Alert archive / Montana / Severe Thunderstorm Warnings in 2001
Severe Thunderstorm Warning 61, NWS Great Falls, MT
NWS Great Falls, MT issued this severe thunderstorm warning at Jul 20, 2001, 8:08 PM MDT for Fergus County, Montana. It was in force for 67 min. 1 report came from inside the area while it was in force.
The area
The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties, with what was reported inside it.
The facts
- Issued
- Jul 20, 2001, 8:08 PM MDT (02:08 UTC)
- Expired
- Jul 20, 2001, 9:15 PM MDT
- In force
- 67 min
- Issued by
- NWS Great Falls, MT
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
County Fergus County, MT
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 20, 8:15 PM MDT | Hail 3 | Hilger, MT | Actual spotter location Hilger 5 N...Near total crop damage (monetary total of crop damage unknown). |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.
The nearest sounding before it
Great_falls, MT (KTFX), launched 00:00Z, 2.1 hours before the alert went out and 104 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.
- Mixed-layer CAPE
- 245 J/kg
- Mixed-layer CIN
- -8 J/kg
- Mixed-layer LCL
- 2721 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 21 m²/s²
- 0-3 km storm-relative helicity
- 32 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted, in the capitals the NWS used until 2016.
000 WUUS55 KTFX 210210 SVRGTF MTC027-210315- BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE GREAT FALLS MT 808 PM MDT FRI JUL 20 2001 THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... FERGUS COUNTY IN CENTRAL MONTANA THIS INCLUDES THE CITY OF LEWISTOWN * UNTIL 915 PM MDT * AT 806 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 6 MILES NORTH OF LEWISTOWN...MOVING NORTHEAST AT 15 MPH. * THE SEVERE THUNDERSTORM WILL BE NEAR... HILGER AT 815 PM MDT AND 5 MILES NORTH OF GRASS RANGE AT 850 PM MDT LARGE HAIL AND WINDS OVER 60 MPH ARE EXPECTED WITH THIS STORM. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES. TAKE SHELTER IN A REINFORCED BUILDING. REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICEd IN GREAT FALLS. LAT...LON 4720 10961 4700 10954 4707 10877 4764 10883
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 Great Falls, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 20, 3:00 PM MDT, 5 hours 8 minutes earlier.
Area forecast discussion, Jul 20, 3:00 PM MDT, 5 hours 8 minutes before
SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 300 PM MDT FRI JUL 20 2001 SEEMINGLY PERMANENT PATTERN OF EMBEDDED SHORTWAVES IN A SW FLOW ALOFT TO CONTINUE THROUGH SAT NIGHT WITH AIRMASS CONTINUING UNSTABLE. MODELS CONTINUE TO BE DIFFERENT FROM ONE ANOTHER ON SHORTWAVE DETAILS AND ALSO DIFFER FROM RUN TO RUN ON THEIR DETAILS. SO ALTHOUGH AIRMASS WILL CONTINUE TO BE UNSTABLE AND SOMEWHAT MOIST WILL KEEP POPS IN THE SCATTERED CATEGORY THROUGH THE 1ST THREE FORECAST PERIODS. AS FOR SEVERE WEATHER...FOR TONIGHT...AT 18Z SATELLITE IMAGERY INDICATED A VORTICITY CENTER OVER NE OREGON WITH A SHORTWAVE EXTENDING SW THROUGH SE OREGON. ETA/MESOETA ARE BETTER THAN