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.
Today will feature snowy conditions for many as a coastal storm moves to our east. Snow is already falling this morning and will continue to do so through the early afternoon before tapering off. My snowfall forecast from last evening still looks good for most though short range guidance and radar trends are suggesting areas just inland could do a little better than thought due to the nature of the banding structure this morning. Temps will begin in the 20’s but will quickly rise into the low to mid 30’s which will melt some of the new snow. Roads will be slick for this morning’s commute and many schools have delayed or closed. Local media has the comprehensive lists on who is delayed/closed so check with them or your local school district for that information.
HRRR Giving An Idea On How Precip Evolves Today. Credit: Weatherbell
Episode two of winter’s last stand is later this week as a front stalls near or over us which could bring snow/sleet/freezing rain/rain depending on where it sets up. More on that in the coming days.
Our very tricky forecast remains a nail biter as the storm begins to develop off the Carolina coast. A large plume of moisture extends from the Eastern Pacific to the Western Atlantic and two disturbances are dropping in from the NW helping to form the storm. After careful analysis of Water Vapor satellite and observations as well as forecast model guidance, it seems that the more potent disturbance will likely arrive just in the nick of time for the Midcoast but a hair too late for everyone else.
A Comparison Of Observed Reality To Model Forecasts For The Same Time (5 PM This Evening). Image Credit: Accuweather and SPC
This is the comparison I’m talking about with regards to the energy blasting through the Great Lakes. Notice the disturbance (marked here by the 534 dm contour line). It is a little farther behind the NAM forecast. These images are valid at the same time (5PM this evening). This is the critical energy that, when it gets here, will tilt the upper level trough negative which will intensify the storm and bring it west. This happens just a little too late for us. Model guidance has backed off on snowfall amounts today, probably as they are sniffing this out. Given that even the most up to date guidance (18Z NAM used here) is too fast with this energy, I’ve opted to go even lower with my snow totals. Without the trough tilting negative, moisture cannot be wrapped west and precip won’t get much past the coast.
HRRR Showing Precip Arriving This Evening. Credit: Weatherbell
In terms of how this all goes down, snow will move in late tonight and be light to moderate through midday tomorrow before tapering off. Really this one only impacts the coast with the mountains and NW foothills seeing but a few flakes. Take a look at the simulated radar above. Those not in the blue (snow) during this loop likely escape with a few flakes, if any at all. The Midcoast could see some heavy snow bands as the storm passes by.
Expected Snowfall Totals
In terms of accumulation, this is what I’m thinking as of now. The Midcoast will see the most as it could get into the heavy bands and will be closer to the center of the storm. A sharp cutoff will occur somewhere near Brunswick but it will be impossible to pinpoint that until the snow is actually falling. West of that cutoff, an inch or so is expected while east of that cutoff several inches are likely. Areas near Camden/Rockland/Belfast are pretty likely to see more than 4″ and up to 6 or 7″ is possible should the banding set up right. Farther north and west, little is expected and the mountains could escape without a flake.
NWS Best/Worse Case Scenarios From This Morning.
To give you a sense of how this storm has puzzled even the pros (not just me!), here was what the NWS in Gray thought we could see in the ‘best case scenario’ and ‘worse case scenario’ this morning. This is absolutely not intended to criticize their forecast, this is to show you how uncertain this forecast is. It’s always a good idea to be prepared for the worst case scenario even if it only happens one in every ten times.
All snow wraps up from west to east early tomorrow afternoon with temps rising into the low to mid 30’s and northerly winds strengthening.
This sets up part two of winter’s last stand which will feature snow, sleet, freezing rain, and cold rain to end the week. More details on that tomorrow.
Today will feature increasing clouds, cool temps, light northerly winds, and lots of confusion for meteorologists as our next storm approaches. The first ingredient for snow is cold air and that’s the ingredient we got Friday. It will make its presence felt today as highs struggle into the mid to upper 20’s north and low to mid 30’s south. Snow should hold off until late tonight but clouds will be spreading north throughout the day.
In terms of our storm, nothing big has changed from last night’s thoughts. Guidance has unanimously indicated overnight that more snow may be in store but it’s hard to say at the moment if that’s fully true. As I mentioned in last night’s update, the forecast hinges on how quickly energy diving SE across Canada (currently approaching Lake Superior) can get here to pull the storm west. 500mb analysis also paints a similar picture. Based on that, there is reason to think that guidance pointing to a little more snow may indeed be correct. 6″ of snow is not out of the question along all immediate coastal areas and a Winter Storm Watch is up for the immediate coast due to the threat for 6″ or more of snow. The Midcoast still looks to take home the biggest trophy with 8″ of snow possible there. I’ll have a full update this evening.
