Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 210721
Area Forecast Discussion
National Weather Service Louisville KY
321 AM EDT WED SEP 21 2016
.SHORT TERM (Now through Thursday)...
Issued at 305 AM EDT Wed Sep 21 2016
Early morning observations revealed mostly clear skies across the
region this morning. Temperatures generally ranged from the upper
50s to the lower to middle 60s...while the urban hotspots remained
in the upper 60s. No significant weather is expected through
sunrise and temperatures will likely fall a few more degrees before
High pressure at the surface and aloft will continue to strongly
influence our weather in the near term. In terms of sensible
weather, dry and warm conditions are expected to continue. Highs
this afternoon will warm into the 85-90 degree range. Lows tonight
will drop back into the lower-middle 60s. Highs on Thursday will
likely top out in the upper 80s to the lower 90s.
.LONG TERM (Thursday night through Tuesday)...
Issued at 320 AM EDT Wed Sep 21 2016
Wednesday Night through Friday Night...
Strong mid-level ridge axis will remain firmly entrenched across our
region with the belt of westerlies remaining well to our north. So
a continued dry and warm weather pattern will continue through this
time period. Daytime highs will warm into the upper 80s to the
lower 90s with overnight lows the middle to upper 60s.
Saturday through Tuesday...
As we move into the mid to late range periods, we`ll see some
changes in the overall weather pattern. As Saturday unfolds, we`re
likely to see a very large upper trough move from the inter-
mountain west into the Plains. This will strengthen the downstream
ridge over us, so the warm and dry weather will continue into
Saturday with highs in the upper 80s to the lower 90s. The models
had been advertising a bit of a back door cold front pushing in from
the NE which could bring down temperatures a little bit. The GFS
and Euro are a bit different in their solutions with this. In
general, both models have backed off slightly on the cooler weather,
but it does look like our NE sections may get a short reprieve of
the heat on Sunday. Highs Sunday will range from the lower-mid 80s
in the NE to the upper 80s across the SW. Lows Sunday night will
likely exhibit a gradient with upper 50s to around 60 in the NE with
lower-mid 60s in the SW sections.
By Monday, it appears that we`ll see an extremely amplified upper
air pattern setting up with a deep/full latitude trough axis over
the central US with a downstream ridge over the east. The ridge
axis will remain over us on Monday keeping us dry and warm. However,
the upper trough will likely close off and slowly move eastward
toward the Ohio Valley by Tuesday. Given the upper level
configuration, we`ll see a deep moisture plume extending from the
Gulf into the Midwest. We could our first real chances of rainfall
by Tuesday with some isolated storms possible in the afternoon/eve.
However, our best chances for rainfall look to be around Wednesday
as the moisture plume slowly moves eastward. In addition to the
rainfall, a much cooler airmass looks to invade the region by
Wed/Thu likely pushing temps down some 15-20 degrees from what we`ve
seen of late.
.AVIATION (06Z TAF Update)...
Issued at 1230 AM EDT Wed Sep 21 2016
Deep ridging will keep a mainly dry column in place, so expect
prevailing VFR conditions with mainly clear skies and light E/NE
winds. Only exception is BWG, where there was enough dewpoint
recovery at sunset to raise some concerns about a repeat of Tue
morning IFR visibilities. However, winds are up to 15 kt just 1000
feet off the deck, and should keep the boundary layer mixy enough to
lift the shallow moisture into a scattered stratus deck, so will
only carry a couple hrs of MVFR vis around daybreak.