Alert archive / California / Beach Hazards Statements in 2021

Beach Hazards Statement 4, NWS San Francisco Bay Area, CA

March 3, 20216 counties in California

NWS San Francisco Bay Area, CA issued this beach hazards statement at Mar 3, 2021, 2:10 PM PST for 6 counties in California. It took effect at Mar 4, 2021, 3:00 AM PST. It was in force for 24 hr.

The area

The counties it named.

The facts

Issued
Mar 3, 2021, 2:10 PM PST (22:10 UTC)
In effect from
Mar 4, 2021, 3:00 AM PST
Expired
Mar 5, 2021, 3:00 AM PST
In force
24 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 22:10 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, 10.2 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.

Skew-T log-pSkew-T log-p diagram, Oakland, CA at 12:00Z on 2021-03-03Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 12:00Z on 2021-03-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 70 square meters per square second.193958Sfc1 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
2159 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
133 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

803 
WHUS46 KMTR 032210
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
210 PM PST Wed Mar 3 2021

...INCREASED RISK OF SNEAKER WAVES AND DANGEROUS CURRENTS ON
THURSDAY...

.Long period northwest swell will arrive Thursday morning and 
will bring an increased risk of sneaker waves, rip currents, long 
shore currents, and there could be hard breaking surf on steep 
beaches. There is the potential that these conditions will
transition into high surf on Friday.

CAZ006-505-509-530-040615-
/O.NEW.KMTR.BH.S.0004.210304T1100Z-210305T1100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
210 PM PST Wed Mar 3 2021

...BEACH HAZARDS STATEMENT IN EFFECT FROM LATE TONIGHT THROUGH
LATE THURSDAY NIGHT...

* WHAT...Long period northwest swell of 8 to 11 feet at 16 to 17
  seconds expected.

* WHERE...San Francisco, Coastal North Bay Including Point Reyes 
  National Seashore, San Francisco Peninsula Coast and Southern 
  Monterey Bay and Big Sur Coast.

* WHEN...From late tonight through late Thursday night.

* IMPACTS...Increased risk of sneaker waves and stronger rip
  currents and/or long shore currents.

* ADDITIONAL DETAILS...A Beach Hazard Statement for sneaker waves
  means that 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. Avoid fishing from rocks or jetties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
5 follow-up statements
060 
WHUS46 KMTR 040447
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
847 PM PST Wed Mar 3 2021

...INCREASED RISK OF SNEAKER WAVES AND DANGEROUS CURRENTS ON
THURSDAY...

.Thursday morning has a new long period northwest swell arriving
that will bring an increased risk of sneaker waves, rip currents,
long shore currents, and there could be hard breaking surf on 
steep beaches. There is the potential that these conditions will 
transition into high surf on Friday. The hazard is for west and
northwest facing beaches where caution is advised. Never turn 
your back to the ocean.

CAZ006-505-509-530-041330-
/O.CON.KMTR.BH.S.0004.210304T1100Z-210305T1100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
847 PM PST Wed Mar 3 2021

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM 3 AM PST
THURSDAY THROUGH LATE THURSDAY NIGHT...

* WHAT...Long period northwest swell of 8 to 11 feet at 16 to 17
  seconds expected.

* WHERE...Coastal North Bay Including Point Reyes National 
  Seashore, Southern Monterey Bay and Big Sur Coast, San 
  Francisco Peninsula Coast and San Francisco.

* WHEN...From 3 AM PST Thursday through late Thursday night.

* IMPACTS...Increased risk of sneaker waves and stronger rip
  currents and/or long shore currents.

* ADDITIONAL DETAILS...A Beach Hazard Statement for sneaker waves
  means that 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. Avoid fishing from rocks or jetties. The coastal waters
  remain cold. Cold water shock may cause cardiac arrest, and it 
  also can cause an involuntary gasp reflex causing drowning, even
  for a good swimmer. The surf zone will be dangerous due to 
  strong currents and powerful breaking waves.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions. 
The coastal waters remain cold. Cold water shock may cause cardiac
arrest, and it also can cause an involuntary gasp reflex causing 
drowning, even for a good swimmer. The surf zone will be dangerous
due to strong currents and powerful breaking waves.

&&

$$
374 
WHUS46 KMTR 041324
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
524 AM PST Thu Mar 4 2021

...INCREASING RISK OF SNEAKER WAVES AND DANGEROUS CURRENTS TODAY 
THROUGH LATE TONIGHT...

.A new long period northwest swell arrives today through Friday that
will bring an increasing risk of sneaker waves, rip currents, long
shore currents, and there could be hard breaking surf on steep 
beaches. There is the potential that these conditions will 
transition into high surf on Friday. The hazard is for west and 
northwest facing beaches where caution is advised. Never turn your
back to the ocean.

CAZ006-505-509-530-042200-
/O.CON.KMTR.BH.S.0004.000000T0000Z-210305T1100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
524 AM PST Thu Mar 4 2021

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH LATE
TONIGHT...

