Significant Weather Blog: Thursday, March 5, 2026 10 AM
Wintry Mix Thursday Evening/Night into Friday Morning
This looks to be an especially interesting and challenging forecast with a variety of precipitation types expected across southern New England late this afternoon through Friday morning. Yesterday’s discussion and forecast remain reasonably on track, but there remains much higher uncertainty than usual in the details for this event.
Discussion
A relatively weak but moist wave of low pressure will move along a quasi-stationary front near the New England south coast tonight and pass offshore during Friday. At the same time, strong high pressure centered over southeast Quebec will induce a southward movement of low-level subfreezing air into southern New England tonight. Consequently, rain that should overspread at least most of southern New England this afternoon will change to freezing rain or sleet over much of the region along and north of I-90 in eastern and central MA and along and north of I-84 in CT. During tonight, the layer of cold air will likely deepen sufficiently for freezing rain/sleet to change to snow or a snow/sleet mixture across most of MA north of (and possibly along) I-90, possibly soon enough for plowable snow along and north of Route 2 in central MA and much of northeast MA (northern Middlesex and possibly most of Essex Counties). Various regional and global numerical prediction models differ on how far south the change to snow will take place. Based on experience with similar situations with strong high pressure to the north feeding cold air, am inclined to lean toward the colder solutions.
Outside of the region that may receive appreciable amounts of snow/sleet, there will be an area or two where much of the precipitation will fall as freezing rain because of rain falling through a warm layer but then freezing upon contact with the surface due to a shallow layer of subfreezing air. The most likely areas at risk for a quarter inch or so of ice accretion would appear to be the higher terrain of southwest Worcester County and the higher terrain of Hampden County (in particular the southern Worcester Hills and southern Berkshires) in Massachusetts, the higher terrain of northern Connecticut, and possibly the higher terrain of northwest Rhode Island.
Further south across southeast MA (including the Cape and Islands), southern RI, and the south coast of CT, the precipitation will likely be mainly rain possibly mixing with sleet at times, especially late tonight into Friday morning.
The region of greatest uncertainty (not that there isn’t some uncertainty throughout most of southern New England) is along and just south of a Worcester to Boston line where a slight shift in the southward extent and depth of the subfreezing layer could make a major difference in precipitation types.
Forecast
Timing: Rain will overspread southern New England late this morning and afternoon, although possibly not reaching the ground in northeast MA until very late this afternoon. The rain will likely change to a period of freezing rain or sleet across northern MA as early as late afternoon or early evening with possible impact on the evening rush hour. There remains uncertainty how quickly the mixed precipitation spreads south Thursday evening and just how far south it travels. Anticipating rain to change to freezing rain or sleet during the evening as far south as the I-90 (Mass Pike) corridor from Worcester to Boston and by late evening over southwest MA and much of northern CT. By late evening or around midnight, the precipitation will likely change to mainly snow or a snow/sleet mixture at least north of a Worcester to Boston line and possibly remain as sleet for an extended time along the Worcester to Boston corridor. Across southwest Worcester County and Hampden County in MA, the higher terrain of northern CT, and possibly the higher terrain of northwest RI, the precipitation may remain as freezing rain through most of the night with fairly significant ice accretion (up to around a quarter inch or so of ice). Across most of southeast MA, southern RI, and coastal CT, the precipitation will likely remain as rain with some sleet mixed in at times. Precipitation will move offshore by mid or late Friday morning.
Ice Amounts: Anticipate the potential for .1 to .2 inches of ice accretion along and a little south of the Mass Pike (I-90) in eastern/central MA and along/north of I-84 in CT as well as most of western MA. There may be pockets of .2 to .3 inches of ice accretion over the higher terrain of central/southwestern MA, northern CT, and possibly northwest RI. Lesser ice accretion is expected further south.
Snow/sleet Amounts: Anticipate 1 to 3 inches of snow and sleet in the corridor from Worcester to Boston and potentially as much as 3 to 5 inches of snow over some sleet to the north, especially along and north of the Route 2 corridor in northern MA and across northern Middlesex and possibly most of Essex County in northeast MA. There is perhaps about a 20% chance of pockets of 5 to 7 inches of snow accumulation across far northern and northeast MA.
Impacts: The primary impact is expected to be hazardous travel. The anticipated scenario of rain to freezing rain to sleet to snow can be especially hazardous for travel even on roads that are typically well-treated. Thus, extra caution is advised for any travel this evening through Friday morning. It’s possible that the transition to mixed precipitation will take place soon enough to impact the evening commute over northern MA. There could be a fairly high impact on the Friday morning commute over all of southern New England except southeast MA, southern RI, and coastal CT. A secondary but significant impact could be scattered tree/powerline damage from ice accretion, especially over the higher terrain of south central and southwestern MA as well as northern CT and northwest RI. We usually start to see some tree damage and powerline outages once ice accretion approaches a quarter of an inch (with more widespread tree/powerline damage when ice accretion reaches a half inch).
Next Message
This will probably be the final message for this event. All are strongly encouraged to monitor later forecasts, statements, and warnings/advisories from the National Weather Service given this is a rather dynamic situation with multiple moving parts.
For those looking for more springlike conditions, it still looks like a significant warm up by early next week with temperatures possibly reaching into the 60s.
About this Blog and Disclaimer
The National Weather Service monitors the weather 24/7 and updates forecasts, watches, and warnings as necessary. For most of southern New England, refer to your local Weather Forecast Office for the latest forecast/warning information at weather.gov/box. For information from other Weather Forecast Offices, go to weather.gov and click on the location of interest on the map.
A blog is issued when there is a potential risk of hazardous weather to southern New England and serves to provide background information regarding the significant weather with somewhat of an educational slant. In the case of hurricanes, the author will attempt to issue a message when any portion of the United States coastline may be seriously impacted. It’s intended to complement and not serve as an alternative to official forecasts issued by the National Weather Service. Readers are urged to check National Weather Service forecasts and warnings for the most timely and updated weather information. This weather message is solely produced by the listed author and does not constitute an official product of the Blue Hill Observatory and Science Center (BHOSC).
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Message issued March 5, 2026 by:
Bob Thompson
Retired National Weather Service Meteorologist
Blue Hill Observatory and Science Center Board member
