Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 082007
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
307 PM EST Sat Mar 8 2014
.SHORT TERM (Now through Sunday Night)...
Issued at 250 PM EST Sat Mar 8 2014
The synoptic pattern this afternoon features a broad ridge over the
western CONUS, with a downstream trough over the central CONUS.
This trough axis will swing through the region tonight into Sunday
morning, with the flow going more northwesterly on Sunday in its
Clouds will be on the increase this evening as a surface cold front
approaches the region. As of 2:30 PM EST, this front stretched from
south-central IN southwest into southern IL and far southeastern
MO. Just behind this boundary, some light shower activity has
broken out ahead of the upper-level trough axis swinging through the
central CONUS. The latest guidance continues to back off of
precipitation chances tonight, showing a very dry mid-level airmass
winning out. Latest AMDAR soundings show this dry airmass well.
Given the drier trend, have continued to adjust pops downward, now
in the 20-30% range. Think the best coverage of showers will be
across southern IN and northern KY this evening, before the shower
activity really tapers of as it drops southeast into central and
southern KY. Anything that falls will be quite light in nature.
Cooler air will work in behind the surface cold front on Sunday.
However, full March sunshine will help to warm things into the low
and mid 50s, right around normal for this time of year.
On Sunday night, skies will continue to remain generally clear.
However, the surface pressure gradient will tighten a bit as an area
of low pressure passes through the northern Great Lakes. With
southwesterly winds slowly increasing through the night, will go on
the higher end of guidance for lows, which puts them in the mid and
.LONG TERM (Monday through Saturday)...
Issued at 305 PM EST Sat Mar 8 2014
A warm, sunny start is in store for the first portion of the work
week. We`ll be in zonal flow Mon and the first part of Tues in
between weather systems. In low levels, a warm SW wind will warm
temps well into the 60s with some locations reaching 70 Tues
Precipitation in the form of rain still looks likely Tues
Night/Wed. A southern stream upper low and a potent northern stream
trough look to phase just east of our area Wed. As these waves come
together, a low pressure will develop over the southern Plains and
move east through the Ohio Valley Wed. Although timing of this
system and its phase are still in question, the best window for
precip still looks to be Tues Night/Wed. If some of the slower more
amplified models verify, we could see light precip linger into Wed
night. Overall this system looks like mostly rain, but a light mix
may be possible over southern Indiana/northern Kentucky on the very
tail end of the precip Wed night. This light brief mix at the end
of this system doesn`t look to cause negative impacts at this time.
Temps Wed/Thurs will cool off into the 40s for highs and upper 20s
to lower 30s for lows.
The cooler temps will be short lived with slight ridging and more
zonal flow returning to the Midwest by Fri. Another upper level
wave looks possible for next weekend, but models vary greatly on the
upper level pattern by next weekend. Will include a 20-30% chance
of rain on Sat/Sat night at this time but that could change. Temps
Fri/Sat/Sun should moderate into the 50s for highs with 30s for lows.
.AVIATION (18Z TAF Update)...
Updated at 1212 PM EST Sat Mar 8 2014
High clouds continue to stream by early this afternoon in advance of
a cold front. The cold front currently stretches from central IN
southwest into southern IL and southeast MO. Behind this front,
some light precipitation has persisted across portions of southern
MO. There remains some uncertainty as to how much precipitation
will make it into the terminals this evening into tonight, as the
current area is rapidly weakening as it encounters a drier airmass
over the Ohio Valley. Overall, guidance has trended drier, thus
will continue with only VCSH wording at KSDF and KLEX.
Precipitation looks less likely to impact KBWG, thus will keep all
precip mention out at this time. Behind the front, ceilings will
drop to MVFR thresholds for a time overnight, before quickly
returning to VFR by Sunday morning.
Winds will be out of the southwest at 8-12 knots today, before
switching to NNW around 6-10 knots tonight as the front pushes
through. Winds will go light and variable by Sunday morning as high
pressure builds into the region.