Alert archive / California / Flash Flood Warnings in 2018

Flash Flood Warning 3, NWS San Diego, CA

July 7, 2018San Bernardino County, California

NWS San Diego, CA issued this flash flood warning at Jul 7, 2018, 12:56 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 7, 2018, 12:56 PM PDT (19:56 UTC)
Expired: Jul 7, 2018, 4:00 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 Santa Ana Mts radar (KSOX), 75 km from the middle of the area, began a volume at 19:59 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, 7.9 hours before the alert went out and 152 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: 3366 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: -6 m²/s²
0-3 km storm-relative helicity: 3 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

930 
WGUS56 KSGX 071956
FFWSGX
CAC071-072300-
/O.NEW.KSGX.FF.W.0003.180707T1956Z-180707T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Diego CA
1256 PM PDT SAT JUL 7 2018

The National Weather Service in San Diego has issued a

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

* Until 400 PM PDT

* At 1253 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Flash flooding is expected.

* Some locations that will likely experience flooding include...
  Mount San Gorgonio, Forest Falls, Angelus Oaks, Hwy 38 Between 
  Yucaipa And Onyx Summit, Mountain Home Village,Barton Flats 
  Campground, Woodlands and Heart Bar Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Move away from recently burned areas. Life-threatening flooding of
creeks, roads and normally dry arroyos is likely. The heavy rains 
will likely trigger rock slides, mudslides and debris flows in steep 
terrain, especially in and around these areas.

&&

LAT...LON 3424 11679 3405 11682 3405 11696 3407 11712
      3425 11711

$$

Small

3 follow-up statements

218 
WGUS76 KSGX 072135
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
235 PM PDT SAT JUL 7 2018

CAC071-072300-
/O.CON.KSGX.FF.W.0003.000000T0000Z-180707T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
235 PM PDT SAT JUL 7 2018

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

At 230 PM PDT, Doppler radar indicated that the thunderstorms 
producing heavy rain had at least temporarily dissipated across the 
warned area. However, more thunderstorms could develop which will 
have the potential to do flooding through 400 PM over the San 
Bernardino Mountains between Big Bear Lake and Forest Falls.

Some locations that could experience flooding include...
Forest Falls, Highland, Big Bear Lake, Running Springs, Seven Oaks, 
Angelus Oaks, Hwy 38 Between Yucaipa And Onyx Summit, Hwy 18 Between 
Running Springs And Big Bear, Mentone, Hwy 38 Between Onyx Summit 
And Sugarloaf, Mountain Home Village, Green Valley Lake, Barton 
Flats Campground, Woodlands and Heart Bar Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Remain alert for flooding even in locations not receiving rain.
Arroyos, streams, and rivers can become raging killer currents in a
matter of minutes, even from distant rainfall.

Move away from recently burned areas. Life-threatening flooding of
creeks, roads and normally dry arroyos is likely. The heavy rains
will likely trigger rockslides, mudslides and debris flows in steep
terrain, especially in and around these areas.

&&

LAT...LON 3424 11679 3405 11682 3405 11696 3407 11712
      3425 11711

$$

Maxwell

521 
WGUS76 KSGX 072151
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
251 PM PDT SAT JUL 7 2018

CAC071-072300-
/O.CON.KSGX.FF.W.0003.000000T0000Z-180707T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
251 PM PDT SAT JUL 7 2018

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

At 234 PM PDT, a report of a mud flow 100 feet wide and 10 feet deep 
over Highway 38 about 1/2 mile north of the Forest Falls junction.

At 249 PM PDT, Doppler radar indicated that the thunderstorms 
producing heavy rain had at least temporarily dissipated across the 
warned area. However, more thunderstorms could develop which will 
have the potential to do flooding through 400 PM over the San 
Bernardino Mountains between Big Bear Lake and Forest Falls.

Some locations that could experience flooding include...
Forest Falls, Highland, Big Bear Lake, Running Springs, Seven Oaks, 
Angelus Oaks, Hwy 38 Between Yucaipa And Onyx Summit, Hwy 18 Between 
Running Springs And Big Bear, Mentone, Hwy 38 Between Onyx Summit 
And Sugarloaf, Mountain Home Village, Green Valley Lake, Barton 
Flats Campground, Woodlands and Heart Bar Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Remain alert for flooding even in locations not receiving rain.
Arroyos, streams, and rivers can become raging killer currents in a
matter of minutes, even from distant rainfall.

Move away from recently burned areas. Life-threatening flooding of
creeks, roads and normally dry arroyos is likely. The heavy rains
will likely trigger rockslides, mudslides and debris flows in steep
terrain, especially in and around these areas.

&&

LAT...LON 3424 11679 3405 11682 3405 11696 3407 11712
      3425 11711

$$

Maxwell

026 
WGUS76 KSGX 072255
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
355 PM PDT SAT JUL 7 2018

CAC071-072303-
/O.EXP.KSGX.FF.W.0003.000000T0000Z-180707T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
355 PM PDT SAT JUL 7 2018

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

Isolated showers and thunderstorms were occurring shortly before 400 
PM south of Big Bear Lake, but rainfall was light to moderate. 
Flooding is no longer expected to pose a threat.

LAT...LON 3424 11679 3405 11682 3405 11696 3407 11712
      3425 11711

$$

Maxwell

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 12:43 PM PDT	Flash Flood Warning	SGX	San Bernardino	3 hr
Jul 7, 2:07 PM PDT	Flash Flood Warning	SGX	Riverside, San Diego	3 hr

Nearby

Flash Flood Warnings in California, 2018 Every 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.