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FXUS63 KLMK 051708

Area Forecast Discussion
National Weather Service Louisville KY
1208 PM EST Thu Dec 5 2019

...Updated Aviation Discussion...

.Forecast Update...
Updated at 1001 AM EST Thu Dec 5 2019

Morning satellite imagery shows mostly clear skies across southern 
IN and central KY.  Temperatures have warmed into the upper 30s to 
the lower 40s as of 10 AM.  Current temperature forecast for the 
afternoon of low-mid 50s over southern IN and the northern half of 
KY still look on track.  Upper 50s to near 60 will be possible along 
and south of the Cumberland Parkway region.  Current forecast is in 
good shape and no update will be required at this time.  However, 
will do a quick data load in the very near term to bring initialized 
forecast close to current conditions.


.Short Term...(Today through Friday) 
Issued at 230 AM EST Thu Dec 5 2019

Surface high pressure centered over the Gulf states will be ushered 
gradually eastward throughout the day today by a shortwave 
originating out of the Four Corners. Mostly sunny skies for much of 
the day coupled with southerly winds will allow afternoon max temps 
to reach into the low to mid 50s across southern Indiana and central 
Kentucky and close to 60 across south central Kentucky. 

Increasing mid and high clouds will occur this evening ahead of an 
approaching cold front, while light rain chances will enter into our 
western counties by early Friday morning and continue to spread 
eastward across the entire CWA by late morning. Thermal profiles 
indicate that this will be entirely a light rain event, ending in 
our eastern and southern counties by Friday evening. Southerly flow 
and cloud cover will keep Friday morning temps in the low 40s with 
highs expected in the upper 40s in the north and increasing toward 
the low to mid 50s in our south.

.Long Term...(Friday night through Wednesday)
Issued at 231 AM EST Thu Dec 5 2019

Friday night - Saturday night... 

High pressure over the upper Midwest ridging southward to the Gulf 
Coast at the beginning of the long term period will head east to New 
England. This will keep us dry with seasonable temperatures.

Sunday - Tuesday...

A deep upper trough over the Canadian Archipelago at the start of 
the long term will dive south into the United States east of the 
Rockies. At the surface a cold front will charge southeastward out 
of the Prairie Provinces across the Plains and Midwest, and then 
through the Ohio Valley Monday night. Widespread showers will break 
out ahead of this system, with a few thunderstorms possible just 
ahead of the front Monday evening. Dry air in the 700-500mb layer 
may help to keep rainfall amounts in check. Right now the forecast 
calls for amounts on the order of half an inch to an inch with the 
higher amounts in southern Kentucky. Temperatures will be pleasant 
for early December, with highs on Monday in southwest flow ahead of 
the front reaching the upper 50s and lower 60s.

Behind the front cold air will rush in as the moisture and 
precipitation move out. As of now it doesn't appear that significant 
snow is likely given that drier air will move in quickly behind the 
front. Still, it's something to keep an eye on over the coming days.

Tuesday night - Wednesday...

Strong Arctic high pressure will invade the northern Plains and Ohio 
Valley with cold, dry air. Lows Tuesday night will be in the upper 
teens to lower 20s. Southern Indiana will likely stay below freezing 
on Wednesday.


.Aviation...(18Z TAF Issuance)
Issued at 1208 PM EST Thu Dec 5 2019

For the afternoon and evening, VFR conditions are expected at the 
terminals.  Winds will be light and variable but then start to pick 
up out of the south by this evening and into the overnight period. A 
cold front will approach from the west late tonight bringing mid-
high level cloudiness into the region with showers developing in the 
west as early as 06/06-08Z at KBWG/KHNB, and then in the 06/09-12Z 
at KSDF and KLEX.  VFR cigs/vsbys are expected for much of the 
overnight, but latest guidance supports ceilings dropping to fuel-
alternate cigs by 06/12Z with MVFR vsbys due to light rainfall.  The 
outlook for the daylight hours on Friday is for cigs running in the 
FL015-025 range with 4-5 miles of vsbys due to rain showers.

Forecast Confidence Intervals:

This afternoon/eve: High on Cigs/Vsbys
Late Tonight/Friday: Moderate-High on Cigs, Moderate on Vsbys.




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