Alert archive / Montana / Mesoscale Discussions in 2003
Mesoscale Discussion 2121
The Storm Prediction Center issued this mesoscale discussion at Aug 7, 2003, 9:11 PM MDT for 13 counties in Montana. It was in force for 64 min.
The area
The outline as issued.
The facts
- Issued
- Aug 7, 2003, 9:11 PM MDT (03:11 UTC)
- Expired
- Aug 7, 2003, 10:15 PM MDT
- In force
- 64 min
- Issued by
- the Storm Prediction Center
Counties Blaine County, MT, Daniels County, MT, Dawson County, MT, Garfield County, MT, Hill County, MT, McCone County, MT, Phillips County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Valley County, MT, Wibaux County, MT
The radar
The Glasgow radar (KGGW), 97 km from the middle of the area, began a volume at 03:13 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, 3.2 hours before the alert went out and 99 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
- 2102 J/kg
- Mixed-layer CIN
- -86 J/kg
- Mixed-layer LCL
- 1972 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 18 m²/s²
- 0-3 km storm-relative helicity
- 75 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.2
The text
As transmitted, in the capitals the NWS used until 2016.
704 ACUS11 KWNS 080311 SWOMCD SPC MCD 080311 MTZ000-080415- MESOSCALE DISCUSSION 2121 NWS STORM PREDICTION CENTER NORMAN OK 1011 PM CDT THU AUG 07 2003 AREAS AFFECTED...NERN MT CONCERNING...SEVERE THUNDERSTORM WATCH 850... VALID 080311Z - 080415Z WS850 WILL EXPIRE AT 0400 UTC AND ANOTHER WW IS NOT ANTICIPATED. TSTMS CROSSING NRN/NERN MT HAVE BEEN WEAKENING THE PAST COUPLE OF HOURS WITH THE STRONGEST CELL MOVING THROUGH NRN ROSEBUD COUNTY. APPARENTLY...THE CAPPING NOTED ON THE 00 UTC GGW SOUNDING HAS INCREASED AND HAS BEEN DETRIMENTAL IN SUSTAINING WIDESPREAD SEVERE CONVECTION. DEEP LAYER SHEAR REMAINS SUPPORTIVE OF SUPERCELLS AND ONE OR TWO TSTMS MAY CONTINUE TO PRODUCE SEVERE WIND GUSTS AND HAIL ACROSS EXTREME NERN MT. HOWEVER...GIVEN THE DECREASE IN INTENSITY AND COVERAGE OF THE SEVERE THREAT...WS850 WILL BE ALLOWED TO EXPIRE WITH ANOTHER WW NOT ANTICIPATED. ..RACY.. 08/08/2003 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...GGW...BYZ...TFX... 46430678 47200731 47840790 48210865 48500987 48611084 49001100 49000417 46350408
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 1:48 PM MDT | Mesoscale Discussion | SPC | Dawson, Richland, Roosevelt, Sheridan, Wibaux | 117 min |
| Aug 8, 3:40 PM MDT | Severe Thunderstorm Watch | SPC | Dawson, Richland, Roosevelt, Sheridan, Wibaux | 6 hr |
| Aug 8, 4:35 PM MDT | Severe Thunderstorm Watch | SPC | Fergus, Garfield, Golden Valley, McCone, Musselshell, Petroleum and 1 more | 5 hr |
Nearby
Mesoscale Discussions in Montana, 2003Every mesoscale discussion in 2003
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.