Alert archive / Montana / Flash Flood Warnings in 1991
Flash Flood Warning 2, NWS Great Falls, MT
NWS Great Falls, MT issued this flash flood warning at May 20, 1991, 6:45 PM MDT for Blaine County, Hill County, Montana. It was in force for 3 hr.
The area
The counties it named.
The facts
- Issued
- May 20, 1991, 6:45 PM MDT (00:45 UTC)
- Expired
- May 20, 1991, 9:50 PM MDT
- In force
- 3 hr
- Issued by
- NWS Great Falls, MT
- Area
- Whole counties
Counties Blaine County, MT, Hill County, MT
The nearest sounding before it
Great Falls, MT (KGTF), launched 00:00Z, 0.8 hours before the alert went out and 176 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2068 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- -4 m²/s²
- 0-3 km storm-relative helicity
- 13 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KHVR 210046 COR FFWHVR MTC041-005-210300- BULLETIN - EBS ACTIVATION REQUESTED FLASH FLOOD WARNING...CORRECTION EXPIRATION TIME. NATIONAL WEATHER SERVICE HAVRE MT 645 PM MDT MON MAY 20 1991 THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING EFFECTIVE UNTIL 900 PM MDT FOR PERSONS IN THE FOLLOWING MONTANA COUNTIES... IN NORTH-CENTRAL MONTANA...SOUTHERN HILL AND SOUTHERN BLAINE ...FOR THE BEAR PAWS...INCLUDING BEAVER CREEK PARK...AND ALSO THE TOWN OF...ROCKY BOY. THUNDERSTORMS WITH VERY HEAVY RAIN WERE OCCURRING IN THE BEAR PAWS...SEVERAL REPORTS OF AN INCH OF RAIN WITHIN A FEW MINUTES. ROADS WERE REPORTED UNDER WATER AT ROCKY BOY...WITH QUICKLY RISING WATERS IN OTHER LOCATIONS. RADAR REPORTS SHOWED THE THUNDERSTORMS WERE MOVING SLOWLY NORTH...WITH HEAVY RAINS LIKELY TO LAST ANOTHER HOUR. A FLASH FLOOD WARNING MEANS FLOODING IS IMMINENT OR HAS BEEN REPORTED. TAKE NECESSARY PRECAUTIONS AS REQUIRED IMMEDIATELY. DO NOT ATTEMPT TOa DRIVE ACROSS FLOODED ROADWAYS. MOVE TO HIGHER GROUND.
What forecasters said that day
The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
In the hours before
Special weather statement, May 20, 3:43 PM MDT, 3 hours 2 minutes before
MTZ004-202245- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE HELENA MT 342 PM MDT MON MAY 20 1991 ...SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 9 PM MDT FOR PORTIONS OF SOUTHWEST AND CENTRAL MONTANA... AT 330 PM MDT AN AREA OF THUNDERSTORMS WAS IN THE HELENA AREA. THESE STORMS HAVE PRODUCED WINDS TO 35 MPH... AND NUMEROUS LIGHTNING STRIKES. ANOTHER AREA OF STRONGER STORMS WAS JUST BARELY ON THE NORTH BORDER OF MEAGHER COUNTY. ANOTHER STORM WAS LOCATED WEST OF AUGUSTA IN EXTREME NORTHERN LEWIS AND CLARK COUNTY. ALL OF THESE STORMS ARE MOVING NORTH AT 25 MPH. WHILE NO SEVERE WEATHER HAS BEEN REPORTED FROM THESE STORMS IT IS VERY POSSIBLE THAT THOSE IN THE WATCH AREA COULD PRODUCE SEVERE WEATHER. IF YOU SEE SEVERE WEATHER CONTACT YOUR SHERIFF'S OFFICE OR THE NWS AT 449-5204. ROSS
Special weather statement, May 20, 4:58 PM MDT, 1 hour 47 minutes before
