Event Summary for August 10th, 2020 Derecho

Tornadoes:

Tornado 1 - 6 SW Wakarusa, IN St. Joseph County Date August 10, 2020 Time (Local) 6:32 - 6:37 PM EDT EF Rating EF-1 Est. Peak Winds 110 mph Path Length 2.5 miles Max Width 100 yards Injuries/Deaths 0/0 Summary: The tornado began west of the intersection of Riley Road and Dogwood Road in southeast St. Joseph County.  It then tracked along and south of Riley Road. Widespread tree and structural damage occurred through this path.  Grain bins were toppled and farm outbuildings sustained damage.  The tornado tracked through several cornfields that resulted in significant crop damage. The tornado lifted east of Beech Road. Track Map Downloadable KMZ File

Tornado 2 - 1.0 NNW North Webster, IN Kosciusko County Date August 10, 2020 Time (Local) 6:55 - 7:00 PM EDT EF Rating EF-1 Est. Peak Winds 90 mph Path Length 3.1 miles Max Width 100 yards Injuries/Deaths 0/0 Summary: Trees were snapped west of State Route 13 as the tornado touched down. The tornado pushed over 2 power poles as it crossed SR 13, then continued southeast, causing a notable path of snapped trees and broken limbs. The debris was scattered throughout a nearby church parking lot. The church sustained minor loss of roof covering. Additional areas of tree damage were noted farther to the east-southeast. Some homes sustained damage as a result of falling trees and branches. The tornado crossed Webster Lake, coming onshore around EMS W17 Lane, where extensive tree damage occurred. Some residence damage was noted, both from the winds and falling trees. The tornado crossed East Backwater Road/East County Road 600 North and dissipated. Track Map Downloadable KMZ File

Tornado 3 - 1.1 S Burket, IN Kosciusko County Date August 10, 2020 Time (Local) 6:43 - 6:44 PM EDT EF Rating EF-0 Est. Peak Winds 80 mph Path Length 0.2 miles Max Width 50 yards Injuries/Deaths 0/0 Summary: A tornado touched down just west of the intersection of South County Road 700 North and South Beaver Dam Road, causing damage to trees to properties on either side of that intersection, with debris left on the roadway. A local fire chief witnessed the tornado lift over two structures and a grain bin with no noted damage. The tornado then touched down just east of the intersection in a mature corn field where it flattened a 100 to 150 foot circle in the corn, lifted briefly and then touched down again, causing the same type of damage before lifting again. The funnel attempted to touch down a third time but dissipated near a row of trees. Debris was still visible in the air. Track Map Downloadable KMZ File

The Enhanced Fujita (EF) Scale classifies tornadoes into the following categories:

EF0 Weak 65-85 mph	EF1 Moderate 86-110 mph	EF2 Significant 111-135 mph	EF3 Severe 136-165 mph	EF4 Extreme 166-200 mph	EF5 Catastrophic 200+ mph

Derecho:

This complex of storms that occurred on August 10, 2020 was known as a derecho. 

• A derecho produces a swath of particularly damaging thunderstorm winds over an area at least 400 miles long and 60 miles wide.
• These are primarily classified as straight-line winds rather than tornadic.
• Even so, wind speeds in a derecho can exceed 100 mph which is equivalent to that of an EF1 tornado but over a vastly larger area than a tornado would impact.
• Tornadoes can also be embedded within derechos and produce concentrated areas of even more intense damage.
• Derechos develop in an environment with very warm and moist air at the surface, colder air aloft, and moderate to strong winds at upper levels of the atmosphere.

Wind

Over 600 reports of severe wind speeds (58+ mph) or wind damage were received from Iowa through Illinois and into northern Indiana. Over 50 of those reports came were in the Northern Indiana County Warning Area. One fatality and one minor injury were reported in the Fort Wayne area.

This derecho produced widespread, significant wind damage in Iowa and Illinois. There were many reports of 75+ mph winds that caused widespread downed trees, semi trucks blown over, and structural damage to homes and businesses. These storm reports are preliminary.	The Storm Prediction Center has determined this event met all of the requirements to be classified as a derecho with a track of over 700 miles and over 600 storm reports. These storm reports are preliminary.	Preliminary Local Storm Reports for our area. Most of the damage was along the US-30 corridor but pockets of damage were observed in other areas such Berrien County, Michigan.	Northern Indiana has long been known as a corridor of enhanced derecho activity, as shown in this graphic from a published paper by Guastini & Bosart (2016) titled "Analysis of a Progressive Derecho Climatology and Associated Formation Environments".

