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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 302336
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
736 PM EDT Fri Oct 30 2020

.SYNOPSIS...
High pressure crosses tonight and Saturday. A strong cold front
crosses Sunday to bring an early winter chill on Monday. High
pressure with moderating temperatures the balance of the week.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 730 PM Friday...

Moisture fetch off the Upper Great Lakes continues to weaken at
this hour with stratocumulus beginning to dissipate. Confined
morning fog coverage to the most protected river bottoms with
2-5KT boundary layer flow persisting even in the early morning
hours. May need to cut this back even further and potentially
revisit morning lows depending on clearing trends over the next
few hours.

As of 450 PM Friday...

Adjusted hourly temperatures down slightly initially based on
observed trends. Flattened the late evening cooling curve a
little based on a little more persistent stratocumulus than
previously forecast. Also expanded showers originating from a
moisture fetch off the Upper Great Lakes a bit further back to
the west from the higher terrain. Overall, previous forecast was
in good shape.

As of 210 PM Friday...

Amid low level northwest flow, showers were concentrated over
the most favored upslope areas in north-central WV. Snow mixed
in over the very highest terrain may give a thin coating before
ending this evening, as high pressure cuts off the upslope flow.

High pressure will lead to clear, calm conditions overnight
tonight, conducive to river valley fog, as well as frost, and
near to below freezing temperatures. The frost/freeze program,
however, is over.

Return dry downslope southeast flow around the back side of
exciting high pressure will lead to abundant sunshine on
Saturday, along with a milder afternoon.

Central guidance temperatures looked on or close, with little
change from the previous forcast.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 230 PM Friday...

High pressure moves off to the east allowing a stacked low
pressure system associated with an upper level trough to
traverse towards the area during Sunday morning. This feature
will drag in a cold front which will provide some precipitation
and CAA for Sunday. By early Monday morning, northwesterly flow
on the backside of the front will induce upslope showers across
the higher elevations, while CAA will help temperatures sink
even further.

Below freezing temperatures across the entire area is expected with
possible teens in the highest peaks and ridges. With moisture still
in place on Monday morning, due to wrap around flow, moisture
will nudge into the dendritic growth zone in the higher
terrain. Any showers should then turn into snow which has the
potential to accumulate in the northeast mountains.

With blustery winds as frontal passage takes place gusts up to
30KT are possible with slightly more intense gusts in the
mountains which will cause wind chills to drop near 0F in the
higher terrain. Accumulations may have difficulty on the ground
with strong wind, however up to 1-2 inches should come to
fruition by early Monday afternoon in certain areas until
finally a high pressure ridge builds in to cut off moisture and
convince accumulations to conclude.

Winds relax by the late afternoon on Monday and high pressure
dominates thereafter. With a very cold start to Monday, quite
the opposite occurs through the rest of the week as a very
subtle warming trend takes hold in the long term.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 230 PM Friday...

A very benign weather pattern will set in during the long term
period with high pressure steadily protecting the area with
more seasonable daytime highs and cold overnight lows due to
optimal radiational cooling nights. Long range models do diverge
towards the end of this period while handling an upper level
feature that will provide a possibility of showers across the
mountains for the weekend, however they do agree the area will
remain dry during this period.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 730 PM Friday...

Stratocumulus ceilings 025-040 will slowly dissipate overnight
yielding mainly clear skies by early Saturday morning. This should
allow for at least areas of river valley fog near all the terminals
except BKW. Boundary layer flow of 2 to 5 KTs coupled with a
relatively late clearing of clouds will likely restrict significant
visibility reductions to the most protected river bottoms and may
limit how much fog can make it onto the terminals. For now have just
included only patchy fog at PKB/HTS where confidence is lower
with a couple hours of VLIFR fog near daybreak for CRW/CKB/EKN.
May need to trim this back even further with the 03Z/06Z
issuance depending on clearing trends.

Aside from any morning fog issues, mainly clear skies prevail for
the remainder of the day Saturday with winds switching around to the
south 5-10KTs.

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

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Fog may remain largely confined to river
bottoms with minimal terminal impacts Saturday morning.

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       22   23   00   01   02   03   04   05   06   07   08   09
EDT 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    L
HTS CONSISTENCY  H    H    M    H    H    H    H    H    H    H    H    M
BKW CONSISTENCY  H    H    H    H    M    M    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    H    H    H    H    H    M    M    H    L
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 00Z SUNDAY...
No widespread IFR conditions expected at this time.

&&

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

&&

$$
SYNOPSIS...TRM/JZ
NEAR TERM...TRM/JP
SHORT TERM...JZ
LONG TERM...JZ
AVIATION...JP