Friday, January 26, 2018

Colder, But What About Moisture?

There are signs our January thaw is coming to an end and it's perfect timing as we begin February.  You have probably heard all the rumors around social media about the coming cold.  There's little doubt it's coming.  But here are my questions: how far south and will there be moisture?

We know models have a difficult time handling the strength and southward push of low level arctic air.  While I can't be definitive, that probably answers the first question.  Now, what about moisture?  This is the time of year when we typically get more vigorous storm systems and if there's cold air in place, then anything can happen.  

There are also signs a sharp temperature contrast will set up somewhere over the mid-south and that could lead to an area of active weather.  The maps below explain and are courtesy of

The first week of February, our pattern will change and look more like it did at the end of December.  Look at the ridging in the eastern Pacific into the arctic circle.  There's the polar vortex spinning downstream over Hudson Bay.  This is a pattern conducive to delivering shots of cold air.  It might not be sustained cold, but the overall averages should be below with a pattern like this.  Again, the question is how far south the cold air will penetrate, and most of the time, it goes further south than the models predict.
The Canadian model as of February 7.  These are temperature anomalies in degrees C.  The cold air is coming down the plains and down the east slopes of the Rockies.  It meets some sort of resistance over the  Gulf States with warmer than average temperatures.  This could be a zone where it becomes active with rain, storms, and wintry weather.  It's useless to get specific at this point.  If the cold air penetrates further south, that storm track is suppressed as well.  If the colder air stays north, it would bring rain and storm chances from time to time.
GEFS total precip over the next 16 days has higher precip amounts from east Texas into the east.  THIS COULD be a sign of a more unsettled pattern taking shape and with cold air back on the playing field, it will be interesting and fun to watch unfold.

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