Alert archive / California / Flash Flood Warnings in 1997

Flash Flood Warning 23, NWS San Francisco Bay Area, CA

January 2, 1997San Mateo County, Santa Clara County, Santa Cruz County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Jan 2, 1997, 5:52 AM PST for San Mateo County, Santa Clara County, Santa Cruz County, California. It was in force for 3 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 2, 1997, 5:52 AM PST (13:52 UTC)
Expired
Jan 2, 1997, 9:00 AM PST
In force
3 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 13:55 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, 1.9 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 12:00Z on 1997-01-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 12:00Z on 1997-01-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 148 square meters per square second.1939587897117Sfc1 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
2 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
474 m above ground
0-6 km bulk shear
79 kt
0-1 km storm-relative helicity
148 m²/s²
0-3 km storm-relative helicity
268 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 021355
FFWSFO
CAC001-013-081-085-087-021700-
 
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
552 AM PST THU JAN 2 1997
 
THE NATIONAL WEATHER SERVICE IN SAN FRANCISCO HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL  900 AM PST
FOR PEOPLE IN THE FOLLOWING LOCATIONSS...
 
IN CENTRAL CALIFORNIA
 
   ...ALAMEDA COUNTY...CONTRA COSTA COUNTY...SAN MATEO COUNTY
   ...SANTA CLARA COUNTY...SANTA CRUZ COUNTY
 
RADAR AND PAST HOUR RAINFALL RATES INDICATE THAT ANOTHER BAND OF
MODERATE TO HEAVY RAIN IS MAKING ITS WAY OVER THE PENNINSULA...EAST
BAY...SANTA CRUZ AND SANTA CLARA COUNTIES WITH RAINFALL RATES OF A THIRD
TO ONE HALF AND INCH AN HOUR. URBAN FLOODING CAN BE EXPECTED OVER THE
NEXT THREE HOURS AND MUDSLIDES ARE ALSO POSSIBLE. THE SMALLER RIVERS AND
STREAMS IN THE WARNING AREA WILL CONTINUE TO RISE OVER THE NEXT THREE
HOURS.
 
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.
 
A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT.  MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES.  DO NOT
ATTEMPT TO CROSS BRIDGES...DIPS...OR LOW SPOTS IF WATER COVERS
THE ROADWAY.  NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL
ONE...ON FOOT.  TO ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.
 
DIAZ/COX

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 1, 5:03 PM PSTFlash Flood WarningMTRSanta Clara117 min
Jan 1, 7:00 PM PSTFlash Flood WarningMTRSan Mateo, Santa Clara, Santa Cruz4 hr
Jan 1, 7:22 PM PSTFlash Flood WarningMTRSan Luis Obispo6 hr
Jan 1, 10:59 PM PSTFlash Flood WarningMTRSan Mateo, Santa Clara, Santa Cruz3 hr
Jan 2, 5:52 AM PSTFlash Flood WarningMTRAlameda, Contra Costa3 hr
Jan 2, 11:45 AM PSTFlash Flood WarningMTRAlameda, San Mateo, Santa Clara, Santa Cruz4 hr
Jan 2, 11:45 AM PSTFlash Flood WarningMTRMonterey4 hr
Jan 2, 11:45 AM PSTFlash Flood WarningMTRContra Costa4 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.