Event Summary: August 20, 2018

Overview

Heavy rain producing showers and thunderstorms were found across the area Monday, August 20, as a low pressure system spun over the area. One of the storms produced a tornado just east of Delmar, Iowa. In addition, heavy rains were also common with the stronger storms, where a quick 1 to 2 inches of rain fell. Some isolated areas picked up between 2 and 5 inches. One of the higher rainfall reports was 4.4 inches in Orangeville, Illinois. Temperatures topped out in the 70s and low 80s.

Event Summaries

SPC

Radar Loop
(20 August 2018 - 1:00 PM - 9:00 PM)

Tornado
Storm Reports
Rainfall
Environment

Tornado:

Tornado - 2 E Delmar
Clinton County

Date	08/20/2018
Time (Local)	3:49 PM - 3:51 PM CDT
Rating	EF-0
Est. Peak Winds	65 mph
Path Length	0.5 mile
Max Width	15 yards
Injuries/Deaths	0 / 0
Summary: Damage to soybeans and trees along its half mile path. A spotter report and videos were also used to determine time of tornado.

Track Map


Video near Delmar, IA by Jason Gooch (double click to enlarge)	Video near Delmar, IA by Jason Gooch (double click to enlarge)	Photo by: Karen Clemen

Local Rainfall Map	Radar Estimated Rainfall


CoCoRaHS Reports can be found here 24 hour precipitation reports (in Inches), for eastern Iowa, northwest and west central Illinois, and northeast Missouri. Reported between Midnight and 9 AM, Tuesday August 21, 2018. ....IOWA.... HAMPTON 2.25 BELLEVUE L AND D 12 2.25 TOLEDO 3N 1.93 NASHUA 2 SW 1.73 GARWIN 1.70 TRIPOLI 1.52 IOWA CITY 1.43 IOWA FALLS 1.42 CUBA CITY 1.40 DARLINGTON 1.37 MONTEZUMA 1 W 1.32 CHARLES CITY 1.24 NEW HAMPTON 1.10 ZEARING 1.06 CONRAD 1.03 MASON CITY 0.96 WILLIAMSBURG 1E 0.90 WAUCOMA 1WNW 0.90 ALEDO 0.82 MARSHALLTOWN 0.75 COGGON 0.74 MANCHESTER #2 0.71 GRINNELL 3 SW 0.70 WASHINGTON 0.63 LYNXVILLE DAM 9 0.63 VINTON 0.62 GRUNDY CENTER 0.57 GALESBURG 0.55 OSAGE 0.51 PRAIRIE CITY 2S 0.47 OSKALOOSA 0.42 DUBUQUE L & D 11 0.40 ELKADER 6 SSW 0.28 PELLA 1S 0.28 BUFFALO 0.23 MOUNT PLEASANT 1 SSW 0.20 KEOSAUQUA 0.19 CANTON 0.08 KEOKUK LOCK DAM 19 0.06 CENTERVILLE 0.06 RATHBUN DAM 0.06 SALEM 1 S 0.06 KEOKUK MUNICIPAL AP 0.04 AUGUSTA 0.00 ....ILLINOIS.... ARGYLE 3.04 ANAMOSA 3 SSW 2.90 GALENA 2.28 CASCADE 2.23 BRODHEAD 1.95 LOWDEN 1.50 OTTAWA 5SW 1.40 ROSCOE 2SE 1.36 DIXON 1W 1.30 FREEPORT WASTE WTR PL 1.23 DUBUQUE #3 0.99 ELIZABETH 0.93 ROANOKE 0.77 GENOA 2SW 0.75 DAVENPORT WFO 0.56 NORMAL 4NE 0.41 MOUNT PULASKI 0.40 MENDOTA 2 SE 0.37 STEUBEN 4 SE 0.35 KEWANEE 1 E 0.28 AVON 0.24 STEWARD 3S 0.16 MARSEILLES LOCK 0.15 PRAIRIE DU CHIEN 0.15 PAW PAW 2S 0.14 HAVANA 0.13 DE KALB 0.13 EARLVILLE 3S 0.08 ROCHELLE 0.05 QUINCY DAM 21 0.05 GUTTENBERG L AND D 10 0.00 ....MISSOURI.... MEMPHIS 0.12 CANTON L AND D 20 0.08 KIRKSVILLE 0.06 GREEN CITY 5N 0.04 DOWNING 0.04 ....WISCONSIN.... MIDDLETON 11.03 CHARMANY FARM 9.62 STOUGHTON 3.22 WATERTOWN 2.24 MAQUOKETA 4 W 1.98 WHITEWATER 1.80 FORT ATKINSON 1.75 MILTON WWTP 1.50 LAKE MILLS 1.33 AFTON 1.16 BELOIT 1.14 MUSCATINE 2N 1.06 ILLINOIS CITY DAM 16 1.01 LE CLAIRE L & D 14 0.66 ALTONA 0.56 NEW BOSTON DAM 17 0.30 CLINTON 0.30

