Alert archive / California / Flash Flood Watches in 2012
Flash Flood Watch 2, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this flash flood watch at Dec 23, 2012, 9:31 AM PST for Marin County, Napa County, Sonoma County, California. It was in force for 5 hr.
The area
The counties it named.
The facts
- Issued
- Dec 23, 2012, 9:31 AM PST (17:31 UTC)
- Expired
- Dec 23, 2012, 3:00 PM PST
- In force
- 5 hr
- Issued by
- NWS San Francisco Bay Area, CA
- Flood severity
- None
Counties Marin County, CA, Napa County, CA, Sonoma County, CA
The radar
The Sacramento radar (KDAX), 88 km from the middle of the area, began a volume at 17:33 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, 5.5 hours before the alert went out and 81 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.
124 WGUS66 KMTR 231731 FFAMTR URGENT - IMMEDIATE BROADCAST REQUESTED FLOOD WATCH NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA 931 AM PST SUN DEC 23 2012 DEFAULT OVERVIEW SECTION CAZ506-232100- /O.NEW.KMTR.FF.A.0002.121223T1731Z-121223T2100Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ NORTH BAY INTERIOR VALLEYS- 931 AM PST SUN DEC 23 2012 ...FLASH FLOOD WATCH IN EFFECT UNTIL 1 PM PST THIS AFTERNOON... THE NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA HAS ISSUED A * FLASH FLOOD WATCH FOR A PORTION OF CALIFORNIA...INCLUDING THE FOLLOWING AREA...SONOMA VALLEY AND SONOMA CREEK AREA. * UNTIL 1 PM PST THIS AFTERNOON * STAGE ON SONOMA CREEK AT AGUA CALIENTE HAS REACHED NEARLY 18 FEET AS OF 8:45 PST AND THE CREEK CONTINUES TO RISE RAPIDLY IN RESPONSE TO A BAND OF INTENSE RAINFALL CURRENTLY MOVING THROUGH THE AREA. PRECAUTIONARY/PREPAREDNESS ACTIONS... A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION. YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION SHOULD FLASH FLOOD WARNINGS BE ISSUED. && $$ STRUDLEY
3 follow-up statements
329 WGUS66 KMTR 231905 FFAMTR URGENT - IMMEDIATE BROADCAST REQUESTED FLOOD WATCH NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA 1105 AM PST SUN DEC 23 2012 DEFAULT OVERVIEW SECTION CAZ506-232200- /O.EXT.KMTR.FF.A.0002.000000T0000Z-121223T2200Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ NORTH BAY INTERIOR VALLEYS- 1105 AM PST SUN DEC 23 2012 ...FLASH FLOOD WATCH NOW IN EFFECT UNTIL 2 PM PST THIS AFTERNOON... THE FLASH FLOOD WATCH IS NOW IN EFFECT FOR * A PORTION OF CALIFORNIA...INCLUDING THE FOLLOWING AREA...NORTH BAY INTERIOR VALLEYS. * UNTIL 2 PM PST THIS AFTERNOON * STAGE ON SONOMA CREEK AT AGUA CALIENTE HAS REACHED NEARLY 18 FEET AS OF 8:45 PST AND THE CREEK CONTINUES TO RISE RAPIDLY IN RESPONSE TO A BAND OF INTENSE RAINFALL CURRENTLY MOVING THROUGH THE AREA. * THE FLASH FLOOD WARNING HAS BEEN EXTENDED TO INCLUDE THE NAPA VALLEY REGION. SOME SMALL CREEKS IN THE AREA THAT FEED NAPA CREEK AND THE NAPA RIVER ARE APPROACHING MONITOR OR FLOOD STAGES. THE FRONT IS EXPECTED TO MOVE THROUGH THE AREA OVER THE NEXT SEVERAL HOURS SO CONTINUED RISE IN STAGE MAY OCCUR OVER THE NEXT SEVERAL HOURS. PRECAUTIONARY/PREPAREDNESS ACTIONS... A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION. YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION SHOULD FLASH FLOOD WARNINGS BE ISSUED. && $$ STRUDLEY
091 WGUS66 KMTR 232116 FFAMTR URGENT - IMMEDIATE BROADCAST REQUESTED FLOOD WATCH NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA 116 PM PST SUN DEC 23 2012 DEFAULT OVERVIEW SECTION CAZ505-232300- /O.EXB.KMTR.FF.A.0002.000000T0000Z-121223T2300Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ COASTAL NORTH BAY...INCLUDING POINT REYES NATIONAL SEASHORE- 116 PM PST SUN DEC 23 2012 ...FLASH FLOOD WATCH IN EFFECT UNTIL 3 PM PST THIS AFTERNOON... THE NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA HAS EXPANDED THE * FLASH FLOOD WATCH TO INCLUDE A PORTION OF CALIFORNIA... INCLUDING THE FOLLOWING AREA...SOUTHERN