Omaha/Valley, NE

Weather Forecast Office

May 16th Severe Weather Event Review

Overview

During the afternoon and evening hours of May 16th, severe thunderstorms affected many locations in southeast and east-central Nebraska and southwest Iowa. These storms produced primarily damaging wind gusts and large hail with the most intense activity occurring across Douglas and Washington counties were several wind gusts in excess of 70 mph were observed. In fact, an 85 mph wind gust was recorded at the National Weather Service Office in Valley, NE. In addition to the wind and hail, the storms produced heavy rainfall with multiple reports of amounts in excess of 2.50".

SPC Event Archive

Caption

Wind
Storm Reports
Rainfall
Environment

Wind:

Below is a loop of reflectivity and base velocity data from the Omaha/Valley, NE radar between 5:48 PM and 6:53 PM. This imagery clearly shows the evolution of the bow echo that affected east-central Nebraska on the evening of the 16th. Note the strong velocity signature associated with the intense storm located just north of the apex of the bow, which tracked across northwest Douglas and southern Washington counties. As mentioned in the overview, an 85 mph wind gust was recorded at the NWS in Valley, NE with multiple observations of 70-75 mph winds across southern Washington county. At Omaha/Eppley Field, a gust of 63 mph was measured.

Storm Reports

Interactive Storm Report Map	SPC Storm Reports


PRELIMINARY LOCAL STORM REPORT...SUMMARY NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA 1220 AM CDT WED MAY 17 2017 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0501 PM HAIL TAMORA 40.90N 97.22W 05/16/2017 E1.00 INCH SEWARD NE FIRE DEPT/RESCUE 0515 PM HAIL SEWARD 40.91N 97.10W 05/16/2017 M1.00 INCH SEWARD NE TRAINED SPOTTER 0535 PM HAIL 6 N VALPARAISO 41.17N 96.83W 05/16/2017 E1.25 INCH SAUNDERS NE PUBLIC QUARTER TO HALF DOLLAR SIZED HAIL 0538 PM HAIL 2 SSW FREMONT 41.41N 96.51W 05/16/2017 E1.75 INCH DODGE NE NWS EMPLOYEE QUARTER TO GOLFBALL HAIL 0551 PM HAIL FREMONT 41.44N 96.49W 05/16/2017 E1.75 INCH DODGE NE PUBLIC UP TO GOLFBALL SIZED HAIL 0605 PM HAIL WAVERLY 40.91N 96.53W 05/16/2017 E1.75 INCH LANCASTER NE PUBLIC GOLF BALLS AND 50MPH WINDS 0610 PM TSTM WND DMG 2 S YUTAN 41.21N 96.40W 05/16/2017 SAUNDERS NE BROADCAST MEDIA MULTIPLE TREE BRANCHES DOWN AND TREE SPLIT IN HALF 0610 PM TSTM WND GST VALLEY 41.31N 96.35W 05/16/2017 M85.00 MPH DOUGLAS NE NWS EMPLOYEE 74KT MEASURED GUST AT OMAHA/VALLEY NWS 0610 PM TSTM WND DMG VALLEY 41.31N 96.35W 05/16/2017 DOUGLAS NE PUBLIC SEVERAL POWER POLES DOWN IN VALLEY 0615 PM HAIL LINCOLN 40.82N 96.69W 05/16/2017 E1.00 INCH LANCASTER NE PUBLIC 40TH AND OLD CHENEY 0620 PM HAIL 6 S GRETNA 41.05N 96.24W 05/16/2017 E1.00 INCH SARPY NE TRAINED SPOTTER FLYING J TRUCK STOP 0625 PM TSTM WND DMG GRETNA 41.14N 96.24W 05/16/2017 SARPY NE PUBLIC TREE DOWN 168TH AND GILES 0630 PM HAIL OMAHA 41.26N 96.01W 05/16/2017 E1.00 INCH DOUGLAS NE PUBLIC 132ND AND GILES 0630 PM HAIL OMAHA 41.26N 96.01W 05/16/2017 E1.00 INCH DOUGLAS NE EMERGENCY MNGR QUARTERS REPORTED AT 124TH AND CENTER AND 144TH AND PACIFIC 0630 PM HAIL 15 W OMAHA 41.26N 96.30W 05/16/2017 E1.00 INCH DOUGLAS NE TRAINED SPOTTER LAKE ZORINSKY AREA 0630 PM HAIL OMAHA 41.26N 96.01W 05/16/2017 E1.00 INCH DOUGLAS NE PUBLIC 178TH AND HARRISON 0630 PM TSTM WND GST 2 WNW FORT CALHOUN 41.47N 96.06W 05/16/2017 M70.00 MPH WASHINGTON NE TRAINED SPOTTER 70MPH WINDS RECORDED BY AUTOMATED WEATHER STATION. 