textproduct: Boston / Norton

WHAT HAS CHANGED

No changes to the forecast for this update cycle.

KEY MESSAGES

- Dry and comfortable weather continues for the second half of the weekend into Monday.

- Heat and humidity return midweek with possible heat headlines Tuesday and Wednesday.

- Periods of unsettled weather possible later this week as an upper level trough pushes over the region.

DISCUSSION

KEY MESSAGE 1...Dry and comfortable weather continues for the second half of the weekend into Monday.

Surface analysis shows a large area of high pressure over the Northeast this afternoon. Comfortable weather will continue today with highs in the low 80s and low humidity. The high will slowly move off the coast through Monday. A return flow will bring warmer weather and higher dewpoints into the region Monday. While not as hot as expected heat Tue/Wed, heat indices are expected to reach the upper 80s to low 90s.

A weak shortwave trough is expected to move across northern New England Monday afternoon through evening. The combination of increasing dewpoints, surface heating, and increasing lift may support a few showers across northern MA which is in agreement with the HREF.

KEY MESSAGE 2...Heat and humidity return midweek with possible heat headlines Tuesday and Wednesday.

A 599dam mid-level high pressure system will remain over the Central U.S. with ridging extending into the Mid-Atlantic and portions of New England through mid week. LREF show 850mb temps rising to +22-23C, which is near the 97-99th percentile for this time of year and will translate to surface temperatures in the mid 90s to perhaps upper 90s across all but the immediate south coasts, Cape Cod and the Islands Tuesday and Wednesday. Combined with dew points rising into the mid and upper 60s, this will result in heat indices of 95 to 105, which may necessitate heat headlines in subsequent forecast updates as confidence continues to increase. We may also approach daily heat records in a few locations during the afternoon highs or even morning lows with very little recovery overnight. While not as intense as the previous stretch of hot weather, temperatures of this magnitude will still present significant risks for those working or doing recreation outdoors. Rain chances will remain very low with exception to an isolated diurnal seabreeze shower.

KEY MESSAGE 3...Periods of unsettled weather possible later this week as an upper level trough pushes over the region.

Models continue to show an amplifying upper-level trough over Quebec for the second half of next week. The trough will serve to suppress the ridge and cool 850 temps to +10-13C. These values translate to highs in the mid lower to mid 80s by Friday. A series of shortwave disturbances rotating around the periphery of the trough bring chances for precipitation and unsettled weather by the end of the week and potentially into next weekend.

AVIATION /19Z SUNDAY THROUGH FRIDAY/

Forecaster Confidence Levels...

Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.

Through Monday Night: High Confidence.

VFR. A seabreeze will continue to move westward across eastern MA today. Variable winds expected overnight. A southwest wind increases across the region Monday.

KBOS Terminal...High Confidence.

KBDL Terminal...High confidence.

Outlook /Tuesday through Friday/...

Tuesday: VFR. Windy with areas of gusts up to 30 kt.

Tuesday Night: VFR. Windy with local gusts up to 30 kt.

Wednesday: VFR. Breezy.

Wednesday Night: VFR.

Thursday: VFR. Breezy.

Thursday Night through Friday: VFR.

MARINE

Forecaster Confidence Levels...

Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.

Through Monday...High confidence.

Light winds will continue through tonight. High pressure moves off the coast early this work week. Southwest winds will increase across the coastal waters and SCA conditions will likely be met Tuesday. Best chance will be in the near coastal waters of SE MA including Buzzard's Bay.

Outlook /Tuesday through Friday/...

Tuesday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft.

Tuesday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 8 ft.

Wednesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas.

Wednesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers.

Thursday through Friday: Winds less than 25 kt.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...None.