Alert archive / California / Beach Hazards Statements in 2020
Beach Hazards Statement 15, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this beach hazards statement at Dec 14, 2020, 7:21 PM PST for 6 counties in California. It took effect at Dec 15, 2020, 3:00 PM PST. It was in force for 12 hr.
The area
The counties it named.
The facts
- Issued
- Dec 14, 2020, 7:21 PM PST (03:21 UTC)
- In effect from
- Dec 15, 2020, 3:00 PM PST
- Expired
- Dec 16, 2020, 3:00 AM PST
- In force
- 12 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 03:21 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, 3.4 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
- 1430 m above ground
- 0-6 km bulk shear
- 59 kt
- 0-1 km storm-relative helicity
- -53 m²/s²
- 0-3 km storm-relative helicity
- -11 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
360 WHUS46 KMTR 150321 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 721 PM PST Mon Dec 14 2020 ...KING TIDES WILL CAUSE MINOR COASTAL OVERFLOW AND FLOODING THROUGH TUESDAY... ...LARGE, LONG PERIOD NORTHWEST SWELL WILL BRING HAZARDOUS CONDITIONS ALONG THE COAST LATE TUESDAY THROUGH WEDNESDAY... King Tides will continue to impact the region through tomorrow leading to the intrusion of seawater into low lying areas, generating minor coastal flooding. The main time period of concern will occur during the highest of the high tides Tuesday morning. Additionally, another long period northwest swell will arrive along the coast by Tuesday afternoon. Forerunner waves of 3 to 7 feet at 19 to 22 seconds are expected initially resulting in a brief moderate threat of sneaker waves, particularly during the low tide. This swell will quickly build overnight and into Wednesday generating large breaking waves of 15 to 20 feet, locally up to 25 feet at favored breakpoints. High tides will still be on the larger side Wednesday morning as the King Tides only just begin to subside creating an additional danger. Thus, the surf zone/area beaches will remain hazardous into Wednesday afternoon. CAZ006-505-509-529-530-151500- /O.EXP.KMTR.SU.Y.0007.000000T0000Z-201215T0300Z/ /O.NEW.KMTR.SU.Y.0008.201216T1200Z-201217T0000Z/ /O.NEW.KMTR.BH.S.0015.201216T0000Z-201216T1200Z/ /O.CON.KMTR.CF.Y.0002.000000T0000Z-201215T2100Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 721 PM PST Mon Dec 14 2020 ...COASTAL FLOOD ADVISORY REMAINS IN EFFECT UNTIL 1 PM PST TUESDAY... ...BEACH HAZARDS STATEMENT IN EFFECT FROM TUESDAY AFTERNOON THROUGH LATE TUESDAY NIGHT... ...HIGH SURF ADVISORY IN EFFECT FROM 4 AM TO 4 PM PST WEDNESDAY... * WHAT...For the Coastal Flood Advisory, minor coastal flooding expected. High tides expected in the mid to late morning with low tides in the late afternoon to early evening. The High Tide at San Francisco will meet or exceed 7 feet. For the Beach Hazards Statement, infrequent yet dangerous sneaker waves are expected tomorrow afternoon and evening. For the High Surf Advisory, large breaking waves of 15 to 20 feet expected at west to northwest facing beaches, locally up to 25 feet at favored breakpoints. * WHERE...San Francisco, Coastal North Bay Including Point Reyes National Seashore, San Francisco Peninsula Coast and Southern Monterey Bay and Big Sur Coast Counties, particularly at West and Northwest facing beaches. * WHEN...For the Coastal Flood Advisory, until 1 PM PST Tuesday. For the Beach Hazards Statement, from Tuesday afternoon through late Tuesday night. For the High Surf Advisory, from 4 AM to 4 PM PST Wednesday. * IMPACTS...Flooding of lots, parks, and roads with only isolated road closures expected. Sneaker waves and large breaking waves can sweep people off jetties and docks, and into dangerous seas. Cold water rescues or drownings are more likely with these waves and stronger rip currents. Dangerous swimming and surfing conditions and localized beach