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Heavy precipitation for parts of the Pacific Northwest

Moisture will continue to stream into the Pacific Northwest for the next several days. Heavy rain will continue along the coast, while heavy snow will impact the highest elevations of the Cascades. In the northern Plains and Upper Great Lakes, more arctic air will bring periods of snow, blustery winds and cold wind chills. Light snow is also possible in New England and the Ohio Valley. Read More >

Photo of wet downburst in Norman, OK on June 14, 2011
Photo provided courtesy of Justin Linck.
Taken at I-35 and Main St in Norman looking NW.
Radar reflectivity loop of the severe thunderstorm as it it moved through Norman, OK.
To See a Radar Animation, Click the Above Image.
 
 

Overview

 

Thunderstorms quickly developed along a slow-moving cold front that was located near I-44 by late afternoon. Several locations reported wind gusts well over 60 mph, with the highest measured gust of 82 mph! Large hail to baseball size was also reported. Many communities reported damage as a result of the high winds, large hail, or a combination of both.

 

Synopsis

 

From approximately 7:20 pm to 7:45 pm, a wet downburst affected areas in and around Norman and southeast Oklahoma City, Oklahoma. Intense rainfall was accompanied by hail up to golf-ball size and winds that were measured at over 80 mph. Damage was reported over much of the city, with the most intense damage occurring over the northern half of the city. Almost 33,000 residents were without power, some still without power over 24 hours later. This was due to the numerous power poles/lines that were snapped or blown down. In addition to the high wind, hail up to golf ball size fell almost horizontally, damaging siding, shattering store signs, and denting automobiles. The highest measured wind gust occurred near SE 12th and Boyd, where the anemometer recorded 82 mph before it malfunctioned due to the wind blown hail. The Norman mesonet site also measured a gust of 70 mph. A quick inch of rain occurred in about 15 to 20 minutes, which resulted in some minor flash flooding. Here are a few facts about yesterdays severe weather event:

  • The damage that occurred in and around Norman, OK was caused by a downburst, not a tornado. The turbulent cloud motions along the leading edge of the "rain foot" can sometimes give the appearance of a descending funnel. Downburst winds have been known to produce wind speeds in excess of 100 mph.
  • The highest measured wind speed occurred over the northern and central portions of Norman, where an anemometer measured 82 mph.
  • The largest reported hail side was 2.75" (baseball-size), which fell one mile south of Cushing, Oklahoma. Golfball size hail (1.75") was also reported in Norman along with the damaging winds.
 

What Is A Downburst?

 

Downbursts occur when precipitation in a thunderstorm drags air downward to the ground at high speeds, and it then spreads out along the ground. For more information, see this page from the NWS JetStream Online Weather School.

Schematic of a Microburst from a Severe Thunderstorm

 

Storm Photos

 
June 14, 2011 Wind Damage in Norman, OK
Photo taken near 12th Street and Robinson -
Griffin Park (David Grizzle)
June 14, 2011 Wind Damage in Norman, OK
Photo taken near 12th Street and Robinson -
Griffin Park (David Grizzle)
June 14, 2011 Wind Damage in Norman, OK
Photo taken at Max Westheimer Airport -
(Robin Tanamachi)
June 14, 2011 Wind Damage in Norman, OK
Photo taken at Max Westheimer Airport -
(Robin Tanamachi)
June 14, 2011 Wind Damage in Norman, OK
Wind Damage at Max Westheimer Airport -
(Robin Tanamachi)
June 14, 2011 Wind Damage in Norman, OK
Wind Damage at Max Westheimer Airport -
(Robin Tanamachi)
 

Storm Videos

 

Video provided courtesy of Jim Ladue

Video provided courtesy of Ashton Robinson Cook

Video provided courtesy of Robin Tanamachi