Alert archive / California / Flash Flood Warnings in 2012
Flash Flood Warning 17, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this flash flood warning at Dec 23, 2012, 7:04 PM PST for San Mateo County, Santa Cruz County, California. It was in force for 86 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
- Dec 23, 2012, 7:04 PM PST (03:04 UTC)
- Expired
- Dec 23, 2012, 8:30 PM PST
- In force
- 86 min
- Issued by
- NWS San Francisco Bay Area, CA
- Area
- Storm-based polygon
- Flood severity
- None
Counties San Mateo County, CA, Santa Cruz County, CA
The radar
The San Francisco radar (KMUX), 41 km from the middle of the area, began a volume at 03:05 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
Oakland, CA (KOAK), launched 00:00Z, 3.1 hours before the alert went out and 57 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
- 6 J/kg
- Mixed-layer CIN
- -11 J/kg
- Mixed-layer LCL
- 487 m above ground
- 0-6 km bulk shear
- 69 kt
- 0-1 km storm-relative helicity
- 252 m²/s²
- 0-3 km storm-relative helicity
- 284 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted, in the capitals the NWS used until 2016.
046
WGUS56 KMTR 240304
FFWMTR
CAC081-087-240430-
/O.NEW.KMTR.FF.W.0017.121224T0304Z-121224T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
704 PM PST SUN DEC 23 2012
THE NATIONAL WEATHER SERVICE IN THE SAN FRANCISCO BAY AREA HAS
ISSUED A
* FLASH FLOOD WARNING FOR...
SAN MATEO COUNTY IN WESTERN CALIFORNIA...
SANTA CRUZ COUNTY IN WESTERN CALIFORNIA...
* UNTIL 830 PM PST.
* AT 700 PM PST...PESCADERO CREEK NEAR PESCADERO IS CURRENTLY
REPORTING STREAM FLOW LEVELS ABOVE FLOOD STAGE. RADAR IS INDICATING
ADDITIONAL RAINFALL IN THE AREA SO ADDITIONAL MINOR RISES ARE
POSSIBLE.
* LOCATIONS IN THE WARNING AREA INCLUDE THE TOWN OF PESCADERO AS
WELL AS ROADS AND TRAILS IN BUTANO STATE PARK. OTHER COASTAL
CREEKS IN THE AREA MAY BE IN FLOOD AS WELL.
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.
BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. 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 3737 12241 3739 12223 3716 12222 3713 12235
3715 12237 3716 12237 3718 12240 3720 12242
$$
STRUDLEY/DYKEMA/BELL1 follow-up statement
395
WGUS76 KMTR 240439
FFSMTR
FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
839 PM PST SUN DEC 23 2012
CAC081-087-240442-
/O.EXP.KMTR.FF.W.0017.000000T0000Z-121224T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SANTA CRUZ CA-SAN MATEO CA-
839 PM PST SUN DEC 23 2012
...THE FLASH FLOOD WARNING FOR THE PESCADERO CREEK IN SAN MATEO
COUNTY AND OTHER SMALL STREAMS AND CREEKS IN SAN MATEO AND SANTA
CRUZ COUNTIES HAS BEEN ALLOWED TO EXPIRE...
AT 830 PM PST A STREAM GAGE ON THE PESCADERO CREEK INDICATED THAT
THE WATER LEVEL ON THE PESCADERO CREEK WAS RAPIDLY FALLING. IN
ADDITION...RAINFALL HAD ENDED ACROSS THE AREA AND LITTLE ADDITIONAL
RAIN IS EXPECTED ACROSS SAN MATEO AND SANTA CRUZ COUNTIES FOR THE
REMAINDER OF THE EVENING. THEREFORE THE FLASH FLOOD WARNING HAS BEEN
ALLOWED TO EXPIRE.
MINOR FLOODING WILL CONTINUE ACROSS SAN MATEO AND SANTA CRUZ COUNTY
FOR THE REMAINDER OF THE EVENING AS RUNOFF FROM HEAVY RAIN TODAY
SLOWLY RECEDES. IN ADDITION...SHALLOW LANDSLIDES AND DEBRIS FLOWS
MAY OCCUR IN AREAS OF STEEP TERRAIN FOR SEVERAL HOURS AFTER RAINFALL
HAS ENDED.
LAT...LON 3737 12241 3739 12223 3716 12222 3713 12235
3715 12237 3716 12237 3718 12240 3720 12242
$$
DYKEMAThe office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 23, 4:04 PM PST | Areal Flood Advisory | MTR | Alameda, San Mateo, Santa Clara, Santa Cruz | 3 hr |
| Dec 23, 4:43 PM PST | Flash Flood Warning | MTR | Santa Cruz | 2 hr |
| Dec 23, 5:05 PM PST | Flash Flood Warning | MTR | San Mateo, Santa Cruz | 115 min |
| Dec 23, 7:01 PM PST | Flash Flood Warning | MTR | Santa Cruz | 108 min |
| Dec 23, 7:30 PM PST | Areal Flood Warning | MTR | San Mateo, Santa Clara | 105 min |
| Dec 23, 8:11 PM PST | Areal Flood Advisory | MTR | Monterey, San Benito, Santa Clara, Santa Cruz | 94 min |
| Dec 24, 2:41 PM PST | Small Craft Advisory | MTR | 3 days |
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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.