Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
153 PM EDT Wednesday Aug 27 2014
high pressure remains over the Appalachians today as Hurricane
Cristobal passes well offshore of the North Carolina Outer Banks.
A weak cold front sags south across the area Thursday...then
stalls across North Carolina Friday before returning north as a
warm front Friday night and Saturday.
Near term /until 6 PM this evening/...
fog has finally dissipated and low stratus over southeast Virginia/NE NC is
breaking up into stratocumulus. Clouds will continue to scattered
out through the rest of today. Meanwhile...hurricane Cristobal's
center of circulation is now located about 300 miles southeast of
Cape Hatteras. Although Cristobal is currently tracking NE at this
hour...the tropical cyclone will begin more of a northward path this
afternoon. Outer bands of cumulus clouds/isolated showers are rotating
into the Outer Banks this morning but are not expected to move
into NE NC due to the shift in Cristobal's storm track later
today. The rest of the area will be dry under mostly sunny
skies...with increasing high clouds from the northwest late this
afternoon due to an approaching cold front. High temperatures will be
more seasonal with readings in the middle-upper 80s/lower 80s
Short term /6 PM this evening through Friday/...
apprchg cdfrnt will help to kick Cristobal NE and further away from
the coast tonight. Models show convection with cdfrnt dsptg across
northern and western Virginia this evening with only limited moisture with the boundary
as it crosses the forecast area late tonight and Thursday morning. Othr than some
clouds...kept a dry frontal passage across the region tonite. Lows 65-70.
Boundary slows as it moves toward the Virginia/NC brdr Thursday afternoon.
Models offering up different solutions with respect to to how much moisture is available
for scattered convection to develop along it as it drifts south into northern
NC. GFS the wettest with the NAM/sref rthr dry. For now...best
sprt for isolated diurnal convection would be across southern third of forecast area
(mainly S of rt 460). High Thursday 85-90...xcpt l-m80s Eastern Shore
areas. Lows Thursday night in the 60s.
High prs moves across northern states Friday with boundary stalled over NC.
Again...some disagreement as to when the boundary begins to move
back north as a warm front. GFS is quicker...NAM/sref slower with
the European model (ecmwf) a compromise. Thus...expect isolated convection across southern
tier counties late. Dry north. Highs 80-85 north...M-u80s south.
Long term /Friday night through Tuesday/...
surface hi pressure exits off new eng Friday night...then becomes nearly
stationary in vicinity of west-central Atlantic through the weekend. A surface warm front
lifts north across the forecast area Friday night through Sat morning west/ possible isolated precipitation.
Otherwise...balance of the period from Sat through sun will be pc...warm and
more humid. A weakening cold front slowly approaches from the west-northwest late sun.
Incrsg moisture ahead of that fnt will lead to a gradual increases
clouds and probability of precipitation by late sun (w)...then across the rest of the forecast area into
Monday. Low amplitude ridge aloft to remain in place in vicinity of southeast Continental U.S. States
early next weak...resulting in continued warm/humid weather over the region for
early Sep. Hi temperatures mainly in the u80s to around 90f inland Sat/sun...
l/m80s at the CST. By Mon/Tue...hi temperatures mainly in the M/u80s. Low
temperatures through the period from the u60s to l70s.
Aviation /18z Wednesday through Monday/...
VFR through the 18z taf period for most taf sites with Hurricane
Cristobal passing well offshore and weak surface hi pressure locked in
place over the middle Atlantic region tonight. Aside from some scattered cumulus at
~2-5k feet this afternoon...not expecting much in the way of cloud cover
due to subsidence around Cristobal. North/NE winds of 5-10 knots this
afternoon will become light/calm overnight. Did include some IFR at sby where
it is most favorable...and with a simlar current temperature/dewpt spread
as yesterday plus sky clear and light winds expected...low visibilities are
likely. Improving conditions are expected after 13-14z. Weak cold
front drops through the area Erly Thursday...with winds becoming northwesterly yet still
at or below 10 knots.
Outlook...mainly dry weather with VFR conditions into the upcoming
weekend. High pressure builds back into the NE/middle Atlantic region
Fri/Sat. Some potential for early am fog or low clouds between
06-12z both Fri/Sat.
surface high pressure extending from southern New England to the middle MS valley
continues the persistent NE pressure gradient across the waters
through today. A weak cold front will slip S across the waters
tonight into Thursday morning. That front stalls just S of the waters by
Thursday afternoon/night while high pressure slides east into New England.
Most speeds over the waters remain sub-Small Craft Advisory through the end of the
week. Another increase in seas (highest southern portion...possibly to
7-9 ft?) Will occur today into Thursday as Hurricane Cristobal passes
After continued NE winds today...most of the waters will see winds
shift to offshore by late tonight. Once weak surface boundary slips S
across the waters Thursday...direction becomes north-NE then east into Friday (w/ a
possible surge in speeds to just below low end Small Craft Advisory...especially northern
portions Thursday morning). A transition from onshore winds to mostly S
occurs this weekend as high pressure sets up off the coast.
Maryland...Beach hazards statement until 8 PM EDT this evening for mdz025.
Air quality alert until midnight EDT tonight for mdz021>025.
NC...beach hazards statement until 8 PM EDT this evening for ncz102.
Virginia...Beach hazards statement until 8 PM EDT this evening for
Marine...Small Craft Advisory for hazardous seas until 6 PM EDT
Thursday for anz650-652-654.
Small Craft Advisory until 6 PM EDT Thursday for anz656-658.