Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 200523

Area Forecast Discussion
National Weather Service Louisville KY
123 AM EDT Fri Oct 20 2017

...Updated Aviation Discussion...

.Forecast Update...
Issued at 925 PM EDT Thu Oct 19 2017

Temperatures are generally in the 50s this evening across the region
with a few locations still in the low 60s. The only concern
overnight remains the chance for some patchy fog across the region,
particularly in river valleys. Just minor tweaks were made to
the forecast tonight with regards to fog location and hourly temps.


.Short Term...(This evening through Friday night)
Issued at 215 PM EDT Thu Oct 19 2017

Clear skies and seasonable temperatures prevailed across the lower
Ohio Valley thanks to high pressure centered over the lower

For this evening, plan on pleasant temperatures dropping into the
60s then overnight readings falling into the upper 40 to lower 50s.
An uptick in low-level moisture combined with much lighter winds and
clear skies could lead to patchy fog across the area, especially in
the favored river valley locations.

Pleasant autumn weather will persist through Saturday as an upper
ridge and surface high dominate the weather over the area. Plan on
highs to be in the 70s and lows in the 50s.

.Long Term...(Saturday through Thursday)
Issued at 215 PM EDT Thu Oct 19 2017

A slow moving shortwave will approach the area on Sunday and Sunday
night, though there remains some uncertainties in the evolution of
the synoptic features. The 19.12z guidance continues to advertise
that a cut-off low will develop over the southern US, gulf coast
region. There remains some questions on location and speed on that
feature and how much moisture is lifted north into our region.
Leaned on the model consensus which has increasing precipitation
chances Sunday with the highest chances /50 to 70 percent/ Sunday
night into Monday.

Models then do become in better agreement showing a deepening
longwave trough over the central and eastern US bringing much colder
air into the region. Highs will trend below normal with highs on
Wednesday in the lower to middle 50s.


.Aviation...(06Z TAF Issuance)
Issued at 122 AM EDT Fri Oct 20 2017

Decent setup for fog at all four TAF sites this morning, but some
variation is likely in how low everyone goes in terms of vsby.
Compared to previous nights, a bit more low-level moisture exists
in addition to very light winds at the surface and aloft. LIFR
conditions are most likely at BWG, possibly impacting LEX as well.
A period of MVFR fog is forecast for SDF/HNB, with some IFR mixed
in after 09z.

Once fog burns off shortly after sunrise, the rest of the day will
be VFR with mostly sunny skies. Scattered cirrus will begin
spreading in from the west this afternoon and evening. Winds will
remain light or calm early this morning, increasing to 5-7 kts out
of the SE during the day.




Short Term...ZT
Long Term...ZT
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