Alert archive / California / Flash Flood Warnings in 2016

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

December 15, 2016Napa County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Dec 15, 2016, 3:38 PM PST for Napa 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
Dec 15, 2016, 3:38 PM PST (23:38 UTC)
Expired
Dec 15, 2016, 6:30 PM PST
In force
3 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), 59 km from the middle of the area, began a volume at 23:41 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, 11.6 hours before the alert went out and 70 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 2016-12-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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 2016-12-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 276 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
1 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
767 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
276 m²/s²
0-3 km storm-relative helicity
311 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

359 
WGUS56 KMTR 152338
FFWMTR
CAC055-160230-
/O.NEW.KMTR.FF.W.0017.161215T2338Z-161216T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
338 PM PST THU DEC 15 2016

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

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

* Until 630 PM PST

* At 335 PM PST, gauge reports indicated heavy rain falling across
  the warned area. Flash flooding is already occurring.

Flooding is already occurring or is expected to occur in many Napa
River tributary creeks and on the Napa River mainstem.  This Flash
Flood Warning supplements the previously issued Flood Warning for
the Napa River near St. Helena.

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 3834 12220 3827 12221 3827 12222 3826 12221
      3816 12222 3816 12233 3832 12238 3847 12247
      3860 12264 3868 12251

$$

MWS
2 follow-up statements
716 
WGUS76 KMTR 160059
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
459 PM PST THU DEC 15 2016

CAC055-160230-
/O.CON.KMTR.FF.W.0017.000000T0000Z-161216T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Napa CA-
459 PM PST THU DEC 15 2016

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM PST FOR
SOUTHWESTERN NAPA COUNTY...

At 458 PM PST, gauge reports indicated that heavy rain was falling
over the warned area.  Flash flooding is already occurring.

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 3834 12220 3827 12221 3827 12222 3826 12221
      3816 12222 3816 12233 3832 12238 3847 12247
      3860 12264 3868 12251

$$
rww
307 
WGUS76 KMTR 160229
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
629 PM PST THU DEC 15 2016

CAC055-160238-
/O.EXP.KMTR.FF.W.0017.000000T0000Z-161216T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Napa CA-
629 PM PST THU DEC 15 2016

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN NAPA COUNTY WILL EXPIRE
AT 630 PM PST...

Flooding is no longer expected to pose a threat. Please continue to
heed any remaining road closures.

LAT...LON 3834 12220 3827 12221 3827 12222 3826 12221
      3816 12222 3816 12233 3832 12238 3847 12247
      3860 12264 3868 12251

$$

WP

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 14, 6:07 PM PSTAreal Flood AdvisoryMTRMarin, Napa, Sonoma12 hr
Dec 15, 3:06 AM PSTSmall Craft AdvisoryMTR3 days
Dec 15, 3:40 AM PSTWind AdvisoryMTRAlameda, Contra Costa, Marin, Monterey, San Benito, San Mateo and 3 more21 hr
Dec 15, 10:24 AM PSTAreal Flood AdvisoryMTRMarin, Napa, Sonoma6 hr
Dec 15, 12:57 PM PSTFlash Flood WarningMTRMarin, Sonoma4 hr
Dec 15, 3:12 PM PSTAreal Flood AdvisoryMTRAlameda, Contra Costa4 hr
Dec 15, 3:16 PM PSTAreal Flood AdvisoryMTRCity and County of San Francisco, San Mateo4 hr

Nearby

Flash Flood Warnings in California, 2016Every flash flood warning in 2016

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.