Alert archive / Arizona / Special Weather Statements in 2021

Special Weather Statement, NWS Phoenix, AZ

September 18, 2021Pinal County, Arizona

NWS Phoenix, AZ issued this special weather statement at Sep 18, 2021, 4:34 PM MST for Pinal County, Arizona. It was in force for 41 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Sep 18, 2021, 4:34 PM MST (23:34 UTC)
Expired: Sep 18, 2021, 5:15 PM MST
In force: 41 min
Issued by: NWS Phoenix, AZ
Hail: 0.00 in
Wind: 40

County Pinal County, AZ

The radar

The Phoenix radar (KIWA), 38 km from the middle of the area, began a volume at 23:33 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, 11.6 hours before the alert went out and 52 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: 240 J/kg
Mixed-layer CIN: -237 J/kg
Mixed-layer LCL: 2129 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 7 m²/s²
0-3 km storm-relative helicity: 94 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

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

NWS Phoenix, AZ wrote its last area forecast discussion before this special weather statement went out at Sep 18, 4:10 PM MST, 24 minutes earlier.

Area forecast discussion, Sep 18, 4:10 PM MST, 24 minutes before

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In the hours before

Special weather statement, Sep 18, 2:46 PM MST, 1 hour 48 minutes before

Special Weather Statement
National Weather Service Phoenix AZ
246 PM MST Sat Sep 18 2021

AZZ553-554-559-182230-
Sonoran Desert Natl Monument AZ-Northwest Pinal County AZ-
West Pinal County AZ-
246 PM MST Sat Sep 18 2021

...A strong thunderstorm will impact portions of Maricopa and Pinal
Counties through 330 PM MST...

At 245 PM MST, Doppler radar was tracking a strong thunderstorm near
Maricopa, or 21 miles southwest of Sun Lakes, moving northeast at 25
mph.

HAZARD...Winds in excess of 40 mph, pea size hail, and blowing dust.

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...
Casa Grande, Maricopa, Estrella Sailport, Olberg, Stanfield, Ak-
Chin Village and Mobile.

This includes the following highways...
AZ Interstate 10 between mile markers 180 and 185.
AZ Interstate 8 between mile markers 144 and 163.
AZ Route 238 between mile markers 30 and 44.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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 3263 11224 3300 11230 3313 11228 3317 11203
      3303 11172 3276 11199 3276 11205 3272 11207
      3272 11214 3269 11215 3268 11220 3264 11220
TIME...MOT...LOC 2145Z 228DEG 23KT 3298 11211

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

INS

Local storm report, Sep 18, 2:48 PM MST, 1 hour 46 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
248 PM MST SAT SEP 18 2021

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

0237 PM     TSTM WND GST     2 SSE CHANDLER          33.26N 111.86W
09/18/2021  E45 MPH          MARICOPA           AZ   TRAINED SPOTTER

            A TRAINED SPOTTER NEAR ALMA SCHOOL RD. AND
            QUEEN CREEK RD. REPORTED SOME SMALL TREE
            BRANCHES/TWIGS SNAPPED AND VISIBILITY
            REDUCED TO NEAR ONE HALF MILE IN BLOWING
            DUST.

&&

AJ

Local storm report, Sep 18, 3:16 PM MST, 1 hour 18 minutes before

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Local storm report, Sep 18, 4:03 PM MST, 31 minutes before

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Local storm report, Sep 18, 4:10 PM MST, 24 minutes before

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Special weather statement, Sep 18, 4:34 PM MST, 0 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 17, 5:43 PM MST	Special Weather Statement	PSR	Yuma	32 min
Sep 18, 11:51 AM MST	Special Weather Statement	PSR	Maricopa	24 min
Sep 18, 12:13 PM MST	Areal Flood Advisory	PSR	Maricopa	22 min
Sep 18, 12:22 PM MST	Special Weather Statement	PSR	Maricopa	38 min
Sep 18, 12:35 PM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa, Pinal	4 hr
Sep 18, 12:48 PM MST	Special Weather Statement	PSR	Maricopa	27 min
Sep 18, 1:11 PM MST	Areal Flood Advisory	PSR	Maricopa	2 hr
Sep 18, 1:30 PM MST	Special Weather Statement	PSR	Maricopa	30 min
Sep 18, 1:39 PM MST	Special Weather Statement	PSR	Maricopa	66 min
Sep 18, 1:46 PM MST	Areal Flood Advisory	PSR	Maricopa	119 min
Sep 18, 2:05 PM MST	Special Weather Statement	PSR		25 min
Sep 18, 2:15 PM MST	Dust Storm Advisory	PSR	Maricopa, Pinal	45 min
Sep 18, 2:46 PM MST	Special Weather Statement	PSR		44 min
Sep 18, 2:54 PM MST	Dust Storm Advisory	PSR	Maricopa, Pinal	66 min
Sep 18, 3:00 PM MST	Severe Thunderstorm Warning	PSR	Maricopa, Pinal	45 min
Sep 18, 3:08 PM MST	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Sep 18, 3:17 PM MST	Dust Storm Warning	PSR	Maricopa, Pinal	43 min
Sep 18, 3:23 PM MST	Severe Thunderstorm Warning	PSR	Maricopa, Pinal	35 min
Sep 17, 5:09 PM MST	Special Weather Statement	PSR	Imperial	51 min
Sep 17, 5:41 PM MST	Areal Flood Advisory	PSR	Imperial, Riverside	2 hr

Nearby

Special Weather Statements in Arizona, 2021 Every special weather statement in 2021

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.