Alert archive / Montana / Mesoscale Discussions in 2012
Mesoscale Discussion 1256
The Storm Prediction Center issued this mesoscale discussion at Jun 24, 2012, 3:47 AM MDT for 4 counties in Montana. It was in force for 88 min.
The area
The outline as issued.
The facts
- Issued
- Jun 24, 2012, 3:47 AM MDT (09:47 UTC)
- Expired
- Jun 24, 2012, 5:15 AM MDT
- In force
- 88 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 5%
Counties Daniels County, MT, Roosevelt County, MT, Sheridan County, MT, Valley County, MT
The radar
The Glasgow radar (KGGW), 66 km from the middle of the area, began a volume at 09:50 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
Glasgow Intl Airport, MT (KGGW), launched 00:00Z, 9.8 hours before the alert went out and 64 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2402 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 29 m²/s²
- 0-3 km storm-relative helicity
- 123 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
102
ACUS11 KWNS 240948
SWOMCD
SPC MCD 240947
NDZ000-MTZ000-241115-
MESOSCALE DISCUSSION 1256
NWS STORM PREDICTION CENTER NORMAN OK
0447 AM CDT SUN JUN 24 2012
AREAS AFFECTED...NERN MT...NWRN ND
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 240947Z - 241115Z
PROBABILITY OF WATCH ISSUANCE...5 PERCENT
SUMMARY...LOW PROBABILITIES FOR SEVERE HAIL/WIND MAY ACCOMPANY
CONVECTION SPREADING ACROSS NORTHEASTERN MONTANA DURING THE NEXT
COUPLE OF HOURS. HOWEVER...THREAT APPEARS TOO MARGINAL/SHORT-LIVED
TO REQUIRE A WW.
DISCUSSION...FORCING ASSOCIATED WITH A WEAK IMPULSE ROUNDING THE
CREST OF THE BUILDING LARGER SCALE RIDGE ACROSS THE REGION APPEARS
TO HAVE PROVIDED SUPPORT FOR SCATTERED FAIRLY VIGOROUS ONGOING STORM
DEVELOPMENT NORTHWEST THROUGH NORTH OF GLASGOW. ACTIVITY IS LIKELY
BASED WITHIN A ZONE OF ENHANCED LOWER/MID TROPOSPHERIC WARM
ADVECTION...ON THE NORTHERN PERIPHERY OF MORE STRONGLY CAPPING
ELEVATED MIXED LAYER AIR. THE DEGREE OF CAPE PRESENT REMAINS A BIT
UNCLEAR...BUT VERTICAL SHEAR WITHIN THE CONVECTIVE LAYER IS
STRONG...AND LATEST WDSS-II MESH SUGGESTS THAT ACTIVITY COULD BE
PRODUCING OCCASIONAL SEVERE HAIL. IT DOES NOT APPEAR OUT OF THE
QUESTION THAT A FEW STRONG WIND GUSTS COULD ACCOMPANY CONVECTION AS
IT DEVELOPS EASTWARD NEAR/SOUTH OF THE SASKATCHEWAN BORDER DURING
THE NEXT COUPLE OF HOURS. HOWEVER...IT DOES APPEAR THAT ACTIVITY
MAY BEGIN TO WEAKEN/DIMINISH BY THE 11-13Z TIME FRAME...WHEN LATEST
RAPID REFRESH SUGGESTS THAT SUPPORTING FORCING WILL BEGIN TO
WEAKEN/SHIFT NORTH OF THE INTERNATIONAL BORDER.
..KERR/CARBIN.. 06/24/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BIS...GGW...
LAT...LON 48980789 49320685 49350512 49160380 48550384 48120518
48150622 48230751 48520786 48980789SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 23, 7:36 PM MDT | Mesoscale Discussion | SPC | Flathead, Lake, Pondera, Teton | 84 min |
| Jun 24, 8:16 AM MDT | Mesoscale Discussion | SPC | Richland, Roosevelt, Sheridan | 89 min |
| Jun 24, 8:31 AM MDT | Severe Thunderstorm Watch | SPC | Daniels, Richland, Roosevelt, Sheridan | 5 hr |
| Jun 24, 11:24 AM MDT | Mesoscale Discussion | SPC | Daniels, Richland, Roosevelt, Sheridan | 2 hr |
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.