Alert archive / California / High Surf Advisories in 2021
High Surf Advisory 9, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this high surf advisory at Dec 11, 2021, 1:12 PM PST for 6 counties in California. It took effect at Dec 13, 2021, 4:00 AM PST. It was in force for 54 hr.
The area
The counties it named.
The facts
- Issued
- Dec 11, 2021, 1:12 PM PST (21:12 UTC)
- In effect from
- Dec 13, 2021, 4:00 AM PST
- Expired
- Dec 15, 2021, 10:00 AM PST
- In force
- 54 hr
- Issued by
- NWS San Francisco Bay Area, CA
Counties City and County of San Francisco, CA, Marin County, CA, Monterey County, CA, San Mateo County, CA, Santa Cruz County, CA, Sonoma County, CA
The radar
The San Francisco radar (KMUX), 53 km from the middle of the area, began a volume at 21:13 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, 9.2 hours before the alert went out and 26 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1664 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- -17 m²/s²
- 0-3 km storm-relative helicity
- 53 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
895 WHUS46 KMTR 112112 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 112 PM PST Sat Dec 11 2021 CAZ006-505-509-529-530-120700- /O.NEW.KMTR.SU.Y.0009.211213T1200Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 112 PM PST Sat Dec 11 2021 ...HIGH SURF ADVISORY IN EFFECT FROM 4 AM MONDAY TO 10 AM PST WEDNESDAY... * WHAT...WNW swell of 15 to 18 feet at 15 to 17 seconds with the approaching storm system. This will result in large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal run up. * WHERE...Entire Pacific Coast from Sonoma to Monterey county. Highest risk at west to northwest facing beaches, including but not limited to: Ocean Beach, Montara State Beach, Half Moon Bay State Beach, Manresa State Beach, and Marina State Beach. * WHEN...4 AM Monday to 10 AM Wednesday. The largest waves are expected Tuesday. * IMPACTS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. * ADDITIONAL INFORMATION...Steep southerly wind waves will reduce the intensity of these waves Sunday into early Monday before dissipating. Larger waves are expected as winds and wind driven southerly seas subside later Monday into Tuesday. PRECAUTIONARY/PREPAREDNESS ACTIONS... A High Surf Advisory means that high surf will affect beaches in the advisory area, producing rip currents, localized beach erosion and sneaker waves. && $$
12 follow-up statements
041 WHUS46 KMTR 120436 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 836 PM PST Sat Dec 11 2021 CAZ006-505-509-529-530-121400- /O.CON.KMTR.SU.Y.0009.211213T1200Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 836 PM PST Sat Dec 11 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT FROM 4 AM MONDAY TO 10 AM PST WEDNESDAY... * WHAT...WNW swell of 15 to 18 feet at 15 to 17 seconds with the approaching storm system. This will result in large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal run up. * WHERE...Entire Pacific Coast from Sonoma county to Monterey county. Highest risk at west to northwest facing beaches, including but not limited to: Ocean Beach, Montara State Beach, Half Moon Bay State Beach, Manresa State Beach, and Marina State Beach. * WHEN...4 AM Monday to 10 AM Wednesday. The largest waves are expected Tuesday. * IMPACTS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. * ADDITIONAL INFORMATION...Steep southerly wind waves will reduce the intensity of these waves Sunday into early Monday before dissipating. Larger waves are expected as winds and wind driven southerly seas subside later Monday into Tuesday. PRECAUTIONARY/PREPAREDNESS ACTIONS... A High Surf Advisory means that high surf will affect beaches in the advisory area, producing rip currents, localized beach erosion and sneaker waves. && $$
