Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 260136
Area Forecast Discussion
National Weather Service Louisville KY
936 PM EDT MON JUL 25 2016
Issued at 936 PM EDT Mon Jul 25 2016
The overnight hours should be quiet with just a few showers and
perhaps a rumble or two of thunder. Patchy fog will develop towards
morning, especially in locations that received rainfall earlier.
.SHORT TERM (Now through Thursday)...
Issued at 300 PM EDT Mon Jul 25 2016
Old outflow from overnight convection over Indiana has made it into
the I-64 corridor, and is focusing scattered thunderstorms. Very
moist atmosphere is limiting the SVR potential, but locally heavy
rainfall is shaping up as the main threat.
This convection is actually being handled well by the hi-res models,
which shows storms dissipating after sunset with the loss of
heating. Will carry chance POPs into mid-evening, just long enough
to show up in the first full forecast period before trending down to
slight chance for the rest of the night.
Forecast confidence is limited still, but the main theme through the
short term will be scattered diurnal convection each day. Convective
temps will be reached fairly quickly and it remains a boundary-rich
environment, so it`s difficult to even keep the morning dry. Will
ramp up quickly to high chance, and gradually shift the better rain
chances southward in the afternoon. Main storm threats will be
locally heavy rainfall, and wet microbursts, but organized severe
weather is not expected.
Not expecting a real change in air mass, but convection should turn
over the atmosphere just enough to take the edge off both temps and
dewpoints. However, temps will still run near seasonal normals, and
dewpoints will remain in the lower 70s, only slightly less
oppressive than the mid-70s dewpoints of the last couple days.
.LONG TERM (Thursday night through Tuesday)...
Issued at 206 PM EDT Mon Jul 25 2016
We will spend the long term under upper trofiness between a
weakening ridge over the Intermountain West and a retrograding ridge
over the mid-Atlantic. Several embedded waves will likely move
through the mean trof. Best chance of showers and storms will be
Thursday as the first weak wave swings through the trof and
interacts with the stationary front draped across the area. We will
also have the added benefit of a broad surface trof just to our
northwest during the latter part of the work week, with the trof
passing through southern Indiana and central Kentucky probably on
Saturday. We`ll also be positioned near the entrance region of the
upper jet. As these phenomena interact with the warm, unstable
atmosphere scattered showers and thunderstorms will likely break
out. This also is in line with MOS PoPs which are above CLIMO
through the extended.
Temperatures should be near normal with highs in the 80s and
muggy lows around 70.
.AVIATION (00Z TAF Update)...
Issued at 712 PM EDT Mon Jul 25 2016
Though a few showers will still be possible overnight, especially at
SDF, radar trends and model data suggest that the thunderstorm
activity we`ve been seeing over the past few hours will be largely
diurnal. So, will go ahead with a mostly dry overnight forecast.
With high dew points plus some rainfall, will bring in MVFR vsbys in
BR early Tuesday morning at all sites.
A very weak surface trof just north of the Ohio River this evening
will sag southward across the river tonight and through central
Kentucky Tuesday. As a result, scattered thunderstorm activity can
once again be expected Tuesday.