Area Forecast Discussion
Issued by NWS Wakefield, VA-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KAKQ 251035
Area Forecast Discussion
National Weather Service Wakefield VA
635 AM EDT THU AUG 25 2016
High pressure is expected to dominate the overall weather pattern
through the upcoming weekend into early next week. Warmer and more
humid conditions return Thursday into the weekend.
.NEAR TERM /THROUGH TONIGHT/...
Latest GOES water vapor imagery depicts anomalous upper level high
over the Deep South. Energy associated with yesterday`s convection
over the Midwest is also visible dropping over West Virginia. That
energy is expected to drop into the region this morning, resulting
in mid-high level cloudiness. Otherwise, near seasonable lows
observed across the region.
Surface ridge pushes south of the region today, resulting in return
flow. The upper level high builds northeast over the TN valley, as
850mb temps warm to 18-19C (+1 standard deviation). Highs warm into
the upper 80`s to low 90`s. Pressure falls ahead of an approaching
cold front will result in a lee/thermal trough. Warm temperatures
aloft and limited moisture will keep the forecast dry, but do
anticipate a partly cloudy to perhaps mostly cloudy sky as
additional energy drops into the region in the northwest flow aloft.
Shortwave energy pushes offshore this evening as the upper high
continues to build into the region. Clouds will also push offshore
with a mostly clear to partly cloudy sky forecast tonight. Lows
generally in the upper 60`s to low 70`s, or roughly 10 degrees
warmer than this morning.
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
The anomalous upper high centers over the Mid-Atlantic states
Friday, as a weak cold front attempts to drop into the forecast
area. 850mb temperatures warm to 18-20C (approaching +2 standard
deviations) across the region, resulting in a hot day. Highs
forecast solidly in the mid 90`s inland (cooler along the coast).
The front drops into the region late Friday as the surface trough
weakens. Based on the position of the upper level high and anomalous
temperatures aloft, expect only afternoon cu, even with a warm and
relatively unstable air mass. Moisture also limited with
precipitable waters at or below 1.5 inches. Have lowered POPs to
silent. Mixed layer dewpoints progged in the upper 60`s to low 70`s,
so do not anticipate dewpoints to mix lower than the upper 60`s. The
result will be heat indices in the upper 90`s to around 100. The
weak front stalls over the northern local area Friday night. Lows
forecast in the low to mid 70`s.
Surface high pressure builds over the Canadian maritimes Saturday as
the upper high remains centered over the Mid-Atlantic. While heights
rise slightly over the region, 850mb temps and low level thicknesses
decrease slightly as flow becomes onshore. Still warm though, with
highs generally in the low 90`s (cooler near the coast). Afternoon
cu expected across the south, but the forecast remains dry.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Benign and mainly dry conditions are expected to prevail Sunday
through Wednesday as a mid/upper level anticyclone becomes anchored
over the Southeast and Mid-Atlantic, which will keep the primary
upper jet energy displaced well to the north of the local area. Very
isolated sea-breeze convection is possible Sunday/Monday aftn, but
dry conditions and a lack of upper support will limit coverage.
25/00z. 25/00z GFS/ECMWF suggest that the upper ridge begins to
dampen by Tuesday/Wednesday allowing for wnw flow across the nrn Mid-
Atlantic, and the potential for tropical energy to push into the ne
Gulf and Southeast. There is still no strong support for pcpn but
given the weakening of the ridge a minimal (20%) chc of
showers/tstms is forecast for Tuesday/Wednesday. Highs Sunday
through Wednesday should range from the mid 80s at the coast to the
upper 80s/low 90s inland. Lows through the period average in the
upper 60s to mid 70s.
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A ridge of high pressure has located over the southeast local area this
morning. The result is a light southerly flow at the TAF sites.
The exception is KECG, which is located in the axis and has calm
winds. The calm winds and moist low levels have produced some
patchy ground fog. That fog will burn off quickly by 12Z.
Otherwise, mid-high clouds associated with an upstream,
dissipating convective complex will spill into the area this
morning. Expect scattered to broken clouds with decks 4-6k feet
AGL through the afternoon as another disturbance drops into the
region. Southerly winds all sites increase to 5 to 10 knots
today. High pressure slides farther offshore tonight with
lingering mid level clouds over the region. Winds light and
OUTLOOK...A cold front approaches the area Friday. This front is
expected to weaken and move to the north during the weekend.
Otherwise dry weather is expected through Monday.
High pressure will slide farther offshore today into
tonight. A southerly wind will average 10-15kt today, and
potentially reach a solid 15kt across the Bay and nrn ocean zones
tonight. A very weak cold front approaches from the nw Friday and
crosses the area late Friday night into Saturday. The wind will
remain southerly ahead of the front Friday, but diminish to 5-10kt.
High pressure then settles off the New England coast Sunday into
early next week resulting in a potential period of prolonged onshore
flow, although the wind should be aob 15kt. Seas average 2-3ft
through Saturday with 1-2ft waves in the Bay. Tropical cyclone
Gaston is expected to track to a position east of Bermuda by early
next week. This should result in long period swell propagating
toward the coast, with seas building to 3-4ft, and possibly 5ft out