Today will feature a mainly sunny start with fairly mild temps as cold front number one clears the coast, removing the moisture from last night (not that there was that much of it). Cold front number two blasts south today bringing the chance for heavy snow in the form of snow showers and squalls. A coating to as much as 2″ of accumulation is possible where these squalls form.
HRRR Model Giving A General Idea Of What To Expect In Terms Of Squally Weather This Afternoon. Credit: Weatherbell
Here is the general idea of how things play out this afternoon. Don’t take this too literally in terms of exactly who gets a burst of snow but know it’s definitely possible especially in southern areas. Heavy snow could briefly cause low visibility and slick up roads for the evening commute.
Another update this evening looking at a bitter cold blast this weekend which will be bookended on either side by snow threats. Let’s start with the snow threat on the front end of the cold air which arrives Saturday.
Saturday’s storm threat really hinges on how far south an upper low digs and how fast its attendant surface low develops. Right now, Downeast areas look best in terms of everything pulling together in time for a sizeable snow event. Here in Western Maine, I think this is more of a one and done blast where a quick several inches are likely to fall. The timing on this would be later in the day on Saturday though the details are still to be ironed out.
The core of the bitter cold arrives Sunday with dangerously cold temps on the order of lows around 20 below in the north, 10 below in the south. Highs likely don’t make it to 0 in the mountains on Sunday while the coast struggles to 10 above. Wind chills will remain in the -40 to -20 range region wide Saturday night into Sunday. Yeah, this is the real deal.
Next Week Storm Chance
Yesterday’s 12Z GEFS Showing The Threat For A Snow Event Next Week. Credit: Weatherbell
As the coldest of the cold retreats early next week, the door is open for more snow. My thoughts on the threat remain unchanged from Yesterday and current solutions range from ice/rain to out to sea. Here’s the graphic I posted yesterday evening that shows the spread as well as which scenario has the most credibility as of now (the snowstorm scenario). This is still a while away so things will definitely change. Be sure to stay updated as to the latest forecasts.
I thought I’d take a minute this evening to go over the next week or so of weather taking a quick look at what to expect. This will be a tale of a classic New England winter with snow, bitter cold, and the potential for a sizeable storm. Let’s start with the light snow which arrives tomorrow.
A storm will pass well offshore tomorrow but an upper low still lurks to our west. Much like with our last storm, there will be a moisture transfer between the two storms. However, both storms will be weaker this time around especially the offshore storm (weak wave compared to powerful bomb). Therefore, the same concept applies but with less snow. Spotty snow showers will impact most but they will be hit or miss. The midcoast could get brushed with a bit of steadier light snow. A coating-2″ is forecast for everyone but 3″ is possible in the mountains and along the midcoast.
Bitter Cold For Valentines Day
12Z GFS Showing VERY Cold Air Over The Region Sunday. Credit: Weatherbell
An Arctic front blasts south Saturday and frigid winds bring in very cold air behind it. Lows Sunday morning are likely to drop well below zero into the 20’s below up north and the 10’s below in the south. The map shows temps at 5,000 feet so don’t panic with the -30C temps across Maine but do realize this is the real deal with dangerous cold on Sunday. Highs on Sunday will struggle to get above zero across Maine and New Hampshire and probably won’t in the mountains. The coldest air arrives just in time for Valentines Day so plan accordingly. Thankfully, the brutal cold moves on heading into next week though it does leave us a parting gift in the form of a storm threat.
Snow Threat Returns Next Week
12Z GEFS Showing The Threat For A Snow Event Next Week
As the bitter cold retreats, a storm will likely try to form somewhere. At this point, all solutions are on the table from Rain to OTS though the general consensus is for some type of snow event. This is too far out for specifics but just know that at some point in the middle of next week, there could be a snow event.
Snow is currently falling across the region with light to moderate being the dominant intensity. Look for this to continue through the night along with high winds that will blow the snow into a low visibility, drift inducing frenzy. Amounts in your front yard will range from 0-24″ when drifts are included. The actual amount of snow that will fall from the sky is likely to be in the 4-8″ range along the coast and in the 2-4″ range inland though with drifts, amounts will be far different when you look outside tomorrow morning.
