Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 020440
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1240 AM EDT Thu Oct 2 2014
...Updated Aviation Discussion...
.SHORT TERM (Now through Thursday Night)...
Issued at 255 PM EDT Wed Oct 1 2014
Streak of consecutive dry days at Louisville likely will end at
either 20 or 21 days. Ridging in place over the area today will
shift into the Appalachians Thursday, as an upper trough and
attendant cold front push into the Midwest. Have continued to back
off on pops during the day Thursday, with only slight chances west
of the I-65 corridor. Model soundings indicate a mid-level
inversion, which should be enough to limit development.
Winds will pick up from the south by late afternoon Thursday, as the
pressure gradient tightens over the region. Timing for the best
chance for rain is a little slower, with the best chances looking to
come after midnight Thursday night. Latest high-res WRF runs all
show a decaying line of storms moving into the region from the west.
With plenty of moisture over the region, high rain chances still
look good, but have backed off on the thunder chances. Any threat
for severe weather will depend on how strong the line is to the west
and how quickly it moves eastward. Current thinking is the storms
will be through here late enough not to have a severe threat.
.LONG TERM (Friday through Wednesday)...
Issued at 315 PM EDT Wed Oct 1 2014
The axis of a sharp potent 500mb trough will move across Missouri
Friday afternoon in the wake of surface cyclone that is forecast to
rapidly deepen as it moves north across Michigan earlier in the day.
This trough will eventually morph into a longwave trough north of
the Great Lakes that will usher in an extended period of cooler
temperatures that should last through the middle of next week.
Scattered to numerous showers, with a chance of thunderstorms, will
continue or develop by Friday morning within a moist airmass ahead
of a strongly forced surface trough. Widespread showers should bring
widespread beneficial rainfall averaging a half inch or more
areawide. A north south orientated cold front will move east of
Interstate 65 mid-day Friday. The NAM especially does develop some
surface-based instability across our eastern counties and eastern
Kentucky during the afternoon. This may lead to the development of
one or more lines of low topped thunderstorms by mid-afternoon near
the Interstate 75 corridor.
Much colder and drier air will pour into the region late Friday in
the wake of the cold front. Blustery northwest winds of 10 to 20 mph
will develop late Friday and again Saturday afternoon. Partly cloudy
skies will develop Friday night. Temperatures will fall rapidly into
the 40s by early Saturday and will likely stay in the upper 50s
Saturday, especially across our northern counties where some
afternoon strato-cu may develop.
High pressure will settle over Arkansas Sunday, switching our winds
briefly around to the southwest. Expect a decent warmup Sunday, with
highs rebounding around 10 degrees above those of Saturday. A second
reinforcing shortwave will rotate around the by now established
longwave trough north of the Great Lakes on Monday. This feature
will stay relatively moisture starved, but may bring some showers
late Monday through Tuesday. Temperatures Monday and Tuesday will
steady out at about what should be considered close to normal for
early October, with highs near 70 and lows in the 50s.
.AVIATION (06Z TAF Update)...
Issued at 1240 AM EDT Thu Oct 2 2014
One more quiet TAF period as we sit between high pressure along the
east coast and a storm system approaching from the west.
Not as much fog or low cloud is expected this morning. LEX stands
the best chance of anything sub-VFR around dawn.
Winds will become southerly during the daylight hours today and
continue into tonight, around speeds of 8 to 10 knots. Could see a
few gusts into the teens this afternoon.
Prevailing showers with the nearing cold front will hold off until
after midnight tonight.