719
FXUS61 KRLX 010736
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
336 AM EDT Wed May 1 2024

.SYNOPSIS...
Dense fog this morning as a cold front exits. High pressure
brings dry weather with a warming trend today into Friday.
A cold front brings showers and storms this weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 200 AM Wednesday...

A cold front has moved off to our northeast and a surface trough
sits east of the Appalachian Mountains. Skies will continue to
clear and winds will calm as a result. These factors, paired
with lingering low-level moisture from recent rainfall, will
allow the perfect setup for widespread dense fog with low
visibilities this morning.

Sheltered river valleys and mountain valleys with poor drainage
winds will see the lowest visibilities, which could be below a
quarter of a mile at times. A statement has been issued across
the entire forecast area for visibilities of a quarter of a mile
or less that will likely be observed within thicker fog columns.
Caution should be used traveling this morning.

Fog will lift and clear after sunrise this morning and a dome
of high pressure over the Deep South will move up over the area.
This feature will reinforce dry weather and invoke the start of
another warming trend under southwesterly flow. Temperatures
today look to be fairly warm with highs in the low to mid 80s
across the lowlands; 60s to high 70s in the mountains.

Another round of fog looks possible again tonight into Thursday
morning, though will not be as widespread and intense with low-
level moisture drying out this afternoon. Overnight lows will be
in the 50s again as we decouple under the high pressure.
&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
335 AM Wednesday...

Thursday morning is likely to find a nearly stationary front
draped west to east just north of the area. This front will lift
north as a warm front, Thursday through Friday, ahead of a cold
front approaching from the west. There may be showers and
thunderstorms along and north of the front back in central Ohio
Thursday morning, where the front is already beginning its
northward move. This activity should move northeast, remaining
north of the forecast area, as the northward movement of the
front progresses east.

This leaves the area in very warm, dry air, with plenty of
sunshine on Thursday once any morning fog burns off.

As the cold front and its associated southern stream short wave
trough move into the area Friday, clouds will start to increase
ahead of it Thursday night in the form of cirrus and
stratocumulus, and then any sunshine Friday morning will give
way to lowering and thickening cloudiness, with showers and
thunderstorms becoming a possibility by the end of the day.

The forerunner increase in cloud, and modest dew points in the
lower 60s, likely contribute to modest instability Friday
afternoon, with CAPE less than a KJ/kg. Given modest low to mid
level flow.shear, thunderstorms are not expected to be
especially strong, but they can produce heavy downpours and gusty
winds in the middle Ohio Valley by late in the day.

Deterministic central guidance highs are now in line with the
50th percentile guidance is rather high for daytime highs both
days, and are comfortably below record highs. Thursday night
will be mild, although decoupling could allow lows lower than
central guidance.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...

As of 100 PM Tuesday...

Increasing southwesterly flow in response to the ridge axis shifting
shifting east Friday along with surface low pressure transiting
the Upper Great Lakes yields an increasingly moist column late
Friday afternoon into Friday night. Precipitable water values
edge up toward 1.5 inches ahead of the approach of a cold front
associated with the aforementioned Great Lakes low Friday night.
Upper level support for this feature largely stays well to the
north allowing the front to wash out Friday night into Saturday.
This will also keep deep layer shear rather weak also yielding
relatively slow storm motions. Could potentially have some very
isolated water issues with multiple slow moving storms moving
over the same location, but given the state of vegetation and
recent dry conditions, concerns are relatively low.

The weak flow pattern persists through the weekend featuring mainly
diurnally driven convection.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
As of 108 AM Wednesday...

Widespread dense fog will allow for IFR/LIFR restrictions or
lower across the forecast area this morning as skies begin to
clear from west to east and winds decrease. Shortly after
sunrise, dense fog will start to lift and dissipate between
~12-13Z, subsequently giving way to VFR under mostly clear
skies. This will last through the day until another round of
river valley fog arrives overnight into Thursday.

Winds calm to light and variable this morning, becoming light
and SW`rly during the day.

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

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Timing and intensity of dense fog this
morning could vary. Low stratus could form across the higher
portions of the mountains instead of dense fog.

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                              WED 05/01/24
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  L    M    M    M    H    H    H    M    H    H    H    H
HTS CONSISTENCY  L    H    H    H    H    H    H    L    L    H    H    H
BKW CONSISTENCY  H    H    M    H    H    H    L    L    H    H    H    H
EKN CONSISTENCY  M    M    M    M    M    M    M    L    H    H    H    H
PKB CONSISTENCY  M    M    H    H    H    H    M    L    H    H    H    H
CKB CONSISTENCY  L    L    M    H    H    H    M    M    H    H    H    H

AFTER 06Z THURSDAY...
IFR conditions possible due to fog Thursday morning.

&&

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

&&

$$

SYNOPSIS...TRM/LTC
NEAR TERM...LTC
SHORT TERM...TRM
LONG TERM...JP
AVIATION...LTC