A Satellite Perspective of the 3 May 1999 Great Plains Tornado Outbreak within Oklahoma

Abstract

Geostationary Operational Environmental Satellite (GOES) imagery from 3 May 1999 is examined. Synoptic-scale water vapor imagery shows a deepening low-amplitude upper-level trough over the western United States on 3 May, which develops a negative tilt as a jet streak digs south-southeastward over California. The imagery also shows a second jet streak propagating rapidly from Baja California to the southern Great Plains. This feature intensifies as it propagates into the diffluent region on the east side of the trough. Thunderstorms initiate as this jet streak moves over western Oklahoma during the late afternoon. GOES visible imagery shows a north?south cloud boundary over southwestern Oklahoma on 3 May. To the west of this boundary, cumulus cloudiness dominates. To the east, stratocumulus and wave (billow) clouds characterize the low-level cloud field. As the jet streak and associated cirrus propagate over northern Texas, towering cumulus clouds develop and then dissipate. As the cirrus clouds propagate over western Oklahoma, towering cumulus clouds develop and persist. This note discusses important features observed in GOES imagery as it pertains to convective morphology. These features were not adequately resolved by the numerical models but were important in the forecast. The benefits of using satellite imagery in combination with model output and other data are discussed.