Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 53, NWS San Francisco Bay Area, CA

February 20, 2017Monterey County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Feb 20, 2017, 4:23 AM PST for Monterey County, California. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Feb 20, 2017, 4:23 AM PST (12:23 UTC)
Expired
Feb 20, 2017, 7:15 AM PST
In force
3 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Flood severity
None

County Monterey County, CA

The radar

The San Francisco radar (KMUX), 91 km from the middle of the area, began a volume at 12:24 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.

What was reported inside it

TimeReportWhereRemark
Feb 20, 6:50 AM PSTHEAVY RAIN 1.374 Se Big Sur Village, CA1.37 IN/HR FROM 530AM 630AM PST.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 0.4 hours before the alert went out and 160 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 2017-02-20Temperature 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 2017-02-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 364 square meters per square second.1939587897117136Sfc1 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
515 m above ground
0-6 km bulk shear
75 kt
0-1 km storm-relative helicity
364 m²/s²
0-3 km storm-relative helicity
367 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

405 
WGUS56 KMTR 201223
FFWMTR
CAC053-201515-
/O.NEW.KMTR.FF.W.0053.170220T1223Z-170220T1515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
423 AM PST MON FEB 20 2017

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

* Flash Flood Warning for the Soberanes Burn Area in...
  West central Monterey County in central California...

* Until 715 AM PST
    
* At 419 AM PST, Doppler radar and automated rain gauges indicated
  that heavy rain was falling over the area. Flash flooding is
  potentially occurring or is expected to begin shortly as additional
  heavy rainfall moves across the warned area this morning.

  This is a life threatening situation. Anyone living or traveling 
  on roads in the Soberanes Fire burn area or along secondary roads 
  and fire breaks...especially more well-traveled routes such as 
  Highway 1...Palo Colorado Road...and Old Coast Road...should be 
  alert for probable road problems due to erosion...debris 
  flows...rockfalls and debris. 

  Additional areas of concern include the Big Sur Area...Palo 
  Colorado Canyon...Parington Ridge...Tassajara Hot Springs and 
  dispersed coastal properties along Highway 1 south of Carmel 
  Highlands. Much of this terrain is extremely steep and contains 
  areas of moderate to high burn severity. Enhanced runoff and 
  erosion is likely and debris flows are possible. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Warning for a burn area means that flash flooding,
debris flows and or rock slides are likely or already occurring. If
you are in or near the warned area, you should seek a safe location
immediately. Your life may depend on how quickly you react.

&&

LAT...LON 3652 12190 3644 12175 3645 12171 3628 12144
      3625 12149 3625 12158 3618 12148 3614 12159
      3631 12190 3649 12195

$$

RGass

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 20, 3:53 AM PSTRiver Flood WarningMTRSanta Clara59 hr
Feb 20, 5:03 AM PSTRiver Flood WarningMTRMonterey29 hr
Feb 20, 7:07 AM PSTFlash Flood WarningMTRMonterey6 hr
Feb 20, 7:35 AM PSTAreal Flood AdvisoryMTRMarin, Napa, City and County of San Francisco, San Mateo, Sonoma3 hr
Feb 20, 7:40 AM PSTFlash Flood WarningMTRSanta Cruz6 hr
Feb 20, 7:44 AM PSTAreal Flood AdvisoryMTRSan Mateo, Santa Clara, Santa Cruz3 hr
Feb 20, 8:14 AM PSTFlash Flood WarningMTRMarin, Sonoma4 hr
Feb 20, 8:22 AM PSTAreal Flood WarningMTRSonoma60 hr
Feb 20, 8:56 AM PSTFlash Flood WarningMTRSan Benito6 hr
Feb 20, 9:04 AM PSTFlash Flood WarningMTRSanta Cruz6 hr
Feb 20, 10:13 AM PSTFlash Flood WarningMTRSan Benito, Santa Clara6 hr
Feb 20, 10:26 AM PSTFlash Flood WarningMTRAlameda6 hr
Feb 20, 10:34 AM PSTAreal Flood AdvisoryMTRMarin, Napa, City and County of San Francisco, San Mateo, Sonoma3 hr
Feb 20, 10:48 AM PSTAreal Flood AdvisoryMTRSan Mateo, Santa Clara, Santa Cruz3 hr
Feb 20, 11:21 AM PSTAreal Flood AdvisoryMTRAlameda, Contra Costa, Santa Clara3 hr
Feb 20, 1:32 PM PSTAreal Flood AdvisoryMTRMarin, Napa, City and County of San Francisco, San Mateo, Sonoma3 hr
Feb 20, 1:48 PM PSTAreal Flood AdvisoryMTRSan Mateo, Santa Clara, Santa Cruz3 hr
Feb 20, 2:14 PM PSTAreal Flood AdvisoryMTRMonterey4 hr
Feb 20, 2:24 PM PSTSmall Craft AdvisoryMTR18 hr
Feb 20, 2:40 PM PSTAreal Flood AdvisoryMTRSan Mateo65 min
Feb 20, 3:23 PM PSTAreal Flood WarningMTRSanta Clara6 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.