textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes to the forecast.

KEY MESSAGES

- Mainly dry weather continues through most of Sunday, with an increasing risk for showers Sunday night. Near normal temperatures through Sunday night.

- Unseasonably warm, June-like conditions are expected next week with highs mainly in the 70s to lower 80s, though confidence is tempered by uncertainty in a potential backdoor cold front. Otherwise, mainly dry with only isolated showers and a period of gusty southwest winds Monday.

DISCUSSION

KEY MESSAGE 1...Mainly dry weather continues through most of Sunday, with an increasing risk for showers Sunday night. Near normal temperatures through Sunday night.

Dry weather continues through most of Sunday as high pressure moves across our region tonight, then farther east over the North Atlantic Sunday night. Light winds tonight will mean decent radiational cooling conditions, much will depend on how quickly winds diminish. Much less wind Sunday will lead to near normal high temperatures. For the immediate coastal areas, will have to contend with seabreezes. Thus, the high temperature for the day could be rather late in the day along the coast, and not really last all that long prior to sunset.

An approaching warm front and a modest midlevel shortwave may combine to trigger some showers late Sunday into Sunday night. There is not a tremendous amount of moisture for this system to work with, so not expecting more than a few hundredths of rainfall. The greatest risk remains north of the Mass Pike, and especially towards the northern MA border into northern New England. This is just due to proximity to the passing mid level shortwave. Any showers are expected to quickly diminish/depart or region late Sunday night.

KEY MESSAGE 2...Unseasonably warm, June-like conditions are expected next week with highs mainly in the 70s to lower 80s, though confidence is tempered by uncertainty in a potential backdoor cold front. Otherwise, mainly dry with only isolated showers and a period of gusty southwest winds Monday.

As advertised, summer-like weather is on the horizon as a strong subtropical ridge builds across the Gulf. This will support southwest flow, advecting higher moisture and temperatures into southern New England through the upcoming week. Temperatures are expected to be more indicative of early to mid- June rather than early to mid-April.

That said, there are potential forecast challenges that could lead to notable busts in temperatures, primarily related to a possible backdoor cold front. There remains considerable uncertainty regarding its timing and placement, which is not uncommon at this lead time. Confidence should improve as higher-resolution guidance resolves this feature. Ensemble guidance highlights the uncertainty, with spreads between the minimum and maximum temperatures on the order of 20-25 degrees. This reflects the sensitivity of the backdoor cold front. For now, expect highs generally well in the 70s through the week, with a few days potentially reaching the lower 80s. The warmest temperatures will likely occur across western portions of southern New England, while the eastern areas have the greatest potential to be impacts by the cooler marine air. Overnight lows will remain mild, generally in the mid-50s to lower 60s.

In terms of sensible weather, no significant synoptic systems are on the horizon for the coming week. However, with elevated PWATs, even weak forcing may be enough to generate a few isolated showers or a rumble of thunder at times. No widespread or washout rainfall is anticipated.

On Monday, offshore high pressure and low pressure passing through eastern Canada will tighten the pressure gradient, increasing southwest flow. Expect increasing clouds and moisture. A robust low-level jet will be present, with gusts of 20-30 knots possible depending on the mixing depth of the boundary layer. Despite limited rainfall, elevated fire weather concerns may develop Monday afternoon due to gusty winds and dry antecedent conditions. Minimum RH values range from 45-60 percent inland and 70+ percent along the coast. May need to coordinate with state partners on a possible Special Weather Statement.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Forecaster Confidence Levels...

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

High confidence.

VFR conditions into Sunday Night. Areas MVFR in -SHRA Sunday Night. Gusty northwest winds diminish tonight, becoming light/calm and then shift to the S-SW Sunday at 7-13 kt. Still expect sea breezes along parts of the immediate coast by late morning Sunday. Steady S winds Sunday night.

KBOS Terminal... High confidence in TAF.

KBDL Terminal... High confidence in TAF.

Outlook /Monday through Thursday/...

Monday: VFR. Windy with areas of gusts up to 30 kt. Slight chance SHRA.

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

Tuesday through Wednesday: VFR. Slight chance SHRA.

Wednesday Night: VFR. Chance SHRA, slight chance TSRA.

Thursday: VFR. Slight chance SHRA.

MARINE

Forecaster Confidence Levels...

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

Through Sunday Night...High confidence.

High pressure moves across the waters Sunday, then farther offshore Sunday night. Gusty NW winds diminish this evening, then become light and variable late tonight. More of steady S wind develops Sunday, with local seabreezes along the east coast of MA from mid-morning into the afternoon. Small Craft Advisories will gradually expire as rough seas subside late this afternoon into Sunday morning.

Outlook /Monday through Thursday/...

Monday: Strong winds with gusts up to 30 kt. Areas of rough seas. Slight chance of rain showers.

Monday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Chance of rain showers.

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

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

Wednesday: Winds less than 25 kt.

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

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

CLIMATE

Since we are potentially looking at our first 80-degree temperatures of the season early next week, here are some stats regarding average, earliest, and latest 80-degree temperatures.

Note that Hartford (Bradley) already hit 80 degrees this year back on March 31.

Boston: Average May 4, Earliest March 21, 1921, Latest June 16, 1924

Providence: Average May 4, Earliest March 20, 1945, Latest June 18, 1924

Hartford: Average April 28, Earliest March 9, 2016, Latest June 15, 1924

Worcester: Average May 4, Earliest March 15, 1990, Latest June 10, 1997

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 4 PM EDT this afternoon for ANZ230- 231-251. Small Craft Advisory until 8 AM EDT Sunday for ANZ250. Small Craft Advisory until 10 AM EDT Sunday for ANZ254. Small Craft Advisory until 8 PM EDT this evening for ANZ255- 256.