Alert archive / Montana / Mesoscale Discussions in 2012
Mesoscale Discussion 1076
The Storm Prediction Center issued this mesoscale discussion at Jun 5, 2012, 4:21 PM MDT for 6 counties in Montana. It was in force for 84 min.
The area
The outline as issued.
The facts
- Issued
- Jun 5, 2012, 4:21 PM MDT (22:21 UTC)
- Expired
- Jun 5, 2012, 5:45 PM MDT
- In force
- 84 min
- Issued by
- the Storm Prediction Center
Counties Broadwater County, MT, Golden Valley County, MT, Meagher County, MT, Stillwater County, MT, Sweet Grass County, MT, Wheatland County, MT
The radar
The Billings radar (KBLX), 140 km from the middle of the area, began a volume at 22:24 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
Great_falls, MT (KTFX), launched 12:00Z, 10.4 hours before the alert went out and 146 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
- 111 J/kg
- Mixed-layer CIN
- -628 J/kg
- Mixed-layer LCL
- 1113 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 234 m²/s²
- 0-3 km storm-relative helicity
- 311 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
366
ACUS11 KWNS 052221
SWOMCD
SPC MCD 052221
MTZ000-052345-
MESOSCALE DISCUSSION 1076
NWS STORM PREDICTION CENTER NORMAN OK
0521 PM CDT TUE JUN 05 2012
AREAS AFFECTED...SWRN/S-CNTRL MT
CONCERNING...SEVERE THUNDERSTORM WATCH 359...
VALID 052221Z - 052345Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 359
CONTINUES.
SUMMARY...GREATEST NEAR-TERM SEVERE THREAT EXISTS WITH MEAGHER
COUNTY SUPERCELL...BUT ADDITIONAL SUPERCELLS SHOULD DEVELOP IN A
TRAINING PATTERN TO THE SE. PRIMARY RISK WILL REMAIN LARGE
HAIL...BUT A BRIEF TORNADO AND ISOLATED DAMAGING WINDS WILL BE
PROBABLE AS WELL.
DISCUSSION...MEAGHER COUNTY SUPERCELL HAS HAD A HISTORY OF REPORTED
HAIL TO 2 INCHES AND FUNNEL CLOUDS/POSSIBLE BRIEF TORNADO. THIS CELL
SHOULD EVENTUALLY PROPAGATE N OF THE LITTLE BELT MTNS...INTO A MORE
FAVORABLE TORNADIC ENVIRONMENT IN WW 360. ADDITIONAL SUPERCELL
DEVELOPMENT IS PROBABLE TO THE SE...IN AN ENVIRONMENT CHARACTERIZED
BY LOWER TO MIDDLE 50S SURFACE DEW POINTS. RAP-BASED RUC GUIDANCE
APPEARS TO BE GROSSLY MISREPRESENTING THE THERMODYNAMIC ENVIRONMENT
IN BOTH ANALYSIS AND 1-HR FORECASTS /SURFACE DEW POINTS AROUND 15 TO
30 DEG F LOWER COMPARED TO OBS AT LWT AND BIL/. WHICH IS RESULTING
IN SUBSTANTIALLY WEAKER MLCAPE IN MESOANALYSIS DATA COMPARED TO
OLDER GENERATION RUC GUIDANCE. THIS LATTER VERSION SUGGESTS MLCAPE
IS AS HIGH AS 1000-1500 J/KG WITHIN WW 359...WHICH APPEARS MORE
REASONABLE BASED ON MODIFIED 19Z TFX RAOB. GIVEN THE STRENGTH OF THE
FORCING AND DEEP-LAYER SHEAR ASSOCIATED WITH THE NEGATIVELY-TILTED
SHORT WAVE IMPULSE CENTERED ALONG THE ERN ID/SWRN MT BORDER...THREAT
FOR SUPERCELLS WILL REMAIN HIGH.
..GRAMS.. 06/05/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BYZ...TFX...
LAT...LON 46171188 46551205 46761149 46981100 46820917 46370885
45980884 45580900 45360947 45350982 45741095 46171188SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 4, 6:02 PM MDT | Tornado Watch | SPC | Blaine, Cascade, Chouteau, Fergus, Glacier, Hill and 6 more | 7 hr |
| Jun 4, 7:42 PM MDT | Mesoscale Discussion | SPC | Granite, Lake, Lincoln, Mineral, Missoula, Ravalli and 1 more | 93 min |
| Jun 4, 8:22 PM MDT | Mesoscale Discussion | SPC | Blaine, Chouteau, Fergus, Hill, Petroleum, Phillips and 1 more | 83 min |
| Jun 4, 10:08 PM MDT | Mesoscale Discussion | SPC | Lake, Lincoln, Mineral, Sanders | 67 min |
| Jun 4, 10:48 PM MDT | Mesoscale Discussion | SPC | Liberty, Pondera, Teton, Toole | 57 min |
| Jun 5, 12:54 PM MDT | Mesoscale Discussion | SPC | Broadwater, Carbon, Gallatin, Golden Valley, Madison, Meagher and 6 more | 2 hr |
| Jun 5, 1:37 PM MDT | Severe Thunderstorm Watch | SPC | Broadwater, Carbon, Gallatin, Golden Valley, Jefferson, Madison and 5 more | 7 hr |
| Jun 5, 1:56 PM MDT | Mesoscale Discussion | SPC | Blaine, Cascade, Chouteau, Fergus, Glacier, Hill and 8 more | 2 hr |
| Jun 5, 2:37 PM MDT | Tornado Watch | SPC | Blaine, Cascade, Chouteau, Fergus, Glacier, Hill and 6 more | 8 hr |
| Jun 5, 4:48 PM MDT | Mesoscale Discussion | SPC | Cascade, Chouteau, Fergus, Glacier, Golden Valley, Judith Basin and 6 more | 87 min |
Nearby
Mesoscale Discussions in Montana, 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.