527
FXUS61 KRLX 071742
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
142 PM EDT Tue May 7 2024

.SYNOPSIS...
Daily chances for showers and storms continue, with the
frequency of storms posing concern for localized flooding.
Severe storms are possible today and Wednesday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 1208 PM Tuesday...

Showers and storms, some strong to severe are expected in the near
term period. A large low pressure system will continue to meander
across the northern plains, sagging south tonight into Wednesday,
filling as it does so. Convection across the midwest last night into
this morning, should weaken as it continues eastward, but could
reinvigorate later this afternoon/evening as it travels eastward
towards our area into an increasingly unstable atmosphere, along
with additional rounds of storms expected overnight from additional
shortwaves crossing the area. Strong cape on the order of around
2000 J/Kg, and increasing shear of 50+ kts, along with curved
hodographs and low lcl heights, lead to threats for all hazards,
including large hail, and strong damaging winds/downbursts, and
perhaps an isolated tornado, although the greater risk for that
looks to lie to our west.  Period of greatest threat appears to be
by 20Z through 03Z.

There may be a bit of a lull in the activity for the first part of
Wednesday, but another potent wave will move through the area later
Wednesday evening into the short term period, with heavy rains and
severe weather potential, although this period damaging winds and
hail look to be the primary risks, with a lesser risk for
tornadoes, although it cannot be completely ruled out either.

In addition, increasing southwesterly flow across the area should
allow for PW values to rise into 1.4 to 1.5 inches today, and
approach 1.7 inches on Wednesday, and this with areas of saturated
soils from recent days, elected to issue a flood watch for flash
flooding across parts of the region. That will include the potential
for any convection today, plus additional rounds on Wednesday, and
continues into Thursday morning.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 230 AM Tuesday...

A triple point low pressure system out over the Midwest will
lift a front through the area starting this period. Frontal
passage is forecast to occur across Wednesday as the front
surges south and then lifts north as a warm front when the low
gets closer to the area. Bouyancy associated in the warm sector
will allow for possible thunderstorms some of which could become
severe due to high wind shear. With mid to upper 60F dewpoints
advecting in from the southwest the airmass is quickly going to
recover and support thunderstorm activity throughout the day.

The aforementioned system will push in a cold front on Thursday
which will have the ability to support supercell activity
during the day. All hazards can be associated with this system
as it is forecast to move across toward the northeast just
grazing the northern periphery of our CWA. Heavy downpours will
be a thing to consider with flash flood guidance very low in
certain area, especially along the Ohio River on the WV side. A
few tornadoes cannot be ruled out of the broken line expected to
enter the CWA from the southwest according to Hi-res models.

Damaging wind and large hail are possible as well with severe
indices indicating high shear for prolong hail growth lifted in
the updrafts, plenty of instability and high DCAPE values which
will support downbursts potential. This activity will likely
extent through the afternoon and evening on Thursday.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 140 PM Tuesday...

The weather remains active but nowhere near as impactful in the
long term, compared with the near and short term periods.

Friday morning finds the area in west to northwest low level
flow between low pressure off to the northeast and moving away
to the northeast with its associated mid-upper level short wave
trough, and surface high pressure approaching from the west.

There is another mid-upper level short wave trough that crosses
Friday afternoon, but models evince that enough low level cool
air comes in behind the cold front to create an unbreakable mid
level inversion 6 kft agl south to 12 kft agl north. Thus, only
low top showers are anticipated, with no hail or impactful wind
gust threat even where if we do manage charge separation.

The weather dries out Friday night as the high ridges in from
the southwest. However, another mid-upper level short wave
trough and surface low intercept that ridging as they pass
north of the forecast area Saturday afternoon and evening. This
gives rise to the chance for mainly afternoon and evening
showers and perhaps thunderstorms in the mixed layer below the
inversion which, at this point, can be eroded.

Another short wave trough pivots through Sunday afternoon, all
this around evolving broad mid-upper level low pressure over
eastern Canada, again with the mainly afternoon chance for
showers and perhaps a thunderstorm. The mid-level inversion
manifests as just a less steep lapse rate layer, but it and dry
low level air limit CAPE and keep it narrow.

We may manage daytime dry whether at times early next week
depending upon timing of frequent but weak weather systems
moving through.

Central guidance reflects below normal temperatures Friday and
this weekend, before climbing back to and eventually above
normal early next week, as mid-upper level ridging tends to
build amid the weak systems.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
As of 638 AM Tuesday...

The area remains socked beneath low level stratus this morning
with pockets of low visibility due to fog. Should see a slight
improvement in ceilings to MVFR later on this morning and
further into low-end VFR by the early afternoon. Showers and
storms begin to sprout upstream in the Ohio Valley this
afternoon and will propagate eastward into the area heading into
this evening and tonight. Some storms may be capable of
producing hail, damaging wind, and tornadoes in the event
activity reaches severe thresholds. For aviation purposes, brief
vsby reductions may also accompany convection today.

For tonight, storm activity winds down during the early morning
hours Wednesday, leaving behind excessive moisture to support
low ceilings once more. A strong low level jet moves into the
region overnight and may promote LLWS across the area into
Wednesday morning.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...

FORECAST CONFIDENCE: Medium, low within areas of fog.

ALTERNATE SCENARIOS: Timing of ceiling improvements may vary
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       15   16   17   18   19   20   21   22   23   00   01   02
EDT 1HRLY       11   12   13   14   15   16   17   18   19   20   21   22
CRW CONSISTENCY  H    M    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    M    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    M    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    M    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 18Z WEDNESDAY...
IFR conditions at times in showers and thunderstorms into
Thursday, and in fog and stratus on mornings following showers
and thunderstorms.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Flood Watch through Thursday morning for WVZ005>009-013>017-
     024>026.
OH...Flood Watch through Thursday morning for OHZ075-083>087.
KY...Flood Watch through Thursday morning for KYZ101>103-105.
VA...None.

&&

$$

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