Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 30, NWS San Francisco Bay Area, CA

January 20, 2017San Benito County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Jan 20, 2017, 12:20 PM PST for San Benito County, California. It was in force for 4 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 20, 2017, 12:20 PM PST (20:20 UTC)
Expired
Jan 20, 2017, 4:15 PM PST
In force
4 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Flood severity
None

County San Benito County, CA

The radar

The San Francisco radar (KMUX), 48 km from the middle of the area, began a volume at 20:23 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, 8.3 hours before the alert went out and 111 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 2017-01-20Temperature 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 12:00Z on 2017-01-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 501 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
774 m above ground
0-6 km bulk shear
73 kt
0-1 km storm-relative helicity
501 m²/s²
0-3 km storm-relative helicity
746 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

632 
WGUS56 KMTR 202020
FFWMTR
CAC069-210015-
/O.NEW.KMTR.FF.W.0030.170120T2020Z-170121T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
1220 PM PST FRI JAN 20 2017

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

* Flash Flood Warning for...
  Northwestern San Benito County in central California...

* Until 415 PM PST

* At 1217 PM PST, gauge reports indicated water levels rising above
  12 feet at the Pacheco Creek near Dunneville stream gage,
  suggesting that active flooding may be occurring at this location
  and downstream in the northern Hollister area, as well as Soap
  Lake, San Felipe Lake, and Frazier lake area. Flash flooding is
  already occurring.

* Some locations that will experience flooding include...
  ranchland and rural residential areas north of Hollister.

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 3685 12134 3688 12146 3689 12157 3691 12156
      3695 12151 3696 12151 3698 12149 3698 12147
      3699 12146 3699 12145 3696 12142 3696 12126
      3695 12126

$$

MWS
1 follow-up statement
235 
WGUS76 KMTR 210003
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
403 PM PST FRI JAN 20 2017

CAC069-210010-
/O.CAN.KMTR.FF.W.0030.000000T0000Z-170121T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Benito CA-
403 PM PST FRI JAN 20 2017

...THE FLASH FLOOD WARNING FOR NORTHWESTERN SAN BENITO COUNTY IS
CANCELLED...

The heavy rain has ended. Flooding is continuing in the lower
Pacheco Creek area near Soap/San Felipe Lake and Frazier Lake north
of Hollister.  An Areal Flood Warning has just been issued to warn
for the prolonged and ongoing flooding in the area.

LAT...LON 3685 12134 3688 12146 3689 12157 3691 12156
      3695 12151 3696 12151 3698 12149 3698 12147
      3699 12146 3699 12145 3696 12142 3696 12126
      3695 12126

$$

MWS

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 19, 9:01 PM PSTGale WarningMTR10 hr
Jan 19, 9:01 PM PSTSmall Craft AdvisoryMTR42 hr
Jan 20, 1:26 AM PSTAreal Flood AdvisoryMTRMarin, Sonoma3 hr
Jan 20, 3:02 AM PSTSpecial Marine WarningMTR43 min
Jan 20, 3:39 AM PSTSpecial Weather StatementMTRSan Mateo36 min
Jan 20, 4:07 AM PSTSpecial Marine WarningMTR23 min
Jan 20, 4:14 AM PSTSpecial Weather StatementMTRAlameda, Contra Costa, San Mateo31 min
Jan 20, 4:49 AM PSTFlash Flood WarningMTRSonoma4 hr
Jan 20, 5:27 AM PSTAreal Flood AdvisoryMTRSan Mateo, Santa Clara, Santa Cruz3 hr
Jan 20, 6:38 AM PSTFlash Flood WarningMTRSanta Cruz6 hr
Jan 20, 7:08 AM PSTFlash Flood WarningMTRSanta Clara6 hr
Jan 20, 7:31 AM PSTAreal Flood WarningMTRSanta Cruz12 hr
Jan 20, 7:55 AM PSTAreal Flood WarningMTRSonoma18 hr
Jan 20, 12:51 PM PSTHigh Wind WatchMTRAlameda, Contra Costa, Marin, Monterey, Napa, San Benito and 5 more15 hr
Jan 20, 1:27 PM PSTFlash Flood WatchMTRAlameda, Contra Costa, Marin, Monterey, Napa, San Benito and 5 more3 days
Jan 20, 2:33 PM PSTGale WatchMTR14 hr
Jan 20, 2:33 PM PSTGale WarningMTR42 hr
Jan 20, 3:51 PM PSTAreal Flood AdvisoryMTRSan Benito, Santa Clara70 hr
Jan 20, 3:56 PM PSTAreal Flood WarningMTRSan Benito, Santa Clara72 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.