Interactive Storm Report Map	SPC Storm Reports


PRELIMINARY LOCAL STORM REPORTS NATIONAL WEATHER SERVICE QUAD CITIES IA IL MON AUG 20 2018 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0756 PM HEAVY RAIN ORANGEVILLE 42.47N 89.64W 08/20/2018 M4.40 INCH STEPHENSON IL PUBLIC STORM TOTAL SO FAR WITH 1 INCH FROM THIS MORNING, AND 3.3 INCHES FROM THIS AFTERNOON/EVENING. RELAYED BY BROADCAST MEDIA. 0930 PM HEAVY RAIN HOPKINTON 42.35N 91.25W 08/20/2018 M4.25 INCH DELAWARE IA PUBLIC RELAYED BY KWWL. 0800 AM HEAVY RAIN FULTON 42.15N 90.68W 08/21/2018 M2.93 INCH JACKSON IA CO-OP OBSERVER CO-OP OBSERVER STATION FULI4, FULTON. 0700 AM HEAVY RAIN 3 SSW ANAMOSA 42.08N 91.30W 08/21/2018 M2.90 INCH JONES IA CO-OP OBSERVER 24-HR TOTAL. 0830 AM HEAVY RAIN BELLEVUE L/D 12 42.27N 90.42W 08/21/2018 M2.63 INCH JO DAVIESS IL MESONET MESONET STATION BLVI4, BELLEVUE L/D 12. 0600 AM HEAVY RAIN WEST AMANA 41.81N 91.97W 08/21/2018 M2.35 INCH IOWA IA COCORAHS COCORAHS STATION IA-IA-6, WEST AMANA. 0730 PM HEAVY RAIN 4 W CEDAR RAPIDS 41.98N 91.75W 08/20/2018 M2.32 INCH LINN IA PUBLIC 0726 AM HEAVY RAIN 2 SW SAINT DONATUS 42.35N 90.57W 08/21/2018 M2.30 INCH JACKSON IA TRAINED SPOTTER 24-HR TOTAL. 0700 AM HEAVY RAIN GALENA 42.42N 90.43W 08/21/2018 M2.28 INCH JO DAVIESS IL CO-OP OBSERVER CO-OP OBSERVER STATION GPBI2, GALENA. 0700 AM HEAVY RAIN CASCADE 42.30N 91.02W 08/21/2018 M2.23 INCH DUBUQUE IA CO-OP OBSERVER CO-OP OBSERVER STATION CASI4, CASCADE. 0700 AM HEAVY RAIN 1 NNW WILLIAMSTOWN 41.59N 91.75W 08/21/2018 M2.21 INCH JOHNSON IA COCORAHS COCORAHS STATION IA-JH-9, 1 NNW WILLIAMSTOWN. 0755 PM HEAVY RAIN 2 NNE STONE CITY 42.14N 91.33W 08/20/2018 E2.20 INCH JONES IA TRAINED SPOTTER 0800 AM HEAVY RAIN BELLEVUE 0.3 SSW 42.25N 90.43W 08/21/2018 M2.15 INCH JACKSON IA COCORAHS COCORAHS STATION IA-JC-5, BELLEVUE 0.3 SSW. 0345 AM HEAVY RAIN HOOVER CRK NEAR WEST BR 41.67N 91.35W 08/21/2018 M2.14 INCH CEDAR IA MESONET MESONET STATION WBRI4, HOOVER CRK NEAR WEST BRANCH. 0415 AM HEAVY RAIN WAPSI RVR AT ANAMOSA 42.08N 91.27W 08/21/2018 M2.05 INCH JONES IA MESONET MESONET STATION ANSI4, WAPSI RVR AT ANAMOSA. 0700 AM HEAVY RAIN 4 W MAQUOKETA 42.07N 90.70W 08/21/2018 M1.98 INCH JACKSON IA CO-OP OBSERVER CO-OP OBSERVER STATION MKTI4, 4 W MAQUOKETA. 