184
FXUS61 KRNK 131928
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
328 PM EDT Tue Aug 13 2024

.SYNOPSIS...
High pressure extends from the Great Lakes into the northern
Mid-Atlantic. This feature will keep our weather mainly dry
through Thursday. The next widespread chance for rain arrives
toward the end of the week and weekend as a low pressure system
approaches from the Ohio Valley.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 230 PM EDT Tuesday...

Key Message: Weather concerns the next 24 hours appear limited
to isolated showers and some late night fog.

High pressure is centered to our north with crux of the dry air
associated with this feature extending from the Great Lakes,
into the Ohio Valley and northern Mid Atlantic. Some moisture is
still present in the form of scattered cloud cover, but shower
activity is mainly confined to our south closer to a stationary
front over the deep south. Certainly can`t rule our a stray
shower or sprinkle across our forecast area but think the
subsidence from the high to our north will prevail during the
near term.

For tonight, mostly clear skies should promote good radiational
cooling. This should lead to patchy fog after midnight with
areas of river fog in the colder mountain valleys. Fog will then
dissipate by mid morning Wednesday with scattered cloud cover
for the afternoon in the form of cumulus.

Temperatures the next 24 hours are expected to remain slightly
below the seasonal normals for mid-August.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 245 PM EDT Tuesday...

Key Messages:

1). Wednesday and Thursday expect benign weather with just
isolated showers western mountains.

2). Friday brings better chance of showers and thunderstorms.

3). Temperatures remain near to below normal through the period.

Broad troughing aloft will remain over the eastern and central
U.S. north of 38 degrees latitude. Disturbances embedded within
this upper flow will drive the sensible weather through the
period for the forecast area. The first disturbance to track
across the region in the Wed-Thu time frame will have limited
available moisture and will be fighting a short wave ridge.
Thus, any precipitation with this first disturbance will be
largely limited to the mountains and areas west of I-77 with
just isolated to scattered showers and possibly a thunderstorm.

The upper trough will continue to suppress temperatures across
the area with a relatively minimum in temperatures parked over
the northeastern U.S. where 850mb temperatures hover around +15C
while elsewhere across much of the U.S., especially west of the
MS River 850mb temperatures are +20C and much higher. This will
equate to surface minimum temperatures mostly in the 50s to
lower 60s with high temperatures mainly in the 70s mountains to
lower and mid 80s elsewhere, which are near to slightly below
normal for mid-August.

Overall a benign weather period with no tropical threats for our
area and no heavy rain or severe weather threats either.

/Confidence Levels in Forecast Parameters/
- Moderate to High Confidence in Temperatures,
- Low to Moderate Confidence in Precipitation Probabilities,
- Moderate Confidence in Wind Direction and Speed,
- Low Confidence in Thunderstorm Potential.

&&

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

Key Messages:

1). Unsettled pattern evolving through the weekend with increasing
likelihood of showers/thunderstorms Friday into the Weekend

2). Temperatures remaining near to below normal through the
period.

As the first upper trough drifts east of the area troughing
redevelops across the Great Lakes and digs deeper into the OH
Valley and eventually slides east-southeast toward the Mid-
Atlantic region through the weekend. Cyclonic flow will develop
over the region resulting in a rather unsettled weather pattern
for the area. The trough will mean considerable cloud cover and
generally below normal temperatures as well.

The most significant chance for precipitation will arrive Friday
afternoon as an initial short wave and associated frontal system
drift into the region from the west. Look for a good chance of
showers and thunderstorms late Friday into Saturday. The threat
for severe/heavy rain does not look overly problematic at this
point, but that will need to be refined as we draw closer to
that period in time. Rainfall amounts with this first round
should average around 1/2 inch. As the upper low closes off and
drifts closer to our forecast area, cloud cover will remain
abundant and precipitation will trend toward more showery
activity with less thunder given less instability. At any rate,
the entire period will have a good chance of
showers/thunderstorms right through the weekend.

As noted above, temperatures will remain near to below normal
given the dominance of the upper low. Low temperatures will be
a bit milder than earlier in the week due to higher
dewpoints/humidity levels, but will still be mostly in the 60-65
range. High temperatures will top out mostly in the 70s west of
the Blue Ridge to the lower 80s east of the Blue Ridge.

/Confidence Levels in Forecast Parameters/
- Moderate Confidence in Temperatures,
- Moderate Confidence in Precipitation Probabilities,
- Moderate Confidence in Wind Direction and Speed,
- Moderate Confidence in Thunderstorm Potential.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
As 230 PM EDT Tuesday...

Mainly VFR expected through the 24 hour valid TAF. Exception is
the period from 06z/2AM-13Z/9AM Wednesday for IFR/LIFR vsby
restriction from fog. Models favor fog in the mountain valleys
but there is also concern for fog along and south of the VA/NC
border where rain has occurred.

Winds are expected to remain light and variable through
Wednesday.

Forecast confidence = average.



AVIATION OUTLOOK...

Mainly VFR expected Thursday.

An organized area of low pressure will approach the area by
Friday bringing the potential for precipitation and widespread
sub-VFR flight conditions which could last through Saturday.

&&

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

&&

$$

SYNOPSIS...PM
NEAR TERM...PM
SHORT TERM...RAB
LONG TERM...RAB
AVIATION...PM