Alert archive / California / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 49, NWS Las Vegas, NV

September 7, 2017San Bernardino County, California

NWS Las Vegas, NV issued this severe thunderstorm warning at Sep 7, 2017, 3:38 PM PDT for San Bernardino County, California. It was in force for 37 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: Sep 7, 2017, 3:38 PM PDT (22:38 UTC)
Expired: Sep 7, 2017, 4:15 PM PDT
In force: 37 min
Issued by: NWS Las Vegas, NV
Area: Storm-based polygon
Hail: 1.75 in
Wind: 60.0 mph

County San Bernardino County, CA

The radar

The Las Vegas radar (KESX), 154 km from the middle of the area, began a volume at 22:38 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

Yuma Prvg Ground, AZ (K1Y7), launched 12:00Z, 10.6 hours before the alert went out and 220 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: 461 J/kg
Mixed-layer CIN: -388 J/kg
Mixed-layer LCL: 2327 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -4 m²/s²
0-3 km storm-relative helicity: 37 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

298 
WUUS55 KVEF 072238
SVRVEF
CAC071-072315-
/O.NEW.KVEF.SV.W.0049.170907T2238Z-170907T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Las Vegas NV
338 PM PDT THU SEP 7 2017

The National Weather Service in Las Vegas has issued a

* Severe Thunderstorm Warning for...
  South central San Bernardino County in southern California...

* Until 415 PM PDT

* At 337 PM PDT, a severe thunderstorm was located 28 miles south of
  Essex, or 36 miles west of Highway 95 At Mile Marker 29, moving
  north at 10 mph.

  HAZARD...Golf ball size hail and 60 mph wind gusts. 

  SOURCE...Radar indicated. 

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Expect 
           wind damage to roofs, siding, and trees. 

* This severe thunderstorm will remain over mainly rural areas of
  south central San Bernardino County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and deadly cloud to ground
lightning. Seek shelter inside a well-built structure. Stay away from
windows.

&&

LAT...LON 3425 11516 3424 11538 3449 11546 3451 11513
TIME...MOT...LOC 2237Z 175DEG 10KT 3432 11528 

HAIL...1.75IN
WIND...60MPH
 
$$

Morgan

2 follow-up statements

029 
WWUS55 KVEF 072253
SVSVEF

Severe Weather Statement
National Weather Service Las Vegas NV
353 PM PDT THU SEP 7 2017

CAC071-072315-
/O.CON.KVEF.SV.W.0049.000000T0000Z-170907T2315Z/
San Bernardino CA-
353 PM PDT THU SEP 7 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM PDT
FOR SOUTH CENTRAL SAN BERNARDINO COUNTY...

At 353 PM PDT, a severe thunderstorm was located 27 miles south of
Essex, or 35 miles west of Highway 95 At Mile Marker 29, moving 
north at 10 mph. This storm had begun to weaken, but was still 
capable of producing large hail and damaging winds.

HAZARD...60 mph wind gusts and quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees. 

This severe thunderstorm will remain over mainly rural areas of south
central San Bernardino County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3429 11516 3429 11538 3449 11541 3451 11513
TIME...MOT...LOC 2253Z 194DEG 7KT 3434 11526 

HAIL...1.00IN
WIND...60MPH
 
$$

Morgan

527 
WWUS55 KVEF 072309
SVSVEF

Severe Weather Statement
National Weather Service Las Vegas NV
409 PM PDT THU SEP 7 2017

CAC071-072318-
/O.EXP.KVEF.SV.W.0049.000000T0000Z-170907T2315Z/
San Bernardino CA-
409 PM PDT THU SEP 7 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL SAN BERNARDINO
COUNTY WILL EXPIRE AT 415 PM PDT...
                
The storm over rural south central San Bernardino County had 
weakened, and no longer poses an immediate threat to life or 
property. Therefore the warning will be allowed to expire.

LAT...LON 3429 11516 3429 11538 3449 11541 3451 11513
TIME...MOT...LOC 2308Z 175DEG 10KT 3438 11526 

$$

Morgan

The office that day

Everything else NWS Las Vegas, NV issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 7, 2:10 PM PDT	Flash Flood Watch	VEF	San Bernardino	55 hr
Sep 7, 2:14 PM PDT	Flash Flood Warning	VEF	San Bernardino	3 hr

Nearby

Severe Thunderstorm Warnings in California, 2017 Every severe thunderstorm 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.