Afternoon thunderstorms developed over Judith Basin producing strong winds and small hail.
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 TFX wrote it up.
Afternoon thunderstorms developed over Judith Basin producing strong winds and small 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 May 29, 10:22 AM MST, 2 hours 57 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 1122 AM MDT TUE MAY 29 2012 UPDATED AVIATION SECTION .UPDATE... CURRENT FORECAST LOOKS GENERALLY ON TRACK. IT STILL LOOKS LIKE AN UPPER TROUGH WILL MOVE INTO NORTHWEST MONTANA THIS AFTERNOON. AHEAD OF THIS UPPER TROUGH AN AREA OF LIFT WILL SPREAD EAST ACROSS THE AREA THIS AFTERNOON. WITH AN UNSTABLE AIRMASS IN PLACE EXPECT AN AREA OF SHOWERS AND THUNDERSTORMS TO SPREAD EAST IN LINE WITH THE LIFT. AS FOR CHANGES TO THE FORECAST BASED ON EXPECTED TIMING OF THE SHOWERS AND THUNDERSTORMS DROPPED THE MENTION OF SAME OVER TOOLE AND LIBERTY COUNTIES FOR THE REST OF THIS MORNING. ADDED THE THREAT OF GUSTY WINDS WITH THE THUNDERSTORMS THIS AFTERNOON. WENT WITH MORE OF A PARTLY CLOUDY SKY OVER EASTERN PORTIONS OF SOUTHWEST MONTANA THIS MORNING. RAISED HIGH TEMPERATURES IN PORTIONS OF THE EAST FOR TODAY A FEW DEGREES. && .AVIATION... UPDATED 1722Z. A SHORTWAVE WILL MOVE THROUGH WEST FLOW ALOFT AND CROSS THE ROCKIES THIS AFTERNOON AND EVENING. THE AIRMASS WILL BECOME UNSTABLE WITH SCATTERED TO NUMEROUS THUNDERSTORMS ACROSS THE REGION. GUSTY WINDS 35 TO 45 KTS AND SMALL HAIL ARE EXPECTED WITH THESE THUNDERSTORMS. AN ASSOCIATED COLD FRONT WILL MOVE THROUGH THE REGION THIS AFTERNOON AND EARLY EVENING. GUSTY WINDS AND ENHANCED THUNDERSTORM ACTIVITY ARE EXPECTED WITH COLD FRONT PASSAGE. MVFR CONDS ARE POSSIBLE NEAR THUNDERSTORMS...ELSEWHERE VFR CONDS WILL PREVAIL THROUGH THE NEXT 24 HOURS. && .HYDROLOGY... THE FLOOD WARNING CONTINUES FOR CLEAR CREEK IN BLAINE COUNTY UNTIL FURTHER NOTICE. CLEAR CREEK AT THE GAUGE LOCATION IS HOVERING AROUND FLOOD STAGE...WITH THE CURRENT FORECAST FROM THE MISSOURI BASIN RIVER FORECAST CENTER KEEPING THE CREEK NEAR FLOOD STAGE INTO TUESDAY MORNING. WITH RUNOFF AND MELTING SNOW CONTINUING IN THE BEARS PAW MOUNTAINS...THE FLOOD WARNING WILL CONTINUE UNTIL THE THREAT FOR FLOODING HAS DIMINISHED. && .PREV DISCUSSION... /ISSUED 605 AM MDT TUE MAY 29 2012/ TODAY THROUGH THURSDAY...A TRANSIENT HIGH PRESSURE RIDGE OVER MONTANA WILL CONTINUE TO MOVE EAST THROUGH THE MORNING AHEAD OF AN INCOMING SHORTWAVE. MOISTURE COMBINED WITH INSTABILITY WILL LIKELY LEAD TO ROUND OF SHOWERS AND SCATTERED THUNDERSTORMS MOVING FROM WEST TO EAST THROUGH THE EARLY EVENING. SHEAR...MOISTURE...AND INSTABILITY VALUES INDICATE A POTENTIAL FOR SOME SMALL HAIL TO FALL FROM SOME MATURE CELLS. THE SHORTWAVE LOOKS TO MOVE THROUGH THE REGION FAIRLY QUICKLY HOWEVER...EXITING TO THE EAST LATER THIS EVENING. WINDS WILL BECOME BREEZY AND SHIFT MORE WESTERLY TONIGHT BEHIND THE SHORTWAVE. WEST TO NORTHWEST FLOW TAKES OVER WEDNESDAY AND SOME LINGERING MOISTURE AND INSTABILITY WILL KEEP A THREAT FOR SHOWERS OVER NORTH-CENTRAL MONTANA. EXPECT HIGHER PRESSURE TO KEEP THE SOUTHERN PORTIONS OF CENTRAL MONTANA ONLY PARTLY CLOUDY WEDNESDAY. CLOUDS WILL INCREASE FROM THE WEST THROUGH THE DAY THURSDAY AHEAD OF YET ANOTHER INCOMING LOW PRESSURE SYSTEM. TEMPERATURES