Alert archive / California / Freeze Watches in 2012

Freeze Watch 1, NWS San Francisco Bay Area, CA

January 15, 201210 counties in California

NWS San Francisco Bay Area, CA issued this freeze watch at Jan 15, 2012, 8:08 PM PST for 10 counties in California. It took effect at Jan 16, 2012, 11:00 PM PST. It was in force for .

The area

The counties it named.

The facts

Issued: Jan 15, 2012, 8:08 PM PST (04:08 UTC)
In effect from: Jan 16, 2012, 11:00 PM PST
Expired: Jan 16, 2012, 3:19 AM PST
In force
Issued by: NWS San Francisco Bay Area, CA

Counties Alameda County, CA, Contra Costa County, CA, Marin County, CA, Monterey County, CA, Napa County, CA, San Benito County, CA, San Mateo County, CA, Santa Clara County, CA, Santa Cruz County, CA, Sonoma County, CA

The radar

The San Francisco radar (KMUX), 42 km from the middle of the area, began a volume at 04:13 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 28 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1068 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 47 m²/s²
0-3 km storm-relative helicity: 80 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this freeze watch 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 freeze watch went out at Jan 15, 3:46 PM PST, 4 hours 22 minutes earlier.

Area forecast discussion, Jan 15, 3:46 PM PST, 4 hours 22 minutes before

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Hazardous weather outlook, Jan 15, 4:24 AM PST, 15 hours 44 minutes before

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In the hours before

Special weather statement, Jan 15, 5:38 PM PST, 2 hours 30 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jan 15, 8:48 PM PST	Small Craft Advisory for Rough Bar	MTR		6 hr
Jan 16, 3:19 AM PST	Freeze Watch	MTR	Monterey	24 hr
Jan 16, 3:19 AM PST	Freeze Warning	MTR	Alameda, Contra Costa, Marin, Monterey, Napa, San Benito and 4 more	29 hr

Nearby

Freeze Watches in California, 2012 Every freeze watch in 2012

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.