Alert archive / Montana / Winter Storm Warnings in 2011

Winter Storm Warning 7, NWS Glasgow, MT

April 22, 2011Petroleum County, Wibaux County, Montana

NWS Glasgow, MT issued this winter storm warning at Apr 22, 2011, 4:07 AM MDT for Petroleum County, Wibaux County, Montana. It was in force for 16 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Apr 22, 2011, 4:07 AM MDT (10:07 UTC)
Expired
Apr 22, 2011, 8:25 PM MDT
In force
16 hr
Issued by
NWS Glasgow, MT

Counties Petroleum County, MT, Wibaux County, MT

The radar

The Glasgow radar (KGGW), 133 km from the middle of the area, began a volume at 10:06 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Rapid City, SD (KUNR), launched 00:00Z, 10.1 hours before the alert went out and 422 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Rapid City, SD at 00:00Z on 2011-04-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 423 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Rapid City, SD at 00:00Z on 2011-04-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 77 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
423 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
1630 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
77 m²/s²
0-3 km storm-relative helicity
178 m²/s²
Significant tornado parameter
0.1
Supercell composite
3.2

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this winter storm warning went out, 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 this winter storm warning went out at Apr 22, 3:43 AM MDT, 24 minutes earlier.

Area forecast discussion, Apr 22, 3:43 AM MDT, 24 minutes before
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Hazardous weather outlook, Apr 21, 3:02 PM MDT, 13 hours 5 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
302 PM MDT THU APR 21 2011

MTZ016-017-059-061-221200-
CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY-
NORTHERN PHILLIPS-NORTHERN VALLEY-
302 PM MDT THU APR 21 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A FLOOD WARNING REMAINS IN EFFECT FOR VALLEY AND NORTHEAST
PHILLIPS COUNTIES. FLOODING WILL CONTINUE ON THE MILK RIVER AND
THE NORTHERN TRIBUTARIES FOR THE NEXT FEW WEEKS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

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

MTZ021>027-060-221200-
PETROLEUM-GARFIELD-MCCONE-RICHLAND-DAWSON-PRAIRIE-WIBAUX-
SOUTHWEST PHILLIPS-
302 PM MDT THU APR 21 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

NO HAZARDOUS WEATHER EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

A STORM SYSTEM WILL AFFECT THE AREA TONIGHT AND FRIDAY. THERE IS
A POTENTIAL FOR ACCUMULATING SNOW...DEPENDING ON TEMPERATURES
FRIDAY. THE AREAS MOST LIKELY TO SEE ACCUMULATING SNOW FROM THIS
STORM WILL BE HIGHER ELEVATION AREAS LIKE THE LITTLE ROCKY
MOUNTAINS...BIG SHEEP MOUNTAINS...WIBAUX...PETROLEUM AND WESTERN
GARFIELD COUNTIES. A WINTER WEATHER ADVISORY IS IN EFFECT FOR
WIBAUX COUNTY FOR FRIDAY AND FRIDAY EVENING.

.SPOTTER INFORMATION STATEMENT...

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

The office that day

Everything else NWS Glasgow, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 22, 4:07 AM MDTWinter Weather AdvisoryGGWDawson, Garfield, McCone, Phillips, Prairie, Richland11 hr

Nearby

Winter Storm Warnings in Montana, 2011Every winter storm warning in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.