Severe Thunderstorm Watch 439

Issued

Aug 13, 2021, 6:55 PM MST (01:55 UTC)

Expired

Aug 14, 2021, 3:00 AM MST

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

1 in

Strongest gust expected

60 kt

Counties Cochise County, AZ, Gila County, AZ, La Paz County, AZ, Maricopa County, AZ, Pima County, AZ, Pinal County, AZ, Santa Cruz County, AZ, Yavapai County, AZ, Yuma County, AZ

The Phoenix radar (KIWA), 84 km from the middle of the area, began a volume at 01:56 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Two or more tornadoes

5%

One or more EF2 to EF5 tornadoes

2%

Ten or more severe wind reports

40%

One or more gusts of 65 knots or more

20%

Ten or more severe hail reports

5%

One or more hailstones of 2 inches or more

5%

Six or more combined severe hail and wind reports

60%

• Mesoscale Discussion 1517 Severe potential...watch possibleAug 13, 3:56 PM MST
• Mesoscale Discussion 1521 Severe thunderstorm watch 439Aug 13, 9:24 PM MST
• Mesoscale Discussion 1522 Severe thunderstorm watch 439Aug 14, 12:51 AM MST

613 
WWUS20 KWNS 140152
SEL9  
SPC WW 140152
AZZ000-141000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 439
NWS Storm Prediction Center Norman OK
755 PM MDT Fri Aug 13 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  central and southern Arizona

* Effective this Friday night and Saturday morning from 755 PM
  until 400 AM MDT.

* Primary threats include...
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...An increase in thunderstorm coverage is expected over the
next several hours across parts of central and southern Arizona,
where locally strong/damaging wind gusts will be possible with
stronger storms/convective bands.

The severe thunderstorm watch area is approximately along and 70
statute miles either side of a line from 25 miles east southeast of
Tucson AZ to 65 miles west northwest of Phoenix AZ. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU9).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 437...

AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few
cumulonimbi with maximum tops to 500. Mean storm motion vector
36040.

...Goss

Severe Thunderstorm Watches in Arizona, 2021Every severe thunderstorm watch in 2021

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; radar from the NEXRAD Level II archive.