Wednesday 9 a.m.
Today is national turtle day, and by coincidence the Northeast is experiencing a slow-moving weather pattern. With a front separating cool air from hot air likely to be in the Northeast this weekend, offering a confident forecast for each day of the Memorial Day weekend would really be sticking my neck out. If I am right, you'll say I told the truth... but if I am wrong you could claim I amphibious.
One thing I want to stress (and at this time of year, this is really not thinking out of the box) the presence of a frontal zone and quickening flow aloft can lead to an outbreak of severe thunderstorms. For the Northeast, we should be alert for that possibility this weekend.
Thunderstorms will be hit or miss this afternoon from New York state to Virginia. So, picking up on the turtle theme, keep in mind that if you are out with friends this afternoon you might look up and say "there's a thunderstorm coming tortoise."
OK. We crawled to this slowly, but here's the video:
In Boston and New York City, the cold may feel most harsh late tomorrow and tomorrow evening. The temperatures will not have hit bottom by then, but gusty winds will sharpen the chill.
One concern: the chance of cold frontal snow squalls that could move all the way to the East Coast tomorrow night. Sudden snow squalls have been implicated in chain reaction collisions that turn deadly and damaging.
These two maps show the change from the very, very cold flow likely this Saturday to the much milder Pacific-origin westerly flow later next week.
When we look more closely, we see a variety of disturbances embedded in the main current, each capable of temporarily increasing or cutting off the chance of snow. This map shows the setup:
This map shows the circulation around the offshore storm and a larger but less intense storm moving into the Great Lakes. With this sprawling storm likely to be in the region for several days, the weather can vary widely.
...speculation about a snowstorm Monday or Tuesday, and one is still possible. However, timing and placement remain elusive. This map shows the GFS ensemble mean "solution" for Tuesday morning showing snow just off the New England coast. Watch this story evolve on accuweather.com all weekend.