Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 202005

Area Forecast Discussion
National Weather Service Louisville KY
305 PM EST Sat Jan 20 2018

.Short Term...(This evening through Sunday night)
Issued at 306 PM EST Sat Jan 20 2018

Now - Tonight...

Deeper moisture is pooling into the area as W to E low level jetting
slowly backs to a more SW component. As this occurs, drizzle and/or
light rain showers will be possible mainly across southern IN and
north central KY later this evening. Temps in the upper 40s and low
50s likely won`t go real far tonight as the steady S wind combines
with the increased cloud cover. Only have lows dropping off into the
low and mid 40s, with continued scattered rain showers mainly across
the northern half of the CWA. Will also mention some foggy/misty
visibility restrictions mainly up over southern IN tonight.

Sunday - Sunday Night...

Strong shortwave trough ejects out of the SW CONUS into the central
US during this time. The warm sector will become more established
over the area with highs well into the 50s, and mild Sunday night
lows in the mid to upper 40s. Isentropic lift will continue to help
some small light rain chances across the northern CWA. As we move
toward dawn on Monday, the core of a 50+ knot LLJ begins to slide in
from the west where precipitation chances will quickly go up to


.Long Term...(Monday through Saturday)
Issued at 306 PM EST Sat Jan 20 2018

Monday - Tuesday...

A potent upper trough will rotate from the central Plains up through
the Great Lakes, with the associated surface low following the same
path. We`ll be in the warm sector for much of the day Monday,
allowing for one more day of mild temps. Highs should be in the
upper 50s to right around 60. Widespread rain is expected to move
from W to E across the area through the day as deep moisture pools
ahead of the trough in conjunction with good forcing from a dynamic
system. Overall, the system stays pretty progressive, and most
places should expect around a quarter to as much as a half an inch
of rainfall.

A very pronounced dry slot will then slide over the area from W to E
later Monday afternoon through Monday evening, which will likely
shut off precipitation, but also help to introduce gustier cold
advection winds behind the front. At this point, expect gusts
somewhere in the 25 to 35 mph range.

Temps fall off behind the front Monday night, back into the mid and
upper 30s for lows and we look to stay mostly dry as we remain in
the dry slot. Drizzle or a few light sprinkles could begin to work
into our northern counties later Monday night into Tuesday as
trapped low level moisture begins to spill back in from the north.
It`s possible it could get just cold enough for a few snowflakes,
but not really worth mentioning right now. Otherwise, Tuesday is
mostly dry and cooler with highs topping out around 40.

Tuesday Night - Saturday...

Dry NW flow aloft and surface high pressure dominate through mid
week, before progressive upper ridging slides over the area Friday
and Friday night. This will be a dry stretch with steadily warming
temperatures. Highs Wednesday in the low to mid 40s will give way to
highs in the low to mid 50s by Friday. Lows in the mid 20s Tuesday
and Wednesday nights will give way to low 30s Thursday night and the
low 40s Friday night.

By Saturday, a highly amplified upper pattern allows for influx of
deep Gulf moisture ahead of the next trough. Precipitation chances
will begin to enter our western CWA with the associated isentropic
lift. Saturday should also be mild ahead of the approaching cold


.Aviation...(18Z TAF Issuance)
Issued at 1222 PM EST Sat Jan 20 2018

Low level moisture will continue to flow northward ahead of low
pressure crossing Kansas. This moisture is manifesting itself in a
broad swath of MVFR ceilings that will spread throughout central
Kentucky and southern Indiana this afternoon, continuing through
Sunday. Confidence in exact base heights is low, but in general it
seems that airports deeper in the warm sector, LEX and BWG, stand
the best shot at spending some time above fuel alternate, while
chances of 2k`+ ceilings are lower at SDF and HNB.

Winds between the Kansas low and high pressure off the Carolina
coast will consistently come in from the south through tonight and
tomorrow, at speeds near 10kt.




Short Term...BJS
Long Term...BJS
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