MARIN COUNTY. * UNTIL 3 PM PST THIS AFTERNOON * THE FLASH FLOOD WARNING HAS BEEN EXTENDED TO INCLUDE THE COASTAL WATERSHEDS OF SOUTHERN MARIN COUNTY. IN PARTICULAR, CORTE MADERA CREEK AT ROSS IS APPROACHING FLOOD STAGE AND THE FRONT HAS NOT COMPLETELY MOVED THROUGH THE AREA YET. CORTE MADERA CREEK AND OTHER ASSOCIATED DRAINAGES NEARBY MAY APPROACH OR GO ABOVE FLOOD STAGE. HOWEVER, THE FRONT IS EXPECTED TO PASS QUICKLY, SO THE DURATION AND MAGNITUDE OF FLOODING, IF IT OCCURS, SHOULD BE MINOR. PRECAUTIONARY/PREPAREDNESS ACTIONS... A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION. YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION SHOULD FLASH FLOOD WARNINGS BE ISSUED. && $$ CAZ506-232300- /O.EXT.KMTR.FF.A.0002.000000T0000Z-121223T2300Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ NORTH BAY INTERIOR VALLEYS- 116 PM PST SUN DEC 23 2012 ...FLASH FLOOD WATCH NOW IN EFFECT UNTIL 3 PM PST THIS AFTERNOON... THE FLASH FLOOD WATCH IS NOW IN EFFECT FOR * A PORTION OF CALIFORNIA...INCLUDING THE FOLLOWING AREA...NORTH BAY INTERIOR VALLEYS. * UNTIL 3 PM PST THIS AFTERNOON * STAGE ON SONOMA CREEK AT AGUA CALIENTE HAS REACHED NEARLY 18 FEET AS OF 8:45 PST AND THE CREEK CONTINUES TO RISE RAPIDLY IN RESPONSE TO A BAND OF INTENSE RAINFALL CURRENTLY MOVING THROUGH THE AREA. * THE FLASH FLOOD WARNING HAS BEEN EXTENDED TO INCLUDE THE NAPA VALLEY REGION. SOME SMALL CREEKS IN THE AREA THAT FEED NAPA CREEK AND THE NAPA RIVER ARE APPROACHING MONITOR OR FLOOD STAGES. THE FRONT IS EXPECTED TO MOVE THROUGH THE AREA OVER THE NEXT SEVERAL HOURS SO CONTINUED RISE IN STAGE MAY OCCUR OVER THE NEXT SEVERAL HOURS. PRECAUTIONARY/PREPAREDNESS ACTIONS... A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION. YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION SHOULD FLASH FLOOD WARNINGS BE ISSUED. && $$ STRUDLEY
217 WGUS66 KMTR 232312 FFAMTR URGENT - IMMEDIATE BROADCAST REQUESTED FLOOD WATCH NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA 312 PM PST SUN DEC 23 2012 DEFAULT OVERVIEW SECTION CAZ505-506-240015- /O.EXP.KMTR.FF.A.0002.000000T0000Z-121223T2300Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ COASTAL NORTH BAY...INCLUDING POINT REYES NATIONAL SEASHORE- NORTH BAY INTERIOR VALLEYS- 312 PM PST SUN DEC 23 2012 ...FLASH FLOOD WATCH HAS EXPIRED... THE FLASH FLOOD WATCH FOR A PORTION OF CALIFORNIA HAS EXPIRED. $$ CAZ529-240300- /O.NEW.KMTR.FF.A.0003.121223T2312Z-121224T0300Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ NORTHERN MONTEREY BAY- 312 PM PST SUN DEC 23 2012 ...FLASH FLOOD WATCH IN EFFECT UNTIL 7 PM PST THIS EVENING... THE NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA HAS ISSUED A * FLASH FLOOD WATCH FOR A PORTION OF CALIFORNIA...INCLUDING THE FOLLOWING AREA...LOWER SOQUEL CREEK AND APTOS CREEK SYSTEMS...INCLUDING TRIBUTARY CREEKS. * UNTIL 7 PM PST THIS EVENING * MANY LOCAL STREAM GAGES HAVE INDICATED VERY RAPID RISES IN STAGE OVER THE PAST HOUR...INCLUDING THE GAGE ON SOQUEL CREEK AT BRIDGE STREET...WHICH HAS GONE ABOVE MONITORING STAGE. MONITORING STAGE IS AT 11 AND A HALF FEET. FLOOD STAGE IS AT 14.5 FEET. ADDITIONAL RAINFALL AND RUNOFF MAY CREATE DANGEROUS CONDITIONS LOCALLY. SOME CREEKS IN THE APTOS CREEK BASIN MAY ALSO BE FLOODING..SO CAUTION IS ADVISED. PRECAUTIONARY/PREPAREDNESS ACTIONS... A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION. YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION SHOULD FLASH FLOOD WARNINGS BE ISSUED. && $$ STRUDLEY
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, 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, 2:38 PM PST | Flash Flood Warning | MTR | Santa Cruz | 5 hr |
| Dec 23, 3:12 PM PST | Flash Flood Watch | MTR | Santa Cruz | 4 hr |
Nearby
Flash Flood Watches in California, 2012Every flash flood watch 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.