Updraft: June 22, 2010 Archive

Quiet now - becoming volatile

Posted at 10:39 AM on June 22, 2010 by Craig Edwards (2 Comments)
Filed under: Severe weather

Visible satellite image from mid morning.

Checking the latest weather parameters it appears that this extensive sunshine will broil over into a very unstable airmass this afternoon. Strong thunderstorms with damaging winds, large hail and possibility of tornadoes will become more likely from mid afternoon into the evening.

The best chance for severe weather will be from about Montevideo to Hutchinson to Northfield and points south. However, the Twin Cities is in the threat area.

Keep your hear to the radio and an eye to the sky as the afternoon progesses. I'm starting to feel something bad in the air.

here's your go to page to get a heads up from the National Weather Service in Chanhassen.

Updates throughout the day and on ATC this afternoon.
CE

Watching and waiting

Posted at 2:11 PM on June 22, 2010 by Craig Edwards
Filed under: Severe weather

The atmosphere continues to heat up this afternoon with high low level moisture in place. What we are looking for at this time is the trigger to ignite thunderstorms later today.

Conditions that will come into play are the unstable air, low level shear of the winds (turning from southeast to west as you ascend the atmosphere), a ripple of a middle level pressure trough, and an upper level wind maximum.

Here is the wording on the latest thinking from the Storm Prediction Center as of noon:

THE SEVERE STORMS LIKELY WILL ORGANIZE INTO SEVERAL LARGE CLUSTERS
LATER THIS EVENING AND EARLY WEDNESDAY...MOST LIKELY OVER SOUTHERN AND EASTERN SOUTH DAKOTA AND WESTERN AND NORTHERN NEBRASKA.

ONE OR TWO OF THESE CLUSTERS COULD BECOME LONG-LASTING...WITH THE POTENTIAL TO PRODUCE MORE WIDESPREAD DAMAGING WINDS AND HAIL...AS THEY MOVE GENERALLY EAST INTO PARTS OF IOWA...SOUTHERN MINNESOTA...ILLINOIS AND SOUTHWESTERN WISCONSIN THROUGH DAWN WEDNESDAY.
CE

Moderate risk remains

Posted at 2:55 PM on June 22, 2010 by Craig Edwards
Filed under: Severe weather

Tornado probability as defined by the Storm Prediction Center for this evening and overnight is around ten percent. There is a higher probability of straightline damaging winds and large hail, in the range of 40 to 45 percent.

Safety tips for tornadoes:
Monitor two sources for information, including NOAA Weather Radio.
Plan on where you will locate if a warning is issued. Lowest floor away from windows and under furniture if possible to protect against falling or flying debris.
In an appartment, the stairwell on the lowest floor is one of the best shelters.
If you can't make it from your appartment try to get under the bed or a behind a piece of heavy furniture. The bathroom or and interior closest also offers some protection.
Place a flashlight where you can easily access it if the power goes out.
Have access to a working portable radio.
Phone someone to inform them if you believe they are disconnected from a source of weather information.

Satellite mid afternoon

Posted at 3:25 PM on June 22, 2010 by Craig Edwards
Filed under: Severe weather

Visible satellite image from mid afternoon.

Note the line of showers and thunderstorms developing in the vicinity of Alexandria, Minnesota. Keeping an eye out for further development and changes in intensity during the heat of the day.
CE

Looking for the trigger

Posted at 7:02 PM on June 22, 2010 by Craig Edwards
Filed under: Severe weather

Water vapor satellite image from 645pm CDT. The brighter the colors, including the blue mean colder/higher cloud tops.

After heating up to the first ninety degree day in the Twin Cities since May 29th we have plenty of fuel for Mother Nature to ingnite tonight.

Examining the late afternoon water vapor satellite image it appears that the missing piece of the severe weather puzzle is showing up in western Nebraska.

Thunderstorms are more likely to fire up after dark and spawn locally heavy rain for parts of southern Minnesota. The risk of severe weather also remains.
CE