Alert archive / South Dakota / Frost Advisories in 2026

Frost Advisory 6, NWS Sioux Falls, SD

May 19, 202619 counties in South Dakota; 11 counties in Iowa; 8 counties in Minnesota

NWS Sioux Falls, SD issued this frost advisory at May 19, 2026, 2:43 AM CDT for 19 counties in South Dakota; 11 counties in Iowa; 8 counties in Minnesota. It took effect at May 20, 2026, 1:00 AM CDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued: May 19, 2026, 2:43 AM CDT (07:43 UTC)
In effect from: May 20, 2026, 1:00 AM CDT
Expired: May 20, 2026, 8:00 AM CDT
In force: 7 hr
Issued by: NWS Sioux Falls, SD

All 38 counties

Buena Vista County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, Ida County, IA, Lyon County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Cottonwood County, MN, Jackson County, MN, Lincoln County, MN, Lyon County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Aurora County, SD, Bon Homme County, SD, Brule County, SD, Charles Mix County, SD, Clay County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hanson County, SD, Hutchinson County, SD, Lake County, SD, Lincoln County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 19 km from the middle of the area, began a volume at 07:45 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 7.7 hours before the alert went out and 235 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 560 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 502 m²/s²
0-3 km storm-relative helicity: 519 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.4

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this frost advisory went out, 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 this frost advisory went out at May 18, 6:42 PM CDT, 8 hours 1 minute earlier.

Area forecast discussion, May 18, 6:42 PM CDT, 8 hours 1 minute before

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Hazardous weather outlook, May 18, 3:31 AM CDT, 23 hours 12 minutes before

Hazardous Weather Outlook
National Weather Service Sioux Falls SD
331 AM CDT Mon May 18 2026

IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097-
098-NEZ013-014-SDZ038>040-050-052>071-190845-
Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Lincoln-Murray-Cottonwood-Nobles-Jackson-
Pipestone-Rock-Dixon-Dakota-Beadle-Kingsbury-Brookings-Gregory-
Jerauld-Sanborn-Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook-
Minnehaha-Charles Mix-Douglas-Hutchinson-Turner-Bon Homme-Yankton-
Union-
331 AM CDT Mon May 18 2026

This Hazardous Weather Outlook is for northwest Iowa, west central
Iowa, southwest Minnesota, northeast Nebraska, central South
Dakota, east central South Dakota, south central South Dakota and
southeast South Dakota.

.DAY ONE...Today and tonight.

Scattered showers and isolated thunderstorms return to the area this
afternoon through tonight. A few strong to severe storms are possible
along and southeast of a line from Wayne to Sheldon to Windom. If
strong storms develop, ping pong ball sized hail and 60 mph wind
gusts are the main threats. However, locally heavy rainfall and a
tornado are possible.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Chances for showers and thunderstorms return Thursday through
Friday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 19, 2:43 AM CDT	Freeze Warning	FSD	Beadle, Brookings, Jerauld, Kingsbury, Sanborn	29 hr

Nearby

Frost Advisories in South Dakota, 2026 Frost Advisories in Iowa, 2026 Frost Advisories in Minnesota, 2026 Every frost advisory in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.