Alert archive / Montana / Mesoscale Discussions in 2012
Mesoscale Discussion 1573
The Storm Prediction Center issued this mesoscale discussion at Jul 24, 2012, 2:04 PM MDT for 7 counties in Montana; 7 counties in North Dakota. It was in force for 86 min.
The area
The outline as issued.
The facts
- Issued
- Jul 24, 2012, 2:04 PM MDT (20:04 UTC)
- Expired
- Jul 24, 2012, 3:30 PM MDT
- In force
- 86 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
Counties Custer County, MT, Dawson County, MT, Fallon County, MT, Prairie County, MT, Richland County, MT, Sheridan County, MT, Wibaux County, MT, Burke County, ND, Divide County, ND, Golden Valley County, ND, McKenzie County, ND, Mountrail County, ND, Renville County, ND, Williams County, ND
The radar
The Glasgow radar (KGGW), 207 km from the middle of the area, began a volume at 20:05 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
Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 8.1 hours before the alert went out and 206 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
- 832 J/kg
- Mixed-layer CIN
- -181 J/kg
- Mixed-layer LCL
- 887 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 146 m²/s²
- 0-3 km storm-relative helicity
- 145 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.6
The text
As transmitted, in the capitals the NWS used until 2016.
434
ACUS11 KWNS 242005
SWOMCD
SPC MCD 242004
NDZ000-MTZ000-242130-
MESOSCALE DISCUSSION 1573
NWS STORM PREDICTION CENTER NORMAN OK
0304 PM CDT TUE JUL 24 2012
AREAS AFFECTED...ERN MT...WRN ND
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 242004Z - 242130Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...A THREAT FOR ISOLATED SVR THUNDERSTORMS WILL EXIST THROUGH
THE AFTERNOON HOURS...AND THE ISSUANCE OF A WW IS POSSIBLE.
DISCUSSION...INSOLATION AND RELATIVELY STEEPER LOW-LEVEL LAPSE RATES
WITHIN A NARROW CORRIDOR ALONG AND EAST OF A SFC TROUGH AXIS --
ORIENTED NNE/SSW ACROSS ERN MT -- IS CONTRIBUTING TO MLCAPE VALUES
OF 500-1000 J/KG. AND...WITH ENHANCED MID-LEVEL FLOW IN ASSOCIATION
WITH THE GLANCING INFLUENCE OF A CLOSED LOW CROSSING ALBERTA AND
SASKATCHEWAN...AROUND 35 KT OF DEEP SHEAR ARE INDICATED BY GLASGOW
AND BISMARCK VWP DATA. THIS WILL SUPPORT A FEW VIGOROUS
UPDRAFTS/ORGANIZED CONVECTIVE ELEMENTS WITH CONVECTION EVOLVING
NEAR/EAST OF THE TROUGH AXIS. HOWEVER...THE CORRIDOR OF OVERLAP OF
MARGINAL INSTABILITY AND MODERATE SHEAR IS BEING CONSTRICTED IN
SPATIAL EXTENT BY ONGOING CLOUDINESS/SHOWERS/ELEVATED THUNDERSTORMS
FROM SWRN INTO CNTRL/N-CNTRL ND. HOWEVER...PRIOR TO CONVECTION
REACHING THE REGION OF DECREASED BUOYANCY OWING TO CLOUD/RAIN-COOLED
AIR...AN ISOLATED SVR THREAT MAY EVOLVE DURING THE NEXT FEW
HOURS...WITH SVR WIND GUSTS AND SVR HAIL THE PRIMARY CONCERNS.
..COHEN/HART.. 07/24/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BIS...BYZ...GGW...
LAT...LON 48900159 47910169 47220326 46570389 45990432 45620512
45550629 45680690 46120654 47370539 48680475 48990423
49030311 48900159SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 24, 4:42 PM MDT | Mesoscale Discussion | SPC | Adams, Billings, Bowman, Dunn, Emmons, Golden Valley and 6 more | 93 min |
Nearby
Mesoscale Discussions in Montana, 2012Mesoscale Discussions in North Dakota, 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.