An early morning outflow boundary that was associated with thunderstorms that moved across western, and into eastern Minnesota, stalled across south central and east central Minnesota around noon. This boundary aided in the initiation of thunderstorms across south central Minnesota during the early afternoon hours of July 7th.
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The episode as NWS MPX wrote it up.
An early morning outflow boundary that was associated with thunderstorms that moved across western, and into eastern Minnesota, stalled across south central and east central Minnesota around noon. This boundary aided in the initiation of thunderstorms across south central Minnesota during the early afternoon hours of July 7th. Due to weak winds aloft and high moisture content of the atmosphere, the storms moved very slowly to the northeast, with some training in portions of south central and east central Minnesota during the afternoon. An observer in south central Minnesota recorded 4.10 inches of rainfall in less than two hours near the town of Granada. Due to the excessive rainfall, basement flooding was reported in the town of Granada. Several other locations across south central Minnesota had rainfall amounts of two to three inches. Around the Twin Cities, a few thunderstorms produced locally two to three inches near Bloomington which causes some minor street flooding.
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 Jul 7, 1:03 PM CST, 1 hour 27 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 203 PM CDT WED JUL 7 2010 .DISCUSSION... PRIMARY FORECAST CONCERNS ARE CHANCES FOR CONVECTION THIS AFTERNOON INTO TONIGHT WITH BOUNDARY LYING OVER THE AREA AS UPPER TROUGH FINALLY WORKS TO PUSH IT EAST OF US TONIGHT INTO THURSDAY. PREVIOUS DISCUSSION INCLUDED BELOW DETAILS EXPECTATIONS WITH THINGS THIS AFTERNOON AND EVENING QUITE WELL... AND DO NOT INTEND TO DEVIATE MUCH FROM THE UPDATES MADE TO THE FORECAST EARLIER THIS AFTERNOON. ONCE THESE CONCERNS ARE OUT OF OUR WAY... ATTENTION TURNS TOWARD NEXT SYSTEM AND CHANCE FOR SHRA/TSRA... WHICH WILL IMPACT THE AREA FROM SATURDAY NIGHT INTO MONDAY. OVERALL... SHORT RANGE MODEL GUIDANCE IS IN DECENT AGREEMENT OVER THE NEXT FEW DAYS AND WILL ESSENTIALLY FOLLOW A BLEND OF THE NAM AND GFS SOLUTIONS TOGETHER WITH CONTINUITY FROM THE PREVIOUS FORECAST. THE MAIN POINT OF DISCONNECT IN THE GUIDANCE IS WITH A BIT OF A BACKDOOR REINFORCING SHOT OF COOL AIR PROGGED TO SAG INTO THE AREA FRIDAY AFTERNOON AND EVENING... WITH THE NAM MANAGING TO GENERATE A BAND OF PCPN WHILE THE GFS AND ECMWF KEEP THINGS DRY. GIVEN MINIMAL RETURN FLOW AHEAD OF THIS FEATURE... CHANCES FOR PCPN LOOK MINIMAL... SO WILL KEEP THINGS DRY AT THIS POINT. FOR THE LONGER TERM... THE GFS AND ECMWF AND THEIR RESPECTIVE ENSEMBLES ARE IN FAIRLY GOOD AGREEMENT INTO THE FIRST PART OF THE WEEK... WITH DIFFERENCES IN SOLUTIONS BECOME MORE PRONOUNCED BY MIDWEEK AS THE NORTHWEST UPPER FLOW IS PROGGED