Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 010620 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 120 AM EST Thu Dec 1 2016 .SYNOPSIS... Rain over southern New England during the predawn hours will exit the region at or before sunrise...followed by dry...breezy and mild conditions for the daylight hours of today. Dry conditions continue into much of the weekend, with a trend toward cooler temperatures. For early next week, an uncertain forecast but cool weather is expected with some potential for wintry precipitation sometime Sunday night into Tuesday. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 120 am Update... Rain shield over the region moving more rapidly than earlier thought with back edge of the rain at 1 am approaching the NY/western New England border! Thus rain will end about 07z/2am western MA/CT to about 09z/4am eastern MA. Heaviest rain will fall across northwest and northern MA. So other than standing water from overnight rains...the trend will be for dry weather during the morning commute. As triple point low tracks across the region it/s warm sector will briefly overspread the south coast with temperatures rising toward 60 degs! && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/... Thursday... A much better day is in store as intensifying low pressure lifts into the Canadian Maritimes. Skies will become partly sunny during the morning, but a scattered to broken deck of strato-cumulus clouds will likely move into the region from the west during the afternoon. This should yield partly to mostly cloudy skies with the clouds most abundant across the interior. Despite cold advection aloft, given the mild start it will take sometime for that to be reflected at the surface. Temps most of the day should be well up into the 50s. It will be a bit breezy though with Bufkit soundings supporting westerly wind gusts of 20 to 35 mph. Nonetheless, not a bad day for the first day of December. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... * Dry with cooling temperatures through the weekend * Low confidence in wintry precip Sun. night into Mon. There is continued uncertainty with regards to precipitation in the mid range models. The Canadian, GFS, and GEFS members all keep southern New England dry throughout the long term period. The EPS members have two low pressures approaching southern New England sometime Sunday night into Monday, one from the north and the other from the south. However, the members are well spread out as far as path and timing. The operational ECMWF indicates a similar solution but slower, delayed until Tuesday into Wednesday. Reading previous forecast discussions, this time period has been very uncertain with models flip flopping, so will keep with a blend of the models for the forecast. Friday through Sunday...High confidence. The upper level low and its surface reflections will move into the Maritimes, leaving southern New England in a tight pressure gradient between the departing low and a strong high pressure across the southeastern CONUS. This will result in rather blustery weather, in addition to temperatures returning to near normal or just below normal. Friday will be the warmest day with temperatures diminishing through the weekend. Sunday night through Wednesday...Low confidence. As stated above, there is quite a bit of spread in the models and the ensembles, leaving a lot of uncertainty for this period of the forecast. Option one - a continuation of the weekend - seasonable temperatures and dry. Option two - a period of wintry precipitation Sunday night and Monday. Option three - a period of wintry precipitation, but not until Tuesday and Wednesday. Which one it will be remains to be seen. Will need to keep an eye on the models over the next few days. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 120 am update... Short Term /through Friday/... Thru 12z...high confidence in trends but lower in exact timing. IFR and MVFR in periods of heavy rain will begin to improve from 07z west to 09z east as back edge of rain sweeps across the area. Additional improvement from 09z to 12z with conditions lifting to VFR west to IFR-MVFR RI and eastern MA. Also expect a wind shift to the SW between 09z to 12z. After 12z...high confidence but slightly lower on exact timing this morning. West winds increase to 25 to 35 kt around or shortly after sunrise. Then wind gusts not quite as strong in the afternoon...closer to 25 kt. Any leftover showers in MVFR-IFR over RI and eastern MA at 12z quickly improves to VFR. Across CT and western-central MA...should be VFR at 12z however marginal MVFR- VFR cigs quickly move back into the area and will overspread RI and eastern MA during the afternoon. Tonight...high confidence. VFR but areas of MVFR cigs across the higher terrain. West winds 5 to 10 kt except 15 to 25 mph along the coast and especially Cape Cod and the Islands. Friday...moderate confidence with some uncertainty on extent of lake effect snow/rain showers entering MA/RI/CT. Marginal VFR-MVFR cigs as lake effect rain/snow showers spilling over the Berkshires into northern MA and eventually CT/RI and southeast MA later in the day. West winds somewhat gusty up to 25 kt. KBOS TAF...rain shield moving rapidly eastward with dry weather and IFR cigs improving to MVFR by 09z-11z. Moderate confidence. KBDL TAF...rain shield moving rapidly eastward with dry weather and IFR cigs improving to MVFR by 08z-10z. Moderate confidence. Outlook /Friday Night through Monday/... Friday night through Sunday...High confidence. Mainly VFR. Blustery W-NW winds expected. Sunday night and Monday...Low confidence. As stated in the long term section there is much uncertainty. Could be VFR and dry or a mix of MVFR/IFR and wintry precip especially across the interior. && .MARINE... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Friday/... Tonight...Moderate to high confidence. Approaching low pressure will allow easterly winds to increase tonight with speeds of 25 to 35 knots. There may be a brief lull in the wind gusts, but they will then shift to the south toward daybreak as most of our waters warm sector resulting in another round of 25 to 35 knot gusts. Small craft headlines are posted all open waters, except for Gales on the eastern outer-waters for a period of 35 knot wind gusts. Thursday...High confidence. Westerly wind gusts of 25 to 35 knots expected in the cold air advection pattern as intensifying low pressure lifts towards the Canadian Maritimes. Small craft headlines all waters, except will continue Gales for our eastern most outer-waters through the morning. Seas on the order of 6 to 10 feet expected across our outer-waters. Outlook /Friday Night through Monday/... Moderate confidence. Small craft conditions to start. Then winds and seas gradually diminish throughout the period, falling below small craft criteria for a period Sunday. Then there is a possibility that a low pressure system approaches the waters with a resulting increase in seas and wind. There is also a possibility that high pressure builds into the region and winds and seas remain below small craft criteria. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ231>235-237-251-256. Small Craft Advisory from 8 AM this morning to 5 PM EST this afternoon for ANZ230-236. Gale Warning until noon EST today for ANZ250-254-255. && $$ SYNOPSIS...Frank/RLG NEAR TERM...Frank/Nocera/RLG SHORT TERM...Frank LONG TERM...RLG AVIATION...Frank/Nocera/RLG MARINE...Frank/RLG is the U.S. government's official web portal to all federal, state and local government web resources and services.