Alert archive / Montana / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 2, NWS Missoula, MT

May 6, 2017Deer Lodge County, Granite County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at May 6, 2017, 2:22 PM MDT for Deer Lodge County, Granite County, Montana. It was in force for 23 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
May 6, 2017, 2:22 PM MDT (20:22 UTC)
Expired
May 6, 2017, 2:45 PM MDT
In force
23 min
Issued by
NWS Missoula, MT
Area
Storm-based polygon

Counties Deer Lodge County, MT, Granite County, MT

The radar

The Missoula radar (KMSX), 110 km from the middle of the area, began a volume at 20:22 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.

What was reported inside it

TimeReportWhereRemark
May 6, 2:30 PM MDTHAIL 18 Wsw Georgetown, MTRESIDENT REPORTED GROUND COVERED WHITE WITH QUARTER-SIZED HAIL. A FEW STRIKES OF LIGHTNING ACCOMPANIED THE STORM.
May 6, 2:42 PM MDTHAIL 1.251 W Georgetown, MTTRAINED SPOTTERS ESTIMATED QUARTER AND HALF DOLLAR SIZED HAIL STONES. THEY WERE WORRIED ABOUT VEHICLE DAMAGE. DID NOT GO OUTSIDE YET TO CHECK VEHICLES.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 8.4 hours before the alert went out and 258 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, Great_falls, MT at 12:00Z on 2017-05-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 12:00Z on 2017-05-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -30 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1696 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
-30 m²/s²
0-3 km storm-relative helicity
166 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

903 
WUUS55 KMSO 062022
SVRMSO
MTC023-039-062045-
/O.NEW.KMSO.SV.W.0002.170506T2022Z-170506T2045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Missoula MT
222 PM MDT SAT MAY 6 2017

The National Weather Service in Missoula has issued a

* Severe Thunderstorm Warning for...
  North central Deer Lodge County in west central Montana...
  Southeastern Granite County in west central Montana...

* Until 245 PM MDT

* At 221 PM MDT, Doppler radar indicated a severe thunderstorm 
  capable of producing quarter size hail, heavy rain, and damaging 
  winds in excess of 60 mph. This storm was located 18 miles 
  southwest of Philipsburg, or 27 miles west of Anaconda, and moving 
  northeast at 35 mph.

* Locations impacted include...
  Philipsburg, Georgetown and Porters Corner. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

In addition to large hail and damaging winds, continuous cloud to
ground lightning is occurring with this storm. Move indoors
immediately. Lightning is one of nature's leading killers. Remember,
if you can hear thunder, you are close enough to be struck by
lightning.

&&

LAT...LON 4598 11351 4610 11369 4645 11332 4619 11294
TIME...MOT...LOC 2021Z 223DEG 32KT 4611 11352 

$$
2 follow-up statements
239 
WWUS55 KMSO 062037
SVSMSO

Severe Weather Statement
National Weather Service Missoula MT
237 PM MDT SAT MAY 6 2017

MTC023-039-062045-
/O.CON.KMSO.SV.W.0002.000000T0000Z-170506T2045Z/
Deer Lodge MT-Granite MT-
237 PM MDT SAT MAY 6 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM MDT
FOR NORTH CENTRAL DEER LODGE AND SOUTHEASTERN GRANITE COUNTIES...

At 237 PM MDT, Doppler radar indicated a severe thunderstorm capable
of producing quarter size hail and damaging winds in excess of 60
mph. This storm was located 9 miles southwest of Philipsburg, or 21
miles west of Anaconda, moving northeast at 35 mph.

Locations impacted include...
Philipsburg, Georgetown and Porters Corner. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you are in the path of this storm, prepare immediately for large
hail and damaging winds. People outside should move to a shelter,
preferably inside a strong building and away from windows.

In addition to large hail and damaging winds, continuous cloud to
ground lightning is occurring with this storm.  Move indoors
immediately. Lightning is one of nature's leading killers. Remember,
if you can hear thunder, you are close enough to be struck by
lightning.

&&

LAT...LON 4602 11343 4615 11364 4642 11335 4616 11301
TIME...MOT...LOC 2037Z 223DEG 32KT 4621 11338 

$$
766 
WWUS55 KMSO 062045
SVSMSO

Severe Weather Statement
National Weather Service Missoula MT
245 PM MDT SAT MAY 6 2017

MTC023-039-062053-
/O.EXP.KMSO.SV.W.0002.000000T0000Z-170506T2045Z/
Deer Lodge MT-Granite MT-
245 PM MDT SAT MAY 6 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL DEER LODGE AND
SOUTHEASTERN GRANITE COUNTIES WILL EXPIRE AT 245 PM MDT...
        
Remember, another Severe Thunderstorm Warning still remains in 
effect for NORTH CENTRAL DEER LODGE and SOUTHEASTERN GRANITE 
COUNTIES until 3:15pm MDT.

LAT...LON 4602 11343 4615 11364 4642 11335 4616 11301
TIME...MOT...LOC 2043Z 223DEG 32KT 4625 11333 

$$

The office that day

Everything else NWS Missoula, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 5, 6:34 PM MDTSpecial Weather StatementMSODeer Lodge71 min
May 5, 6:57 PM MDTSpecial Weather StatementMSOMissoula48 min
May 5, 7:39 PM MDTSpecial Weather StatementMSOSanders51 min
May 5, 7:52 PM MDTSpecial Weather StatementMSOLincoln68 min
May 6, 12:11 PM MDTSpecial Weather StatementMSO49 min
May 6, 12:55 PM MDTSpecial Weather StatementMSORavalli50 min
May 6, 1:26 PM MDTSevere Thunderstorm WarningMSORavalli34 min
May 6, 2:07 PM MDTSpecial Weather StatementMSODeer Lodge23 min
May 6, 2:31 PM MDTSpecial Weather StatementMSOSilver Bow44 min
May 6, 2:42 PM MDTSevere Thunderstorm WarningMSODeer Lodge, Granite33 min
May 6, 3:16 PM MDTSevere Thunderstorm WarningMSOPowell29 min
May 6, 3:41 PM MDTSevere Thunderstorm WarningMSOPowell34 min

Nearby

Severe Thunderstorm Warnings in Montana, 2017Every severe thunderstorm warning in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.