erosion. PRECAUTIONARY/PREPAREDNESS ACTIONS... If travel is required, allow extra time as some roads may be closed. Do not drive around barricades or through water of unknown depth. Take the necessary actions to protect flood-prone property. Conditions are present to support a heightened risk of unsuspecting beach goers being swept into the sea by a wave. People walking along the beach should never turn their back to the sea. Fisherman should avoid fishing from rocks or jetties. Large breaking waves along the coast will lead to increased wave run-up on beaches with waves topping and washing over large rocks and jetties. Remain out of the water to avoid hazardous swimming conditions. && $$ CAZ506-151500- /O.CON.KMTR.CF.Y.0002.000000T0000Z-201215T2100Z/ North Bay Interior Valleys- 721 PM PST Mon Dec 14 2020 ...COASTAL FLOOD ADVISORY REMAINS IN EFFECT UNTIL 1 PM PST TUESDAY... * WHAT...Minor coastal flooding expected. High tides expected in the mid to late morning with low tides in the late afternoon to early evening. * WHERE...North Bay Shorelines. * WHEN...Until 1 PM PST Tuesday. * IMPACTS...Flooding of lots, parks, and roads with only isolated road closures expected. PRECAUTIONARY/PREPAREDNESS ACTIONS... If travel is required, allow extra time as some roads may be closed. Do not drive around barricades or through water of unknown depth. Take the necessary actions to protect flood-prone property. && $$
5 follow-up statements
152 WHUS46 KMTR 151236 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 436 AM PST Tue Dec 15 2020 ...KING TIDES WILL CAUSE MINOR COASTAL OVERFLOW AND FLOODING THROUGH TUESDAY... ...LARGE LONG PERIOD NORTHWEST SWELL WILL BRING HAZARDOUS CONDITIONS ALONG THE COAST LATE TUESDAY THROUGH WEDNESDAY... King Tides will continue in the region today. However, northerly winds along the coast are creating an upwelling type scenario which causes tides to typically come in under prediction. The SF tidal station is forecast to reach 6.998 feet just after 11 am, but will likely be more in the 6.7 to 6.8 range when projecting the current negative anomaly forward. This will limit impacts along the Embarcadero, Bayside Marin, and other typically impacted areas. The coastal flood advisory will remain in place as a precautionary measure. Another long period northwest swell will arrive along the coast this afternoon. Forerunner waves of 3 to 7 feet at 19 to 22 seconds are expected initially resulting in a brief moderate threat of sneaker waves, particularly during the low tide. This swell will quickly build overnight and into Wednesday generating large breaking waves of 15 to 20 feet, locally up to 25 feet at favored breakpoints. High tides will still be on the full side Wednesday morning as the King Tides only just begin to subside creating an additional danger. Thus, the surf zone/area beaches will remain hazardous into Wednesday afternoon. CAZ006-505-509-529-530-152045- /O.EXT.KMTR.SU.Y.0008.201216T1100Z-201216T2300Z/ /O.EXT.KMTR.BH.S.0015.201215T2300Z-201216T1100Z/ /O.CON.KMTR.CF.Y.0002.000000T0000Z-201215T2100Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 436 AM PST Tue Dec 15 2020 ...COASTAL FLOOD ADVISORY REMAINS IN EFFECT UNTIL 1 PM PST THIS AFTERNOON... ...BEACH HAZARDS STATEMENT NOW IN EFFECT FROM 3 PM PST THIS AFTERNOON THROUGH LATE TONIGHT... ...HIGH SURF ADVISORY NOW IN EFFECT FROM 3 AM TO 3 PM PST WEDNESDAY... * WHAT...For the Coastal Flood Advisory, minor coastal flooding expected. High tides are forecast for late morning. The High Tide at San Francisco will be near 7 feet. For the Beach Hazards Statement, infrequent yet dangerous sneaker waves are expected this afternoon and evening. For the High Surf Advisory on Wednesday, large breaking waves of 15 to 20 feet expected at west to northwest facing beaches, locally up to 25 feet at favored breakpoints. * WHERE...San Francisco, Coastal