Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 182300

Area Forecast Discussion
National Weather Service Blacksburg VA
700 PM EDT Wed Oct 18 2017

A large area of high pressure will remain over the eastern part
of the country before slowly sliding off the coast on Saturday.
This will bring us pleasant fall weather through the weekend.
Our chances for rain will then start to increase on Monday as a
strong cold front approaches from the west.

As of 250 PM EDT Wednesday...

More pleasant fall weather is on tap through tomorrow as a large
area of high pressure remains in place across the eastern US.
Temperatures tonight will be a bit warmer than last night with
mid/upper 30s east of the Blue Ridge, low/mid 30s west with cooler
readings in the valleys and some patchy frost and fog once again.
Lots of sun with some high clouds for Thursday with highs in
the middle 70s east to upper 60s/lower 70s west.

As of 257 PM EDT Wednesday...

Surface high overhead Thursday night will slowly lift northeast to
off the mid-Atlantic coast by Friday into Saturday as upper pattern
amplifies with 5h ridge over us keeping us dry with warming trend.
Ridge axis moves offshore by late Saturday allowing some mid/upper
level clouds to increase by Sat night.

Lows Thu night will range from the upper 30s to lower 40s over most
of the area, with some mid to upper 40s urban areas and well mixed

Highs about 5-10 degrees above normal Friday under sunny skies in
the 70s.

Slightly milder Friday night with 40s CWA wide.

Same temps again Saturday and milder Sat night with lows in the mid
40s to around 50.


As of 157 PM EDT Wednesday...

Major amplification of the upper pattern this period, though still
differences in speed of the sfc front and upper trough. The 00z
ECMWF more progressive than the 12z GFS. Allowed for a little faster
than the GFS but given the highly amplified nature things could be a
little slower.

With this in mind should see warmer and more humid conditions ahead
of the front Sun-Mon with rain chances arriving Sunday night with
more showery coverage Mon-Mon night. Some stability indices suggest
slight potential for thunder Monday. Arrival of cooler air as upper
flow deepens over the central Appalachians. A bit of a winter like
setup Tue-Wed with upslope showers. Colder air with the trough may
allow for snowflakes in the higher ridges late Tuesday with
brisk/breezy conditions Wednesday.

Highs in the 70s Sunday and Monday (though Monday could be cooler if
rain comes in faster), drops to highs in the 50s, maybe even 40s by


As of 655 PM EDT Wednesday...

High pressure will remain in control with VFR flight conditions
expected tonight through Thursday under some passing high clouds.
Only exception will be possible IFR conditions in nocturnal
fog/stratus developing in the valleys. Latest HREF guidance
suggests best potential for dense fog around KBCB late and a bit
less at KLWB at this point. However based on last night will
continue to only use a TEMPO group around daybreak at KBCB and
leave it out of KLWB for now. Brief fog also possible around
KLYH/KDAN toward dawn but not enough to include mention at this
point. Winds will again be light overnight.

Once any low clouds/fog dissipate Thursday morning, expecting
another day of widespread VFR under southwest winds at 5-10 kts.

Extended Aviation Discussion...

High pressure will remain over the region through Sunday with
generally VFR conditions expected, outside the usual late
night/early morning patchy river and mountain valley fog.
Moisture returns ahead of an approaching cold front later
Sunday night into Monday when the threat for showers along with
sub-VFR should increase by early next week.




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