Dry week except late Tuesday into Wednesday; week to start warmer, then turn cooler mid-week, and then turn warmer again for late week, perhaps finally starting a prolonged warm and mostly dry period

Plain-language summary:

Today is a cool day with morning clouds, especially on northern facing slopes, giving way to afternoon sunshine for most, with tonight being a cool night. A warmup will occur tomorrow and Tuesday with mostly sunny skies, though it will turn cloudier in northwestern areas on Tuesday. After some rain and a sharp cool down on Wednesday, it quickly dries out and turns warmer for late in the week and into the weekend. This could start a prolonged warmer and drier than average period, even as we go into September, with the average temperatures falling. With clear skies, nights could still be cool with valley fog, as often occurs at this time of year, if the wind is light.

 

Meteorological discussion:

 

A cool Canadian high pressure is moving into the region today, with lingering low clouds due to lingering moisture after yesterday’s rains trapped under a subsidence inversion, especially on the upslope northern facing slopes. The sun will slowly break up the clouds and lead to a sunnier afternoon for most. As winds calm down tonight, good radiational cooling will lead to a cool night. As the high pressure moves southeastward and the cool air mass moderates tomorrow and Tuesday, it will warm up, though clouds will increase in northwestern areas on Tuesday as the next system approaches.

 

Source: Penn State Meteorology

Source: TropicalTidbits

A low pressure area will track through northern Ontario and into central Quebec and then strengthen in the Canadian Maritimes on Wednesday. It appears that it will not be quite as strong and slow-moving as some models indicated earlier. It will bring rain and maybe some thunderstorms, but given the lack of deep tropical moisture and quick movement, widespread heavy rain is not expected. The storm and associated trough will steer Hurricane Franklin out to sea. Also, Idalia, which will likely be a hurricane at this point, will be too slow, and the trough will not be deep enough, for the trough to pull Idalia into our region.

 

Source: TropicalTidbits

 

Although Idalia will not directly affect our region, its presence to the south and potential stalling there could help build the ridge around it, leading to a quick warmup later in the week after an initial cold blast behind Wednesday’s storm. Though the exact position and timing of individual disturbances is uncertain this far out, as usual, this could mark the first prolonged period of broad ridging, dryness, and above average temperatures this summer. Though it will be September, and average temperatures are lowering, some summerlike temperatures are likely during this time, perhaps hotter than it ever reached in all of August. For now, it appears that the mostly westerly flow will bring relatively dry air in, precluding heavy rainfall. Still, given the longer nights, valley fog could be a frequent occurrence during nights with little or no wind, as often occurs at this time of year, given the relatively clear skies and ridging.

Source: TropicalTidbits