Yesterday we had a high temp of 88° and our low is 66° this morning. Our last measurable rain was on May 28th (these are Otsego/Plainwell stats).
Below is a graphic of our departure from normal for precipitation this year. Most of the state is 4 to 6 inches below normal.
The following is an article from Climate Action written ten years ago. The article explains why we can have hotter days during periods of drought.
For the first time, a group of scientists has assessed the global connection between soil moisture and heatwaves. They have shown conclusively that precipitation deficits increase the likelihood of hot days, which may help assess heat risks in areas of the world.
The general trend is that if there is low precipitation in the spring, there is more likely to be a hot period in the summer. Water levels in the soil are essential because moist air prevents the atmosphere from heating up as quickly as dry air. Water has a high specific heat capacity, meaning it takes more energy to heat it than it takes to heat dry air. Once the moisture has gone from the soil, however, the temperature will rise considerably.
The study showed that this was most prevalent in the Americas, Europe, Australia, China and Japan. Not only this, but it also showed that the phenomenon has most of its impact during the most extreme temperatures. The probability of these heatwaves occurring doubles in some regions after precipitation deficits.
“We knew that in some regions soil moisture greatly affected the number of hot days, because we had shown this in other studies; for example, in southern Europe. However, we did not expect this to be the case in so many regions,” says Sonia Seneviratne, who co-authored the study at ETH Zurich.
There are exceptions to this trend, however, with the author citing the Swiss summer of 2011, where a dry spring was followed by a wet July and cool August. The increased likelihood of heatwaves is a probability calculation, not a weather forecast, so whilst meteorologists can use this information to improve forecasts, on its own, it can only show a probability of heatwaves increasing.
There is little chance of rain today, we don’t have the humidity or lift mechanisms in place to fire up storms. Chances tonight through Friday as our humidity rises which may increase the likelihood of popup storms – something we haven’t seen in quite a while. Gulf moisture will be feeding into the area by tonight so hopefully, we can have chances of much-needed rain over the next several days.
- Wild Fire Danger Today; hot, dry, breezy Today will be the last of our string of mostly sunny and warm days. Today is likely to be the hottest day of the year so far. It will be breezy yet too, so given how dry it has been, the risk for rapidly spreading wild fires remains for one more day. We have an upper low that has been over Texas for most of this past week. The system is now getting sheared out of Texas by a fairly strong Pacific system this is moving on shore of our west coast today. The system being lifted out in the short term increases out mid and upper level heights and this in turn increase our thickness values. The increased ridging over us will keep today dry. The subsidence from the building ridge over us will keep result in our highest, daily high temperature of the year, to date. Many location inland of Lake Michigan should have highs in the lower 90s today. Helping the cause for this will be deeper mixing caused by the approching system. - Daily Convection into Friday, locally heavy rain possible The upper low gets close enough tonight to surge in deep moisture. The precipitable water values increase from under and inch this afternoon to nearly 1.8 inches by midnight tonight. This is a result of that upper low heading this way. This leads to a narrow band of rapidly increasing precipitable water values heading northeast into Southwest Lower Michigan by evening. Typically there is a band of showers (thunderstorms) moving along with this feature. Just about all of our high- resolution models agree with this idea too. Model sounding become nearly saturated to 300 mb by midnight, over our area. So do not be surprised by a brief period of showers this evening as this moisture surge area moves into our area from southwest this evening. Once the upper low gets into this area it will get stall here for most of the week, as it gets sandwiched between the upper ridge to the east, the polar jet to the north and developing western trough. It seems likely areas near and east of US-131 will see showers and thunderstorms Monday, mostly in the afternoon. The HRRR is showing band of 1.5 inches of rain in 3 hours at that time. Given the weak wind field in place at that time and how wet the air is, that would actually make sense. The lake breeze convergence boundary could be a focus for that convection Monday, Tuesday and Wednesday. There is not enough shear for severe storms but there is enough water in the air for locally heavy rainfall. This would seem to be our focus this week, figuring out where the locally heavy rainfall will actually be. It had for awhile looked like this system would be gone by Thursday but not it does not look like that now. Seems we need a lead shortwave from that developing western system to shear this system out of the area. That seems to now be in the Friday time frame. Thus expect a similar weather pattern most of this week, afternoon and evening convection, warm and humid otherwise. - Weekend could be wet or dry Well then what? The ECMWF yesterday had what we through was an odd solution in that it took that lead wave and really deepened it. By early in the following week it had a 557 dm 500 mb height, closed upper low over Detroit by Tuesday of the following week. Wow, that would be cold and wet for sure. Now through, we have that lead wave coming through this weekend. The question becomes how this plays out. It would seem we would get some showers when it comes through during the weekend of the 12th. Timing is questionable through. Once it comes through, how much does it develop and where does it develop, if it does? So, if it focus east of there, we are hot and dusty through a good part of the following week. If on the other hand it is not quiet so far east, we could be cool and wet. It`s to early to say how this will really play out.