Area Forecast Discussion
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000 FXUS61 KBOX 192011 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 411 PM EDT SUN JUN 19 2016 .SYNOPSIS...
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High pressure in control through Monday evening beneath which above-average temperatures and low humidity prevail, with cooler conditions along the shores with ocean influences. Towards Tuesday morning, humidity returns briefly with a chance of showers and thunderstorms ahead of a cold front into late Tuesday. Seasonable temperatures through the work week. An area of low pressure passes to the south late Thursday, with high pressure then building back in for the end of next week.
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&& .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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Continued S winds will keep dewpoints steady if not slightly rising. Beneath the influence of a ridge of high pressure with accompanying deep dry inversion as discerned from local 12z soundings, expect that with subsequent cooling within the boundary layer and moisture pooling beneath the inversion that we`ll see a repeat of marine stratus. Focus across CT and RI into southeast MA. It is possible that the entire boundary layer could saturate. Dewpoints this afternoon were ranging around the mid 50s to which lows overnight are forecast. Should it get below such values, can not rule out patchy fog to develop and possibly be locally dense. Given the dry conditions as of late, am more inclined and confident towards marine stratus over dense fog development. Otherwise some hint of fog development in the CT River Valley in MA but feel it`s a low risk. A bit more mild with highs in the 50s. Coolest spots away from the urban centers with light winds.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
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Monday... Expect any marine stratus / fog to burn off during the early morning hours with sunrise. Thereafter, continued high pressure and S onshore flow with potential for gusts up around 20 mph which will make for potential hazards for small-boats. Mid to high level clouds filtering across the region. Leaning towards the warmest of guidance considering high pressure remaining in place beneath which heat has built and overnight lows have trended warmer the past few days. Likely the best chance of seeing some locations top out around 90 degrees. Monday Night... Cold front approaches along with the chance of showers and thunderstorms towards morning, mainly beginning after midnight. Not looking robust, scattered if anything at all as some of the near-term high-res forecast guidance suggest. Digging deeper, mid level energy is stretching out along the front absent of good dynamical forcing which remains further N. Nothing in terms of low level convergence. Aside, sufficient moisture with precipitable waters of 1.5 inches, along with decent elevated instability as the column moistens and cools. So can not rule out some measure of lift whether that be through frontogenetical forcing or ascent per mid level energy, enough to warrant chance pops of showers and thunderstorms. Thinking average amounts across the region will be less than a tenth but can not rule out localized heavier amounts if ingredients come together and conditions are just right. Then again if you believe the WRF solutions then nothing happens at all. Mild with lows around the upper 50s. Breezy southerly winds continue ahead of the front.
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&& .LONG TERM /TUESDAY THROUGH SUNDAY/...
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HIGHLIGHTS... * Lingering showers with isolated thunder possible on Tuesday * Chance for showers across the South Coast late Thursday from passing coastal Low * Cooler and less muggy conditions through most of the week into Sat OVERVIEW... Overall, 12z guidance is in good agreement for this forecast. Cold front will push through the region late Tuesday as offshore low pressure gets pushed into upper level trough. Strong ridge across the desert Southwest moving into the central Plains will keep the Northeast in a broad upper level trough through most of the period. Several shortwave will move through the flow, but with little moisture appears that dry weather will continue through the work week. Only system to watch is a surface low developing on Thursday across the Midwest moving towards the Mid-Atlantic. Both the EC and GFS are in good agreement pushing the low close enough to southern New England to bring precip to the south coast. The ensembles also show several members into southern New England so will mention precip at this time. DAILIES... Tuesday...Moderate Confidence. Deterministic guidance continues to be several hours ahead compared to the ensembles. This would push the precip through the area by Tuesday morning and exiting offshore by the early afternoon. This faster solution will keep cloud cover around limiting chances for destabilization. Therefor, the potential for