Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 7, NWS San Diego, CA

July 30, 2021Riverside County, San Diego County, California

NWS San Diego, CA issued this flash flood warning at Jul 30, 2021, 2:38 PM PDT for Riverside County, San Diego County, California. It was in force for 2 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, 2:38 PM PDT (21:38 UTC)
Expired
Jul 30, 2021, 5:00 PM PDT
In force
2 hr
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Flood severity
None

Counties Riverside County, CA, San Diego County, CA

The radar

The San Diego radar (KNKX), 64 km from the middle of the area, began a volume at 21:39 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.

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 9.6 hours before the alert went out and 81 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.

121 
WGUS56 KSGX 302138
FFWSGX
CAC065-073-310000-
/O.NEW.KSGX.FF.W.0007.210730T2138Z-210731T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Diego CA
238 PM PDT Fri Jul 30 2021

The National Weather Service in San Diego has issued a

* Flash Flood Warning for...
  Riverside County in southern California...
  North Central San Diego County in southwestern California...

* Until 500 PM PDT.

* At 238 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Additional rainfall amounts of 
  1 to 1.5 inches are possible in the warned area. Flash flooding is 
  ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Temecula, Anza, Hemet, Aguanga, Hwy 79 Between Oak Grove And 
  Aguanga, Palomar Mountain, Palomar Mountain State Park, Hwy 79 
  Between Warner Springs And Oak Grove, S7 - East Grade Rd, Oak 
  Grove, Sage, Cahuilla Indian Reservation, Pauma Valley, La Jolla 
  Indian Reservation, Lake Skinner Recreation Area and Winchester.

This includes the following streams and drainages...
  Doane Creek, Seco Creek, Arroyo, Cedar Creek, Harrison Canyon, San 
  Luis Rey River, Temecula Creek, Chihuahua Creek, Pauma Creek, West 
  Fork San Luis Rey River, Yuima Creek, Long Canyon, Kohler Canyon, 
  French Creek, Iron Spring Canyon, Potrero Creek, Cooper Canyon, 
  Lion Creek, Bear Canyon, Cow Canyon and Iron Springs Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3345 11696 3348 11698 3368 11710 3364 11671
      3343 11663 3339 11662 3326 11691

FLASH FLOOD...RADAR INDICATED

$$

Small
2 follow-up statements
062 
WGUS76 KSGX 302243
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
343 PM PDT Fri Jul 30 2021

CAC065-073-310000-
/O.CON.KSGX.FF.W.0007.000000T0000Z-210731T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-San Diego CA-
343 PM PDT Fri Jul 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 5 PM PDT THIS 
AFTERNOON FOR RIVERSIDE AND NORTH CENTRAL SAN DIEGO COUNTIES...

At 343 PM PDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Additional rainfall amounts of 0.5 to 1 
inch are possible in the warned area. Flash flooding is ongoing or 
expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Temecula, Anza, Hemet, Aguanga, Hwy 79 Between Oak Grove And 
  Aguanga, Palomar Mountain, Palomar Mountain State Park, Hwy 79 
  Between Warner Springs And Oak Grove, S7 - East Grade Rd, Oak 
  Grove, Sage, Cahuilla Indian Reservation, Pauma Valley, La Jolla 
  Indian Reservation, Lake Skinner Recreation Area and Winchester.

This includes the following streams and drainages...
  Doane Creek, Seco Creek, Arroyo, Cedar Creek, Harrison Canyon, San 
  Luis Rey River, Temecula Creek, Chihuahua Creek, Pauma Creek, West 
  Fork San Luis Rey River, Yuima Creek, Long Canyon, Kohler Canyon, 
  French Creek, Iron Spring Canyon, Potrero Creek, Cooper Canyon, 
  Lion Creek, Bear Canyon, Cow Canyon and Iron Springs Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3345 11696 3348 11698 3368 11710 3364 11671
      3343 11663 3339 11662 3326 11691

FLASH FLOOD...RADAR INDICATED

$$

Small
797 
WGUS76 KSGX 302355
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
455 PM PDT Fri Jul 30 2021

CAC065-073-310005-
/O.EXP.KSGX.FF.W.0007.000000T0000Z-210731T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-San Diego CA-
455 PM PDT Fri Jul 30 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 5 PM PDT THIS AFTERNOON FOR 
RIVERSIDE AND NORTH CENTRAL SAN DIEGO COUNTIES...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

LAT...LON 3345 11696 3348 11698 3368 11710 3364 11671
      3343 11663 3339 11662 3326 11691

$$

Small

The office that day

Everything else NWS San Diego, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 30, 1:41 PM PDTAreal Flood AdvisorySGXSan Bernardino4 hr
Jul 30, 2:48 PM PDTAreal Flood AdvisorySGXRiverside3 hr
Jul 30, 2:54 PM PDTAreal Flood AdvisorySGXSan Bernardino3 hr
Jul 30, 3:17 PM PDTSevere Thunderstorm WarningSGXRiverside58 min
Jul 30, 3:48 PM PDTFlash Flood Warning Considerable damage threatSGXRiverside3 hr

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.