Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 221903 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 303 PM EDT MON AUG 22 2016 .SYNOPSIS...
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High pressure will bring beautiful late summer weather through Tuesday with low humidity. Warmer and more humid weather is expected Wednesday through Friday along with a low risk of showers and thunderstorms Thu night into Friday. Dry and less humid weather may return next weekend.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Secondary mid level shortwave swings through northern New England this evening then offshore tonight, with main effect being another pulse of gusty winds along the coast and adjacent E MA waters. Otherwise, high pres builds in from the west with clear skies and diminishing winds. With dry airmass in place, ideal radiational cooling will allow low temps to drop into the mid/upper 40s in the colder spots in the CT valley and interior E MA, with 50s elsewhere. The mildest spot will be the urban heat island in Boston and also Nantucket with lows around 60. Patchy late night radiation fog possible.
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&& .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
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Tuesday... High pres in control will bring sunny skies and lighter winds. Despite a chilly start to the day, moderating 850 mb temps to 11-12C will result in highs reaching the upper 70s to lower 80s, a bit cooler higher terrain. Weak seabreezes may develop in the afternoon. Low humidity levels with dewpoints in the upper 40s to lower 50s. Tuesday night... High pres remains in control. Clear skies and light winds will result in another chilly night although probably not as cool as tonight as airmass moderates. Lows will be mostly in the 50s. Patchy late night radiation fog possible again.
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&& .LONG TERM /WEDNESDAY THROUGH MONDAY/... Highlights... * Warmer and more humid Wed thru Fri * Dry much of this week except a risk of T-storms Thu ngt/Fri * Dry and less humid weather may return next weekend Overview and model preferences... After a brief cool down Tue night the subtropical ridge builds northward up the eastern seaboard resulting in a warming trend and more humid conditions Wed through Friday. Good model agreement on next northern stream trough arriving around Fri. This trough will erode the northern edge of the subtropical ridge over the area resulting in lowering heights and a return to less humid weather and near seasonable temperatures next weekend. Details... Wed and Thu ... high pressure moving offshore with return flow yielding low level warm advection. This will result in highs warming into the mid and upper 80s...possibly touching 90 Thu with warmest readings away from the south coast given onshore winds. Humidity still comfortable Wed with dew pts in the 50s but rising into the 60s by Thu. Fri ... Good model agreement on next northern stream short wave traversing the region during this time...Thu night into Fri. Forcing for ascent appears weak along with marginal shear and instability. Thus for now at this time range slight chance and chance pops seems reasonable. It will be warm and humid ahead of the frontal passage. Saturday and Sunday ... Good agreement among the ensembles /both EPS and GEFS/ high pressure building into the northeast. Thus at least avg forecast confidence on this portion of the forecast. So trend here is for temps not as warm as Wed - Fri timeframe along with less humidity. && .AVIATION /18Z MONDAY THROUGH SATURDAY/...
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Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Tuesday Night/... Through 00z. VFR. NW gusts to 25 kt. Tonight through Tuesday night...High confidence. Winds diminish this evening and VFR conditions persist. Some patchy late night and early morning radiation fog possible in typical fog prone locations. KBOS Terminal...High confidence in TAF. Seabreeze should develop Tue afternoon. KBDL Terminal...High confidence in TAF. Outlook /Wednesday through Saturday/... High confidence in a stretch of mainly dry VFR weather. Sea breezes most likely mid-late week.
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&& .MARINE...
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Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Tuesday Night/... Tonight...Moderate confidence. Expect another pulse of gusty NW winds this evening, mainly eastern waters as shortwave passes to the north. Expect a period of G25kt eastern MA waters and have expanded the SCA to Nantucket Sound and Cape Cod Bay. Seas will build to near 5 ft over outer eastern waters. Winds will diminish after midnight. Tuesday...High confidence. High pressure building in from the west will result in light NW winds which will become locally onshore up to 15 kt nearshore waters in the afternoon as seabreezes develop. Subsiding seas. Tuesday night...High confidence. Tranquil boating weather. Outlook /Wednesday through Saturday/...High confidence. Wednesday through Thursday ... High confidence. Quiet boating weather as slow moving high pressure builds over the waters. By Thu SSW winds will likely become gusty near shore. Friday...Moderate confidence. Increasing SSW flow and seas, may just touch small craft criteria. Otherwise, late day risk of showers and thunderstorms over the waters.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 2 AM EDT Tuesday for ANZ231-232. Small Craft Advisory until 8 PM EDT this evening for ANZ230- 236. Small Craft Advisory until 2 AM EDT Tuesday for ANZ250-251-254.
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&& $$ SYNOPSIS...KJC NEAR TERM...KJC SHORT TERM...KJC LONG TERM...Nocera AVIATION...KJC/Nocera MARINE...KJC/Nocera

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