Photos & Video 

Huntington County, IN

Tree damage in Huntington, IN. Courtesy of Huntington Co EMA.	Roof damage west in Roanoke, in vicinity. Courtesy of Huntington Co EMA.	Silo tipped over. Courtesy of Huntington Co EMA.	Tree downed and snapped. Courtesy of Huntington Co EMA.

SW of Wakarusa, IN Damage Survey (EF-1 tornado)

Crop damage from the tornado SW of Wakarusa, IN	Damage from tornado SW of Wakarusa, IN	Damage from tornado SW of Wakarusa, IN	Damage from tornado SW of Wakarusa, IN

1 mile N of North Webster, IN Damage Survey (EF-1 tornado)

Damage from tornado north of North Webster, IN	Damage from tornado north of North Webster, IN	Damage from tornado north of North Webster, IN	Damage from tornado north of North Webster, IN

Other damage photos

Wind damage from near Sitka, IN in White County. Photo courtesy of Britiney Jones.	Wind damage near Sitka, IN in White County. Photo courtesy of Christine Carlock Hoist	Tree down on road near Plymouth, IN in Marshall County.  Photo courtesy of Leona Reed.	Tree damage near Winona Lake, IN in Kosciusko County. Photo courtesy of Nick Deranek.

Tree damage near Leesburg, IN in Kosciusko County. Photo courtesy of Nick Deranek.	Shelf cloud over Warsaw, IN in Kosciusko County. Photo courtesy of Megan Dodson.	Shelf cloud near Columbus Grove, OH in Putnam County. Photo courtesy of Geddy Davis.	Shelf cloud near Converse, IN in Miami County. Photo courtesy of Weather Scoop

Radar

Overview

Line of storms moving across northern Indiana at approximately 6:30 PM EDT	This line included several segments of embedded strong wind gusts. Here the radar is sampling winds in excess of 75 mph just 300 ft AGL NE of Leesburg, IN. Numerous trees were downed in that area at 6:50 PM EDT.	As the line continued east, numerous pockets of damaging winds in excess of 60 mph were noted on radar. 7:15 PM EDT.	Regional radar loop showing the progression of the derecho from Iowa to Ohio.

Fort Wayne Area Straight Line Wind Damage and North Webster, IN tornadic storm

A very strong, straight-line wind signature was noted near Roanoke at 7:20 PM EDT. This caused numerous downed trees and some structural damage.	Another strong straight-line wind signature was observed just north of Fort Wayne at 7:30 PM EDT.	Another aspect of this setup was development of low level circulation with merging storms. Some evidence of low level rotation was noted around 7:10 PM EDT south of Columbia City, IN due to cell interactions.	Some weak rotation was noted east of Leesburg, IN around 6:48 PM EDT. This storm eventually went on to produce a tornado just north of North Webster, IN.  Details with the reflectivity and velocity become lost when the storms are too close to the radar due to the radar beam being at very low elevations.

Wakarusa Tornado

Radar indicated strong rotation just southwest of Wakarusa, IN at 6:35 PM EDT. Green indicates strong winds blowing toward the radar and red indicates strong winds blowing away from the radar. This "couplet" indicates strong rotation.	Here is radar reflectivity at the same time. Notice the small "nub" southwest of Wakarusa. This is a favored location for tornadogenesis along these multicell lines.	Here is the correlation coefficient just a few minutes later. Notice the "ball" of low CC/blue colors southwest of Wakarusa. The radar is sampling debris at this location.	Here is the reflectivity at the same time. Notice the "ball" of higher reflectivity southwest of Wakarusa. This corresponds to the low CC in the previous image and likely indicates debris.

Storm Reports

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE NORTHERN INDIANA
601 PM EDT TUE AUG 11 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0907 PM     TSTM WND DMG     2 S LIBERTY CENTER      41.42N 84.01W
08/10/2020                   HENRY              OH   EMERGENCY MNGR   

            LARGE TREE DOWN ON STATE 
            ROAD 109. TIME ESTIMATED FROM RADAR. 