TO BREAK DOWN IN SOME FASHION AS UPPER TROUGHING TRIES TO RE-ESTABLISH ITSELF OVER WESTERN NORTH AMERICA. A MIDDLE OF THE ROAD APPROACH UTILIZING HPC GUIDANCE AND A BLEND OF THE GFS AND ECMWF SOLUTIONS IS THE SAFEST ROUTE AT THIS POINT GIVEN THE UNCERTAINTY... SO WILL USE THAT APPROACH DURING THE LATTER HALF OF THE FORECAST. SHRA/TSRA CURRENTLY IN PROGRESS ALONG WIND SHIFT AXIS LOCATED OUT AHEAD OF FRONTAL BOUNDARY/DEWPOINT GRADIENT. EXPECT ACTIVITY TO CONTINUE INTO THE EVENING AS THE BOUNDARY SLOWLY SLIDES EASTWARD. IT WILL GET A BETTER PUSH EASTWARD AS THE NIGHT PROGRESSES WITH THE SHORTWAVE SEEN IN WATER VAPOR IMAGERY OVER THE NORTHERN PLAINS MARCHING INTO THE REGION. WILL KEEP SOME CHANCE FOR PCPN OVER THE EASTERN HALF OF THE AREA OVERNIGHT AND OVER THE FAR EAST THURSDAY MORNING UNTIL THE LARGE SCALE SUBSIDENCE ON THE BACKSIDE OF THE UPPER TROUGH FINALLY SCOURS THINGS OUT ACROSS THE FORECAST AREA. LOW LEVEL RIDGING WILL QUICKLY ESTABLISH ITSELF OVER THE AREA ON THURSDAY AS MUCH DRIER NORTHWESTERLY MID-UPPER LEVEL FLOW SETS UP. A WEAK SHORTWAVE WILL RIPPLE THROUGH THE UPPER FLOW ON FRIDAY... WHICH LOOKS TO PUSH A REINFORCING SHOT OF COOLER AIR SOUTH TOWARD THE REGION... BUT IT DOESN/T APPEAR THERE WILL BE SUFFICIENT MOISTURE... FORCING... OR INSTABILITY TO GET MUCH OUT OF IT AT THIS POINT IN TIME. CAN/T RULE OUT THE POSSIBILITY THAT A FEW SHRA COULD OCCUR FRIDAY AFTERNOON/EVENING... BUT PROBABILITY IS TOO LOW AT THIS POINT TO INCLUDE A MENTION. A MORE POTENT SHORTWAVE WILL APPROACH THE AREA SATURDAY NIGHT... BRINGING A BETTER CHANCE FOR PCPN. A WARM FRONT WILL FIRST LIFT NORTH THROUGH THE AREA SATURDAY NIGHT... WITH A COLD FRONT QUICKLY FOLLOWING IN BEHIND IT SUNDAY AFTERNOON INTO SUNDAY NIGHT. THE GFS MANAGES TO BUILD A FAIR AMOUNT OF INSTABILITY AHEAD OF THIS FEATURE... WITH MLCAPES AOA 2500 J/KG OVER A GOOD PART OF THE AREA. DECENT DEEP LAYER SHEAR IS ALSO PROGGED WITH 0-6KM VALUES AOA 40KT OVER MUCH OF THE AREA. SO... THINGS WILL AT LEAST NEED TO BEAR SOME WATCHING AS WE HEAD INTO THE WEEKEND WITH RESPECT TO SEVERE WEATHER POTENTIAL DEPENDING ON HOW THINGS SETUP AS WE DRAW NEARER TO THAT TIME FRAME. RIDGING LOOKS TO WORK BACK INTO THE AREA ON MONDAY... HELPING TO BRING AN END TO ANY PCPN ASSOCIATED WITH THE AFOREMENTIONED FRONTAL BOUNDARY AND SHORTWAVE. THE NEXT CHANCE FOR PCPN THEN LOOKS TO ARRIVE ON WEDNESDAY AS RETURN FLOW AND WARM ADVECTION MAY HELP TO GET SOME SHRA/TSRA GOING... PARTICULARLY OVER THE WESTERN HALF OF THE AREA. MODEL SOLUTIONS VARY SUBSTANTIALLY BY THE TIME WE REACH WEDNESDAY... WITH SIGNIFICANT TIMING AND AMPLITUDE DIFFERENCES DUE TO DISPARATE HANDLING OF A SIGNIFICANT UPPER TROUGH OVER THE WESTERN CONUS AND WESTERN CANADA. WILL UNDOUBTEDLY SEE SOME ADJUSTMENTS MADE TO THE MIDWEEK PORTION OF THE FORECAST OVER THE NEXT FEW DAYS AS THINGS HOPEFULLY COME INTO BETTER FOCUS. && .AVIATION.../18Z TAF ISSUANCE/ SURFACE BOUNDARY ORIENTED FROM JUST EAST OF KSTC SOUTHWARD TO KFRM. THIS WILL