A slow moving cold front sagged southward through western Iowa and eastern Nebraska during the day on August 2nd. Ahead of the front during the early morning hours the nocturnal low-level jet increased ahead of the front.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS OAX wrote it up.
A slow moving cold front sagged southward through western Iowa and eastern Nebraska during the day on August 2nd. Ahead of the front during the early morning hours the nocturnal low-level jet increased ahead of the front. This allowed for isolated thunderstorms to develop in northeast Nebraska and move into west central Iowa during the early morning hours. Some of these thunderstorms reached severe limits with large hail the main threats. These thunderstorms dissipated in the morning hours, but as the instability increased during the afternoon thunderstorms redeveloped along the cold front. Vertical wind shear also increased during the afternoon as well with some of the thunderstorms becoming supercells producing large hail and damaging winds. The thunderstorms weakened by mid to late evening.
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 Omaha, NE wrote its last area forecast discussion before the first event at Aug 2, 5:17 PM CST, 28 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 617 PM CDT SUN AUG 2 2015 .UPDATE... ISSUED AT 615 PM CDT SUN AUG 2 2015 ATMOSPHERE AT 22Z WAS EXTREMELY UNSTABLE WITH SPC MESO PAGE WAS SHOWING 100 MB ML CAPE VALUES OVER 5000 J/KG ALONG SOUTHWARD MOVING FRONTAL BOUNDARY. EFFECTIVE SHEAR GENERALLY LESS THAN 30 KNOTS BUT SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE EVENING. && .SHORT TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 259 PM CDT SUN AUG 2 2015 MODELS ARE IN GOOD AGREEMENT ADVERTISING A QUITE NOTICEABLE COOLING TREND OVER THE NEXT SEVERAL DAYS. ALL THIS IN PART TO NW FLOW ALOFT BRINGING A CANADIAN AIR MASS INTO THE LOWER 48 WITH THE BRUNT OF CAA DROPPING DOWN THRU THE GREAT LAKES REGION. FOR TONIGHT...NAM12 BNDRY LYR MOISTURE/INSTABILITY IS QUITE OVERDONE IN COMPARISON TO GFS20 SOLUTION WITH THE LATEST ECM/CMC LENDING SUPPORT SHOWING TO A DRIER AIR MASS QUICKLY FILTERING IN. AND AT THIS POINT BELIEVE SMALL OVERNIGHT POPS IS REASONABLE. ON MONDAY THE BNDRY IS PROGGED TO STALL OUT IN THE VICINITY OF THE SRN CWA WITH CONVECTIVE INITIATION ON EDGE OF CAP. STRENGTHENING LLVL JET MONDAY NIGHT WILL THEN RESULT IN INCREASING AREAL COVERAGE OF PCPN ACTIVITY OVER THE CWA. SFC BNDRY ADVERTISED TO SLOWLY LIFT AND FOR THE MOST PART REMAIN IN THE GENERAL VICINITY OF THE NERN CWA TUESDAY WHERE AFTN INSTABILITY AXIS WILL SET UP PER THE NAM12/GFS20. WILL THEREFORE MAINTAIN FOCUS FOR POPS IN THOSE PORTIONS OF THE CWA. AS FOR WED...WILL CONTINUE SMALL POPS IN LIGHT OF VIGOROUS LITTLE VORT MAX TRACKING THRU. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 259 PM CDT SUN AUG 2 2015 MEDIUM RANGE MODELS IN GOOD AGREEMENT SHOWING LOW AMPLITUDE RIDGING PREVAILING OVER THE CONUS. GFS/ECM/CMC QPF PLACEMENT APPEAR TO BE GENERALLY SIMILAR...BUT BELIEVE THEY ARE SOMEWHAT EXCESSIVE THROUGHOUT THE EXTENDED PDS. AND FOR NOW ONLY MINOR TWEAKS MADE TO GOING POP FCST. REGARDING TEMPS...METEOGRAMS ACROSS THE CWA INDICATE BELOW NORMAL MAX TEMPS ARE IN STORE HEADING INTO NEXT WEEKEND WITH AFTN HIGHS GENERALLY IN THE UPPER 70S TO LOWER 80S. && .AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 615 PM CDT SUN AUG 2 2015 WIND SHIFT CONTINUED TO PUSH SOUTHWARD...AND SOME ISOLD TO SCT TSTMS HAD DEVELOPED AT OF 615 PM CDT. STORMS ARE MOST LIKELY TO AFFECT THE KLNK TAF SITE THIS EVENING AND INCLUDED A TEMPO GROUP FOR THAT WITH GUSTY WINDS AND MVFR VSBY. STORM CHANCES WILL CONTINUE OVERNIGHT BUT ITS TOO HARD TO PIN DOWN TIMING ON THAT FOR THE INDIVIDUAL TAF SITES. LOOKS LIKE ANY CEILINGS WOULD BE ABOVE 5000 FEET OUTSIDE OF TSTM ACTIVITY. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && UPDATE...MILLER SHORT TERM...DEE LONG TERM...DEE AVIATION...MILLER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 631 PM CDT SUN AUG 2 2015 IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034- 042>045-050>053-065>068-078-088>093-031330- MONONA-HARRISON-SHELBY-POTTAWATTAMIE-MILLS-MONTGOMERY-FREMONT- PAGE-KNOX-CEDAR-THURSTON-ANTELOPE-PIERCE-WAYNE-BOONE-MADISON- STANTON-CUMING-BURT-PLATTE-COLFAX-DODGE-WASHINGTON-BUTLER- SAUNDERS-DOUGLAS-SARPY-SEWARD-LANCASTER-CASS-OTOE-SALINE- JEFFERSON-GAGE-JOHNSON-NEMAHA-PAWNEE-RICHARDSON- 631 PM CDT SUN AUG 2 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR MOST OF EASTERN NEBRASKA AND PARTS OF SOUTHWEST IOWA. .DAY ONE...TONIGHT AND MONDAY ISOLATED TO SCATTERED THUNDERSTORMS WILL OCCUR OVER PARTS OF SOUTHEAST NEBRASKA AND SOUTHWEST IOWA THIS EVENING. A FEW STRONG TO SEVERE STORMS ARE POSSIBLE...WITH HAIL...GUSTY WINDS AND LOCALLY HEAVY RAIN. THERE IS ALSO A SMALL CHANCE OF STORMS OVERNIGHT AND ON MONDAY. THE BEST CHANCE OF STRONG STORMS WILL BE ACROSS SOUTHEAST NEBRASKA. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THERE IS A CHANCE OF THUNDERSTORMS MOST OF THE WEEK AS SEVERAL WEATHER IMPULSES MOVE ACROSS THE REGION. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED TONIGHT OR MONDAY...BUT PLEASE PASS ALONG ANY REPORTS OF LARGE HAIL OR WIND DAMAGE.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA 625 PM CDT SUN AUG 2 2015 IAZ069-079-090-030015- FREMONT IA-MILLS IA-POTTAWATTAMIE IA- 625 PM CDT SUN AUG 2 2015 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN POTTAWATTAMIE...CENTRAL MILLS AND NORTHWESTERN FREMONT COUNTIES UNTIL 715 PM CDT... AT 625 PM CDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR GLENWOOD...OR 19 MILES SOUTHEAST OF OMAHA...MOVING SOUTHEAST AT 10 MPH. NICKEL SIZE HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM. LOCATIONS IMPACTED INCLUDE... GLENWOOD...MALVERN...TABOR...SILVER CITY AND HASTINGS. THIS INCLUDES HIGHWAY 34 IN IOWA BETWEEN MILE MARKERS 9 AND 20. LAT...LON 4115 9580 4116 9557 4091 9539 4090 9570 TIME...MOT...LOC 2325Z 321DEG 8KT 4112 9570 ZAPOTOCNY
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
636 PM CDT SUN AUG 02 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0634 PM HAIL GLENWOOD 41.05N 95.74W
08/02/2015 E1.25 INCH MILLS IA PUBLIC
&&
MILLERPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
644 PM CDT SUN AUG 02 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0615 PM HAIL 1 NW GRANT 41.15N 95.00W
08/02/2015 E1.00 INCH MONTGOMERY IA PUBLIC
0615 PM HAIL 1 W GRANT 41.14N 95.00W
08/02/2015 E1.00 INCH MONTGOMERY IA PUBLIC
&&
LANDSVORKThe Omaha radar (KOAX), 66 km away, was scanning. The volume nearest the first event began at 23:43 UTC.
4 hail, 1 thunderstorm wind. Local standard time, as filed.
Three sections of the center pivot were overturned in a field.
The COOP Observer reported hail around 1 inch in diameter, but the public reported hail up to golf ball size.
Mostly smaller hail, but a few stones up to golf ball size.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Nebraska in 2015Every state in 2015This day in weather historyWarnings in Nebraska, August 2015
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: 587918, 587889, 587890, 587893, 587892.