Alert archive / Montana / Mesoscale Discussions in 2011
Mesoscale Discussion 1749
The Storm Prediction Center issued this mesoscale discussion at Jul 26, 2011, 1:07 PM MDT for 13 counties in Montana; 5 counties in North Dakota. It was in force for 53 min.
The area
The outline as issued.
The facts
- Issued
- Jul 26, 2011, 1:07 PM MDT (19:07 UTC)
- Expired
- Jul 26, 2011, 2:00 PM MDT
- In force
- 53 min
- Issued by
- the Storm Prediction Center
Counties Daniels County, MT, Dawson County, MT, Fallon County, MT, Garfield County, MT, McCone County, MT, Petroleum County, MT, Phillips County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Valley County, MT, Wibaux County, MT, Billings County, ND, Divide County, ND, Golden Valley County, ND, McKenzie County, ND, Williams County, ND
The radar
The Glasgow radar (KGGW), 121 km from the middle of the area, began a volume at 19:06 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
Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 7.1 hours before the alert went out and 121 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 0 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- -88 m²/s²
- 0-3 km storm-relative helicity
- -31 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.3
The text
As transmitted, in the capitals the NWS used until 2016.
554
ACUS11 KWNS 261908
SWOMCD
SPC MCD 261907
NDZ000-MTZ000-262000-
MESOSCALE DISCUSSION 1749
NWS STORM PREDICTION CENTER NORMAN OK
0207 PM CDT TUE JUL 26 2011
AREAS AFFECTED...MT...ND
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 261907Z - 262000Z
THERE HAS BEEN A RECENT INCREASE IN ISOLATED STORMS ON APPARENT COLD
FRONT/OUTFLOW/LEE-TROUGH INTERSECTION IN PHILLIPS COUNTY IN NERN MT.
THIS ACTIVITY WILL TRACK EAST INTO A MOIST AND UNSTABLE AIRMASS OVER
NERN MT AND WRN ND WHERE A WATCH MAY BE NEEDED LATER THIS AFTERNOON.
MODEST MID LEVEL HEIGHT FALLS WILL ACCOMPANY A SHORT WAVE TROUGH
SPREADING EAST ACROSS NRN MT LATER TODAY. ASSOCIATED COLD FRONT AND
DEVELOPING LEE LOW COULD CONTINUE TO AID IN TSTM DEVELOPMENT AS THE
UPPER TROUGH MOVES EAST. GREATEST INSTABILITY CURRENTLY EXISTS ALONG
A CORRIDOR FROM GGW TO SDY TO DIK. LATEST OBJECTIVE DATA INDICATES
THAT CAPPING REMAINS STRONG WITHIN THIS CORRIDOR. HOWEVER...EARLIER
GGW RAOB ADJUSTED FOR CURRENT SURFACE CONDITIONS SUGGESTS THAT CAP
IS GRADUALLY WEAKENING. FORCING WITH THE FRONT/LOW AND LARGER SCALE
ASCENT SHOULD AID IN REDUCING INHIBITION OVER THE NEXT FEW HOURS
WITH AN INCREASING CHANCE FOR SURFACE-BASED STORMS.
THERE REMAINS SOME UNCERTAINTY REGARDING STORM COVERAGE ACROSS NERN
MT WITH VERY LITTLE QPF/REFLECTIVITY INDICATED IN STORM SCALE
MODELS. IF CAPPING/INHIBITION CAN BE OVERCOME AND STORMS INCREASE IN
AREAL COVERAGE AND INTENSITY...STRENGTHENING FORCING AND SHEAR WOULD
SUPPORT A WATCH BEING ISSUED.
..CARBIN.. 07/26/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BIS...BYZ...GGW...TFX...
LAT...LON 46190456 46490664 46900847 47470862 48290836 48870783
48910637 48840303 48150264 47670268 47230279 46700297
46190456SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 25, 9:07 PM MDT | Mesoscale Discussion | SPC | Dawson, McCone, Prairie | 83 min |
| Jul 26, 9:45 AM MDT | Mesoscale Discussion | SPC | Roosevelt, Sheridan | 60 min |
| Jul 26, 2:43 PM MDT | Severe Thunderstorm Watch | SPC | Daniels, Dawson, Garfield, McCone, Petroleum, Prairie and 5 more | 5 hr |
| Jul 26, 2:59 PM MDT | Mesoscale Discussion | SPC | Dickey, Emmons, LaMoure, Logan, McIntosh, Sargent and 1 more | 2 hr |
| Jul 26, 4:21 PM MDT | Tornado Watch | SPC | Dickey, Emmons, LaMoure, Logan, McIntosh, Sioux | 5 hr |
Nearby
Mesoscale Discussions in Montana, 2011Mesoscale Discussions in North Dakota, 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.