Break in the heat on the way
By Skip Rigney
This week has been one of the warmest in March on record in the Gulf South.
New Orleans International Airport, with data going back 74 years to 1947, broke records on Monday through Thursday: March 23rd, 88 degrees (old record 84, 1995); March 24th, 86 degrees (old record 84, 1994); March 25th, 89 degrees (old record 84, 2018); March 26th, 88 degrees (old record 84, 2011).
The trend was forecast to continue yesterday, with Friday’s high temperature in New Orleans predicted to hit 86 degrees, which would break the March 27th record of 85 set in 2011.
I usually highlight observations from the Mississippi Agricultural and Forestry Experiment Station in Poplarville. Those readings haven’t been available this week because of staff schedule changes related to coronavirus precautions. However, an automated station in Carriere with the Citizen Weather Observer Program recorded highs Wednesday and Thursday of 88 degrees. The historical record highs at Poplarville Experiment Station for those dates are 88 and 86.
A dome of high pressure in the middle and upper atmosphere is associated with this unusually warm air. The high pressure system started the week centered above Mexico and sprawled northward covering most of the southern U.S. from Arizona to Florida.
However, the center of the high has been shifting eastward, is now above the Gulf of Mexico, and is beginning to weaken. That will allow a weak cool front to pass through Pearl River County on Sunday. Temperatures Sunday behind that front will be a little lower, but still warmer than the seasonal average.
By Monday a stronger cool front will be heading our way from Texas. By Monday night or Tuesday morning, showers and thunderstorms are expected to move into southern Mississippi ahead of the front and south of a center of low pressure moving through north Mississippi.
It’s too early to know if some of those thunderstorms will reach severe levels. However, the look of the forecast weather map for Monday night and early Tuesday is certainly one that is sometimes associated with springtime severe weather in our area.
The showers Monday night and early Tuesday will be the last chance to make up the rainfall deficit for the month. Most locations in Pearl River County have received an inch or less this month, far below the March historical average of five and one-half inches.
By Tuesday night the cool front will be to our east, and winds from the west and north will be blowing a more seasonable air mass into the Gulf Coast region. Low temperatures Wednesday through Saturday mornings should be in the 50s for the first time in ten days. Highs each of those days are forecast to be in the 70s instead of the 80s of this past week.
Another noticeable change for the latter half of the upcoming week will be much lower humidities. Dew point temperatures, which are a good measure of how much moisture is in the air, were in the 60s most of this past week. Dew points are expected to drop into the 40s for the latter half of the week, the driest feel to the air since early March.