strong storms seems low at this time. However, if the front stalls just west enough and instability can develop, then the chance for a few strong storms increase as 0-6 km bulk shear is near 40-50 kts as mid-level lapse rates steepen near 6.5-7 C/km. However, if this does occur then moisture appears to be lacking as K values will be quite low during the afternoon and evening hours. Still something to watch in the coming day. After the first system passes, guidance tries to spin up a surface low by Tuesday evening/night. This low appears to be far enough south to keep precip out of the region, but if the surface trough is weaker, then may need to add a slight chc of pops along the south coast. Tuesday will also start off a bit muggy as dewpoints rise into the 60s. However dry air will work its way into the region by the afternoon hours. CAA will take its time as surface trough gets held up a bit, so surface temps will warm well into the mid 80s away from the Cape and Islands. Wednesday...High Confidence. Mainly a dry weather day as mid-level trough axis pushes through the region. 500 mb heights fall to -16C. This will help steepen the lapse rates across the region and with enough mid-level moisture, could see a few iso showers. Highest confidence is across route 2, which is closest to the cold pool aloft. Otherwise low RHs and temps in the low 80s will feel quite pleasant across the area. Gusty westerly winds near 20-25 mph are possible. Thursday...Moderate Confidence. A shortwave will move though the flow developing a surface low across the Midwest. This low will move towards the Mid-Atlantic and south of southern New England by Thursday night. Appears this low is close enough to bring rain to the south coast, and perhaps up to the Mass Pike. Still a lot of wiggle room for this low, so precip chances can increase or decrease in the coming days. Temperatures will continue to feel cooler with highs in the upper 70s as cold pool aloft remains over the region. Friday and Beyond...Moderate Confidence. NW flow continues across the area on Friday and into the weekend as high pressure takes control. Dry air and seasonable temps can be expected. A brief warm up an increase in humidity is possible by Sunday as riding aloft moves overhead.
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&& .AVIATION /19Z SUNDAY THROUGH FRIDAY/...
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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 Monday Night/... Tonight...Moderate confidence. Mainly VFR. A moderate risk of IFR-LIFR stratus, possibly fog, across CT, RI, and southeast MA. Hinted potential at PVD. Developing after midnight and lasting an hour or two past sunrise. S winds with potential gusts up 10 to 15 kts along the shore. Monday...High confidence. IFR-LIFR stratus and possible fog erodes. VFR with S winds potentially gusting around 20 kts. Monday Night...Moderate confidence. Will lean low-end VFR cigs developing after midnight and continuing towards morning with the chance of SHRA/TSRA. Lower confidence concerning TSRA. Continued S winds 10 to 15 kts. KBOS TAF...Should remain VFR throughout. KBDL TAF...Will hold IFR-LIFR stratus to the E overnight but there is the possibility of it entering the airspace towards Monday morning. Outlook /Tuesday through Friday/... Tuesday...Moderate confidence. Mainly VFR conditions. Scattered showers and a iso thunderstorm Tuesday morning may result in brief periods of MVFR conditions. Otherwise anticipate mostly VFR conditions. Wednesday into Friday...High confidence. VFR conditions.
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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 Monday Night/...High confidence. Good boating weather overall though there is the potential for hazards for small boats. S winds continuing with the likelihood of gusts of around 20 kts. With tidal influence, waves are expected to be choppy at times with around 2 feet in the inner harbors and sounds, and up to 5 feet on the outer waters, especially E of MA. May need a marine weather statement to address concerns for Monday. There`s a chance of wet weather into Tuesday morning but with little impact over the waters. S winds continuing with gusts around 10 to 15 kts. Low risk of thunderstorms prior to Tuesday morning. Outlook /Tuesday through Friday/... Tuesday...Moderate confidence. Winds and seas increase as a cold front crosses over the coastal waters Tuesday and Tuesday night. Winds look to remain just below SCA criteria, but seas will increase to 5 to 6 feet on the outer waters. Wednesday into Friday...High confidence in trends, lower confidence in timing. Passing coastal low Wed morning will keep ocean waters above 5 feet on Wed. Seas will drop on Thursday before another coastal low late Thursday increases southern waters above 5 feet for Friday. Winds should remains below SCA criteria.
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...Dunten/Sipprell NEAR TERM...Sipprell SHORT TERM...Sipprell LONG TERM...Dunten AVIATION...Dunten/Sipprell MARINE...Dunten/Sipprell

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