Plain-language summary:
Warm, dry, and mostly sunny weather will once again dominate again through Tuesday, though with low clouds and fog in the valleys at night and in the early morning. Brief, light rain falls Wednesday along and northwest of the Appalachians before drying again for Thursday and Friday. A weak storm and cold front bringing rain on Saturday likely heralds a change to a more changeable, faster-moving, and cooler weather pattern afterward. More frequent cool, rainy, and windy days interspersed with some drier, milder days likely follow afterward.
Meteorological discussion:
Warm, dry, and mostly sunny weather will once again dominate as a slow-moving blocking ridge dominates over the Great Lakes region and southeastern Canada through Tuesday, suppressing the weakening remnants of Helene to the south of our region. There will be very little wind until southeasterly winds increase somewhat on Tuesday. With the increased ground moisture from the rain earlier this week, light wind, clear sky, and the lengthening nights of autumn leading to good radiational cooling and temperatures falling through the dew point, fog and low clouds will form every night in narrower river valleys, and maybe even in the broader valleys to a lesser extent. The fog and low clouds will burn off in the morning, though it may take until late morning in the deeper, colder valleys to fully dissipate.
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| Source: TropicalTidbits |
By next Tuesday, the blocking ridge will have broken down, with a more quickly-moving low-pressure system in northern Quebec bringing a weakening cold front on Wednesday. Southeasterly winds and clouds will increase initially, and then there will be a light, short-lived rainfall. However, the trough is quickly lifting back to the north as another trough entering western Canada (brief negative PNA) will pump the ridge farther east. As such, most of the rain and cooler air will dissipate once they get east of the Appalachians. Surface high pressure will quickly move into our region and then just off the U.S. East Coast by Friday, leading to warming temperatures again, though another shortwave trough will bring some rain on Saturday and a shot of cooler temperatures next Sunday.
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| Source: TropicalTidbits |
Another tropical storm or hurricane will likely form in the western Caribbean some time next week and move northward into the Gulf of Mexico, which could have implications on the weather in our region later on depending on the synoptic-scale mid-latitude troughs and ridges in the contiguous U.S. A trough will likely arrive into western North America next weekend and move into the central and eastern U.S. by the following Monday or Tuesday. If it is timed just right and is strong enough, it could pick up the Gulf of Mexico tropical storm or hurricane and slingshot and accelerate it northward into eastern New England, even favorably interacting with it such that it maintains its intensity, bringing heavy rain and strong winds to our region, like with Francine and Helene. The weather pattern does appear to be more progressive and faster-moving by then, without blocking ridges to block systems from moving northeastward. But this also means that the trough could just be not strong enough and easily push whatever tropical storm or hurricane out to sea, which is perhaps more likely at this point. There is also still the less likely scenario that the trough isn't strong enough or timed right to pick up the Gulf of Mexico tropical storm or hurricane, instead leaving it behind to stall or move slowly in the Gulf of Mexico for another several days.
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