Plain-language summary:
After the wettest and cloudiest week in 3 or 4 months across the region, it will be dry and seasonably cool through Wednesday. Clouds still dominate today and Monday, especially along and northwest of the Appalachians, but at least partial clearing is likely for Tuesday and Wednesday in these areas, with coastal areas perhaps turning cloudier. Frosts and freezes are likely on clear nights away from urbanized areas and large bodies of water. A storm could bring heavy rain and strong winds Thursday and/or Friday. It then dries out for a few days but perhaps still remaining rather cloudy. It likely turns colder, though not extremely cold, and unsettled later the following week, with the first chance of snow for most. This weather pattern should continue to slowly ease the drought.
Meteorological discussion:
Dry and seasonably cool through Wednesday, still mostly cloudy for most today and Monday before gradual clearing in northern areas through Wednesday
After the wettest and cloudiest week in 3 or 4 months across the region, it is now dry and seasonably chilly as the slow-moving cut-off low has weakened and moved off to the east and is replaced by a broad slow-moving high-pressure system over eastern Canada. However, it is still rather cloudy in many places, especially along and northwest of the Appalachians as low-level moisture is trapped under the subsidence inversion, and the sun angle is too low to break up the low clouds much at this time of year. This is a frequent occurrence in late fall into early winter. Southeast of the Appalachians, the subtle downsloping resulting from the weak northerly flow is just enough to break up most of the clouds. The clouds will likely eventually break northwest of the Appalachians by Tuesday and Wednesday as the atmosphere slowly dries out, whereas coastal areas could actually get cloudier as a surface low-pressure system moves into just offshore the New England coast that switches the flow to easterly off the Atlantic Ocean and also brings both marine low-level clouds and mid-level clouds from the broader storm system. However, the blocking high-pressure system to the north over Quebec (connected to the high-latitude blocking or -NAO that persists) will squash the storm far enough to the south to prevent any rain for the region, and areas north of the U.S./Canada border will turn increasingly sunny. The location of the surface high-pressure system to the north of our region will prevent any warmup that was previously expected during this time, and widespread frosts and freezes are likely where there are clear skies at night, except for heavily urbanized areas and shorelines of large bodies of water.
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| Source: TropicalTidbits |
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| Source: Climate Prediction Center |
Storm arrives Thursday or Friday with potential heavy rain and strong winds
Unlike previous dry, sunny spells, this dry and somewhat sunny spell will already be over by later Thursday, as another storm approaches from the southwest. It is a rather amplified setup that should be amplified enough to push into and weaken the blocking ridge and bring a widespread rain to the region. It could also be accompanied by strong southeasterly or easterly winds, especially along the coast and in downslope regions just west of the Green Mountains and Adirondacks. Most likely, the storm tracks just to the northwest, with southeasterly winds leading to upslope enhancement along the Green and White Mountains and to the southeast, as well as in the Laurentians, with less rain in the downsloped Champlain Valley, though if it tracks a little more to the east, more like an early-season Nor'easter, there would be a more even distribution of rainfall. The timing of the storm is also still a bit uncertain due to the relatively slow-moving nature of the blocked pattern, with the storm coming anywhere between Thursday afternoon and later Friday. However, it is becoming more certain that Hurricane Melissa will be too far east to have a direct influence on our weather, though Melissa could impact parts of Atlantic Canada and there may not be much of a separation between Melissa and the extratropical storm impacting our region, with perhaps some moisture from Melissa being siphoned into the storm in our region.
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| Source: TropicalTidbits |
Turning drier by next Sunday but still cloudy for a few days, then colder and turning unsettled with first chance of snow for most
By next Sunday, the storm will have passed to the east, but lingering low clouds are likely as is common during late fall and early winter. The weather pattern becomes a bit uncertain; most likely, another a few days of mostly dry weather ensues, with a broad, weak low-pressure system passing to the south early the following week possibly bringing showers to southern areas but leaving areas to the north dry. The blocking pattern appears to weaken (NAO turning neutral), but the positive PNA will lead to a classic upper-level ridge in western North America and trough in eastern North America, which should lead to cool temperatures and unsettled weather at times. Given the northwesterly flow of chilly air associated with this type of weather pattern, it is likely that many locations will receive their first snowflakes, even measurable snowfall, with one of the low-pressure systems that reaches our region and taps into the greater supply of cold air, even at lower elevations, though higher elevations are still much more likely to receive accumulating snow, as is typical for this early in the season. Also, central and northern Canada is still much warmer than average and will likely remain so for the foreseeable future, limiting just how cold the cold air from the northwest can get, and temperatures aren't expected to reach anywhere near record lows, but warmth will also be largely absent though there are signs of a brief warmup later that week. The colder temperatures and increased storminess should continue to slowly ease the drought.
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| Source: TropicalTidbits |
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