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-- Discussion containing changed information from previous version are highlighted. --
047
FXUS61 KRLX 160730
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
330 AM EDT Sun May 16 2021

.SYNOPSIS...
-- Changed Discussion --
A warm front affects the area first half of next week with high
pressure building in with a notable warming trend.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
As of 330 AM Sunday...

A shortwave crossing through the area may bring a few light
showers into the area during the day; however, dry air in the
low levels will need to be overcome for rain to reach the
ground. The best chances for rain showers today will be along
the mountains during the morning hours. In the afternoon, any
showers are expected taper off and some clearing may occur as
the shortwave shifts east. Meanwhile, a warm front will be slowly
approaching the area from the south. Rain chances will return by
late tonight and are expected to increase south to north across
the area as this front nears.

Today`s temperatures are expected to reach low 70s in the
lowlands and 50s to 60s in the mountains. Tonight will be a bit
warmer than the previous night with lows in the 50s in the
lowlands and 40s in the mountains.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 215 AM Sunday...

A stream of Gulf moisture ends its circuitous path north
through the southern and central plains then eastward
paralleling a slow moving elevated warm front. Atop this,
synoptic ascent associated with the right rear quadrant of a
departing 100KT H250 jet core should yield a fairly narrow swath
of mainly light rainfall roughly oriented WNW-ESE while areas
away from the boundary remain largely dry through the day. Still
have some spread in the models regarding frontal position with
the GFS and EC solutions suggesting it could make it as far
north as I-64 while WRF based solutions keep it mainly just
south of our southern border. Will continue to depict a slightly
wider PoP swath to account for this spread, but this should
continue to tighten over the next couple cycles. Rainfall
amounts will largely be contingent on the proximity of the
frontal zone to the aforementioned upper level divergence with
around a quarter of an inch possible with the south offset
frontal zone with the WRF based solutions and close to half to
one inch with the EC/GFS with better alignment of upper forcing
and theta-e feed. Instability will be quite limited given
substantial cloud cover associated with the front and poor mid-
level lapse rates, but couldn`t rule out a few rumbles of
thunder.

Better forcing for ascent largely exits the region with mid-level
heights beginning to build Tuesday while the elevated warm front
remains in the vicinity of our southern counties. This will yield
some continuation of mainly light showers during the morning hours
with a few rumbles of thunder possible by the afternoon as modest
surface based instability builds with heating away from
lingering cloud coverage associated with the remnants of the
elevated warm front across the south.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 215 AM Sunday...

Ensemble guidance continues to trend toward a stronger East Coast
ridge/heat dome pattern for the extended forecast with rather tight
interquartile EPS/GEFS ranges lending confidence to the forecast.
Ensemble means now depict +2 to 2.5 sigma, near climatological
maximum height values for this time of the year through the
column Wednesday into the weekend. Both model families support a
wobbly surface high meandering between the Mid-Atlantic coastal
plain and the upper TN valley. A substantial plume of strong
mid-level lapse rates sourced from N Mexico will remain confined
to the high plains of W TX under sustained southerly flow with
an extended diurnal cycle of severe for those locales. Given a
bit stronger ridging than the previous forecast cycle and a bit
more marginal low level moisture in place in our neighborhood,
think any afternoon pop-up convection might be hard to come by
for at least Wednesday through Friday and will not make any
changes to central guidance indicating a clean forecast.

As the upper ridge begins to become slightly suppressed equatorward
heading into the weekend, may see some of the aforementioned steeper
lapse rates associated with the elevated mixed layer beginning to
try to work into the northern half of the forecast area amid
increasingly westerly flow. This potentially yields some slightly
better TS chances for the afternoon hours Saturday and Sunday
depending on degree of upstream overturning, but difficult to
justify more than isolated coverage this far out with models
trending toward a stronger ridge.

Daytime highs through the period will run 5 to 10 degrees above
normal for this time of the year with overnight lows to near just
above normal values given relatively tame low level moisture.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
As of 135 AM Sunday...

VFR conditions are expected for the rest of tonight though mid to
upper level clouds will continue to move into the area. Ceilings
will begin to lower during the day as a warm front approaches
to the south; however, sites should remain VFR throughout the
period. Chances for rain showers will exist mainly along and
near the mountains during the day, so have maintained -SHRA for
CKB, EKN, BKW, and CRW.

Winds start off calm overnight, then will be light for the rest of
the 06Z TAF period.

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

FORECAST CONFIDENCE: High.

ALTERNATE SCENARIOS: Extent and timing of -SHRA during the day
may vary from forecast. MVFR may occur at BKW this evening.

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                              SUN 05/16/21
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    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  H    H    H    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 06Z MONDAY...
IFR possible in showers and thunderstorms Sunday night into
Monday.

&&

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

&&

$$
SYNOPSIS...JP/JLB
NEAR TERM...JLB
SHORT TERM...JP
LONG TERM...JP
AVIATION...JLB