819 WHUS46 KMTR 121415 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 615 AM PST Sun Dec 12 2021 CAZ006-505-509-529-530-122215- /O.CON.KMTR.SU.Y.0009.211213T1200Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 615 AM PST Sun Dec 12 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT FROM 4 AM MONDAY TO 10 AM PST WEDNESDAY... * WHAT...WNW swell of 15 to 18 feet at 15 to 17 seconds with the approaching storm system. This will result in large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal run up. * WHERE...Entire Pacific Coast from Sonoma county to Monterey county. Highest risk at west to northwest facing beaches, including but not limited to: Ocean Beach, Montara State Beach, Half Moon Bay State Beach, Manresa State Beach, and Marina State Beach. * WHEN...4 AM Monday to 10 AM Wednesday. The largest waves are expected Tuesday. * IMPACTS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. * ADDITIONAL INFORMATION...Steep southerly wind waves will reduce the intensity of these waves Sunday into early Monday before dissipating. Larger waves are expected as winds and wind driven southerly seas subside later Monday into Tuesday. PRECAUTIONARY/PREPAREDNESS ACTIONS... Inexperienced swimmers should remain out of the water due to dangerous surf conditions. && $$
663 WHUS46 KMTR 122102 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 102 PM PST Sun Dec 12 2021 CAZ006-505-509-529-530-130700- /O.CON.KMTR.SU.Y.0009.211213T1200Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 102 PM PST Sun Dec 12 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT FROM 4 AM MONDAY TO 10 AM PST WEDNESDAY... * WHAT...WNW swell of 15 to 18 feet at 15 to 17 seconds with the approaching storm system. This will result in large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal run up. * WHERE...Entire Pacific Coast from Sonoma county to Monterey county. Highest risk at west to northwest facing beaches, including but not limited to: Ocean Beach, Montara State Beach, Half Moon Bay State Beach, Manresa State Beach, and Marina State Beach. * WHEN...4 AM Monday to 10 AM Wednesday. The largest waves are expected Tuesday. * IMPACTS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. * ADDITIONAL INFORMATION...Steep southerly wind waves will reduce the intensity of these waves Sunday into early Monday before dissipating. Larger waves are expected as winds and wind driven southerly seas subside later Monday into Tuesday. PRECAUTIONARY/PREPAREDNESS ACTIONS... Inexperienced swimmers should remain out of the water due to dangerous surf conditions. && $$
672 WHUS46 KMTR 130415 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 815 PM PST Sun Dec 12 2021 CAZ006-505-509-529-530-131400- /O.CON.KMTR.SU.Y.0009.211213T1200Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 815 PM PST Sun Dec 12 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT FROM 4 AM MONDAY TO 10 AM PST WEDNESDAY... * WHAT...WNW swell of 15 to 18 feet at 15 to 17 seconds with the approaching storm system. This will result in large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal run up. * WHERE...Entire Pacific Coast from Sonoma county to Monterey county. Highest risk at west to northwest facing beaches, including but not limited to: Ocean Beach, Montara State Beach, Half Moon Bay State Beach, Manresa State Beach, and Marina State Beach. * WHEN...4 AM Monday to 10 AM Wednesday. The largest waves are expected Tuesday. * IMPACTS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. * ADDITIONAL DETAILS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. * ADDITIONAL INFORMATION...Steep southerly wind waves will reduce the intensity of these waves Sunday into early Monday before dissipating. Larger waves are expected as winds and wind driven southerly seas subside later Monday into Tuesday. PRECAUTIONARY/PREPAREDNESS ACTIONS... Inexperienced swimmers should remain out of the water due to dangerous surf conditions. && $$