0905 PM     TSTM WND DMG     3 W LIBERTY CENTER      41.44N 84.06W
08/10/2020                   HENRY              OH   EMERGENCY MNGR   

            DOWNED TREE ON COUNTY ROAD 
            10 BETWEEN COUNTY ROADS S AND T. TIME 
            ESTIMATED FROM RADAR. 

0839 PM     TSTM WND DMG     FAYETTE                 41.68N 84.34W
08/10/2020                   FULTON             OH   TRAINED SPOTTER  

            TREE DOWN ON ROAD, SUV STRUCK THE TREE THAT 
            WAS DOWN. NO REPORTED INJURIES. 

0826 PM     TSTM WND DMG     OHIO CITY               40.77N 84.62W
08/10/2020                   VAN WERT           OH   EMERGENCY MNGR   

            LARGE TREE DOWN IN OHIO CITY. TIME ESTIMATED 
            FROM RADAR. 

0813 PM     TSTM WND DMG     HICKSVILLE              41.30N 84.77W
08/10/2020                   DEFIANCE           OH   EMERGENCY MNGR   

            TREES AND POWER LINES DOWN ACROSS THE TOWN 
            OF HICKSVILLE. 

0813 PM     TSTM WND DMG     CONVOY                  40.92N 84.71W
08/10/2020                   VAN WERT           OH   EMERGENCY MNGR   

            LARGE TREE DOWN IN CONVOY. TIME ESTIMATED 
            FROM RADAR. 

0757 PM     TSTM WND DMG     2 W WOODBURN            41.13N 84.88W
08/10/2020                   ALLEN              IN   AMATEUR RADIO    

            SEMI WAS OVERTURNED. 

0740 PM     TSTM WND DMG     BUTLER CENTER           41.31N 85.14W
08/10/2020                   DE KALB            IN   LAW ENFORCEMENT  

            MULTIPLE TREES AND LARGE BRANCHES ACROSS SR 
            327 BETWEEN CR56 AND CR64. TIME ESTIMATED BY 
            RADAR. 

0738 PM     TSTM WND DMG     1 S NINE MILE           40.96N 85.23W
08/10/2020                   ALLEN              IN   AMATEUR RADIO    

            SEMI BLOWN ON ITS SIDE. 

0735 PM     TSTM WND DMG     4 SW LEO-CEDARVILLE     41.18N 85.07W
08/10/2020                   ALLEN              IN   PUBLIC           

            TOP HALF OF A 1 FOOT DIAMETER TREE SNAPPED 
            AT THE INTERSECTION OF LEO ROAD AND ARAPAHO 
            PASSOVER. 

0733 PM     TSTM WND DMG     3 NNW SALEM CENTER      41.63N 85.16W
08/10/2020                   STEUBEN            IN   EMERGENCY MNGR   

            POWER POLE SNAPPED IN LAKE ARROWHEAD AREA. 
            TIME ESTIMATED FROM RADAR. 

0732 PM     TSTM WND GST     2 S ROLLING HILLS       41.00N 85.27W
08/10/2020  M69 MPH          ALLEN              IN   TRAINED SPOTTER  



0730 PM     TSTM WND DMG     FORT WAYNE              41.07N 85.14W
08/10/2020                   ALLEN              IN   911 CALL CENTER  

            DISPATCH REPORTS TREES AND POWER LINES DOWN 
            IN FORT WAYNE. NO SPECIFIC DETAILS. 

0729 PM     TSTM WND DMG     KENDALLVILLE            41.45N 85.26W
08/10/2020                   NOBLE              IN   PUBLIC           

            LARGE TREE DOWN AND POWER LINES SNAPPED IN 
            KENDALLVILLE. TIME ESTIMATED FROM RADAR. 

0723 PM     TSTM WND DMG     1 W ROANOKE             40.96N 85.39W
08/10/2020                   HUNTINGTON         IN   EMERGENCY MNGR   

            NUMEROUS LARGE TREE BRANCHES DOWN ONTO A 
            HOUSE. 

0723 PM     TSTM WND DMG     1 NE BLUE LAKE          41.25N 85.35W
08/10/2020                   WHITLEY            IN   TRAINED SPOTTER  

            TREE DOWNED ONTO A HOUSE. TIME ESTIMATED 
            FROM RADAR. 

0721 PM     TSTM WND DMG     1 ENE BLUE LAKE         41.24N 85.35W
08/10/2020                   WHITLEY            IN   EMERGENCY MNGR   

            POWER POLES DOWNED. TIME ESTIMATED FROM 
            RADAR. 

