Updraft: July 21, 2010 Archive

Severe weather numbers impressive

Posted at 8:36 AM on July 21, 2010 by Paul Huttner (1 Comments)
Filed under: Rainfall, Severe weather

Local meteorologists should be getting combat pay this month.

A look at some of the numbers during the onslaught of severe storms the past month by the Twin Cities NWS shows that we've had three times as many reports of severe weather in the past month as we had all of last year!

Here are the numbers from the Twin Cities NWS office:

The June 17th to July 17th Numbers

All statistics are for the 51 county NWS Chanhassen County Warning Area unless otherwise stated.

•395 preliminary reports of severe weather.

•2009 only had 120 total separate severe weather documented and verified.*

•Tornado counts are still being assessed and the surveying, coordinating, and documenting process takes time, thus the initial tornado number count will change some in the coming days to weeks, but to this point 37 have been documented.

•204 total severe thunderstorm and tornado warnings issued, with 72 being tornado warnings.

•The main six events each had at least 20 warnings issued.

•The Storms Prediction Center (SPC) has included some portion of the area in five moderate risks of severe weather in their Day 1 Daily Convective Outlook. The area was under five total moderate risks in the day 1 outlook in the two year span from June 12th, 2008 through June 16th, 2010.

Thundery Thursday:

It appears our next wave of storms will arrive in the early morning hours on Thursday. A strong low level jet stream (around 5k feet) will drive fresh moisture northward from Iowa into southern Minnesota overnight. The moist unstable air will be acted upon by a strong "short wave" in the upper atmosphere, and that should trigger an MCS (Mesoscale convective system) style cluster of organized heavy thunderstorms overnight.

NAM model cranks out 3" to 4" rainfall band for the south metro and southern Minnesota overnight.

The forecast models are cranking out some impressive rainfall totals with this system. Widespread .50" to 1/5" totals appear likely, with the NAM model cranking out an amazing 4" by Thursday afternoon. This is probably high for most areas....but it gives you the idea that there may be some locally heavy and potentially flooding rains with this system.

(Click for bigger image)

Keep an eye and ear out for heavy rainfall and severe weather again early Thursday.

PH

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