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FXUS63 KLMK 112236

Area Forecast Discussion
National Weather Service Louisville KY
536 PM EST Wed Dec 11 2019

...Updated Aviation Discussion...

.Short Term...(This evening through Thursday)
Issued at 250 PM EST Wed Dec 11 2019

Sfc high pressure will remain in control of the region tonight 
allowing for dry conditions and mostly clear skies.  Winds will 
become light and vrb overnight.  This will allow for good cooling 
with lows expected in low to mid 20s.

For Thursday, sfc high pressure will slowly move to the east.  A 
light return flow will commence Thu afternoon and an upper level 
trough will approach the Ohio Valley from the west.  As we remain in 
between weather systems, the airmass will modify with highs in the 
40s to around 50 expected Thu.

.Long Term...(Thursday night through Wednesday)
Issued at 320 PM EST Wed Dec 11 2019

Thursday night - Saturday

Thursday night an uneventful shortwave will move west to east 
through the County Warning Area (CWA). This will be followed by an 
upper trough advancing east from the Plains. This trough should make 
it to the Mississippi River Valley by Friday afternoon. Gulf 
moisture will be funneled north and isentropically lifted ahead of 
the trough. Still thinking the precipitation will fall as rain and 
areas east of Interstate 65 will likely be the affected area. Expect 
this rain to end Friday night. 

Heading into Saturday afternoon/evening, another shortwave will push 
through with the axis of the upper trough. This won't produce much 
in the way of precipitation, but a flurry or spitting spinkles are 

Sunday night - Tuesday morning

An upper trough surges south of the Four Corners region as Gulf 
moisture gets pushed north along the Mississippi Valley between the 
surface low forming over Texas and high pressure over the 
southeastern CONUS. As the trough pushes the surface low east, the 
low deepens and warm and cold fronts form. The warm front extends 
east of the low and will work its way north through the Ohio Valley 
on Monday. Shortly after this, the cold front extending south of the 
low will move east over the Ohio Valley quickly Monday night. 

The moisture is there with the fronts. Precipitation will fall. The 
last few runs of the GFS has kept the low running through relatively 
the same area (Indiana). Some runs of the Euro place the low 
farther north near central Tennessee. If the low goes farther 
south, it means cooler temperatures for the CWA, which means more 
snow. If the low goes further north, warmer temperatures and more 
rain with some severe weather possible. 

Current thinking favors rain over snow. A mix and periods of snow 
are possible at times, but at this time, not expecting a major snow 
event. Windy conditions appear to be very likely with this system.


.Aviation...(00Z TAF Issuance)
Issued at 536 PM EST Wed Dec 11 2019

High pressure over West Virginia will provide us with clear skies 
and light winds tonight. On Thursday that high will head to Cape 
Cod, resulting in breezes under 10kt coming in from the southeast 
and cirrus increasing high overhead.




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