Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
703 am EST Wednesday Feb 10 2016
an upper level trough lingers across the region through tonight.
High pressure returns later tonight through Thursday night. Weak low
pressure lifts along the southeast coast Friday and pushes off the
southeast coast Friday night. Arctic high pressure builds in for the
Near term /through tonight/...
current analysis indicating ~995 mb surface low pressure well off the
middle Atlantic coast. Aloft...rather potent shortwave is currently
moving east through central Virginia...and is pushing towards the Eastern
Shore. Earlier scattered/numerous snow showers are now pushing
through the peninsula and points north west of the Bay...and will become
confined to the Eastern Shore in the next hour or two. Have had a few
reports of around 0.5" snow across the area including 0.4" at ric
Airport. Some brief moderate snow showers will likely put down a
dusting of snow across the Eastern Shore through 9 or 10 am as
temperatures average in the upper 20s to lower 30s. Will continue to mention
this in the severe weather potential statement. Otherwise...variably cloudy skies today...more
clouds than sun on the Eastern Shore...more sun than clouds across south
central Virginia and NE NC. Chilly northwest flow will bring highs from around
40 f across the north to the middle 40s south (as with the past few
days mav numbers seem a few degrees too warm).
Trough axis aligns along the middle-Atlantic coast tonight as
additional shortwave energy dives down the back side of the upper
trough. Expect mostly dry conditions as precipitable waters will be at or below 0.10
inches...but as colder air spills in...could see a few Bay
enhanced snow showers across mainly the Virginia Eastern Shore so will
maintain 20-30 probability of precipitation there (should be too dry elsewhere as dew points
will be very low but could see some flurries). Cold tonight with
lows in the upper teens Piedmont where skies clear earlier to middle
20s along the coast and Eastern Shore.
Short term /Thursday through Friday night/...
dry/cold Thursday as the trough axis pushes offshore...ushering in
an even colder and drier Arctic air mass. Highs generally in the
low/middle 30s...or -1 to -1.5 Standard dev. Sky averages sunny to mostly
High pressure settles over the region Thursday night and Friday as
additional energy digs over the Midwest into the Gulf states.
Associated area of low pressure prognosticated to develop off the southeast
coast Friday...with a chance for snow across the southeast late
Friday. Due to clouds and a cold start...expect highs to stay in
the lower to middle 30s. Have bumped probability of precipitation up to 40-50% across NE NC and
20-30% across far southern/southeast Virginia given trends in GFS/NAM. Could see
some accumulation across NE NC but uncertainty in track remains.
Long term /Saturday through Tuesday/...
strong cold front crosses the region through the day on Saturday.
Behind the front...Arctic airmass is ushered into the mid-Atlantic.
Strong upper level dynamics may be enough to form a few snow shower
Sat morning. Wrap around moisture from weak area of low pressure
developing off the coast of the Carolinas may bring a slight chance
for -sn/-rasn across NE NC.
Strong cold air advection continues through the day on Sat with
925mb temperatures dropping 10c through the day. Thicknesses and
temperatures aloft continue dropping through the weekend as upper
trough swings across the area and surface high pressure builds
west...centering over the Great Lakes region. Expect high temperatures in
in the upper 20s northwest to the middle 30s southeast. Coldest airmass of the
season settles in Sat night with lows dropping into the single
digits and low teens Sun morning (lows over 20f below normal).
Wind chill advisories may be needed for portions of the area. Expect
highs in middle/upper 20s on sun with temperatures falling back into
the teens Sun night.
Active weather patterns continues for the beginning of the work
week. With the surface high pressure moving off the coast...another
potent upper trough swings across the deep south. This will help
form an area of low pressure across the southeast U.S. That will move NE
late Monday into Tuesday. Uncertainty exists with this feature due to
slight model differences in timing of low development and track of
low. The models do suggest a multi-precipitation type event with an
onset of winter precipitation transitioning to a mix on Tuesday. Precipitation
prognosticated to move NE off the coast by Tuesday night
Aviation /12z Wednesday through Sunday/...
expect mainly VFR conditions today into Thursday morng...with broken or
overcast SC (3000-6000 ft) at sby esply. Also...light snow shower
possible (sw-) at sby...but did not include in taf. Scattered to broken SC
and ac likely at phf...orf...and ecg through this period. West winds
between 10-15 kts with gusts to near 20 kts possible across the
region today into tonight.
Outlook...VFR conditions will prevail Thursday into Friday morng...as hi
pressure builds into the middle Atlantic region. Shortwave energy in west-northwest flow aloft
coupled with weak low pressure moving across the Carolinas and off the
CST...could produce light snow or flurries (lwr ceilings/vsbys) from
midday Friday into early Friday night...esply across southern Virginia and NE NC.
moderately strong pressure gradient and continual shots of cold air
aloft will help strengthen west or northwest flow over the waters today through
Thursday night. The result will be prolonged Small Craft Advisory conditions across the
waters...with the rivers Small Craft Advisory conditions starting this eveng. Expect
wind gusts to average 25-30 knots this morng through Thursday night over the
coastal waters...and 20-25 knots over the ches Bay. Expect seas 3 feet
nearshore to up to 5 feet 20nm off the CST with the offshr flow.
Weak area of hi pressure settles over the middle Atlantic region by Friday
morng...allowing for a brief period of non-Small Craft Advisory conditions.
Then...strong Arctic front prognosticated to cross the waters during Sat.
Gale conditions will be possible late Sat into sun...as strong
cold air advection advection takes place and surface pressure gradient tightens between
departing low to the NE and bldng hi from the northwest. A period of
freezing spray will also exist...as temperatures will quickly drop into
the 20s and teens sun morng...with winds gusting over 30 knots. Winds
diminish quickly later sun into Sun night...as the surface hi centers
over the waters.
river Flood Warning remains in effect for the Nottoway at Sebrell.
See flsakq for details.
all coastal flood warnings have been discontinued...and have been
replaced with advisories through the upcoming high tide cycle
(later this morning ocean/Lower Bay...to through the afternoon across the
With west-northwest flow...departures are falling...now average around 1.5 feet.
This is still enough for minor flooding through the upcoming
cycle...although may fall just short of minor flood thresholds for
the west side of the Bay and rivers.
Maryland...coastal Flood Advisory until 7 PM EST this evening for
Virginia...coastal Flood Advisory until 1 PM EST this afternoon for
Coastal Flood Advisory until 5 PM EST this afternoon for
Marine...Small Craft Advisory until 1 am EST Friday for anz634-650-652-
Small Craft Advisory from 10 PM this evening to 10 PM EST
Thursday for anz635>638.
Small Craft Advisory until 10 PM EST Thursday for anz630>633.