0720 PM     TSTM WND DMG     3 WNW MARKLE            40.85N 85.39W
08/10/2020                   HUNTINGTON         IN   TRAINED SPOTTER  

            SEVERAL TREES DOWN BLOCKING ROAD NEAR 900N 
            AND 300E. DAMAGE ALSO TO A HOUSE. TIME 
            ESTIMATED FROM RADAR. 

0720 PM     TSTM WND DMG     2 SSE LAUD              41.03N 85.44W
08/10/2020                   WHITLEY            IN   EMERGENCY MNGR   

            TREE DOWNED ONTO A HOUSE WITH NOTABLE DAMAGE 
            TO THE HOUSE. TIME ESTIMATED FROM RADAR. 

0719 PM     TSTM WND DMG     1 WNW ROANOKE           40.97N 85.40W
08/10/2020                   HUNTINGTON         IN   TRAINED SPOTTER  

            METAL ROOF PARTIALLY TAKEN OFF OF A 
            BUILDING. TIME ESTIMATED FROM RADAR. 

0719 PM     TSTM WND DMG     2 N ROANOKE             40.99N 85.38W
08/10/2020                   HUNTINGTON         IN   PUBLIC           

            LARGE TREES DOWN ON A PROPERTY. TIME 
            ESTIMATED FROM RADAR. 

0717 PM     TSTM WND DMG     4 E ALBION              41.40N 85.35W
08/10/2020                   NOBLE              IN   LAW ENFORCEMENT  

            LARGE TREE DOWN. 

0716 PM     TSTM WND DMG     3 WNW MAHON             40.95N 85.43W
08/10/2020                   HUNTINGTON         IN   PUBLIC           

            25 FOOT TALL TREE DOWN ACROSS A FENCE. TRUNK 
            SNAPPED 2 OR 3 FEET FROM THE GROUND. TIME 
            ESTIMATED FROM RADAR. 

0716 PM     TSTM WND DMG     1 ENE HUNTINGTON        40.88N 85.50W
08/10/2020                   HUNTINGTON         IN   EMERGENCY MNGR   

            LARGE PORTION OF A TREE DOWN. PICTURE ON 
            TWITTER. 

0716 PM     TSTM WND DMG     3 WNW ROANOKE           40.98N 85.43W
08/10/2020                   HUNTINGTON         IN   EMERGENCY MNGR   

            CORN KNOCKED DOWN IN A FIELD. 

0714 PM     TSTM WND DMG     3 SE GOBLESVILLE        40.96N 85.47W
08/10/2020                   HUNTINGTON         IN   EMERGENCY MNGR   

            HEALTHY TREE SNAPPED AT THE BASE. PHOTO ON 
            TWITTER. 

0714 PM     TSTM WND DMG     1 ENE GOBLESVILLE       40.99N 85.49W
08/10/2020                   HUNTINGTON         IN   EMERGENCY MNGR   

            EMPTY GRAIN BIN TOPPLED. PHOTO ON TWITTER. 

0707 PM     TSTM WND DMG     1 N NORTH WEBSTER       41.34N 85.70W
08/10/2020                   KOSCIUSKO          IN   NWS EMPLOYEE     

            POWER LINES DOWN ON NORTH SIDE OF NORTH 
            WEBSTER. 

0705 PM     TSTM WND DMG     THREE RIVERS            41.95N 85.63W
08/10/2020                   ST. JOSEPH         MI   FIRE DEPT/RESCUE 

            SEVERAL REPORTS OR LARGE TREES DOWN IN THREE 
            RIVERS AREA. TIME ESTIMATED FROM RADAR. 

0705 PM     TSTM WND DMG     SOUTH WHITLEY           41.09N 85.63W
08/10/2020                   WHITLEY            IN   EMERGENCY MNGR   

            REPORTS OF TREES AND POWER LINES DOWN. TIME 
            ESTIMATED FROM RADAR. 

0705 PM     TSTM WND DMG     CROMWELL                41.41N 85.61W
08/10/2020                   NOBLE              IN   TRAINED SPOTTER  



0658 PM     TSTM WND DMG     1 N NORTH WEBSTER       41.33N 85.70W
08/10/2020                   KOSCIUSKO          IN   NWS EMPLOYEE     

            WIDESPREAD TREE DAMAGE AS WELL AS SOME 
            STRUCTURE DAMAGE FROM FALLING TREES IN THE 
            EPWORTH FOREST AREA. 

