Alert archive / California / Flash Flood Warnings in 1997

Flash Flood Warning 4, 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, 7:31 AM PST for San Mateo County, Santa Clara County, Santa Cruz County, California. It was in force for 4 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, 7:31 AM PST (15:31 UTC)
Expired
Jan 1, 1997, 11:30 AM PST
In force
4 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 15:32 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, 3.5 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 1997-01-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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 12:00Z on 1997-01-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 359 square meters per square second.1939587897Sfc1 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
1 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
503 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
359 m²/s²
0-3 km storm-relative helicity
515 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KSFO 011535
FFWSFO
CAC081-085-087-011930-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
731 AM PST WED JAN 1 1997
 
THE NATIONAL WEATHER SERVICE IN SAN FRANCISCO HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL 1130 AM PST
FOR PEOPLE IN THE FOLLOWING LOCATIONSS...
 
IN CENTRAL CALIFORNIA
 
   ...SOUTHWESTERN SAN MATEO COUNTY...WESTERN SANTA CLARA COUNTY
   ...SANTA CRUZ COUNTY
 
HEAVY RAIN HAS MOVED OVER THE SANTA CRUZ AND SAN MATEO COSTAL MOUNTAINS
AND RADAR SHOWS ADDITIONAL AREAS OF MODERATE TO HEAVY RAIN THAT WILL
MOVE OVER THE AREA FOR THE NEXT SEVERAL HOURS. RAINFALL AMOUNTS OF .3 TO
.5 INCHES AND HOUR HAVE OCCURED OVER THE PAST HOUR AND EXPECTED TO LAST
FOR THE NEXT FOUR HOURS.
 
SAN LORENZO IS CURRENTLY AT 13.2 FEET AND IS LESS THAN A FOOT OF BEING
BANKFULL.  SOME TOWNS THAT WILL BE EFFECTED ARE :  BOULDER
CREEK...FELTON...AND BEN LOMAND.
 
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 IMMINENT.  IT'S
IMPORTANT TO KNOW WHERE YOU ARE RELATIVE TO STREAMS...RIVERS...OR
CREEKS WHICH CAN BECOME KILLERS IN HEAVY RAINS.  CAMPERS SHOULD
AVOID CAMPING ALONG STREAMS OR CREEKS DURING THREATENING RAINS.
 
 
DIAZ/COX

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 1, 1:20 AM PSTFlash Flood WarningMTRSan Mateo, Santa Clara, Santa Cruz6 hr
Jan 1, 2:42 AM PSTFlash Flood WarningMTRNapa6 hr
Jan 1, 7:18 AM PSTFlash Flood WarningMTRAlameda, Contra Costa3 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.