Modestly unstable air that was in place over eastern Nebraska during the afternoon and evening of May 5th helped fuel thunderstorm development from central into northeast Nebraska. Also aiding thunderstorm development was a weak upper level disturbance that moved across the northern plains which pushed a weak surface trough into the region.
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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.
Modestly unstable air that was in place over eastern Nebraska during the afternoon and evening of May 5th helped fuel thunderstorm development from central into northeast Nebraska. Also aiding thunderstorm development was a weak upper level disturbance that moved across the northern plains which pushed a weak surface trough into the region.
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 May 5, 1:48 PM CST, 5 hours 34 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 248 PM CDT TUE MAY 5 2009 .DISCUSSION... ACTIVE ZONAL FLOW CONTINUES ACROSS THE CONUS. SUBJECTIVE 12Z UPPER AIR ANALYSIS INDICATES MAINLY ZONAL FLOW...WITH AN UPPER LOW OFF BC...ANOTHER DEEPER WAVE FROM NRN MN/NERN ND THROUGH WRN IA...AND UPPER RIDGE MOVING THROUGH THE ERN GT LAKES. A WEAKER SHORTWAVE WAS NOTED FROM WRN NEB THROUGH ERN NM...WITH SHORTWAVE RIDGE FROM CTRL NEB THROUGH CTRL TX. STRONGEST UPPER-LEVEL JET CORE EXTENDED FROM THE PAC INTO NRN CA/NV. AN 850MB FRONT EXTENDED FROM SRN SASK THROUGH CTRL DAKOTAS/WRN NEB TOWARD SECONDARY 850MB LOW DEVELOPING IN THE ROCKIES. MOISTURE REMAINS CONFINED TO THE SRN PLAINS/SERN STATES...WITH A 700MB CAP NOTED ACROSS SRN/CTRL TX WITH TEMPS 10-13C. FORECAST REMAINS ACTIVE WITH ZONAL FLOW CONTINUING TO PUSH ACROSS THE CONUS...WITH FREQUENT LOW-AMPLITUDE WAVES BUT ANY BUCKLING OF THE FLOW FAR INTO THE LONG-TERM. TIMING OF INDIVIDUAL WAVES IN THE PATTERN REMAINS TRICKY...AND FORECAST HAS LOW CONFIDENCE/HIGH BUST POTENTIAL. SHRA/TSRA LOOK LIKELY THIS EVNG/TONIGHT...WITH COVERAGE THE MAIN QUESTION. SOME ELEVATED INSTABILITY IS PROGGED /UP TO AROUND 500-1000 J/KG...BUT LOW-LEVEL MOISTURE DOES REMAIN A CONCERN...AND CONVECTION SHOULD REMAIN BELOW SEVERE LIMITS. AFTER THAT CONVECTION MOVES THROUGH...SHOULD SEE A BREAK TMRW IN PRECIP. SHOULD SEE SOME 850MB WARM AIR ADVECTION BEFORE MID-LEVEL FRONT MOVES THROUGH IN THE AFTN...THOUGH REMNANT CLOUDS MAY TEMPER HEATING...AND HAVE KEPT TEMPS JUST BELOW GUIDANCE. NEXT WAVE IS PROGGED TO MOVE THROUGH THE NRN PLAINS ON WED NT/THURS...DRAGGING A WEAK WIND SHIFT/COLD FRONT THROUGH THE CTRL PLAINS AND PROVIDING A FOCUS FOR PRECIP. KEPT CHC POPS THROUGH 00Z FRI WITH FAIRLY ROBUST SIGNAL AMONG ALL MODEL SOLUTIONS FOR PRECIP...THOUGH IT DOES APPEAR THAT MOST OF THE INSTABILITY WILL BE PUSHED SWD AS THE BOUNDARY PASSES THROUGH. AGAIN...SHOULD SEE A BREAK IN PRECIP FOR MOST OF THE AREA THURS NT/FRI...THOUGH MODELS HAVE SOME DISCREPANCY ON WHERE BOUNDARY HANGS UP /AND THEREFORE POTENTIAL FOR PRECIP IN SRN CWA/ AS WELL AS POTENTIAL WAVE MOVING THROUGH THE DAKOTAS AND CLIPPING THE NRN CWA WITH PRECIP. HAVE DROPPED MAX TEMPS FRI/SAT IN WAKE OF COLD FRONT...BUT KEPT PRECIP CHCS LOW OR NIL. PROGS ARE CONSISTENT FOR A SFC HIGH/MID-LEVEL RIDGE TO SLIDE THROUGH AROUND SAT...AND THAT STILL LOOKS LIKE THE BEST CHC FOR A QUIET WEATHER DAY. WARM AIR ADVECTION PICKS BACK UP ON SUN AS ANOTHER WAVE MOVES INTO THE CTRL US...WITH SOMEWHAT STRONG SFC LOW PROGGED TO DEVELOP IN THE LEE OF THE ROCKIES. MODELS HAVE BEEN RATHER AGGRESSIVE FOR SEVERAL RUNS IN BREAKING OUT PRECIP IN THE WAA/ISENTROPIC LIFT AHEAD OF THAT SYSTEM...AND HAVE ADDED CHC POPS TO PART OF THE CWA ON SUN. UNCERTAINTY INCREASES FROM THE LATE WEEKEND AND BEYOND AS MODELS DIFFER IN TIMING AND DEPTH OF A POTENTIAL WRN UPPER TROUGH/LOW...THUS HAVE PLAYED SAFE FOR NOW WITH NO PRECIP IN DAY 7. && .AVIATION... FOR TAF SITES KOFK/KOMA/KLNK. EXPECT VFR CONDITIONS TO PREVAIL AT ALL THREE TAF SITES THROUGH THE EVENING HOURS. SCATTERED SHRA AND TSRA WILL BE POSSIBLE...BUT DID NOT MENTION TSRA AT THIS TIME. SOUTH OR SOUTHWEST WINDS WILL BE SHIFTING TO THE NORTHWEST AS A COLD FRONT MOVES THROUGH WEDNESDAY. THERE DOES APPEAR TO BE SOME POTENTIAL FOR FOG AND POSSIBLY STRATUS LATE TONIGHT INTO WEDNESDAY MORNING. TRAJECTORIES WOULD BRING THE LOW CLOUDS CURRENTLY IN OK AND KS NORTHWARD INTO OUR AREA. THE NEXT SHIFT WILL HAVE TO MONITOR THAT. I INCLUDED A SCATTERED LAYER...BUT IT COULD BECOME A CEILING. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && MAYES/MILLER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 450 PM CDT TUE MAY 5 2009 IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034- 042>045-050>053-065>068-078-088>093-061200- 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- 450 PM CDT TUE MAY 5 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST IOWA...WEST CENTRAL IOWA...EAST CENTRAL NEBRASKA...NORTHEAST NEBRASKA AND SOUTHEAST NEBRASKA. .DAY ONE...TONIGHT AND WEDNESDAY ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS MUCH OF THE OUTLOOK AREA...PRIMARILY THIS EVENING. SEVERE WEATHER IS NOT ANTICIPATED. .DAYS TWO THROUGH SEVEN...WEDNESDAY NIGHT THROUGH MONDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TONIGHT OR WEDNESDAY. FOBERT
The Omaha radar (KOAX), 87 km away, was scanning. The volume nearest the first event began at 01:21 UTC.
1 hail. Local standard time, as filed.
Hail up to ping pong ball size was reported in and around the Wisner area.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Nebraska in 2009Every state in 2009This day in weather historyWarnings in Nebraska, May 2009
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: 157430.