February 3, 2019: Polar Vortex Visits New Hampshire

It is certainly winter now in North America with the infamous Polar Vortex rotating down from the arctic to give us the coldest weather of the season.  NASA posted a neat video of the vortex as captured by weather satellites - it's worth watching the two-second clip.

Click here for video

New Hampshire didn't get the intense cold that our friends in Iowa and Michigan saw, but we had a few cold nights.  The coldest night here was Thursday into Friday morning, and there was a strange occurrence that night.  When I went to bed it was a balmy 2 degrees, and in the morning, around 6:30 it was just about zero.  But when I checked the minimum temperature recorded over night, the thermometer had recorded -11.2 degrees.  I didn't believe it.  The low usually occurs just before sunrise unless there's a weather change moving through, and that wasn't the case;  I doubted it could have warmed up ten degrees before the sun even came up.  So I went to check the data recorded at Laconia airport.  Sure enough, the overnight low there was 1 degree at 3:00 am, rising to 2 degrees at 7:00 am.  Still, my thermometer had never lied before, so I dug at little deeper.

Weather Underground (Wunderground.com) has many certified weather stations all over the country, so I thought I'd check out some closer to Lake Wicwas.  I found a station on Corliss Hill, one on Lake Winona, and one in New Hampton, just west of Lake Pemigewasset.  All three showed the same thing:  a significant drop in temperature after midnight, and then a massive increase of ten to twenty degrees in one hour!  The most extreme event was at Lake Winona which went from -18 degrees just before 7:00 am to +5 degrees at 8:00 am - an increase of 23 degrees in one hour!

I've never seen anything like that.  Perhaps geography was a factor.  Up on Corliss Hill, less than half a mile away but 200' higher in elevation, the increase occurred earlier in the morning, between 1:00 and 2:00 am.  But elevation alone doesn't explain why Laconia airport didn't see the event at all, as the airport is at the same elevation as Lake Wicwas.  Perhaps wind shading played a role.  Lake Winona, like Lake Wicwas, is located east of a steep ledge that rises several hundred feet above the lake.  At any rate, it's the most dramatic temperature change I've seen absent a strong front moving through.  Here's what the usual overnight change looks like, from Corliss Hill, Friday night into Saturday morning.

But it's been great to have a nice cold stretch after the last storm to keep the snow light and dry.  Linda decided (on the coldest day of the year) to take a trip up to the White Mountain Ledge.  Admittedly, it was a beautiful blue-sky day.

So we took the snowshoes and trekked through the fresh snow up to see the views.  We had to break the trail the whole way, some of which hadn't been broken out for at least two storms, other parts had only the most recent snow to break through.

We were shielded from the west wind by the hill, and the hard work (plus lots of layers) kept us warm.

She's not cold!

On the trip we saw a few tracks in the snow:  deer, ermine, even those from a snowshoe hare which I'm always excited to see since it doesn't happen very often.  (I couldn't get a decent photo as the tracks were in the shade of hemlock trees.)

You can barely make out the hare track in deep snow -
each track is an amazing six-foot leap from the prior track.

I did note a lack of fox and coyote tracks along the way, though we do have a fox that trots past our house every night, so they are around.  On the first day after the last storm we noted that there wasn't a single squirrel that made its way to the bird feeders, but on the second day they arrived.  There's no doubt about what is the center of attraction in our yard on a cold winter day.