Rainy day for New England today as Helene bears down on south

An area of low pressure will be passing to New England's north today. This will drag its fronts across the region, leading to a very wet day and evening for the region. As expected, a bout of rain has broken out across northern New England this morning. The rainfall will generally stay in northern New England through much of the morning before expanding southward later in the day.

Later today, a triple point low (the triple point in a system is the point where a warm, cold and occluded front meet) is expected to form over New England. The highest rainfall rates will be associated with this low as moisture becomes focused over it. This will come as tropical-like moisture is working up the east coast.

Photo byNew England Storm Center

All of that is to say today will be a rainy day in New England. Rain will be focused primarily across northern New England (except for a few wayward showers dropping south) until later in the afternoon when the shield of more widespread rain expands southward as the triple point low forms. Heading into the evening, the system's cold front will cut through New England from northwest to southeast. A fine line of downpours looks to develop this evening and pass through southern New England this evening into the first part of the night.

Potential weather around mid-afternoon today (1st image) and later this evening (2nd image):

Photo byHRRR/Tropical Tidbits

Photo byWRF-ARW/Tropical Tidbits

An additional half inch to inch of rain is likely in southern New England with another inch to inch and a half in northern areas. The center of the system will likely linger around northern Maine/Nova Scotia through Friday as high pressure builds into western New England. Despite this, the day may end up mainly cloudy. Scattered afternoon showers will be possible across the northern third of the region due to wrap around activity.

Photo byNew England Storm Center

On the tropical front, Hurricane Helene will continue to strengthen today as it moves north-northeast in the Gulf of Mexico. The storm will likely reach either category three or four strength before making landfall near Florida's big bend region. This storm's legacy will likely be from major flooding, both coastal storm surge and inland. Storm surge around Florida's Big Bend may top out at 12-15+ feet. A storm surge up to five feet is possible across all of Florida's west coast.

Photo byNational Hurricane Center

As for inland flooding, much of the south could see 3-7 inches of rain with some areas seeing 5-10 inches. The area of greatest concern will be the southern Appalachian Mountains, where runoff from the mountains will result in a major flooding event. Flood warnings and flash flood warnings remain ongoing in this area as of Thursday morning. Flood watches remain in effect through Friday evening.

Weather Prediction Center 2 day rainfall forecast:

Photo byWeather Prediction Center

This will come as the storm bends to the west and slows down as it runs into a blocking high to the north. The storm will linger around the south and Mississippi Valley through the weekend as it weakens. Tropical Storm Warnings extend as far inland as the North Carolina-Tennessee border. The blocking high over New England will keep the remnants to the south and west.

Photo byNational Hurricane Center

Elsewhere in the tropics, the coastal storm that brought 6-12 inches of rain to Cape Cod late last week has continued to drift through the Atlantic. The storm has taken on tropical characteristics and has actually formed into Tropical Storm Isaac. The storm will continue to drift through the northern Atlantic and is completely meaningless in regards to the weather anywhere, but it's an interesting development regardless. Another disturbance moving west across the open Atlantic has an 80% chance of development, but poses no threat to land.

Photo byNational Hurricane Center

Back to New England, once today's spattering of rain moves out, high pressure will generally be in control through early next week. This high pressure will be the one blocking Helene's remnants into the south. New England's next chance at precipitation will come around midweek when another frontal system may approach. Also, the remnants of Helene could spawn a coastal low to the south of New England during this time. The details on what this setup will bring will come with time as always.

Current weather map for Wednesday (October 2):

Photo byWeather Prediction Center