Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 181439
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
939 AM EST Sat Jan 18 2020

.Forecast Update...
Issued at 938 AM EST Sat Jan 18 2020

Numerous light to moderate showers continue to move east across the
region this morning ahead of a cold front. This rain is on track on
wind down fairly quickly from west to east this afternoon.

There has been an uptick in the winds this morning with frequent
gusts in the 30-40 mph range. A low-level inversion and plenty of
clouds/precip are significantly limiting mixing, which will keep
much stronger winds aloft. However, the strongest winds are expected
to peak between now and early to mid afternoon. The Simpson Co KY
Mesonet station recently gusted to 41 mph, so think we`ll see
additional 40+ mph gusts through the late morning and early
afternoon hours.

&&

.Short Term...(Today and tonight)
Issued at 310 AM EST Sat Jan 18 2020

...Windy, Rainy, then COLD...

Today we`ll be in the warm sector of an intensifying storm system
that will affect much of the country from the Plains to the
Appalachians. Strengthening low pressure will advance from Wisconsin
to Michigan with a cold front trailing southward. Strong southerly
flow will draw moisture northward resulting in a low gray overcast
and widespread rain. We won`t be able to realize much mixing today,
but with 60-70kt winds 2-3k` off the surface, wind gusts to advisory
criteria could be realized, especially this morning before the
overnight low level jet begins to weaken and shift off to the east.

Temperatures today will peak in the 50s; rainfall amounts should
generally be in the 1/3-1/2 inch range.

The cold front will barge through the Ohio Valley late this
afternoon and early this evening, bringing and end to the rain but
also ushering in much colder air ahead of a strong ridge of high
pressure over the Prairie Provinces and Great Plains. By Sunday
morning readings will have fallen into the teens in southern Indiana
and the low to mid 20s in central Kentucky. Winds will stay up in
the 10 to 20 mph range through the night. Though that will hopefully
be beneficial in drying off area roadways to prevent moisture from
the daytime rainfall from turning to ice tonight, we will have to
deal with wind chills dipping into the single digits in southern
Indiana and the 10-15 degree range in central Kentucky.

.Long Term...(Sunday through Friday)
Issued at 312 AM EST Sun Jan 12 2020

We will begin the long term in a western ridge/eastern trough
pattern aloft, with an area of surface high pressure slowly gliding
southeastward from the northern Plains to the Ohio Valley by Tuesday
afternoon. After a mild start to the new year, much colder
temperatures are in store for the beginning of the week as the
Canadian high continues to spread Arctic air across the central
CONUS. While the average temperature at each of our climate sites
has run about 12 degrees above normal for January so far, expect
temperatures to drop to 10-15 degrees below normal for the start of
the week. High temperatures Sunday and Monday will fail to reach
above freezing for much of the area, with temps topping out in the
mid 20s to lower 30s both days. Low temperatures will be in the mid
teens to low 20s Monday morning, with wind chills expected to dip
into the low teens to single digits.

By Wednesday, expect temperatures to begin warming back up into the
mid to upper 40s as the high pressure pushes off to the east and
surface winds veer to the south. Temperatures will continue to warm
into the 50s for the end of the week, with low temperatures in the
mid to upper 30s.

Our next chance for measurable precipitation will come late Thursday
and into Saturday as an upper level trough pushes across the central
Plains. However, a lot of uncertainty remains with this system as
models continue to disagree on overall timing and location of the
upper trough and associated surface low. Overall, the best chances
for rain look to be during the day Friday, with rain exiting to the
east by Saturday morning.

&&

.Aviation...(12Z TAF Issuance)
Issued at 608 AM EST Sat Jan 18 2020

During the early morning hours a very strong low level jet will
develop over the lower Ohio Valley ahead of a strengthening Midwest
storm system. This will bring warm air northward above the surface
resulting in an impressive inversion, and necessitating in LLWS in
the TAFs for a few hours.

Winds will continue to be a significant issue during the day today
as the synoptic scale system continues to strengthen with the parent
low advancing from Iowa to Michigan and our TAF sites in the windy
warm sector. Gusts over 30kt can be expected, coming in from the
south ahead of the cold front.

Cold FROPA is expected this afternoon/evening, shifting winds to the
west. Gusty west winds will continue through tonight.

Rain will be widespread ahead of the front today, with sub-fuel
alternate ceilings as moisture flows northward into the region.
Behind the front low level moisture will manifest into low ceilings
at HNB/SDF/LEX, but BWG may be far enough south to break into clear
skies after midnight.


&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...Wind Advisory until 3 PM EST this afternoon for INZ091-092.

     Wind Advisory until 1 PM EST this afternoon for INZ090.

KY...Wind Advisory until 3 PM EST /2 PM CST/ this afternoon for
     KYZ028>043-045>049-053>057-063>067-074>077-081.

     Wind Advisory until 1 PM EST /noon CST/ this afternoon for
     KYZ024-025-027-061-062-070>073.

&&

$$

Update...EBW
Short Term...13
Long Term...JML
Aviation...13



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