Alert archive / Arizona / Flash Flood Warnings in 2021
Flash Flood Warning 249, NWS Phoenix, AZ
NWS Phoenix, AZ issued this flash flood warning at Sep 18, 2021, 12:35 PM MST for Maricopa County, Pinal County, Arizona. It was in force for 4 hr. 1 report 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
- Sep 18, 2021, 12:35 PM MST (19:35 UTC)
- Expired
- Sep 18, 2021, 4:45 PM MST
- In force
- 4 hr
- Issued by
- NWS Phoenix, AZ
- Area
- Storm-based polygon
- Damage threat
- Considerable
- Flood severity
- None
Counties Maricopa County, AZ, Pinal County, AZ
The radar
The Phoenix radar (KIWA), 76 km from the middle of the area, began a volume at 19:39 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 |
|---|---|---|---|
| Sep 18, 4:03 PM MST | FLASH FLOOD | 2 E Mobile, AZ | ***DELAYED REPORT*** VIDEO ON SOCIAL MEDIA SHOWED PART OF SR 238 APPEARING TO BE IMPASSABLE BETWEEN MP 33-35 DUE TO FLOODING. DPS ALSO RESPONDED TO A VEHICLE STALLED DUE TO FLOODING IN THIS AREA. |
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, 7.6 hours before the alert went out and 61 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
- 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
The text
As transmitted.
844
WGUS55 KPSR 181935
FFWPSR
AZC013-021-182345-
/O.NEW.KPSR.FF.W.0249.210918T1935Z-210918T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
1235 PM MST Sat Sep 18 2021
The National Weather Service in Phoenix has issued a
* Flash Flood Warning for...
Maricopa County in south central Arizona...
Pinal County in southeastern Arizona...
* Until 445 PM MST.
* At 1235 PM MST, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 0.5 and 1 inch of rain
has fallen. Additional rainfall amounts up to 0.5 inches are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.
HAZARD...Life threatening flash flooding. Thunderstorms
producing flash flooding.
SOURCE...Radar.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets and underpasses.
* Some locations that will experience flash flooding include...
Estrella, Sonoran National Monument, Estrella Sailport, Bosque and
Mobile.
This includes the following highways...
AZ Route 238 between mile markers 10 and 19.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3294 11263 3299 11265 3307 11247 3311 11227
3310 11214 3302 11213
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
INS3 follow-up statements
971
WGUS75 KPSR 182035
FFSPSR
Flash Flood Statement
National Weather Service Phoenix AZ
135 PM MST Sat Sep 18 2021
AZC013-021-182345-
/O.CON.KPSR.FF.W.0249.000000T0000Z-210918T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-Pinal AZ-
135 PM MST Sat Sep 18 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 PM MST THIS
AFTERNOON FOR MARICOPA AND PINAL COUNTIES...
At 135 PM MST, Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Between 0.5 and 1.25 inches of rain
have fallen. Additional rainfall amounts up to 0.5 inches are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.
HAZARD...Life threatening flash flooding. Thunderstorms producing
flash flooding.
SOURCE...Radar.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets and underpasses.
Some locations that will experience flash flooding include...
Estrella, Sonoran National Monument, Estrella Sailport, Bosque and
Mobile.
This includes the following highways...
AZ Route 238 between mile markers 10 and 19.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3294 11263 3299 11265 3307 11247 3311 11227
3310 11214 3302 11213
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
INS897
WGUS75 KPSR 182232
FFSPSR
Flash Flood Statement
National Weather Service Phoenix AZ
332 PM MST Sat Sep 18 2021
AZC013-021-182345-
/O.CON.KPSR.FF.W.0249.000000T0000Z-210918T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-Pinal AZ-
332 PM MST Sat Sep 18 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 PM MST THIS
AFTERNOON FOR MARICOPA AND PINAL COUNTIES...
At 332 PM MST, Doppler radar and automated rain gauges indicated
thunderstorms producing heavy rain across the warned area. Between 1
and 1.5 inches of rain have fallen. Flash flooding is ongoing or
expected to begin shortly.
HAZARD...Life threatening flash flooding. Thunderstorms producing
flash flooding.
SOURCE...Radar and automated gauges.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets and underpasses.
Some locations that will experience flash flooding include...
Estrella, Sonoran National Monument, Estrella Sailport, Bosque and
Mobile.
This includes the following highways...
AZ Route 238 between mile markers 10 and 19.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3294 11263 3299 11265 3307 11247 3311 11227
3310 11214 3302 11213
FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
INS067
WGUS75 KPSR 182342
FFSPSR
Flash Flood Statement
National Weather Service Phoenix AZ
442 PM MST Sat Sep 18 2021
AZC013-021-182352-
/O.EXP.KPSR.FF.W.0249.000000T0000Z-210918T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-Pinal AZ-
442 PM MST Sat Sep 18 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 445 PM MST THIS AFTERNOON FOR
MARICOPA AND PINAL COUNTIES...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
LAT...LON 3294 11263 3299 11265 3307 11247 3311 11227
3310 11214 3302 11213
$$
INSThe 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, 12:48 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 18, 4:34 PM MST | Special Weather Statement | PSR | Pinal | 41 min |
Nearby
Flash Flood Warnings in Arizona, 2021Every flash flood 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.