Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 130703
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
302 AM EDT MON MAY 13 2013
.Short Term (Now - Tuesday)...
Issued at 300 AM EDT Mon May 13 2013
So far the early morning has been a few degrees warmer than
expected, but lows still should bottom out in the mid/upper 30s,
save for KSDF, which likely will stay in the lower 40s. These temps
are enough to warrant leaving the frost advisory in place through
daybreak. With full sunshine at daybreak, expect temperatures to
warm up quickly. Increased 1000-850 mb thicknesses indicate highs
generally in the mid 60s, or roughly 10 degrees below normal for mid
Surface high bringing the nice weather today will shift into the
southeast U.S. tonight, allowing a warm front to move into our
region. We will see increasing clouds through the night as zone of
strong isentropic lift moves in. However limited moisture will mean
very low rain chances with this passage. Temperatures will be
coolest in the east, where it will take the longest for the clouds
to get in overnight. They should see readings in the low 40s, but
points west of I-65 look to fall only to around 50.
Temperatures will be noticeably warmer behind that front on Tuesday.
The only limiting factor will be how long cloud cover lingers in the
morning. Otherwise, we should see readings rocket up to the upper
70s over the Bluegrass and the lower 80s west of I-65.
.Long Term (Tuesday Night - Sunday)...
Issued at 300 AM EDT Mon May 13 2013
Surface high pressure across our area will shift south and east as a
low crosses the Upper Great Lakes Tuesday night and Wednesday. A
frontal boundary trailing the low will slide south, into central
Illinois, Indiana, and Ohio. This is where the front will stall late
Wednesday and Thursday. Flow aloft will be confluent, which will
allow showers and thunderstorms to continually develop and push east
along this stalled boundary. While Wednesday will be dry, rain
chances will increase through the week and into the weekend. Our
best chance of convection late Wednesday and into Thursday will be
across our northern CWA, generally southern IN and north-central KY.
Through the day Thursday, we should destabilize as a shortwave
trough passes to our north. Convection appears to either develop in
the afternoon or upstream morning convection along the stalled
boundary will propagate into our area. CWA-wide showers and
thunderstorms would be possible.
Temperatures Wednesday will top out in the lower and middle 80s with
breezy southwest winds. Temperatures Thursday should be several
degrees cooler with additional cloud cover, and especially with the
shower and thunderstorm potential. Overnight lows will drop into the
The quasi-stationary surface front seems to linger, which would
continue to be the focus for convection right on through the
weekend. However, model solutions diverge, which lowers forecast
confidence for the weekend. It appears we will see our chances of
showers and thunderstorms, probably in waves, Friday through Sunday.
It is extremely tough to time these waves at this point, but an
unsettled pattern is likely. As mentioned in the previous forecast
discussion, will be conservative with PoPs and QPF for now.
Temperatures Friday through Sunday should range between the upper
70s and lower 80s, with the boundary to our north. Overnight lows in
the lower and middle 60s will be common.
.Aviation (06Z TAF Issuance)...
Issued at 110 AM EDT Mon May 13 2013
Have a few passing high clouds as a large scale upper trough axis
crosses the region. Should see diurnal cumulus field develop during
the day along with increases winds from the west as high pressure
moves into the Deep South today. Winds will slacken again by late
afternoon, with high clouds increasing late this evening as a dry
warm front moves into the region.
IN...FROST ADVISORY UNTIL 9 AM EDT /8 AM CDT/ THIS MORNING FOR
KY...FROST ADVISORY UNTIL 9 AM EDT /8 AM CDT/ THIS MORNING FOR