0634 PM TSTM WND GST 2 SSW PAPILLION 41.13N 96.06W 05/16/2017 E80.00 MPH SARPY NE TRAINED SPOTTER LARGE TREE LIMBS AND 2+ INCH DIAMETER BRANCHES DOWN 0635 PM HAIL S OMAHA 41.26N 96.01W 05/16/2017 E0.88 INCH DOUGLAS NE TRAINED SPOTTER NICKELS AND 50MPH WINDS 0635 PM TSTM WND DMG OMAHA 41.26N 96.01W 05/16/2017 DOUGLAS NE BROADCAST MEDIA TREES DAMAGED AT GENE LEAHY MALL AT 13TH AND DOUGLAS 0640 PM TSTM WND DMG OMAHA 41.26N 96.01W 05/16/2017 DOUGLAS NE BROADCAST MEDIA TREES DOWN AT AKSARBEN NEAR S 63RD 0640 PM TSTM WND DMG PAPILLION 41.16N 96.04W 05/16/2017 SARPY NE PUBLIC LARGE BRANCH DOWN 0640 PM TSTM WND GST 2 SSE OMAHA 41.24N 96.00W 05/16/2017 E50.00 MPH DOUGLAS NE PUBLIC NICKEL HAIL AND 50MPH WINDS 0640 PM HAIL GRETNA 41.14N 96.24W 05/16/2017 E1.00 INCH SARPY NE TRAINED SPOTTER HWY 6 S OF HWY 370 0644 PM TSTM WND GST OMAHA 41.26N 96.01W 05/16/2017 M63.00 MPH DOUGLAS NE ASOS 55KT GUST REPORTED AT OMAHA/EPPLEY 0645 PM HAIL UNADILLA 40.68N 96.27W 05/16/2017 E1.00 INCH OTOE NE EMERGENCY MNGR 0645 PM TSTM WND DMG BENNINGTON 41.37N 96.16W 05/16/2017 DOUGLAS NE BROADCAST MEDIA BLEACHERS BLOWN OVER AT BENNINGTON HIGH SCHOOL 0647 PM TSTM WND DMG BLAIR 41.54N 96.14W 05/16/2017 WASHINGTON NE BROADCAST MEDIA ROOF DAMAGE TO HOME IN BLAIR 0650 PM TSTM WND DMG MISSOURI VALLEY 41.56N 95.90W 05/16/2017 HARRISON IA BROADCAST MEDIA SEVERAL LARGE BRANCHES DOWN 0655 PM TSTM WND DMG UNDERWOOD 41.39N 95.68W 05/16/2017 POTTAWATTAMIE IA AMATEUR RADIO HEAVY TREE DAMAGE 23446 MAGNOLIA. BARN AND HOUSE DAMAGED. REPORTED POSSIBLE ROTATION 0657 PM NON-TSTM WND DMG COUNCIL BLUFFS 41.24N 95.86W 05/16/2017 POTTAWATTAMIE IA PUBLIC LARGE BRANCH AND POWERLINE DOWN 6TH AND WILLOW 0700 PM TSTM WND DMG OMAHA 41.26N 96.01W 05/16/2017 DOUGLAS NE BROADCAST MEDIA SMALL PLANE FLIPPED OVER AT EPPLEY 0700 PM HAIL WEEPING WATER 40.87N 96.14W 05/16/2017 M1.75 INCH CASS NE PUBLIC UP TO GOLF BALL SIZE HAIL 0700 PM HEAVY RAIN FRIEND 40.65N 97.28W 05/16/2017 M1.32 INCH SALINE NE TRAINED SPOTTER RAINFALL THROUGH 7PM. SOME DIME AND NICKEL-SIZED HAIL. 0700 PM HEAVY RAIN WILBER 40.48N 96.96W 05/16/2017 M1.00 INCH SALINE NE TRAINED SPOTTER RAINFALL THROUGH 7PM. 0700 PM HEAVY RAIN SWANTON 40.38N 97.08W 05/16/2017 M2.10 INCH SALINE NE TRAINED SPOTTER RAINFALL THROUGH 7PM. SOME WIND DAMAGE 5-INCH TREE BRANCH BROKEN OFF. 0700 PM HEAVY RAIN WESTERN 40.39N 97.20W 05/16/2017 M1.56 INCH SALINE NE TRAINED SPOTTER RAINFALL THROUGH 7PM. 0700 PM HEAVY RAIN WILBER 40.48N 96.96W 05/16/2017 M1.07 INCH SALINE NE TRAINED SPOTTER RAINFALL THROUGH 7PM. 0702 PM TSTM WND GST TEKAMAH 41.78N 96.22W 05/16/2017 E65.00 MPH BURT NE TRAINED SPOTTER 0720 PM TSTM WND DMG SHELBY 41.51N 95.45W 05/16/2017 SHELBY IA PUBLIC OUTBUILDINGS DAMAGED 0725 PM TSTM WND DMG 4 W SHELBY 41.51N 95.53W 05/16/2017 HARRISON IA NWS EMPLOYEE LARGE TREE UPROOTED 0735 PM TSTM WND GST 2 S HARLAN 41.62N 95.33W 05/16/2017 M60.00 MPH SHELBY IA AWOS HARLAN AWOS 0746 PM HAIL 2 S EAGLE 40.79N 96.43W 05/16/2017 E1.00 INCH CASS NE TRAINED SPOTTER 0824 PM TSTM WND DMG CLATONIA 40.46N 96.85W 05/16/2017 GAGE NE PUBLIC SEVERAL BROKEN TREES AND POWER OUTAGE

