Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 17, NWS San Francisco Bay Area, CA

January 10, 2017Napa County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Jan 10, 2017, 2:08 PM PST for Napa County, California. It was in force for 6 hr. 2 reports 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
Jan 10, 2017, 2:08 PM PST (22:08 UTC)
Expired
Jan 10, 2017, 8:00 PM PST
In force
6 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Flood severity
None

County Napa County, CA

The radar

The Sacramento radar (KDAX), 65 km from the middle of the area, began a volume at 22:12 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
Jan 10, 5:13 PM PSTFLOOD3 N Napa, CABIG RANCH RD COMPLETELY UNDER WATER AT SALVADOR AVE
Jan 10, 5:13 PM PSTFLOOD4 N Napa, CASILVERADO TRAIL FOODING AT TRANCAS ST

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, 10.1 hours before the alert went out and 74 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°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.

977 
WGUS56 KMTR 102208
FFWMTR
CAC055-110400-
/O.NEW.KMTR.FF.W.0017.170110T2208Z-170111T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

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

* Flash Flood Warning for...
  Southwestern Napa County in northern California...

* Until 800 PM PST

* At 205 PM PST, Doppler radar indicated heavy rain across the
  warned area. Most stream gaging sites in the area are indicating
  that water levels are quickly rising, and many sites have reached
  Monitor Stage.  Flash flooding is expected to begin shortly, and
  rainfall is expected to continue through the afternoon and evening
  hours.

* Some locations that will experience flooding include...
  Napa, American Canyon, St. Helena, Calistoga, Yountville, Deer Park
  and Angwin.

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 3849 12235 3842 12223 3816 12222 3816 12232
      3822 12236 3825 12237 3828 12240 3831 12240
      3833 12241 3837 12246 3838 12245 3843 12250
      3845 12248 3847 12253 3859 12259 3860 12248

$$

MWS
1 follow-up statement
753 
WGUS76 KMTR 110354
FFSMTR

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

CAC055-110400-
/O.EXP.KMTR.FF.W.0017.000000T0000Z-170111T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Napa CA-
754 PM PST TUE JAN 10 2017

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN NAPA COUNTY WILL EXPIRE
AT 800 PM PST...

At 7:50 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 3849 12235 3842 12223 3816 12222 3816 12232
      3822 12236 3825 12237 3828 12240 3831 12240
      3833 12241 3837 12246 3838 12245 3843 12250
      3845 12248 3847 12253 3859 12259 3860 12248

$$

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, 2:27 PM PSTFlash Flood WarningMTRMarin6 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.