A very unstable airmass covering most of North central Montana allowed widespread severe weather to develop. Numerous severe thunderstorms were reported.
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.
A very unstable airmass covering most of North central Montana allowed widespread severe weather to develop. Numerous severe thunderstorms were reported. Hail the size of golf balls and wind gusts in excess of 70 mph were common.
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 4, 2:14 PM MST, 46 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 314 PM MDT FRI JUL 4 2008 .DISCUSSION... ...SEVERE THUNDERSTORM WATCH ISSUED FOR SOUTHWEST AND CENTRAL MONTANA IN EFFECT UNTIL 10 PM MDT... ...SEVERE WEATHER LIKELY THIS AFTERNOON AND EVENING OVER THE ENTIRE AREA... STRONG INSTABILITY IS FORECAST TO DEVELOP THIS AFTERNOON OVER THE ENTIRE FORECAST AREA...AS A VIGOROUS UPPER LEVEL SHORTWAVE TROUGH AND ASSOCIATED JET STREAK AFFECT THE REGION. LATEST 12Z OPERATIONAL FORECAST MODELS SHOW A 55KT TO 60KT JET STREAK ARRIVING OVER NORTHWEST MONTANA THIS EVENING...WITH SURFACE BASED CAPES EXCEEDING 2500 J/KG. AN UPPER LEVEL VORT MAX OVER WESTERN WASHINGTON IS EXTRAPOLATED TO BE JUXTAPOSED WITH THIS JET STREAK BY 6PM. MODELS HAVE INDICATED A STRENGTHENING TREND WITH THIS JET STREAK...WITH EARLIER RUNS 10 KTS OR SO LESS. ALSO...LATEST RUNS SHOW A FURTHER NORTHWARD JET PLACEMENT...SUGGESTING THAT THE FORECAST AREA WILL HAVE A GREAT CHANCE OF EXPERIENCING FAVORABLE ASCENT IN THE RIGHT ENTRANCE REGION OF THE JET THIS EVENING. SEVERAL COMPLICATING FACTORS HAVE BEEN NOTED IN THE LOW LEVELS. FOR EXAMPLE...LOW LEVEL MOISTURE POOLING NORTH OF A DEVELOPING SURFACE CYCLONE OVER CENTRAL MONTANA HAS BEEN A BIT STRONGER THAN ANTICIPATED. CLOUD COVERAGE THIS MORNING OVER THE NORTHERN HALF OF THE FORECAST AREA MAY LIMIT DEEPER MIXING...THUS MAINTAINING HIGHER LOW LEVEL MOISTURE AND INSTABILITY THROUGH THE DAY. DEWPOINTS IN THE LOWER 60S HAVE ALREADY BEEN NOTED ON EITHER SIDE OF THE DIVIDE...RESULTING IN RUC-ANALYSIS SURFACE-BASED CAPES FROM 1500-2000 J/KG ALREADY AT 11 AM MDT...WITH MIXED LAYER CAPES ABOUT 500 J/KG LOWER. HOWEVER...THERE STILL REMAINS A CAP IN THE LOWER ATMOSPHERE THIS MORNING...WITH CONVECTIVE INHIBITION OVER 100 J/KG ACROSS THE FORECAST AREA. WITH TIME...SUFFICIENT COLD AIR ADVECTION ALOFT IN ASSOCIATION WITH HEIGHT FALLS WITH THE APPROACHING UPSTREAM TROUGH WILL HELP TO ERODE THE CAP...WITH CONVECTIVE INITIATION EXPECTED OVER THE HIGHER TERRAIN BY 2 PM MDT OR SO. INTERESTINGLY...A LEAD SHORTWAVE TROUGH WAS SUFFICIENT FOR HIGHER-BASED STORMS OVER NORTHWEST MONTANA THAT TRACKED INTO ALBERTA. AN OUTFLOW BOUNDARY IS SURGING SOUTHWARD...SHIFTING WINDS TO NORTHEASTERLY IMMEDIATELY BEHIND IT. THIS BOUNDARY IS FORECAST TO BECOME DIFFUSE THIS AFTERNOON...AS IT TRACKS AWAY FROM ITS PARENT CONVECTION. HOWEVER...REMAINING LOW LEVEL VORTICITY