Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
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FXUS61 KAKQ 210622
Area Forecast Discussion
National Weather Service Wakefield VA
222 AM EDT THU JUL 21 2016
High pressure builds over the region through tonight then remains
in place through the weekend. This will result in dry and hot
conditions with heat building through the weekend.
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
Weak high pressure is moving over the Mid-Atlantic states tonight
as the upper trough off the New England coast exits and the large
ridge over the central US builds eastward. The radar still shows
some lingering convection from the heating of the day and the
interaction with sea breeze and outflow boundaries. These
lingering showers should continue to dissipate over the next
couple of hours. Have updated the forecast to show this
dissipation. Once the daytime cu is gone, do not see much forcing
to keep clouds going and the mos guidance agrees so have reduced
sky cover as most areas should see mainly clear sky overnight. For
now have kept the temperatures in the upper 60s to around 70
.SHORT TERM /8 AM THIS MORNING THROUGH SATURDAY NIGHT/...
Some low stratus is possible early Thursday morning along the
lower Bay with some patchy fog inland. Any fog or low clouds will
burn of quickly giving way to mostly sunny skies. Anomalous upper
ridge over the nation`s mid section continues to build eastward
Thursday and Friday. Thursday`s onshore flow suppresses the heat
for one more day. Similar thicknesses and low level temps to today
will result in highs back in the upper 80s to around 90. Dry with
a mostly sunny sky. Lows Thursday night in the upper 60s to low
70s under a mostly clear sky. The upper ridge expands eastward
Friday, reaching the Piedmont. Highs forecast in the mid 90`s
with heat indices around 100. Pressure falls along the lee side
of the mountains will sharpen a thermal trough over the Piedmont,
but a lack of moisture and appreciable forcing results in silent
POPs. However, will see more afternoon cumulus. Have added a
slight chance of showers and storms in the far west on Saturday as
a few storms could develop over the higher terrain and drift east.
Highs in the mid 90s with heat indices of 100-104. The heat will
build in more on Sunday as highs reach the upper 90s with heat
indices between 105 to 109. There could be an afternoon tstm with
the thermal trough remaining overhead.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A thermal trough is expected to remain in place Mon-Wed for
continued very warm to hot conditions. 595dm upper ridge also
remains situated off the SE coast. A slight buckle in the ridge
across the Northeast/Mid- Atlantic due to a weak upper trough
passage will knock a few degrees off max temps but still remain
above normal. Highs in the mid/upr 90s Monday and low to mid 90s
Tue/Wed. Thunderstorm chances will mainly be tied to the aftn/eve
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
High pressure will settle over the Mid Atlantic States today and
slide off the coast from late this afternoon/evening and remain
there Fri into the weekend.
As of 06Z...Light winds prevail, patchy fog is developing but has
not really affected TAF sites yet. Will forecast some patchy fog
for KSBY/KPHF/KECG, but think only KSBY has a decent chance for
vsbys dropping to IFR (<3SM), during the 08-12Z timeframe.
OUTLOOK...Mainly VFR conditions and dry weather can be expected
through Saturday. An isolated shower/tstm just inland from the
coast can`t be ruled out this afternoon. Widely scattered
afternoon thunderstorms are possible Sunday and Monday with a
better chance on Tuesday.
Headlines are not anticipated over the next several days, though
conditions may come close to reaching SCA thresholds Fri night. High
pressure over the area today will slide offshore and become
centered off the mid- Atlantic/SE coast Thu- Fri as a weak front
approaches from the NW Fri night into Sat. This front looks to
remain N of the CWA, with a pre-frontal trough in place over the
region on Sat. Winds today will be light from the E-NE (<10kt) and
transition to the S to avg around 10 KT tonight into Fri morning.
Bay waves avg 1-2 ft with coastal seas 2-3 ft. The pressure
gradient will increase a bit by late Fri, especially by fri night
so S/SW winds will ramp up and avg around 15 KT during this
period. A few gusts may reach SCA thresholds across the Bay (20
KT) and northern coastal waters (25 KT) Fri night as warm water
temperatures will be conducive to mixing the low level nocturnal
Jet. Still would be marginal at best, with waves over the Bay
building to 2-3 ft, and coastal seas to around 4 ft N and 3 ft S.
The sfc trough/boundary drops into the area on Sat with lighter
W/SW flow turning back to the S Sat night. The front then washes
out/dissipates on Sun.