Area Forecast Discussion
Issued by NWS Boston, MA

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711 FXUS61 KBOX 221107 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 707 AM EDT Sat Mar 22 2025 .SYNOPSIS... Dry and mild today with some scattered showers possible late this afternoon. A cold front moves through tonight bringing windy and cooler conditions through Sunday morning. Another round of precipitation is expected early Monday into early Tuesday with mainly rain, but perhaps a period of wet light snow across parts of the interior early Monday morning. There is potential for another round of showers mid-week as a system tracks to the southeast of New England. && .NEAR TERM /THROUGH TONIGHT/... Key Messages... * Mainly dry and milder with highs in the 50s. * A few showers are possible this evening across the interior. After diminishing overnight, winds will back to the SW today becoming increasingly gusty after sunrise as mixing taps into 35-45 kt LLJ at 850 mb. This will result in gusty winds much of the day, as high as 20-30 mph for most locations. This comes ahead of a trailing cold front and mid level shortwave that passes late today into the overnight hours, increasing cloudcover and causing a few scattered rain showers across the interior late in the day. This should be the extent of notable changes given the limited moisture available. On the whole most will stay dry. Overnight the winds shift to the NW behind the front with CAA helping to keep winds mixing down overnight, so expect the breezy winds to continue. Post frontal cold advection will lead low temps to be 5-10 degrees cooler, in the upper teens and 20s. && .SHORT TERM /SUNDAY/... Key Messages... * Breezy winds in the morning, diminishing in the afternoon. * Dry and sunny. A ridge of high pressure moves overhead on Sunday leading to sunny skies and diminishing winds as the pressure gradient slowly slackens. Given the cooler airmass overhead, despite the decreased cloudcover high temperatures will be cooler than Saturday, topping out in the 40s, just on the cool side of average for late March. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
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Key Messages: * System brings rain Monday, with a brief period of wet snow possible Monday morning across the interior (mainly higher elevations). * Potential for system to bring a round of showers Wednesday. * Trough positions over northeast Thurs/Fri with temperatures near to slightly below normal. Sunday Night - Monday Night: An upper level trough and associated low pressure push across the Great Lakes region and toward New England overnight Sunday through Monday. There is sufficient synoptic support for our next chance for precipitation with New England in the left exit region of the upper jet coupled with a plume of anomalous moisture. Precipitation chances gradually increase early Monday morning from west to east, continuing through late Monday night/early Tuesday. There is still uncertainty in the details relating to the track/timing and cold air availability ahead of the system. This will play into the potential for light wet snow at the onset of the system. Ensemble guidance continues to signal at potential for a trace to light snow accumulation across the interior, mainly MA. Ensembles show generally a 20-60% chance for seeing over an 1" north of the Mass Pike. The higher probabilities (50%+) are confined to the higher elevations such as the Berkshires and northern border of central MA. This period of snow will likely be short-lived as the vertical column warms into mid-morning Monday as the warm front progresses north. The remaining portions of the interior have low probability to see any accumulation, but could see some flakes. Can`t rule out a few flakes mixed in further east toward Boston depend on the timing of the system with the cold air. Elsewhere will be rain with all locations changing over to rain by late AM/early afternoon. Ensemble means range QPF in the 0.25-0.50" range. Rain chances decrease from west to east late afternoon to early Monday evening. Tuesday and Wednesday: Conditions trend drier Tuesday behind Monday`s system with highs in the 40s and low 50s. Ensemble guidance shows another shortwave trough moving across mid-week that could bring some precipitation to southern New England. Details still need to be ironed out especially with the track which will impact QPF and precipitation chances. Recent trends have shown the main low tracking southeast of southern New England which would bring a higher chance for precipitation for RI and SE MA and isolated-scattered showers elsewhere. An upper trough stays over the northeast through Friday with a weak shortwave in the flow bringing some scattered showers later Thursday. Temperatures stay around to just below normal in the upper 40s to low 50s. A ridge moves in Saturday likely bringing a warming trend in temperatures for the weekend, but potentially a more unsettled pattern with some showers.
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&& .AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
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Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 12Z update... High confidence.... VFR through Sunday for all Southern New England terminals. Winds becoming SW and gusty once again today ahead of a cold front. Areas MVFR with the passage of this cold front along with spot showers. NW winds remain elevated overnight into Sunday morning, diminishing in the afternoon. KBOS TAF...High Confidence in TAF. KBDL TAF...High confidence in TAF. Outlook /Sunday Night through Wednesday/... Sunday Night: VFR. Chance SN. Monday: Mainly MVFR, with areas IFR possible. Breezy. RA, SN likely. Monday Night: Mainly VFR, with local MVFR possible. Breezy. Chance RA. Tuesday: VFR. Breezy. Tuesday Night: VFR. Wednesday: VFR. Chance RA.
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&& .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Winds turn SW and become gusty ahead of a cold front that should cross the waters tonight. Small Craft Advisories posted for all waters into tonight, continuing through Sunday for outer waters. Seas 3-5 ft today increase to 5-7 ft overnight on the outer waters, diminishing through the day on Sunday. Outlook /Sunday Night through Wednesday/... Sunday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain. Monday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Rain. Monday Night: Winds less than 25 kt. Areas of rough seas. Chance of rain. Tuesday: Winds less than 25 kt. Local rough seas. Tuesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain. Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 2 AM to 2 PM EDT Sunday for ANZ231- 232. Small Craft Advisory until 8 PM EDT Sunday for ANZ250-254>256. && $$ SYNOPSIS...BW/Mensch NEAR TERM...BW SHORT TERM...BW LONG TERM...Mensch AVIATION...BW/Mensch MARINE...BW/Mensch