Alert archive / California / Tornado Warnings in 2017

Tornado Warning 3, NWS Sacramento, CA

April 13, 2017Nevada County, Yuba County, California

NWS Sacramento, CA issued this tornado warning at Apr 13, 2017, 3:11 PM PDT for Nevada County, Yuba County, California. It was in force for 49 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Apr 13, 2017, 3:11 PM PDT (22:11 UTC)
Expired: Apr 13, 2017, 4:00 PM PDT
In force: 49 min
Issued by: NWS Sacramento, CA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties Nevada County, CA, Yuba County, CA

The radar

The Beale AFB radar (KBBX), 50 km from the middle of the area, began a volume at 22:13 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, 10.2 hours before the alert went out and 181 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 5 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 696 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: 107 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

227 
WFUS56 KSTO 132211
TORSTO
CAC057-115-132300-
/O.NEW.KSTO.TO.W.0003.170413T2211Z-170413T2300Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sacramento CA
311 PM PDT THU APR 13 2017

The National Weather Service in Sacramento has issued a

* Tornado Warning for...
  South central Yuba County in central California...
  West central Nevada County in northern California...

* Until 400 PM PDT
    
* At 311 PM PDT, a severe thunderstorm capable of producing a tornado
  was located over Smartville, or 12 miles west of Grass Valley,
  moving northeast at 25 mph.

  HAZARD...Tornado. 

  SOURCE...Radar indicated rotation. 

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Damage to roofs, windows, and vehicles will 
           occur.  Tree damage is likely. 

* This dangerous storm will be near...
  Lake Wildwood and Rough And Ready around 320 PM PDT. 
  Grass Valley and Cedar Ridge around 325 PM PDT. 

Other locations impacted by this tornadic thunderstorm include Penn
Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This Tornado Warning replaces the Severe Thunderstorm Warning issued
for the same area.

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3906 12132 3920 12142 3934 12113 3919 12100
TIME...MOT...LOC 2211Z 240DEG 49KT 3917 12127 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

cs

2 follow-up statements

841 
WWUS56 KSTO 132235
SVSSTO

Severe Weather Statement
National Weather Service Sacramento CA
335 PM PDT THU APR 13 2017

CAC115-132245-
/O.CAN.KSTO.TO.W.0003.000000T0000Z-170413T2300Z/
Yuba CA-
335 PM PDT THU APR 13 2017

...THE TORNADO WARNING FOR SOUTH CENTRAL YUBA COUNTY IS CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

LAT...LON 3915 12124 3922 12127 3934 12113 3919 12100
TIME...MOT...LOC 2235Z 216DEG 9KT 3923 12120 

$$

CAC057-132300-
/O.CON.KSTO.TO.W.0003.000000T0000Z-170413T2300Z/
Nevada CA-
335 PM PDT THU APR 13 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 400 PM PDT FOR WEST
CENTRAL NEVADA COUNTY...
    
At 335 PM PDT, a severe thunderstorm capable of producing a tornado
was located over Lake Wildwood, or 7 miles west of Grass Valley,
moving northeast at 10 mph.

HAZARD...Tornado. 

SOURCE...Radar indicated rotation. 

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely. 

This dangerous storm will be near...
  Rough And Ready around 350 PM PDT. 
  Grass Valley around 400 PM PDT. 

Other locations impacted by this tornadic thunderstorm include Penn
Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to an interior room on the lowest floor of a
sturdy building. Avoid windows. If you are outdoors, in a mobile
home, or in a vehicle, move to the closest substantial shelter and
protect yourself from flying debris.

&&

LAT...LON 3915 12124 3922 12127 3934 12113 3919 12100
TIME...MOT...LOC 2235Z 216DEG 9KT 3923 12120 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

cs

746 
WWUS56 KSTO 132255
SVSSTO

Severe Weather Statement
National Weather Service Sacramento CA
355 PM PDT THU APR 13 2017

CAC057-132305-
/O.EXP.KSTO.TO.W.0003.000000T0000Z-170413T2300Z/
Nevada CA-
355 PM PDT THU APR 13 2017

...THE TORNADO WARNING FOR WEST CENTRAL NEVADA COUNTY WILL EXPIRE AT
400 PM PDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore the warning will be allowed to expire.

LAT...LON 3915 12124 3922 12127 3934 12113 3919 12100
TIME...MOT...LOC 2255Z 240DEG 49KT 3935 12093 

$$

cs

The office that day

Everything else NWS Sacramento, CA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 13, 10:43 AM PDT	Special Weather Statement	STO	Sacramento	62 min
Apr 13, 11:14 AM PDT	Special Weather Statement	STO	Yuba	46 min
Apr 13, 12:08 PM PDT	Special Weather Statement	STO	El Dorado	52 min
Apr 13, 12:19 PM PDT	Special Weather Statement	STO	Calaveras	41 min
Apr 13, 12:53 PM PDT	Special Weather Statement	STO	Sacramento	52 min
Apr 13, 1:31 PM PDT	Special Weather Statement	STO	Sutter	44 min
Apr 13, 1:47 PM PDT	Special Weather Statement	STO	Glenn	43 min
Apr 13, 2:02 PM PDT	Special Weather Statement	STO	Calaveras	43 min
Apr 13, 2:19 PM PDT	Special Weather Statement	STO	Shasta	41 min
Apr 13, 2:45 PM PDT	Special Weather Statement	STO	Yuba	30 min
Apr 13, 2:48 PM PDT	Special Weather Statement	STO	Butte	42 min
Apr 13, 2:51 PM PDT	Severe Thunderstorm Warning	STO	Nevada, Yuba	24 min
Apr 13, 3:33 PM PDT	Special Weather Statement	STO	Placer	42 min
Apr 13, 3:40 PM PDT	Special Weather Statement	STO	Butte	35 min
Apr 13, 4:53 PM PDT	Special Weather Statement	STO	Butte	37 min

Nearby

Tornado Warnings in California, 2017 Every tornado warning in 2017 Tornadoes 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.