WEATHER BLOG: Clouds Moving In

A zone of high pressure holding steady near Nova Scotia Sunday and Monday will import slightly cooler air into the region through Monday. Moisture in the lowest few thousand feet of the atmosphere will bring areas of mainly morning low clouds Sunday morning and Monday morning (especially east of the city), with partial sunshine returning for both Sunday afternoon and Monday afternoon.

Meanwhile, a bubble of scorching mid-summer heat building across the central states Sunday and Monday will begin advancing toward the East Coast at midweek. A boundary separating the two different air masses will be the focus for clouds and spotty thundershowers. This boundary will slowly cross the Northeast states Monday and Tuesday, which will create an opportunity for spotty thundershowers though many places will remain dry. The best chance for rain on Monday-Tuesday will be north and west of the city.

Breezes from the southwest will replace the southeast flow at midweek as a new high pressure zone builds over the Southeast seaboard. At the same time, a large upper-level ridge of high pressure will strengthen across the Eastern third of the nation, setting the stage for some very hot days later this week. It will turn noticeably hotter on Wednesday, but the hottest day should be on Thursday when temperatures will rise well into the 90s, their highest values of the year. Higher humidity will accompany the heat, with real feel temperatures soaring to near 110. Sunshine will be plentiful, though some cumulus clouds will bubble up spotty thunderstorms in the late afternoons of Wednesday and Thursday ... mainly over the high ground well north and west of the city.