North Bay Including Point Reyes National Seashore, San Francisco Peninsula Coast and Southern Monterey Bay and Big Sur Coast Counties, particularly at West and Northwest facing beaches. * WHEN...For the Coastal Flood Advisory, until 1 PM PST this afternoon. For the Beach Hazards Statement, from 3 PM PST this afternoon through late tonight. For the High Surf Advisory, from 3 AM to 3 PM PST Wednesday. * IMPACTS...Flooding of lots, parks, and roads with only isolated road closures expected. Sneaker waves and large breaking waves can sweep people off jetties and docks, and into dangerous seas. Cold water rescues or drownings are more likely with these waves and stronger rip currents. Dangerous swimming and surfing conditions and localized beach erosion. PRECAUTIONARY/PREPAREDNESS ACTIONS... If travel is required, allow extra time as some roads may be closed. Do not drive around barricades or through water of unknown depth. Take the necessary actions to protect flood-prone property. Conditions are present to support a heightened risk of unsuspecting beach goers being swept into the sea by a wave. People walking along the beach should never turn their back to the sea. Fisherman should avoid fishing from rocks or jetties. Large breaking waves along the coast will lead to increased wave run-up on beaches with waves topping and washing over large rocks and jetties. Remain out of the water to avoid hazardous swimming conditions. && $$ CAZ506-152045- /O.CON.KMTR.CF.Y.0002.000000T0000Z-201215T2100Z/ North Bay Interior Valleys- 436 AM PST Tue Dec 15 2020 ...COASTAL FLOOD ADVISORY REMAINS IN EFFECT UNTIL 1 PM PST THIS AFTERNOON... * WHAT...Minor coastal flooding expected. High tides expected late morning. * WHERE...North Bay Shorelines. * WHEN...Until 1 PM PST Tuesday. * IMPACTS...Flooding of lots, parks, and roads with only isolated road closures expected. PRECAUTIONARY/PREPAREDNESS ACTIONS... If travel is required, allow extra time as some roads may be closed. Do not drive around barricades or through water of unknown depth. Take the necessary actions to protect flood-prone property. && $$
713 WHUS46 KMTR 152052 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 1252 PM PST Tue Dec 15 2020 ...LARGE LONG PERIOD NORTHWEST SWELL WILL BRING HAZARDOUS CONDITIONS ALONG THE COAST LATE TUESDAY THROUGH WEDNESDAY... .Another long period northwest swell will arrive along the coast this afternoon. Forerunner waves of 3 to 7 feet at 19 to 22 seconds are expected initially resulting in a brief moderate threat of sneaker waves, particularly during the low tide. This swell will quickly build overnight and into Wednesday generating large breaking waves of 15 to 20 feet, locally up to 25 feet at favored breakpoints. High tides will still be on the full side Wednesday morning as the King Tides only just begin to subside creating an additional danger. Thus, the surf zone and area beaches will remain hazardous into Wednesday afternoon. CAZ006-505-509-529-530-152300- /O.EXP.KMTR.CF.Y.0002.000000T0000Z-201215T2100Z/ /O.CON.KMTR.SU.Y.0008.201216T1100Z-201216T2300Z/ /O.CON.KMTR.BH.S.0015.201215T2300Z-201216T1100Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 1252 PM PST Tue Dec 15 2020 ...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH LATE TONIGHT... ...HIGH SURF ADVISORY REMAINS IN EFFECT FROM 3 AM TO 3 PM PST WEDNESDAY... * WHAT...For the High Surf Advisory, large breaking waves of 15 to 20 feet at west to northwest facing beaches, locally up to 25 feet at favored breakpoints. For the Beach Hazards Statement infrequent yet dangerous sneaker waves are expected this afternoon and evening. * WHERE...San Francisco, Coastal North Bay Including Point Reyes National Seashore, San Francisco Peninsula Coast and Southern Monterey Bay and Big Sur Coast Counties, particularly at West and Northwest facing beaches. * WHEN...For the Beach Hazards Statement, from 3 PM PST this afternoon through late tonight. For the High Surf Advisory, from 3 AM to 3 PM PST Wednesday. * IMPACTS...Sneaker waves and large breaking waves can sweep people off jetties and docks, and into dangerous seas. Cold water rescues or drownings are more likely with these waves and stronger rip currents. 