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FXUS61 KRNK 190416

Area Forecast Discussion
National Weather Service Blacksburg VA
1116 PM EST Thu Jan 18 2018

High pressure shifts from the Gulf Coast states tonight to the 
southeast coast by Saturday. This high pressure system will then
linger over the southeast states into Monday before a cold 
front enters from the west Monday night into Tuesday.


As of 900 PM EST Thursday...

Low temperatures the main concern overnight as winds remain
gusty on the ridges while have decoupled in spots across the
valleys and out east. This continues to make for a wide range in
values from the mid teens in spots to the mid 30s at elevation.
Evening soundings show a 35-40 kt westerly 85h jet that continues
to mix down given such dry air and a very low inversion. Models
show this jet slowly weakening overnight as the high to the
south slips east but enough with possible waves breaking to keep
speeds up past midnight. This should also hold lows in the 20s
along the ridges overnight with some teens elsewhere, as would
only take a short period of lighter winds over snow cover and
low dewpoints for readings to plummet. Therefore only making
small changes to the earlier update of gridded temperatures with
the ongoing advisory/sps for black ice continuing into Friday.

Previous discussion as of 210 PM EST Thursday...

Winter weather advisory for refreeze of snowmelt in NC through 
Friday morning, per policy agreement with NC EM officials. Rest of 
CWA will likely be under a Special Weather Statement to cover 

Otherwise, looking at high pressure building in with winds subsiding 
this evening but not quite going calm. Still a chilly night with 
lows in the teens, but at least wind chills will not be as low given 
less wind. One possible concern tonight besides the slick roads 
would be fog. With warm advection and somewhat lighter winds over 
snow, fog can sometimes form. However, given limited melting the low 
levels stay a little dry and winds may stay up enough overall to 
restrict fog formation, but still possible, especially in the 

We continue to stay in a split flow pattern into Friday with heights 
rising and 8h temps rising per warm advection. Under sunny skies, 
temperatures should reach into the 40s. We should start to see 
better snowmelt Friday.


As of 115 PM EST Thursday...

This period of the forecast will be highlighted by a warming trend 
across the area. An upper level ridge will build across the 
southeast U.S., all while the synoptic flow across our region turns 
zonal. By the end of this time period, low level trajectories that 
clip far western parts of the area will have their origin from 
across the western Gulf of Mexico. The result will be moderating 
temperatures with eventually increasing clouds by the end of the 
weekend, especially across the west, with also the potential for 
some isolated showers across the far west by Sunday. By Sunday, high 
temperatures will range from the low to mid 50s across the 
mountains, and mid 50s to around 60 across the Piedmont.


As of 130 PM EST Thursday...

The mild weather will continue Sunday night into Monday in advance 
of an approaching cold front. Also, isolated to scattered showers 
will start to increase across the area during the day in advance of 
this same front. Look for showers to become more numerous Monday 
night into early Tuesday morning as the front passes through the 
region. While temperatures will decrease behind the front, readings 
will still remain above normal for this time of year heading through 
the middle part of the week.

After Monday night, our next chance for precipitation will be a 
small one Wednesday night into Thursday as a weak disturbance passes 
through FL/GA/SC. Otherwise, dry weather is expected as another area 
of high pressure builds into the region.


As of 1115 PM EST Thursday...

VFR to prevail under clear skies through the period. West-
northwest winds will continue to slowly diminish across the
ridges overnight although could still see gusts in the 20-25
knot range into pre dawn hours of Friday along the higher peaks.
These lingering stronger winds above the near surface inversion
may result in low level wind shear in spots across the western
sites for a few hours overnight as surface winds diminish.

As the surface high to the south slides east should see lighter
westerly winds on Friday with speeds generally 10 kts or less
with perhaps a few gusts to 15-20 kts along the ridges during 
the afternoon.

Extended Discussion...

High pressure will cover the region Saturday through Sunday. 
VFR conditions are expected as well as warming temperatures. 
Moisture will return to the west Sunday night into Monday night
with sub- VFR conditions possible in low clouds and rain 
showers ahead of another cold front. VFR conditions return 
during Tuesday as weak high pressure follows the front in from 
the west.


As of 245 PM EST Thursday... 

NOAA Weather Radio, WXL60 (Roanoke Transmitter) which broadcasts at 
162.475 MHz remains off the air. The phone company continues to
investigate and no estimated time has been given for restoring
this. We apologize for the outage.


NC...Winter Weather Advisory until noon EST Friday for NCZ001>006-



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