A thunderstorm over the northern portion of the Lake of the Woods produced microburst winds.
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The episode as NWS FGF wrote it up.
A thunderstorm over the northern portion of the Lake of the Woods produced microburst winds.
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 29, 8:26 PM CST, 8 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAND FORKS ND 926 PM CDT FRI MAY 29 2009 .DISCUSSION... MAIN FORECAST CHALLENGE IS PRECIPITATION. WHEN LOOKING AT THE LATEST SURFACE ANALYSIS...A WARM FRONT AND TROF EXTENDS THROUGH THE AREA ALONG A ROX TO GFK TO JMS LINE...WITH A COLD FRONT ALONG A HCO-LANGDON-MOT LINE. WHEN COMPARING THE MODELS...THE MODELS ARE SIMILAR...SO ENDED UP USING A MODEL BLEND FOR THE FORECAST UPDATE. WITH THE BEST INSTABILITY QUICKLY MOVING E OF THE AREA THIS EVENING...WE STILL HAVE SOME SHRA WITH ISOLD TSRA IN PARTS OF SE ND AND WC MN...BUT THE POTENTIAL FOR ANY SVR FOR HAIL HAS DEFINITELY DISSIPATED. THE BIGGEST CONCERN FOR THE CONVECTION THAT REMAINS IS IF IT WILL BE ABLE TO CONTINUE TO MIX DOWN STRONGER WINDS FROM ALOFT. THERE HAVE BEEN SEVERAL REPORTS THIS EVENING OF AROUND 45 MPH WINDS OCCURRING FROM THESE SHRA. WITH THE POTENTIAL OF CONVECTION LINGERING UNTIL MIDNIGHT...STILL EXPECT THE STRONGER CELLS (35 TO 40 DBZ) TO HAVE THE POTENTIAL TO CREATE WIND GUSTS TO AROUND 45 MPH. SINCE THESE OCCURRENCES REMAIN ISOLATED...WILL CONTINUE TO COVER THE STRONGER SHRA WITH NOWCASTS AND NOT ADD ANY WORDING TO THE GRIDS OR ZONES FOR THIS. OTHER PARTS OF THE FORECAST THAT NEEDED SOME MINOR ADJUSTMENTS WERE TEMPS...SINCE HAVE BEEN HOLDING UP IN E ND MORE THAN PREVIOUSLY EXPECTED AND ALTHOUGH THE WINDS ARE DIMINISHING...THEY HAVE NOT DROPPED AS QUICKLY AS PREVIOUSLY THOUGHT EITHER. REST OF FORECAST ON TARGET...WITH MINIMAL CHANGES NEEDED. && .AVIATION... SC DECK WILL CONTINUE TO DISSIPATE THIS EVENING AS SCT SHRA AND ISOLD TSRA MOVE S AND E AS WELL. RESIDUAL AC AND CI EXPECTED TO MOVE OUT OF THE AREA BEFORE 12Z. NO VSBY REDUCTIONS ANTICIPATED. WINDS TO DIE DOWN TO AROUND 10 KTS BEFORE 06Z THIS EVENING AND TURN FROM W TO NW TO MORE NW TO N BY 18Z SAT. && .PREV DISCUSSION... /ISSUED 304 PM CDT FRI MAY 29 2009/ SHORT TERM (FRI-MON)... MAIN FORECAST CHALLENGE WILL BE ONSET OF CONVECTION FOR THIS AFTERNOON AND EVENING. SFC ANALYSIS SHOWS THE WARM FRONT PUSHING INTO THE E ZONES AS REFLECTED BY TEMPS JUMPING INTO THE MID 70S IN MOST AREAS. DESPITE LIMITED MOISTURE WITH DEWPOINTS REMAINING IN THE UPPER 30S/LOWER 40S...LOW LEVEL LAPSE RATES ARE PUSHING 9C/KM AND MID LEVEL LAPSE RATES ARE AROUND 7.5C/KM. THE 0-6 KM SHEAR VECTOR VARIES FROM 50-70 KTS SO POTENTIAL EXISTS FOR ISOLATED SUPER CELL DEVELOPMENT. CAPE VALUES EXPECTED TO BE AROUND 1000 J/KG WITH NO CAP TO INHIBIT CONVECTION. WITH DOWNDRAFT CAPES IN THE 700-900 J/KG RANGE...EXPECT GENERATION OF STRONG OUTFLOWS FROM THE STORMS. THEREFORE...THE GREATEST THREAT FOR SEVERE WILL BE WINDS AND HAIL. FOR THE WEEKEND...ONCE THE TRAILING COLD FRONT PUSHES THRU...WILL SEE INCREASING STABILITY AND COOLER TEMPERATURES WITH SFC WINDS BECOMING MORE NWRLY. HOWEVER...WITH NW FLOW ALOFT...EXPECT TO SEE ANOTHER WAVE DEVELOP AND MORE CHANCES FOR -SHRA/TRW ON SUN. LONG TERM (TUE-FRI)... THE EXTENDED MODELS ARE IN PRETTY GOOD AGREEMENT OVERALL...WITH THE CONTINUATION OF TEMPS BELOW NORMAL THROUGH THE PERIOD. THE BEST CHANCE FOR SHOWERS AND A FEW STORMS WOULD BE ON THU-THU NIGHT AHEAD OF A FRONT...AND WILL MENTION. OTHERWISE...WILL KEEP THE REST OF THE EXTENDED DRY FOR NOW WITH HARD TO TIME SHORTWAVES IN NW FLOW ALOFT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && NG
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND FORKS ND 1141 AM CDT FRI MAY 29 2009 MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024- 026>030-038-039-049-052>054-301645- 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 COUNTY-EDDY-NELSON- GRAND FORKS-GRIGGS-STEELE-TRAILL-BARNES-CASS-RANSOM-SARGENT- RICHLAND-WESTERN WALSH COUNTY- 1141 AM CDT FRI MAY 29 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN NORTH DAKOTA...WEST CENTRAL AND NORTHWEST MINNESOTA. .DAY ONE...THIS AFTERNOON AND TONIGHT THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS...CONTAINING LARGE HAIL AND DAMAGING WINDS...FOR ALL OF EASTERN NORTH DAKOTA...NORTHWEST AND WEST CENTRAL MINNESOTA THIS AFTERNOON INTO THIS EVENING. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AFTER 2 PM IN NORTHEAST NORTH DAKOTA INTO NORTHWEST MINNESOTA...THE STORMS MAY BECOME SEVERE BETWEEN 3 PM AND 10 PM AHEAD OF A COLD FRONT. STORMS WILL DIMINISH AFTER SUNSET ONCE DRIER AIR BUILDS IN FROM THE NORTHWEST. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THUNDERSTORMS ARE POSSIBLE LATE SATURDAY NIGHT THROUGH SUNDAY. A FEW STORMS MAY BECOME SEVERE SUNDAY AFTERNOON IN SOUTHEAST NORTH DAKOTA INTO WEST CENTRAL MINNESOTA AHEAD OF ANOTHER COLD FRONT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE REQUIRED THIS AFTERNOON AND EVENING. DK
The national radar mosaic for the moment the first event began.
1 thunderstorm wind. Local standard time, as filed.
A MN DNR official reported an apparent dry microburst between Oak Island and Flag Island on the Lake of the Woods. winds gusted to 59 mph at the Flag Island ASOS (FGN).
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2009Every state in 2009This day in weather historyWarnings in Minnesota, May 2009
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: 175334.