I’m a third-year atmospheric science student at Cornell University who has been blogging about the weather since 2011. While I’m not officially a meteorologist, I have accumulated a bit of experience forecasting both local weather (in western Maine and New Hampshire) as well as national/international weather during my time writing for weather.us and weathermodels.com. I also have experience programming in Python, teaching concepts in weather forecasting, and communicating forecast information to general audiences.
Snow is currently in progress over areas NE of Portland with the heaviest precip centered to the east of Brunswick. Expect light to moderate snow to end before dawn for areas to the west of Bath with snow sticking around through around 9 AM for areas to the east of there.
After snow moves out this morning, NW winds will take over and we will begin the upslope/downslope cycle where the mountains squeeze out the moisture in the air causing clouds and flurries while the foothills/coast sees all the remnant dry air and thus clearing. The moral of the story – mountain clouds/flurries, coastal sun. Temps will be in the 20’s for most with some 30 degree readings possible along the coast.
Special update this evening to cover another Norlun trough type setup that looks to bring another round of light snow tonight and into early tomorrow morning. While the heavy snow bands usually associated with Norlun troughs will remain mostly offshore, an axis of shifting winds with reasonably impressive instability and some lift too will make an appearance mainly east of Brunswick tonight into tomorrow morning.
18Z NAM Showing A Distinct Wind Shift Line (Orange Arrows/Blue Dashed Line) Over Midcoast Maine At 7 AM Tomorrow. Credit: Weatherbell
A low pressure area that brought snow and ice to the southeast US will move too far offshore to bring major impacts though a Norlun trough, basically a wind shift line, will extend to the NW of the storm bringing coastal areas some snow. Snow will be concentrated between 11 tonight and 9 tomorrow morning.
12Z GFS Showing Intense Upward Motion Over Midcoast Maine At 7 AM Tomorrow. Credit: Accuweather
While snow will mainly be light, especially west of Brunswick, some moderate to even heavy bursts of snow are likely across Midcoast areas. The map above shows intense upward motion across Midcoast areas tomorrow morning signaling bands of heavy precip are possible. The areas most at risk for heavy precip will be east of the Bath/Brunswick area.
Here is the expected snowfall from this event. Not a lot, but the driveway will once again have to be cleared especially over eastern areas.
@SurfSkiWxMan@capecodweather , it's a hybrid NORLUN.. impressive lift/instability..no question there will be +SN, question is for how long?
In case you were wondering if this event was a Norlun trough, Weir Lundstedt, one of the two ‘discoverers’ of the Norlun trough (he represents the ‘lun’ part of Norlun) confirmed yesterday evening this did in fact look to be a hybrid Norlun event.
It’s really cold out this morning. No, really cold. Temps everywhere are below zero, even at the coast. Most areas, except for the outer islands and peninsulas are in the double digits below zero and 20 below is not uncommon region wide this morning. The good news is that the wind has died down so at least we won’t have to worry too much about wind chill. Regardless, bundle up if you must venture out this morning.
Temps will continue to drop until a little after 7 and will then rise swiftly as the high sun angle contributes to more effective heating. Some mid and upper level clouds will move in this afternoon and some coastal areas could see a low cloud deck move in as well later in the day but otherwise, another bright and blue one region wide today.
One interesting little note on our temp map this morning (off NWS’s Enhanced Data Display) are the numerous, very sharp inversions. Inversions are very shallow warm layers that basically lock away patches of air at the surface and temporarily prevent them from being influenced by the rest of the atmosphere. There are several great examples of that this morning.
Wiscasset (the -21 reading in the red circle) sits at an elevation of 53 feet while Nobleboro (the -9 reading in the red circle) sits at 126 feet. While they aren’t far apart (just 10 miles) and aren’t drastically different in elevation (a mere 73 feet), the subtle differences of their locations and especially elevations have made an enormous difference in their temps this morning. Go up in elevation just a little bit and you may find it’s quite a bit warmer this morning.
More snow is coming in tomorrow though it will be mainly light. More details in posts to come.
Today will feature the passage of an arctic cold front early this morning which will cause winds to pick up out of the north west today. Temps will be dropping through the 10’s today before dropping below zero tonight. By this evening temps will be in the single digits and wind chills will be well below zero. Wind chill warnings and advisories are out due to dangerous wind chills during this time. Looking on the bright side, skies will be mainly clear today after a few morning clouds move out.
HRRR Model Showing Wind Chills Well Below Zero At 7 PM. Credit: Weatherbell
Looking ahead, our next shot for some flakes looks to arrive Wednesday. Don’t worry, snow showers and maybe some light snow is looking like the most likely outcome at this point. Warmer temps and some mixed precip are looking more and more likely for the weekend.
Today will be an interesting one for sure as our storm pulls away. This morning expect clouds with a few lingering flurries mainly over Midcoast Maine as well as York County. Any leftover snow activity should be moving out in the next hour or two so the digging out can begin. Temps this morning are mild by comparison to previous weeks, 10’s inland and 20’s elsewhere with even a few 30’s showing up along the immediate coast!
Temps will warm even more today as a cold front comes through. Let’s just say the airmass behind the front isn’t all that cold… What the front does is basically slices and dices the cold airmass that is in place this morning so that it can move out of the way (notice the warm air that tried to work in last night was met with little success). As a result, temps will rise into the 30’s for everyone with readings near 40 along the coast!
For Portland, today will likely mark the first day since January 5th that the temperature has been at or above average.
NWS Radar Image Showing Snow Moving Out This Morning
Our mild temps today do not last as another cold front moves through this evening. Winds will pick up tonight as the cold air moves in and we go back to the bitter cold. Our next chance for snow arrives Wednesday and it looks to be in the form of snow showers or maybe even light snow.
Clouds will be on the increase today as yet another storm approaches from the west. Expect a very chilly start with most areas seeing double digits below zero this morning. However, temps will warm swiftly during the day as light southerly winds bring in warmer air. Most of us will end the day in the 10’s to low 20’s.
Snow will begin in the afternoon hours and will spread east during the evening. Expect a light snow for most areas with some moderate bands working their way in along the coast in the evening hours. Inland areas see mainly a dry and fluffy snow though some wetter snow is possible early tomorrow morning. Coastal areas see heavy wet snow and then have a shot at some rain too. This combined with the snow we’ve already had this winter will put a tremendous load on roofs so please shovel your roofs off today.
HRRR Model Showing Snow Approaching From The West This Morning Before Spreading Across The Region This Afternoon. Credit: Weatherbell
By evening, everyone is seeing snow, moderate at times, with temps slowly rising through the 20’s. It will be a race between the departing precip and the warming temps to see who gets rain. Most of the precip is out of here by midmorning tomorrow and only the islands/peninsulas should see rain by then.
Almost everyone goes above freezing for the first time in quite a while tomorrow afternoon after the ‘cold’ front comes through and shifts winds to the west. This will act to mix out the cold air that is in place and thus cause temps to rise. This is because the cold air that is in place during the storm is allowed to be in place because the air is not all that turbulent. The air from 10,000 feet is not going down to 5,000 feet and vise versa. Only when the front comes through and the air is moving up and down as well as horizontally can you bust open the cold dome that is in place.
Here is my thinking as to snowfall accumulations. On the south side of the 3-6″ zone accumulations will be limited by mixing with rain/freezing rain. It should be noted that since ground temps are so cold, any rain that falls will freeze on exposed surfaces like plowed roads or driveways so beware of icy spots if rain falls.
A pretty quiet day is in store today as yesterday’s storm moves off to the east while our next one gets going well off to our south. Gusty westerly winds will continue to bring in colder air today and temps will remain steady throughout the day in the 10’s for most areas. Wind chills however will be much colder remaining below zero for most of the day.
0Z GFS Showing Subzero WInd Chills At 7 PM This Evening. Credit: Weatherbell
A messy system arrives Saturday night into Sunday with snow changing to rain along the coast. Details to come in later posts.
Our heavy snow band has developed as expected this morning and after passing through York County last night, most activity is now focused along the midcoast extending back through Lewiston. In this band expect near zero visibilities and very heavy snowfall on the order of 1-3″ per hour.
The heavy band will continue to slowly drift NE today bringing more snow to the midcoast. Attention will then turn to the upper low behind it which will likely touch off some snow squalls this afternoon.
HRRR Model Showing Heavy Snow Moving Out This Morning Followed By Snow Squalls This Afternoon. Credit: Weatherbell
As the upper low swings through, another round of heavy snow is likely this afternoon in the form of a line of snow squalls similar to summer thunderstorms (without the thunder). While the line that the HRRR depicts looks to be a reasonable interpretation of how things could unfold, I think they may be a tad more hit or miss. If one manages to find its way to you, expect a brief period of very heavy snow and low visibilities. Accumulations from these squalls will be light with a coating to an inch in the heaviest precip. Snow squall activity looks to be focused between 1 and 4 PM this afternoon followed by… you guessed it! More bitter cold winds and falling temps.
Revised snow map including what has already fallen. Should have stuck the original map… Oh well. Here’s what changed. I’ve been mentioning the uncertainty in this forecast for a while now and I’m glad I did because as with any storm, there are surprises.
