BOSTON (CBS) – With Tropical Storm Elsa moving up the east coast, warnings were issued Thursday by the National Weather Service covering parts of southern New England. The warnings were issued as far north as the Merrimack River and include the Boston and Providence areas.
TRACK: Tropical storm Elsa
Elsa left South Carolina Thursday morning. On Friday it will reach the warm coasts of the Central Atlantic near the Delmarva and will be revived.
During the day on Friday, it will be nourished and perhaps even strengthened by the warm ocean as it travels towards Southeast New England, where it should be from morning to mid-afternoon.
So what could that mean for us?
The biggest threat to Elsa here in southern New England appears to be heavy rains. A tropical system like this can do a blow with torrential downpours that can cause flooding in a very short time. And considering how much rain our area has received over the past 5-6 days, local flooding concerns are slightly higher than average. It’s not ruled out that some areas could receive several inches of rain on Friday in a 6-12 hour window of heavy bands lined up.
The location of these heavy rain bands is highly dependent on the exact trace of Elsa, but usually occurs north and west of the trace of the center. With the current forecast over southeast Massachusetts, that would put a large part of our area in the sights of the rain on Friday.
The winds are also an issue on Friday, but this is a much bigger wild card than the rain. The strongest winds are typically on the east side of a tropical system (right of center). Given the current forecast, the Cape and Islands would hit the mark on Friday for southerly gusts of 30 to 50 mph.
There is a small (but not yet ruled out) risk of even stronger gusts (perhaps over 60 miles per hour) if the jet stream mixes up to the surface at low altitude (just above the ground). We have to keep a close eye on this in the next model predictions over the next 24 hours. The further north and west of the Elsa route you go, the lower the risk of wind.
Floods in southern New England occur around noon / early afternoon on Friday. Given the prevailing wind direction from the south or southeast, the main concern would be for splashes or flooding along the south coast of Cape Cod, Martha’s Vineyard, and Nantucket. There are no warnings at this point, but that could change as we get closer to the event.
The good news is, Elsa won’t stay long. It’ll be speeding at sea and be in Nova Scotia by Friday night. We should see a quick cleanup late in the day on Friday, preparing us for a quieter weekend. At the moment, Sunday seems to be the choice as sunshine and low 80s are expected, there may be a few isolated showers on Saturday, albeit by no means a washout.