Alert archive / California / Flash Flood Warnings in 2020

Flash Flood Warning 2, NWS San Diego, CA

March 12, 2020Riverside County, California

NWS San Diego, CA issued this flash flood warning at Mar 12, 2020, 12:59 PM PDT for Riverside County, California. It was in force for 3 hr. 4 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
Mar 12, 2020, 12:59 PM PDT (19:59 UTC)
Expired
Mar 12, 2020, 4:00 PM PDT
In force
3 hr
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Flood severity
None

County Riverside County, CA

The radar

The San Diego radar (KNKX), 117 km from the middle of the area, began a volume at 20:01 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

TimeReportWhereRemark
Mar 12, 1:01 PM PDTHEAVY RAIN 0.5La Quinta, CAHEAVY RAIN AND THUNDERSTORM.
Mar 12, 1:20 PM PDTFLOOD5 Wnw Mecca, CAFLOODED ROADS REPORTED BY HIGHWAY PATROL AND CALTRANS ON 62ND AVENUE AND POLK - HEAVY RAIN AND THUNDERSTORMS IN THE AREA WITH RATES OF 0.50 PER HOUR.
Mar 12, 2:00 PM PDTFLOOD8 Nne Mecca, CACHP REPORTS FLOODING ON INTERSTATE 10 A FEW MILES WEST OF CACTUS CITY.
Mar 12, 2:35 PM PDTFLASH FLOOD4 Ene Indio, CAVEHICLE STUCK IN MUD ON DILLON RD.

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, 8.0 hours before the alert went out and 136 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 2020-03-12Temperature 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 2020-03-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 55 square meters per square second.1939587897117136Sfc1 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
968 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
55 m²/s²
0-3 km storm-relative helicity
145 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

691 
WGUS56 KSGX 121959
FFWSGX
CAC065-122300-
/O.NEW.KSGX.FF.W.0002.200312T1959Z-200312T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Diego CA
1259 PM PDT Thu Mar 12 2020

The National Weather Service in San Diego has issued a

* Flash Flood Warning for...
  Riverside County in southern California...

* Until 400 PM PDT.

* At 1254 PM PDT, NWS weather radar indicated widespread rainfall 
  and isolated thunderstorms producing heavy rain in the lower 
  Coachella Valley. Storms are slowly moving northward. Rainfall 
  rates of 0.25 to 0.50 inches per hour are occurring. Thunderstorms 
  will produce up to 0.60 inches per hour. This will cause dangerous 
  flash flooding to creeks and low lying areas. Roadways will have 
  significant ponding of water. Interstate 10 could be affected by 
  flooding. 

* Some locations that will experience flooding include...
  Indio, Palm Springs, Coachella, southeastern Anza, Cathedral City,
  Palm Desert, southeastern Desert Hot Springs, Rancho Mirage, Hwy 74
  Between Anza And Palm Desert and Thermal.

LAT...LON 3352 11596 3352 11605 3350 11608 3345 11604
      3344 11606 3345 11607 3342 11607 3343 11660
      3382 11658 3398 11644 3395 11642 3392 11629
      3392 11620 3386 11613 3382 11611 3375 11601
      3374 11595 3355 11594

$$

Tardy
1 follow-up statement
011 
WGUS76 KSGX 122217
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
317 PM PDT Thu Mar 12 2020

CAC065-122300-
/O.CON.KSGX.FF.W.0002.000000T0000Z-200312T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-
317 PM PDT Thu Mar 12 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 PM PDT FOR
RIVERSIDE COUNTY...

At 311 PM PDT, heavy rainfall continues near Indio but beginning to 
taper off over the lower Coachella Valley. Significant flooding will 
continue with runoff into the Whitewater river. Up to an inch of 
rainfall has occurred in the valley and reports of flooded roads. 

Some locations that will experience flooding include...
Indio, Palm Springs, Coachella, southeastern Anza, Cathedral City,
Palm Desert, southeastern Desert Hot Springs, Rancho Mirage, Hwy 74
Between Anza And Palm Desert and Thermal.

LAT...LON 3352 11596 3352 11605 3350 11608 3345 11604
      3344 11606 3345 11607 3342 11607 3343 11660
      3382 11658 3398 11644 3395 11642 3392 11629
      3392 11620 3386 11613 3382 11611 3375 11601
      3374 11595 3355 11594

$$

Tardy

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 12, 10:01 AM PDTAreal Flood AdvisorySGXRiverside, San Diego6 hr
Mar 12, 10:39 AM PDTAreal Flood AdvisorySGXOrange, Riverside, San Diego3 hr
Mar 12, 11:54 AM PDTFlash Flood WarningSGXSan Diego3 hr
Mar 12, 12:31 PM PDTAreal Flood AdvisorySGXOrange, Riverside, San Bernardino6 hr
Mar 12, 2:22 PM PDTFlash Flood WarningSGXOrange, Riverside, San Bernardino3 hr
Mar 12, 2:50 PM PDTAreal Flood AdvisorySGXSan Bernardino5 hr
Mar 12, 3:43 PM PDTWinter Weather AdvisorySGXRiverside, San Bernardino17 hr
Mar 12, 4:51 PM PDTFlash Flood WarningSGXSan Bernardino3 hr

Nearby

Flash Flood Warnings in California, 2020Every flash flood warning in 2020

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.