RSS Mesoscale Discussions from Storm Prediction Center
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0735 AM CDT Wed Jul 01 2026
Valid 011300Z - 021200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE MIDWEST INTO THE UPPER GREAT LAKES...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL HIGH PLAINS AND THE NORTHEAST...
...SUMMARY...
Scattered severe thunderstorms are forecast across the Upper
Midwest/Great Lakes today and tonight. A couple of tornadoes are
possible but damaging wind gusts are expected to be the more
widespread hazard, in addition to isolated large to very large hail.
Additional severe storms are possible across parts of the central
High Plains and Northeast.
...Midwest and Upper Great Lakes ...
Showers and thunderstorms this morning are moving east over the
Upper Midwest and are associated with a couple of MCVs over
northwest IA and the SD-MN border. The ongoing strong to locally
severe thunderstorm activity is situated in the vicinity of a
west-east oriented frontal zone draped from MN east across WI and
into the U.P. of MI. (see MCD #1413 for short-term details). The
airmass south of the boundary is very moist with lower to mid 70s F
surface dewpoints.
The Sioux Falls, SD (KFSD), Minneapolis, MN (KMPX), and the La
Crosse, WI (KARX) VAD this morning are sampling a belt of strong
southwesterly mid- to high-level flow (50+ kt in the 5-9km ARL
layer). KARX has recently sensed an intensification of flow in the
3-6 km layer, which may influence the threat for wind damage/large
hail beyond an isolated basis and beginning as early as late
morning. Furthermore, it seems the strengthening of flow as
depicted in some model guidance (upwards of 40-45 kt at 700 mb) may
be of consequence for organizing multicells but also supercells
during the day. The details concerning the tornado risk remain
unclear and will likely remain mesoscale dependent and related to
the persistence of morning convection and the airmass recovery, but
it seems plausible the threat for supercell tornadoes would perhaps
focus over WI and possibly extend into southern MN/northern IA this
afternoon in wake of this morning's WAA-driven activity. Large to
very large hail will be possible with the more intense storms in
addition to wind, which may become more prevalent of a hazard (60-75
mph) as storm mergers lead to a couple of strong to severe clusters
developing.
...Central and southern High Plains...
High-based thunderstorm development is expected along a
north/south-oriented lee trough/dryline during the afternoon and
evening. Despite modest deep-layer shear (around 25-30 kt), steep
low/mid-level lapse rates will contribute to a strongly unstable
airmass. A mix of loosely organized clusters and possibly some
supercell structures will be capable of producing severe wind gusts
and large hail. Farther south, weaker flow will limit overall storm
organization, but steep lapse rates will support severe gusts with
the more intense downdrafts.
...Northeast...
Enhanced west-northwesterly midlevel flow will persist across the
Northeast, where a warm/moist air mass will contribute to around
3000 J/kg MLCAPE. While nebulous mesoscale forcing for ascent casts
uncertainty on overall convective coverage and evolution, the strong
buoyancy and a veering wind profile (albeit modest deep-layer shear)
will favor east-southeastward-spreading convection capable of
damaging wind gusts and isolated hail during the afternoon and again
during the evening/nighttime hours.
...Southeast...
Along the southern periphery of a midlevel anticyclone centered over
the central Appalachians, weak easterly flow through much of the
troposphere will overspread a hot/moist air mass with 3000-4000 J/kg
MLCAPE during the afternoon. Strong to severe pulse thunderstorms
are forecast. The stronger water-loaded wet microbursts will yield
localized gusts of 50-65 mph and be capable of wind damage.
...MT into the northern Great Basin...
Isolated to widely scattered thunderstorms are expected ahead of a
slow-moving midlevel trough moving across the Northwest. Preceding
the trough, around 40 kt of midlevel southwesterly flow and a weakly
unstable air mass will support a couple loosely organized clusters
capable of producing severe wind gusts during the afternoon and
evening. Have extended low-severe probabilities farther south into
ID/NV/UT where inverted-V profiles will support isolated severe
gusts.
..Smith/Dean.. 07/01/2026
Read more
