Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 280159
Area Forecast Discussion
National Weather Service Louisville KY
959 PM EDT WED APR 27 2016
Issued at 958 PM EDT Wed Apr 27 2016
Increasing CIN and loss of instability is keeping line of storms
below severe limits so far. Automated sites, observations and public
reports in the last 1 to 2 hours have indicated gusts in the 30 to
45 mph wind range along with some pea to dime sized hail. In
addition, there has been torrential downpours with some ponding on
Will continue to cancel the SVR watch as the line progresses, and
may be able to cancel the entire thing soon if the line continues to
Issued at 610 PM EDT Wed Apr 27 2016
Convection firing up along a residual east/west boundary across
central Kentucky has been the interest so far this afternoon and
early evening. Environment is characterized by 1000 to 1500 J/kg of
SBCAPE with effective bulk shear of 40 to 50 kts. An area of
enhanced low level helicity exists as well, which is helping to
sustain some of the supercells across west-central KY.
As a result, feel there is a short-lived tornado threat and tornado
watch has been posted for portions of the western areas. And further
back south/west, we`ll have to watch the main line of storms roll
through the area later this evening. Hi-res models have a good
handle on this coming through with the potential for a damaging wind
and hail threat.
.SHORT TERM (Now through Thursday Night)...
Issued at 312 PM EDT Wed Apr 27 2016
As an upper low moves between Omaha and Des Moines tonight and a
speed max rounds its base, scattered showers and storms are expected
to develop INVOF the confluence of the Ohio and Mississippi Rivers
late this afternoon/early this evening. This convection should then
head northeast up the Ohio Valley. Scattered storms will also be
possible over the rest of central Kentucky in the warm and unstable
sector south of a warm front stretched out along Interstate 64.
There has been a lot of rain already today, limiting surface-based
instability along and either side of the warm front. The warm front
is not expected to move much other than perhaps a slight northward
drift. This would bring more unstable air slightly northward despite
earlier rains. In short, it will be an evening of monitoring radar
and satellite trends to see exactly where new convection sets up to
our west/southwest and moves into the area. WBZ heights around 10k
feet support hail as the main threat. If the surface remains
relatively stable the wind threat may be slightly lessened...but
will have to see how the warm front behaves and how much of a break
we can get between afternoon convection overhead and incoming
convection from the west this evening.
There has been torrential rain over a narrow band between
Elizabethtown and Mammoth Cave this afternoon, resulting in some
minor hydro issues in that area. Additional water problems will be
possible this evening under the heaviest rainers, especially in
Tomorrow the upper low will weaken and advance into the Great Lakes.
By afternoon lapse rates and cu rule support sct/bkn cu development.
PWATs look quite low and atmospheric cross-section show very little
available moisture. Can`t rule out pop-up afternoon showers, though,
especially from southern Indiana to the Kentucky Blue Grass.
Thursday night high pressure will nose in from the northwest and
give us a pleasant night with temperatures dropping into the lower
and middle 50s.
.LONG TERM (Friday through Wednesday)...
Issued at 322 PM EDT Wed Apr 27 2016
High pressure to our north will give us a very nice day on Friday
with partly cloudy skies and temperatures peaking in the 70s.
We then enter into what should be a very wet weekend. Low pressure
will lazily move from the Red River Valley Saturday morning to the
mid-Atlantic coast by Sunday evening. The Gulf will be wide open and
models are progging a healthy low level jet bringing moisture
northward. Widespread showers and scattered thunderstorms will be
the result. One to three inches of rain over the course of the
entire weekend isn`t out of the question.
Things should then dry out for the first part of the new work week
before the next system begins to approach by mid-week.
High temperatures throughout the long term will be in the 70s,
although some locations may not make it out of the 60s in southern
Indiana on Saturday.
.AVIATION (00Z TAF Update)...
Updated at 659 PM EDT Wed Apr 27 2016
A line of intense storms will impact BWG by 00z, SDF closer to 01-
02z, and LEX by around 03-04z. SDF stands the greatest chance of
seeing a harder hit with strong to severe winds, frequent
CG lightning and torrential rain for 1 to 2 hours.
In the wake of this complex of storms, expect plenty of low level
moisture and combined with nighttime cooling, there`s a chance of
IFR to low MVFR ceilings developing by 06z or so, holding through
dawn or so. Guidance hits the IFR probabilities the hardest at
For Thursday, some broken MVFR ceilings likely in the morning but
conditions should begin to improve with daytime heating and some
drier air. Some gusty winds will develop in the late morning and
afternoon. Chances for showers/storms are significantly less so will
hold off mentioning anything in the TAF right now.