Evaporation of Recent Rain to Trigger Higher Humidity and ... - FOX Carolina 21

Evaporation of Recent Rain to Trigger Higher Humidity and More Storms

Overnight Forecast Fail Equation:  This was HPC's 1am to 7am forecast for our area: http://www.hpc.ncep.noaa.gov/qpf/fill_91ewbg.gif =  cliffhanger or oldiebutgoodie

Let's Discuss:  Based on the recent pattern of lakes, ponds and moats being created in our yards after sunset here lately, it wasn't much of a surprise that last night was yet another night of absolute downpours for portions of the following counties: Cherokee, Polk, Rutherford, Spartanburg, Greenville, Laurens, Anderson, Abbeville and lastly Greenwood.  As Ty wrote on a comment after Kendra's post yesterday, "WOW, we are getting rocked in Cowpens again." 

It's sort of strange to see these thunderstorm complexes develop and sustain themselves like they have after the sun has gone down, especially on so many recent nights.  But, it's not completely unusual and, as many of you know, this sort of thing has happened around here before.  Kendra has been having to stay late many times during the last week or so which hasn't been all that fun I'm sure!

A cause and effect to look for during the next month or so is how our humidity levels are impacted from recent rains (high levels of moisture) being evaporated into the immediate boundary layer near the ground - where we deal with the haze and humidity every day.  This daily process of evaporated soil moisture leading to higher dewpoints (high humidity) goes hand-in-hand with triggering more frequent scattered storms for us.  It's important to realize that this is the exact opposite of what happened back in the summers of '07 and '08 when our extreme drought perpetuated more drought conditions.  The key to that pattern was very little surface moisture being available for evaporation each summer day.  Each day, hardly any of the sun's energy went into evaporating soil moisture due to such a slim amount in the soil.  Instead, almost all of the sun's energy went into baking dry soil and WE BAKED!  What we dealt with then were temperatures which soared into the 100s for many consecutive days, although with relatively low dewpoints or humidity due to evaporation being a non-factor. 

Again, due to the evaporation of recent high soil moisture, we should look for higher humidity  and more scattered storms in late May and early June, although probably not as many gully-washers as we have seen in recent days.  Also, I realize it isn't a shock to know that we will deal with high humidity, I just wanted to point out that these recent storms may lead to higher levels in the immediate future.

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Today:  That humidity will be felt today.  Highs will reach the middle 80s in the Upstate with afternoon temperatures near 80 for Western NC towns.  Also, we'll have a mix of sun and clouds with a few afternoon storms.  Overall though, our overnight storm chances will go down from previous nights, but we can't completely rule out the slim possibility of a cluster developing after sunset.

Friday & Saturday:  Just as Kendra mentioned in her post yesterday, a change in wind direction will provide some slightly drier air, more sunshine and less chance for storm development in the coming days.  This will just be temporary though as we'll see a resurgence in humidity by early next week and rain/storm chances will follow close behind.  I seriously doubt next week will be as soggy as what we have dealt with during the past week, but the humidity will be make things soggy for you!

Where's the Heat Wave?:  After looking back through our recent climate records from over at GSP Airport, the highest temperature recorded at GSP so far this spring was on April 2nd at 88°.  That's right... we have yet to reach higher than that since and we still haven't hit 90° at GSP for May (yet at least).  This is surprising considering the kind of heat we are used to around here in May! 

It doesn't look like the next seven days will offer any 90°+ sort of heat... in fact, we may not get above 85°.

Interesting Number:  The average high temperature so far this month (through the first 16 days of May) at GSP is 79.93°.

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