Unsettled Weather Pattern Continues for New England Before Cold Shot Next Week

As of this morning, the latest low pressure system to bring New England showers is sitting just north of the region. This has lifted a warm front through the region. This has placed much of New England in the warm sector, allowing for a mild start to the day for all but northern Maine (where the warm front hasn't reached as of mid-Saturday morning). As the system to the north exits, it will drag a cold front across the region, but the cool-down will be gradual through the day. The passage of the cold front will see little to no shower activity.

A surface ridge of high pressure will very briefly build into New England for the first half of tonight. This will allow strong cooling conditions for the first half of the night, but an approaching system will cause temperatures to stall and possibly rise in the hours after midnight. This will come as a system over the Ohio Valley lifts its warm front into southern New England Sunday morning. Thermal profiles may allow for snow or a wintry mix across Vermont and northern New Hampshire Sunday morning. This will come as these areas will be on the north side of the cold front Sunday morning.

This setup will allow for warm air advection to occur through the day. This will allow for rising temperatures after a cold morning for southern and central New England. The northern tier will likely remain north of the warm front and stay generally chillier through the entire day. As always with this setup, it's tough to say just how far north the warm front will push by Sunday afternoon, but it likely won't make it too deep into northern New England. Areas south of this front will likely push well into the 40s and low 50s while northern areas are apt to stay in the 30s and low 40s.

Below: FV3 showing potential temperatures around early afternoon Sunday:

Showers will likely increase from south to north as the afternoon and evening go on. This will continue into the first part of Sunday night. By midnight, a majority of the precipitation will likely have pushed into Maine (as well as lingering in western Vermont), with spotty showers elsewhere. Showers will tend to be on the lighter side throughout this event, with a widespread quarter to half inch likely through Sunday night.

Areas outside of the mountains should see all rain with this one, with some mixing for the mountains and northern valleys. With warmer air aloft and colder air at the surface across northernmost New England, a period of freezing rain will be possible. This would be most likely across the valleys of Vermont. Any mixed precipitation across most northern areas will likely change to plain rain by Sunday evening.

Below: HRRR showing hourly weather from around sunrise Sunday through midnight:

As the center of the low pressure system lifts north and west of New England Sunday night into Monday, a secondary area of low pressure may form around coastal New England. This will allow for another round of showers to develop for Monday, along with some gusty winds. Overall, this shouldn't bring too much by way of impacts as the secondary low pressure system looks to remain on the weaker side.

Most guidance keeps this low pressure system above 995 millibars, making it rather weak. Wintry precipitation across Vermont and northern New Hampshire could amount to a couple inches of snow and minimal ice. Winter weather advisories could be issued in these areas, which would be the first of the season for New England.

Below: RGEM showing potential weather Monday evening:

A strong cold front will push through New England (and across the entire east coast all the day to Florida) later Monday and Monday night. This will bring a shot of Arctic air through the east. This blast of air is more reminiscent of a mid-winter Arctic blast than an early-season cold front. Tuesday will likely see temperatures bottom out, with highs in the 30s north to mid 40s south. This will be cold for the time of year, but it will be the south that will see the brunt of this cold snap (relative to their seasonal averages).

A ridge-in-the-west-trough-in-the-east pattern will set up next week, with chilly temperatures and continued unsettled weather on tap for New England. While Tuesday will be the coldest day, much of next week will remain on the chilly side. Broad cyclonic flow will be over New England. This will create plenty of clouds and the potential for quick, pop-up showers and flurries Tuesday through Thursday. Precipitation will be most likely within the mountains. It's possible a subtle shortwave enters the area later Wednesday to Thursday, allowing precipitation to become a bit more widespread across New England, but we'll see.

Below: 500mb height anomaly next Wednesday, showing troughing remaining over New England: