Area Forecast Discussion
Issued by NWS Charleston, WV

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
409
FXUS61 KRLX 261738
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
138 PM EDT Fri May 26 2017

.SYNOPSIS...
High pressure will bring a brief reprieve of dry, warmer
weather today. Disturbances along a wavering front will bring
showers and thunderstorms over the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 940 AM Friday...

No changes this morning.

As of 210 AM Friday...

Finally a break in the weather expected today. Upper low
continuing to move off to the east, as high pressure nudges into
the region. Much of the area will still be under quite a bit of
cloud cover this morning, but expect a general improvement as
the day progresses. Gusty west-northwesterly winds will continue
through much of the afternoon behind departing low.

Clouds will gradually increase later this evening and overnight.
A warm frontal boundary and upper disturbance will move into the
region late tonight/early Saturday, kicking off showers and
isolated thunderstorms again, becoming more numerous later in
the day Saturday.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
As of 5 AM Friday...

A roughly west-northwest to east-southeast oriented front,
roughly parallel to the upper level flow, will oscillate about
the area Saturday into Sunday, modulated on the mesoscale by
thunderstorm complexes that are likely to form along or near it.
This begins with a modest 25 kts h85 LLJ Saturday morning along
a theta e axis in which h85 dew points climb from 12 to 15C.

Deep layer bulk shear as high as 50 kts Saturday morning
decreases to 40 kts south and only 20 kts north Saturday
afternoon, while CAPE increase to near 3 kj/kg south and
central portions of the area Saturday afternoon, so southern to
perhaps central portions of the area appear favored for the
strongest thunderstorm development Saturday afternoon and
evening.

Depending upon how the convection evolves Saturday into
Saturday night, cool pooling could effectively push the
boundary south Saturday night, setting up another warm
advection feed Sunday morning. The h85 is progged to peak near
35 kts overnight Saturday night, before decreasing again, but
bulk shear is forecast to increase to over 50 kts again
overnight Saturday night and continue through Sunday, while
CAPE forecast values vary among models but are forecast to be
highest west.

Upper level ridging crosses Saturday night, switching the upper
level flow from west-northwest Saturday to west-southwest on
Sunday, with embedded short wave troughs tied to convective
mesoscale complexes, but with a general tendency to push the
front northeastward into Sunday night.

Will maintain heavy rain and strong thunderstorm wording in HWO
and state briefing, but, in collaboration with neighboring
offices, will wait until we get a little closer to convective
development to begin timing and placement of any needed flash
flood watches.

A cold front crosses overnight Sunday night, leading to a drier
weather pattern to start the new work week.

The mesoscale dominated pattern is likely to result in variation
from central guidance temperatures with time, which show small
diurnal ranges not far from normal on average.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 5 AM Friday...

A weak cold front crosses Tuesday beneath upper level northwest
flow, with surface high pressure and upper level ridging
remaining well out to the west. The high does pass south of the
area on Wednesday, and another upper level short wave trough is
progged to drive a new surface cold front into the area
Wednesday night and Thursday. It may taken the better part of
Friday to push that front through the area.

Central guidance temperatures accepted, largely near normal.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
As of 125 PM Friday...

VFR through the afternoon with wind gusts 20-25kts and cumulus
above 4kft.

Complex of storms moves in from the west northwest after 05Z
Saturday, and will likely be on the slow wane. However, TSRA and
IFR visibilities are likely at PKB and CKB, but carry only SHRA
into EKN by the time it reaches that terminal. The southern
sites of HTS, CRW, and BKW will likely be on the fringe of this
activity, so some restrictions may have to be added here with a
track that goes a bit further to the south.

All models are holding strong on decreasing ceiling heights
into the late morning hours, so carry MVFR during this time.
Cold front drops south, so the bulk of the afternoon convection
should be relegated south of PKB-CKB-EKN. That said, leaving low
chances for convection across the north.

Forecast Confidence: High through 06Z. Medium after.

ALTERNATE SCENARIOS: Convection timing tonight could vary by an
hour or two. Thunder chances may need to be added or eliminated
across northern terminals..


EXPERIMENTAL TABLE OF FLIGHT CATEGORY NOT AVAILABLE

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.

Table unavailable at this time.

AFTER 18Z SATURDAY...
IFR likely in showers and storms Saturday night and Sunday.


&&

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

&&

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.