This week I have been in New Orleans, attending the Annual Meeting of the American Meteorological Society. I spent a lot of time in the sessions dealing with the meteorology of western wildfires--will share some of the interesting findings in future blogs. I even gave a talk on western Washington/Oregon wildfires.
We are now experiencing and will continue to experience an unusually dry period on the West Coast, and that will be associated with cold and snow over the eastern U.S. Snowflakes may fall on the Big Easy.
The reason? A strong and persistent ridge of thigh pressure along the West Coast. For example, below is the forecast upper-level (500 hPa pressure, about 18,000 ft) heights for Tuesday morning. Wow.
A high amplitude ridge (orange/red colors) from coastal CA into the Yukon, with a very intense trough of low pressure extends to the Gulf coast (blue and purple colors).
Boy I am I glad I got out of New Orleans. Got to feel sorry for the gaters, though.
This atmospheric pattern sets of strong northerly wind from the Arctic to the substropics. A frigid atmospheric superhighway
Look at forecast temperature anomaly from normal for 1 PM PST Tueaday. Unbelievable.
Some areas of the southeast will be 30F or more below normal.
Take a look at the predicted snowfall totals through next week. Shockingly, New Orleans, southern Texas and northern Florida may see some flakes!
Now what about our region? With winter ridges like this, large contrasts develop between lower elevations and aloft. It will be COLDER than normal at low elevations and WARMER than normal at higher elevations.
Why?
Because the light winds and relatively clear skies associated with a ridge/high aloft allow cold air to settle in, usually accompanied by low level stratus and fog. Yuck.
To illustrate the low clouds, consider the visible satellite image early this afternoon around Washington State. Lots of low clouds around Puget Sound and in the Columbia Basin. There will be MUCH more low clouds next week.
But warmth will be close at hand. Just take a hike or drive into the mountains, where it could be as much as 20F warmer. A strong inversion will be in place.
High pressure is actually associated with sinking warm air aloft. In the summer, the media LOVE to talk about the "heat domes" produced by high pressure areas. Heat domes are also there in winter--they are just aloft.
So ascend approximately 1500-1200 ft if you want sun and warmer conditions.
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Cliff! We are heading down Jan 28th to NOLA. Love to hear if you have a recommendation of place to visit, food ect. Also, I know it's a bit out there, but will this pattern persist in NOLA? I will be the only guy in light jacket while everyone else in parkas if so. Love the cold.
ReplyDeleteDid you see this CBS Sunday morning report? Wonder if you reached out with your data on fires and climate change if they would listen and air it, or they would continue to try to scare people with this hype.
ReplyDeletehttps://youtu.be/ayGWZ3pM_MA?si=oaAy86xfojuhfnNx
Is this rex block ridge just a fixture in western and PNW winters now? Can't think of a snow season in the last 10 years where there hasn't been a "dry month" in the winter.
ReplyDeleteI agree with Kulharin. When does the rain return? We were ~6 inches off the rainfall norm last year and so far it looks dry this month too.
ReplyDeleteMy next blog....
DeleteCliff, the snowfall at Snoqualmie Pass during January appears headed for one of the lowest totals in awhile, and by an order of magnitude. As this is primetime for NW skiers, it would be fun to see some chart specifics / narrative around this huge miss. And given that it was projected to be a la Nina, it's even more of a bust.
ReplyDelete