Alert archive / California / Flash Flood Warnings in 2016

Flash Flood Warning 19, NWS San Francisco Bay Area, CA

December 15, 2016Marin County, Sonoma County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Dec 15, 2016, 5:08 PM PST for Marin County, Sonoma County, California. It was in force for 3 hr. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Dec 15, 2016, 5:08 PM PST (01:08 UTC)
Expired
Dec 15, 2016, 8:00 PM PST
In force
3 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Flood severity
None

Counties Marin County, CA, Sonoma County, CA

The radar

The Sacramento radar (KDAX), 91 km from the middle of the area, began a volume at 01:11 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.

What was reported inside it

TimeReportWhereRemark
Dec 15, 6:59 PM PSTFLASH FLOOD1 S Sonoma, CA500 FEET OF ROADWAY FLOODING - AT LEAST 6 VEHICLES STALLED IN THE FLOODED ROAD
Dec 15, 7:49 PM PSTFLASH FLOOD2 W Rohnert Park, CAUP TO 4 FOOT HIGH WATER ON ROADWAY. SMALL VEHICLES STUCK IN FLOOD WATERS NR ROHNERT PARK EXPRESSWAY / STONY POINT RD

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Oakland, CA (KOAK), launched 00:00Z, 1.1 hours before the alert went out and 84 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 00:00Z on 2016-12-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3 joules per kilogram.LCLEL10008507005003002001001 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 00:00Z on 2016-12-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 336 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
3 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
436 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
336 m²/s²
0-3 km storm-relative helicity
481 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

920 
WGUS56 KMTR 160108
FFWMTR
CAC041-097-160400-
/O.NEW.KMTR.FF.W.0019.161216T0108Z-161216T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
508 PM PST THU DEC 15 2016

The National Weather Service in The San Francisco Bay Area has issued
a

* Flash Flood Warning for...
  Southeastern Sonoma County in northern California...
  Northern Marin County in northern California...

* Until 800 PM PST

* At 503 PM PST, although rain gauge reports indicate that much of
  the intense rainfall across the warned area has passed, creek
  gauges continue to show rising stages or creek levels remaining
  above flood stages at many locations. 

Automated stream gages have reported water levels remaining above
flood stage in Petaluma area creeks, Sonoma Creek at Agua Caliente,
and in the lower Laguna de Santa Rosa. There have also been reports
of flooding in other lowland valley settings in southern Sonoma
County and northern Marin County, as well as roadway flooding.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3857 12264 3839 12247 3816 12240 3813 12249
      3816 12272 3825 12297 3837 12307 3848 12290
      3856 12282

$$
 
MWS
1 follow-up statement
299 
WGUS76 KMTR 160357
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
757 PM PST THU DEC 15 2016

CAC041-097-160407-
/O.EXP.KMTR.FF.W.0019.000000T0000Z-161216T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sonoma CA-Marin CA-
757 PM PST THU DEC 15 2016

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN SONOMA AND NORTHERN MARIN
COUNTIES WILL EXPIRE AT 800 PM PST...

Flooding is no longer expected to pose a threat. Please continue to
heed any remaining road closures.

LAT...LON 3857 12264 3839 12247 3816 12240 3813 12249
      3816 12272 3825 12297 3837 12307 3848 12290
      3856 12282

$$

rww

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 15, 4:13 PM PSTFlash Flood WarningMTRMarin3 hr
Dec 15, 4:16 PM PSTAreal Flood AdvisoryMTRMarin, Napa, Sonoma3 hr
Dec 15, 4:58 PM PSTAreal Flood AdvisoryMTRSanta Clara, Santa Cruz4 hr
Dec 15, 5:27 PM PSTAreal Flood AdvisoryMTRSan Mateo, Santa Cruz3 hr
Dec 15, 5:29 PM PSTFlash Flood WarningMTRSanta Clara46 min
Dec 15, 5:46 PM PSTAreal Flood AdvisoryMTRAlameda, Contra Costa3 hr
Dec 15, 6:12 PM PSTFlash Flood WarningMTRSanta Clara3 hr
Dec 15, 6:16 PM PSTFlash Flood WarningMTRMonterey6 hr
Dec 15, 6:38 PM PSTFlash Flood WarningMTRSan Mateo, Santa Clara, Santa Cruz4 hr
Dec 15, 7:20 PM PSTAreal Flood AdvisoryMTRMonterey, San Benito3 hr
Dec 15, 9:02 PM PSTSmall Craft AdvisoryMTR48 hr
Dec 16, 2:43 AM PSTSmall Craft AdvisoryMTR18 hr
Dec 16, 7:14 AM PSTFrost AdvisoryMTRAlameda, Contra Costa, Monterey, San Mateo, Santa Clara, Santa Cruz25 hr
Dec 16, 7:14 AM PSTFrost AdvisoryMTRAlameda, Contra Costa, Marin, Monterey, City and County of San Francisco, San Mateo and 3 more49 hr
Dec 16, 7:14 AM PSTFreeze WarningMTRMarin, Napa, Sonoma25 hr
Dec 16, 7:14 AM PSTFreeze WarningMTRAlameda, Contra Costa, Marin, Monterey, Napa, San Benito and 4 more49 hr

Nearby

Flash Flood Warnings in California, 2016Every flash flood warning in 2016

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.