First off, I made mistakes with the previous post. Dated May 5, I forgot to hit the PUBLISH button until this morning. Secondly, the version that went out by email was incomplete. A drone panorama from Paul Leischow was omitted from the version I hastily put out, and the email version will not be updated to show the corrected version.
Now, on to the latest. Sean has been tracking how the weather we’re actually getting compares to the weather forecasts he bases his predictions on. You may recall that we put more trust in the seven day weather forecast than the fourteen day outlook.
This time around, that has worked out well. In the week since Sean released his first prediction, the weather was very close to what was forecast. The second week of that fourteen day outlook is now our coming week, and the new seven day forecast for it is more optimistic.
To be clear, the weather forecasts are updated all the time, and new seven and fourteen day forecasts come out every day. But because Sean does his graph on one particular day, the forecast line on the graph reflects the forecast available at that time.
Sean has revised his graph with the new information, and with more confidence.
Remember, you can click on this graph to see a larger version. You should zoom in on that to see it at it’s largest and sharpest.
If you want to refresh your memory, you can see the previous version by clicking here.
So, what’s different? The blue line is steeper. That’s good. It means that the weather forecast is better, and that means we’re likely to hit the target thaw index sooner. Sean is now saying it looks like the ice will be gone a day or two before the May long weekend, instead of just as it begins.
The horizontal yellow line represents the thaw index we think we’ll need to reach to melt all the ice on the lake.
The blue line represents our thaw index this year, based on known temperatures so far, and forecast temperatures for the future.
The red line shows how fast the cumulative temperatures can rise in a very good year. It’s based on the fastest-warming spring in our records.
The green line represents a worst-case scenario based on the weakest, coolest spring we know of.
It’s worth noting that the revised graph now shows that our weather is tracking very close to the best-case scenario, roughly paralleling it. That would give us a thaw that’s very fast. That’s about right for one that happens this late in the year.
Now the fine print.
This graph and prediction is based solely on air temperatures and an assumed thickness of ice based on the winter’s severity. It does not take into account such factors as the strength of water currents, precipitation, humidity, the UV index, tornadoes, tsunamis, or comet impacts.
This graph may pose a choking hazard to pets and small children, especially on a smartphone. Wear sunblock if reading the graph outdoors. Do not attempt to use this graph while driving or operating heavy equipment. Follow regional and local safety regulations regarding eye protection and personal safety equipment. Always unplug the graph before putting your hands near the moving parts.