000
ACUS02 KWNS 230526
SWODY2
SPC AC 230525

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1225 AM CDT Mon Sep 23 2019

Valid 241200Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER EASTERN
NEBRASKA...IOWA...SOUTHERN MINNESOTA...AND WESTERN WISCONSIN...

...SUMMARY...
Severe storms are possible Tuesday across much of Iowa, western
Wisconsin, eastern Nebraska, and southern Minnesota, with isolated
storms from parts of the central Plains to the Upper Great Lakes. A
few strong storms may linger over southern Arizona as well.

...Synopsis...
Strong cyclonic flow aloft will broaden over the north-central U.S.
with the nose of an upper level jet developing across the Dakotas,
MN, and WI. Cooling aloft will coincide with this jet max which will
work with a cold front to provide a focus for severe storms. The
front will stretch roughly from southern MN into eastern NE by 00Z,
with increasing low-level moisture aiding destabilization. The tail
end of this front will stall over KS, where a moist and unstable air
mass will remain.

To the west, an upper low will continue dropping south across
western AZ and into the northern Gulf of CA, with cool temperatures
aloft and antecedent moisture maintaining a risk of thunderstorms
mainly over southern AZ.

...IA/MN/WI area, and NE/KS...
Southwest surface winds will increase throughout the period, with
30-40 kt at 850 mb aiding moisture transport ahead of the cold
front. At least mid 60s F dewpoints are expected to spread north
into southern MN, with upper 60s F possible depending on
evapotranspiration and mixing. This should yield at least 2000 J/kg
MUCAPE, with steep lapse rates aloft. Storms are expected to form
late in the day along the front where the cap will be breached due
to lift. The increasing west/northwest winds aloft will result in
favorable shear vector orientation along the front for supercells, a
few of which may produce very large hail. A tornado or two is
possible as well with effective SRH increasing above 200 m2/s2. The
main limiting factors to an Enhanced Risk category are expected
storms coverage due to capping and boundary layer moisture quality.
Isolated severe storms are possible as far southwest as eastern
Nebraska along the front, where dewpoints are likely to be higher,
though large-scale lift will not be as favorable. Isolated severe
storms capable of hail or wind may also occur over central KS during
the afternoon as heating will be strong over southwest KS ahead of
the boundary. A storm or two may approach northern OK during the
evening.

...Southern AZ...
Scattered thunderstorms are likely to be ongoing over parts of
southern AZ, and cool temperatures aloft may support a few strong
storms with gusty winds or small hail. Additional storms cannot be
ruled out during the afternoon with heating, while temperatures
aloft remain cool. By this time, shear will be weaker, thus
widespread severe is not expected.

...MAXIMUM RISK BY HAZARD...
Tornado:   5%     - Slight
Wind:     15%     - Slight
Hail:     15% SIG - Slight

..Jewell.. 09/23/2019

$$