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fxus63 kpah 222341 
afdpah

Area forecast discussion
National Weather Service Paducah Kentucky
641 PM CDT Thu Aug 22 2019

Update...
issued at 633 PM CDT Thu Aug 22 2019

For aviation section only.

&&

Short term...(tonight through Saturday night)
issued at 315 PM CDT Thu Aug 22 2019

Current convective line moving through west Kentucky should
continue to work southeast through the remainder of the afternoon.

The sub-synoptic setup for the evening and overnight convective
potential will be an interesting, given the proximity of the split
flow near the weather forecast office pah forecast area. From the north another minor
shortwave will rotate around the broad northeast U.S. Trough
through Missouri this afternoon and into this evening. From the
west and southwest, a minor trough will develop under the central
and northern plains mid-upper level ridge, where more zonal flow
is impacting the southern half of the U.S. The combination of
these features will enhance lift and generate another round of
convective activity over southeast Missouri and southwest Illinois
this evening. This feature will then move eastward into southwest
Indiana and the pennyrile region of west Kentucky overnight.

After this shortwave moves east of the area on Friday, the mean
frontal boundary will be shifted southward with some overrunning
north of the boundary, as high pressure from the north builds into
the area. The next shortwave trough behind the northern stream
ridge will move into the Central Plains Saturday into Sunday.
Given the proximity of the decayed frontal zone to the weather forecast office pah
forecast area, there is a small potential for convection over
southeast Missouri during the weekend. For now, have kept a small
mention for storms Friday over this area.

Long term...(sunday through thursday)
issued at 315 PM CDT Thu Aug 22 2019

The Central Plains shortwave will lift the boundary back to the
north on Sunday. As the northern stream shortwave (projected to be
in the middle Mississippi Valley on monday) moves east through the
weather forecast office pah forecast area on Monday into Tuesday, increased rain
chances across the area. In discussions with other forecasters,
the signal for this convective scenario has been consistent the
last few days.

The Fly in the ointment will be Wednesday into Thursday.
Numerical models have been inconsistent on the evolution of the
next northern stream trough moving south from Canada and the
interaction with southern/southwest U.S. Ridge/zonal flow. The nbm
(national blend of models) incorporated/blended the various model
solutions, keeping low pops in place for Wednesday and Thursday.
For now, have low confidence in rain chances for this time period,
but attempted to blend with surrounding National Weather Service offices for
collaboration purposes.

&&

Aviation...
issued at 640 PM CDT Thu Aug 22 2019

With a frontal boundary expected to effectively move south
towards the area later this evening and overnight, reduced
ceilings into the MVFR/IFR category, esp aft 06z through much of
Fri am. Though we are expecting isolated to scattered
thunderstorms tonight into Friday, the more precise timing of
precipitation in the taf's will be difficult at best. Thus, chose
not to include explicitly at this time. Most of the thunderstorm
activity, though sub severe, will contain very heavy downpours and
locally erratic and gusty winds.

&&

Pah watches/warnings/advisories...
Illinois...none.
MO...none.
In...none.
Kentucky...none.
&&

$$

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