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. Remain out of the water to avoid hazardous swimming conditions. && $$ CAZ506-152200- /O.EXP.KMTR.CF.Y.0002.000000T0000Z-201215T2100Z/ North Bay Interior Valleys- 1252 PM PST Tue Dec 15 2020 ...COASTAL FLOOD ADVISORY WILL EXPIRE AT 1 PM PST THIS AFTERNOON... The highest tides have occurred with negative low tides for the next cycle. Even though tides will be higher than normal on Wednesday the coastal flood advisory will be allowed to expire at 1 pm Tuesday. $$
509 WHUS46 KMTR 152236 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 236 PM PST Tue Dec 15 2020 ...LARGE LONG PERIOD NORTHWEST SWELL WILL BRING HAZARDOUS CONDITIONS ALONG THE COAST LATE TUESDAY THROUGH WEDNESDAY... .Another long period northwest swell will arrive along the coast this afternoon. Forerunner waves of 3 to 7 feet at 19 to 22 seconds are expected initially resulting in a brief moderate threat of sneaker waves, particularly during the low tide. This swell will quickly build overnight and into Wednesday generating large breaking waves of 15 to 20 feet, locally up to 25 feet at favored breakpoints. High tides will still be on the full side Wednesday morning as the King Tides only just begin to subside creating an additional danger. Thus, the surf zone and area beaches will remain hazardous into Wednesday afternoon. CAZ006-505-509-529-530-160630- /O.CON.KMTR.SU.Y.0008.201216T1100Z-201216T2300Z/ /O.CON.KMTR.BH.S.0015.201215T2300Z-201216T1100Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 236 PM PST Tue Dec 15 2020 ...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH LATE TONIGHT... ...HIGH SURF ADVISORY REMAINS IN EFFECT FROM 3 AM TO 3 PM PST WEDNESDAY... * WHAT...For the High Surf Advisory, large breaking waves of 15 to 20 feet at west to northwest facing beaches, locally up to 25 feet at favored breakpoints. For the Beach Hazards Statement infrequent yet dangerous sneaker waves are expected this afternoon and evening. * WHERE...San Francisco, Coastal North Bay Including Point Reyes National Seashore, San Francisco Peninsula Coast and Southern Monterey Bay and Big Sur Coast Counties, particularly at West and Northwest facing beaches. * WHEN...For the Beach Hazards Statement, from 3 PM PST this afternoon through late tonight. For the High Surf Advisory, from 3 AM to 3 PM PST Wednesday. * IMPACTS...Sneaker waves and large breaking waves can sweep people off jetties and docks, and into dangerous seas. Cold water rescues or drownings are more likely with these waves and stronger rip currents. 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. Remain out of the water to avoid hazardous swimming conditions. && $$
247 WHUS46 KMTR 160538 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 938 PM PST Tue Dec 15 2020 ...LARGE LONG PERIOD NORTHWEST SWELL WILL BRING HAZARDOUS CONDITIONS ALONG THE COAST THROUGH WEDNESDAY... .Another long period northwest swell will impact the coastline through Wednesday. Forerunner waves of 3 to 7 feet at 19 to 22 seconds are expected initially resulting in a brief moderate threat of sneaker waves. This swell will quickly build overnight and into Wednesday generating large breaking waves of 15 to 20 feet, locally up to 25 feet at favored breakpoints. High tides will still be on the full side Wednesday morning as the King Tides only just begin to subside creating an additional danger. Thus, the surf zone and area beaches will remain hazardous into Wednesday