MTZ005-220000- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE HAVRE MT 505 PM MDT MON MAY 20 1991 ...SEVERE THUNDERSTORM WATCH UNTIL 9 PM FOR PARTS OF NORTH-CENTRAL MONTANA... AS OF 445 PM...LIGHTNING STRIKE CHARTS AND RADAR REPORTS SHOWED NUMEROUS STRONG THUNDERSTORMS MOVING INTO NORTH-CENTRAL MONTANA. THESE ARE MOVING RATHER SLOWLY TO THE NORTH...AT 20 MPH. WHILE NO SEVERE WEATHER HAS BEEN REPORTED IN NORTH-CENTRAL MONTANA...SMALL HAIL AND HEAVY SHOWERS HAVE OCCURRED...LIKELY TO CONTINUE INTO THE EVENING. A FEW SEVERE THUNDERSTORMS HAVE OCCURRED IN SOUTH-CENTRAL AND CENTRAL MONTANA. THE NEAREST ONE IN FERGUS COUNTY HAS WEAKENED HOWEVER. THE SEVERE THUNDERSTORM WATCH CONTINUES FOR HILL...BLAINE...CHOUTEAU AND PHILLIPS COUNTIES...AS WELL AS MUCH OF THE CENTRAL THIRD OF MONTANA. LARGE HAIL...DAMAGING WINDS...HEAVY SHOWERS...AND FREQUENT LIGHTNING STRIKES ARE POSSIBLE. LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS ON T%HESE STORMS. SIMONSEN
Special weather statement, May 20, 5:18 PM MDT, 1 hour 27 minutes before
MTZ004-210015- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE HELENA MT 519 PM MDT MON MAY 20 1991 ...SEVERE THUNDERSTORM WATCH UNTIL 9PM MDT FOR MEAGHER AND GALLATIN COUNTIES... MEAGHER AND GALLATIN COUNTIES REMAIN IN A SEVERE THUNDERSTORM WATCH AREA UNTIL 9PM THIS MONDAY EVENING. A LINE OF THUNDERSTORMS MOVED THROUGH MEAGHER COUNTY IN THE PAST 2 HOURS AND THERE ARE A FEW THUNDERSTORMS IN GALLATIN COUNTY. RADAR SHOWED THE STORMS THAT PASSED THROUGH MEAGHER COUNTY TO BE VERY STRONG BUT NO REPORTS OF SEVERE WEATHER HAVE BEEN RECEIVED. WHILE NO THUNDERSTORMS APPROACHING SEVERE ARE OBSERVED IN EITHER OF THESE TWO COUNTIES AT THIS TIME...DEVELOPMENT IS POSSIBLE. IF THREATENING WEATHER APPROACHES PEOPLE SHOULD FIND SHELTER IN A STURDY BUILDING.
Local storm report, May 20, 5:41 PM MDT, 1 hour 4 minutes before
STORM REPORT NATIONAL WEATHER SERVICE GREAT FALLS, MT 539 PM MDT MON MAY 20 1991 TIME PLACE EVENT 430PM MDT 10MI SE OF FORT BENTON GOLF-BALL SIZED HAIL
Special weather statement, May 20, 5:46 PM MDT, 59 minutes before
MTZ004-210145- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE HELENA MT 547 PM MDT MON MAY 20 1991 ...SEVERE THUNDERSTORM WATCH FOR MEAGHER AND GALLATIN COUNTIES IS CANCELLED... AS 545 PM MDT THE THREAT OF SEVERE WEATHER NO LONGER EXISTED IN MEAGHER AND GALLATIN COUNTIES. THE WATCH FOR OTHER PORTIONS OF CENTRAL MONTANA IS STILL IN EFFECT UNTIL 9PM MDT. THERE ARE STILL A FEW RAINSHOWERS AND THUNDERSTORMS IN THESE COUNTIES BUT THEY ARE NOT EXPECTED TO BE VERY STRONG. REPEAT...THE WATCH IN MEAGHER AND GALLATIN COUNTIES IS CANCELLED BUT REMAINS IN EFFECT FOR OTHER PORTIONS OF CENTRAL MONTANA. ROSS
Special weather statement, May 20, 6:17 PM MDT, 28 minutes before
MTZ003-005-210115- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GREAT FALLS MT 615 PM MDT MON MAY 20 1991 AT 6PM MDT RADAR INDICATED A LINE OF THUNDERSTORMS STRETCHING FROM NEAR CONRAD IN EASTERN PONDERA COUNTY ACROSS ALL OF NORTHERN CHOUTEAU COUNTY. THE THUNDERSTORMS WERE MOVING INTO SOUTHERN TOOLE AND SOUTHERN LIBERTY. THUNDERSTORMS WERE MOVING TO THE NORTH ABOUT 20 MILES AN HOUR. SOME OF THESE THUNDERSTORMS WILL HAVE HEAVY RAIN AS WELL AS HAIL UP TO PEA SIZE AND GUSTY WINDS UP TO 40 MILES AN HOUR. OVER AN INCH OF RAIN WAS REPORTED NORTH OF THE KNEES IN EXTREME NORTHWEST CHOUTEAU COUNTY BETWEEN 5 AND 6PM MDT. CASCADE COUNTY...INCLUDING THE CITY OF GREAT FALLS...IS NO LONGER UNDER A SEVERE THUNDERSTORM WATCH. THUNDERSTORMS HAVE MOVED NORTH OF THE COUNTY. BLANK
Nearby
Flash Flood Warnings in Montana, 1991Every flash flood warning in 1991
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.