839
FXUS63 KPAH 020747
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
247 AM CDT Tue Jul 2 2024

.KEY MESSAGES...

- Dangerous heat and humidity levels are expected Wednesday and
  could develop over portions of the region on Thursday as well.

- Scattered to numerous thunderstorms are forecast at times from
  late Tuesday night through Friday evening. Some of the storms
  could be severe Wednesday afternoon and evening. Heavy rain
  and isolated flash flooding will also be concerns.

- Drier, less humid, and cooler weather is forecast for the
  weekend.

- Daily chances of thunderstorms are forecast for the first half
  of next week, and temperatures will be near normal.

&&

.DISCUSSION...
Issued at 247 AM CDT Tue Jul 2 2024

High pressure aloft is building over the Quad State early this
morning, but according the 00Z guidance it will quickly be
suppressed back to the south of the region by late tonight and
Wednesday. The upper trough moving eastward across Ontario
tonight and Wednesday is forecast to be a bit stronger with more
energy farther south. This works on the ridge and allows
convection to survive farther south as early as the pre-dawn
hours tonight/Wednesday morning.

The current thinking is that convection will make it into our
northwest zones well after midnight tonight and then push over
most of southeast Missouri, southern Illinois, and possibly
southwest Indiana before dissipating by midday Wednesday. The
residual outflow boundary or differential heating boundary will
likely focus thunderstorm development Wednesday afternoon and
evening. This development would be most likely over the
northwest half of the area in the afternoon and then push
eastward over the remainder of the area Wednesday night.

The next upper storm system will be stronger and farther south.
This will bring another round or two of thunderstorms through
the area at some point Thursday into Friday. It is forecast to
push a cold front eastward through the entire Quad State Friday,
which will bring an end to the convective activity.

Moderate to strong instability will be available across the
region on Wednesday. Wind fields will not be totally pathetic,
but will still struggle to organize convection. A few strong to
severe storms with damaging winds will be possible throughout
the region. Depending on how much heating occurs on Thursday, a
severe storm or two could be possible again then.

Precipitable water values will be around 2", which will support
torrential rainfall. There is a chance that the main convective
boundary will become oriented parallel to the zonal flow aloft
leading to training potential. All in all, the chance of some
portion of the area seeing some significant flash flooding seems
to be increasing, especially Thursday into Friday, presumably
after the area has already endured one round of heavy rainfall.

For today through Friday, the GEFS and ECENS both indicate
highly anomalous upper ridging and low-level moisture in our
vicinity. However, after the cold front passes Friday, they
indicate a near normal state of the atmosphere for the weekend
into next week.

The NBM is now indicating a dry weekend, but general troughing
aloft will persist through the weekend and into next week.
Eventually, more energy will drop into the trough and bring more
chances of storms. NBM PoPs begin Sunday night and continue
through next Tuesday, but they are 50% or less which seems
reasonable given the situation.

Temperatures today will climb up to near 90 throughout the
region, but the humidity albeit increasing, will not be
significantly disgusting to impact heat indices. However,
humidity along the lines of last Saturday will return on
Wednesday, with temperatures climbing toward the middle 90s.
This bring heat indices to 105 or greater over most of the
region. A Heat Advisory will likely be needed for Wednesday.
Thursday certainly could be hot and humid again, but confidence
is low given the expected convection. Beginning behind the front
on Friday, temperatures will generally be within a degree or two
of normal each day through next Tuesday.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 423 PM CDT Mon Jul 1 2024

Surface high pressure will move east from the Great Lakes to New
England. In response, winds will veer and return flow
southerlies will commence again starting tmrw. Satellite and
time/height cross sections suggest the dry air in the lower half
of the column remains strong for another package, so just some
occasional upper ridge topping mid to high level SCT-BKN bases
are expected.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.

&&

$$

DISCUSSION...DRS
AVIATION...DH