Warming Trend Underway for New England Before Cold Front Next Week

Hurricane Erin is set to make its closest pass to New England today, bringing large waves and minor coastal flooding. Minor storm surge was observed during yesterday evening's high tide, and similar conditions will be possible during the Friday morning & evening tides. High surf will likely linger into Saturday. A Wind Advisory is also in effect for Cape Cod and the Islands through Friday afternoon.

The storm will pass about 450-500 miles away from New England's coastline. It will come just close enough to create some windy conditions across southeast Massachusetts. This increased wind will come due to the tight pressure gradient between Erin's low pressure and the high pressure to New England's north, which is helping to deflect the storm back out to sea.

Below: Wind conditions as of Friday morning:

Throughout this week, this high pressure to the north, along with Erin's persistent onshore wind, has led to cool and sometimes chilly (overnight lows) conditions for mid-August. On Wednesday, Worcester actually set a new record for all-time coolest high temperature for August 20th when it peaked at just 59°. Both of these features will now be leaving New England as the high pressure breaks down and Erin, rather rapidly, moves away today.

A new area of high pressure will slide into New England for this weekend. This one will be centered more to New England's south, which will promote a more southerly flow, bringing summer temperatures back to the region. High temperatures in the 80s will dominate from now through the weekend. Southerly flow ahead of a cold front that will cross New England early next week will also assist in bringing milder temperatures back. Saturday will likely see the warmest of the temperatures.

Below: Euro showing potential temperatures Saturday afternoon:

On Sunday, an area of low pressure will be moving to the northwest of New England. This will be dragging a cold front across the eastern United States over the next few days. Initially, it was looking like this front would cross New England on Sunday, but this front is slow-moving and it may even stall for a time just west of New England.

On Sunday, the front will likely remain to the west, with New England's northern tier most likely to see the development of showers and thunderstorms throughout the day. Across Vermont, there may be two rounds of precipitation, with the first coming in the morning and the second being convection driven in the afternoon. There will be ample shear for stronger storms, but very limited instability. The atmosphere won't be overly moisture-rich either.

This cold front will likely gradually cross New England through Monday and likely clear the region by Tuesday morning. This will spread the showers and storms across all of New England for Monday. As of now, this will promote a line of precipitation across New England through the day, with the best chance for scattered storms in the areas where the front crosses in the afternoon.

A weak secondary low may form along or just ahead of the front. Should this occur, a period of more widespread and steady rain could develop rather than just scattered afternoon activity. That will be the main area to watch as we move through the next few days. The trough may linger into Tuesday, promoting more scattered shower activity, mainly across northern New England. In all, northern and western New England will see the most rain, with total amounts likely dropping moving south and east as the front takes longer to arrive.

Below: Current 5-day precipitation forecast:

At this point, it looks like surface high pressure will once again take control after this frontal passage, leading to another week on the quieter side. Temperatures will likely cool off once again behind the front as the trough may linger aloft. At present, next week doesn't look quite as cool as this week, but trends will be watched.