A very unusual warm, windy and dry air mass moved northward across the upper midwest on May 20. During the early morning hours of May 20th, sustained winds of 30 to 40 mph occurred across west central Minnesota.
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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 MPX wrote it up.
A very unusual warm, windy and dry air mass moved northward across the upper midwest on May 20. During the early morning hours of May 20th, sustained winds of 30 to 40 mph occurred across west central Minnesota. These winds continued through the day and expanded eastward across eastern Minnesota by the lunch hour. During the afternoon, peak wind gusts of 45 to 55 mph occurred across a large area of southern and east central Minnesota...as well as portions of west central Minnesota. These winds in combination of the recent dry soil conditions across southern Minnesota, led to areas of blowing dust which was the top soil of many farms across southern Minnesota. Visibilities were reduced as low as two miles in the blowing dust which was transported northeast across most of east central Minnesota during the afternoon. During the time of peak wind gusts, there were several reports of large trees blown down and minor damage to roofs. The following are some of the highest wind speeds recorded on Wednesday.
Redwood Falls. 55 mph.|St. James. 54 mph.|Fairmont. 54 mph.|Waseca. 53 mph. |Owatonna. 51 mph.|Tracy. 51 mph. |Twin Cities International Airport. 50 mph.|Eden Prairie. 50 mph.
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 Twin Cities, MN wrote its last area forecast discussion before the first event at May 20, 11:38 AM CST, 1 hour 7 minutes earlier.
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1238 PM CDT WED MAY 20 2009
.UPDATE...
CORRECTION TO TAF DISCUSSION BELOW.
&&
.DISCUSSION...
EXPANDED WIND ADVY TO INCLUDE ALL OF CWA WITH SOME STATION IN NW
CWA MEETING CRITERIA NOW. HOWEVER...WINDS WILL BEGIN TO DECREASE
DURING THE AFTN IN NW AREAS AS LOW LEVEL WIND MAX CONTINUES TO
TRANSLATE EAST. THIS TREND WAS ADDRESSED IN NPW.
&&
.AVIATION.../18Z TAF ISSUANCE/
THE MAIN FORECAST CONCERN IS THE STRONG WINDS FOR THE REST OF THE
AFTERNOON AND TIMING OF THE FRONT. ALSO VSBYS HAVE BEEN REDUCED INTO
THE MVFR CATEGORY DUE TO BLOWING DUST. MAIN BAND OF LOW LEVEL WINDS
WILL BE ACROSS THE EASTERN HALF OF THE FORECAST AREA. EXPECT WIND
DIRECTIONS OF 190-220 IN THIS MAIN BAND...WITH A FEW GUSTS TO 40-45
KNOTS. SUSTAINED SPEEDS AVERAGING 25K...WHICH WILL ALSO LOWER VSBYS
TO 3SM AT KSTC AND KRWF. KRNH AND KMSP...ALSO IN THE MAIN BAND OF
WINDS WILL BE LESS PRONE TO VSBY RESTRICTION...DUE TO GREATER
DISTANCE FROM SOURCES OF DIRT AND DUST. VERY DRY AIRMASS AHEAD OF
THE COLD FRONT...THUS DO NOT EXPECT MUCH IF ANY CONVECTIVE
DEVELOPMENT. THE BEST MOISTURE INCREASE AND SUBSEQUENT ADVECTION OF
INSTABILITY WILL INITIALLY BE INTO NORTHERN MN. THEN BETTER
CONVERGENCE WILL DEVELOP BACK TO THE SOUTHWEST OVER SOUTHWEST MN
INTO SOUTH CENTRAL SD. WILL INCLUDE A CHANCE OF SHOWERS JUST BEHIND
THE FRONT AT THE MN TAF SITES...ALONG WITH A CB...BUT WILL HOLD OFF
ON THUNDER AT THIS TIME. OTHERWISE...VFR CONDITIONS WILL
PREVAIL...WITH CIGS AS LOW AT 050-060. SOME CHANCE OF A LITTLE MORE
WIDESPREAD SHOWER ACTIVITY OVER SOUTHERN MN UNDER THE UPPER LEVEL
JET AND JUST NORTH OF THE FRONT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ANOKA-BENTON-BLUE
EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-DOUGLAS-
FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI-KANABEC-
KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE
LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE-
SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD-
WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE.
RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR ANOKA-BENTON-
CHISAGO-ISANTI-KANABEC-MILLE LACS-MORRISON-SHERBURNE.
