Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 090138
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
838 PM EST Sat Mar 8 2014
Issued at 835 PM EST Sat Mar 8 2014
Forecast remains on track this evening. Mostly cloudy skies were
noted across southern Indiana and central Kentucky. A cold front
was progressing southward through the state. Ahead of this front, a
band of light rain showers was noted...generally along and just
south of the BG and WK Parkways. We expect this precipitation to
continue to work its way eastward this evening while the overall
line continues to sink southward. The front should clear the KY/TN
later tonight with cooler air pushing into the region from the north.
For this update, have dropped precipitation in areas north of the
Ohio River and will continue the chance PoPs across central and
south-central KY into the overnight hours. Clearing will work in
from the north late tonight which will allow temperatures across
southern IN to drop into the upper 20s with lower-middle 30s across
much of central Kentucky.
.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 (00Z TAF Update)...
Updated at 615 PM EST Sat Mar 8 2014
Overcast conditions will persist at the terminals through the first
half of the forecast period. Surface cold front has passed through
KSDF as alluded by the wind shift in the last 20 minutes. Expect
front to pass through KLEX in the next hour or so and then through
KBWG later tonight. Regional radars do show some scattered light
rain showers pushing eastward across the area. Abundant dry air in
the middle levels is allowing most of the precipitation to evaporate
before hitting the ground. Some saturation is occurring to the
west, so still think there is a possibility to see some VCSH at the
KSDF and KLEX this evening. As the night wears on, we expect MVFR
cigs to persist overnight and then start to lift toward sunrise.
Surface winds at KBWG and KLEX will be out of the WSW/SW this
evening and then shift to the northwest. KSDF will see winds
remaining out of the NW through the period.