Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 221047

Area Forecast Discussion
National Weather Service Louisville KY
647 AM EDT Sun Jul 22 2018

...Updated Aviation Discussion...

.Short Term...(Today and tonight)
Issued at 315 AM EDT Sun Jul 22 2018

The center of the anomalous upper low will wobble down into Kentucky
today and then down through east Tennessee later tonight. Slightly
deeper moisture (~1000-500mb) will accompany the feature and will
result in another mostly cloudy day. As we get through mid day and
then into the afternoon, diurnal trends should help spark shallow
convection over the area. Will keep the coverage in the 40-60%
range, with only an isolated chance at thunder. Instability profiles
look weaker today than they did for yesterday, and it appears that
was overdone as heating was limited by cloud cover. So, expect the
same trend for today to the point that thunder should be pretty
sparse. Overall, the best chance for rainfall amounts around a third
of an inch will be east of I-65, but keep in mind that not everyone
will see those amounts or even rain at all. West of I-65, most
amounts should be between a tenth and a quarter of an inch.
Convection will diminish in the evening once again, with pops
settling into the 20% range east of I-65 overnight.

Look for cool highs mostly in the 75 to 80 degree range today. Lows
tonight should settle into the mid 60s.

.Long Term...(Monday through Saturday)
Issued at 330 AM EDT Sun Jul 22 2018

Eastern half of the U.S. will remain under the influence of the
current upper low through Wednesday, though it slowly will fill in
each day. Another upper low then looks to move into the Great Lakes
and reinforce our cooler temperatures into the next weekend. In
between, for Wed-Fri, look for temperatures near normal for late
July. Given the lower heights aloft, and some moisture around, do
have rain chances for most of this long-term period, but no one day
of the week looks especially wet. By the weekend, we will have to
watch to see how far south a cool front, associated with the Great
Lakes system, makes it.  00Z GFS has the front stalling over the
region with a southwest flow aloft pumping in plenty of moisture.
Should this solution verify, we would see some pretty good rains.


.Aviation...(12Z TAF Issuance)
Issued at 647 AM EDT Sun Jul 22 2018

An upper level low will continue to drift south into the Ohio Valley
this forecast period. An MVFR stratocu deck has built over the
northern TAF sites this morning, below fuel alternate at SDF/LEX.
For the moment, seeing IFR at HNB and still think there is a chance
for IFR at LEX for a few hours after sunrise. SDF should stay more
in the 1200-1900 foot range this morning. Expect MVFR at BWG by the
valid time of this TAF issuance.

Look for a return to VFR by early to mid afternoon as the stratocu
deck breaks up. This will also be the best time for a scattered
shower to impact a TAF site. Instability will be hard to come by so
won`t include any mention of thunder, although a few strikes are
expected in the region.

Generally WNW winds this morning will become a bit stronger and NW
later today. Winds will slacken a bit and then become northerly by
late this evening. MVFR ceilings are expected to return again
overnight, with IFR a good possibility at LEX.




Short Term...BJS
Long Term...RJS
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