0657 PM     TSTM WND DMG     JAMES LAKE              41.31N 85.72W
08/10/2020                   KOSCIUSKO          IN   NWS EMPLOYEE     

            LARGE TREE DOWN. 

0656 PM     TORNADO          2 NE NORTH WEBSTER      41.34N 85.68W
08/10/2020                   KOSCIUSKO          IN   NWS STORM SURVEY 

            NWS STORM SURVEY CONCLUDED EF-1 TORNADO 
            OCCURRED. TORNADO TRACKED SOUTHEAST TO 1 
            MILE EAST OF NORTH WEBSTER BEFORE 
            DISSIPATING. TREES WERE SNAPPED WEST OF 
            STATE ROAD 13. A CHURCH SUSTAINED A LOSS OF 
            ROOF COVERING. SOME HOMES SUSTAINED DAMAGE 
            AS A RESULT OF FALLING TREES AND BRANCHES. 

0655 PM     TSTM WND DMG     NORTH MANCHESTER        41.01N 85.77W
08/10/2020                   WABASH             IN   EMERGENCY MNGR   

            LARGE TREE LIMBS DOWN IN NORTH MANCHESTER. 
            TIME ESTIMATED FROM RADAR. 

0654 PM     TSTM WND DMG     1 NNW WINONA LAKE       41.23N 85.82W
08/10/2020                   KOSCIUSKO          IN   BROADCAST MEDIA  

            A NUMBER OF LARGE TREE BRANCHES DOWN. 
            BRANCHES LOOK HEALTHY IN TWITTER PICTURE. 

0654 PM     TSTM WND DMG     LEESBURG                41.33N 85.85W
08/10/2020                   KOSCIUSKO          IN   PUBLIC           

            MULTIPLE LARGE TREE LIMBS DOWN IN LEESBURG. 
            TIME ESTIMATED FROM RADAR. 

0650 PM     TSTM WND DMG     1 N OSWEGO              41.34N 85.79W
08/10/2020                   KOSCIUSKO          IN   NWS EMPLOYEE     

            LARGE TREE DOWN ON THE ROAD. TIME ESTIMATED 
            FROM RADAR. 

0650 PM     TSTM WND DMG     1 SSW LEESBURG          41.32N 85.85W
08/10/2020                   KOSCIUSKO          IN   BROADCAST MEDIA  

            LARGE TREE BRANCH WAS DOWN ACROSS SR 15. 
            TREE SHOWS SOME ROT. 

0648 PM     TSTM WND DMG     1 N PERU                40.76N 86.07W
08/10/2020                   MIAMI              IN   PUBLIC           

            LARGE TREES DOWN IN PERU. TIME ESTIMATED 
            FROM RADAR. 

0645 PM     TSTM WND DMG     MONOQUET                41.28N 85.86W
08/10/2020                   KOSCIUSKO          IN   NWS EMPLOYEE     

            NEIGHBORHOOD OF NORTHWEST WOODS HAD THREE 
            TREES DOWNED, AROUND 1 TO 2 FT IN DIAMETER. 
            APPEARED REASONABLY HEALTHY. NUMEROUS SMALL 
            TO MEDIUM SIZED LIMBS DOWN, RANGING FROM 3 
            TO 8 INCHES IN DIAMETER. ESTIMATED 
            THUNDERSTORM WIND GUST AT AROUND 55 TO 60 
            MPH. 

0644 PM     TSTM WND DMG     1 N NAPPANEE            41.46N 85.98W
08/10/2020                   ELKHART            IN   PUBLIC           

            SEVERAL LARGE TREES DOWN IN NAPPANEE. TIME 
            ESTIMATED FROM RADAR. 

0640 PM     TORNADO          3 SW WAKARUSA           41.51N 86.05W
08/10/2020                   ELKHART            IN   TRAINED SPOTTER  

            NWS SURVEY CONFIRMED AN EF1 TORNADO ON AUGUST 11TH 2020.

0636 PM     TSTM WND DMG     OSCEOLA                 41.67N 86.08W
08/10/2020                   ST. JOSEPH         IN   TRAINED SPOTTER  

            TREES DOWN. 

0635 PM     TSTM WND DMG     4 E GRANGER             41.73N 86.06W
08/10/2020                   ELKHART            IN   PUBLIC           

            TREE AND POWER LINE DOWN OVER ROAD. VIA 
            TWITTER. 

