Alert archive / Montana / Mesoscale Discussions in 2003

Mesoscale Discussion 1122

May 25, 200314 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at May 25, 2003, 5:13 PM MDT for 14 counties in Montana. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: May 25, 2003, 5:13 PM MDT (23:13 UTC)
Expired: May 25, 2003, 6:45 PM MDT
In force: 92 min
Issued by: the Storm Prediction Center

Counties Broadwater County, MT, Cascade County, MT, Deer Lodge County, MT, Gallatin County, MT, Granite County, MT, Jefferson County, MT, Lewis and Clark County, MT, Madison County, MT, Meagher County, MT, Missoula County, MT, Pondera County, MT, Powell County, MT, Silver Bow County, MT, Teton County, MT

The radar

The Great Falls radar (KTFX), 82 km from the middle of the area, began a volume at 23:15 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 12:00Z, 11.2 hours before the alert went out and 126 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 42 J/kg
Mixed-layer CIN: -374 J/kg
Mixed-layer LCL: 2151 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -13 m²/s²
0-3 km storm-relative helicity: 17 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

967 
ACUS11 KWNS 252313
SWOMCD
SPC MCD 252313 
MTZ000-260045-

MESOSCALE DISCUSSION 1122
NWS STORM PREDICTION CENTER NORMAN OK
0613 PM CDT SUN MAY 25 2003

AREAS AFFECTED...NWRN MT

CONCERNING...SEVERE THUNDERSTORM WATCH 432...

VALID 252313Z - 260045Z

STRONG TO INTENSE CONVECTION ALONG PRIMARY FRONTAL BAND APPEARS TO
BE DEVELOPING EWD ACROSS LAKE AND FLATHEAD COUNTIES OF NW MT ATTM
AND MAY INTENSIFY FURTHER AS STORMS MOVES TOWARD AXIS OF GREATER
INSTABILITY /MLCAPE 1000-1500 J/KG/ SITUATED ACROSS MISSOULA...
POWELL...AND ERN FLATHEAD COUNTIES. LINEAR FORCING ALONG THE FRONTAL
ZONE...AND SHEAR VECTORS ORIENTED PARALLEL TO THE FRONT SUGGEST THE
POTENTIAL FOR SMALL SCALE BOWS PRODUCING DAMAGING WINDS. IN
ADDITION...MAGNITUDE OF INSTABILITY AND SHEAR COUPLED WITH LOW WBZ
LEVELS INDICATE A CONTINUING THREAT OF LARGE HAIL.

MORE ISOLD STORMS WERE OCCURRING WITHIN LEE/THERMAL TROUGH EAST OF
THE MAIN SYNOPTIC FRONT. THE STRONGEST OF THESE STORMS WAS OVER
PONDERA/TOOLE COUNTIES AND APPEARS TO HAVE SUPERCELL STRUCTURE
DESPITE WEAKER DEEP LAYER SHEAR. THIS PARTICULAR CELL WAS MOVING
NEWD AT ABOUT 20KT AND TFX VWP DATA SUGGESTS STRONG DIRECTIONAL
SHEAR IN THE UPDRAFT SOURCE REGION CONTRIBUTING TO AN ENHANCED
HODOGRAPHS INDICATIVE OF HIGHER POTENTIAL FOR LOW LEVEL STORM
ROTATION.

..CARBIN.. 05/25/2003

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

ATTN...WFO...BYZ...TFX...MSO...

48051062 45641078 44691213 45901393 48871404

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 25, 1:28 PM MDT	Mesoscale Discussion	SPC	Beaverhead, Big Horn, Broadwater, Carbon, Cascade, Deer Lodge and 22 more	3 hr
May 25, 3:00 PM MDT	Severe Thunderstorm Watch	SPC	Broadwater, Cascade, Chouteau, Flathead, Glacier, Judith Basin and 9 more	5 hr

Nearby

Mesoscale Discussions in Montana, 2003 Every 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.