Area Forecast Discussion
Issued by NWS Blacksburg, VA-- Remove Highlighting --
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FXUS61 KRNK 191508
Area Forecast Discussion
National Weather Service Blacksburg VA
1008 AM EST Sun Feb 19 2017
An upper low will cross the region this morning before exiting
to the southeast this afternoon. High pressure builds in from
the north behind this system tonight and remains into Monday
night. A weak frontal system will approach from the west by
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 1000 AM EST Sunday...
No major updates to the forecast this morning. We are still
expecting cloud cover to persist across the western sections of
the region through at least the remainder of the morning, and
mostly likely some hours this afternoon. What remains a question
is if areas near a line from Tazewell, VA to just west of
Lewisburg, WV will see any breaks in the cloud cover today. From
a look at regional weather observations and area web cams, looks
like a good call to maintain some patchy fog and drizzle across
this similar region into the afternoon, and also parts of the
Northern Mountains of North Carolina. Have also tweaked hourly
temperatures and dew points heading into the early afternoon
based upon the latest observations and expected trends into the
As of 215 AM EST Sunday...
Upper low will continue to pivot across the region early this morning
before exiting to the southeast by afternoon. Trailing deformation band
currently producing a band of showers across the far northwest should
also gradually shift east while slowly stretching/dampening out after
daybreak as the associated upper support pulls away. However decent
northwest flow in the wake of the upper system likely to keep low
clouds trapped over much of the west to start with some showers
northwest, and perhaps spotty light rain/drizzle elsewhere along the
far western ridges early on. Subsidence to gradually increase this
afternoon as ridging to the west starts to shift east and ongoing cool
advection weakens. This should help to erode the low cloud canopy over
the mountains with guidance profiles showing moisture pulling back to
the west allowing for mainly sunny skies east and decreasing clouds
west. Just how fast this occurs the key to high temps as MOS has
trended cooler western sections while keeping things quite mild east
per downslope under more insolation. Therefore edged highs from the
Blue Ridge west down a little with some spots likely staying in the 50s
espcly if clouds hold longer under a gusty northwest breeze.
Strong upper ridging to build in overnight as surface high pressure
bridges in from the north by daybreak. Models depict very strong
warming aloft as the next round of warm advection to the west
shifts east. Expect better subsidence to keep skies mainly clear
although some potential for low clouds to again get trapped
over the far west beneath the inversion aloft as warming comes
in above. Otherwise appears a bigger range in low temps from 30s
valleys to perhaps mid 40s at elevation likely with good
radiational cooling outside of warming aloft.
-- End Changed Discussion --
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
As of 208 AM EST Sunday...
An upper level ridge and lots of sunshine will allow Monday`s
temperatures to reach into the upper 60s to lower 70s. These
temperatures are 20F-25F warmer than normal. Records could be broken
at Bluefield and Blacksburg Monday. A light east wind will
keep Roanoke, Lynchburg and Danville from reaching their records.
The upper level ridge will slowly exit the region Tuesday. This
ridge is stubborn and has, by model standards, been slowing the
arrival of our next chance for rain, now set for Tuesday night. Dew
points recover quickly into the 40s Tuesday night, however, dry
prefrontal environment and the lack of lift will limit rainfall to
under a quarter of an inch. The front that will bring the rain is
weak and will likely washout over North Carolina Wednesday.
A reinforcing shot of cool easterly flow and increasing cloud cover
will keep temperatures in the low to mid 60s Tuesday. Despite
Tuesday being cooler than Monday, temperatures will still be 15F
warmer than normal. Temperatures will rebound Wednesday as the
washed out front gives way to warm southerly flow.
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
As of 230 AM EST Sunday...
Residual moisture with the weak front across the region looks
to dry up Wednesday night into Thursday as ridging re-
establishes over the southeast states. This leads to a more
amplified 500 mb pattern for the end of the week with a
deepening trough moving across the central United States and
more spread showing up in the models by that time frame.
Increasing southwest winds Thursday into Friday will increase
moisture and keep temperatures way above normal ahead of the
front with 60s to near 70 likely west and well into the 70s
east. Timing of the frontal passage across the Appalachians
looks to be on Saturday morning with precipitation along and
ahead of the boundary at this point.
Colder air comes in behind the front for the end of the
weekend but again not overly impressive and likely limited in
duration per latest warmer 19/00z ECMWF. However the
combination of a modest low level jet and strong cold air
advection will result in strong gusty winds behind the front
into late Saturday with a brief return to more normal temps to
start the weekend.
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
As of 545 AM EST Sunday...
Axis of lower cigs remains along and west of the Blue Ridge
early this morning with overall MVFR from KLWB to KBCB and IFR
around KBLF where patchy MVFR vsby in fog persists. Otherwise
VFR to start from KROA eastward including mainly clear skies at
KLYH/KDAN early on. As a weak upper level disturbance passes to
the southeast this morning, expecting some decrease/lifting of
sub-VFR cigs over the mountains although may take until mid
afternoon for KBLF to return to VFR and that remains uncertain.
Elsewhere appears that will see mainly VFR this afternoon with
little cloudiness across the east and slowly fading strato-cu
over the mountain locations.
Northwest winds will also remain gusty through much of the day
behind the departing upper system with gusts to 25 kts possible
along the Blue Ridge including KROA.
High pressure builds in overnight while some low level upslope
moisture may get trapped under warming aloft resulting in
periods of sub-VFR cigs espcly around KBLF overnight. May also
see some late night patchy fog develop with MVFR or briefly
worse at KLWB/KBCB and perhaps KBLF late. Otherwise expecting
clear skies under light winds making for overall VFR elsewhere.
Extended Aviation Discussion...
High pressure should bring VFR Monday into Tuesday. MVFR rain
showers are possible Tuesday night into Wednesday with the next
weak cool front entering the region midweek. High pressure
should strengthen by Thursday with a return to widespread VFR
expected toward the end of the week.
As of 307 PM EST Saturday...
Record High Temperatures and Year of Occurrence
Blacksburg, VA..65 in 1994
Bluefield, WV...66 in 1994
Danville, VA....73 in 1981
Lynchburg, VA...76 in 1939
Roanoke, VA.....77 in 1939
Blacksburg, VA..68 in 1984
Bluefield, WV...67 in 1986
Danville, VA....74 in 1971
Lynchburg, VA...76 in 1930
Roanoke, VA.....75 in 1939