Wednesday, November 14, 2012

Burnsville, Mendota Heights, West St. Paul MN. EF0 11/10/12

How strange.

Get a text from a buddy asking if I'd taken a look at the radar recently. Since we were out with friends at the time I had not. But I quick opened my phones radar app to give a little demonstration and lo and behold, a nice well defined line was approaching from the west giving the appearance that it was June instead of November.

While Downtown Minneapolis was abuzz with the final warm air of the year bringing out lots of folks to stroll and dine on the sidewalks of the city, we decided to make it an early night as our dining partners had children at home and we're just well, old...

And we knew what was coming next... Kind of.

We made it home in time to pop out on our deck and enjoy a cigar and scotch while enjoying the last few minutes of 68 degree air. All the while watching the radar images become a little more than what we expected.


Here we see the line approaching the metro. It was about this time tornado number one was forming according to the NWS.

The appearance of this cell just screamed rotation. This was doing damage at this point in Mendota Heights.
















 



Signature indicating a pretty sizable downburst occuring


Here's the front as it drops several downbursts to the Northeast affecting Mahtomedi and adjoining areas.


Here's the official MPX report:

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
420 PM CST TUE NOV 13 2012

...ONE MORE TORNADO CONFIRMED FROM SATURDAY EVENING BRINGING THE
TOTAL TO THREE - AND AN OVERVIEW OF NON-TORNADIC WIND DAMAGE...

YESTERDAY THE NATIONAL WEATHER SERVICE COMPLETED ITS SURVEY OF THE
DAMAGE IN THE SOUTH METRO.  ONE MORE BRIEF TORNADO IN FAR NORTHERN
MENDOTA HEIGHTS WAS DETERMINED TO HAVE OCCURRED.  A SECOND SURVEY OF
THE DAMAGE IN NORTHEASTERN MENDOTA HEIGHTS AND WEST ST PAUL
CONFIRMED THE FINDING THAT NORTHEASTERN MENDOTA HEIGHTS AND WEST ST
PAUL WERE HIT WITH WIDESPREAD DOWNBURST DAMAGE.

HERE IS A LISTING OF THE THREE TORNADOES IN DAKOTA COUNTY...ALL
RATED EF-0... FOLLOWED BY AN OVERVIEW OF THE DOWNBURST DAMAGE.


...TORNADO 1 /BURNSVILLE/...

START LAT/LON: 44.750, -93.300
END LAT/LON:   44.773, -93.253

START LOCATION: JUST NORTHEAST OF THE INTERSECTION OF MCANDREWS RD
                AND COUNTY ROAD 5.
END LOCATION:   JUST SOUTHWEST OF THE INTERSECTION OF BURNSVILLE
                PKWY AND HIGHWAY 11.

STRENGTH RATING: EF-0 WITH 80 MPH WINDS.

START TIME: 1058 PM SAT NOV 10
END TIME:   1101 PM SAT NOV 10

PATH LENGTH: 2.6 MILES
PATH WIDTH:  100 YARDS
INJURIES:    0
FATALITIES:  0

NARRATIVE:  AN EF-0 TORNADO SPUN UP JUST NORTHEAST OF THE
INTERSECTION OF COUNTY ROAD 5 AND MCANDREWS RD AND TRACKED NORTHEAST
TO JUST SOUTHWEST OF THE INTERSECTION OF BURNSVILLE PKWY AND HWY 11.
NUMEROUS TREES AND POWER LINES WERE BLOWN DOWN ALONG THE PATH...SOME
FELL ONTO HOUSES. A STOP SIGN WAS BENT ALL THE WAY TO THE GROUND AND
A GRILL LID WAS FLOWN ABOUT 200 YDS NEAR NICOLLET JR HIGH SCHOOL.
MAXIMUM WIND SPEEDS WERE AROUND 80 MPH.


...TORNADO 2 /FAR NORTHERN EAGAN/...

START LAT/LON: 44.851, -93.176
END LAT/LON:   44.858, -93.173

START LOCATION: NEAR SKYLINE DRIVE EAST OF HWY 13.
END LOCATION:   LOST SPUR GOLF COURSE JUST SOUTH OF I-494.

STRENGTH RATING: EF-0 WITH 75 MPH WINDS.

