April continuing March’s above-normal temps
Published 7:00 am Tuesday, April 26, 2016
This week is forecast to be our warmest since last October. Afternoon highs are predicted to be in the low-to-mid 80s each day. Lows will be in the middle to upper 60s.
These temperatures, especially the lows, will be several degrees above average, continuing the trend of a warmer-than-average April.
This follows on the heels of above-average temperatures in March in south Mississippi.
South Mississippians weren’t alone in March. According to the National Oceanic and Atmospheric Administration’s National Center for Environmental Information (NOAA NCEI), March was warmer than average across the entire lower 48 states and Alaska. In fact, according to NCEI, March 2016 was warmer than average across most of the earth. (http://www.ncdc.noaa.gov/sotc/global/201603)
To have monthly anomalies so widespread is very unusual. It’s common for one part of the country to be warmer than normal, while another section of the nation is colder than average.
For example, a southward dip in the position of the jet stream over the western half of the country is often accompanied by a northward bulge in the jet stream over the eastern half of the country. Often such a pattern will persist for several weeks or longer, causing the average temperatures for that month to be below normal in the west and above average in the east.
However, last month the entire United States ended up warmer than average.
The NCEI divides the country into 357 “climate divisions.” Pearl River County is in a climate division comprised of the six southernmost counties in Mississippi.
In every one of the 357 divisions in the lower 48 states and Alaska, March 2016 was one of the top-third warmest months of March on record. Deke Arndt, Chief of the Climate Monitoring Branch at NCEI, noted in a recent article that this is the only time this has happened since 1930, which is the earliest that such nationwide statistics are available.
Precipitation for the nation was much more of a mixed bag in March.
Parts of the Southwest and Appalachia had below-average rainfall. Meanwhile, our area was wetter than average, and other parts of Mississippi, Louisiana, and Arkansas had their wettest March on record.
As for this week, the Bermuda High pressure system, a dominant player during the summer, makes an early appearance as it noses into the Gulf.
The onshore flow will bring in warm air and increasing humidity.
An upper level trough of low pressure passing to our north will provide enough lift to kick up widely scattered thundershowers on Wednesday and Thursday.
A stronger upper level trough of low pressure is predicted to move eastward out of the southern Plains into the Mississippi Valley late in the weekend.
That disturbance will likely give us a good chance of showers and thunderstorms. It is difficult for the numerical models to accurately predict the timing of the rain this far in advance, but at this time, most of the models predict our best chance of rain will be Saturday night and Sunday.
If you have outdoor plans on Sunday, you may want to check the forecasts as the week progresses.
By Skip Rigney