Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 50, NWS San Francisco Bay Area, CA

February 9, 2017Sonoma County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Feb 9, 2017, 12:27 PM PST for Sonoma County, California. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Feb 9, 2017, 12:27 PM PST (20:27 UTC)
Expired
Feb 9, 2017, 6:30 PM PST
In force
6 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Flood severity
None

County Sonoma County, CA

The radar

The Sacramento radar (KDAX), 74 km from the middle of the area, began a volume at 20:29 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 12:00Z, 8.5 hours before the alert went out and 61 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.

421 
WGUS56 KMTR 092027
FFWMTR
CAC097-100230-
/O.NEW.KMTR.FF.W.0050.170209T2027Z-170210T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
1227 PM 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...

* Until 630 PM PST Thursday

* At 1226 PM PST, Heavy rain has been falling across the warning
  area for much of the morning, and stream gages on Sonoma Creek are
  rapidly rising above flood stages. Flash flooding is already
  occurring or is imminent.

* Some locations that will experience flooding include...
  Sonoma, Boyes Hot Springs, Glen Ellen, Fetters Hot Springs-Agua
  Caliente, Eldridge, Temelec, and El Verano.

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 3838 12250 3833 12247 3830 12242 3823 12237
      3817 12237 3816 12242 3813 12243 3812 12246
      3817 12248 3819 12245 3820 12245 3826 12251
      3837 12256

$$

MWS
1 follow-up statement
266 
WGUS76 KMTR 100229
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
629 PM PST THU FEB 9 2017

CAC097-100237-
/O.EXP.KMTR.FF.W.0050.000000T0000Z-170210T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sonoma CA-
629 PM PST THU FEB 9 2017

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN SONOMA COUNTY WILL EXPIRE
AT 630 PM PST THURSDAY...

Rainfall in the area ended hours ago and stream gages on the Sonoma
Creek indicate the creek has receded and is back in its banks, or
will be shortly. Therefore, the flash flood warning for southeastern
Sonoma County will be allowed to expire at 6:30 PM PST. Please
continue to heed all road closures.

LAT...LON 3838 12250 3833 12247 3830 12242 3823 12237
      3817 12237 3816 12242 3813 12243 3812 12246
      3817 12248 3819 12245 3820 12245 3826 12251
      3837 12256

$$

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, 11:41 AM PSTFlash Flood WarningMTRMarin, Sonoma7 hr
Feb 9, 12:15 PM PSTFlash Flood WarningMTRMarin6 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.