Mesoscale Discussion 1436
NWS Storm Prediction Center Norman OK
1105 AM CDT Thu Jul 02 2026

Areas affected...northern Iowa into far southwest Wisconsin

Concerning...Severe potential...Watch possible 

Valid 021605Z - 021730Z

Probability of Watch Issuance...40 percent

SUMMARY...The large hail/damaging wind threat will increase late
this morning and into the afternoon.

DISCUSSION...Storm coverage has recently increased along a frontal
boundary across northern Iowa this morning in response to an
approaching mid-level shortwave trough. SPC mesoanalysis indicates
the environment along and south of this front is nearly uncapped
with 2000 to 2500 J/kg MLCAPE. Ongoing storms are likely elevated,
but given continued heating, they may become surface-based in the
next 1 to 2 hours. Either way, there is sufficient MUCAPE in the
area. This instability, combined with 40 to 50 knots of mid-level
flow, will support a supercell threat late this morning and into the
early afternoon.

..Bentley/Hart.. 07/02/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MKX...DVN...ARX...DMX...FSD...

LAT...LON   42619503 43059478 43409402 43469305 43489102 43328999
            42589015 42299226 42239425 42359507 42619503 

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0743 AM CDT Thu Jul 02 2026

Valid 021300Z - 031200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE UPPER MIDWEST...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE DAKOTAS
INTO THE WESTERN GREAT LAKES AND OVER THE SOUTHERN APPALACHIANS AND
TENNESSEE VALLEY...

...SUMMARY...
Scattered to numerous severe storms will be possible from the
northern Plains into the Midwest and Great Lakes regions today into
tonight, as well as across the southern Appalachians and Tennessee
Valley this afternoon and early evening.

...Northern High Plains into the Great Lakes and Midwest...
A belt of moderate southwesterly flow will extend across the
north-central states through the period.  A few ongoing clusters of
showers/thunderstorms extend along residual outflow from WI to along
the MN-IA border vicinity.  Farther west, a weak low analyzed near
the Black Hills and associated lee trough will aid in maintaining
southerly flow to the south of a residual frontal zone draped over
SD east-northeastward to near Lake Superior. 

Some isolated severe risk may continue this morning with a small
cluster along the Dakotas border primarily to the north of the
front.  Heating of a seasonably moist airmass (60s deg F north and
70s across eastern NE into IA) will contribute to moderate to strong
instability by late afternoon.  Afternoon thunderstorm development
is expected near the surface low and in the vicinity of the surface
boundary/residual outflow across the Dakotas.  Forecast model data
indicates deep-layer shear around 40-45 kts which will support
initial supercells capable of large to very large hail and severe
gusts.  As additional storms develop and cold pools merge and result
in a few clusters evolving with time, the wind threat will likely
increase with stronger gusts associated with bowing segments.  This
activity will likely persist well into the evening with some
lingering severe potentially into the overnight over the MN-IA
vicinity late.

...Southern Appalachians into the Tennessee/Ohio Valleys...
A seasonably moist boundary layer is evident in surface observations
(lower 70s F surface dewpoints) this morning.  Relatively cool
500-mb temperatures around -9 deg C (reference the 12 UTC Nashville,
TN raob) and strong heating will result in fairly steep lapse rates
across this region by early to mid afternoon.  Scattered
thunderstorms are likely and a few stronger clusters will probably
evolve within a weak easterly flow regime to the southwest of an
mid-level anticyclone centered over southwest VA.  The steepened 0-2
km lapse rates and high PW (1.5-1.75 inches) will support wet
microbursts capable of strong to severe gusts (locally 60-70 mph)
with the more intense water-loaded downdrafts.  Modifying the
Nashville raob for forecast afternoon high temperatures in the upper
90s deg F yields extreme MLCAPE (4000+ J/kg).  Due to the magnitude
of buoyancy, have highlighted higher probabilities to account for
increased confidence in a wet microburst threat.  Isolated hail may
also accompany the more intense updrafts.  This activity will
probably coalesce into a few clusters that gradually weaken during
the evening as the wind-damage threat subsides.  

...Central High Plains...
Isolated thunderstorms are expected to develop within the lee trough
across the central High Plains this afternoon.  Moderate instability
overlapping with around 25-30 kts of deep-layer shear will support
potential for a mix of supercells and multicell clusters.  Steep
low- to mid-level lapse rates and large temperature/dew point
spreads will support potential for severe gusts.  Initial supercells
will pose potential for large hail.

...Northeast...  
Northeasterly flow within the northern periphery of the eastern
ridge will allow for thunderstorm activity to track southward out of
Quebec/Ontario across portions of the Northeast this afternoon. 
Uncertainty remains regarding details of convective evolution and
potential corridors of greater threat.  Nonetheless, moderate to
strong instability and 30-40 kt of deep-layer shear will support
storm organization, with damaging gusts being the primary hazard
with the stronger storms.

..Smith/Dean.. 07/02/2026