WITH THIS BOUNDARY MAY BECOME A KEY PLAYER IN CONVECTIVE ENHANCEMENTS THIS AFTERNOON. AS IT CURRENTLY STANDS...MODELS ARE ALL OVER THE PLACE WITH REGARD TO CONVECTIVE COVERAGE. THE RUC AND NAM SHOW A FASTER NORTH-SOUTH BOUNDARY PASSAGE...BRINGING WESTERLY WINDS ACROSS MUCH OF THE REGION BY MID-AFTERNOON...AND WITH THE GFS SHOWING A MUCH SLOWER PASSAGE. WITH THE UPSTREAM ASCENT BEING RATHER WEAK AT FIRST...WE ONLY EXPECT ISOLATED STORMS TO DEVELOP THIS AFTERNOON...WITH MORE WIDESPREAD COVERAGE AFTER 600 PM...ESPECIALLY OVER NORTH CENTRAL MONTANA. COVERAGE COULD BE MORE SPOTTY OVER SOUTHWEST MONTANA...THOUGH LATEST RUC SHOWS WIDESPREAD COVERAGE THERE AS WELL. OVERALL CONVECTIVE MORPHOLOGY IS ALSO VERY TRICKY...AS SOLUTIONS FAVORING THE WESTERLY LOW-LEVEL FLOW WOULD SUPPORT MORE UNIDIRECTIONAL WIND PROFILES AND A SQUALL LINE THREAT WITH THE DEEP-LAYER SHEAR VECTOR ORIENTED PARALLEL TO THE LOW LEVEL BOUNDARY. STRENGTHENING SOUTHWESTERLY 700 MB FLOW OVER 30KTS MAY ENHANCE DESCENDING REAR INFLOW JETS WITH ANY SQUALL LINES AS WELL AS THE DAMAGING WIND POTENTIAL. ON THE OTHER HAND...FAR EASTERN PORTIONS OF CENTRAL MONTANA WILL LIKELY EXPERIENCE LOW LEVEL FLOW BACKED TO THE SOUTHEAST FOR A LONGER PERIOD OF TIME...AND THUS A GREATER CHANCE FOR ROTATING UPDRAFTS. HOWEVER...AS TOTAL SHEAR MAGNITUDE WITHIN THE INSTABILITY LAYER INCREASES TO OVER 50 KTS THIS EVENING...EMBEDDED MESOCYCLONES AND VORTICES WITHIN SQUALL LINES WILL BECOME POSSIBLE...ESPECIALLY AS STRONGER PACIFIC MOISTURE AND ASSOCIATED INSTABILITY POOL INTO THE REGION WEST OF THE DIVIDE. ONLY WEAK LOW LEVEL WESTERLY FLOW WILL INHIBIT ANY SUBSTANTIAL DOWNSLOPE DRYING. ESSENTIALLY...ALL MODES OF CONVECTION WILL BE POSSIBLE THROUGH EVENING...WITH LARGE HAIL...DAMAGING WINDS...AND ISOLATED TORNADOES ALL POSSIBLE. A SPECIAL 18Z SOUNDING HAS BEEN RELEASED TO COLLECT ADDITIONAL ENVIRONMENTAL DATA. ACOHEN SATURDAY...TEMPERATURES WILL BE COOLER BUT STILL SLIGHTLY ABOVE SEASONAL NORMALS. SOME INSTABILITY OVER THE MOUNTAINS OF SOUTHWEST MONTANA MAY RESULT IN ISOLATED AFTERNOON THUNDERSTORMS. BRITTON SATURDAY NIGHT THROUGH SUNDAY...CONTINUE TO SEE SERIES OF WEATHER SYSTEMS WORK THROUGH REGION KEEPING RIDGE FLAT. ENOUGH INSTABILITY TO CREATE SOME SHOWERS AND THUNDERSTORMS...MAINLY SOUTHWEST WITH TEMPERATURES SEASONABLY WARM. LOSS && .AVIATION... UPDATED 1740Z. A LOW PRESSURE TROUGH WILL MOVE INTO ROCKIES THIS AFTERNOON. A COLDFRONT ASSOCIATED WITH THIS TROUGH WILL CROSS THE ROCKIES LATE THIS AFTERNOON AND MOVE INTO CENTRAL MONTANA LATER IN THE EVENING. SCATTERED THUNDERSTORMS ARE EXPECTED WITH FRONTAL PASSAGE. THE MAIN THREAT WILL BE STRONG...GUSTY WINDS AND LIGHTNING ASSOCIATED WITH THE THUNDERSTORMS. SMALL HAIL IS ALSO EXPECTED...AND SOME HAIL GREATER THAN ONE HALF INCH IS POSSIBLE. MVFR CONDITIONS SHOULD BE EXPECTED NEAR THUNDERSTORMS...ELSEWHERE VFR CONDITIONS WILL PREVAIL DURING THE NEXT 