National Weather Service United States Department of Commerce

Storm Moving through the South; Pacific Storm to Impact the West this Weekend

A storm is expected to develop over the southern High Plains today and track to the Mid-Atlantic through Friday with showers and thunderstorms. On the northern edge, snow, ice, and/or a wintry mix is possible over the central Plains. A significant storm is expected to arrive late Friday through the weekend with rain, heavy mountain snow, and gusty winds for much of the West. Read More >

Severe storms wrack the area on July 26 2008

 

Isolated severe thunderstorms developed Thursday night over sections of the forecast area. The thunderstorms produced strong winds up to 70 mph, large hail, and heavy rainfall. The strongest storm developed over Branch county Michigan Thursday evening. Ample instability along with moderate wind shear (change in wind speed and direction with height) allowed the updraft of this thunderstorm to become intense. Strong rotation developed in this storm in response to the wind shear present, allowing the development of what is known as a supercell thunderstorm. This supercell thunderstorm dropped hail up to the size of golf balls along with wind gusts to 70 mph as it moved southeast into northeast Indiana and northwest Ohio. A funnel cloud was also observed with this storm just west of Edon Ohio at 843 pm EDT. Below are a few radar images taken from when the thunderstorm updraft was very intense. At this time the storm was producing golf ball size hail over Williams and Defiance counties.

5.1 degree reflectivity image
Very intense radar returns are evident in the above image. The large hail produced an intense return of 70 dbz at approximately 24,000 ft above the ground. Meteorologists correlate reflectivity to temperature levels aloft in determining hail potential.

 
7.9 degree reflectivity images
The above image displays radar reflectivity at about 35,000 ft above ground level. This image was taken about same time as the image above. Again, very “hard” returns of 60 dbz can be seen emanating from near the top of the thunderstorm right near the middle of the hail growth zone.

 

The following sequence of pictures shows the collapse of the hail core in western Defiance county. Also, evident on the left hand side of the first image is the echo free vault of the thunderstorm. An echo free vault is an attribute of a very intense thunderstorm as it indicates that the updraft is strong enough to suspend precipitation particles (such as hail) aloft for a long period of time.

 

A 3D rendering of this storm, at 840 pm EDT over Edon Ohio, below clearly shows the deep ice core within this intense supercell. Spiral indicates the intense mesocyclone occurring within the updraft and caught on video by storm chaser Steve Ferree. Note the brief funnel that develops below the base of this intense mesocyclone.

 

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