76 inches at Platte.
Every event with a place to put it. 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.
Three to five inches of rainfall occurred in the Platte Creek basin between August 7 and August 10, including 4.76 inches at Platte.
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 Aug 9, 9:55 PM CST, 1 hour 5 minutes earlier.
AREA FORECAST DISCUSSION National Weather Service Sioux Falls SD 1055 PM CDT Fri Aug 9 2019 .UPDATE... Issued at 948 PM CDT Fri Aug 9 2019 Convection has generally shifted south of the state line in Nebraska with only a few cells left in south central South Dakota. Lighter rain continues along and south of Hwy 30/34 east of the James River to about OTG and Slayton. The convection has shifted the boundary to the south of the area. CAMs continue to show convection along and north of I90 later tonight as LLJ increases. However, CAMs have struggled with convective evolution all evening - generally being too far north and too slow. So, at this time, expecting that as LLJ increases in the next hour or two, new convection will favor south of I-90 into Nebraska. The only exception would be in there can be a 2-4 hour break until 06-08Z for new convective initiation then the front may be able to shift back north and favor new development into east central SD. At this time, favoring a southern solution with PoPs highest in the Missouri Valley through 06Z. and lowering to 30-60% along/north of I-90 with the highest PoPs in southwestern MN. Have also decreased QPF after 06Z given lower confidence in overall rainfall across the area. As a result we have cancelled the Flood Watch along and north of I-90 but continued it south of I-90 where the threat for heavy rain continues for at least the next 2 to 4 hours. The severe threat has decreased markedly with lack of a significant lifting mechanism. The RAP is likely overdoing MLCAPE given the front is farther north in the model than observed but still expect CAPE around 1000 J/kg over much of the area with 1500 J/kg near the stateline so could see an marginal severe hail if a stronger updraft is able to develop. && .SHORT TERM...(This Evening through Tonight) Issued at 227 PM CDT Fri Aug 9 2019 A very potent severe weather setup continues to build this afternoon across central and western South Dakota. Mid-afternoon surface and satellite analysis showing well defined surface boundary just south of the Missouri River and Pierre southeast towards Chamberlain and approaching Charles Mix county. Isolated surface based convection has already started to develop in the warm sector, along with enhancement of elevated convection across northern South Dakota. This afternoon and evening: Very moist boundary layer air has advected northward south of this frontal boundary, with dew points in the lower 70s. This has allowed for the development of a a large MLCAPE reservoir approaching 2500 J/KG into the western third of the CWA. Isolated surface based convection to our west and northwest should become more numerous through the afternoon as large scale accent arrives from shortwave energy over NE Wyoming later this afternoon. Increasing winds aloft have already pushed effective shear values into the 40 to 50 knot range this afternoon, and this will continue to rise as low-level flow increases this evening. This setup will favor the development of one or more discrete supercells across central South Dakota into the early evening, with eventual cell mergers developing into bowing segments and clusters as storms turn southeast along the edge of the instability gradient and dive towards and across the James River Valley. As far as risks are concerned, soundings show slightly modest mid- level lapse rates and are absent of thick hail growth CAPE profiles, however strong shear should support lofting of hail with potential for 2.5" hail in supercells. Greatest risks this afternoon and evening will arrive from damaging winds and tornadic risks. Eventual advection of dry air in the mid-lvls of the atmosphere will result in DCAPE values approaching 1500 J/KG in the western half of the CWA. This will support wind gusts up to 80 mph in HP supercells along with bowing segments later this evening. More concerning are the significant tornadic parameters showing up this afternoon and early evening along the Missouri River Valley and west of the James River valley. Effective 0-3 SRH values are already approaching 300 M2/S2 near initial development this afternoon near Kadoka, with increasing low-level flow pushing those values towards 500 M2/S2 by early evening towards Chamberlain and Lake Andes. 0-1km shear/SRH values are also very impressive along the frontal boundary, sitting around 150-200 M2/S2 and 20 knots respectively by early evening. LCL heights also fall in the favorable category, lowering down towards 600-750 M AGL later this afternoon. Should discrete cells become anchored to the surface boundary, an extended long track tornado threat could be possible into the James River Valley. However, even smaller bowing segments could be strong enough to produce tornadoes given the environment this evening. Further east, while instability wanes towards the I-29 corridor, it's possible to have residual MCS complex slide eastward late this evening bringing a strong wind risk. It appears however that the greatest severe weather risk falls along and west of a line from Huron to just east of Mitchell towards Yankton. Heavy rain will also be a large risk this evening and overnight. Slow propagating supercells and any eventual complex will certainly have the potential for flash flooding. Additionally, as the LLJ refocused over MN and far eastern SD after midnight, a secondary area of heavy rain may develop along the Buffalo Ridge. Have issued a flood watch to cover both the large scale and flash flood potential into Saturday morning. .LONG TERM...