24 HOURS. BRITTON && .FIRE WEATHER... UPDATED 314 PM MDT. SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS SOUTHWEST...CENTRAL...AND NORTH CENTRAL MONTANA THIS AFTERNOON AND CONTINUE INTO THIS EVENING. TEMPERATURES THIS AFTERNOON ARE GENERALLY IN THE UPPER 80S TO MID 90S WITH DEWPOINTS IN THE UPPER 30S TO MID 50S. LOWER LEVELS OF THE ATMOSPHERE REMAIN RATHER DRY. THE MAIN THREAT FROM THESE STORMS WILL BE STRONG GUSTY WINDS AND OCCASIONAL DRY LIGHTNING. ALSO...BOTH THE OBSERVED FIRE DANGER CLASS FOR YESTERDAY AND THE FORECAST FIRE DANGER FOR TODAY ARE IN THE MODERATE RANGE. WILL THEREFORE ADDRESS THE POTENTIAL FOR DRY THUNDERSTORMS WITH A HEADLINE IN THE FIRE WEATHER PLANNING FORECAST. OVERNIGHT EXPECT COOL TEMPERATURES AND GOOD RELATIVE HUMIDITY RECOVERIES. SATURDAY AND SUNDAY TEMPERATURES WILL BE SOMEWHAT COOLER WITH SLIGHTLY LOWER RELATIVE DAYTIME HUMIDITIES...BUT GOOD OVERNIGHT RECOVERIES. BRITTON && .PRELIMINARY POINT TEMPS/POPS... GTF 55 81 54 82 / 50 20 20 20 CTB 50 78 51 79 / 40 10 10 10 HLN 58 83 56 85 / 50 20 20 20 BZN 52 79 52 84 / 40 30 30 20 WEY 46 72 45 77 / 30 30 30 30 DLN 49 78 49 79 / 50 30 20 20 HVR 55 85 55 84 / 40 10 10 10 LWT 51 76 52 82 / 40 20 20 20 && .TFX WATCHES/WARNINGS/ADVISORIES... SEVERE THUNDERSTORM WATCH NUMBER 656 IN EFFECT 2 PM MDT UNTIL 10 PM MDT. SEVERE THUNDERSTORM WATCH NUMBER 657 IN EFFECT 3 PM MDT UNTIL 10 PM MDT. && SHORT TERM...COHEN LONG TERM...LOSS AVIATION...BRITTON WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE GREAT FALLS MT 320 PM MDT FRI JUL 4 2008 MTZ008>015-044>055-051230- 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- 320 PM MDT FRI JUL 4 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR THE ENTIRE AREA UNTIL 1000 PM MDT THIS EVENING. SCATTERED SEVERE THUNDERSTORMS ARE LIKELY THIS AFTERNOON AND TONIGHT OVER THE WATCH AREA. DAMAGING WINDS...LARGE HAIL...AND HEAVY RAIN WILL BE POSSIBLE. AN ISOLATED TORNADO MAY ALSO BE POSSIBLE OVER CENTRAL AND NORTH CENTRAL MONTANA. LIGHTNING IS ALWAYS A CONCERN WITH ANY THUNDERSTORM. THOSE PLANNING OUTDOOR HOLIDAY ACTIVITIES TODAY AND TONIGHT ARE ENCOURAGED TO FREQUENTLY CHECK THE LATEST FORECASTS... WATCHES...AND WARNINGS FROM THE NATIONAL WEATHER SERVICE. THOSE OUTDOORS SHOULD MONITOR THE SKY FOR DEVELOPING STORMS AND HEAD FOR SHELTER AT THE FIRST INDICATION OF A THUNDERSTORM. ALSO...WITH THE RECENT RAINFALL AND WARM TEMPERATURES...ELEVATED WATER LEVELS MAY OCCUR ON AREA RIVERS...CREEKS...AND STREAMS. USE EXTRA CAUTION WHEN VENTURING OUT ON THE WATER THROUGH THIS WEEKEND. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS FOR SATURDAY THROUGH THURSDAY WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION HAS BEEN REQUESTED. WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. ACOHEN
The national radar mosaic for the moment the first event began.
27 thunderstorm wind, 16 hail. Local standard time, as filed.
