Severe T-Storm Watch until 8 pm for southeast Minnesota and Wisconsin

NOAA's Storm Prediction Center has issued a severe thunderstorm watch until 8 pm for much of western Wisconsin. The watch zone includes the Wisconsin counties in the eastern Twin Cities, and much of southeast corner of Minnesota including Rochester.

URGENT - IMMEDIATE BROADCAST REQUESTED

Severe Thunderstorm Watch Number 120

NWS Storm Prediction Center Norman OK

200 PM CDT Fri May 25 2018

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of

Northeast Iowa

Southeast Minnesota

Western and Central Wisconsin

* Effective this Friday afternoon and evening from 200 PM until

800 PM CDT.

* Primary threats include...

Scattered large hail and isolated very large hail events to 2

inches in diameter possible

Scattered damaging wind gusts to 70 mph possible

SUMMARY...Scattered intense thunderstorms are expected to form this

afternoon in a moist and unstable air mass. The strongest cells

will be capable of large hail and damaging wind gusts.

Landspout

Storms today produced a brief "landspout" type tornado in southern Minnesota. Under today's weather parameters these brief spin-ups are short-lived.

Here's a definition of a landspout tornado from NOAA.

 A landspout is a tornado with a narrow, rope-like condensation funnel that forms while the thunderstorm cloud is still growing and there is no rotating updraft - the spinning motion originates near the ground.

A tornado that does not arise from organized storm-scale rotation and therefore is not associated with a wall cloud (visually) or a mesocyclone (on radar). Landspouts typically are observed beneath Cbs or towering cumulus clouds (often as no more than a dust whirl), and essentially are the land-based equivalents of waterspouts.

Unlike most tornadoes which form beneath a rotating (supercell) thunderstorm, landspout tornadoes form when an area of preexisting rotation near the ground becomes positioned beneath a rapidly developing thunderstorm cloud. The quickly rising air lifting into the cloud stretches the area of rotation near ground level vertically, resulting in an intensification of the spin and the formation of a landspout tornado. Normally landspout tornadoes don't last very long or get very strong, though they can do minor damage before dissipating.