Storm Chase Report By WeatherMatrix Founder Jesse Ferrell

The local storm chase(s) on August 19, 2001 were some of the most successful in my career, all told, and the storms that day were better than any since June 2, 1998 here in central Pennsylvania, home of WeatherMatrix HeadQuarters.

This chase was successful for several reasons, which I have outlined at the bottom of this summary.

STORM LINKS

• Local Radar Animation Of Event (R1, V1)
• Greg's Archive: Warnings, Radar, Surface, Soundings, Etc. For This Event
• Lee Grenci's Article Regarding this storm (published in WeatherWise Mag)
• Local Newspaper Articles:
  • Front Page Scan
  • A7 Cnt'd Scan / Grange Fair Damage
  • Text: Storm Wreaks Havoc On County
  • Text: Car Swamped, Family Scrambles To Safety

THE CHASE

AREA COVERED: BLUE=TOWARDS / GREEN=BACK

The day started out with a Slight Risk, which we had had many times this summer and had all amounted to almost nothing. But NWS seemed excited in their local discussions (even on the night before) and this excitement expanded to the Pennsylvania Storm Chasers list. Although SPC only had us in a Slight Risk, they did have us in the 5% Tornado range as late as 13Z (they later cut this down to 2% at 16Z) or western PA anyway, and this solidified my plans to chase that day.

THE SUPERCELL

I talked to a few of the guys on the PA-Chase List then decided to leave at a little after 3pm (radar). I was headed towards Philipsburg, where I thought the developing supercell was heading. The expected ST Watch was issued on my way there. But by the time I got to the Snappys at I-99, one of the guys told me to sit tight there. The storms had been moving northeast but this one at least was taking an easterly track. A ST warning is issued for the storm I am about to intercept (WUUS51 KCTP 191955).

Well, of course I went a little further, to just outside the 453 exit of I-99 north of Tyrone, and accidentally ended up core-punching from around 4 to 4:30pm (see radar animation)(pic 1). But I did see the wall cloud first, couldn't tell if it was rotating at the time, and turned out the video camera failed to record the whole thing so I couldn't watch the tape afterwards. It became rain-wrapped within minutes anyway. Rain was VERY heavy and I had one lightning strike CG about 500 feet away.

At around 4:20, the hail started, pea sized at first, then a few dimes, so I called NWS and they put it in the LSR (0420 PM TYRONE). Another ST warning is issued for the storm (WUUS51 KCTP 192020).

Meanwhile one of the other guys is observing a rotating wall cloud just east of me going up 45. You can see some rotation in the storm at at least 4:20, see Greg's Archive for other times. A MESO at 4:09 and 3-D Correlated Shear (with 2.25" hail, which was a little over I think) was called at 4:14 by the KUNV SIT.

I turn around at the 453, then traffic slows to a crawl because there is road flooding - mud and rocks are washed out into the interstate, snarling traffic (pics 4 & 3 & accidental candid shot 5 :)). A third ST warning for the storm goes out (WUUS51 KCTP 192044).

4:00 - 4:30 PM I-99 Near Tyrone, PA
4:15PM Near 453 Exit On I-99	4:30PM Road Debris On I-99	4:30PM Road Debris On I-99	4:30PM Candid Shot!

I continue to drive on 220 northeastward, thinking perhaps I can meet the storm again in Bellefonte or out on I-80. The storm is looking beautiful on the Vis Satellite. I see a rainbow which actually ends in the field next to me. I took some video of this but you can't see it very well in the captures. I also took some 35mm pictures of it while driving, which may or may not come out but if they do I will post them here.

At 5:09Z The storm is looming large on the radar (the dot for State College there is actually the airport, the storm is directly over town on that shot). I drive back into the side of it again and experience very heavy rain. At that time (around 5:30pm), 1" hail is being reported at WeatherMatrix HQ (see LSR (0532 PM LEMONT) and my weather station is recording a 35mph gust and some strange pressure fluctuations after seeing the temperature drop 15 degrees in as many minutes. The "right-turner" storm is heading directly east through town! About this time multiple trees are down on Branch Road between Lemont and Hills Plaza (which will later give me trouble coming home) but these are never reported to the NWS and hence get left out of the LSR. The weather station recorded a total of 1.35" of rain with this storm, with 1" of it falling in 15 minutes.

Weather Station Graphs & Lightning Data From Supercell Storm @ WeatherMatrix HQ
Temperature & Pressure	Rain & Lightning Counts	Total strokes: 59,435 Total strong strokes: 219 Peak stroke count: 509 at 6:33:31 PM Peak strong stroke count: 9 at 6:37:55 PM More Details... Daily Graph Below Links To Last Of Day

I stop in Bellefonte briefly to check the radar on the PDA and see that the storm is moving directly east and I won't be able to catch it on I-80, so, what with the reports of hail and wind near home, I head back towards State College.

The storm continued to the east, wreaking havoc at the fairgrounds (see radar from about that time). Another 5 or so ST warnings were issued before it got out of the county.

As the scanner reports "cars floating down the road at Clark Motors" I experience extremely heavy rain about halfway home on the Benner Pike (26). I drive past HQ directly to the Clark Motors area, which is a flat area of Route 26 (College Ave) that I am told by locals has been known to flood in heavy rains.

