Overnight: Lo 47 °F
Wednesday: Hi 68 °F
Dew Point: 37.8°F
UV Index: 0.0 None
Barometer: 29.87 in
Rain Rate: 0.00 in/hr
Rain Today: 0.00 in
Rain Tuesday: 0.00 in
Visibility: 10 miles
Gusts: 0 mph
National Weather Service Boston / Norton, MA
Point Forecast Updated Wed Apr 21, 2021 3:36am EDT
A strong cold front will bring a period of showers and scattered thunderstorms this afternoon and early evening. Some storms will be capable of producing locally damaging wind gusts. Windy and much cooler weather follows behind the front late tonight into Thursday, then a warming trend Friday and Saturday. A coastal storm will likely bring rain and coastal wind Sunday followed by blustery and drier conditions Monday. Mild and dry weather expected into midweek as high pressure builds into the region.
Lo 47 °F
Partly cloudy, with a low around 47. East wind around 3 mph.
Showers And T-Storms Likely
Hi 68 °F
A slight chance of rain showers between 11am and noon, then showers and thunderstorms likely. Partly sunny, with a high near 68. South wind 5 to 18 mph, with gusts as high as 31 mph. Chance of precipitation is 70%. New rainfall amounts less than a tenth of an inch possible.
Showers And T-Storms
Lo 32 °F
Showers and thunderstorms before 1am. Mostly cloudy, with a low around 32. West wind 14 to 17 mph, with gusts as high as 32 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch possible.
Hi 47 °F
Partly sunny, with a high near 47. West wind 17 to 21 mph, with gusts as high as 39 mph.
Lo 35 °F
Partly cloudy, with a low around 35. West wind 14 to 20 mph, with gusts as high as 36 mph.
Hi 59 °F
Sunny, with a high near 59. West wind 15 to 20 mph, with gusts as high as 31 mph.
Lo 42 °F
Mostly clear, with a low around 42. West wind 7 to 16 mph, with gusts as high as 26 mph.
Hi 68 °F
Sunny, with a high near 68. West wind around 9 mph.
Chance Light Rain
Lo 46 °F
A chance of rain after 11pm. Mostly cloudy, with a low around 46. South wind 5 to 8 mph. Chance of precipitation is 40%.
Light Rain Likely
Hi 53 °F
Rain likely. Cloudy, with a high near 53. East wind 8 to 15 mph, with gusts as high as 28 mph. Chance of precipitation is 70%.
Chance Light Rain
Lo 43 °F
A chance of rain before 2am. Mostly cloudy, with a low around 43. Northwest wind around 15 mph, with gusts as high as 26 mph. Chance of precipitation is 40%.
Slight Chance Rain Showers
Hi 56 °F
A slight chance of rain showers between 10am and 4pm. Partly sunny, with a high near 56. Northwest wind 15 to 18 mph, with gusts as high as 29 mph.
Lo 42 °F
Partly cloudy, with a low around 42. Northwest wind 8 to 16 mph.
Hi 64 °F
Sunny, with a high near 64. Northwest wind around 12 mph.
