Alert archive / Montana / Mesoscale Discussions in 2005
Mesoscale Discussion 1421
The Storm Prediction Center issued this mesoscale discussion at Jun 21, 2005, 9:32 PM MDT for 9 counties in Montana. It was in force for 58 min.
The area
The outline as issued.
The facts
- Issued
- Jun 21, 2005, 9:32 PM MDT (03:32 UTC)
- Expired
- Jun 21, 2005, 10:30 PM MDT
- In force
- 58 min
- Issued by
- the Storm Prediction Center
Counties Cascade County, MT, Chouteau County, MT, Hill County, MT, Lewis and Clark County, MT, Liberty County, MT, Pondera County, MT, Powell County, MT, Teton County, MT, Toole County, MT
The radar
The Great Falls radar (KTFX), 34 km from the middle of the area, began a volume at 03:35 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, 3.5 hours before the alert went out and 71 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
- 693 J/kg
- Mixed-layer CIN
- -101 J/kg
- Mixed-layer LCL
- 3085 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 167 m²/s²
- 0-3 km storm-relative helicity
- 182 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 3.1
The text
As transmitted, in the capitals the NWS used until 2016.
000 ACUS11 KWNS 220333 SWOMCD SPC MCD 220332 MTZ000-220430- MESOSCALE DISCUSSION 1421 NWS STORM PREDICTION CENTER NORMAN OK 1032 PM CDT TUE JUN 21 2005 AREAS AFFECTED...SWRN THROUGH N CNTRL MT CONCERNING...SEVERE THUNDERSTORM WATCH 510... VALID 220332Z - 220430Z THREAT OF ISOLATED DAMAGING WIND AND HAIL MIGHT PERSIST FOR A COUPLE HOURS FROM SWRN THROUGH N CNTRL MT. OVERALL DURATION AND MAGNITUDE OF THE THREAT DOES NOT APPEAR SUFFICIENT FOR ANOTHER WW. FORCING FOR ASCENT ASSOCIATED WITH A SHORTWAVE TROUGH MOVING NEWD THROUGH THE NRN ROCKIES HAS CONTRIBUTED TO AN INCREASE IN COVERAGE OF THUNDERSTORMS OVER WRN MT THIS EVENING. RELATIVELY LARGE BOUNDARY LAYER TEMPERATURE-DEWPOINT SPREADS ARE ENHANCING THE POTENTIAL FOR DAMAGING WIND WITH THE STRONGER STORMS. MID LEVEL FLOW WILL VEER AND STRENGTHEN OVER WRN MT IN WAKE OF THE SHORTWAVE TROUGH...AND THIS SHOULD ENHANCE THE DOWNSLOPE POTENTIAL IN THE LEE OF THE MOUNTAINS. ISOLATED STORMS MIGHT REMAIN SEVERE FOR AN HOUR OR TWO BEYOND THE EXPIRATION OF WW 510. HOWEVER...INCREASING DOWNSLOPE POTENTIAL AND COOLING BOUNDARY LAYER SHOULD SERVE AS LIMITING FACTORS FOR A LONGER TERMED SEVERE THREAT. ..DIAL.. 06/22/2005 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...TFX...MSO... 47321018 46021288 48321380 48891209 48710947
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 21, 6:32 PM MDT | Mesoscale Discussion | SPC | Custer, Garfield, McCone, Petroleum, Phillips, Prairie and 2 more | 88 min |
| Jun 21, 7:00 PM MDT | Severe Thunderstorm Watch | SPC | Custer, Daniels, Dawson, Fallon, Garfield, McCone and 11 more | 7 hr |
| Jun 21, 10:26 PM MDT | Mesoscale Discussion | SPC | Custer, Daniels, Dawson, Fallon, Garfield, McCone and 9 more | 64 min |
| Jun 22, 1:15 AM MDT | Mesoscale Discussion | SPC | Carter, Custer, Daniels, Dawson, Fallon, Garfield and 14 more | 60 min |
| Jun 22, 2:50 PM MDT | Mesoscale Discussion | SPC | Blaine, Broadwater, Cascade, Chouteau, Fergus, Gallatin and 15 more | 115 min |
| Jun 22, 3:50 PM MDT | Severe Thunderstorm Watch | SPC | Blaine, Broadwater, Cascade, Chouteau, Daniels, Fergus and 20 more | 7 hr |
Nearby
Mesoscale Discussions in Montana, 2005Every mesoscale discussion in 2005
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.