Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 291043

Area Forecast Discussion
National Weather Service Louisville KY
643 AM EDT Mon May 29 2017

...Updated Aviation Discussion...

.Short Term (Now through Tuesday)...
Issued at 315 AM EDT Mon May 29 2017

Deep and occluded low over Lake Superior will slowly meander into
eastern Ontario through the period. A mid level dry slot wrapping
into the system will stay settled over the Ohio River Valley today,
giving us a nice Memorial Day from a sensible weather standpoint.
Under mostly sunny skies and as steady SW wind, look for highs to
reach the 79-84 degree mark.

As we move toward the late evening and overnight, a shortwave will
rotate through the parent trough, along with a weakly defined
surface boundary. Models hint at just enough convergence along this
feature to warrant isolated to widely scattered shower chances
across southern IN. Can`t rule out a rumble of thunder across our
norther tier or two of counties around sunset, but think mainly
shower chances as thermal profiles would support meager instability.

Look for lows in the upper 50s and low 60s with some sprinkles
possibly sinking south of the Ohio River into Tuesday morning. Will
have to watch for redevelopment ahead of surface boundary in our
eastern CWA again Tuesday afternoon across our far E/SE, but overall
coverage would be very low so will mention mostly dry. Highs Tuesday
should again be in the upper 70s and low 80s.

.Long Term (Tuesday Night through Sunday)...
Issued at 315 AM EDT Mon May 29 2017

Tuesday Night - Wednesday...

We`ll be under the influence of an upper trough through midweek,
with a surface cold front slowly passing through the region.
Isolated to scattered showers and storms are possible ahead of this
feature. Best chances will be mainly over southern Indiana and north
central Kentucky before dawn, and over Kentucky as we move through
the daylight hours. After lows in the 55 to 60 degree range,
Wednesday highs will be roughly 75-80.

Wednesday Night - Thursday Night...

Post-frontal surface high pressure and dry NW flow aloft will hold
during this time, keeping us mostly dry. Other than a possible
isolated shower or storm on Thursday afternoon, we`ll see mostly
clear/sunny skies with highs in the upper 70s to low 80s. Thursday
night lows will jump almost a full 10 degrees from Wednesday night
lows in the mid to upper 50s.

Friday - Sunday...

An unsettled weekend could unfold once again as several moisture
rich disturbances travel along a baroclinic zone set up W-E beneath
the zonal flow aloft. It`s early, but it appears that we would
become moderately unstable in a weak-marginally sheared environment,
all in the presence of PWATs in the 1.75-2" range. These factors
combined with a nearly stationary W-E boundary bring concern that we
could run into a heavy rain scenario as precip efficient
thunderstorms train across the region. We`ve got a long way to go,
but will be worth watching as we progress through the new work week.

Temps through the weekend should range in the upper 70s and low 80s
with lows in the mid to upper 60s.


.Aviation...(12Z TAF Issuance)
Issued at 640 AM EDT Mon May 29 2017

Have some lower cigs around LEX this morning, but so far not at the
other sites. Cirrus shield not helping identify boundaries of these
clouds, but surface stations showing lower cigs around BWG as well,
so have an hour early on in this forecast with low-end MVFR
possible. Conditions should improve quickly after sunrise, with a
steady southwest wind through the day. Showers will move just north
of SDF this evening, but think chances are low enough to keep out of
this forecast package.




Short Term........BJS
Long Term.........BJS
Aviation...RJS is the U.S. government's official web portal to all federal, state and local government web resources and services.