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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 101404
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
1004 AM EDT Wed Apr 10 2024

.SYNOPSIS...
A weak disturbance and increased moisture will produce occasional
rain showers through this morning into early afternoon. A strong low
pressure system will bring the possibility of heavy rain, as well as
thunderstorms for Thursday. Some showers may linger into Friday,
mainly in the west and north, and closer to the track of the low as
it exits the region. Once the low departs, conditions should dry out
for the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
As of 955 AM EDT Wednesday...

The biggest adjustment to the forecast will be the timing of
showers crossing the region today, and a decrease in the overall
probability of measurable rainfall. The latest radar imagery
depicts a cluster of showers primarily in our North Carolina
counties, with the majority of this activity east of I-77. Very
little precipitation was noted north of the VA/NC border other
than perhaps some very patchy light rain or sprinkles. The weak
disturbance responsible for the showers will cross the area
today, but the latest trends of the CAMs suggest very limited
coverage across the northern half the region into the early
afternoon, with the southern sections seeing decreasing
coverage. By the mid to late afternoon, only minimal coverage is
anticipated across the north. Have adjusted the forecast
accordingly.

Have also tweaked hourly temperatures, dew points, and sky
cover to better reflect the latest conditions and expected
trends heading into the early afternoon.


As of 330 AM EDT Wednesday...


Key Messages:

1. Chance for showers this morning into early afternoon.

2. Approaching strong low pressure system tonight.

We remain in an axis of enhanced deep layer moisture today and
another area of isentropic upglide along with a weak upper
impulse should allow for some isolated to scattered shower
development. The greatest chance for development looks to be
this morning into early afternoon, then the moisture axis shifts
a bit more northward allowing for some slightly drier air to
nose in. It`s possible we may get to see a few breaks in the
persistent cloud cover later this afternoon into evening before
our focus shifts to the influence of a large deepening low to
the west that is progged to bring some increased gradient
southerly winds tonight and some potential for heavy rain
showers beginning to the SW CWA for Wednesday morning. There are
some strong dynamics with this system along with the
possibility for strong organized convection. See the short term
discussion below for more details.

Temps look to be above climo norms for highs today and overnight
lows decently above climo due to increased southerly advection.

Forecast confidence is medium to high.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 400 AM EDT Wednesday...

Key Messages:

1) Confidence is high for a cold front to bring gusty winds along
with showers and thunderstorms on Thursday.

2) A marginal risk of severe weather and/or flooding during
Thursday and Thursday night.

3) Gusty winds are likely after the frontal passage for Friday and
Friday night.

An intensifying low pressure system will move northeast through
the Ohio Valley Thursday, it`s associated cold front crossing
the Appalachians late Thursday, then off the east coast by
daybreak Friday. Pre-frontal showers with embedded thunderstorms
are expected Thursday morning, followed by a dry slot Thursday
afternoon with opportunity for additional showers/storms to
form along the front Thursday afternoon-evening.

South winds will increase ahead of the front with gusts up to
30 mph...especially across the higher elevations. Prefrontal
rain which falls Thursday morning may be heavy at times,
enhanced by the southerly winds along the Blue Ridge.
Thunderstorms which develop along the front Thursday afternoon
may also contain heavy downpours, but the activity Thursday
afternoon should move along quickly resulting in less residence
time with respect to rainfall. Of greater concern from the late
day storms will be the potential for severe weather...the
forecast hodographs for our region sufficiently curved to
promote storm cell rotation.

Not to dig into the weeds too much, but it appears our forecast
area will get dry slotted Thursday afternoon. The parent low is
forecast to lift northeast through the Ohio Valley, southwest
winds around the upper trough bisecting our forecast area during
the afternoon, introducing dry mid-level air. This will likely
bring the morning rains to an abrupt end early afternoon,
followed by some clearing and an opportunity for the boundary
layer to heat-up prior to the arrival of the cold front Thursday
evening. If this pans out as forecast then we will be dealing
with a supercell environment. Of course all of this is
conditional on the prefrontal activity exiting the region early
enough to build up some CAPE in the afternoon. The extensive
cloud cover could just as easily prevent the CAPE build-up,
leaving us with low topped showers and nothing to show for all
the directional shear. Attm, SPC has our entire forecast area
under a marginal risk for severe weather, with the greater
threats for severe targeted for the Ohio Valley (closer to the
parent low and upper diffluence). Overall consensus attm is the
threat will probably consist of sporadic damaging winds and a
few brief tornadoes within lower-topped convection, mainly from
mid-day through Thursday evening.

Once the cold front crosses the Mid Atlantic by Thursday night,
winds should shift towards the west and accelerate on Friday.
Gusts could reach up to advisory criteria (45-50 mph) along the
southern Blue Ridge with potential to down a few trees and
power lines...the standard windy scenario that we experience
with strong cold front passages. Temperatures behind the front
will retreat to normal values as cold air advection increases by
Friday night. Upslope rain showers should linger through Friday
and Friday night, and there is a chance that the rain could
change to snow along the higher elevations of western Greenbrier
County, WV, before the moisture dissipates. Attm not expecting
any accumulation.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 415 AM EDT Wednesday...

Key Messages:

1) Confidence is moderate for high pressure to bring drier weather
and lighter winds for Saturday.

2) A weak frontal boundary may provide a brief shower or storm
early next week.

High pressure will build across the Mid Atlantic region
Saturday, introducing dry weather. Winds will begin to diminish,
but may remain gusty at times through Saturday afternoon. As the
surface high moves to along the southeast Atlantic coast,
southwest return flow will bring increasing warmth to the region
starting Sunday with a notable temperature bump above normal
into next week. Meanwhile, a weak frontal boundary is forecast
to cross the Great Lakes and dive southeastward towards the
Appalachian Mountains. The boundary lacks any significant source
of lift or deep moisture, and it will run into drier air to the
south. Thus, the chance of showers/storms appears rather low
and mostly confined to the mountains.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
As of 640 AM EDT Wednesday...

Cigs should soon lower to mainly MVFR level this morning along
with -RA/-SHRA and some possible reduced VSBYs until about.
Cigs may improve a bit in the afternoon along with decreased
precip coverage, though some sites may stay MVFR. Initial winds
mainly SW near 5 kts or less, then increasing some today (under
10 kts) and becoming more south by afternoon. Increasing shower
chances later tonight with IFR/MVFR cigs along with increasing
SE winds.

OUTLOOK THURSDAY THROUGH SUNDAY...

Thursday: Restrictions expected due to lower CIGs/VSBYs in
SHRA/TSRA. Expect increasing S winds.

Friday and Saturday: Gusty W-NW winds expected. Upslope SHRA
continue into Saturday as storm system departs the region.
Restrictions will remain possible, especially W of the Blue Ridge.

Saturday night and Sunday: VFR flight categories expected.

&&

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

&&

$$

SYNOPSIS...AB
NEAR TERM...DS/AB
SHORT TERM...PM
LONG TERM...PM
AVIATION...BMG/AB