Sluggish, cold spring reinforced by tropical cyclone
Sunday, March 25, 2018, 11:31 - Here we are in the official weekend of spring, but winter, it appears, is refusing to step aside.
Many hope that the passing of the vernal equinox means we dive directly into mild temperatures and blossoming flowers. But spring, being a transitional season, can be a volatile period with little rest for the winter weary. As we say goodbye to March and transition into April, our atmosphere looks to take this hot-blooded nature to heart.
What do the next three months have in store for you? | Find out in our exclusive 2018 Spring Forecast
FINAL DAYS OF MARCH
We're looking at a 'Tale of Two Airmasses' this week, as Arctic air spills into the Plains. Temperatures, at times, will be several degrees below seasonal by the end of the week and a potentially potent snow storm looks to finish it off for some across the northern tier. Parts of the Pacific Northwest, on the other hand, will be flirting with the low 60s for the final days of March.
The image below shows the temperature anomaly forecast for Friday March 30, with the core of the cold placed over the Canadian Prairies. The deep purple (think Barney color) depicts temperatures 20 to 30 degrees below seasonal for the end of March.
Temperature anomalies from the GFS model for Friday March 30. Image courtesy WeatherBell.
Meanwhile, in the East, we're looking at highs into the 70s for Atlanta and Raleigh-Durham, and the mid-to-upper 50s as far north as New York City and Boston. But this will be short-lived and could potentially end as a shot of snow late next week (stay tuned).
FIRST WEEK OF APRIL
The cold over the west will continue to leak into the rest of the country as we enter the first week of April. Below-seasonal temperatures will be fairly widespread from the Northwest to the southern Plains to the Great Lakes, while the Southwest and Southeast surge warmer. While the northern tier of the country may be dealing with the leftovers of winter weather, we could be looking at an early start to wildfire season across the South.
Temperatures anomalies from the GFS model for Tuesday April 3. Image courtesy WeatherBell.
It may seem a bit far-fetched, but tropical cyclones on the other side of the world can be a big driver for our weather across North America. It's a known process called 'teleconnections,' and the idea is that a powerful tropical system in the western Pacific Ocean holds a substantial amount of heat and energy and if the storm migrates into more northern latitudes ('recurves'), that heat is injected into our upper atmosphere and influences weather patterns across the northern hemisphere. As a result, our jet stream becomes overly amplified as large troughs (cold air) and ridges (warm air) take shape – and a common outcome leaves a digging trough over central and eastern North America: Colder than normal.
So why am I reviewing this phenomenon? Well through the final days of March, a typhoon will trace out this effect and aid to reinforce the cold over North America throughout the first week of April as it recurves in the western Pacific Ocean.
WILL IT BE FRIGID?
Yes and no. By April standards, temperatures will be rather chilly. But they aren't temperatures we haven't experienced before this winter. It’s important to note that our seasonal averages throughout the month of April quickly spike, so what you’ll likely experience is just a continuation of cold weather versus a shocking drop. We’re simply going to continue with the late winter trend a little longer rather than springing quickly forward, which for a transitional season isn't abnormal.
Welcome to spring!