Long term dry soil conditions and low flows on the Missouri River contributed to lingering drought at the start of May. The severe to extreme drought steadily abated as precipitation increased during the first part of the month, with the sensitivity of the area to potential dry summer periods decreasing.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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 FSD wrote it up.
Long term dry soil conditions and low flows on the Missouri River contributed to lingering drought at the start of May. The severe to extreme drought steadily abated as precipitation increased during the first part of the month, with the sensitivity of the area to potential dry summer periods decreasing.
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 Sioux Falls, SD wrote its last area forecast discussion before the first event at Apr 30, 9:52 PM CST, 2 hours 8 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SIOUX FALLS SD 1052 PM CDT TUE APR 30 2013 .UPDATE... ISSUED AT 858 PM CDT TUE APR 30 2013 ANOTHER FAIRLY COMPLEX SET UP TO START THE MONTH OF MAY AFTER A BUSY LAST COUPLE OF WEEKS OF APRIL. TWO AREAS OF PRECIPITATION ONGOING AT 2Z. THE AREA TO THE NORTH AND WEST IS ASSOCIATED WITH THE VERY STRONG UPPER LEVEL JET AND LIKELY A MID LEVEL FRONT AROUND 700MB. THE CONVECTIVE ACTIVITY TO THE SOUTH AND EAST ALSO BEING FORCED BY THE STRONG JET TO THE NORTHEAST BUT THE SOURCE OF FRONTAL LIFT A LITTLE LOWER AROUND 800MB AND IN THIS LOWER LAYER THERE IS MUCH MORE UNSTABLE AIR TO WORK WITH. IN FACT THE 0Z OMA SOUNDING SHOWED A VERY NICE ELEVATED MIXED LAYER ABOVE ABOUT 750MB WHICH COINCIDES WELL WITH MODEL SUGGESTIONS. BACKING WINDS IN THE 800-600MB LAYER AS THE WAVE APPROACHES WILL ALLOW FOR ADDITIONAL CONVECTIVE DEVELOPMENT INTO CENTRAL NEBRASKA FROM ABOUT 4Z THROUGH 7Z WHICH WILL THEN LIFT NORTHEAST THROUGH TOMORROW MORNING. THE FORCING/COOLING ALOFT FROM THE UPPER LEVEL JET CIRCULATION WILL BEGIN TO MERGE WITH THE CONVECTIVE AREA OVER SOUTHEAST SOUTH DAKOTA BY ABOUT 10Z TO 14Z TONIGHT AND THIS IS WHERE IT GETS COMPLICATED. COULD VERY WELL SEE A CORRIDOR OF VERY ENHANCED LIFT/COOLING WHICH WOULD ALLOW A RELATIVELY SKINNY AREA TO CHANGE TO SNOW WHILE TO THE NORTHWEST AND SOUTHEAST OF THIS AREA IT COULD REMAIN MAINLY RAIN. THE ATMOSPHERE IS BARELY SUPPORTIVE OF SNOW BUT WITHIN THE STRONGEST LIFT IT SHOULD CHANGE OVER. VERY CLOSE TO ISSUING A SNOW ADVISORY FROM ABOUT HUTCHINSON COUNTY TO TURNER/LINCOLN/MINNEHAHA INTO PARTS OF SOUTHWEST MINNESOTA FOR TOMORROW MORNING AS SNOWFALL RATES COULD BE PRETTY IMPRESSIVE RIGHT OVER THE MORNING RUSH. MUCH OF THIS SNOW WILL MELT ON ROADWAYS BUT THIS COULD CAUSE SLICK DRIVING