Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 190522
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
122 AM EDT Thu Oct 19 2017

.Forecast Update...
Issued at 927 PM EDT Wed Oct 18 2017

Skies are clear once again this evening with light and variable to
calm winds across the region. Temperatures are in the 50s in most
locations with a few of the cold spots already into the upper 40s.
The forecast looks in good shape tonight with lows in the 40s and
some fog expected in the river valleys again. No major changes made
this evening.

&&

.Short Term...(This evening through Thursday night)
Issued at 215 PM EDT Wed Oct 18 2017

Clear skies and seasonable temperatures prevailed across southern
Indiana and central Kentucky as of early afternoon. A surface high
centered over West Virginia continued to bring very pleasant autumn
conditions to the lower Ohio Valley.

In the short term, not much in the way of weather concerns as the
surface high will continue to remain over the mid-Atlantic while an
upper ridge builds over the southeast US. This will bring moderating
temperatures each day through the remainder of the work week. Plan
on high in the 70s and morning lows in the 40s to 50s. Mostly clear
to clear skies should prevail each day along with light breezes out
of the southeast to south.

Expect another round of river valley fog tonight, though the winds
just off the surface will be noticeably higher, so this may preclude
dense and/or prolonged river fog from forming. Went ahead and
included patchy fog in the main river channels.

.Long Term...(Friday through Wednesday)
Issued at 215 PM EDT Wed Oct 18 2017

Saturday will continue to feature dry weather as the surface high
pressure begins to move off the east coast. A shortwave trough and
surface front will push into the central Plains. Expect breezier
conditions Saturday ahead of that feature along with slightly warmer
temperatures in the mid to upper 70s.

On Sunday, the shortwave trough and front will begin to push into
the lower Ohio Valley, especially late in the day toward the
overnight hours. Chances for showers and thunderstorms will spread
west to east as the day progresses. There continues to be some
uncertainty with the overall evolution in the synoptic features
between each model cycle, but 50 to 60 percent chances look
reasonable at this point.

Shower chances continue Monday depending on how progressive the
trough becomes, or if cuts off somewhere over the southeast US. The
18.12z guidance was in better agreement showing a very strong
longwave trough developing across the Great Lakes and east coast
which would send much cooler air into the region along with chances
for showers. Leaned on a model consensus which trends highs down
into the low 60s to even 50s with lows well into the 30s for most of
the area.

&&

.Aviation...(06Z TAF Issuance)
Issued at 105 AM EDT Thu Oct 19 2017

High pressure to our south and east will remain in control through
the valid TAF period. Main challenge will be fog potential at BWG,
which finally truly decoupled within the last hour. Should be able
to cross over Wed afternoon dewpoints, so will include at least a
TEMPO for IFR vis around daybreak. Farther away from the surface
ridge, the remaining sites still have larger temp/dewpoint spreads,
and flags on taller flagpoles suggest there is still some boundary-
layer mixing, so we`ll stay VFR.

SW winds during the day will remain near 10 kt, with little or no
cloud cover. Winds decouple again around sunset, and the next
issuance may need to address fog potential toward daybreak Fri.

&&

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

$$

Update...EER
Short Term...ZT
Long Term...ZT
Aviation...RAS


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