Alert archive / Montana / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 56, NWS Glasgow, MT

July 7, 2011Garfield County, Petroleum County, Montana

NWS Glasgow, MT issued this severe thunderstorm warning at Jul 7, 2011, 10:27 AM MDT for Garfield County, Petroleum County, Montana. It was in force for 40 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 7, 2011, 10:27 AM MDT (16:27 UTC)
Expired: Jul 7, 2011, 11:07 AM MDT
In force: 40 min
Issued by: NWS Glasgow, MT
Area: Storm-based polygon

Counties Garfield County, MT, Petroleum County, MT

The radar

The Glasgow radar (KGGW), 135 km from the middle of the area, began a volume at 16:27 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

Great_falls, MT (KTFX), launched 12:00Z, 4.5 hours before the alert went out and 226 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 874 J/kg
Mixed-layer CIN: -164 J/kg
Mixed-layer LCL: 1766 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 4 m²/s²
0-3 km storm-relative helicity: 55 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Jul 7, 10:08 AM MDT, 19 minutes earlier.

Area forecast discussion, Jul 7, 10:08 AM MDT, 19 minutes before

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Hazardous weather outlook, Jul 7, 9:50 AM MDT, 37 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
950 AM MDT THU JUL 7 2011

MTZ024>027-081200-
RICHLAND-DAWSON-PRAIRIE-WIBAUX-
950 AM MDT THU JUL 7 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...TODAY AND TONIGHT

THE YELLOWSTONE RIVER WILL CONTINUE TO RUN HIGH THE NEXT FEW
DAYS. RIVER LEVELS WILL RUN WITHIN A FOOT OF FLOOD STAGE AT SIDNEY
AND TWO FEET OF FLOOD STAGE AT GLENDIVE TODAY. THE RIVER WILL THEN
SLOWLY FALL OR REMAIN STEADY THROUGH THE WEEKEND.

RANCHERS AND WATER USERS MAY WANT TO TAKE PRECAUTIONS IF THE
HIGHER RIVER LEVELS AFFECT THEIR OPERATIONS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

A COLD FRONT WILL MOVE THROUGH THE REGION ON FRIDAY WITH A GOOD
CHANCE OF THUNDERSTORMS. SOME STORMS MAY BECOME SEVERE WITH LARGE
HAIL AND DAMAGING WINDS ESPECIALLY IN THE AFTERNOON AND EVENING.

.SPOTTER INFORMATION STATEMENT...

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

MTZ016>023-059>062-081200-
CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY-
DANIELS-SHERIDAN-WESTERN ROOSEVELT-PETROLEUM-GARFIELD-MCCONE-
NORTHERN PHILLIPS-SOUTHWEST PHILLIPS-NORTHERN VALLEY-
EASTERN ROOSEVELT-
950 AM MDT THU JUL 7 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...TODAY AND TONIGHT

SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS
SOUTHERN PHILLIPS...PETROLEUM COUNTY AND WESTERN GARFIELD THIS
MORNING AND AFTERNOON. SOME STORMS COULD BE STRONG TO SEVERE AND
PRODUCE HAIL AND PERIODS OF HEAVY RAIN.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

A COLD FRONT WILL MOVE THROUGH THE REGION ON FRIDAY WITH A GOOD
CHANCE OF THUNDERSTORMS. SOME STORMS MAY BECOME SEVERE WITH LARGE
HAIL AND DAMAGING WINDS ESPECIALLY IN THE AFTERNOON AND EVENING.

WESTERLY WIND BEHIND THE COLD FRONT WILL INCREASE SATURDAY TO 15
TO 25 MPH. THIS MAY REQUIRED A WIND ADVISORY FOR FORT PECK LAKE.

.SPOTTER INFORMATION STATEMENT...

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

In the hours before

Special weather statement, Jul 7, 9:20 AM MDT, 1 hour 7 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GLASGOW MT
920 AM MDT THU JUL 7 2011

MTZ021-071545-
PETROLEUM-
920 AM MDT THU JUL 7 2011

THE NATIONAL WEATHER SERVICE IN GLASGOW HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  WESTERN PETROLEUM COUNTY IN NORTHEAST MONTANA...

UNTIL 945 AM MDT.

AT 913 AM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 14 MILES SOUTHEAST OF ROY...MOVING NORTHEAST AT
30 MPH.

HAIL UP TO THE SIZE OF NICKELS AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH FREQUENT DANGEROUS LIGHTNING.

LOCATIONS IN THE ADVISORY INCLUDE...
  RURAL AREAS OF WESTERN PETROLEUM COUNTY...
  RURAL AREAS OF CENTRAL PETROLEUM COUNTY...

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS NOAA WEATHER RADIO...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

LAT...LON 4719 10872 4727 10873 4728 10860 4731 10859
      4731 10835 4735 10831 4713 10820 4692 10861
      4709 10862 4709 10871 4710 10875 4718 10875
TIME...MOT...LOC 1519Z 236DEG 25KT 4727 10864

GILCHRIST
WEATHER.GOV/GLASGOW

Local storm report, Jul 7, 10:03 AM MDT, 24 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 9:20 AM MDT	Special Weather Statement	GGW	Petroleum	25 min
Jul 7, 9:41 AM MDT	Severe Thunderstorm Warning	GGW	Petroleum	64 min

Nearby

Severe Thunderstorm Warnings in Montana, 2011 Every severe thunderstorm 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.