CONDITIONS. CONFIDENCE NOT QUITE HIGH ENOUGH ON LOCATION RIGHT NOW BUT PEOPLE MAY WANT TO PLAN AHEAD FOR A SLOWER COMMUTE TOMORROW MORNING AND POSSIBLE HEADLINES AS CONFIDENCE GROWS IN JUST WHERE THIS BAND COULD SET UP. UPDATE ISSUED AT 707 PM CDT TUE APR 30 2013 MADE A FEW MODIFICATIONS TO THE GOING FORECAST. SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOPED OVER NORTHWEST IOWA AND SUSPECT THAT THIS TREND MAY CONTINUE. THE 850MB TO 700MB LIFTED INDICES ARE RUNNING ABOUT -4 TO -5 C INTO SOUTHEASTERN PARTS OF NEBRASKA LATE THIS AFTERNOON. WHILE ELEVATED INSTABILITY WEAKENS A BIT THIS EVENING THE DEVELOPING TROUGH TO THE NORTHWEST BACKS THE LOW TO MID LEVEL WIND ADVECTING THIS MORE UNSTABLE AIR INTO CENTRAL PARTS OF NEBRASKA TOWARDS THE SIOUX CITY AREA. INCREASED QPF AMOUNTS A BIT AND SETTLED THE HIGHEST POPS JUST A TOUCH SOUTH OF WHERE THEY WERE EARLIER. LATEST HIGHER RESOLUTION MODELS DO INDICATE THAT THIS CONVECTIVE BAND DEVELOPING COULD BECOME THE MORE PREDOMINANT BAND AND THIS MAY BRING A MORE QUICK DROP OFF TO RAIN/SNOW ON THE NORTHWEST SIDE OF THIS BAND. NO MAJOR CHANGES EXPECTED AT THIS TIME AND WILL FOLLOW TRENDS THROUGH THE EVENING. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 420 PM CDT TUE APR 30 2013 STRONG DYNAMICS WILL BE MOVING INTO OUR AREA TONIGHT AND WEDNESDAY BEHIND THE COLD FRONT. EVENTUALLY...THE JET STREAM BECOMES FAVORABLY ORIENTATED PLACING OUR FORECAST AREA IN THE RIGHT QUAD ENTRANCE REGION BY VERY LATE TONIGHT...AND LASTING THROUGH WEDNESDAY. MID LEVEL FRONTOGENESIS IS EXTREMELY STRONG AND STAYS RATHER STATIONARY THROUGH THESE TWO PERIODS...EXCEPT IN OUR NORTHWEST ZONES WHERE FRONTOGENESIS IS BASED HIGHER. THEREFORE PRECIPITATION IS A GOOD BET EXCEPT IN OUR EXTREME NORTHWEST CORNER...AGAIN WHERE DYNAMICS IS LACKING AS WELL AS LOW LEVEL MOISTURE. THE NAM IS THE COLDEST MODEL BOTH AT THE SURFACE AND ALOFT...WITH THE OTHER MODELS A GOOD CATEGORY WARMER. THEREFORE BELIEVE THE NAM IS A BIT TOO COOL FOR THIS EVENING. THAT SAID...WITH MANY TEMPERATURES HOVERING JUST ABOVE FREEZING ON WEDNESDAY WHERE PRECIPITATION IS FALLING...THERE CERTAINLY WILL BE A THREAT FOR SNOW...OR AT LEAST A RAIN AND SNOW MIX...ESPECIALLY WHEN PRECIPITATION RATES ARE STRONG. ONE DIFFERENCE IN THIS EVENT COMPARED WITH THE LAST COUPLE...IS THAT IT IS NOT QUITE AS UNSTABLE IN THE MID LEVELS. IT IS SOMEWHAT UNSTABLE AS IS EXPECTED FOR SPRING TIME...BUT NOT TO THE DEGREE OF OUR APRIL SYSTEMS. NOT EXPECTING A LOT OF SNOW TO ACTUALLY STICK. BUT ONE EXCEPTION COULD BE IN THE HEART OF SOUTHWEST MN WHERE TERRAIN COULD HAVE AN INFLUENCE ON ACCUMULATIONS. WENT WITH 2 TO 3 INCHES WEDNESDAY MORNING FOR THE PIPESTONE...SLAYTON AND WORTHINGTON