Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 47, NWS San Francisco Bay Area, CA

February 7, 2017Alameda County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Feb 7, 2017, 5:27 PM PST for Alameda County, California. It was in force for 2 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, 5:27 PM PST (01:27 UTC)
Expired
Feb 7, 2017, 7:30 PM PST
In force
2 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Flood severity
None

County Alameda County, CA

The radar

The San Francisco radar (KMUX), 45 km from the middle of the area, began a volume at 01:31 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 00:00Z, 1.5 hours before the alert went out and 33 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 2017-02-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2017-02-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 131 square meters per square second.1939587897117Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
625 m above ground
0-6 km bulk shear
77 kt
0-1 km storm-relative helicity
131 m²/s²
0-3 km storm-relative helicity
237 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

569 
WGUS56 KMTR 080127
FFWMTR
CAC001-080330-
/O.NEW.KMTR.FF.W.0047.170208T0127Z-170208T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

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

* Flash Flood Warning for...
  South central Alameda County in northern California...

* Until 730 PM PST

* At 524 PM PST, the automated gauge at Alameda Creek near Niles is
  receding, but remains near flood stage. The flash flood warning
  has been extended through 7:30 pm PST.

Mud slides are still possible this evening, mud slides 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 3759 12187 3754 12184 3752 12182 3751 12179
      3749 12174 3749 12177 3750 12181 3750 12183
      3753 12186 3757 12188 3759 12191 3758 12194
      3757 12196 3756 12199 3757 12203 3759 12202
      3758 12200 3758 12198 3761 12195 3761 12190

$$
1 follow-up statement
862 
WGUS76 KMTR 080324
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
724 PM PST TUE FEB 7 2017

CAC001-080333-
/O.EXP.KMTR.FF.W.0047.000000T0000Z-170208T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Alameda CA-
724 PM PST TUE FEB 7 2017

...THE FLASH FLOOD WARNING FOR SOUTH CENTRAL ALAMEDA COUNTY WILL
EXPIRE AT 730 PM PST...

Flooding is no longer expected to pose a threat. The river level is
falling quickly and should be below flood stage shortly. Please
continue to heed any remaining road closures.

LAT...LON 3759 12187 3754 12184 3752 12182 3751 12179
      3749 12174 3749 12177 3750 12181 3750 12183
      3753 12186 3757 12188 3759 12191 3758 12194
      3757 12196 3756 12199 3757 12203 3759 12202
      3758 12200 3758 12198 3761 12195 3761 12190

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 7, 5:13 PM PSTAreal Flood WarningMTRMonterey6 hr
Feb 8, 1:57 AM PSTWind AdvisoryMTRMarin, Napa, San Mateo, Santa Clara, Santa Cruz, Sonoma38 hr
Feb 8, 2:23 AM PSTSmall Craft AdvisoryMTR43 hr
Feb 8, 8:37 AM PSTAreal Flood WarningMTRSonoma4 days
Feb 8, 9:18 AM PSTFlash Flood WatchMTRMarin, Monterey, Napa, San Mateo, Santa Clara, Santa Cruz and 1 more41 hr
Feb 8, 2:43 PM PSTCoastal Flood WarningMTRMarin, Monterey, City and County of San Francisco, San Mateo, Santa Cruz, Sonoma21 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.