Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 1, NWS San Francisco Bay Area, CA

January 4, 2017Santa Cruz County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Jan 4, 2017, 1:08 AM PST for Santa Cruz 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
Jan 4, 2017, 1:08 AM PST (09:08 UTC)
Expired
Jan 4, 2017, 4:00 AM PST
In force
3 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Flood severity
None

County Santa Cruz County, CA

The radar

The San Francisco radar (KMUX), 20 km from the middle of the area, began a volume at 09:10 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, 9.1 hours before the alert went out and 78 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 2017-01-04Temperature 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 2017-01-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 335 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
707 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
335 m²/s²
0-3 km storm-relative helicity
696 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

208 
WGUS56 KMTR 040908
FFWMTR
CAC087-041200-
/O.NEW.KMTR.FF.W.0001.170104T0908Z-170104T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
108 AM PST WED JAN 4 2017

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

* Flash Flood Warning for...
  Central Santa Cruz County in northern California...

* Until 400 AM PST

* At 106 AM PST, Doppler radar indicated rain continuing across the
  warned area. The San Lorenzo River gauge at Big Trees has been
  rapidly rising and is quickly nearing flash flood levels. Flash
  flooding is expected to begin shortly.

* Some locations that will likely experience flooding include...
  Scotts Valley and Felton. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 3701 12206 3704 12210 3707 12207 3704 12203

$$
1 follow-up statement
687 
WGUS76 KMTR 041047
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
247 AM PST WED JAN 4 2017

CAC087-041200-
/O.CON.KMTR.FF.W.0001.000000T0000Z-170104T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Santa Cruz CA-
247 AM PST WED JAN 4 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 AM PST FOR
CENTRAL SANTA CRUZ COUNTY...

At 244 AM PST, Doppler radar indicated rain continuing across the
San Lorenzo River at Big Trees with additional rainfall likely.  In
addition, the gauge has gone over flood stage several times over the
past two hours. 

Some locations that will may flooding include...
Scotts Valley and Felton. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 3701 12206 3704 12210 3707 12207 3704 12203

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 3, 5:31 PM PSTAreal Flood WarningMTRAlameda, Contra Costa, Marin, Monterey, Napa, San Benito and 5 more6 hr
Jan 3, 5:43 PM PSTAreal Flood AdvisoryMTRAlameda, Contra Costa, Marin, Monterey, Napa, San Benito and 5 more12 hr
Jan 4, 2:35 AM PSTSmall Craft AdvisoryMTR6 hr
Jan 4, 3:41 AM PSTFlash Flood WarningMTRSonoma4 hr
Jan 4, 3:53 AM PSTFlash Flood WarningMTRSanta Cruz3 hr
Jan 4, 4:40 AM PSTFlash Flood WarningMTRMonterey6 hr
Jan 4, 3:30 PM PSTFlash Flood WarningMTRSanta Clara2 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.