0634 PM     TSTM WND DMG     1 S BENTON HARBOR       42.11N 86.45W
08/10/2020                   BERRIEN            MI   PUBLIC           



0633 PM     TSTM WND DMG     1 W BENTON HARBOR       42.12N 86.47W
08/10/2020                   BERRIEN            MI   PUBLIC           



0631 PM     TSTM WND DMG     FAIR PLAIN              42.09N 86.45W
08/10/2020                   BERRIEN            MI   PUBLIC           



0630 PM     TSTM WND DMG     ROCHESTER               41.06N 86.20W
08/10/2020                   FULTON             IN   TRAINED SPOTTER  

            REPORTS OF TREES DOWN. 

0630 PM     TSTM WND DMG     PLYMOUTH                41.35N 86.31W
08/10/2020                   MARSHALL           IN   PUBLIC           

            TREES AND POWER LINES DOWN ACROSS PLYMOUTH 
            AREA. TIME ESTIMATED FROM RADAR. 

0630 PM     TSTM WND DMG     2 N BOURBON             41.32N 86.12W
08/10/2020                   MARSHALL           IN   AMATEUR RADIO    

            TREES AND POWER LINES DOWN ALONG WITH PEA 
            SIZED HAIL. 

0630 PM     TSTM WND DMG     1 S SHOREHAM            42.05N 86.51W
08/10/2020                   BERRIEN            MI   PUBLIC           



0625 PM     TSTM WND GST     3 N BENTON HARBOR       42.15N 86.44W
08/10/2020  M67 MPH          BERRIEN            MI   ASOS             



0621 PM     TSTM WND DMG     BARODA                  41.96N 86.49W
08/10/2020                   BERRIEN            MI   EMERGENCY MNGR   

            SEVERAL TREES DOWN IN THE BARODA TOWNSHIP. 
            ADDITIONAL REPORTS OF TREES DOWN IN GRAND 
            BEACH, ST. JOSEPH, AND SURROUNDING AREAS. 

0620 PM     SEICHE           1 N SAINT JOSEPH        42.11N 86.49W
08/10/2020                   LMZ043             MI   NWS EMPLOYEE     

            FLOODING REPORTED AT LIONS PARK BEACH. WATER 
            LEVELS ABOUT 1.5 FEET ABOVE MEAN LEVEL. WIND 
            GUSTS ESTIMATED AT 40 TO 50 MPH. 

0616 PM     TSTM WND DMG     2 SW FAIR PLAIN         42.06N 86.48W
08/10/2020                   BERRIEN            MI   PUBLIC           

            ANSLEY AND LINCOLN IN SAINT JOSEPH TWP LARGE 
            TREE ~2 FT DIA DOWN ACROSS ROAD. 

0612 PM     TSTM WND DMG     2 E BARODA              41.96N 86.46W
08/10/2020                   BERRIEN            MI   PUBLIC           

            HOLLYWOOD RD AND WEST LEMON CREEK IN BARODA 
            TWP, WIND BLEW DOWN TRANSFORMER. 

0610 PM     TSTM WND DMG     IDAVILLE                40.76N 86.65W
08/10/2020                   WHITE              IN   PUBLIC           

            TREE ACROSS THE ROAD WITH A POWER LINE 
            ENTANGLED IN IT. THERE WAS ANOTHER POWER 
            LINE DOWNED IN TOWN BUT AN EXACT LOCATION 
            WAS NOT GIVEN. DELAYED REPORT. 

0610 PM     TSTM WND DMG     1 SSW SITKA             40.81N 86.75W
08/10/2020                   WHITE              IN   PUBLIC           

            1-2 FT DIAMETER TREE DOWNED BLOCKING THE 
            ROAD ON E 400 N NEAR RACCOON CIRCLE. DELAYED 
            REPORT. 

0610 PM     TSTM WND GST     2 E BREMS               41.34N 86.66W
08/10/2020  M63 MPH          STARKE             IN   AWOS             



0608 PM     TSTM WND DMG     SITKA                   40.83N 86.74W
08/10/2020                   WHITE              IN   PUBLIC           

            POWER LINE DOWNED AT 500N AND 700E. DELAYED 
            REPORT. 

