textproduct: Boston / Norton

WHAT HAS CHANGED

No changes to the forecast at this time.

KEY MESSAGES

- Showers and unsettled weather taper off tonight. This will be followed by dry and seasonable conditions through Wednesday night.

- Scattered showers and a few thunderstorms possible at times Thu night into Fri. We will need to watch the risk for a few severe t-storms Fri PM...But only if enough instability develops.

- A few showers may linger into Sat...otherwise dry weather dominates into early next week but will need to watch for MCS potential given northwest flow aloft. Warming trend as well, but thinking the worst of the heat may remain to our southwest.

DISCUSSION

KEY MESSAGE 1... Showers and unsettled weather taper off tonight. This will be followed by dry and seasonable conditions through Wednesday night.

Convergence along a frontal boundary extending southwest to northeast across Rhode Island and southeast MA will continue to support wet/unsettled weather through this afternoon. No widespread shower or thunderstorm activity expected, but rather some fog, low clouds, and spotty showers. May see some breaks of sunshine across interior MA and CT as some drier air works its way in behind the front. Expect the front to move offshore by tomorrow morning. This will be followed by a beautiful Wednesday with seasonable temperatures in the upper 70s to low 80s, mostly sunny skies, and light winds.

KEY MESSAGE 2...Scattered showers and a few thunderstorms possible at times Thu night into Fri. We will need to watch the risk for a few severe t-storms Fri PM...But only if enough instability develops.

The next shortwave and associated mid level warm front will approach and cross the region Thu night into early Fri. There is enough forcing along with some elevated instability for an initial round of some showers and perhaps a few thunderstorms sometime Thu night into early Fri. Uncertainty prevails at this time range on the areal coverage of any of this activity. This will be followed by a potential second round of scattered showers and a few thunderstorms Fri afternoon and evening. This potential will be determined by how much instability we can generate along with forcing along the approaching pre-frontal/cold front. The SPC SREF is showing some impressive probabilities of effective shear exceeding 40 knots Fri afternoon. However...it remains to be seen if we will have enough instability and favorable time for any severe weather. Regardless...much of the machine learning guidance indicating some low probabilities so bears watching.

KEY MESSAGE 3...A few showers may linger into Sat...otherwise dry weather dominates into early next week but will need to watch for MCS potential given northwest flow aloft. Warming trend as well, but thinking the worst of the heat may remain to our southwest.

Still some timing differences on the cold front and if another wave of low pressure impacts us Sat as the front sags southward. So there is the possibility for some lingering showers Sat if the front is on the slower side especially near the south coast. Otherwise...the main weather story for the first half of next week will be an upper level ridge of high pressure building across the Ohio Valley. This will place us in northwest flow aloft...so we will need to watch for the potential to be impacted by an MCS sometime during the first half of next week. Whether or not this occurs though will depend on where exactly the ring of fire sets up. In terms of temperatures... the GFS is quite aggressive in bringing near record heat to our region by the middle of next week. While we do expect a warming trend...thinking the GFS/CMC ensembles are more realistic keeping the worst of the heat to our southwest given lingering trough to our east over the Atlantic.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Forecaster Confidence Levels...

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

18Z Update

Through 06Z

Moderate confidence at best.

Widespread MVFR/IFR ceilings with embedded MVFR/IFR vsbys in FOG and -SHRA through 00Z. Some uncertainty with respect to timing of improvements, but likely lingering MVFR for most of the evening through about 06-08Z. Shower activity should wane after 00Z across the interior with Cape/Islands terminals experiencing showers through 06-08Z.

06Z Tonight Through Tomorrow Night

Showers exit west to east between 06-09Z tonight. This will be followed by VFR conditions, mainly clear skies, and light northerly winds through tomorrow night.

KBOS Terminal...Moderate Confidence.

Low confidence with respect to timing of ceilings rising to VFR, but most likely by 06-08Z.

KBDL Terminal...High Confidence.

Outlook /Wednesday Night through Sunday/...

Thursday: VFR.

Thursday Night: Mainly VFR, with local MVFR possible. Chance SHRA.

Friday: Mainly VFR, with local MVFR possible. Breezy. Chance SHRA, slight chance TSRA.

Friday Night: Mainly VFR, with local MVFR possible. Chance SHRA.

Saturday: VFR. Chance SHRA.

Saturday Night: VFR. Slight chance SHRA.

Sunday: VFR.

MARINE

Forecaster Confidence Levels...

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

Tonight through Tomorrow Night

Some showers and possible a rumble of thunder over the south coastal waters this evening as an area of low-pressure slowly moves east/northeast this evening. Winds are generally light through this period varying in direction with a westerly component. Sustained speeds and gusts less than 20 through tomorrow night with seas 2-4 feet.Outlook /Wednesday Night through Sunday/...

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

Thursday Night through Friday: Winds less than 25 kt. Chance of rain showers.

Friday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers, slight chance of thunderstorms.

Saturday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers.

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

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

BOX WATCHES/WARNINGS/ADVISORIES

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