Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 252007
Area Forecast Discussion
National Weather Service Louisville KY
307 PM EST Sat Feb 25 2017
.Short Term...(This evening through Sunday night)
Issued at 240 PM EST Sat Feb 25 2017
The upper level trough has shifted to the east of the region this
afternoon and flow aloft has become more zonal. This zonal flow
aloft will continue until tomorrow night when it becomes more
southwesterly and a shortwave approaches. At the surface, high
pressure will build across the area overnight. It will shift
eastward through the day tomorrow with return southerly flow setting
The flurries and light snow showers from this morning have mostly
ended with just a few returns showing up in southern IN. These
should end over the next hour or two. Thereafter, we will see
clearing skies tonight as the high pressure builds in. Sunday will
will start out clear and dry, but clouds will be on the increase in
the afternoon as the shortwave approaches. This wave will bring
scattered light showers tomorrow night. A bit of snow could mix in
towards dawn on Monday across the Bluegrass region, but this should
have no impact or accumulations.
Temperatures tonight will be cold, dipping into the lower to mid
20s. We will see a warm up tomorrow (compared to today at least)
with highs topping out in the mid 40s to around 50. Lows tomorrow
night look to dip into the mid to upper 30s.
.Long Term...(Monday through Saturday)
Issued at 304 PM EST Sat Feb 25 2017
Monday - Tuesday...
The first half of the long term period will be rather active as
multiple waves move through the upper level flow aloft. The first
will be with the ongoing showers Monday morning. These showers look
to diminish in coverage by Monday afternoon as the wave pushes east.
However, another one will slide through Monday night into Tuesday.
These look to start out as just showers, but soundings do show
instability developing during the day on Tuesday as temperatures
warm into the upper 60s to lower 70s. Therefore, will continue to
mention thunderstorms on Tuesday.
Tuesday Night - Wednesday Night...
A stronger trough will develop to the west and work its way east
into the lower Ohio Valley through this time frame. Its associated
surface low will track from the Plains Tuesday into the Great Lakes
region Wednesday and off to the northeast by Thursday morning.
We could have couple of rounds of showers and storms associated with
this system, first on Tuesday night and then again on Wednesday as
the front actually moves through. Once again we are looking at some
decent wind profiles and surface based CAPE values of at least 500-
1000 J/kg developing Wednesday. Right now this system looks somewhat
complicated given the potential for a couple of rounds of storms.
CIPS analogs Hazard Guidance does show the potential for severe
weather with this system. Additionally, SPC does have a portion of
our region in the Day 5 outlook. It therefore bears watching over
the coming days.
Thursday - Saturday...
A few snow flurries may mix in behind Wednesday`s system, but most
of the precip should move out before it does. Another wave looks to
pass through the upper level flow Thursday night and should mainly
bring some light snow/rain to northern portions of the Bluegrass
region. Otherwise, this time frame should be mainly dry.
Temperatures will be closer to normal Thursday and Friday behind the
cold front, but warm back into the 50s again on Saturday.
.Aviation (18Z TAF Update)...
Issued at 1227 PM EST Sat Feb 25 2017
A deck of stratocu about three thousand feet thick according to
(much appreciated) PIREPs is pivoting across the region beneath an
upper trof. The clouds have managed to drop some flurries but no
more than that is expected this afternoon. As a matter of fact, even
the flurries should cease, though at least sct-bkn clouds will hang
on through much of the daylight hours. Ceilings will be low-end VFR.
Winds will remain gusty from the WNW this afternoon.
Clouds will clear out from west to east this evening as high
pressure advances from the Ozarks to the Tennessee Valley. Winds
will become light and variable.
On Sunday we`ll get into return flow with S-SSW breezes and
increasing high clouds.