Winter Storm in Montana, May 18, 2003

Name: Winter Storm in Montana, May 18, 2003
Start: 2003-05-18T00:00
End: 2003-05-18T18:00
Location: Montana

May 18, 2003 · NWS TFX · 5 events in 5 counties and zones

A late season winter storm moved southeast, across much of North Central Montana on the 18th. Snow began to fall during the early morning hours on the 18th, and it ended by mid evening.

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 5

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.

What happened

The episode as NWS TFX wrote it up.

A late season winter storm moved southeast, across much of North Central Montana on the 18th. Snow began to fall during the early morning hours on the 18th, and it ended by mid evening. Snow accumulations occurred over all of the Plains, but was heaviest in the mountains.Here is a list of some of the snowfalls reported:8 inches at Benchland; 7 inches in Neihart 8N, Carter 27NW, Lewistown 22S, and Utica 20SW; 6 inches at Moore, 5 inches at Hobson, and 4 inches in Great Falls and East Glacier Park.

What forecasters said that 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 17, 7:15 PM MST, 4 hours 45 minutes earlier.

Area forecast discussion, May 17, 7:15 PM MST, 4 hours 45 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
815 PM MDT SAT MAY 17 2003

...WILL UPDATE ZONES AND STATE TO REFLECT HIGHER POPS TONIGHT AND
SUNDAY...

.SHORT TERM...UPPER TROF APPROACHING CWA FROM NORTHWEST.  ENHANCED
CLOUDINESS VIA INFRARED SATELLITE LOOP ALREADY DEVELOPING IN AREA OF
ENHANCED LIFT AHEAD OF THE SYSTEM. THIS SERVING TO MOISTEN THE LOWER
LEVELS WITH DEWPOINTS CLIMBING OVER EASTERN COUNTIES. MIST/DRIZZLE
BEGINNING TO REACH THE GROUND IN GREAT FALLS AS OF 8PM. STAGE IS
SET FOR LIGHT RAIN/SNOW TONIGHT AND SUNDAY ACROSS MUCH OF AREA AS
TROF MOVES IN. HAVE BUMPED UP POPS FOR A NUMBER OF AREAS WITH A
CATEGORICAL FOR ROCKY MOUNTAIN FRONT WHERE PREVIOUS SHIFT PLACED A
MENTION OF SNOW AMOUNTS OVER THE HIGHER TERRAIN. THIS LOOKS GOOD.
WILL HAVE TO KEEP AN EYE ON A POSSIBLE DRY SLOT BUT BELIEVE ENOUGH
MOISTURE WRAPPING AROUND BASE OF TROF TO MAINTAIN GOOD SHOT OF
PRECIPITATION FOR MOST OF AREA. VERY POSSIBLE WE MAY SEE SNOW IN THE
MORNING OVER NORTH CENTRAL MONTANA AND THAT COULD EVEN PERSIST INTO
THE AFTERNOON. DO NOT EXPECT ACCUMULATIONS TO OCCUR. DITTMANN

.EXTENDED...HIGH PRESSURE RIDGE TO BUILD OVER CWA WEDNESDAY...
THURSDAY AND FRIDAY AS NEXT PACIFIC LOW PRESSURE TROUGH DEVELOPS
OVER THE GULF OF ALASKA. AIR MASS UNDER RIDGE EXPECTED TO BE
GENERALLY DRY AND STABLE. RESULT SHOULD BE ONLY ISOLATED SHOWERS
OVER THE MOUNTAINS WITH WARMING TEMPERATURES. TROUGH THEN STARTS TO
MOVE INLAND FRIDAY NIGHT AND SATURDAY. FLOW INTO MONTANA SHIFTS TO
THE SOUTHWEST BECOMING INCREASINGLY MOIST AND UNSTABLE. THIS OPENS
THE POSSIBILITY OF MORE SHOWER ACTIVITY...AGAIN MAINLY OVER THE
MOUNTAINS...WITH TEMPERATURES COOLING A FEW DEGREES.

.CCF NUMBERS
GTF OB 030/042 028/054 032 02462
    BBBBE 060/036 065/040 073/040 078/042 071 00000000000
CTB CB 028/041 028/052 032 02440
    UBBBE 059/036 063/040 070/040 076/042 064 00000000000
HLN OB 034/042 029/055 035 02453
    UBBBB 064/037 067/041 075/041 077/043 070 20001000000
BZN EB 032/043 029/053 031 02553
    BBBBB 060/035 064/038 075/038 076/040 074 20000000-00
WEY EB 024/038 025/048 032 02344
    BBBBB 056/037 059/039 066/039 065/041 067 20000000300
DLN EB 028/038 027/055 032 02244
    BBBBB 060/036 063/039 074/040 072/042 070 20000000000
HVR EB 032/042 031/056 035 02330
    BBBBB 063/039 068/042 075/042 078/044 072 00000000000
LWT OB 033/040 030/051 033 02772
    BBBBB 060/036 064/040 073/040 074/042 071 00000000000

.TFX...NONE.

Hazardous weather outlook, May 17, 1:45 PM MST, 10 hours 15 minutes before

MTZ008>015-044>055-180010-
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
245 PM MDT SAT MAY 17 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND SOUTHWEST
MONTANA

.DAY ONE...TONIGHT

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

NO WATCHES, WARNINGS, OR ADVISORIES CURRENTLY IN EFFECT

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

ON SUNDAY...SNOW IS FORECAST FOR THE GLACIER NATIONAL PARK. TOTAL
SNOW ACCUMULATIONS OF 2 TO 5 INCHES IS POSSIBLE AGAIN BY SUNDAY
NIGHT. WEATHER CONDITIONS WILL IMPROVE WITH A DRYING TREND MONDAY
THROUGH FRIDAY.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

Event by event

5 winter storm. Local standard time, as filed.

Winter Storm, Chouteau

When: May 18, 12:00 AM MST to 6:00 PM MST
Where: Chouteau forecast zone
Reported by: TRAINED SPOTTER

Winter Storm, Cascade

When: May 18, 12:00 AM MST to 6:00 PM MST
Where: Cascade forecast zone
Reported by: TRAINED SPOTTER

Winter Storm, Judith Basin

When: May 18, 12:00 AM MST to 6:00 PM MST
Where: Judith Basin forecast zone
Reported by: TRAINED SPOTTER

Winter Storm, Fergus

When: May 18, 12:00 AM MST to 6:00 PM MST
Where: Fergus forecast zone
Reported by: TRAINED SPOTTER

Winter Storm, North Rocky Mountain Front

When: May 18, 12:00 AM MST to 6:00 PM MST
Where: North Rocky Mountain Front forecast zone
Reported by: TRAINED SPOTTER

What these are

Winter Storm: A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Montana in 2003 Every state in 2003 This day in weather history Warnings in Montana, May 2003

Sources

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: 5358283, 5358284, 5358285, 5358286, 5358287.