124 FXUS61 KBOX 291311 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 911 AM EDT Fri Apr 29 2022 .SYNOPSIS... Mostly sunny, dry and blustery weather continues through Saturday. Mild, dry and quiet weather on Sunday with high pressure in control. Pattern change coming next week with shower chances on Monday and very late Tuesday into Wednesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 910 AM Update... * Dry & Breezy today with highs mainly in the mid-upper 50s Previous forecast is on track. Plenty of sunshine at mid-morning as upper level closed low continues to spin to our northeast. This will continue to result in breezy conditions with northwest wind gusts of 20 to 30 mph into the afternoon. This upper level low does slide further south this afternoon, which will allow for some clouds to increase across eastern MA and RI but it will remain dry. High temps will reach the middle to upper 50s in many locations this afternoon, but we can not rule out a few spots in the lower CT River Valley touching 60. It will feel a bit chillier though given the breezy conditions. Please see our Fire Weather Discussion for more information on the elevated fire weather concerns today. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... 355 AM Update: Tonight: NW winds turn less gusty tonight, with speeds also easing a bit as well. Expecting clearing skies for many, though the lone exception is later in the overnight as cloudiness associated with our pesky upper low and a vort max rotating around it over our far eastern waters brushes the Cape and Islands. Could even be a spotty shower underneath this deck but should be dry much of the time. Question for tonight is temperatures supporting a possible frost where the frost/freeze program is active, especially in SE MA, northern Providence County in RI and Windham County in CT. There's a couple of uncertainties: one being on winds easing enough (and that's the biggest one); the other is that it has been so dry that it could preclude a frost too. Lows range in the lower to mid 30s, with upper 30s in the urban areas. Saturday: Continued mostly sunny and dry weather returns for Saturday, with more modest northerly breezes. Should be able to mix to around 850 mb and with temps at that level recovering to around +0C, 60-degree highs seem feasible. The exception is across eastern MA and portions of RI; it is a more challenging temperature forecast here as pressure gradient eases to the point where the potential exists for an afternoon sea breeze. This could bring scattered cloudiness and cooling temps at least to the immediate coastlines; for these areas have highs closer to the mid 50s. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Highlights * Dry and quiet weather persists Saturday night through much of Sunday. Temperatures trending near to above normal. * Still looking mild for a good portion of next week, but may fall a bit cooler than normal on Monday due to onshore flow. * Could have some showers very late Sunday into Monday and late Tuesday into Wednesday. Drier weather returns Thursday. Saturday night through Sunday... An amplified ridge will start off over the OH Valley into James Bay Saturday night. This will build into the eastern Great Lakes and Quebec on Sunday. The ridge builds over New England and eastern Quebec late on Sunday, while a trough digs into the Great Lakes region. High pressure builds over the region Saturday night into early Sunday. The high moves offshore/over northern New England late on Sunday into early Monday. Dry and quiet weather through this period with high pressure in control. Expect there to be relatively clear skies and light winds Saturday night into Sunday. Given the high being overhead did nudge down low temps to the 25th percentile of guidance, but may need to be lowered further in future updates. If we completely decouple and winds are a bit lighter, then it is not out of the question there could be some patchy frost across portions of SE MA. Have held off from adding at this point. Low temps will generally be in the 30s, but there will be some low 40 degree readings along the immediate coastline along with the Cape/Islands. Temperatures moderate to above normal readings for this time of year. Will see the low/mid level ridge axis slide over southern New England, which shifts flow aloft to a W/SW direction by the afternoon. This results in 925 hPa temps of roughly 8-12 degrees Celsius. The result will be fairly widespread highs in the 60s and perhaps even some 70 degree readings in the CT River Valley. Monday through Wednesday... Still a moderate amount of uncertainty during this period, especially late on Tuesday through Wednesday. Main issues are the position of the ridge axis for Monday. Tuesdays weather will largely be dependent on another ridge building in along with the timing/amplitude of a trough lifting into the Great Lakes Region. Wednesday will largely be impacted by amplitude and position of that trough lifting over across the Great Lakes region. At the surface will have a frontal system slide through late on Sunday through Monday. That frontal system/boundary may still be stationary over the region for Tuesday, but high pressure will nudge in from the Gulf of Main/Nova Scotia. As for Wednesday will have a low lift across the Great Lakes potentially into Quebec. Details for very late Sunday into Monday Does appear with the frontal system lifting through there will be the opportunity for light showers during this period. Did dial back precip chances a little bit as the NBM appears to be a bit too fast still, as it has been the past couple of days. The key to have far into the region the precip will spread is based on where the ridge axis sets up per WPC Cluster Analysis. A ridge axis that is situated just to the west of our region would result in less precip over our area, likely more confined to the interior versus much of the region. At this point there are 45 members out