The ground is wet for sure and soil moisture values will increase the next few days with an unsettled weather pattern. From this mornings NWS discussion:
- Showery activity will continue today and transition to low clouds and drizzle tonight into early Wednesday. - Showers and thunderstorms are expected north of I-96 and west of US-131 Wednesday afternoon and evening with small hail and locally heavy rain possible. - Another round of showers and storms is expected Thursday afternoon and evening with locally heavy rainfall as the main threat. - A marginal threat for excessive rainfall exists west of US-131 from Wednesday afternoon to Thursday due to repeated rounds of showers and storms over increasingly saturated ground.
Soil moisture is important to forecasting. When the soil is saturated, evaporation from the earth’s surface and transpiration from trees will modify the weather. During the day, the evaporation and transpiration cause the air to be cooler than it otherwise would have been BUT also adds moisture to the air.
In warm climates, the added moisture can more than offset the cooling from evaporation when it comes to how comfortable the air feels. A temperature of 95 with a dewpoint of 75 feels much more uncomfortable than a temperature of 100 with a dewpoint of 50. Of course the terminology of uncomfortable is different from person to person. For me anything over 75° is uncomfortable regardless of the humidity levels.
Saturated soils increase the likelihood for dew and frost, especially on clear nights with light wind. The soil moisture increases the dewpoint, which in turn causes the air above the surface to be closer to saturation. Soil moisture is also important to instability.
The addition of moisture from evaporation and transpiration add moisture to the air which can increase the likelihood of rain when a front or another trigger mechanism moves through. An extended period of dry weather will cause soil moisture values to be below normal. This has an effect of reducing rainfall (less evapotranspiration results in less moisture for fronts to lift and less thermodynamic instability).
There has been a debate whether our summer will be cool or hot this year, or just right. Below are the anomaly graphics from the CPC for this summer which would make one think we would have a cooler and wetter season. I would take this with a grain of salt as weather dynamics tend to change day to day and week to week.
There is a lot of physics and math (algebra, calculus and statistics) which goes into the study of meteorology along with geography, knowing the effect of the terrains effect on the weather. I won’t get into the math part because even though I am still studying much of it is beyond my understanding. I used a lot of statistical math in my job before I retired however the calculus gave me a headache and brought out my ignorance of the symbology of those things.
I hope this series is helpful for all of you – when I am done I will create a page with a downloadable PDF book covering the whole thing….
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