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Area forecast discussion 
National Weather Service Jackson Kentucky
328 PM EDT Tuesday Jul 26 2016

Short term...(this evening through Wednesday night)
issued at 328 PM EDT Tuesday Jul 26 2016

The frontal boundary stalled along the Ohio River will remain the
primary feature of concern through tomorrow. Storms along this
boundary early this afternoon are showing signs of organization as
they track eastward. This cluster of storms is expected to track
across The Gateway region of northeast Kentucky later this
afternoon with outflows probably generating additional scattered
showers/storms further to the south. Pwats are analyzed above 2
inches across our northern counties, and are near record highs
according to latest mesoscale precip discussion from wpc. Thus
these storms will produce torrential rainfall and any training of
cells will pose a threat for isolated flash flooding. A severe
storm or two is possible, mainly over our northern counties, with
damaging winds the primary severe weather hazard.

Convection should exhibit a strong diurnal trend again and
diminish quickly after sunset before firing up again with daytime
heating tomorrow afternoon. Models want to nudge the front a
little to the south by tomorrow so anticipate scattered storms
developing over our area, instead of to our north as has happened
today. Another warm and muggy day is anticipated tomorrow with
highs in the upper 80s to near 90 and afternoon heat indices 95 to
100.

A shortwave will track northeast out of the western Gulf on
Wednesday forcing a wave of low pressure to develop on the front
to our southwest. This will move into western Tennessee late
Wednesday night and bring a slug of Gulf moisture northeastward
into central and eastern Kentucky forcing an increase in showers
and storms by late Wednesday night.

Long term...(thursday through tuesday)
issued at 328 PM EDT Tuesday Jul 26 2016

Unsettled weather will continue through the forecast period as upper
level troughiness remains over eastern Kentucky. The operational GFS
and European model (ecmwf) are in good agreement aloft with this overall pattern. The
main concern during the long term is the potential phasing of
northern and southern stream waves Thursday into Friday. The initial
wave from the Mississippi Valley is progged to lift northeast
through our area Thursday, followed shortly by the northern stream
wave from the Great Lakes. The GFS model is slightly quicker and
stronger with these waves and tries to phase them as they move
through the area. This system looks to exit Kentucky late Friday
but a series of upper level waves passing by will keep
precipitation chances in the forecast through the remainder of the
period.

At the surface, there will be daily chances for showers and
thunderstorms. The best chance for substantial rainfall will be
Thursday into Friday as a surface low, coinciding with the passing
of the previously mentioned upper level waves, moves across our
area. Model soundings on Thursday are skinny and saturated from the
surface up through the upper levels, with precipitable waters nearing 2.3 inches.
This would be a record value for our area, per iln climatology.
These types of soundings are indicative of heavy rain producers and
flash flooding. Additionally, winds through the profile are
unidirectional, with training of showers and thunderstorms a decent
possibility. There is also potential for some of the storms to
become strong with cape values in excess of 2k. That being said,
rain and thunderstorms will be possible with this system beginning
Thursday morning and continuing into Friday evening. Saturday
through Tuesday, shower and thunderstorm activity should be limited
to the afternoon and evening hours each day.

Afternoon temperatures throughout the long term will generally
remain in the low to mid 80s thanks to afternoon shower chances each
day. Expect morning lows near climatological normals, in the mid and
upper 60s.

&&

Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 128 PM EDT Tuesday Jul 26 2016

A stationary frontal boundary remains located along the Ohio
River with eastern Kentucky remaining in a steamy and unstable
airmass. Scattered thunderstorms are again expected to develop
this afternoon and diminish during the evening with fog developing
tonight into Wednesday morning at locations that get hit by
storms. Exact details at taf sites are hard to pin down due to
the hit and miss nature of the expected storms so indicated thunderstorms in the vicinity
into the early evening hours and then a tempo period of at least
IFR conditions in fog/stratus at all taf sites. I did pinpoint sym
and sjs with a more pessimistic LIFR period with sym being more
likely to see a storm this afternoon and sjs likely to get fog
development building over from the Big Sandy Valley. A repeat
performance is then expected for Wednesday.

&&

Jkl watches/warnings/advisories...
none.
&&

$$

Short term...Abe
long term...jvm
aviation...Abe

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