Alert archive / Utah / Mesoscale Discussions in 2012

Mesoscale Discussion 830

May 18, 2012Moffat County, Colorado; Daggett County, Duchesne County, Uintah County, Utah; Sweetwater County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at May 18, 2012, 11:05 AM MDT for Moffat County, Colorado; Daggett County, Duchesne County, Uintah County, Utah; Sweetwater County, Wyoming. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: May 18, 2012, 11:05 AM MDT (17:05 UTC)
Expired: May 18, 2012, 1:00 PM MDT
In force: 115 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Moffat County, CO, Daggett County, UT, Duchesne County, UT, Uintah County, UT, Sweetwater County, WY

The radar

The Riverton/Lander radar (KRIW), 213 km from the middle of the area, began a volume at 17:06 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

Riverton, WY (KRIW), launched 12:00Z, 5.1 hours before the alert went out and 214 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1683 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 149 m²/s²
0-3 km storm-relative helicity: 229 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.

855 
ACUS11 KWNS 181705
SWOMCD
SPC MCD 181705 
WYZ000-COZ000-UTZ000-181900-

MESOSCALE DISCUSSION 0830
NWS STORM PREDICTION CENTER NORMAN OK
1205 PM CDT FRI MAY 18 2012

AREAS AFFECTED...NERN UT...NWRN CO AND SWRN WY

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 181705Z - 181900Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...STORMS DEVELOPING FROM NERN UT...NWRN CO INTO SWRN WY WILL
POST A THREAT FOR ISOLATED DAMAGING WIND AND MARGINALLY SEVERE HAIL
INTO THE AFTERNOON. AREA WILL CONTINUE TO BE MONITORED FOR A
POSSIBLE SEVERE THUNDERSTORM WATCH.

DISCUSSION...LATE THIS MORNING A COLD FRONT EXTENDS FROM SERN WY
SWWD THROUGH CNTRL AND SWRN UT. THUNDERSTORMS WILL LIKELY CONTINUE
DEVELOPING ALONG THIS BOUNDARY AND OVER THE HIGHER TERRAIN WITHIN
ZONE OF DEEPER ASCENT ACCOMPANYING A PROGRESSIVE SHORTWAVE TROUGH.
WITH NEAR SFC DEWPOINTS IN THE 30S...INSTABILITY WILL REMAIN LIMITED
TO AOB 500 J/KG PROVIDING A POTENTIAL LIMITING FACTOR FOR A MORE
ROBUST SEVERE STORM THREAT. HOWEVER...STEEP LAPSE RATES AND
INVERTED-V THERMODYNAMIC PROFILES WITH INCREASINGLY LARGE BOUNDARY
LAYER TEMPERATURE DEWPOINT SPREADS WILL PROMOTE A THREAT OF ISOLATED
DAMAGING WIND GUSTS AS STORMS DEVELOP THIS AFTERNOON.

..DIAL/WEISS.. 05/18/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...CYS...RIW...GJT...SLC...

LAT...LON   41980726 40510787 39490957 40041098 41660987 42440804
            41980726

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 18, 2:54 PM MDT	Mesoscale Discussion	SPC	Goshen, Niobrara, Platte	96 min
May 18, 4:19 PM MDT	Mesoscale Discussion	SPC	Hot Springs, Johnson, Natrona, Washakie	56 min

Nearby

Mesoscale Discussions in Utah, 2012 Mesoscale Discussions in Colorado, 2012 Mesoscale Discussions in Wyoming, 2012 Every mesoscale discussion in 2012

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.