textproduct: Boston / Norton

WHAT HAS CHANGED

Forecast remains on track.

KEY MESSAGES

- While the risk for severe weather remains low, scattered diurnal showers and thunderstorms are possible today. Otherwise, not as gusty.

- Periods of heavy rain possible Monday into early Tuesday. Drier air with seasonable temperatures expected midweek. Chances for rain return for the end of next week.

DISCUSSION

KEY MESSAGE 1...While the risk for severe weather remains low, scattered diurnal showers and thunderstorms are possible today. Otherwise, not as gusty.

Not much change to the overall synoptic pattern today. We will still have a mid level trough over eastern Canada as well as another sheared shortwave this afternoon and evening. Projected CAPE values still between 500-1,000 J/kg. Almost no vertical shear to speak of, so not overly concerned about the prospects for severe weather. This should be enough for another round of scattered afternoon showers and thunderstorms. The greatest risk is towards northeast MA.

Tricky forecast with respect to coastal winds. Westerly winds do look to be just strong enough to prevent the seabreeze from moving too far inland. A seabreeze front could provide a greater focus for showers and thunderstorms. At this time, expecting only local seabreezes rather than the typical front which pushes inland to the I-95 corridor. This will need to be monitored through today.

KEY MESSAGE 2...Periods of heavy rain possible Monday into early Tuesday. Drier air with seasonable temperatures expected midweek. Chances for rain return for the end of next week.

A low pressure system is expected to bring a widespread, soaking rainfall to southern New England from Monday afternoon into Tuesday. The probability for 1+ inch of storm total rainfall was still between 70 to 80 percent across most of our region. The probability for 2+ inches of rainfall remained about 30 to 50 percent, greatest across western MA and CT. Groundwater and streamflow observations were less than the 10th percentile. This indicates we have plenty of room to accommodate this rainfall. Perhaps a different story in the urban areas. While there could be thunderstorms, we do not anticipate these to be strong enough to result in flooding. This will still need to be monitored. We should dry out from west to east as a low pressure along the south coast of New England moves offshore.

High pressure builds into the region behind this system, providing drier with and seasonable temperatures for the middle of the week. Chances for rain begin to increase once again by the end of the work week.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

Forecaster Confidence Levels...

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

Today: High confidence.

VFR. W/WNW 6-12 mph. A few brief gusts up to 18 kts possible late morning-early afternoon. It is possible if winds end up lighter, a sea breeze may develop late afteroon. There is a low risk for an isolated shower or storm after 2 PM through this evening.

Tonight: High Confidence.

VFR with light and variable winds.

Monday: High confidence.

VFR for most of the day. S/SSE 8-12 kts. MVFR ceilings arrive from west to east in the afternoon with the arrival of rain.

KBOS Terminal...Moderate confidence in TAF. Have some concern for a seabreeze if winds slacken later today. Most likely time for a seabreeze would be between 20-00Z. There is also a low risk (<20%) for an isolated shower or storm at or near the terminal late afternoon/early evening mainly after 20Z. KBDL Terminal...High confidence in TAF.

Outlook /Monday Night through Thursday/...

Monday Night: Mainly MVFR, with areas IFR possible. Breezy. SHRA, slight chance TSRA.

Tuesday: Mainly VFR, with local IFR possible. Breezy. Chance SHRA.

Tuesday Night through Thursday: VFR.

MARINE

Forecaster Confidence Levels...

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

Small Craft Advisories will be allowed to end early this morning. Risk for scattered showers and isolated thunderstorms this afternoon and evening, especially near the east coast. Any showers and thunderstorms should diminish after sunset.

Outlook /Monday Night through Thursday/...

Monday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Rain showers, slight chance of thunderstorms.

Tuesday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain showers, slight chance of thunderstorms.

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

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

Thursday: Winds less than 25 kt.

BOX WATCHES/WARNINGS/ADVISORIES

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