Alert archive / Montana / Mesoscale Discussions in 2012
Mesoscale Discussion 1280
The Storm Prediction Center issued this mesoscale discussion at Jun 25, 2012, 7:12 PM MDT for 17 counties in Montana. It was in force for 93 min.
The area
The outline as issued.
The facts
- Issued
- Jun 25, 2012, 7:12 PM MDT (01:12 UTC)
- Expired
- Jun 25, 2012, 8:45 PM MDT
- In force
- 93 min
- Issued by
- the Storm Prediction Center
Counties Blaine County, MT, Chouteau County, MT, Dawson County, MT, Fergus County, MT, Garfield County, MT, Hill County, MT, Liberty County, MT, McCone County, MT, Petroleum County, MT, Phillips County, MT, Pondera County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Teton County, MT, Toole County, MT, Valley County, MT
The radar
The Great Falls radar (KTFX), 175 km from the middle of the area, began a volume at 01:15 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 00:00Z, 1.2 hours before the alert went out and 123 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
- 1195 J/kg
- Mixed-layer CIN
- -265 J/kg
- Mixed-layer LCL
- 1952 m above ground
- 0-6 km bulk shear
- 59 kt
- 0-1 km storm-relative helicity
- 34 m²/s²
- 0-3 km storm-relative helicity
- 154 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
The text
As transmitted, in the capitals the NWS used until 2016.
244
ACUS11 KWNS 260113
SWOMCD
SPC MCD 260112
MTZ000-260245-
MESOSCALE DISCUSSION 1280
NWS STORM PREDICTION CENTER NORMAN OK
0812 PM CDT MON JUN 25 2012
AREAS AFFECTED...NRN HALF OF MT
CONCERNING...SEVERE THUNDERSTORM WATCH 430...
VALID 260112Z - 260245Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 430
CONTINUES.
SUMMARY...THREAT FOR ISOLATED LARGE HAIL AND DAMAGING WIND IS
EXPECTED TO PERSIST NEXT FEW HOURS ACROSS A LARGE PART OF NRN MT.
DISCUSSION...STORMS CONTINUE DEVELOPING OVER MOUNTAINS OF SCNTRL
THROUGH WRN MT AND SUBSEQUENTLY MOVE NWD INTO AXIS OF RICHER LOW
LEVEL MOISTURE AND MODERATE INSTABILITY PRESENT OVER NRN MT. THE 00Z
RAOB DATA INDICATE VERY STEEP /9 C/KM/ 700-500 MB LAPSE RATES AND
1500-3000 J/KG MLCAPE...BUT A FAIRLY SUBSTANTIAL CAP WAS ALSO
PRESENT. CORRIDOR OF GREATEST SEVERE THREAT WILL EXIST IN A
RELATIVELY NARROW 50 MILE WIDE ZONE FROM NEAR CUT BANK TO JORDAN TO
GLENDIVE. IN THIS ZONE...STORMS THAT INITIATE OVER THE HIGHER
TERRAIN AND WITHIN THE MORE DEEPLY MIXED REGIME WILL INTENSIFY AS
THEY MOVE INTO INSTABILITY AXIS...BEFORE WEAKENING AS THEY ENCOUNTER
THE STRONGER CAP. SHEAR PROFILES WITH 40-50 KT EFFECTIVE SHEAR
SUPPORT SUPERCELLS...AND THIS MAY HELP STORMS TO SURVIVE A LITTLE
LONGER AS THEY LIFT NWD INTO THE MORE STRONGLY CAPPED BOUNDARY
LAYER.
AS THE BOUNDARY LAYER BEGINS TO COOL...SEVERE THREAT MAY BE MORE
PERSISTENT OVER NWRN MT THAN FARTHER EAST DUE TO LIKELY PRESENCE OF
DEEPER FORCING FOR ASCENT ASSOCIATED WITH NEWD EJECTING UPPER SPEED
MAX.
..DIAL.. 06/26/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...GGW...TFX...
LAT...LON 48821254 48920884 48710452 46880454 46890930 47571241
48821254SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 25, 10:27 PM MDT | Mesoscale Discussion | SPC | Blaine, Chouteau, Fergus, Garfield, Hill, Liberty and 3 more | 93 min |
| Jun 26, 12:23 AM MDT | Mesoscale Discussion | SPC | Blaine, Chouteau, Hill | 67 min |
| Jun 26, 6:16 AM MDT | Mesoscale Discussion | SPC | Glacier, Hill, Liberty, Pondera, Teton, Toole | 89 min |
| Jun 26, 11:08 AM MDT | Mesoscale Discussion | SPC | Blaine, Cascade, Chouteau, Glacier, Hill, Liberty and 3 more | 37 min |
| Jun 26, 11:20 AM MDT | Severe Thunderstorm Watch | SPC | Blaine, Cascade, Chouteau, Glacier, Hill, Lewis and Clark and 4 more | 6 hr |
| Jun 26, 2:06 PM MDT | Mesoscale Discussion | SPC | Daniels, Dawson, Fallon, McCone, Phillips, Prairie and 5 more | 54 min |
| Jun 26, 2:21 PM MDT | Mesoscale Discussion | SPC | Blaine, Cascade, Chouteau, Hill, Lewis and Clark, Liberty and 3 more | 54 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.