Thursday, The Fourth of July 7 a.m.
These are dog days of summer. They were originally named for when the dog star Sirius rose about the same time as the sun. The astronomical connection no longer exists, and Sirius is a radio network, but the dog days have come to refer to the 40 or 50 days when it is likely to be hottest.
As we sniff out this afternoon's tail, a stray thunderstorm can occur almost anywhere ion the Northeast, but most of the packs of showers will be west and north of I81. However, thunderstorms can be terrierizing. Sometimes you think a storm has more bark than bite, and then all of a sudden a cloudburst of rain is unleashed and it rains cats and dogs. When this happens, don't step in a poodle.
The thunderstorms do cool it off a bit, but the air won't feel like it came by Labrador Retriever. Instead, humid air will hound us, and afternoon temperatures should reach well into the 80s to near 90 before the day fleas. While we are sounding the beagles for the possibility of thunderstorms, we should tick off many hours this weekend when sunshine gets a new leash on life.
Early next week It's the samoyed story of hot and humid, but if you think all of next week will be dry, you're probably barking up the wrong tree. When a thunderstorm does attack, however, pay heed to those pointers about moving to a safe place. Make no bones about it: thunderstorms can be ruff.
Sam the dog likes to stay indoors when it is hot, but he posed for this picture to celebrate the dog days.
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.