Alert archive / California / Beach Hazards Statements in 2020

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

March 20, 20206 counties in California

NWS San Francisco Bay Area, CA issued this beach hazards statement at Mar 20, 2020, 12:56 PM PDT for 6 counties in California. It took effect at Mar 21, 2020, 8:00 PM PDT. It was in force for 31 hr.

The area

The counties it named.

The facts

Issued
Mar 20, 2020, 12:56 PM PDT (19:56 UTC)
In effect from
Mar 21, 2020, 8:00 PM PDT
Expired
Mar 23, 2020, 3:00 AM PDT
In force
31 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 19:58 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, 7.9 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 2020-03-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3 joules per kilogram.LCLLFCEL10008507005003002001001 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 2020-03-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -20 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
3 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
770 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
-20 m²/s²
0-3 km storm-relative helicity
-6 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

896 
WHUS46 KMTR 201956
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
1256 PM PDT Fri Mar 20 2020

...Increased Risk of Sneaker Waves and Rip Currents Saturday 
Evening until late Sunday Night...

.A long period northwest swell will move into the coastal waters
Saturday evening increasing the risk of sneaker waves and rip
currents along the coastline from Sonoma County through Monterey 
County. The greatest risk for sneaker waves will occur Saturday 
evening through Sunday morning. Northwest swell of 2 to 5 feet at 
18 to 21 seconds is anticipated. Swell periods will gradually 
decrease Sunday night and Monday.

CAZ006-505-509-529-530-210400-
/O.NEW.KMTR.BH.S.0004.200322T0300Z-200323T1000Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
1256 PM PDT Fri Mar 20 2020

...BEACH HAZARDS STATEMENT IN EFFECT FROM SATURDAY EVENING
THROUGH LATE SUNDAY NIGHT...

* WHAT...Increased risk of sneaker waves and rip currents are expected.

* WHERE...Coastline from Sonoma County southward through Monterey
  County. In particular west to northwest facing beaches...including
  but not limited to...Ocean Beach...Montara State Beach and 
  Marina State Beach..

* WHEN...From Saturday evening through late Sunday night.

* IMPACTS...Sneaker waves can knock unsuspecting beach goers over
  and into the sea. Rip currents can pull swimmers and surfers out
  to sea.

* ADDITIONAL DETAILS...Steep beaches will have a higher risk of
  sneaker wave and rip current activity with greater wave run-up 
  onto beaches.

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. Rip currents are 
typically more frequent and stronger in the vicinity of 
jetties...inlets...and piers. People walking along the beach 
should never turn their back to the sea. Fisherman should avoid 
fishing from rocks or jetties. Remain out of the water to avoid 
hazardous swimming conditions. Anyone caught in a rip current 
should swim parallel to the coast to escape the rip current before
trying to swim for shore.


&&

$$
6 follow-up statements
596 
WHUS46 KMTR 210619
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
1119 PM PDT Fri Mar 20 2020

...Increased Risk of Sneaker Waves and Rip Currents Saturday
Evening until late Sunday Night...

.A long period northwest swell will move into the coastal waters
Saturday evening increasing the risk of sneaker waves and rip
currents along the coastline from Sonoma County through Monterey
County. The greatest risk for sneaker waves will occur Saturday
evening through Sunday morning. Northwest swell of 2 to 5 feet at
18 to 21 seconds is anticipated. Swell periods will gradually
decrease Sunday night and Monday.

CAZ006-505-509-529-530-211700-
/O.CON.KMTR.BH.S.0004.200322T0300Z-200323T1000Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
1119 PM PDT Fri Mar 20 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM SATURDAY
EVENING THROUGH LATE SUNDAY NIGHT...

* WHAT...Increased risk of sneaker waves and rip currents are 
  expected.

* WHERE...Coastline from Sonoma County southward through 
  Monterey County. In particular west to northwest facing 
  beaches... including but not limited to...Ocean Beach...
  Montara State Beach and Marina State Beach.. 

* WHEN...From Saturday evening through late Sunday night.

* IMPACTS...Sneaker waves can knock unsuspecting beach goers 
  over and into the sea. Rip currents can pull swimmers and 
  surfers out to sea. 

* ADDITIONAL DETAILS...Steep beaches will have a higher risk of 
  sneaker wave and rip current activity with greater wave run-up 
  onto beaches. 

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. Rip currents are
typically more frequent and stronger in the vicinity of jetties...
inlets...and piers. People walking along the beach should never
turn their back to the sea. Fisherman should avoid fishing from
rocks or jetties. Remain out of the water to avoid hazardous
swimming conditions. Anyone caught in a rip current should swim
parallel to the coast to escape the rip current before trying to
swim for shore.

&&

$$
437 
WHUS46 KMTR 211547
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
847 AM PDT Sat Mar 21 2020

...Increased Risk of Sneaker Waves and Rip Currents from this 
Evening until late Sunday Night...

.A long period northwest swell will move into the coastal waters
this evening increasing the risk of sneaker waves and rip 
currents along the coastline from Sonoma County through Monterey 
County. The greatest risk for sneaker waves will occur Saturday 
evening through Sunday morning. Northwest swell of 2 to 5 feet at 
18 to 21 seconds is anticipated. Swell periods will gradually 
decrease Sunday night and Monday.

