Alert archive / California / Flash Flood Warnings in 2018

Flash Flood Warning 13, NWS San Diego, CA

July 29, 2018San Bernardino County, California

NWS San Diego, CA issued this flash flood warning at Jul 29, 2018, 3:16 PM PDT for San Bernardino County, California. It was in force for 3 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 29, 2018, 3:16 PM PDT (22:16 UTC)
Expired
Jul 29, 2018, 6:15 PM PDT
In force
3 hr
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Flood severity
None

County San Bernardino County, CA

The radar

The Edwards AFB radar (KEYX), 80 km from the middle of the area, began a volume at 22:19 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, 10.3 hours before the alert went out and 212 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 2018-07-29Temperature 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 2018-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 23 square meters per square second.1939Sfc1 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
1375 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
23 m²/s²
0-3 km storm-relative helicity
59 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

874 
WGUS56 KSGX 292216
FFWSGX
CAC071-300115-
/O.NEW.KSGX.FF.W.0013.180729T2216Z-180730T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Diego CA
316 PM PDT SUN JUL 29 2018

The National Weather Service in San Diego has issued a

* Flash Flood Warning for...
  San Bernardino County in southern California...

* Until 615 PM PDT

* At 314 PM PDT, radar was tracking a large thunderstorm producing 
  very heavy rain across the warned area. Up to three inches of rain 
  have already fallen. Flash flooding will likely begin shortly. 

* Some locations that will likely experience flooding include...
  Rural areas east of Apple Valley and south of Daggett. 

Excessive rainfall over the warned area will likely cause mud slides
near steep terrain. The mud slide can consist of rock, mud,
vegetation and other loose materials.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3476 11671 3455 11671 3455 11705 3478 11705

$$

JMB
2 follow-up statements
679 
WGUS76 KSGX 292254
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
354 PM PDT SUN JUL 29 2018

CAC071-300115-
/O.CON.KSGX.FF.W.0013.000000T0000Z-180730T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
354 PM PDT SUN JUL 29 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM PDT FOR SAN
BERNARDINO COUNTY...

At 352 PM PDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Up to 5 inches of rain have already 
fallen in the warned area. Flash flooding will likely begin shortly.

Excessive rainfall over the warned area will likely cause mud slides
near steep terrain. The mud slide can consist of rock, mud,
vegetation and other loose materials.

Some locations that will experience likely flooding include...
NE of Apple Valley and northern Lucerne Valley and S of Daggett and 
Interstate 40. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3476 11671 3455 11671 3455 11705 3478 11705

$$

JMB
827 
WGUS76 KSGX 300107
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
607 PM PDT SUN JUL 29 2018

CAC071-300115-
/O.EXP.KSGX.FF.W.0013.000000T0000Z-180730T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
607 PM PDT SUN JUL 29 2018

...THE FLASH FLOOD WARNING FOR SAN BERNARDINO COUNTY WILL EXPIRE AT
615 PM PDT...

The heavy rain has ended. Please continue to heed any remaining road 
closures. Additional showers in the area could exacerbate any 
ongoing flooding problems. 

LAT...LON 3476 11671 3455 11671 3455 11705 3478 11705

$$

JMB

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 29, 2:59 PM PDTSevere Thunderstorm WarningSGXSan Diego61 min

Nearby

Flash Flood Warnings in California, 2018Every flash flood warning in 2018

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.