By Skip Rigney

Some weeks the weather is so tranquil that many of us hardly give it a thought. Not this past week, as three significant weather events affected us. They were hard to ignore, even for folks who seldom notice the weather.

The most recent was the passage of the strongest cold front so far this fall. Temperatures dropped from the mid-70s to mid-50s in three hours around sunrise Thursday morning. Brisk north winds blew in cold air all day Thursday giving us our coolest afternoon since April.

Friday morning was the coldest since March as temperatures fell into the 30s with some locations flirting with freezing. Forecasters predicted similar lows for Friday night, and with calm winds expected most of the night, widespread frost is likely Saturday morning.

Cool, fair weather is expected to last the entire weekend due to a reinforcing surge of cool, dry air expected by forecasters to arrive today.

The dry spell will be a welcome respite from the rains caused by the cold front Thursday morning and a warm front on Wednesday. Rainfall across Pearl River County over those two days ranged between 1.25 and 2.50 inches based on rain gauge stations and radar estimates.

Wednesday and Thursday’s rain came less than a week after the drencher that swamped the area on Friday and Saturday, October 25 and 26. Most locations in Pearl River County received between four and seven inches of rain during those two days.

That deluge was associated with three systems converging on the Gulf South: low pressure in the upper atmosphere, a slow-moving cool front, and a Gulf low that became Tropical Storm Olga for a few hours.

The rain over the past eight days helped push October’s rainfall totals across the county into the eight to eleven inch range. That’s over double the long-term climatological average rainfall for October. Pretty impressive given that the first ten days of October in the county, and across most of the state, extended a dry streak that had begun in late August.

Not only did the low pressure system briefly known as Tropical Storm Olga contribute to the heavy rainfall across south Mississippi and southeast Louisiana in the early morning hours of Saturday October 26, post-tropical Olga also brought the highest wind speeds that many people in our area have seen in several years. According to the National Weather Service in Slidell, wind gusts of 40 to 50 mph were widespread with a few gusts as high as 70 mph reported in southeast Louisiana.

Olga was declared “no longer a tropical storm” as it moved ashore because it was becoming entangled with a frontal system.

That meant the storm was beginning to get part of its energy from temperature differences in the atmosphere and not just the warmth of the ocean’s surface. While the transition from a tropical to non-tropical low usually results in the system weakening, Olga’s winds certainly didn’t decrease until it was well to our north.

The National Weather Service in Slidell stated in its online summary of Olga, “The wind gusts were stronger than what was expected and we will be studying this system over the coming months to learn how we can better forecast any similar situations in the future.” (www.weather.gov/lix/OlgaSummary)