* WHAT...Long period northwest swell of 8 to 11 feet at 16 to 17 
  seconds expected.

* WHERE...Coastal North Bay Including Point Reyes National 
  Seashore, Southern Monterey Bay and Big Sur Coast, San 
  Francisco Peninsula Coast and San Francisco.

* WHEN...From 3 AM PST today through late tonight.

* IMPACTS...Increased risk of sneaker waves and stronger rip 
  currents and/or long shore currents.

* ADDITIONAL DETAILS...A Beach Hazard Statement for sneaker waves
  means that 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. Avoid fishing from rocks or jetties. The coastal waters
  remain cold. Cold water shock may cause cardiac arrest, and it 
  also can cause an involuntary gasp reflex causing drowning, even
  for a good swimmer. The surf zone will be dangerous due to 
  strong currents and powerful breaking waves.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions. 
The coastal waters remain cold. Cold water shock may cause cardiac
arrest, and it also can cause an involuntary gasp reflex causing 
drowning, even for a good swimmer. The surf zone will be dangerous
due to strong currents and powerful breaking waves.

&&

$$
735 
WHUS46 KMTR 042157
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
157 PM PST Thu Mar 4 2021

...INCREASING RISK OF SNEAKER WAVES AND DANGEROUS CURRENTS TODAY
THROUGH LATE TONIGHT...

.A long period northwest swell arrives this afternoon continuing 
through Friday that will bring an increased risk of sneaker 
waves, rip currents, long shore currents, and there could be hard 
breaking surf on steep beaches. The hazard is for west and 
northwest facing beaches where caution is advised. Never turn your
back to the ocean.

CAZ006-505-509-530-051100-
/O.CON.KMTR.BH.S.0004.000000T0000Z-210305T1100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
157 PM PST Thu Mar 4 2021

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH LATE
TONIGHT...

* WHAT...Long period northwest swell of 8 to 11 feet at 16 to 17 
  seconds expected.

* WHERE...Coastal North Bay Including Point Reyes National 
  Seashore, Southern Monterey Bay and Big Sur Coast, San 
  Francisco Peninsula Coast and San Francisco.

* WHEN...From 3 AM PST today through late tonight.

* IMPACTS...Increased risk of sneaker waves and stronger rip 
  currents and/or long shore currents.

* ADDITIONAL DETAILS...A Beach Hazard Statement for sneaker 
  waves means that 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. Avoid fishing from rocks or 
  jetties. The coastal waters remain cold. Cold water shock may 
  cause cardiac arrest, and it also can cause an involuntary 
  gasp reflex causing drowning, even for a good swimmer. The 
  surf zone will be dangerous due to strong currents and 
  powerful breaking waves.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
027 
WHUS46 KMTR 050420
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
820 PM PST Thu Mar 4 2021

...INCREASING RISK OF SNEAKER WAVES AND DANGEROUS CURRENTS TODAY
THROUGH LATE TONIGHT...

.As the long period northwest continues to move southward through
Friday, it will bring an increased risk of sneaker waves, rip 
currents, long shore currents, and there could be hard breaking 
surf on steep beaches. The hazard is for west and northwest facing
beaches where caution is advised. Never turn your back to the 
ocean.

CAZ006-505-509-530-051100-
/O.CON.KMTR.BH.S.0004.000000T0000Z-210305T1100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
820 PM PST Thu Mar 4 2021

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT UNTIL 3 AM PST
FRIDAY...

* WHAT...Long period northwest swell of 8 to 11 feet at 16 to 17 
  seconds expected

* WHERE...Coastal North Bay Including Point Reyes National 
  Seashore, Southern Monterey Bay and Big Sur Coast, San 
  Francisco Peninsula Coast and San Francisco.

* WHEN...Until 3 AM PST Friday.

* IMPACTS...Increased risk of sneaker waves and stronger rip 
  currents and/or long shore currents.

* ADDITIONAL DETAILS...A Beach Hazard Statement for sneaker 
  waves means that 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. Avoid fishing from rocks or 
  jetties. The coastal waters remain cold. Cold water shock may 
  cause cardiac arrest, and it also can cause an involuntary 
  gasp reflex causing drowning, even for a good swimmer. The 
  surf zone will be dangerous due to strong currents and 
  powerful breaking waves.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
987 
WHUS46 KMTR 051053
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
253 AM PST Fri Mar 5 2021

CAZ006-505-509-530-051200-
/O.EXP.KMTR.BH.S.0004.000000T0000Z-210305T1100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
253 AM PST Fri Mar 5 2021

...BEACH HAZARDS STATEMENT WILL EXPIRE AT 3 AM PST EARLY THIS
MORNING...

The long period northwest swell will continue to subside. 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 3, 2:26 AM PSTSmall Craft AdvisoryMTR8 days

Nearby

Beach Hazards Statements in California, 2021Every beach hazards statement 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.