textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes to the forecast.

KEY MESSAGES

- A few scattered showers possible both this afternoon and Tuesday afternoon. Tuesday begins a pattern of steadily climbing temperatures each day through the week.

- Forecast confidence decreases for late this week. Conditions more likely to be dry and warm, but we continue to monitor the potential for an offshore system to bring showers this weekend.

DISCUSSION

KEY MESSAGE 1...A few scattered showers possible both this afternoon and Tuesday afternoon. Tuesday begins a pattern of steadily climbing temperatures each day through the week.

The synoptic pattern continues to feature a broad upper trough lingering over the Northeast with the associated cold pool leading to widespread diurnal cloudcover over inland areas, and even some decent pop-up shower coverage over western and central SNE. This activity will continue through sundown when skies quickly clear setting up for a good radiational cooling night. Given building surface high pressure leading to calm winds and clear skies overnight, the forecast has been trended toward the cooler MOS guidance. We're expecting lows in the upper 30s/low 40s in the typical cold spots, closer to 50 in the urban centers.

Tuesday features a transition from the broader trough we've dealt with the last several days to a building mid level ridge. As such, we expect warm advection and clear to mostly sunny skies to lead to highs well into the 70s. That being said, a weak disturbance rounding the base of the exiting trough will be enough to once again kick off a few diurnal showers and even a thunderstorm given a few hundred J/kg of elevated CAPE. Expect the most sun in the morning before low level diurnal clouds and some mid/high clouds filter in in the afternoon.

KEY MESSAGE 2...Forecast confidence decreases for late this week. Conditions more likely to be dry and warm, but we continue to monitor the potential for an offshore system to bring showers this weekend.

Mid level omega block expected to start breaking down Wednesday into Friday. The mid level flow at that point should remain rather amplified for an early meteorological summer pattern. There are significant timing differences in how short this breakdown process will be, which is not all that unusual. These details matter, and will take a more probabilistic approach with the forecast from Wednesday on.

Overall, it appears that southern New England finally edges more into the higher heights part of the block around Wednesday, with a surface high pressure over the Great Lakes. Expecting dry weather with warmer conditions Wednesday into Friday.

The forecast this weekend into early next week is more problematic. Much will depend on how quickly the aforementioned omega block breaks. At this time, there is a chance that we remain dry for most of the day Saturday. However, there are also enough signals where a mention of scattered afternoon showers is warranted. A low pressure passing by along a nearly stalled front for Sunday is a more favorable pattern for showers. This front could linger into Monday, continuing the risk for some showers.

Temperatures should start to lower Saturday, but the cooldown is anticipated to be more noticeable Sunday into Monday.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

Forecaster Confidence Levels...

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

Tonight...High Confidence.

VFR. Light to calm winds.

Tuesday...High Confidence.

VFR. NE 5-10 kts for inland terminals with sea breezes along the coast.

KBOS...High confidence in TAF.

KBDL...High confidence in TAF.

Outlook /Wednesday through Saturday/...

Wednesday through Thursday Night: VFR.

Friday: VFR. Breezy.

Friday Night through Saturday: VFR.

MARINE

Forecaster Confidence Levels...

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

Through Tuesday Night...High Confidence.

NE winds 5-10 kts this afternoon become light and variable overnight. Winds then increase Tuesday, 5-10 kts out of the SW. Seas generally 3-4 ft this afternoon will continue to decrease becoming 1-3 ft overnight and continuing through at least mid week.

Outlook /Wednesday through Saturday/...

Wednesday: Winds less than 25 kt.

Wednesday Night: Winds less than 25 kt. Seas locally approaching 5 ft.

Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft.

Thursday Night through Saturday: Winds less than 25 kt. Seas up to 5 ft.

BOX WATCHES/WARNINGS/ADVISORIES

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