Area Forecast Discussion
Issued by NWS Wakefield, VA

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FXUS61 KAKQ 202026
AFDAKQ

Area Forecast Discussion
National Weather Service Wakefield VA
426 PM EDT Fri Apr 20 2018

.SYNOPSIS...
High pressure will build into and over the region through the
weekend. Low pressure tracks from the Gulf Coast states
northeast up along the East Coast Monday through Wednesday.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
As of 335 PM EDT Friday...

Rather benign, quiet wx pattern across the eastern third of the
CONUS. 1036+ mb cool high pressure continues to nudge east from
the Great Lakes/Ohio Valley. Aloft, a broad upper ridge was
noted building east of the Mississippi River Valley behind
ejecting New England/Atlantic Canada upper trough. Meanwhile to
the west, early aftn satellite showing deepening upper level low
spinning over the Four Corners region toward the southern High
Plains.

Clear and cold again tonight with lows ranging fm the mid 30s
to arnd 40. No frost/freeze headlines necessary, but could see
some patchy frost developing after 06z/2 AM EDT tonight in
traditional cool spots out in the piedmont and NNW of SBY. Will
go ahead and note this potential in the HWO once again.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/...
As of 335 PM EDT Friday...

Cool high pressure builds in from the NW early in the period,
before sliding offshore Sunday into Sunday night. This will
bring a mainly clear/sunny day on Saturday, with gradually
increasing clouds Sunday afternoon and night. N or NE winds 10
kt or less veer around to the SSE Sunday through Sunday night,
bringing gradually moderating temps.

Have gone on the high side of guidance given sunny/dry
conditions on Saturday, with expected highs in the upper 50s to
lower 60 at the coast, mid to upper 60s inland. Mainly clear and
not as cold Sat night, with lows mainly in the lower 40s.
Gradually increasing clouds but still partly to mostly sunny on
average with highs mainly ranging thru the 60s. Lows in the mid
40s to low 50s Monday morning.

By Monday morning, next weather system currently over the desert
southwest will have pushed east toward the Gulf coast region.
Models are in general agreement that the trough will gradually
dampen, with the closed low opening up as the upper trough
traverses the southern tier of states over the weekend, with a
weak inverted trough developing over the southeast into Monday
morning. Given the antecedent dry conditions and the slow
evolution of this system, have kept Monday dry across the local
area, despite increase in cloudiness. May be a few light rain
showers possible across the I-85 corridor, but will hold pops at
slight chc or less. More clouds than sun will keep temps a few
degrees cooler into the low to mid 60s across the SW tier.
Otherwise, partly sunny across the northern tier. Rain chances
steadily increase Monday night across the Piedmont, with precip
spreading NNE into the area into Tuesday morning. Lows mainly in
the upper 40s in the piedmont to low 50s across Se coastal
plain.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 410 PM EDT Friday...

Rain will move into the area from SSW to NNE during the day on
Tuesday as the upper wave and associated sfc low pres push E/NE.
20/12z GFS/ECMWF/CMC are in good agreement that the area of light to
moderate rain will cover the entire CWA by late afternoon on Tuesday
and last through around 12z Wed. Given the agreement between the
most recent suite of guidance, have increased PoPs to 60-70% for the
entire CWA Tue-early Wed. Due to the rain, high temperatures will be
be in the low 60s for the bulk of the CWA on Tuesday. After the sfc
low tracks through eastern portions of the CWA Wed AM, the main area
of rain will exit the region. A few showers will still be possible
during the day, but temperatures should warm to near 70 on Wednesday
if the rain exits early enough (this looks more likely in southern
parts of the CWA).

12z GFS/CMC track another sfc low/weak cold front through the area
Thursday-Friday AM, but ECMWF does not have a rainy solution. Thus,
have kept PoPs at or below 40%. Highs around 70/lows between 50-55
expected Thu-Fri. An upper trough amplifies over the eastern US
Friday PM into next weekend as sfc low pressure is forecast to
deepen over the northeastern US at the same time. This will set the
stage for another chance of rain late Friday as well as below
average temperatures next weekend.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
As of 140 PM EDT Friday...

VFR conditions through the 18Z TAF period. N/NW winds are still
gusting up to 15-20 kt in the TAF sites, but will diminish
after 22z to less than 5 kt by 02z tonight. Otherwise, expect
SKC through the entire TAF period for all sites.

Outlook: VFR conditions will continue through Sun, with high
pressure over the region. A disturbance approaches the region
late Monday and Tuesday bringing the next chance for sub-VFR
conditions.

&&

.MARINE...
As of 410 PM EDT Friday...

No headlines in the short term tonight thru Sun. High pressure
builds in fm the NW tonight. A northerly surge is expected
later tonight, but this surge will be sub-SCA. High pressure
will then build over the region Sat and Sun resulting in benign
marine conditions. The high pushes off the Srn New England
coast early next week, as low pressure moves fm the Gulf coast
states to off the SE coast Mon into Wed. This will result in
increasing onshore flow. An E wind is expected to reach 10-15 kt
on Mon, then 15-25 kt late Mon night/Tue/Tue night. Onshore
flow will result in seas building to 6-10 ft by Tue night, with
4-5 ft waves in the Mouth of the Bay. Broad low pressure
crosses the region Wed, with the wind becoming WNW in the wake
of the low.

&&

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

&&

$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...MAS/MAM
LONG TERM...ERI
AVIATION...ERI
MARINE...TMG



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