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Area forecast discussion 
National Weather Service Charleston WV
809 PM EDT Wednesday Jul 27 2016

a weak east to west frontal boundary just to our north will
move little. Several disturbances and copious moisture will bring
heavy rainfall potential Thursday into Friday.


Near term /through Thursday/...
745 PM update...

One band of showers and storms currently over east Kentucky will shift into
S WV and SW Virginia over the next couple of hours while dissipating as
it does so. This disturbance passes to the east this evening while
the quasi zonal flow becomes more amplified and out of the SW
toward morning. This will allow a potent wave to track into the
area for Thursday along with copious amounts of moisture. There
still exists some discrepancy in the near term and short term
models regarding the heavies axis of qpf with this feature with
some taking it more into southeast Ohio and along the Ohio River and others
focused further southeast. Complicating matters is extent of convection
tomorrow which would enhance rainfall amounts. There should be
quite a bit of cloud cover to limit heating but with the tropical
atmosphere we are in it still looks like a general 1 to 2 inches
with isolate higher amounts possible along wherever the main qpf
axis sets up and in any convection. Flash Flood Watch will
continues as is.

Previous discussion below...

Broad and very moist upper level low over the southern
Mississippi Valley this afternoon...having pw's above 2
inches...will move northeast later tonight and Thursday. There is
model consensus of tracking the system across our area and
targeting our area with heavy rain potential Thursday...a general
1 to 2 inch swath with locally heavier amounts in any training of
storms. Enough instability available for thunderstorms despite
the expected cloud shield...but does not look like a severe
thunderstorm threat scenario at this time. Thus...with much of the
area nearly saturated from yesterday...have issued an flash Flood Advisory with
this system from 12z Thursday to 12z Friday for a good part of our
area. Have started conservatively...omitting parts of southeast
Ohio and far southeast portions of the area from the watch based
mainly on not receiving yesterdays rainfall. Otherwise any
convection this afternoon...mainly in the south...will wane fairly
early this evening with loss of heating. As the above mentioned
system approaches...there will be a large shield of clouds ahead
of it. Given that this system is very nearly tropical in probably will not be as dependent on solid diurnal
heating to generate convection as we are used to. Thus...more
confidence in issuing the flash Flood Advisory.

It will continue to be warm and muggy tonight with the high
dewpoints and increasing clods overnight. For Thursday...somewhat
cooler only because of the clouds and showers and storms...but
quite muggy. Highs in the lower to mid 80s.


Short term /Thursday night through Saturday/...
heavy rain threat to continue across the area Thursday night into
early upper shortwave trough and surface wave push east
through the cwa. Still model differences between exact timing and
track of these features...but overall...heaviest threat through
early Friday looks to be across northern/eastern zones. In addition
to heavy rain...a few storms Thursday night could be on the stronger
side...with 30-40kts shear and decent cape...the potential for
strong storms...with damaging winds a primary threat exists. The
Flash Flood Watch for the period will be in effect until 12z Friday.

Additional showers and thunderstorms are possible later in the day
Friday and Saturday...particularly across the north in the vicinity
of stalled frontal multiple upper disturbances cross
the region. There will still be a threat for heavy downpours with
any convection...and with an overall light flow...localized flash
flooding may continue to be a concern.


Long term /Saturday night through Wednesday/...
weather looks to remain unsettled for most of the extended period as
additional disturbances move through the region. Drier weather
possible early to mid next week as upper ridging strengthens across
the region. Another front late week.


Aviation /00z Thursday through Monday/...
sct shra/tsra across S WV thru 02z with localized IFR
conditions...primarily S of khts/kcrw...otherwise VFR conditions

After 02z...initially sct-bkn 5000-7000 feet above ground level with loss of
convection...then increasing clouds from the southwest. Becoming
ceilings 5000-7000 feet 09z-12z with scattered showers redeveloping
over the south by 12z. Overnight fog also redevelops after 05z
tonight with localized IFR/LIFR River Valley fog expected...mainly
north...and especially if clouds are slower to increase. Kbkw is
expected to experience IFR/LIFR fog first this evening /around
03z/ as they received rainfall earlier.

After 12z Thursday...organized shield of showers and storms
spreading northeast across the area with conditions lowering to
MVFR/IFR especially in convection.

Confidence and alternate scenarios...

Forecast confidence and alternate scenarios through 00z Friday...

Forecast confidence: medium.

Alternate scenarios: fog potential tonight depends greatly on
cloud coverage.

Experimental table of flight category objectively shows consistency
of weather forecast office 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 Thursday 07/28/16
UTC 1hrly 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1hrly 20 21 22 23 00 01 02 03 04 05 06 07
crw consistency h h h h h M M M M M M M
heights consistency h h h h h h M M M M M h
bkw consistency h h h h h h h h h h h h
ekn consistency h h h h h M M l l l l l
pkb consistency h h h h h h M M l l l l
ckb consistency h h h h h h M M l l l l

After 00z Friday...
IFR conditions in showers and thunderstorms through Thursday


Rlx watches/warnings/advisories...
WV...Flash Flood Watch from Thursday morning through Friday morning
for wvz005>009-013>020-024>032-036>040-046-047.
Ohio...Flash Flood Watch from Thursday morning through Friday morning
for ohz083-085>087.
Kentucky...Flash Flood Watch from Thursday morning through Friday morning
for kyz101>103-105.


near term...jmv/30

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