Alert archive / California / Flash Flood Warnings in 2012
Flash Flood Warning 13, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this flash flood warning at Dec 23, 2012, 2:38 PM PST for Santa Cruz County, California. It was in force for 5 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
- Dec 23, 2012, 2:38 PM PST (22:38 UTC)
- Expired
- Dec 23, 2012, 8:00 PM PST
- In force
- 5 hr
- Issued by
- NWS San Francisco Bay Area, CA
- Area
- Storm-based polygon
- Flood severity
- None
County Santa Cruz County, CA
The radar
The San Francisco radar (KMUX), 20 km from the middle of the area, began a volume at 22:38 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 12:00Z, 10.6 hours before the alert went out and 78 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
- 5 J/kg
- Mixed-layer CIN
- -19 J/kg
- Mixed-layer LCL
- 833 m above ground
- 0-6 km bulk shear
- 62 kt
- 0-1 km storm-relative helicity
- 178 m²/s²
- 0-3 km storm-relative helicity
- 210 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
908 WGUS56 KMTR 232238 FFWMTR CAC087-240230- /O.NEW.KMTR.FF.W.0013.121223T2238Z-121224T0230Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ BULLETIN - EAS ACTIVATION REQUESTED FLASH FLOOD WARNING NATIONAL WEATHER SERVICE SAN FRANCISCO CA 238 PM PST SUN DEC 23 2012 THE NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA HAS ISSUED A * FLASH FLOOD WARNING FOR... SANTA CRUZ COUNTY IN WESTERN CALIFORNIA... * UNTIL 630 PM PST. * AT 200 PM PST...TRAINED WEATHER SPOTTERS REPORTED THAT THE SAN LORENZO RIVER AT BIG TREES WAS RISING AT THE RATE OF 4 FEET PER HOUR. RADAR CURRENTLY SHOWS AN AREA OF HEAVY RAIN MOVING INTO THE SANTA CRUZ MOUNTAINS WHICH WILL PRODUCE ADDITIONAL RUNOFF. AT 2:30 PM PST THE RIVER STAGE AT BIG TREES WAS 15.5 FEET AND RISING RAPIDLY. UNOFFICIAL FLOOD STAGE AT BIG TREES IS 17 FEET. * ADDITIONAL HEAVY RAIN IS EXPECTED OVER THE NEXT HOUR. A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS IMMINENT. RUNOFF FROM HEAVY RAINFALL WILL CAUSE LOCALIZED FLOODING OF THE FELTON GROVE AREA AND ADJACENT EQUESTRIAN FACILITIES AND PORTIONS OF THE FELTON COVERED BRIDGE PARK. BE ESPECIALLY CAREFUL AS WELL ON TRAILS IN THE HENRY COWELL REDWOODS STATE PARK. 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 3706 12213 3709 12204 3699 12201 3698 12206 $$ DYKEMA/STRUDLEY
2 follow-up statements
120 WGUS56 KMTR 240226 FFWMTR CAC087-240400- /O.EXT.KMTR.FF.W.0013.000000T0000Z-121224T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ BULLETIN - EAS ACTIVATION REQUESTED FLASH FLOOD WARNING NATIONAL WEATHER SERVICE SAN FRANCISCO CA 626 PM PST SUN DEC 23 2012 THE NATIONAL WEATHER SERVICE IN THE SAN FRANCISCO BAY AREA HAS EXTENDED THE * FLASH FLOOD WARNING FOR... SANTA CRUZ COUNTY IN WESTERN CALIFORNIA... * UNTIL 800 PM PST. * AT 620 PM PST THE SAN LORENZO RIVER STREAM GAGE AT BIG TREES REPORTED A STAGE ONE AND A HALF FEET OVER FLOOD STAGE. THE RIVER WAS BEGINNING TO SUBSIDE AND RAINFALL HAD DECREASED CONSIDERABLY OVER THE AREA. HOWEVER...FLOOD WATERS WILL TAKE SOME TIME TO RECEDE AND FLOODING IS LIKELY TO CONTINUE IN THE FELTON AREA FOR AT LEAST ANOTHER HOUR. * LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO FELTON A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS IMMINENT. RUNOFF FROM HEAVY RAINFALL WILL CAUSE LOCALIZED FLOODING OF SMALL CREEKS AND STREAMS AS WELL AS ROADWAYS...UNDERPASSES AND OTHER LOW LYING SPOTS. DO NOT ATTEMPT TO CROSS SWIFTLY FLOWING WATER OR WATER OF UNKNOWN DEPTH. TURN AROUND...DONT DROWN. IT IS IMPORTANT FOR CAMPERS AND HIKERS TO KNOW WHERE THEY ARE RELATIVE TO CREEKS...STREAMS...OR RIVERS WHICH CAN BECOME DANGEROUS IN HEAVY RAINS. BE PARTICULARLY AWARE IN HILLY TERRAIN WHERE MANY LOW WATER CROSSINGS CAN QUICKLY BECOME KILLERS. BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING. TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE. LAT...LON 3706 12213 3709 12204 3699 12201 3698 12206 $$ DYKEMA
484 WGUS76 KMTR 240408 FFSMTR FLASH FLOOD STATEMENT NATIONAL WEATHER SERVICE SAN FRANCISCO CA 808 PM PST SUN DEC 23 2012 CAC087-240412- /O.EXP.KMTR.FF.W.0013.000000T0000Z-121224T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ SANTA CRUZ CA- 808 PM PST SUN DEC 23 2012 ...THE FLASH FLOOD WARNING HAS EXPIRED FOR THE SAN LORENZO RIVER IN SANTA CRUZ COUNTY... AT 8 PM PST...THE STREAM GAGE ON THE SAN LORENZO RIVER AT BIG TREES HAD FALLEN BELOW FLOOD STAGE AND WAS CONTINUING TO RECEDE. IN ADDITION...DOPPLER RADAR INDICATES THAT ALL SIGNIFICANT RAINFALL HAS MOVED TO THE EAST OF THE SAN LORENZO BASIN AND LITTLE ADDITIONAL RAINFALL IS EXPECTED FOR THE REMAINDER OF THE EVENING. THEREFORE...THE FLASH FLOOD WARNING FOR THE SAN LORENZO RIVER IN SANTA CRUZ COUNTY HAS BEEN ALLOWED TO EXPIRE. MINOR FLOODING WILL CONTINUE ACROSS 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 3706 12213 3709 12204 3699 12201 3698 12206 $$ DYKEMA
The office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 23, 8:55 AM PST | Flash Flood Warning | MTR | Sonoma | 4 hr |
| Dec 23, 9:31 AM PST | Flash Flood Watch | MTR | Marin, Napa, Sonoma | 5 hr |
| Dec 23, 1:41 PM PST | Flash Flood Warning | MTR | Sonoma | 3 hr |
| Dec 23, 2:17 PM PST | River Flood Warning | MTR | Napa | 8 hr |
| Dec 23, 2:17 PM PST | River Flood Warning | MTR | Napa | 11 hr |
| Dec 23, 2:33 PM PST | Small Craft Advisory for Hazardous Seas | MTR | 15 hr | |
| Dec 23, 3:12 PM PST | Flash Flood Watch | MTR | Santa Cruz | 4 hr |
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.