Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1219 PM CDT Mon Jun 29 2026

Valid 301200Z - 011200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
WISCONSIN AND THE UPPER PENINSULA OF MICHIGAN...PARTS OF NEW YORK
AND VERMONT...AND THE CENTRAL PLAINS...

...SUMMARY...
Severe thunderstorms will be possible from parts of the central High
Plains into the Upper Midwest, and across parts of the Northeast on
Tuesday.

...Northeast...

Enhanced northwesterly flow aloft on the northeastern periphery of
an amplified upper ridge will overspread the region on Tuesday. This
area will also be on the southerly periphery of a strengthening
southwesterly low-level jet oriented across Ontario/Quebec. This
will support effective shear magnitudes around 40+ kt. Supercell
structures will be possible, but most guidance suggests convection
will develop into one or more forward propagating clusters/bowing
segments. Damaging wind gusts will be the main hazard with this
activity as it moves across a very moist and moderately unstable
airmass. Given supercell wind profiles and enlarged, favorably
curved hodographs, a couple of tornadoes also will be possible,
especially if a more semi-discrete storm mode occurs. While details
in convective evolution vary some among various guidance, a
consistent signal exists (particularly across northern NY into VT)
and a Slight risk (Level 2 of 5) has been included. Convection
should gradually decrease in intensity with southeast extent toward
southern New England and the Mid-Atlantic vicinity as instability
decreases and inhibition increases. 

...Upper Midwest/Great Lakes...

An upper low and attendant shortwave trough initially over the
Canadian Prairies and northern MN will gradually shift
east/northeast through the period. Height tendencies will generally
be neutral across the area given the strong upper ridge just to the
east. Enhanced southwesterly deep-layer flow will persist across the
region, with some intensification of a low-level jet by late
afternoon/evening. At the surface, a quasi-stationary boundary is
forecast to extend from near the MN Arrowhead, southward into
eastern NE at midday. To the south/east of the boundary, a very
moist airmass with 70s dewpoints is forecast. A corridor of strong
to extreme instability is depicted by some model guidance across
northern WI into the U.P. of Michigan. Convection may develop near
the surface boundary and shift east across northern portions of the
Great Lakes. If this occurs, damaging winds (some near 80 mph) could
accompany thunderstorm clusters potentially organizing into a bowing
MCS.

Some guidance develops additional convection overnight across parts
of southern MN/WI into northern IA and vicinity. This activity would
be supported by a warm front lifting northward across the central
Plains and Mid-MO Valley and an intensifying southwesterly low-level
jet. While ample instability will exist across the area, it is
uncertain if this activity would be surfaced-based. Nevertheless, a
favorable thermodynamic and kinematic environment would support some
severe wind/hail risk.

...Southern/Central High Plains...

Modest height falls are forecast as a midlevel shortwave impulse
ejected across the central Rockies into NE/SD from late afternoon
into the overnight hours. A surface trough/dryline will sharpen as a
result, and southerly low-level flow will transport low 60s
dewpoints northward along the boundary beneath steep midlevel lapse
rates. High-based convection is expected to develop by late
afternoon and shift east/northeast through evening. Initial
supercells could produce large to very large hail. With time, some
upscale development could occur via consolidating outflows and as
the low-level jet increases during the evening. This could bring an
increasing risk for damaging winds, a few possibly approaching 80
mph. Given a consistent signal across various CAMs, deterministic
and ML/AI guidance, a Slight risk (level 2 of 5) has been added.

...LA/MS/AL/GA/FL Panhandle...

Forecast guidance depicts 25-35 kt midlevel northeasterly flow on
the southern periphery of an upper high centered over the OH/TN
Valley. A very moist airmass will be present across much of the
region and strong destabilization is forecast amid strong daytime
heating. Forecast soundings depict around 20-30 kt effective shear
magnitudes, supporting some risk of organized cells/clusters.
Isolated damaging wind gusts are possible as activity develops
west/southwest through early evening.

..Leitman.. 06/29/2026