National Weather Service Boston / Norton, MA
Updated Wed Apr 21, 2021 3:45am EDT
000 FXUS61 KBOX 210836 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 436 AM EDT Wed Apr 21 2021 .SYNOPSIS... A strong cold front will bring a period of showers and scattered thunderstorms this afternoon and early evening. Some storms will be capable of producing locally damaging wind gusts. Windy and much cooler weather follows behind the front late tonight into Thursday, then a warming trend Friday and Saturday. A coastal storm will likely bring rain and coastal wind Sunday followed by blustery and drier conditions Monday. Mild and dry weather expected into midweek as high pressure builds into the region. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Highlights * Slight risk for severe thunderstorms across western MA and much of CT. Expecting a line of storms to move in from the west bringing a risk of damaging wind gusts during the afternoon into the early evening. Line anticipated to weaken as it traverses eastward. Shortwave trough located over the central/eastern Great Lakes early today. The trough will lift northeastward across the eastern Great Lakes into northern New England by the evening. Southern New England will remain within the warm sector for much of the day until a cold front moves through. The surface low associated with the front will lift from PA this morning northeastward through western MA/CT into northern New England. Main concern for southern New England today is the risk of strong to severe thunderstorms. The risk is maximized across western MA/CT as highlighted by the SPC Day 1 Slight risk, but still not completely out of the question across areas further east. Expecting the low/front to provide the lift necessary for thunderstorm initiation. Ahead of the low will see southerly flow advect in upper 40 to low 50 degree dew points. Bulk shear values in the 0-6 km layer will be on the order of 40-60+ kts ahead of and along the forcing. Orientation of the shear to the forcing is mostly parallel, so anticipating convective mode to be linear. Instability values are on the order of a few hundred J/kg of MLCAPE with little MLCIN. The limited instability should be compensated for by the strong forcing for thunderstorm development today. Low level lapse rates are on the order of 6-8 degrees Celsius per km with mid level lapse rates falling in the 6-7.5 degree range. Given this setup and forecast soundings am thinking the main risk will be damaging wind gusts. Cannot completely rule out some hail, but there just isn't a lot of CAPE within the hail growth zone. Lastly, SPC indicates there is a low risk of a tornado, but am not sold on this given the 0-1 km SRH generally remains out ahead of the forcing and does not overlap. If the forcing and SRH can overlap a bit then the risk is there especially with the low LCL heights and 0- 3 km CAPE over 100 J/kg in place across western MA and CT. CAMs show a line developing near/just west of the Capital District in NY and progressing eastward. Have kept the gusty wind mention in the forecast to highlight this as there is a 40-50 kt 925 hPa southerly jet moving across the area today. Have heavily leaned toward this guidance in the forecast for PoPs, QPF, wind speeds and gusts today. Does appear that based on the timing of the front moving in that the instability will be waning, which should limit how far east the severe risk extends and that the convective line weakens as it progresses eastward. Should see some fairly good boundary layer mixing out ahead of the system moving in, which given the strong low level jet will bring another day of gusty winds. Have gone with the 75th percentile of guidance for high temperatures today given some uncertainty on how quickly mid to high clouds move in. The result is highs in the 60s for much of the region with some 70 degree readings in eastern MA. Could see a few scattered showers this morning, but the highest risk for any precipitation will be this afternoon into the evening. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Highlights * Any lingering showers/storms come to an end as the cold front exits this evening. Gusty WNW to NW winds expected in wake of the front with much colder temperatures. * Dry, but strong W to WNW winds across southern New England on Thursday. Not out of the question a few spots may need a Wind Advisory. Expecting a closed off circulation to develop at 500 hPa as it lifts into northern New England from the eastern Great Lakes/Ontario/Quebec. This feature will lift northeastward toward New Brunswick on Thursday, but southern New England will remain under cyclonic flow. At the surface will remain pinched between the exiting system and high pressure building over the Southeastern US. Tonight... Cold front moves through and will bring an end to any showers/storms during the evening. Still have leaned on the CAM guidance as there if