It hasn't rained (or snowed) in a week. Next week will also be dry.
Dry in Washington State. In mid-winter.
Is this the driest mid-winter period in the history of our region?
According to the National Weather Service, the last rain fell in Seattle on January 12th:
That is 13 days without precipitation for most locations in western Washington, during the middle of the winter!
Thirteen dry days.
How unusual is this for midwinter (we do this all the time during summer)?
Let's check the numbers for the Northwest wet season (November 1-February 28)
Below is a list of other periods when Seattle has had no precipitation for 13 days in mid-winter: FIVE other years (2005, 2002, 2000, 1993, and 1985).
What about times when Seattle had only a trace of precipitation over 13 days (a trace is when less than 0.01 inches fall)...something that can be done by a light mist?
Several other years are added. 2025, 1989, 1968, 1963, and 1956
Finally, considering years when only 0.01 inches of precipitation fell (a trace of rain...just enough to make a surface wet), we add 2013, 1994, 1989 (twice), 1976, 1974, 1992, and 1945.
The bottom line of this analysis?
Since 1945 (81 years), we have had 13-day dry periods (0.01 inch or less) about 20 times.
So it has happened before, roughly once every four years.
Such dry years are scattered over the period and don't appear to have an obvious increasing trend. This is not climate change.
The current dry period is expected to end, as indicated by the predicted precipitation through February 5 (see below).
So enjoy the sun while you can.
As a skier, this period has truly sucked. Other than the one good storm (which I missed) this has been the Worst Season Ever.
ReplyDeleteWere you around in 2015? I hike to almost 5000 feet up Bald Mountain north of Spada Lake in February- it looked like October- about an inch of snow.
DeleteThe interesting thing with this dry streak is that it kicked off with milder temperatures, but the temperatures have gotten cooler as it's progressed. Fortunately, there hasn't been a super inversion trapping the entire region under fog, and the daytime highs have been around seasonal averages.
ReplyDeleteThe opposite seems to have happened out at the coast. Temperatures feel warmer now than they were at the start of this dry streak. Part of that has to do with the wind chill. It was breezier when the streak began than it is now.
DeleteOne thing I noticed is lack of an inversion where nights in the lowlands haven’t had to deal with cloud cover. What conditions make it so we’re seeing the sun this time around?
ReplyDeleteAs Cliff pointed out, this is not uncommon in January. We always get a few days of sun in the middle of the month, but as he says, ever 4 years or so, we get a spate of 2 weeks of sunshine. This year has been in some ways, a year of the extremes, extreme sunshine mid January, but a massive atmospheric river in Dec causing all kinds of flooding. Both are not unheard of here, in fact, they do occur Semi regularly around these parts.
DeleteWeather news today said it hasn't been this dry in mid-January since 1963. Your data appears to contradict this although it appears that dry Januarys are rarer.
ReplyDeleteYou might not see it as climate change, but 2025-2026 appears likely to reinforce the long-term trend toward lower Washington snowpacks, which is driven by climate change. They don't make La Ninas like they used to ;).
ReplyDeleteJerry.... there is a slow decline of snowpack...at least in part driven by climate change. Not an emergency. Not a crisis. We have plenty of time to deal with the issue (eg. more reservoir capacity)..cliff
DeleteCliff - how about adding a column to your analysis to show the average high temperature and average low temperature during those time periods. My memory from living here over 60 years is that we frequently get a period of dry weather in January and it is very cold. How about looking at the wider picture?
ReplyDeleteThat is true, we have, but the temps overnight have been on the cold side, but the daytime temps have remained more or less, normal.
DeleteLived in this area for most of the past 61 years and was born and raised here, so recall some bitterly cold weather during weather like this too. Remember, we had been in a a mild La Nina year, which means not as cold, but definitely wet and may still be in a dying phase of La Nina if I'm not mistaken.
Haven't looked in awhile. Just want to know when snow will return to the North Cascades and if the snow will be followed by rain or stay cold blower?
ReplyDeleteOver the dry period we've had pea-soup fog or deep frosts. Damp pavements are now freezing over before sundown. When the precipitation restart could it be snow time in the low lands?
ReplyDeleteforget about dry - that is not at all what is meteorologically notable about the past week or so.
ReplyDeleteThe Freezing level has been consistently above 2000 meters for that entire period and most of it has been 3000 and even up to 4000 meters all.
do you mind digging up the stats on that?
Looks like it will be longer than 13 days. The next rain keeps getting pushed back.
ReplyDeleteIronically, I personally always feel colder on these clear winter days even when inside. The low dew points actually raise the minimum comfort temperature, at least for me. More skin evapotranspiration equals more cooling.
ReplyDeleteIn the Ellensburg area there has been much fog, little wind, and temperatures only varying a little about the freezing mark. A couple of "teens" this weekend might be the low for the month.
ReplyDeleteThe "Silver Frosts" {aka hoarfrost} have been picturesque.
The rain keeps getting pushed back. Some models only show a few sprinkles next week and push the rain North into BC. At first I was happy to see a week or two of dry weather but this is getting stupid with the models having so much trouble with the timing of breaking down the ridge. It's clearly not going to break down for awhile. At this point it would be best to go with persistence and expect very little rain for the next 2 weeks at least
ReplyDeleteThe current operational run of the Euro shows a series of fronts coming in, starting around the 26th. Some of them look quite wet, and it looks like everything is coming from the southwest — so the snow level is going to stay well above the lowlands.
DeleteOf course, the Euro ensemble might say differently. These operational model runs have been bouncing around more than usual lately, or so it seems.
This week, there has been an inversion in Puget Sound of sorts, fog, but not all the way to the ground, but the Kent Valley gets it quite thick, not so much this morning, thankfully as I commute from Tacoma to Kent via Kent Des Moines Rd and I-5. In fact, I think it snowed a little in parts of Kent as my place of work, it looked like it got a sprinkle and thus a little dusting on one side of our building, clear on the other side (north side got the snow, south, not so much) and frosty too.
ReplyDeleteHave had to do some scraping of frost on mostly the windshield (front, mainly) some mornings, leaving around 6AM.
One thing I HAVE noticed, being clear and sunny, it remained daylight until nearly 5pm, arriving home around that time and it was noticeably lighter than it had been at around the same time.
To someone who is weather savvy: why does my iPhone say there will be a low of say, 39f. Yet each morning I’m scraping frost? I don’t have a thermometer for outside (will get one) but I see large discrepancies in what is reported (typically above freezing) and what I observe (frost on windshield). I don’t live in an area that should have a cooler microclimate.
ReplyDeleteWith clear skies, frost can form even with above freezing air temperatures on account of radiative cooling. That is, because the cloudless night sky provides is not much of a heat source, objects emit infrared radiation into space and do not receive much of any radiation back. If this radiative flux is greater then the conduction of heat from the ground and atmosphere, frost will form.
DeleteThank you!
ReplyDelete