AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 221 PM EDT Sun Apr 5 2026 .WHAT HAS CHANGED... No significant changes. && .KEY MESSAGES... - A few showers early this morning, then more widespread showers move through SNE this afternoon into early evening associated with a cold front. - Clearing and colder overnight, then blustery Monday. - Could see a few rain/snow showers Monday night into Tuesdaymorning, but otherwise expecting cooler temperatures and dry weather for a good portion of next week. - Second half of next week looks mainly dry with temperatures on the rise. && .DISCUSSION... KEY MESSAGE 1...A few showers this morning, then more widespread showers move through SNE this afternoon into early evening associated with a cold front. The backdoor front which moved through SNE Saturday will return northward as a warm front later this morning. Modest low level jet combined with marginal elevated instability will bring a few showers this morning and possibly a rumble of thunder. Lots of stratus and fog also expected this morning with abundant low level moisture trapped within a strong surface inversion. The fog should lift later this morning and afternoon as SW flow develops but stratus may linger as low level moisture is persistent. The surface inversion eventually erodes in the afternoon but mixed layer is quite shallow. This combined with cloud cover and showers will limit how mild it gets, expecting highs reaching upper 50s and lower 60s, but cooler along the south coast. It will also be breezy over the Cape/Islands with low level jet across the region, expecting gusts to 35 mph at times. We expect a period of widespread rain moving west to east across SNE during the afternoon as a cold front moves through. The cold front will be accompanied by a deep moisture plume with PWATs 1-1.5" and right entrance region of upper jet so a period of widespread showers is likely. Marginal elevated instability is also present so can`t rule out an isolated t-storm. The bulk of the showers should end by late afternoon, but will linger into the evening across SE MA and Cape/Islands with later timing of cold front. KEY MESSAGE 2...Clearing and colder overnight, then blustery Monday. Cold front moves across the Cape/Islands in the evening then offshore overnight. The frontal passage will be followed by clearing and colder conditions and it will become blustery overnight in the cold advection pattern. Lows will drop into the 30s. Blustery but dry weather continues Monday with soundings showing a deepening and well mixed boundary layer supporting gusts to 35 mph at times. Diurnal cu will develop as upper trough and cooling temps aloft move through. Highs will range from the upper 40s to lower 50s which is near or slightly below normal for early April. KEY MESSAGE 3...Could see a few rain/snow showers Monday night into Tuesday morning, but otherwise expecting cooler temperatures and dry weather for a good portion of next week. Expecting an upper-level trough to push across the Great Lakes and into New England early next week, leading to mostly dry weather and cooler temperatures. Ensemble guidance is indicating 850mb temperatures could get to below -5C and 500mb temperatures below - 30C Tuesday as a shortwave moves through, which would support some light snow showers developing and mixing in with rain showers, especially over the higher elevation areas, though we`re not expecting any road or travel impacts. Surface temperatures will likely hover near or possibly just below freezing Monday night into Tuesday morning, but they`re expected to make a fast recovery later Tuesday morning... into the mid 40s. Otherwise, dry weather with high temps mainly in the middle 40s to the lower 50s and overnight temperatures ranging from the mid 20s to mid 30s through Wednesday night. KEY MESSAGE 4...Second half of next week looks mainly dry with temperatures on the rise. A large high pressure system moves into the Mid-Atlantic region by the second half of next week, bringing predominantly southwesterly flow and dry conditions back to southern New England. The warmer airmass advecting into the region will allow temperatures to recover back into the 50s and 60s by the end of the week. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 18z TAF Update: Today: Moderate confidence. Still IFR/LIFR due to stratus, mist and areas of fog until cold frontal passage. Cold front has moved into Southern New England and is bringing widespread rains, with some brief downpours possible. Expect rains to come to an end from 21-23z west to east, though could linger until 02z for the Cape and Islands. Post-frontal, expect lifting of ceilings into the SCT- BKN VFR range and winds becoming NW and increasing to around 10 kt. Tonight: High confidence. Leftover MVFR ceilings should scatter out to VFR all areas early. NW winds increase to 10-15 kt with developing gusts to 25 kt after midnight. Monday: High confidence. Mainly VFR; for the interior higher terrain, wouldn`t rule out some MVFR bases interior high terrain in the aftn as disturbance aloft approaches and there could be some hit-or-mostly-miss sprinkles or flurries. Main concern for aviation is gusty NW winds, around 12-17 kt with gusts 25-35 kt, highest at ORH. Monday Night: High confidence overall, though moderate on possible precip chances. Disturbance aloft moves through Southern New England Mon night, which will bring at least SCT-OVC mainly VFR ceilings. Less clear if we can wring out any precip; if we do, potential for brief periods of MVFR visby -SHSN. NW winds decrease to 8-12 kt with gusts in low 20s kt range. KBOS Terminal...Moderate confidence. IFR, widespread rain at MVFR visbys continue thru 23z with arrival of cold front. Clearing to VFR likely into the early evening with NW winds increasing to around 10-13 kt before midnight, with gusts to 25 kt toward daybreak Mon. KBDL Terminal...Moderate confidence. IFR/LIFR, widespread rain at MVFR visbys continue thru 22z with arrival of cold front. Clearing to VFR likely by sundown, with NW winds increasing to around 10-15 kt late evening, with gusts to 25 kt toward daybreak Mon. Outlook /Monday Night through Friday/... Monday Night: VFR. Chance SHRA, chance SHSN. Tuesday: Breezy. Chance SHRA, chance SHSN. Tuesday Night: Breezy. Wednesday through Wednesday Night: Thursday: Breezy. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. High confidence. Gusty pre-frontal SW winds today with gusts to 25-35 kt as LLJ will be over the waters. Will continue SCA although a few near gale force gusts possible. The LLJ moves offshore tonight but expect post- frontal W gusts to 25 kt late tonight and Monday. Areas of fog this morning with poor vsbys, then showers mid afternoon into this evening. An isolated t-storm is possible. Outlook /Monday Night through Friday/... Monday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers. Tuesday: Winds less than 25 kt. Chance of rain showers. Tuesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Wednesday: Winds less than 25 kt. Areas of seas approaching 5 ft. Wednesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Thursday: Winds less than 25 kt. Seas up to 5 ft. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ230>234-236-251. Small Craft Advisory until 2 AM EDT Monday for ANZ235-237. Small Craft Advisory until 2 PM EDT Monday for ANZ250. Small Craft Advisory until 8 PM EDT Monday for ANZ254>256. && $$ $$