260 
FXUS61 KRLX 291036
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
636 AM EDT Tue Jun 29 2021

.SYNOPSIS...
Hot and humid through mid-week with afternoon thunderstorms each
day. Cold front slowly passes through late week, then a slow 
moving upper low prolongs unsettled weather into the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 140 AM Tuesday...

For today, the area will remain slightly drier than the 
previous day although chances for diurnal showers and storms 
will still be on the table. High pressure weakens slightly, 
soundings have a cap although it has potential to be broken by 
late afternoon when temperatures reach into the low to mid 90's 
for most of the lowlands. Instability will be sufficient with 
high CAPE values and along with fairly decent lapse rates. Shear
will be low so the only way for strong wind will be out of a 
downburst. LI values are high and Dcape values are over 1000 
J/kg. Airmass type pop up storms could promote downbursts or a 
microburst under a heavy shower. A lot of drier air in the lower
levels will reinforce this as well, therefore strong winds 
would be the main threat from any storms that do develop. 

Freezing levels are high enough so hail should not be more than 
just pea sized in a stronger storm or downburst. However, we 
did receive reports of quarter size and 3/4 inch size hail 
yesterday so it is not out of the question for a storm today to 
produce larger hail. I like the total totals value (near 50) and
according to NAM and GFS soundings convective inhibition is 
nil. The 18Z NAM sounding near our CWA border over Vinton 
County, OH is looking really nice. For all of these various 
reasons, I went against guidance and have added slight to chance
probability for thunder into the grids for the entire area for 
the late afternoon to early evening. This is to account for a 
decent environment to potentially ignite some convection today. 

In summary, only expecting average airmass type thunderstorm 
potential with the stress on potential heavy downpours and the 
wind threat for collapsing storms. Also, cannot rule out strong
to borderline severe storms as we observed from yesterday. 
Finally, the aforementioned temperatures will make certain areas
close to heat advisory criteria if not borderline or above in 
localized places. Some of the convection that may take place 
might just subdue the heat threat, but this will unlikely happen
area-wide. Since large areas are not near the heat advisory 
criteria due to drier air, and lower dewpoints causing lower 
apparent temp values even with higher temps than yesterday, 
decided to hold off on any issuance of an advisory. Did Leave 
mention in the HWO. 

Into the late evening clouds mostly clear out and temperatures
only radiate down to about low 70's, and 60's for the higher 
terrain. We might have to deal with some fog again overnight, 
especially if any areas receive any kind of rainfall during the
daytime.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 309 AM Tuesday...
 
     Multiple rounds of showers/thunderstorms bring excessive
rainfall threat Wednesday through Thursday night...

Upper level ridge breaks down during the period as a trough
aloft dives down out of Canada and settles into the region by
Thursday night. At the surface, a cold front edges toward the
area on Wednesday and then takes its time settling 
southeastward through the region through Thursday night. A 
tropical airmass is advected northward in advance of the front 
with perhaps some moisture from Danny even getting involved with
models indicating PWATS approaching or even exceeding 2 inches
from late Wednesday into Thursday.

The approaching front should drive the development of
showers/thunderstorms over southeast Ohio Wednesday afternoon,
which will drop southeastward through time into Wednesday
evening. Forecast soundings show the cap is gone with quite a 
bit of CAPE and some dry midlevel air which would promote the 
potential for wind damage from the stronger storms. Storm 
motions remain rather slow and with the climbing PWATS, 
localized flash flooding will be possible from slow
moving/training cells, particularly over southeast Ohio and
adjacent portions of West Virginia.

The front works deeper into the region on Thursday and Thursday
night and this is when our excessive rainfall potential peaks 
with numerous to widespread showers/thunderstorms expected.
Overall, one to two inches of rainfall is likely across the
region during this period, with heavier amounts possible.

Temperatures will be on a downward trend, but may still reach 90
in the lowlands on Wednesday before being held down into the 
70s to low 80s on Thursday.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 309 AM Tuesday...

The trough that brings our unsettled short term forecast closes
off and drops over the region during the weekend. This does not
bode well for the holiday weekend with a continuation of
unsettled weather and cooler temperatures likely through the
Fourth before things begin to improve by Monday. I do not think
it will rain all day every day, but scattered showers and a few
thunderstorms are a good bet, especially each afternoon. 
Daytime temperatures are forecast to remain in the 70s to lower 
80s in the lower elevations through Sunday before moderating 
well into the 80s on Monday.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
As of 630 AM Tuesday...

Other than some valley fog that is restricting CRW/EKN, VFR and
weak southerly flow is forecast to dominate through the period.
During the afternoon, expecting some Cu to form along with some
possible convection that may promote a shower near or over a 
terminal. This may reduce VIS temporarily to MVFR or worse 
depending on the intensity, however VIS should bounce right back
to VFR. Thunderstorm potential at this point is low however
place VCTS in TAFs for the later afternoon at all terminals.
Thereafter, things should be quiet until the next morning when 
clouds clear out fairly well out opening the door for some more
fog, especially to sites that receive any rainfall this
afternoon/evening.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY...
     
FORECAST CONFIDENCE: Medium.
     
ALTERNATE SCENARIOS: Depending on how much convection that may 
occur near terminals this afternoon, restrictions to VIS/CIGs 
may be more abundant that what is in the TAFs.

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    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    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  L    L    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  L    L    H    H    H    H    H    H    H    H    H    H

AFTER 12Z WEDNESDAY...
No widespread IFR currently expected.

&&

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

&&

$$
SYNOPSIS...ABE/JZ
NEAR TERM...JZ
SHORT TERM...ABE
LONG TERM...ABE
AVIATION...JZ