Several witnesses reported a funnel cloud or cold-air funnel south of Bozeman on a cold, showery day.
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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.
Several witnesses reported a funnel cloud or cold-air funnel south of Bozeman on a cold, showery 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 Great Falls, MT wrote its last area forecast discussion before the first event at May 23, 7:49 AM MST, 2 hours 41 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 849 AM MDT WED MAY 23 2007 .UPDATE...UPDATE TO ZONES PLANNED BY 930...THE UPPER LEVEL LOW PRESSURE TROF HAS MOVED INTO WESTERN DAKOTAS. NORTHWEST FLOW ALOFT CONTINUES OVER THE ZONES AND THE AIRMASS WILL REMAIN UNSETTLED THROUGH THE DAY. VIRGA AND SHOWERS ARE ALREADY PRESENT IN THE MORNING SKY AND INSTABILITY WILL INCREASE DURING THE AFTERNOON...NORTHERN ROCKIES PLAINS NEAR CTB WILL SEE THE GREATEST INSTABILITY. UPDATED MAINLY TO FRESHEN FIRST PERIOD SKY COVER AND REDUCE THUNDERSTORM COVERAGE. ZELZER && .PREV DISCUSSION... (ISSUED 615 AM MDT WED MAY 23 2007) DISCUSSION... TODAY THROUGH FRIDAY...A QUIETER PATTERN TODAY AS THE AREA IS BETWEEN TWO SYSTEMS. THE UPPER LOW THAT BROUGHT THE LOW CLOUDS AND PRECIPITATION YESTERDAY IS NOW OVER SOUTHEAST MONTANA AND CONTINUES TO LIFT TO THE NORTHEAST. CIRCULATION ASSOCIATED WITH THIS FEATURE CONTINUES TO PROVIDE SOME LINGERING LIGHT SHOWERS TO THE EXTREME EASTERN PORTION OF THE COUNTY WARNING AREA BUT THESE SHOWERS WILL QUICKLY END THIS MORNING. THE HIGHLIGHTS CURRENTLY IN PLACE FOR SNOW WILL END WITH THE ISSUANCE OF THIS MORNINGS ZONES. A NORTHWEST FLOW ALOFT OVER THE AREA TODAY WITH LOW LEVEL MOISTURE AROUND. WITH THINNING CLOUDS AND AFTERNOON HEATING...EXPECT SHOWERS TO DEVELOP. WITH THE POCKET OF COLD AIR ALOFT OVER THE AREA ISOLATED THUNDERSTORMS WILL ALSO BE A POSSIBILITY. RATHER STRANGE PATTERN CONTINUES TO UNFOLD AS A CLOSED UPPER LOW DROPS SOUTH OUT OF WESTERN ALBERTA. MODELS DROP THIS FEATURE OVER SOUTHWEST MONTANA OVERNIGHT THURSDAY AND THEN MOVE IT ACROSS SOUTHERN MONTANA FRIDAY. THIS FEATURE WEAKENS AS IT PROGRESSES SOUTH BUT SHOULD GENERATE PRECIPITATION ACROSS THE AREA...ESPECIALLY THURSDAY NIGHT. MODELS DIFFER ON THE EXACT DETAILS BUT IT APPEARS THE AIRMASS WILL NOT BE SIGNIFICANTLY COLD TO SUPPORT HEAVY SNOWS. WILL NOT ISSUE ANY HIGHLIGHTS AT THIS TIME BUT WILL CONTINUE TO MONITOR THIS FEATURE AS IT APPROACHES THE AREA. TEMPERATURES WILL CONTINUE TO BE BELOW SEASONAL AVERAGES. EMANUEL FRIDAY NIGHT THROUGH SATURDAY NIGHT...THE UPPER LEVEL DISTURBANCE THAT MOVES THROUGH THE REGION ON THURSDAY WILL BE EXITING THE REGION ON FRIDAY NIGHT. THUS SHOWERS SHOULD COME TO AN END OVER MUCH OF THE REGION ON FRIDAY NIGHT. FOR SATURDAY...A WEAK UPPER LEVEL RIDGE WILL BUILD OVER THE REGION...ALLOWING FOR SLIGHTLY WARMER AIR TO MOVE INTO THE AREA...ALONG WITH MOSTLY DRY CONDITIONS. ON SUNDAY...A MILD SOUTHWESTERLY FLOW ALOFT WILL DEVELOP OVER THE REGION. TEMPERATURES WILL CONTINUE THE WARMING TREND...AND SHOULD BE A FEW DEGREES ABOVE NORMAL IN MOST LOCATIONS. HOWEVER...ANOTHER UPPER LEVEL DISTURBANCE IS EXPECTED TO MOVE INTO THE REGION BY LATE SUNDAY AFTERNOON...ALLOWING FOR SCATTERED THUNDERSTORMS TO DEVELOP. SUNDAY NIGHT AND MEMORIAL DAY...EXPECT A PERIOD OF RAIN AND THUNDERSTORMS TO MOVE ACROSS THE REGION SUNDAY NIGHT AND MEMORIAL DAY MORNING...WITH THE BEST CHANCE FOR PRECIP OCCURRING OVER CENTRAL MONTANA. THIS DISTURBANCE SHOULD BE QUICK MOVING...SO MOST OF THE PRECIP WILL EXIT CENTRAL MONTANA BY EARLY AFTERNOON. BECAUSE OF CLOUD COVER/PRECIP...TEMPERATURES WILL BE SLIGHTLY COOLER. BRUSDA TUESDAY AND WEDNESDAY...A HIGH PRESSURE RIDGE IS EXPECTED TO BUILD IN FROM THE WEST AS A LOW PRESSURE MOVES TO THE EAST. DUE TO TIMING ISSUES FOR THE TWO FEATURES KEPT A CHANCE FOR PRECIPITATION THROUGH THE PERIOD. TEMPERATURES WILL BE NEAR NORMAL. SAUCIER AVIATION... UPDATED 1215Z. A STRONG UPPER LEVEL LOW CONTINUES TO ROTATE OVER EASTERN MONTANA. AS A RESULT...SCATTERED LIGHT RAIN SHOWERS CONTINUE TO MOVE SOUTH THROUGH NORTH CENTRAL AND SOUTHWEST MONTANA. THIS WEATHER PATTERN WILL CONTINUE THROUGH 01Z THURSDAY...BEFORE THE AIRMASS STABILIZES AND THE SHOWERS DIMINISH. VFR/MVFR CONDITIONS CAN BE EXPECTED OVER THE REGION UNTIL 02Z...BEFORE CEILINGS LIFT A BIT AS SOME DRIER AIR MOVES INTO THE REGION. EXPECT INCREASING CLOUDS THOUGH AFTER 05Z THURSDAY OVER NORTH CENTRAL MONTANA...AS THE NEXT DISTURBANCE MOVES INTO THE REGION BY THURSDAY AFTERNOON...BRINGING WITH IT MORE WIDESPREAD IFR CONDITIONS FOR THURSDAY AFTERNOON AND NIGHT. BRUSDA && .PRELIMINARY POINT TEMPS/POPS... GTF 56 37 57 35 / 30 20 50 60 CTB 56 35 50 33 / 30 20 60 60 HLN 56 38 58 38 / 30 20 40 50 BZN 57 34 58 35 / 30 10 30 50 WEY 46 25 50 28 / 20 20 20 30 DLN 55 35 58 36 / 30 10 30 30 HVR 58 38 60 36 / 20 20 40 30 LWT 52 35 58 37 / 30 20 40 50 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 540 AM MDT WED MAY 23 2007 MTZ009-010-012-014-046-048-049-241145- NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-CASCADE- CENTRAL AND SOUTHERN LEWIS AND CLARK-EASTERN PONDERA- SOUTHERN ROCKY MOUNTAIN FRONT-EASTERN TETON- 540 AM MDT WED MAY 23 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT THERE IS A LOW PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY AN UPPER LEVEL WEATHER SYSTEM WILL MOVE SOUTH OUT OF CANADA THURSDAY NIGHT AND FRIDAY. HEAVY SNOW IS A POSSIBILITY OVER THE MOUNTAINS AND HIGHER TERRAIN. STAY TUNED FOR FURTHER UPDATES REGARDING THIS POTENTIAL STORM. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. MTZ008-011-013-015-044-045-047-050>055-241145- BEAVERHEAD-HILL-CHOUTEAU-MADISON-TOOLE-LIBERTY-BLAINE- JUDITH BASIN-FERGUS-JEFFERSON-BROADWATER-MEAGHER-GALLATIN- 540 AM MDT WED MAY 23 2007 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...THURSDAY THROUGH TUESDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
844 AM MDT WED MAY 23 2007
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0820 AM HEAVY SNOW 3 E HALF MOON PASS 46.77N 109.28W
05/23/2007 E13.0 INCH FERGUS MT TRAINED SPOTTER
STORM TOTAL SINCE AFTERNOON OF 5/21...WITH 2.7 INCHES
LIQUID WATER EQUIVALENT
&&
DZUMPFEThe Billings radar (KBLX), 187 km away, was scanning. The volume nearest the first event began at 17:25 UTC.
1 funnel cloud. Local standard time, as filed.
Several witnesses reported and took photos of a funnel cloud on a cold-air funnel type of day (showery, convective, cool). No damage a funnel did not touch down.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2007Every state in 2007This day in weather historyWarnings in Montana, May 2007
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: 24276.