|Map zoomed in on station SC-PC-13 |
in southern Pickens County, SC
|Wider view of precipitation in Pickens County, SC|
|8.96 inches of rain!|
Two lessons here. First, comments are extremely valuable! The second lesson is that even with 12 to 15 other observations within a 15 mile radius, not one came even close to this rain amount. More observers would have really helped define this storm. Here is a comment from the observer (a trained meteorologist) in an email:
It really is too bad there aren't more observers because I would hazard a guess that areas in and near Pendleton, SC which is just 3 miles south of me had really heavy rain before we did. And that's where the rain seemed to be reforming, right over Pendleton on north. Then as the storm tried to diminish, the whole thing just shrank right over southeast Clemson. As it was shrinking, the intensities went way up. The lightning/thunder was incredible as well.
Case #2 is an example of a storm occurring between observers. I live in Champaign County in east-central Illinois, Despite 45 to 50 active observers in the county, not one was located under this storm. We need more observers!
|Rain shower about 3 miles NW|
By 3:30 p.m. the storm had intensified and was no doubt producing heavy rain. At it's maximum the storm was about 3 miles in diameter, and during the course of its lifetime (a little less than 2 hours) it moved a distance of only 2 miles. Winds from the surface up to 20,000 feet were only 5 to 10 knots.
|Left: Radar image a 3:37 p.m. CDT when storm was its most intense.|
Right: Radar image at 4:19 p.m.
The cell was totally dissipated by 4:30 p.m. Champaign-Urbana is at the left edge of the image.
Interstate 74 is marked by the east to west red line.
This storm moved very little, so unless it was sitting over rain gauges when it developed it's unlikely any nearby gauges would have measured much, if any rainfall. What about our CoCoRaHS observers? Here is an image of the radar estimate rainfall with this cell, plotted with the location of the active CoCoRaHS observers.
So how much rain? We have observers to the east, observers to the west, observers to the north, and observers to the south, but not one where that cell developed and died out! According to radar, someone's corn and soybeans may have received a nice 1.00 to 1.70 inches of rain. But, we'll never know for sure.
We can never have too many observers!