HRRR Model Showing The Evolution Of Light Snow Tonight Through Early Tomorrow Morning. Credit: Weatherbell.
Here is the HRRR model with a general idea on the evolution of the snow through tomorrow morning. I suspect it may be a little quick to shut off the snow as the upper low to our west will be eager to continue pulling in moisture. I think mid to late morning is a more reasonable stop time with drying from SW to NE.
Snowfall amounts from last night still look good with 4-8″ for most, 2-4″ in the mountains.
Snow showers are possible throughout the week as waves of low pressure develop well offshore. Another chance for respectable snow arrives early in the weekend next weekend followed by a blast of truly Arctic air early next week.
Everything is lining up as forecast and a long duration light snow event is likely today. Snow looks to arrive around noon here in Maine, a little earlier along the coast, and a little later inland towards the mountains. Not much has changed since yesterday in terms of expected snowfall. I still think the coast has the best shot at hefty snowfall amounts. Keep in mind, snow will be able to accumulate quite efficiently despite snow never falling that heavily. The good news with the light snow is that it will be easily moved by your shovel. The bad news is that it will be equally easily moved by the strong winds today that will gust along the coast to near or over 30mph. As a result, expect blowing and drifting of the snow not only that is just falling, but also of the 6″+ of snowpack most coastal areas have left over from Friday’s storm. This is likely to cause visibility issues especially for the evening commute.
HRRR Model Showing Heavy Snow Remaining South But Light Snow Impacting Maine Today. Credit: Weatherbell
Here is the HRRR model just to give you an idea of how the storm plays out in general. Don’t take it word for word in terms of individual bands or timing down to 15 minutes but look at it to get the general idea of the heavy stuff remaining south and the light stuff sitting over us for a while.
Temps today will be in the 10’s and 20’s.
Snow winds down tomorrow afternoon though snow showers will continue through Thursday as various pieces of energy rotate around an upper trough to our west.
A powerful storm is bombing out over the ocean near the Carolinas this evening and we will be on the far western edge. At the same time, a complex upper low is diving SE across the upper Midwest. They will form a connection of sorts that will transport warm moist air over the cold air moving in tonight following today’s cold front.
12Z GFS Showing Mositure Connection Between Clipper And Coastal Storm. Image Credit: Accuweather
The coastal monster will stay mainly offshore but it will throw a ton of moisture back to the NW. There is a clipper to the NW which is ready to receive this moisture and will help draw it back NW. Bottom line: there will be a feed of moisture over the area tomorrow as moisture from the coastal low gets pulled back into the clipper. If you watched my video discussing the Friday storm, you know that we need three things for snow: moisture, cold, and lift. We got the cold today with that Arctic front and above is the moisture. The problem though is the lift.
12Z GFS Model Showing Broad But Light Lift Tomorrow Evening. Image Credit: Accuweather
As the warm air providing the moisture rises up and over the cold air at the surface we got today, it will rise, cool, and condense into precip. Sometimes, this mechanism for forcing (getting air to rise) can be quite effective in producing heavy precip. Not so much this time. If you’ve followed along for a while, you’ll know that I use Vertical Velocity to show how much air is rising and thus how heavy precip will be. In the big storms, you’ll often see bright purples and reds (notice scale on right of image). This time, we see yellows and oranges. This is indication that there will be less mesoscale banding and more broad lighter precip. Therefore, look for lighter snow though it will last long enough for fairly heavy accumulations.
This snow will be light and dry which is nice for shoveling but will be unfortunate because the gusty winds will have no problem blowing around the light, fluffy snow. For this reason, expect blowing and drifting snow to cause visibility issues especially tomorrow afternoon (map valid 1PM tomorrow). Winds are likely to range from near calm in the mountains to over 30mph at the coast.
Here’s what I expect in terms of total snowfall. Keep in mind, this falls over a near 30 hour period from late morning tomorrow through Tuesday afternoon. Slow and steady is the name of the game for this one.
After a nice little storm today, we turn sunnier and cooler tomorrow as low pressure moves east. Another low is already developing in the Gulf of Mexico and will be moving offshore well to our SE Monday. Normally, this would be a slam dunk miss but a strong upper low will be driving SE and there’s a lot of energy on the leading edge. Surface low pressure will develop over the Great Lakes in response to the upper low and a surface trough will develop between the Great Lakes low and the offshore low. This sets up a tricky forecast for Monday as this trough could take on some Norlun traits leading to narrow and possibly heavy snow bands.
