Among some benign surface features, a modearately moist and warm atmosphere was able to set off a number of severe thunderstorms.
Every event with a place to put it. Tap one for its entry below.
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.
The episode as NWS GGW wrote it up.
Among some benign surface features, a modearately moist and warm atmosphere was able to set off a number of severe thunderstorms.
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 Glasgow, MT wrote its last area forecast discussion before the first event at Jul 20, 3:22 PM MST, 1 hour 13 minutes earlier.
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</html>HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 449 PM MDT SAT JUL 20 2013 MTZ016>027-059>062-211100- CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY- DANIELS-SHERIDAN-WESTERN ROOSEVELT-PETROLEUM-GARFIELD-MCCONE- RICHLAND-DAWSON-PRAIRIE-WIBAUX-NORTHERN PHILLIPS- SOUTHWEST PHILLIPS-NORTHERN VALLEY-EASTERN ROOSEVELT- 449 PM MDT SAT JUL 20 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND TONIGHT... MOSTLY NEAR THE CANADIAN AND NORTH DAKOTA BORDERS. STRONGER STORMS WILL LIKELY HAVE SOME BRIEF HEAVY RAIN...SMALL HAIL...GUSTY WINDS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY A COLD FRONT MOVING THROUGH THE REGION ON SUNDAY WILL GENERATE GUSTY NORTHWEST WIND. THEREFORE A LAKE WIND ADVISORY IS IN EFFECT FOR FORT PECK LAKE FROM NOON UNTIL 9 PM SUNDAY. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
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</html>The Glasgow radar (KGGW), 56 km away, was scanning. The volume nearest the first event began at 23:36 UTC.
11 hail, 3 thunderstorm wind. Local standard time, as filed.
Trained spotter reported hail up to the size of nickels. Location on the edge of the storm.
Trained spotter reported quarter-sized hail.
Public reported hail up to the size of golf balls.
Trained spotter reported hail up to the size of quarters, winds up to 30 mph, and moderate rain reducing visibility to one-half mile.
A wind gust of 67 mph was recorded at the Cow Creek DOT site.
Public reported that some metal fencing was damaged.
Public reported a 78 mph wind gust.
Trained spotter reported hail up to the size of baseballs and heavy rain.
Cooperative observer reported hail up to the size of golf balls and heavy rain.
Trained spotter reported hail up to the size of golf balls.
Public reported quarter-sized hail.
Public reported hail up to the size of half dollars.
Trained spotter reported hail up to the size of golf balls.
Cooperative observer reported hail up to the size of golf balls.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2013Every state in 2013This day in weather historyWarnings in Montana, July 2013
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 2026-10-01. Each event’s entry at NCEI: 471441, 471443, 471445, 471449, 471454, 471452, 471456, 471450, 471457, 471458, 471460, 471461, 471462, 471463.