AREAS. THIS IS KIND OF A COMPROMISE BETWEEN WHAT COULD BE A REAL QUICK 4 INCHES IN THOSE AREAS ON WEDNESDAY MORNING...OR VIRTUALLY NOTHING IF THE SNOW RATES ARE NOT STRONG ENOUGH TO OVERCOME THE WARMER GROUND. ELSEWHERE...SNOW AMOUNTS SHOULD BE LIGHT DUE TO MELTING. CONCERNING TEMPERATURES...CONSENSUS READINGS WERE DEFINITELY THE WAY TO GO FOR LOWS TONIGHT AND HIGHS ON WEDNESDAY. THE PROBLEM WITH THE RAW VALUES IS THAT THEY ARE CONTAMINATED WITH VERY COLD NAM VALUES AND WERE NOT USED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 420 PM CDT TUE APR 30 2013 MAIN FRONTAL BAND WILL HAVE SETTLED INTO EASTERN PORTIONS OF SOUTHWEST MINNESOTA TOWARD THE KSUX AREA BY EARLY EVENING. STRONG FRONTOGENESIS IN THE ENTRANCE REGION OF JET SHOULD CONTINUE TO ENHANCE PRECIPITATION ALONG THE MID LEVEL BOUNDARY...WITH SENSITIVE LAYER LOOKING TO BE AROUND THE 700-650 HPA LAYER. SOMEWHAT NEGATIVE EPV A SHORT DISTANCE ABOVE THE FRONTAL LAYER SUGGESTS POTENTIAL STRONG BANDING...BUT MAX LIFT ALSO LOOKS TO BE IN THERMAL PROFILE JUST A BIT TO THE WARM SIDE. WILL ALSO FIND A MIX POTENTIAL CONTINUING IN THE FAR SOUTHEAST IN THE EVENING. GIVEN THE MARGINAL THERMODYNAMICS...WILL TAKE EITHER A GOOD COMPONENT OF DIABATIC IMPACTS OF HEAVIER RATE OR ELEVATION TO ACCOMPLISH A DECENT ACCUMULATING SNOW. LIKELY NOT EVEN TO BE A GREAT OR LASTING ACCUMULATION ON ROADWAYS WITH AIR TEMPS ONLY A SHADE BELOW FREEZING...AND THE LATEST 2 INCH SOIL TEMPERATURE AT 59 DEGREES THIS MORNING. THE BAND WILL SETTLE GRADUALLY SOUTHEAST AS DRY AIR AT LOW LEVELS WORKS TO UNDERCUT BAND...WHICH WILL DROP DOWN AMOUNTS AS WELL. OVERALL...USED A LOT OF 3-4/1 SNOW TO LIQUID RATIOS TO ACCOUNT FOR A FRACTIONAL MELTING OF THE ACTUAL 8-9/1 RATIOS. THE RESULT OF THE SNOW FROM WEDNESDAY INTO WEDNESDAY NIGHT WILL BE A BAND OF 2 TO 4 INCHES SNOWFALL IN MUCH OF NORTHWEST IOWA AND SOUTHWEST SOUTH DAKOTA...FOCUSING ON THE MORE ELEVATED AREAS. NO HIGHLIGHTS DEEMED NECESSARY WITH LIKELIHOOD OF LESSER IMPACT WITH SNOWFALL THAN AMOUNTS MIGHT OTHERWISE SUGGEST. LINGERING SNOW IN FAR SOUTHEAST CWA LIKELY TO END FAIRLY QUICKLY ON THURSDAY MORNING...WITH DROP IN INTENSITY AND DIURNAL CYCLE ENDING WITH A MIX. DRY AIR WILL CONTINUE THROUGH THE AREA...AND PLAYED TEMPS CLOSER TO MIXING OF 925 HPA TEMPS WEST AND SOMEWHAT LESSER WITH MELTING SNOW TO THE EAST. SOUTHERN END OF THE TROUGH PROGRESSING THROUGH THE PLAINS WILL CONTINUE TO DIG AND INCREASE CURVATURE ON THURSDAY...AND SHOULD CLOSE OFF ON FRIDAY. AS A RESULT...THAT MID LEVEL BAND WHICH HAS SETTLE TO THE EAST WILL BEGIN TO WORK BACK WESTWARD...AND WILL SEE AREA OF SHOWERS BUILD BACK FROM THE EAST AS THE DAY WEARS ON...PERHAPS REACHING I-29 OR SO BY LATE DAY. FOR