CAZ006-505-509-529-530-221000-
/O.CON.KMTR.BH.S.0004.200322T0300Z-200323T1000Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
847 AM PDT Sat Mar 21 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM 8 PM PDT THIS
EVENING THROUGH LATE SUNDAY NIGHT...

* WHAT...Increased risk of sneaker waves and rip currents are 
  expected.

* 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 Counties.

* WHEN...From 8 PM PDT this evening through late Sunday night.

* IMPACTS...Sneaker waves can knock unsuspecting beach goers 
  over and into the sea. Rip currents can pull swimmers and 
  surfers out to sea. 

* ADDITIONAL DETAILS...Steep beaches will have a higher risk of 
  sneaker wave and rip current activity with greater wave run-up 
  onto beaches. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
028 
WHUS46 KMTR 220546
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
1046 PM PDT Sat Mar 21 2020

...Increased Risk of Sneaker Waves and Rip Currents from this
Evening until late Sunday Night...

.A long period northwest swell will move into the coastal waters
this evening increasing the risk of sneaker waves and rip
currents along the coastline from Sonoma County through Monterey
County. The greatest risk for sneaker waves will occur Saturday
evening through Sunday morning. Northwest swell of 2 to 5 feet at
18 to 21 seconds is anticipated. Swell periods will gradually
decrease Sunday night and Monday.

CAZ006-505-509-529-530-221400-
/O.CON.KMTR.BH.S.0004.000000T0000Z-200323T1000Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
1046 PM PDT Sat Mar 21 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH LATE SUNDAY
NIGHT...

* WHAT...Increased risk of sneaker waves and rip currents are 
  expected. 

* 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 Counties. 

* WHEN...Through late Sunday night.

* IMPACTS...Sneaker waves can knock unsuspecting beach goers 
  over and into the sea. Rip currents can pull swimmers and 
  surfers out to sea. 

* ADDITIONAL DETAILS...Steep beaches will have a higher risk of 
  sneaker wave and rip current activity with greater wave run-up 
  onto beaches. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
535 
WHUS46 KMTR 221003
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
303 AM PDT Sun Mar 22 2020

...Increased Risk of Sneaker Waves and Rip Currents from this
Evening until late Sunday Night...

.A long period northwest swell will move into the coastal waters
through late Sunday evening, increasing the risk of sneaker waves
and rip currents along the coastline from Sonoma County through 
Monterey County. Northwest swell of 2 to 5 feet at 18 to 21 
seconds is anticipated. Swell periods will gradually decrease 
Sunday night and Monday.

CAZ006-505-509-529-530-222200-
/O.CON.KMTR.BH.S.0004.000000T0000Z-200323T1000Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
303 AM PDT Sun Mar 22 2020

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

* WHAT...Increased risk of sneaker waves and rip currents are 
  expected. 

* 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 Counties. 

* WHEN...Through late Sunday night.

* IMPACTS...Sneaker waves can knock unsuspecting beach goers 
  over and into the sea. Rip currents can pull swimmers and 
  surfers out to sea. 

* ADDITIONAL DETAILS...Steep beaches will have a higher risk of 
  sneaker wave and rip current activity with greater wave run-up 
  onto beaches. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
451 
WHUS46 KMTR 222201
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
301 PM PDT Sun Mar 22 2020

...Increased Risk of Sneaker Waves and Rip Currents through late 
Sunday Night...

.A long period northwest swell will pass through the coastal 
waters through late Sunday night, increasing the risk of sneaker 
waves and rip currents along the coastline from Sonoma County 
through Monterey County. Northwest swell of 2 to 5 feet at 18 to 
19 seconds is occurring. Swell periods will gradually decrease 
by Monday.

CAZ006-505-509-529-530-231000-
/O.CON.KMTR.BH.S.0004.000000T0000Z-200323T1000Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
301 PM PDT Sun Mar 22 2020

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

* WHAT...Increased risk of sneaker waves and rip currents.
 
* 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 Counties.

* WHEN...Through late tonight.

* IMPACTS...Sneaker waves can knock unsuspecting beach goers over
  and into the sea. Rip currents can pull swimmers and surfers out
  to sea.

* ADDITIONAL DETAILS...Steep beaches will have a higher risk of
  sneaker wave and rip current activity with greater wave run-up
  onto beaches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
050 
WHUS46 KMTR 230942
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
242 AM PDT Mon Mar 23 2020

...The Beach Hazard Statement will expire at 3 AM PDT...

.Due to continued decreasing period of the northwest swell, the
beach hazard statement will be allowed to expire at 3 AM PDT early
Monday morning. Caution is still advised for anyone along the
coastline as sneaker waves and rip currents may still be present.
Remember, never turn your back to the ocean.

CAZ006-505-509-529-530-231045-
/O.EXP.KMTR.BH.S.0004.000000T0000Z-200323T1000Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
242 AM PDT Mon Mar 23 2020

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

$$

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.