Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
346 PM EDT Sat Aug 1 2015
a weak boundary crosses the area tonight. High pressure builds over
the region Sunday through Monday. The next cold front moves across
the area Tuesday.
Near term /until 6 am Sunday morning/...
showers over Albemarle sand have dissipated. Showers ivof surface T rof
across Maryland expeceted to continue into the evening.
Weak surface boundary / trough prognosticated to cross the area tonight with
surface high prs over the mts. Models showing a bit more moisture assctd
with the trough passage...most notable across the Northern Neck on NE
across the lower Maryland Eastern Shore where isolated showers have been added.
Temperatures drop nicely given the lower deep temperatures. M clear south to pt cloudy
north. NAM suggests some patchy fog dvlpng over the northwest Piedmont
aftr midnight mainly northwest of ric. Lows M-u60s west of the ches Bay...
u60s- l70s coast.
Short term /6 am Sunday morning through Tuesday/...
500 mb ridge to dominate sun and Monday but models continue to show a
weakness across eastern NC ivof Albemarle sand that just may be enough
trigger for scattered diurnal convection across xtreme southeastern Virginia / NE NC
sun then expanding a bit to the southeastern half of forecast area Monday. Otw...pt to
mostly sunny both days with above normal temperatures. 850 mb temperatures sprt highs
sun in the u80s-l90s with l-m90s Monday. Lows m60s-l70s.
Models differ a bit with respect to the available moisture and timing of the next front
across the region Tuesday. Latest trends are for a daytime frontal passage with not
much moisture available until aftr 18z...but by then the greatest sprt for
convection to develop shifts south into NC. For now...kept slght chance
probability of precipitation in grids. Anthr hot day with highs in the l-m90s.
Given the forecasted deep temperatures...heat index values top out around 100 both
Monday / Tuesday.
Long term /Tuesday night through Saturday/...
long term period will feature frequent chances of rain with
decreasing temperatures through the period. Tough to time exactly when best
chances will be but the forecast calls for a 30-40% chance of
rain showers/thunderstorms each aftn/eveng...and a 20-30% chance each night/morng.
Pattern will feature an upper-level trough over the far eastern Continental U.S. With
transient shortwave troughs passing through the middle Atlantic region. As for
temperatures...highs will drop from the low/middle 90s Wednesday to middle/upper 80s Friday and
Aviation /19z Saturday through Thursday/...
a weak trough/frontal boundary will linger along the coast today...
especially across NE NC. VFR conds expected through the taf period with
mostly light southeast-SW wind. Kecg and ksby may experience broken ceilings in
the afternoon/evening as the boundary gets pushed offshore. Skies
gradually clear overnight as high pressure builds into the middle
Atlantic region through Sunday. Another trough crosses the area on
Monday...followed by more high pressure.
sub-Small Craft Advisory conds expected this weekend. A weak front/trough of low pressure
approaches from the northwest this aftn/eveng. A weak southerly surge is expected
over the Bay ahead of the front...but winds are expected to stay just
below Small Craft Advisory thresholds (~15 kt). The front slides offshore and weakens
into Erly sun...with winds sun at or below 10 knots and seabreezes developing.
Waves over the Bay 1-2 feet and seas over coastal waters 2-3 feet. Southerly flow
returns by Monday...with 10-15 knots winds over the Bay/rivers/sound and
15-20 knots over coastal waters. Seas over northern coastal waters may approach 5 feet
late in the day into Monday night. Weak hi pressure returns to the region
Tuesday through Wednesday with S-SW winds at or below 15 knots and waves 1-2 feet/seas 2-4