Alert archive / California / Flash Flood Warnings in 1998

Flash Flood Warning 63, NWS San Francisco Bay Area, CA

February 19, 1998Sonoma County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Feb 19, 1998, 8:15 AM PST for Sonoma 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
Feb 19, 1998, 8:15 AM PST (16:15 UTC)
Expired
Feb 19, 1998, 2:15 PM PST
In force
6 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Whole counties

County Sonoma County, CA

The radar

The Sacramento radar (KDAX), 108 km from the middle of the area, began a volume at 16:16 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, 4.3 hours before the alert went out and 109 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 1998-02-19Temperature 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 1998-02-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 199 square meters per square second.19395878Sfc1 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
706 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
199 m²/s²
0-3 km storm-relative helicity
359 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 191620 RRA
FFWSFO
CAC097-192215-
 
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
815 AM PST THU FEB 19 1998
 
THE NATIONAL WEATHER SERVICE IN SAN FRANCISCO HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL  215 PM PST
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN NORTH CENTRAL CALIFORNIA
 
   ...SONOMA COUNTY
 
RAINFALL RATES OF .50 TO .60 AN HOUR HAVE PUSHED RIVERS...CREEKS...AND
STREAMS IN SONOMA COUNTY UP RAPIDLY. CONTINUED HEAVY RAINFALL WILL CAUSE
FLASH FLOODING ACROSS NORMALLY FLOOD PRONE AREAS OF SONOMA
COUNTY...ESPECIALLY THE PETALUMA RIVER AND WILLOW CREEK.
 
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.
 
DD/PI

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 19, 8:15 AM PSTFlash Flood WarningMTRAmador6 hr
Feb 19, 2:15 PM PSTFlash Flood WarningMTRAmador6 hr

Nearby

Flash Flood Warnings in California, 1998Every flash flood 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.