413 WHUS46 KMTR 131238 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 438 AM PST Mon Dec 13 2021 CAZ006-505-509-529-530-132045- /O.CON.KMTR.SU.Y.0009.000000T0000Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 438 AM PST Mon Dec 13 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST WEDNESDAY... * WHAT...WNW swell of 15 to 18 feet at 15 to 17 seconds with the approaching storm system. This will result in large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal run up.. * WHERE...Entire Pacific Coast from Sonoma county to Monterey county. Highest risk at west to northwest facing beaches, including but not limited to: Ocean Beach, Montara State Beach, Half Moon Bay State Beach, Manresa State Beach, and Marina State Beach. * WHEN...4 AM Monday to 10 AM Wednesday. The largest waves are expected Tuesday. * IMPACTS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. * ADDITIONAL DETAILS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. * ADDITIONAL INFORMATION...Steep southerly wind waves will reduce the intensity of these waves Sunday into early Monday before dissipating. Larger waves are expected as winds and wind driven southerly seas subside later Monday into Tuesday. PRECAUTIONARY/PREPAREDNESS ACTIONS... Inexperienced swimmers should remain out of the water due to dangerous surf conditions. && $$
271 WHUS46 KMTR 131910 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 1110 AM PST Mon Dec 13 2021 CAZ006-505-509-529-530-140700- /O.CON.KMTR.SU.Y.0009.000000T0000Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 1110 AM PST Mon Dec 13 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST WEDNESDAY... * WHAT...WNW swell of 15 to 18 feet at 15 to 17 seconds with the approaching storm system. This will result in large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal run up. * WHERE...Coastal North Bay Including Point Reyes National Seashore, Southern Monterey Bay and Big Sur Coast, San Francisco Peninsula Coast, San Francisco and Northern Monterey Bay. * WHEN...Until 10 AM PST Wednesday. * IMPACTS...Dangerous swimming and surfing conditions and localized beach erosion. * ADDITIONAL DETAILS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. * ADDITIONAL INFORMATION...Steep southerly wind waves will reduce the intensity of these waves Sunday into early Monday before dissipating. Larger waves are expected as winds and wind driven southerly seas subside later Monday into Tuesday. PRECAUTIONARY/PREPAREDNESS ACTIONS... Inexperienced swimmers should remain out of the water due to dangerous surf conditions. && $$
048 WHUS46 KMTR 140359 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 759 PM PST Mon Dec 13 2021 CAZ006-505-509-529-530-141400- /O.CON.KMTR.SU.Y.0009.000000T0000Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 759 PM PST Mon Dec 13 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST WEDNESDAY... * WHAT...WNW swell of 15 to 18 feet at 15 to 17 seconds with the approaching storm system. This will result in large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal run up. * WHERE...Coastal North Bay Including Point Reyes National Seashore, Southern Monterey Bay and Big Sur Coast, San Francisco Peninsula Coast, San Francisco and Northern Monterey Bay. * WHEN...Until 10 AM PST Wednesday. * IMPACTS...Dangerous swimming and surfing conditions and localized beach erosion. * ADDITIONAL DETAILS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. * ADDITIONAL INFORMATION...Steep southerly wind waves will reduce the intensity of these waves Sunday into early Monday before dissipating. Larger waves are expected as winds and wind driven southerly seas subside later Monday into Tuesday. PRECAUTIONARY/PREPAREDNESS ACTIONS... Inexperienced swimmers should remain out of the water due to dangerous surf conditions. && $$
040 WHUS46 KMTR 141239 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 439 AM PST Tue Dec 14 2021 CAZ006-505-509-529-530-142300- /O.CON.KMTR.SU.Y.0009.000000T0000Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 439 AM PST Tue Dec 14 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST WEDNESDAY... * WHAT...WNW swell of 15 to 18 feet at 15 to 17 seconds with the approaching storm system. This will result in large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal run up. * WHERE...Coastal North Bay Including Point Reyes National Seashore, Southern Monterey Bay and Big Sur Coast, San Francisco Peninsula Coast, San Francisco and Northern Monterey Bay. * WHEN...Until 10 AM PST Wednesday. * IMPACTS...Dangerous swimming and surfing conditions and localized beach erosion. * ADDITIONAL DETAILS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. * ADDITIONAL INFORMATION...Steep southerly wind waves will reduce the intensity of these waves Sunday into early Monday before dissipating. Larger waves are expected as winds and wind driven southerly seas subside later Monday into Tuesday. PRECAUTIONARY/PREPAREDNESS ACTIONS... Inexperienced swimmers should remain out of the water due to dangerous surf conditions. && $$
