I hate to be the bearer of bad news, but if you’re a warm-weather lover in the Eastern US, longing to slip right into the summer feeling as we head into May, you’re out of luck. Looks like we’ve used up our warm days during winter/early spring and are now paying the price for that with a steady stream of cold, rainy weather.
As we discussed last week, high latitude blocking (-NAO), continued western banding (+PNA), and still negative AO are working together to keep the Eastern US cooler and storm.
This pattern remains solid next week. Plus, it will bring another wave of unseasonably cold air to start the week.
Ugly isn’t it?
Meanwhile, extending across the western US will allow temperatures to rise significantly above average for many people. However, after the winter they’ve been through, they deserve to be warmed up.
If you look back at the 500 mb elevation anomaly map at the top of the blog, you’ll notice that as the week goes on, the pattern starts to change some.
- Ridging over the West (+PNA) started to break and was replaced by a drop.
- The high-latitude intercept west of Greenland persisted (-NAO), but then intensified as it moved further west.
This leaves us with a trench in the West, a strong trench concentrated in the North of Canada, and a trench in the East.
This pattern is called the Omega Block (due to the way it resembles the Greek letter Omega). It consists of an area of high pressure surrounded by an area of low pressure on both sides.
What does a model like this produce in terms of reasonable weather?
- Those who live under the mountains often have sunny skies and warmer than average temperatures.
- People below either of the two lows typically experience periods of colder, prolonged unsettled weather.
Unfortunately for those affected by lows, this type of blocking can be difficult and slow to deal with.
That seems to be the case with this particular forecast block. Using temperature anomalies, we can see the signal I mentioned grow and linger before easing some mid-May. Yes – mid-May. Two more weeks.
Both EPS and GEFS have similar solutions at the moment. But can the block delete faster? It can. It can also last a little longer. Right now, however, based on general guidance, mid-month seems like a good predictor of when we’ll see our next big change.
About the author
Meteorologist – ’22 Mississippi State Writer for Weather.us and Weathermodels.com. Focus on weather communication. BoyMom x1, CatMom x5. Twitter: @MegGulledgeWX