223
FXUS61 KRNK 242330
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
730 PM EDT Mon Jun 24 2024

.SYNOPSIS...
High pressure and a less humid air mass over the Ohio Valley
will be centered over the central Appalachians by Tuesday morning. A
cold front crossing the region on Wednesday will bring a return of
showers and thunderstorms, especially in the afternoon and evening.
Thursday and Friday are expected to be warmer and more humid with
a low probability of any precipitation.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 655 PM EDT Monday...

No major changes are expected to the ongoing forecast.
Currently, winds are still around 10 to 15 mph for much of the
region along with some gusts near 15 to 20 mph. Around and just
after sunset, these winds will trend to values around 5 to 8 mph
and weaker. The cumulus clouds will also dissipate leaving a
mostly clear to clear night across the region. Have tweaked
hourly temperatures, dew points, wind speed/gusts, and sky
cover to better reflect the latest conditions and expected
trends through the late evening.

As of 215 PM EDT Monday...

Key messages:

     - Dry and less humid

Surface dew points were already dropping behind the cold front
that was pushing through southeast Virginia and eastern North
Carolina. Cloud cover will erode after sunset and wind speeds
will also diminish. Despite the drier air, the cooler
temperatures over the warmer water of area rivers and lakes
will result in shallow fog Tuesday morning. Little cloud cover
is expected Tuesday and a large rise in temperatures will bring
highs into the lower 80s to lower 90s.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 130 PM EDT Monday...

Key Messages:

1. Hot and more humid by Wednesday.
2. Showers and thunderstorms Wednesday into Thursday.

Nearly zonal flow aloft Tuesday night turns more southwesterly, as
another trough digs into the Tennessee and Ohio Valleys, while a
cold front approaches the central Appalachians from the west. Though
surface high pressure will keep the weather quiet through the
beginning of Wednesday, southwesterly flow ahead of the cold front
brings in additional moisture and warmer temperatures, so a return
to hot and more humid conditions Wednesday. Instability will
increase over the area with diurnal heating, increasing potential
for showers and thunderstorms as the front nears the area. Though
timing details are still uncertain at this time, some guidance is
suggesting prefrontal storms to develop over the Piedmont by early
to mid afternoon, and then another round of storms attendant to the
frontal passage in the west by the evening, as said in the forecast
discussion from the previous shift. There is a marginal risk for
severe thunderstorms, damaging winds being the greatest threat, and
possibly heavy rain, given precipitable water values near the 90th
percentile relative to climatology. However, the better upper
dynamics look to stay farther north, closer to the upper trough.
Similar to the frontal passage this past weekend, the showers and
storms with the front may not make it over the Blue Ridge Wednesday
night, also noted in the previous forecast discussion, as
instability decreases through the night.

High pressure builds back in over the region behind the front by
Thursday, sliding across the northeastern US, which will keep the
weather quiet for most into the end of the week. However, east to
northeasterly flow around the high could bring some moisture into
the area from the Atlantic, and the front lingers across the
Carolina coast, so may see some showers and storms develop over that
area Thursday afternoon.

Temperatures Wednesday will be the hottest of the forecast period,
in the mid to upper 80s in the west, and mid to upper 90s in the
east. The increased humidity will bump heat indices back into the
upper 90s to near 100 in the Piedmont, though cloud cover and rain
could impact high temperatures. Thursday will be several degrees
cooler than Wednesday, closer to seasonal normals, behind the front.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 130 PM EDT Monday...

Key Messages:

1. Hot temperatures Friday and into the weekend.
2. Increasing probability for showers and storms Sunday.

High pressure will trek across the northeastern US Friday and into
the weekend, and ridging at 500mb builds over the southeast states.
With heights increasing over the Mid Atlantic once again,
temperatures will climb back to the mid to upper 90s in the east,
and mid 80s in the west, though the higher elevations will remain a
few degrees cooler. As the high continues to shift further east,
return flow from the Atlantic will advect moisture into the area,
and increasing surface based instability from diurnal heating will
increase chances for afternoon showers and thunderstorms developing
across the mountains Friday and Saturday. The next cold front
approaches from the west by the weekend, and looks to cross the area
Sunday. With better forcing via the front, and upper level support
as mid level trough crosses the Great Lakes into the Northeast,
there is higher probability for more greater coverage of showers and
storms Sunday afternoon into the evening. Moderate to heavy rain
looks possible with these storms, as forecast precipitable water
values near the 99th percentile relative to climatology. High
pressure builds back in over the region for Monday behind the front,
bringing a return to mostly dry weather.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 725 PM EDT Monday...

VFR conditions are expected through the vast majority of the
valid TAF period concluding at 00Z Wed/8pm EDT Tuesday. The
exception will be some late night/early morning fog within
mainly the mountains river valleys. Northwest to north winds
around 10kts with gusts 15 to 20 kts will weaken fairly rapidly
after sunset and either be sustained around 5 to 7kts or become
light and variable through the night and into Tuesday.

Confidence in the above aviation forecast scenario is high.

EXTENDED AVIATION OUTLOOK...

VFR conditions expected through much of the week, with the only
exception being areas of valley fog in the early morning hours,
and with any storms Wed.

The chance of showers and thunderstorms will be confined to the
southern Blue Ridge and foothills on Thursday and Friday.

Isolated afternoon and evening thunderstorms.are possible
anywhere across the region on Saturday due to a hot and
unstable airmass.

&&

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

&&

$$

SYNOPSIS...AMS
NEAR TERM...AMS/DS
SHORT TERM...AS
LONG TERM...AS
AVIATION...AMS/DS