999
FXUS61 KRLX 052330
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
730 PM EDT Sat Oct 5 2024

.SYNOPSIS...
High pressure maintains dry weather through Sunday morning. A
cold front brings showers and storms Sunday evening. Dry for the
remainder of the week.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 725 PM Saturday...

Previous forecast remains on track. No changes needed.

As of 200 PM Saturday...

High pressure north of the area today slides east tonight and
Sunday, allowing northeast low level flow to veer to southeast
overnight tonight, and then south to southwest on Sunday. This
may make for differences in timing and location of dense River
fog overnight tonight and early Sunday morning, but overall, it
appears most likely in and near the mountains but out to the
Charleston area as well. A slightly tighter pressure gradient
over the middle Ohio Valley should limit the potential for dense
River Valley fog there.

Otherwise, there is nary a cloud in the forecast, as a
mid/upper-level ridge crosses, until Sunday afternoon, when the
ridge gives way to an approaching mid/upper-level short wave
trough and surface cold front. The south to southwesterly flow
between the exiting high and approaching cold front will sponsor
a warmer and somewhat more humid afternoon.

A mid/upper-level low moves eastward across southern Canada,
just north of the U.S. border and Great Lakes, through Sunday.
While the low maintains steady intensity or even fills a bit
during this time, it does push the southern edge of the
westerlies at the trough axis farther south with time.

Dew points rise into the lower to mid 60s in an axis ahead of
the cold front Sunday afternoon, but only along and west of the
Ohio River, where CAPE could build to over a KJ/kg coincident
with 0-6 and 0-8 km bulk shear of 35-45 kts, highest north. DESI
CAPE probabilities collapse above a KJ/kg while DESI 0-6 km
bulk shear probabilities collapse above 30 kts.

With flow veering slightly with height, cells in a broken line
of showers and thunderstorms just ahead of the approaching cold
front could become strong to even marginally severe, with
possible wind damage, marginally severe hail, and just enough
CAPE amid the cooling mid level air for marginally severe hail.
These severe threats would be mainly in southeast Ohio late
Sunday afternoon.

Guidance suggests just as cool a night tonight as recent
nights, which is a little above normal for early October, and
then a warmer Sunday afternoon, about 10 degrees above normal,
with clouds limited to the west and late, ahead of the
approaching front.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
As of 210 PM Saturday...

The on-going line of showers and thunderstorms quickly progresses
southeast across the area Sunday night with severe potential
diminishing as they progress. Cool northwest flow over the Great
Lakes will likely yield some stratocumulus ceilings for Monday
morning into Monday afternoon with highs struggling to get out of
the 60s amid cool advection.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 210 PM Saturday...

Westerly flow aloft persists as surface high pressure builds from
the Mid-West into the Northeast through the week. Daytime highs will
be near normal values for this time of the year, with morning lows
below normal for this time of the year. Little in the way of
impactful weather is expected with this pattern with the exception
of:

Frost/Freeze:

Mountain valleys will begin to pickup increased potential for frost
beginning Monday night and persisting through the week. By Thursday
and Friday sufficient low level dry air is expected to be in place
for cold air drainage to support some freeze potential in these
valleys with frost spreading out into the lower elevations. The
mountains will be will within their interquartile climatological
range for first freeze, so any freezes here would likely end the
frost/freeze program for this growing season.

Morning valley fog:

With still quite warm rivers, overnight lows in the 30s/40s should
prompt strong moisture flux off the warm water. Cold air drainage
into the valleys will also contribute to morning fog development.

Renewed dryness:

With foliage beginning to thin out, even across the lower
elevations, the forest floor will becoming increasingly
susceptible to drying out on full sunshine days. With recent
rainfall and fine fuel recovery, this will be a slow uptick in
any potential fire danger.

&&

.AVIATION /23Z SATURDAY THROUGH THURSDAY/...
As of 720 PM Saturday...

VFR conditions under clear skies will prevail tonight, expect
for IFR/LIFR conditions due to river valley fog during the
predawn hours Sunday morning. Terminals most likely to be
affected by dense fog will be EKN, CRW, and PKB. EKN could fog
from 05Z through 13Z. A morning surprise is expected at CRW and
PKB with dense fog developing from 10-12Z Sunday morning.

A cold front is progged to cross the area from west to east
Sunday evening, perhaps bringing a wind shift at PKB around 00Z
Monday. This cold front will move quickly east affecting mostly
the northern sites such as CKB and EKN Sunday evening. Brief
periods of IFR conditions can be expected along the heaviest
rainfall.

Winds will remain calm tonight, becoming light from the
southwest on Sunday afternoon. Winds will shift from the
northwest behind the cold front Sunday evening. Light winds
aloft increasing from the west at 25 knots on Sunday, remaining
strong from the northwest behind the cold front.


FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY...

FORECAST CONFIDENCE: High.

ALTERNATE SCENARIOS: Fog overnight tonight may form earlier than
forecast, or at sites not forecast for.

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       21   22   23   00   01   02   03   04   05   06   07   08
EDT 1HRLY       17   18   19   20   21   22   23   00   01   02   03   04
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    M    L    L
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 00Z MONDAY...
Showers/storms late Sunday evening into Sunday night could
result in brief IFR conditions, especially north. IFR in river
valley fog possible Tuesday and Wednesday mornings.

&&

.CLIMATE...

September 2024 - Warm Amid a Wide Range in Precipitation Totals

Compared to the 1991-2020 U.S. Climate Normals, it was a warm
September across the vast majority of the forecast area, with
mean temperatures for much of the area ending up 1 to 4 degrees
(Fahrenheit) above normal, with a few locations trending closer
to normal. In terms of precipitation, the first two-thirds of
the month was extremely dry across much of the forecast area, so
much so that some locations were on pace to potentially near
the mark for their driest September on record. For instance,
Charleston, WV had only received 0.09 inches of precipitation
through the 22nd of September! This quickly changed, however, in
the last third of the month given that it was quite wet,
particularly across southwest VA, southern WV and extending
northeast along the mountains, as well as in northeast KY and
far southern OH. Multiple rounds of rain would affect the forecast
area during this timeframe, with the most significant event
being associated with the remnants of Hurricane Helene and a
corresponding Predecessor Rain Event (PRE) in advance of the
main circulation, with the greatest impacts occurring across the
aforementioned areas. Given such, total precipitation for the
month of September varied significantly across the forecast
area, ranging from less than 2 inches across some locations in
the central/northern portion of the CWA (equating to departures
of 1 to 2 inches), while totals of 4 to 8 inches were observed
along the periphery of this region and also across all of the
southern portion of the CWA, with greater than 10 inches observed
at some locations in southwest VA. This equated to surpluses of
2 to 7 inches for the month in portions of the aforementioned
areas. For the sake of comparison, Charleston, WV only received
1.84 inches of precipitation throughout September, while one of
our Cooperative Observer Program (COOP) locations in southwest
VA (located just southeast of Nora in Dickenson County) only
about 100 miles to the southwest received 10.29 inches, which is
nearly 7 inches above what is normal there for September!

No top 10s were set at any of the official NWS RLX climate locations
this September in terms of mean temperature or total precipitation.

&&

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

&&

$$

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

CLIMATE...GW