As you may be well aware…it’s been a chilly January up until now!  In fact you could say it’s been quite historic:  the average temperature for the first 15 days of the month (both highs and lows), is 19.4 degrees F.  That is more than 16 degrees colder than average for the first half of January.  If the second half of the month were just as cold as the first half, then it would end up as the 3rd coldest month ever recorded at DLS airport – behind January 1950 (19.0) and Jan. 1979 (18.5).

But the second half of this month is NOT going to be as cold as the first half, and the transition out of our current frigid pattern is going to pose a real mess come tomorrow evening and Wednesday.  More on that in a moment.

Given how long it’s been cold in the Gorge, I am actually amazed that we don’t have more ice drifting down the Columbia River.  I distinctly remember lots of ice flows during the 1996 arctic blast.  That event was perhaps 10 degrees colder than these last few days have been, but it was a shorter-lived cold stretch overall.  (And temps to our immediate east upriver, like Hermiston and the Tri-Cities, HAVE been nearly as cold as 1996 these last few days due to extra nighttime clearing.)

In spite of all this cold, only a few shallow spots of the river near Riverfront Park, showed significant ice formation, at least below The Dalles Dam.  The passageway just below the Dam Lock was also partially frozen.  Above the dam, a small section of deepwater river ice was visible along the Port of Klickitat.  But most of the surface of ‘Lake Celilo’ remains defiantly liquid.  The port is not open to the public so this is about the best shot I could get:

Weird don’t you think?  Given various historic accounts of the river freezing over completely, I’d imagine a winter like 2016-17 ought to still be cold enough for at least some drifting ice.  If not, then our climate really HAS shifted considerably over the past couple centuries, eh?

Speaking of ice…we’re gonna see a lot of it beginning tomorrow afternoon as a wet, juicy system comes in from the central Pacific.  Here is the WRF-GFS precip map for tomorrow afternoon:

That’s at least 0.50″ precip for The Dalles between Tuesday and Wednesday morning, and nearly 1.5″ for Portland!  In both places a cold easterly flow will continue as the moisture arrives.  With the shallow nature of the cold airmass that means FREEZING RAIN…and a lot of it.  This could be a crippling, destructive ice storm for Portland, Gresham, Troutdale and the western/central Gorge, and also pretty damn awful for Hood River and The Dalles.

The problem with ice is that 1″ of freezing rain on top of a roof, weighs about as much as one foot of light, fluffy snow.  And in many places there will be 1″ or more of ice falling ON TOP of a foot of snow.  So try and get your rooftops free of snow if at all possible, especially if you live west of Hood River where the ice glaze will be heaviest.  Also make preparations in case of power outages, etc.

The Portland area will probably not thaw out until either morning or midday Wednesday, when a warming south wind finally overtakes the cold east wind.  And the Gorge shortly after that as normal cold fronts begin to arrive.

AFTER WEDNESDAY….

Once again, what looked like a promising warmup is turning into a brief respite from a generally chilly pattern.  Even Portland will still be in the low 40s for highs by next weekend, which is about 5 degrees below average for late January.  That will keep snow and ice out of the Metro area for a while…but it won’t be warm enough to wipe out the cold departures for the month.

Right now long-range forecasts show temps in The Dalles slipping back down to highs 30-35, and lows 20-25, by early next week after a few days Thu-Sat where we partially thaw out.  The NCEP is liking the idea of staying brisk in the Western U.S. the first half of next week:

That means the 2nd half of January could still end up a few degrees below normal, even if it isn’t epically cold anymore.  I did a little climate data history research:  barring some flukish turn to warm in the next 10 days, this will probably end up being the coldest calendar month since January 1993 (26.4 degrees).  Believe it or not we haven’t had a month below 30 degrees, since the year 2000.  If late January is cool enough so that the full month comes out colder than 26.4 (very possible if snowcover remains east of the Cascades), then it would be the coldest month since December 1985!