592
FXUS61 KRLX 081014
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
614 AM EDT Mon Jul 8 2024

.SYNOPSIS...
Heat builds today and through the week. The remnants of Beryl
cross Tuesday night/Wednesday. The weather pattern then settles
into a typical summer regime, with mainly diurnal storms.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 605 AM Monday...

No changes needed to the forecast. Seeing a few areas of fog on
visible satellite. This is most notable across the Greenbrier
River Valley and the southern lowlands of West Virginia.

As of 330 AM Monday...

Key Points:

  * Heat Advisory in effect from noon today until 8 PM this evening.

  * Heat index values up to 100 degrees across portions of the WV
    lowlands this afternoon.

High pressure will stick around today, but a stationary front to our
east will create some uncertainty with the forecast this afternoon.
An inverted trough will stick around over the area through the day,
allowing for some mid and high level clouds to filter through during
the day.

The heat will be the main focus for the near term with above normal
temperatures expected today. Low to mid 90s will be common across
the lowlands with the mountains ranging from upper 70s to the upper
80s. Afternoon dew points will be in the upper 60s to around 70 for
most, which will create a muggy and oppressive humidity.

Models are starting to trend the dew points downwards though, thus
lessening the humidity. Still, the blend of models keeps heat index
values in the upper 90s to around 100 across portions of the West
Virginia lowlands. Opted to issue a heat advisory to cover any
localized heat index values that will likely reach or exceed 100
degrees across the highlighted counties this afternoon. Locations
most susceptible will be urbanized areas and any low- lying
valleys.

While most of the area will be dry today, the chance for showers
and thunderstorms will creep in across the eastern and northern
mountains this afternoon. The culprit being the previously
mentioned stationary front which looks to bend back to the west
this afternoon, sustaining a surface trough across the area.

SPC does have general thunderstorm probabilities across the
mountains and portions of the foothills and lowlands of West
Virginia this afternoon. The higher chances will remain across
the mountains though, where greatest source of lift will be.
Specific locations would be the Greenbrier River Valley into
Pocahontas County and across southwest Virginia Convective
models are starting to downplay the possibility though, keeping
most of the activity outside of our area to the east. Any
activity that does form would lack longevity and will cease to
exist after sundown.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 325 AM Monday...

A developing early-week heat wave is interrupted by, of all
things, a tropical system.

Mid/upper-level ridging ahead of the approaching remnants of
tropical system Beryl brings hot, mainly rain-free weather on
Tuesday. There may be a pop-up afternoon thunderstorm over the
mountains Tuesday, but then the chance for showers and
thunderstorms gradually increases Tuesday night, as the remnants
of Beryl approach.

Beryl becomes a full-fledged extratropical cyclone as it gets
absorbed by the southern stream tonight into Tuesday, and draws
cooler air around its back side. By Wednesday, it becomes
stacked through the mid-levels, and pulls its associated cold
front through the forcast area sometime on Wednesday.

Shear associated with the extratropical system will combine with
the very warm, humid and modestly unstable air mass in place,
can lead to marginally severe thunderstorms into the middle Ohio
Valley Tuesday night, especially as dew points increase in
response to the arrival of the tropical moisture associated
with Beryl. However, this increase may not occur until well
into the overnight hours Tuesday night.

SPC has maintained the marginal risk for severe thunderstorms
just into northeast Kentucky along the Ohio River for the
Tuesday/Tuesday night period, mainly for damaging wind, but
also a non-zero tornado threat given an increase in low level
flow, wind shear and storm relative helicity associated with
the system.

While showers are likely at some point Wednesday as the system
pulls through, the potential for thunderstorms and especially
strong to severe storms, depends upon the timing of the frontal
passage relative to diurnal heating. The guidance envelope
allows the front to cross virtually anytime on Wednesday. SPC
has only highlighted general thunder for Wednesday/Wednesday
night for now.

While rainfall can be heavy Tuesday night and Wednesday in the
tropical air mass, the low center tracking well north and west
of the area should limit the duration of any heavy rainfall

The chance for showers and thunderstorms decreases Wednesday
night, with the exodus of the system coincident with loss of
daytime heating.

Central guidance temperatures and dew points result in heat
indices in the mid 90s to around 100 for much of the central and
southern lowlands, close to necessitating another heat advisory
as time gets closer. However, forecast highs are near the upper
end of the not very wide guidance envelope. After a very warm
and humid Tuesday night, temperatures on Wednesday will be
stifled only by the clouds and showers associated with Beryl.
Faster solutions depicting the dry slot associated with the
system crossing the area behind the front Wednesday afternoon
would allow it to become hot once again, but with dew points
falling back into the 60s. Wednesday night will be a bit cooler
in the wake of the exiting system, but with lows still above
normal.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 325 AM Monday...

The weather pattern settles into a typical mid-summer regime
this period, in the wake of the exiting tropical remnants, very
warm and humid with mainly afternoon and evening showers and
thunderstorms. The chance for precipitation is greatest early
on, as short wave troughs cross in the west to northwest mid-
upper level flow. By the beginning of next week, building
ridging may push the southern stream, and ring of fire along the
edge of it, far enough north and east to limit the chance to
increasingly far northeastern portions of the forecast area.

After near normal temperatures to start, central guidance
reflects the heat gradually building through next weekend, with
modestly high humidity.

&&

.AVIATION /10Z MONDAY THROUGH FRIDAY/...
As of 120 AM Monday...

VFR conditions to start with passing mid to high level clouds.
Fog could form across the river valleys overnight, mostly across
the northern mountain valleys. One caveat to fog formation
tonight is cloud cover. A surface trough to our southwest is
spawning cloud cover which will move over throughout the
morning, likely hindering fog formation. Still expecting
MVFR/IFR VIS restrictions with the worst conditions expected at
EKN.

VFR takes over by ~12-13Z this morning and will continue
through the day today. Winds will be calm until sunrise, then
light and variable with mostly a westerly direction afterwards.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...

FORECAST CONFIDENCE: High overall, but low for fog.

ALTERNATE SCENARIOS: Timing and extent of fog development could
vary from the forecast.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

DATE               MON 07/08/24
UTC 1HRLY       09   10   11   12   13   14   15   16   17   18   19   20
EDT 1HRLY       05   06   07   08   09   10   11   12   13   14   15   16
CRW CONSISTENCY  M    M    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  L    L    L    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 12Z TUESDAY...
Mountain river valley fog possible again Tuesday morning. Brief
IFR possible in and near thunderstorms Wednesday.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Heat Advisory from noon today to 8 PM EDT this evening for
     WVZ006-013>015-025>027.
OH...None.
KY...None.
VA...None.

&&

$$

SYNOPSIS...TRM/LTC
NEAR TERM...LTC
SHORT TERM...TRM
LONG TERM...TRM
AVIATION...LTC