125
FXUS63 KTOP 031948
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
248 PM CDT Fri May 3 2024

.KEY MESSAGES...

-A line of thunderstorms is expected to move from west to east
 across the area tonight into early Saturday morning. There is
 a low chance for a few damaging wind gusts.

-A better chance for severe weather arrives Monday afternoon as
 a stronger system impacts the central US. All modes of severe
 weather will be possible.

&&

.DISCUSSION...
Issued at 240 PM CDT Fri May 3 2024

This afternoon, a shortwave trough is evident on water vapor
imagery over Wyoming with southwest flow over KS. Surface obs
show high pressure centered in eastern Iowa. South-southeast
winds are beginning to transport higher dew points back into the
area, which will continue as high pressure slides further
northeast and low level flow increases this evening. The
shortwave over WY will move eastward across the Dakotas this
evening and tonight, bringing a cold front across KS. A linear
complex of thunderstorms is expected to develop in western
Nebraska/Kansas near the boundary this evening, marching
eastward into tonight. Instability will initially increase in
eastern KS with the theta-e advection this evening, but CIN is
also expected to increase as the night progresses and the storms
approach. HREF MUCAPE values range from about 1000-1500 J/kg
ahead of the front, with storms likely along or just behind the
instability gradient. Shear still looks to range from about
30-35 kts, helping to maintain storm structure aloft. Given
these parameters, strong winds and small hail will be the main
concerns with storms as they move through tonight.

Lingering post-frontal showers, and gusty northwest winds will be
possible through Saturday morning before high pressure brings in a
cooler and drier air mass. High temperatures Saturday afternoon look
to run about ten degrees cooler than today. Another shortwave trough
could then bring precipitation back to the forecast area, but
this time from the south. That trough will move across TX and
the Red River Valley, then into the Ozarks on Sunday.
Instability and moisture will be more limited, so severe weather
is not expected. Have also decreased POPs slightly with some
deterministic models now keeping most of the area dry. Still
think there is at least a slight chance for light QPF mainly
south of I-70.

A much stronger and more impactful system is still on track for the
Monday afternoon/evening timeframe. A deep H5 trough looks to move
across the Rockies and take on a negative tilt as it progresses over
the High Plains Monday afternoon. Strong southerly flow will quickly
transport moisture into the region ahead of a deepening surface low.
Instability will build in the warm sector across central and eastern
KS in response, with models showing anywhere between 2000-3500
J/kg of SBCAPE. With effective bulk shear possibly exceeding 40
kts and 0-3 km SRH above 200 m2/s2, another round of severe
weather is anticipated. All modes will be possible, including
damaging winds, large hail and tornadoes.

Severe weather is not currently expected for the rest of next week,
but a series of shortwave troughs embedded the the flow aloft could
at least keep some POPs around through midweek.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1238 PM CDT Fri May 3 2024

Cloud cover will increase this afternoon. A few models are
showing MVFR conditions, while others are not. Have kept VFR
conditions through the afternoon for now, but will amend if CIGS
are lower than currently expected. TS will be the next concern
as a line of storms is expected to impact airports late
tonight/early Saturday morning. Timing may need to be tweaked
slightly, but current thinking for impact timing is the 09-12Z
timeframe as storms move from west to east across the area. Wind
gusts to 30kts can`t be ruled out with storms, with isolated
higher gusts. Lingering MVFR CIGS could occur through the
morning hours before VFR returns late this period.

&&

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

&&

$$

DISCUSSION...Teefey
AVIATION...Teefey