Alert archive / California / Flash Flood Warnings in 2021
Flash Flood Warning 1, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this flash flood warning at Jan 26, 2021, 9:39 PM PST for Sonoma County, California. It was in force for 81 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Jan 26, 2021, 9:39 PM PST (05:39 UTC)
- Expired
- Jan 26, 2021, 11:00 PM PST
- In force
- 81 min
- Issued by
- NWS San Francisco Bay Area, CA
- Area
- Storm-based polygon
- Damage threat
- Considerable
- Flood severity
- None
County Sonoma County, CA
The radar
The Sacramento radar (KDAX), 117 km from the middle of the area, began a volume at 05:40 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 00:00Z, 5.7 hours before the alert went out and 122 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
- 1 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 863 m above ground
- 0-6 km bulk shear
- 49 kt
- 0-1 km storm-relative helicity
- 118 m²/s²
- 0-3 km storm-relative helicity
- 329 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
723
WGUS56 KMTR 270539
FFWMTR
CAC097-270700-
/O.NEW.KMTR.FF.W.0001.210127T0539Z-210127T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
939 PM PST Tue Jan 26 2021
The National Weather Service in San Francisco has issued a
* Flash Flood Warning for...
The Walbridge portion of the LNU Lightning Complex burn area in...
North Central Sonoma County in northern California...
* Until 1100 PM PST.
* At 939 PM PST, Doppler radar and automated rain gauges indicated
heavy rain falling over the Walbridge portion of the LNU Lightning
Complex Burn Area. Between 1.5 and 2.5 inches of rain have fallen.
Rain rates could increase within the next half hour. Flash
flooding is expected to begin shortly.
Excessive rainfall over the burn area will result in debris flow
moving through the Walbridge portion of the LNU Lightning Complex
burn area. The debris flow can consist of rock, mud, vegetation and
other loose materials.
HAZARD...Life threatening flash flooding. Heavy rain producing
flash flooding in and around the Walbridge portion of
the LNU Lightning Complex Burn Area.
SOURCE...Doppler radar and automated gauges.
IMPACT...Life threatening flash flooding of areas in and around
the Walbridge portion of the LNU Lightning Complex
Burn Area.
* Some locations that will experience flash flooding include...
mainly rural areas of North Central Sonoma County
This is a life threatening situation for people in or near the
Walbridge Fire burn area. Some drainage basins impacted include...
Miller Creek and Redwood Log Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Move away from recently burned areas. Life-threatening flooding of
creeks, roads and normally dry arroyos is likely. The heavy rains
will likely trigger rockslides, mudslides and debris flows in steep
terrain, especially in and around these areas.
This is a life-threatening situation. If you observe movement of
soils move to higher ground immediately.
&&
LAT...LON 3859 12306 3860 12310 3866 12312 3867 12309
3868 12310 3869 12308 3871 12308 3869 12300
3865 12296 3865 12297 3864 12294 3860 12291
3859 12294 3857 12289 3853 12295 3854 12298
3855 12297 3854 12303
FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR AND 30 MINUTES
$$
MTR2 follow-up statements
812
WGUS76 KMTR 270631
FFSMTR
Flash Flood Statement
National Weather Service San Francisco CA
1031 PM PST Tue Jan 26 2021
CAC097-270700-
/O.CON.KMTR.FF.W.0001.000000T0000Z-210127T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sonoma CA-
1031 PM PST Tue Jan 26 2021
...FLASH FLOOD WARNING FOR THE WALBRIDGE PORTION OF THE LNU
LIGHTNING COMPLEX BURN AREA REMAINS IN EFFECT UNTIL 11 PM PST THIS
EVENING FOR NORTH CENTRAL SONOMA COUNTY...
At 1031 PM PST, Doppler radar and automated rain gauges indicated
that the narrow band of heavy rain falling over the Walbridge
portion of the LNU Lightning Complex Burn Area is moving quickly
eastward. Rain rates are expected to drop significantly within the
next half hour once that narrow band exits the region.
Excessive rainfall over the burn area will result in debris flow
moving through the Walbridge portion of the LNU Lightning Complex
burn area. The debris flow can consist of rock, mud, vegetation and
other loose materials.
