Alert archive / Montana / Mesoscale Discussions in 2012

Mesoscale Discussion 1082

June 5, 2012Chouteau County, Liberty County, Toole County, Montana

The Storm Prediction Center issued this mesoscale discussion at Jun 5, 2012, 9:49 PM MDT for Chouteau County, Liberty County, Toole County, Montana. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Jun 5, 2012, 9:49 PM MDT (03:49 UTC)
Expired
Jun 5, 2012, 10:45 PM MDT
In force
56 min
Issued by
the Storm Prediction Center

Counties Chouteau County, MT, Liberty County, MT, Toole County, MT

The radar

The Great Falls radar (KTFX), 90 km from the middle of the area, began a volume at 03:51 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, 3.8 hours before the alert went out and 312 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.

Skew-T log-pSkew-T log-p diagram, Glasgow Intl Airport, MT at 00:00Z on 2012-06-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 880 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Glasgow Intl Airport, MT at 00:00Z on 2012-06-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 244 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
880 J/kg
Mixed-layer CIN
-226 J/kg
Mixed-layer LCL
2578 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
244 m²/s²
0-3 km storm-relative helicity
359 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

527 
ACUS11 KWNS 060349
SWOMCD
SPC MCD 060349 
MTZ000-060445-

MESOSCALE DISCUSSION 1082
NWS STORM PREDICTION CENTER NORMAN OK
1049 PM CDT TUE JUN 05 2012

AREAS AFFECTED...N-CNTRL MT

CONCERNING...TORNADO WATCH 360...

VALID 060349Z - 060445Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 360 CONTINUES.

SUMMARY...WW 360 IS SCHEDULED TO EXPIRE AT 05Z. ALTHOUGH THE TORNADO
THREAT APPEARS TO HAVE BECOME MINIMAL...A RISK FOR MARGINALLY SEVERE
HAIL MAY PERSIST WITH POST-FRONTAL CONVECTION JUST E OF THE I-15
CORRIDOR. NEW WW ISSUANCE IS NOT ANTICIPATED.

DISCUSSION...SEVERE-PRODUCING SUPERCELLS THAT TRACKED ACROSS ERN
PORTIONS OF WW 360 EARLIER THIS EVENING HAVE NOW CROSSED INTO
ALBERTA. STILL...STRONG CONVECTION PERSISTS TO THE WEST OF THE
COMPOSITE FRONT/OUTFLOW THAT EXTENDS FROM AROUND 20 W HVR TO 20 E
LWT. 40-50 KT EFFECTIVE SHEAR WILL REMAIN SUFFICIENT FOR MARGINALLY
SEVERE HAIL WITH THE MORE INTENSE CORES UNTIL CONVECTION ULTIMATELY
PROGRESSES N INTO ALBERTA.

..GRAMS.. 06/06/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...TFX...

LAT...LON   49091043 48561045 47571010 47241014 47091040 47281119
            48631211 48991204 49091043

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 5, 6:07 PM MDTMesoscale DiscussionSPCHill, Judith Basin53 min
Jun 5, 7:39 PM MDTMesoscale DiscussionSPCBroadwater66 min
Jun 5, 8:08 PM MDTMesoscale DiscussionSPCBlaine, Cascade, Chouteau, Hill, Liberty, Pondera and 2 more67 min

Nearby

Mesoscale Discussions in Montana, 2012Every mesoscale discussion in 2012

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.