0615 AM HEAVY RAIN 2 NNE MC CONNELL 42.47N 89.72W 08/21/2018 M1.82 INCH STEPHENSON IL COCORAHS COCORAHS STATION IL-SP-8, 2 NNE MC CONNELL. 0303 PM HEAVY RAIN 1 SW NORTH LIBERTY 41.73N 91.62W 08/20/2018 M1.75 INCH JOHNSON IA TRAINED SPOTTER 0715 AM HEAVY RAIN MONTICELLO 42.25N 91.17W 08/21/2018 M1.75 INCH JONES IA CO-OP OBSERVER CO-OP OBSERVER STATION MCLI4, MONTICELLO. 0700 AM HEAVY RAIN 3 N MARENGO 41.85N 92.06W 08/21/2018 M1.67 INCH IOWA IA COCORAHS COCORAHS STATION IA-IA-18, 3 N MARENGO. 0600 AM HEAVY RAIN DAVIS 42.43N 89.42W 08/21/2018 M1.66 INCH STEPHENSON IL COCORAHS COCORAHS STATION IL-SP-7, DAVIS. 0445 AM HEAVY RAIN GALENA TERRITORY 42.41N 90.35W 08/21/2018 M1.66 INCH JO DAVIESS IL MESONET MESONET STATION D7485, GALENA TERRITORY. 0630 AM HEAVY RAIN 3 NNE LAFAYETTE 42.20N 91.65W 08/21/2018 M1.62 INCH LINN IA COCORAHS COCORAHS STATION IA-LN-7, 3 NNE LAFAYETTE. 0700 AM HEAVY RAIN SHANNON 42.15N 89.74W 08/21/2018 M1.59 INCH CARROLL IL COCORAHS COCORAHS STATION IL-CR-13, SHANNON. 0652 PM HEAVY RAIN IOWA CITY ARPT 41.64N 91.55W 08/20/2018 M1.58 INCH JOHNSON IA ASOS ASOS STATION IOW, IOWA CITY ARPT. 0700 AM HEAVY RAIN 2 WSW CHADWICK 42.00N 89.94W 08/21/2018 M1.55 INCH CARROLL IL COCORAHS COCORAHS STATION IL-CR-4, 2 WSW CHADWICK. 0700 AM HEAVY RAIN 1 SW COLETA 41.89N 89.81W 08/21/2018 M1.55 INCH WHITESIDE IL COCORAHS COCORAHS STATION IL-WD-8, 1 SW COLETA. 0700 AM HEAVY RAIN MORSE 41.75N 91.43W 08/21/2018 M1.54 INCH JOHNSON IA COCORAHS COCORAHS STATION IA-JH-21, MORSE. 0640 AM HEAVY RAIN 1 WNW FREEPORT 42.31N 89.66W 08/21/2018 M1.52 INCH STEPHENSON IL COCORAHS COCORAHS STATION IL-SP-6, 1 WNW FREEPORT. 0655 AM HEAVY RAIN 1 WNW FREEPORT 42.30N 89.66W 08/21/2018 M1.51 INCH STEPHENSON IL COCORAHS COCORAHS STATION IL-SP-25, 1 WNW FREEPORT. 0953 PM HEAVY RAIN 3 W RIDOTT CORNERS 42.28N 89.54W 08/20/2018 M1.51 INCH STEPHENSON IL TRAINED SPOTTER 0700 AM HEAVY RAIN LOWDEN 41.87N 90.93W 08/21/2018 M1.50 INCH CEDAR IA CO-OP OBSERVER CO-OP OBSERVER STATION LWDI4, LOWDEN. 0704 AM HEAVY RAIN 1 NE OAKDALE 41.71N 91.59W 08/21/2018 M1.50 INCH JOHNSON IA TRAINED SPOTTER 0521 AM HEAVY RAIN PARNELL 41.58N 92.01W 08/21/2018 M1.44 INCH IOWA IA COCORAHS COCORAHS STATION IA-IA-13, PARNELL. 