July-Aug-Milkshake-170x65
Jack’s

More January Ups and Downs

Posted on: 8:48 pm, January 21, 2013, by , updated on: 06:33pm, January 21, 2013

It has been a rough roller coaster of a January so far! Technically, Huntsville’s average temperature (the average of highs AND lows from January 1 through January 20) is running about 4.6º F above average; Muscle Shoals is running 4.8º F above the 30-year average.

That is a little misleading, though! There are two primary reasons why we are so far above average: the warm spell week before last and a cloudy, rainy pattern that interfered with overnight low temperatures by keeping them warmer than they otherwise would have been. Here are the ups and downs so far this month compared to average (afternoon highs):

1

The Arctic air moving into the Tennessee Valley tonight will give us some of the coldest temperatures of the season so far. Tuesday promises to be a cold day, but there is another moderation coming late in the week. Temperatures rise just in time for some clouds and showers to bring more wet weather from Thursday into Friday.

Then, there is yet another blast of very cold weather headed this way for Saturday. Wind chills all day on Saturday will be in the 10s and 20s with a mostly sunny sky. That short-lived cold snap will only last through Sunday; another moderating trend should bring us some 50s and maybe even some 60s between the 25th and 30th (next week).

1

Will the roller coaster continue into February? There is good evidence for more unusually cold weather at times through the first week of the month. As you can see, the ups and downs of winter are more “normal” than the normal (average) temperature. So a statement of “colder or warmer than normal” for the month can be a little misleading as to the actual day-to-day weather. Just for fun, here’s the 500 mb height map for January 31st at midday:

Screen Shot 2013-01-21 at 6.37.20 PM

That is an operational run (18Z) of the GFS; the ensembles are in good agreement as well that once we get past the warm-up next week, you can expect another big drop in temperature around the end of January and beginning of February.

Snow? There’s nothing out there right now that screams “look at me! I’m a snowstorm!” It’s something we will watch, but I definitely wouldn’t think a chance of snow or ice is out of the question during between Jan. 30th and February 7th. There is potential for some cold weather and a southern stream disturbance marrying up for another chance of something down the road for Mississippi, Alabama, Tennessee and Georgia.

Even in that 18Z GFS run, there is a sneaky look to the upper air pattern as a system in that southern branch of the jet stream merges with the northern branch. Time will tell!

-Jason
Connect with me!
Google+: Jason Simpson
Facebook: Jason Simpson’s Fan Page
Twitter: @simpsonwhnt