Alert archive / California / Flash Flood Warnings in 2016

Flash Flood Warning 21, NWS San Francisco Bay Area, CA

December 15, 2016Santa Clara County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Dec 15, 2016, 6:12 PM PST for Santa Clara County, California. It was in force for 3 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
Dec 15, 2016, 6:12 PM PST (02:12 UTC)
Expired
Dec 15, 2016, 9:15 PM PST
In force
3 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Flood severity
None

County Santa Clara County, CA

The radar

The San Francisco radar (KMUX), 10 km from the middle of the area, began a volume at 02:13 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, 2.2 hours before the alert went out and 77 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°0°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.

147 
WGUS56 KMTR 160212
FFWMTR
CAC085-160515-
/O.NEW.KMTR.FF.W.0021.161216T0212Z-161216T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

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

* Flash Flood Warning for...
  Central Santa Clara County in northern California...including the 
  Loma Fire burn scar.

* Until 915 PM PST

* At 611 PM PST, Doppler radar and automated rain gauges indicated
  heavy rain falling across the warned area. Flash flooding is
  expected to begin shortly.

* Some locations that will experience flooding include...
  Uvas Canyon Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Move away from recently burned areas. Life-threatening flooding of
creeks, roads and normally dry arroyos is likely. The heavy rains
will likely trigger rockslides, mudslides and debris flows in steep
terrain, especially in and around these areas.

&&

LAT...LON 3715 12183 3715 12173 3709 12171 3708 12179
      3710 12185

$$

RWW
1 follow-up statement
337 
WGUS76 KMTR 160512
FFSMTR

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

CAC085-160521-
/O.EXP.KMTR.FF.W.0021.000000T0000Z-161216T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Santa Clara CA-
912 PM PST THU DEC 15 2016

...THE FLASH FLOOD WARNING FOR CENTRAL SANTA CLARA COUNTY WILL EXPIRE
AT 915 PM PST...

The heaviest rain has ended. Flood waters are receding. New flooding
is no longer expected to pose a threat. Please continue to heed any
remaining road closures.

LAT...LON 3715 12183 3715 12173 3709 12171 3708 12179
      3710 12185

$$

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, 5:08 PM PSTFlash Flood WarningMTRMarin, Sonoma3 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, 6:16 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.