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fxus63 kpah 221747 

Area forecast discussion
National Weather Service Paducah Kentucky
1247 PM CDT sun Oct 22 2017

issued at 1238 PM CDT sun Oct 22 2017

Updated for 18z aviation forecast discussion


Short term...(today through Tuesday night)
issued at 230 am CDT sun Oct 22 2017

At 07z, a cold front was draped from western Wisconsin through
central Missouri into central Texas. A line of convection, some severe,
is lined up along this front...not too far from our western

Our biggest challenge today will be figuring out pops and timing
of this front and its associated convection. Precipitation will
continue to enter our area throughout the morning hours and
impacting all of southeast MO, southern Illinois and far west KY,
leaving southwest in and the pennyrile region of west Kentucky mainly
dry. Model quantitative precipitation forecast depiction during the morning hours is not one that
would make ME think widespread convection everywhere as the wall
of rain to our west is progged to break up a bit as it heads east.
However, periods of on and off showers and maybe a few storms
look to be a pretty good bet across a good part of our area in
the morning.

The potential for showers and a few storms shifts east with time
during the afternoon today as the upper trough to our west moves
eastward. Models still are not in sync with timing however and
updates to the pop gradient and timing are going to inevitable
today as the day shift watches how the radar is trending. However,
the GFS seemed to have the best handle on timing early this
morning and followed it along with some of the cam model
suggestions for pops today.

As has been mentioned for several days now, plenty of moisture in
place throughout the atmosphere is resulting in high precipitable
waters and hence a good chance to see some heavier downpours here
and there. However, the severe weather aspect of this system
continues to look low.

During the evening hours, we will continue to see the west to east
progression of the showers. Exact timing is hard to pin down at this
point but areas of southeast MO should be drying out during the
evening hours, while the heavier quantitative precipitation forecast is expected over the eastern
half of the County Warning Area. Overnight tonight, we will be seeing more and more
of our western counties drying out as sfc high pressure tries to
start building in. A lot of tonight's forecast will revolve around
the behavior of an upper level low that is expected to develop
around 00z Monday in Arkansas or MO. The exact placement and movement of
this feature is tied to where the rain will be set up for the
evening/overnight hours, and unfortunately, even at this late stage,
models have differences. This will hopefully be ironed out with the
future models runs and be fined tuned later today.

The upper low moves east overnight and into the day on Monday which
should act to shove the precipitation further east during that time.
However, some models close off this low which ends up
complicating matters. Best chances for additional rain on Monday
still looks to be in our eastern counties with pops tapering off
quite a bit by Monday night.

Late Monday night into Tuesday, a large deep upper trough starts
to shift into the area from the northwest which will mark a pretty
substantial air mass change across the area. Moisture associated
with this trough might be enough to set off a few showers but
chances are too low to mention at this time. Highs on Tuesday will
struggle to get out of the mid to upper 50s. Lows Tuesday night
in the upper 30s will be conducive for some frost production as

Long term...(wednesday through saturday)
issued at 230 am CDT sun Oct 22 2017

High confidence in frontal passage Friday into Saturday. Medium
to low confidence in the exact timing.

Wednesday a surge of warm air will approach the area with a dry warm
front lifting through on Thursday. This will bring warmer
temperatures for Thursday...likely approaching 70 degrees. The
moisture however will be limited with dew points remaining in the
40s for most areas. Immediately in the warm fronts wake a fairly
strong cold front will be poised to move through Friday into
Saturday. The best chance of rain will come Friday as the cold front
makes its way through the area. Rain chances rapidly fall off as we
head through Saturday as do temperatures. We will be approaching the
freezing mark this weekend or Saturday night as winds slowly back
off. Right now models do not suggest thunder as there is low
instability at the surface and aloft. Pw's are not impressive either
since they never even reach one inch. So at this time severe weather
is not anticipated but will have watch for possible frost this
coming weekend.


issued at 1238 PM CDT sun Oct 22 2017

We will be dealing with scattered rain showers and isolated
thunderstorms, which will increase in coverage this afternoon and
evening, esp over wrn Kentucky/SW in/srn Illinois. South winds will gust into
the 20kts throughout the area during the day. Winds will
gradually shift around to the west and eventually northwest as the
front moves through from west to east late in the day and tonight.
However, a slow moving upper level system may end up causing rain
to linger into the morning hours over our eastern counties. In
addition, MVFR cigs are likely to develop with the heavier showers
and near and after frontal passage.


Pah watches/warnings/advisories...

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