Chase Log: April 18, 2002

NWS data for April 18

9:15 AM – A wind advisory had been issued for most of the 51 county Des Moines NWS Warning area. High winds are expected to continue through out the day. The SPC listed my area as a slight chance area (for severe weather). I ran the ETA model on my computer and saw what appeared to be a ripe conditions for storm development.

I had a QSO on the radio with N0YM, W0LBG and a few others who were in and out of the conversation. We were discussing the current conditions and some of the forecasts we were looking at. We were all thinking that the atmosphere was pretty ripe for severe development. Then one of the graduate student meteorologist here at Iowa State University got on the radio and started describing all reasons why it wasn’t. J W0LBG, who had accompanied me on the previous chase informed me that he had a class 6-10pm (the prime severe weather window) so he most likely would not be able to accompany me in any chase.

Monitoring the situation throughout the day it seemed that the stage was being set for a line of severe storms to build west of here. The NWS issued a tornado watch for much of Iowa and surrounding areas.

1:00PM – NA0R called for any spotters on the CARC repeater. I responded with my call sign and “can go mobile.” NA0R informed me that the NWS office in Des Moines was requesting him to come in to the office around 3:00 PM. The NWS told NA0R that there was significant possibility of a severe line to develop around the Iowa/Nebraska State line. I told him that I’d be ready and to call me as well as other spotters in the Ames area and we would be at his service.

I checked the radar and didn’t see even the slightest hint of activity. I didn’t see what the NWS was basing their forecast on, however after much examining of models I decided to look at a visible satellite picture. Sure enough there was a line of cute little puffy clouds starting to organize over the Iowa / Nebraska line.

4:00PM – I called N0YM on the CARC repeater and began to talk about the pending weather again. I looked out my window and saw a few dark based clouds just starting to form.

4:15PM – I looked out again and could see some stage development. A few clouds to the west and south were starting to go skyward.

4:20PM – More convection was pushing clouds skyward. I decided that things were definitely starting to happen and started to prepare my vehicle for the chase.  (for the record it’s a 30 minute walk to my truck from my dorm).

5:00PM – I saw a cell beginning to drop precip a few miles west of Ames so I decided to head just to the city limits to where I could have an un obstructed view of the base to tell what kind of storms were developing. I got just out of town on Lincoln Way and I could see the entire storm. I stopped and called K0DMX (Jim Snapp, NA0R, was again operating the K0DMX station at the NWS office in Des Moines) I told Jim that I was could be ready in a few minutes and that I was the only mobile station I knew of (out of our CARC club). I inquired about the cell to my west. Jim replied that the nearest cell was “way southwest.” I was confused. One minute later K0DMX called me back and said that indeed a new cell had popped up since the last radar refresh. At that time a station called K0DMX with a report, so I yielded the frequency.

The station reported hail under the storm which I was watching (centered over Boone, Iowa). I switched to the CARC repeater and called N0YM and informed him of the cell. He had been monitoring the Sheldahl repeater (linked in the SKYWARN system) so he had heard my conversation with K0DMX. N0YM agreed with me that it was time to go. He talked me into his location via the radio and I picked him up.

5:24PM – After he got in we left and went south to downtown Ames. As we drove we were discussing the options. He suggested to hit HWY 30, go east and head up I-35 to get in front of that storm. I agreed but didn’t want to go so far north that when we got to our edge of coverage we wouldn’t be able to intercept any of the storms to the south. We headed north as planned.

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A SEVERE THUNDERSTORM WARNING FOR:  N. STORY COUNTY IN CENTRAL IOWA AT 5:40 PM…NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 8 MILES NW OF AMES…OR ABOUT 36 MILES SE OF FORT DODGE…MOVING NE AT 30 MPH.

We were headed north on I-35 and together decided that we couldn’t make it far enough north fast enough to intercept this storm. We were too out of position. So we elected to turn around and head back south to get into position for the next storm.

We turned west on HWY 30 I spotted a wet downdraft in the center of the storm now centered north of Ames. N0YM reported it to K0DMX as we continued to monitor it. We got just west of Ames and turned South on X ave. (I had meant to go one more road west but made a wrong turn. (looking back I’m very glad I made that early turn).

