Dry today with increasing clouds in southern areas; light to moderate rain in southern areas tonight into Monday night; then dry and cooler through Friday with frost and freeze outside urban areas and large bodies of water; warmer and breezy next weekend with at least light rain likely; then cooler and eventually cloudier following week

Plain-language summary:

 

It will be dry again today, though with increasing clouds ahead of an approaching storm in southern areas. Light to moderate rain will fall from Vermont to southern Maine tonight through Monday night, with areas to the north staying dry and only seeing increased clouds. It will turn cooler and breezy Wednesday before winds lighten later in the week with widespread frost and freeze outside urban areas and away from large bodies of water then, all while remaining dry and mostly sunny. It turns warmer and breezy next weekend with at least some rain likely for our region. It then likely turns dry and mostly for a couple of days and then cooler and cloudier for the following week, though it remains to be seen if any major rainfall can occur. Regardless of rainfall, the more up-and-down temperature pattern and increased cloudiness will be more typical of late autumn, even if the lack of true arctic air will mute the cooldowns somewhat.

 

Meteorological discussion:

 

Dry and mostly sunny today, especially in northern areas, then light to moderate rain in southern areas tonight through Monday night 

 

Today will be another familiar dry, sunny day except from southern Vermont to southern Maine as a big surface high-pressure and upper-level ridging dominates the region, especially in Quebec. It will also be warmer than earlier in the week in the sunnier areas in northern New England and especially southeastern Canada, though not nearly as warm as last weekend. However, an early-season Nor'easter slowly coming up the East Coast will spread thickening clouds to southern areas this afternoon and then eventually a period of light to moderate rain south of the U.S./Canada border and south of central Maine tonight into Monday night. The actual low-pressure center will be just off the South Carolina coast, but it is also interacting with a weak disturbance extending well to the northeast over the western Atlantic and another one over upstate New York, leading to the rain shield expanding well to the north into central New England. However, the blocking ridge to the north will block the movement of the overall storminess any farther north, and the storm will then stall out, occlude, and weaken, with the rain shield to the north collapsing by Monday night. As such, areas north of the U.S./Canada border will only see increasing clouds with no rain to relieve the drought. Even southern areas will receive much less rain than areas in the coastal Mid-Atlantic U.S., though up to 1" (25 mm) is still possible in some areas from southern Vermont to extreme southern Maine. The rain and clouds will also cause cooler daytime temperatures tomorrow south of the U.S./Canada border and south of central Maine.

 

Source: TropicalTidbits

 

 

Dry afterward through Friday, turning cooler again mid-week with widespread frost and freeze likely late week 

 

With the storm's miss for northern areas, those areas will have to wait a while before any seeing any drought relief, with little or no rain expected until at least next weekend. Despite this, the lack of unseasonably warm temperatures and lowering sun angle will lead to lower evaporation and likely prevent the drought from intensifying much further. A dry cold front will arrive Tuesday night, with another big Canadian surface high-pressure system approaching for Wednesday and Thursday, though the leftovers of the previous storm will still be moving very slowly off the East Coast and reintensifying south of Atlantic Canada, which will keep the chilly northerly flow into our region for several days, and with the surface high-pressure system remaining to the west, there could initially be enough low-level moisture to still promote low clouds on Wednesday, especially along and northwest of the Appalachians, something that becomes more and more common as autumn progresses. The NAO turning negative is aiding in slowing down weather systems and amplifying the upper-level wave train. Eventually, the surface high-pressure system will slowly move east into our region by Friday, with lighter winds and greater chance for another widespread frost and freeze outside urban areas and away from large bodies of water.

 

Source: TropicalTidbits

 

 

Source: Climate Prediction Center

 

 

Turning warmer and breezier next weekend with likely some rain 

 

By Friday, a deep upper-level trough will move into the western U.S., leading to a surface low-pressure system ejecting from the Rockies and a downstream upper-level ridge and warmup with southwesterly flow in eastern North America, including our region. It might be mostly sunny initially, but then clouds will increase as the storm slowly approaches our region, likely arriving next Sunday or the following Monday. The amplified upper-level weather pattern likely favors a low-pressure track northeastward into the Great Lakes and then north of our region, meaning that the heaviest rain stays off to the northwest, with our region turning breezy and warmer with at least some rain likely with the warm front and then cold front.

 

Source: TropicalTidbits

 

 

Perhaps drier and sunnier for a couple of days after next weekend before turning cooler and cloudier for following week, though not clear if any major rainfall

 

After next weekend's storm, another Canadian surface high-pressure system is likely to lead to a couple of dry, mostly sunny days again, though not particularly chilly as the high-pressure system is not tapping into any arctic air. However, that is likely not to last long as later that week, the whole wave train slowly moves eastward with a likely shift to an upper-level ridge/trough in western/eastern U.S. respectively (+PNA), with the -NAO leading to a slower-moving and less progressive weather pattern allowing for the mid-latitude jet stream to dip south with cold air from the west and northwest coming into our region. Right now, it is not clear if the cold air will come straight from the north like this week's cold shot, or if it will come south into the Great Lakes first and then push eastward, in which case the cold air will be modified. It is also not clear if we will see substantial storm systems providing a prolonged period of light to moderate rain that would be needed to truly relieve the drought, though the upper-level troughs and cyclonic flow predicted tend to lead to low-level moisture and clouds and even showers, especially at this time of year when Hudson Bay, the Great Lakes, and all the other lakes in eastern Canada are not frozen yet and supplying the boundary layer with moisture. This would lead to cloudier weather more typical for late autumn and lower evaporation rates. The temperature swings are also more typical of late autumn as the mid-latitude jet stream pushes south into our region and strengthens with the strengthening north-to-south temperature gradient. However, the northwesterly flow associated with the upper-level troughs is still largely detached from the true arctic air (perhaps at least partially due to the AO remaining neutral or slightly positive), and the arctic it self will be much warmer than average. This will mute the temperature swings somewhat and cause the average of the temperature swings to still likely be above the climatological average even with the +PNA and eastern North America troughs.

 

Source: TropicalTidbits