Alert archive / Arizona / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 94, NWS Phoenix, AZ
NWS Phoenix, AZ issued this severe thunderstorm warning at Aug 18, 2021, 12:52 PM MST for Maricopa County, Arizona. It was in force for 53 min. 5 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 18, 2021, 12:52 PM MST (19:52 UTC)
- Expired
- Aug 18, 2021, 1:45 PM MST
- In force
- 53 min
- Issued by
- NWS Phoenix, AZ
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 60.0 mph
County Maricopa County, AZ
The radar
The Phoenix radar (KIWA), 53 km from the middle of the area, began a volume at 19:56 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 18, 1:15 PM MST | TSTM WND DMG | 4 N Paradise Valley, AZ | **DELAYED REPORT** REPORTS OF DOWNED TREES BETWEEN 56TH ST AND 70TH ST AROUND SHEA BLVD. |
| Aug 18, 1:20 PM MST | TSTM WND DMG | 5 Nnw Phoenix, AZ | **DELAYED REPORT** VERY LARGE TREES BLOWN OVER. TREE DIAMETER 12-18 INCHES AND HEIGHT OVER 30 FT. TIME BASED ON RADAR ESTIMATES W DOWNBURST. EST. ISOLATED WINDS 50-60 MPH, COMMON 30-40 MPH. |
| Aug 18, 1:38 PM MST | TSTM WND DMG | 6 Ene Glendale, AZ | ROOF DAMAGE FROM AN APARTMENT COMPLEX LANDED ON A CAR. |
| Aug 18, 1:40 PM MST | TSTM WND DMG | 4 Nne Glendale, AZ | **DELAYED REPORT** SPOTTER SHARED PICTURES OF A VERY LARGE UPROOTED TREES. ONE TREE FELL ONTO APARTMENT BUILDING AND THE OTHER ONTO A VEHICLE. DIAMETER OF THE TREES WERE AT LEAST 12-18 INCHES AND OVER 30 FEET HIGH. TIMING MATCHED DOWNBURST SIGNATURE ON RADAR. |
| Aug 18, 1:50 PM MST | HAIL 0.5 | 5 Ne Glendale, AZ | MOSTLY PEA SIZE HAIL BUT WITH A FEW UP TO 0.50 AN INCH. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Phoenix, AZ (KPSR), launched 12:00Z, 7.9 hours before the alert went out and 21 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.
- Mixed-layer CAPE
- 1239 J/kg
- Mixed-layer CIN
- -34 J/kg
- Mixed-layer LCL
- 1144 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- 52 m²/s²
- 0-3 km storm-relative helicity
- 40 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
624
WUUS55 KPSR 181952
SVRPSR
AZC013-182045-
/O.NEW.KPSR.SV.W.0094.210818T1952Z-210818T2045Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Phoenix AZ
1252 PM MST Wed Aug 18 2021
The National Weather Service in Phoenix has issued a
* Severe Thunderstorm Warning for...
Maricopa County in south central Arizona...
* Until 145 PM MST.
* At 1252 PM MST, a severe thunderstorm was located over Downtown
Peoria, or near Youngtown, moving northeast at 15 mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage
to roofs, siding, and trees.
* Locations impacted include...
Phoenix, Glendale, El Mirage, Paradise Valley, Youngtown, Sun City,
Glendale Sports Complex, Piestewa Peak Park, North Mountain Park,
Arizona State Fairgrounds, Downtown Peoria, Arrowhead Mall,
Downtown Glendale and Metro Center Mall.
This includes the following highways...
AZ Interstate 10 between mile markers 137 and 144.
AZ Interstate 17 between mile markers 200 and 216.
AZ Route 51 between mile markers 3 and 12.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 3341 11216 3357 11234 3374 11218 3358 11193
TIME...MOT...LOC 1952Z 230DEG 15KT 3356 11225
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
AD1 follow-up statement
087
WWUS55 KPSR 182012
SVSPSR
Severe Weather Statement
National Weather Service Phoenix AZ
112 PM MST Wed Aug 18 2021
AZC013-182045-
/O.CON.KPSR.SV.W.0094.000000T0000Z-210818T2045Z/
Maricopa AZ-
112 PM MST Wed Aug 18 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 145 PM MST
FOR MARICOPA COUNTY...
At 111 PM MST, a severe thunderstorm was located near Arrowhead Mall,
or near Glendale, moving northeast at 15 mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage to
roofs, siding, and trees.
Locations impacted include...
Phoenix, Glendale, El Mirage, Paradise Valley, Youngtown, Sun City,
Glendale Sports Complex, Piestewa Peak Park, North Mountain Park,
Arizona State Fairgrounds, Downtown Peoria, Arrowhead Mall, Downtown
Glendale and Metro Center Mall.
This includes the following highways...
AZ Interstate 10 between mile markers 137 and 144.
AZ Interstate 17 between mile markers 200 and 216.
