As one light snow event races off towards Newfoundland, another waits on our doorstep for tomorrow. Following light snow tomorrow, temps stay cool into Wednesday before warming up ahead of a more significant storm Thursday into Friday. This one should be mainly rain but quite a lot of it is expected. That storm departs Friday night leaving afternoon showers and thunderstorms around for the weekend as we sit under an upper low.
Overview: This Week’s Weather At A Glance
Here’s this week’s weather at a glance for those who just want the short version. I hate to say it, but there are no long term warm ups in the forecast and even the mid/late week warm spell will struggle to top out above 50F. April in Maine is cruel. Details on our two incoming storms are below.
The Setup: Tomorrow’s Snow
Low pressure is currently diving SE across the Great Lakes and will be making its way to SNE by tomorrow morning. It will be too far south for significant impacts here in ME but points south could see several inches. Snow will move in around daybreak and move out in the evening. It will be light and accumulations will be similarly unobtrusive. Because this system is much weaker than the one today, no crazy winds are expected.
Tomorrow’s Snow: Weak Upper Support Means Weak Storm
The reason this storm will remain weak and to the south is that above 15,000 or so feet, the storm doesn’t exist. In the image to the right you can see the upper level footprint of our storm today with very strong winds and a big dip. Tomorrow’s storm? It’s circled in red. If you can see any significant storm there, let me know because I’m having a hard time. The lack of significant upper level support means this one won’t have a chance to intensify or turn NE when it reaches the coast. The net result? Very little snow for ME and NH.
The Setup: Late Week Heavy Rain
Our next storm arrives late week with heavy rain likely. Notice the NW/SE orientation of the longwave features. This means that the trough to our west will be feeding tropical air northward into our area on strong S/SE winds. Those S/SE winds also mean that storms will be more likely to move up the coast when they develop as the individual shortwaves rounding the base of the trough. The end result? Heavy rain is likely at some point between Thursday and Friday. Exactly when and exactly how much rain falls has yet to be determined.
Late Week Heavy Rain: The Tropical Connection
When the rain does come, it will bring with it air straight from the tropics as the 12Z GFS PWAT map shows. This helps to establish fairly high confidence we will see heavy rain at some point late this week. The greatest threat for heavy rain will be Thursday night but it could fall any time Thursday or Friday. Guidance is indicating fairly significant rain could fall with amounts likely in the 1-3″ range. This could cause some rapid stream rises so be aware of that potential. Despite that, no widespread flooding issues are expected.
Next Weekend: The Return Of The Cold
Looking ahead to next weekend, the upper level low that brought the heavy rain Thursday/Friday will park over our area bringing cool and unsettled conditions. Expect temps to again drop back towards freezing with rain/snow showers possible. No accumulations or organized storm systems are on the horizon but showers driven by daytime heating will likely become a fact of life heading into the second week of April.
I’ll have more updates through the week.