Heavy Rain in Montana, July 12, 2011

Name: Heavy Rain in Montana, July 12, 2011
Start: 2011-07-12T18:57
End: 2011-07-12T19:25
Location: Montana

July 12, 2011 · NWS MSO · 1 event in 1 county or zone

A large closed low pressure system located off the Pacific Northwest coast pushed abundant moisture into northwest Montana.

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS MSO wrote it up.

A large closed low pressure system located off the Pacific Northwest coast pushed abundant moisture into northwest Montana.

What forecasters said that day

The local office's own words before the first event, 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 the first event at Jul 12, 1:34 PM MST, 5 hours 23 minutes earlier.

Area forecast discussion, Jul 12, 1:34 PM MST, 5 hours 23 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
234 PM MDT TUE JUL 12 2011

.DISCUSSION...SOUTHWESTERLY FLOW ALOFT HAS ALLOWED FOR SOME
MOISTURE TO STREAM INTO THE NORTHERN ROCKIES TODAY. THIS AFTERNOON
THE ATMOSPHERE HAS BEGAN TO DESTABILIZE ACROSS LEMHI COUNTY UP
INTO SOUTHWEST MONTANA AS A WEAK UPPER LEVEL JET MOVES INTO THE
REGION. THE COMBINATION OF MOISTURE AND UNSTABLE CONDITIONS WILL
ALLOW FOR THE DEVELOPMENT OF THUNDERSTORMS ESPECIALLY SOUTH AND
EAST OF A LINE FROM LOWELL IDAHO TO SEELEY LAKE MONTANA. A THESE STORMS
WILL BE CAPABLE OF PRODUCING HEAVY RAIN...LARGE HAIL AND
POTENTIALLY GUSTY WINDS..SO A SEVERE THUNDERSTORM WATCH HAS BEEN
ISSUED FOR THIS REGION. THE CONVECTION IS ANTICIPATED TO DIMINISH
DURING THE EVENING HOURS.

FOR WEDNESDAY THROUGH TUESDAY...NOT MANY CHANGES WERE MADE WITH
THIS ISSUANCE. MODELS CONTINUE TO SHOW A GENERAL COOL DOWN TO
ABOUT NORMAL TEMPERATURES OVER THE AREA FOR LATE THIS WEEK. THEN A
WARM UP FOR THE WEEKEND. FOR EARLY NEXT WEEK...LONGER RANGE
GUIDANCE IS COMING INTO AGREEMENT OF ANOTHER COOL FRONT MOVING IN
FROM THE PACIFIC OCEAN. CURRENT FORECAST MAY NEED TO BE COOLED
DOWN SOME IF SUBSEQUENT MODEL RUNS CONTINUE THE TREND.

&&

.AVIATION...SHORTWAVE ENERGY IS PASSING THROUGH SOUTHWEST MONTANA
THIS AFTERNOON AND ALONG WITH HIGH MOISTURE AND HAS ALLOWED FOR
SHOWERS AND THUNDERSTORMS TO DEVELOP. KBTM AND KSMN WILL SEE
THUNDERSTORMS MAINLY PRODUCING GUSTY WINDS AND HEAVY RAIN THROUGH
THIS AFTERNOON. WEST CENTRAL AND NORTHWEST MONTANA THUNDERSTORM
CHANCES WILL QUICKLY INCREASE LATER IN THE AFTERNOON WITH
THUNDERSTORMS HAVING THE POTENTIAL TO MAINTAIN INTO THE EVENING.
THUNDERSTORM ACTIVITY WILL DECREASE OVERNIGHT. MOIST AND UNSTABLE
CONDITIONS UNDER AND SOUTHWEST FLOW WILL AGAIN LEAD TO
THUNDERSTORM CHANCES WEDNESDAY AFTERNOON.

&&

NOTE: FLOOD WATCHES...WARNINGS AND ADVISORIES WILL NOT BE LISTED BELOW.

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
ID...NONE.
&&

SHORT TERM...SMITH
LONG TERM....GIBSON
AVIATION...KITSMILLER

In the hours before

Special weather statement, Jul 12, 6:14 PM MST, 43 minutes before

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Special weather statement, Jul 12, 6:52 PM MST, 5 minutes before

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The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 heavy rain. Local standard time, as filed.

Heavy Rain, Lincoln

When: July 12, 6:57 PM MST to 7:25 PM MST
Where: Lincoln County, 15 mi ENE of Libby
Reported by: Trained Spotter
Coordinates: 48.463, -115.228

A trained spotter reported one inch of rain in 30 minutes.

What these are

Heavy Rain: Rainfall totals unusual for the place and season that did not produce a flood.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Montana in 2011 Every state in 2011 This day in weather history Warnings in Montana, July 2011

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 331100.