I’ve noticed this for a few days and now it’s becoming a bit more obvious. Models are having issues with what to do with our upper-level ridge. For quite awhile it’s been looking like our ridge will be replaced by an upper-level trough later this upcoming week. Now, over the past 5 days or so, models are keeping the ridge a bit closer to us and putting it off in time. Here is the map of 500mb heights and anomaly for 15 days into the future. I showed this on Monday. It’s valid Tuesday the 3rd on the ECMWF:
Now (as of last night’s 00z run) the ECMWF looks like this:
See the difference now that it’s an 11 day forecast? Ridging is closer, although it supposedly will eventually pop back up a bit farther to the west eventually. This is an interesting development I’ve been watching for a week. Hmmm, not sure if it’s just a delay to the pattern change or if it means there won’t be all that much change in general for early March. Check out the pathetic snow total from last night’s ECMWF out to 10 days…less than a foot around Mt. Hood! That’s because weak systems coming around the top of the ridge don’t have much moisture when they come in from the north or north-northwest. This will be a drier than normal pattern.
Enjoy the sunshine, I see it’s coming out and I’m headed outside for the weekend!
Chief Meteorologist Mark Nelsen