Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 211953 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 353 PM EDT TUE JUN 21 2016 .SYNOPSIS...
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Seasonable temperatures are expected for tomorrow with a few showers possible. Low pressure passes just south of New England Thursday, bringing showers and cooler temperatures followed by dry and seasonable conditions Friday. Dry and very warm weather this weekend into early next week away from the coast, with a chance of showers/t- storms next Tue ahead of a cold front.
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&& .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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4 PM UPDATE... Surface cold front continues to slowly push across the region. As of 3 PM it is currently located along a line just south of PVD to GHG. This can be seen in latest satellite data per a little cu field. Otherwise dry air continues to push into the region dropping dewpoints well into the 40s resulting in good mixing up to 850mb. Many locations have gusted up to 20-25 mph. These gusts will begin to dissipate after sunset due to loss of diurnal heating. Any chance for showers to regenerate appears low at this time as the column is moisture starved. TONIGHT... Quick moving wave will move south of the area tonight and into tomorrow morning. This wave will finally push the cold front through the region tonight. A few showers are possible along the southern waters but should remain dry for the region. A very pleasant night is in store for the area. Light winds across the region with mostly clear skies will allow for some radiational cooling. Temperatures could drop into the low 50s for the typical radiators. Urban regions of PVD/BOS will stay in the 60s. Only caveat is to watch for the potential of radiational fog. Several locations received over 0.5 inches of rain and this could lead to enough low level moisture to develop fog. Have a low confidence so held off on putting it into the forecast, but something to watch.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
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TOMORROW... Very potent shortwave will move through the region tomorrow. This wave combined with cold pool aloft will yield to diurnal showers. Highest coverage will be across route 2, which is closer to the better dynamics, with more scattered showers north of the Mass Pike. Some instability will develop tomorrow which could trigger a few isolated thunderstorms, but the better chance will be north of the region where the temps aloft are cooler. Shortwave will already be moving out of the region by 18z so any precip will be confined to the morning to early afternoon hours. Appears a pleasant afternoon is on tap for the region with clearing skies and temps warming into the mid to upper 70s. A few spots reaching into the 80s. Dewpoints will remain in the mid 40s to low 50s, very comfortable! TOMORROW NIGHT... Weak ridging will build into the region as heights aloft rise. Anticipate a mostly dry night with high level clouds overspreading ahead of the next weather system. Temperatures will remain in the low to mid 50s.
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&& .LONG TERM /THURSDAY THROUGH TUESDAY/...
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Highlights... * Showers likely Thu with below normal temps * Dry and seasonably warm Fri * Much warmer this weekend into early next week with 90+ degree temps possible Sun/Mon in the interior * More humid with chance of showers/t-storms next Tue Overview... Model guidance in good agreement on the overall pattern in the extended period with longwave trof over the NE lifting NE as expansive ridge over southern CONUS builds north across Gt lakes and into New Eng this weekend into early next week. A frontal wave to the south will likely bring a period of showers to SNE Thu, then mainly dry with a notable warming trend this weekend into early next week with 90+ degree heat possible interior. Next upstream trof approaching next Tue will bring a threat of showers/t-storms. Details... Thursday... Frontal wave approaches on Thu with consensus of the guidance keeping the warm front and sfc low south of New Eng. We discounted the NAM which is too deep and too far N with low pres with unrealistically strong low level jet. It should start out dry early Thu, then showers will overspread the region as deep moisture plume and mid level lift move in. Best instability, higher theta-e air and low level jet will remain to the south where best chance of t-storms and locally heavy rainfall. However, there is some elevated instability just south of New England so can`t rule out an isold t- storm near the south coast. GFS is a bit more robust with QPF than ECMWF. We used a blend which gives potential for 0.25-0.50" rainfall. With showers moving in and E/NE flow north of the boundary, temps will be below normal with highs upper 60s to lower 70s. Friday through Monday... High pres builds in with dry weather and a warming trend. Seasonable temps Fri with coastal seabreezes, then warming temps this weekend into early next week, especially interior away from potential seabreezes. Warmest days will likely be Sun/Mon with 90+ degree temps possible in the interior valleys. Warmer ECMWF has 18-19C at 850 mb which would translate to mid 90s. GFS not as hot. Southerly flow will hold temps in the 70s along the immediate south coast. Dewpoints mostly in the 50s so humidity levels will be low. Tuesday... Another very warm day with temps well into the 80s while ECMWF shows potential for more 90+ degree heat. Dewpoints will be increasing into the 60s ahead of a cold front which will help to destabilize environment so increasing threat of showers/t-storms but this will be dependent on the timing of the approaching front.
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&& .AVIATION /20Z TUESDAY THROUGH SUNDAY/...
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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 Wednesday Night/... Before 00z...High Confidence. VFR with westerly wind gusts near 20 kts. Tonight...High Confidence. VFR through the period. Low prob for radiational fog to develop in low lying terminals across SE MA and RI. Tomorrow...Moderate Confidence. Scattered showers during the first half of the day with a low risk for thunder. Mainly VFR conditions through the period. Tomorrow night...High Confidence. VFR. KBOS TAF...High confidence. VFR. Low risk for -TSRA early tomorrow afternoon. KBDL TAF...High confidence. VFR. Outlook /Thursday through Sunday/... Thursday...Moderate confidence. Conditions lowering to MVFR with showers developing and low risk for t-storms near the south coast. Friday through Sunday...High confidence. VFR. Sea breezes likely.
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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 Wednesday Night/...High confidence. Weak cold front will push through the waters tonight switching the winds to a more westerly directions. Seas and winds will relax this evening and into tonight so have dropped SCA. Showers an iso thunder possible across the eastern waters tomorrow afternoon. Otherwise building southerly swell on Wednesday will result in seas reaching 5- 6 feet. Issued a SCA for seas where confidence was highest that this would occur. Seas will begin to relax by Wednesday night. Outlook /Thursday through Sunday/... Thursday...Moderate confidence. SW Winds becoming easterly with speeds less than 20 kt. Seas may approach 5 ft over southern waters. Friday...Moderate Confidence. North winds becoming locally onshore over nearshore waters as seabreezes develop. Lingering 5 ft swell possible southern waters. Saturday and Sunday...Moderate confidence. Light winds becoming onshore each day over nearshore waters as seabreezes develop. Seas below SCA.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory for hazardous seas from 8 AM Wednesday to 8 AM EDT Thursday for ANZ255-256.
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&& $$ SYNOPSIS...KJC/Dunten NEAR TERM...Dunten SHORT TERM...Dunten LONG TERM...KJC AVIATION...KJC/Dunten MARINE...KJC/Dunten

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