137 WHUS46 KMTR 142255 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 255 PM PST Tue Dec 14 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST WEDNESDAY... CAZ006-505-509-529-530-150700- /O.CON.KMTR.SU.Y.0009.000000T0000Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 255 PM PST Tue Dec 14 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST WEDNESDAY... * WHAT...Large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal runup. * WHERE...Coastal North Bay Including Point Reyes National Seashore, Southern Monterey Bay and Big Sur Coast, San Francisco Peninsula Coast, San Francisco and Northern Monterey Bay. * WHEN...Until 10 AM PST Wednesday. * IMPACTS...Dangerous swimming and surfing conditions and localized beach erosion. * ADDITIONAL DETAILS...Breaking waves can sweep people off jetties and docks, and into cold and dangerous seas where hypothermia or drowning can occur within within a minute. PRECAUTIONARY/PREPAREDNESS ACTIONS... Inexperienced swimmers should remain out of the water due to dangerous surf conditions. && $$
045 WHUS46 KMTR 150211 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 611 PM PST Tue Dec 14 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST WEDNESDAY... CAZ006-505-509-529-530-151015- /O.CON.KMTR.SU.Y.0009.000000T0000Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 611 PM PST Tue Dec 14 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST WEDNESDAY... * WHAT...Large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal runup. * WHERE...Coastal North Bay Including Point Reyes National Seashore, Southern Monterey Bay and Big Sur Coast, San Francisco Peninsula Coast, San Francisco and Northern Monterey Bay. * WHEN...Until 10 AM PST Wednesday. * IMPACTS...Dangerous swimming and surfing conditions and localized beach erosion. PRECAUTIONARY/PREPAREDNESS ACTIONS... Inexperienced swimmers should remain out of the water due to dangerous surf conditions. && $$
621 WHUS46 KMTR 150959 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 159 AM PST Wed Dec 15 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST WEDNESDAY... CAZ006-505-509-529-530-151800- /O.CON.KMTR.SU.Y.0009.000000T0000Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 159 AM PST Wed Dec 15 2021 ...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST THIS MORNING... * WHAT...Large breaking waves of 20 to 25 feet in the surf zone as well as increased coastal runup. * WHERE...Coastal North Bay Including Point Reyes National Seashore, Southern Monterey Bay and Big Sur Coast, San Francisco Peninsula Coast, San Francisco and Northern Monterey Bay. * WHEN...Until 10 AM PST this morning. * IMPACTS...Dangerous swimming and surfing conditions and localized beach erosion. PRECAUTIONARY/PREPAREDNESS ACTIONS... Inexperienced swimmers should remain out of the water due to dangerous surf conditions. && $$
108 WHUS46 KMTR 151752 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 952 AM PST Wed Dec 15 2021 CAZ006-505-509-529-530-151900- /O.EXP.KMTR.SU.Y.0009.000000T0000Z-211215T1800Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 952 AM PST Wed Dec 15 2021 ...HIGH SURF ADVISORY WILL EXPIRE AT 10 AM PST THIS MORNING... Large northwest swells are now below 15 feet and decreasing. However seas will remain large as the next front will generate wind waves over the dissipating swell creating confused seas and potentially dangerous conditions in the near shore zone through Thursday morning. $$
The office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 11, 12:58 PM PST | Wind Advisory | MTR | Alameda, Contra Costa, Monterey, San Benito, City and County of San Francisco, San Mateo and 2 more | 51 hr |
| Dec 11, 1:29 PM PST | Gale Warning | MTR | 59 hr | |
| Dec 11, 1:29 PM PST | Small Craft Advisory | MTR | 5 days |
Nearby
High Surf Advisories in California, 2021Every high surf advisory 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.