After an unusually warm Thanksgiving Weekend, today (Cyber Monday) and Tuesday will still be rather warm for late-November. In most cases, even despite some morning fog and clouds, afternoon temperatures will be running in the mid and upper 60s. Some temperature records could be approached, but most do seem “a little out of reach” for today. The current surface map is showing a strong ridge of high pressure located in the western Atlantic. Meanwhile, there’s a wave of low pressure and a cold front in the process of pushing across eastern Canada. Also, there’s going to be a “blocking pattern” setting up in the Eastern U.S. during the next day or two. This is because an upper-level low pressure system, or a pool of cold air and strong jet stream energy now located in the Tennessee Valley, is going to “seal itself off” from the polar branch of the jet stream — and, it is expected to meander across the Southeast today and tonight before it pushes through the mid-Atlantic states and into the Northeast later tomorrow, tomorrow night and Wednesday.
It’s also important to remember that while temperatures in most places this afternoon will be similar to tomorrow’s, today will be a “dry day from start to finish.” Conversely, tomorrow will bring a period of rain to many places, albeit rather light at the very start.
As the low pressure system tracks to the north and east, the rain will essentially follow it: first taking place south of the Mason-Dixon Line, and then spreading up the I-95 corridor during the afternoon and during the evening. The “steadiest rain” associated with this low pressure system will occur around here later tomorrow afternoon and early tomorrow night before it begins to lift out to the north and east. The consensus amongst the global models indicates that we’re probably going to see between 0.50″ and 1.00″ of rainfall tomorrow and tomorrow night. In the wake of the passage of that low pressure system (and a cold front) on the surface weather chart, Wednesday may still provide us with a potentially tricky situation. Even though there’ll be some drier air sweeping into many coastal areas from the south and west, the pool of cold air aloft that will tend to linger behind these surface features will generate instability, and could trigger a couple more showers.