ACUS11 KWNS 081949
SWOMCD
SPC MCD 081949
IAZ000-NEZ000-082145-

Mesoscale Discussion 2270
NWS Storm Prediction Center Norman OK
0249 PM CDT Tue Sep 08 2026

Areas affected...portions of extreme eastern Nebraska into central
Iowa

Concerning...Severe potential...Watch possible

Valid 081949Z - 082145Z

Probability of Watch Issuance...60 percent

SUMMARY...Thunderstorms should gradually increase in coverage and
intensity as a surface cold front approaches. The strongest storms
may be accompanied by at least a few severe gusts and perhaps a
tornado or two. Convective trends are being monitored for the need
of a WW issuance.

DISCUSSION...A relatively broad swath of precipitation is currently overspreading central NE into the northern half of IA, ahead of a
surface cold front, which has limited insolation and boundary-layer destabilization across much of the region thus far. However, ample boundary-layer mixing is underway to the southern periphery of this
rain band, where surface temperatures have heated into the 90s F (to
near 100 F in some spots). Given low to mid 70s F surface dewpoints,
MLCAPE has boosted to over 2000 J/kg despite mediocre mid-level
lapse rates.

It is unclear precisely when storms will initiate since much of the
available deep-layer ascent will glance the region to the north.
Nonetheless, a pre-frontal trough is gradually drifting east across
far southeastern NE, and this boundary may serve as a potential
focusing mechanism for more robust surface based thunderstorm
development over the next few hours. Storms may initially be
semi-discrete and anafrontal in nature. As the storms mature, and
assuming they can propagate into the warm sector, then surface-based
convection will become possible. These storms would most likely
become an MCS capable of producing a few severe gusts and perhaps a
couple of QLCS tornadoes.

A Severe Thunderstorm Watch may be needed when convective initiation
and intensification become more apparent.

..Squitieri/Hart.. 09/08/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!63bzBlHU7s82QU_b_7ttPiXc9LxDiioiweVTYAoEDoepHDv_Phd29c2GPkCNCCasAyx-lzrB2fTx1BkBSTY61dg2axo$ for graphic product...

ATTN...WFO...DVN...DMX...OAX...

LAT...LON 41149681 41829577 42539383 42569145 42379101 41649098
41089215 40769469 40649550 40599628 41149681

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


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