BIRMINGHAM, Ala. (WIAT) — When looking at a complex forecast, often it can be beneficial for a forecaster to look at analogs, or times when the pattern looked similar to the way we’re forecasting it to look.
One of the tools we use to look at analogs is the Cooperative Institute for Precipitation Systems analog guidance. CIPS analog guidance looks at the forecast data from a model, then compares it to observed weather patterns we’ve seen in the past, then spits out a list of dates the forecast pattern looked most similar to the past. This can be useful to relate our forecast to a past weather event, to get a better idea of what a pattern is capable of doing.
As we head into Friday, we’ve seen hints from forecast models of wintry weather in Alabama. The CIPS analogs are spitting out some interesting dates too.
The best analog for Friday is January 28, 2014; Not a day many Alabamians will forget. The analog score, over 12.6, is also indicative it’s a good analog. Scores above 11 are good, and above 12 are quite good. There are distinct similarities between the way our pattern looked then, and how it will look Friday, starting with the jet stream.
The upper-level jet stream will be in a very similar position to the “Snowmageddon” day in 2014. Just like 2014, a strong cold front will have passed the day before, ushering in some colder air. We’ll also have some drier air in place.
Unlike 2014, it won’t get as cold as it did that day. We started out Jan. 28, 2014 in the 20s, dropping into the teens that evening. We’ll be in the 20s Friday morning, warming up into the upper 30s Friday afternoon. That’s still cold enough for snow, though. Our biggest difference, and the reason we’ve got a dry forecast instead of a wintry one, is moisture.
Both January 28, 2014 and Friday had dry air as a complicator in the forecast. That dry air near the surface back in 2014 was supposed to help evaporate snow in Central Alabama, leaving us with little more than a few flurries. That didn’t happen as moisture moved in from the south more quickly than forecast, and heavy snow aloft helped moisten the atmosphere and keep things cold leading to heavy snow. The opposite is expected this Friday. Instead of moisture moving in, it’s leaving fast behind the strong cold front.
That, and a lack of strong rising air, should put the nail in the coffin of any snow chances for us this round. Expect cold and dry weather Friday, with our next rain chance coming Tuesday of next week.
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