FXUS61 KAKQ 150745

National Weather Service Wakefield VA
345 AM EDT Wed Jul 15 2020

High pressure builds into the region today into Thursday, and
then slides off the coast Friday. A trough of low pressure will
push into the area this weekend.


As of 345 AM EDT Wednesday...

The current analysis shows an upper trough over Atlantic Canada
downstream of a ridge over the Ern Great Lakes. At the surface,
weak high pressure is centered over wrn PA. Mostly clear early
this morning across the local area, with temperatures in the mid
60s to low 70s for much of the area, and mid 70s for the coasts
of SE VA and NE NC. Surface high pressure will build across New
England today, with a subtle boundary sliding across the region
this morning. Light onshore flow will develop behind this
boundary as the high builds to the NE. 850mb temperatures range
from 15-17C today supporting seasonal highs in the upper 80s to
low 90s, with mid 80s at the immediate coast with onshore flow.
Good mixing and drier air associated with the high to the NE
will allow aftn dewpoints to drop into the mid 60s away from the
coasts. Most areas will be partly to mostly sunny and dry
today, with only a slight chc of showers/tstms along the sea-
breeze over the MD Ern Shore, and an additional slight chc over
the SW Piedmont.


As of 345 AM EDT Wednesday...

High pressure remains centered over New England tonight into
Thursday. Therefore, expect mostly clear and dry conditions for
tonight, with lows in the upper 60s to low 70s. The low-level
flow becomes more SE by Thursday as the high nudges offshore.
Upper heights build across the region Thursday as a ridge builds
in aloft from the W. Thus, there is not much of a trigger for
aftn/early evening showers/tstms, so PoPs are largely 20% or
less, with the exception of the NW Piedmont where PoPs are up to
30% Thursday aftn as some showers/tstms could drift off the
mountains as some shortwave energy slides across the nrn
periphery of the ridge. 850mb temperatures Thursday remain in
the 15-17C range supporting seasonable highs once again in the
upper 80s/low 90s (mid 80s at the coast with onshore flow).
Dewpoints Thursday aftn range from the mid to upper 60s, so heat
indices will again be near or slightly above the ambient
temperature. Overall, quite typical for mid July. Hot and more
humid Friday with highs in the upper 80s to mid 90s, and max
heat indices in the mid 90s to around 100F. PoPs of 30-40% for
showers/tstms, especially during the aftn/evening, as a weak
trough/shortwave energy pushes into the region. Lows will mainly
range from the upper 60s to mid 70s Friday morning.


As of 350 PM EDT Tuesday...

The extended portion of the forecast will bring a continuation of
typical mid Summer conditions. Broad E-W high pres aloft (from the
wrn Atlantic to the Rockies will remain in control while a weak sfc
trough lingers over interior portions of the mid-Atlantic region.
There will be a slight weakness (or trough) in the ridge INVOF mid-
Atlantic and that will allow for poss mainly daily diurnal
SHRAs/tstms (highest PoPs 30-50% inland each day). Lows at night in
the l-m70s. Highs each day from the u80s-m90s.


As of 155 AM EDT Wednesday...

Weak high pressure builds in from the north early this morning
and becomes centered over New England today into tonight
promoting light onshore flow across the region. Mostly clear
this morning with some patchy fog possible through 12z. PHF will
be an exception where shallow ground fog is expected to produce
variable vsby (LIFR to VFR) through about 10z. FEW-SCT CU this
aftn for most of the area, with a slight chc of a sea-breeze
shower or tstm at SBY. Mostly clear conditions are expected by

The chc for aftn/early evening showers/tstms is generally less
than 15% at the TAF sites Thursday, 20-30% Friday, 30-40%
Saturday, and 20-40% by Sunday. VFR conditions are expected to
prevail outside of showers/tstms.


As of 230 AM EDT Wednesday...

Sfc high pressure will reside over New England today. Light and
variable winds this morning will become ESE 10 kt or less by
late this morning into the afternoon. Generally light onshore
flow is expected to continue through tonight, before a slight
uptick in east winds for Thursday (10-15 kt) which become SSE at
similar speeds on Friday. SSW winds aob 15 kt expected this
coming weekend as a weakening frontal boundary washes out over
the region. Waves on the Ches Bay will remain 1-2 ft through the
period; seas 2-3 ft.




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