Alert archive / California / Flash Flood Warnings in 1997

Flash Flood Warning 1, NWS San Francisco Bay Area, CA

January 1, 1997San Mateo County, Santa Clara County, Santa Cruz County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Jan 1, 1997, 1:20 AM PST for San Mateo County, Santa Clara County, Santa Cruz County, California. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jan 1, 1997, 1:20 AM PST (09:20 UTC)
Expired
Jan 1, 1997, 7:30 AM PST
In force
6 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Whole counties

Counties San Mateo County, CA, Santa Clara County, CA, Santa Cruz County, CA

The radar

The San Francisco radar (KMUX), 14 km from the middle of the area, began a volume at 09:24 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, 9.3 hours before the alert went out and 58 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-pSkew-T log-p diagram, Oakland, CA at 00:00Z on 1997-01-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 89 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 00:00Z on 1997-01-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 246 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
89 J/kg
Mixed-layer CIN
-10 J/kg
Mixed-layer LCL
607 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
246 m²/s²
0-3 km storm-relative helicity
452 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.

000 
TTAA00 KSFO 010925 RRA
FFWSFO
CAC081-085-087-011530-
 
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
120 AM PST WED JAN 1 1997
 
THE NATIONAL WEATHER SERVICE IN SAN FRANCISCO HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL  730 AM PST
FOR PEOPLE IN THE FOLLOWING LOCATIONSS...
 
IN CENTRAL CALIFORNIA
 
   ...SOUTHWESTERN SAN MATEO COUNTY...WESTERN SANTA CLARA COUNTY
   ...SANTA CRUZ COUNTY
 
HEAVY RAINFALL IN THE ORDER OF A HALF AN INCH PER HOUR HAS FALLEN OVER
THE PAST TWO HOURS OVER THE SOUTHWESTERN SAN MATEO MOUNTAINS...SANTA
CRUZ MOUNTAINS...AND WESTERN SANTA CLARA MOUNTAINS. WSR88D WEATHER RADAR
SHOWS AN EVEN LARGER BAND OF HEAVY RAINFALL OFF THE CENTRAL CALIFORNIA
COAST WHICH WILL MOVE ACROSS THE WARNING AREA WITHIN THE NEXT HOUR.
 
SOME OF THE SMALL RIVERS AND CREEKS THAT WILL HAVE SHARP RISES ARE:
BUTANO...SAN GREGORIO AND PESCADERO CREEKS IN SOUTHWESTERN SAN MATEO
COUNTY...THE SAN LORENZO RIVER...SOQUEL CREEK AND CORRALITOS CREEK IN
SANTA CRUZ COUNTY. SOME OF THE TOWNS IN DANGER OF FLOODING ARE
PESCADERO...SAN GREGORIO...BOULDER CREEK...FELTON...SOQUEL...
FREEDOM...AND WATSONVILLE.
 
MUDSLIDES ARE ALSO A POSSIBILITY AS WELL AS URBANIZED FLOODING.
 
BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE
THE DANGERS OF FLOODS AND FLASH FLOODS.  IF FLASH FLOODING IS
OBSERVED...ACT QUICKLY.  MOVE UP TO ESCAPE FLOOD WATERS.  DO
NOT STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.
 
DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY.  THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO
CROSS SAFELY.  VEHICLES CAUGHT IN RISING WATER SHOULD BE
ABANDONED QUICKLY.  MOVE TO HIGHER GROUND.
 
 P
COX

The office that day

Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 1, 2:42 AM PSTFlash Flood WarningMTRNapa6 hr
Jan 1, 7:18 AM PSTFlash Flood WarningMTRAlameda, Contra Costa3 hr
Jan 1, 7:31 AM PSTFlash Flood WarningMTRSan Mateo, Santa Clara, Santa Cruz4 hr
Jan 1, 8:25 AM PSTFlash Flood WarningMTRSonoma4 hr
Jan 1, 8:25 AM PSTFlash Flood WarningMTRMarin4 hr
Jan 1, 8:25 AM PSTFlash Flood WarningMTRNapa4 hr
Jan 1, 9:00 AM PSTFlash Flood WarningMTRMonterey3 hr
Jan 1, 9:00 AM PSTFlash Flood WarningMTRAlameda, Contra Costa3 hr
Jan 1, 9:00 AM PSTFlash Flood WarningMTRSan Mateo, Santa Clara, Santa Cruz3 hr
Jan 1, 10:40 AM PSTFlash Flood WarningMTRSan Mateo, Santa Clara, Santa Cruz3 hr
Jan 1, 10:40 AM PSTFlash Flood WarningMTRAlameda, Contra Costa3 hr
Jan 1, 10:40 AM PSTFlash Flood WarningMTRMarin, Napa, Sonoma3 hr
Jan 1, 11:30 AM PSTFlash Flood WarningMTRMonterey5 hr
Jan 1, 2:15 PM PSTFlash Flood WarningMTRSan Mateo, Santa Cruz2 hr
Jan 1, 3:55 PM PSTFlash Flood WarningMTRMonterey, Santa Cruz3 hr
Jan 1, 3:55 PM PSTFlash Flood WarningMTRSan Mateo3 hr

Nearby

Flash Flood Warnings in California, 1997Every flash flood warning in 1997

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.