Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 170659
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
259 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 FRIDAY NIGHT/...
As of 405 PM Wednesday...

Split flow aloft with northern stream trough over the Great
Lakes and southern stream trough stretching across the
southeastern United States. Southern stream trough transitions
northward with trough axis making its way to the Tennessee and
Kentucky late Friday night. Atmospheric column quite moist with
PW values running around 1.75 inches. Moist atmosphere with weak
flow regime could lead to prolonged heavy rain events from slow
moving showers were any convective development occurs. Mass
fields of models are in fairly decent agreement in weak flow
regime with differences cropping up when getting down to the
finer details of the myriad of weak shortwaves embedded within
the flow. Thus leaned heavily on blends for the forecast. Flood
watch posted through Friday.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 405 PM Wednesday...

Pattern shifts out of split flow regime as 5h ridge strengthens
off the east coast. The upper level low shifts northeast and
departs on Saturday with a brief break before the next wave
arrives Sunday night into Monday. Blends give low end pops
through mid week and this looks reasonable based on model
trends.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
As of 750 PM Wednesday...

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...KMC/26
NEAR TERM...26
SHORT TERM...KMC
LONG TERM...KMC
AVIATION...26



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