Alert archive / Colorado / Special Weather Statements in 2018

Special Weather Statement, NWS Grand Junction, CO

August 21, 2018Mesa County, Colorado

NWS Grand Junction, CO issued this special weather statement at Aug 21, 2018, 11:08 AM MDT for Mesa County, Colorado. It was in force for 52 min. 1 report 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: Aug 21, 2018, 11:08 AM MDT (17:08 UTC)
Expired: Aug 21, 2018, 12:00 PM MDT
In force: 52 min
Issued by: NWS Grand Junction, CO

County Mesa County, CO

The radar

The Grand Junction radar (KGJX), 28 km from the middle of the area, began a volume at 17:10 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

Time	Report	Where	Remark
Aug 21, 11:08 AM MDT	HAIL 0.25	Grand Jct. 3nw, CO	0.40 INCH DIAMETER HAIL FOR 5 MINUTES.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Grand Junction, CO (KGJT), launched 12:00Z, 5.1 hours before the alert went out and 11 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: 11 J/kg
Mixed-layer CIN: -403 J/kg
Mixed-layer LCL: 2499 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 11 m²/s²
0-3 km storm-relative helicity: 121 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

855 
WWUS85 KGJT 211708
SPSGJT

Special Weather Statement
National Weather Service Grand Junction CO
1108 AM MDT TUE AUG 21 2018
 
COZ003-006-007-211800-
Roan and Tavaputs Plateaus CO-Debeque to Silt Corridor CO-
Grand Valley CO-
1108 AM MDT TUE AUG 21 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL MESA COUNTY UNTIL
NOON MDT...

At 1108 AM MDT, Doppler radar was tracking a strong thunderstorm 
near and just north of Grand Junction, moving northeast at 30 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Grand Junction.

LAT...LON 3912 10859 3915 10862 3937 10840 3933 10831
      3925 10827
TIME...MOT...LOC 1708Z 229DEG 28KT 3915 10858 

$$

Charnick

The office that day

Everything else NWS Grand Junction, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 20, 8:35 PM MDT	Special Weather Statement	GJT		40 min
Aug 21, 4:02 AM MDT	Flash Flood Watch	GJT	Archuleta, Delta, Dolores, Eagle, Garfield, Hinsdale and 11 more	44 hr
Aug 21, 10:50 AM MDT	Special Weather Statement	GJT	Mesa	25 min
Aug 21, 11:19 AM MDT	Special Weather Statement	GJT	Mesa	26 min
Aug 21, 11:36 AM MDT	Severe Thunderstorm Warning	GJT	Mesa	24 min
Aug 21, 11:53 AM MDT	Severe Thunderstorm Warning	GJT	Garfield, Mesa	37 min
Aug 21, 12:00 PM MDT	Severe Thunderstorm Warning	GJT	Mesa	16 min
Aug 21, 12:29 PM MDT	Severe Thunderstorm Warning	GJT	Garfield, Mesa	46 min
Aug 21, 12:57 PM MDT	Special Weather Statement	GJT	Mesa	33 min
Aug 21, 1:09 PM MDT	Severe Thunderstorm Warning	GJT	Garfield, Mesa	36 min
Aug 21, 1:26 PM MDT	Special Weather Statement	GJT	Pitkin	34 min
Aug 21, 1:48 PM MDT	Special Weather Statement	GJT	Garfield	42 min
Aug 21, 2:18 PM MDT	Special Weather Statement	GJT	Dolores	42 min
Aug 21, 2:33 PM MDT	Special Weather Statement	GJT		27 min
Aug 21, 3:25 PM MDT	Special Weather Statement	GJT	Montrose	50 min
Aug 21, 3:26 PM MDT	Special Weather Statement	GJT		34 min
Aug 21, 3:41 PM MDT	Flash Flood Warning	GJT	Mesa, Montrose	3 hr
Aug 21, 5:19 PM MDT	Areal Flood Advisory	GJT	Mesa	3 hr
Aug 21, 10:59 AM MDT	Special Weather Statement	GJT	Grand	46 min
Aug 21, 11:14 AM MDT	Severe Thunderstorm Warning	GJT	Grand, Uintah	46 min
Aug 21, 1:27 PM MDT	Special Weather Statement	GJT	Grand	48 min
Aug 21, 2:14 PM MDT	Special Weather Statement	GJT	San Juan	46 min
Aug 21, 2:38 PM MDT	Special Weather Statement	GJT	Grand	52 min
Aug 21, 2:47 PM MDT	Special Weather Statement	GJT	Grand	28 min
Aug 21, 3:14 PM MDT	Special Weather Statement	GJT	Grand	46 min

Nearby

Special Weather Statements in Colorado, 2018 Every special weather statement in 2018

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.