AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 639 PM EST Wed Jan 29 2025 .SYNOPSIS... Cold conditions and blustery winds last into Thursday. We continue to monitor a storm system that moves across the region Friday into early Saturday morning. Uncertainty remains in the precipitation type with potential for wintry mixed precipitation or light snow Friday night, especially for areas of northern MA. After a quick clipper system Sunday night into Monday, conditions trend drier early next week with temperatures in the 30s. && .NEAR TERM /THROUGH THURSDAY/... A snow squall that made its way through western and central MA has switched to rain as it has made its way east into a warmer area. Rain is expected to affect SE MA and RI until around 5 pm tonight. Following this snow and rain, a strong cold front will be moving across southern New England. 850 mb temps may reach as low as -20C by early Thursday morning, and may settle around -15C during the day. Lows tonight expected to be in the teens and single digits. The cold airmass remains over the region, and the tighter pressure gradient between the high pressure building in from the SW and the low pressure moving offshore to the northeast will maintain gusty winds for much of the day Thursday. Wind chills will likely be in the teens with highs in the 20s and dry conditions during the day. Once this gradient slackens a bit, winds will die down going into the evening hours. Wind Advisories remain in effect through 7 am Thursday (the Cape and Islands) and 10 pm (rest of MA, RI, and northern CT) due to the gusts from the passing cold front and the strong CAA coming with it. Gusts up to and over 50 mph continue to be possible for this reason. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/... High pressure moves offshore, taking the core of the colder air with it. While still below normal, light S to SW winds should be sufficient to boost low temperatures Friday morning by 5-10 degrees from Thursday morning. A low pressure is expected to push a warm front into southern New England along with the risk for some light precipitation Friday. Timing will be everything. Should the precipitation arrive early enough in the day, there is a risk for some freezing rain. Eventually, warmer air should end that threat by mid to late morning. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Key Messages: * Turning drier with cooler than normal temps for this weekend. * Possible Clipper system may bring light snow late Sun night/Mon. Details: Friday night, a system continues to moves across southern New England bringing steady precipitation. There is still some uncertainty on precipitation type with differences among deterministic and ensemble guidance. This will mainly depend on how far north the warm front tracks. If it ends up tracking a little more south, this could favor a variety of different precipitation types as opposed to just rain (rain/snow, snow, sleet, freezing rain). More recent model runs have shown advection of colder air from the north (850mb temps below freezing) after 00z. In these particular runs, there are light snow accumulations north of the Mass Pike. Where is becomes uncertain is how cold this air is and how far south it goes. These things will factor into precip type and location. We`ll have to see how the next few models runs trend, but overall there is potential for mixing in or changing over to frozen precipitation, especially for areas in northern MA. Precipitation gradually diminishes from west to east before sunrise. During the day Saturday high pressure shifts in with dry conditions. NW flow and cold advection will support a cooler and breezy day with highs in the upper 20s and 30s. Similar conditions prevail during the day Sunday. There is a general model consensus that a quick moving clipper system moves across the region in the Sunday night to Monday AM timeframe. There is uncertainty in the track and overall strength of the system which has lead to variance in the amounts. This will likely start as snow with potential for rain to mix at toward Monday morning. Details will become more clear as we gain more confidence in the track. There may be a brief period Monday morning-early afternoon that temperatures rebound into the upper 30s and 40s before a cold front brings another surge of cold air in from the north. This will result in cooler temperatures for Tuesday and Wednesday in the 30s. && .AVIATION /23Z WEDNESDAY THROUGH MONDAY/... Forecast Confidence Levels: Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 00Z TAF Discussion: Tonight: High confidence. VFR. Gusty westerly winds continue tonight with gusts 20-30 kts Thursday: High confidence. VFR. Gusts may drop closer to 20-25 kts for a period early Thursday morning. Mid-morning to late afternoon, gusts may pick up again to 25-30 kts. Gusts gradually trend downward late afternoon (20-00z). Gusts diminishing for most by 00z. Thursday Night and Friday: Medium Confidence. Light SW winds. Precipitation develops mid-morning to early afternoon. Should likely be rain. If precipitation develops earlier in the morning, there is potential for areas of freezing rain at onset. MVFR/IFR cigs developing in the afternoon to early evening. KBOS TAF...Moderate confidence in TAF. KBDL TAF...High Confidence in TAF. Outlook /Friday Night through Monday/... Friday Night: MVFR/IFR conditions possible. Breezy. RA likely, chance SN, FZRA likely. Saturday through Saturday Night: VFR. Breezy. Sunday: VFR. Slight chance SN. Sunday Night: MVFR/IFR conditions possible. Breezy. Chance SN, chance RA. Monday: Mainly VFR, with local IFR possible. Breezy. Chance RA. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High- greater than 60 percent. High Confidence. Gale force winds possible for all coastal zones through tonight as a strong cold front approaches the waters. Dangerous waves up to 10 feet in the open waters are also likely. Light to moderate freezing spray will be a concern tonight into Thursday due to the much colder air behind the front. For this reason, a Freezing Spray Advisory is in effect starting at 7 pm tonight through Thursday evening. Winds are expected to decrease going into Thursday, but they are still expected to be from the W to WNW at 20 to 30 knots to start tomorrow. Winds will continue to diminish going into Thursday night into Friday and shift more to the south. Outlook /Friday Night through Monday/... Friday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Rain. Local visibility 1 to 3 nm. Saturday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Rough seas up to 10 ft. Saturday Night: Winds less than 25 kt. Areas of rough seas. Sunday: Winds less than 25 kt. Seas locally approaching 5 ft. Sunday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of rain, chance of snow. Monday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Chance of rain. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Wind Advisory until 10 PM EST this evening for CTZ002>004. MA...Wind Advisory until 10 PM EST this evening for MAZ002>021-026. Wind Advisory until 1 AM EST Thursday for MAZ022>024. RI...Wind Advisory until 10 PM EST this evening for RIZ001>007. Wind Advisory until 1 AM EST Thursday for RIZ008. MARINE...Gale Warning until 7 AM EST Thursday for ANZ230>237-250-251- 254>256. Freezing Spray Advisory until 7 PM EST Thursday for ANZ230>232- 250-251-254-255. && $$