Here’s a link to the WBIR television broadcast yesterday (Apr 23) on thier Live at Five at Four program. I guess it could be titled “How to enjoy morel hunting three weeks too early!!”
Morel – Growth Rate
Here is another picture of a yellow morel I found in “the orchard” and posted earlier. I found it on a Tuesday afternoon and marked it with a stick. I wanted to see the growth and whether the grey would turn to yellow. Tue and Wed and nights were relatively warm (50-ish) and then a cool front came in on Thursday with heavy rain on Friday, ending in the afternoon. I returned 
on Friday afternoon and took the second picture. So, the time gap is right at 3 days with a rain. I usd my iPad for the photos and tried to get roughly the ame angle. Result? Pretty much a doubling in size and turning toward yellow. Cap is becoming more pointed. The pits are a little more “open” indicating some increase in cao girth. It seemed that most of the increase, however, was due to stem (stipe) growth. Granted, it’s not replicated, but good anecdotal material.
Yellow and Cold
I found these four jewels around a large sycamore tree along a creek early Saturday (Apr 20). It had rained 1 1/2 inches the day before stopping in the mid-afternoon. Evening temperature dropped to the low 30′s but I headed out early Saturday to beat any weekend traffic in this heavily foraged location. I measured the soil temperature and it was 34 degrees !! Based on my 
experience I would say these fruited Saturday and grew fast. They were almost translucent without a single imperfection. Probably the most beautiful morels I have ever found.
I have now picked 8 out of the small orchard, but I have found no yellows anywhere except in these two places. Some spots known to be productive have not shown any color, although I have gatherd two half frees and a handful of tulip morels.
I have been keeping notes and after tomorrow I will post a summary of the past 10 days morel fruiting and pose some ideas about what has been happening. As of now, I believe we are three weeks behind normal and I am afraid we will get an abrupt end. Hope not.