Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 251910
Area Forecast Discussion
National Weather Service Louisville KY
310 PM EDT MON JUL 25 2016
.SHORT TERM (Now through Sunday)...
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 (Sunday night through Friday)...
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 1230 PM EDT Mon Jul 25 2016
Main near-term concern is convective potential for SDF and LEX this
afternoon. Earlier storms left a weak outflow boundary somewhere
across north central Kentucky, and this boundary is expected to
focus convection early this afternoon. Will be a last-minute call,
but may need to initialize one or both with VCTS and carry it
through sunset. Will keep BWG dry as most of the effective
boundaries are too far north.
Fog potential tonight is limited and depends on getting some rain
this afternoon. Assuming that happens in LEX, will use a TEMPO for
occasional forays into MVFR or borderline IFR visibilities around
daybreak Tue. BWG does not figure to cross over the dewpoint, but
any storms this afternoon/evening could leave a boundary that would
enhance the fog potential. Will carry a few hrs of prevailing MVFR
Light/variable winds will persist well into the daytime hours
Tuesday, but expect VFR conditions with only a few diurnal cu.