DAYS 1-5 (SEPTEMBER 1-5)
September starts off with a warm and moderately humid air mass in place. A trough can kick off a shower or thunderstorm in a few places from midday to late afternoon mainly from the I-90 belt southward. A cold front will cross the area tonight but it looks like any convective activity associated with it will largely diminish / dissipate before entering the WHW forecast area, other than maybe a stray shower or storm in southwestern NH or central MA sometime this evening. The front moves offshore by morning, and high pressure will build into the Great Lakes, delivering a cooler, dry air mass. Some clouds will pop up during the day Monday in response to a pool of colder air aloft, but not enough to result in any showers. High pressure will dominate with pleasant weather, chilly nights and mild days, Tuesday through Thursday. This pattern can result in late night and early morning fog patches over lower elevation locations where the temperature and dew point have the greatest chance of matching up, but any fog of this type tends to dissipate quickly as the sun climbs into the morning sky.
TODAY: Variably cloudy. Passing showers and a slight chance of a thunderstorm, favoring I-90 southward, midday through mid afternoon. Highs 75-82. Dew point middle to upper 60s. Wind SW 5-15 MPH.
TONIGHT: Variably cloudy evening with a slight chance of a shower or thunderstorm early mainly west of I-495 and north of I-90, then clearing. Lows 52-59. Dew point falling to near 50. Wind NW 5-15 MPH.
MONDAY (LABOR DAY): Sun and passing clouds. Highs 68-75. Dew point falling into 40s. Wind NW 5-15 MPH, a few higher gusts.
MONDAY NIGHT: Clear. A patch of ground fog possible in lowest elevations. Lows 47-54, mildest urban centers. Dew point in 40s. Wind NW up to 10 MPH.
TUESDAY: Sunny. Highs 68-75. Dew point in 40s. Wind W up to 10 MPH.
TUESDAY NIGHT: Clear. Ground fog patches possible. Lows ranging from near 40 interior valleys to 50-55 urban areas. Dew point in 40s. Wind calm.
WEDNESDAY: Sunny. Highs 70-77. Dew point in 40s. Wind W up to 10 MPH.
WEDNESDAY NIGHT: Clear. Ground fog patches possible. Lows 43-50 except milder urban centers. Dew point lower to middle 40s. Wind W under 10 MPH.
THURSDAY: Sunny. Highs 71-78. Dew point in 50s. Wind W up to 10 MPH.
DAYS 6-10 (SEPTEMBER 6-10)
Higher humidity returns late next week. What remains to be seen is whether or not there will be enough interaction between low pressure to the south and a trough from the west to bring a more significant rain chance into the region into the weekend. A lot of uncertainty in this outlook, so a lot of analysis, tweaking, and fine-tuning to come. The weather follow that period will be somewhat dependent on what happens during that period. A drier scenario would likely mean there was enough blocking high pressure to hold the next system up so that we’d have a shot at unsettled weather later in the period, while a wetter scenario early in the period would more likely lead to a period of fair weather for late period. The forecast method here is not just choosing a model and going with it.
DAYS 11-15 (SEPTEMBER 11-15)
Quick look at the mid September pattern still looks fairly quiet and may turn quite warm for a period of time, but re-evaluation needed based on what takes place before that.