12Z GFS Showing A Very Favorable Setup For A Norlun Event. Image Credit: Accuweather
Looking at the 500mb setup, there are a lot of things going for a Norlun event. A strong upper low is moving in from the NW and on the leading edge, a strong peice of energy is moving right over us. Also, being ahead of the upper low, the flow aloft is divergent. To put this in simpler terms, the air at 20,000 feet is spreading out. This leaves a void that air from below must rise to fill. Think of what happens when you pull your hands apart on the surface of a lake or bath. Water rises to replace the water you pushed to the side. This rising motion helps generate precip. This is how everyone will see a coating to an inch or two of snow tomorrow night into Monday morning. The real fun is along the southern coast with a Norlun trough.
At the surface a storm will blast by well SE tomorrow. Another weak wave will develop over the great lakes. The link between the two will manifest itself in the form of a Norlun trough extending NW-SE across the area. Everyone sees light snow from synoptic (large) scale divergence aloft but any moderate snow amounts will be dominated by a mesoscale (small) norlun trough. These troughs generate narrow, heavy snow bands (think lake effect type) that can drop moderate to heavy accumulations in one town while the next town over sees some flurries and maybe a coating. My point here is that uncertainty is quite high.
Graphic Showing How A Low Forms Off The Maine Coast With Strong West Winds. Credit: Me
Another thing to watch out for with Norlun type events is the threat for a mesolow to develop. Mesolows are caused by rising air along and near the trough and also westerly winds accelerating and veering as they move from a high friction environment (over land) into a low friction environment (over water). Imagine the right front tire of your car running into a patch of ice. As that tire moves from a high friction environment (pavement) into a low friction environment (ice) it accelerates while the left front tire is stuck on the high friction pavement and can’t move as fast. The result is your car spinning out. The same thing happens with air moving from over land to over water. Above I’ve drawn up a quick graphic showing how west winds and a cold airmass emerging over water can generate a low. The divergence aloft and strong upper energy aids in this process. This doesn’t happen behind every cold front because often the air is and sinking. The air monday will be rising due to the approaching upper low/divergence which will help with the development of the low.
12Z CMC Showing The Potential For A Mesolow Along The Coast Monday Afternoon. Credit: Weatherbell
The 12Z CMC shows this potential well. Should this occur, most of the coast could see a moderate snowfall and amounts would be slightly less dependant on the fickle Norlun. While most models don’t show this, based on warm waters (still over 40 degrees!), rising air ahead of the upper low, the strong energy aloft, and the movement of the surface airmass, I think there is a good chance some sort of mesolow develops and strengthens tomorrow afternoon.
Here are my thoughts for snow. This is tentative as Norlun troughs are notoriously fickle. I’ll have another update tomorrow morning.
We’re still on track to receive a sizeable storm tomorrow as low pressure moves up the coast. The trends this afternoon have been towards low pressure being slightly farther east which would mean slightly cooler temps along with slightly less total precip. Overall, this leads to little shift in terms of how I think things play out but there are a few important differences. These differences mainly revolve around how things play out at the coast and just inland.
Looking at observations this evening, the forecast mainly looks good. A coastal front is forming across York County and will continue to sharpen up as low pressure develops offshore. The GFS shows this well. Keep in mind, models have had a very difficult time with this storm so don’t take any of the model graphics I post verbatim. They’re just to illustrate an idea not an exact figure or forecast.
Temps on the warm side of the coastal front are already above freezing over Coastal York county. Winds are off the water there and thus temps will continue to rise through the evening. Wherever that sets up, look for rain on the SE side and snow/freezing rain on the NW side. As always, snow amounts could be bumped up a few miles NW of the front as clashing warm and cold air will increase lift/forcing.
12Z GFS Showing Modest Forcing For Heavy Precip Tomorrow Morning. Credit: Accuweather
While dynamics don’t look crazy for this event, there is modest forcing for heavy precip tomorrow morning through midday. As this map shows, bands are likely to extend well into the mountains. Don’t worry at the coast, precip will be moderate to heavy there too but driven by different factors. The heavy precip will assist in dynamic cooling which will further assist cold air in moving southward tomorrow midday. I think everyone sees accumulating snow tomorrow afternoon/evening even areas that see rain for most of the event.
