Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 18, NWS San Francisco Bay Area, CA

January 10, 2017Marin County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Jan 10, 2017, 2:27 PM PST for Marin County, California. It was in force for 6 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 10, 2017, 2:27 PM PST (22:27 UTC)
Expired
Jan 10, 2017, 8:30 PM PST
In force
6 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Flood severity
None

County Marin County, CA

The radar

The Sacramento radar (KDAX), 96 km from the middle of the area, began a volume at 22:30 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, 10.5 hours before the alert went out and 40 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 2017-01-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 8 joules per kilogram.LCLLFCEL10008507005003002001001 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 12:00Z on 2017-01-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 191 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
8 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
604 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
191 m²/s²
0-3 km storm-relative helicity
263 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

405 
WGUS56 KMTR 102227
FFWMTR
CAC041-110430-
/O.NEW.KMTR.FF.W.0018.170110T2227Z-170111T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
227 PM PST TUE JAN 10 2017

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

* Flash Flood Warning for...
  East central Marin County in northern California...

* Until 830 PM PST Tuesday

* At 225 PM PST, Doppler radar and automated rain gauges indicated
  heavy rain falling across the Corte Madera Creek watershed.
  Automated stream gages in the watershed show rapidly rising water
  levels that have surpassed Monitor Stage and are quickly
  approaching Flood Stage.  Flash flooding is expected to begin
  shortly.

* Some locations that will experience flooding include...
  San Anselmo, Larkspur, Corte Madera, Fairfax, Kentfield and Ross.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

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 3797 12251 3790 12246 3792 12254 3797 12260
      3800 12261 3800 12257

$$

MWS
1 follow-up statement
171 
WGUS76 KMTR 110422
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
822 PM PST TUE JAN 10 2017

CAC041-110430-
/O.EXP.KMTR.FF.W.0018.000000T0000Z-170111T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Marin CA-
822 PM PST TUE JAN 10 2017

...THE FLASH FLOOD WARNING FOR EAST CENTRAL MARIN COUNTY WILL EXPIRE
AT 830 PM PST...

At 8:20 PM PST, heavy rainfall continues to diminish across the
region and the threat for flash flooding has ended. However, run-off
from recent rainfall continues to result in flooding of low lying
areas and an Areal Flood Warning will be posted for this threat.
Please continue to heed any remaining road closures.

LAT...LON 3797 12251 3790 12246 3792 12254 3797 12260
      3800 12261 3800 12257

$$

RGass

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 9, 9:10 PM PSTSmall Craft Advisory for Rough BarMTR24 hr
Jan 10, 2:25 AM PSTRiver Flood WarningMTRNapa25 hr
Jan 10, 2:25 AM PSTRiver Flood WarningMTRNapa31 hr
Jan 10, 8:38 AM PSTGale WarningMTR12 hr
Jan 10, 10:56 AM PSTAreal Flood WarningMTRSonoma48 hr
Jan 10, 11:29 AM PSTAreal Flood WarningMTRMonterey, Santa Cruz48 hr
Jan 10, 12:18 PM PSTFlash Flood WarningMTRSonoma6 hr
Jan 10, 12:40 PM PSTFlash Flood WarningMTRSanta Clara6 hr
Jan 10, 2:08 PM PSTFlash Flood WarningMTRNapa6 hr
Jan 10, 2:51 PM PSTAreal Flood WarningMTRSanta Clara36 hr
Jan 10, 2:55 PM PSTAreal Flood AdvisoryMTRSan Mateo, Santa Clara2 hr
Jan 10, 3:07 PM PSTSmall Craft AdvisoryMTR60 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.