Alert archive / Minnesota / Severe Thunderstorm Warnings in 1987
Severe Thunderstorm Warning 37, NWS Grand Forks, ND
NWS Grand Forks, ND issued this severe thunderstorm warning at Jul 21, 1987, 7:02 PM CDT for Clay County, Norman County, Minnesota; Cass County, Traill County, North Dakota. It was in force for 58 min. 4 reports came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- Jul 21, 1987, 7:02 PM CDT (00:02 UTC)
- Expired
- Jul 21, 1987, 8:00 PM CDT
- In force
- 58 min
- Issued by
- NWS Grand Forks, ND
- Area
- Whole counties
Counties Clay County, MN, Norman County, MN, Cass County, ND, Traill County, ND
The radar
The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 21, 7:30 PM CDT | Hail 2.5 | Traill, ND | |
| Jul 21, 7:39 PM CDT | Thunderstorm Wind 60 | Cass, ND | |
| Jul 21, 7:45 PM CDT | Tornado F0 | Clay, MN | |
| Jul 21, 8:00 PM CDT | Thunderstorm Wind 0 | Clay, MN |
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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.
The nearest sounding before it
Aberdeen, SD (KHON), launched 00:00Z, 0.0 hours before the alert went out and 278 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
- 3245 J/kg
- Mixed-layer CIN
- -101 J/kg
- Mixed-layer LCL
- 1717 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 129 m²/s²
- 0-3 km storm-relative helicity
- 309 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 9.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KFAR 220002 SVRFAR NDC017-097-MNC027-107-220100- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE FARGO ND 702 PM CDT TUE JUL 21 1987 THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 800 PM CDT FOR PEOPLE IN THE FOLLOWING COUNTIES OF EAST CENTRAL NORTH DAKOTA...CASS AND EXTREME SOUTHERN TRAILL NORTHWEST MINNESOTA...CLAY AND NORMAN TO INCLUDE THE TOWNS AND CITIES OF CASSLETON...HARWOOD...HAWLEY... GEORGETOWN...MAPLETON AND THE FARGO/MOORHEAD AREA. AT 645 PM CDT RADAR INDICATED SEVERE THUNDERSTORMS 25 MILES NORTH AND 35 MILES NORTHWEST OF FARGO NORTH DAKOTA MOVING TOWARD THE EAST AT 40 MILES AN HOUR. REMEMBER...SEVERE THUNDERSTORMS CAN PRODUCE DAMAGING WINDS IN EXCESS OF 58 MPH AND/OR HAIL 3/4 INCH OR LARGER...DEADLY LIGHTNING... AND HEAVY RAINS THAT CAN QUICKLY FLOOD A LOW LYING AREA. REMEMBER...SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE A TORNADO WITH LITTLE OR NO ADVANCE WARNING SO BE ON THE LOOKOUT. IF THREATENING WEATHER APPROACHES...YOU SHOULD GO TO A PLACE OF SAFETY IMMEDIATELY. REPORT ALL SEVERE WEATHER TO YOUR LOCAL LAW ENFORCEMENT AGENCY AFTER THE STORM PASSES. VOELKER /
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.
In the hours before
Special weather statement, Jul 21, 3:38 PM CDT, 3 hours 24 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY NATIONAL WEATHER SERVICE FARGO ND 335 PM CDT TUE JUL 21 1987 ...A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 9 PM CDT THIS TUESDAY EVENING FOR A LARGE PART OF NORTH DAKOTA AND A PART OF NORTHWEST MINNESOTA... AT 325 PM CDT...A PAIR OF INTENSE THUNDERSTORMS WERE LOCATED 30 MILES AND 50 MILES NORTHWEST OF JAMESTOWN NORTH DAKOTA OR NEAR THE TOWNS OF NEW ROCKFORD AND CARRINGTON. THESE THUNDERSTORMS WERE MOVING TO THE EAST AT 40 MILES AN HOUR AND WILL MOVE INTO GRIGGS AND SOUTHERN NELSON COUNTIES BY 425 PM CDT. PERSONS LIVING IN THESE AREAS...ESPECIALLY THE TOWNS OF COOPERSTOWN...HANNAFORD...AND DAZEY SHOULD BE ALERT FOR RAPIDLY CHANGING WEATHER CONDITIONS AND SHOULD BE PREPARED TO SEEK SHELTER IF NECESSARY. ALSO AT 325 PM CDT...SCATTERED SHOWERS AND THUNDERSTORMS...SOME WITH HEAVY RAIN...WERE LOCATED OVER NORTHEAST AND CENTRAL NORTH DAKOTA. THESE SHOWERS AND THUNDERSTORMS W(ERE ALSO MOVING TO THE EAST AT 40 MILES AN HOUR. MB
The office that day
Everything else NWS Grand Forks, ND issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 7:58 PM CDT | Tornado Warning | FGF | Becker, Clay, Mahnomen, Otter Tail | 62 min |
| Jul 21, 8:38 PM CDT | Severe Thunderstorm Warning | FGF | Norman, Polk | 62 min |
| Jul 21, 8:45 PM CDT | Severe Thunderstorm Warning | FGF | Beltrami, Clearwater | 60 min |
| Jul 21, 9:00 PM CDT | Severe Thunderstorm Warning | FGF | Becker, Hubbard, Wadena | 60 min |
| Jul 21, 11:26 PM CDT | Severe Thunderstorm Warning | FGF | Norman | 49 min |
| Jul 22, 12:15 AM CDT | Severe Thunderstorm Warning | FGF | Mahnomen, Norman | 50 min |
| Jul 22, 1:21 AM CDT | Severe Thunderstorm Warning | FGF | Becker, Mahnomen, Norman | 54 min |
| Jul 22, 1:30 AM CDT | Severe Thunderstorm Warning | FGF | Clearwater | 75 min |
| Jul 22, 1:53 AM CDT | Severe Thunderstorm Warning | FGF | Norman | 52 min |
| Jul 22, 1:53 AM CDT | Severe Thunderstorm Warning | FGF | Clay | 52 min |
| Jul 21, 7:14 PM CDT | Tornado Warning | FGF | Nelson | 61 min |
| Jul 21, 7:41 PM CDT | Severe Thunderstorm Warning | FGF | Grand Forks, Steele | 49 min |
| Jul 21, 7:41 PM CDT | Severe Thunderstorm Warning | FGF | Griggs | 49 min |
| Jul 21, 8:49 PM CDT | Severe Thunderstorm Warning | FGF | Nelson | 56 min |
| Jul 21, 9:50 PM CDT | Severe Thunderstorm Warning | FGF | Griggs, Nelson, Steele | 55 min |
| Jul 21, 9:50 PM CDT | Severe Thunderstorm Warning | FGF | Grand Forks, Traill | 55 min |
| Jul 21, 10:44 PM CDT | Severe Thunderstorm Warning | FGF | Griggs, Steele, Traill | 61 min |
| Jul 21, 11:53 PM CDT | Severe Thunderstorm Warning | FGF | Steele, Traill | 52 min |
| Jul 21, 11:53 PM CDT | Severe Thunderstorm Warning | FGF | Griggs | 52 min |
| Jul 22, 12:47 AM CDT | Severe Thunderstorm Warning | FGF | Steele, Traill | 58 min |
Nearby
Severe Thunderstorm Warnings in Minnesota, 1987Severe Thunderstorm Warnings in North Dakota, 1987Every severe thunderstorm warning in 1987
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.