9:28AM
DAYS 1-5 (SEPTEMBER 30-OCTOBER 4)
An interesting final day of September. I saw a hint of the mesoscale event that brought flooding rain to the Lynn and Salem MA area all the way back last night at 10:30PM, when I let a helium balloon go here in Woburn under a calm wind, and as soon as the balloon got about 100 feet into the air it started to move fairly quickly to the north, indicating a south wind. Earlier the wind had been blowing from the northwest and as it eased up a sea breeze had formed along the coast of NH and northeastern MA. This light northeast flow was still in place there this morning while a more southerly flow had been established not too far to the southwest of this area. As the potent disturbance arrived on schedule with very cold air aloft over relative warmth at the surface (both land and ocean), it combined with the boundary and helped force a relatively small but slow-moving area of heavy rain and some thunder. The torrential rain resulted in localized flooding and since then (as of the writing of this) had progressed southward into Boston Harbor and is heading into the South Shore and southern suburbs now. The best dynamics for this type of event will be shifting south during the day as the entire disturbance does so, but anywhere in the region can experience showers for several hours before a drying trend takes place from north to south later in the day and by evening. Looking forward, the forecast gets much more simple for the first 4 days of October as high pressure re-establishes control, and we transition from a chilly start to a return of a summer feel by the end of the period.
TODAY: Mainly cloudy through early afternoon with area of shower, some heavy, especially eastern MA, including a risk of thunder and even some graupel mixed with the rain. A drying trend from north to south later in the day with some partial clearing especially north. Temperatures holding in the 50s. Wind variable 5-15 MPH.
TONIGHT: Clearing. Patchy frost interior valleys mainly central MA and southern NH. Areas of ground fog. Lows 38-43 interior, 44-49 coast. Wind N under 10 MPH.
SUNDAY: Sunny to partly cloudy. Highs 63-68. Wind N 5-15 MPH.
SUNDAY NIGHT: Clear. Lows 40-45 interior, 45-50 coast. Wind light variable.
MONDAY: Sunny. Highs 63-68 coast, 68-73 interior. Wind light variable with sea breezes.
TUESDAY: Sunny. Lows from the middle 40s to middle 50s. Highs from the upper 60s to middle 70s coast, middle to upper 70s interior.
WEDNESDAY: Sunny. Lows in the 50s. Highs in the 70s to lower 80s, coolest coast.
DAYS 6-10 (OCTOBER 5-9)
A cold front will come through from north to south by early October 6 but not before one more very warm day October 5. Limited moisture with the front so maybe a few showers early October 6 then a return to dry weather and although it will cool down somewhat, temperatures will still run above normal.
DAYS 11-15 (OCTOBER 10-14)
Better opportunity for rain toward the end of the period after fair and mild weather to start it.