Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 09/25/19

Area Forecast Discussion

National Weather Service Blacksburg VA

 731 PM EDT Tue Sep 24 2019

.SYNOPSIS...
Except for a chance of showers west of the Blue Ridge with a
weak front on Thursday, expect warm and dry conditions to
persist across the Appalachians and central mid Atlantic region
for the rest of the week.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 245 PM EDT Tuesday...

High pressure at the surface with some shallow ridging aloft
will keep fair weather across the Appalachians and central mid
Atlantic region through Wednesday. Satellite imagery shows a
good amount of cirrus blowoff streaming in our direction from
convection in the lower Mississippi valley but do not expect
that will hinder radiational cooling much overnight. This will
allow some valley fog to develop west of the Blue Ridge
overnight and put a good chill in the air by daybreak.
Conditions remain quiet on Wednesday with temperatures remaining
well above normal.

Lows tonight will be in the low to mid 50s east of the Blue
Ridge, but dip into the upper 40s/lower 50s to the west with
cooler readings in the valleys. Highs Wednesday will range from
the middle 80s east to upper 70s/lower 80s west.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 330 PM EDT Tuesday...

High pressure should head offshore during Wednesday night, and a
weak cold front will pass overhead on Thursday. The models
continue to agree that moisture will remain limited along the
frontal boundary. Any hope for measurable rainfall will reside
in southeast West Virginia and far southwest Virginia.
Confidence remains very low that any of this moisture will
survive east of the Interstate 81 corridor. Downsloping west
winds will create another hot day across the Piedmont with highs
testing the lower 90s again. By Thursday night, high pressure
should return to provide dry weather for Friday. Temperatures
will be a tad cooler on Friday but should still remain notably
above normal.

While model agreement remains excellent for Wednesday night
through Friday, that agreement begins to deteriorate on Friday
night. Model solutions diverge regarding the details of a
backdoor cold front approaching the CWA from the northeast as
high pressure begins to track southwestward from the New
England states. The GFS advertises a few showers developing
along this boundary, but other models such as the Canadian and
the ECMWF show the boundary being devoid of moisture. For now,
the forecast for Friday night will remain dry unless future
model runs trend anywhere closer to the GFS. Confidence is
higher that the GFS will probably lean drier in future runs
given its recent track record.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 330 PM EDT Tuesday...

An anomalously large 594 dam upper level ridge will build over
the southern Mississippi River Valley this weekend and into
early next week, while surface high pressure over Cape Cod heads
southwestward toward the Mid Atlantic. Meanwhile, an
aforementioned backdoor cold front ahead of this high pressure
area will pass over the CWA. The GFS appears bullish in firing
a fairly wide area of convection each afternoon along this
frontal boundary. Other models such as the Canadian and the
ECMWF suggest a stray shower or thunderstorm may develop each
afternoon, but they paint a much drier picture overall. Anything
that does form would likely lack organization due to no
meaningful wind shear or steering currents aloft.

Given the ongoing dry spell, it seems more prudent to stay on
the drier side of the model solutions by maintaining just
slight chance POPs along this passing frontal boundary during
Saturday through Monday. As high pressure retrogrades westward
toward the Appalachian Mountains by Tuesday, the chances of any
convection will diminish further as the atmosphere increasingly
becomes more capped aloft. Anyone looking for significant
rainfall that could put a meaningful end to this recent dry
period will more than likely have to wait beyond the timeframe
of this forecast. Concerns about drought and fire weather are
increasing across the Mid Atlantic and will continue to be
monitored during the upcoming days.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 731 PM EDT Tuesday...

High pressure will control our weather tonight into Wednesday.
VFR conditions will continue this evening into tonight. Areas of
fog will develop late tonight into Wednesday morning west of
the Blue Ridge mountains. IFR/LIFR valley fog is possible at KLWB
and possibly MVFR conditions at KBCB. Morning low clouds and
fog will lift quickly by late morning return all taf sites to
VFR conditions.

Winds will be light with no significant impact to aircraft
operations.

High confidence in ceilings, visibilities and winds during taf
period.

.Extended Aviation Discussion...

Mainly VFR conditions expected to continue at all terminal
forecast locations. High pressure will dominate the region
through the period - with exception of a break on Thursday as
a weak cool front passes through the area.

Only significant possibility for any type of flight restriction
might come from isolated late night/early morning fog in some
of the deeper mountain valleys, and perhaps also for a brief
period of lower upsloping clouds across the western flanks of
the Appalachians following the cool front on Thursday night.
Dry weather is expected on Friday. Isolated MVFR shower or
thunderstorm is possible on Saturday in the west. An isolated
thunderstorm may develop on Sunday.

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

&&

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

&&

$$
SYNOPSIS...MBS
NEAR TERM...MBS
SHORT TERM...PW
LONG TERM...PW
AVIATION...KK/MBS