Severe thunderstorms over eastern Colorado

June 6th, 2012 |
POES AVHRR 12.0 µm IR image + SPC storm reports + METAR surface reports

POES AVHRR 12.0 µm IR image + SPC storm reports + METAR surface reports

Severe thunderstorms developed during the afternoon hours over eastern Colorado on 06 June 2012, which were responsible for a number of tornadoes in addition to widespread large hail and damaging winds (SPC storm reports). An AWIPS image of 1-km resolution POES AVHRR 12.0 µm IR channel data (above) showed a very pronounced “enhanced-V” storm top signature, with many of the severe weather reports located near the vertex of the enhanced-V.

A comparison of 1-km resolution POES AVHRR Cloud Top Temperature (CTT), Cloud Top Height (CTH), and Cloud Type products is shown below. The CTT cold/warm thermal couplet associated with the enhanced-V signature was -74 C/-55 C; the CTH values for the majority of the cirrus canopy were 13 km (12 km within the “warm spot” region of the enhanced-V); and the Cloud Type for the majority of the cirrus canopy was Overshooting (violet color enhancement), with the “Thick Ice” classification (yellow enhancement) within the warm region of the enhanced-V.

POES AVHRR Cloud Top Temperature, Cloud Top Height, and Cloud Type products

POES AVHRR Cloud Top Temperature, Cloud Top Height, and Cloud Type products

A comparison of the 1-km resolution POES 12.0 µm IR image with the corresponding 4-km resolution GOES-15 10.7 µm IR image (below) demonstrated the advantage of improved spatial resolution for detecting the more subtle aspects of the enhanced-V feature. Also note that the enhanced-V feature is displaced to the north and east on the GOES-15 image, due to the problem of parallax associated with the large viewing angle from the GOES-West satellite.

GOES-15 10.7 µm IR + POES AVHRR 12.0 µm IR images

GOES-15 10.7 µm IR + POES AVHRR 12.0 µm IR images

The GOES-15 satellite was placed into Super Rapid Scan Operations (SRSO) mode, providing images as frequently as every 1 minute (see the VISIT Meteorological Interpretation Blog).

One Response to “Severe thunderstorms over eastern Colorado”

  1. Kris Bedka says:

    Our research has shown that the warm spot downwind of the overshooting top is often associated with a stratospheric cirrus plume located at least 0.5 km above the primary anvil. Your AVHRR CTT and CTH graphic highlights one of the pitfalls of computing cloud top height from infrared brightness temperature

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