Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 281118

Area Forecast Discussion
National Weather Service Louisville KY
618 AM EST SAT NOV 28 2015

...Updated Aviation Discussion...

.SHORT TERM (Now through Sunday)...
Issued at 255 AM EST Sat Nov 28 2015

A weakening cold front will sink slowly southward across Kentucky
during the weekend, continuing to act as a focus for rain. We can
lower the PoPs some in southern Indiana tonight and Sunday as the
plume of rich 1.5-1.75 PWAT air streams mainly over the
Commonwealth. Weekend rainfall amounts in southern Indiana should be
in the 0.6-0.8 inch range, and in Kentucky around an inch.

This evening, models are showing deep saturation and a sharp
inversion just a few hundred feet off the surface. MOS is suggesting
fog across northern central Kentucky, in an area of nearly calm
surface winds associated with the weak, broad frontal zone. Will put
some patchy fog in the grids to account for this possibility.

Temperatures will be very tricky to figure out today given the
clouds, unevenly distributed rain, and sagging front. Will go for
lower and middle 50s north of the Ohio River to middle 60s in
southern Kentucky.

Lows tonight will mostly be in the 40s, though southern Kentucky
will probably not drop further than the lower 50s. Depending on how
low the temperature at Bowling Green gets before midnight tonight,
and in any heavier patches of rain today, the daily record warm
minimum of 54 degrees set in 1934 may be in jeopardy.

Cool air coming in behind the front will restrict highs to the 50s
on Sunday...maybe even just upper 40s in southern Indiana and the
northern Blue Grass.

.LONG TERM (Sunday night through Friday)...
Issued at 308 AM EST Sat Nov 28 2015

The upper low that has been over the Intermountain West will finally
begin to head east at the start of the long term, crossing the
Midwest Tuesday and the Great Lakes Wednesday. It`s corresponding
surface low will move slightly ahead of the upper low Monday and
Monday night, pulling a warm front north through the Tennessee and
Ohio Valleys, followed by its attendant cold front swinging through
the region Tuesday as the system becomes stacked over the Lakes. As
a result, showers will continue to be in the forecast Monday-
Tuesday. Strong winds aloft will accompany the cold fropa Tuesday,
and models are beginning to show a little bit of instability just
ahead of the front. However the instability still looks weak enough
to leave thunder out of the forecast for now. The Lake Cumberland
region and the southern Blue Grass stand the best shot at a rumble
or two.

Winds will be somewhat gusty on Tuesday as the front moves through,
and gustier still on Wednesday in a tight gradient between the low
to our north and high pressure over the Plains.

That high, of Pacific origin, will provide us with dry weather for
the second half of the work week. Morning bus stop temperatures
really won`t be too bad for December, right around freezing. Highs
will be around 50...which is just about normal.


.AVIATION (12Z TAF Update)...
Updated at 615 AM EST Sat Nov 28 2015

Although all TAF sites remain at VFR conditions this morning,
conditions will slowly deteriorate throughout the day. METARs reveal
IFR/LIFR conditions right behind an approaching cold front.  The
front will make slow progress SE over KY over the next 24 hrs.  By
15-20Z expect VFR with occasional dips into the MVFR cat.  By 17Z,
SDF should go solidly into the IFR cat with BWG/LEX following closer
to 20Z.  Delayed the timing of MVFR/IFR conditions in the TAFs as
models have proven to be too quick with the front speed and flight
restrictions. The front will finally get through SDF by around 21z
and BWG/LEX by 0-2Z. Behind the front expect at least IFR conditions
and probably dropping to LIFR or lower.  Since this is nearing the
end of the TAF period, will keep things optimistic with IFR for
tonight. Also with the fropa expect a wind shift from SSW to WNW.
Light rain is expected to continue on and off throughout the entire
TAF period possibly becoming more of a light drizzle late tonight.


.LMK Watches/Warnings/Advisories...


Short Term........13
Long Term.........13
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