Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 302328
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
728 PM EDT Sat May 30 2015
...Updated Aviation Discussion...
.SHORT TERM (Now through Sunday Night)...
Issued at 215 PM EDT Sat May 30 2015
As of mid afternoon, surface analysis shows an area of low pressure
near St Louis with an upper level shortwave trough across northern
Arkansas and southern Missouri. After a clean morning, afternoon
readings in the mid/upper 80s combined with dewpoints in the
mid/upper 60s and weak lapse rates yielded SBCAPE of about 1500 J/kg
across central KY and southern IN. A belt of higher winds in the
mid/upper levels is resulting in effective shear of around 25 kts.
As a result, scattered pulse showers/storms have tracked south to
north through parts of the area.
For the remainder of this afternoon and evening, plan on
showers/storms to continue to intermittently track through the area
until instability wanes with the loss of daytime heating.
Environment does support a few stronger storms but organized severe
weather risk is low at this point (higher to our west/northwest).
Main threat would be heavy rainfall and gusty/damaging winds.
Later this evening the low passes to our north and we`ll see showers
dissipate west to east. Wrap around clouds are expected to begin to
push in overnight, along with slightly cooler air. Lows tonight will
vary from upper 50s to low 60s in the northwest, to the mid/upper
60s across the southeast, Lake Cumberland region.
Sunday`s temperatures and precipitation forecast a bit more tricky
as we`ll have low clouds/stratus impacting parts of the area. This
should keep highs in the upper 60s to 70s, especially across
southern IN and northern KY, notably cooler compared to recent days.
However, the front will likely hang up across the KY/TN border and
as another upper wave passes, scattered afternoon showers/storms
will be possible. Thinking that the coverage and chances will be
comparatively lower than today, so kept POPs in th 30-40 percent
range. Across those areas, temperatures may rise into the upper 70s
to near 80 as well.
.LONG TERM (Monday through Saturday)...
Issued at 305 PM EDT Sat May 30 2015
Models have slowed the timing a little with upper trough becoming a
closed low to our west at the start of the period. With the earlier
slowing, the band of precip also looks to stick around longer than
the models were forecasting 12 hours ago. As this is a sudden
chance, do not want to go all in for a high pop forecast for the day
Monday and even Monday night. Thus have capped pops at 30% right
along our southeastern border Monday and 20% in our east Monday
night. Both periods should be cool with highs 5-10 degrees below
The slower solution becomes a problem further into the week as well,
and have a small chance for showers again just in our east for now.
Temperatures should remain below normal for Tuesday as well, and the
forecast beyond that still has a low confidence based on these
difficult to forecast closed low locations. For now have continued
the thinking of a warmer end to the work week with a little better
chance for diurnal showers/storms areawide.
.AVIATION (00Z TAF Update)...
Updated 728 PM EDT Sat May 30 2015
Numerous strong thunderstorms are currently heading toward BWG,
impacting the terminal around the top of the hour. Expect a period
of very heavy rain and gusty SW winds between 35-45 mph.
Scattered showers and storms will then push east through the evening
ahead of a mid level disturbance. Expect coverage to wane a bit with
the loss of heating so will only mention shower activity at SDF
(before 3 AM EDT) and LEX (2 AM to 6 AM EDT).
A surface low will then track just NNE of SDF around dawn on Sunday
with showers shutting off through the morning hours and winds
veering more SW. Will continue to advertise lower ceilings toward
dawn, potentially into the IFR category as some hi-res would
suggest. For now, will continue to mention below fuel-alternate at
SDF/BWG, and just into the MVFR range at BWG.
Surface low passes to the NE tomorrow, with winds continuing to veer
around to the W and then NW. Ceilings should gradually improve by
late morning early afternoon, with showery activity most likely at