Alert archive / California / Flash Flood Watches in 2015

Flash Flood Watch 1, NWS San Francisco Bay Area, CA

February 4, 2015Marin County, Napa County, Sonoma County, California

NWS San Francisco Bay Area, CA issued this flash flood watch at Feb 4, 2015, 2:59 AM PST for Marin County, Napa County, Sonoma County, California. It took effect at Feb 5, 2015, 10:00 PM PST. It was in force for 16 hr.

The area

The counties it named.

The facts

Issued: Feb 4, 2015, 2:59 AM PST (10:59 UTC)
In effect from: Feb 5, 2015, 10:00 PM PST
Expired: Feb 6, 2015, 1:54 PM PST
In force: 16 hr
Issued by: NWS San Francisco Bay Area, CA
Flood severity: None

Counties Marin County, CA, Napa County, CA, Sonoma County, CA

The radar

The Sacramento radar (KDAX), 88 km from the middle of the area, began a volume at 10:58 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

Reno, NV (KREV), launched 00:00Z, 11.0 hours before the alert went out and 409 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: 2199 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 41 m²/s²
0-3 km storm-relative helicity: 78 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 flash flood 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 flash flood watch went out at Feb 3, 11:06 PM PST, 3 hours 53 minutes earlier.

Area forecast discussion, Feb 3, 11:06 PM PST, 3 hours 53 minutes before

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Hazardous weather outlook, Feb 3, 5:18 AM PST, 21 hours 41 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
Feb 4, 3:49 AM PST	Gale Watch	MTR		23 hr
Feb 4, 1:21 PM PST	Wind Advisory	MTR	Alameda, Contra Costa, Marin, Monterey, Napa, San Benito and 5 more	61 hr

Nearby

Flash Flood Watches in California, 2015 Every flash flood watch in 2015

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.