Winter Weather Advisory posted the interior Mid-November storms traditionally are on the sloppy side, and that is what is expected with this one. For areas southwest of the mountains, this is a quick overnight hitter. Eastern areas see conditions improve Sunday afternoon, but the snow machine continues for the north well into Monday.  Saturday 7 PM (00z Sunday) to Monday 7 PM (00z Tuesday) - An upper-level trough from the northwest slams into a ridge passing through the region and fires up an ocean storm. The warm front attempts to overrun the cold air in the process. It sweeps what is meteorologically known as a baroclinic zone (leaf) through the area during the overnight hours from Saturday night into Sunday morning. The trough turns sharply negative against the ridge, the surface low intensifies and reaches the Bathurst, New Brunswick region by Sunday night, becomes occluded (mature), then gradually weakens as it drifts to the east on Monday.  Overnight travel is expected to be challenge over the western part of the state, and roads will deteriorate over the north and eastern interior. There could be some moderate banding that may take place that may drop upwards of 1" of wet snow in an hour, and allow the risk of freezing rain to work into the western interior as maritime air injects in.  Saturday 7 PM (00z Sunday) to Monday 1 AM (06z) - A look at potential temperatures in degrees Celsius for contrast of below freezing (gray scale) and above (blues and reds) indicates the warm air intrusion from the ocean. I suspect that cold air damming is going to hold in the valleys protected from the southeast airflow, and that is where the risk of light icing ( ≤0.1" ) is expected to take place. What ice forms will be near the end of precipitation for the western interior. Given the track (you can see it hugging the coast into the Bay of Fundy) and intensification of the developing storm, I do expect enough warm air to move inland to melt off ice during the day on Sunday. A trailing cold front enters the western and southern areas Sunday night. While I expect most areas south of the mountains to dry out, any remaining standing water is likely to freeze overnight. I will add a footnote to this: The County, east of Route 11, runs the risk of a bit of ice on Sunday night, as warm air from the Gulf of St. Lawrence may infiltrate. A more westward track may make that happen.  A review of NWS estimates on the amount of liquid involved reveals that the north and east are the primary beneficiaries. With the ground just around freezing in the north and mountains, it may be difficult for any melting to seep into the ground. Hopefully, DownEast areas can get some benefit with ≥ ½" possible and keep the drought in check. Dry times return after this, lasting until late in the week.  I am going to be right up front here and say it's a snow-to-water (SLR) ratio nightmare for the west, south, east, and, to a certain extent, areas east of Route 11 in The County. I expect a wet snow event with SLRs 6-8:1 or less for most of the area, which will keep accumulations down. The Allagash/North Woods area is far enough north and west of the storm track to experience SLRs ranging 10-12:1. As the cold air returns Sunday night into Monday, the western mountains will see higher SLRs on the backside, reaching the 15-20:1 level, which will improve the overall amounts. The western foothills, the coastal plain, and the eastern interior could see snowflakes as a parting gift Sunday night.  Sunday 1 PM (18z) to Wednesday 7 AM (12z) - Expect the northwest wind to pick up as the storm intensifies and drags a cold front through behind it. Wind gusts in the 20-30 mph range (mountains 30-45+ with elevation). With the sub-980 mb storm slowly moving to the east, it is expected to bring breezy conditions to the region through Tuesday. Wind chills in the teens and 20s are expected for Monday, with ambient temperatures slightly moderating into Tuesday. Family owned and operated to help you recover The PTW Weather Wall updates 24/7 Your financial support keeps the lighthouse lit |
Mike Haggett
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