Alert archive / Arizona / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 35, NWS Flagstaff, AZ

July 31, 2023Coconino County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Jul 31, 2023, 2:33 PM MST for Coconino County, Arizona. It was in force for 27 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, 2:33 PM MST (21:33 UTC)
Expired: Jul 31, 2023, 3:00 PM MST
In force: 27 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 21:36 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, 9.6 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, 5 hours 41 minutes earlier.

Area forecast discussion, Jul 31, 8:52 AM MST, 5 hours 41 minutes before

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In the hours before

Local storm report, Jul 31, 10:56 AM MST, 3 hours 37 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, 3 hours 34 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

Special weather statement, Jul 31, 2:12 PM MST, 21 minutes before

Special Weather Statement
National Weather Service Flagstaff AZ
212 PM MST Mon Jul 31 2023

AZZ012-312145-
Little Colorado River Valley in Coconino County-
212 PM MST Mon Jul 31 2023

...A STRONG THUNDERSTORM WILL IMPACT COCONINO COUNTY THROUGH 245 PM
MST...

At 212 PM MST, Doppler radar was tracking a strong thunderstorm near
Rimmy Jims, or 14 miles northwest of Winslow, moving north at 10 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Rimmy Jims.

This includes the following highways...
 Interstate 40 between mile markers 234 and 245.
 State Route 99 between mile markers 53 and 65.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3504 11084 3503 11101 3524 11106 3518 11082
TIME...MOT...LOC 2112Z 189DEG 8KT 3511 11094

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

BAJ

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, 1:40 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	35 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, 2:52 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.