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The coldest time of year

UPDATE:  Forgot to mention in the original post that an inside tip from Robyn Sidersky let me know that as of last night Fredericksburg has been awarded Storm Ready status by the National Weather Service.  That’s great news!!

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Climatologically speaking, that is…and it IS cold in case you haven’t noticed.  The low temperature recorded this morning at the UMW weather station was 4 degrees (F), and even now under full sunshine it’s only 17 degrees. That, coupled with a dewpoint of 1 degree, illustrates the definition of an Arctic air mass:  much colder and dryer than normal wintertime Canadian air.   I hope everyone has been heeding the advice to bundle up, bring pets inside, and double check house water pipes.  One other suggestion I would toss onto the table is to ensure you drink plenty of fluids.  This arid air matches the dryness of the desert Southwest and when it’s cold folks might not feel as thirsty as they do during the summer months.  So to minimize the risk of dehydration drink more liquids than you otherwise might feel like doing.

Now, given that the cold air is in place all that is needed for some white stuff to fall is (a) some moisture and (b) a weather system to perturb conditions enough to spit out some snow.  For a couple of days now the models have been indicating two separate possibilities for this to happen, the first of which is tonight (Wednesday night).  A moisture-starved “Alberta Clipper” will dive across our area tonight and bring a chance for what can be described as either heavy flurries or light snow during the wee hours of Thursday morning.  This system won’t tap into any moisture from the Gulf of Mexico so snow totals will be light as shown in this HPC probability graphic:

This shows a 50% chance (the light blue shading over the ‘Burg) of more than one inch of snow by Thursday morning.  The accompanying graphic – which I didn’t post – shows only a 5% chance of more than two inches of snow, so one can draw the conclusion that maybe as much as an inch of maximum accumulation will occur by tomorrow morning.  All this activity should be completed by 8 a.m. Thursday.

Then, the next disturbance swoops south out of Canada Friday for another chance of snow.  The models over the past couple of days have been trending colder conditions for this, including the upper air temperatures, so this will be an all snow event rather than a mixed precipitation bag that could have ushered in some ice.  This next clipper system looked earlier this week to have a chance at “phasing” (i.e. joining forces) with a system forecast to slide across the southern U.S. states, intensifying enough to provide a more dynamic storm, but the past few models runs have indicated that won’t occur near enough to the coast to affect the ‘Burg.   It’s still worth keeping an eye on but this HPC graphic indicates very low chances of as much as 4 inches of snow from this system even over the West Virginia mountains:

The light snow (perhaps an inch) that Fredericksburg will see from this next storm should be a mainly Friday afternoon and evening event – think rush hour impacts – with everything finished by midnight.  Again, we’ll need to keep an eye on this one for any potential changes to the forecast between now and Friday.

The weekend will be chilly with highs in the low to mid-30′s but Monday will open the door to a warmup ahead of the next cold blast that will dive southward late next week.  Meanwhile keep that cold weather gear handy!

Permalink: http://news.fredericksburg.com/weather/2013/01/23/the-coldest-time-of-year/

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