I’m sticking with my snow map for now as I don’t have the flexibility for adjustments and it still looks good. The jackpot will fall in the southern mountains and northern foothills with lesser amounts north and south. The one area to watch for higher amounts will be the southern end of things towards the coast. There is more liquid available at the coast but less cold air. If the cold air can show up, that extra QPF (Quantitative Precipitation Forecast) could allow for bust potential.
I’ll have updates when I can this evening on Twitter and another blog update will arrive tomorrow morning.
Not a lot has changed from this morning in regards to tonight’s forecast. Snow is ongoing across the area now but big accumulations will hold off until after around 9 PM when a very heavy band looks to sweep NE. As it does so, it will be intensifying and slowing down.
HRRR Model Showing Intense Snow Sweeping NE This Evening. Credit: Weatherbell
The farther NE you go, the heavier the band will be and the longer it will last. In this band, look for very intense snowfall rates of 2-4″ per hour along with gusty winds and potentially thunder. It won’t last terribly long for most, maybe an hour or two, but in that time, the snow will really pile up. If you are driving late tonight look for very dangerous driving conditions with near whiteout conditions. Thankfully, the worst of the storm will be from 9PM to around midnight. After that, the snow abruptly shuts off and NW winds pick up. Some snow showers could linger through tomorrow morning especially in the mountains and NE.
I still like my snow map from this morning. Remember, most of this falls in just a few hours late tonight. It will be quite a show if you happen to be awake for it!
Be careful tomorrow as winds will be gusting near 45mph which will blow around the new snow. The greatest threat for reduced visibility due to blowing snow is inland where the snow will be fluffier.
Initially there were concerns about coastal mixing and that is still possible but observations show cold air hanging tough for everyone but the outer peninsulas. Should this change between now and when the heavy band blasts through, areas east of Route 1 could see reduced accumulations.
Believe it or not, we got another storm lined up! More snow, possibly significant, could arrive Saturday. There are significant questions so the details will have to wait a while but know the potential is definitely there! Welcome to winter the way it should be!
A jucier than normal morning post today as the forecast for this evening is fascinating and very complicated. Before the snow arrives, look for increasing clouds with highs in the 20’s inland, low 30’s along the coast. Snow should arrive around 4 PM or a little after, then things get interesting.
0Z GEM Showing The Setup. Image Credit: Weatherbell
The setup from yesterday evening’s post remains largely the same this morning. Low pressure currently over Michigan will move E into southern Ontario this afternoon. Secondary low pressure will develop to our SW and move NE east of us. How fast this low develops is the key to the forecast. The general idea is that the combination of tons of upper level energy, warm ocean waters, and a favorable upper level setup (VERY negatively tilted trough for those that understand) will lead to rapid development just offshore.
0Z GEM Showing Intense Banding Across Western Maine Tonight. Credit: Accuweather
Intense snow bands will begin to develop along with the low but when and thus where these bands develop is still an unknown. We do now have a slightly better idea of where to look for the heaviest snow, the lightest snow, and where it could go either way. This is a very complicated situation and I mean it when I say there is high bust potential here. With that being said, I doubt York County sees much more than 2-4 or maybe 5″. It looks like things pull together just a little too late down there. The Midcoast and areas NE of Augusta/Auburn are likely to see a solid 6-10/8-12″ snow. It’s the areas in between that are really tricky.
This is what I anticipate snow amounts to look like. Uncertainty is very high especially NE of York County and SE of Augusta.
Even in areas without much accumulation in terms of raw numbers, expect difficult travel as the snow will fall very heavily. There is also the chance that those in the heaviest bands see thundersnow this evening as well.
The immediate coast could mix with rain this evening before the heaviest stuff arrives. If this happens, watch for a rapid refreeze which would cause dangerous travel in those areas. Right now I think the peninsulas are most at risk for this but anyone east of Route 1 should be watchful.
Snow moves out tonight leaving a cold and gusty wind for tomorrow.
Forecasterjack 