Warm advection kicked off a very narrow line of thunderstorms that turned severe after they crossed into western Iowa east of Omaha.
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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.
Warm advection kicked off a very narrow line of thunderstorms that turned severe after they crossed into western Iowa east of Omaha.
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 Mar 21, 2:37 AM CST, 2 hours 35 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 337 AM CDT WED MAR 21 2007 .DISCUSSION... ...SEVERE WEATHER POTENTIAL IS THE MAIN CONCERN... SURFACE WARM FRONT WAS ANALYZED AT 07Z FROM NEAR TOPEKA TO JUST NORTH OF CONCORDIA KANSAS...WITH UPPER 50S TO MID 60S DEWPOINTS BEHIND THE FRONT. RELATIVELY STRONG COLD FRONT WAS ANALYZED AT 07Z MOVING THROUGH NORTHWEST SOUTH DAKOTA. WATERVAPOR IMAGE SHOWING VORTICITY MAXIMAS MOVING INTO EASTERN NEBRASKA...SOUTHERN OKLAHOMA...AND SEVERAL WAVES ROTATING AROUND THE LARGE UPPER LOW MOVING THROUGH THE DESERT SOUTHWEST. NORTHERN STREAM WAVES ALSO SEEN OVER NORTHERN ROCKIES AND LEAD WAVE MOVING INTO WESTERN NORTH DAKOTA. NORMAN 00Z SOUNDING WAS QUITE MOIST BELOW 725 MB...WITH 50-55 KNOT LOW LEVEL JET ON PROFILERS ACROSS CENTRAL PLAINS. CONVECTION HAD ALREADY DEVELOPED TUESDAY EVENING ALONG THE 800MB WARM FRONT AND MOVED THROUGH THE CWA...WITH LINGERING ISOLATED CELLS STILL OVER WESTERN IOWA. OVERALL SYNOPTIC SCENARIO STILL ON TRACK... THAT OF COLD FRONT PUSHING THROUGH THE DESTABILIZING AIRMASS OVER NEBRASKA AND IOWA THIS AFTERNOON AND EVENING...WHILE SHORTWAVES PROVIDE DPVA. PREVIOUS RUNS OF MODELS WERE SUGGESTING A STRONGER CAPPING INVERSION AROUND 800 MB...BUT NEWEST RUNS SHOW A MUCH WEAKER CAP...AND MORE INSTABILITY. NAM 23Z FORECAST SOUNDING FOR LINCOLN HAD A 2500 J/KG MEAN LAYER CAPE VALUE WITH CINH DOWN TO 10-15 J/KG. HOWEVER... STRATUS CLOUD LAYER WILL LIKELY REMAIN IN PLACE THROUGHOUT MUCH OF THE DAY. BY LATE AFTERNOON...THE COLD FRONT SHOULD BE TO COLUMBUS...WITH STRONG VERTICAL MOTION ALONG AND AHEAD OF THE FRONT. WOULD STILL EXPECT JUST DISCRETE CONVECTIVE CELLS TO DEVELOP AS AS CAP IS SLOWLY BROKEN BETWEEN 22Z AND 01Z. THESE CELLS WOULD BE WORKING WITH 1500-2000 J/KG MLCAPE AND AROUND 40 KNOTS OF 0-6KM BULK SHEAR. A FEW STRONG TO SEVERE SUPERCELLS LOOK LIKELY LATE THIS AFTERNOON INTO THE EVENING HOURS FROM OUR SOUTHWEST COUNTIES INTO NORTH CENTRAL KANSAS...IT SOUTH AND WEST OF LINCOLN. WHETHER OR NOT THE SUPERCELLS WILL BE SURFACE BASED IS STILL QUESTIONABLE...BUT ANY UPDRAFTS ROOTED IN THE LOWER BOUNDARY LAYER WILL LIKELY HAVE ACCESS TO THE HORIZONTAL VORITICITY PROVIDED BY THE FRONT AS THE SUPERCELLS MOVE NEARLY PARALLEL TO THE FRONT...THUS RESIDENCE TIME FOR THE UPDRAFTS TO INGEST THE HORIZONTAL VORTICITY COULD BE RELATIVELY LONG. THIS WOULD INCREASE THE CHANCES FOR STRONGER ROTATION AND ASSOCIATED SEVERE WEATHER. A SLOWER FRONTAL MOTION WOULD OF COURSE BE LESS SUPPORTIVE OF THAT SCENARIO. MLLCL AND LFC HEIGHTS SHOULD BE DOWN AROUND 1000M AND 1500M RESPECTIVELY...ESPECIALLY GIVEN THE STRATO-CU INFLUENCED BOUNDARY LAYER. CAP WILL CONTINUE TO ERODE THROUGHOUT THE EVENING AS CONVECTION TRANSITIONS TO MORE LINEAR... PER SWODY1 DISCUSSION. POP FORECAST WAS ADJUSTED SLIGHTLY FOR TIMING OF THE FRONT AND TIMING OF THE CONVECTION...BUT RAIN STILL LOOKS LIKELY FOR MUCH OF THE FORECAST AREA TONIGHT. SOUTHERN COUNTIES MAY STILL SEE LINGERING SHOWERS THURSDAY. 