Forecast: Tornadoes possible again today

Posted at 8:31 AM on June 18, 2009 by Paul Huttner

Lightning arcs across the Minneapolis sky last night. Photo by MPR reporter Tom Weber.

Here we go again.

A potent weather system will bring another good chance of severe weather to Minnesota later today. This time, the Twin Cities may be involved.

A combination of weather parameters that favor severe weather are in place today in the southern half of Minnesota. These include:

-A surface warm front and low pressure center moving into southern Minnesota from northern Iowa.
-Abundant moisture with surface dew points in the lower 70s.
-A series of strong upper level waves moving rapidly northeast from Colorado toward Minnesota.
-Strong speed and directional wind shear in the atmosphere to generate and sustain rotating supercell thunderstorms capable of producing large hail, damaging winds and tornadoes.

Both the Twin Cities NWS office and the Storm Prediction Center have highlighted the threats today. SPC has placed southern Minnesota, including the Twin Cities area, under a moderate risk for severe storms today.

The table is set, as we like to say in the weather business. Now it's just a matter of watching when and where the storms will develop today. If there is a wild card today, it may be leftover clouds (convective debris) from this morning's showers and thunderstorms in northern Iowa and southwest Minnesota. Once those clouds move off and if we get enough surface heating to push temperatures into the 80s, new clusters of storms should begin to develop this afternoon, and may push into this evening.

Bottom line? Stay sky aware today, and have a plan should severe thunderstorm or tornado warnings be issued for you area.

Here are some tools to help track the severe weather threat today.

Twin Cities NWS
Sioux Falls NWS
La Crosse NWS
Twin Cities radar loop
Storm Prediction Center

PH

Services

• Hourly Newscast
• HD Radio
• iPhone App / Mobile
• E-mail newsletters
• RSS feeds
• Podcasts
• Submit your photos
• Videos
• Weather
• Most e-mailed stories