HAZARD...Life threatening flash flooding. Heavy rain producing
flash flooding in and around the Walbridge portion of
the LNU Lightning Complex Burn Area.
SOURCE...Doppler radar and automated gauges.
IMPACT...Life threatening flash flooding of areas in and around
the Walbridge portion of the LNU Lightning Complex Burn
Area.
Some locations that will experience flash flooding include...
mainly rural areas of North Central Sonoma County
This is a life threatening situation for people in or near the
Walbridge Fire burn area. Some drainage basins impacted include...
Miller Creek and Redwood Log Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Move away from recently burned areas. Life-threatening flooding of
creeks, roads and normally dry arroyos is likely. The heavy rains
will likely trigger rockslides, mudslides and debris flows in steep
terrain, especially in and around these areas.
This is a life-threatening situation. If you observe movement of
soils move to higher ground immediately.
&&
LAT...LON 3859 12306 3860 12310 3866 12312 3867 12309
3868 12310 3869 12308 3871 12308 3869 12300
3865 12296 3865 12297 3864 12294 3860 12291
3859 12294 3857 12289 3853 12295 3854 12298
3855 12297 3854 12303
FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR AND 30 MINUTES
$$
MTR312
WGUS76 KMTR 270655
FFSMTR
Flash Flood Statement
National Weather Service San Francisco CA
1055 PM PST Tue Jan 26 2021
CAC097-270705-
/O.EXP.KMTR.FF.W.0001.000000T0000Z-210127T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sonoma CA-
1055 PM PST Tue Jan 26 2021
...FLASH FLOOD WARNING FOR THE WALBRIDGE PORTION OF THE LNU
LIGHTNING COMPLEX BURN AREA WILL EXPIRE AT 11 PM PST THIS EVENING
FOR NORTH CENTRAL SONOMA COUNTY...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
A Flash Flood Watch remains in effect until 400 PM PST Thursday for
a portion of western California.
LAT...LON 3859 12306 3860 12310 3866 12312 3867 12309
3868 12310 3869 12308 3871 12308 3869 12300
3865 12296 3865 12297 3864 12294 3860 12291
3859 12294 3857 12289 3853 12295 3854 12298
3855 12297 3854 12303
$$
BBThe office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jan 26, 10:22 PM PST | Areal Flood Advisory | MTR | Marin, Napa, Sonoma | 4 hr |
| Jan 26, 10:56 PM PST | Flash Flood Warning | MTR | San Mateo, Santa Cruz | 4 hr |
| Jan 26, 11:18 PM PST | Areal Flood Advisory | MTR | Alameda, City and County of San Francisco, San Mateo, Santa Clara | 4 hr |
| Jan 26, 11:46 PM PST | Special Marine Warning | MTR | 14 min | |
| Jan 27, 1:31 AM PST | Flash Flood Warning | MTR | Monterey | 3 hr |
| Jan 27, 1:38 AM PST | Flash Flood Warning | MTR | Monterey | 14 hr |
| Jan 27, 1:45 AM PST | Flash Flood Warning | MTR | Monterey | 3 hr |
| Jan 27, 2:06 AM PST | Special Marine Warning | MTR | 24 min | |
| Jan 27, 2:18 AM PST | Areal Flood Advisory | MTR | Monterey, Santa Cruz | 117 min |
| Jan 27, 2:23 AM PST | Gale Warning | MTR | 3 hr | |
| Jan 27, 2:23 AM PST | Small Craft Advisory | MTR | 55 hr | |
| Jan 27, 5:27 AM PST | Gale Warning | MTR | 21 hr | |
| Jan 27, 12:03 PM PST | Flash Flood Warning | MTR | Monterey | 3 hr |
| Jan 27, 12:05 PM PST | Flash Flood Warning | MTR | Monterey | 3 hr |
| Jan 27, 12:33 PM PST | Flash Flood Warning | MTR | San Mateo, Santa Cruz | 6 hr |
| Jan 27, 12:53 PM PST | Special Marine Warning | MTR | 52 min | |
| Jan 27, 2:11 PM PST | Areal Flood Advisory | MTR | Alameda, Monterey, San Benito, San Mateo, Santa Clara, Santa Cruz | 5 hr |
Nearby
Flash Flood Warnings in California, 2021Every flash flood warning in 2021
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.