Area Forecast Discussion
Issued by NWS Blacksburg, VA
FXUS61 KRNK 280109
Area Forecast Discussion
National Weather Service Blacksburg VA
909 PM EDT Thu Oct 27 2016
A weak cold front will move through the region this evening. High
pressure will build across the region for Friday into Saturday.
Another weak cold front will move through the area Sunday. This
will be followed by high pressure until the end of next week along
with unseasonably warm temperatures.
.NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 900 pm EDT Thursday...
A weak cold front continues to move through the region. Evening
soundings indicates uniform westerly winds aloft, which is
prohibitive of showers per downslope drying. Actual surface wind
will come around to the northwest with the passage of the front,
which will take place across the mountains between now and
midnight...then east of the mountains after midnight. Can`t rule
out a brief sprinkle with the passage of the front, but synoptic
lift and any lingering thermodynamic lift is all but gone. Until
the front passes, there may be some patchy fog across southside
va and piedmont of NC. Temperatures vicinity of Danville and
Reidsville and Mount airy have dropped close to the dewpoint
values. This may allow for fog formation, but think this will be
temporary. Once the front moves through during the late night,
mixing should commence and disperse any fog/haze.
Behind the front, upslope clouds and a few sprinkles may persist
across the western areas, with clearing across the east. There
may be a period of low end gusty winds west of the Blue Ridge
with the passage of the front, but the stronger 850mb winds are
lifting north of the area overnight. Given that the post-frontal
air mass is mainly continental Pacific, 850mb temps actually begin
to rise, not fall behind the front Friday. Clouds overnight and
turbulent mixing along with little to no cold advection should
yield temperatures well above freezing.
Clouds will decrease in the western mountains by mid-morning
Friday leaving most of the CWA clear by early afternoon if not
sooner. With greater insolation and slightly warming temperatures
at 850mb Friday, expect afternoon maximum temperatures to be on
par with readings experienced today, likely warmer across the
Piedmont. Bottom line is that temperatures will continue to remain
well above normal for the foreseeable future.
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 230 PM EDT Thursday...
Surface high pressure will track south across the region Friday
night and Saturday. This high pressure system along with heights
increasing aloft will keep the region dry Saturday with high
temperatures warming 10F-15F above normal. Flow aloft becomes zonal
Sunday resulting in similar high temperatures as Saturday. Normal
high temperatures for late October range from the lower 60s across
the mountains to mid to upper 60s across the foothills and piedmont.
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 300 PM EDT Thursday...
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 Sunday afternoon and
evening and again next Thursday afternoon and night.
Cool air will wedge south across the region Monday with temperatures
warming to near normal. This wedge will begin to erode Tuesday with
temperatures moderating 10F to 15F warmer
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
As of 900 PM EDT Thursday...
A weak cold front will cross the forecast area overnight.
Little or no precipitation is associated with the front.
Conditions will remain primarily VFR with the exception of the
western slopes vcnty of KBLF and KLWB where MVFR cigs will develop
after the frontal passage (after 03z/11PM). Some light MFVR fog is
possible across the piedmont of VA/NC early tonight. With the
passage of the front the fog is expected to disperse. Some
guidance suggests that visibility at LWB could become IFR late
tonight (due to fog formation along the river), however, enough
uncertainty exists to just entertain tempo group for now. Post
frontal winds should prohibit fog formation in spite of the model
For Friday, widespread VFR is anticipated. Any lingering
cloudiness along the western slopes of the Appalachians is
expected to erode, leaving widespread VFR conditions for the
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.