We stopped just after crossing HWY 30 on X ave. The weather at our location was beginning to clear with a few drops of rain. We were going to watch the cell move through Ames to our north. Doing his job, my right hand man (literally on my right hand side) N0YM spotted debris in a field to our right. I looked over and saw a line of dust and debris moving in our direction very fast! It took me a second to process it but we were about to be in the center of a Rear Flank Downdraft (RFD). We were picking up modest precipitation and microscopic hail. With this dirt headed our way I threw the truck in gear and gunned it south. Our winds picked up fast and dirt started coming across the road, but the biggest area of dirt and debris was still a couple hundred yards to our right (west). The winds were at a 90° angle to our direction of travel and it was a constant job of keeping the pickup on the road. I’m not sure what the winds got up to, but I had a magnet mount CB antenna in the bed of my truck and it blew it off, sideways. I’d say over but around 60 mph maybe more.

N0YM (just a note, I almost always call Jonathan Williams and Jonathan Marvin by their call sign, cause well you see why) looked back and saw a downdraft kicking up debris throughout Ames. We were at the top of a small hill and south of the dirt and debris so I turned the truck around and pulled off the road. We reported the downdraft and severe winds to K0DMX and also the fact that we were in RFD clearing.

THE SEVERE THUNDERSTORM WARNING FOR N. STORY COUNTY UNTIL 7:00 PM HAS BEEN CANCELLED. — THE STORM THAT PROMPTED THE WARNING HAS MOVED NE OUT OF THE WARNED AREA. AT 6:44 PM…A SPOTTER REPORTED DIME SIZED HAIL IN COLO. A TORNADO WATCH REMAINS IN EFFECT UNTIL 9:00 PM THUR EVENING FOR IOWA.

We let go of that storm and decided to position our selves for the next one which was now almost due south of us. We went south on X ave and eventually 17. We stopped once to get out and try to get a grasp on the whole sky, we had the one Super cell to the northeast and the one south. and a few cells scattered in between. Another spotter, I believe KC0LGI, stopped in a white car and asked if he could follow us since he was alone. (the buddy system is always good when things that go bump in the night are involved). We had no problems with that.

For the record. I have no problem with any spotters tagging along if they are courteous enough to ask. Sometimes people will just follow you and that annoys me. I know its a free country, but I hate being followed. I also know that having official looking decals and a yellow flashing light attracts novice spotters and chasers as well as the public but I feel that the benefits of having the decals and light outweigh the cons of being a people magnet. And as long as they aren’t being obnoxious or endangering themselves I have no problem with attracting the public.  They need to know what we are doing and why we are doing it. Granted there are better times to talk about ham radio then when you’ve got a rotating wall cloud near you but I’ll take almost any courteous opportunity to say a few words for ham radio and SKYWARN. Also I’m glad to lend a hand to beginning spotters as long as they are courteous about it and ask.

We went east and then south. But we were so far out of position that it wasn’t smart to continue.

We had three choices.

  1. give up
  2. try to drive though the storm and get on the other side of it before the main cell approached.
  3. total reposition.

1) wasn’t an option. 2) was an idea but I listened to reports from the area we’d have to traverse and it was getting worse there by the minute. 3) N0YM radioed back to our friend behind us and informed him that I had decided to head north and hit thirty and head east to try and get into position ahead of it.

We did just that, well except that last part. We never got ahead of the storm, we did have a view of the base but not that great.

We asked that the Story County repeater be linked but K0DMX was too busy and requested a relay. We switched over to the CARC repeater. Two guys were having a conversation but weren’t leaving a pause for any priority traffic. It was 5 minutes or so before I could break in (it’s important to leave a pause during adverse weather so that stations can jump in and interrupt for other traffic anyways we got in and I called KB0MGQ on the CARC repeater but he wasn’t there, Jen, KB0MGQ’s fiancée (who had been nice enough to e-mail my fiancée earlier and explain that I was storm chasing and couldn’t call her) was, I handed the mic to N0YM and he arranged her to monitor the Story County repeater so that we’d have a relay to K0DMX.

We stopped chasing in Marshalltown. We had scared it off.

We were in bad positions all day and the events ended very quickly.

We turned around and rode off into the sunset…  back to Ames.

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