0445 AM HEAVY RAIN 3 E IOWA CITY 41.65N 91.48W 08/21/2018 M1.42 INCH JOHNSON IA MESONET MESONET STATION C5749, 3 E IOWA CITY. 0655 AM HEAVY RAIN MONTICELLO ARPT 42.22N 91.16W 08/21/2018 M1.30 INCH JONES IA AWOS AWOS STATION MXO, MONTICELLO ARPT. 0415 AM HEAVY RAIN CEDAR RVR AT VINTON 42.17N 92.02W 08/21/2018 M1.26 INCH BENTON IA MESONET MESONET STATION VINI4, CEDAR RVR AT VINTON. 0700 AM HEAVY RAIN NORTH ENGLISH 41.52N 92.07W 08/21/2018 M1.25 INCH IOWA IA CO-OP OBSERVER CO-OP OBSERVER STATION NENI4, NORTH ENGLISH. 0700 AM HEAVY RAIN 2 S ANDOVER 41.26N 90.29W 08/21/2018 M1.25 INCH HENRY IL COCORAHS COCORAHS STATION IL-HY-16, 2 S ANDOVER. 0415 AM HEAVY RAIN CEDAR RVR NEAR PALO 42.07N 91.78W 08/21/2018 M1.25 INCH LINN IA MESONET MESONET STATION PLOI4, CEDAR RVR NEAR PALO. 0459 AM HEAVY RAIN VINTON 42.15N 92.03W 08/21/2018 M1.24 INCH BENTON IA MESONET MESONET STATION C2988, VINTON. 0630 PM HEAVY RAIN 1 NW DAVENPORT 41.56N 90.61W 08/20/2018 M1.24 INCH SCOTT IA TRAINED SPOTTER 0630 AM HEAVY RAIN 3 W RICHMOND 41.46N 91.76W 08/21/2018 M1.20 INCH WASHINGTON IA COCORAHS COCORAHS STATION IA-WS-7, 3 W RICHMOND. 0458 AM HEAVY RAIN 1 ENE OAK GROVE 41.42N 90.55W 08/21/2018 M1.19 INCH ROCK ISLAND IL MESONET MESONET STATION D2227, 1 ENE OAK GROVE. 0700 AM HEAVY RAIN 1 N MUSCATINE 41.44N 91.07W 08/21/2018 M1.15 INCH MUSCATINE IA COCORAHS COCORAHS STATION IA-MC-10, 1 N MUSCATINE. 0730 AM HEAVY RAIN 2 ENE BOLTON 42.27N 89.68W 08/21/2018 M1.14 INCH STEPHENSON IL COCORAHS COCORAHS STATION IL-SP-26, 2 ENE BOLTON. 0455 AM HEAVY RAIN 1 NNE OLIN 42.02N 91.13W 08/21/2018 M1.14 INCH JONES IA MESONET MESONET STATION D2485, 1 NNE OLIN. 0500 AM HEAVY RAIN CORALVILLE DAM 41.72N 91.53W 08/21/2018 M1.14 INCH JOHNSON IA MESONET MESONET STATION CRVI4, CORALVILLE DAM. 0625 AM HEAVY RAIN 1 NW MARION 42.06N 91.61W 08/21/2018 M1.13 INCH LINN IA COCORAHS COCORAHS STATION IA-LN-27, 1 NW MARION. 0845 PM HEAVY RAIN 2 NNE CEDAR RAPIDS 42.01N 91.66W 08/20/2018 M1.12 INCH LINN IA TRAINED SPOTTER 0803 AM HEAVY RAIN 2 ENE CEDAR RAPIDS 42.00N 91.63W 08/21/2018 M1.12 INCH LINN IA MESONET MESONET STATION CDRPD, 2 ENE CEDAR RAPIDS. 0445 AM HEAVY RAIN URBANA 42.22N 91.88W 08/21/2018 M1.12 INCH BENTON IA MESONET MESONET STATION AV038, URBANA. 0639 PM HEAVY RAIN JESUP 42.48N 92.07W 08/20/2018 M1.10 INCH BUCHANAN IA TRAINED SPOTTER 0500 AM HEAVY RAIN 1 NW GENESEO 41.47N 90.18W 08/21/2018 M1.09 INCH HENRY IL COCORAHS COCORAHS STATION IL-HY-8, 1 NW GENESEO. 