Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 200501
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
101 AM EDT Sun Jul 20 2014
...Updated Aviation Discussion...
Issued at 1045 PM EDT Sat Jul 19 2014
Quick update to match forecast grids with ongoing observations.
Radar has quieted down some more, but would not be surprised to see
some more light rain showers and or mist pop up through the night.
Also have light enough winds that if areas see some breaks in the
cloud cover, patchy fog would develop.
.SHORT TERM (Now through Sunday Night)...
Issued at 312 PM EDT Sat Jul 19 2014
Isolated showers and patchy drizzle will continue across the region
this afternoon as an upper level trough slowly shifts eastward. The
radar looks to overshooting the precipitation on the fringes of the
forecast area and precipitation rates are fairly efficient today.
Another trough will approach the area overnight and move through
tomorrow. Showers will develop again overnight as this next wave
approaches. These will be rather isolated in nature. The area of
showers will shift eastward through the day tomorrow with drying
conditions expected by tomorrow evening. As an upper level ridge
begins to build in from the west tomorrow night we should see dry
The other concern overnight will be the potential for some patchy
fog tonight. Winds will become light to calm and temperatures will
drop to the lower to mid 60s. Cross sections show ample low level
moisture will remain, so think some areas will see patchy fog,
similar to this morning.
Temperatures will be a bit warmer tomorrow, rising into the lower to
mid 80s. Lows tomorrow night will drop into the mid to upper 60s.
.LONG TERM (Monday through Saturday)...
Issued at 245 PM EDT Sat Jul 19 2014
The long term period will begin with upper level ridging working
into the area for Mon/Tues. This will cause a return to summer like
conditions with temps rising into the upper 80s and lower 90s for
highs. Some afternoon showers/storms may be possible east of I-65
farthest away from the ridge axis/capping and near a possible weak
sfc boundary, but even in these locations the cap may be too tough
to break for any convective development. Therefore will keep POPs
in the 20-30% range for now. POPs may need to be removed completely
if the latest model guidance is correct on the strength and eastward
extent of the ridge.
Wednesday will be the hottest day as the ridge maxes out over our
area before being replaced by an upper trough and cold front diving
south into the Midwest late in the day. High temps Wed should reach
solidly into the lower 90s. The cold front will bring showers and
storms to the region mainly Wed night according to the latest model
guidance. This could prove to be an interesting set up with good
instability building over the region for the first half of the week
followed by a decent cold front dropping south into the Ohio
Valley. An organized complex of storms could develop Wed night with
some of those becoming potentially strong in nature. Storms should
exit the area Thurs morning with temps and humidity levels dropping
off to below seasonal normals once again.
Friday looks to be a dry day but storm chances will again return for
the weekend as we sit in an active northwest flow. Temps will
likely remain below normal through the weekend with general
troughiness over the Midwest.
.AVIATION (06Z TAF Update)...
Issued at 100 AM EDT Sun Jul 20 2014
A rather unusual pattern for mid July continues across the Ohio
Valley early this morning, as unseasonably cool air is colliding
with a moist airmass, leading to low stratus and light fog. IFR
cigs have already built into KBWG and KLEX, and these will likely
lower through the remainder of the overnight hours. Given the
generally calm winds, think these cigs will continue to lower a
few hundred feet which will put both KLEX and KBWG into LIFR
conditions. The potential for IFR cigs is not quite as high over
at KSDF, as they did not receive measurable precip today and
slightly drier air has worked in. Therefore, will leave IFR cigs
out, but there still may be a period of fuel-alternate stratus for
a couple hours on either side of dawn.
As was the case yesterday, these cigs will be slow to lift through
the day today as mixing will remain limited. Conditions will return
to VFR first at KSDF, with KBWG and KLEX likely not mixing out into
VFR cigs until the afternoon hours. Winds will remain light and
variable through the day.