Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 280710
Area Forecast Discussion
National Weather Service Louisville KY
310 AM EDT WED SEP 28 2016
.SHORT TERM (Now through Thursday)...
Issued at 250 AM EDT Wed Sep 28 2016
A strong vort max will enter the region today as a deep upper low
and cold front dive south into the Ohio Valley. This weather system
will kick off low topped convection this morning after sunrise in
southern IN with convection expanding and pushing ESE through
central KY during the afternoon/early evening hours. Model
soundings are supportive of small hail and gusty winds in the
stronger cells this afternoon/early evening. Of particular interest
is an area from Louisville/Lexington and points northward where a
good pocket of instability is progged to develop providing an area
of enhanced energy for hail/wind production. Will need to watch
this region for strong storms possibly approaching severe limits.
Quite the gradient of temps are expected today as convection and the
cooler airmass limits highs over southern IN/north central KY to the
upper 60s while south central KY warms into the mid 70s.
Tonight expect convection to diminish in coverage with the loss of
day time heating. However, will still keep 20-30% POPs overnight as
lobes of vorticity continue to rotate around the upper low sparking
some convection. Lows will dip into the upper 40s and lower 50s.
For Thurs, expect convection to increase in coverage and strength
with isld storms possible during the afternoon/early evening hours.
Small hail and gusty winds will again be possible with any
convection. However, with a thick cloud cover anticipated for much
of the day, CAPE values may remain lower than today limiting hail
sizes/gusty wind potential. With the cold core directly over central
KY, temperatures will be limited to the low to mid 60s.
.LONG TERM (Thursday night through Tuesday)...
Issued at 310 AM EDT Wed Sep 28 2016
Thursday Night - Saturday...
The upper low will maintain its influence over the Ohio Valley
through the end of the week. As it wobbles over our region, expect
continued rounds of showers with isld t-storms possible mainly
during the afternoon/early evening hours. Convection will increase
in coverage with any one particular vort lobe rounding the upper low
and during peak heating each day. Did omit t-storm chances Sat
afternoon as the upper low will begin to weaken and pull away to our
north leaving only limited forcing.
Temps will hold in the mid 60s to around 70 for highs both Fri/Sat.
Overnight lows will range from the upper 40s to mid 50s.
Sunday - Tuesday...
Dry weather will return with a moderation in temps for the beginning
of next week as the upper low finally weakens and moves north into
the Great Lakes and southern Canada. Temps look to rebound into the
70s for Sun/Mon and then low 80s by Tues. Low temps should range
though the 50s.
.AVIATION (06Z TAF Update)...
Issued at 138 AM EDT Wed Sep 28 2016
Not much change in the ongoing forecast for aviation. Clear skies
will be present tonight with VFR conditions expected through sunrise.
Strong closed upper low still on target to dive southward into
Indiana this afternoon. Cloud cover will increase rapidly after
sunrise with a lowering ceiling setting in by afternoon.
Precipitation is expected to break out by mid-late morning across
southern Indiana and into northern KY and will impact the KSDF and
KLEX terminals. No restrictions expected initially, but as the rain
gets better established, look for MVFR visibility and ceilings,
albeit just above the fuel-alternate threshold. Winds come around to
the west and eventually the NW late in the afternoon, with gusts
just shy of 20 kt.
KBWG may not see much active weather in this forecast period given
its farther south relative position. Some VCSH will be possible at
KBWG after 28/21Z.