Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 10, NWS San Diego, CA

July 31, 2012Riverside County, California

NWS San Diego, CA issued this flash flood warning at Jul 31, 2012, 2:26 PM PDT for Riverside County, California. It was in force for 109 min. 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: Jul 31, 2012, 2:26 PM PDT (21:26 UTC)
Expired: Jul 31, 2012, 4:15 PM PDT
In force: 109 min
Issued by: NWS San Diego, CA
Area: Storm-based polygon
Flood severity: None

County Riverside County, CA

The radar

The San Diego radar (KNKX), 119 km from the middle of the area, began a volume at 21:27 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
Jul 31, 3:00 PM PDT	FLASH FLOOD	Thousand Palms, CA	WATER FLOWING ACROSS ROADS IN THOUSAND PALMS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 9.4 hours before the alert went out and 139 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1285 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: -27 m²/s²
0-3 km storm-relative helicity: 72 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

865 
WGUS56 KSGX 312126
FFWSGX
CAC065-312315-
/O.NEW.KSGX.FF.W.0010.120731T2126Z-120731T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN DIEGO CA
226 PM PDT TUE JUL 31 2012

THE NATIONAL WEATHER SERVICE IN SAN DIEGO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  THE COACHELLA VALLEY IN CENTRAL RIVERSIDE COUNTY
  THIS INCLUDES THE CITIES OF...PALM SPRINGS...THOUSAND PALMS AND    
  INDIO...

* UNTIL 415 PM PDT

* AT 218 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS NEAR PALM SPRINGS AND THOUSAND PALMS MOVING SOUTHEAST 
DOWN THE VALLEY AT 20 MPH. HEAVY RAINS WILL MOVE OVER AREAS THAT 
RECEIVED HEAVY RAIN EARLIER TODAY. THESE AREAS WILL BE MOST 
SUSCEPTIBLE TO FLASH FLOODING. 

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO PALM
  DESERT...PALM DESERT...COACHELLA

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

&&

LAT...LON 3395 11642 3392 11629 3392 11620 3385 11613
      3383 11613 3376 11602 3374 11594 3352 11595
      3352 11605 3350 11607 3344 11604 3345 11617
      3358 11626 3373 11650 3390 11662 3398 11662
      3402 11647

$$

MOEDE

3 follow-up statements

925 
WGUS76 KSGX 312214
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
314 PM PDT TUE JUL 31 2012

CAC065-312315-
/O.CON.KSGX.FF.W.0010.000000T0000Z-120731T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
RIVERSIDE CA-
314 PM PDT TUE JUL 31 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM PDT FOR
CENTRAL RIVERSIDE COUNTY...

AT 305 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE VERY HEAVY RAIN MOVING SOUTH ACROSS THE VALLEY. STREET 
FLOODING IS LIKELY IN THOUSAND PALMS...PALM DESERT...INDIO AND LA 
QUINTA...THEN SPREAD TOWARD COACHELLA AND MECCA THROUGH 400 PM. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED 
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

&&

LAT...LON 3395 11642 3392 11629 3392 11620 3385 11613
      3383 11613 3376 11602 3374 11594 3352 11595
      3352 11605 3350 11607 3344 11604 3345 11617
      3358 11626 3373 11650 3390 11662 3398 11662
      3402 11647

$$

MOEDE

160 
WGUS76 KSGX 312247
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
347 PM PDT TUE JUL 31 2012

CAC065-312315-
/O.CON.KSGX.FF.W.0010.000000T0000Z-120731T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
RIVERSIDE CA-
347 PM PDT TUE JUL 31 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM PDT FOR
CENTRAL RIVERSIDE COUNTY...

AT 335 PM PDT...VERY HEAVY RAIN WAS FALLING OVER THE SOUTHERN 
SECTIONS OF THE VALLEY...THE SAME AREAS WHERE FLASH FLOODING 
OCCURRED EARLIER TODAY. 

THE STRONGEST STORMS WERE EAST OF INDIO AND COACHELLA OVER THE 
EASTERN SLOPES OF THE LITTLE SAN BERNARDINO MOUNTAINS. DILLON ROAD 
IS ESPECIALLY SUSCEPTIBLE TO FLASH FLOODING AND MUD FLOWS...AS IS 
FARGO CANYON ROAD AND THE COMMUNITIES BELOW FARGO CANYON.

HEAVY RAIN AND FLASH FLOODING WILL ALSO IMPACT INTERSTATE 10 EAST OF 
INDIO...AND BOX CANYON ROAD EAST OF MECCA THROUGH 415 PM. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

&&

LAT...LON 3395 11642 3392 11629 3392 11620 3385 11613
      3383 11613 3376 11602 3374 11594 3352 11595
      3352 11605 3350 11607 3344 11604 3345 11617
      3358 11626 3373 11650 3390 11662 3398 11662
      3402 11647

$$

MOEDE

742 
WGUS76 KSGX 312320
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
420 PM PDT TUE JUL 31 2012

CAC065-312325-
/O.EXP.KSGX.FF.W.0010.000000T0000Z-120731T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
RIVERSIDE CA-
420 PM PDT TUE JUL 31 2012

...THE FLASH FLOOD WARNING HAS EXPIRED FOR THE COACHELLA VALLEY...

THE HEAVIEST RAINS OVER MECCA AND OASIS OVER THE FAR SOUTHERN 
SECTIONS OF THE VALLEY WERE MOVING SOUTH OUT OF THE AREA.

EARLIER TODAY THE HEAVIEST RAIN FELL OVER THE EASTERN SECTIONS OF 
THE VALLEY WHERE FLASH FLOODING WAS REPORTED ON DILLON ROAD AND 
FARGO CANYON ROAD. 

LAT...LON 3395 11642 3392 11629 3392 11620 3385 11613
      3383 11613 3376 11602 3374 11594 3352 11595
      3352 11605 3350 11607 3344 11604 3345 11617
      3358 11626 3373 11650 3390 11662 3398 11662
      3402 11647

$$

MOEDE

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 30, 7:45 PM PDT	Flash Flood Watch	SGX	Riverside, San Bernardino, San Diego	23 hr
Jul 31, 11:51 AM PDT	Flash Flood Warning	SGX	Riverside	105 min
Jul 31, 1:23 PM PDT	Flash Flood Warning	SGX	San Diego	82 min

Nearby

Flash Flood Warnings in California, 2012 Every flash flood warning in 2012

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.