517 
FXUS61 KRNK 291712
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
1212 PM EST Wed Nov 29 2017

.SYNOPSIS...
High pressure will bring fair weather and warm temperatures to 
the Appalachians and central mid Atlantic region through
Thursday. A cold front will then bring a chance of showers to
locations mainly west of the Blue Ridge Thursday night, followed
by a return to fair and warm conditions heading into the
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 905 AM EST Wednesday...

Very dry airmass remains in place. 12z soundings showing steep
but shallow inversion. Lack of clouds this morning will allow
temperatures to rise quickly once inversion breaks thanks to a
northwest flow in the low/mid levels. A few cirrus and stratocu
may shift toward the Alleghanys this afternoon. Have bumped
highs up another category in the foothills/piedmont, and just a
couple degrees in the mountains. Some piedmont locations may
reach the 70 degree mark, but no records appear to be in
jeopardy. Highs will range from the upper 50s to lower 60s
mountains, to mid 60s to near 70 east including the Roanoke
Valley.

Have also lowered dewpoints and rh this afternoon per northwest
flow and current dewpoints.

Previous discussion from early morning...

Generally fair and quiet weather for midweek. A weak cold front
will move into the region today and wash out with little impact
on our weather save for a few clouds. High pressure will then 
move into New England and wedge down east of the Appalachians 
tonight. Bufkit shows limited moisture in the boundary layer in
the wedge tonight so expecting a continuation of generally fair
conditions across the region. There may be a period from mid
morning into early afternoon where the wind may pick up a bit 
as higher momentum air associated with the weak front mixes out,
then a northeast breeze in the piedmont tonight as the wedge 
becomes established.

With little punch to the weak front today, expect temperatures 
to remain well above normal. Highs are expected to reach the 
middle 60s east of the Blue Ridge with upper 50s/lower 60s to 
the west.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
As of 300 AM EST Wednesday...

High pressure from New England to the southeast United States 
Thursday morning will gradually move offshore. Winds back around to 
the south then southwest ahead of the next approaching cold front. 

Deeper moisture with the front crosses southeast West Virginia, 
northwest North Carolina and southwest Virginia on Thursday night. 
Much drier air mass comes in behind the front with the clearing even 
in the western upslope areas by Friday afternoon. High pressure will 
be over the region Friday night. Low level moisture does not return 
around the west side of the high until late Saturday so have removed 
probability of precipitation for Friday night and Saturday. 

No significant changes to temperatures needed through the period. 
May lower minimum temperature in the sheltered valleys Friday night 
since the wind will decouple and become light and variable to calm. 
Along with a cleat sky, conditions will be favorable for rapid 
cooling during the evening.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
As of 118 PM EST Tuesday...

Models continue to advertise a fairly quick upper pattern with 
embedded shortwave ridges/troughs. First weak trough pushes east
by Saturday evening, and may see a few showers across the area 
Saturday with highs closer to normal in the lower to mid 50s.

Will see surface high build in Sunday across the Ohio 
Valley/Central Appalachians. Appears enough gradient such that 
winds could pick up from the northwest early. The high shifts 
east Monday while still influencing our weather with dry 
conditions with temps moderating a little. By Tuesday, warm 
front shifts north across the Ohio Valley with a small threat of
showers, mainly in the mountains.

&&

.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
As of 1210 PM EST Wednesday...

VFR through the period as high pressure moves across the area.
Winds will shift from the northwest to the northeast to
southeast through 18z Thursday.

Extended Discussion...

Thursday afternoon, a cold front approaching from the Ohio 
Valley and a weak low pressure system crossing the Tennessee 
Valley will increase clouds over the area. Some MVFR ceilings 
are likely in the mountains. By Thursday night, the probability 
of rain and MVFR ceilings is much higher over the mountains.

Winds will become gusty from the northwest behind the front 
Thursday night into Friday. VFR conditions should resume toward 
Friday night. High pressure and lighter winds will follow 
Saturday into Sunday with VFR.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.

&&

$$
SYNOPSIS...MBS
NEAR TERM...MBS/WP
SHORT TERM...AMS
LONG TERM...WP
AVIATION...MBS/WP