Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 292001
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
401 PM EDT Mon May 29 2017

.SHORT TERM...(This evening through Tuesday night)
Issued at 359 PM EDT MON MAY 29 2017

Cyclonic flow will rule across the Ohio and Tennessee Valley
regions through the short term, as an upper level low currently
positioned across southern Ontario, lifts north and deepens as
additional short wave energy moves in from north central Canada.

One cold front has settled off to our southeast today, with a
passing upper level jet streak providing enough lift to allow for
some thicker higher clouds to linger across our area. There is
also some afternoon cumulus in the mix, with clouds expected to
dissipate into this evening with the loss of heating and the exit
of the upper level jet streak. Lows will range from 55 to 60
degrees, with some patchy fog possible in the deeper river
valleys.

The next cold front will drop down and move through eastern
Kentucky on Tuesday, sparking a few showers and storms, especially
in the far southeast. Highs will be in the upper 70s to around 80
degrees. POPs will subside into Tuesday evening, before increasing
once again towards dawn Wednesday morning, as another cold front
approaches from the northwest. Lows Tuesday night will be in the
mid to upper 50s.

.LONG TERM...(Wednesday through Monday)
Issued at 401 PM EDT MON MAY 29 2017

A cold front will progress SE to begin the forecast period. This
will be the focal point for showers and thunderstorms through the
afternoon on Wednesday. Some of these storms could be strong
particularly in the SE portions of the CWA where MUCAPE climbs
into the 1000 J/kg or higher and effective shear will climb into
the 30 to 40 knot range. This will lead to isolated severe threat
with strong winds and small hail being the main threat
particularly as freezing levels drop below 10 KFT. This boundary
will drop SE and high pressure will build into the region in the
wake. This will provide a nice break for Thursday before return
flow and short waves bring precipitation chances back up by
Friday.

A more defined surface boundary will slowly work south as we move
into the weekend. Given the flow parallel to the boundary, deep
warm layer and PWATS above 1.5 will lead to potential for heavy
rain event. There however remains some question in the evolution
of the synoptics and this is still leading to some uncertainty on
the extent of the heavy rain threat. The 12Z GFS and 00Z ECMWF
were in good agreement in the pattern, but the 12Z ECMWF now leans
toward the previously outlier Canadian. That said leaned toward
the 12Z GFS and 00Z ECMWF for the forecast at this point. Given
this did lean toward a dry period from Sunday night into Monday,
as an area of high pressure builds SE behind the frontal boundary.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 236 PM EDT MON MAY 29 2017

Expect mainly VFR conditions through the period. Scattered to
broken stratocu ranging from 3-5k feet agl will gradually
dissipate by this evening. Thicker mid and high level clouds
should also thin into tonight, before additional moisture advects
in out ahead of the next approaching cold front on Tuesday. Some
patchy fog may also develop late tonight, mainly affecting the
deeper valleys. A few showers will accompany the frontal passage
on Tuesday, with south to southwest winds at around 5 kts, becoming
more westerly at 5 to 10 kts towards the end of the period.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...GEOGERIAN
LONG TERM...DJ
AVIATION...GEOGERIAN


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