AZ Route 51 between mile markers 3 and 12.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 3341 11216 3357 11234 3374 11218 3358 11193
TIME...MOT...LOC 2011Z 230DEG 15KT 3361 11217
HAIL...1.00IN
WIND...60MPH
$$
ADThe office that day
Everything else NWS Phoenix, AZ issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 5:16 PM MST | Flash Flood Warning | PSR | Gila | 6 hr |
| Aug 17, 6:05 PM MST | Flash Flood Warning | PSR | Gila | 6 hr |
| Aug 17, 9:08 PM MST | Flash Flood Watch | PSR | Gila, Maricopa, Pinal | 23 hr |
| Aug 18, 7:55 AM MST | Flash Flood Warning | PSR | Gila | 4 hr |
| Aug 18, 8:48 AM MST | Flash Flood Warning | PSR | Gila, Maricopa, Pinal | 6 hr |
| Aug 18, 9:26 AM MST | Flash Flood Warning | PSR | Gila, Pinal | 5 hr |
| Aug 18, 9:39 AM MST | Flash Flood Warning | PSR | Gila | 4 hr |
| Aug 18, 10:16 AM MST | Flash Flood Warning | PSR | Gila | 4 hr |
| Aug 18, 11:16 AM MST | Flash Flood Warning | PSR | Gila | 3 hr |
| Aug 18, 11:37 AM MST | Flash Flood Warning | PSR | Gila | 5 hr |
| Aug 18, 11:46 AM MST | Severe Thunderstorm Warning | PSR | Maricopa | 29 min |
| Aug 18, 11:59 AM MST | Flash Flood Warning | PSR | Maricopa | 5 hr |
| Aug 18, 12:16 PM MST | Severe Thunderstorm Warning | PSR | Maricopa | 29 min |
| Aug 18, 12:26 PM MST | Special Weather Statement | PSR | Maricopa | 49 min |
| Aug 18, 12:28 PM MST | Flash Flood Warning | PSR | Gila, Maricopa | 5 hr |
| Aug 18, 12:28 PM MST | Flash Flood Warning | PSR | Maricopa | 4 hr |
| Aug 18, 12:29 PM MST | Special Weather Statement | PSR | 46 min | |
| Aug 18, 12:38 PM MST | Special Weather Statement | PSR | 52 min | |
| Aug 18, 12:45 PM MST | Special Weather Statement | PSR | 45 min | |
| Aug 18, 1:00 PM MST | Severe Thunderstorm Warning | PSR | Maricopa | 45 min |
| Aug 18, 1:06 PM MST | Flash Flood Warning | PSR | Maricopa | 5 hr |
| Aug 18, 1:11 PM MST | Severe Thunderstorm Warning | PSR | Maricopa | 35 min |
| Aug 18, 1:19 PM MST | Special Weather Statement | PSR | Gila | 41 min |
| Aug 18, 1:23 PM MST | Flash Flood Warning | PSR | Maricopa | 4 hr |
| Aug 18, 1:39 PM MST | Special Weather Statement | PSR | Maricopa | 51 min |
| Aug 18, 1:40 PM MST | Flash Flood Warning | PSR | Maricopa | 6 hr |
| Aug 18, 1:46 PM MST | Flash Flood Warning | PSR | Maricopa | 4 hr |
| Aug 18, 1:47 PM MST | Special Weather Statement | PSR | 43 min | |
| Aug 18, 2:09 PM MST | Special Weather Statement | PSR | 51 min | |
| Aug 18, 2:13 PM MST | Special Weather Statement | PSR | Maricopa | 47 min |
| Aug 18, 2:15 PM MST | Flash Flood Warning | PSR | Maricopa | 6 hr |
| Aug 18, 2:29 PM MST | Severe Thunderstorm Warning | PSR | Gila, Maricopa | 46 min |
| Aug 18, 2:32 PM MST | Special Weather Statement | PSR | 43 min | |
| Aug 18, 2:34 PM MST | Special Weather Statement | PSR | Gila | 41 min |
| Aug 18, 2:45 PM MST | Flash Flood Warning | PSR | Gila, Maricopa | 6 hr |
| Aug 18, 3:02 PM MST | Special Weather Statement | PSR | 43 min | |
| Aug 18, 3:03 PM MST | Special Weather Statement | PSR | Pinal | 42 min |
| Aug 18, 3:11 PM MST | Flash Flood Warning | PSR | Gila, Maricopa | 5 hr |
| Aug 18, 3:19 PM MST | Special Weather Statement | PSR | 41 min | |
| Aug 18, 3:33 PM MST | Flash Flood Warning | PSR | Gila, Maricopa | 4 hr |
| Aug 18, 3:41 PM MST | Special Weather Statement | PSR | Gila | 64 min |
| Aug 18, 3:46 PM MST | Flash Flood Warning | PSR | Gila | 5 hr |
| Aug 18, 4:13 PM MST | Special Weather Statement | PSR | Maricopa | 47 min |
| Aug 18, 4:39 PM MST | Special Weather Statement | PSR | Maricopa | 51 min |
| Aug 18, 4:58 PM MST | Severe Thunderstorm Warning | PSR | Maricopa | 32 min |
Nearby
Severe Thunderstorm Warnings in Arizona, 2021Every severe thunderstorm warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.