453
FXUS61 KRLX 061831
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
231 PM EDT Sat Jul 6 2024

.SYNOPSIS...
High pressure brings dry weather for the weekend. Increasing
southwesterly flow yields increasingly hot and humid conditions
Monday. Rain chances return for mid-week and beyond.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 215 PM Saturday...

The next 30 hours look about as benign as can be as far as
summer weather goes across the region. High pressure will remain
overhead, keeping us dry, with just puffy fair-weather cumulus
noted over the CWA. Most of those clouds should dissipate
overnight, and clear and calm conditions will combine with the
recent rain to allow for fog formation across the area, densest
in the valleys. We could see some patchy fog form as early as
midnight, especially in the higher valleys, and it will spread
from there through the rest of the night. Most fog should
dissipate within a couple hours of sunrise, and Sunday looks to
be another sunny to partly cloud day across the area.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 1240 PM Saturday...

Mid-level troughing moving into the Upper Mid-West Sunday night will
yield increasing southwesterly flow opening up the taps on Gulf
moisture into the region once again. This yields surface dew points
increasing back into the lower 70s by Monday afternoon amid
afternoon temperatures across the lower elevations in the lower to
mid 90s for both Monday and Tuesday with heat index values
approaching triple digits. Will need to keep an eye on potential for
a heat advisory for both days. These hot and humid days will also
yield at least some atmospheric instability, despite rather poor mid-
level lapse rates with isolated to perhaps scattered diurnally
enhanced convection with the best chances closer to the higher
terrain. The aforementioned mid-level troughing moves into the
Middle Ohio Valley late Tuesday afternoon with an associated cold
front. This should serve to focus chances for showers and storms.
Deep layer shear increases to around 40KTs Tuesday afternoon,
contingent on timing of cold frontal passage this could yield a
window for some organized stronger convection, overall limited by
instability due poor lapse rates. With steering flow nearly normal
to frontal motion could see some training with very efficient
rainfall production should instability come in a bit stronger than
advertised, but for now the threat for both severe storms and
flooding appears low.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
As of 1240 PM Saturday...

In the wake of cold frontal passage Tuesday night into Wednesday,
upper level southwesterly flow progressively weakens as high
pressure over the Atlantic bulges east. This effectively cuts the
region off from better mid-level lapse rates from the Desert
Southwest while continually pumping tropical moisture toward the
Atlantic Coastal Plain. This yields 99th percentile moisture values
on the coastal plain with mere 80th to 90th percentile (around 1.6
to 1.9" PWATs) over a bulk of the forecast area, highest closest to
the mountains. Despite the aforementioned poor mid-level lapse
rates, afternoon highs in the mid to upper 80s (lowlands) and lower
to mid 70s (mountains) should yield diurnally enhanced convection
through the balance of the work week with the greatest chances in
the vicinity of the higher terrain in diurnal upslope flow. Flow
through the column will be fairly weak with deep layer shear ranging
from around 10 to 20KTs. This may yield somewhat more persistent
cellular clusters than dead flow up and down convection and with the
aforementioned juicy column coupled with deep warm cloud depths,
this could yield some localized flooding issues in any more
persistent and efficient convection.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
As of 200 PM Saturday...

VFR conditions will prevail into the evening with just some
puffy fair-weather cumulus clouds, mainly 040-080. Those should
dissipate by or soon after sunset. The clear and calm conditions
overnight, combined with recent rainfall the past few days,
should allow for plenty of fog formation across the area, and we
have all TAF sites except BKW, but the fog likely won`t be far
away, and it wouldn`t be surprising to see them get some MVFR
stratus. Regardless, due to line limitations, did have all sites
end fog by 12z, but a few spots (especially EKN) could hang onto
it a bit beyond then.


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

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Timing and extent of dense fog development
overnight tonight could vary from the forecast.

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       19   20   21   22   23   00   01   02   03   04   05   06
EDT 1HRLY       15   16   17   18   19   20   21   22   23   00   01   02
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    M
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 SUNDAY...
LIFR to VLIFR in dense fog briefly possible late tonight into
Sunday morning. More valley fog possible Sunday night, but not
as confident.

&&

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

&&

$$

SYNOPSIS...FK/JP
NEAR TERM...FK
SHORT TERM...JP
LONG TERM...JP
AVIATION...FK