Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 112, NWS Phoenix, AZ

July 30, 2021Imperial County, California

NWS Phoenix, AZ issued this flash flood warning at Jul 30, 2021, 3:11 PM PDT for Imperial County, California. It was in force for 5 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 30, 2021, 3:11 PM PDT (22:11 UTC)
Expired
Jul 30, 2021, 8:15 PM PDT
In force
5 hr
Issued by
NWS Phoenix, AZ
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Imperial County, CA

The radar

The San Diego radar (KNKX), 105 km from the middle of the area, began a volume at 22:15 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

San Diego, CA (KNKX), launched 12:00Z, 10.2 hours before the alert went out and 118 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-pSkew-T log-p diagram, San Diego, CA at 12:00Z on 2021-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, San Diego, CA at 12:00Z on 2021-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -15 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2147 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-15 m²/s²
0-3 km storm-relative helicity
37 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

372 
WGUS55 KPSR 302211
FFWPSR
CAC025-310315-
/O.NEW.KPSR.FF.W.0112.210730T2211Z-210731T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
311 PM PDT Fri Jul 30 2021

The National Weather Service in Phoenix has issued a

* Flash Flood Warning for...
  Southwestern Imperial County in southeastern California...

* Until 815 PM PDT.

* At 311 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain south of the border. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts up to 1 inch are possible 
  in the warned area. Runoff from this rain will make its way north. 
  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...
  Ocotillo and Mountain Spring.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3270 11611 3276 11604 3273 11596 3271 11584
      3272 11569 3265 11572 3262 11611

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

MS
2 follow-up statements
313 
WGUS75 KPSR 310042
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
542 PM PDT Fri Jul 30 2021

CAC025-310315-
/O.CON.KPSR.FF.W.0112.000000T0000Z-210731T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Imperial CA-
542 PM PDT Fri Jul 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM PDT THIS 
EVENING FOR SOUTHWESTERN IMPERIAL COUNTY...

At 542 PM PDT, Doppler radar indicated between 1 and 2 inches of 
rain have fallen south of the border. This water will make its way 
north and likely impact portions of Imperial County. 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...
  Ocotillo and Mountain Spring.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3270 11611 3276 11604 3273 11596 3271 11584
      3272 11569 3265 11572 3262 11611

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

MS
109 
WGUS75 KPSR 310309
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
809 PM PDT Fri Jul 30 2021

CAC025-310319-
/O.EXP.KPSR.FF.W.0112.000000T0000Z-210731T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Imperial CA-
809 PM PDT Fri Jul 30 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 815 PM PDT THIS EVENING FOR 
SOUTHWESTERN IMPERIAL COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3270 11611 3276 11604 3273 11596 3271 11584
      3272 11569 3265 11572 3262 11611

$$

INS

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 2:01 PM PDTSpecial Weather StatementPSRImperial29 min
Jul 30, 3:45 PM PDTSpecial Weather StatementPSRRiverside30 min
Jul 30, 3:55 PM PDTFlash Flood Warning Considerable damage threatPSRRiverside, San Bernardino4 hr
Jul 30, 4:20 PM PDTSpecial Weather StatementPSRImperial25 min
Jul 30, 4:37 PM PDTSpecial Weather StatementPSRRiverside23 min
Jul 30, 4:48 PM PDTSpecial Weather StatementPSRImperial27 min

Nearby

Flash Flood Warnings in California, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.