A strong late spring storm system tracked slowly across northern Wyoming and South Dakota bringing much needed precipitation to portions of northeast Montana. The precipitation began early in the morning as rain before changing to heavy wet snow in the afternoon across Valley, Garfield, McCone and Prairie counties.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 strong late spring storm system tracked slowly across northern Wyoming and South Dakota bringing much needed precipitation to portions of northeast Montana. The precipitation began early in the morning as rain before changing to heavy wet snow in the afternoon across Valley, Garfield, McCone and Prairie counties. Most locations in these counties measured snow ranging between two and four inches by late evening; although heavier amounts of eight to nine inches were recorded in areas with higher terrain.
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 1, 9:32 AM MST, 28 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GLASGOW MT 1032 AM MDT THU MAY 1 2008 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY... MANY REPORTS OF RAIN CHANGING OR MIXING WITH SNOW FROM TERRY TO GLASGOW WILL PROMPT AN UPDATE TO CHANGE WX TO RAIN/SNOW AND TO INCLUDE SNOW AMOUNTS. SNOW IS GENERALLY MELTING WHEN IT HITS THE GROUND BUT SOME ACCUMULATION IS POSSIBLE IF IT CONTINUES. SCT PREVIOUS UPDATE... STRONG SYSTEM IS DUMPING RAIN ON MOST OF THE CWA...WITH THE HEAVIEST RAIN IN THE SOUTHEASTERN ZONES...UP TO AN INCH SO FAR. ELSEWHERE RAIN TOTALS RANGE FROM AROUND A HALF INCH AT WOLF POINT TO AROUND A QUARTER OF AN INCH AT GLASGOW AIRPORT. GFS AND NAM ARE BOTH CONSISTENT WITH RAIN CONTINUING ALL DAY. NAM AND GFS BUFKITS HAVE STOOD FAST WITH PRECIPITATION TYPE AS RAIN TODAY. DID KEEP A RAIN/SNOW MIX OVER THE BIG SHEEP MOUNTAINS BUT DO NOT EXPECT HEADLINE SNOW TODAY. ADJUSTED POPS AND QPF TO BETTER FIT OBSERVATIONS AND UPDATED MODELS. AS SURFACE TROUGH SHIFTS AROUND EXPECT AFTERNOON WINDS TO PICK UP SO WILL KEEP LAKE WIND ADVISORY GOING WITH NO CHANGES. SCT PREVIOUS DISCUSSION... EARLY AM WATER VAPOR IMAGERY CAPTURED A LARGE DOUBLE BARREL LOW ACROSS THE NORTHERN ROCKIES WITH A HEALTHY PLUME OF MOISTURE EVIDENT ACROSS EASTERN WYOMING NORTH INTO THE PLAINS OF MONTANA. THE SURFACE ANALYSIS SHOWED AN INVERTED TROF RUNNING FROM FAITH/SD NORTHWEST TO SCOBEY. MUCH OF THE LIGHT RAIN HAS BEEN CONFINED JUST TO THE WEST OF THIS TROF ALONG THE 850MB-700MB THERMAL GRADIENT /LEFTOVER FROM WEDNESDAYS COLD FRONT/ AND AN AXIS OF IMPRESSIVE UPPER DIVERGENCE. THIS ACTIVITY IS EXPECTED TO EXPAND NORTHWEST THRU THE MORNING WHILE BRINGING A GOOD CHANCE OF WETTING RAIN TO MOST AREAS. BY THIS AFTERNOON...THE UPPER LOW STRUCTURE WILL REFOCUS ITS ENERGY TO OUR SOUTH WHILE DRIVING A DOMINANT LOW INTO THE CENTRAL PLAINS. INGREDIENTS-BASED METHOD DURING THIS TIME SHOWS A FAVORABLE OVERLAP OF 850-500MB CONVERGENT Q VECTORS AND 2D FRONTOGENESIS OVER THE CWA...SO NO PROBLEMS WITH LIFT. REGARDING PRECIP TYPE...VARIOUS FORECAST SOUNDINGS /INCLUDING THE BIG SHEEPS EAST INTO WIBAUX COUNTY/ ADVERTISE A 2-3K FT DEEP ABOVE FREEZING LAYER IN THE LOW LEVELS RESULTING IN ALL RAIN UNTIL LATE TONIGHT WHEN ENOUGH DRY AIR IS FED SOUTH TO AID IN A CHANGEOVER TO SNOW. UNFORTUNATELY THE BEST FORCING BEGINS DEPARTING BY THIS TIME...SO AT THIS TIME DO NOT EXPECT MUCH IN THE WAY OF ACCUMULATING SNOW OUTSIDE OF AN INCH OR SO ALONG THE I-94 CORRIDOR OVERNIGHT. FOR A LATE SEASON EVENT SUCH AS THIS...A CLIMATOLOGICAL EXAMINATION OF VARIOUS DATA SETS FROM LATE APRIL INTO EARLY MAY REVEALS LIMITED CONFIDENCE IN THE LATEST HPC WWD SNOW AMOUNTS VERIFYING. FEEL THAT STEADY RAINFALL MUCH OF THE DAY AND LACK OF COLDER AIR TONIGHT SHOULD AID IN KEEPING ANY ACCUMULATIONS ON THE LIGHT SIDE. ONLY HEADLINE ISSUED WAS A LAKE WIND ADVISORY FOR TODAY GIVEN LAKE WINDS ALREADY FLIRTING WITH CRITERIA. HEALTHY GRADIENT FLOW SHOULD MAINTAIN WINDS 20 MPH MUCH OF THE DAY. PRECIPITATION EXITS THE SOUTH EARLY FRIDAY AS ALBERTA HIGH PRESSURE