A persistent upper level trough over the northern Rockies supported multiple rounds of moderate to heavy rainfall across portions of central and northeast Montana. The excess water caused the Musselshell River near Mosby to briefly rise one foot above flood stage on the morning of the 25th before returning below flood stage that afternoon.
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.
A persistent upper level trough over the northern Rockies supported multiple rounds of moderate to heavy rainfall across portions of central and northeast Montana. The excess water caused the Musselshell River near Mosby to briefly rise one foot above flood stage on the morning of the 25th before returning below flood stage that afternoon. Also, flooding in Zortman resulted in a few area dirt roads being washed out.
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 May 23, 2:26 PM MST, 3 hours 34 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 326 PM MDT FRI MAY 23 2008 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY... LARGE CLOSED UPPER LOW CONTINUING TO DOMINATE MOST OF THE WEST...CENTERED OVER NV...WHILE CLOSED UPPER HIGH IS OVER MB. THIS STRONGLY BLOCKING PATTERN VERY SLOW TO CHANGE. DRIER AIRMASS QUICKLY MOVED INTO MOST OF OUR AREA TODAY FROM THE SE...SEEN WELL ON WATER VAPOR CHANNEL SATELLITE CHANNEL. MODELS HANDLED THIS VERY POORLY TODAY AS THIS DRY AIR PROVED MUCH MORE PROMINENT THAN MODELS HAD SHOWN YESTERDAY. THIS DRYNESS SEEN ON 12Z KGGW SOUNDING. THIS ALSO CASTS DOUBT ON MODEL ABILITY TO HANDLE SHORTWAVES TONIGHT...ALTHOUGH THERE IS INCREASING SHOWER ACTIVITY SEEN OVER SE MT AND WY MOVING NW. WILL LOWER EVE POPS. TIGHT SURFACE GRADIENTS CONTINUE TONIGHT...ALTHOUGH THE PEAK 59 KT WIND AT 850 MB HAS MOVED NW. AS EXPECTED...WINDS REMAIN A LITTLE BELOW WARNING CRITERIA...GUSTS UP TO 50 MPH REPORTED IN CWA. MORE CONVINCING IS THE PERSISTENCE OF ALL MODELS FOR SEVERAL DAYS WITH BREAKING THE UPPER LOW INTO 2...ONE PART MOVING NE AND THEN RE-CLOSING OFF OVER E MT SAT. IT ALSO BECOMES VERTICALLY STACKED. PLENTIFUL MOISTURE AND UPPER SUPPORT FOR SIGNIFICANT RAINFALL. THIS SYSTEM WILL RESULT IN SIGNIFICANT IN MOST OF OUR AREA THAT HASNT HAD ANY...OR VERY MUCH YET FROM THIS SYSTEM...WHILE ALREADY SOAKED PHILLIPS AND PETROLEUM COUNTIES GET QUITE A BIT MORE. COOLER MOS TEMPS FOR SAT LOOK GOOD DUE TO PRECIP. MODEL FORECAST SOUNDINGS FOR THE MOST PART NOT LOOKING FAVORABLE FOR MUCH CONVECTION THAT WOULD PRODUCE TSTORMS. THINK PRECIP TO BE MORE STRATIFORM SAT/SAT NIGHT. FINALLY...WINDS WILL DROP OFF AS THE LOW CENTER MOVES THRU NE ME SAT EVE. WITH THE CLOSED LOW...PREFER THE IDEA OF LINGERING HIGHER POPS FOR BOTH SAT NIGHT AND SUN. UPPER LOW SHOWING DEFINITE SIGNS OF WEAKENING AND MOVING NE OUT OF THE AREA BY SUN. WOULD EXPECT A LITTLE DRYING ANYWAY AS A SURFACE HIGH FROM CANADA MOVES S SHIFTING WIND TO THE N SUN. SIMONSEN .