Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 48, NWS San Francisco Bay Area, CA

February 9, 2017Marin County, Sonoma County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Feb 9, 2017, 11:41 AM PST for Marin County, Sonoma County, California. It was in force for 7 hr. 1 report 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
Feb 9, 2017, 11:41 AM PST (19:41 UTC)
Expired
Feb 9, 2017, 6:30 PM PST
In force
7 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), 85 km from the middle of the area, began a volume at 19:41 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
Feb 9, 2:42 PM PSTFLOOD5 Ese Petaluma, CALAKEVILLE HWY AT EMIES TIN BAR...WEST BOUND LANES COMPLETELY FLOODED AND EAST BOUND LANES PARTIALLY FLOODED

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 12:00Z, 7.7 hours before the alert went out and 66 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 12:00Z on 2017-02-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 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 12:00Z on 2017-02-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 182 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
2 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
838 m above ground
0-6 km bulk shear
66 kt
0-1 km storm-relative helicity
182 m²/s²
0-3 km storm-relative helicity
353 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

049 
WGUS56 KMTR 091941
FFWMTR
CAC041-097-100130-
/O.NEW.KMTR.FF.W.0048.170209T1941Z-170210T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
1141 AM PST THU FEB 9 2017

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

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

* Until 530 PM PST

* At 1133 AM PST, stream gage reports indicated accelerated runoff
  entering the Petaluma basin in response to this morning's
  continued rainfall. Water levels on Willow Brook at Penngrove Park
  are rising rapidly and are approaching flood stage. Flash flooding
  is expected to begin shortly.

* Some locations that will experience flooding include...
  Petaluma, Penngrove.

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 3832 12259 3824 12254 3812 12247 3811 12249
      3818 12255 3820 12262 3825 12270 3829 12270
      3831 12266

$$

MWS
1 follow-up statement
709 
WGUS56 KMTR 100130
FFWMTR
CAC041-097-100230-
/O.EXT.KMTR.FF.W.0048.000000T0000Z-170210T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
530 PM PST THU FEB 9 2017

The National Weather Service in The San Francisco Bay Area has
extended the

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

* Until 630 PM PST

* At 500 PM PST, stream gage reports indicated continued flooding in
  the Petaluma basin due to rainfall earlier today. The stream gage
  on Willow Brook at Penngrove Park was still above flood stage,
  although water levels were beginning to recede.

* Some locations that will experience flooding include...
  Petaluma, Penngrove.

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 3832 12259 3824 12254 3812 12247 3811 12249
      3818 12255 3820 12262 3825 12270 3829 12270
      3831 12266

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 9, 2:20 AM PSTSmall Craft Advisory for Rough BarMTR19 hr
Feb 9, 4:10 AM PSTRiver Flood WarningMTRNapa24 hr
Feb 9, 12:15 PM PSTFlash Flood WarningMTRMarin6 hr
Feb 9, 12:27 PM PSTFlash Flood WarningMTRSonoma6 hr
Feb 9, 12:40 PM PSTFlash Flood WarningMTRSonoma5 hr
Feb 9, 1:21 PM PSTFlash Flood WarningMTRNapa5 hr
Feb 9, 3:04 PM PSTSmall Craft AdvisoryMTR71 hr
Feb 9, 3:36 PM PSTRiver Flood WarningMTRNapa23 hr

Nearby

Flash Flood Warnings in California, 2017Every flash flood warning in 2017

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.