Alert archive / Montana / Severe Thunderstorm Warnings in 2010

Severe Thunderstorm Warning 22, NWS Missoula, MT

July 31, 2010Ravalli County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Jul 31, 2010, 1:33 PM MDT for Ravalli County, Montana. It was in force for 42 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 31, 2010, 1:33 PM MDT (19:33 UTC)
Expired: Jul 31, 2010, 2:15 PM MDT
In force: 42 min
Issued by: NWS Missoula, MT
Area: Storm-based polygon

County Ravalli County, MT

The radar

The Missoula radar (KMSX), 107 km from the middle of the area, began a volume at 19:34 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 31, 1:19 PM MDT	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Spokane, WA (KOTX), launched 12:00Z, 7.6 hours before the alert went out and 250 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: 69 J/kg
Mixed-layer CIN: -264 J/kg
Mixed-layer LCL: 2380 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 34 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Missoula, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 31, 8:35 AM MDT, 4 hours 58 minutes earlier.

Area forecast discussion, Jul 31, 8:35 AM MDT, 4 hours 58 minutes before

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Hazardous weather outlook, Jul 31, 1:34 AM MDT, 11 hours 59 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MISSOULA MT
134 AM MDT SAT JUL 31 2010

IDZ005>010-MTZ001>007-043-010000-
NORTHERN CLEARWATER MOUNTAINS-SOUTHERN CLEARWATER MOUNTAINS-
OROFINO/GRANGEVILLE REGION-LOWER HELLS CANYON/SALMON RIVER REGION-
WESTERN LEMHI COUNTY-EASTERN LEMHI COUNTY-KOOTENAI/CABINET REGION-
WEST GLACIER REGION-FLATHEAD/MISSION VALLEYS-
LOWER CLARK FORK REGION-MISSOULA/BITTERROOT VALLEYS-
BITTERROOT/SAPPHIRE MOUNTAINS-BUTTE/BLACKFOOT REGION-
POTOMAC/SEELEY LAKE REGION-
134 AM MDT SAT JUL 31 2010 /1234 AM PDT SAT JUL 31 2010/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
IDAHO...NORTHWEST MONTANA AND WEST CENTRAL MONTANA.

.DAY ONE...TODAY

THUNDERSTORMS WILL INCREASE IN COVERAGE AND INTENSITY ACROSS THE
AREA THROUGH SATURDAY EVENING. SOME OF THESE STORMS MAY BE SEVERE
WITH LARGE HAIL AND DAMAGING WINDS POSSIBLE. THE GREATEST THREAT
FOR SEVERE STORMS WILL BE DURING SATURDAY AFTERNOON AND EVENING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

NO HAZARDOUS WEATHER IS CURRENTLY EXPECTED.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

GIBSON

In the hours before

Local storm report, Jul 31, 8:16 AM MDT, 5 hours 17 minutes before

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Special weather statement, Jul 31, 11:32 AM MDT, 2 hours 1 minute before

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Special weather statement, Jul 31, 1:02 PM MDT, 31 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 30, 6:27 PM MDT	Special Weather Statement	MSO	Granite	48 min
Jul 30, 8:34 PM MDT	Special Weather Statement	MSO		26 min
Jul 30, 9:09 PM MDT	Special Weather Statement	MSO	Missoula	51 min
Jul 31, 2:12 AM MDT	Special Weather Statement	MSO	Missoula	63 min
Jul 31, 1:02 PM MDT	Special Weather Statement	MSO	Deer Lodge, Ravalli	58 min
Jul 31, 2:05 PM MDT	Special Weather Statement	MSO	Deer Lodge, Granite, Silver Bow	40 min
Jul 31, 2:41 PM MDT	Special Weather Statement	MSO		34 min
Jul 31, 2:58 PM MDT	Special Weather Statement	MSO	Powell	32 min
Jul 31, 3:09 PM MDT	Special Weather Statement	MSO	Missoula	36 min
Jul 31, 3:21 PM MDT	Special Weather Statement	MSO		39 min
Jul 31, 3:32 PM MDT	Special Weather Statement	MSO	Missoula	28 min
Jul 31, 4:01 PM MDT	Special Weather Statement	MSO	Missoula	29 min
Jul 31, 4:28 PM MDT	Special Weather Statement	MSO	Missoula	32 min
Jul 31, 5:25 PM MDT	Special Weather Statement	MSO	Lake	35 min
Jul 31, 5:31 PM MDT	Severe Thunderstorm Warning	MSO	Flathead, Lake, Sanders	29 min
Jul 31, 5:34 PM MDT	Special Weather Statement	MSO	Missoula	26 min
Jul 31, 11:32 AM MDT	Special Weather Statement	MSO	Lemhi	73 min
Jul 31, 4:54 PM MDT	Severe Thunderstorm Warning	MSO	Idaho	36 min
Jul 31, 5:25 PM MDT	Severe Thunderstorm Warning	MSO	Clearwater, Idaho	50 min

Nearby

Severe Thunderstorm Warnings in Montana, 2010 Every severe thunderstorm warning in 2010

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.