Area Forecast Discussion
Issued by NWS Charleston, WV

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249
FXUS61 KRLX 202327
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
727 PM EDT Sun Aug 20 2017

.SYNOPSIS...
High pressure through Tuesday. Strong cold front late
Tuesday/Tuesday night. Cooler and drier for the end of the week.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 725 PM Sunday...

Only minimal changes made to previous forecast to better reflect
current obs and trends.

As of 120 PM Sunday...

Weak high pressure keeps the CWA dry and warm today. A minor
impulse at 500 mb passes to our north overnight though trended
towards SREF and GFS ensembles keeping the forecast dry. There
should be fog again in the river valleys overnight though the
impulse and a full day of sun today may lessen the density and
extent overnight. Despite this, still kept a general mention of
fog in the river valleys.

Monday high pressure holds on albeit weakly, but should be
enough to keep us dry again with minimal cloud cover except in
the mountains where daytime heating may be enough to spark a few
isolated showers.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 230 PM Sunday...

5h trough digs southeast into the Great Lakes with an
accompanying front at the surface. This feature will drive a
colder airmass of continental Canadian air into the eastern US
by Wednesday night. Have front pegged to be along the Ohio River
along the WV-OH border at around 06Z Wednesday and this feature
will drive shower and isolated thunderstorm activity across the
forecast area with decent wetting rains. Made some adjustments
to the model blend pops by just a few hours but generally
accepting guidance.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 230 PM Sunday...

Cool period in the long term as Canadian airmass in control of
our sensible weather. Surface high dominates the eastern
seaboard. Used guidance throughout the period.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
As of 725 PM Sunday...

Expecting dense river valley fog to form again tonight, however
with an upper level impulse passing just north of the forecast
area there is a potential for some clouds playing havoc with fog
formation. This impulse may also keep some flow going...again
having an adverse affect on fog formation.

Fog will dissipate quickly after sunrise with VFR through the
remainder of the TAF period. An isolated shower is possible
across the northern mountains counties monday afternoon.

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

FORECAST CONFIDENCE: High, except low to medium with fog.

ALTERNATE SCENARIOS: Timing and density of fog may vary based on
clouds and some remaining flow.

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    M    L    L
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    L    L
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M
EKN CONSISTENCY  H    H    H    H    H    H    H    H    M    L    L    M
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    M    L    L
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    L

AFTER 00Z TUESDAY...
Dense river valley fog possible each morning.

&&

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

&&

$$
SYNOPSIS...KMC/JW
NEAR TERM...JW/MZ
SHORT TERM...KMC
LONG TERM...KMC
AVIATION...MZ



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