Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 181945
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
345 PM EDT Fri May 18 2018

.SYNOPSIS...
Surface wave exits tonight. Upper system crosses this weekend.
Weak disturbances cross early next week. Cold front crosses mid
week, followed by high pressure to end the work week.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 120 PM Friday...

The muggy, unsettled pattern continues in the near term period.
Upper low continues to linger across the Mississippi Valley
region today, with multiple disturbances crossing through the
region, and a good moisture fetch from the south. Still looking
like best chances for thunderstorms will be across the western
2/3 of the CWA where better instability will lie, but an
isolated thunder threat cant be completely ruled out area wide.

Models are pretty consistent in indicating an uptick in the
precipitation tonight, particularly across northeastern zones,
as a shortwave moves through the region. Did elect to extend the
flood watch across the north by a few hours tonight to cover
this period, although think overall threat will remain fairly
low. Southern half of flood watch should be able to expire as
planned this evening, if not be dropped early.

Low will open into a wave later this evening, with upper
shortwave trough moving east across the area on Saturday, with
increased chances for showers and thunderstorms, some of which
could produce strong wind gusts, although overall threat looks
low. SPC has placed much of the CWA in a marginal risk for
Saturday. Storms should move well tomorrow, thereby decreasing
threats for flooding, but localized issues wont be completely
out of the question, particularly if an area sees multiple
rounds.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 345 PM Friday...

Models are slower with an upper level short wave trough, that
may now take until Sunday to exit completely out of the area. As
such, showers and thunderstorms remain likely well into the
night Saturday night, with the chance going into Sunday, mainly
across eastern portions of the forecast area.

0-6 km bulk shear remains progged for Saturday evening in the
mountains, to go with 1000-1500 J/Kg, and SPC maintained the
marginal risk. Stability increases quickly in the evening, with
some indication of a cool pool over WV suggestive of a bowing
line of convection ahead of it, and a bowing line of storms has
sometimes panned out in the past when this signature was shown
in the past.

The forecast for Sunday night through Monday night depends
largely upon where a surface front associated with the weekend
short wave ends up. Models diverge here on whether the front
meanders over the area, keeping the weather unsettled, or sets
up mostly north of the area for less unsettled, but warmer and
more humid weather.

Central guidance keeps temperatures above normal, with mid 80s
by day and mid 60s by night across much of the lowlands.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 345 PM Friday...

Models are a little later with a cold front crossing mid week,
so the weather may remain unsettled into Wednesday. An upper
level short wave trough pushes the cold front through Tuesday
night or early Wednesday while phasing into a long wave trough,
that sets up over the Canadian / New England Maritimes as a long
wave ridge sets up over the upper midwest. This should set us
up with drier weather later next week, with slightly lower
temperatures and dew points, but still above normal on the
former /and probably the latter/.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
As of 130 PM Friday...

Rounds of showers and thunderstorms for the TAF period, with
periods of MVFR and IFR in precipitation. Most of the area will
remain VFR today outside of showers/storms, however, higher
terrain locations, such as BKW may remain MVFR or even develop
IFR conditions late tonight in southeast upslope flow, and
continued rounds of precipitation. In addition, a period of
heavier precipitation is possible particularly after 02Z across
northeastern WV, affecting sites KEKN and KCKB, creating
MVFR/IFR conditions.

Showers and thunderstorms will increase in coverage again after
15Z Saturday.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY...

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: More widespread IFR conditions may occur
tonight in precipitation, particularly across the northeast,
than currently forecast.


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       18   19   20   21   22   23   00   01   02   03   04   05
EDT 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
HTS CONSISTENCY  L    L    H    M    H    H    H    H    H    H    H    M
BKW CONSISTENCY  M    H    H    M    M    M    M    M    M    M    M    L
EKN CONSISTENCY  M    H    L    L    L    L    L    L    L    L    M    L
PKB CONSISTENCY  H    H    M    H    H    H    H    H    H    H    H    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M

AFTER 18Z SATURDAY...
Brief periods of IFR possible in showers and storms into the
weekend and again for the beginning of the work week.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Flood Watch through late tonight for WVZ028-030>032-039-040-
     521>526.
     Flood Watch until 9 PM EDT this evening for WVZ033-034-515>520.
OH...None.
KY...None.
VA...None.

&&

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



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