Alert archive / California / Beach Hazards Statements in 2021

Beach Hazards Statement 8, NWS San Francisco Bay Area, CA

October 28, 20216 counties in California

NWS San Francisco Bay Area, CA issued this beach hazards statement at Oct 28, 2021, 8:37 AM PDT for 6 counties in California. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued
Oct 28, 2021, 8:37 AM PDT (15:37 UTC)
Expired
Oct 28, 2021, 6:00 PM PDT
In force
9 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 15:37 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, 3.6 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 2021-10-28Temperature 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 2021-10-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -37 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
1005 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-37 m²/s²
0-3 km storm-relative helicity
32 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

185 
WHUS46 KMTR 281537
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
837 AM PDT Thu Oct 28 2021

CAZ006-505-509-530-290100-
/O.NEW.KMTR.BH.S.0008.211028T1537Z-211029T0100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
837 AM PDT Thu Oct 28 2021

...BEACH HAZARDS STATEMENT IN EFFECT UNTIL 6 PM PDT THIS
EVENING...

* WHAT...Northwest swell 10 to 15 feet at 15 to 17 seconds. Large
  breaking waves of 15 to 20 feet. Increased risk of strong rip 
  currents and longshore currents.  

* WHERE...Northwest to west facing beaches of coastal North Bay,
  San Francisco, the San Francisco Peninsula to Davenport, 
  Southern Monterey Bay, Big Sur coast. 

* WHEN... through 6 PM this evening.

* IMPACTS...Increased risk of moderate to large breaking waves, 
  strong rip currents, and wave run up.

* ADDITIONAL DETAILS...Buoy observations indicate wave energy is
  outperforming model expectations. Main threats are breaking
  waves of 15 to 20 feet at northwest to west facing beaches and
  increased risk of rip and longshore currents. Wave energy is 
  expected to peak through the mid morning before tapering off 
  through the afternoon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Beach Hazard Statement means the potentially dangerous
conditions may exist on specific beaches. These hazards may
include large shore break...strong rip currents...strong longshore
currents and possibly sneaker waves. All of which could be life
threatening. Be sure to always keep your eyes on the ocean.

&&

$$
1 follow-up statement
410 
WHUS46 KMTR 290040
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
540 PM PDT Thu Oct 28 2021


CAZ006-505-509-530-290145-
/O.EXP.KMTR.BH.S.0008.000000T0000Z-211029T0100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
540 PM PDT Thu Oct 28 2021

...BEACH HAZARDS STATEMENT WILL EXPIRE AT 6 PM PDT THIS EVENING...

Significant wave heights and wave periods continuing to decrease
below beach hazards criteria tonight and Friday, the beach hazards
statement will be allowed to expire at 6 pm.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 28, 2:32 AM PDTSmall Craft AdvisoryMTR42 hr

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.