Alert archive / Kansas / Winter Weather Advisories in 2021

Winter Weather Advisory 12, NWS Topeka, KS

April 18, 202123 counties in Kansas

NWS Topeka, KS issued this winter weather advisory at Apr 18, 2021, 3:26 PM CDT for 23 counties in Kansas. It took effect at Apr 19, 2021, 10:00 PM CDT. It was in force for 12 hr.

The area

The counties it named.

The facts

Issued: Apr 18, 2021, 3:26 PM CDT (20:26 UTC)
In effect from: Apr 19, 2021, 10:00 PM CDT
Expired: Apr 20, 2021, 10:00 AM CDT
In force: 12 hr
Issued by: NWS Topeka, KS

All 23 counties

Anderson County, KS, Brown County, KS, Clay County, KS, Cloud County, KS, Coffey County, KS, Dickinson County, KS, Douglas County, KS, Franklin County, KS, Geary County, KS, Jackson County, KS, Jefferson County, KS, Lyon County, KS, Marshall County, KS, Morris County, KS, Nemaha County, KS, Osage County, KS, Ottawa County, KS, Pottawatomie County, KS, Republic County, KS, Riley County, KS, Shawnee County, KS, Wabaunsee County, KS, Washington County, KS

The radar

The Topeka radar (KTWX), 16 km from the middle of the area, began a volume at 20:30 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

Topeka, KS (KTOP), launched 12:00Z, 8.4 hours before the alert went out and 61 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: 1170 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -33 m²/s²
0-3 km storm-relative helicity: 19 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this winter weather advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Topeka, KS wrote its last area forecast discussion before this winter weather advisory went out at Apr 18, 3:15 PM CDT, 11 minutes earlier.

Area forecast discussion, Apr 18, 3:15 PM CDT, 11 minutes before

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Hazardous weather outlook, Apr 18, 9:16 AM CDT, 6 hours 10 minutes before

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The office that day

Everything else NWS Topeka, KS issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 18, 3:33 AM CDT	Freeze Watch	TOP	Anderson, Brown, Clay, Cloud, Coffey, Dickinson and 17 more	12 hr
Apr 18, 3:33 AM CDT	Freeze Watch	TOP	Anderson, Brown, Clay, Cloud, Coffey, Dickinson and 17 more	47 hr

Nearby

Winter Weather Advisories in Kansas, 2021 Every winter weather advisory in 2021

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.