Alert archive / Montana / Mesoscale Discussions in 2016
Mesoscale Discussion 1503
The Storm Prediction Center issued this mesoscale discussion at Aug 9, 2016, 5:35 PM MDT for 20 counties in Montana. It was in force for 85 min.
The area
The outline as issued.
The facts
- Issued
- Aug 9, 2016, 5:35 PM MDT (23:35 UTC)
- Expired
- Aug 9, 2016, 7:00 PM MDT
- In force
- 85 min
- Issued by
- the Storm Prediction Center
Counties Blaine County, MT, Broadwater County, MT, Cascade County, MT, Chouteau County, MT, Fergus County, MT, Garfield County, MT, Golden Valley County, MT, Hill County, MT, Judith Basin County, MT, Lewis and Clark County, MT, Liberty County, MT, Meagher County, MT, Musselshell County, MT, Petroleum County, MT, Phillips County, MT, Pondera County, MT, Teton County, MT, Toole County, MT, Valley County, MT, Wheatland County, MT
The radar
The Great Falls radar (KTFX), 109 km from the middle of the area, began a volume at 23:37 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, 11.6 hours before the alert went out and 52 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
- 195 J/kg
- Mixed-layer CIN
- -253 J/kg
- Mixed-layer LCL
- 1229 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- 59 m²/s²
- 0-3 km storm-relative helicity
- 288 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
791
ACUS11 KWNS 092335
SWOMCD
SPC MCD 092335
MTZ000-100100-
MESOSCALE DISCUSSION 1503
NWS STORM PREDICTION CENTER NORMAN OK
0635 PM CDT TUE AUG 09 2016
AREAS AFFECTED...PORTIONS OF MONTANA
CONCERNING...SEVERE THUNDERSTORM WATCH 436...
VALID 092335Z - 100100Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 436
CONTINUES.
SUMMARY...A FEW SEVERE THUNDERSTORMS SHOULD DEVELOP EASTWARD THIS
EVENING...WITH AN ATTENDANT THREAT FOR LARGE HAIL /POTENTIALLY OVER
2 INCHES/ AND DAMAGING WINDS.
DISCUSSION...IN RESPONSE TO MID-LEVEL HEIGHT FALLS AND
TERRAIN-INDUCED CIRCULATIONS...STRONG TO OCCASIONALLY SEVERE
THUNDERSTORMS HAVE ORGANIZED ACROSS WEST-CENTRAL MONTANA OVER THE
LAST FEW HOURS. AS MID-LEVEL COOLING SPREADS NORTHEAST THIS
EVENING...CONVECTION SHOULD CONTINUE TO INTENSIFY FARTHER EAST OVER
CENTRAL MT...AIDED BY INCREASING LOW-LEVEL STORM-RELATIVE INFLOW AND
STRENGTHENING WARM-AIR ADVECTION.
GGW AND BLX VWP DATA EXHIBIT AMPLE DEEP-LAYER SHEAR FOR UPDRAFT
ORGANIZATION...AS VIGOROUS MID-LEVEL SOUTHWESTERLIES OVERLIE
LOW-LEVEL EASTERLIES. MOREOVER...FAIRLY STRAIGHT MID-LEVEL
HODOGRAPHS SUGGEST THE POTENTIAL FOR A FEW SPLITTING CELLS AND/OR
BOWING SEGMENTS WHICH WOULD ENHANCE THE DAMAGING WIND POTENTIAL.
STORMS MAY BECOME ROOTED ABOVE A STABLE SFC LAYER LATER THIS EVENING
AS TEMPS COOL...BUT STEEP MID-LEVEL LAPSE RATES AND THE
AFOREMENTIONED STRONG SHEAR WILL LIKELY MAINTAIN A POTENTIAL FOR
LARGE HAIL GROWTH IN ROTATING UPDRAFTS.
..PICCA.. 08/09/2016
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BYZ...GGW...TFX...
LAT...LON 46221142 46060893 46460644 47610580 48670637 48841167
48611278 47511292 46621191 46221142SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 9, 2:19 PM MDT | Mesoscale Discussion | SPC | Broadwater, Cascade, Chouteau, Deer Lodge, Granite, Jefferson and 8 more | 116 min |
| Aug 9, 3:51 PM MDT | Mesoscale Discussion | SPC | Carter, Custer, Fallon, Powder River | 114 min |
| Aug 9, 4:16 PM MDT | Severe Thunderstorm Watch | SPC | Carter, Custer, Fallon, Powder River | 7 hr |
| Aug 9, 4:53 PM MDT | Severe Thunderstorm Watch | SPC | Blaine, Cascade, Chouteau, Fergus, Garfield, Glacier and 12 more | 7 hr |
Nearby
Mesoscale Discussions in Montana, 2016Every mesoscale discussion in 2016
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.