of 100 that fall into this camp, which the vast majority are EPS members. A good proxy for this solution is the latest ECMWF guidance. The wetter solutions feature the ridge axis being over New England, which accounts for 55 members at this point. Regardless does appear there will be some light precip. Have kept PoPs in the slight chance to chance category at this time. The other issue on Monday will be a weak low develops south of the south coast. Depending on how deep it is will impact if we see more of an onshore flow versus weak southerly. Have stuck with the NBM at this time, but temps will need to be lowered if the onshore flow solution appears more favorable. Highs range from the mid 50s to low 60s. Tuesday and Wednesday details Not sold that Tuesday will be completely dry with the frontal boundary nearby/over the region. Deterministic guidance suggests the high nudging in from the Gulf of Maine/Nova Scotia should suppress this activity, but details are more hazy when looking at ensemble guidance. Have leaned on the NBM for this period, but could see temps needing to also be reduced if onshore flow persists. Highs range from the mid 50s to 60s. Better shot for precipitation during this period comes very late Tuesday, but mostly on Wednesday. A trough lifts across the Great Lakes potentially into Quebec, but there is uncertainty on the amplitude and position of the trough. Should see a surface low lift into the eastern Great Lakes or into Quebec. This will keep us within the warm sector and bring showers. Some uncertainty in how much QPF we realize as the system move through. This could also linger into early Thursday. Given the uncertainty have leaned on the NBM for now. Will have widespread highs in the 60s with some low 70 degree readings in the CT/Merrimack Valleys. Thursday... Still uncertain this far out with a ridge over the Mississippi River Valley and a cutoff over NE Canada. WPC Cluster Analysis shows pretty widely varying solutions, most lean toward a wetter solution. There are 69 members with a wetter solution versus 31 with a drier solution in mind. The key will be the position of the cutoff along with the amplitude/position of the ridge. Deterministic guidance showers a drier solution with high pressure overhead, but this is similar at this point to the 31 members within cluster 1. Have just stuck with NBM for now which features slight chance to chances of PoPs. && .AVIATION /13Z FRIDAY THROUGH TUESDAY/... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Today...High confidence. VFR across southern New England today. However, will see some 5-8 kft cloud bases across the region from roughly 17-23Z. These clouds will scatter out late. Will have NW winds throughout the day. Expect speeds in the 10-20 kt range, with 15-20 kts during the morning. Should see 25-30 kt gusts this morning lessen to 20-25 kts during the afternoon. Tonight...High confidence. VFR, but may see some clouds moving in late tonight as a shortwave digs in from the north. These bases will be around 5-10 kft. Could perhaps see an isolated rain shower over the Cape/Islands. Will have NW winds around 5-10 kts. Gusts should cease around 00-03Z. Saturday...High confidence in categories, moderate on sea- breeze potential. Any VFR/low-prob MVFR decks FMH-HYA-ACK clear by mid-morning. While N/NW winds continue around 7-10 kt interior TAFs, weakening pressure gradient could allow for sea-breeze to develop for BOS/PVD. Timing still unclear but current thinking after 18z. KBOS TAF...High confidence in TAF. KBDL TAF...High confidence in TAF. Outlook /Saturday Night through Tuesday/... Saturday Night through Sunday Night: VFR. Monday: Mainly VFR, with local MVFR possible. Chance SHRA. Monday Night: Mainly VFR, with areas MVFR possible. Chance SHRA. Tuesday: Mainly VFR, with local MVFR possible. Slight chance SHRA. && .MARINE... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Today: High confidence. SCAs remain in effect on all waters through the afternoon, but will diminish some by early evening. This will allow us to drop many of the SCA headlines early this evening, but will need to continue them through early Saturday morning on the eastern outer waters. NW winds will resume around 25 to 30 kt through the early afternoon, gusts then ease to around 15-25 kt strongest on the eastern outer waters. Seas 2-4 ft nearshore, 4-6 ft offshore decrease by about a foot thru today. Tonight: High confidence. NW gusts around 10-15 kt all southern waters and the eastern nearshore waters, and around 20-25 kt on the eastern outer waters. Seas around 2 ft nearshore, 3-5 ft offshore. Saturday: High confidence. NW gusts continue to decrease to around 10 kt by afternoon, with seas lowering to 2-4 ft on all waters. Outlook /Saturday Night through Tuesday/... Saturday Night through Sunday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Monday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers. Monday Night: Winds less than 25 kt. Seas up to 5 ft. Chance of rain showers. Tuesday: Winds less than 25 kt. Seas up to 5 ft. && .FIRE WEATHER... 350 AM Update: Special Weather Statements for elevated fire weather concerns are in effect for MA RI, and CT today. Dry weather and gusty winds along with low RH values are again expected. Dewpoints in the teens early this morning are expected to fall into the single digits by the afternoon, and could support lowest RH's in the lower to mid teens percent across western MA and CT. Min RH forecast for the rest of Southern New England to range from 20 to 30 percent. Northwest winds top out in the 25-30 mph range. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 4 PM EDT this afternoon for ANZ230>237-251. Small Craft Advisory until 8 AM EDT Saturday for ANZ250-254. Small Craft Advisory until 8 PM EDT this evening for ANZ255- 256. && $$ SYNOPSIS...BL/Loconto NEAR TERM...Frank SHORT TERM...Loconto LONG TERM...BL AVIATION...BL/Loconto MARINE...Frank/BL/Loconto FIRE WEATHER...Staff