Alert archive / Arizona / Tornado Watches in 2010

Tornado Watch 8

January 21, 20105 counties in Arizona

The Storm Prediction Center issued this tornado watch at Jan 21, 2010, 4:12 PM MST for 5 counties in Arizona. It was in force for 9 hr.

The area

The outline as issued.

The facts

Issued: Jan 21, 2010, 4:12 PM MST (23:12 UTC)
Expired: Jan 22, 2010, 1:00 AM MST
In force: 9 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 70 kt

Counties La Paz County, AZ, Maricopa County, AZ, Pima County, AZ, Pinal County, AZ, Yuma County, AZ

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 30%
One or more EF2 to EF5 tornadoes: 5%
Ten or more severe wind reports: 50%
One or more gusts of 65 knots or more: 40%
Ten or more severe hail reports: 20%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

16 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jan 21, 4:14 PM MST	Tornado Warning	PSR	La Paz	46 min
Jan 21, 4:31 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Yuma	59 min
Jan 21, 4:47 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Yuma	45 min
Jan 21, 5:30 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Yuma	17 min
Jan 21, 6:22 PM MST	Severe Thunderstorm Warning	PSR	Yuma	53 min
Jan 21, 6:26 PM MST	Flash Flood Warning	PSR	Yuma	5 hr
Jan 21, 7:27 PM MST	Severe Thunderstorm Warning	TWC	Pima	63 min
Jan 21, 7:38 PM MST	Flash Flood Warning	PSR	Gila, Maricopa, Pinal	112 min
Jan 21, 8:31 PM MST	Severe Thunderstorm Warning	TWC	Pima, Pinal	59 min
Jan 21, 8:32 PM MST	Tornado Warning	PSR	Maricopa	28 min
Jan 21, 8:45 PM MST	Tornado Warning	PSR	Maricopa	15 min
Jan 21, 9:03 PM MST	Tornado Warning	PSR	Maricopa, Pinal	13 min
Jan 21, 9:30 PM MST	Flash Flood Warning	PSR	Gila, Maricopa, Pinal	5 hr
Jan 21, 9:30 PM MST	Severe Thunderstorm Warning	TWC	Pima, Pinal	60 min
Jan 21, 10:33 PM MST	Severe Thunderstorm Warning	TWC	Pima, Pinal	57 min
Jan 21, 11:26 PM MST	Severe Thunderstorm Warning	TWC	Pima, Pinal	49 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Yuma Intl Airpor, AZ (KYUM), launched 12:00Z, 11.2 hours before the alert went out and 136 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 12 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 590 m above ground
0-6 km bulk shear: 69 kt
0-1 km storm-relative helicity: 269 m²/s²
0-3 km storm-relative helicity: 342 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 21, 3:34 PM MST	Mesoscale Discussion	SPC	La Paz, Yuma	56 min

Nearby

Tornado Watches in Arizona, 2010 Every tornado watch in 2010

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.