Quick update on the weekend storm based on the most recent data.
Overall, the forecast hasn't changed with this weekend's storm from what I posted earlier today.
Snow still looks to begin across the entire area during the late afternoon hours of Saturday, probably in the vicinity of 4 to 5 pm or so.
The snow is then expected to continue right through not only all of Saturday evening, but probably through and just beyond midnight Saturday night. In addition, the snow is expected to be moderate to perhaps heavy in intensity at times throughout Saturday evening.
As we get into the late night hours of Saturday night and the early morning hours of Sunday, some above freezing air at about 5,000 feet above ground level will try to start pushing into the area. This will cause the snow to change to freezing rain and sleet from south to north probably between the pre dawn hours of Sunday morning and just after sunrise Sunday morning.
How quickly the snow changes to freezing rain and sleet continues to be uncertain. The question lies with whether the changeover line will get beaten back for a little while early Sunday morning due to some very cold air that will be seeping into the area from northern New England.
Based on the most recent data available, I still think that the snow will change to freezing rain and sleet from south to north across the entire area between about 4 am and 8 am Sunday morning.
Forecast Snow Amounts From Late Saturday Afternoon Through Saturday Night: Snow totals are expected to range from will range from 3 to 5 inches for areas near and south of the Mass Pike as well as across the lower Pioneer Valley, including the Springfield Metro to 5 to 7 inches or so of snowfall accumulation across areas north of the Mass Pike, including the Worcester Metro as well as across the middle and upper Pioneer Valley.
A Long Duration Freezing Rain Event Is Still Expected Throughout The Day On Sunday That Lasts Into Sunday Evening: Freezing rain with some sleet mixed in will be occurring across all of Western and Central Mass throughout Sunday morning. Because of this, I expect there to be extremely treacherous travel conditions across the entire area throughout Sunday morning.
The big question continues to be whether the freezing rain changes to rain or not as we get into Sunday afternoon and if it does, how quick will this changeover occur. These parts of the forecast remain quite uncertain.
The latest high resolution model guidance are not in good agreement regarding the evolution of whether the freezing rain will change to rain or not.
One model (HRRR model) forecasts a fast changeover to rain as soon as late morning Sunday for most areas, except the northern Worcester Hills where freezing rain hangs on through Sunday afternoon and Sunday evening. Given the cold air damming signature in the data, I suspect this model might be too warm.
Another high resolution model (NAM model) is showing a slower changeover from freezing rain to rain with areas west of I-190 taking until late afternoon Sunday to change to rain. This model keeps the northern Worcester Hills cold enough so that it remains as freezing rain throughout Sunday afternoon and Sunday evening.
At this point, I think the area that has the greatest chance of changing from freezing rain to rain by early Sunday afternoon will be across the lower Pioneer Valley and across far eastern and southeastern parts of Worcester County.
For other areas of Western and Central Mass, including the Mass Pike from Palmer eastward to about Auburn, the I-84 region, the Worcester Metro and all of the towns in the Worcester Hills, the changeover from freezing rain to rain may occur about mid to late afternoon Sunday. Although, it may remain as freezing rain through all of Sunday afternoon and Sunday evening across the northern Worcester Hills.
For the middle and upper Pioneer Valley, the precipitation may stay as freezing rain throughout all of Sunday afternoon and Sunday evening as cold air near the surface remains locked into the region.
Forecast Ice Amounts During Sunday Into Sunday Evening: This continues to be the most difficult part of the forecast. At this point, I do think that we are looking ice amounts that range from around one tenth of an inch across the lower Pioneer Valley as well as across far eastern and southeastern parts of Worcester County to about one quarter to perhaps one third of an inch of ice across areas near the Mass Pike, the I-395 corrdor, the Worcester Metro, areas right along I-190 and across the middle Pioneer Valley.
For the Worcester Hills west of I-190 as well as across the upper Pioneer Valley, ice amounts of at least one third of an inch to perhaps one half of an inch continues to look possible. This is the area that has the highest chance of seeing downed tree limbs and power lines from the weight of the ice on trees and power lines. That said, this still looks to be about a moderate icing event for these areas.
Travel conditions throughout late Saturday afternoon, all of Saturday night, all of Sunday and much of Sunday night will be very hazardous to extremely hazardous due to the combination of snow and then ice. I strongly urge you to stay off of the roads from late Saturday afternoon until Sunday night, if you can.
All precipitation is expected to come to an end by just before midnight on Sunday night.
Look for many more updates on this storm not only during the day on Saturday but also while the storm is occurring.
Comments