882
FXUS61 KRNK 091832
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
232 PM EDT Tue Jul 9 2024

.SYNOPSIS...
Low pressure merges with the remnants of tropical depression Beryl
over the Mid Mississippi Valley, then tracks into the Ohio
Valley. A cold front will push into the Mid Atlantic region on
Wednesday before becoming stationary through the end of the
week. As a result, showers and thunderstorms with locally heavy
rain remain in the forecast along with unseasonably warm
temperatures and humidity.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 200 PM EDT Monday...

Key Messages:

1) Isolated showers/storms this afternoon with heavy rain.

2) Heat Advisory in effect through this evening, another one
issued for tomorrow.

3) More widespread convection tomorrow, main concern is heavy
rain leading to localized flooding.

Remnants of post tropical Beryl were affecting the Mid MS Valley
this afternoon, and were expected to move towards the Upper
Midwest/Great Lakes regions on Wednesday. The southern and
central Appalachians were located well east of this disturbance,
with warmer mid levels and weak ridging in place. This morning`s
RNK sounding was moist adiabatic with some drier air just off
the surface, only supporting skinny/little CAPE this afternoon.
With no focus for convection today, expect only isolated showers
and thunderstorms along the higher terrain of the Blue Ridge
for a few hours, where the terrain will interact with southerly
winds to produce weak convergence/orographic lift. Afternoon
cumulus will dissipate tonight, but expect increasing cloud
cover overnight associated with the remnants of Beryl as it
nears to our NW. About the only concern will be moderate to
heavy rain, and WPC has highlighted the southern Blue Ridge in a
Marginal Risk for excessive rainfall for this afternoon which
seems warranted.

Very warm temperatures will drop into the low to mid 70s for
most tonight. Our environment for thunderstorms improves
tomorrow with a lead wave and cool front arriving ahead of the
main trough/remnants of Beryl moving towards the Great Lakes
region. That said, kinematic support and instability remain on
the low side, and SPC has almost the entire area in general
thunder. The atmospheric river does shift east along the front,
and ensemble situational awareness has specific humidity,
PWATs, and IVT all between 99th to maximum percentiles,
indicating that the ensemble is forecasting an event that falls
outside the 1979-2009 climatology for this time of year.

In other words, the humidity continues, and heavy rain leading
to flooding will be the main threat once again. It also means
another day of very high heat index values. A Heat Advisory has
been issued for parts of Southside VA and the VA and NC
Piedmont. Confidence is moderate for the forecast, but lower for
the extent of the heat advisory, which will depend on cloud
cover and the speed of the front, among other things.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 100 PM EDT Tuesday...

Key Messages:

1) Confidence is increasing for drier conditions during
Wednesday night into Thursday.

2) Chances of showers and thunderstorms should increase from the
east on Friday but decrease by Friday night.

As the remnants of Beryl pass well to the north across the
eastern Great Lakes on Wednesday night, a weak frontal
boundary will depart eastward but stall somewhere along the East
Coast. Shower and thunderstorm chances should diminish during
the night and into Thursday as drier air tries to arrive from
the west. Meanwhile, the frontal boundary will remain stuck
along the coast while waiting for a weak upper level low to
traverse along the western periphery of high pressure situated
across Bermuda.

This frontal boundary will buckle back to the west during
Thursday night and Friday as the upper level low passes
northward along the coast, which should increase the chance of
rain for North Carolina and Virginia. There may be notable cloud
cover and an easterly flow that could nudge temperatures lower
and limit the coverage of any storms. Heavy downpours could
accompany the convective activity east of the Blue Ridge due to
the moist air mass in place. Once the upper level low exits by
Friday night, it will free the frontal boundary to head offshore
as weak high pressure builds from the west.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 100 PM EDT Tuesday...

Key Messages:

1) Confidence is increasing for the heat and humidity to rise again
by early next week.

2) Chances of showers and thunderstorms could continue each
afternoon during this forecast period.

Although weak high pressure should spread across the Mid Atlantic on
Saturday, the air mass will not become appreciably cooler or drier.
Consequently, lingering moisture and orographical lift could spark
isolated showers and thunderstorms during Saturday afternoon. This
diurnal trend of scattered afternoon convection could continue for
the foreseeable future as the heat and humidity starts to climb
again as the flow turns toward the southwest. High temperatures in
the mid 90s with heat index values testing 100 degrees are possible
in the Piedmont for Sunday through Tuesday. As an upper level trough
approaches the Great Lakes by Tuesday, the coverage of afternoon
showers and thunderstorms could increase.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
As of 200 PM EDT Tuesday...

Isolated thunderstorms through this afternoon, mainly along the
Blue Ridge. After midnight, low level convergence increases as
the cold front enters the mountains from the west, with IFR/MVFR
stratus forming in eastern North Carolina overnight and
spreading north and west into southern Virginia. Otherwise
increasing mid and high clouds overnight and VFR.

A front moves through the area Wednesday, and expect more
widespread SHRA/TSRA, again with moderate to heavy rain. Some
ceilings in the MVFR range expected through evening.

Average confidence on the aviation forecast.


AVIATION OUTLOOK...

Expect the pattern to stay humid with daily chance of storms
mainly afternoon/evening through the week. IFR to MVFR fog at
night possible.

Mainly VFR outside storms and fog/low stratus mornings.

&&

.EQUIPMENT...
As of 200 PM EDT Tuesday...

KFCX Radar will be inoperative until the technicians can work on
on replacing the defective part by late this afternoon or
possibly Wednesday.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Heat Advisory until 8 PM EDT this evening for VAZ034-035-
     043>047-058-059.
     Heat Advisory from noon to 8 PM EDT Wednesday for VAZ033-034-
     043>047-058-059.
NC...Heat Advisory until 8 PM EDT this evening for NCZ004>006.
     Heat Advisory from noon to 8 PM EDT Wednesday for NCZ005-006.
WV...None.

&&

$$

SYNOPSIS...AMS/SH
NEAR TERM...SH
SHORT TERM...PW
LONG TERM...PW
AVIATION...SH
EQUIPMENT...SH/WP