Alert archive / California / Flash Flood Warnings in 2011

Flash Flood Warning 9, NWS Reno, NV

September 12, 2011Lassen County, California

NWS Reno, NV issued this flash flood warning at Sep 12, 2011, 5:58 PM PDT for Lassen County, California. It was in force for 88 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Sep 12, 2011, 5:58 PM PDT (00:58 UTC)
Expired: Sep 12, 2011, 7:26 PM PDT
In force: 88 min
Issued by: NWS Reno, NV
Area: Storm-based polygon
Flood severity: None

County Lassen County, CA

The radar

The Medford radar (KMAX), 169 km from the middle of the area, began a volume at 00:57 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

Medford/Jackson, OR (KMFR), launched 00:00Z, 1.0 hours before the alert went out and 196 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: 3837 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: -13 m²/s²
0-3 km storm-relative helicity: 18 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.

966 
WGUS55 KREV 130058
FFWREV
CAC035-130300-
/O.NEW.KREV.FF.W.0009.110913T0058Z-110913T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE RENO NV
558 PM PDT MON SEP 12 2011

THE NATIONAL WEATHER SERVICE IN RENO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHWESTERN LASSEN COUNTY IN NORTHERN CALIFORNIA...
  THIS INCLUDES THE CITIES OF...NUBIEBER...BIEBER...

* UNTIL 800 PM PDT

* AT 552 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  THUNDERSTORMS CAPABLE OF PRODUCING FLASH FLOODING ALONG A LINE
  EXTENDING FROM BIEBER TO 7 MILES SOUTH OF NUBIEBER...MOVING WEST
  AT 5 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO CA
  299 AT SHASTA-LASSEN CO LINE AND PITTVILLE.

DOPPLER RADAR RAINFALL ESTIMATES OF UP TO 1.50 INCHES OF RAIN HAVE 
FALLEN OVER THIS AREA IN THE LAST HOUR. THE SLOW MOVING NATURE OF 
THESE STORMS ALONG WITH EXPECTED ADDITIONAL RAINS OF AROUND 1 INCH 
MAY PRODUCE FLASH FLOODING OR PONDING OF WATER IN LOW LYING AREAS IN 
THE BIG VALLEY AND ALONG THE HILLS ON THE SOUTHERN EDGE OF THE 
VALLEY.  FREQUENT LIGHTNING IS ALSO OCCURRING WITH THESE STORMS.

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

LAT...LON 4119 12111 4095 12110 4089 12131 4117 12134

$$

1 follow-up statement

090 
WGUS75 KREV 130226
FFSREV

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE RENO NV
726 PM PDT MON SEP 12 2011

CAC035-130234-
/O.CAN.KREV.FF.W.0009.000000T0000Z-110913T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LASSEN CA-
726 PM PDT MON SEP 12 2011

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR NORTHWESTERN LASSEN
COUNTY...

THE THREAT FOR CONTINUED FLASH FLOODING HAS DIMINISHED. REMEMBER THAT
MINOR FLOODING OR RUNOFF MAY CONTINUE IN LOW SPOTS FOR SEVERAL HOURS.

LAT...LON 4119 12111 4095 12110 4089 12131 4117 12134

$$

MYRICK

The office that day

Everything else NWS Reno, NV issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 12, 5:11 PM PDT	Special Weather Statement	REV	Lassen	34 min
Sep 12, 5:28 PM PDT	Severe Thunderstorm Warning	REV	Lassen	32 min
Sep 13, 1:53 AM PDT	Flash Flood Watch	REV	Alpine, El Dorado, Lassen, Mono, Nevada, Placer and 2 more	20 hr

Nearby

Flash Flood Warnings in California, 2011 Every flash flood warning in 2011

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.