Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 152335
Area Forecast Discussion
National Weather Service Louisville KY
635 PM EST Sun Jan 15 2017
...Updated Forecast and Aviation Discussions...
Issued at 635 PM EST Sun Jan 15 2017
Model time-height sections indicate some mid-level dry air working
into the region this hour, and this area is forecast to stick around
through daybreak Monday. That should mean a gradual decline in the
current drizzle but a return to some patches of dense fog, as either
current low-cloud decks may be able to build down through the night
or breaks in the cloud cover allow ground fog to form. Either way we
will have to watch for fog formation through the night and will
issue a special weather statement to highlight the threat.
.Short Term (Now through Monday Night)...
Issued at 320 AM EST Sun Jan 15 2017
Numerous light rain showers are sliding along and north of I-64,
with scattered showers across central KY. These will continue to
slide east through the afternoon and evening as a mid level
disturbance moves through the zonal flow aloft. Most spots along and
north of I-64 should expect around a tenth of an inch through
Midnight or so. A large temp gradient exists across the region with
upper 30s north, to near 50 south. These temps should stay pretty
similar through tonight, with lows mirroring our current temps. The
overall stagnant low level flow combined with trapped low level
moisture should continue to result in patchy fog through the
Upper ridge axis slides over our region by Monday, helping to lift
the warm front north of our region. The morning will likely start
off dry, however isentropic lift picks up through the afternoon
ahead of storm system moving out of the eastern Plains. Best chances
by afternoon will be west of I-65. With the warm front lifting
north, expect mid 60s south, with upper 50s to around 60 north for
Deeper moisture and better forcing arrive Monday night as the
shortwave trough and associated surface low move across the lower
Great Lakes. Some elevated instability will accompany the deep
moisture plume so will include a slight chance of thunder to go along
with widespread rain chances. Temps won`t drop off much on Monday
night ahead of the approaching cold front. Look for mid to upper 50s
.Long Term (Tuesday through Sunday)...
Issued at 320 PM EST Sun Jan 15 2017
Tuesday through Wednesday Morning...
Widespread showers, and a few thunderstorms push east through the
region ahead of a cold front on Tuesday. Highs should range in the
low to mid 60s. Most spots should pick up between a half and three
quarters of an inch of rain by the time precipitation winds down
early Tuesday evening.
Can`t completely go with a dry forecast Tuesday night into Wednesday
morning as a secondary shortwave trough axis looks to swing through.
That being said, these periods should be mostly dry with best
chances for an isolated shower across our far south or eastern CWA.
Lows Tuesday night should drop into the upper 30s and low 40s in
Wednesday Afternoon - Thursday...
This is expected to be a mainly dry stretch of weather as amplified
upper ridging develops over us in response to upstream overall
troughing. Afternoon highs on Wednesday will be cooler than previous
days, but still well above normal in the 50 to 55 degree range.
After Wednesday night lows in the upper 30s and low 40s, highs
Thursday jump to the 55 to 60 degree range. Will bring in low
chances for rain later Thursday if fast solution offered by 12z
ECMWF/GFS Ensemble mean pans out. More on this storm system below...
Thursday Night - Sunday...
Models diverge Thursday night through the weekend as a complex upper
pattern takes hold. At this point, there looks to be a decent signal
for widespread rainfall sometime in the later Thursday through later
Friday time frame as a moisture rich system ejects out of the Rio
Grande and south Plains. After a potentially dry stretch later Friday
night into Saturday, another round of rainfall could occur Saturday
night into Sunday.
Overall, this should be a continued mild stretch with highs in the
upper 50s and low 60s. Lows should mostly be in the upper 40s.
.Aviation...(00Z TAF Issuance)
Updated at 625 PM EST Sun Jan 15 2017
Persistent poor flying conditions expected to continue into Monday,
when a warm front finally will lift far enough north to allow some
warmer air to mix the lower ceilings northward. Seeing better
conditions at LEX this hour, but all surrounding sites as well as
model data indicate this should be short-lived. A cold front will
approach the region Monday night, which will bring a return to
better rain chances and perhaps thunder at KSDF late in its period.