THE EXTENDED PERIOD /SATURDAY THROUGH TUESDAY/...THE UNFORTUNATE CIRCUMSTANCE OF WIDELY DIVERSE SOLUTIONS WITH THE UPPER LEVEL LOW CONTINUE...AND CONFIDENCE IN ANY ONE SOLUTION IS MINIMAL. CANADIAN GLOBAL AND 00Z ECMWF BY FAR THE MOST NORTHWARD TRACK TO CLOSED UPPER LOW...WITH ECMWF UNREASONABLY QUICK WITH EXIT. SEVERAL SOLUTIONS REMAIN WITH MUCH FARTHER SOUTHWARD LOCATION TO DEVELOPMENT AND MEANDERING...SLOWER...WITH AN EVENTUAL WANDER INTO THE GREAT LAKES PER GFS/ENSEMBLES. OVERALL...THE LATTER SOLUTIONS SEEM MUCH MORE REASONABLE...AND 12Z ECMWF HAS STRONGLY SHIFTED THAT WAY AFTER A MORE SUBTLE TREND TO 00Z RUN. LIKE THAT WESTWARD WRAPPING RAIN BANDS WILL CONTINUE TO PLAGUE THE AREA SATURDAY INTO AT LEAST SUNDAY...BUT DIMINISHING THROUGH THE DAY. TEMPS DO REMAIN WARM ENOUGH THROUGH THE PERIOD TO KEEP ANY NON LIQUID PHASE OUT OF THE REALM OF POSSIBILITY. NARROWED DIURNAL RANGE CLOSER TO CORE OF LOWER TO MID LEVEL THERMAL BOUNDARY/INVERTED TROUGH. CHOSE TO REMOVE SOME PRECIPITATION GOING THROUGH MONDAY AND TUESDAY WITH GREATER UNCERTAINTY TO LARGE SCALE PATTERN...AND WILL GIVE ANOTHER DAY TO START TO AGREE A BIT MORE. SINCE WEEKEND SYSTEM IS LARGELY A SOUTHERN STREAM ORIGIN...LIKELY THAT ONCE IT PULLS OUT WILL GET A RAPID RESPONSE WARMING BACK TO NEAR AND ABOVE NORMAL BY EARLY WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 1050 PM CDT TUE APR 30 2013 RAIN WILL CONTINUE TO OVERSPREAD MUCH OF THE AREA TONIGHT...WITH JUST THE NORTHWEST PORTION OF THE AREA STAYING DRY. THUS KHON SHOULD BE ABLE TO REMAIN VFR THROUGH THE PERIOD. ELEVATED SHOWERS AND THUNDERSTORMS CURRENTLY FORMING OVER PORTIONS OF NEBRASKA AND NORTHWEST IOWA. ENOUGH INSTABILITY EXISTS FOR THE POTENTIAL FOR OFF AND ON THUNDERSTORMS THROUGH MUCH OF THE NIGHT AT KSUX. FURTHER NORTH...SOME ELEVATED INSTABILITY IS NOTED AT KFSD...BUT IT IS BASED PRETTY HIGH...AND FEEL THUNDER THREAT IS A LITTLE LOWER. SO WILL NOT INCLUDE IN THE TAFS AT THIS TIME...BUT AGAIN A FEW STORMS CAN NOT BE RULED OUT TONIGHT. WITH VERY DRY LOWER LEVELS...CIGS MAY BE ABLE TO REMAIN VFR THROUGH THE NIGHT AT KSUX...WITH JUST PERIODIC VISIBILITY DROPS INTO THE MVFR RANGE IN ANY SHOWERS OR STORMS. AS THE MORE STEADY AREA OF RAIN MOVES INTO KFSD THINK CIGS EVENTUALLY GO MVFR LATER TONIGHT. OTHER CONCERN IS FOR POTENTIAL SNOW LATER TONIGHT INTO TOMORROW AS COLD AIR WORKS INTO THE AREA. CURRENT THOUGHTS ARE AT LEAST SOME WET SNOW MIXES IN AT KFSD AFTER 12Z AND KSUX AFTER 16Z. IF THESE AREAS GET UNDER A HEAVY BAND AFTER THESE TIMES...THEY COULD TURN TO ALL SNOW WITH A PERIOD OF IFR OR BRIEFLY LIFR CONDITIONS. PRECIP SHOULD LIGHTEN IN INTENSITY AT KFSD BY EARLY AFTERNOON...BUT STEADY PRECIP MAY KEEP GOING AT KSUX THROUGH THE PERIOD. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && UPDATE...08 SHORT TERM...MJF LONG TERM...CHAPMAN AVIATION...CHENARD
