Point Forecast Updated 1:23 am EDT Jul 18, 2018
Slight Chance Showers
Lo 67 °F
A slight chance of showers. Mostly cloudy, with a low around 67. Calm wind. Chance of precipitation is 20%.
Hi 83 °F
Sunny, with a high near 83. Northwest wind around 9 mph, with gusts as high as 20 mph.
Lo 56 °F
Clear, with a low around 56. North wind around 6 mph.
Hi 80 °F
Sunny, with a high near 80. Light and variable wind becoming north around 5 mph.
Lo 60 °F
Clear, with a low around 60. Southeast wind around 5 mph becoming light and variable after midnight.
Hi 85 °F
Sunny, with a high near 85.
Lo 60 °F
Mostly clear, with a low around 60.
Hi 83 °F
Sunny, with a high near 83.
Lo 62 °F
Partly cloudy, with a low around 62.
876 FXUS61 KBOX 180737 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 337 AM EDT Wed Jul 18 2018 .SYNOPSIS... Scattered showers linger along the S/SE coast into the morning hours ahead of a sweeping cold front. Otherwise dry weather is anticipated the rest of the work week into Saturday along with much lower humidity, including warm afternoons and cool nights. Unsettled weather in the form of showers return Saturday night/Sunday and continues into much of next week along with increasing humidity. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 230 am update... Scattered showers continue ahead of a cold front continuing to push SE towards the coast, reaching by morning. Additional wave activity through cyclonic flow associated with an attendant H5 trof axis. Ascent acting upon available moisture out ahead of the front, plenty of which, lending to shower activity. Hardly any instability, have removed thunder, if any, isolated rumble. Expect shower activity to push SE towards the coast into morning, lingering into the mid to late morning hours longest for locations such as Nantucket. Biggest headaches revolves around cloud cover and fog. Forecasting either has been a struggle with no one piece of forecast guidance verifying. Obvious is scouring NW, however slow, lending to a later- forecast process of partial clearing lending to radiational cooling and potential valley fog development. So long as mid to high level clouds linger, the opportunity for shallow ground fog is limited. Noting fog outcomes out towards the Susquehanna and Delaware River Valleys in NE PA and Mid-State NY. If clearing proceeds within the CT River Valley, would expect not long after shallow ground fog issues. As to SE New England, ahead of the cold front, moist, tropical air- mass remains. Surprising light surface winds, however breezy NW per vertical wind profilers at H925-85. A measure of mechanical mixing must be ongoing preventing lower ceilings from developing keeping them roughly 4-10 kft. Wedge of drier air noted in RAP RH fields at such levels, also noting differences between ALY and CHH 0z soundings. However model forecasts continue to signal low conditions enveloping the Cape and Islands towards morning. Not an incredible amount of confidence, nor in rain chances as well. Have to simply watch, wait and see. Today... Clearing SE with a cold front pushing offshore, becoming dry and pleasant. Surging lower theta-E / drier air with precipitable waters dropping down around 0.50 - 0.75 inches. H85 cold air advection as well, temperatures dropping from +14 to +10C. This allowing a well-mixed boundary layer up to H8, mix down of faster winds, drier air. Looking at N/NW winds around 10 to 15 mph with dewpoints dropping around the low to mid 50s, some locations NW in the upper 40s. Few to scattered clouds, strongest winds out towards the Cape and Islands with potential gusts up to 20 mph. Highs around the low to mid 80s. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... Tonight... Perhaps some lingering clouds, otherwise mostly clear with light winds allowing for radiational cooling. High pressure in control. Looking at lows down around the low to mid 50s. Given antecedent rains, dewpoints mixing out at max heating of the day near forecast lows, can't rule out patchy, shallow ground fog, especially in sheltered interior valleys and notoriously prone areas. Thursday... Slightly cooler and drier conditions compared to today. Mostly clear with high pressure. Light winds. Altogether, highs around the upper 70s to low 80s, few to scattered clouds, allowance of sea-breezes along the shores towards mid to late morning. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... 330 AM update... Highlights... * Very pleasant weather w/warm afternoons & cool nights thru Sat * Showers/storms and humid conditions return Sat ngt into next week Overview... 