Copious amounts of tropical moisture streamed northward into far southeastern California on August 24th, ahead of dissipating former tropical storm Ivo. The atmosphere over the lower California deserts became very moist and unstable, and scattered strong thunderstorms developed during the early afternoon hours. The storms generated copious amounts of rain, with rain rates in excess of 3 inches per hour. Flash flooding developed across portions of Imperial and eastern Riverside counties, especially in the area to the west of the Salton Sea. Some of the storms  produced gusty and damaging winds in excess of 60 mph, moderate hail and dense blowing dust. Numerous Flash Flood Warnings, Small Stream Flood Advisories, Severe Thunderstorm Warnings and Significant Weather Advisories were issued mainly during the afternoon hours for the deserts of southeast California.

Dust Storm in IMPERIAL COUNTY EXCEPT THE LOWER COLORADO RIVER VALLEY, CALIFORNIA
From 24-AUG-13 13:55:00 to 24-AUG-13 14:45:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Strong thunderstorms developed across portions of central Imperial county during the  afternoon hours on August 24th, and they generated gusty outflow winds in excess of 50 mph. The winds were sufficiently strong to generate locally dense blowing sand and dust; at 1355PST a trained weather spotter in Seeley reported a dust storm with visibility down to zero miles in dense blowing dust. A Dust Storm Warning was not in effect at the time, however a Severe Thunderstorm Warning was in effect. The Severe Thunderstorm Warning had been issued at 1352PST and continued through 1445PST.

Flash Flood in IMPERIAL, CALIFORNIA
From 24-AUG-13 11:30:00 to 24-AUG-13 17:00:00 (PST-8)
Location: WESTMORELAND
Flood cause: Heavy Rain / Tropical System
Property damage: 100.00K
Crop damage: 0.00K
Reported by: State Official

Copious amounts of tropical moisture from dissipating former tropical storm Ivo spread north into Imperial and eastern Riverside counties on August 24th and this led to a very moist and unstable airmass. Scattered strong thunderstorms with intense rainfall developed across portions of northwest Imperial and south central Riverside counties during the early afternoon hours. Rainfall rates based on radar were in excess of 3 inches per hour at times. The heavy rains led to significant flash flooding to the west of the Salton Sea, affecting areas from Salton City southeastward along highway 86 towards Westmoreland. A Flash Flood Warning was initially issued at 1207PST and it continued in effect until about 1700PST. Radar indicated that some areas west of the Salton Sea and along highway 86 received more than 6 inches of rainfall during the afternoon. According to California state officials, significant flash flooding occurred along highway 86; at 1442PST the California Highway Patrol indicated that Highways 78 and 86 were impassable about 9 miles southeast of Winona. Vehicles were stranded in water near the intersection of Highways 78 and 86. At 1320PST, law enforcement also reported flash flooding in Salton City; cars were stuck in water and the area washes were running heavily. Thunderstorms rains had dissipated by 1700PST and the Flash Flood Warning was replaced by an areal Flood Warning which remained in effect through 2100PST.

Hail in RIVERSIDE, CALIFORNIA
From 24-AUG-13 11:45:00 to 24-AUG-13 12:15:00 (PST-8)
Location: EAGLE MTN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Tropical moisture streaming north into Riverside county led to a very moist and unstable airmass. As a result, very strong thunderstorms developed across central Riverside county during the early afternoon hours on August 24th. Some of the storms affected the community of Eagle Mountain. A COOP observer located in Eagle Mountain reported that large hail, estimated to be one inch in diameter, fell for 30 minutes. No damage was reported due to the large hail.

Flash Flood in RIVERSIDE, CALIFORNIA
From 24-AUG-13 12:30:00 to 24-AUG-13 17:00:00 (PST-8)
Location: DESERT CENTER ARPT
Flood cause: Heavy Rain / Tropical System
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Tropical moisture from dissipating former tropical storm Ivo spread north into eastern Riverside county on August 24th and it led to a very moist and unstable airmass. Strong thunderstorms developed during the early afternoon hours in the area around Desert Center and Eagle Mountain, and they produced copious rainfall with rain rates in excess of 3 inches per hour at times. The first Flash Flood Warning was issued for central Riverside county at 1227PST, and it was re-issued at 1417PST. Eventually the rains dissipated and the warning was allowed to expire at 1715PST. According to local law enforcement, at about 1530PST the heavy rain caused significant flash flooding of Highway 177 near mile marker 5, to the northeast of Desert Center. Numerous vehicles were turning around as the road was impassable.

Thunderstorm Wind in RIVERSIDE, CALIFORNIA
From 24-AUG-13 13:30:00 to 24-AUG-13 14:30:00 (PST-8)
Location: EAGLE MTN
Magnitude: 60.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: COOP Observer

Tropical moisture streamed north into eastern Riverside county on August 24th, and it produced a very moist and unstable airmass. Strong thunderstorms developed during the early afternoon hours and they affected the community of Eagle Mountain. The storms produced gusty and damaging winds, estimated to be at least 60 mph. According to the COOP weather observer in Eagle Mountain, strong thunderstorm winds downed a number of trees and power lines in the area. A Severe Thunderstorm Warning was in effect for the Eagle Mountain area beginning at 1306PST and continuing through 1400PST.

Thunderstorm Wind in IMPERIAL, CALIFORNIA
From 24-AUG-13 13:40:00 to 24-AUG-13 14:40:00 (PST-8)
Location: HOLTVILLE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Tropical moisture from dissipating former tropical storm Ivo spread north into Imperial county on August 24th, and this resulted in a very moist and unstable airmass. Strong thunderstorms developed across portions of central Imperial county during the early afternoon hours, and the storms generated strong gusty winds. According to a trained weather spotter just south of Holtville, a peak wind gust was measured at 60 mph. The strong winds had been gusting for more than one hour in Holtville; they led to the issuance of a Severe Thunderstorm Warning which was issued at 1352PST. The warning remained in effect until 1445PST.