Alert archive / California / Flash Flood Watches in 2018
Flash Flood Watch 1, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this flash flood watch at Jan 7, 2018, 4:06 AM PST for Marin County, Napa County, Sonoma County, California. It took effect at Jan 8, 2018, 12:00 PM PST. It was in force for 13 hr.
The area
The counties it named.
The facts
- Issued
- Jan 7, 2018, 4:06 AM PST (12:06 UTC)
- In effect from
- Jan 8, 2018, 12:00 PM PST
- Expired
- Jan 9, 2018, 1:23 AM PST
- In force
- 13 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 12:03 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 12:00Z, 0.1 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1642 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- -13 m²/s²
- 0-3 km storm-relative helicity
- 55 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 Jan 7, 3:53 AM PST, 13 minutes earlier.
Area forecast discussion, Jan 7, 3:53 AM PST, 13 minutes before
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</html>Hazardous weather outlook, Jan 6, 7:26 PM PST, 8 hours 40 minutes before
Hazardous Weather Outlook National Weather Service San Francisco CA 726 PM PST Sat Jan 6 2018 CAZ006-505>513-516>518-528>530-071400- San Francisco- Coastal North Bay Including Point Reyes National Seashore- North Bay Interior Valleys-North Bay Mountains- San Francisco Bay Shoreline-San Francisco Peninsula Coast- East Bay Interior Valleys-East Bay Hills and the Diablo Range- Santa Cruz Mountains-Santa Clara Valley Including San Jose- Southern Salinas Valley/Arroyo Seco and Lake San Antonio- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- Northern Salinas Valley/Hollister Valley and Carmel Valley- Northern Monterey Bay-Southern Monterey Bay and Big Sur Coast- 726 PM PST Sat Jan 6 2018 This Hazardous Weather Outlook is for the San Francisco Bay Area and Monterey Bay Area. .DAY ONE...Saturday Night Partly cloudy skies and mild temperatures are forecast for Saturday night. Patchy fog will likely develop late in the North Bay Valleys, East Bay Valleys, and around San Francisco Bay. Patchy dense fog is possible in the North Bay Valleys and near the Delta. .DAYS TWO THROUGH SEVEN...Sunday through Friday Patchy fog will continue into Sunday morning. A wet and windy storm system is expected to impact the region from late Sunday night through Tuesday. * Precipitation onset: Rain is forecast to spread across the region late Sunday night and Monday morning. * Precipitation duration: Periods of rain will then continue through Monday afternoon and Monday night. Scattered showers are forecast for Tuesday and possibly into Tuesday night. * Precipitation intensity: Locally heavy rain is possible from midday Monday through Monday night. Heavy rain over the North Bay burn scars may result in debris flows. * Thunderstorm potential: There is a slight chance of thunderstorms across the southern portion of the forecast area on Tuesday afternoon and evening. * Forecast rainfall amounts (Late Sunday night through Tuesday evening): Coastal Mountains: 3-5 inches, Inland Mountains: 2-3", Coastal plains and most valleys: 1-2.5", Rain-sheltered valleys: 0.5-1.0" * Winds: Strong and gusty southerly winds will develop on Monday morning and persist through Monday night. Wind gusts of between 40 and 55 mph are possible, especially near the coast and at higher elevations. Wind advisories may be issued.
The office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jan 7, 2:44 AM PST | Gale Watch | MTR | 12 hr | |
| Jan 7, 2:44 AM PST | Small Craft Advisory | MTR | 4 days | |
| Jan 7, 4:33 AM PST | High Wind Warning | MTR | Monterey | 47 hr |
| Jan 7, 4:33 AM PST | Wind Advisory | MTR | Alameda, Contra Costa, Marin, Monterey, San Benito, City and County of San Francisco and 4 more | 46 hr |
| Jan 7, 2:32 PM PST | Gale Warning | MTR | 36 hr |
Nearby
Flash Flood Watches in California, 2018Every flash flood watch in 2018
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.