An upper level ridge of high pressure over the region allowed for generally weak disturbances to rotate around the main area of high pressure. Disturbances mainly affected the mountains of Central and Southwest Montana.
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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 TFX wrote it up.
An upper level ridge of high pressure over the region allowed for generally weak disturbances to rotate around the main area of high pressure. Disturbances mainly affected the mountains of Central and Southwest Montana. Isolated thunderstorms developed in these regions mostly producing some lightning and brief heavy rainfall. A couple storms, mainly in and around the Helena Valley, became severe with strong wind gusts and large hail.
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 Great Falls, MT wrote its last area forecast discussion before the first event at Jul 2, 4:45 PM MST, 15 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 545 PM MDT Tue Jul 2 2013 .DISCUSSION... Tonight through Thursday...An upper level ridge of high pressure continues to reside over the region this evening. However...weak upper level disturbances continue to rotate around the main area of high pressure. These disturbances will mainly affect the western mountains and SW MT. A few isolated thunderstorm are possible in these regions as a result. Most storms will only produce some lightning and brief heavy rainfall...but a few strong wind gust or small hail is possible from the stronger storms. Temperatures should be just a touch cooler on Wednesday...but still rather hot in several areas. Expect the cooling trend to continue into the 4th...but the chances for isolated thunderstorms will continue...especially during the late afternoon hours over portions of Central and SW MT. Brusda Thursday night through Tuesday...A cold front will sweep east across the region Thursday night as an upper level trough, originating in the Eastern Pacific, moves into Western Canada. the northern Rockies and MT will remain on the southern fringes of the the broad trough in Western Canada through early next week as generally weak shortwaves and upper level jet impulses move across the region in a westerly flow aloft. Temperatures will cool back to seasonal averages Friday and remain close to average levels through the weekend. There will be at least a slight chance for afternoon and evening thunderstorms each day as the airmass will become somewhat unstable each afternoon with the passage of embedded upper level disturbances within the broad trough bringing periods of enhanced convective activity, through the timing and location of these features are still uncertain. Model differences grow early next week with the ECMWF model holding on to the broad trough over western Canada through Tuesday, while the GFS begins to rebuilds an upper level ridge across the NW US about a day earlier, resulting in temperatures warming back to above average levels. Hoenisch && .AVIATION... Updated 2345Z VFR will prevail for the next 24 hours. Isolated thunderstorms will move across Southwest Montana and will create VCTS conditions for KHLN along with possibly affecting KBZN. Winds will generally be light and variable at all terminals this afternoon. Some brief intrusions below VFR conditions or Gusty winds will be possible in the vicinity of any shower or thunderstorm. Suk && .PRELIMINARY POINT TEMPS/POPS... GTF 62 94 56 90 / 10 10 10 20 CTB 60 89 53 85 / 0 10 10 10 HLN 65 95 60 91 / 10 20 20 20 BZN 59 94 54 90 / 10 20 20 20 WEY 46 85 44 82 / 10 20 30 40 DLN 60 91 55 88 / 20 20 20 30 HVR 63 95 61 91 / 0 10 10 20 LWT 59 91 55 87 / 10 20 20 20 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && weather.gov/greatfalls
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 317 AM MDT TUE JUL 2 2013 MTZ008>015-044>055-031145- BEAVERHEAD-NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-HILL- CASCADE-CHOUTEAU-CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON- TOOLE-LIBERTY-EASTERN PONDERA-BLAINE- SOUTHERN ROCKY MOUNTAIN FRONT-EASTERN TETON-JUDITH BASIN-FERGUS- JEFFERSON-BROADWATER-MEAGHER-GALLATIN- 317 AM MDT TUE JUL 2 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GREAT FALLS MT 418 PM MDT TUE JUL 2 2013 MTZ014-022300- CENTRAL AND SOUTHERN LEWIS AND CLARK MT- 418 PM MDT TUE JUL 2 2013 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL LEWIS AND CLARK COUNTY UNTIL 500 PM MDT... AT 415 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 13 MILES WEST OF WOLF CREEK...OR 33 MILES SOUTHWEST OF CASCADE...MOVING SOUTHEAST AT 15 MPH. HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM. * LOCATIONS IMPACTED INCLUDE... WOLF CREEK AND HOLTER LAKE... IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. LAT...LON 4697 11188 4678 11211 4705 11250 4719 11233 TIME...MOT...LOC 2218Z 311DEG 12KT 4706 11232 NL
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
517 PM MDT TUE JUL 02 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0500 PM HAIL 8 SW WOLF CREEK 46.92N 112.19W
07/02/2013 E1.00 INCH LEWIS AND CLARK MT DEPT OF HIGHWAYS
&&
SUKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
548 PM MDT TUE JUL 02 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0536 PM HAIL 5 NNE EAST HELENA 46.65N 111.90W
07/02/2013 E1.00 INCH LEWIS AND CLARK MT TRAINED SPOTTER
&&
SUKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
554 PM MDT TUE JUL 02 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0554 PM HAIL EAST HELENA 46.59N 111.91W
07/02/2013 E0.70 INCH LEWIS AND CLARK MT TRAINED SPOTTER
&&
SUKSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GREAT FALLS MT 555 PM MDT TUE JUL 2 2013 MTZ014-052-053-030045- BROADWATER MT-CENTRAL AND SOUTHERN LEWIS AND CLARK MT-JEFFERSON MT- 555 PM MDT TUE JUL 2 2013 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN LEWIS AND CLARK... EXTREME NORTHEASTERN JEFFERSON AND NORTHWESTERN BROADWATER COUNTIES UNTIL 645 PM MDT... AT 553 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR MONTANA CITY...OR NEAR HELENA...MOVING SOUTHEAST AT 25 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS STORM. * LOCATIONS IMPACTED INCLUDE... RURAL NORTHEASTERN JEFFERSON COUNTY... RURAL NORTHWESTERN BROADWATER COUNTY... RURAL SOUTHEASTERN LEWIS AND CLARK COUNTY... LAT...LON 4669 11156 4652 11186 4687 11213 4697 11201 TIME...MOT...LOC 2355Z 322DEG 22KT 4653 11197 NL
The Great Falls radar (KTFX), 86 km away, was scanning. The volume nearest the first event began at 00:02 UTC.
3 hail. Local standard time, as filed.
Hail estimated at 1.00 inches was visible on the Sieben Flats webcam 8 mi SW of Wolf Creek, MT.
Hail measuring 1.75 inches was reported 9 mi NNE of Helena, MT.
Hail measuring 1.00 inches was reported by a trained spotter 5 mi NNE of Helena, MT.
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 2026-09-24. Each event’s entry at NCEI: 467554, 467556, 467560.