418
FXUS61 KRLX 040756
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
356 AM EDT Tue Jun 4 2024

.SYNOPSIS...
Warmer and quieter weather for today, cannot rule out an
isolated shower or storm. Showers and storms return Wednesday
ahead of a cold front on Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 200 AM Tuesday...

Weak surface high pressure sort of fleets toward the southeast.
The good news is that upper level ridging will still cover the
area and keep most activity from developing. However, we cannot
rule out an isolated shower or storm with a 040FT Cu deck
forming in the afternoon. With temperatures climbing into the
mid to upper 80`s this afternoon, plenty of instability will be
available but we do have small caps to keep any agitated Cu from
fully developing.

One can imagine that activity can be still possible which is
why POPs and thunderstorm probability were added into the
forecast, but it should be very isolated in nature. Went with a
blend of Hi-res guidance which equated to slight chance to
chance POPs scattered among the area for this afternoon and
evening. Thereafter, chances increase late tonight, but thinking
it could increase during the late evening as well, in response
to a cold front moving closer to the area with activity out
ahead of it.

Lapse rates are well above environmental and PWATs are around
an inch with DCAPE values very high so there could be some
decent showers, but not thinking anything excessive or ones that
would cause water issues because we are dry in the mid to upper
levels. There is very weak shear and boundary layer flow with
no upper level support so anything that does form will be pulse
like cells that may move fairly slowly. The main focus will
likely be the mountains with smaller caps and elevated heat
effect helping out the development of cell growth.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 355 AM Tuesday...

Showers and thunderstorms may be ongoing Wednesday morning, as a
series of weak southern stream ripples cross, out ahead of a
better-defined mid-upper level short wave trough that crosses
late Wednesday night. This activity may limit heating ahead of
the main short wave, which will drive a surface trough/weak cold
front through the area overnight Wednesday night into early
Thursday morning.

The best chance for the strongest thunderstorms is ahead of
these nighttime features Wednesday evening. However, even then,
CAPE of just 500-1500 J/kg CAPE and modest shear of 20-30 kts
is not likely to support a severe threat, although strong wind
gusts are possible then. The CAPE does extend well up through
the hail growth layer, with the equilibrium level all the way up
past h20 Wednesday afternoon and evening.

Higher dew points, CAPE and shear just northwest of the forecast
area and closer to a low pressure center moving northeastward
through the eastern Great Lakes support a better chance for at
least marginally severe weather, as depicted in the SPC day one
convective outlook. A more intense low and better low level
south to southwest feed ahead of it could eventually seep the
severe weather threat southeastward into northwest reaches of
the forecast area Wednesday evening. The development of the low
level jet after sunset could also prolong the threat long
enough to carry it into the forecast area then.

PW values climb to the neighborhood of 1.75 inches Wednesday
afternoon, about as high as it gets in this area this time of
year, so heavy downpours are possible Wednesday afternoon and
evening, with a local high water threat wherever heavier
thunderstorms hit urban or other low lying, sensitive areas.

Shower and thunderstorm coverage decreases west to east after
sunset Wednesday night, as the mid-upper level short wave and
surface trough/weak cold front cross.

A large mid-upper level low over the west-central portion of
the continent digs in over the Great Lakes Thursday through
Thursday night, a short wave trough pivoting around the south
side of it drives a surface cold front through the area Thursday
afternoon and evening.

While the surface trough/weak cold front brings negligible if
any cooling, it does knock PW values down to around an inch.
Moreover, it takes out instability given the drier column and,
more notably, a stout mid-level cap that develops between the
last southern stream short wave exiting Wednesday night, and the
main mid- upper level system digging in. As such, convection
will be shallow, with minimal to nil threats ahead of the main
front the afternoon of June 6, even amid increased shear.

To be sure, precipitation coverage overall will be isolated to
scattered Thursday afternoon, and the convection will shut off
promptly at sunset, setting up a dry night.

Central guidance reflects above normal temperatures, until
Thursday night, with lows then finally closer to normal.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 355 AM Tuesday...

Cooler, drier weather is on tap for the weekend, as a long wave
trough in the east/ridge in the west pattern sets up,
notwithstanding a monkey wrench thrown in by the GFS for the
latter half thereof.

Full discussion to follow shortly.

As of 1245 PM Monday...

The cold front will be traversing the area early Thursday, but
shower/thunderstorm chances will remain through the day as it
crosses. Only a few isolated showers or a stray storm remains
possible Thursday, as the atmosphere appears to be capped with
drier air intruding as this front passes. Was not keen to cut
PoPs Thursday afternoon though with temperatures projected to
be in the upper 70s and 80s for a large chunk of the area, still
any pop-up activity will be short-lived and will not boast any
significance. Winds will be breezy at times in the afternoon
behind this front, especially across the ridges.

The pattern then looks to remain not quite as warm, with
diurnal precipitation chances through the weekend as a behemoth
of an upper-level low drops out of Canada and remains just
north of the area. Several shortwaves look to move through the
upper-level pattern this weekend allowing for chance PoPs each
afternoon through Sunday. Temperatures will fall from
seasonable upper 70s and 80s down into the 70s across the
lowlands, with the mountains staying in the 60s and low 70s.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
As of 140 AM Tuesday...

This morning fog has developed which is affecting CRW/PKB/BKW
and expecting EKN to go down through the morning. Once the fog
lifts around 12-13Z VFR will take back control through the
period. Some Cu will form this afternoon and possibly promote
an isolated shower or storm which may affect a site in
particular the eastern sites. This would bring down VIS
temporarily and CIGs should stay around 040FT or above today.
More activity will come to fruition for Wednesday as showers
and storm will become more prevalent.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY...

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Foggy conditions may vary from the
forecast this morning and could get into sites that are not
suppose to go down in VIS.

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                              TUE 06/04/24
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EDT 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
CRW CONSISTENCY  H    H    L    M    L    L    H    H    H    H    H    H
HTS CONSISTENCY  H    M    M    M    M    M    M    H    H    H    H    H
BKW CONSISTENCY  M    L    L    M    L    L    H    H    H    L    M    M
EKN CONSISTENCY  L    L    L    M    M    M    M    L    M    M    M    H
PKB CONSISTENCY  H    H    L    L    L    M    M    H    H    H    H    H
CKB CONSISTENCY  H    H    M    M    M    M    H    H    H    H    H    H

AFTER 06Z WEDNESDAY...
Brief IFR conditions are possible in showers and thunderstorms
at times Wednesday into Thursday.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.

&&

$$

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