BOSTON (CBS) – July is usually one of our driest and sunniest months of the year. It has the warmest average temperatures and is generally full of great days to hang out on the beach and frolic in the open ocean or in one of our many lakes.
But this July was far from typical.
In just one week, Boston has more than 5 inches of rain, the second most common rainfall from July 1-7 (just before July 1915). It rained on five of the first six days and more showers / storms are forecast for Wednesday afternoon, Thursday and Friday.
Just days after three record-breaking hot days at the end of June, we hit a high of just 60 degrees on Saturday 3rd July, a record low for the date and a tie for the lowest record high for any day in July ever recorded! So far, July has been almost five degrees below average per day, the coolest first week of July in more than a decade.
And now this one … Tropical storm Elsa will hit land along the northwest coast of Florida on Wednesday. When tropical systems migrate inland, they usually quickly lose steam and become “extratropical,” a fancy way of saying that they transform into a normal old low pressure system and lose their tropical properties.
TRACK: Tropical storm Elsa
However, Elsa has other plans. It seems like Elsa can hold a tropical storm through Georgia, South Carolina, and North Carolina through Thursday (albeit slowly weakening). 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 feed on the warm ocean and maybe even strengthen it a little as it heads towards southeast New England.
Current forecasts say Elsa will fly by somewhere between southern Plymouth County and Barnstable Counties on Friday afternoon and then speed up quickly to Nova Scotia by Friday evening.
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 MA, that would put a large part of our area in the sights of 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, this would hit the Cape and Islands 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 at a low level (just above the ground) to the surface. We have to keep a close eye on this in the next 24-48 hours in the next model predictions. 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 splash 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 be staying long … it’ll be speeding out to 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, if by no means a washout.