fairly good agreement. Expecting strong cold air advection in wake of the front with 925 hPa air of -3 to -5 degree Celsius air moving in with winds of 30-40 kts. It will not be too difficult to mix this down, so have gone with the 95th percentile of guidance for wind gusts. Should see speeds of 25-35 kts with the higher gusts after midnight. Much colder with low temperatures bottoming out in the 20s across the higher terrain the low to mid 30s elsewhere. Thursday... Strong W/WNW winds across southern New England. The pressure gradient remains quite tight with the exiting system and high pressure well to the southwest. Given the setup went with the 95th percentile of guidance as BUFKIT soundings show a well mixed boundary layer. Gusts are in the 35-40 kt range for much of southern New England, so anticipate a few spots will need a Wind Advisory in future updates. Have held off for now as most locations are borderline advisory criteria at this point in time. Given the strong mixing with WNW flow. Increased high temperatures to the 75th percentile of guidance to account for some downsloping. However, with the cold airmass in place most locations will struggle to get into the mid 40s. Do have some upper 40 degree readings across the CT River Valley and eastern MA. On top of this have also lower dew points/RH values and this may lead to fire weather concerns for portions of the CWA. See the Fire Weather section below for more details on this. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Highlights * Gradual warming trend Friday into Saturday * Rain likely Sunday along with gusty winds near the coast * Blustery and mainly dry weather Monday Thursday night into Saturday... Blustery and cold conditions Thu night as strong pres gradient remains in place. Lows mostly in the mid 30s but close to 30 over higher terrain with wind chills dropping into the 20s. Still blustery on Fri with deep and well mixed boundary layer up to 800 mb supporting 25-35 mph west wind gusts but with moderating temps under abundant sunshine. Highs will recover well into the 50s to near 60 in the coastal plain and interior valleys. Then further moderation on Saturday with less wind as high pres builds to the south. 925 mb temps around 10C will support highs well into the 60s to near 70 degrees, but cooler along the south coast. Sunshine will give way to increasing afternoon clouds on Sat ahead of next system. Saturday night into Sunday night... Good agreement among deterministic and ensemble guidance of a coastal low impacting the region late Sat night into Sun evening. As expected at this time range, there is spread in the guidance with the low track but enough clustering near or south of SNE to suggest a period of heavy rain is possible. Details on timing and location of heaviest rain still have to be worked out. There is no antecedent cold air ahead of this system or during the event so ptype will be all rain. Gusty winds will also be a concern along the coast as SE low level jet ahead of the storm lifts across the region. The risk for coastal flooding will depend on timing of the low level jet and highest storm surge with respect to the high tide. The 2 tide cycles of note are the Sunday morning and Sunday evening high tide. The Sun evening high tide is the higher of the 2 tide cycles. Latest guidance suggests the surge and seas may not be built up enough for much impact during the Sun morning high tide, while winds may have shifted to NW before the Sun evening high tide. However, timing of the wind and surge is uncertain at this time range and will be important to the coastal flooding risk. Monday and Tuesday... Trend will be for improving conditions Mon with blustery NW winds. However, there is uncertainty with how quickly the closed low exits New Eng which will impact temps and shower threat for Mon. A slower solution would keep threat of showers around on Mon, especially in the east, along with cooler temps Mon and Tue. If closed low exits further to the east, warmer temps to the west will spill into interior SNE on Tue. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through 12Z...High confidence VFR with winds shifting to the S/SE. May become gusty across portions of the south coast toward daybreak. Could see some 15-20 kt gusts. Cannot rule out a few showers spreading into western MA/CT with cloud bases lowering to 5-10 kft. Today...High confidence in trends moderate in timing. VFR to start with gusty southerly winds developing by mid morning. Will gradually see MVFR and borderline IFR as showers and thunderstorms move through generally in the afternoon to early evening hours. As any storms move through could see conditions fall locally to LIFR. Have only mentioned thunder in the BAF/BDL TAF at this point in time as instability will be waning and should see the line weaken as it progresses eastward. As the cold front moves through will see winds shift to the