Alert archive / Kansas / Mesoscale Discussions in 2003

Mesoscale Discussion 485

April 18, 200321 counties in Kansas; Pawnee County, Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2003, 2:52 PM CDT for 21 counties in Kansas; Pawnee County, Nebraska. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
Apr 18, 2003, 2:52 PM CDT (19:52 UTC)
Expired
Apr 18, 2003, 4:45 PM CDT
In force
113 min
Issued by
the Storm Prediction Center
All 22 counties

Atchison County, KS, Brown County, KS, Clay County, KS, Cloud County, KS, Coffey County, KS, Douglas County, KS, Franklin County, KS, Geary County, KS, Jackson County, KS, Jefferson County, KS, Lyon County, KS, Marshall 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, Pawnee County, NE

The radar

The Topeka radar (KTWX), 47 km from the middle of the area, began a volume at 19:53 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Topeka, KS (KTOP), launched 12:00Z, 7.9 hours before the alert went out and 96 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-pSkew-T log-p diagram, Topeka, KS at 12:00Z on 2003-04-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Topeka, KS at 12:00Z on 2003-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 182 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
839 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
182 m²/s²
0-3 km storm-relative helicity
318 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 18, 6:14 AM CDTMesoscale DiscussionSPCClay, Cloud, Dickinson, Ellsworth, Geary, Harvey and 13 more2 hr
Apr 18, 3:50 PM CDTTornado WatchSPCAnderson, Atchison, Brown, Chase, Clay, Cloud and 27 more6 hr
Apr 18, 5:15 PM CDTMesoscale DiscussionSPCAtchison, Brown, Doniphan, Jackson, Jefferson, Nemaha and 1 more90 min
Apr 18, 6:20 PM CDTSevere Thunderstorm WatchSPCAntelope, Boone, Burt, Cedar, Colfax, Cuming and 13 more6 hr

Nearby

Mesoscale Discussions in Kansas, 2003Mesoscale Discussions in Nebraska, 2003Every mesoscale discussion in 2003

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.