Alert archive / California / Beach Hazards Statements in 2020

Beach Hazards Statement 11, NWS San Francisco Bay Area, CA

November 29, 20206 counties in California

NWS San Francisco Bay Area, CA issued this beach hazards statement at Nov 29, 2020, 5:59 AM PST for 6 counties in California. It took effect at Nov 30, 2020, 10:00 AM PST. It was in force for 24 hr.

The area

The counties it named.

The facts

Issued
Nov 29, 2020, 5:59 AM PST (13:59 UTC)
In effect from
Nov 30, 2020, 10:00 AM PST
Expired
Dec 1, 2020, 10:00 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 14:03 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, 2.0 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 2020-11-29Temperature 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 2020-11-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -1 square meters per square second.1939Sfc1 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
2410 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
-17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

289 
WHUS46 KMTR 291359
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
559 AM PST Sun Nov 29 2020

...Sneaker waves and strong rip currents for west and northwest 
facing beaches from coastal Sonoma County to coastal Monterey 
County Monday into Tuesday...

.A long period northwest swell will arrive late Monday morning and
impact the coastline through late Tuesday morning before subsiding.
Initial swell heights of 7 to 9 feet at 19 seconds will increase 
the risk of sneaker waves Monday. Swell heights will build to 9 to
11 feet at 17 seconds to 18 seconds Monday night and early Tuesday
morning before subsiding late Tuesday morning. 

CAZ006-505-509-529-530-300500-
/O.NEW.KMTR.BH.S.0011.201130T1800Z-201201T1800Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
559 AM PST Sun Nov 29 2020

...BEACH HAZARDS STATEMENT IN EFFECT FROM 10 AM PST MONDAY 
MORNING THROUGH 10 AM PST TUESDAY MORNING...

* HAZARDS...Breaking waves initially from 7 to 9 feet at 19
  seconds Monday, then breaks from 9 to 11 feet at 17 seconds to
  18 seconds Monday night and early Tuesday morning. 

* TIMING...10 AM PST Monday to 10 AM Tuesday.

* LOCATION...Coastal Sonoma County to coastal Monterey County, in
  particular west to northwest facing beaches.

* POTENTIAL IMPACTS...Increased risk of ocean drowning. Sneaker
  waves often catch people off guard and knock them into the
  ocean. Rip currents can pull swimmers and surfers out to sea.
  large breaking waves can cause injury, wash people off beaches
  and rocks, and capsize small boats near shore. Use extreme
  caution near the surf zone as large waves will be capable of
  sweeping people into the frigid and turbulent ocean water. Cold
  water shock may cause cardiac arrest, and it also can cause an
  involuntary gasp reflex causing drowning, even for a good 
  swimmer.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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. Fisherman should 
avoid fishing from rocks or jetties.

A Beach Hazard Statement for rip currents means that conditions
are present to support a heightened risk of strong rip currents.
Rip currents are typically more frequent and stronger in the
vicinity of jetties...inlets...and piers. Swimmers caught in a
rip current should swim parallel to the coast to escape the rip
current before trying to swim for shore. Swimmers should always
swim near a lifeguard.

Please listen to NOAA Weather Radio or your local media for the 
latest updates on this situation.

&&

$$
6 follow-up statements
301 
WHUS46 KMTR 292113
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
113 PM PST Sun Nov 29 2020

...Sneaker waves and strong rip currents for west and northwest
facing beaches from coastal Sonoma County to coastal Monterey
County Monday into Tuesday...

.A long period northwest swell will arrive late Monday morning
and impact the coastline through late Tuesday morning before
subsiding. Initial swell heights of 7 to 9 feet at 19 seconds
will increase the risk of sneaker waves Monday. Swell heights
will build to 9 to 11 feet at 17 seconds to 18 seconds Monday
night and early Tuesday morning before subsiding late Tuesday
morning. An even longer period northwest swell will arrive 
Wednesday resulting in an even greater risk of these hazards.

CAZ006-505-509-529-530-300500-
/O.CON.KMTR.BH.S.0011.201130T1800Z-201201T1800Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
113 PM PST Sun Nov 29 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM MONDAY MORNING
THROUGH TUESDAY MORNING...

* HAZARDS...Increased risk of sneaker waves and rip currents,
  especially along the west and northwest facing beaches.
  Additionally, breaking waves initially from 7 to 9 feet at 19
  seconds Monday, then breaks from 9 to 11 feet at 17 seconds to
  18 seconds Monday night and early Tuesday morning.

* TIMING...10 AM PST Monday to 10 AM Tuesday.

* LOCATION...Coastal Sonoma County to coastal Monterey County, 
  in particular west to northwest facing beaches.

* ADDITIONAL DETAILS...An even longer period northwest swell will
  arrive Wednesday and continue through Thursday producing an even
  greater risk for sneaker waves and rip currents.

