Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 151845

Area Forecast Discussion
National Weather Service Louisville KY
245 PM EDT Sun Jul 15 2018

.Short Term...(This evening through Monday)
Issued at 215 PM EDT Sun Jul 15 2018

Latest water vapor loop showers a persistent east/west oriented band
of moisture over the Ohio Valley this hour. Best moisture is over
far western Kentucky, where some impressive storms are forming this
hour. These storms are progressing eastward, but the updrafts should
not be as strong as they move into a more stable surface
environment. Still cold pools from those storms should provide
enough lift for elevated storms to survive into our BWG zones late
this afternoon and evening. Given that this area already has seen
good rains today, will have to watch for flood potential.  Farther
northeast along the Ohio River, we are warming up slowly as cloud
cover starts to fade. We may see outflow boundaries sparking off new
storms here as well this afternoon/evening.

The upper troughiness slowly pushes east Monday, providing another
good shot at rain until we can get it east of our longitude in the
long-term period below. A cool front will provide some focus, but
again expect outflow boundaries from previous storms to ignite new
development also. As is the case today, high temperatures will
depend strongly on how often any one location gets rain. For now
have kept most locations in the mid to upper 80s.


.Long Term...(Monday night through Sunday)
Issued at 222 PM EDT Sun Jul 15 2018

Main weather highlights in the long term are pleasant, low humidity
for mid-week followed by a pattern change featuring a closed upper
level low over the eastern US.

A cold front will cross through the region Monday night into Tuesday
morning. Showers and storms will remain possible Monday evening but
look to become isolated overnight with the loss of daytime heating.
Tuesday will be the transition day between air masses and weather
pattern as the cold front eventually drops south of Kentucky by the
afternoon hours.  Showers and a few storms may linger across
southern Kentucky in the morning until the front passes through.
Highs look to top out in the 80s.

High pressure nosing down from the Great Lakes Wednesday will bring
refreshing dry air and will make for a very pleasant mid-July day.
Highs will reach the mid 80s under mostly sunny skies.

15.12z deterministic models in good agreement for the latter
portions of the week in terms of large scale features but still
have differences in timing, location, and smaller details. A strong
shortwave trough is expected to move through the Upper Midwest
eventually becoming closed and cut off Friday into next weekend
somewhere across the Great Lakes or Ohio Valley. This would bring a
period of unsettled weather with plenty of clouds and opportunities
for showers and thunderstorms. Additionally the increased cloud
cover would likely keep high temperatures down closer or even
slightly below normal.


.Aviation...(18Z TAF Issuance)
Issued at 135 PM EDT Sun Jul 15 2018

Complicated forecast continues this period, as multiple disturbances
ride over a juicy airmass to create good chances for showers and
storms. Tried to highlight the best chances in the short term for
now, given current trends, but new storms are popping up even behind
areas that recently received rains, so expect amendments. Overnight
we may be able to switch to just showers briefly, before the storm
threat returns again Monday morning, along with potential for some
lower ceilings.




Short Term...RJS
Long Term...ZT
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