Alert archive / California / Flash Flood Warnings in 1998
Flash Flood Warning 45, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this flash flood warning at Feb 7, 1998, 1:25 PM PST for Napa County, Sonoma County, California. It was in force for 7 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 7, 1998, 1:25 PM PST (21:25 UTC)
- Expired
- Feb 7, 1998, 8:00 PM PST
- In force
- 7 hr
- Issued by
- NWS San Francisco Bay Area, CA
- Area
- Whole counties
Counties Napa County, CA, Sonoma County, CA
The radar
The Sacramento radar (KDAX), 83 km from the middle of the area, began a volume at 21:24 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 12:00Z, 9.4 hours before the alert went out and 95 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.
- Mixed-layer CAPE
- 139 J/kg
- Mixed-layer CIN
- -4 J/kg
- Mixed-layer LCL
- 532 m above ground
- 0-6 km bulk shear
- 54 kt
- 0-1 km storm-relative helicity
- 174 m²/s²
- 0-3 km storm-relative helicity
- 268 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KSFO 072126 FFWSFO CAC041-097-055-080400- BULLETIN - EAS ACTIVATION REQUESTED FLASH FLOOD WARNING NATIONAL WEATHER SERVICE SAN FRANCISCO CA 125 PM PST SAT FEB 7 1998 ...THE NATIONAL WEATHER SERVICE IN SAN FRANCISCO HAS EXTENDED THE FLASH FLOOD WARNING FOR SONOMA...MARIN AND NAPA COUNTIES UNTIL 8 PM THIS EVENING... THE FLASH FLOOD WARNING FOR SONOMA...MARIN AND NAPA COUNTIES HAS BEEN EXTENDED UNTIL 8 PM THIS EVENING. VERY HEAVY RAIN THIS MORNING AND EARLY AFTERNOON HAS CAUSED WIDESPREAD FLOODING IN THE WARNING AREA. THE PETALUMA RIVER IN SONOMA COUNTY IS FLOODING AND IS EXPECTED TO CONTINUE WELL OUT OF ITS BANKS INTO EARLY EVENING. SEVERAL ROADS IN THE AREA ARE UNDER WATER AND CLOSED TO TRAFFIC. THERE HAVE BEEN SEVERAL REPORTS OF MUDSLIDES IN THE WARNING AREA. ALTHOUGH RAINFALL RATES HAVE DROPPED OFF QUICKLY IN THE PAST HOUR...HEAVY RUNOFF WILL CONTINUE AND SMALL RIVERS AND STREAMS WILL CONTINUE OUT OF THEIR BANKS FOR THE NEXT SEVERAL HOURS. BRIEF HEAVY RAIN IS POSSIBLE THROUGH EARLY THIS EVENING IN SHOWERS AND THUNDERSTORMS. THE POSSIBILITY OF MUDSLIDES WILL CONTINUE WELL AFTER THE RAINFALL HAS ENDED. 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. DYKEMA
The office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 6, 9:15 PM PST | Flash Flood Warning | MTR | San Mateo | 3 hr |
| Feb 6, 9:15 PM PST | Flash Flood Warning | MTR | Sonoma | 3 hr |
| Feb 7, 8:30 AM PST | Flash Flood Warning | MTR | Amador | 6 hr |
| Feb 7, 8:30 AM PST | Flash Flood Warning | MTR | Riverside | 6 hr |
| Feb 7, 12:05 PM PST | Flash Flood Warning | MTR | Alameda, San Mateo, Santa Clara, Santa Cruz | 8 hr |
| Feb 7, 12:05 PM PST | Flash Flood Warning | MTR | Contra Costa | 8 hr |
| Feb 7, 12:05 PM PST | Flash Flood Warning | MTR | City and County of San Francisco | 8 hr |
| Feb 7, 12:24 PM PST | Flash Flood Warning | MTR | Monterey, San Benito | 8 hr |
| Feb 7, 1:25 PM PST | Flash Flood Warning | MTR | Marin | 7 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.