Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
432 PM EDT Wednesday may 6 2015
a weak frontal boundary will drop into southern Virginia tonight
into early Thursday...before dissipating. Low pressure off the
coast of northern Florida and Georgia...will slowly lift
northward and will spin off or near the southeast coast through
Near term /until 6 am Thursday morning/...
latest radar late this afternoon showed scattered showers and a few thunderstorms over
northern/northwest Virginia and drifting south-southeast. These showers and maybe a thunderstorm or two
could move into our northern/northwest counties during this eveng. Have
30%-50% probability of precipitation in these areas...diminishing to slight chance (20%) or
14%-10% as you go southeast toward extreme southeast Virginia and NE NC. Very little deep
layer shear is present...so severe weather is unlikely. But...could be
locally heavy rain in any thunderstorm...due to slow overall storm
movement and precipitable water values into the 1.25" to 1.50"
range. Otherwise...mostly clear to partly cloudy tonight with lows
ranging from the middle 50s to near 60.
Short term /6 am Thursday morning through Saturday/...
Thursday through Sat...going with a blend of the 12z NAM/European model (ecmwf) with regard
specifically to a low pressure area which will slowly lift nwrd and
spin just off the southeast CST. At the same time...surface hi pressure will
slide off the northern middle Atlantic CST and well out to sea.
Expect a partly to mostly cloudy sky through the period with a
gradual increase in dwpts/humidity...due to onshore flow. Only a
slight chance of a shower or thunderstorm in the extreme northwest and extreme south-southeast
counties Thursday afternoon/early Thursday eveng. Hi temperatures ranging through the 70s
NE (upr 60s at ocean city) and along the CST to upper 70s to lower 80s
Will continue to monitor the progress of aforementioned low moving
nwrd just off the southeast CST. Weak flow/upper low closing off over the southeast
CST Thursday night through Sat making for a difficult forecast...slow
movement as the low becomes stacked with height. For akq County Warning Area...we
will be on the northern fringe...with occasional waves of deeper
moisture and modest lift affecting mainly the southern 1/2 of the County Warning Area
late Thursday night through Sat. Have no higher than 20%-30% probability of precipitation into Friday
morng...have 30%-40% probability of precipitation over extreme southern Virginia/NE NC Friday afternoon into
early Friday eveng...then have 30%-40% probability of precipitation over central/southern Virginia and NE
NC Sat afternoon into early Sat eveng. Mainly just 20% or less over
the east-northeast. High temperatures mainly in the 70s near the CST to the lower 80s
well inland both Friday and Sat. Lows get a tad warmer as dew points
rise...ranging from the middle 50s to lower 60s Thursday night...and in the lower
to middle 60s Friday night (altho some upper 50s still possible at ocean
Long term /Saturday night through Wednesday/...
the overall pattern for late this weekend and early next week keeps
a ridge of high pressure in place across the eastern Continental U.S. For
continued warm temperatures. The uncertainty in the forecast has to
do with low pressure currently off the southeast coast...its eventual
track...and how much of an impact it has on the local area. Stayed
close to wpc/NHC forecasts for the end of the weekend/first of next
week which brings the center of the low up into eastern NC on
Monday...then off the Virginia coast on Tuesday in advance of a cold front
that sweeps through the local area Tuesday night/Wednesday morning.
Will allow for scattered shower/thunderstorm chances over the local area sun-
Tuesday...then dry again next Wednesday behind the cold front. Highs through
Tuesday in the 80s...except cooler 70s immediate coast. Lows in the
Aviation /20z Wednesday through Monday/...
VFR conditions prevail across the region this afternoon as high
pressure centered over the western Atlantic continues provide
mainly clear sky expect for some middle level clouds left from
Tuesday afternoon convection and cirrus from low off the Florida coast.
For this afternoon have maintained VFR conditions...but there is a
small chance for scattered convection that is developing off the
higher terrain to the west of the area and could slide east early
this evening. Ric is the most favor location for convection...but
with models showing that anything that forms quickly
weakens...have elected not to include any mention of storms with
just a 20 - 30 percent chance of precipitation falling. This moisture
will linger over the northern portions of the area tonight keeping
some middle deck clouds from ric-sby.
Further to the south...the region is in the subsidence region
from the low off the coast so outside of some thickening
cirrus...not anticipating much in the way of clouds. The winds are
turning some east to southeast this afternoon as the surface high begins to
slide east and the low to the south begins to lift north. But
expect VFR conditions to prevail through the overnight hours.
The VFR conditions are expected to continue into Thursday as a
backdoor front falls apart as it move into Virginia and the low to the
south strengthens. So the flow will become east - NE but any ceilings
should be VFR.
Low pressure lingers off the southeast coast through the coming
weekend...bringing chances for showers and thunderstorms to southeast
Virginia/NE NC Friday through sun.
a weak frontal boundary washes out over the northern middle-Atlantic
by tonight. Meanwhile...surface high pressure remains anchored over
the southern Appalachians. Light southeast flow backs around to the east-NE
tonight...then remains light east on Thursday as high pressure
remains over the mid-Atlantic. Little change is expected through
the weekend with light onshore flow expected to continue. The low
pressure center currently off the southeast coast is expected to only
slowly meander up the Carolina coast through Monday. This will keep
the strongest winds and highest seas south of the local waters.
Right now...seas are only forecast to build to 3-4 feet on
Friday...remaining 2-4 feet through the weekend.