MAY 16-17, 1997

YANKTON, SD CHASE
Carson Eads and Tim Marshall

8:06p 164 FLOWER MOUND- Leaving tonight for Wichita. We are heading up into Kansas tonight since SPC has a moderate risk out for northeast Kansas, southwest Iowa and southeast Nebraska tomorrow. There are a lot of negatives with it. First, we have northwest flow aloft which I do not like, moisture is uncoupled from the system, models are showing a low forming in eastern Colorado with a vort max hitting there about 00z. Thus, the upper air is out of phase with the surface. A line of severe thunderstorms occurred today in central Kansas and should leave an outflow boundary there for tomorrow. I-35 N.

10:36 353 OKLAHOMA CITY- I-35 N.

1:00a 533 WICHITA - Stayed at Super 8. 5 hours, 369 miles

9:25a 533 WICHITA- Heading N on I-135. Heading into eastern Nebraska. The moderate risk forecasted last night for today has shifted about 500 miles due north to eastern South Dakota and western Minnesota. So, we either go home this morning or chase today. We should not have left last night. An Alberta clipper is progged to dive southeastward into eastern South Dakota late. Front is progged to stall in central Kansas by tomorrow. Lots of negatives today.

11:20 633 SALINA - Stopped. Met Ian Wittmeyer. I 135N.

12:08 689 CONCORDIA - ESE winds at 10.

12:38 723 Nebraska Line. ACCAS N and overhead. CI horizon NE-N-NW. Light SE wind.

1:33 786 YORK - Virga overhead. Rt. 81 N. SE winds at 10. Build-ups on ACCAS.

2:27 844 COLUMBUS - Mid-level overcast with virga. SE winds at 10. Rt. 81 N.

3:14 893 NORFOLK - Stopped for data. We'll proceed north a ways further.

4:23 931 Cb NW. Anvil pointing SE. Line of cumulus N through E. Line of towers N of the Cb.

4:45 958 YANKTON - First time chasing in South Dakota. Stopped.

5:56 959 YANKTON - Looked at data. Dewpoints are suffering here. Cb orphaned out. Winds are calm. Multi-cell stuff is blowing up in central Kansas.

6:20 964 YANKTON - 2 mushy Cb's N-NW. Moisture is a real problem. Abort. Norfolks ob is 85/47 27% humidity. We are leaving town. Rt. 50 E.

6:49 999 I-29 S. Lots of cirrus and virga. Tower NE.

7:08 024 SIOUX CITY, IA - SW winds 15. Cb N and NW, still mushy. Stopped to look at the Weather Channel. There is a Tornado Watch issued for eastern South Dakota and North Dakota as well as western Minnesota. There is an incredible supercell with hook on it moving south in southeastern NORTH Dakota. There are three severe thunderstorm boxes through Kansas and NE.

8:18 098 2 Cb's SW. Long anvil extends out to the southeast.

8:21 Broad dome on Cb with anvil backshear.

8:32 Dome has collapsed on Cb leaving splashing CI remnant.

8:45 132 COUNCIL BLUFFS, IA - I 29 S.

10:26 236 MOUND CITY - Moderate rain. Lightning S. Storms formed along old front.

10:55 272 ST. JOSEPH, MO - I 29 S. Flash rates have gone downhill.

11:26 310 PLATTE CITY, MO - Turned east on Rt. 92.

11:39 321 SMITHVILLE , MO- Staying at Super 8 for the night. Just after we got into the motel, the storm front hit bringing heavy rain and lightning.

SUMMARY: Shouldn't have chased. 1157 miles, 19.3 hours, TRW