Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 181053
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
653 AM EDT Fri Aug 18 2017

.Short Term (Now through Saturday)...
Issued at 255 AM EDT Fri Aug 18 2017

A cold front approaching the Ohio River before dawn will cross
central Kentucky this morning and usher drier air into the region
this afternoon. After some morning clouds we should see plenty of
sunshine this afternoon with temperatures rising into the mid 80s to
around 90. Dew points, however, will be 10 to 15 degrees lower than
yesterday resulting in lower humidity values.

Weak surface ridging will build in from the lower Mississippi Valley
this afternoon and tonight with mostly clear skies and nighttime
lows in the 60s. Some patchy valley fog can be expected around dawn
Saturday in the Lake Cumberland region.

Saturday surface low pressure beneath an upper shortwave trough will
move from Indiana to Ohio with a cold front trailing behind it. Most
of the moisture associated with this system will be between 700 and
500hPa, with drier low levels and precipitable water values only in
the 1.25-1.50" range. As a result, precipitation chances will be
low. The best shot at a shower or thunderstorm will be over southern
Indiana and the northern Blue Grass closer to the low. High
temperatures will be in the middle and upper 80s.

.Long Term (Saturday Night through Thursday)...
Issued at 305 AM EDT Fri Aug 18 2017

Saturday Night through Sunday Night...

Ridging will build in at the surface and aloft over the southeast
United States, resulting in dry weather and typically warm
summertime temperatures.

Eclipse Day...

Upper ridging will remain in place, but the surface high will begin
to shift to the east. The GFS and GEFS have really dried out, while
the EPS still supports isolated convection, as does the fact that we
could get into some return flow as the surface high edges away. So,
while a stray pop-up thundershower can`t be entirely ruled out, for
the most part it looks like an otherwise dry day with partly cloudy
skies.

High temperatures Monday afternoon will be a few degrees either side
of 90 with dew points around 70 west of I-65. Heat index values will
rise into the middle 90s...possibly briefly in the upper 90s in a
few spots...during the afternoon.

Tuesday-Thursday...

A cold front will sweep through the region from northwest to
southeast Tuesday and Wednesday, accompanied by showers and
thunderstorms. Pacific high pressure will then come in with dry
conditions Wednesday night and Thursday. Heat index values should
again climb into at least the middle and possibly upper 90s Tuesday
afternoon, but then cooler conditions can be expected Wednesday and
especially Thursday.

&&

.Aviation...(12Z TAF Issuance)
Issued at 653 AM EDT Fri Aug 18 2017

Last of pre-cold front showers still in the vicinity of KLEX at
1030Z, but these should be east of the terminal by valid time of the
12Z TAFs. As the front pushes through this morning, winds will swing
around to WNW and increase to 7-8kts, while low clouds scatter out,
leaving only cirrus behind.

Some fog possible late in the forecast period, otherwise CAVU with
winds dipping to variable under 3 kts by 00Z.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&

$$

Short Term........13
Long Term.........13
Aviation...JBS


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