Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 201845
Area Forecast Discussion
National Weather Service Louisville KY
245 PM EDT Thu Oct 20 2016
.SHORT TERM (Now through Friday Night)...
Issued at 230 PM EDT Thu Oct 20 2016
...Much Cooler Starting Tonight...
Weak surface gradient over the region now, as the frontal boundary
is roughly over the region. That gradient will tighten up quickly
behind the boundary later this afternoon, with temperatures dropping
quickly behind it. Instability aloft may allow for some elevated
showers as the upper trough axis swings through overnight. Still
cannot rule out some lingering light rain showers in our east Friday
morning, but that should taper off in the afternoon. Friday will be
a raw day, especially when compared to our record heat this week.
Winds will gust out of the northwest and temperatures will not rise
too much...likely staying in the 50s for most locations north of the
Friday night, model consensus places the center of the surface high
over eastern AR/western TN with a ridge axis extending north to
northeast. That could mean our normally colder spots in the
northeast could be spared from frost because of a gentle northwest
breeze overnight. Points west of a Louisville to Liberty, KY line
would have a better chance though. For now have gone with lows
in the upper 30s to around 40. Frosty tool gave patchy frost pretty
much areawide based on this temperature forecast.
.LONG TERM (Saturday through Thursday)...
Issued at 240 PM EDT Thu Oct 20 2016
The high will move into the Deep South Saturday and stay there for
the weekend. That pattern will mean a westerly Saturday and then a
southwesterly flow Sunday. After that, a dry reinforcing cool front
will move through on Monday followed by high pressure moving by to
our north Tuesday. The next rain chance will come Wednesday night
and Thursday, as guidance has another front dropping into the
Midwest. Confidence in timing is average for a Day 7 event, given
some spread between models in the handling of this shortwave
Temperatures Saturday will be similar to Friday`s, but with a little
less wind. The rest of the period looks to be closer to normal.
Sunday the southerly component to the wind should warm us up and
then the front Monday will not bring much of a change in airmass.
.AVIATION (18Z TAF Update)...
Issued at 117 PM EDT Thu Oct 20 2016
First batch of convection is currently moving through the I-75
corridor and will continue to move off through the coalfields of
east KY this afternoon. Second batch of showers is lifting through
the Pennyrile region of western KY and will pass through the I-65
corridor in the next several hours and then through the I-75
corridor later this afternoon and evening. Flight conditions will
generally be low end MVFR to high end IFR this afternoon. Ceilings
are expected to be between 600-1500 ft AGL this afternoon and
continue through the overnight hours. Winds will start off out of
the south and shift to the west/northwest this afternoon at KSDF and
KBWG and then at KLEX by early evening. Winds this evening will be
out of the northwest and gusty with sustained speeds of 10-12kt and
gusts up to 20kts at times.
Ceilings overnight look to remain IFR at all the sites. Some light
rain and mist will be possible at all the terminals. Ceilings will
likely start to rise a bit after dawn on Friday...most likely after