Area Forecast Discussion
Issued by NWS Blacksburg, VA-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KRNK 241510
Area Forecast Discussion
National Weather Service Blacksburg VA
1010 AM EST Tue Jan 24 2017
Low pressure system just offshore of Atlantic City will move
northeast today, yielding coastal rain and inland snow from New
York to Maine. In its wake, a period of strong northwest winds
will occur across the Mid-Atlantic states. High pressure will
build across the Mid-Atlantic region by tonight, skies clearing
and winds diminishing. Southwesterly flow will develop on the
back side of the High on Wednesday with well above normal
temperatures. Wednesday will be the last day of warmth this
month. A large cold upper level trough of low pressure will
settle over the eastern two thirds of the continental U.S. from
Thursday through the end of the month bringing a return to near
seasonal January temperatures, which is highs in the 30s and
lows in the teens and 20s.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 1110 AM EST Tuesday...
Little change in the early morning forecast philosophy with this
update as our area remains sandwiched between the departing low
pressure system tracking northward off the DelMarVa Coast and
high pressure over TN/KY.
Temperatures today will be warmest across the piedmont where
return of sunshine will allow for readings to climb into the
50s. Did adjust temperatures a degree or two upward during the
morning across the foothills of northern NC where downsloping
off the Blue Ridge is pushing temperatures a few degrees higher
than anticipated. Mountain counties west of the Roanoke Valley
and across the NC high country will continue to see lingering
clouds through much of the day keeping temperatures from getting
no higher than the 40s.
Winds will be the strongest across the higher elevations today,
especially along the Blue Ridge Parkway southwest of the Roanoke
Valley and into the NC High Country. Wind gusts along this
strip of real estate will gust close to 50 mph today. Blustery
conditions will also be found across the lower elevations with
occasional gusts of 25 to 35 mph.
By tonight, High pressure will begin to take firm control. Any
lingering cloudiness over the mountains is expected to dissipate
during the overnight with clear skies anticipated across the
entire CWA after midnight. Winds will also diminish, decoupling
after midnight in the valleys allowing for temperatures to
reach freezing. Higher elevations will begin to pick up a
southwest wind toward daybreak Wednesday, so temperatures across
the ridges should remain above freezing and may even begin to
rise before sunrise. 850 mb temperatures are forecast to rise to
near +10 degrees C by daybreak Wednesday. This will set the
stage for a fast warm up Wednesday once the inversion breaks
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.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
As of 330 AM EST Tuesday...
High Pressure and upper level ridging will bring very warm
temperatures to the region Wednesday. Temperatures will run around
20F warmer than normal with widespread 60s across the forecast area
to possibly 70F in Southside VA.
A disturbance will track east of the Great Lakes Wednesday night,
allowing a cold front to enter the mountains around midnight. This
front will jump to a weak lee trough Thursday morning. With limited
moisture, rainfall amounts should not exceed a quarter of an inch
with lesser amounts along the Blue Ridge and foothill counties.
Cooler air will slowly filter into the region Thursday with daytime
highs topping out with values closer to normal. Daytime highs across
the mountains should occur during the morning with temperatures
remaining steady or slowly falling during the afternoon. Higher
elevation will gradually see rain changing to snow through the day
with little to no accumulations. By Thursday evening, the cold front
is moving off the east coast and a positive-tilted trough tracks
across the Ohio Valley. Westerly flow and trajectories from the
Great Lakes, accumulating snow of a couple of inches are possible
along western slopes and higher elevations. Not much moisture will
gets past these western slopes Thursday night into Friday morning,
therefore only a dusting is possible into the New River Valley. The
upper level trough will dig into the Tennessee Valley Friday
afternoon, increasing the likelihood of snowbands reaching the Blue
Ridge. Even though cold, accumulations during the day Friday maybe
limited from increasing sun angle. High temperatures Friday will
range from the mid 20s to lower 30s west to lower to mid 40s east.
Also accompanying the cold air in the wake of the front will be
strong and gusty winds Thursday and Thursday night.
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
As of 330 PM EST Monday...
Our 500 mb height pattern begins to change in the mean to one of
cyclonic flow aloft late in the week through early next week. Such a
pattern lends itself to relatively unsettled weather conditions and
cooler temperatures - to values near or slightly below late-January
Indications from today`s global models continue to point to a rather
long duration northwest flow upslope snowfall starting Thursday
evening into the weekend, and strictly limited to the favored
western-facing hillsides in southeastern West Virginia, far
southwest Virginia and the high country of North Carolina. It does
appear that some light accumulations of snow would be possible
through much of this period. How much snow still remains in some
question as periods of more persistent snow would be governed to
some extent by embedded shortwaves in the broader cyclonic flow, and
largely westerly continental flow would also serve to keep available
Outside of these upslope areas however, at this point it appears to
be a largely cooler and dry period with highs generally in the 30s
to low 40s and lows in the 20s.
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
As of 600 AM EST Tuesday...
Narrow ribbon of moisture from central WV into southwestern VA
will maintain a band of showers across southeast WV into the
mountains of southwestern VA, including the New River Valley
vcnty of KBCB. Elevations above 3000 feet were experiencing some
snow, with mainly rain below 3000 feet. Widespread IFR cigs were
found across the OH Valley and into the mountains and associated
with the rain and snow. East of the mountains cloud bases were
generally VFR, and little or no precipitation was making it over
Strong Low pressure near the New England coast will gradually
move away from the central Appalachians today. This will result
in gradually improving cigs with any precipitation coming to an
end this afternoon.
Winds will be gusty today. Strong cross barrier northwest flow
in the wake of the departing storm system will result in surface
gusts of 25 to 30 kts today. Ridgetop winds may gust to 45 kts.
By tonight, High pressure will build overhead, winds diminishing
and any lingering cloudiness over the mountains dissipating.
Widespread VFR is anticipated for Wednesday.
Extended Aviation Discussion...
High pressure will move east of the area during the day
Wednesday, warm southwest winds developing on the back side of
the high. A band of MVFR showers is possible along/behind a
cold front Thursday into Thursday night. Colder west to
northwest wind flow will develop behind this front with mountain
snow showers likely for the weekend associated with MVFR
VA...Wind Advisory until noon EST today for VAZ015>017.
NC...Wind Advisory until noon EST today for NCZ001-002-018.