Alert archive / Arizona / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 33, NWS Flagstaff, AZ

July 31, 2023Coconino County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Jul 31, 2023, 1:40 PM MST for Coconino County, Arizona. It was in force for 35 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: Jul 31, 2023, 1:40 PM MST (20:40 UTC)
Expired: Jul 31, 2023, 2:15 PM MST
In force: 35 min
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Coconino County, AZ

The radar

The Flagstaff radar (KFSX), 150 km from the middle of the area, began a volume at 20:42 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

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 8.7 hours before the alert went out and 68 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: 7 J/kg
Mixed-layer CIN: -180 J/kg
Mixed-layer LCL: 1455 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 101 m²/s²
0-3 km storm-relative helicity: 91 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 Jul 31, 8:52 AM MST, 4 hours 48 minutes earlier.

Area forecast discussion, Jul 31, 8:52 AM MST, 4 hours 48 minutes before

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In the hours before

Local storm report, Jul 31, 10:56 AM MST, 2 hours 44 minutes before

Preliminary Local Storm Report
National Weather Service Flagstaff AZ
1056 AM MST Mon Jul 31 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0310 PM     Tstm Wnd Gst     Ash Fork                35.22N 112.48W
07/30/2023  E60 MPH          Yavapai            AZ   Trained Spotter

            Estimated 60 mph winds, along with
            frequently lightning and heavy rainfall.

&&

RJR

Local storm report, Jul 31, 10:59 AM MST, 2 hours 41 minutes before

Preliminary Local Storm Report
National Weather Service Flagstaff AZ
1059 AM MST Mon Jul 31 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0600 PM     Flash Flood      Ash Fork                35.22N 112.48W
07/30/2023                   Yavapai            AZ   Trained Spotter

            Roads in the area were impassable.

&&

RJR

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 30, 7:07 PM MST	Areal Flood Advisory	FGZ	Coconino, Navajo	2 hr
Jul 31, 12:15 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	30 min
Jul 31, 12:20 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	25 min
Jul 31, 12:34 PM MST	Severe Thunderstorm Warning	FGZ	Apache, Navajo	26 min
Jul 31, 12:55 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	35 min
Jul 31, 1:07 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	23 min
Jul 31, 1:19 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	26 min
Jul 31, 1:48 PM MST	Severe Thunderstorm Warning	FGZ	Coconino, Navajo	27 min
Jul 31, 2:12 PM MST	Special Weather Statement	FGZ		33 min
Jul 31, 2:33 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	27 min
Jul 31, 2:52 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	12 min
Jul 31, 4:00 PM MST	Areal Flood Advisory	FGZ	Coconino, Yavapai	3 hr
Jul 31, 4:33 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr

Nearby

Severe Thunderstorm Warnings in Arizona, 2023 Every severe thunderstorm warning in 2023

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.