Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 08/18/19

Area Forecast Discussion

National Weather Service Louisville KY

 953 PM EDT Sat Aug 17 2019

.Forecast Update...
Updated at 953 PM EDT Sat Aug 17 2019

Have been keeping an eye on strong to severe storms that have blown
up in southern Illinois over the past few hours. It appears that
these storms and other overnight convection should stay to the west
and north of southern Indiana and central Kentucky closer to better
instability and low level jetting.

&&

.Short Term...(This evening through Sunday)
Updated at 240 PM EDT Sat Aug 17 2019

Near-term models today have handled this afternoon`s convection
poorly, especially when compared to how the overnight models and
even yesterday`s runs. AMDAR sounding out of Louisville now showing
a little bit of airmass modification in the 900-600 mb
layer...enough so to justify the more unstable airmass causing the
storms just to the west/left of the Ohio River and the lack of
convection to the east/right. Will continue to see isolated to
widely scattered storms develop the rest of the afternoon hours,
mainly along and north of I-64...again as that airmass modification
goes on...but soon cloud cover will start to limit available
instability.

All activity should shut down with that loss of instability and then
sunshine this evening. Another mid-level disturbance is forecast to
cross the Midwest late tonight, but this one should be far enough
north of our region to keep the storm track well north of us. That
more northern track, accompanied by a more southwest wind tomorrow
could push our temperatures to the warmest of the season so far.
Heat indices won`t be as high as during the July spell, but they
still will top out around 100 degrees for many locations.

.Long Term...(Sunday night through Saturday)
Updated at 222 PM EDT Sat Aug 17 2019

The upper level pattern going into Monday will feature a large ridge
building into the southern Plains and modest zonal flow over the
upper Midwest into New England. Upper level flow will be relatively
weak over most of our region and devoid of any notable shortwaves
and/or disturbances. This should result in a hot and mostly dry
forecast.

A strong, upper level trough will begin digging into the eastern
CONUS on Tuesday and force the Plains ridge to retrograde some to
the west. A surface cold front associated with the trough will begin
approaching the region on Wednesday. This will result in a period of
unsettled weather with increased shower and storm chances. Showers
and storms could linger into Thursday and Friday depending on how
quickly the front moves through, though chances for any
precipitation that late in the week would likely be confined to
southern Kentucky. Slightly cooler temperatures and lower dewpoints
will then move in behind the front.

&&

.Aviation...(00Z TAF Issuance)
Updated at 729 PM EDT Sat Aug 17 2019

VFR conditions expected throughout this TAF cycle as surface high
pressure sits over the Ohio Valley. Expect light southerly winds
overnight with intermittent cirrus streaming through the region.
With HNB having received a bit of rain earlier, there is a chance
that some brief MVFR vis could occur near sunrise. But no model data
is suggesting this as boundary layer winds are projected to be
strong enough to prevent any fog development. Have decided to leave
any mention of reduced vis out of HNB`s TAF, but will keep an eye on
this for future TAF issuance. Sunday afternoon will see winds pick
up out of the southwest with gusts in the upper teens possible at
SDF and HNB.


&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&

$$

Update...13
Short Term...RJS
Long Term...DM
Aviation...CG