LOOK TO STEADILY WARM THE NEXT FEW DAYS...WITH HIGHS REACHING THE LOW 70S BY THURSDAY. THURSDAY NIGHT THROUGH TUESDAY...A HIGH WEAK PRESSURE RIDGE WILL BE OVER THE REGION THURSDAY NIGHT BUT SEVERAL DISTURBANCES WILL BE MOVING THROUGH THE FLOW ALOFT AND KEEPING THE AIRMASS UNSETTLED. A BROAD LOW PRESSURE TROF OVER THE EASTERN PACIFIC WILL APPROACH THE WEST COAST FRIDAY NIGHT AND FLOW ALOFT WILL SWITCH TO THE SOUTHWEST OVER THE ZONES. MOISTURE WILL INCREASE ACROSS THE REGION AND PASSAGE OF A SHORTWAVE SATURDAY WILL INCREASE THE CHANCE OF SHOWERS AND THUNDERSTORMS. THIS SHORTWAVE WILL ALSO TIGHTEN THE SURFACE PRESSURE GRADIENT ACROSS THE REGION. STRONG AND GUSTY WINDS WILL DEVELOP BY SATURDAY AND CONTINUE INTO SUNDAY. WEAK HIGH PRESSURE WILL BUILD ALOFT SUNDAY NIGHT AND THE AIRMASS WILL WARM AND DRY THROUGH MONDAY. THE NEXT LOW PRESSURE SYSTEM WILL MOVE THE WEST COAST MONDAY NIGHT AND THE ASSOCIATED COLD FRONT WILL BRING COOLER TEMPS TUESDAY. TEMPS WILL BEGIN THE PERIOD ABOVE SEASONAL NORMALS BUT COOL LATE SUNDAY THROUGH TUESDAY TO BELOW NORMALS. ZELZER && .PRELIMINARY POINT TEMPS/POPS... GTF 65 40 67 44 / 70 30 0 10 CTB 58 39 65 42 / 70 20 10 10 HLN 67 40 67 43 / 60 10 10 10 BZN 68 38 65 39 / 50 40 10 10 WEY 57 33 57 33 / 30 40 10 10 DLN 66 39 64 39 / 20 20 10 10 HVR 66 41 67 44 / 60 70 10 10 LWT 61 39 62 40 / 60 70 10 10 && .TFX WATCHES/WARNINGS/ADVISORIES... FLOOD WARNING FOR CLEAR CREEK IN BLAINE COUNTY NEAR THE TOWN OF CHINOOK UNTIL FURTHER NOTICE. && SHORT TERM...BLANK LONG TERM...MLS AVIATION...MLS WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 345 AM MDT TUE MAY 29 2012 MTZ047-300945- BLAINE- 345 AM MDT TUE MAY 29 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL MONTANA. .DAY ONE...TODAY AND TONIGHT A FLOOD WARNING REMAINS IN EFFECT FOR PORTIONS OF CLEAR CREEK IN BLAINE COUNTY. A ROUND OF SHOWERS AND THUNDERSTORMS...POSSIBLY PRODUCING SMALL HAIL...WILL TREK ACROSS THE REGION FROM THE WEST THIS AFTERNOON. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY A FLOOD WARNING REMAINS IN EFFECT FOR PORTIONS OF CLEAR CREEK IN BLAINE COUNTY UNTIL FURTHER NOTICE. .SPOTTER INFORMATION STATEMENT... ANY REPORTS OF FLOODING WOULD BE GREATLY APPRECIATED. MTZ008>015-044>046-048>055-300945- BEAVERHEAD-NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-HILL- CASCADE-CHOUTEAU-CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON- TOOLE-LIBERTY-EASTERN PONDERA-SOUTHERN ROCKY MOUNTAIN FRONT- EASTERN TETON-JUDITH BASIN-FERGUS-JEFFERSON-BROADWATER-MEAGHER- GALLATIN- 345 AM MDT TUE MAY 29 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT A ROUND OF SHOWERS AND THUNDERSTORMS...POSSIBLY PRODUCING SMALL HAIL...WILL TREK ACROSS THE REGION FROM THE WEST THIS AFTERNOON. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... ANY REPORTS OF HAIL WOULD BE GREATLY APPRECIATED.
The Great Falls radar (KTFX), 71 km away, was scanning. The volume nearest the first event began at 20:18 UTC.
1 thunderstorm wind. Local standard time, as filed.
Thunderstorms produced a wind gust to 51KT (59 mph) at the Geyser DOT sensor.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2012Every state in 2012This day in weather historyWarnings in Montana, May 2012
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: 385737.