Alert archive / Montana / Severe Thunderstorm Warnings in 2001
Severe Thunderstorm Warning 66, NWS Great Falls, MT
NWS Great Falls, MT issued this severe thunderstorm warning at Jul 21, 2001, 4:45 PM MDT for Blaine County, Montana. It was in force for 45 min. No storm report in the archive falls 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.
The facts
- Issued
- Jul 21, 2001, 4:45 PM MDT (22:45 UTC)
- Expired
- Jul 21, 2001, 5:30 PM MDT
- In force
- 45 min
- Issued by
- NWS Great Falls, MT
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
County Blaine County, MT
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jul 21, 3:15 PM MDT | Tornado Watch | SPC | 6 hr |
The nearest sounding before it
Great_falls, MT (KTFX), launched 12:00Z, 10.8 hours before the alert went out and 116 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
- 21 J/kg
- Mixed-layer CIN
- -341 J/kg
- Mixed-layer LCL
- 1692 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- -53 m²/s²
- 0-3 km storm-relative helicity
- 75 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 WUUS55 KTFX 212246 SVRGTF MTC005-212330- BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE GREAT FALLS MT 445 PM MDT SAT JUL 21 2001 THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... SOUTHERN BLAINE COUNTY IN NORTH CENTRAL MONTANA * UNTIL 530 PM MDT * AT 439 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM OVER EXTREME SOUTHWESTERN BLAINE COUNTY...OR ABOUT 46 MILES SOUTHEAST OF BIG SANDY...MOVING EAST AT 35 MPH. * THE SEVERE THUNDERSTORM WILL BE NEAR... RURAL SOUTHERN BLAINE COUNTY AT 500 PM MDT A TORNADO WATCH REMAINS IN EFFECT UNTIL 900 PM MDT SATURDAY EVENING FOR NORTH CENTRAL MONTANA. REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN GREAT FALLS. LAT...LON 4795 10943 4779 10937 4782 10889 4807 10889 h
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 21, 3:00 PM MDT, 1 hour 45 minutes earlier.
Area forecast discussion, Jul 21, 3:00 PM MDT, 1 hour 45 minutes before
SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 300 PM MDT SAT JUL 21 2001 ACCORDING TO MODELS LOOKS LIKE THERE WILL BE A CHANGE TO CURRENT PATTERN OF SW FLOW ALOFT WITH SEVERE WEATHER EPISODES E OF THE CONTINENTAL DIVIDE. FOR TONIGHT...AIRMASS IS UNSTABLE ONCE AGAIN OVER AREA AND EVEN A LITTLE MORE UNSTABLE THAN EARLY FRI AFTERNOON. MSAS DATA INDICATES A MOISTURE CONVERGENCE AREA FROM SW TO N CENTRAL MT AT 19Z. APPEARS TO BE ENOUGH SHEAR FOR ORGANIZED STORMS BUT NOT NECESSARILY SUPERCELLS. THE PROBLEM LIKE FRIDAY NIGHT IS THAT MODELS DO NOT INDICATE ANY SIGNIFICANT SHORTWAVES AFFECTING FORECAST AREA. STILL WITH QUITE AN UNSTABLE AIRMASS WILL GO WITH HIGH SCATTERED TO LOW LIKELY POPS OVER MOST OF AREA. IN THE FAR NW WILL GO WITH SLIGHT CHANCE POPS AS THAT AREA IS FORECAST TO BE IN A DRIER AIRMASS. FOR SUNDAY...ETA AND AVN DIFFER SIGNIFICANTLY WITH REMNANTS OF PAC NW UPPER TROUGH MOVING THROUGH THE AREA. PREFER THE SLOWER AND WEAKER ETA AS THE AVN/MRF HAS HAD A TENDENCY TO BE TOO STRONG AND FAST WITH SHORTWAVES MOVING TOWARDS AN UPPER RIDGE. WILL GO WITH 20 AND 30 PCT POPS AS MOISTURE AND LIFT AHEAD OF FEATURE ARE NOT VERY IMPRESSIVE. FORECAST SOUNDINGS STILL INDICATE SOME INSTABILITY DURING THE AFTERNOON BUT IT IS QUITE A BIT LESS THAN THAT OF TODAY. FOR MONDAY...BOTH ETA AND AVN FORECAST A STRONGLY POSITIVELY TILTED SHORTWAVE FROM SW SASK THROUGH NW MT TO ERN OREGON. AREA IS MAINLY UNDER WLY CONFLUENT FLOW ALOFT WITH LITTLE IN THE WAY OF SHORTWAVE ACTIVITY. AIRMASS IS ALSO NOT ALL THAT MOIST. WAS TEMPTED TO GO DRY BUT MODELS DO INDICATE SOME WEAK INSTABILITY SO WILL GO WITH BROADBRUSH 20 PCT POPS. AVN QPF FOR MON LOOKS OVERDONE. BLANK .EXTENDED... ON TUESDAY THE TROUGH CONTINUES OVER THE WESTERN US WITH MINOR SHORT WAVES MOVING THROUGH THE MEAN SW FLOW. THE TROUGH LOOKS LIKE IT WILL MOVE EAST ON WEDNESDAY WITH YET ANOTHER TROUGH MOVING THROUGH SOUTHERN CANADA ON THU/FRI. THOUGH THE FLOW ALOFT BECOMES MORE WESTERLY BY THURSDAY...THE SHORTWAVE MOVING THROUGH ON THU/FRI WILL KEEP A CHANCE OF AFTERNOON/EVENING STORMS IN FORECAST THROUGH FRI. WITH NORTHWEST FLOW BY SAT...SHOULD BE DRYING OUT THEN. CCF NUMBERS GTF BB 055/078 050/078 048 04522 CTB BB 050/075 047/075 045 04221 HLN BB 054/080 051/080 050 04522 BZN BB 051/080 047/080 047 04431 WEY BB 046/075 042/076 042 04432 DLN BB 049/077 043/077 044 04421 HVR EB 060/088 054/088 052 04532 LWT EB 056/077 048/077 046 04632=
The office that day
Everything else NWS Great Falls, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 20, 8:08 PM MDT | Severe Thunderstorm Warning | TFX | Fergus | 67 min |
| 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, 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; the sounding from the Mesonet's radiosonde archive.