afternoon. CAZ006-505-509-529-530-161100- /O.CON.KMTR.SU.Y.0008.201216T1100Z-201216T2300Z/ /O.CON.KMTR.BH.S.0015.000000T0000Z-201216T1100Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 938 PM PST Tue Dec 15 2020 ...BEACH HAZARDS STATEMENT REMAINS IN EFFECT UNTIL 3 AM PST WEDNESDAY... ...HIGH SURF ADVISORY REMAINS IN EFFECT FROM 3 AM TO 3 PM PST WEDNESDAY... * WHAT...For the Beach Hazards Statement infrequent yet dangerous sneaker waves are expected this evening. For the High Surf Advisory, large breaking waves of 15 to 20 feet at west to northwest facing beaches, locally up to 25 feet at favored breakpoints. * WHERE...San Francisco, Coastal North Bay Including Point Reyes National Seashore, San Francisco Peninsula Coast and Southern Monterey Bay and Big Sur Coast Counties, particularly at West and Northwest facing beaches. * WHEN...For the Beach Hazards Statement, until 3 AM PST Wednesday. For the High Surf Advisory, from 3 AM to 3 PM PST Wednesday. * IMPACTS...Sneaker waves and large breaking waves can sweep people off jetties and docks, and into dangerous seas. Cold water rescues or drownings are more likely with these waves and stronger rip currents. 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. Remain out of the water to avoid hazardous swimming conditions. && $$
982 WHUS46 KMTR 161058 CFWMTR Coastal Hazard Message National Weather Service San Francisco CA 258 AM PST Wed Dec 16 2020 ...LARGE LONG PERIOD NORTHWEST SWELL WILL CAUSE HIGH SURF ALONG THE COAST THROUGH 3 PM PST TODAY... .Another long period northwest swell will impact the coastline through today. Forerunner waves of 3 to 7 feet at 19 to 22 seconds are expected initially resulting in a brief moderate threat of sneaker waves. This swell will quickly build today generating large breaking waves of 15 to 20 feet, locally up to 25 feet at favored breakpoints. High tides will still be on the full side today morning as the King Tides only just begin to subside creating an additional danger. Thus, the surf zone and area beaches will remain hazardous into this afternoon. CAZ006-505-509-529-530-162200- /O.EXP.KMTR.BH.S.0015.000000T0000Z-201216T1100Z/ /O.CON.KMTR.SU.Y.0008.201216T1100Z-201216T2300Z/ San Francisco- Coastal North Bay Including Point Reyes National Seashore- San Francisco Peninsula Coast-Northern Monterey Bay- Southern Monterey Bay and Big Sur Coast- 258 AM PST Wed Dec 16 2020 ...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 3 PM PST THIS AFTERNOON... ...BEACH HAZARDS STATEMENT WILL EXPIRE AT 3 AM PST EARLY THIS MORNING... * WHAT...The Beach Hazards Statement expires at 3 am PST today. For the High Surf Advisory, large breaking waves of 15 to 20 feet at west to northwest facing beaches, locally up to 25 feet at favored breakpoints. * WHERE...San Francisco, Coastal North Bay Including Point Reyes National Seashore, San Francisco Peninsula Coast and Southern Monterey Bay and Big Sur Coast Counties, particularly at West and Northwest facing beaches. * WHEN...For the Beach Hazards Statement, expires at 3 AM PST today. For the High Surf Advisory, from 3 AM to 3 PM PST today. * IMPACTS...Sneaker waves and large breaking waves can sweep people off jetties and docks, and into dangerous seas. Cold water rescues or drownings are more likely with these waves and stronger rip currents. 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. Remain out of the water to avoid hazardous swimming conditions. && 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. && $$
The office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 14, 7:21 PM PST | High Surf Advisory | MTR | Marin, Monterey, City and County of San Francisco, San Mateo, Santa Cruz, Sonoma | 44 hr |
| Dec 15, 3:07 PM PST | Small Craft Advisory | MTR | 3 days |
Nearby
Beach Hazards Statements in California, 2020Every beach hazards statement in 2020
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.