BLOG: Warm Start
While temperatures did exceed our expectations Monday, the sky cover and lack of any rain were aspects of the forecast that were still pretty much "on target." Tuesday, temperatures will probably still climb into the 60s, even despite plenty of clouds, as well as some fog and a bit of drizzle.
The current weather map is showing the high pressure system, which promoted our recent unseasonably warm weather, is now finally beginning to drift a little farther to the east and into the North Atlantic. On the "flip side," there's a very strong upper-level low pressure system that continues to spin its wheels across the Tennessee Valley. Overnight, there has been snow in western parts of Tennessee and Kentucky, and there'll be a swath of precipitation Tuesday afternoon across Indiana and Lower Michigan heavy enough (combined with air that will be cold enough) to yield a few inches of snow.
These types of upper-level low pressure systems have their own "pool of cold air" aloft to work with, and wherever the steadiest and heaviest precipitation occurs beneath its center of circulation will almost always result in a heavy, wet snow during late-November.
Along the Eastern Seaboard however, a much milder and moist flow of air associated with a wind flow primarily out of the south (shifting from the southeast in the morning to the southwest later Tuesday) will result in some rain. The bulk of the rain will be occurring in the afternoon and early evening, as it pivots northeastward along the I-95 corridor. The regional radar mosaic is showing a corridor of rain, associated with a front, that is drifting northeastward through Virginia and the Carolinas. North of that well-defined area of rain, there are some echoes which are popping up across eastern Pennsylvania, Maryland and just off the coast of Delaware. Therefore, we should be allowing for a shower and some drizzle at almost any time in the morning, but should also be anticipating the steadier rain will spread from southwest to northeast later in the afternoon and the evening. This should be followed by drier air, as well as partial clearing before dawn. Rainfall totals will average 0.50" - 1.00", and most of it will occur during a 6-hour window between noon and 6 or 7 p.m. across the greater Baltimore area. For the most part, temperatures will wind up in the lower 50s by daybreak Wednesday, which is still several degrees above normal for this time of year.
With winds out of the west and southwest Wednesday, that upper-level low is being forecasted to lift northeastward and into western New York state. This should promote a drier day for areas east of the Appalachians, with some sunshine returning; it'll also be a bit breezy. Most temperatures should be in the lower or middle 50s tomorrow afternoon. As a high pressure system establishes itself in the eastern region Wednesday night, Thursday and Friday, the weather during the rest of the week will be relatively tranquil... Have a good day!
