Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 200547
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
147 AM EDT SAT AUG 20 2016

.SYNOPSIS...
Warm, very humid air through Saturday. Cold front Saturday night
into Sunday. Cool canadian high pressure then takes hold for the
early and middle part of next week. Cold front late in the week.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
As of 910 PM Friday...

Will update the chances of precipitation this evening based on the
latest radar trends.


As of 245 pm Friday...

The better flow for convective development lies over the southern
tier of counties through this evening...but mid and high level
moisture is keeping that in check for right now. Still think the
coverage of the showers will increase...but maybe not with as much
thunder as activity further north in clearer conditions. Still
operating in a high moisture content environment...tapped from the
western Gulf of Mexico...although PWAT values are closer to the
1.6 inch range as opposed to over 2.0 inches...which is pinned
further south over the Tennessee Valley. Regardless...downpours
are possible in the slow moving cells...although areal coverage of
the cells is on the smaller side.

As mentioned in the earlier aviation discussion...some uncertainty
tonight lies with the valley fog/stratus potential. Also...have
left slight chance POPs in overnight

No significant changes to the temperatures...with upper 60s/mid
80s in the lowlands and lower 60s/mid 70s for the mountains.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH MONDAY NIGHT/...
As of 345 pm Friday...
Breaking news... this discussion does not talk about very warm,
muggy air sticking around.

A cold front approaching Saturday night, and then crossing Sunday
morning, will eradicate the muggies Sunday afternoon. While the
flow strengthens ahead of the front, the time of night, and the
best forcing progged to shoot up through the upper Ohio valley,
this mid to late August front does not appear to pose much of a
strong nor heavy thunderstorm threat. Do have high likely pops
moving across ahead of the front overnight Saturday night and
Sunday morning.

Low cloud immediately behind the front Sunday morning should mix
out Sunday afternoon as the drier air behind the front moves in.
There may be stratus in the mountains early Monday morning on weak
upslope flow, and valley fog across the lowlands where the
gradient and flow slacken. Otherwise plenty of sunshine is on tap
for Monday with some cu. Monday night looks to be clear and calm
with valley fog as fog season is underway.

Temperatures may be somewhat non-diurnal Saturday night and Sunday
with the clouds, precipitation and passage of the front. Lowered
lows for Monday morning with the MET being lower than the MAV for
a change, otherwise no major changes to temperatures. Lowered dew
points a bit quicker behind the front Sunday afternoon and night.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 345 pm Friday...
High pressure brings a cooler, less humid reprieve for the first
half of the extended period, Tuesday and Wednesday. While low
level moisture may start to return northward on the backside of
the exiting high Wednesday, the weather will remain dry until
Thursday, when another cold front approaches from the west.

The onset of the precipitation looks to be a bit fuzzy at this
distance, with the chance gradually increasing Thursday and
Thursday night, a part of the forecast that will likely need fine
tuned with time. Friday carries the best chance for showers and
thunderstorms associated with this front, with the front itself
progged to cross Friday night.

Temperatures were close to a blend of the MEX, blended and central
guidance with no major changes.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
As of 145 AM Saturday...

Still a question of valley fog versus stratus overnight tonight.
Looking like LIFR stratus is starting to develop across the higher
terrain...and this may affect sites such as kbkw and possibly
kekn. Elsewhere...still expecting fog to initially form...followed
by stratus deck that raises visibilities...but creates widespread
mvfr conditions. Confidence is low.

Generally expecting conditions to improve to VFR after
14-16Z...with light southwesterly surface winds. In addition...sct
showers and thunderstorms will develop...generally from west to
east...mainly after 18Z as a cold front approaches the region...with
widespread mvfr and ifr cigs developing after 02Z.

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

FORECAST CONFIDENCE: Medium

ALTERNATE SCENARIOS: Stratus may or may not form, effecting density
of the fog overnight.

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                              SAT 08/20/16
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    L    L    L    M    M    M    M    H    M    H    M
HTS CONSISTENCY  L    L    L    M    L    L    M    M    M    H    M    L
BKW CONSISTENCY  H    L    L    M    M    M    M    M    M    M    M    L
EKN CONSISTENCY  L    L    L    L    L    L    L    M    M    M    M    L
PKB CONSISTENCY  L    L    M    M    L    L    L    L    M    M    H    M
CKB CONSISTENCY  L    L    M    M    M    M    L    M    H    M    M    M

AFTER 06Z SUNDAY...
IFR stratus possible Sunday morning...with fog possible most
mornings early next week.

&&

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

&&

$$
SYNOPSIS...TRM/26
NEAR TERM...RPY
SHORT TERM...TRM
LONG TERM...TRM
AVIATION...SL



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