Boy has this been a fun one to forecast. As one of your sources for weather information (you should always consult the NWS and local media too!), the last thing I want to do is lead you on a roller coaster ride in terms of the forecast. To flip flop the forecast each day heading into a storm is something I hate doing. I want to give you a good idea of what to expect a few days out and then fine tune the details as we approach the event. With that said, this storm has led me on a wild goose chase in that every day, everything I look to points to something different. This isn’t just the whims of the model guidance I use to make forecasts, this is observations and satellite imagery painting completely different pictures. There are many moving pieces and it’s hard to figure out where they’re all going to go and what they’re all going to do. If life was full of easy forecasts, I wouldn’t be doing this. With all that out of the way, let’s try to figure out the forecast.
Evening Water Vapor Satellite Showing Many Moving Pieces (Including Lots Not Annotated!). Image Credit: SSEC
Water Vapor satellite imagery this evening shows all the parts of our storm. I’ve marked the disturbances and where the surface low will form and where it could possibly track (approximately). The ULL over Iowa is diving SE and will merge with a weak disturbance embedded in a deep plume of subtropical moisture which is marked in Green. Their interaction is beginning to form a storm over the SE US. When they merge, the storm will intensify a little bit as it begins to move NE. The real question has to do with Polar energy dropping down from the Western side of Hudson Bay. It has until Sunday night to get all the way to NY (about 1500 miles). It’s a race against time. If that energy crosses the finish line in time, it intensifies the storm, helps tilt the upper trough negative, and in turn wraps heavy precip back into our area. If it doesn’t, the storm continues at a moderately weak intensity ENE out to sea leaving us with but an inch or two.
BUFKIT Profile For Portland Showing Approximate Start/End Times As Well As The Mechanics Of Snow Growth.
It is becoming more and more clear that this storm isn’t going to drop a lot of liquid. However, given cold temps and a reasonably solid snow growth setup (see right), the snow could fluff up enough to lead to a couple of inches despite a lack of liquid. I don’t think this will be pure powder snow, but I also don’t see it being cement. Look as much or as little as you like at the image above, it shows/explains a little what you need for snow to form and what we have. Much like a Venn diagram, where they all intersect is where the snowflakes are forming. Based on this info, expect snow to start tomorrow evening. I suspect this may be a little late as the mid level dry air isn’t too stubborn compared to some other events. Snow looks to be light to moderate through the event before ending midday Monday. The ‘heaviest’ of the snow will be during the Monday AM commute though I don’t see it being all that heavy.
My Snowfall Forecast
Here are my thoughts on snowfall. Earlier today, I was ready to pull the trigger on lower snowfall amounts but afternoon guidance and a couple of things I noticed on the WV satellite and in the observations this afternoon have led me to remain more or less unchanged with my snow map from yesterday. I cut back a little on the back edge of the precip as all indications are that this will feature a sharp cutoff. I bumped up snowfall a little along the midcoast where the heaviest snow looks to fall. While 8″ seems like a stretch, 5 and 6″ amounts seem very reasonable along the Midcoast. Unfortunately for ski areas looking to refresh the base, this one looks a little too far east. Thankfully for skiers, both Sugarloaf and Sunday River have fired up the snow guns again! With cold temps lasting through midweek next week, snowmaking will remain possible for a solid few days.
A warm up is in store headed towards the end of next week and some wild temperature swings are looking likely heading into April.
I’ll have another storm forecast tomorrow evening.
Today will feature mainly sunny skies, cool temps, and decreasing winds. NW winds behind a cold front have brought in much cooler air and we will be feeling that throughout the weekend. NW winds are still blowing this morning but will be settling down as time goes on. Look for highs in the 20’s north and 30’s south.
The Sunday/Monday storm looks to head mainly out to sea. I’ll have an update on that this evening.
Remember what I said about the track of this storm being fairly certain yesterday? Yeah, that’s not really happening. As guidance, observations, and satellite imagery give conflicting messages. it is becoming harder to formulate a forecast. There are two plausible scenarios at the moment, either the storm tracks farther east and is weaker/faster, or the storm is farther west and is stronger/slower. I’ll break down each solution below. As of now, I’m thinking that the storm stays weaker/faster.
A Weaker/Faster Storm That Tracks East
18z GFS Model Showing A Weaker Solution. Image Credit: Weatherbell
The first solution would involve a storm that develops in the SE US and moves ENE passing well to our SE and near or outside the famed “Benchmark” of 40N, 70W. The RGEM, NAM, and GFS are the big proponents of this solution and based on the sluggish strengthening of the disturbance supposed to energize the storm, I think this solution holds merit. That being said, I don’t buy the GFS verbatim. I think it’s a little too fast and weak with the storm. It grazes the coast with but an inch of snow late at night Sunday with sun returning by the Monday commute. I think a faster solution would most likely involve an inch or two at the coast and a dusting inland with the foothills and mountains remaining high and dry. This is what I’m leaning towards though with the Canadian and Euro models holding on to a stronger/farther west solution, I’m not ready to fully commit.