START TIME: 1105 PM SAT NOV 10
END TIME:   1106 PM SAT NOV 10

PATH LENGTH: 0.5 MILES
PATH WIDTH:  50 YARDS
INJURIES:    0
FATALITIES:  0

NARRATIVE:  A BRIEF EF-0 TORNADO SPUN UP NEAR SKYLINE DRIVE EAST OF
HWY 13 AND TRACKED NNE TO THE LOST SPUR GOLF COURSE JUST SOUTH OF
I-494. NUMEROUS TREES WERE BLOWN DOWN AND EXHIBITED A CONVERGENT
DAMAGE PATTERN. SOME TREES FELL ONTO HOUSES AND POWER LINES. THERE
WAS LITTLE STRUCTURAL DAMAGE FROM THE TORNADO. ESTIMATED WINDS 75
MPH. THE PARENT STORM THEN MOVED NORTHEAST AND PRODUCED WIDESPREAD
DOWNBURST DAMAGE...FROM THE SOUTHWEST CORNER OF MENDOTA HEIGHTS TO
THE EAST CENTRAL PART OF MENDOTA HEIGHTS NEAR HIGHWAY 110 AND DODD
ROAD...AND ON TO THE NORTHWESTERN PART OF WEST ST PAUL WHERE IT
MERGED WITH THE OTHER STORM.


...TORNADO 3 /FAR NORTHERN MENDOTA HEIGHTS/...

START LAT/LON: 44.906, -93.125
END LAT/LON:   44.911, -93.116

START LOCATION: 0.2 MILE SOUTHEAST OF HWY 13 AND WACHTLER AVENUE.
END LOCATION:   JUST SOUTHEAST OF HWY 13 AND SYLVANDALE ROAD.

STRENGTH RATING: EF-0 WITH 75 MPH WINDS.

START TIME: 1110 PM SAT NOV 10
END TIME:   1111 PM SAT NOV 10

PATH LENGTH: 0.5 MILES
PATH WIDTH:  50 YARDS
INJURIES:    0
FATALITIES:  0

NARRATIVE:  A BRIEF EF-0 TORNADO DEVELOPED JUST EAST OF LILYDALE AND
TRACKED NORTHEAST ACROSS A SUBDIVISION.  SEVERAL DOZEN LARGE TREES
OR BRANCHES FELL ON HOMES...VEHICLES OR SHEDS.  THE TREES EXHIBITED
A DEFINITE CONVERGENT DAMAGE PATTERN. ESTIMATED WINDS 75 MPH. AFTER
THE TORNADO DISSIPATED...WIDESPREAD DOWNBURST DAMAGE WAS NOTED
FROM THE NORTHEAST CORNER OF MENDOTA HEIGHTS INTO WEST ST PAUL
AND BEYOND.


...OTHER DAMAGE AREAS...

DOWNBURST DAMAGE OCCURRED IN LILYDALE...MENDOTA HEIGHTS...WEST ST
PAUL AND SOUTH ST PAUL.

THE STORM THAT PRODUCED THE TORNADO IN MENDOTA HEIGHTS HAD TRACKED
ACROSS LILYDALE...WHERE ABOUT A DOZEN TREES WERE DOWN WEST OF
I-35E... AND A FEW MORE TREES EAST OF I-35E.  THE TREES WERE
TYPICALLY ORIENTED FROM SOUTHWEST TO NORTHEAST AND THIS WAS LIKELY
DUE TO A REAR FLANK DOWNDRAFT.  AS THE STORM INTENSIFIED... THE REAR
FLANK DOWNDRAFT LIKELY WRAPPED AROUND SOME MORE AND IT WAS AT THIS
POINT THAT THE TORNADO TOUCHED DOWN IN FAR NORTHERN MENDOTA HEIGHTS.

