A frontal boundary extended along a line from Langdon to Lisbon late in the afternoon of the 27th. With afternoon heating, strong instability developed across eastern North Dakota.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS FGF wrote it up.
A frontal boundary extended along a line from Langdon to Lisbon late in the afternoon of the 27th. With afternoon heating, strong instability developed across eastern North Dakota. One thunderstorm cell produced a tornado that touched down twice.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Grand Forks, ND wrote its last area forecast discussion before the first event at May 27, 1:30 PM CST, 2 hours 20 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 230 PM CDT FRI MAY 27 2011 .SHORT TERM... /TONIGHT THROUGH MON/ CURRENT METARS INDICATING CENTER OF SFC LOW JUST EAST OF BROADVIEW...SASKATCHEWAN ALONG THE SASK/MANITOBA BORDER...WITH A SFC BOUNDARY EXTENDED SOUTHEASTWARD THROUGH THE DEVILS LAKE BASIN AND INTO RANSOM/SARGENT COUNTY AREA. AHEAD OF THE BOUNDARY...H850 JET AND H850 WAA RESULTING IN NUMEROUS SHOWERS EXTENDING ALONG THE RED RIVER VALLEY AND EASTWARD...ACROSS MAJORITY OF EASTERN CWA. WEST OF THE BOUNDARY...MOST OF CENTRAL AND WRN NORTH DAKOTA SAW AMPLE SUNSHINE TODAY AND ASSOCIATED HEATING IS RESULTING IN WIDESPREAD CU ACROSS THE AREA. BEGINNING TO SEE SOME ENHANCED CU IN THE JAMES VALLEY. SO KEY FORECAST CHALLENGES FOR THIS EVENING AND TONIGHT WILL BE EASTWARD EXTEND OF ANY TSTMS WHICH VERY WELL COULD POP UP...AND OVERNIGHT LOWS. IN GENERAL USED A FCST BLEND...TRANSITIONING TO MORE OF A GFS-FLAVOR BY EARLY NEXT WEEK. TONIGHT AND TOMORROW... SFC BOUNDARY WILL CONTINUE TO PUSH EASTWARD WITH RAIN SHOWERS AHEAD OF BOUNDARY. LATEST NAM AND RUC BOTH SHOWING NEGATIVE SHOWALTERS ACROSS CENTRAL NORTH DAKOTA...WITH WEAK SFC BASED CAPES AND MOST UNSTABLE CAPES AROUND 1000 J/KG. THUS THINK THERE IS A DECENT CHANCE OF SEEING SOME THUNDERSTORMS...MAINLY WEST OF THE RED RIVER VALLEY AND SFC BOUNDARY/CLEARING LINE. IN THE IMMEDIATE NEAR TERM CELLS COULD MOVE INTO VALLEY CITY AREA BY 00Z. MAIN BAND OF PRECIP SHOULD MOVE EAST OF CWA BY AROUND 12Z SATURDAY...THEN THE MODELS HAVE SOME DIFFERENCES IN POSITION OF SFC LOW WITH THE GFS BEING THE FURTHEST SOUTH. THINK BEST CHANCE OF SHOWERS TOMORROW WILL BE ACROSS THE NORTH...ESP THE DVL LAKE AREA...AS THE LOW TRACKS ALONG THE INTL BORDER. MORE SUNSHINE ACROSS THE SOUTH EXPECTED...WHICH WILL BRING A CHANCE FOR SOME ISOLATED TSTMS ACROSS SOUTHERN ZONES TOMORROW AFTERNOON. SUNDAY...HAVE REMOVED POPS FOR SUNDAY AS SYSTEM PULLS OUT OF THE AREA...WITH SOME SUNSHINE AND HIGHS IN THE MID 60S. WILL DEFINITELY BE THE BEST DAY OF THE HOLIDAY WEEKEND FOR OUTDOOR ACTIVITIES. CLOUDS WILL BEGIN TO MOVE IN FROM THE SOUTHWEST SUN EVENING AHEAD OF THE NEXT SYSTEM. SUN NIGHT INTO MEMORIALS DAY...FRONTAL BOUNDARY WILL PUSH NORTH INTO NORTH DAKOTA SUN NIGHT...BRINGING INCREASING SKY COVER AND RAINFALL TO WESTERN ZONES BY MON MORNING. GIVEN DECENT MOISTURE TRANSPORT...EXPECT RAIN SHOWERS TO EXPAND ACROSS CWA DURING THE DAY ON MONDAY. BY NOONTIME MONDAY...INCREASED INSTABILITY ACROSS THE SOUTHERN ZONES ARE EXPECTED TO BRING TSTM DEVELOPMENT TO THE SOUTH AND SOUTHEAST. SHOWALTERS EXPECTED TO DROP TO AROUND NEG 6 BY MID MONDAY AFTN. SPC NOW SHOWING A SEVERE THREAT FOR THE SOUTHERN VALLEY FOR MON EVENING...WHICH WILL BE ON THE NOSE OF A 40KT LLJ WITH MODEST UPPER LEVEL DIVERGENCE. POTENTIAL IS THERE FOR FIRST SIGNIFICANT SEVERE OUTBREAK OF THE SEASON...MAINLY FROM THE SOUTHERN VALLEY AND SOUTHEASTERN ZONES. .LONG TERM... /MON NIGHT THROUGH FRI/ SFC LOW WILL EXIT NORTH DAKOTA INTO MANITOBA MONDAY NIGHT WITH LINGERING CONVECTION EXITING NORTHWEST MINNESOTA NR 06Z. DRY SLOT WILL WORK IN BEHIND SYSTEM...WITH WRAPAROUND SHOWERS A POSSIBILITY ON TUESDAY IN