Alert archive / California / Extreme Cold Warnings in 2026

Extreme Cold Warning 4, NWS San Francisco Bay Area, CA

February 17, 2026Monterey County, San Benito County, Santa Clara County, California

NWS San Francisco Bay Area, CA issued this extreme cold warning at Feb 17, 2026, 2:59 AM PST for Monterey County, San Benito County, Santa Clara County, California. It took effect at Feb 18, 2026, 12:00 AM PST. It was in force for 9 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Feb 17, 2026, 2:59 AM PST (10:59 UTC)
In effect from
Feb 18, 2026, 12:00 AM PST
Expired
Feb 18, 2026, 9:00 AM PST
In force
9 hr
Issued by
NWS San Francisco Bay Area, CA

Counties Monterey County, CA, San Benito County, CA, Santa Clara County, CA

The radar

The San Francisco radar (KMUX), 70 km from the middle of the area, began a volume at 11:00 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, 11.0 hours before the alert went out and 232 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 2026-02-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 134 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Vandenberg AFB, CA at 00:00Z on 2026-02-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -35 square meters per square second.1939587897117Sfc1 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
134 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
542 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
-35 m²/s²
0-3 km storm-relative helicity
-3 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.4

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this extreme cold warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS San Francisco Bay Area, CA wrote its last area forecast discussion before this extreme cold warning went out at Feb 16, 10:01 PM PST, 4 hours 58 minutes earlier.

Area forecast discussion, Feb 16, 10:01 PM PST, 4 hours 58 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Feb 16, 8:32 PM PSTGale WarningMTR36 hr
Feb 17, 2:56 AM PSTCold Weather AdvisoryMTRMarin, Monterey, Napa, San Mateo, Santa Clara, Santa Cruz and 1 more30 hr
Feb 17, 7:10 AM PSTAreal Flood AdvisoryMTRMarin, Napa, Sonoma3 hr
Feb 17, 8:26 AM PSTSpecial Weather StatementMTRContra Costa34 min
Feb 17, 9:53 AM PSTAreal Flood AdvisoryMTRAlameda, Contra Costa, City and County of San Francisco, San Mateo, Santa Clara, Santa Cruz9 hr
Feb 17, 11:08 AM PSTSpecial Weather StatementMTRSanta Clara52 min
Feb 17, 1:18 PM PSTSpecial Weather StatementMTRMonterey27 min
Feb 17, 1:30 PM PSTAreal Flood AdvisoryMTRMonterey7 hr
Feb 17, 1:50 PM PSTSpecial Weather StatementMTRMonterey25 min
Feb 17, 2:14 PM PSTSpecial Weather StatementMTRMonterey31 min
Feb 17, 2:30 PM PSTSpecial Marine WarningMTR30 min
Feb 17, 2:42 PM PSTSpecial Weather StatementMTRMonterey33 min

Nearby

Extreme Cold Warnings in California, 2026Every extreme cold warning in 2026

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.