Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 192247
Area Forecast Discussion
National Weather Service Louisville KY
647 PM EDT TUE JUL 19 2016
...Updated Aviation Discussion...
.SHORT TERM (Now through Wednesday Night)...
Issued at 305 PM EDT Tue Jul 19 2016
In the near term, mostly sunny skies are expected to continue across
the region. A few isolated showers and thunderstorms may affect the
KY/TN border counties over the next hour before pushing southward
into middle Tennessee. Temperatures across the region were in the
mid to upper 80s east of I-65 with upper 80s and lower 90s west of
the interstate. We expect maximum temps to occur in the next hour
or two with readings remaining in the 80s during the evening hours.
For the overnight period, we expect a mainly dry period of weather.
Some of the CAMs runs do show convection to our northwest moving
toward the region overnight. However, all the models show this
activity weakening rather quickly and not making it into our region.
So we plan on keeping the dry forecast intact. Overnight lows will
be rather warm with readings in the mid 70s.
On Wednesday, the upper level ridge will begin to build in. However,
tail end of a a mid-level perturbation moving north of the region may
result in some isolated convection across southern IL/IL during the
afternoon. For now, have kept an isolated PoP chance in the
forecast. We`ll see slightly warmer readings on Wednesday with
highs in the 89-94 range. Heat indices will likely be in the 95 to
100 range in the afternoon. Lows Wednesday night should cool back
into the lower 70s...though some of the urban areas may only drop
into the upper 70s.
.LONG TERM (Thursday through Tuesday)...
Issued at 323 PM EDT Tue Jul 19 2016
The multi-model consensus continues to show a strong mid-level ridge
across the central US expanding slightly as we head through the
later half of the week and into the weekend. The overall storm
track will remain just north of the region which may end up keeping
the area slightly drier for the later half of the work week.
Temperatures will likely moderate slightly through the early part
of the period. However, we believe the models are a bit too
aggressive with developing the heat across the region. The recent
rains over the last 6 weeks has led to a rather lush vegetation
cover over the area. In addition, it doesn`t appear that we`ll see
too much in terms of mixing given the rather large ridge aloft.
Thus, maximum temp numbers from the model guidance is likely some 3-
5 degrees too warm. Nonetheless, temperatures Thursday through
Saturday will be relatively hot with highs in the east topping out
in the lower 90s and in the mid 90s in the west/southwest. Dewpoints
will remain in the 70s which may allow us to briefly flirt with heat
advisory criteria in the western sections by Friday and Saturday
As previously mentioned, model verification stats show that we`ve
seen a too much of a northern bias in the storm tracks of late.
Essentially, the models have forecast more ridging than has actually
occurred. In addition, the models have always tried to expand the
ridge, but we`ve seen a constant theme here with the ridges breaking
down after a few days and the heat ridge being pushed further west
keeping the Ohio Valley in a notorious NW flow. For this reason,
we are going to keep isolated-scattered storm chances in for the
weekend and into early next week. Overall global pattern and
teleconnection pattern suggests we`ll see heights once again lower
over the eastern US yielding to cooler conditions as we head into
early next week.
.AVIATION (00Z TAF Update)...
Issued at 645 PM EDT Tue Jul 19 2016
North winds will go light/variable or even calm shortly after
sunset, with VFR conditions for most of the night. Only exception is
BWG, where MVFR visibilities will be possible early Wed morning
based largely on a persistence forecast. Could see IFR at times, but
not expecting vis to stay down more than a few minutes at a time, so
will leave that out for now. MOS guidance suggests LEX could also
see some restrictions, but given the drier air that worked in there
today and the lack of recent fog in the face of pessimistic
guidance, will keep VFR there. Expect only a few diurnal cu during
the afternoon, with light E-NE winds.