COLD ADVECTION. IT LOOKS WINDY TUESDAY AS WELL. HIGH PRESSURE WILL DROP SOUTH INTO ERN ND/NRN MN FOR WED-THU...ALTHOUGH AN UPPER LEVEL DISTURBANCE IS PROGGED TO MOVE THRU CNTRL PLAINS THURSDAY AND MAY BRUSH FAR SRN FCST AREA WITH LOW THREAT FOR PRECIP THURSDAY. WILL KEEP HPC LOW POPS GOING FRIDAY AS WARM ADVECTION OUT AHEAD OF NEXT IMPULSE OUT OF THE WEST COAST TROUGH MOVES INTO THE HIGH PLAINS WITH BEST CHC OF PRECIP NEXT SATURDAY (DAY 8 PERIOD). && .AVIATION... RAIN SHOWER BAND AND CLOUDS WITH IT INITIALLY VFR CIGS THEN FOLLOWED BY A PERIOD OF MVFR CIGS/VSBYS WITH HEAVIER RAIN. AS SYSTEM MOVES EAST...IT WILL REPLACED BY MOSTLY VFR CIGS/VSBY FOR THE REST OF THE AFTN/NIGHT. && .HYDROLOGY... DRAYTON CANCELLED THIS MORNING AND NOW ONLY FARGO REMAINS ABOVE FLOOD STAGE. ITS SLOW RECESSION WILL CONTINUE AS RAIN THROUGH SUNDAY WILL HAVE NEGLIGIBLE IMPACTS TO THE RIVER SYSTEM. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && SPEICHER/RIDDLE/JK
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND FORKS ND 351 PM CDT FRI MAY 27 2011 MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-026- 027-030-054-282100- WEST POLK-NORMAN-CLAY-KITTSON-ROSEAU-LAKE OF THE WOODS- WEST MARSHALL-EAST MARSHALL-NORTH BELTRAMI-PENNINGTON-RED LAKE- EAST POLK-NORTH CLEARWATER-SOUTH BELTRAMI-MAHNOMEN- SOUTH CLEARWATER-HUBBARD-WEST BECKER-EAST BECKER-WILKIN- WEST OTTER TAIL-EAST OTTER TAIL-WADENA-GRANT-TOWNER-CAVALIER- PEMBINA-BENSON-RAMSEY-EASTERN WALSH-EDDY-NELSON-GRAND FORKS- TRAILL-WESTERN WALSH- 351 PM CDT FRI MAY 27 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN NORTH DAKOTA...WEST CENTRAL AND NORTHWEST MINNESOTA. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED SHOWERS WILL GRADUALLY END FROM THE WEST LATE AFTERNOON AND EARLY EVENING OVER NORTHWEST AND WEST CENTRAL MINNESOTA. ISOLATED SHOWERS WILL OCCUR BEHIND THE MAIN RAIN BAND THROUGH EARLY EVENING OVER THE NORTHERN RED RIVER VALLEY. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE SATURDAY. A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL OCCUR MONDAY AND MONDAY EVENING. A FEW STORMS MAY BE STRONG OR SEVERE IN WEST CENTRAL MINNESOTA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED. NDZ028-029-038-039-049-052-053-282100- GRIGGS-STEELE-BARNES-CASS-RANSOM-SARGENT-RICHLAND- 351 PM CDT FRI MAY 27 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN NORTH DAKOTA...WEST CENTRAL AND NORTHWEST MINNESOTA. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED THUNDERSTORMS WILL MOVE INTO SOUTHEAST NORTH DAKOTA LATE THIS AFTERNOON AND EARLY EVENING MAINLY IMPACTING FROM VALLEY CITY TO LISBON TO FORMAN. SMALL HAIL IS POSSIBLE. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE SATURDAY. A BETTER CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WILL OCCUR ON MONDAY AND MONDAY EVENING. SOME OF THESE STORMS MONDAY LATE AFTERNOON OR EARLY EVENING COULD BE STRONG TO SEVERE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED. DTR
The Fargo/Grand Forks radar (KMVX), 77 km away, was scanning. The volume nearest the first event began at 21:49 UTC.
2 tornado. Local standard time, as filed.
Law enforcement observed this tornado as it tracked intermittently along a roughly 4 mile track. The wall cloud structure and storm continued northeastward and produced at least one additional brief tornado. Peak winds were estimated at 75 mph.
A persistent wall cloud and funnel tracked northeast from the Baldhill Dam area and produced multiple brief touchdowns along its path. Peak winds were estimated at 70 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in North Dakota in 2011Every state in 2011This day in weather historyThe tornado archive for North Dakota, 2011Warnings in North Dakota, May 2011
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 299004, 317919.