Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
409 am EDT Monday Sep 1 2014
high pressure builds over the southeastern states today and
Tuesday. A weak front drops into the area Tuesday night and
settles near the Virginia North Carolina border Wednesday.
Near term /until 6 PM this evening/...
isolated showers/thunderstorms will pass over northern portions of the local area
through 12z as a weak trough passes over the northern mid-Atlantic.
Otherwise...mid/upper level ridging will continue to strengthen over
the southeast today. The low-level flow steadily veers to the SW
allowing for a favorable situation for strong surface heating. 850mb
temperatures approach 20c by this afternoon supporting highs in the
middle 90s away from the coastlines...with upper 80s/low 90s along the
coasts. Dewpoints should generally average 65-70f during peak
heating and this should keep heat indices at or below 100. There will be no
substantial trigger for convection...although a lingering surface
trough will support a low (20-30%) pop for afternoon/early evening
showers/thunderstorms generally east of the I-95 corridor.
Short term /6 PM this evening through Wednesday/...
Tuesday should be the hottest day as 850mb temperatures average
around 20c. This combined with deep mixing and a SW wind of 10-15mph
should help boost highs into the middle/upper 90s inland with low 90s
along the coastlines. Afternoon dewpoints should fall into the
middle/upper 60s...and once again this should keep heat indices at or below
100. Current forecast highs average around +1.5-2.0 St dev above
seasonal means...and approach but fall short of records...which are
listed below for reference. Tuesday should generally be dry as a
subsidence inversion inhibits convection. The approach and passage
of a weak cold front Tuesday night could trigger a few
showers/tstms...but overall coverage should be very limited.
The front stalls near the Virginia/NC border Wednesday. A slight chance pop
will be maintained in vicinity of the boundary...but overall expect
partly to mostly sunny conditions. Highs Wednesday should drop back
into the upper 80s/low 90s. Lows Tuesday/Wednesday mornings should
average in the low/middle 70s.
Long term /Wednesday night through Sunday/...
long term period will feature above normal temperatures and occasional
chances for rain. For Wednesday ngt/Thu...aforementioned weak frontal boundary
washes out over/just S of the forecast area while surface hi pressure builds across the
middle Atlantic. Did include a slight chance for a rain showers/thunderstorm over southern
areas closest to the greatest moisture axis and forcing...but
nothing widespread expected. Temperatures Wednesday will rise into the upper 80s to
lower 90s under a mostly sunny sky and light onshore winds.
For the remainder of the week...broad upper-level ridge across the eastern
Continental U.S. Will keep warm temperatures over the area. Surface hi pressure remains
offshore late in the week as a cold front approaches from the west.
Models agree on timing the front into the middle Atlantic over the
weekend...so did introduce a chance (30%) for afternoon/eveng
shras/tstms. Hi temperatures Friday and Sat will be in the upper 80s to lower 90s
with low temperatures in the middle 60s to lower 70s.
Aviation /08z Monday through Friday/...
VFR conditions prevail early this morning across the local area.
Scattered-broken middle level clouds (decks 4-6k feet agl) generally along and
north of a line from Farmville to Richmond and Salisbury.
Elsewhere...generally broken high clouds at or above 25k feet above ground level. Isolated
showers/thunderstorms ongoing north of a Richmond to Salisbury
line...possibly impacting ksby through early morning. Confidence is not
high...so will adjust tafs as needed. Otherwise...mixing will
preclude fog tonight as south winds average 5-7 knots. Will need to monitor
locales close to the Albemarle Sound for some stratus...with kecg
forecast to drop to IFR ceilings by 8-9z.
For today...little change in the pattern as VFR conditions prevail.
Isolated to widely scattered showers/thunderstorms possible along a
surface trough over eastern Virginia. Southerly winds generally around 10 knots with a few
gusts up to 20 knots this afternoon.
High pressure remains anchored over the western Atlantic through midweek as
a weak surface trough remains over the region. A cold front approaches
from the west on Tuesday...crossing the region late Tuesday night into
Wednesday. High pressure returns Thursday as the front stalls over the
Carolinas. Showers/thunderstorms possible each day.
surface high pressure remains anchored over the western Atlantic as a weak
surface trough locates west of the waters. Resultant gradient southerly flow
over warm waters has pushed speeds to around 15 knots in the Bay and
15-20 knots in the coastal waters. Waves also average 2-3 feet and seas 3-4
feet. Small Craft Advisory conditions not anticipated through the early morning. Little
change in the pattern today with southerly winds generally at or below 15 knots over
the waters. Seas subside to 2-3 feet today and waves 1-2 feet. Southerly flow
increases again tonight...but not as strong as previous nights as
flow becomes more southwesterly. Seas forecast to build back to 3-4 feet...but
remain sub-sca. A cold front will approach the region
Tuesday...crossing the waters late Tuesday night into Wednesday. Strengthening
pressure gradient will result in increasing winds pre-frontal late
Tuesday-Tuesday night...but warm air advection aloft will result in unfavorable lapse
rates. 10-15 knots forecast over the Bay and 15-20 over the coastal
waters. Seas remain 3-4 feet. Flow becomes west-northwest behind the front...but
a weakening cold front/lack of cold air advection will prevent Small Craft Advisory conditions Post
frontal. High pressure builds in behind the front Wednesday...settling
over the waters Wednesday night through the end of the week. As a
result...sub-sca conditions continue through the end of the week with
winds at or below 10 knots and seas/waves at or below 2 feet.
record high temperatures for Tuesday 9/2: