Be aware of localized light icing Winter weather advisories for freezing rain on Saturday have been posted for southern New Hampshire and a good portion of Southern New England. NWS Caribou has issued the same advisory for Sunday for northern Maine. I do not expect any real concerns about travel in Maine during the daytime. However, the concern for localized pockets of freezing drizzle and/or freezing fog increases for southern and western areas into the evening and overnight. The important point here: freezing drizzle is stealthy.  One of the key signals for the potential for freezing drizzle is already here. The 3:40 AM observation from Mount Washington indicates the warm nose (+32°F / +0°C ) has been established. The Friday evening weather balloon data from NWS Gray showed it, and NWS Caribou picked it up to a narrower extent. While there is dry air to the north to keep conditions dry there, a lazy warm front is working in. While the main moisture supply stays to the southwest, there may be just enough juice for pockets of freezing drizzle and freezing fog to develop. The atmosphere is set up for it. The thing with freezing drizzle is that it is so stealthy that it flies under the radar on the precipitation charts and the data feeds for most weather apps. This is Maine. The ocean is nearby, filled with moisture and warm air. The warmer and moist air can move freely aloft while the cold air dam locks in at the surface. Impacts are likely to be localized. Shoreline communities are more likely to experience light accretion, while interior areas around open water may experience some. The risk is also present where fog develops. Areas of rain and fog Sunday into Monday Sunday 10 AM (15z) to Monday 1 PM (18z) – Expect pockets of freezing drizzle and fog early. Warm air will try to force its way in, but I expect the cold air dam will put up a hard fight in the west and the north Sunday afternoon into early Monday morning. Expect showers with perhaps a chance of thunder to work through Monday. Where there is snowpack, expect areas of fog that may reduce visibility. Rain could be locally heavy at times before ending Monday evening.  With the snowmelt and rainfall comes the risk of localized flash flooding in the brooks, rivers, and streams in the higher elevations. Temperatures will rise and could stay above freezing through Wednesday and cool down as that storm departs. I don’t expect any widespread issues, but the rivers will rise and may trigger flood warnings from runoff and the potential for ice jams. Outlook through the first full week of January Wednesday, January 1st 7 AM (12z) to Saturday, January 11th 1 PM (18z)- An extended loop here from the European’s AI-generated forecast system showing 500mb heights and mean sea level pressure. After the New Year's Day storm passes, cold air returns to the region. Strong ridging to the west sends a trough deep to the east. Guidance ideas are presenting an amplified pattern with storm chances and the risk of some deep cold heading into the second weekend of the month. Operational ideas are going bonkers with big snow ideas, but they do that in the long-range this time of year.  From the ensemble's point of view, the operational ideas seem like a lot of noise with little substance. This 15-day precipitation anomaly presented by the European ensemble looks at the period as being rather blah, with near-average precipitation expected.  Looking at the snow potential, the ski hills are likely to rebound from the losses incurred with this week's warm-up between man-made and natural snowfall. The forecast pattern suggests that cold air will be around, which is good news for snow lovers and those whose businesses depend on it. I’d like to see the blocking over the Atlantic shift west over Greenland to get something of value or significance, and that may happen as long-term ideas tend to be a bit too far east. If the trough goes deep into Florida, as some ideas suggest, it may cause storms to stay south and east, pending on the axis. Winter is likely to gear up. Keep your heat resources stocked and filled. Make sure your storm supplies are ready to go. Top off the windshield washer solvent in the car. Stay tuned to the forecast. Temperature and outlook into next weekAfter Monday's storm passes, New Year's Eve appears precipitation free and mild. Our next storm arrives on New Year's Day and bring another round of rain, with snow showers on the backside heading into Thursday. We head back to the cooler and see how the storm pattern evolves after that.  Check The PTW Weather Wall the morning |
Mike Haggett
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