Severe Storms in California

The patterns that are associated with the development of severe thunderstorms in California are becoming better understood. Recent research results show that both buoyancy and shear (in certain geographic areas in the state and in certain synoptic patterns) are in the range documented for both non-rotating and supercellular severe storms observed elsewhere in the country. The role of shear in augmenting the buoyancy is a concept that is finding the most difficulty in filtering into the operational environment in places where severe convection is not as frequent as in the central portions of the United States. This notion, that severe thunderstorms in general, and supercells in particular, cannot be supported by the buoyancy typically observed in California, MUST disappear.

California Supercells and Tornadic Thunderstorms

High Sierra Tornado, 7/7/04 Tornado, thunderstorm, hail photos documenting the highest elevation tornado ever observed in the United States. Meteorological analysis is also included. Sunnyvale, CA, F2 Tornado, 5/4/98 Damage photos, Doppler images, vis satellite image and digital images of cloud features for a F2 Damage Producing Tornado, May 4, 1998 Chowchilla Tornadic Mini-Supercell, March 24, 1998 Radar and satellite imagery for a F1 Tornado-producing Supercell in San Joaquin Valley, 3/24/98 Weakly Rotating Thunderstorms Near San Francisco, December 8, 1997 Doppler images, vis satellite image and digital images of cloud features for a Weakly Rotating Thunderstorm,San Francisco, 12/8/97 San Joaquin Valley High-Based Funnels, January 20, 1997 Video images of San Joaquin Valley High-Based Funnels, 1/20/97 Right Moving Tornadic Supercell in San Joaquin Valley, 22 November 1996 Satellite images, animated loop and other images of San Joaquin Valley right-moving Supercell Storm Splitting Supercell with Hook Echo in the San Joaquin Valley, CA(in preparation) Radar signatures, satellite pictures, soundings, surface and upper air charts for a damaging splitting supercell in the San Joaquin Valley Shallow Supercell Tornado Walnut Grove, CA, 23 March 1995 Doppler radar images of a shallow Central Valley supercell producing a Mesocyclone-induced Tornado Day of Shallow Supercell Storms in California, 4 March 1996 Radar and satellite images of California Low-Top Supercell Storms Splitting Storm, 28 February 1996 Doppler images of a California Thunderstorm split F2 Supercell Tornado Near Vina, CA, September 24, 1986 Photos, maps, diagrams for a Sacramento Valley Multiple Vortex Tornado

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Two Tornadoes Near Chico, CA, June 17, 1995

View looking southwest. Tornado on east (left) side of photo was associated with a wall cloud. This storm was one of a line of storms that formed in the Sacramento Valley on the north side of a cutoff low in the mid and upper troposphere. Surface winds were northeasterly and mid-tropospheric winds were easterly. The storms moved southwestward into the San Francisco Bay Region. A sounding and hodograph for this storm eventually will be posted.

Tornadic Wall-cloud, Huntington Beach, January 19, 1993

The tornado maximum in the Orange County area of Southern California is well-documented. In certain synoptic patterns, dynamics and buoyancy (CAPE) combine with topographically- induced favorable wind and wind shear profiles to produce conditions favorable for rotating thunderstorms. I was at Disneyland watching the same wall-cloud phtographed here by Keith Brown. There was a verified F0 tornado at the time.

Information on the southern California tornado maximum can be found in:

Blier, W. and K.A. Batten, 1994: On the incidence of tornadoes in California. WEA. FORECASTING, Vol. 9, 301-315.

Multiple Vortex Mesocyclone-Induced Tornado (F2) Near Chico, CA, September 26, 1986

Photo Courtesy WSO Redding

Braun, S.A. and J.P. Monteverdi, 1991: An investigation of a mesocyclone-induced tornado occurrence in northern California. WEA. FORECASTING, 6, 13-31.

Monteverdi, J.P. and S.A.Braun, 1988: An investigation of the 24 September 1986 "cold sector" tornado outbreak in northern California. National Weather Service Western Region Tech. Mem., NWS-203, 52 pp.

Multiple Vortex Mesocyclone-Induced Tornado (F2) Near Chico, CA, September 26, 1986 Photo Courtesy WSO Redding Braun, S.A. and J.P. Monteverdi, 1991: An investigation of a mesocyclone-induced tornado occurrence in northern California. WEA. FORECASTING, 6, 13-31. Monteverdi, J.P. and S.A.Braun, 1988: An investigation of the 24 September 1986 "cold sector" tornado outbreak in northern California. National Weather Service Western Region Tech. Mem., NWS-203, 52 pp.

Radar Tracing, >60 dbZ Hook Echo, Supercell, Fresno, CA, March 5, 1994 Radar tracing courtesy of Atmospherics, Inc. To see a larger version of this, click here. Information on this storm can be found in: Monteverdi, J.P. and S. Johnson: 1995: A supercell thunderstorm with hook echo in the San Joaquin Valley, California.. WEA. FORECASTING, Vol. 11, 246-261.

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Mesocyclone-Induced Tornado (F1) Near Santa Rosa, CA, December 5, 1992 Photo by Kent Porter Information on this storm will be found in: Monteverdi, J.P. and J. Quadros, 1994: Convective and rotational parameters associated with three tornado episodes in northern and central California. WEA. FORECASTING, 9, 285-300.

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