Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 281118

Area Forecast Discussion
National Weather Service Blacksburg VA
718 AM EDT Fri Oct 28 2016

High pressure will build into the region from the northwest today
before sliding southeast to the Carolina coast tonight into
Saturday. The high passes offshore by Sunday allowing a weak cold
front to drop south through the area Sunday night. This will be
followed by high pressure until the end of next week along with
unseasonably warm temperatures.


As of 300 AM EDT Friday...

Surface cold front slowly making its way across the Blue Ridge and
should finally exit eastern sections early this morning. This
will allow a drier northwest trajectory to kick in today as high
pressure builds from the Ohio Valley southeast into the region by
this evening. Will continue to see some upslope driven low clouds
mainly western slopes early this morning before the cool pool
aloft heads east and drier air mixes out any lingering moisture by
midday if not sooner. Otherwise expect subsidence and downsloping
to make for a mainly sunny afternoon through some high clouds.
Given increasing dry advection over dry ground and under sunshine
would again expect high temps on the warm side of guidance espcly
east per northwest downslope and lack of much cool air aloft
behind the front. This supports bumping highs to the 68-74 range
east and mostly low/mid 60s west.

Mainly clear skies should continue overnight as the surface high
shifts overhead before sliding to the southeast late in advance
of the next shortwave passing well to the north. This along with
some increase in upper heights will allow for a quick return of
deepening warm advection aloft as models show around a 5 deg/C
increase in temps at 850 mb overnight. However appears will see
enough decoupling under warming aloft to allow decent radiational
cooling espcly western valleys and out east where will be under
the center of the surface ridge longer. Expect the ridges to stay
more mixed overnight under westerly flow aloft so appears a range
from upper 30s/low 40s to low/mid 50s likely across the area.


As of 330 AM EDT Friday...

Expect temperatures well above normal through the weekend. The polar
jet continues to keep cold air bottled up to our north form the
northern Great Plains to New england, and the low amplitude upper level
pattern is progressive and does not show any evidence of significant
buckling to allow for a cold surge to move south. This will keep high
pressure at the surface anchored to our south with somewhat breezy
conditions as warm and dry west to southwest winds persist across the
Appalachians and central mid Atlantic region.

On Sunday, a short wave trof will move through the eastern US and start
to push a weak front into the area from the north. Guidance has slowed
down the progress of the front and Sunday looks to be dry, with just a
slight chance for a late day shower across far northern Greenbrier
county. As the front sinks southward through the region Sunday night,
the slight chance for a shower will extend a bit further south into
Greenbrier and the Alleghany Highlands but no meaningful chance for
precipitation will make it any further south.

On Monday, cooler high pressure will wedge down the east side of the
mountains behind the front. Guidance is becoming a bit more eager to
squeeze out some precipitation in the wedge but experience of late
indicates that this is over done so will continue with a dry forecast
through Monday night for now.


As of 300 PM EDT Thursday...

The wedge will begin to erode Tuesday with temperatures moderating 10F
to 15F warmer. An upper level ridge centered over Texas will track east
along the Gulf states through most of next week. This ridge will keep
the region dry with any northern stream disturbances tracking east from
the Great Lakes to New England.  Boundaries from a few northern stream
systems may dip far enough south to increase clouds and have a slight
chance for rain for area north of I64 next Thursday afternoon and


As of 650 AM EDT Friday...

Weak cold front currently crossing southeast sections should
finally clear KDAN in the next couple of hours. However will
continue to see local pockets of MVFR to IFR in fog/stratus espcly
around KDAN until mixing increases a bit behind the front early
this morning. Otherwise will continue to see varied cloud bases
over the west with continued periods of sub-VFR likely through
mid morning at KBLF/KLWB/KBCB due to upslope low clouds. Once the
northwest flow upslope weakens and cooler air aloft lifts out,
expect low cigs to quickly fade resulting in a return to VFR
across the region by mid to late morning. Widespread VFR under
some high clouds and west/northwest winds at 5-15 knots then
expected this afternoon into tonight with winds becoming light
after dark.

Extended aviation discussion...

Saturday...VFR with no flight restrictions. Only exception would
be river valley fog in some of the mountain valleys early Saturday
morning which could temporarily impact KBCB and KLWB.

Sunday...VFR. Weak front passing to the north could generate some
MVFR cigs Sunday night. Impact would be mainly to the WV mountains
and western slopes of the VA highlands.

Monday and Tuesday...Mainly VFR. Only exception would be
formation of river valley fog in some of the mountain valleys
which would occur during the 08z/4am to 13z/9am time frame
resulting in a brief period of IFR due to surface based
obscurations at KLWB, KBCB. Some light early morning ground fog
may also occur at KLYH and KDAN but conditions temporary.




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