Updraft: June 18, 2009 Archive

Forecast: Tornadoes possible again today

Posted at 8:31 AM on June 18, 2009 by Paul Huttner (0 Comments)

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

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Storms increasing now, watches ahead

Posted at 1:09 PM on June 18, 2009 by Paul Huttner (0 Comments)

SPC mesoscale discussion highlights west central Minnesota for a possible severe weather watch.

Storms are firing near Alexandria early this afternoon. Doppler indicates the presence of large hail as big as 2 inches in diameter with this storm.

SPC is monitoring the area and may issue a watch soon for the area.

So far all is quiet in southern Minnesota, but the sun is causing rapid heating and destabilization of the atmosphere and storms may begin to develop soon.

PH

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Storm reports

Posted at 2:23 PM on June 18, 2009 by Paul Huttner (0 Comments)

I'll add significant storm reports here.

PH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
159 PM CDT THU JUN 18 2009

0140 PM HAIL 5 W URBANK 46.13N 95.61W
06/18/2009 E2.50 INCH OTTER TAIL MN PUBLIC
LOTS OF GOLF BALL AND LARGER HAIL...SIGNIFICANT TREE
DAMAGE

MPX: Alexandria [Douglas Co, MN] law enforcement reports FUNNEL CLOUD at 02:34 PM CDT -- 2 funnels down and up in cloud did not touch ground also witnessed by ham radio operator.

MPX: Alexandria [Douglas Co, MN] trained spotter reports HAIL of golf ball size (E1.75 INCH) at 02:32 PM CDT --

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Austin tornado video

Posted at 4:06 PM on June 18, 2009 by Paul Huttner (0 Comments)

Pretty amazing video from storm chasers last night in Austin.
NWS survey teams rated the torndo an EF2.

PH

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