![]() ![]() While we elected to mention the severe threat here the, low, threat for severe weather actually appears to be greatest in the first period of the long term, after 00Z Thursday. With a tropical airmass in place, we do need to be cognizant of the "high shear/low CAPE" environment, with Bulk Shear climbing to as high as 40kt, that often generates a brief spin up tornado. Global guidance differs significantly from the CAMs that are beginning to stream in for the time period regarding instability, with the NAM highlighting 400-800J/kg MUCAPE while the GFS struggles to eclipse 200J/kg. MUCAPE values of 500- 1000J combined with modest shear of 30-35kt should be enough to initiate some strong storms/heavy downpours along the front, but severe potential will be limited by poor lapse rates of ~5C/km. PWATs of near 1.8" combined with near parallel to the front, prefrontal flow will reemphasize moisture transport into the region. Unfortunately, more substantial precipitation looks likely on Wednesday, and particularly Wednesday afternoon and early evening, as a cold front approaches from the west. It should be another mild evening, with dewpoints not really budging from the mid 60s to near 70F. Stratus and fog persist overnight in areas that never truly cleared during the day on Tuesday, while fog redevelops across the CT River Valley resulting in a rather dreary September night for all of southern New England. SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/ Thus, with more sunshine and a more favorable wind direction, expecting a rather significant, as much as 10F, temperature gradient to set up across the region, with the CT River Valley reaching towards 80F and northeastern MA struggling to climb into the low 70s dewpoints in the high 60s to low 70s acting as a lower bound for temps. HRRR members suggest that these showers will be much less impactful than day's past, with less that 0.1" of QPF expected.Ġ0Z guidance overnight was quite bullish in sectoring out the Connecticut River Valley as the exception to the rule today, where breaks of sunshine and much higher cloud bases develop as light winds shift to the southwest this afternoon. In addition to the clouds, weak orographic forcing given easterly flow will likely be enough to initiate some scattered showers across eastern MA and RI this afternoon. Interior eastern MA can expect to see some improvement in visibility by 17Z. This cloud deck will also inhibit the mixing out of fog and drizzle across the same area, such that the fog may never actually clear out of coastal zones this afternoon. Primarily E/NE flow across eastern MA and RI will help pin low clouds up against the Worcester Hills, resulting in widespread stratus from Worcester, east for the entirety of the day. While precipitation will be greatly reduced this afternoon, this shift in the low's position won't bring abundant sunshine to most of the region. The stationary front and associated low pressure that brought a deluge of precipitation to southern New England over the past few days finally relinquishes it's grasp as the weak low pulls out to sea. Refer to the latest forecasts on Hurricane Lee from the National Hurricane Center. Increasing surf and rip currents are likely to begin around Tuesday and continue into the weekend, although there is low confidence in any other impacts. Much drier and more seasonable weather then arrives for Thursday into at least Friday, although Hurricane Lee still could make a closer pass late this week or next weekend. Scattered showers possible Tuesday before a frontal system interacting with subtropical moisture brings soaking rains to parts of southern New England Wednesday. Individual wave heights may be more than twice the significant wave height.Īrea Forecast Discussion National Weather Service Boston/Norton MA 349 AM EDT Tue Sep 12 2023 Seas are reported as significant wave height, which is the average of the highest third of the waves. ![]() Sat night.NW winds 20 to 25 kt with gusts up to 35 kt. Sat.N winds 20 to 25 kt with gusts up to 40 kt. Waves 2 to 3 ft, increasing to 3 to 5 ft in the afternoon.įri night.N winds 10 to 15 kt, increasing to 15 to 20 kt after midnight. Waves around 2 ft.įri.N winds 10 to 15 kt with gusts up to 20 kt. Wed night.S winds 5 to 10 kt, becoming W after midnight. Patchy fog in the morning with vsby 1 to 3 nm. Vsby 1 nm or less, increasing to 1 to 3 nm this afternoon. A chance of showers, mainly this morning. ANZ230 Boston Harbor- 401 Am Edt Tue Sep 12 2023 ![]()
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