Alert archive / California / Flash Flood Warnings in 2012
Flash Flood Warning 7, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this flash flood warning at Dec 2, 2012, 7:41 AM PST for Sonoma County, California. It was in force for 64 min. 1 report 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
- Dec 2, 2012, 7:41 AM PST (15:41 UTC)
- Expired
- Dec 2, 2012, 8:45 AM PST
- In force
- 64 min
- Issued by
- NWS San Francisco Bay Area, CA
- Area
- Storm-based polygon
- Flood severity
- None
County Sonoma County, CA
The radar
The Sacramento radar (KDAX), 87 km from the middle of the area, began a volume at 15:42 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 |
|---|---|---|---|
| Dec 2, 7:41 AM PST | FLOOD | Petaluma, CA | WILLOW BROOK AT PENNGROVE PARK FLOODING |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Oakland, CA (KOAK), launched 12:00Z, 3.7 hours before the alert went out and 69 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.
- Mixed-layer CAPE
- 58 J/kg
- Mixed-layer CIN
- -1 J/kg
- Mixed-layer LCL
- 529 m above ground
- 0-6 km bulk shear
- 61 kt
- 0-1 km storm-relative helicity
- 203 m²/s²
- 0-3 km storm-relative helicity
- 348 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
The text
As transmitted, in the capitals the NWS used until 2016.
382 WGUS56 KMTR 021541 FFWMTR CAC097-021645- /O.NEW.KMTR.FF.W.0007.121202T1541Z-121202T1645Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ BULLETIN - EAS ACTIVATION REQUESTED FLASH FLOOD WARNING NATIONAL WEATHER SERVICE SAN FRANCISCO CA 741 AM PST SUN DEC 2 2012 THE NATIONAL WEATHER SERVICE IN THE SAN FRANCISCO BAY AREA HAS ISSUED A * FLASH FLOOD WARNING FOR... SONOMA COUNTY IN WESTERN CALIFORNIA... THIS INCLUDES THE CITY OF PETALUMA... * UNTIL 845 AM PST. * AT 735 AM PST...NWS DOPPLER RADAR AND AUTOMATED RAIN GAGES INDICATED SHARP RISES PRODUCING FLOODING ON THE WILLOW BROOK AT PENNGROVE PARK. * THE STORM PRODUCING WILL OTHERWISE REMAIN OVER MAINLY RURAL AREAS OF THE INDICATED COUNTY. A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS IMMINENT. RUNOFF FROM HEAVY RAINFALL WILL CAUSE LOCALIZED FLOODING OF SMALL CREEKS AND STREAMS AS WELL AS ROADWAYS...UNDERPASSES AND OTHER LOW LYING SPOTS. DO NOT ATTEMPT TO CROSS SWIFTLY FLOWING WATER OR WATER OF UNKNOWN DEPTH. TURN AROUND...DONT DROWN. IT IS IMPORTANT FOR CAMPERS AND HIKERS TO KNOW WHERE THEY ARE RELATIVE TO CREEKS...STREAMS...OR RIVERS WHICH CAN BECOME DANGEROUS IN HEAVY RAINS. BE PARTICULARLY AWARE IN HILLY TERRAIN WHERE MANY LOW WATER CROSSINGS CAN QUICKLY BECOME KILLERS. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING. TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE. LAT...LON 3828 12267 3829 12261 3822 12253 3819 12263 $$ JOHNSON
The office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 1, 4:44 PM PST | River Flood Watch | MTR | Sonoma | 6 days |
| Dec 2, 1:28 AM PST | Gale Warning | MTR | 11 hr | |
| Dec 2, 6:35 AM PST | Flash Flood Warning | MTR | Napa, Sonoma | 85 min |
| Dec 2, 6:54 AM PST | Areal Flood Advisory | MTR | Marin, Napa, Sonoma | 3 hr |
| Dec 2, 7:19 AM PST | Areal Flood Advisory | MTR | Alameda, Contra Costa, Marin, City and County of San Francisco, San Mateo, Santa Clara and 1 more | 3 hr |
| Dec 2, 8:15 AM PST | Flash Flood Warning | MTR | Santa Clara, Santa Cruz | 2 hr |
| Dec 2, 8:42 AM PST | Flash Flood Warning | MTR | Marin | 93 min |
| Dec 2, 8:47 AM PST | Flash Flood Warning | MTR | Sonoma | 88 min |
| Dec 2, 9:20 AM PST | Areal Flood Advisory | MTR | Monterey, San Benito, San Mateo, Santa Clara, Santa Cruz | 3 hr |
| Dec 2, 10:21 AM PST | Areal Flood Advisory | MTR | Alameda, Santa Clara | 54 min |
Nearby
Flash Flood Warnings in California, 2012Every 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.