Alert archive / Montana / Mesoscale Discussions in 2011
Mesoscale Discussion 1613
The Storm Prediction Center issued this mesoscale discussion at Jul 14, 2011, 11:04 AM MDT for 11 counties in Montana. It was in force for 116 min.
The area
The outline as issued.
The facts
- Issued
- Jul 14, 2011, 11:04 AM MDT (17:04 UTC)
- Expired
- Jul 14, 2011, 1:00 PM MDT
- In force
- 116 min
- Issued by
- the Storm Prediction Center
Counties Blaine County, MT, Fergus County, MT, Golden Valley County, MT, Judith Basin County, MT, Meagher County, MT, Musselshell County, MT, Petroleum County, MT, Phillips County, MT, Stillwater County, MT, Sweet Grass County, MT, Wheatland County, MT
The radar
The Great Falls radar (KTFX), 159 km from the middle of the area, began a volume at 17:08 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, 5.1 hours before the alert went out and 101 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
- 88 J/kg
- Mixed-layer CIN
- -148 J/kg
- Mixed-layer LCL
- 1371 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- -25 m²/s²
- 0-3 km storm-relative helicity
- 88 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
The text
As transmitted, in the capitals the NWS used until 2016.
753
ACUS11 KWNS 141704
SWOMCD
SPC MCD 141704
MTZ000-141900-
MESOSCALE DISCUSSION 1613
NWS STORM PREDICTION CENTER NORMAN OK
1204 PM CDT THU JUL 14 2011
AREAS AFFECTED...CNTRL MT
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 141704Z - 141900Z
A WATCH LIKELY WILL BE NEEDED AT SOME POINT THIS AFTERNOON. CURRENT
INDICATIONS ARE THIS MAY BE CLOSER TO 20Z...BUT AN ISOLATED SEVERE
THREAT MAY DEVELOP EARLIER.
LOW-LEVEL LAPSE RATES ARE BEGINNING TO STEEPEN WITH INSOLATION...
AND AT LEAST POCKETS OF MODERATE BOUNDARY LAYER CAPE UP TO AROUND
1000+ J/KG APPEAR POSSIBLE WITHIN THE NEXT COUPLE OF HOURS... BEFORE
BECOMING MORE WIDESPREAD TOWARD THE 20-22Z TIME FRAME. AS A
RESULT...RECENT INTENSIFYING TRENDS TO A STORM WEST/NORTHWEST OF
LEWISTOWN PROBABLY WILL CONTINUE. ON THE EDGE OF A BELT OF 40-50+
KT SOUTHWESTERLY 500 MB FLOW...VERTICAL SHEAR IS ALREADY SUFFICIENT
FOR SUPERCELLS...AND THE RISK FOR SEVERE HAIL/WIND COULD INCREASE
ACROSS PARTS OF NORTH CENTRAL MONTANA AS EARLY AS 18-19Z. A MORE
SUBSTANTIVE OR WIDESPREAD SEVERE WEATHER THREAT... THOUGH...IS STILL
NOT EXPECTED UNTIL LATER THIS AFTERNOON...AIDED BY BETTER FORCING
ASSOCIATED WITH UPSTREAM CLOSED LOW/UPPER TROUGH GRADUALLY LIFTING
INTO ALBERTA/SASKATCHEWAN.
..KERR.. 07/14/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BYZ...GGW...TFX...
LAT...LON 47071084 48171015 48960963 48900758 48640684 47200724
45390891 45170987 45881107 47071084SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 13, 7:33 PM MDT | Mesoscale Discussion | SPC | Blaine, Cascade, Chouteau, Fergus, Flathead, Glacier and 8 more | 57 min |
| Jul 14, 1:56 PM MDT | Severe Thunderstorm Watch | SPC | Big Horn, Blaine, Carbon, Carter, Custer, Daniels and 23 more | 9 hr |
Nearby
Mesoscale Discussions in Montana, 2011Every mesoscale discussion in 2011
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.