THE NGM AND AVN IN THE HANDLING OF THIS FEATURE. THERE IS A JET STREAK ASSOCIATED WITH THE FEATURE AND SOME THUNDERSTORMS ARE BREAKING OUT IN IN THE RIGHT REAR QUADRANT OF THE JET STREAK. EXPECT THUNDERSTORMS TO CONTINUE TO MOVE NE TOWARDS CENTRAL MT AND THEY MAY INTENSIFY AS THEY MOVE INTO THE MORE UNSTABLE AIRMASS THERE. CAPES SHOULD BE AROUND 1000/1500 JOULES/KG. PROBLEM IS ETA/MESOETA HAVE ONLY A VERY WEAK SHORTWAVE ASSOCIATED WITH THESE THUNDERSTORMS. MESOETA DOES HAVE A STRONGER SHORTWAVE MOVING NE THROUGH THE AREA LATER THIS EVENING AND AFTER MIDNIGHT BUT THE PROBLEM IS THAT SHORTWAVE WILL BE MOVING THROUGH AFTER INSOLATION WILL HAVE GONE. SO UPSHOT IS NOT SURE HOW MUCH SEVERE WEATHER THERE WILL BE TONIGHT. SPC HAS CENTRAL ZONES UNDER A RISK OF SEVERE WEATHER AGAIN SAT AFTERNOON AND NIGHT. AGAIN THIS WILL REMAIN A POSSIBILITY AS AIRMASS WILL BE QUITE UNSTABLE. TO AID IN THUNDERSTORM DEVELOPMENT MODELS INDICATE SOME POSSIBLE INTERACTION BETWEEN LEFT FRONT AND RIGHT REAR QUADRANTS OF TWO SEPARATE JET STREAKS. LOOKING AHEAD TO SUN PATTERN CHANGES A LITTLE AS FLOW ALOFT BECOMES MORE ZONAL. ETA HINTS AT WEAK RIDGING ALOFT WHILE AVN HAS CYCLONIC WSW FLOW ALOFT. MODELS HINT AT SOME POSSIBLE SHORTWAVE ACTIVITY ACROSS THE N WHILE CHECK OF FORECAST SOUNDINGS INDICATES AIRMASS SHOULD BE WEAKLY UNSTABLE OVER ENTIRE AREA. WILL GO WITH 20 PCT POPS BUT GO 30 PCT AT HVR. THE REASON FOR GOING A LITTLE HIGHER THERE IS THEY APPEAR TO BE IN A LITTLE BETTER POSITION GO GET LIFT FROM SHORTWAVE DYNAMICS. .EXTENDED... UPPER LEVEL TROF IS FORECASTED TO MOVE OVER NORTH CENTRAL MONTANA BY MONDAY AND DISSIPATE...AS UPPER LEVEL FLOW BECOMES MORE ZONAL. THIS WILL RESULT IN MOSTLY DRY CONDITIONS TUESDAY AND WEDNESDAY WITH NEAR NORMAL TEMPERATURES. BY THURSDAY A NEW UPPER LEVEL TROF AND CANADIAN COLD FRONT IS EXPECTED TO DIP DOWN INTO FAR NORTH CENTRAL MONTANA. THIS WILL RESULT IN ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ACROSS THE REGION...WITH SLIGHTLY BELOW NORMAL TEMPERATURES OVER THE NORTH AND NEAR NORMAL TEMPERATURES IN THE SOUTH. BRUSDA CCF NUMBERS GTF EB 055/080 053/078 048 04444 CTB BB 050/077 050/075 046 04323 HLN EB 053/082 053/080 048 04444 BZN BB 051/083 048/080 045 04444 WEY BB 046/078 043/075 040 04333 DLN BB 052/079 049/077 047 04433 HVR EE 060/088 060/085 052 04544 LWT BB 055/082 053/077 047 04545=
The office that day
Everything else NWS Great Falls, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 2:41 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau | 49 min |
| Jul 21, 3:32 PM MDT | Severe Thunderstorm Warning | TFX | Judith Basin | 43 min |
| Jul 21, 3:54 PM MDT | Severe Thunderstorm Warning | TFX | Fergus | 51 min |
| Jul 21, 4:33 PM MDT | Severe Thunderstorm Warning | TFX | Judith Basin | 42 min |
| Jul 21, 4:45 PM MDT | Severe Thunderstorm Warning | TFX | Blaine | 45 min |
| Jul 21, 5:04 PM MDT | Severe Thunderstorm Warning | TFX | Fergus | 56 min |
Nearby
Severe Thunderstorm Warnings in Montana, 2001Every severe thunderstorm warning in 2001
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.