Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 39, NWS San Francisco Bay Area, CA

February 7, 2017Napa County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Feb 7, 2017, 7:15 AM PST for Napa 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 7, 2017, 7:15 AM PST (15:15 UTC)
Expired
Feb 7, 2017, 1:15 PM PST
In force
6 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Flood severity
None

County Napa County, CA

The radar

The Sacramento radar (KDAX), 68 km from the middle of the area, began a volume at 15:19 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, 3.3 hours before the alert went out and 81 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 2017-02-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 66 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 12:00Z on 2017-02-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 518 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
66 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
653 m above ground
0-6 km bulk shear
77 kt
0-1 km storm-relative helicity
518 m²/s²
0-3 km storm-relative helicity
725 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

960 
WGUS56 KMTR 071515
FFWMTR
CAC055-072115-
/O.NEW.KMTR.FF.W.0039.170207T1515Z-170207T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
715 AM PST TUE FEB 7 2017

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

* Flash Flood Warning for...
  Southwestern Napa County in northern California...

* Until 115 PM PST Tuesday

* At 714 AM PST, stream gage reports indicated that flash flooding
  is already occurring or is imminent in many locations in the Napa
  Valley area.  Reports of flooded roads and mudslides are numerous.

* Some locations that will experience flooding include...
  Napa, St. Helena, Calistoga, Yountville, Deer Park, and other
  unincorporated areas of the County in Napa Valley. 

Excessive rainfall over the warned area will cause mud slides near
steep terrain. The mud slide can consist of rock, mud, vegetation and
other loose materials.

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 3865 12262 3853 12242 3839 12223 3826 12226
      3816 12227 3816 12233 3822 12234 3832 12240
      3843 12249 3845 12248 3847 12252 3851 12255
      3852 12254 3853 12256 3860 12262

$$

MWS
1 follow-up statement
019 
WGUS76 KMTR 071943
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
1143 AM PST TUE FEB 7 2017

CAC055-071951-
/O.CAN.KMTR.FF.W.0039.000000T0000Z-170207T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Napa CA-
1143 AM PST TUE FEB 7 2017

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN NAPA COUNTY IS
CANCELLED...

The heavy rain has ended. Flood waters are receding. Please 
continue to heed any remaining road closures.

LAT...LON 3865 12262 3853 12242 3839 12223 3826 12226
      3816 12227 3816 12233 3822 12234 3832 12240
      3843 12249 3845 12248 3847 12252 3851 12255
      3852 12254 3853 12256 3860 12262

$$

rww

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 7, 12:21 AM PSTAreal Flood WarningMTRSonoma32 hr
Feb 7, 1:03 AM PSTAreal Flood WarningMTRSonoma11 hr
Feb 7, 1:47 AM PSTAreal Flood WarningMTRNapa6 hr
Feb 7, 2:28 AM PSTAreal Flood AdvisoryMTRAlameda, Contra Costa2 hr
Feb 7, 7:09 AM PSTFlash Flood WarningMTRMarin4 hr
Feb 7, 7:34 AM PSTFlash Flood WarningMTRSanta Cruz8 hr
Feb 7, 9:33 AM PSTFlash Flood WarningMTRAlameda8 hr
Feb 7, 9:55 AM PSTFlash Flood WarningMTRSanta Clara8 hr
Feb 7, 10:22 AM PSTFlash Flood WarningMTRSan Benito, Santa Clara12 hr
Feb 7, 10:26 AM PSTAreal Flood WarningMTRSan Mateo11 hr
Feb 7, 10:47 AM PSTFlash Flood WarningMTRSan Mateo, Santa Clara3 hr
Feb 7, 11:04 AM PSTRiver Flood WarningMTRSonoma4 days
Feb 7, 11:30 AM PSTFlash Flood WarningMTRSanta Cruz6 hr
Feb 7, 11:59 AM PSTFlash Flood WarningMTRMonterey4 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.