NWS: 1" severe hail criteria goes nationwide

Posted at 4:34 PM on November 18, 2009 by Paul Huttner

Last night's Twin Cities AMS Chapter meeting featured Dr. Joe Schaefer, Director of the Storm Prediction Center (SPC). While I was unable to attend last night, my weather spies tell me he broke some news at the meeting.

You may remember last summer the NWS Central Region which includes Minnesota changed the criteria for severe hail to 1" from the previous 3/4" threshold for issuing severe thunderstorm warnings based on hail size. This move was supported by me and many other local meteorologists. It appears the change was a success. Next year, the NWS will adopt the 1" standard nationwide.

It turns out you need hail closer to 2" in diameter (golf ball size) before you really start to do serious structural damage to windows and cars. Since hailstones that size fall at nearly 100 mph, it's probably wise to stick with the 1" criteria when it comes to people outdoors. I wouldn't want to be caught out on the lake in 1" hail. This is a good move by NWS.

I'm told Joe also said SPC is very concerned and will be watchful this winter for tornado outbreaks along the Gulf Coast and in Florida. El Nino winters have a history of producing deadly winter time tornado outbreaks in the Deep South.

SPC is also talking about how to increase the alert level for killer tornadoes that occur during the overnight hours.

Delta moves NWA meteorologists to Atlanta:

Another little bird told me that Delta Airlines is completing the move of the former NWA meteorology staff to Atlanta. When complete, this marks the first time the "hometown airline" has not had a staff of trained meteorologists based in the Twin Cities in decades.

In theory this should not have an effect on the quality of weather forecasts for airline operations at MSP. However, I for one have always been a big believer in the extra "eyes on the ground" data you get from having a locally based staff of weather professionals based at MSP Airport. After all, this is one of the most challenging locations for flight operations in the world, especially in winter.

I am digging deeper into this topic.

Stay tuned.

PH

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