Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 132352

Area Forecast Discussion
National Weather Service Louisville KY
752 PM EDT Fri Oct 13 2017

...Updated Aviation Discussion...

.Short Term...(This evening through Saturday night)
Issued at 232 PM EDT Thu Oct 13 2017

Skies have mostly cleared out this afternoon, with just a few clouds
showing up on satellite in the Bluegrass region. Temperatures have
climbed into the upper 60s to lower 70s. High pressure will remain
in place at the surface and aloft tonight. These will then begin to
shift eastward on Saturday as a trough and associated low pressure
system swing across the Plains and approach the forecast area on
Saturday night.

Dry and warming weather is expected through this time frame. For
tonight temperatures will fall into the 50s under the mostly clear
skies with light winds. Some patchy fog development is expected
again tonight. Once any fog dissipates Saturday, warm weather and
partly cloudy skies are in store with highs in the low 80s. Cloud
cover will be on the increase Friday night as the low pressure
system and its cold front approach. Southerly winds will keep
temperatures mild overnight, only dropping into the mid to upper 60s.

.Long Term...(Sunday through Friday)
Issued at 347 PM EDT Fri Oct 13 2017

The long term period will start out with a strong cold front just to
the west of our southern IN counties. This front will cross the
region through the day, making it to around the Ohio River by mid to
late morning and move off to the east by late afternoon or early
evening. Showers and thunderstorms will be ongoing along the front
Saturday night, but should be weakening by Sunday morning as the
front moves into the region. They will become more scattered in
nature across southern IN and areas along the Ohio River on Sunday
morning. Better coverage is then expected again in the afternoon
across east central KY. Soundings do show a bit of elevated
instability, so will keep the mention of isolated thunderstorms in
the forecast, but severe weather is not expected at this time.

Behind the front winds will become gusty with sustained winds out of
the west to northwest at 15-20 mph with gusts to 30 mph.
Temperatures will be tricky as much cooler air will be quickly
moving in behind the front. Temperatures will initially rise on
Sunday but will begin quickly falling again in the afternoon behind
the front. Lows Sunday night will drop into the 40s by daybreak.

Dry weather is expected through the remainder of the long term
period. The lowest temperatures of the period will be Monday and
Monday night with highs on Monday topping out in the low 60s and
lows Monday night dropping into the upper 30s to lower 40s. Some
isolated frost may be possible in sheltered locations. We will then
see a slow warming trend for the rest of the week back into the
low to mid 70s.


.Aviation...(00Z TAF Issuance)
Issued at 740 PM EDT Fri Oct 13 2017

The main TAF concern will be fog tonight as most models indicate a
good inversion setting up under sfc high pressure and ridging aloft.
Don`t think tonight will be as ideal for fog as last night due to
the high pressure/ridging drifting slightly to the ESE and slightly
drier sfc conditions. We may have a little more of a wind at the sfc
and aloft, but still on the lighter side.  Some of the hourly high
res guidance isn`t as aggressive with dense fog tonight as earlier
runs were. But the 18Z NAM soundings still show a very strong
inversion with moisture trapping and crossover temp analysis
supports IFR or lower fog.  So will keep the 0Z TAF forecast very
similar to the 18Z issuance with vsbys dropping around or shortly
after 6Z at the TAF sites.  IFR or lower fog should occur between 9-
13Z.  Fog will dissipate and vsbys improve shortly after sunrise
tomorrow morning.




Short Term...EER
Long Term...EER
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