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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 050534
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
134 AM EDT Wed Aug 5 2020

.SYNOPSIS...
A weak cold front will cross the central Appalachians from the
northwest tonight, then stall and dissipate Wednesday. The
remainder of the week will feature building high pressure aloft
which will result in typical summertime weather favoring near
seasonal temperatures and scattered afternoon and evening
thunderstorms.

&&

.NEAR TERM /THROUGH TODAY/...
As of 120 AM EDT Wednesday...

A few showers remain across southside Va/NC piedmont along
theta-e ridge and low level convergence, though appears
weakening trend will persist to a point that we should be dry
after 4am. Fog will be around into the morning especially the
mountains of WV/far SW VA. Some mid level clouds will increase
into these areas to keep fog becoming widespread and dense.

Previous discussion from Tuesday evening...

Showers tracking to the east across the area are beginning to
fade as the sun sets. By midnight, the area should also see
clouds thinning which could lead to fog forming by sunrise
tomorrow. The best bet for fog would be in mountain valleys,
but could also see good coverage in the piedmont where ground
remain wet from Isaias.

As of 300 PM EDT Tuesday...

Scattered showers and a few thunderstorms are expected this
evening associated with a cold front that is crossing the
mountains from the northwest. This front is expected to stall
and then dissipate over the area Wednesday with renewed
shower/storm activity during the afternoon as instability
nourishes new convective cells. Convective allowing models
indicate a modest plume of CAPE to reside over the mountains
Wednesday afternoon, MLCAPE of 2000 j/kg with primary
convergence over the mountains during the early/mid afternoon
then translating downstream into the piedmont Wednesday evening.
Depending on how the storms cluster as they come off the
mountains may have to deal with a few strong to isolated severe
cells during the peak heating of the late afternoon and evening.

Temperatures tonight and Wednesday reflect the seasonal norm
with lows dipping into the upper 50s to lower 60s west, to the
mid/upper 60s east...and highs 70s west to the mid/upper 80s
east.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
As of 300 PM EDT Tuesday...

A dome of high pressure will sit over the Ohio Valley for most of
this period, and slowly spread so there is broad surface high
pressure over much of the eastern CONUS by the weekend. A weak front
in our area will drift slowly east through the end of the week,
providing some forcing in addition to orography to spark scattered
storms each afternoon. When an upper trough passes by on Friday it
will help usher the front off the coast and make room for the
aforementioned high pressure.

Highs will be in the 80s each afternoon east of the Blue Ridge, high
70s west. Nights will be nice and cool thanks to the high pressure
helping suppress cloud coverage and allowing radiative cooling after
sunset.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 300 PM EDT Tuesday...

The large scale pattern over the CONUS won`t be pushing the envelope
this period, as we sit in a pretty standard summer setup through at
least Tuesday. A Bermuda high will be in place over the southern
Atlantic, spreading weak high pressure over most of the East Coast.
This humdrum pattern also means there are no significant atmospheric
features around which storms could fire up consistently. Thus, this
period will be characterized by hot summer afternoons pockmarked by
scattered to isolated diurnal thunderstorms.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 125 AM EDT Wednesday...

Expect mainly VFR this morning with exception of the mountains
where fog and stratus appears to be setting up. Although some
mid deck may bring variability in this, where vsbys drop to a
mile or less, but then rise back up to 4-6sm, so overall leaning
toward pessimistic per latest sat trends with lower vsbys.

Any fog and stratus lifts toward 12-14z, with scattered/broken
cumulus forming late in the morning into the afternoon with
storms expected along a frontal boundary. Some of the storms
will bring heavy downpours but overall coverage will be
scattered. For now have VCTS at all sites except LWB where drier
air will move in behind the front to limit coverage, though
confidence is average on this.

Storms could linger east of the mountains through the end of the
taf period but overall will leave out VCTS past 00z.

Extended Aviation Discussion...

Typical summertime weather pattern expected through the weekend
with scattered afternoon and evening thunderstorms and patchy
late night fog. Any flight restrictions are expected to be
temporary.

&&

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

&&

$$
SYNOPSIS...PM
NEAR TERM...PM/RCS/WP
SHORT TERM...VFJ
LONG TERM...VFJ
AVIATION...RCS/WP