2013 has been the year of weird weather cycles

By Dave

CHARLESTON, S.C. (WCIV) One thing that is sure about the weather is it's always in flux, and to a large degree unpredictable beyond about 48 hours. This has to do with the unequal distribution of the sun's radiation between the equator and the poles.{}

2013 has been no different but there has been some remarkable weather occurring, especially in the Lowcountry.

First, how is it determined that weather is somewhat askew?

Meteorologists often use a measuring stick referred to as "normal." This is where the past 30 years of a days highs, lows, precipitation, and other data are added together by category and divided by 30, yielding "normal."{}

Normal is very rarely attained from day to day, making weather forecasting a difficult task every day.

2012 was a very dry year with a rainfall deficit of 7.06 inches. Drought was a huge concern headed into the new year, and January did not offer any help.{}

In fact, it was the driest January on record with a paltry 0.35 inches of rain. That record dates back to the 1880s! With the lack of precipitation, parts of the Lowcountry fell into an extreme drought.

Good thing the calendar flipped to the next month because on the heels of the driest January ever in Charleston, the wettest February of record occurred. Nearly 10.5 inches of rain fell February 2013, a whopping 7.51 inches above the monthly 30-year average.{}

The drought continued, but the outlook was not nearly as grim.

Now March as far as precipitation goes was pretty much right on track with 4.07 inches, about one third of an inch surplus.

The wacky March weather was the cold temperatures. The mean March temperature this year was 52.9 degrees.{} It missed the top five coldest March list by less than a half of a degree.{} March this year was actually colder than January by almost 2.5 degrees.

April's temperatures made it back to where they should be, just over a half of a degree above the average.{} April's showers however certainly tried to do their part to bring May's flowers and 5.56 inches of rain fell, another surplus of 2.65 inches for the month.{} There were no monthly surges toward all time records.{}

The drought did finally come to an end, though.

So far of note in May is the amount of time it took to get a high temperature of 85 degrees or warmer. That didn't occur until May 9 when the thermometer topped off at 87.

It took over seven months to reach that plateau.

The previous occurrence was a high of 88 degrees on Oct. 7, 2012. Also from the beginning of 2012 to May 9, the temperatures hit 85 degrees or higher 16 times!

A look toward a national weather anomaly is the 2013 lack of tornadoes. It's not necessarily a bad thing, but something that has meteorologists scratching their heads. The Storm Prediction Center keeps three year averages on tornadoes and the current one for the first four months of the year is 537.{}

The final numbers have not been calculated for January through April's actual versus preliminary numbers, but it is going to be somewhere near or just under 200. That's almost 340 less tornadoes in the United States than there should be, or the lowest level in decades.

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