-- Discussion containing changed information from previous version are highlighted. --
911
FXUS61 KRNK 230018
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
818 PM EDT Wed May 22 2024

.SYNOPSIS...
Isolated thunderstorms are expected again this afternoon as the
region remains between high pressure over the western Atlantic and
low pressure in the central United States. This low crosses the
Great Lakes and will drape a front across the Ohio and
Tennessee Valleys by Thursday bringing showers and
thunderstorms, along with a chance of heavy rain to the region
Thursday and Friday. The wet weather pattern continues through
the beginning of next week with yet another front crossing
through the area.

&&

.NEAR TERM /THROUGH THURSDAY/...
-- Changed Discussion --
As of 800 PM EDT Wednesday...

Radar indicates that the strong storms from earlier this
evening have fizzled, with only residual showers remaining
across the mountains. However, keeping an eye on the complex of
rain and embedded thunderstorms over Kentucky and Tennessee that
is gradually moving east. Rapid update models indicates this
rain will enter areas west of Interstate 77 before midnight,
but this activity will then weaken in the downslope windflow
through 4 am. Otherwise, will be watching for renewed showers
and storms moving across the lower Mid-Atlantic on Thursday
afternoon, which weather forecast models have been consistent in
indicating over the past several hours. Latest forecast update
reflect rain entering from the west late this evening, as well
as adjustments to temperatures and cloud cover through the
night.


As of 200 PM EDT Wednesday...

Key messages:

   - No significant changes to probability of precipitation
   - Confidence high for above normal temperatures
   - More showers and storms accompany a front on Thursday

Above normal temperatures today in the upper 70s and 80s for the
entire forecast area due to abundant sunshine earlier this
morning and only partly cloudy cumulus and stratocumulus this
afternoon. Southwest flow is also enhancing temperatures and
moistening the atmosphere. There is little to no upper
atmosphere support for convection, and a front coming from the
plains is still too far west to meaningfully increase our storm
potential. Thus, most convection today will be anchored to
ridges and mountains as topography will drive most convective
initiation. Some areas will reach their convective temperature,
but without any support, severe potential is limited. So
isolated storms will pepper the area, concentrated along the
Blue Ridge and just west. A few small singular cells are forming
in the southern Blue Ridge. Once we lose diurnal heating, expect
convection to die quickly after dusk.

A cold front will drape itself through the TN/OH Valleys and
sink south into the Mid-Atlantic on Thursday. Because of this,
expecting Thursday to be more active and have more widespread
convective coverage than today. High resolution models aren`t in
excellent agreement on the areas of highest threat, but higher
CAPEs and instability sit south of the VA/NC state line.
Damaging winds would be the greatest threat with any strong to
severe storms that form Thursday. Temperatures will be similarly
warm in the 70s and 80s.

Antecedent conditions have primed some areas in the mountains
for future flooding threats. With a slow moving frontal boundary
positioned for a collision with healthy moisture and PWATs
around and in excess of 1.5", localized flooding is a threat
each afternoon.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 130 PM EDT Wednesday...

Key Messages:

1. Daily chances of showers and thunderstorms through the period.
2. Locally heavy rain possible, may result in localized flooding.
3. Above normal temperatures through the period.

A cold front will reach the area by Thursday, and eventually stall
over the eastern US by the end of the work week. Showers and
thunderstorms as a result of this front will be ongoing by the start
of this forecast period, lingering into the overnight and
through Friday with plentiful ambient moisture and the nearby front.

Shower and thunderstorm chances continue through Friday as another
mid level shortwave moves into the Mid Atlantic, with the greatest
chances during the peak afternoon heating, but decrease overnight.
Saturday looks to start off dry, but a mid level trough crosses
later in the day to bring increased potential showers and storms.
Deep layer shear is also forecast to be higher on Saturday, compared
to Friday, which would support more organized storms, especially if
the passage of the upper trough coincides with peak diurnal heating.

Generally southerly flow will continue to advect moist air into
the region, keeping precipitable water values above normal
through the forecast period. That being said, rain showers may
be heavy at times through the end of the work week and into the
weekend. Soil moisture over the area is already fairly high from
recent rainfall, and these additional rounds of rain,
especially if over the same areas, could increase risk of
localized flooding.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 200 PM EDT Wednesday...

Key Messages:

1. Daily chances for showers and storms continue into the work week.
2. Temperatures still above normal, but somewhat cooler by midweek.

For the Memorial Day weekend, ridging aloft between system will
bring a brief respite from the rain Sunday morning, although
confidence is low on how long that break will be. Another cold front
approaches from the west, associated with a deeper 500mb trough. A
prefrontal trough may reach the area late Sunday, which may increase
chances for showers and storms later in the day for the western
mountains. The front looks to reach the central Appalachians by
Monday, keeping showers and thunderstorms in the forecast for
Memorial Day. Potential for severe storms at this time looks to be
higher Monday, given the better upper level support via the upper
trough. However, at this time, it is still too far out to determine
mesoscale details that influence severe weather potential. The cold
front looks to cross the area Tuesday, bringing a cooler and drier
airmass to the region, and with this change in airmass, expecting
cooler temperatures for the middle of the work week.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
As of 815 PM EDT Wednesday...

Showers and storms have diminished for the time being, but will
be keeping an eye on the activity that will impact BLF and LWB,
possibly BCB during the 23/04Z to 08Z timeframe with mainly rain
that may reduce visibilities. May be some embedded thunder with
this activity, but expect this activity to weaken in the
downsloping flow.

Given debris clouds overnight, believe fog development will be
localized, mainly where skies clear. Ceilings should remain VFR,
though patches of MVFR ceilings may develop.

A cold front will enter the area on Thursday, bringing a likely
chances for thunderstorms during the 19Z to 23Z timeframe. Along
with the frontal passage, reduced visibilities in heavy rain, as
well as sub-VFR ceilings are possible.

Prevailing winds are light from the west or southwest through
this forecast period.

EXTENDED AVIATION OUTLOOK...

Waves of low pressure riding along a front stalled nearby the
region will trigger rounds of showers and thunderstorms, and
increase the likelihood of MVFR conditions Friday through
Sunday.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...AMS
NEAR TERM...NF/VFJ
SHORT TERM...AS
LONG TERM...AS
AVIATION...AMS/NF/VFJ