MOVE VERY SLOWLY EAST THIS AFTERNOON AND EVENING...TRIGGERING SHOWERS AND THUNDERSTORMS AS IT DOES. THESE WILL BE SLOW-MOVING THUNDERSTORMS...WITH ABOUT 50 TO 70 PERCENT COVERAGE FROM THE SOUTHERN TWIN CITIES SOUTHWARD...AND 20 TO 50 PERCENT COVERAGE NORTHWARD. THESE SHOULD MAINLY IMPACT WESTERN WISCONSIN FROM 23Z AND AFTER. SOME OF THE STORMS WILL PRODUCE BRIEF IFR VISIBILITIES BASED ON THEIR HEAVY RAINFALL POTENTIAL. ALSO...SOME BRIEF GUSTY WINDS ARE LIKELY. THE STORMS WILL BEGIN TO DISSIPATE IN COVERAGE BY 02Z WITH SHOWERS LINGERING ACROSS WESTERN WI THROUGH 06Z BEFORE FADING. THE BOUNDARY WILL BE SLOW TO MOVE THROUGH WESTERN WI...ALLOWING FOR THE LIKELIHOOD OF FOG DEVELOPMENT THERE OVER THE WET GROUND. OTHERWISE...SOME LINGERING MVFR CIGS NEAR WESTERN MN TAF SITES /KAXN AND KRWF/ SHOULD LIFT BY 21Z. WINDS WILL TURN WESTERLY AT ALL MN SITES BY 00Z AND WI SITES BY DAYBREAK THURSDAY. AFTER SOME MORNING FOG/STRATUS IN WESTERN WI...THE DAY SHOULD BRING JUST SOME SCATTERED CUMULUS AND WELCOME DRIER AIR. KMSP...THUNDERSTORMS WILL EXPAND ALONG THE BOUNDARY TO THE WEST OF THE AIRPORT. THESE WILL BE CLOSE TO THE AIRFIELD AND GIVEN 50 TO 70 PERCENT COVERAGE EXPECTED...HAVE CONTINUED MENTION IN A TEMPO. IT IS A FAIRLY LONG TEMPO PERIOD OF THREE HOURS FOR THUNDER...BUT GIVEN THE SLUGGISH NATURE OF THE BOUNDARY...FEEL IT STILL APPROPRIATE. BRIEF MVFR IS LIKELY...WITH IFR POSSIBLE. SOME WIND GUSTS OF 30 TO 40 KTS ARE PROBABLE WITH A FEW OF THE STORMS...AND WILL MONITOR CLOSELY TO SEE IF A TAF AMMENDMENT IS WARRANTED TO MENTION THE GUSTS. CONFIDENCE IN STORMS ENDING WITH VFR CONDITIONS BY 00Z IS MODERATE. THERE MAY BE SOME LINGERING MVFR CIGS WITHIN THE SHOWERS FROM 00Z TO 03Z...BUT CONFIDENCE IS TOO LOW TO MENTION AT THIS TIME. && .PREV DISCUSSION... /ISSUED 102 PM CDT WED JUL 7 2010/ OVERALL JUST SOME TIMING ADJUSTMENTS MADE TO THE FORECAST THIS AFTERNOON. THE VISIBLE SATELLITE CHANNEL...RADAR MOSAIC...AND OBSERVATIONS SHOW THE SURFACE BOUNDARY ORIENTED FROM NEAR FAIRMONT TO THE WESTERN TWIN CITIES METRO AREA...FURTHER NORTH TO MILLE LACS LAKE. REMNANT OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION IS ALSO WITHIN THIS AREA. TOWERING CUMULUS AND A FEW STORMS HAVE DEVELOPED ALONG THIS AS OF 100 PM. INCREASING LOW LEVEL SOUTHEAST WINDS ACROSS SOUTHEAST MINNESOTA HAS ENHANCED THE MOISTURE CONVERGENCE ALONG THE BOUNDARY. THE AIR MASS ALONG THE BOUNDARY IS RICH IN MOISTURE AND DIAGNOSTIC MODELS INDICATE MODERATE MLCAPE VALUES OF NEAR 1500 J/KG. ASSOCIATED SOUNDINGS INDICATE THAT CONVECTIVE TEMPERATURES HAVE OR WILL BE BREACHED HERE THROUGH 300 PM. THESE SHOULD ENHANCE IN COVERAGE SHOULD LATE AFTERNOON AND THEN EVOLVE EAST SOUTHEAST INTO THE EARLY EVENING. GENERALLY LIGHT 0-3KM FLOW AND PROPAGATION VECTORS ORIENTED PARALLEL TO THE SURFACE BOUNDARY WILL LEAD TO SLOW-MOVING THUNDERSTORM CORES. PRECIPITABLE WATERS HAVE NOT INCREASED MUCH SINCE THE 12Z RAOB /1.25 INCHES/...BUT LOCALLY HEAVY RAINFALL STILL LIKELY IN SOME