(Saturday through Friday) Issued at 227 PM CDT Fri Aug 9 2019 Saturday-Sunday: Anticipating rain to linger over the eastern CWA behind this wave well into the morning hours. Residual cloud cover should limit temperatures and have lowered accordingly. Temperatures further south may rebound slightly towards 80 in the afternoon as surface low pressure slides east. A very pleasant day is expected on Sunday as temperatures climb back towards normal and dry conditions continue. Monday-Tuesday: A series of mid-lvl shortwaves arrive late Sunday night with one or more MCS developing off the western Plains and sliding eastward. We won't really scour out much of the moisture in the atmosphere this weekend, so the antecedent conditions ahead of these waves will be favorable for heavy rainfall. The locations and track of the rain are still slightly in doubt however. While the greatest severe weather risks with these MCS appear to stay south, we'll certainly need to monitor. Dry air moves in for Tuesday, along with slightly cooler temperatures. Wednesday-Thursday: The middle of the week again favors dry conditions, with gradual warming by Thursday and Friday of next week. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1052 PM CDT Fri Aug 9 2019 MVFR and potentially IFR stratus will attempt to develop on the back edge of the MCS. If stratus develops, could see additional storms develop in uncapped environment. Will be hard to shake the stratus on Saturday, though moisture will gradually thin through the day, possibly leading to breaks in the clouds late day. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...Flood Watch until 7 AM CDT Saturday for SDZ063>070. MN...NONE. IA...NONE. NE...NONE. && UPDATE...Schumacher SHORT TERM...Dux LONG TERM...Dux AVIATION...BT
Hazardous Weather Outlook National Weather Service Sioux Falls SD 327 PM CDT Fri Aug 9 2019 SDZ038-050-052-053-057>060-063>065-068-069-102030- Beadle-Gregory-Jerauld-Sanborn-Brule-Aurora-Davison-Hanson- Charles Mix-Douglas-Hutchinson-Bon Homme-Yankton- 327 PM CDT Fri Aug 9 2019 This Hazardous Weather Outlook is for portions of central South Dakota, east central South Dakota, south central South Dakota, and southeast South Dakota. .DAY ONE...This Afternoon and Tonight Scattered thunderstorms are expected late this afternoon and evening. Supercell thunderstorms are possible, bringing the potential for golf ball size hail, 80 mph winds, along with an increased possibility for tornadoes. The greatest storm risk will focus between 5 pm and 11 pm and focused along and west of the James River Valley. Heavy rain will accompany these storms, with the potential for localized 2 to 4 inch rainfall totals and localized flash flooding. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Scattered storms with locally heavy rainfall will be possible again on Sunday night into Monday. .SPOTTER INFORMATION STATEMENT... Spotter activation will be needed after 5 pm this evening. IAZ001-012-020-031-032-NEZ013-014-SDZ039-040-054>056-061-062-066- 067-070-071-102030- Lyon-Sioux-Plymouth-Woodbury-Ida-Dixon-Dakota-Kingsbury-Brookings- Miner-Lake-Moody-McCook-Minnehaha-Turner-Lincoln-Clay-Union- 327 PM CDT Fri Aug 9 2019 This Hazardous Weather Outlook is for portions of northwest Iowa, west central Iowa, northeast Nebraska, east central South Dakota, and southeast South Dakota. .DAY ONE...This Afternoon and Tonight Thunderstorms are expected late this evening and into the early overnight hours. While the greatest risk for severe storms will be west of the James River valley, a few strong storms could also track further east. The main risks will be strong winds to 60 mph, along with quarter size hail. Locally heavy rain will also be possible with this thunderstorm activity, with localized 1 to 3 inch rainfall totals. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Scattered storms with locally heavy rainfall will be possible again on Sunday night into Monday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. IAZ002-003-013-014-021-022-MNZ071-072-080-081-089-090-097-098- 102030- Osceola-Dickinson-O'Brien-Clay-Cherokee-Buena Vista-Lincoln-Lyon- Murray-Cottonwood-Nobles-Jackson-Pipestone-Rock- 327 PM CDT Fri Aug 9 2019 This Hazardous Weather Outlook is for portions of northwest Iowa and southwest Minnesota. .DAY ONE...This Afternoon and Tonight Scattered storms are expected late this evening and overnight. Small hail and gusty winds are possible, however the main threat will be locally heavy rainfall. Rainfall amounts over 2 inches will be possible under the most intense storms. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Scattered storms with locally heavy rainfall will be possible again on Sunday night into Monday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
713 PM CDT FRI AUG 9 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0659 PM TSTM WND GST 14 W PLATTE 43.39N 99.12W
08/09/2019 M60 MPH CHARLES MIX SD MESONET
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
901 PM CDT FRI AUG 9 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0745 PM TSTM WND GST GEDDES 43.25N 98.70W
08/09/2019 M60 MPH CHARLES MIX SD MESONET
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
944 PM CDT FRI AUG 9 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0930 PM HEAVY RAIN 4 SSW PICKSTOWN 43.01N 98.56W
08/09/2019 M2.91 INCH GREGORY SD CO-OP OBSERVER
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
952 PM CDT FRI AUG 9 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0900 PM FLASH FLOOD GREGORY 43.23N 99.43W
08/09/2019 GREGORY SD EMERGENCY MNGR
SEVERAL ROADS UNDER WATER IN AND AROUND THE
GREGORY AREA THIS EVENING.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
956 PM CDT FRI AUG 9 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0710 PM TSTM WND DMG DALLAS 43.24N 99.52W
08/09/2019 GREGORY SD EMERGENCY MNGR
A FEW TREES DOWN AROUND TOWN.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1138 PM CDT FRI AUG 9 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1105 PM NON-TSTM WND DMG 1 ESE YANKTON 42.89N 97.38W
08/09/2019 YANKTON SD TRAINED SPOTTER
TREES 12-18 INCHES IN DIAMETER DOWNED.
MULTIPLE TREE BRANCHES DOWNED.
&&The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Platte Creek near Platte (gage site PCPS2) crested 1.22 feet above flood stage on August 10, before falling back below flood stage later in the day.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Dakota in 2019Every state in 2019This day in weather historyWarnings in South Dakota, August 2019
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: 849625.