Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 09/08/20

Area Forecast Discussion

National Weather Service Blacksburg VA

 942 PM EDT Mon Sep 7 2020

.SYNOPSIS...
High pressure will continue to bring quiet weather to the
Appalachians and central mid Atlantic region through tonight. A
very strong cold front will extend from the New England to the
southwest United States Tuesday before low pressure develops
along the front over the Southern Plains and tracks into the
Ohio Valley by the end of the week. There will be an increasing
chance of showers and thunderstorms across the area Wednesday
and Thursday ahead of this front.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 942 PM EDT Monday...

Cool and comfy conditions remain in place areawide. Temperatures are
already in the mid to upper 50s over the higher terrain with low to
mid 60s elsewhere. Roanoke and Lynchburg are the warmest with
readings close to 70 degrees. A tad bit more humidity can be noted
especially in areas east of the Blue Ridge.

Further to the north the line of showers and storms that has plagued
Cleveland, Ohio and western sections of Pennsylvania continues to
die out as it sags south into drier. Meanwhile moisture is slowly
slagging up from our south across South Carolina and Georgia. Hi res
models showing a later arrival on this moisture Tuesday especially
in areas across the Southside and Piedmont. Even with that said
still looking a some isolated to widely scattered light showers
pivoting in for the afternoon and evening hours. Low clouds will
also be noted in areas east of the Blue Ridge come Tuesday afternoon
as the wedge continues to build and easterly flow strengthens.


As of 555 PM EDT Monday...

Beautiful, gorgeous, pleasant, and superb are just some of the words
that describe our weather this Labor Day evening. High pressure
remains entrenched just to our south over the southern Appalachians
making for another fairly comfortable night ahead. Lows will be back
in the mid to upper 50s west of the Blue Ridge with upper 50s and
low 60s out east. Some of our usual valley locations such as Burkes
Garden look to fall back into the mid to upper 40s to around 50
degrees. Valley fog will also be possible west of the Blue Ridge.

One thing that is different this evening compared to what we had
over the Labor Day weekend is a slight increase in humidity. As our
high starts to weaken overnight our wedge will be allowed to build
bringing in more moisture off the Atlantic. This moisture will usher
in some low clouds and patchy fog early Tuesday morning across the
Southside and Piedmont. These clouds will eventually spread further
east according to hi-res solutions by Tuesday mid afternoon. The
clouds will be followed up with isolated to widely scattered storm
chances out over the Piedmont and Southside as the easterly flow
starts builds more moisture in. For now left 20-30 percent
precipitation chances over this area. Highs Tuesday will be in the
low to mid 80s areawide with the exception of a few mid to upper 70s
out over the higher terrain.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 200 PM EDT Monday...

Easterly flow from earlier in the week will ensure plenty of
moisture is in the area for the midweek. Wednesday will have
scattered diurnal showers and storms in the afternoon. Most of the
CWA ought to receive measurable rainfall on Wednesday, but the
probability is low that it will be heavy enough to create any hydro
concerns.

Thursday afternoon and evening will see greater coverage and chances
than Wednesday ahead of a cold front approaching from the west.
Overnight into Friday expect showers to linger as the front itself
passes over us. But much like the rest of the week before it,
diurnal afternoon showers will reappear on Friday. These will be
helped along by another wedge that begins to take shape along the
eastern Appalachians as high pressure sits over New England.

Temperatures for this period will be oscillating around normal, with
daily highs in the 70s and mid 80s, and overnight lows in the 60s.

&&

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

A trough and surface low track over the Great Lakes/southern Canada
through the weekend. Guidance is split over the exact order of
events, with some bringing a frontal boundary from south to North,
and occluding with the cold front that drags down from Canada. This
would clear out the wedge that began to form on Friday. Others leave
the wedge in place and allow the cold front to be the feature to
clear the wedge. despite the uncertainty in features and timing over
the weekend, the most likely scenario is more diurnally forced
showers and storms through this period.

Despite an expected cold frontal passage, the temperature gradient
between the two air masses is not particularly strong, so a
significant cool down is not expected in this period. Temperatures
will go from the 60s at night to upper 70s/low 80s during the
day.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
As of 746 PM EDT Monday...

VFR conditions continue this evening at all of the TAF sites. Some
valley fog can be expected in areas west of the Blue Ridge with the
best confidence for IFR/LIFR conditions at KLWB. Some patchy
IFR/LIFR conditions expected further south toward KBCB but opted to
leave the tempo group in for now based upon how the fog situation
evolved from earlier this morning and the overall progression of
moisture from the east.

As of now it does not looks as if this moisture will reach
KROA, KBLF, KLWB, or KBCB until late Tuesday afternoon.KDAN and
KLYH on the other hand will start to see some of this moisture
in the form of mid to high level clouds by 12-14z Tuesday than
some low level clouds by 18z and beyond Tuesday afternoon. Also
opted VCSH at both KDAN and KLYH since they will sit closest to
the moisture source off to the east.

Winds will be light through the period with no impact to aircraft
operations expected.

.Extended Aviation Discussion...

Moisture returns for widespread diurnally driven showers and
scattered thunderstorms resulting in MVFR ceiling and visibility
Wednesday through Sunday.

&&

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

&&

$$
SYNOPSIS...MBS
NEAR TERM...ET/MBS
SHORT TERM...VFJ
LONG TERM...VFJ
AVIATION...ET/MBS