Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 290503
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
103 AM EDT Sun Mar 29 2015
...Updated Aviation Discussion...
Issued at 931 PM EDT Sat Mar 28 2015
Clear skies and light winds will allow temperatures to fall a good
clip this evening. This will be most prevalent in the Bluegrass
region where temperatures will cool in the upper teens to lower 20s
again. Slightly warmer temps will be found in the west and
southwest where a little southerly flow will keep temperatures up
slightly. Did a quick update to the hourly T/Td grids to bring them
in line with current observations.
.SHORT TERM (Now through Sunday Night)...
Issued at 300 PM EDT Sat Mar 28 2015
An amplified yet progressive pattern at 500mb will feature a sharp
trough that will move towards New England this evening, and a second
trough moving east towards the Dakotas.
For the Lower Ohio Valley, high pressure will slowly move southeast
across eastern Kentucky this evening, before sliding southeast
towards Georgia by Sunday afternoon. One more unseasonably cold
night expected tonight before a `slow` moderating trend in
temperatures begins Sunday. Expect clear skies tonight with light
north winds becoming variable, and then switching to the southeast
towards dawn. With good radiational cooling conditions, low
temperatures will drop sharply this evening, bottoming out shortly
after midnight in the lower to mid 20s. Expect a few teens across
our normally colder Bluegrass locations.
A vigorous surface low will move north of Lake Superior tomorrow,
tightening our pressure gradient across the region. Light south
winds will increase by early to mid afternoon to 10 to 15 mph, with
higher gusts. After a sunny, morning, expect high clouds to dim the
sun by early to mid afternoon. Highs will reach the mid to upper
50s, with some lower 60s possible south of Bowling Green.
A cold front will move southeast of the Ohio River around midnight
or early Monday morning. Despite a lack of moisture, strong forcing
will bring cloudiness Sunday evening through early Monday and a
likelihood of some light rain. Precipitation amounts will stay less
than one tenth of an inch most locations.
.LONG TERM (Monday through Saturday)...
Issued at 256 PM EDT Sat Mar 28 2015
Monday through Monday night will be dry as high pressure moves from
the Ozarks through the Tennessee Valley to the southern
Appalachians. It won`t be a very strong high and will be of Pacific
origin, so temperatures will be right where they should be for the
end of March.
A clipper-type system will roll across the Great Lakes on its way to
the Jersey shore Tuesday through Tuesday night, swinging a cold
front through the LMK CWA. The GFS has trended wetter with this
system, but it`s a recent trend and is at odds with this morning`s
runs of the ECMWF and GEM, so will continue the dry forecast for
Tuesday and Tuesday night. Temperatures should be near or a little
By Wednesday night we`ll be in return flow behind high pressure off
the East Coast and an approaching storm system over the Plains.
Isentropic lift will increase, especially west of I-65 after
midnight, and will coincide with enough moisture to prompt the
possibility of some light rain showers. Low temperatures will be
held up around 50.
Much better chances for showers, along with some thunderstorms, will
come Thursday/Thursday night as that Plains system pushes through,
and then again on Friday/Friday night as a second system crosses the
It`s still a long way off, but Friday afternoon could be interesting
with strong dynamics both aloft and in the lower levels with PWAT
possibly peaking around 1.3 inches and surface dew points 15 degrees
warmer than normal as that second system comes in. There`s still a
lot of model disagreement, though, so at this point it`s just
something to watch.
Daytime temperatures Wednesday through Friday will be in the 60s to
around 70, with morning temperatures Thursday and Friday around 50.
Saturday morning will be cooler behind the Friday system, in the
lower to middle 40s.
.AVIATION (06Z TAF Update)...
Issued at 102 AM EDT Sun Mar 29 2015
Surface high pressure and upper level ridging will keep conditions
mostly clear and VFR through most of this forecast cycle, before
conditions deteriorate this evening and overnight ahead of a cold
Surface high pressure centered over the area now will scoot off to
the east through the day with SE winds gradually veering to SSW and
increasing in magnitude through the day. In fact, expect 10 to 15
mph SSW winds with gusts up around 25 mph at times this afternoon.
Upper clouds will also begin to overspread the area this afternoon,
with bkn VFR ceilings beginning early this evening at SDF/LEX. Rain
showers are then expected between 8 and 10 PM EDT at SDF/LEX and
around Midnight EDT at BWG with some periods in MVFR in vis/cigs
possible. Cold front passes overnight with veering winds to NW and
some lingering stratocu that could flirt with MVFR thresholds.