Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
132 PM EDT Tuesday Sep 1 2015
low pressure pushes off the North Carolina coast this morning. A
trough of low pressure develops along the coast today through
Thursday. High pressure prevails inland through the end of the
Near term /until 6 PM this evening/...
early morning stratus has developed over much of the local area this
morning thanks to abundant low level moisture. Patchy fog observed
over the Piedmont...where there are a few breaks in the stratus. A
few light showers remains near the Albemarle Sound...so will maintain
slight chance probability of precipitation through the rest of the morning for NE NC.
For today...the stratus deck will erode/lift shortly after daybreak.
Shortwave ridging builds over the middle-Atlantic region as surface high
pressure remains over the region. Model soundings indicate a rather
dry profile with warm temperatures aloft. A lack of appreciable forcing
will also help suppress any convection today. The exception will be
across the southeast...where better moisture and modest low level
convergence along the coast will result in a slight chance for
afternoon showers and thunderstorms. Thicknesses recover today
compared to 24 hours ago...pushing temperatures into the upper 80s to low
Short term /6 PM this evening through Thursday/...
an upper level ridge amplifies over the central Continental U.S. Through the
short term period...with high pressure remaining over the Middle-
Atlantic States. Shortwave prognosticated to drop over the central
Appalachians Wednesday morning...locating over the local area Wednesday
afternoon. Showers/thunderstorms are expected to develop over the
higher terrain Wednesday afternoon...drifting eastward into the Piedmont.
Theta-E advection and a warm/moist air mass may be enough to allow
showers/thunderstorms to survive into the Piedmont...but downslope
flow...a dry/well mixed sub cloud layer and weak flow/shear expected
to squash convection as it pushes eastward. Will maintain chance probability of precipitation
over the Piedmont...tapering off to slight chance into central Virginia.
Thicknesses yield highs in the low 90s most locales...after lows in
the upper 60s to low 70s Wednesday morning.
Upper trough drops over the Canadian Maritimes Thursday with an
associated area of low pressure pushing off the eastern Canadian coast.
This will produce weak surface troughing into central/eastern Virginia Thursday
afternoon. A warm/moist and unstable air mass will remain over the
local area. Weak perturbations in northwesterly flow aloft will provide
subtle forcing for ascent. Have maintained slight chance to low end
chance probability of precipitation Thursday afternoon...with the best chances along the surface
trough and seabreeze boundaries. While heights drop off
slightly...850 mb temperatures and thicknesses remain similar to
Wednesday...translating to highs in the low 90s (4 to 7 degrees above
normal). Mild again Thursday morning with lows in the upper 60s to low
Long term /Thursday night through Tuesday/...
extended period begins with a backdoor front moving across the area
on Friday...resulting in surface high pressure over the NE US
ridging south. The ridging will help to moderate temperature and
humidity through the weekend due to the NE to east flow. Weak middle level
troughing off the southeast will help generate showers and thunderstorms to
our south...but as the ridge at the surface and aloft builds over
the area...precipitation will be suppressed to the south of the akq
Forecast highs in the middle 80s inland and lower 80s near the coast
Sat through Monday. Low temperatures will range from the middle 60s to upper 60s
across the area.
Aviation /18z Tuesday through Sunday/...
last of MVFR ceilings eroding across coastal NE NC early this afternoon.
Otherwise...rest of day will have scattered-broken cumulus (mnly 4-6kft) which is
expected to dissipate early evening once heating wanes. Patchy fog possible after
mdngt tonight/early Wednesday morning. Have included IFR conds in sby...and
left out fog mention elsewhere due to uncertain timing and low
confidence. Isolated/scattered convection possible lt Wednesday/Wednesday night...otherwise mainly
dry/VFR conds west/ possible patchy fog for a few hours near sunrise through
end of the weak.
no flags expeceted despite weak low prs moving east from the Outer Banks
this morning. High prs builds in from the west resulting in light
onshore flow. Setup looking good for the afternoon seabreeze to develop.
Flow becomes S-SW tonight through Wednesday night (blo 15 kts) as the high
moves offfshore. Winds become north by Thursday as anthr area of high prs
builds in from the west. Winds expeceted to remain at or below 15 kts through Friday.
Seas around 2 feet. An extended prd of onshore flow may eventually build
seas out near 20 nm to 5 feet this weekend.
the National oceanic and atmospheric administration weather radio transmitter at Mamie is offline due to a
comms failure. Return to service is unknown at this time.