SPC Oct 28, 2026 2000 UTC Day 1 Convective Outlook
SPC 2000Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 PM CDT Wed Oct 28 2026

Valid 282000Z - 291200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
EASTERN MINNESOTA INTO NORTHWEST WISCONSIN...

...SUMMARY...
A few severe thunderstorms may occur over parts of Minnesota and
Wisconsin this afternoon and early evening. Isolated tornadoes,
severe hail, and damaging winds will be possible.

...20z Update...
A loosely organized cluster of cells has developed across portions
of west-central Minnesota, the strongest of which produced some
severe hail. These storms developed along the nose of low-level
warm/moist air advection and will continue spreading northeast into
portions of central and east-central Minnesota. See MCD #2413 for
additional details.

Farther south, destabilization has occurred across portions of far
southwest Minnesota and northwest Iowa. Continued low-level
warm/moist air advection and vertical mixing has allowed surface dew
point temperatures to reach the low 60s F. This, along with filtered
insolation is yielding MLCAPE values near 1000 J/kg. Broad ascent is
now overspreading this region, associated with the right-entrance
region of the upper-level jet and an approaching mid-level
short-wave trough. Additionally, visible satellite shows areas of
developing cumulus near the IA/MN border amid a pocket of reduced
CIN per the latest surface mesoanalysis.

Given these conditions, storms are still expected to initiate and
spread northeast, mainly into south-central Minnesota initially.
However, considerable uncertainty exists in the ensuing convective
mode(s). The aforementioned destabilization combined with ample
low-level shear will support a tornado threat if a storm or two can
acquire supercellular characteristics. As such, tornado/wind
probabilities have been maintained. Any such storm will be
accompanied by the threat for severe hail. Therefore, 15% hail
probabilities have been added, covering the preexisting Level 2 of 5
(Slight) risk area.

Elsewhere, the balance of the previous forecast remains on track.
See the discussion below for more details.

..Karstens/Thompson.. 10/28/2026

.PREV DISCUSSION... /ISSUED 1120 AM CDT Wed Oct 28 2026/

...Upper Midwest...
Within a zone of enhanced southwesterly mid-level flow across the
north-central CONUS, a shortwave trough over the northern High
Plains late this morning will advance east-northeastward towards the
Upper Midwest this afternoon/evening. A related surface low over the
central High Plains will likewise develop northeastward to
south-central MN by mid afternoon, with a trailing cold front
extending southwestward across the northern/central Plains. Latest
surface observations and observed 12Z soundings across the Upper
Midwest/central Plains show limited low-level moisture present in
the warm sector (surface dewpoints generally in the mid to upper
50s). This will tend to hinder the development of any more than weak
instability (MLCAPE generally 500-1000 J/kg, perhaps locally
stronger southward in IA ahead of the cold front), even as surface
temperatures continue to warm into the 60s with filtered diurnal
heating.

Strengthening low/mid-level winds through the afternoon will easily
support favorable veering wind profiles with height and around 30-40
kt of deep-layer shear. This shear, coupled with potentially
sufficient boundary-layer instability, may support a narrow zone of
severe potential with thunderstorms that develop near/just east of
the surface low across southern/eastern MN into northwest WI this
afternoon. Even with neutral lapse rates/saturated low-level
profiles depicted across this region per recent RAP forecast
soundings, the presence of elongated/curved low-level hodographs may
still support some risk for a couple of tornadoes with any
supercells that can become established and remain surface based.
Otherwise, isolated severe hail and damaging winds also appear
possible as convection spreads quickly northeastward through the
late afternoon/early evening before weakening with the loss of
daytime heating. Some of this activity may become slightly elevated,
but it could still pose some hail/gusty wind threat.

The potential for robust thunderstorm development farther south into
IA and eastern NE along/ahead of the cold front remains uncertain,
as large-scale ascent will be weaker with southward extent across
this area. If convection can initiate and persist, then occasional
hail could occur with the strongest cores. Have maintained the
Marginal Risk across this region for this rather conditional
possibility.

...Far West Texas/Southeast New Mexico...
A strong thunderstorm or two appears possible again this afternoon
along/east of the Guadalupe Mountains of southeast NM and the Davis
Mountains in far west TX. Forcing for ascent will remain weak, and
overall thunderstorm coverage should remain rather isolated.


Read more
https://www.spc.noaa.gov/products/outlook/day1otlk_2000.html