textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes to the forecast.

KEY MESSAGES

- More seasonable temperatures, dry weather and comfortable humidities through Tuesday night. Scattered pop-up showers in far western New England later Wednesday afternoon.

- High astronomical tides with less than a foot of storm surge could cause minor coastal flooding for the evening high tides tonight and Tuesday night.

- Gusty southerly winds with some showers and perhaps a few t-storms on Thursday. Watching the severe weather potential too...But right now thinking main threat will be to our southwest.

- Beautiful stretch of weather Fri through Mon with warm afternoon/s with highs generally between 75 and 85 with comfortable humidity.

DISCUSSION

KEY MESSAGE 1...More seasonable temperatures, dry weather and comfortable humidities through Tuesday night. Scattered pop-up showers in far western New England later Wednesday afternoon.

Cyclonic flow aloft will govern Southern New England's weather through Tuesday, and with it will brings a more refreshing Canadian airmass. Cool advection tonight and Tuesday brings 850 mb temps around +6 to +9C, which is about 4-6C cooler than we saw over the weekend when temperatures reached into the mid 80s to lower 90s. Full sun, decreasing NW breezes tonight shifting to lighter W breezes Tuesday, with seasonable temperatures in the 70s to low 80s, with lows tonight and Tuesday night in the low to mid 50s. Dewpoints in the upper 40s to mid 50s, so humidity levels are low. All in all, really nice weather for mid-June!

Into Wednesday...a more modest warm advection pattern develops ahead of a disturbance aloft moving through the Great Lakes and into northern New England. Although most of the day ends up dry, increasing clouds with scattered showers develop into western New England, mainly from Worcester to Willimantic westward and better shot into the Berkshires. Instability looks lacking for a robust thunder threat in these showers but couldn't rule out a rumble of thunder in those locations. Highs top out in the upper 70s to lower 80s, with dewpoints a touch higher but should still be comfortable.

KEY MESSAGE 2...High astronomical tides with less than a foot of storm surge could cause minor coastal flooding for the evening high tides tonight and Tuesday night.

Astronomical tides will be building to their highest level tonight Monday, peaking around 12.0 ft at Boston Harbor Monday evening, but remaining elevated into Tuesday night. Forecast storm surge from Stevens Institute and P-ETSS guidance suggests values around 0.5 to 0.7 feet tonight and Tuesday night. With hardly any wave action, forecast total water level should be pretty similar to recent days. Coastal Flood Statements continue for the southern and eastern coasts for very minor tidal flooding into Tuesday night. We may be able to get away with a Coastal Flood Statement vs an Advisory for Nantucket for the Tuesday evening high tide, but will give later shifts an opportunity to reassess that. The evening high tide cycles tonight and Tuesday night are the periods we are most concerned for, as those high tide magnitudes are higher.

This remains a low-ceiling/low-impact coastal flooding scenario, with splashover or at worst minor coastal flooding in the usual vulnerable shoreline roads (including but not limited to Easy Street in Nantucket and Morrissey Blvd in Boston). However we'll carry these headlines for more awareness, given that there are more visitors to Southern New England who may not be as familiar with coastal/tidal flooding.

KEY MESSAGE 3...Gusty southerly winds with some showers and perhaps a few t-storms on Thursday. Watching the severe weather potential too...But right now thinking main threat will be to our southwest.

Low pressure tracking northeast across Quebec will allow a pre- frontal trough/cold front to approach our region from the west on Thursday. Ahead of these features a modest southwest LLJ of 45 to 55 knots will develop. This coupled with mixing will result in gusty southerly winds of 25 to 35 mph developing. High temperatures probably top out in the upper 70s to the middle 80s in most locales.

We do expect some showers to impact the region very late Wed night into the first half of Thu morning with a warm front crossing the region. Then we may see another round of scattered showers and perhaps a few t-storms Thu afternoon/evening with the actual cold front/shortwave. We will need to watch the risk for severe weather too given strong wind fields...But right now thinking that the main risk for this looks to be to our southwest where better instability resides.

KEY MESSAGE 4...Beautiful stretch of weather Fri through Mon with warm afternoon/s with highs generally between 75 and 85 with comfortable humidity.

Two closed upper level lows just south of Hudsons Bay will result in height fields lower than normal Friday into the weekend across the northeast. This will suppress deeper moisture to our south and result in a beautiful stretch of weather. High temps will generally be between 75 and 85 with comfortable humidity. Overnight low temps will mainly be in the 50s to the lower 60s.

Generally dry weather is on tap over this time period too. Some northern stream energy may result in a few brief diurnally driven spot showers...But for the most part dry weather is expected.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

Forecaster Confidence Levels...

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

00z TAF Update...

Tonight...High confidence.

VFR. NW winds gradually diminishing.

Tuesday and Tuesday Night...

VFR. NW/W winds less than 10 kts. Tuesday offers a better chance for seabreezes, but would be late in the day (after 19z/20z). Winds become light and/or calm SW.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Wednesday through Saturday/...

Wednesday: VFR.

Wednesday Night: VFR. Chance SHRA.

Thursday: Mainly VFR, with local MVFR possible. Windy with local gusts up to 30 kt. Chance SHRA, isolated TSRA.

Thursday Night: Mainly VFR, with local MVFR possible. Breezy. Slight chance SHRA.

Juneteenth through Friday Night: VFR. Breezy. Slight chance SHRA.

Saturday: VFR. Breezy.

MARINE

Forecaster Confidence Levels...

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

Through Tuesday Night: High confidence.

Winds and seas to remain below small craft advisory criterion through Tuesday night. NW winds this afternoon around 15-20 kt to subside to around 10-15 kt overnight. Winds then shift to W around 10-15 kt Tuesday, coming around to southerly Tuesday night. Seas to remain around 4 ft or less on all waters.

Outlook /Tuesday Night through Saturday/...

Wednesday: Winds less than 25 kt. Slight chance of rain showers.

Wednesday Night: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers.

Thursday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft. Chance of rain showers.

Thursday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 9 ft. Chance of rain showers.

Juneteenth: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Chance of rain showers.

Friday Night: Winds less than 25 kt. Areas of rough seas. Chance of rain showers.

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

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...Coastal Flood Advisory until 2 AM EDT Tuesday for MAZ024. RI...None. MARINE...None.