Area Forecast Discussion

FXUS63 KLMK 180829
Area Forecast Discussion
National Weather Service Louisville KY
329 AM EST Mon Dec 18 2017
.Short Term...(Today through Tuesday)
Issued at 245 AM EST Mon Dec 18 2017
Low clouds, light fog and patchy drizzle will continue this morning 
as low level moisture remains trapped in the boundary layer in a 
light zonal flow across the Ohio Valley.  Expect fog to dissipate 
later this morning with sfc visibilities improving but low clouds 
and patchy drizzle look to stay put through late afternoon or 
evening.  Given the cloudy, drizzly conditions, highs this afternoon 
will likely be limited to the upper 40s/lower 50s.  
Expect dry conditions for tonight with perhaps some breaks in the 
clouds.  Low temperatures will range through the lower 40s.
For Tuesday, a southern stream low pressure system will approach the 
area bringing in light rain to southern KY later in the day. A 
strong southerly flow will allow temps to warm into the mid to upper 
50s Tue afternoon.
.Long Term...(Tuesday night through Sunday)
Issued at 320 PM EST Mon Dec 18 2017
Tuesday Night - Thursday...
A low pressure system moving through the TN valley will bring light 
rain to portions of central and southern KY Tues night through Wed. 
Rainfall amounts will range from a few hundreths over central KY up 
to three quarters of an inch near the KY/TN border.  It will be a 
cold rain with temps in the 40s to around 50 Tue night into Wed. 
Outside of the rain, temps look to dip into the mid 30s Tue night in 
S. Indiana.
Expect a dry period Wed night-Thursday.  After a cold night Wed 
night in the upper 20s/lower 30s, temps will rebound in earnest in a 
strong southerly flow for Thur.  Highs on Thu should range through 
the 50s and approach 60 in some locations. 
Friday - Saturday...
A strong cold front is expected to push through the region for the 
end of the week bringing widespread rain and perhaps a rumble of 
thunder.  Long range models have timing issues with the 0Z GFS being 
on the faster side and the 0Z ECMWF on the slower side.  A blend of 
the models yields the best precipitation chances late in the day 
Friday through Fri night.  At this time, the majority of this 
precipitation looks to be plain rain.  Rainfall totals for Fri-Sat 
of 1-1.5 inches are possible given unseasonably high precipitable 
water values.
Temps on Fri should be in the 50s to around 60 and then fall back 
into the 40s/lower 50s for Sat.
Sunday - Monday...
There is very low confidence in the forecast for Christmas 
Eve/Christmas Day at this point.  Long range models continue to show 
very drastic solutions and a lot of flip-flopping from run to run. 
There is certainly a decent chance of precipitation some time 
Christmas Eve-Christmas Day.  However, how much and what type are 
very difficult to answer at this point.  With the potential for 
wintry weather during the holiday on the table, it is advised that 
all holiday travelers stay up-to-date of the forecast for Christmas 
.Aviation...(06Z TAF Issuance)
Issued at 1221 AM EST Mon Dec 18 2017
Stratus, low visibilities, and patchy drizzle will be the main theme 
going forward with the forecast. Cigs/vis currently vary from MVFR 
to LIFR across the region, and expect those to continue to 
deteriorate as we move through the early morning hours. We will 
begin to see cigs/vis improve shortly after sunrise, but some 
uncertainty remains as to how much they will improve. Will stick 
with a more pessimistic forecast for now but there are signs we 
could see VFR cigs/vis for KHNB/KSDF/KBWG toward the end of the 
forecast period.
Short Term...AMS
Long Term...AMS