Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 201500
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1000 AM EST Mon Feb 20 2017

...Forecast Update...
Issued at 949 AM EST Mon Feb 20 2017

Recent visible satellite imagery shows some fog still across the
area, especially along river valleys and bodies of water, mainly
over southern Indiana and north central Kentucky. While some patchy
dense fog continues in places, most areas have seen much improved
visibility so will the let the advisory expire normally at 15z and
cover the patchy dense fog for some areas with a SPS.

Issued at 838 AM EST Mon Feb 20 2017

Area webcams and observations indicate 1/4 mile visibility or less
continuing across portions of southern Indiana and north central
Kentucky and the Bluegrass as of 830 am. Soundings show that in the
next hour or so mixing should win out and the fog should burn off.
Helping as well is a stream of cirrus moving overhead from the west.

In coordination with JKL/ILN/IND will extend the advisory through
15z /10 am EST/ for portions of the area, and will let the southwest
counties /Bowling Green area/ go at 14z /9 am EST/ where the
greatest improvement has been.

Issued at 624 AM EST Mon Feb 20 2017

Widespread dense fog continues across the region this morning and is
still expected to cause issues for the morning commute. However,
there is some improvement just to the west as Owensboro and
Greenville KY airports, along with Huntingburg, IN are now reporting
1-3 mile visibility. Some higher visibilities are beginning to show
up across east central KY as well. The Dense Fog Advisory looks good
as is and no changes are planned this morning.

.Short Term (Now through Tuesday)...
Issued at 255 AM EST Mon Feb 20 2017

The immediate concern for the short term period is of course the
dense fog. The dense fog has become particularly widespread along
and north of the Ohio River. Further to the south, it looks a bit
patchier, but there is still a good amount of fog. Webcams show
quite a bit of fog in BWG and the Glasgow ob has recently dropped
under a mile, so the Dense Fog Advisory will be expanded to these
two counties. Otherwise, webcams across the other counties near the
TN border do not look too bad right now, so will continue with just
an SPS. However, another expansion to the Advisory cannot be
completely ruled out. In the areas with dense fog, the morning
commute will certainly  be negatively affected.

Fog will start to mix out after sunrise, and will likely start from
the south. Soundings do indicate that mixing should occur more
quickly than it did yesterday. Most of it should mix out by mid to
late morning. After clearing, temps will rise quickly into the 60s
and low 70s.

Southerly winds and increasing cloud cover will keep temperatures
much warmer tonight with lows only dipping into the lower to mid
50s. A shortwave and weak cold front will approach the region early
Tuesday morning. A few showers may move into southern IN before
sunrise, but most of the scattered showers are expected on Tuesday
as the trough swings through. Highs on Tuesday will be a bit cooler,
but still in the mid to upper 60s.

.Long Term (Tuesday Night through Sunday)...
Issued at 307 AM EST Mon Feb 20 2017

Light rain will continue Tuesday night from the shortwave crossing
the area. A few showers may linger into Wednesday morning across
southeast portions of central KY, but should move out by mid day.

There will be a chance for rain and possibly a few thunderstorms on
Thursday as another weak disturbance moves through. However, the
trend from this set of model runs is drier, so confidence on these
showers is a bit lower than previously.

For Friday into Friday night, the models continue to be in pretty
good agreement with a strong low pressure system moving out of the
Midwest and across the Great Lakes region. The latest runs have
slowed down the development of showers and storms just a bit, with
the best coverage now looking to be in the afternoon and evening on
Friday. This would allow more heating during the day. Soundings
continue to show 500-1000 J/kg CAPE and an impressive wind field.
Strong to severe storms still look to be a possibility, so this is a
system to keep an eye on this week.

Much colder air will build in behind the front for the weekend.
Highs will top out in the upper 40s to mid 50s with lows back into
the 30s. The next chance for rain looks to be Monday as another low
pressure system moves northeast out of the Plains. This system will
also bring a bit of a warm up early next work week.

&&

.Aviation (12Z TAF Update)...
Issued at 613 AM EST Mon Feb 20 2017

Dense fog will significantly impact the terminals during the first
few hours of the TAF period this morning.  The fog is expected to
lift and mix out through the morning hours.  Current thinking is
that it will be around 20/14-15Z before things clear out completely.
After that, skies will be VFR with just some high cirrus filtering
in from the west. Surface winds will remain light and variable.

&&

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

&&

$$

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


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