(WKBN) — It is no secret that skies over the Valley have been hazy the past couple of weeks. This reduced visibility is a result of wildfire smoke from fires in the Alberta, British Columbia and Saskatchewan provinces of Canada.
Despite the wet start to May, the rest of the month has featured below-average precipitation. As of today, there has only been 1.3″ of precipitation recorded at the Youngstown/Warren Regional Airport during May which is over an inch below normal.
Many of you might be wondering if the drier-than-normal conditions are related to the lack of rainfall over the Valley. Today, we will explore the relationship between clouds, rain and smoke.
The wildfire smoke is back over the area today as you can see on the Storm Team 27 satellite image below.
The smoke has led to many beautiful pictures like the one below which was taken at the Millcreek Golf Course on Thursday, May, 18th, 2023 at sunset.
Meteorologists have long debated on whether or not wildfire smoke inhibits the formation of rain. Recent studies have found that wildfire smoke can disrupt the formation of clouds and therefore precipitation due to what is called the semi-direct aerosol effect.
This phenomenon occurs when thick wildfire smoke over a region can actually block some of the sun’s rays from hitting the ground. The result is less warmth at the surface and more warming in the mid-layers of the atmosphere which acts to reduce the vertical transport of moisture and thus reduces the capability of clouds to produce precipitation.
It should be noted that this scenario often occurs closer to the source of the wildfire where the smoke actually reduces the sunlight making it to the surface of the Earth. Thankfully, the Youngstown area is a significant distance from the wildfires, so the effect of the smoke on precipitation is minuscule at best.
Earlier, it was mentioned that there is some debate on whether wildfire smoke enhances or inhibits the formation of precipitation. Interestingly, there appears to be a scenario when precipitation can be enhanced. Wildfire smoke is comprised of small particles called aerosols. An aerosol is any particle in the atmosphere that is not a native gas or precipitation.
For example, salt from evaporated ocean water can be an aerosol and so can dust from a dust storm. Atmospheric scientists have discovered that there is a certain Goldilocks zone where the right amount of aerosols in the atmosphere can actually promote heavier precipitation.
On one side of the extreme, an atmosphere that features too few aerosols results in rain clouds that grow too quickly which either results in precipitation that does not last very long or precipitation that is not very heavy.
Conversely, an atmosphere that is too polluted with aerosols results in a situation where rain clouds cannot grow at all.
The ideal scenario for heavy precipitation is a semi-polluted atmosphere that slows down the process of rain cloud development enough such that the thunderstorm can produce precipitation for a longer period of time.
This relationship will be something to keep in mind over the Valley when there is another rain chance in the forecast!