THERE WERE TWO STORMS THAT CONVERGED UPON WEST ST PAUL. ONE WAS THE
STORM THAT WAS PRODUCING DOWNBURST DAMAGE MOVING NORTHEAST ALONG
DODD ROAD AND WHICH HAD EARLIER PRODUCED THE BURNSVILLE AND EAGAN
TORNADOES.  THE OTHER STORM IS THE ONE THAT HAD MOVED ACROSS
LILYDALE INTO FAR NORTHERN MENDOTA HEIGHTS.  ONCE THE MENDOTA
HEIGHTS TORNADO DISSIPATED AT 1111 PM... THE STORM EVOLVED INTO A
LARGE DOWNBURST... CAUSING NUMEROUS DOWNED TREES IN THE NORTHEAST
SECTION OF MENDOTA HEIGHTS AND THE NORTHERN PORTION OF WEST ST
PAUL... ESPECIALLY THE NORTHWEST CORNER.  THE ENTIRE DAMAGE PATTERN
ACROSS NORTHEASTERN MENDOTA HEIGHTS AND WEST ST PAUL WAS DIRECTED
TOWARD THE EAST... NORTHEAST AND NORTH...AND THERE WAS NO CONCLUSIVE
PROOF THAT IT WAS TORNADIC. INSTEAD IT WAS A VERY STANDARD PATTERN
OF DOWNBURST DAMAGE.  WINDS FROM THE DOWNBURST IN NORTHEASTERN
MENDOTA HEIGHTS AND WEST ST PAUL WERE LIKELY AROUND 75 MPH.  MANY OF
THE TREES LANDED ON HOMES AND VEHICLES...AND SOME GARAGES WERE
PUSHED OFF THEIR FOUNDATIONS. SOME OF THE MOST SIGNIFICANT DOWNBURST
DAMAGE WAS IN THE MANY BLOCKS SURROUNDING DODD ROAD AND DELAWARE.

DOWNBURST DAMAGE CONTINUED TO THE NORTHEAST. A SWATH OF SCATTERED
TREES AND BRANCHES WERE DOWN FROM THE WEST SIDE NEIGHBORHOOD OF ST
PAUL...NEAR ANNAPOLIS AND SMITH TO HOLMAN FIELD...WHERE A 70 MPH
GUST WAS RECORDED... THEN ACROSS THE RIVER TO MOUNDS PARK AND THEN
TO THE DAYTONS BLUFF NEIGHBORHOOD... NEAR JOHNSON PARKWAY AND
MINNEHAHA.  OCCASIONAL DOWNBURST DAMAGE ACTUALLY CONTINUED TO THE
NORTHEAST...ACROSS WASHINGTON COUNTY...INCLUDING MAHTOMEDI...GRANT
AND STILLWATER TOWNSHIP.

OTHER SPORADIC STRAIGHT LINE WIND DAMAGE OCCURRED BETWEEN THE
BURNSVILLE AND THE EAGAN TORNADOES....AND ALSO AFTER THE EAGAN
TORNADO HAD DISSIPATED...SPECIFICALLY FROM THE SOUTHWEST CORNER OF
MENDOTA HEIGHTS TO THE EAST CENTRAL PART OF MENDOTA HEIGHTS NEAR
HIGHWAY 110 AND DODD ROAD...AND ON TO THE NORTHWESTERN PART OF WEST
ST PAUL WHERE IT MERGED WITH THE OTHER STORM.


...NOVEMBER TORNADO CLIMATOLOGY...

TORNADOES IN NOVEMBER ARE EXCEEDINGLY RARE FOR MINNESOTA. SINCE THE
MODERN TORNADO DATABASE STARTED IN 1950...ONLY ONE TORNADO OCCURRED
IN NOVEMBER...11/1/2000 NEAR PRINSBURG IN KANDIYOHI COUNTY.
HOWEVER...THERE IS EVIDENCE OF TWO OTHERS PRIOR TO 1950...ONE ON
11/2/1938 IN ITASCA AND ST LOUIS COUNTIES...AND ANOTHER ON
11/16/1931 NEAR MAPLE PLAIN OF HENNEPIN COUNTY.


...METEOROLOGY OF THE EVENT...

THE NOVEMBER 10 TORNADOES WERE WEAK AND BRIEF DUE TO A LESS THAN
FAVORABLE ENVIRONMENT FOR TORNADO FORMATION. WHILE WIND SHEAR WAS
STRONG... INSTABILITY WAS VERY LOW MAKING THIS EVENT RATHER
ANOMALOUS. WIND SHEAR AND INSTABILITY ARE KEY INGREDIENTS FOR
TORNADOES AND SEVERE WEATHER.


...CAVEAT...

THE DATA ARE STILL CONSIDERED PRELIMINARY AND SUBJECT TO CHANGE
BASED ON ANY NEW INFORMATION PROVIDED OR GATHERED.

$$

BORGHOFF/JLT/KRAUSE







 

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