OF THESE THUNDERSTORMS BASED ON THE AFOREMENTIONED MOVEMENT AND THE RICH LOW LEVEL MOISTURE. SOUNDINGS ALSO SHOW SOME POTENTIAL FOR WIDELY SCATTERED STRONGER DOWN BURSTS. HAVE CONTINUED MENTION IN THE HAZARDOUS WEATHER OUTLOOK. GIVEN THE 0-3KM CAPE AND AN AXIS OF SURFACE VORTICITY ALONG THE BOUNDARY...IT IS POSSIBLE FOR A FEW FUNNEL CLOUDS...BUT THE SETUP NOT IDEAL ENOUGH TO MENTION IN OTHER PRODUCTS AT THIS TIME. TORNADO POTENTIAL IS VERY LOW WITH WEAK 0-1 KM SHEAR AND AN UNFAVORABLE STORM MODE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && TRH/MTF
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 226 PM CDT WED JUL 7 2010 MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028- 081930- 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- 226 PM CDT WED JUL 7 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND SOUTHERN MINNESOTA...AND WEST CENTRAL WISCONSIN. .DAY ONE...THIS AFTERNOON AND TONIGHT ISOLATED STRONG THUNDERSTORMS...WITH THE THREAT OF VERY HEAVY RAINFALL...GUSTY WINDS OF 50 MPH...AND SMALL HAIL WILL OCCUR ACROSS MOST OF THE OUTLOOK AREA THROUGH EARLY THIS EVENING. THE BEST POTENTIAL OF NEAR SEVERE WIND GUSTS OF 60 MPH WILL OCCUR ACROSS EAST CENTRAL AND SOUTH CENTRAL MINNESOTA...AS WELL AS WEST CENTRAL WISCONSIN. PLEASE SEE THE LATEST RIVER STATEMENTS FOR THE MINNESOTA AND CROW RIVERS AS RECENT HEAVY RAINFALL HAS CAUSED THESE RIVERS TO REMAIN NEAR OR SLIGHTLY ABOVE FLOOD STAGE. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THUNDERSTORMS ARE POSSIBLE ACROSS THE OUTLOOK AREA LATE SATURDAY NIGHT INTO MONDAY... AND AGAIN ON WEDNESDAY. THERE MAY BE SOME POTENTIAL FOR STORMS WHICH DEVELOP ON SUNDAY TO BECOME SEVERE... BUT IT IS STILL TOO SOON TO DETERMINE THE SPECIFIC TIME FRAME WHEN SEVERE STORMS MIGHT OCCUR OR WHICH AREAS WHICH WOULD BE IMPACTED. THE MINNESOTA RIVER WILL REMAIN ELEVATED FROM NEW ULM... DOWNSTREAM TO SAVAGE THROUGH THIS WEEKEND. IN ADDITION...THE CROW RIVER WILL REMAIN ELEVATED AROUND DELANO THROUGH THIS WEEKEND. SEE THE LATEST RIVER STATEMENTS FOR MORE INFORMATION. .SPOTTER INFORMATION STATEMENT... DUE TO THE ISOLATED NATURE OF SEVERE THUNDERSTORMS THIS AFTERNOON OR EVENING...SKYWARN SPOTTER ACTIVATION IS NOT ANTICIPATED.
The Minneapolis radar (KMPX), 135 km away, was scanning. The volume nearest the first event began at 20:29 UTC.
2 flash flood. Local standard time, as filed.
Rainfall amounts were reported around 5.50 inches north of Huntley, and the far northwest corner of Faribault County. Flooding was observed in this area with rapid rises along the Blue Earth River.
A local weather observer reported 4.10 inches of rainfall in less than two hours. A local creek rose a few feet in less than an hour and caused some basement flooding in the town of Granada.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2010Every state in 2010This day in weather historyWarnings in Minnesota, July 2010
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: 231478, 248482.