650
FXUS63 KPAH 242328
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
628 PM CDT Mon Jun 24 2024

.KEY MESSAGES...

- A Heat Advisory is in effect Tuesday afternoon for all but the
  southeast quadrant of the region, as heat indices are expected
  to reach 105 degrees or greater.

- Chances of thunderstorms are forecast Tuesday afternoon
  through Wednesday evening. A stray strong to severe storm is
  possible with gusty winds the main threat.

- After a brief respite from the heat and humidity Thursday,
  heat indices will climb well above 100 degrees throughout the
  area Saturday. Another round of thunderstorms is possible
  sometime between Friday night and Sunday.

&&

.DISCUSSION...
Issued at 302 PM CDT Mon Jun 24 2024

We have expanded the Heat Advisory eastward through the Purchase
Area, through much of southern Illinois and into the Evansville
area in Indiana. NBM temperatures and dewpoints yield 105 degree
heat indices in these areas, with the worst conditions expected
in the original Advisory area. Outside of the Advisory, heat
indices will be 100 to 105 degrees. There is some potential that
convection late tonight and Tuesday morning could prevent the
extreme heat and humidity from developing, but confidence is
not great enough to alter our thinking for the Heat Advisory.

A large MCS is expected to surge eastward through the western Great
Lakes tonight. Warm advection ahead of it could squeeze out a
few showers tonight in the north as the GFS shows, but the
chance is too low to mention in the forecast at this time. The
bigger concern is the potential for an outflow boundary to sag
close enough to the region to focus thunderstorm development
Tuesday afternoon, mainly over southern Illinois and southeast
Missouri. The larger-scale cold front will push through the
entire area Wednesday, bringing an end to the extreme heat and
convective chances.

Instability Tuesday will be strong and could also be healthy
ahead of the cold front Wednesday, if the environment has not
been muddled by previous convection. Wind fields will be weak,
so we will be looking at pulsy storms with some limited
potential for damaging winds. Severe storms will be most likely
in the heat of the day both days. Confidence in the timing
details of convection Tuesday through Wednesday is not great.

We should have a very nice dry day Thursday with lower
temperatures and humidity. South winds will return on Friday and
temperatures will climb back into the lower 90s. Southwest winds
will bring very humid air across the region for Saturday, when
heat indices will be in the 105-110 range for the entire area.

There are similar convective concerns Friday night through the
weekend as we discussed for the mid-week front, but the upper
ridge will be stronger and could keep most of the convection
north of the region through Saturday. Whenever convection can
develop across the Quad State this weekend, strong instability
with relatively weak wind fields will likely keep the severe
threat at marginal levels with mainly a damaging wind threat.

It appears that a cold front will eventually pass through the
Quad State sometime Sunday or Sunday night, so next Monday
should be another pleasant day.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 628 PM CDT Mon Jun 24 2024

VFR forecast tonight and Tue. Winds will increase from the SW
Tue morning with some gusts near 20 kts by the afternoon. Very
low chance of a storm or two Tue afternoon and kept the mention
out of the TAFs for now.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Heat Advisory from noon to 8 PM CDT Tuesday for ILZ075>078-
     080>086-088>090-092>094.
MO...Heat Advisory from noon to 8 PM CDT Tuesday for MOZ076-086-087-
     100-107>112-114.
IN...Heat Advisory from noon to 8 PM CDT Tuesday for INZ081-085-086.
KY...Heat Advisory from noon to 8 PM CDT Tuesday for KYZ001>009.

&&

$$

DISCUSSION...DRS
AVIATION...AD