-- Discussion containing changed information from previous version are highlighted. --
690
FXUS61 KRLX 031122
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
722 AM EDT Mon Jun 3 2024

.SYNOPSIS...
Possible mountain showers and storms this afternoon and
evening. Warmer with a brief dry spell for most Monday and
Tuesday. Disturbances Wednesday ahead of a cold front Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 145 AM Monday...

Relatively settled day with some exceptions. It may be partly
unsettled this afternoon due to the elevated heat effect across
the mountains which will promote some shower and storm
potential during the afternoon and into the evening. Outside the
mountains, the lowlands should stay relatively dry, but cannot
rule out a rogue shower or storm, but probability was too low to
add into the forecast at this time. Soundings look fairly good
with plenty of instability, high DCAPE and High PWATs to support
diurnal convection, but a small cap may suppress the potential
for thunderstorm activity outside the mountains.

Most of the instability will be wasted due to weak surface high
pressure and ridging aloft. Hi-res and short term models have
most of the potential activity across the mountains except for
the NAM12 and NAM4K, therefore took a blend of the previous
forecast and newer guidance along with making some custom
tweaks for POPs and thunderstorm probability to account for the
NAM12 and NAM4K being aggressive. However, that is a hint that
there may be some rogue storms outside the higher elevations,
therefore confidence is slightly low for placement of storm
potential under this semi-dirty high pressure system.

Made a model blend for temperatures which equated to about a
degree or two lower than central guidance for the daytime highs
and lows. Mid 70`s to low 80`s are expected for the lowlands and
upper 60`s to mid 70`s for the mountains. For lows tomorrow
morning expect around low 60`s for the lowlands and mid to upper
50`s for the mountains.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 350 AM Monday...

Tuesday brings warmer, mainly dry weather, as surface high
pressure gives way to southerly flow, and mid-upper level
ridging crosses. Elevated heat source diurnal convection is
again possible over the mountains.

The first of a series of weak southern stream short wave
troughs ejecting out ahead of a large mid-upper level system
over the west-central portion of the continent may bring showers
and thunderstorms into the area as early as overnight Tuesday
night, with a slight chance depicted. The greater likelihood
for showers and thunderstorms is Wednesday, particularly
during the afternoon and evening, as the second in the series of
short waves crosses in concert with diurnal heating.

Despite the favored timing, clouds and showers early in the day
limit heating, and 0-6/0-8 km bulk shear is forecast in the
15-25 kt range, perhaps climbing above 30 kts after sunset
Wednesday night. Thunderstorms could be strong Wednesday
afternoon amid 2500-3500 J/Kg surface-based CAPE well through
the hail growth layer, with the equilibrium level all the way up
around h15, but severe weather potential is low unless we could
realize better shear before sunset.

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 also possible, 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, particularly as one last southern
stream short wave and a surface trough/weak cold front cross.

Central guidance reflects above normal temperatures, with
negligible if any cooling with the trough/frontal passage
Wednesday night.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 425 AM Monday...

The large mid-upper level low over the west-central portion
of the continent shifts east, setting up a long wave trough in
the east/ridge in the west pattern for the latter half of the
week. This brings cooler weather, backing us into spring as we
pull within two weeks of the summer solstice.

As the low 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 evening. This is interesting to write about. 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.

The large mid-upper level low digs into and then swirls about
the northeastern states heading into the weekend. The cool air
aloft atop strong June surface heating could promote shallow
diurnal convection beneath the stout mid-level inversion. Timing
and extent is also likely to be modulated by short wave troughs
pivoting through around the parent low. This inversion may
eventually erode over the weekend, as the low swirls closer to
the area, allowing for deeper convection. Even then, CAPE is
expected to remain narrow.

Central guidance reflects temperatures falling back to normal
Thursday and Thursday night, and then below normal heading into
the weekend, at least on highs. There is a spread that opens
up, depending upon the amplitude of the mid-upper level low, and
how far south it tracks, with central guidance leaning toward
the high side of the spread on highs this weekend. There is not
much room in the spread for below normal lows.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
As of 720 AM Monday...

Outside some fog this morning, which will break up soon. VFR
will then takeover by late morning with chances of showers and
storms near EKN/BKW, but probability is fairly low. We cannot
rule out an isolated shower or storm elsewhere but again the
probability is low. A Cu field will likely develop during the
afternoon, but will be more heavily noticeable along the
mountains. Winds will be very light due to high pressure
slackening the pressure gradient. Another good opportunity for
fog development once again tonight.


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

FORECAST CONFIDENCE: Medium to high.

ALTERNATE SCENARIOS: VIS restrictions may vary from the
forecast this morning.





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.

UTC 1HRLY       11   12   13   14   15   16   17   18   19   20   21   22
EDT 1HRLY       07   08   09   10   11   12   13   14   15   16   17   18
CRW CONSISTENCY  M    M    L    L    H    H    H    H    H    H    H    H
HTS CONSISTENCY  M    L    L    M    H    M    H    H    H    H    H    H
BKW CONSISTENCY  M    H    M    H    H    M    M    H    H    H    H    H
EKN CONSISTENCY  L    L    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  M    L    M    H    H    M    M    H    H    H    H    H
CKB CONSISTENCY  M    M    M    M    H    H    M    H    H    H    H    H

AFTER 12Z TUESDAY...
Brief IFR conditions are possible in showers and thunderstorms
at times Wednesday into Thursday.
-- End Changed Discussion --

&&

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

&&

$$

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