18.00z ensembles (ECENS & GEFS) in good agreement on ridging developing over the northeast Fri and lingering into Sat. At the surface this translates to 1020 mb high over New England Fri and then drifting into the northwest Atlantic Sat, however ridge axis extends back into New England. This will provide very pleasant dry weather with comfortable humidity Thu night into Saturday. However by Sat night/Sunday ensembles and deterministic guidance in good agreement on a pattern change with mean mid level trough axis developing across the Great Lakes and OH Valley. This sets up deep moist S-SW flow along the eastern seaboard sending a tropical moisture stream from the lower latitudes into New England beginning Sat ngt/Sunday and continuing into much of next week. Thus a wet but warm and humid pattern for our region. Temperatures... 850 mb and 925 mb temperature anomalies are near normal Fri and Sat so expecting seasonably warm temperatures during the day. As for the nights, given the dry airmass in place with PWATs -1 to -2 standard deviations, light winds and mostly clear skies will provide radiational cooling conditions and support overnight lows in the 50s. Given this setup will lean toward the cooler MOS guidance for min temps. Fri likely the warmer of the two days with highs well into the mid 80s. High pres overhead Fri will yield afternoon seabreezes keeping the coastline a bit cooler. Still warm Sat inland with highs 80-85 but 70s for the coastline given synoptic scale flow will support southeast winds. Not as warm Sunday with onshore flow and showers likely. However it won't feel that cool with dew pts 65- 70. As for next week seasonably warm temps expected (highs 80-85) but with humid airmass over the region overnight lows will be warmer than normal with lows 65-70. Precipitation... Ridging provides dry weather Thu night thru Sat. Then late Sat night and especially by Sunday negative tilt mean trough sets up from the Great Lakes into the OH valley. This yields deep moist S-SW flow along the eastern seaboard into New England. This will result in showers from time to time Sat night/Sunday into much of next week. Heavy downpours possible too as PWATs climb to +1 to +2 standard deviations. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Thursday/...6z update. Into morning...Moderate confidence. NW LWM-ORH-HFD expecting partial clearing towards morning which may contribute to shallow, patchy ground FG in interior, valley terminals. SE IJD-PVD-BOS, especially closer to the coast, monitoring closely the potential for IFR-LIFR CIGs BKN004-008 that linger as late as the mid to late morning hours for ACK. Otherwise light winds increasing out of the N/NW towards morning. Generally VFR. Today...High confidence. Last MVFR-IFR lingering along the Cape and Islands into the morning hours as winds shift N/NW, becoming breezy. VFR. Strongest winds over the Cape and Islands with potential gusts up to 20 kts around 15-21z. Tonight...High confidence. Light winds. Mainly VFR. Focus on interior, sheltered valleys for potential shallow, MVFR-LIFR ground FG. Thursday...High confidence. Light winds. VFR. Sea-breezes along the shores developing towards mid to late morning. KBOS Terminal... Hold with a mix of MVFR-VFR into the morning push, improving thereafter. Lower confidence with respect to IFR. KBDL Terminal... So long as mid-high level CIGs remain, lower chances of any VSBY issues with respect to shallow, MVFR-IFR ground FG. Should mid-high CIGs clear, greater concern with respect to VSBY issues. Outlook /Thursday Night through Sunday/... 330 AM update... Thursday Night: VFR. Patchy FG. Friday through Friday Night: VFR. Saturday: Mainly VFR. Saturday Night: Mainly MVFR, with areas VFR possible. Breezy. Chance SHRA. Sunday: Mainly MVFR, with areas VFR possible. Chance SHRA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Thursday/...High confidence. 230 am update... Into today... Cold front sweeping offshore towards morning with scattered showers lingering. SW flow in advance, generally around 10 kts. With passage, could see brief N gusty winds 10-15 kts with gusts up to 25 kts. Seas remaining below 5 feet. Tonight into Thursday... Beneath the influence of high pressure, generally light N winds, 5-10 kts. Onshore sea breezes developing during the mid to late morning hours on Thursday along the near-shore. Seas remaining below 5 feet. Outlook /Thursday Night through Sunday/... 330 AM update... Thursday Night through Friday Night: Winds less than 25 kt. Saturday: Winds less than 25 kt. Seas locally approaching 5 ft. Saturday Night: Winds less than 25 kt. Local rough seas. Chance of rain showers. Sunday: Winds less than 25 kt. Areas of rough seas. Chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...Nocera/Sipprell NEAR TERM...Sipprell SHORT TERM...Sipprell LONG TERM...Nocera AVIATION...Nocera/Sipprell MARINE...Nocera/Sipprell
Note: Rain measured automatically by weather station. Rain totals do not necessarily include melted frozen precipitation.
For more accurate, manually measured rain data, see the Local Precip Data page.
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14 hours 54 minutes
Waxing Crescent (34%)