064 FXUS61 KBOX 191141 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 641 AM EST Thu Nov 19 2020 .SYNOPSIS... High pressure over Southern New England shifts offshore today and lingers through the weekend. A warm front passes to the north. Dry conditions continue into the weekend, with a warming trend into the weekend. Unsettled weather is expected next week. The next chance of rain comes on Monday, with another chance of precipitation middle of next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 630 AM update... Clear and calm conditions this morning have allowed for better than expected radiational cooling to take many locations into the mid to upper teens. As such, forecast temperatures have been lowered quite a bit, especially in southeast MA and the other typically cold spots. Previous Discussion... High pressure moves offshore, bringing a southwest surface flow to Srn New England. Upper ridge flattens as it moves over the region. This turns the upper flow across the Nrn USA into a zonal pattern with shortwaves moving through the flow. Today... High pressure moves offshore with developing southwest surface flow in the afternoon. Warm advection will limit mixing to 950 mb or lower. Winds in this layer reach around 20 kt in the mid-late afternoon. Temperatures in this layer support max sfc temps in the 40s, possibly lower 50s along the south coast due to advection off the warmer waters. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Continued southwest surface flow will maintain wind gusts 20 to 25 kts, possibly 30 kts on the islands. Variable sky cover, but mainly mid to high clouds. The air mass will be sufficiently dry to support fair weather. Dew points will climb into the 30s and 40s tonight, maintaining min temps only about 10F lower than the daytime highs. Temperatures at 950 mb will be 8-10C by Friday, supporting max sfc temps in the upper 50s and lower 60s. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Highlights... * Temperatures oscillating above and below normal through the extended forecast, but no extreme temperature departures expected * Dry weather prevails most of the weekend * Rain chances increasing late Sunday and especially Monday before drying out for Tuesday. Another system arrives around mid week. Details... Quiet weather continues through the weekend under initially zonal flow, becoming more meridional by Sunday as a mid level trough approaches. Another day of slightly above normal temperatures is on tap for Saturday (reaching the mid to upper 50s). However, the passing sfc trough to our north and incoming high pressure turn winds out of the northwest then northeast, dropping temps back below normal by Sunday. Most interior locations won't make it out of the 40s. The good news is that with high pressure overhead things remain dry with light wind. Saturday will be clear to partly sunny then clouds increase on Sunday as moisture is pulled north ahead of our next frontal system. A period of unsettled weather then arrives late Sunday into Monday. This, as a warm front initially lifts north late Sunday, followed quickly by the cold front sometime during the day on Monday. Exact timing is uncertain at the moment but it does look as if much of the region may get into the warm sector on Monday with highs approaching 60 or more and dewpoints in the 50s. As is often the case southeast MA and RI stand the best chance of seeing highs surpass the 60 degree mark. Guidance indicates 850 mb temps anywhere from 4 to 10 C, so still some decent uncertainty as to how warm we get. Along with these temperatures swings comes widespread rain chances. There will be some upper level jet support for synoptic lift in addition to warm frontal isentropic lift and convergence ahead of the cold front. The system is rather progressive, and things should dry out by Tuesday. It is far too soon to be confident in how much rain a particular area may get but guidance suggests as much as 0.5 to 0.75" is possible. A colder and drier airmass moves in for Tuesday...the next system following not far behind sometime around mid week as a mid/upper low ejects out of the Ohio Valley. Stay tuned. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Today... VFR. Increasing southwest wind with gusts 20 to 25 kt late afternoon. Tonight...VFR. Continued southwest gusts 20 to 25 kt. Friday...VFR. Southwest wind with gusts 20 to 25 kt, strongest on the South Coast. BOS TAF...High confidence in TAF. BDL TAF...High confidence in TAF. Outlook /Friday Night through Monday/... Friday Night: VFR. Breezy. Saturday through Saturday Night: VFR. Sunday: Mainly VFR, with areas MVFR possible. Breezy. Slight chance SHRA. Sunday Night: Mainly VFR, with local IFR possible. Breezy. Chance SHRA. Monday: VFR. Breezy. Chance SHRA. && .MARINE... Today... High pressure moves offshore. Increasing southwest wind with late afternoon/evening gusts of 25 to 30 kt. Seas around 2 feet midday, but building to near 5 feet in the evening. Small Craft Advisory for all waters starting this evening and continuing through Friday. Tonight... Southwest wind gusts around 30 kt. Seas building to 5-9 feet on the exposed waters. Friday... Continued southwest winds gusting to 30 kt, but diminishing late in the day. Seas 5-9 feet diminishing late in the day. Outlook /Friday Night through Monday/... Friday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Saturday: Winds less than 25 kt. Seas locally approaching 5 ft. Saturday Night: Winds less than 25 kt. Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft. Sunday Night through Monday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 3 PM this afternoon to 7 PM EST Friday for ANZ231>235-237-250-251-254>256. Small Craft Advisory from 3 PM this afternoon to 3 PM EST Friday for ANZ230-236. && $$ SYNOPSIS...WTB/BW NEAR TERM...WTB/BW SHORT TERM...WTB LONG TERM...BW AVIATION...WTB/BW MARINE...WTB/BW