008 
FXUS63 KLMK 180540
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1240 AM EST Tue Feb 18 2020

...Updated Aviation Discussion...

.Forecast Update...
Issued at 836 PM EST Mon Feb 17 2020

Wind gusts of 30-35 mph have been reported recently in middle 
Tennessee and extreme southern Kentucky as low pressure over Iowa 
lifts a warm front northward across the Commonwealth. Have upped 
wind gusts in the forecast for the next several hours to account for 
this. Wind gusts should settle down some during the pre-dawn hours 
late tonight as low level jetting moves off to the northeast.

&&

.Short Term...(This evening through Tuesday)
Issued at 250 PM EST Mon Feb 17 2020

After a fairly dry and quiet day across the region, rain chances 
will begin to increase tonight ahead of an approaching system. 
Regional radars have shown some light returns throughout the day, 
but for the most part, these rains have stayed to our north and 
west. Temperatures today have been unseasonably warm under broad 
southwesterly flow, with highs this afternoon pushing into the upper 
50s to lower 60s. Tonight, expect an area of surface low pressure to 
develop over the Central Plains and quickly move northeast into the 
Great Lakes region by Tuesday morning as a shortwave trough pushes 
across the Upper MS Valley. The attendant cold front will approach 
from the northwest early Tuesday morning, and then exit off to the 
southeast Tuesday afternoon. With hi-res model guidance trending 
towards a slower onset of precipitation, current thinking is that 
PoPs will begin to increase after sunset over southern IN, and 
gradually spread eastward across the area by midnight EST. The best 
chances of rainfall will be overnight, and then expect rain to taper 
off from northwest to southeast Tuesday afternoon as the cold front 
moves through the area. Overall, expect rainfall amounts will 
generally be under a half inch. 

Lows tonight will remain in the upper 40s to lower 50s as warm, 
moist southerly flow under a blanket of clouds will prevent 
temperatures from falling too much. Expect winds to remain out of 
the south/southwest overnight before beginning to veer to the 
northwest tomorrow morning and afternoon as the cold front moves 
through. Sustained speeds of 10-15 mph are likely this evening and 
again tomorrow afternoon under a tightening pressure gradient.

.Long Term...(Tuesday night through Monday)
Issued at 250 PM EST Mon Feb 17 2020

Tuesday night high pressure will be building into the region from 
the northwest...steadily bringing an end to precip chances across 
our Lake Cumberland region. Cloud cover should linger into the 
afternoon hours Wednesday as we start scouring out the low-level 
moisture with dry air aloft. The center of that high will slow down, 
getting to Iowa Thursday and then across our area Friday night. 
Expect a fairly dry Arctic airmass in place...nice to for once be on 
the other extreme side compared to our very wet pattern of the last 
couple of months. Precipitable waters come down to around a tenth of 
an inch by Friday...according to the 00Z NAEFS. Temperatures should 
go below normal Wednesday likely to Saturday morning.

As we get to the weekend, there has been a fairly consistent signal 
for an upper low to move out of the desert southwest and bring in 
some precip chances starting as early as Sat. night. Model guidance 
has diverged on how the waves of energy track in and then how far 
north a surface low tracks. The GFS brings a surface low into the 
Ohio Valley Monday, whereas the Euro keeps the track more over the 
TN Valley and then eastern KY and the CMC is much more suppressed. 
Cold air in place could make for some rain/snow issues should precip 
make its way this far north for Sunday/Monday...but given model 
spread, it is much too early to too concerned about this system just 
yet.

&&

.Aviation...(06Z TAF Issuance)
Issued at 1238 AM EST Tue Feb 18 2020

Nighttime satellite shows a vast field of MVFR CIGs moving in from 
the west while current LVX radar shows light returns across southern 
Indiana and just upstream of BWG. Regional observations place the 
cold front currently through central MO. As the front pushes 
eastward, CIGs will gradually deteriorate to IFR accompanied by 
light rain and fog. VIS will likely be restricted to MVFR until late 
morning and improve with the passage of the cold front as winds veer 
from SW to NW. All sites should go VFR by Tuesday evening, except 
for LEX where model guidance suggests MVFR CIGs will persist 
overnight.

&&

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

$$

Update...13
Short Term...JML
Long Term...RJS
Aviation...CG