Alert archive / Arizona / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 16, NWS Flagstaff, AZ

August 16, 2020Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Aug 16, 2020, 4:55 PM MST for Yavapai County, Arizona. It was in force for 34 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 16, 2020, 4:55 PM MST (23:55 UTC)
Expired: Aug 16, 2020, 5:29 PM MST
In force: 34 min
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 124 km from the middle of the area, began a volume at 23:58 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.

The nearest sounding before it

Phoenix, AZ (KPSR), launched 12:00Z, 11.9 hours before the alert went out and 141 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: 267 J/kg
Mixed-layer CIN: -579 J/kg
Mixed-layer LCL: 2754 m above ground
0-6 km bulk shear: 3 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: 8 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Flagstaff, AZ wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 16, 2:31 PM MST, 2 hours 24 minutes earlier.

Area forecast discussion, Aug 16, 2:31 PM MST, 2 hours 24 minutes before

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In the hours before

Special weather statement, Aug 16, 1:14 PM MST, 3 hours 41 minutes before

Special Weather Statement
National Weather Service Flagstaff AZ
114 PM MST Sun Aug 16 2020

AZZ017-162045-
White Mountains-
114 PM MST Sun Aug 16 2020

...SIGNIFICANT WEATHER ADVISORY SOUTH OF WHITERIVER UNTIL 145 PM
MST...

At 113 PM MST, Doppler radar was tracking a strong thunderstorm 8
miles south of Seven Mile, or 39 miles south of Show Low, moving
south at 15 mph.

Nickel size hail and winds in excess of 40 mph will be possible with
this storm.

This storm will remain over mainly rural areas of Navajo County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3357 10996 3358 10996 3358 11000 3373 11000
      3375 10991 3358 10990 3358 10992 3357 10993
TIME...MOT...LOC 2013Z 345DEG 14KT 3366 10996

TPS

Special weather statement, Aug 16, 2:27 PM MST, 2 hours 28 minutes before

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Local storm report, Aug 16, 2:35 PM MST, 2 hours 20 minutes before

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Special weather statement, Aug 16, 2:57 PM MST, 1 hour 58 minutes before

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Special weather statement, Aug 16, 3:48 PM MST, 1 hour 7 minutes before

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Special weather statement, Aug 16, 3:54 PM MST, 1 hour 1 minute before

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The office that day

Everything else NWS Flagstaff, AZ issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 16, 1:14 PM MST	Special Weather Statement	FGZ		31 min
Aug 16, 2:27 PM MST	Special Weather Statement	FGZ	Yavapai	33 min
Aug 16, 2:57 PM MST	Special Weather Statement	FGZ	Yavapai	33 min
Aug 16, 3:15 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	27 min
Aug 16, 3:48 PM MST	Special Weather Statement	FGZ	Yavapai	42 min
Aug 16, 3:54 PM MST	Special Weather Statement	FGZ		51 min
Aug 16, 4:09 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	30 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2020 Every severe thunderstorm warning in 2020

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; radar from the NEXRAD Level II archive.