When I get there (see pictures below), 5 lanes are under water and traffic is only passing through the rightmost lane. Muddy water several feet deep is rushing over and under Route 26. These pictures were taken before the Police and local newspaper arrived to take pictures (see front page newspaper scan).

5:30PM Flooding From Supercell On College Avenue (Route 26) Near Clark Motors, State College
Fast Moving Waters!	4 Out Of 5 Lanes Closed	5:30PM Flooding On College Ave.	Water Overtakes Poles & Signs
Businesses Threatened	Water Flows OVER As Well As Under The Road	Closeup Of Raging Waters	Flood Waters Flow In & Out Of This Business
Traffic Attempts To Get Through Before Police Arrive	Wide Angel View: Clark Motors	People Inspect The Damage	People Inspect The Damage

I took some 35mm pictures and I'll put them up here when I get them on CD-ROM. I guess this is the report from the LSR (0700 PM STATE COLLEGE) but that seems about an hour too late.

THE BOW ECHO & SQUALL LINE

I take a look at the radar, and isn't a bow echo & squall line line headed straight my way, so I return to HQ, check in briefly with the wife and kid, then take the tripod and go a couple streets up from HQ where I have a good western view. A ST warning (WGUS71 KCTP 192201) is issued as the storms enter the county.

6:30PM Bow Echo Squall Line - Near WeatherMatrix HQ, State College
Left Side Of Squall Line	Middle Of Squall Line	Lightning Strike	Lightning Strike
Winds Increase To 30Mph	Heavy Rain, 30Mph Winds Hit	Squall Line On PDA	Debris On Struble Road

The storm comes in quick, and the gust front is a beauty (see pictures above). Rolling dark clouds taking up half of the horizon. The wind hits, above 30mph which makes the car shake, then the heavy rain hits with lightning and the winds are gusty. The storm is bowing out just to the south of me (see Radar.) In fact this storm rates higher for lightning than the first (both can be seen as spikes on the weather station lightning graph above).

A quick check of the PDA Radar indicates I'm almost through and will suffer through back rain for an hour or more, so I decide to head back down to Clark Motors to see if the additional rain made the flooding there worse. (A flood warning (WGUS51 KCTP 192229) was issued in advance of the storm because flooding from the supercell was still occuring. Rock and dirt debris covers Struble Road as I go back down to Route 26.

Clark Motors is fine, but I see that Branch road is closed so I go down University Drive to see if I can get into it from the other side. This is a negatory because there are too many trees down on Branch Rd. and the police have it blocked off. So I turn around.

At the bottom of the Easterly/Westerly parkway hill on Univ. drive I see two towtrucks and wonder what they are up to. The next day in the paper I will read that one of them at least was rescuing a woman whose car got stuck in high water on the road.

6:30PM University Drive & College Avenue
Tow Trucks That Had Rescued Underwater Car	University Park Washed Out Near Burger King	Double Rainbow At Univ. & 26

University Drive is washed out and/or has debris in places and there is a 6" diameter tree down across from Burger King (moving video didn't capture it). When I get back off of Univ. Drive and back onto Route 26 to go home, what do I see but a very bright (even shows up on the video captures!) double rainbow. I took some 35mm of this as well but it was on a new roll so don't look for those to appear on here either. Turned out that WeatherMatrix Webcam #1 was capturing the rainbow at the same time back at HQ.

CHASE SUCCESS! BUT WHY?

This chase was a very successful one for me, probably the best since the 5/29, 5/31, 6/2 outbreak of 1998. This was because of a number of reasons. Sure I didn't see a tornado, but I saw the first hail on a chase in PA, two rainbows, a wall cloud, major flooding, and trees down. For Central PA, you can't beat that. Contributing factors:

• 1. We had a decent severe weather day with both a supercell and a bow echo passing over WeatherMatrix HQ and surrounding areas. Supercells are very rare in Central PA, in fact I had only seen one or two days in the past four years. Bow echos / squall lines are more common, but still you only get a couple of these per year. To have both on the same day in the same place is a rare treat.
• 2. It was Sunday - I had no work or any plans to get in the way
• 3. It was Sunday - there was no traffic, it's impossible to get out of town at 5pm on a weekday and that's always when the storms come :)
• 4. I spent enough time getting my equipment together BEFORE the chase, the weatherradio, lightning detector, etc, and setting up the radio scanner which proved invaluable in leading me to damage areas and getting live storm reports. I tested out the hands-free cell phone set ($15 on clearance at Wal-Mart) which proved to work VERY well as I could take and make calls the whole time, getting status and weather updates from other chasers. The SAME weather-radio had new batteries and actually went off for most of the warnings & watches despite bad reception.
• 5. I brought along the mobile Internet access for the first time. If you've never tried this, it is a GODSEND. Chasing in Pennsylvania is hard because of bad sky visibility, bad roads, mountains that you can't get around, and lack of internet access on the road. You get an hour out and you have no idea what's going on and there's no way to get radar data except to call NWS or someone and have them try to describe the storms to you every 5 minutes. I had color radars on my PDA every 5 minutes for the entire chase. The wireless coverage area of the service fades in NW PA which I was a little worried about but I ended up never getting out of the county anyway (see above).