SETTLES INTO THE CWA. BY SATURDAY THIS HIGH WILL PUSH OFF TO OUR SOUTHEAST ALLOWING A WELCOME WESTERLY SURFACE FLOW TO DEVELOP ALL THE WHILE BOOSTING HIGH TEMPS BACK TO NEAR NORMAL VALUES. MCZ .LONG TERM...SATURDAY NIGHT THROUGH THURSDAY... APPEARS THAT THE PATTERN ACROSS AT LEAST THE NORTHERN THIRD OF THE COUNTRY BECOMES MORE PROGRESSIVE THIS EXTENDED PERIOD WHILE CUT OFF LOWS KEEP THINGS A BIT MORE STAGNANT FARTHER SOUTH ACROSS THE SOUTHERN HALF TO THIRD OF THE NATION. LOOKS LIKE THE UPPER FLOW WILL BE CHARACTERIZED BY A LOT OF WEAK SHORTWAVE TROFS AND RIDGES MOVING THRU. THUS NO BIG SYSTEMS ARE EXPECTED WITH PERHAPS A FEW ROUNDS OF LIGHT SHOWERS POSSIBLE. WILL NOT MAKE ANY MAJOR CHANGES TO THE CURRENT PACKAGE AS THERE IS ENUF PHASE DISAGREEMENT AMONGST THE MODELS FOR ME TO NOT WANT TO TRY AND TIME THESE WEAK WAVES. MODEL PERFORMANCE OF LATE NOT INSPIRING ENUF CONFIDENCE EITHER. TEMPERATURES ARE EXPECTED TO BE AT LEAST SEASONAL WITH A FEW DAYS ABOVE AS WARMER AIR MOVES IN WITH THE RIDGES. WILL NOT JUMP ON ANYTHING FOR NEXT THURSDAY AT THIS POINT AS MODELS TYPICALLY BRING FEATURES IN A BIT FAST AT THAT POINT IN TIME...BUT IT APPEARS THAT SOMETIME LATE NEXT WEEK ANOTHER DEEPER LOW PRESSURE SYSTEM WILL MOVE THRU WHICH COULD BRING SOME RAIN. && .AVIATION... LARGE AREA OF RAIN EXPECTED TO REMAIN ACROSS NORTHEAST MONTANA TODAY WITH CONDITIONS BOUNCING BETWEEN MVFR AND IFR FOR THE MOST PART...WITH SOME LIFR CONDITIONS LIKELY FOR AT LEAST SOME SHORT PERIODS. SURFACE TROF EXTENDING FROM KGDV TO KGGW IS KEEPING WINDS SLIGHTLY WEAKER THAN SURROUNDING AREAS WITH SPEEDS IN THE TEENS EXPECTED THROUGH THE DAY. CONDITIONS EXPECTED TO IMPROVE GRADUALLY TONIGHT AS THE STORM SYSTEM SINKS FARTHER SOUTHEAST INTO THE PLAINS. SOME SNOW MAY MIX WITH RAIN THIS EVENING OR EARLY TONIGHT BEFORE ENDING AS COLDER BUT DRIER AIR MOVES IN. VFR CONDITIONS EXPECTED FRIDAY WITH LIGHTER WINDS. RAE && .GLASGOW WATCHES/WARNINGS/ADVISORIES... LAKE WIND ADVISORY UNTIL 6 PM MDT THIS AFTERNOON FOR FORT PECK LAKE. && WEATHER.GOV/GLASGOW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 406 AM MDT THU MAY 1 2008 MTZ017-022-023-020000- CENTRAL AND SOUTHERN VALLEY-GARFIELD-MCCONE- 406 AM MDT THU MAY 1 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...TODAY AND TONIGHT A LAKE WIND ADVISORY IS IN EFFECT FROM 6 AM UNTIL 6 PM TODAY FOR FORT PECK LAKE. NORTHWEST WINDS OF 15 TO 25 MPH WILL BECOME NORTH BY THIS AFTERNOON WITH OCCASIONAL GUSTS TO 35 MPH POSSIBLE. THESE WINDS WILL SUBSIDE TO AROUND 15 MPH THIS EVENING. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY NO HAZARDOUS WEATHER EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. MTZ025>027-020000- DAWSON-PRAIRIE-WIBAUX- 406 AM MDT THU MAY 1 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...TODAY AND TONIGHT A STRONG STORM SYSTEM WILL BRING WIDESPREAD RAIN TO THE AREA TODAY. TEMPERATURES ARE EXPECTED TO REMAIN WARM ENOUGH THROUGHOUT TODAY INTO EARLY THIS EVENING TO SUPPORT ALL RAIN...HOWEVER BY LATE THIS EVENING A CHANGEOVER TO SNOW WILL LIKELY OCCUR WITH HIGHER ELEVATIONS SEEING THIS TRANSITION FIRST. THE LATEST INDICATIONS ARE THAT SNOWFALL AMOUNTS WILL BE VERY LIGHT WITH UP TO AN INCH POSSIBLE OVERNIGHT. STAY TUNED TO NOAA WEATHER RADIO...LOCAL MEDIA OR THE INTERNET FOR FURTHER INFORMATION AS THIS STORM CONTINUES TO UNFOLD. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY NO HAZARDOUS WEATHER EXPECTED AT THIS TIME. .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 heavy snow. Local standard time, as filed.
A co-op observer measured nine inches of snow in the Larb Hills located four miles southwest of Hinsdale.
Total snowfall ranged between four and six inches 15 miles east of Crow Rock. The snow and cold temperatures resulted in the death of several newborn calves in the higher elevations of the Big Sheep Mountains.
A spotter six miles southeast of Sand Springs estimated eight inches of snow.
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: 93101, 105577, 93102.