950 
FXUS63 KLMK 102350
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
650 PM EST Fri Jan 10 2020

...Updated Aviation Discussion...

.Short Term...(This evening through Saturday)
Issued at 330 PM EST Fri Jan 10 2020 

Tonight, a cold front oriented from Chicago southwest to northern 
Texas is being pushed east by an upper trough. Ahead of the front, a 
low level jet is carrying lots of Gulf moisture north at 50+ knots. 
Precipitable water values climb to near 1.4" in the Ohio Valley. All 
this warm air will keep temperatures from falling, and the moisture 
will fuel rain showers ahead of the front. 

Tomorrow, as the upper trough slowly moves northeast pushing the 
cold front east, rain continues. Temperatures will continue to warm 
to near 70 for many in southern Indiana and into the low 70s for 
those in central Kentucky as strong surface flow continues from the 
south. Precipitable water will get a bump to near 1.8". The warm 
cloud layer will stay near 10,000 feet. These are all conditions for 
effecient rainfall. The surface to 850mb shear could be over 60 
knots. That is a lot of low level wind energy. It wouldn't take much 
to get a quick spin up, but luckily instability is very low, near 
250 J/kg. This will help to limit the tornado risk. Wind will be the 
main threat with gusts near 45 mph likely with strong winds being so 
close to the surface.

The soil is already soaked. With heavy rainfall expected, a flash 
flood watch has been issued for tomorrow at 6z until 0z Sunday. 

A wind advisory is in effect from 8z tomorrow until 5z on Sunday due 
to the wind threat.

.Long Term...(Saturday night through Friday)
Issued at 245 PM EST Fri Jan 10 2020

Lingering precip should exit the area late Sat evening, giving way 
to Pacific high pressure. Given that air mass and a fairly zonal 
flow aloft, we'll see dry and mild weather Sunday and Monday. 

Southerly low/mid-level return flow increases beginning Monday 
night, so precip chances will increase from south to north as moist 
air overruns the old front that will still be hung up over the Deep 
South. Best chances for rain will be late Mon night and Tue morning, 
with enough elevated instability for embedded thunder across south-
central Kentucky. Precip chances will continue into Wednesday as yet 
another northern stream wave is able to tap into this moisture feed. 
QPF has been bumped up a bit for this time period, but confidence is 
low given limited run-to-run consistency. 

Now looks like this system will push through by Wednesday night, 
opening the door for cold and dry high pressure Thursday. This 
represents a substantial colder shift from the ongoing pattern, but 
temps will continue to run near or slightly above mid-January 
normals. Precip chances will return Friday ahead of the next system, 
which will already be taking shape over the southern Plains.

&&

.Aviation...(00Z TAF Issuance)
Issued at 650 PM EST Fri Jan 10 2020

Light to moderate showers will continue to ride over the TAF sites 
on deep SW flow overnight, along with steady to gusty S winds of 10 
to 20 mph, gusting up around 25 mph at times. Expect to stay mostly 
VFR for ceilings, although a few of the brief stronger showers could 
reduce vis into MVFR. HNB will have the best shot at some MVFR 
ceilings overnight.

Winds increase in magnitude in the pre-dawn hours with more shower 
activity likely to occur. Most gusts are expected to be in the 30 to 
40 mph during this time. After daybreak, a line of stronger showers 
and storms is expected to move through although timing is still 
fairly low confidence. Included 6 hour prob30 windows for the sites 
for best timing, where vis could easily go IFR in heavy 
showers/storms and SSW winds could gust above 40 mph at times. MVFR 
ceilings are also likely at times. One other hazard to note will be 
a continued low level wind shear threat given the strong low level 
jet just off the surface through this TAF cycle.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...Flash Flood Watch from 1 AM EST /midnight CST/ Saturday through 
     Saturday evening for INZ076>079-083-084-089.

     Wind Advisory from 3 AM EST /2 AM CST/ Saturday to midnight EST 
     /11 PM CST/ Saturday night for INZ076>079-083-084-089>092.

KY...Flash Flood Watch from midnight CST tonight through Saturday 
     afternoon for KYZ023.

     Wind Advisory from 3 AM EST /2 AM CST/ Saturday to midnight EST 
     /11 PM CST/ Saturday night for KYZ023>043-045>049-053>057-
     061>067-070>078-081-082.

&&

$$

Short Term...KDW
Long Term...RAS
Aviation...BJS