494
FXUS63 KTOP 111854
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
154 PM CDT Thu Jul 11 2024

.KEY MESSAGES...

- A few strong storms possible this evening south of the Turnpike.

- Heat increasing this weekend, heat indices of 105-108 possible
Sat/Sun/Mon.

- Next widespread precip chances come Tuesday night with cold front.

&&

.DISCUSSION...
Issued at 154 PM CDT Thu Jul 11 2024

This afternoon, a low amplitude shortwave trough was located over
western Iowa, and was rotating around the base of a larger upper-
level trough over the Great Lakes. At the surface, there was
cyclonic flow around a low pressure centered over south central
Kansas, with a convergent boundary extending to the east towards
Springfield, MO. As the upper level forcing acts on the surface
boundary, thunderstorms will have a chance to develop in
southeastern Kansas. There is a marginal risk for severe
thunderstorms, as the stronger storms will have a threat for
damaging winds and large hail. Surface based CAPE of around 2000
J/Kg with effective shear around 30 knots suggests that storms are
not likely to be well organized. However, dry air aloft will lead to
DCAPE values around 1500 J/Kg, leading to a damaging wind threat.
With a strengthening low level jet and strong elevated instability,
large hail will also be possible in the stronger cores.

After that impulse moves through, Kansas will begin clearing out
overnight and into tomorrow. Unfortunately, there is no cold front
attached to the system, and the heat will only ramp up through the
weekend. Tomorrow, high temps will range from 94-100, with the
higher temps in central Kansas. With dewpoints around 70, most areas
can expect heat indices around 100.

500 hPa heights will increase through the weekend as the western
ridge strengthens. As a result, thunderstorm chances will drop this
weekend, and the temperature will rise. Southerly flow will be
advecting moisture into the area, and close to the KS/MO border,
dewpoints near 70 and temperatures near 100 will be commonplace.
Further west, stronger mixing will keep dewpoints closer to 60, but
temperatures will be closer to 105. The result is that most of the
area will see heat indices between 105 and 108 from Saturday through
Monday. Max temperatures for Sunday and Monday were slightly
adjusted, due to the GFS showing its hot bias, nearly 6 degrees F
above the other global models in some spots.

It appears that the next big trough/frontal boundary will push
through the area some time between Tuesday and Wednesday, with the
GEFS mean showing Tuesday in the overnight period. This will come
with another shot of precipitation along the front in the form of
thunderstorms. Widespread precip and cloud cover should keep
temperatures down for Wednesday, with the current forecast showing
more seasonal temperatures in the upper 80s.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1142 AM CDT Thu Jul 11 2024

VFR conditions will prevail through the TAF period. East winds will
remain just under 10 kt through today and tonight, diminishing some
after dark. After sunset, there is a 20-30% chance of scattered
showers and storms, mostly for TOP/FOE. Coverage will be low, and
confidence was not high enough to include. Tomorrow morning, winds
will pick up out of the SE, and will increase to 8-10 kt.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Montgomery
AVIATION...Montgomery