Alert archive / Nevada / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 21, NWS Las Vegas, NV

July 20, 2009Clark County, Nevada

NWS Las Vegas, NV issued this severe thunderstorm warning at Jul 20, 2009, 11:49 AM PDT for Clark County, Nevada. It was in force for 41 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: Jul 20, 2009, 11:49 AM PDT (18:49 UTC)
Expired: Jul 20, 2009, 12:30 PM PDT
In force: 41 min
Issued by: NWS Las Vegas, NV
Area: Storm-based polygon

County Clark County, NV

The radar

The Las Vegas radar (KESX), 9 km from the middle of the area, began a volume at 18:51 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

Mercury/Desert R, NV (KDRA), launched 12:00Z, 6.8 hours before the alert went out and 135 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: 70 J/kg
Mixed-layer CIN: -356 J/kg
Mixed-layer LCL: 3034 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 19 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS55 KVEF 201849
SVRVEF
NVC003-201930-
/O.NEW.KVEF.SV.W.0021.090720T1849Z-090720T1930Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
1149 AM PDT MON JUL 20 2009

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTH CENTRAL CLARK COUNTY IN SOUTHERN NEVADA...

* UNTIL 1230 PM PDT.

* AT 1144 AM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL.  THIS
  STORM WAS LOCATED OVER SOUTH CENTRAL CLARK COUNTY...OR 15 MILES
  NORTHWEST OF SEARCHLIGHT...AND MOVING EAST AT 5 MPH.

* THE SEVERE THUNDERSTORM WILL REMAIN OVER MAINLY RURAL AREAS OF THE
  INDICATED COUNTY. 

  HOWEVER HIGHWAY 95 IS UNDER THIS WARNING FROM MAINLY MILE MARKER
  25 TO MILE MARKER 52. STRONG AND GUSTY WINDS MAY BE SEEN FROM THIS
  STORM WHICH COULD CREATE LOCALE AREAS OF BLOWING DUST AND SAND AND 
  RAPIDLY LOWER VISIBILITIES.

LAT...LON 3590 11487 3550 11488 3549 11515 3587 11514
TIME...MOT...LOC 1846Z 274DEG 5KT 3567 11502

$$

JENSEN

2 follow-up statements

000 
WWUS55 KVEF 201915
SVSVEF

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1215 PM PDT MON JUL 20 2009

NVC003-201930-
/O.CON.KVEF.SV.W.0021.000000T0000Z-090720T1930Z/
CLARK NV-
1215 PM PDT MON JUL 20 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 PM PDT
FOR SOUTH CENTRAL CLARK COUNTY...

AT 1214 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL.  THIS STORM WAS LOCATED OVER SOUTH CENTRAL CLARK COUNTY...OR 14
MILES NORTH OF SEARCHLIGHT...MOVING EAST AT 5 MPH.

THE SEVERE THUNDERSTORM WILL OTHERWISE REMAIN OVER MAINLY RURAL AREAS
OF THE INDICATED COUNTY.

HOWEVER HIGHWAY 95 IS UNDER THIS WARNING FROM MAINLY MILE MARKER   
25 TO MILE MARKER 52. STRONG AND GUSTY WINDS MAY BE SEEN FROM THIS   
STORM WHICH COULD CREATE LOCALE AREAS OF BLOWING DUST AND SAND AND   
RAPIDLY LOWER VISIBILITIES.


LAT...LON 3590 11487 3550 11488 3549 11515 3587 11514
TIME...MOT...LOC 1915Z 274DEG 5KT 3567 11497

$$

JENSEN

000 
WWUS55 KVEF 201930
SVSVEF

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1230 PM PDT MON JUL 20 2009

NVC003-201939-
/O.EXP.KVEF.SV.W.0021.000000T0000Z-090720T1930Z/
CLARK NV-
1230 PM PDT MON JUL 20 2009

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL CLARK COUNTY
WILL EXPIRE AT 1230 PM PDT...

THUNDERSTORMS REMAIN OVER THE SOUTHERN PORTION OF CLARK COUNTY BUT 
RADAR INDICATES THAT THE POTENTIAL FOR LARGE HAIL HAS DIMINISHED. 
THUS WILL ALLOW THE SEVERE THUNDERSTORM WARNING TO EXPIRE AS OF 1230 
PM PDT.

LAT...LON 3590 11487 3550 11488 3549 11515 3587 11514
TIME...MOT...LOC 1929Z 274DEG 5KT 3567 11495

$$

JENSEN

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 19, 6:14 PM PDT	Severe Thunderstorm Warning	VEF	Clark	31 min
Jul 20, 10:43 AM PDT	Flash Flood Warning	VEF	Clark	2 hr
Jul 20, 10:47 AM PDT	Severe Thunderstorm Warning	VEF	Clark	43 min
Jul 20, 11:50 AM PDT	Flash Flood Warning	VEF	Clark	115 min
Jul 20, 1:05 PM PDT	Flash Flood Warning	VEF	Clark	115 min
Jul 20, 1:21 PM PDT	Severe Thunderstorm Warning	VEF	Clark	39 min

Nearby

Severe Thunderstorm Warnings in Nevada, 2009 Every severe thunderstorm warning in 2009

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.