* POTENTIAL IMPACTS...Increased risk of ocean drowning. Sneaker
  waves often catch people off guard and knock them into the
  ocean. Rip currents can pull swimmers and surfers out to sea. 
  Large breaking waves can cause injury, wash people off beaches 
  and rocks, and capsize small boats near shore. Use extreme 
  caution near the surf zone as large waves will be capable of 
  sweeping people into the frigid and turbulent ocean water. Cold 
  water shock may cause cardiac arrest, and it also can cause an 
  involuntary gasp reflex causing drowning, even for a good 
  swimmer.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
972 
WHUS46 KMTR 300454
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
854 PM PST Sun Nov 29 2020

...Sneaker waves and strong rip currents for west and northwest
facing beaches from coastal Sonoma County to coastal Monterey
County Monday into Tuesday...

.A long period northwest swell will arrive late Monday morning
and impact the coastline through late Tuesday morning before
subsiding. Initial swell heights of 7 to 9 feet at 19 seconds
will increase the risk of sneaker waves Monday. Swell heights
will build to 9 to 11 feet at 17 seconds to 18 seconds Monday
night and early Tuesday morning before subsiding late Tuesday
morning. An even longer period northwest swell will arrive
Wednesday resulting in an even greater risk of these hazards.

CAZ006-505-509-529-530-301100-
/O.CON.KMTR.BH.S.0011.201130T1800Z-201201T1800Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
854 PM PST Sun Nov 29 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM MONDAY MORNING
THROUGH TUESDAY MORNING...

* HAZARDS...Increased risk of sneaker waves and rip currents, 
  especially along the west and northwest facing beaches. 
  Additionally, breaking waves initially from 7 to 9 feet at 19 
  seconds Monday, then breaks from 9 to 11 feet at 17 seconds to 
  18 seconds Monday night and early Tuesday morning. 

* TIMING...10 AM PST Monday to 10 AM Tuesday.

* LOCATION...Coastal Sonoma County to coastal Monterey County, 
  in particular west to northwest facing beaches. 

* ADDITIONAL DETAILS...An even longer period northwest swell 
  will arrive Wednesday and continue through Thursday producing 
  an even greater risk for sneaker waves and rip currents. 

* POTENTIAL IMPACTS...Increased risk of ocean drowning. Sneaker 
  waves often catch people off guard and knock them into the 
  ocean. Rip currents can pull swimmers and surfers out to sea. 
  Large breaking waves can cause injury, wash people off beaches 
  and rocks, and capsize small boats near shore. Use extreme 
  caution near the surf zone as large waves will be capable of 
  sweeping people into the frigid and turbulent ocean water. 
  Cold water shock may cause cardiac arrest, and it also can 
  cause an involuntary gasp reflex causing drowning, even for a 
  good swimmer. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
179 
WHUS46 KMTR 300940
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
140 AM PST Mon Nov 30 2020

...Sneaker waves and strong rip currents for west and northwest
facing beaches from coastal Sonoma County to coastal Monterey
County today into Tuesday...

.A long period northwest swell will arrive later this morning and
impact the coastline through late Tuesday morning before subsiding.
Initial swell heights of 7 to 9 feet at 19 seconds will increase 
the risk of sneaker waves today. Swell heights will build to 9 to
11 feet at 17 seconds to 18 seconds tonight and early Tuesday 
morning before subsiding late Tuesday morning. An even longer 
period northwest swell will arrive Wednesday resulting in an even 
greater risk of these hazards.

CAZ006-505-509-529-530-010500-
/O.CON.KMTR.BH.S.0011.201130T1800Z-201201T1800Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
140 AM PST Mon Nov 30 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM 10 AM PST THIS
MORNING THROUGH 10 AM PST TUESDAY MORNING...

* HAZARDS...Increased risk of sneaker waves and rip currents,
  especially along the west and northwest facing beaches.
  Additionally, breaking waves initially from 7 to 9 feet at 19
  seconds today, then breaks from 9 to 11 feet at 17 seconds to 18
  seconds tonight and early Tuesday morning. 

* TIMING...10 AM PST today to 10 AM Tuesday.

* LOCATION...Coastal Sonoma County to coastal Monterey County, 
  in particular west to northwest facing beaches. 

* ADDITIONAL DETAILS...An even longer period northwest swell 
  will arrive Wednesday and continue through Thursday producing 
  an even greater risk for sneaker waves and rip currents. 

* POTENTIAL IMPACTS...Increased risk of ocean drowning. Sneaker 
  waves often catch people off guard and knock them into the 
  ocean. Rip currents can pull swimmers and surfers out to sea. 
  Large breaking waves can cause injury, wash people off beaches 
  and rocks, and capsize small boats near shore. Use extreme 
  caution near the surf zone as large waves will be capable of 
  sweeping people into the frigid and turbulent ocean water. 
  Cold water shock may cause cardiac arrest, and it also can 
  cause an involuntary gasp reflex causing drowning, even for a 
  good swimmer. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
279 
WHUS46 KMTR 301729
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
929 AM PST Mon Nov 30 2020

...Enhanced Risk of Sneaker waves and rip currents for west and 
northwest facing beaches Late Monday Morning into Tuesday...

