Alert archive / Montana / Mesoscale Discussions in 2015
Mesoscale Discussion 856
The Storm Prediction Center issued this mesoscale discussion at Jun 1, 2015, 1:46 PM MDT for 19 counties in Montana. It was in force for 89 min.
The area
The outline as issued.
The facts
- Issued
- Jun 1, 2015, 1:46 PM MDT (19:46 UTC)
- Expired
- Jun 1, 2015, 3:15 PM MDT
- In force
- 89 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 80%
Counties Broadwater County, MT, Carbon County, MT, Cascade County, MT, Fergus County, MT, Gallatin County, MT, Golden Valley County, MT, Jefferson County, MT, Judith Basin County, MT, Lewis and Clark County, MT, Madison County, MT, Meagher County, MT, Musselshell County, MT, Park County, MT, Petroleum County, MT, Stillwater County, MT, Sweet Grass County, MT, Treasure County, MT, Wheatland County, MT, Yellowstone County, MT
The radar
The Billings radar (KBLX), 142 km from the middle of the area, began a volume at 19:48 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Great_falls, MT (KTFX), launched 12:00Z, 7.8 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
- 43 J/kg
- Mixed-layer CIN
- -204 J/kg
- Mixed-layer LCL
- 1644 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 102 m²/s²
- 0-3 km storm-relative helicity
- 67 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
311
ACUS11 KWNS 011946
SWOMCD
SPC MCD 011946
MTZ000-012115-
MESOSCALE DISCUSSION 0856
NWS STORM PREDICTION CENTER NORMAN OK
0246 PM CDT MON JUN 01 2015
AREAS AFFECTED...SWRN THROUGH CNTRL MT
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 011946Z - 012115Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...STORMS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY FROM
PARTS OF SWRN THROUGH CNTRL MT THIS AFTERNOON. DAMAGING WIND AND
LARGE HAIL WILL BE THE MAIN THREATS. A SEVERE THUNDERSTORM WATCH
WILL LIKELY BE NEEDED SOON.
DISCUSSION...THE ATMOSPHERE IS DESTABILIZING OVER WRN THROUGH CNTRL
MT WHERE TEMPERATURES ARE CLIMBING THROUGH THE 70S TO NEAR 80 F.
SUFFICIENT LOW-LEVEL MOISTURE EXISTS TO SUPPORT UPPER 40S TO NEAR
50F SFC DEWPOINTS WITHIN A WELL MIXED BOUNDARY LAYER...AND LATEST
OBJECTIVE ANALYSIS SHOWS MLCAPE AROUND 1000 J/KG OVER CNTRL MT.
STORMS ARE ALREADY BEGINNING TO DEVELOP OVER THE HIGHER TERRAIN AND
WILL LIKELY INTENSIFY DURING THE AFTERNOON AS THEY MOVE EWD INTO THE
UNSTABLE WARM SECTOR. EFFECTIVE BULK SHEAR WILL GRADUALLY INCREASE
TO 30-40 KT AS A MID-LEVEL JET DEVELOPS NEWD TOWARD SWRN MT. THUS
SOME STORMS MAY ACQUIRE MID-LEVEL UPDRAFT ROTATION WHICH /ALONG WITH
7-7.5 C/KM MID-LEVEL LAPSE RATES AND MODERATE INSTABILITY/ SHOULD
SUPPORT A THREAT FOR HAIL. INVERTED-V BOUNDARY LAYERS WILL ALSO
AUGMENT THE THREAT FOR A FEW DAMAGING WIND GUSTS AS STORMS MOVE OFF
THE MOUNTAINS.
..DIAL/MEAD.. 06/01/2015
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BYZ...GGW...TFX...MSO...
LAT...LON 45061050 45061211 45961217 46741253 47601257 47701032
47560762 46050699 45250850 45061050SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 1, 12:48 PM MDT | Mesoscale Discussion | SPC | Beaverhead, Gallatin, Madison, Park | 117 min |
| Jun 1, 2:19 PM MDT | Severe Thunderstorm Watch | SPC | Beaverhead, Broadwater, Carbon, Cascade, Fergus, Gallatin and 14 more | 7 hr |
| Jun 1, 2:41 PM MDT | Mesoscale Discussion | SPC | Fallon, Wibaux | 2 hr |
| Jun 1, 4:31 PM MDT | Mesoscale Discussion | SPC | Beaverhead, Broadwater, Carbon, Cascade, Fergus, Gallatin and 13 more | 59 min |
Nearby
Mesoscale Discussions in Montana, 2015Every mesoscale discussion in 2015
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.