SW/W. Gusts on the order of 25-30 kts throughout the day. Tonight...High confidence. Any showers come to an end during the evening and should see any lingering MVFR conditions improving to VFR. Winds shift to the WNW/NW and will be strong at 10-15 kts. Gusts of 25-30 kts during the evening increasing to 30-35 kts late. Thursday...High confidence. VFR with strong WNW/NW winds. Speeds of 15-25 kts and gusts of 30-40 kts. Could see some cloud bases of 4-6 kft during the afternoon. KBOS TAF...High confidence in TAF. KBDL TAF...High confidence in TAF. Moderate confidence on the exact timing of thunderstorms moving through this afternoon and how strong gusts will get as storms move through. Outlook /Thursday Night through Sunday/... Thursday Night: VFR. Strong winds with local gusts up to 40 kt. Friday: VFR. Windy with gusts up to 35 kt. Friday Night through Saturday: VFR. Breezy. Saturday Night: Mainly VFR, with areas MVFR possible. Breezy. Chance RA. Sunday: Mainly MVFR, with areas IFR possible. Windy with local gusts up to 30 kt. RA likely. && .MARINE... Have extended the Gale Warning into Thursday night as Gale Force gusts persist. Today...High confidence in much of the forecast, but uncertain on the thunderstorm risk as the line should weaken as it moves toward the waters. Southerly winds increasing to 15-20 kts by this afternoon with gusts of 20-30 kts. Not out of the question there are a few thunderstorms late in the day as a cold front approaches. Tonight...High confidence Strong cold front crosses the waters during the evening. Expect any showers/storms to end during the evening. Winds shifting to the W/WNW once the front passes. W/WNW wind speeds increasing to around 30 kts after midnight with gale force gusts of 35-40 kts. Seas increasing to 6-10 ft. Thursday...High confidence Strong westerly winds persist across the waters throughout the day with speeds between 25-30 kts. Should see gale force gusts around 40 kts. Seas between 6-10 ft. Outlook /Thursday Night through Sunday/... Thursday Night: Strong winds with gusts up to 40 kt. Rough seas up to 11 ft. Friday: Strong winds with gusts up to 35 kt. Areas of rough seas. Friday Night: Winds less than 25 kt. Local rough seas. Saturday: Winds less than 25 kt. Seas locally approaching 5 ft. Saturday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Chance of rain. Sunday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Rain likely. && .FIRE WEATHER... Strong W winds are anticipated on Thursday in wake of the system exiting the region. The strong mixing will bring dry conditions for much of the CWA with minimum relative humidities between 25-40 percent. Should see gusts around 40-45 mph at times this in combination with the relative humidities may bring elevated fire weather concerns. This will be impacted by the precipitation that falls across southern New England today. Have reached out to the fire weather partners to determine if there will be need for an SPS. Right now based on the forecast am more concerned across eastern portions of the CWA, but will need to address this in later updates. The pressure gradient remains tight with dry weather on Friday. Minimum relative humidities range between 25-40 percent once again with gusts around 30 mph at times. This will likely be another day where there could be potential elevated fire weather concerns. Stay tuned for later updates. && .TIDES/COASTAL FLOODING... Tides will be astronomically higher Sunday and especially Monday. Depending on the location of the low pressure, there could be a couple of tidal cycles impacted, first with southeast to east flow, then with north or north-northwest flow. Right now, minor coastal flooding appears possible, but over the next few days we will be watching closely for any possibility of pockets of moderate coastal flooding. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Gale Warning from 4 AM Thursday to 2 AM EDT Friday for ANZ231>235-237-250-251. Gale Warning from 6 AM Thursday to 2 AM EDT Friday for ANZ230- 236. Gale Warning from 2 AM Thursday to 2 AM EDT Friday for ANZ254>256. && $$ SYNOPSIS...KJC NEAR TERM...BL SHORT TERM...BL LONG TERM...KJC AVIATION...KJC/BL MARINE...KJC/BL FIRE WEATHER... TIDES/COASTAL FLOODING...
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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No alerts/warnings active for Southeast Middlesex County.
Alerts active nearby in: Block Island Sound; Boston Harbor; Buzzards Bay; Cape Cod Bay; Coastal Waters extending out to 25 nm South of Marthas Vineyard and Nantucket; Coastal Waters from Montauk NY to Marthas Vineyard extending out to 20 nm South of Block Island; Coastal waters east of Ipswich Bay and the Stellwagen Bank National Marine Sanctuary; Coastal waters from Provincetown MA to Chatham MA to Nantucket MA out 20 nm; Massachusetts Bay and Ipswich Bay; Nantucket Sound; Narragansett Bay; Rhode Island Sound; Vineyard Sound