All of the players are on the table Pardon the later-than-normal update here. I’ve been up since 2 AM going over data with this multi-faceted system. There is a lot to unpack here. There is also a lot of overlap and jumping around in this discussion since all the ingredients play a role in how this plays out. Impacts will be different across the state for different reasons. The order of presentation does not necessarily indicate priority due to the complexity of this storm. This is a messy, early March system. This is typical of spring. My overall rating of impact for much of the state is moderate. We’ve seen worse storms. Fortunately, after this one, we get a break. Timing / set up Saturday 7 PM (00z Sunday) to Monday 2 PM (18z)-- Guidance ideas continue to adjust more westward. In Thursday’s discussion, I mentioned that high pressure over Baffin Island opens the door for that. The warm lead moving in ahead of the cold creates a forecasting conundrum. It is typical with spring storms for bust potential for frozen precipitation, both on the low and high end. For those cheering for snow, I suggest you taper the expectations, given the dynamics. I’d rather you be pleasantly surprised with the chance of overperformance than seriously disappointed with a low-end bust, which has been the story of winter. The storm intensifies on its way into the central part of the state Sunday afternoon, reaches maturity, and then occludes (the moisture hose shuts off due to the arrival of the dry slot) before moving off to the east on Monday. Precipitation types and potential amounts Looking at this from a liquid equivalent standpoint, it’s important to note that forecast guidance amounts are creeping upward. The higher elevations stand to get the most out of this due to the southeast wind direction throwing precipitation up against it.  Given the track of the system, I don’t expect much in the way of junk with this system. There could be quick hits of sleet over the foothills, but it may not last long. Given the warmth and the rain of late, this will be a mess to plow. With this likely to be a wet, pasty snow, it could be heart-attack level to shovel. With temperatures on the mild side post-storm, do what you need to do and let Mother Nature take care of the clean-up for you after. As with Thursday’s storm, dynamic cooling will affect snowfall amounts. As noted in Thursday’s update, the temperatures are marginal over western areas and better for accumulation in the north. With the boundary between warm and cold working well inland, there is the potential for rapid accumulation in the western mountains at the 1-2” per hour rate Sunday morning. Higher elevations may get upwards of a foot of snow where cooling is better, but the valleys are likely to get the slop. Travel on Sunday morning could be problematic in areas where snow is piling up. Power outages are possible in that region as well. Minor to moderate flooding likely south and east The storm on the way brings flood potential to the interior and shoreline areas. Recent rains and snowmelt have filled the main stem rivers. A couple of dry days on Friday and Saturday will help drain the rivers somewhat, but they will be running high. I expect flood watches and/or warnings to come with the amount of rainfall on the way. Flash flooding is possible, but it appears to be more areal. The intensity of the rainfall will dictate how this plays out. For the shorelines, minor flooding and low-level inundation is possible DownEast. For the MidCoast and southwest coast, moderate flooding and inundation are potentially there.  Sunday 2 AM (06z) to 8 PM (00z Monday) – The low-level jet and the timing of it is the key feature for impacts for the coastline. Along with that is the actual track of the storm. The timing of its arrival on Sunday morning coincides with high tide. With the southeast wind flow pushing water into the shorelines, this is where the concern for flooding and inundation comes in. The timing of the low-level jet also runs in tandem with peak wind gusts across the entire region. Hold that thought.  A look at the Extra-Tropical Storm Surge (ETSS) model output takes the timing of the peak wind into consideration. The model idea suggests that the peak of the surge hits the southwest coast at the high tide point, which will add 2-3’ to the king tide which is forecast to run around 11-12’. The surge may come in later for DownEast areas, which would spare the region of more problems. Seas are expected to run 9-15’, and this is where the potential for inundation comes in with splash-over and surge. Given the inland track and timing of the storm, the water shoved into the rivers may be slower to recede. That may keep the flooding going longer. Using the January storms as a reference point, if your home or business experienced flooding, then it’s a fair bet it may happen with this one. It doesn’t hurt to be prepared. The overall shoreline impact of all the ingredients listed here depends on what kind of defense is there or remains from the January storms. We’re in a bit of uncharted territory as to how bad the impacts may be, as some areas are more vulnerable than others. Please use your wisest discretion, and prepare accordingly. The wind factor The key areas of concern for wind are the shorelines and the mountains. I’d give the slight edge on the impact scale to the mountains given the threat of heavy wet snow. The combination of wet snow and wind bringing trees and power lines down may cause road obstruction. Peak gusts roll through the region Sunday morning for the west and south, Sunday afternoon for the north and east. As the storm track enters into central Maine, the wind direction sharply turns to the west / northwest and remains gusty through the day and continues overnight into Monday as the storm departs. It would be wise to prepare for power outages. Stay tuned for updates on all of this as the forecast is fine-tuned. Check out PTW for information 24 hours a day Thank you to Allspeed Cyclery & Snow in Portland, Downeast Aerial Photography in Rockland, Dutch Elm Golf Club in Arundel, and Sunrise Property Services in Bridgton, for partnering with Pine Tree Weather. Special thanks to all the individuals and businesses who financially contribute. I sincerely appreciate your support. Always have MULTIPLE ways to receive weather alerts. Stay updated, stay on alert, and stay safe! - Mike PRINT MEDIA: Feel free to quote and cite my work here for your stories. 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Mike Haggett
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