Alert archive / California / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 1, NWS San Francisco Bay Area, CA

February 6, 1998Santa Clara County, Santa Cruz County, California

NWS San Francisco Bay Area, CA issued this severe thunderstorm warning at Feb 6, 1998, 2:02 PM PST for Santa Clara County, Santa Cruz County, California. It was in force for 58 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Feb 6, 1998, 2:02 PM PST (22:02 UTC)
Expired
Feb 6, 1998, 3:00 PM PST
In force
58 min
Issued by
NWS San Francisco Bay Area, CA
Area
Whole counties

Counties Santa Clara County, CA, Santa Cruz County, CA

The radar

The San Francisco radar (KMUX), 5 km from the middle of the area, began a volume at 22:04 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Feb 6, 11:45 AM PSTSevere Thunderstorm WatchSPC4 hr

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 10.0 hours before the alert went out and 74 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 1998-02-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 1998-02-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 210 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1526 m above ground
0-6 km bulk shear
67 kt
0-1 km storm-relative helicity
210 m²/s²
0-3 km storm-relative helicity
448 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.

211 
WUUS1 KSFO 062209 RRA
SVRSFO
CAC085-087-062300-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
202 PM PST FRI FEB 6 1998
 
THE NATIONAL WEATHER SERVICE IN SAN FRANCISCO HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  300 PM PST
FOR PEOPLE IN THE FOLLOWING LOCATIONSS...
 
IN CENTRAL CALIFORNIA
 
   ...SOUTHWESTERN SANTA CLARA COUNTY
   ...EASTERN SANTA CRUZ COUNTY
 
 
WSR88D AND SPOTTERS REPORT A SEVERE THUNDERSTORM WITH DIME SIZE HAIL
OVER SANTA CRUZ AT 2PM. THIS STORM CELL IS MOVING NOTHEAST AT 30 MILES
PER HOUR. THIS STORM WILL MOVE INTO SANTA CLARA COUNTY JUST NORTH OF
MORGAN HILL BY 230PM. HEAVY RAIN...STRONG GUSTY WINDS AND LARGE HAIL
WILL ACCOMPANY THIS STORM. TAKE COVER.
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN.
FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR
OF YOUR HOME OR BUSINESS.  HEAVY RAINS FLOOD ROADS QUICKLY SO
DONT DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.
 
 
 
COX/CARROLL/CANEPA

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 5, 4:00 PM PSTFlash Flood WarningMTRNapa, Sonoma8 hr
Feb 5, 4:00 PM PSTFlash Flood WarningMTRMarin8 hr
Feb 6, 8:42 AM PSTFlash Flood WarningMTRMonterey6 hr
Feb 6, 9:38 AM PSTFlash Flood WarningMTRSan Mateo, Santa Clara5 hr
Feb 6, 11:45 AM PSTFlash Flood WarningMTRMarin, Sonoma3 hr
Feb 6, 2:44 PM PSTFlash Flood WarningMTRSonoma3 hr
Feb 6, 2:44 PM PSTFlash Flood WarningMTRSan Mateo3 hr

Nearby

Severe Thunderstorm Warnings in California, 1998Every severe thunderstorm warning in 1998

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.