455 
FXUS63 KLMK 191127
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
627 AM EST Sun Jan 19 2020

...Updated Aviation Discussion...

.Short Term...(Today and tonight)
Issued at 235 AM EST Sun Jan 19 2020

Fairly quiet morning across the region, with just some low clouds 
streaming across southern IN/northern KY as time heights show low 
level moisture continuing to linger through this morning. A surface 
low is currently centered over southern Ontario and will continue to 
push off to the east today as high pressure begins to slowly glide 
southeastward through the Northern Plains and build in across the 
central CONUS.  

The main concern during the short term period will be the cold 
temperatures. As strong CAA continues to bring in arctic air from 
the northwest, temperatures this morning will tumble into the low 
teens across southern IN and into the mid 20s in southern KY. These 
colder temps combined with the breezy winds will result in wind 
chill values this morning near zero in southern IN and into the low 
teens in southern KY. Despite partly to mostly sunny skies today, 
temperatures will struggle to reach above freezing this afternoon, 
with wind chills likely remaining below 20 degrees throughout the 
day. Low temperatures Sunday night into Monday morning will be in 
the mid teens, with wind chills in the single digits to low teens.

.Long Term...(Monday through Saturday)
Issued at 217 AM EST Sun Jan 19 2020

Monday through Thursday:

Though a compact upper vort max will pass over the region Monday 
night, a large dome of Canadian surface high pressure will keep us 
dry as it progresses from the Plains on Monday to the Ohio Valley 
Tuesday and to the mid-Atlantic Thursday. The source region of the 
high was in northern Canada and the frigid air mass will be sliding 
over deep snow cover across the upper Midwest and northern Plains 
before it gets here, so we can expect chilly temperatures when it 
arrives. Maximum temperatures Monday and Tuesday will mostly be in 
the 30s with bus stop temperatures Tuesday morning in the teens. 
Fortunately winds will be very light.

Thursday night through Saturday:

An upper low will progress from the central Plains to the Great 
Lakes. The details at the surface haven't quite been ironed out yet, 
but the general idea is for rain to be in the forecast from late 
Thursday night into Saturday as return flow behind the 
aforementioned high interacts with the incoming trough. Precipitable 
water values will not be particularly high, peaking around an inch 
on Friday, and instability will be very weak, so just light rainfall 
amounts are expected. GEFS plumes and the operational ECMWF suggest 
some light snow could come in on the back side of the system 
Saturday, but right now forecast temperatures are just a bit too 
warm for much in the way of snow.

Speaking of snow, no measurable snow has fallen so far in January at 
Louisville, Lexington, and Bowling Green. The last time the entire 
month of January went without measurable snow (a trace or less) at 
Louisville was in 1993...Lexington 1989...and Bowling Green 2008.

&&

.Aviation...(12Z TAF Issuance)
Issued at 620 AM EST Sun Jan 19 2020

Low clouds continue to move across southern IN and north-central KY, 
bringing intermittent periods of MVFR cigs to HNB/SDF/LEX. 
Throughout the morning, these low clouds are expected to begin 
scattering out from west to east, with VFR conditions likely at all 
TAF sites by this afternoon. Sustained wind speeds continue to hold 
at 10-15 kts out of the WNW across much of the area, with gusts of 
up to 20-25 kts. Winds are expected to gradually diminish towards
sunset.

&&

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

$$

Short Term...JML
Long Term...13
Aviation...JML