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000 
FXUS61 KRLX 232023
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
423 PM EDT Tue May 23 2017

.SYNOPSIS...
Upper level low digs into the Tennessee Valley and brings 
chances of showers tonight through Thursday. Unsettled again for
the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 235 PM Tuesday...

Digging upper level low over the Midwest is kicking out 
embedded waves in the cyclonic flow out ahead of it, the first 
of which arriving is responsible for an expanding precipitation 
shield now pushing across the Tug Fork Valley. So the coverage 
of rain will be on the increase through this evening, especially
over the Ohio Valley as the waves aloft push into the region. 
Really wanted to take the thunder out, but will allow the slight
chance of thunder through the evening even pushing the 
procedure with higher CAPE criteria to generate the areas of 
thunder. 

The upper closed low will continue to dig into the Tennessee,
while continuing to eject energy into the CWA. Should get a lull
later tonight, but ramp the POPs up fairly sharply heading into
Wednesday. The old day 2 rainfall forecasts from WPC puts the
mountains in a marginal risk for excessive tomorrow. For the
lowland areas, this should equate to a half inch to three
quarter inch even through 00Z Thursday, and possibly double 
that for the mountains. Not expecting water issues as of this
issuance, and no headlines in place.

Upper level low to keep the temperatures in check through the
near term, with lowland 50s tonight and around 70 to the lower
70s Wednesday.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 340 PM Tuesday...

Upper low over the Ohio Valley early this period gets kicked 
out by end of this period. Til then, upper disturbances swirling
around this upper low will bring likely chances for showers 
through the day Thursday. Temperatures will be cooling by 
Thursday as we get on the back side of the upper low itself, 
with temps slightly below normal for this time of year with all 
the clouds and showers. Instability looks very meager so no 
thunder included with the showers. 


&&

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

With the upper low having been kicked out by Friday and high 
pressure moving in, it looks to be dry Friday with some temperature
recovery under more sunshine. The flow aloft quickly becomes 
zonal by the weekend. We again return to unsettled conditions 
for the weekend as upper disturbances within this zonal flow act
on increasing moisture from the gulf of mexico on the back side
of the high pressure. Temperatures  will respond to slightly 
above normal levels. High pressure finally builds in for awhile
early next week.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
As of 125 PM Tuesday...

Have some wholesale changes in effect for the afternoon issuance
of the TAFs, primarily dealing with earlier arrival and longer 
duration of rain across the region thanks to an upper level wave
moving in from the southwest. Expect coverage to increase from 
development of showers as much as showers moving in. Biggest 
concern off the top is duration of the rain that can often times
lead to ceilings collapsing down to IFR, but have held this off
in the forecast until after 00Z and later, with the expectation
of convective rain keeping to lowest levels churned enough. 
Have quite a bit of IFR in the forecast however once this upper 
level wave exits, which could give the lesser seen IFR ceilings 
and visibilities as winds approach calm. The timing is tough as 
well.

Higher chances for showers return after 10Z Wednesday, but
southeast wind should help lift ceilings after sunrise.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
     
     
FORECAST CONFIDENCE: Low to medium. High confidence on rain
overall, but timing and subsequent conditions when periods of
rain end are tricky.

ALTERNATE SCENARIOS: Timing of rain could vary. May need to be
more aggressive with IFR or LIFR tonight. 

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

AFTER 18Z WEDNESDAY...
Upper level low keeps IFR chances in play through Thursday night.

&&

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

&&

$$
SYNOPSIS...JMV/26

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