DAYS 1-5 (SEPTEMBER 26-30)

Discussion…

We’ll have a warmer than normal but more humid weekend, however it will remain rain-free. It won’t, however, remain fog-free for a large portion of the region, especially this morning and again later tonight into Sunday morning. This is one of the results of an increase in humidity. With a mostly clear sky above, the warmth from the day radiates out to space and as the air temperature drops to match the dew point temperature, fog forms, and can be rather dense as it is in some places to start the day today. But the same clear sky that played a role in helping the fog form will also play a role in its dissipation, as the sun rises higher into the sky and shines into the foggy areas, warming the air up, and eventually evaporating the fog. A generally sunny midday and afternoon will be the result today over southern NH and a good portion of MA, but there are already some clouds moving into the South Coast region and those will limit sunshine there today. These clouds make some advance tonight and we also see more fog patches forming which will burn off to a partly sunny to mostly cloudy sky on Sunday. But even with that, still not really a bad weekend for this area. Things change as we start the new week and go through the last 3 days of September. As previously mentioned, high pressure will have shifted offshore and a larger scale upper level trough will be forming west to New England, gradually moving to the east. A slow-moving cold front will approach and eventually enter the region, finally pulling through during Wednesday. While at days 3, 4, and 5 I still can’t time showery periods and drier periods, I can say that the best highest risk for the most widespread shower activity, based on current timing, looks like Tuesday night to early Wednesday.

Details…

TODAY: Large areas of fog and low clouds to start, burning off by late morning to a mostly sunny sky except partly to mostly cloudy South Coast. Highs 74-81.Dew point rising to around 60. Wind S increasing to 5-15 MPH.

TONIGHT: Partly to mostly cloudy. Areas of fog. Lows 57-64. Dew point near 60. Wind S under 10 MPH.

SUNDAY: Areas of fog early. Mostly cloudy to partly sunny. Highs 75-82. Dew point above 60. Wind S 5-15 MPH.

SUNDAY NIGHT: Mostly cloudy. Areas of fog. Lows 58-65 Dew point upper 50s to lower 60s. Wind S 5-15 MPH.

MONDAY: Variably cloudy. Chance of showers. Highs 70-77. Dew point in 60s. Wind S 10-20 MPH.

MONDAY NIGHT: Mostly cloudy. Areas of fog. Chance of showers. Lows 60-67. Dew point in 60s. Wind S 5-15 MPH.

TUESDAY: Variably cloudy. Chance of showers. Highs 70-77. Dew point in 60s. Wind S 10-20 MPH.

TUESDAY NIGHT: Cloudy. Showers likely. Areas of fog. Lows 60-67. Dew point lower 60s. Wind S 5-15 MPH, higher gusts.

WEDNESDAY: Cloudy start with showers likely and areas of fog, then partly sunny with scattered showers. Highs 70-77. Dew point starting in 60s then falling to 50s. Wind SW 10-20 MPH shifting to W with higher gusts possible.

DAYS 6-10 (OCTOBER 1-5)

Model guidance will struggle with development of additional low pressure near the East Coast. While some guidance has additional rain October 1 other guidance is dry. Varying guidance has varying solutions for the first several days of October. With this in mind, the best bet is to leave this portion of the forecast very general in that we’ll turn somewhat cooler and there may be additional opportunities for unsettled weather, still leaning toward October 2 & 4.

DAYS 11-15 (OCTOBER 6-10)

Zonal flow expected but mean trough may hang in the Great Lakes region. This would be a drier trend but not absent of at least brief rainfall threats. Temperatures would be variable but average fairly close to normal.