The dry and sunny weather pattern continues, with much hotter temperatures. Sunday, Thursday, and Friday will be the hottest days so far this year, with some cooling on Monday and Tuesday especially for northeastern and coastal areas. The hot weather will peak on Thursday or Friday ahead of a cold front that will bring scattered showers and thunderstorms, mainly over the higher terrain, but dry air will prevent widespread thunderstorms or heavy rain. It will turn cooler afterward, but it still appears mostly dry for now, though there are uncertain signs that it could turn cloudier with more showers and thunderstorms with near to slightly below average temperatures in early June.
We are still in the middle of a very dry and sunny and now hotter pattern, with a broad, slow-moving ridge established over eastern Canada overtop a closed low over the southeast U.S. This pattern is leading to a very pronounced reversed temperature gradient, with sunny northern Ontario yesterday afternoon being 27F (15C) warmer than in rainy South Carolina!
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| Source: TropicalTidbits |
Locally, today will be the hottest day of the year so far for many inland locations north of the U.S./Canada border, with lower elevations reaching up to 90F (32C). As is typical of sunny days at this time of year, it will get hotter than most model guidance. The hottest temperatures will be east of the Appalachians, over eastern New Hampshire and eastern Maine, even close to the coast due to the offshore and downsloping westerly winds. However, with the deep westerly flow still cut off from any Gulf of Mexico and Atlantic moisture, the relative humidity will be quite low, possibly <25% in the afternoon like yesterday, which will prevent any storms from forming. The dry air through the column will lead to the continuation of the characteristic cloudless skies and large diurnal temperature swings of the past few weeks, not just for tomorrow but through at least Wednesday! With the recent rains in Alberta putting out the fires there, there will also be much less smoke aloft throughout the region to create hazy skies than many days recently.
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| Source: TropicalTidbits |
A subtle backdoor cold front will turn winds to light north and northeasterly for Monday, leading to somewhat cooler temperatures from Vermont northeastward, with the cooldown being the most pronounced in Maine and almost imperceptible in the southern Adirondacks. However, as the winds weaken and turn westerly again on Tuesday and Wednesday, it will heat right back up until reaching a peak on Thursday or Friday, where it could reach 90-95F (32-35C) in many lower elevation locations. Coastal locations will be cooler due to the lingering cooler air mass from the backdoor cold front, sea breeze, and lack of a strong offshore and downsloping background wind.
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| Source: TropicalTidbits |
The broad eastern Canadian ridge will slowly retrograde westward through next weekend, leading to more northerly flow aloft bringing a cold front around Friday. The air mass will still be relatively dry with no connection to the Gulf of Mexico or western Atlantic, but the heat and cold front could be enough to trigger scattered showers and thunderstorms, especially over higher terrain. However, while the dry air could lead to enhanced gusty winds with any storms that do develop, the lack of moisture will preclude widespread thunderstorm development and heavy rainfall.
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| Source: TropicalTidbits |
After the cold front, it will turn noticeably cooler, likely by next weekend, though the timing could change by a day or two. The deep northerly or northwesterly flow still appears unfavorable for cloudy and rainy weather, but if the ridge over central Canada amplifies enough, an upper-level low could cut off over eastern Canada, leading to cool, cloudy, and showery weather, though this appears less likely for now. Eventually, the ridge in central Canada could retrograde to western Canada, leading to troughing over the Great Lakes and more west-southwesterly flow over our area. The low heights and some moisture from the Gulf of Mexico would lead to more clouds, showers, and perhaps thunderstorms, something we have not really seen so far this year, with near to slightly below average temperatures for early June. However, I would not be surprised if the ridge stays far enough east or the pattern mflattens enough to prevent the deep southerly flow needed to transport abundant moisture into our area, and given the dry ground, not much moisture will be generated locally from evapotranspiration.
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| Source: TropicalTidbits |