Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 41, NWS San Diego, CA

September 10, 2012San Bernardino County, California

NWS San Diego, CA issued this flash flood warning at Sep 10, 2012, 1:29 PM PDT for San Bernardino County, California. It was in force for 3 hr. 2 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: Sep 10, 2012, 1:29 PM PDT (20:29 UTC)
Expired: Sep 10, 2012, 4:15 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 Santa Ana Mts radar (KSOX), 77 km from the middle of the area, began a volume at 20:31 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
Sep 10, 1:30 PM PDT	HEAVY RAIN 2.84	4 Nne San Gorgonio Moun, CA	HEART BAR...BETWEEN 1230-1330 PDT...MEASURED 2.84 INCHES OF RAIN.
Sep 10, 1:33 PM PDT	FLASH FLOOD	Forest Falls, CA	A MEMBER OF THE PUBLIC AFFILIATED WITH UC RIVERSIDE REPORTED 3 INCHES OF RAIN IN THE PAST HOUR AT THE YUCAIPA RIDGE WEATHER STATION. MILL CREEK RUNNING 100 FEET WIDE AT ONE POINT WITH DEBRIS. POLICE ARE BEGINNING TO EVACUATE SOME PEOPLE IN THE FOREST FALLS ARE

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

The nearest sounding before it

Edwards AFB, CA (KEDW), launched 12:00Z, 8.5 hours before the alert went out and 118 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: 2666 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 61 m²/s²
0-3 km storm-relative helicity: 75 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

931 
WGUS56 KSGX 102029
FFWSGX
CAC071-102315-
/O.NEW.KSGX.FF.W.0041.120910T2029Z-120910T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN DIEGO CA
129 PM PDT MON SEP 10 2012

THE NATIONAL WEATHER SERVICE IN SAN DIEGO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTH CENTRAL SAN BERNARDINO COUNTY IN SOUTHERN CALIFORNIA...

* UNTIL 415 PM PDT

* AT 118 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A 
STORM CAPABLE OF PRODUCING FLASH FLOODING OVER FOREST FALLS AND THE 
SURROUNDING MOUNTAIN AREAS SOUTH OF BIG BEAR. THIS STORM WAS NEARLY 
STATIONARY.    

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO FOREST   
FALLS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

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.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN SAN
DIEGO.

&&

LAT...LON 3419 11699 3425 11671 3404 11676 3404 11702

$$
JT

2 follow-up statements

925 
WGUS76 KSGX 102105
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
205 PM PDT MON SEP 10 2012

CAC071-102315-
/O.CON.KSGX.FF.W.0041.000000T0000Z-120910T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
205 PM PDT MON SEP 10 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO COUNTY...

AT 142 PM PDT...2 TO 3 INCHES OF RAIN HAS BEEN REPORTED AT THE LOCAL 
RAIN GAGES IN THE PAST TWO HOURS. CHP REPORTED DEBRIS AND FLOODING 
ALONG HIGHWAY 38 IN ANGELUS OAKS. THIS STORM WAS NEARLY STATIONARY 
OVER THE WARNED AREA AND WILL CONTINUE TO BE CAPABLE OF PRODUCING 
FLASH FLOODING ALONG MILL CREEK AND SURROUNDING STREAMS.     

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

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.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN SAN
DIEGO.

&&

LAT...LON 3419 11699 3425 11671 3404 11676 3404 11702

$$

JT

292 
WGUS76 KSGX 102309
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
409 PM PDT MON SEP 10 2012

CAC071-102315-
/O.EXP.KSGX.FF.W.0041.000000T0000Z-120910T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
409 PM PDT MON SEP 10 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 415 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO COUNTY...

HEAVY RAINFALL HAS ENDED OVER THE FOREST FALLS AND SAN GORGONIO 
AREA...AND SO THE FLASH FLOOD WARNING WILL BE ALLOWED TO EXPIRE. 
HOWEVER...LOCALIZED RUN-OFF WILL CONTINUE...AND IT IS POSSIBLE THAT 
MORE THUNDERSTORMS AND SHOWERS MAY DEVELOP OVER THIS AREA AGAIN AT 
SOME POINT THROUGH THIS EVENING.

LAT...LON 3419 11699 3425 11671 3404 11676 3404 11702

$$

HARRISON

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 9, 5:23 PM PDT	Severe Thunderstorm Warning	SGX	San Diego	45 min
Sep 9, 5:30 PM PDT	Flash Flood Warning	SGX	San Diego	104 min
Sep 9, 7:01 PM PDT	Flash Flood Watch	SGX	Riverside, San Bernardino, San Diego	23 hr
Sep 9, 7:26 PM PDT	Blowing Dust Advisory	SGX	Riverside, San Diego	3 hr
Sep 10, 12:21 PM PDT	Areal Flood Advisory	SGX	Riverside, San Bernardino	119 min
Sep 10, 1:17 PM PDT	Severe Thunderstorm Warning	SGX	Riverside	49 min
Sep 10, 2:00 PM PDT	Areal Flood Advisory	SGX	San Bernardino	3 hr
Sep 10, 2:33 PM PDT	Severe Thunderstorm Warning	SGX	Orange, Riverside	50 min
Sep 10, 2:42 PM PDT	Flash Flood Warning	SGX	San Diego	93 min
Sep 10, 2:59 PM PDT	Flash Flood Warning	SGX	San Bernardino	2 hr
Sep 10, 3:07 PM PDT	Special Weather Statement	SGX	Orange	53 min
Sep 10, 4:34 PM PDT	Areal Flood Advisory	SGX	San Bernardino	116 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.