Rain Reports

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1043 AM CDT WED MAY 17 2017

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

0700 AM     HEAVY RAIN       7 WNW RAYMOND           41.00N 96.91W 
05/17/2017  M2.93 INCH       LANCASTER          NE   COCORAHS        

            RAINFALL 24 HOUR

0700 AM     HEAVY RAIN       4 SSW BELLEVUE          41.10N 95.95W 
05/17/2017  M2.84 INCH       SARPY              NE   COCORAHS        

            RAINFALL 24 HOUR

0700 AM     HEAVY RAIN       2 W ALVO                40.87N 96.42W 
05/17/2017  M2.71 INCH       CASS               NE   COCORAHS        

            RAINFALL 24 HOUR

0700 AM     HEAVY RAIN       4 NE HASTINGS           41.06N 95.44W 
05/17/2017  M3.72 INCH       MILLS              IA   PUBLIC          

            RAINFALL 24 HOUR

Environment

Synoptic Overview at 12z (courtesy of SPC)


Figure 1: 250-mb analysis	Figure 2: 300-mb analysis	Figure 3: 500-mb analysis

Figure 4: 700-mb analysis	Figure 5: 850-mb analysis	Figure 6: 925-mb analysis

Synoptic Overview at 00z (courtesy of SPC)


Figure 7: 250-mb analysis	Figure 8: 300-mb analysis	Figure 9: 500-mb analysis

Figure 10: 700-mb analysis	Figure 11: 850-mb analysis	Figure 12: 925-mb analysis

Surface Maps (courtesy of WPC)


Figure 13: 12z surface map	Figure 14: 15z surface map	Figure 15: 18z surface map

Figure 16: 21z surface map	Figure 17: 00z surface map	Figure 18: 03z surface map

Observed Soundings


Figure 19: 12z Omaha, NE sounding. Despite considerable mid-level moistening, an EML was present, most notably in the 800-600 mb layer.	Figure 20: 12z Topeka, KS sounding. Similar to the Omaha sounding, very steep lapse rates were sampled in the 800-500 mb layer.	Figure 21: 12z North Platte, NE sounding. Same as Omaha and Topeka, except the base of the EML is a bit higher.

Figure 22: 19z Omaha, NE sounding. The boundary-layer had deepened considerably since 12z with a notable amount of mid-level drying.	Figure 23: 19z Topeka, KS sounding. While the boundary layer depth was similar to that at 12z, moistening did occur. And similar to Omaha, considerable mid-level dry had taken place since 12z.	Figure 24: 00z Topeka, KS sounding.

Mesoscale Environment (courtesy of SPC)


Figure 25: Low-level lapse rates at 21z. Initial storm development occurred ahead of a weak front and within the axis of steep-lapse rates stretching from south-central into east-central Nebraska.	Figure 26: 700-500-mb lape rates at 21z. This chart simply shows the presence of a pronounced EML over the central Plains.	Figure 27: mlCAPE at 21z. The combination of steep lapse rates and modest boundary-layer moisture yielded a moderate to strongly unstable air mass ahead of the front by mid afternoon.

Figure 28: Effective bulk shear magnitude at 21z. While the strongest vertical shear resided within the post-frontal environment, sufficient shear magnitudes overlapped the frontal interface.	Figure 29: effective storm-relative helicity at 21z. The strongest low-level shear resided well to the east in central Iowa. Given the linear forcing along the front, the presence of a hot, deeply mixed boundary layer and strong instability, the setup was supportive of organized line segments and bowing structures capable of damaging winds and hail.

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