Winter Storm in Montana, April 18, 2003

Name: Winter Storm in Montana, April 18, 2003
Start: 2003-04-18T03:00
End: 2003-04-18T13:00
Location: Montana

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

A winter storm affected the mountain areas of Central and Southwest Montana on the 18th. Here is a list of some of the snowfalls reported:12 inches at Neihart 10S; 8 inches at Bozeman 30SW; and 6 inches at Moore 10SE.

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 winter storm affected the mountain areas of Central and Southwest Montana on the 18th. The heaviest snow fell above 5000 feet.Here is a list of some of the snowfalls reported:12 inches at Neihart 10S; 8 inches at Bozeman 30SW; and 6 inches at Moore 10SE.

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 Apr 18, 2:45 AM MST, 15 minutes earlier.

Area forecast discussion, Apr 18, 2:45 AM MST, 15 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
345 AM MDT FRI APR 18 2003

.SHORT TERM...RAIN AND SNOW ALREADY FALLING IN A FAIRLY NARROW BAND
FROM SOUTHERN BEAVERHEAD AND MADISON COUNTIES NORTH-NORTHEAST UP TO
HAVRE...WITH GREAT FALLS AND LEWISTOWN THE WESTERN AND EASTERN
BOUNDARIES RESPECTIVELY. MESOETA HAD A GOOD HANDLE ON THE
PRECIPITATION IN THE SOUTHWEST...WITH BZN ALREADY GETTING OVER
THREE QUARTERS OF AN INCH SINCE MIDNIGHT. PRECIPITATION HAS CHANGED
OVER TO SNOW IN THE SOUTHWEST AND IN THE HIGHER ELEVATIONS...WITH A
RAIN/SNOW MIX FARTHER NORTH. HAVE ALREADY EXPANDED THE WINTER STORM
WARNING ABOVE 5000 FEET TO INCLUDE GALLATIN...BROADWATER...AND
MEAGHER COUNTIES THROUGH THIS MORNING. MODELS INDICATE LIFT AND
ASSOCIATED DISTURBANCE LIFTING TO THE NORTHEAST OUT OF SOUTHWEST
MONTANA THIS MORNING...SO TIMING OF WARNING LOOKS GOOD. SNOW IN
JUDITH BASIN COUNTY THIS MORNING SHOULD SPREAD EAST INTO FERGUS
COUNTY THIS MORNING AND CONTINUE THROUGH THE DAY AS THE DISTURBANCE
MOVES OVERHEAD...SO WARNING THERE ABOVE 5000 FEET THROUGH TODAY
LOOKS GOOD AS WELL. CLOUDS AND SHOWERS ACROSS MOST OF THE AREA
TODAY SHOULD KEEP TEMPERATURES COOLER THAN YESTERDAY...IN THE 40S TO
LOWER 50S. A SURFACE LOW JUST EAST OF THE CENTRAL ROCKIES WILL ALSO
KEEP LIGHT NORTHWEST UPSLOPE WINDS ACROSS THE AREA. THE DISTURBANCE
MOVES EAST OF THE TFX CWA TONIGHT AND DRIER AIR MOVES IN WITH AN
UPPER TROUGH...FOR DECREASING CLOUDS AND POPS...ALONG WITH COOLER
OVERNIGHT LOWS. THE TROUGH WEAKENS ON SATURDAY...ALLOWING AN UPPER
RIDGE TO BUILD OVER THE AREA FOR SATURDAY THROUGH SUNDAY. THIS WILL
CONTINUE DRY CONDITIONS WITH WARMING TEMPERATURES OVER THE WEEKEND.
WEAK HIGH PRESSURE AT THE SURFACE AS WELL WILL KEEP WINDS LIGHT.
COULSTON

.EXTENDED...RATHER UNSETTLED SPRING PATTERN SETTING UP FOR THE
PERIOD. MOISTURE AND INSTABILITY WILL INCREASE ON MONDAY AS AN UPPER
LEVEL RIDGE MOVES INTO EASTERN MONTANA...ALLOWING FOR SOUTHERLY FLOW
ALOFT TO INVADE MONTANA. LOW LEVEL SOUTHEAST FLOW WILL INCREASE ON
TUESDAY...PUMPING IN MORE MOISTURE TO THE AREA. WITH A BROAD UPPER
LEVEL TROUGH TAKING RESIDENCE IN THE WESTERN U.S...EMBEDDED
DISTURBANCES IN THE SOUTHERLY FLOW ALOFT WILL SET UP A SHOWERY
PATTERN WITH AFTERNOON AND EVENING THUNDERSTORMS A GOOD BET. PATTERN
REMAINS SOMEWHAT STAGNANT THROUGH THURSDAY WITH INSTABILITY SHOWERS
CONTINUING. TEMPERATURES WILL REMAIN SEASONABLE THROUGH THE PERIOD
WITH A SLIGHT COOLING TREND TOWARDS MID WEEK. VILLANI

.CCF NUMBERS
GTF OB 050/029 057/033 063 10610
    BBEEB 036/064 037/060 035/059 035/059 0000233330
CTB BB 048/027 057/032 060 10320
    BBEEB 035/061 035/055 033/056 033/056 0000233330
HLN OB 048/031 057/033 065 10620
    BBEEB 035/064 038/060 036/057 036/060 0003333332
BZN SB 047/027 056/030 061 10+20
    BBEEB 031/062 035/061 033/057 031/059 0003333332
WEY SB 038/018 044/019 048 10830
    BBEEB 027/052 032/053 030/051 030/051 0003344442
DLN RB 045/025 056/029 059 10620
    BEEEE 033/058 035/055 032/054 032/053 0004433443
HVR OB 056/033 058/034 066 10630
    BBEEB 038/069 039/066 037/063 036/064 0000033330
LWT OB 048/029 052/032 060 10740
    BBEEB 034/063 037/062 035/057 034/058 0000033330

.TFX...WINTER STORM WARNING ABOVE 5000 FEET GALLATIN BROADWATER AND
       MEAGHER COUNTIES THROUGH THIS MORNING (ZONES 53 54 55)
    ...WINTER STORM WARNING ABOVE 5000 FEET JUDITH BASIN AND
       FERGUS COUNTIES TODAY (ZONES 50 51)

Hazardous weather outlook, Apr 17, 3:31 AM MST, 23 hours 29 minutes before

MTZ008>015-044>055-180010-
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
431 AM MDT THU APR 17 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND SOUTHWEST
MONTANA

.DAY ONE...TODAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

Event by event

5 winter storm. Local standard time, as filed.

Winter Storm, Cascade

When: April 18, 3:00 AM MST to 1:00 PM MST
Where: Cascade forecast zone
Reported by: TRAINED SPOTTER

Winter Storm, Judith Basin

When: April 18, 3:00 AM MST to 1:00 PM MST
Where: Judith Basin forecast zone
Reported by: TRAINED SPOTTER

Winter Storm, Fergus

When: April 18, 3:00 AM MST to 1:00 PM MST
Where: Fergus forecast zone
Reported by: TRAINED SPOTTER

Winter Storm, Meagher

When: April 18, 3:00 AM MST to 1:00 PM MST
Where: Meagher forecast zone
Reported by: TRAINED SPOTTER

Winter Storm, Gallatin

When: April 18, 3:00 AM MST to 1:00 PM MST
Where: Gallatin 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, April 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: 5348113, 5348114, 5348115, 5348116, 5348117.