Alert archive / California / Beach Hazards Statements in 2021

Beach Hazards Statement 6, NWS San Francisco Bay Area, CA

March 19, 20216 counties in California

NWS San Francisco Bay Area, CA issued this beach hazards statement at Mar 19, 2021, 3:38 AM PDT for 6 counties in California. It took effect at Mar 19, 2021, 10:00 AM PDT. It was in force for 12 hr.

The area

The counties it named.

The facts

Issued
Mar 19, 2021, 3:38 AM PDT (10:38 UTC)
In effect from
Mar 19, 2021, 10:00 AM PDT
Expired
Mar 19, 2021, 10:00 PM PDT
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 10:41 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

Vandenberg AFB, CA (KVBG), launched 00:00Z, 10.6 hours before the alert went out and 349 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, Vandenberg AFB, CA at 00:00Z on 2021-03-19Temperature 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, Vandenberg AFB, CA at 00:00Z on 2021-03-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 5 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
1120 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
5 m²/s²
0-3 km storm-relative helicity
18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

771 
WHUS46 KMTR 191038
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
338 AM PDT Fri Mar 19 2021

...Increasing risk of large breaking waves, strong rip currents
and sneaker waves from late morning to this evening...

.A large, moderate period northwest swell will arrive in our 
coastal waters later this morning and continue into late evening.
Expect an increasing risk of large breaking waves, strong rip
currents and sneaker waves by late morning into tonight. The
hazard is for west to northwest facing beaches where caution is
advised. Northwest swell will subside late tonight and Saturday. 


CAZ006-505-509-529-530-192100-
/O.NEW.KMTR.BH.S.0006.210319T1700Z-210320T0600Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
338 AM PDT Fri Mar 19 2021

...BEACH HAZARDS STATEMENT IN EFFECT FROM 10 AM PDT THIS MORNING
TO 10 PM PDT THIS EVENING...

* WHAT...Northwest swell 13 to 15 feet at 15 seconds expected.

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

* WHEN...From 10 AM PDT this morning to 10 PM PDT this evening.

* IMPACTS...Increasing risk of large breaking waves, strong rip
  currents and sneaker waves.

* ADDITIONAL DETAILS...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 large breaking waves, strong rip currents and
  sneaker waves.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
2 follow-up statements
648 
WHUS46 KMTR 192053
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
153 PM PDT Fri Mar 19 2021

...Increasing risk of large breaking waves, strong rip currents
and sneaker waves through this evening...

.A large, moderate period northwest swell will continue to build
into the region through late this evening. Expect an increasing 
risk of large breaking waves, strong rip currents and sneaker 
waves through tonight. The hazard is for west to northwest facing
beaches where caution is advised. Northwest swell will subside 
late tonight into Saturday.

CAZ006-505-509-529-530-200500-
/O.CON.KMTR.BH.S.0006.000000T0000Z-210320T0600Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
153 PM PDT Fri Mar 19 2021

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

* WHAT...Northwest swell 13 to 15 feet at 15 seconds expected
  resulting in breaking waves of 18 to 24 feet.

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

* WHEN...From 10 AM PDT this morning to 10 PM PDT this evening.

* IMPACTS...Increasing risk of large breaking waves, strong rip 
  currents and sneaker waves.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
008 
WHUS46 KMTR 200453
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
953 PM PDT Fri Mar 19 2021


CAZ006-505-509-529-530-200600-
/O.EXT.KMTR.BH.S.0006.000000T0000Z-210320T0500Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
953 PM PDT Fri Mar 19 2021

...BEACH HAZARDS STATEMENT WILL EXPIRE AT 10 PM PDT THIS 
EVENING...

* Northwest swell will continue to subside this evening and no
  longer meets hazard criteria.

&&

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 19, 2:46 AM PDTSmall Craft AdvisoryMTR42 hr
Mar 19, 3:38 AM PDTAreal Flood AdvisoryMTRMonterey112 min

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.