New England Weather This Week: High Pressure

After some active weather last week, New England will revert right back to quiet and bone-dry weather for this week. Temperatures will also be swinging back and forth.

Below: 7-day precipitation outlook:

MONDAY & TUESDAY

There's little change in the overall setup today compared to Sunday, so it will be another sunny and very warm day. With high pressure to the west, humidity will drop a notch from Sunday. Temperatures aloft are also slightly cooler, so the day will be a bit cooler as well. A backdoor cold front will drop through New England tonight into Tuesday, beginning a change in air mass.

This change will be gradual, so another warm day is expected on Tuesday. With the backdoor nature of the front, coastal areas and northern Maine will be the first to cool Tuesday afternoon, with temperatures likely dropping into the 60s through the afternoon after another day of widespread 70s.

Below: Temperature departure from average Tuesday evening:

WEDNESDAY-FRIDAY

A large area of Canadian high pressure will build into the region behind Tuesday's cold front. This will bring a much cooler air mass to the region for Wednesday and Thursday. Widespread highs in the 50s north and 60s south are likely both days. A rather strong pressure gradient between the high pressure centered just north of New England and the passing Hurricane Humberto well offshore will allow for breezy conditions. Northeast gusts of 20-30mph will be possible, adding to the October chill in the air.

With strong high pressure sinking southward, Wednesday night and Thursday will feature strong radiational cooling conditions. Clear skies, no humidity to speak of, and weakening winds should allow temperatures to bottom out both nights. Widespread low in the 30s are possible across the region with 20s across the northern tier and higher elevations. Southern New England will likely pick up their first frost advisories of the season this week.

Below: GFS showing potential temperatures in the pre-dawn hours Thursday. Note that these models tend to run a bit too warm when strong radiational cooling conditions are expected, so you can likely take a few degrees off of these for actual lows:

The high pressure system will likely move directly over New England Thursday night before sinking south of New England on Friday. After another chilly start Friday morning, temperatures will begin to warm up for the afternoon. Friday will act as a transition day from the cooler air mass right back to a warmer one for the weekend. Widespread highs in the 60s north and 70s south will return.

Tropical Storm Imelda will be diverted away from New England by this sprawling high pressure system. This will set up a blocking pattern reminiscent of a Rex Block (named after the meteorologist who discovered it). This block involves an area of high pressure located directly north of an area of low pressure. This will slow down Imelda's movement through mid-week before the storm is shoved around the high pressure system, well away from New England.

Below: Hurricane Imelda's cone. The cone is pretty clearly bending around the northeast's large high pressure system:

WEEKEND

This big, bold high pressure system will remain centered to New England's southwest through the weekend. This will set up a southwest flow and warm air advection once again. Widespread highs well into the 70s will likely return. There are decently strong signals already for temperatures to reach 80° across lower elevations of southern and central New England. Outside of these warm temperatures, the sprawling high will lead to bright, sunny skies and continued bone-dry weather.