.A long period northwest swell arrives this morning and will 
impact the coastline through late Tuesday morning before 
subsiding. Initial swell heights of 7 to 9 feet at 19 seconds will
increase the risk of sneaker waves today. Swell heights will 
build to 9 to 11 feet at 17 seconds to 18 seconds tonight and 
early Tuesday morning before subsiding late Tuesday morning. A 
much longer period swell train arrives Wednesday and result in a 
much greater risk of these hazards.

CAZ529-301830-
/O.CAN.KMTR.BH.S.0011.201130T1800Z-201201T1800Z/
Northern Monterey Bay-
929 AM PST Mon Nov 30 2020

...BEACH HAZARDS STATEMENT IS CANCELLED...

The National Weather Service in San Francisco has cancelled the
Beach Hazards Statement. 

Due to the NW swell direction, the Northern Monterey Bay south
facing beaches will be shielded from this event.

$$

CAZ006-505-509-530-010500-
/O.CON.KMTR.BH.S.0011.201130T1800Z-201201T1800Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
929 AM PST Mon Nov 30 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH TUESDAY
MORNING...

* HAZARDS...Increased risk of sneaker waves and rip currents,
  especially along the west and northwest facing beaches.
  Additionally, breaking waves initially from 7 to 10 feet at 19
  seconds today, then breaks from 10 to 13 feet at 17 seconds to 
  18 seconds tonight and early Tuesday morning. 

* TIMING...10 AM PST today to 10 AM Tuesday.

* LOCATION...Coastal Sonoma County to coastal Monterey County, in
  particular west to northwest facing beaches. Excludes the
  Northern Monterey Bay beaches due to their southerly
  orientation.

* ADDITIONAL DETAILS...A much longer period northwest swell will
  arrive Wednesday and continue through Thursday and result in a
  much greater risk for sneaker waves and rip currents. 

* POTENTIAL IMPACTS...Increased risk of ocean drowning. Sneaker 
  waves often catch people off guard and knock them into the 
  ocean. Rip currents can pull swimmers and surfers out to sea. 
  Large breaking waves can cause injury, wash people off beaches 
  and rocks, and capsize small boats near shore. Use extreme 
  caution near the surf zone as large waves will be capable of 
  sweeping people into the frigid and turbulent ocean water. 
  Cold water shock may cause cardiac arrest, and it also can 
  cause an involuntary gasp reflex causing drowning, even for a 
  good swimmer. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
931 
WHUS46 KMTR 010411
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
811 PM PST Mon Nov 30 2020

...Enhanced Risk of Sneaker Waves and Rip Currents for west and
northwest facing beaches into Tuesday...

.A long period northwest swell will continue to impact the 
coastline through late Tuesday morning before subsiding. Swell 
heights of 9 to 11 feet at 17 seconds to 18 seconds are expected tonight
and early Tuesday morning before subsiding late Tuesday morning. 
A much longer period swell train arrives Wednesday and will result
in a much greater risk of sneaker waves and rip currents.

CAZ006-505-509-530-011800-
/O.CON.KMTR.BH.S.0011.000000T0000Z-201201T1800Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
811 PM PST Mon Nov 30 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH TUESDAY
MORNING...

* HAZARDS...Increased risk of sneaker waves and rip currents,
  especially along the west and northwest facing beaches.
  Additionally, breaking waves from 10 to 13 feet at 17 seconds to
  18 seconds into early Tuesday morning.

* TIMING...Remains in effect until 10 AM Tuesday.

* LOCATION...Coastal Sonoma County to coastal Monterey County, 
  in particular west to northwest facing beaches. Excludes the 
  Northern Monterey Bay beaches due to their southerly 
  orientation.

* ADDITIONAL DETAILS...A much longer period northwest swell will
  arrive Wednesday and continue through Thursday and result in a
  much greater risk for sneaker waves and rip currents.

* POTENTIAL IMPACTS...Increased risk of ocean drowning. Sneaker 
  waves often catch people off guard and knock them into the 
  ocean. Rip currents can pull swimmers and surfers out to sea. 
  Large breaking waves can cause injury, wash people off beaches 
  and rocks, and capsize small boats near shore. Use extreme 
  caution near the surf zone as large waves will be capable of 
  sweeping people into the frigid and turbulent ocean water. 
  Cold water shock may cause cardiac arrest, and it also can 
  cause an involuntary gasp reflex causing drowning, even for a 
  good swimmer.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
951 
WHUS46 KMTR 011747
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
947 AM PST Tue Dec 1 2020

CAZ006-505-509-530-011900-
/O.EXP.KMTR.BH.S.0011.000000T0000Z-201201T1800Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
947 AM PST Tue Dec 1 2020

...BEACH HAZARDS STATEMENT WILL EXPIRE AT 10 AM PST THIS
MORNING...

Moderate breaking waves along the coast are possible through the
remainder of the day so remain vigilant if visiting the coast. 

A much longer period northwest swell arrives tomorrow through 
Thursday which will bring a very high risk of stronger than usual 
sneaker waves and rip currents. A new Beach Hazard Statement for 
the Wednesday to Thursday event will be issued later today.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Nov 29, 4:07 AM PSTSmall Craft AdvisoryMTR57 hr
Nov 29, 2:39 PM PSTSmall Craft AdvisoryMTR42 hr

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.