A severe thunderstorm produced a wind gust to 83 mph at Townsend 8W.
A severe thunderstorm produced a wind gust to 60 mph at Valier 5W.
A severe thunderstorm dropped 1 inch diameter hail at Lennep 4NNW.
A severe thunderstorm dropped .88 inch diameter hail at Marysville 4WSW.
A severe thunderstorm produced a wind gust to 60 mph at Denton 9N. Many tree branches were reported downed.
A severe thunderstorm dropped 1.75 inch diameter hail at Pendroy.
A severe thunderstorm produced a wind gust to 65 mph at Hobson 4S.
A severe thunderstorm dropped .75 inch diameter hail at East Glacier Park 2N.
A severe thunderstorm dropped 1.25 inch diameter hail at Eden 16S.
A severe thunderstorm dropped .75 inch diameter hail at Marysville 8W.
A severe thunderstorm produced a wind gust to 60 mph at Lewistown 10SE.
A severe thunderstorm produced a wind gust to 60 mph at Moccasin 5NNE.
A severe thunderstorm produced a wind gust to 70 mph at Forest Grove 6NNE. Tree limbs 4 to 6 inches in diameter were broken.
A severe thunderstorm dropped .75 inch diameter hail at Lincoln 12E.
A severe thunderstorm produced a wind gust to 60 mph at Shelby 1W.
A severe thunderstorm dropped .75 inch diameter hail at Shelby 1W.
A severe thunderstorm produced a wind gust to 60 mph at Belt 1W. Numerous tree branches were reported downed and power was out for an hour.
A severe thunderstorm dropped 1.75 inch diameter hail at Choteau 4S.
A severe thunderstorm produced a wind gust to 60 mph at Great Falls 2S.
A severe thunderstorm dropped 1.75 inch diameter hail at Raynesford 11S.
A severe thunderstorm produced a wind gust to 60 mph at Canyon Creek 8S.
A severe thunderstorm produced a wind gust to 60 mph at Vaughn 3SE (Sun Prairie).
A severe thunderstorm produced a wind gust to 60 mph at Hilger 1W.
A severe thunderstorm dropped 1.75 inch diameter hail at Augusta 18SE (Bowmans Corners).
A severe thunderstorm produced a wind gust to 60 mph at Augusta 18SE (Bowmans Corners).
A severe thunderstorm produced a wind gust to 60 mph at Great Falls 12S.
A severe thunderstorm dropped .75 inch diameter hail at Pendroy 7WSW.
A severe thunderstorm dropped 1.75 inch diameter hail at Pendroy 7WSW.
A severe thunderstorm produced a wind gust to 60 mph at Choteau.
A severe thunderstorm dropped .75 inch diameter hail at Choteau.
A severe thunderstorm dropped .88 inch diameter hail at Geraldine.
A severe thunderstorm produced a wind gust to 60 mph at Shelby.
A severe thunderstorm dropped .88 inch diameter hail at Pendroy 13SW. Damage to a vegetable garden was reported.
A severe thunderstorm produced a wind gust to 70 mph at Big Sandy.
A severe thunderstorm produced a wind gust to 70 mph at Inverness 16S.
A severe thunderstorm produced a wind gust to 80 mph at Havre 21W. The wind knocked a railroad boxcar off the tracks spilling its content of Oreo cookies.
A severe thunderstorm produced a wind gust to 67 mph at the Havre ASOS site.
A severe thunderstorm produced a wind gust to 60 mph at Inverness 5S.
A severe thunderstorm produced a wind gust to 72 mph at Chinook 11S.
A severe thunderstorm produced a wind gust to 60 mph at the Havre ASOS site.
A severe thunderstorm produced a wind gust to 75 mph at Simpson 20E (Creedman Reservoir).
A severe thunderstorm produced a wind gust to 70 mph at Hogeland 7W. A 75 year-old tree was reported downed by the winds.
A severe thunderstorm produced a wind gust to 59 mph at Fort Belknap.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2008Every state in 2008This day in weather historyWarnings in Montana, July 2008
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: 123210, 123120, 123437, 123123, 123121, 123124, 123122, 123125, 123126, 123127, 123129, 123131, 123130, 123128, 123132, 123133, 123135, 123139, 123134, 123138, 123144, 123142, 123137, 123140, 123141, 123208, 123136, 123145, 123163, 123164, 123148, 123166, 123169, 123184, 123185, 123188, 123191, 123193, 123195, 123204, and more.