WI...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BARRON-CHIPPEWA-
DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
RAH/JPRHAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 936 AM CDT WED MAY 20 2009 MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028- 211100- DOUGLAS-TODD-MORRISON-MILLE LACS-KANABEC-STEVENS-POPE-STEARNS- BENTON-SHERBURNE-ISANTI-CHISAGO-LAC QUI PARLE-SWIFT-CHIPPEWA- KANDIYOHI-MEEKER-WRIGHT-HENNEPIN-ANOKA-RAMSEY-WASHINGTON- YELLOW MEDICINE-RENVILLE-MCLEOD-SIBLEY-CARVER-SCOTT-DAKOTA- REDWOOD-BROWN-NICOLLET-LE SUEUR-RICE-GOODHUE-WATONWAN-BLUE EARTH- WASECA-STEELE-MARTIN-FARIBAULT-FREEBORN-POLK-BARRON-RUSK- ST. CROIX-PIERCE-DUNN-PEPIN-EAU CLAIRE- 936 AM CDT WED MAY 20 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND SOUTHERN MINNESOTA...AND WEST CENTRAL WISCONSIN. .DAY ONE...TODAY AND TONIGHT STRONG SOUTHERLY WINDS AT 25 TO 35 MPH WILL OCCUR TODAY ACROSS ALL OF CENTRAL AND SOUTH CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN. WIND GUSTS TO 50 MPH ARE ALSO POSSIBLE. WARM TEMPERATURES COMBINED WITH THE STRONG SOUTHERLY WINDS AND LOW RELATIVE HUMIDITY...WILL CREATE DANGEROUS WILDFIRE CONDITIONS ACROSS THE ENTIRE AREA TODAY. HOWEVER...DRIER FUEL CONDITIONS COMBINED WITH THE STRONG WINDS AND LOW HUMIDITY...WOULD PLACE EAST CENTRAL MINNESOTA IN THE GREATEST RISK. A COLD FRONT WILL MOVE SLOWLY SOUTHEAST ACROSS THE REGION TONIGHT. A FEW THUNDERSTORMS WILL ACCOMPANY THE FRONT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THERE IS A CHANCE FOR THUNDERSTORMS ACROSS MUCH OF THE OUTLOOK AREA SUNDAY THROUGH TUESDAY. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1212 PM CDT WED MAY 20 2009 MNZ043>045-049>054-056>070-073>078-082>085-091>093-202200- MORRISON-MILLE LACS-KANABEC-STEARNS-BENTON-SHERBURNE-ISANTI- CHISAGO-LAC QUI PARLE-CHIPPEWA-KANDIYOHI-MEEKER-WRIGHT-HENNEPIN- ANOKA-RAMSEY-WASHINGTON-YELLOW MEDICINE-RENVILLE-MCLEOD-SIBLEY- CARVER-SCOTT-DAKOTA-REDWOOD-BROWN-NICOLLET-LE SUEUR-RICE-GOODHUE- WATONWAN-BLUE EARTH-WASECA-STEELE-MARTIN-FARIBAULT-FREEBORN- INCLUDING THE CITIES OF...LITTLE FALLS...PRINCETON...MORA... ST. CLOUD...FOLEY...ELK RIVER...CAMBRIDGE...CENTER CITY... MADISON...MONTEVIDEO...WILLMAR...LITCHFIELD...MONTICELLO... MINNEAPOLIS...BLAINE...ST. PAUL...STILLWATER...GRANITE FALLS... OLIVIA...HUTCHINSON...GAYLORD...CHASKA...SHAKOPEE...BURNSVILLE... REDWOOD FALLS...NEW ULM...ST. PETER...LE SUEUR...FARIBAULT... RED WING...ST. JAMES...MANKATO...WASECA...OWATONNA...FAIRMONT... BLUE EARTH...ALBERT LEA 1212 PM CDT WED MAY 20 2009 ...BLOWING DUST OVER SCATTERED SECTIONS OF SOUTH CENTRAL AND CENTRAL MINNESOTA... THE STRONG SOUTH WINDS OF 30 TO 35 MPH WITH OCCASIONAL GUSTS TO AROUND 50 MPH...HAVE CAUSED DIRT AND DUST TO BE PICKED UP FROM FARM FIELDS AND OTHER OPEN AREAS. THE BLOWING DIRT AND DUST HAS ACTUALLY LIMITED VISIBILITY TO AS LOW AS 2 MILES IN SPOTS. EXPECT TO ENCOUNTER THIS BLOWING DUST FOR THE REMAINDER OF THE AFTERNOON...ESPECIALLY IN THE OPEN AREAS OF CENTRAL AND SOUTH CENTRAL MINNESOTA. IN ADDITION...THE STRONG WINDS COULD ALSO TAKE TREE BRANCHES DOWN. THE STRONG WINDS ARE OUT AHEAD OF AN ADVANCING COLD FRONT...WHICH WILL ENTER WESTERN MINNESOTA LATE THIS AFTERNOON.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
111 PM CDT WED MAY 20 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0109 PM NON-TSTM WND DMG STILLWATER 45.06N 92.82W
05/20/2009 WASHINGTON MN PUBLIC
TREE DOWN
&&
JPRThe national radar mosaic for the moment the first event began.
5 strong wind. Local standard time, as filed.
A large 18 diameter tree fell down in the Prior Lake area.
Two areas in St. James, Minnesota had minor wind damage as strong winds develop during the afternoon of May 20th. The residence of Mr. Hillis Peterson had one of their large Basswood trees fall. His home was on 11th Ave South in St. James. In addition, the business of Performance Plating, which is also on 11th Ave, had a section of their roof torn loose by the high winds.
Strong winds of 50 to 55 mph caused an 18-wheeler to flip over near Cannon Falls and caused numerous trees to fall between Kenyon and Cannon Falls.
Several reports of blown down telephone poles, utility poles and large trees occurred across portions of Hennepin County. Xcel crews reported 5900 customers without power during the afternoon. The city of Minnetonka reported live electrical lines that snaked across a parking lot and over parked cars outside Weber's Westdale Flowers and Home and Garden center, new Horizon Daycare, and an office building on 15300 block of Minnetonka Boulevard.
The county highway department cleared debris from roadways and fixed stop signs that were blown over during the afternoon in Redwood Falls, as sustainted winds of 50 to 55 developed.
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: 162046, 164359, 164360, 164361, 164362.