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-- Discussion containing changed information from previous version are highlighted. --
963
FXUS61 KRNK 270113
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
913 PM EDT Mon Jun 26 2017

.SYNOPSIS...
-- Changed Discussion --
Weak high pressure over the region tonight will give way to a
fast moving upper level disturbance that should cross the area
from the northwest on Tuesday. Other than some isolated to
scattered showers and storms in association with this feature on
Tuesday, high pressure will provide for dry and cool weather
for much of this week. The chance for more abundant showers and
storms, as well as increasing temperatures, return Friday into
the weekend.
-- End Changed Discussion --
&&

.NEAR TERM /THROUGH TUESDAY/...
-- Changed Discussion --
As of 900 PM EDT Monday...

Some return of moisture slowly occurring across the region this
evening as seen via the latest blended TPW and PWATS off soundings
just south of the area. This in advance of a fast moving upper
disturbance seen across the Midwest this evening per latest
water vapor loop. Some of this moisture from spreading out of
afternoon cumulus remains stuck under the inversion aloft this
evening with even a few sprinkles showing up across the far
western I-81 corridor. Although not expecting too much eastward
progression of any light showers, will include a shower or
sprinkle mention for an hour or two to start late this evening.

Otherwise main inbound axis of deeper moisture likely to fade
upon arrival into the drier air aloft after loss of heating late
tonight as evidenced by latest drier solutions. However likely
best to keep some low end pops going late tonight as the NCAR
Cam ensemble showers some light showers far west late and
perhaps jumping the Blue Ridge early in the morning. Otherwise
beefing up clouds over the west and central overnight with
partly cloudy to clear elsewhere. Also bumped up lows a little
given slightly higher dewpoints southeast, and earlier arrival
of strato-cu over parts of the mountains, but still mainly 50s
overall by daybreak.

Previous discussion as of 230 PM EDT Monday...

Daytime cumulus clouds should give way to mostly clear to clear
skies this evening. However, the approach of an upper level
disturbance will start to bring a return of cloud cover to the
area after midnight tonight, and conditions will remain mostly
cloudy to cloudy through the day on Tuesday.

Isolated showers may reach the far western sections of the area by
late tonight, but chances will increase during the day Tuesday. The
best potential for showers and storms will extend from roughly
Lewisburg, WV to Bluefield, WV to Marion, VA to Boone, NC. East of
this region, precipitation in the form of isolated showers will be
more likely, east to roughly a Lynchburg, VA to Reidsville, NC line
during the afternoon.

Temperatures will continue to be on the cool side for this time of
year. Lows tonight will range from the upper 40s to the lower 50s
across the mountains and the mid to upper 50s across the Piedmont.
High temperatures on Tuesday will range from around 70 to the lower
70s across the mountains to the mid to upper 70s across the Piedmont.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 240 PM EDT Monday...

At 00z Wednesday (8 pm EDT Tuesday)...the axis of an upper level
trof will be exiting our forecast area and any lingering mountain
showers will have ended. With a large area of high pressure settling
over the region...morning lows Wednesday will be well below normal
and went a few degrees below guidance. The COOP MOS guidance is
forecasting lows in the upper 30s at Burkes Garden.

High pressure continues to influence our weather on Wednesday. With
limited mixing...leaned toward the cooler guidance for highs which
should range form the lower 70s in the mountains of NW NC to the
lower 80s in the NC/VA Piedmonts.

The transition to higher humidity levels and warmer temperatures
begins Wednesday night into Thursday as higher low level theta-e air
lifts north into the region as a deepening west/southwest flow
arrives. Most the area will remain dry on Thursday, but a few
showers cannot be ruled out in the southern Blue Ridge of NW NC and
far southwest VA on the nose of a low level theta-e ridge,
increasing PWATs and differiental mountain heating. With
downsloping winds, pushed high temps Thursday up a degree or two
from the previous forecast.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 200 PM EDT Monday...

A return to weather conditions more typical for summer are expected
during the long term period, as the long range models show good
agreement transitioning from an upper level zonal flow early in the
period to an upper trof forming somewhere around the Great Lakes and
extending south into the eastern U.S. by late in the weekend into
Monday.

This will result in increasing temperatures and humidity, as well as
an increase in storm chances. An upper level disturbance moving out
of the western Gulf of Mexico into eastern VA on Friday/Friday night
will help lead a surge in higher PWAT air our area. This higher
moisture combined with a series of upper level disturbances...with
the usual differences in timing shown in the long range
models...will help generate scattered showers and storms each day
during the long term period, especially during the peak heating in
the afternoon and early evening hours. With increasing CAPES, but
low shear through the period,a few pulse severe storms and locally
heavy rain are possible.

Warmest temperatures are expected Sunday and Monday as 850mb
forecast temps approach +20C. This may generate heat index values in
the low to mid 90s in the east.

&&

.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
As of 750 PM EDT Monday...

Expecting generally VFR conditions at TAF sites through the
period. Fog formation was quite limited last night, and after
another day of excellent drying expect increasing mid/high
clouds to prevent any sub VFR conditions due to fog/stratus
through daybreak. Approaching upper trof will help push a cold
front through the area tomorrow, but deep moisture is absent
and instability is also limited. Expect the end result to be a
VFR cig with isolated showers and possibly a rumble of thunder
mainly west of the Blue Ridge. With coverage expected to be so
sparse will leave any mention of VCTS out TAFs. BufKit soundings
tomorrow show a very well mixed and deep boundary layer so
believe some low end gusts in the 15KT to 20KT range will
materialize during the afternoon.

Extended Aviation Discussion...

Isolated IFR/MVFR fog late Tuesday night/early Wednesday
morning in areas that received rain during the day Tuesday.
High pressure will then keep the bulk of the area VFR through
Thursday.

Friday into Saturday, the potential for sub-VFR conditions
increase as showers and storms become more numerous. Likewise,
an increase in the boundary layer moisture will also lend itself
to better chances of late night/early morning patchy fog.

&&

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

&&

$$
SYNOPSIS...DS/JH
NEAR TERM...DS/JH
SHORT TERM...PH
LONG TERM...PH
AVIATION...DS/MBS