High pressure to block hurricane remnants from New England again

As Hurricane Helene lifts into the interior southeast today, Yesterday's upper low that brought rain to New England will be sliding eastward, away from the region. The system's cold front will stall to the south of New England today, which may make cloud cover stubborn across the southern tier of New England. Regardless, skies will be on a clearing trend as the day goes on. With the upper low still near Nova Scotia, a few wrap around showers will be possible across eastern Maine.

Photo byNew England Storm Center

Friday will also see a ridge of high pressure begin to build into New England. This ridge of high pressure will once again protect New England from wet weather from the remnants of a hurricane. This is similar to a few weeks ago when Hurricane Francine was blocked into the south by high pressure over New England (though that ridge was stronger than this one). The same will generally happen again this weekend as Helene is forced to turn to the west over Georgia and Tennessee on Saturday.

While most of New England will be completely dry this weekend,there is a chance of some of the outermost fringe showers of Helene to push into western Connecticut on Saturday. The more scattered shower activity will remain in the Mid-Atlantic, but a couple quick showers may be able to wander into southwest New England just due to proximity. Saturday will feature plenty of clouds around (though not overcast all day), but overall dry weather for everyone else.

HRRR showing potential weather Saturday afternoon:

Photo byHRRR/Tropical Tidbits

After a generally mild Friday (widespread highs in the 70s, with some heading toward 80°) eastern New England will cool off again for the weekend as the high pressure brings back a cooler onshore flow. Areas farther west, well away from the coastal influence will remain in the 70s while the coastal plain drops back into the mid to upper 60s. Overall, temperatures will be fairly seasonable for the time of year.

This ridge of high pressure over New England will remain in control heading into early next week. This will keep dry weather in the picture for New England through at least Monday. Despite this, there should be plenty of clouds around for the coastal plain (after Friday) due to the moist onshore flow off the ocean. Western and northern New England will see the most sunshine during this time. It will not be persistently overcast despite the clouds.

Weather map for Sunday morning showing the ridge off the New England coast with what's left of Helene to our southwest (September 29):

Photo byWeather Prediction Center

New England's next precipitation chance will come around the middle of next week when two features may approach New England. The first will be another frontal system approaching from the west. This system may pull a developing coastal system northward at the same time.

Early indications show this coastal low strengthening to some degree as it is pulled north. The level of interaction between these systems as well as how close the coastal system will determine how much rain falls, where it falls and timing. With plenty of moisture in the atmosphere, wet weather is likely to return to some extent Tuesday into Wednesday. Another period of high pressure and ridging is looking to follow this system, but now we're getting ahead of ourselves.

Current weather map for Wednesday (October 2), showing the features described above:

Photo byWeather Prediction Center

In the tropics, Helene made landfall late last night (just before 11:15pm) as a category four storm. This brought a catastrophic storm surge, extreme winds and significant inland flooding from rainfall. As of 8am, about 3.6 million are without power across the southeast. Outages exceed 1 million in Florida, Georgia and South Carolina.

High wind warnings remain in effect from Georgia through Indiana, so these numbers will continue to fluctuate. Major flash flooding will also continue across the southern Appalachians today. Multiple flash flood emergencies remain in effect across the interior southeast, including in the Atlanta Metro area.

Flash flood warnings and emergencies as of 8am:

Photo byNational Weather Service

Elsewhere in the tropics, the coastal storm from last weekend that brought 6-12 inches of rain to Cape Cod has become Hurricane Isaac across the northern Atlantic Ocean. This storm won't affect any land and is meaningless to New England's weather (or the weather anywhere), but it's an interesting development. There are three other areas of interest in the Atlantic but none pose a threat to land at this time.

Photo byNational Hurricane Center