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY... EXTENDED PERIOD BEGINS SUNDAY NIGHT WITH THE LARGE UPPER TROUGH OVER THE INTERMOUNTAIN WEST BECOMING AN OPEN WAVE WITH A CLOSED ANTICYCLONE SPINNING OVER THE PRAIRIE PROVINCES OF CANADA. AT THE SURFACE...A CANADIAN HIGH PRESSURE SYSTEM IS SINKING SOUTHWARD...WHICH CREATES A BAROCLINIC ZONE JUST SOUTH OF THE INTERNATIONAL BORDER. THIS WILL COMBINE WITH MID-LEVEL DEFORMATION TO CONTINUE THE RECENT UNSETTLED PATTERN WITH AREAS OF RAIN OVER THE CWA. 850MB TEMPERATURES AROUND 0C IN THE NORTH CENTRAL PART OF THE CWA COULD ALLOW FOR A FEW FLAKES OF SNOW TO MIX IN. FROM MONDAY THROUGH WEDNESDAY THE CANADIAN HIGH PRESSURE CONTINUES TO SINK SOUTH AND EAST...WHILE THE LONGWAVE UPPER TROUGH RETROGRADES WEST...ALLOWING FOR UPPER RIDGING TO DEVELOP OVER THE NORTHERN HIGH PLAINS. THIS WILL BRING A WARMING AND DRYING TREND TO THE CWA WITH TEMPERATURES RETURNING TO SEASONAL AVERAGES BY THE MIDDLE OF THE WEEK. UPPER ENERGY LARGELY STAYS SOUTH OF THE CWA DURING THIS PERIOD WITH ONLY THE FAR SOUTHERN ZONES GETTING CLIPPED BY A SHORTWAVE ON TUESDAY. UPPER FLOW BECOMES SOUTHWESTERLY BY LATE WEEK AS THE UPPER RIDGE AXIS MOVES EAST. AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS IS EXPECTED BY THIS PERIOD. HOWEVER...THERE ARE DIFFERENCES IN THE DETAILS BETWEEN THE OPERATIONAL GFS AND ECMWF...AS WELL AS SCATTER AMONG THE GFS ENSEMBLES. AJZ && .AVIATION... AN EAST WIND OF 20 TO 35KT WITH GUSTS TO 45KTS WILL CONTINUE FOR THE NEXT 24 HOURS. AREAS OF RAIN AND LOWER CEILINGS ARE MOVING NORTHWARD AND SOME AREAS ARE SEEING BREAKS IN CLOUDINESS. MORE PRECIPITATION WILL BE MOVING INTO THE AREA AFTER 03Z AND CONTINUE ON AND OFF THROUGH 18Z TOMORROW. MVFR CONDITIONS ARE POSSIBLE AT TIMES THROUGH THE FORECAST PERIOD. && .GLASGOW WATCHES/WARNINGS/ADVISORIES... LAKE WIND ADVISORY UNTIL 9 PM MDT SATURDAY FOR FORT PECK LAKE. FLASH FLOOD WATCH THROUGH SUNDAY MORNING FOR PETROLEUM. && WEATHER.GOV/GLASGOW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 311 PM MDT FRI MAY 23 2008 MTZ017-022-023-242115- CENTRAL AND SOUTHERN VALLEY-GARFIELD-MCCONE- 311 PM MDT FRI MAY 23 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT A LARGE LOW PRESSURE SYSTEM OVER THE WESTERN UNITED STATES WILL CONTINUE TO BRING STRONG EASTERLY WINDS TO EASTERN MONTANA. A LAKE WIND ADVISORY REMAINS IN EFFECT FOR FORT PECK LAKE THROUGH SATURDAY EVENING. EAST WINDS OF 25 TO 40 MPH ARE EXPECTED OVER THE AREA TONIGHT WITH WINDS EVENTUALLY DECREASING INTO THE 15 TO 25 MPH RANGE BY SATURDAY AFTERNOON. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THE LAKE WIND ADVISORY WILL CONTINUE THROUGH SATURDAY EVENING. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. MTZ021-242115- PETROLEUM- 311 PM MDT FRI MAY 23 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT A FLASH FLOOD WATCH IS IN EFFECT THROUGH SATURDAY MORNING FOR A POTENTIAL DAM FAILURE OF THE DUCK CREEK DAM IN WEST CENTRAL PETROLEUM COUNTY. ANOTHER HALF INCH TO INCH AND A HALF OF RAINFALL IS POSSIBLE IN PETROLEUM COUNTY WITH THE STORM SYSTEM THAT IS OVER THE WESTERN UNITED STATES. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THE FLASH FLOOD WATCH IS IN EFFECT FOR A POTENTIAL DAM FAILURE IN WEST CENTRAL PETROLEUM COUNTY. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
The national radar mosaic for the moment the first event began.
3 flood. Local standard time, as filed.
Flooding was observed on a few area dirt roads resulting in portions of the road surfaces washing out.
Flatwillow Creek was observed running over its banks five miles west of Petrolia Lake.
A trained spotter reported bank breaches on Box Elder and McDonald Creeks.
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, May 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: 105593, 100489, 100511.