Alert archive / California / Wind Advisories in 2021

Wind Advisory 8, NWS San Francisco Bay Area, CA

May 20, 20216 counties in California

NWS San Francisco Bay Area, CA issued this wind advisory at May 20, 2021, 11:10 AM PDT for 6 counties in California. It took effect at May 20, 2021, 2:00 PM PDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
May 20, 2021, 11:10 AM PDT (18:10 UTC)
In effect from
May 20, 2021, 2:00 PM PDT
Expired
May 20, 2021, 9:00 PM PDT
In force
7 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 18:14 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, 6.2 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 2021-05-20Temperature 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 2021-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -48 square meters per square second.1939587897Sfc1 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
1206 m above ground
0-6 km bulk shear
63 kt
0-1 km storm-relative helicity
-48 m²/s²
0-3 km storm-relative helicity
5 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

878 
WWUS76 KMTR 201810
NPWMTR

URGENT - WEATHER MESSAGE
National Weather Service San Francisco Bay Area
1110 AM PDT Thu May 20 2021

CAZ006-505-509-530-210400-
/O.NEW.KMTR.WI.Y.0008.210520T2100Z-210521T0400Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
Including the cities of San Francisco, Tamalpais-Homestead, 
Sausalito, Pacifica, Seaside, Monterey, and Marina
1110 AM PDT Thu May 20 2021

...WIND ADVISORY IN EFFECT UNTIL 9 PM PDT THIS EVENING...

* WHAT...Northwest winds 20 to 30 mph with gusts up to 50 mph 
  expected.

* WHERE...San Francisco, Coastal North Bay Including Point Reyes
  National Seashore, San Francisco Peninsula Coast and Southern
  Monterey Bay and Big Sur Coast. Strongest near the beaches and
  along immediate coastline.

* WHEN...Until 9 PM PDT this evening.

* IMPACTS...Gusty winds this strong could cause blowing sand
  across roadways and beaches, blow around unsecured objects and 
  make driving difficult, especially for high profile vehicles. 
  This includes Highway 1.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use extra caution when driving, especially if operating a high
profile vehicle. Secure outdoor objects.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/BayArea

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 2:56 AM PDTSmall Craft AdvisoryMTR14 hr

Nearby

Wind Advisories in California, 2021Every wind advisory 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.