286 
FXUS63 KLMK 082323
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
623 PM EST Tue Dec 8 2020

...Updated Aviation Discussion...

.Short Term...(This evening through Wednesday)
Issued at 249 PM EST Tue Dec 8 2020

A thin stratus deck continues to plague the region at this hour, 
although it is showing some recent signs of beginning to waver. Most 
notably, visible satellite imagery shows the western edge steadily 
eroding across the lower Ohio and Wabash River Valleys in response 
to a 925 thermal axis beginning to nudge into the area. If trends 
continue, some gradual clearing could work into our west in the next 
couple of hours, albeit around or just before sunset. As a result, 
temperatures aren't going to really go any farther today and most 
highs will be confined to the mid and upper 30s with a few spots in 
the low 40s.

As we go into the evening and overnight, do expect a gradual 
scattering out of the low clouds as low level warm advection 
continues across the area, however some upper clouds will stream 
over the area associated with a nice upper jet streak. The end result 
will be variable cloudiness. In addition to the clouds, a steady SSW 
wind expected to pick up. These two factors should keep a pretty 
small range between this afternoon's highs and overnight lows. Most 
spots should only drop around 5 to 10 degrees, which will yield 
upper 20s and low 30s for most spots. Did want to mention that fog 
formation should be limited by the steady surface winds and variable 
upper cloudiness, however the fact that we didn't mix the afternoon 
BL at all, and any evening clearing before the better winds arrive 
could briefly yield some patchy valley fog. Something to at least 
monitor.

We'll keep some variable upper clouds around for Wednesday, but 
overall some sunshine should prevail. A big change arrives with 
temps around 15 to 20 degrees warmer thanks to low level thickness 
rises and a steady SW surface wind. Low to mid 50s is a good bet for 
highs over most of our area, but it isn't completely out of the 
question that our far SW could touch 60.

.Long Term...(Wednesday night through Tuesday)
Issued at 234 PM EST Tue Dec 8 2020

Warming trend continues into the long term as an upper level ridge 
approaches and passes through the region on Thursday. High 
temperatures should easily climb into the mid and upper 50s while a 
few urban areas could briefly hit 60. Friday looks to be the warmest 
day of the week as modest southwesterly flow ahead of a cold front 
aids in advecting in warmer temperatures and low to mid level 
moisture. Highs Friday will likely climb into the low 60s for many. 

Rain showers and even a few rumbles of thunder will be possible 
ahead of the front on Saturday. Low level wind profiles will be 
strong, so it could be a bit breezy at the surface ahead of the 
front if we get a break in the rain and some clearing. Instability 
looks very meager to non-existent given low Td's and marginal lapse 
rates, so not anticipating a severe weather threat. 

Long range guidance begins to diverge on post-frontal solutions 
Sunday into early next week. Some solutions suggest high pressure 
building in from the west and resulting in mostly dry/cool 
conditions through early next week. Other solutions suggest a second 
low developing in the Gulf and being drawn northward into the base 
of a large scale trough in the southeastern US. Wrap-around moisture 
associated with that low in this scenario could persist into Monday. 
For now, will go with blended model output and keep PoP chances low 
at the end of the forecast period.

&&

.Aviation...(00Z TAF Issuance)
Issued at 620 PM EST Tue Dec 8 2020

Low stratus deck finally showing signs of giving up as warm air 
pushes in from the west. Expect lower cigs at LEX/HNB to go VFR in 
the next few hours, if not right at 00Z for HNB. Forecast low-level 
moisture profile does show potential for some resurgence by 
daybreak, mainly in the SDF/LEX corridor and only in the morning 
hours. Any brief ceilings will be right near that 2 kft threshold in 
the MVFR range. Skies should clear out the rest of the day. Winds 
will pick up from the southwest and could gust in the 15-20 knot 
range in the late morning to mid afternoon hours.

&&

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

$$

Short Term...BJS
Long Term...DM
Aviation...RJS