Issued by NWS Wakefield, VA

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FXUS61 KAKQ 251932
AFDAKQ

Area Forecast Discussion
National Weather Service Wakefield VA
332 PM EDT SUN SEP 25 2016

.SYNOPSIS...
High pressure over New England will extend south across the Mid
Atlantic region tonight and Monday. A strong cold front will cross
the region Tuesday. An upper level low will track across the area
later in the week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Cool air wedge in place across the area as high pressure drifts east
across New England. Latest models not as bullish with the wdsprd
moisture as drier air continues to filter south along the coast.
TSCTNS indicating the moist E-SE flow off the ocean will keep BKN-
OVC conditions across the piedmont with SCT clouds east to the Ches
Bay/Tidewater/nrn Outer Banks to CLR skies along the eastern shore.
Expect a dry evening. Some weak lift noted across the swrn most
zones (FVX-AVC) for some spotty light rain/drizzle to develop
after 06Z. Lows 55-60, 50-55 across the lwr Md eastern shore given
a mstly clear sky. Some patchy fog possible in areas that do clear.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
The high moves off the New England coast Monday with the next front
approaching from the west late. Upper ridge flattens which should
slow the advance of the front and serve to break down the cool air
wedge during the afternoon. TSCTNS show the BKN clouds hold firm
west of I95 through much of the day with SCT-BKN clouds to the
east. Pcpn wise, light rain/drizzle across the swrn zones early,
a several hour break in pcpn chcs through 18z, then slght chc
shwrs once again mainly west of I95 ahead of the approaching
front. Highs in the mid to upr 70s.

Models continue to show a strong cold front crossing the area late
Monday night and Tuesday. Weak s/w energy progged along the boundary
as it crosses sern zones Tuesday afternoon. Good feed of moisture
along and ahead of it with PW`s climbing to around 1.75 inches.
Instability is marginal, but kept low chcs for thunder with the
actual fropa. Kept likely pops with the time frame for the most
wdsprd pcpn coming late Mon nite and Tue morning. Models show drier
air filtering across NWRN zones Tues afternoon to end pcpn. Kept
high chc pops across the SE. Lows Mon nite in the 60s. Highs Tues in
the 70s. QPF btwn 1/2 to 1 inch.

Forecast for the mid week period becomes problematic and will all
depend on the track and available moisture associated with a deep
anomalous upper level low progged to drop south from the great lakes
region. The cold front clears the coast Tues night so expect pcpn
to wind down across the fa with chc pops lingering along the coast
through the nite. Lows range from the mid-upr 50s across northern
zones to the mi-upr 60s sern zones. Chc pops Wed for now with the
highest pops across the SE. Highs in the 70s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Medium range guidance continues to indicate anomalous heights over
Canada through the period, as well as over the western Atlantic. A
deep/anomalous upper low drops over the eastern Great Lakes region
Wednesday, under the upper ridge. Ensemble and deterministic
guidance continues to struggle with a more progressive versus
blocked flow over the eastern CONUS. The result is a relatively low
confidence forecast, but have trended more toward GFS/GEFS
solutions.

Tuesdays cold front progged to stall along the coast in deep layer
southwesterly flow across the Mid-Atlantic. POPs taper off inland
Tuesday night, with chance POPs remaining across the southeast
forecast area. A series of upper level disturbances will lift along
the frontal boundary Wednesday. The combination of waves lifting
along the front and strong upward vertical motion will bring solid
chance POPs back to the southeast local area and slight chance to
low end chance inland. The upper low locates in the vicinity of the
Mid Atlantic region Thursday. While the best moisture pushes
offshore, will keep mention of slight chance to chance POPs Thursday
and Thursday night to account for uncertainty and potential light
rain. Thereafter, the upper low likely begins to slowly lift
northeastward as the upper ridge over the western Atlantic begins to
break down. With the upper low lifting away from the region Friday
and Saturday, large scale subsidence over the region will result in
a drying trend. Will keep chance POPs northeast Friday and retain
silent POPs on Saturday.

Slightly below normal temperatures forecast through the period, with
highs generally in the low to mid 70`s. Lows range from the low to
mid 50`s inland to mid 60`s along the coast.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
Drier air from the north continues to filter south along the coast
this afternoon. This is resulting in VFR conditions with only SCT
SC along the Delmarva, SCT-BKN SC between 4-5K ft ivof the Ches
Bay, BKN-OVC SC between 3-5K ft across the piedmont. Nearest MVFR
cigs are across the mts. Models now showing only SCT clouds along
the coast tonight with differing solutions for RIC. Given the lgt
onshore flow and position of the high, decided to keep a BKN SC
deck around 4K ft at RIC through the night with SCT SC elsewhere.
Fog not expected to be a big issue tonight but can`t rule out some
ptchy MVFR VSBYS toward sunrise in areas where it does CLR. Any
pcpn is expected to be confined to the mts.

OUTLOOK...The next chance for widespread precipitation arrives
Monday night into Tuesday ahead of a strong cold front. Showers
will linger through the mid week period as an upper level low
tracks across the region.

&&

.MARINE...
Cold front has located south of the waters early this morning, as
high pressure builds in from the north. North to northeast winds of
10 to 15 knots observed over the waters, with occasional gusts of 20
knots over the southern coastal waters. Have dropped SCA headlines
for the lower Chesapeake Bay. Seas remain elevated thanks to distant
tropical cyclone Karl and onshore flow, ranging from 3 to 5 feet.
SCA headlines remain in effect for the coastal waters. Based on the
latest guidance, have extended headlines through 1 pm this
afternoon. Thereafter, seas subside to 3 to 4 feet. This mornings
cold front lifts back to the north Monday as a cold front approaches
from the northwest. Flow becomes south to southeast with marginal
SCA conditions possible late Monday into Monday night. The front
pushes across the region Tuesday, likely stalling along the coast
Tuesday night and Wednesday. A weak pressure gradient progged over
the region, but a cooler and drier air mass may result in at least
marginal SCA conditions late Tuesday night. An upper level low is
progged to drop into the region Wednesday and Thursday, resulting in
unsettled weather conditions through the end of the week. Flow
generally out of the north.

&&

.HYDROLOGY...
The Cashie River at Windsor remains in minor flood stage. The
river is forecast to slowly fall below flood stage by late this
afternoon. See FLSAKQ for details.

&&

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

&&

$$
SYNOPSIS...MPR
NEAR TERM...MPR
SHORT TERM...MPR
LONG TERM...MAS
AVIATION...MPR
MARINE...MAS
HYDROLOGY...



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