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SIOUX FALLS SD 1057 AM CDT TUE APR 30 2013 SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098- IAZ001>003-012>014-020>022-031-032-NEZ013-014-011200- AURORA-BEADLE-BON HOMME-BROOKINGS-BRULE-BUENA VISTA IA- CHARLES MIX-CHEROKEE IA-CLAY-CLAY IA-COTTONWOOD MN-DAKOTA NE- DAVISON-DICKINSON IA-DIXON NE-DOUGLAS-GREGORY-HANSON-HUTCHINSON- IDA IA-JACKSON MN-JERAULD-KINGSBURY-LAKE-LINCOLN-LINCOLN MN- LYON IA-LYON MN-MCCOOK-MINER-MINNEHAHA-MOODY-MURRAY MN-NOBLES MN- OBRIEN IA-OSCEOLA IA-PIPESTONE MN-PLYMOUTH IA-ROCK MN-SANBORN- SIOUX IA-TURNER-UNION-WOODBURY IA-YANKTON- 1057 AM CDT TUE APR 30 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH DAKOTA... SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND NORTHEAST NEBRASKA. .DAY ONE...TODAY AND TONIGHT FIRE DANGER... THE GRASSLAND FIRE DANGER INDEX WILL REACH THE VERY HIGH CATEGORY IN EXTREME NORTHEAST NEBRASKA...EXTENDING NORTHWESTWARD TO ALONG AND WEST OF THE JAMES RIVER VALLEY. IN THOSE AREAS...HUMIDITY VALUES WILL DROP TO 25 TO 30 PERCENT WITH NORTHWEST WINDS AVERAGING 15 TO 25 MPH. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY RAIN MAY BECOME MIXED WITH OR CHANGE TO SNOW LATE TONIGHT OR WEDNESDAY MORNING. AT THIS TIME...IT APPEARS THAT IT MAY BE TOUGH TO GET SNOW TO ACCUMULATE...AT LEAST ON THE PAVEMENT. IF TEMPERATURES CAN COOL ENOUGH...THE GREATEST CHANCE FOR SNOW ACCUMULATIONS OF A COUPLE OF INCHES WOULD BE ACROSS SOUTHWEST MINNESOTA AND EXTREME NORTHWEST IOWA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. && FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT WWW.WEATHER.GOV/SIOUXFALLS. THIS INCLUDES THE GRAPHICAL HAZARDOUS WEATHER OUTLOOK.
The national radar mosaic for the moment the first event began.
2 drought. Local standard time, as filed.
Long term dry soil conditions at the start of May improved steadily in early May with increased precipitation, and the effect of low Missouri River flows also decreased. The sensitivity of crops and water supplies to future dry weather steadily decreased.
Long term dry soil conditions at the start of May improved steadily in early May with increased precipitation, and the effect of low Missouri River flows also decreased. The sensitivity of crops and water supplies to future dry weather steadily decreased.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Nebraska in 2013Every state in 2013This day in weather historyWarnings in Nebraska, May 2013
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: 453428, 453429.