00Z RUN OF THE GFS ADVERTISED A CLASSIC MINISUPERCELL PATTERN FOR SUNDAY WITH A STACKED CUTOFF UPPER LOW OVER GRAND ISLAND 00Z MONDAY...-20C 500 MB ISOTHERM JUST SOUTH OF HASTINGS... AND SURFACE LOW NEAR COLUMBUS. KNOWING THAT THOSE FEATURES WILL MOST LIKELY NOT BE EXACTLY WHERE THE GFS PUTS THEM 120 HOURS OUT KEEPS UNCERTAINTY ALIVE...BUT THAT PATTERN IS WELL WORTH KEEPING A CLOSE EYE ON FOR SUNDAY. GOING POPS REFLECT THE WET SOLUTION. TEMPERATURES NOT CHANGED SIGNIFICANTLY. THE HIGHS TODAY COULD BE TRICKY WITH THE STRATUS DECK. THE MET WAS SEVERAL DEGREES WARMER...BUT THE METMOS GOES SCATTERED BY 21Z. HOWEVER EVEN THE MAVMOS VALUES ARE A DEGREE OR TWO HIGHER THAN GOING FORECAST AND THE MAVMOS SEEMS TO KNOW ABOUT THE STRATUS. MADE ONLY MINOR ALTERATIONS TO HIGHS TODAY. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && NIETFELD
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 500 PM CDT TUE MAR 20 2007 IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034- 042>045-050>053-065>068-078-088>093-211000- ANTELOPE-BOONE-BURT-BUTLER-CASS-CEDAR-COLFAX-CUMING-DODGE-DOUGLAS- FREMONT IA-GAGE-HARRISON IA-JEFFERSON-JOHNSON-KNOX-LANCASTER-MADISON- MILLS IA-MONONA IA-MONTGOMERY IA-NEMAHA-OTOE-PAGE IA-PAWNEE-PIERCE- PLATTE-POTTAWATTAMIE IA-RICHARDSON-SALINE-SARPY-SAUNDERS-SEWARD- SHELBY IA-STANTON-THURSTON-WASHINGTON-WAYNE- 500 PM CDT TUE MAR 20 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN NEBRASKA AND SOUTHWEST IOWA. .DAY ONE...TONIGHT AND WEDNESDAY THERE WILL BE A CHANCE OF THUNDERSTORMS TONIGHT OVER ALL OF EASTERN NEBRASKA AND SOUTHWEST IOWA...MAINLY AFTER SUNSET. THUNDERSTORMS ARE ALSO POSSIBLE ON WEDNESDAY...MAINLY DURING THE LATE AFTERNOON. SOME STORMS MAY BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS. A COLD FRONT WILL MOVE INTO EASTERN NEBRASKA WEDNESDAY AFTERNOON WITH WARM AND UNSTABLE CONDITIONS IN PLACE ACROSS THE AREA AHEAD OF THE FRONT. .DAYS TWO THROUGH SEVEN...WEDNESDAY NIGHT THROUGH TUESDAY THUNDERSTORMS ARE LIKELY WEDNESDAY EVENING...THEN AGAIN FROM FRIDAY NIGHT INTO MONDAY. A FEW STORMS COULD BE SEVERE WEDNESDAY EVENING... WITH THE MAIN THREAT BEING DAMAGING WINDS AND LARGE HAIL. AN ACTIVE WEATHER PATTERN CONSISTING OF A FRONT IN THE PLAINS WILL KEEP THE CHANCES FOR THUNDERSTORMS IN THE FORECAST THROUGH THE WEEKEND. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED WEDNESDAY AFTERNOON. FOBERT
The Omaha radar (KOAX), 81 km away, was scanning. The volume nearest the first event began at 11:11 UTC.
1 hail. Local standard time, as filed.
Hail up to nickel size was reported near Oakland.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2007Every state in 2007This day in weather historyWarnings in Iowa, March 2007
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: 11997.