Alert archive / Utah / Mesoscale Discussions in 2012
Mesoscale Discussion 1855
The Storm Prediction Center issued this mesoscale discussion at Sep 1, 2012, 5:49 PM MDT for 20 counties in Utah; Uinta County, Wyoming. It was in force for 86 min.
The area
The outline as issued.
The facts
- Issued
- Sep 1, 2012, 5:49 PM MDT (23:49 UTC)
- Expired
- Sep 1, 2012, 7:15 PM MDT
- In force
- 86 min
- Issued by
- the Storm Prediction Center
All 21 counties
Beaver County, UT, Box Elder County, UT, Cache County, UT, Carbon County, UT, Davis County, UT, Duchesne County, UT, Emery County, UT, Juab County, UT, Millard County, UT, Morgan County, UT, Piute County, UT, Rich County, UT, Salt Lake County, UT, Sanpete County, UT, Sevier County, UT, Summit County, UT, Tooele County, UT, Utah County, UT, Wasatch County, UT, Weber County, UT, Uinta County, WY
The radar
The Salt Lake City radar (KMTX), 210 km from the middle of the area, began a volume at 23:50 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
Salt Lake City I, UT (KSLC), launched 12:00Z, 11.8 hours before the alert went out and 141 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.
- Mixed-layer CAPE
- 158 J/kg
- Mixed-layer CIN
- -127 J/kg
- Mixed-layer LCL
- 978 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 98 m²/s²
- 0-3 km storm-relative helicity
- 111 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted, in the capitals the NWS used until 2016.
144
ACUS11 KWNS 012349
SWOMCD
SPC MCD 012349
WYZ000-UTZ000-IDZ000-NVZ000-020115-
MESOSCALE DISCUSSION 1855
NWS STORM PREDICTION CENTER NORMAN OK
0649 PM CDT SAT SEP 01 2012
AREAS AFFECTED...MUCH OF UTAH...SRN ID...FAR SWRN WY...NWRN CO
CONCERNING...SEVERE THUNDERSTORM WATCH 604...
VALID 012349Z - 020115Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 604
CONTINUES.
SUMMARY...THE SEVERE THREAT IS EXPECTED TO CONTINUE IN AND AROUND WW
604 FOR THE NEXT FEW HOURS BUT OVERALL COVERAGE OF SEVERE STORMS
SHOULD GRADUALLY DECREASE.
DISCUSSION...RECENT RADAR TRENDS DEPICT A DIMINISHING NUMBER OF
TSTMS ACROSS MUCH OF THE WATCH AREA. THIS IS LIKELY A RESULT OF
REDUCED LARGE-SCALE FORCING AS THE LATEST WV SATELLITE IMAGERY SHOWS
A SHORTWAVE TROUGH IS NOW OVERHEAD OR JUST E OF N-CNTRL UT. DESPITE
THE REDUCED COVERAGE...THE ENVIRONMENT REMAINS FAVORABLE FOR
ORGANIZED CONVECTION CAPABLE OF PRODUCING SEVERE WIND/HAIL. RECENT
DEVELOPMENT ACROSS TOOELE CO APPEARS TO HAVE ORGANIZED INTO A
RIGHT-MOVING SUPERCELL. GREATEST POTENTIAL FOR ADDITIONAL SEVERE
TSTMS IS EXPECTED TO BE ACROSS W-CNTRL EWD INTO CNTRL UT.
N OF THE WATCH AREA /SRN ID/...SHEAR PROFILES ARE NOT QUITE AS
STRONG BUT GIVEN THE DEWPOINTS IN THE MID 50S AND MODEST INSTABILITY
/MLCAPE AOA 500 J/KG/ A FEW STRONG TO BRIEFLY SEVERE WIND GUSTS ARE
POSSIBLE...ESPECIALLY AS THE ACTIVITY PROGRESSES EWD INTO A DRY
LOW-LEVEL ENVIRONMENT.
E OF THE WATCH AREA /NWRN CO/...SHEAR PROFILE AND INSTABILITY ARE
WEAKER BUT THE ONGOING ACTIVITY HAS SHOWN THE POTENTIAL FOR A FEW
STRONG WIND GUSTS. TSTM ACTIVITY ACROSS THIS AREA MAY INTENSIFY AS
THE SHEAR PROFILE GRADUALLY INCREASES /DEPICTED WELL ON THE GJX VAD
PROFILE/. HOWEVER...WEAK INSTABILITY AND FORCING WILL LIKELY LIMIT
TSTM COVERAGE AND THE OVERALL SEVERE THREAT.
..MOSIER.. 09/01/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...RIW...GJT...SLC...PIH...VEF...LKN...
LAT...LON 38141406 42001404 42001106 41591104 41571006 41001004
41000998 39820996 39441001 39101015 38941018 38861017
38641008 38491003 38521179 38411183 38161183 38141406SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 1, 12:31 PM MDT | Mesoscale Discussion | SPC | Beaver, Box Elder, Cache, Carbon, Davis, Duchesne and 16 more | 119 min |
| Sep 1, 12:59 PM MDT | Severe Thunderstorm Watch | SPC | Beaver, Box Elder, Cache, Carbon, Davis, Duchesne and 14 more | 8 hr |
| Sep 1, 2:31 PM MDT | Mesoscale Discussion | SPC | Kane, San Juan | 89 min |
| Sep 1, 3:02 PM MDT | Mesoscale Discussion | SPC | Beaver, Box Elder, Cache, Carbon, Davis, Duchesne and 15 more | 88 min |
Nearby
Mesoscale Discussions in Utah, 2012Mesoscale Discussions in Wyoming, 2012Every 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.