Heavy rainfall and flooding in Las Vegas, Nevada

September 11th, 2012 |
POES AVHRR 0.86 µm visible channel + 12.0 µm IR channel images at 20:23 UTC

POES AVHRR 0.86 µm visible channel + 12.0 µm IR channel images at 20:23 UTC

A daily record of 1.18 inches of rainfall was recorded at McCarran International Airport in Las Vegas, Nevada on 11 September 2012 — this was also the highest daily rainfall total on record for any day in the month of September. Some locations in the Las Vegas metro area received as much as 2.09 inches (Public Information Statement), with 3.35 inches falling in the higher elevations (7450 feet) to the west of the city at Mt. Charleston. AWIPS images of 1-km resolution POES AVHRR 0.86 µm visible channel and 12.0 µm IR channel images at 20:32 UTC (above) and 21:26 UTC (below) showed evidence of overshooting tops and cloud top IR brightness temperatues as cold as -65º C (darker red color enhanement).

POES AVHRR 0.86 µm visible channel + 12.0 µm IR channel images at 21:26 UTC

POES AVHRR 0.86 µm visible channel + 12.0 µm IR channel images at 21:26 UTC

10-km resolution GOES Sounder Total Precipitable Water (TPW) derived product images (below) showed the TPW values were as high as 45 mm (1.78 inches) across parts of Clark County in southern Nevada during the hours leading up to the development of the thunderstorms.

GOES Sounder Total Precipitavble Water derived product imagery

GOES Sounder Total Precipitavble Water derived product imagery

The Blended Total Precipitable Water (TPW) Percent of Normal product (below) indicated that TPW values across the region were in excess of 200% of normal (yellow color enhancement).

Blended Total Precipitable Water Percent of Normal product

Blended Total Precipitable Water Percent of Normal product

With afternoon heating, GOES Sounder Convective Available Potential Energy (CAPE) values (below) exceeded 2600 J kg-1 (darker yellow color enhancement) in the pre-convective environment.

GOES Sounder Convective Available Potential Energy (CAPE) product

GOES Sounder Convective Available Potential Energy (CAPE) product

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