AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 230 AM EDT Fri Apr 3 2026 .WHAT HAS CHANGED... No significant changes. && .KEY MESSAGES... - Mild weather returns for today, but another backdoor front brings a return to colder air later Saturday. - Expecting another round of rain Sunday with the arrival of yet another cold front. - Could see a few rain showers Tuesday, but otherwise expecting cooler temperatures and dry weather for the first half of next week. && .DISCUSSION... KEY MESSAGE 1...Mild weather returns for today, but another backdoor front brings a return to colder air later Saturday. The northeast low level flow that has brought the chilly air into the region from the Gulf of Maine will be transitioning to southwest flow as low pressure moves far north of the region but pulls a warm front up across the region. Associated with the low pressure is a decently strong low level jet (up around 2000-4000 ft above ground) with 40-50kt of wind. Luckily there is a stout inversion just below that level, so it will preclude most of those strong winds being able to mix to the surface (however gusts of 20-25mph are still expected. Those winds aloft will also advect in drier air aloft, and that will start to erode the inversion from the top. This in turn will allow skies to turn partly sunny across much of the interior by the afternoon. Temperatures should quickly rise well into the 60s in those areas. It will be a different weather regime along south coastal areas the Cape and Islands as those same milder southwest winds will result in low stratus and some fog to form as it flows over the still very cold waters. This will keep temperatures in these areas to the low 50s, at best. Typical spring time weather. Southwest flow weakens on Saturday as high pressure to the north starts to ridge southward. This is again a typical spring pattern that gives us those backdoor cold fronts. So as the winds turn to the north and northeast again, the cold air over the ocean spreads westward. Thus eastern coastal areas probably reach their high temperatures about noon and then fall quickly after that. It will take until early evening for that colder air to get into the CT River Valley. So by mid afternoon Saturday there should be a 25F difference between Hartford (mid 60s) and Boston (mid 40s). Stuck with the model blend for the temperature forecast which seems reasonable, but if the cold air comes in later that means the eastern half of the area will be warmer than the current forecast. So the error bars on this aspect of the forecast are higher than normal. KEY MESSAGE 2...Expecting another round of rain Sunday with the arrival of yet another cold front. Heading into Sunday morning, a low pressure system pushes south of the James Bay and into northern Quebec, with both warm and cold fronts extending southward into New England. We`ll see a short-lived surge of warm, moist air in southwesterly flow with the warm front, bringing afternoon high temperatures into the upper 50s/low 60s. Model guidance is hinting at a narrow band of moisture advecting into southern New England with the passage of the warm front (PWATs roughly around 1.0") which could bring some scattered rain showers early Sunday morning ahead of the main event. Expecting more widespread showers as the cold front moves through later Sunday, and combined with a 45-60kt LLJ and 1.25-1.5" PWATs, some brief downpours and rumbles of thunder could develop. KEY MESSAGE 3...Could see a few rain/snow showers Tuesday, but otherwise expecting cooler temperatures and dry weather for a good portion of next week. Both ensemble and deterministic model guidance are in good agreement that an upper-level trough pushes across the Great Lakes and into New England next week, leading to mostly dry weather but cooler temperatures. Ensemble guidance is indicating 850mb temperatures could get to below negative 7C Tuesday as a shortwave moves through, which would support some snow showers mixing in with rain. High temps for the first half of the week looks to be in the mid 40s to the lower 50s, but turn milder on Thursday with southwest flow developing ahead of our next cold front. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 06z update. Overall moderate confidence. General expectations in the forecast have not changed much. Currently visibilities are lowering as expected, with IFR conditions expected to be widespread by 12z. Have seen a few spotty showers and could have a few more through 10z or so, especially the northern areas. Have maintained some PROB30 mention, as chances are on the low side. Likely to also have -DZ in a few spots as well through 12 to 14z or so. Winds are starting to turn from E to SE, and that trend will continue and should be SW by 16z. Around this time, SW winds 2000-3000ft AGL should have increased to 40-50kt just above a strong inversion at that level. So have added in mention of wind shear from that time, through pretty much after 00z. The inversion slowly weakens as the afternoon progresses. As this happens, we will see surface winds start to gust 20kt or so, ceilings slowly lifting to VFR across the interior and visibilities also becoming VFR inland. However across the south coast, Cape and Islands, the warmer SW winds blowing across the cold waters will keep IFR ceilings locked in, with MVFR visibilities as well. PVD will be on the fringe. Friday night we could see those lower ceilings advance further north across all of southeast New England. The LLWS will slowly diminish as the low level jet moves offshore. KBOS Terminal...moderate confidence. Trends should be good, but the specific timing of onset of IFR ceilings and MVFR visibilities have an error bar of a couple of hours. Similarly with the timing of improvement in conditions mid-day. KBDL Terminal...moderate confidence, primarily due to uncertainty in timing of the transitions to MVFR/IFR tonight and then back to VFR mid-day Friday. Outlook /Saturday Night through Tuesday/... Saturday Night: Mainly MVFR, with areas IFR possible. Breezy. Chance SHRA, patchy BR. Sunday: Mainly MVFR, with areas IFR possible. Windy with gusts up to 35 kt. SHRA, isolated TSRA. Sunday Night: VFR. Breezy. Slight chance SHRA. Monday: VFR. Breezy. Monday Night: VFR. Tuesday: VFR. Slight chance SHRA, slight chance SHSN. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 1AM Friday update. Overall high confidence. Winds will be turning from easterly early this morning to southwest by mid-day, and then start to increase as low pressure far to the west approaches. All the available guidance suggests winds will start gusting around 25kt across much of the waters by this afternoon. Thus another round of Small Craft Advisories will be necessary. These winds will also produce some rough seas. Locally dense fog is also expected to develop across the waters, especially closer to the Cape and across the Islands and south coastal areas. This fog should last into early Saturday morning. Winds are expected to diminish Friday night and early Saturday as high pressure ridges into the area. Another low pressure system may produce winds near gale force on Sunday. Outlook /Saturday Night through Tuesday/... Saturday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft. Slight chance of rain showers, patchy fog. Sunday: Low risk for gale force winds with gusts up to 35 kt. Rough seas up to 11 ft. Rain showers. Sunday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Chance of rain showers. Monday: Winds less than 25 kt. Local rough seas. Monday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Tuesday: Winds less than 25 kt. Slight chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 4 PM this afternoon to 5 AM EDT Saturday for ANZ231>235-237. Small Craft Advisory until 6 AM EDT early this morning for ANZ250. Small Craft Advisory from 2 PM this afternoon to 7 AM EDT Saturday for ANZ250-254>256. && $$