Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 170706
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
306 AM EDT Thu May 17 2018

.SYNOPSIS...
Unsettled weather pattern continues into the weekend with daily
shower and thunderstorm chances in a warm and humid air mass.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 250 AM Thursday...

Upper level low anchored over the mid Mississippi/lower Ohio
Valleys will continue the south to north push of upper level
disturbances with a tropical moisture feed. Meanwhile, a weak
stationary boundary over the mountains will slowly drift
southward just south of the CWA tonight. The mountains will once
again be the target for more persistent showers and a few storms
through the near term period, and will continue the flash flood
watch for this area with no changes. Keeping thunder at a
minimum overall again, but should not be ruled out. The
construction of the POP grids is largely based on trying to
chase small low/mid level deformation zones. Again, this mimics
more of a mid/late summer pattern than mid spring, especially
given the lack of any appreciable flow aloft.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
As of 300 AM Thursday...

An upper level low and multiple waves moving around it will
bring widespread showers and storms Friday. GFS and NAM hinting
at the dry slot moving through Friday night, so have lower POPs,
but not a completely dry forecast. During this time the upper
low is gradually filling and by Saturday passes as a weakening
trough. This should still bring a resurgence in POPs Saturday
with activity tapering off Saturday night as the trough moves
away. Still have a lingering surface boundary in the vicinity,
so again did not go completely dry across the forecast area
Saturday night and Sunday.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
as of 300 AM Thursday...

Expect a surface boundary to start out just south and east of
the forecast area Sunday night. This will push north as a warm
front in response to a surface low crossing the mid to upper
Mississippi River Valley. GFS and ECMWF differ in the path of
this so kept POPs just under likely levels for now. Lower
confidence remains through the end of the period as the GFS
keeps us in a more active zone with a surface boundary across
the forecast area while the ECMWF is more progressive driving
the front south. Used a consensus blend to amount for this
uncertainty.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
As of 200 AM Thursday...

Rapid fog development is possible in terminals that clear thru
12Z.

Lowland terminals catch a break from the rain chances thru 16Z.

Expect rain coverage to increase again throughout the period in
SHRA, but largely without TSRA or VCTS/CB. Thunder is not
completely out of the question, and a brief TEMPO may need to be
added here and there, but these will primarily be more tropical
showers. Expect brief IFR in these, but cannot use for
prevailing for the most part with this issuance, except for
prolonged rain forecast for the mountains after 20Z.

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

FORECAST CONFIDENCE: Low to Medium.

ALTERNATE SCENARIOS: Timing of showers and thunderstorms could
vary thru the whole period. Timing, location, and density of
fog/ceilings overnight could vary.


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                              THU 05/17/18
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    M    M    M    M    M    H    H    H    H    L
HTS CONSISTENCY  M    L    L    L    M    L    M    H    H    H    H    M
BKW CONSISTENCY  M    M    M    L    L    L    L    L    M    M    M    L
EKN CONSISTENCY  L    L    L    L    L    L    L    L    M    M    M    L
PKB CONSISTENCY  M    M    L    L    L    M    L    H    H    M    H    M
CKB CONSISTENCY  M    M    L    L    L    L    M    M    M    M    M    L

AFTER 06Z FRIDAY...
Brief periods of IFR possible in showers and storms into the
weekend.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Flood Watch through Friday evening for WVZ028-030>034-039-040-
     515>526.
OH...None.
KY...None.
VA...None.

&&

$$
SYNOPSIS...MZ/26
NEAR TERM...26
SHORT TERM...MZ
LONG TERM...MZ
AVIATION...26



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