Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 211459

Area Forecast Discussion
National Weather Service Blacksburg VA
1059 AM EDT Fri Oct 21 2016

A strong cold front will move across the Mid-Atlantic Region
today. Behind the front there will be a noticeable change with
blustery northwest winds ushering in much cooler temperatures for
the weekend.


As of 1055 AM EDT Friday...

at 10AM a strong cold front extended from the Maryland panhandle
into the foothills of Virginia and North Carolina. The front was
moving quickly east and will east of Buckingham and Danville by

Showers will accompany the front, although not much qpf. Rainfall
amounts will range from a quarter to a half an inch in the
mountains, but the shower activity is expected to dry-up as the
front moves east. The development of strong downward motion lee
of the mountains resulting in a fraction of the qpf across the
piedmont, with rain totals of a tenth of an inch or less.

Main weather focus for the afternoon and evening will be the
development of moderately strong northwest wind and falling
temperatures. Wind gusts will range from 25 to 40 mph. Models
suggest the pressure gradient may be strong enough to support some
40 to 50 mph gusts for elevations above 4000 feet by late this

Accompanying the increasing wind speeds will be falling
temperatures. Cold air advection behind the front will result in a
noticeable change with both temperature and dewpoints taking a
tumble. By sunset, readings will be in the 40s west of the Blue
Ridge and 50s across the Piedmont, a 30 degree change compared to
yesterday. Dewpoints will be lower yet with readings in the 30s.
Folks heading out for Friday high school football will certainly
need an extra layer or two, wind chills in the 30s.

Temperatures will continue to tumble through the overnight tonight
with lows in the 30s across the mountains by daybreak Saturday,
and 40s across the piedmont. Clouds will linger across the
mountains with the potential for some sprinkles of flurries for
the higher elevations, elevations above 4000 feet having the best
chance for seeing snowflakes as temperatures dip to near freezing.
Anyone camping in the mountains tonight will can expect wind
chills by daybreak Saturday in the 20s, and wind chills as low as
the teens for elevations above 4000 feet.


As of 400 AM EDT Friday...

Saturday morning, the area will still be under the influence of a
sharp pressure gradient between the upper low situated over eastern
Pennsylvania and an upper ridge building across the central United
States. Magnitudes differ from model to model, but a consensus would
be somewhere in the neighborhood of an 850mb 30 to 40 kt wind across
the area in the morning, that loses little momentum throughout the
day. This flow will yield upslope cloud cover across southeast West
Virginia, south into the Northern Mountains of North Carolina. Rain
showers, and some isolated snow showers at higher elevations, are
expected during the morning across primarily southeast West
Virginia. By the afternoon, coverage will have decreased and
temperatures will have warm enough for an end to the localized areas
of snow showers. Little or no snow accumulation is expected on the
ground given how mild the area has been this past week. Any dusting
of snow will be confined to elevated surfaces. Wind gusts at the
surface will average 25 to 35 mph across the mountains with some
isolated gusts approaching 40 mph at highest elevations. Across the
Piedmont, gusts of 15 to 25 mph will be more common. Freezing
temperatures will continue for a few hours after sunrise, mainly at
elevations at or greater than 4000 feet MSL. High temperatures on
Saturday will average the mid 40s to around 50 across the mountains,
with the highest elevations around 40 degrees. Across the Piedmont,
highs of the mid 50s to around 60 are expected.

By Saturday night, the precipitation is expected to have ended, but
a comparable 850 mb wind is anticipated. While areas east of the
crest of the Blue Ridge are expected to decouple with limited gusts
reaching the surface, ridge tops and channeled mountain valleys will
continue to experience gusty through the night, but likely trend
weaker as the night progresses. Low will range from the mid 30s to
around 40 across the mountains, with the highest elevations around
freezing. Across the Piedmont, expect lows in the upper 30s to lower

Sunday into Monday, winds will trend weaker as the upper low slowly
heads east into the Canadian Maritimes and the axis of the upper
ridge makes gradual progress eastward as well. Anticipate the
synoptic pattern across the area to become zonal with primarily a
dry forecast. A shortwave trough moving through this pattern across
the Great Lakes region will bring a relatively dry cold front
through the area Monday. Isolated showers are forecast for western
Greenbrier county only at this time. Temperatures will rebound by
Monday to high temperatures ranging from the upper 50s to lower 60s
across the mountains with upper 60s to lower 70s across the
Piedmont. Low temperatures Monday night will be five to ten degrees
cooler to those of Sunday night thanks to the aforementioned passage
of the cold front. Across the mountains mid to upper 30s are
forecast with readings around 40 to the lower 40s across the


As of 500 AM EDT Friday...

Zonal flow will across the lower 48 will promote a rather dry
week with few temperature extremes. Not until late Thursday does
another front organize over the midwest and begin advancing
eastward. This front looks to arrive early Friday with timing not
too dissimilar to tonights frontal passage and again with best
dynamics and deeper moisture to our north.


As of 530 AM EDT Friday...

Strong cold front will cross the mountains this morning, then east
across the piedmont this afternoon. Showers will accompany the
front with potential for ifr/mvfr cigs and mvfr vsbys. Passage of
the front will bring falling temperatures and increasing
northwest winds with surface gusts of 20 to 35 kts.

Once the front moves east of the area this afternoon, skies will
clear with the exception of the mountains. Low clouds will linger
over the mountains through early Saturday with likelihood of sub-
VFR cigs.

Extended aviation discussion... flight restrictions anticipated east of the Blue
Ridge. Lingering MVFR cigs likely in the mountains. Winds
gradually diminishing.

Sunday and Monday...Widespread VFR. No flight restrictions.

Tuesday and Wednesday...Potential for river valley fog in the
mountain valleys with local vsby restrictions between 08-14z each
morning, otherwise widespread VFR.




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