0606 PM     TSTM WND DMG     GRAND BEACH             41.78N 86.79W
08/10/2020                   BERRIEN            MI   EMERGENCY MNGR   

            TREE ON POWER LINE (ON FIRE) IN GRAND BEACH. 

0605 PM     TSTM WND DMG     3 WNW SITKA             40.83N 86.79W
08/10/2020                   WHITE              IN   PUBLIC           

            TREE DOWNED ACROSS LOWES ROAD BRIDGE AND 
            BLOCKING TRAFFIC, APPROXIMATELY 1 FT IN 
            DIAMETER. DELAYED REPORT. 

0605 PM     HAIL             BARODA                  41.96N 86.49W
08/10/2020  E1.00 INCH       BERRIEN            MI   TRAINED SPOTTER  

            ESTIMATED WIND GUSTS AROUND 50 MPH WITH 
            SMALL TO MEDIUM SIZED TREE LIMBS DOWN. 

0548 PM     TSTM WND DMG     2 SSE HASKELL           41.46N 86.89W
08/10/2020                   LA PORTE           IN   PUBLIC           

            LARGE TREE DOWN. TIME ESTIMATED FROM RADAR. 

0542 PM     TSTM WND GST     2 WNW MICHIGAN CITY     41.72N 86.91W
08/10/2020  M56 MPH          LA PORTE           IN   C-MAN STATION    



0630 AM     TSTM WND DMG     2 WSW FLOWERFIELD       42.05N 85.69W
08/10/2020                   ST. JOSEPH         MI   PUBLIC           

            DELAYED REPORT OF WIND DAMAGE AROUND 
            MAYFIELD, MI ALONG WETHERBEE RD. A 1-2 FT 
            DIAMETER TREE WAS DOWNED, AND SEVERAL LIMBS 
            OF 6 INCHES TO 1 FT IN DIAMETER WERE BROKEN 
            OFF. 

0315 AM     LIGHTNING        2 WNW ROSELAND          41.73N 86.29W
08/10/2020                   ST. JOSEPH         IN   BROADCAST MEDIA  

            LIGHTNING STRIKE MAY HAVE RESULTED IN AN 
            APARTMENT COMPLEX FIRE. INVESTIGATION 
            ONGOING. 

0243 AM     TSTM WND DMG     3 NW ROSELAND           41.75N 86.31W
08/10/2020                   ST. JOSEPH         IN   BROADCAST MEDIA  

            HEALTHY LOOKING TREE PARTIALLY SNAPPED. VIA 
            TWITTER. TIME ESTIMATED FROM RADAR. 

Environment 

Thunderstorms began initially Sunday night across eastern South Dakota and eastern Nebraska. These storms intensified and grew into the derecho that eventually affected the local area by late Monday afternoon into Monday night.  An upper level disturbance originating from this convection allowed the storms to persist eastward.  The line of storms encountered a progressively more unstable air mass across eastern Iowa, northern Illinois, and northwest Indiana by the afternoon. This unstable air ahead of the line was made my possible by a warm and moist airmass coupled with very steep mid level lapse rates. There was just enough shear in the lowest 10,000 feet to support development of small circulations along the leading edge of this line of storms that led to the development of isolated tornadoes (southwest of Wakarusa, IN and just north of North Webster, IN).  The line of storms gradually weakened across northwest Ohio as the instability waned in the evening and as shear profiles became more marginal with eastward extent.

Figure 1: RAP analysis of 700 mb heights from 4pm on 8/10.20, winds, temps.  A short wave was moving across southern Minnesota/Iowa.	Figure 2: RAP analysis of effective shear from 6pm 8/10/20, The higher shear values were located just west into Illinois. The line of storms lost some organization as it tracked across N. Indiana/Lower Michigan	Figure 3: RAP analysis of mid level lapse rates from 6 pm 8/10/20. Lapse rates across the area were 7-8 deg C/km which helped generate strong instability

Near-storm environment summary.

Figure 4: RAP analysis of MLCAPE from 6pm 8/10/20.  Note the axis of strong instability of 2500-4000 J/kg nosing into northern Indiana.	Figure 5: RAP analysis of DCAPE from 6pm 8/10/20. Note the high levels of DCAPE (>1000 J/kg) in northern Indiana	Figure 6: The Derecho Composite Parameter from SPC from 5pm 8/10/20 indicated an environment favorable for sustaining the derecho into northwest Indiana.  This parameter takes into account several factors including instability and shear.