0700 AM HEAVY RAIN 2 N MUSCATINE 41.47N 91.04W 08/21/2018 M1.06 INCH MUSCATINE IA CO-OP OBSERVER CO-OP OBSERVER STATION MSTI4, 2 N MUSCATINE. 0700 AM HEAVY RAIN 2 ENE CALAMUS 41.84N 90.73W 08/21/2018 M1.06 INCH CLINTON IA COCORAHS COCORAHS STATION IA-CN-2, 2 ENE CALAMUS. 0656 AM HEAVY RAIN CLINTON ARPT 41.83N 90.33W 08/21/2018 M1.05 INCH CLINTON IA AWOS AWOS STATION CWI, CLINTON ARPT. 0700 AM HEAVY RAIN 4 S ANDOVER 41.24N 90.30W 08/21/2018 M1.05 INCH HENRY IL COCORAHS COCORAHS STATION IL-HY-17, 4 S ANDOVER. 0700 AM HEAVY RAIN 1 WNW CHARLOTTE 41.98N 90.50W 08/21/2018 M1.04 INCH CLINTON IA COCORAHS COCORAHS STATION IA-CN-17, 1 WNW CHARLOTTE. 0653 PM HEAVY RAIN DUBUQUE ARPT 42.40N 90.71W 08/20/2018 M1.01 INCH DUBUQUE IA ASOS ASOS STATION DBQ, DUBUQUE ARPT. 0600 AM HEAVY RAIN ILLINOIS CITY L/D 16 41.42N 91.02W 08/21/2018 M1.01 INCH ROCK ISLAND IL MESONET MESONET STATION ILNI2, ILLINOIS CITY L/D 16. 0530 AM HEAVY RAIN 2 SSE DAVENPORT 41.53N 90.59W 08/21/2018 M1.01 INCH SCOTT IA COCORAHS COCORAHS STATION IA-ST-4, 2 SSE DAVENPORT. 0800 PM HEAVY RAIN 1 WNW MORRISON 41.81N 89.98W 08/20/2018 M1.00 INCH WHITESIDE IL TRAINED SPOTTER 12 HR TOTAL. 0652 PM HEAVY RAIN QUAD CITY INTL ARPT 41.45N 90.51W 08/20/2018 M1.00 INCH ROCK ISLAND IL ASOS ASOS STATION MLI, QUAD CITY INTL ARPT. 0630 AM HEAVY RAIN ELIZABETH 42.33N 90.25W 08/21/2018 M0.93 INCH JO DAVIESS IL CO-OP OBSERVER CO-OP OBSERVER STATION EZBI2, ELIZABETH. 0700 AM HEAVY RAIN MANCHESTER 42.47N 91.45W 08/21/2018 M0.71 INCH DELAWARE IA CO-OP OBSERVER CO-OP OBSERVER STATION MHRI4, MANCHESTER. 0700 AM HEAVY RAIN 1 N MANCHESTER 42.50N 91.46W 08/21/2018 M0.62 INCH DELAWARE IA COCORAHS COCORAHS STATION IA-DW-9, 1 N MANCHESTER. 0700 AM HEAVY RAIN ASBURY 42.51N 90.77W 08/21/2018 M0.61 INCH DUBUQUE IA COCORAHS COCORAHS STATION IA-DB-20, ASBURY. 0349 PM TORNADO 3 ENE DELMAR 42.01N 90.55W 08/20/2018 CLINTON IA TRAINED SPOTTER TORNADO ON THE GROUND WITH TREE DEBRIS OFF TO THE NORTHEAST MOVING NORTHWEST. &&


Figure 1 SPC Day 1 Outlook (20:00 UTC)	Figure 2 SPC Day 1 Tornado Outlook (20:00 UTC)	Figure 3 SPC Day 1 Wind Outlook (20:00 UTC)


Figure 5 DVN Sounding 8/20/18 12z	Figure 6 ILX Sounding 8/20/18 12z

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