Although a few showers will fall in New England Wednesday, rain won’t be the feature of the day. Rather, showers will remain isolated to widely scattered, mostly developing in Central, Western and Northern New England, and will tend to wane toward evening. The showers are developing from south to north as a tangible change in air arrives, with increasing humidity indicated by a rise in dew points to the middle and upper 60s, feeling more like summer as astronomical fall begins at 3:21 PM Wednesday afternoon. Slow-moving bands of rain and thunder across the Ohio Valley and Great Lakes will remain sluggish, marking time Thursday so most of the day in New England brings only a few showers or a thunderstorm, particularly during the afternoon, but the vast majority of New England sees far more dry time than wet with some breaks of sun, continued humidity and high temperatures near 80° making for a summer feeling. The cold front slowly prodding east into warmth and humidity, overturning that air for periodic showers, rain and thunder, arrives to New England Friday for an unsettled finish to the week and while the actual number of hours spent raining may again be a bit limited, the tropical humidity feeding these storms raises the potential for locally torrential downpours and perhaps even a few damaging storms depending on the exact timing of the cold front’s arrival. The concern is with this cold front moving so slowly, showers or rain may very well linger into Saturday, particularly in the morning and particularly in Eastern New England – this possibility has grown in the last couple of days as the forecast speed of the cold front has continued to decrease and our exclusive, built-in-house NBC Forecast System has increased from a 20% chance of Saturday showers early in the week, to a 50-60% chance as of this Wednesday writing. So…while from three days out we still need to work on the finer details like exactly what time the showers will end, from this vantage point is seems like Sunday surely should be the pick of the weekend. Once nicer weather arrives Sunday, the pleasant air sticks around for most of next week with the early call for dry conditions with the exception of one midweek disturbance that will elevate the chance of showers around next Wednesday in our exclusive First Alert 10-day forecast.
The Harvest Moon reaches its fullest Monday evening, shortly after rising at 7:05 PM in a clear sky. With a large dome of high pressure – fair weather – anchored over the Northeast, not only does dry air make for a clear sky, but it’s also made for some cool overnights and Monday night beneath the Harvest Moon will continue that trend, with widespread low temperatures in the 40s. Of all our full moons in the course of a year, the Harvest Moon ranks among the most beloved we hear from our viewers about and that makes sense – it has a long, proud history in New England. The name, however, depends on what thread of history one chooses to pull. For instance, the “Harvest Moon” is believed to have originated in Europe as farmers harvested their crops toward the end of the growing season, but there was probably a bit more to it – usually the full moon rises nearly an hour later with each passing night, but this time of the year, that night-to-night lag slows a bit…moonrise Sunday evening was 6:41 PM, for example, full moonrise Monday evening is 7:05 PM and moonrise Tuesday evening will be 7:26 PM, providing a bit more consistency to the moonlight cast upon fields ready for harvest. Here in New England, The Farmer’s Almanac notes the Native American name for this moon was the Corn Moon, likely for a similar reason that corn was harvested at this time of the year. In short, the Harvest Moon – or Corn Moon – has been a pivotal moon across the Northern Hemisphere for hundreds of years – likely much more than that – providing extra light for continued work at a time of year people across the Hemisphere need it, and would have needed it even more prior to the advent of electric lights, ahead of the onset of the frost season.
On the heels of Monday evening’s Corn Moon comes Wednesday’s Autumnal Equinox – the “official” start of fall. Wednesday at 3:21 PM ET marks the start of the new season, but what exactly does this mean? In the world of meteorology, we define fall as September, October and November – starting on September 1 – but astronomical autumn follows the mark of the equinox. Observed in both the spring and fall, the equinox marks the moment when the sun is exactly above the Equator, directly overhead there in the noon sky. The practical effect of the autumn equinox here at home in New England is more rapidly and noticeably decreasing day length, with daylight dropping at a rate of nearly 3 minutes per day, dropping below 12 hours on September 26 and continuing to decline until our shortest day this coming December 21 with 9 hours, 4 minutes and 35 seconds of daylight. Of course, our New England average temperature also drops in response to the loss of daylight, with high temperatures in someplace like Boston dropping a degree every three of four days until slowing at the start of December.