Alert archive / California / Beach Hazards Statements in 2020

Beach Hazards Statement 7, NWS San Francisco Bay Area, CA

April 18, 20206 counties in California

NWS San Francisco Bay Area, CA issued this beach hazards statement at Apr 18, 2020, 9:07 PM PDT for 6 counties in California. It took effect at Apr 19, 2020, 11:00 PM PDT. It was in force for 24 hr.

The area

The counties it named.

The facts

Issued
Apr 18, 2020, 9:07 PM PDT (04:07 UTC)
In effect from
Apr 19, 2020, 11:00 PM PDT
Expired
Apr 20, 2020, 11:00 PM PDT
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 04:12 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, 4.1 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 00:00Z on 2020-04-19Temperature 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 00:00Z on 2020-04-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -49 square meters per square second.19395878Sfc1 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
1308 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
-49 m²/s²
0-3 km storm-relative helicity
-4 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

995 
WHUS46 KMTR 190407
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
907 PM PDT Sat Apr 18 2020

...Increasing risk of sneaker waves and strong rip currents from
Coastal Sonoma County to Coastal Monterey County Sunday night...

A long-period northwest swell will arrive along the beaches Sunday
night and continue through Monday night. Swell period of 18 to 20
seconds will increase the risks for sneaker waves and rip currents.
The ocean may seem relatively calm for periods of times with 
infrequent larger waves capable of knocking unsuspecting people 
into the ocean. People visiting the beaches should use extra
caution when venturing into the ocean.  


CAZ006-505-509-529-530-200600-
/O.NEW.KMTR.BH.S.0007.200420T0600Z-200421T0600Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
907 PM PDT Sat Apr 18 2020

...BEACH HAZARDS STATEMENT IN EFFECT FROM SUNDAY EVENING THROUGH
MONDAY EVENING...

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

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

* WHEN...From Sunday evening through Monday evening.

* 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...Please check with your local authorities on
  potential beach closures. Steep beaches will have a higher risk
  of sneaker wave and rip current activity with greater wave run- p
  onto beaches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
4 follow-up statements
631 
WHUS46 KMTR 200331
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
831 PM PDT Sun Apr 19 2020

...Increasing risk of sneaker waves and strong rip currents from
Coastal Sonoma County to Coastal Monterey County tonight through
Monday night...

A long-period northwest swell will arrive along the beaches
tonight and continue through Monday night. Swell period of 18 to 
20 seconds will increase the risks for sneaker waves and rip 
currents. The ocean may seem relatively calm for periods of times 
with infrequent larger waves capable of knocking unsuspecting 
people into the ocean. People visiting the beaches should use 
extra caution when venturing near or into the ocean.

CAZ006-505-509-529-530-201600-
/O.CON.KMTR.BH.S.0007.200420T0600Z-200421T0600Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
831 PM PDT Sun Apr 19 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH MONDAY
EVENING...

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

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

* WHEN...From this evening through Monday evening.

* 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...Please check with your local authorities 
  on potential beach closures. Steep beaches will have a higher 
  risk of sneaker wave and rip current activity with greater 
  wave run- p onto beaches. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
987 
WHUS46 KMTR 201309
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
609 AM PDT Mon Apr 20 2020

...Increasing risk of sneaker waves and strong rip currents from
Coastal Sonoma County to Coastal Monterey County through Monday 
night...

A long-period northwest swell will continue to move across the
coastal waters today and through tonight. Swell period of 17 to 
19 seconds will increase the risks for sneaker waves and rip 
currents. The ocean may seem relatively calm for periods of times 
with infrequent larger waves capable of knocking unsuspecting 
people into the ocean. People visiting the beaches should use 
extra caution when venturing near or into the ocean.

CAZ006-505-509-529-530-210600-
/O.CON.KMTR.BH.S.0007.000000T0000Z-200421T0600Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
609 AM PDT Mon Apr 20 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THIS
EVENING...

* WHAT...Increased risk of sneaker waves and rip currents 
  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 this evening.

* 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...Please check with your local authorities on
  potential beach closures. 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.

&&

$$
685 
WHUS46 KMTR 202147
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
247 PM PDT Mon Apr 20 2020

...Increasing risk of sneaker waves and strong rip currents from
Coastal Sonoma County to Coastal Monterey County through Monday
night...

A long-period northwest swell will continue to move across the
coastal waters today and through tonight. Swell period of 17 to
19 seconds will increase the risks for sneaker waves and rip
currents. The ocean may seem relatively calm for periods of times
with infrequent larger waves capable of knocking unsuspecting
people into the ocean. People visiting the beaches should use
extra caution when venturing near or into the ocean.

CAZ006-505-509-529-530-210600-
/O.CON.KMTR.BH.S.0007.000000T0000Z-200421T0600Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
247 PM PDT Mon Apr 20 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT UNTIL 11 PM PDT THIS
EVENING...

* WHAT...Increased risk of sneaker waves and rip currents 
  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 this evening.

* 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...Please check with your local authorities 
  on potential beach closures. 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.

&&

$$
173 
WHUS46 KMTR 210545
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
1045 PM PDT Mon Apr 20 2020


CAZ006-505-509-529-530-210645-
/O.EXP.KMTR.BH.S.0007.000000T0000Z-200421T0600Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
1045 PM PDT Mon Apr 20 2020

...BEACH HAZARDS STATEMENT WILL EXPIRE AT 11 PM PDT THIS
EVENING...

Long period northwest swell will continue to decrease tonight and
Tuesday. The Beach Hazards Statement will be allowed to expire at
11 pm this evening.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 19, 2:52 AM PDTSmall Craft AdvisoryMTR19 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.