Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 231924
Area Forecast Discussion
National Weather Service Louisville KY
324 PM EDT MON MAY 23 2016
.SHORT TERM (Now through Wednesday Night)...
Issued at 240 PM EDT Mon May 23 2016
High pressure sliding SSEwd from the central Appalachians through
the Carolinas will provide us with mostly clear skies, light winds,
and pleasant temperatures tonight and Tuesday. Lows tonight should
be in the lower 50s (cooler in the usual cool spots) with highs
tomorrow in the lower and middle 80s. Though dew points tomorrow
afternoon won`t be quite as low as they were today, they`ll still
probably mix down into the upper 40s, so the temperatures in the 80s
will be very bearable.
Tuesday night through Wednesday night moisture will continue to
increase in southerly low level flow. A couple of 5H vorts will pass
overhead on Wednesday as precipitable water values approach 1.5" and
surface dew points rise into the lower and middle 60s. However, the
best low level jetting Tuesday night will be well to our west over
the Plains, and on Wednesday night will reach from the Red River
Valley to the Great Lakes. The best mid and upper level jet energy
will also remain to our west. Not much in the way of a trigger at
the surface here as we sit well ensconced in the warm sector ahead
of low pressure over the central Plains and Midwest. So, we`ll stick
with just chance PoPs in the forecast to account for those waves and
the possibility of any leftover convection coming in from the west.
Highs Wednesday will be similar to what we see Tuesday but it will
feel much muggier.
.LONG TERM (Thursday through Tuesday)...
Issued at 323 PM EDT Mon May 23 2016
Thursday through Friday Night...
Latest multi-model consensus suggests that the ridge axis will be
east of the region by Thursday morning. At the beginning of the
period, it appears that we`ll have a weak perturbation moving
through within the southwesterly flow. This should promote
scattered showers and storms across the region...though it looks
like the best chances would be across the north/northwest sections
during the day and into the evening hours. Highs Thursday will
generally be in the low to mid 80s with overnight lows in the mid
A deep southwesterly flow will persist Thursday night and into
Friday as a fairly deep trough moves through the upper Midwest. Both
the GFS and Euro solutions suggest another perturbation to pass
through the region late Thursday and into Friday which will likely
produce another round of convection across our region. Again, it
appears that the most widespread precip may fall across our west and
northwest as our eastern/southeastern sections may see a bit more
protection from the ridge axis to our east. Friday will be warm
again with highs in the lower to mid 80s. The eastern sections may
see some upper 80s given that there may be lesser precipitation
coverage out that way. Scattered showers and storms may linger into
the evening hours with overnight lows dropping back into the lower-
Saturday through Memorial Day...
For this time frame, the model consensus is similar to the overnight
guidance in developing a more defined trough axis in the west while
propping up the eastern US ridge. This results in a very amplified
southwest flow pattern over our region which will have a nice plume
of gulf moisture with it. The main forecast challenge here is
trying to figure out the placement of the plume. Much of the model
consensus this afternoon keeps it to the west of region. Should this
be the case, then we`ll see more scattered convection during the
afternoon/evening...especially in our western sections with drier
and more isolated convection in the east. This thinking is similar
to the overnight data that suggested a slightly drier pattern.
However, if the plume shifts eastward, then more widespread
convection will be possible across the region. For now, have
continued the midnight shift trend of lesser coverage of showers and
storms across the region, but will keep the highest chances mainly
west of I-65.
Temperatures through the period will be dependent on cloud cover and
convective coverage. Some of the models have been suggesting highs
running at 90. However, this appears to be overdone given the lust
vegetation and generally moist soil conditions. In addition,
convective coverage and debris clouds would certainly curtail
afternoon highs. For now, have gone closer to the consensus raw
numbers for the period which results in afternoon highs of 83-88 and
overnight lows in the mid-upper 60s.
.AVIATION (18Z TAF Update)...
Issued at 1210 PM EDT Mon May 23 2016
High pressure sinking from Ohio to South Carolina will keep our
skies clear and winds light through the TAF period. Winds will pivot
from the northeast today to the southwest tomorrow as the high