Yesterday’s GFS Credit: Accuweather
Here’s yesterday’s GFS showing winds, temps, and moisture (RH) for about 5,000 feet up. Notice all the green indicating plentiful moisture. The idea that there would be plentiful moisture around allowing for precip to continue through the day as a new low formed offshore was supported by all the models and the forecast was good to go.
Today’s GFS Credit Accuweather
However, bust potential was mentioned for a reason. Anytime you get this Norlun trough type setup, there are surprises and as is par for the course, we got one. This map is the same model for the same time with the same parameters just from this morning. Notice the light greens and yellows working their way into the region. This indicates a dry slot which has shut off the steady precip over SW areas today.
Another storm is looking likely for the weekend and is looking warmer with a heavy wet snow possibly changing to rain for the coast. Our next threat for an all snow event arrives in the middle part of next week along with even more of the frigid temps we love so well.
Not much has changed from earlier updates regarding the incoming round of snow. Still a tricky forecast as whoever sits under the band the longest sees quite a bit of snow while everyone else sees much less accumulation. The storm will have two basic phases, the trough then the low. Let’s look at the trough first.
12Z RGEM Model Showing Inverted Trough Bringing Heavy Snow To The Region. Map Valid 7AM Tomorrow. Credit: Weatherbell
The first phase of our storm will involve the development of an inverted trough. While this is similar to a Norlun trough, a true Norlun event would involve a stationary band of snow whereas this band will likely move slowly east with time. Therefore it will be referred to as an inverted trough for this event.
Snow has already broken out across Southern Coastal ME with the bulk of the activity being across York County as of now. This will likely continue through this evening before activity shifts NE tonight. Snowfall rates will be very high in this band with 1-3″ per hour likely in the heaviest snow. The band will continue to develop this evening over York and Cumberland Counties before expanding inland and eastward through the morning. Midday tomorrow is when the next phase of the storm starts.
12Z GFS Showing An Active Upper Air Pattern at 1 PM Tomorrow. Credit: Accuweather
Once again, we look to the upper air map to tell us a lot about the storm. Let’s start with the dark blue circle over upstate NY/Southern Ontario. This is the closed upper low (note little black circle). This will add a snow squall dimension to the forecast especially over the mountains tomorrow. By snow squall, I really mean pockets of heavy snow as the trough should extend far enough inland to bring everyone some snow.
Next let’s focus on the green dashed line and green arrows. As a vigorous pocket of energy rounds the base of the trough tonight (yellow circle, has other implications later), the trough axis will be oriented from NW to SE, known in the meteorology world as a negative tilt which will turn the winds aloft out ahead of it to the SE (green arrows). When there are SE winds aloft, Atlantic moisture begins to become wrapped into the storm and more widespread snow soon follows. For this reason, even areas that don’t see the inverted trough band will see decent accumulations. Just a quick note, the light pink line over Maine shows the energy left over from the trough as it weakens and moves east.
The yellow circle off the coast is the final feature that I will point out on the map. Notice all the purple/white inside that circle. This is the vigorous energy that a. tilts the trough negative and b. forms a new storm off the coast. This is the second phase of our storm.
12Z GFS Showing Intense Upward Motion Associated With The Developing Secondary Low Grazing The Area Thursday Afternoon. Credit: Accuweather
Once the new low forms offshore, intense upward motion will begin across areas NE of Portland Thursday afternoon. How far west the precip builds back is still questionable though it shouldn’t get past Portland. This part of the storm will most severely impact the midcoast as the low passes east. Winds will pick up as well as the storm strengthens so watch for even more blowing and drifting Thursday afternoon and evening.
Here is my snow map, uncertainty still exists but I think someone along the midcoast sees a foot maybe a little bit more.
Today will feature an extra tricky forecast as a Norlun trough sets up. Bust potential is extraordinarily high here. As with all Norlun trough events, one town may get buried while the next town over may see flurries. Which towns those will end up being are still unknown though we can narrow it down a little bit from last night.
The trough has already set up somewhat offshore and to our south with snow extending from Providence northeastward. Radar shows snow moving ever so slightly westward however westward motion of the trough as a whole will be pretty limited today so while flakes could start falling as early as this morning, steady and heavy snow should hold off until the evening.
Here is my updated snow map. Really tricky forecast. I think the low end for the jackpot zones is 4-8″ but where the heaviest bands set up 12″+ is a distinct possibility.
More snow is in the forecast for the weekend. As for the coastal rain threat you may have heard about regarding this storm, I’m going to need a lot more model support before I buy into the idea that above freezing air makes it very far with a nearly 3 foot snowpack. More details later.
Forecasterjack 