The other possibility is that the storm tracks more NE than ENE and moves over or just west of the benchmark. This would result in a stronger storm that arrives later and drops more snow. With some reputable guidance on board, I’m not throwing this one out yet observations and satellite imagery aren’t completely favoring it. Should this pan out, the coast would see 4-8″, inland/foothill areas 2-4″ and the mountains a coating-2″. Snow would arrive late Sunday night but would last through midday Monday as bands of snow moved onshore. Winds would also become a concern with this solution but the storm doesn’t look to be close enough or get strong enough for serious blowing/drifting.
What I Think Will Happen
My First Thoughts: Subject To Change
Here’s how I think things go down. I think the storm moves over or just outside the benchmark as it slowly strengthens. The bomb solutions of yesterday seem far-fetched based on latest guidance as well as observations. Light snow moves in Sunday night and lasts through Monday midday with light snow becoming moderate at times along the coast. The map at left shows what I expect accumulations to be. Remember, this is highly track/intensity dependent. A shift west in guidance and upper level features appearing stronger in observations will cause this map to be adjusted upward. A shift east in guidance and upper level features appearing weaker in observations will cause this map to be adjusted downward.
Hope you all enjoyed the spring/summer like warmth because it’s taking a little time off over the next week. This begins today with the passage of an Arctic front currently located over the mountains. This will drop south today and behind it, winter makes a valiant return. Look for highs to occur in the morning hours before the cold air can really get here. Highs will range from the 30’s north to low 40’s south. Skies will be partly cloudy, more clouds when the front works through this morning. There is the chance for some light rain/snow this morning especially away from the coast though everyone is at risk for some drops or flakes. No accumulation is expected aside maybe from the far northern mountains.
I’ll have an update on our Sunday/Monday storm this evening.
Just as the calendar announces the arrival of Spring, our biggest winter storm threat all season is on the horizon. While it is still 3-4 days out, confidence is increasing that a storm will form in the Gulf of Mexico Saturday and move NE until it reaches somewhere near Cape Cod by Monday morning. This track is nearly perfect for heavy snow across the area with the storm being close enough to deliver a lot of moisture and far enough away so any warm air remains well to our SE.
12Z GEM Showing The Setup For A Nor’easter Monday. Image Credit; Weatherbell
It is important to note, however, that the storm is still a good 3-4 days away. While track changes are certainly possible, it is becoming more and more likely that we do see a high impact storm beginning Sunday afternoon and lasting through Monday afternoon. Here is the 12Z GEM showing the setup Saturday morning as high pressure builds in and low pressure begins to develop. We will have plenty of cold air to go around as Arctic high pressure builds south. At the onset of the storm, temps will be in the 20’s with dew points in the single digits. That will allow for this to be a mainly snow event. Should the low track a little farther west, some mixing could be an issue so we’ll have to keep an eye out for that in the coming days but as of now, this looks like an all or mostly snow event.
12Z GEFS Ensembles Showing Reasonably High Track Confidence But Slightly Lower Timing Confidence. Image Credit: Weatherbell
Confidence in track is reasonably good. Most guidance is indicating low pressure develops in the Gulf of Mexico and moves NE to a point right near Cape Cod. However, intensity and timing are the two variables that remain uncertain. The faster the storm is, the less it can intensify and the less snow it gets even if it takes an optimal track. The slower the storm is, the longer it has to intensify and the more snow we get, assuming the same track. This is why despite moderate-high confidence in track, it remains too early to issue accumulation maps. Uncertainty is still high as to exactly how much snow will fall. However, it is looking more and more likely that this is a 6″+ event. Should a slower/stronger solution play out, upwards of a foot of snow is possible. Should a slower/weaker solution play out, amounts would likely be closer to 6″. Currently, I am leaning much more towards the slower/stronger solution though this far out it is important to keep options open.
Today will feature the spring/summer part of this week’s forecast as thunderstorms look to develop as very cold air moves in aloft. Morning fog will be clearing through the mid to late morning hours and showers look to begin popping up as the afternoon approaches. Showers will strengthen into thunderstorms which could feature small hail and gusty winds. Some of these storms could approach severe limits and the SPC has placed us under a Marginal threat for severe weather today. While things don’t look too intense, do keep an eye to the sky and be weather aware today. Highs will range through the 50’s and low 60’s with warmer temps south.
While uncertainties do still run rampant, I wanted to put out there that we could be seeing significant snow come Sunday night should a coastal storm pass close enough. I’ll have an update on that tonight but please don’t fall for any hype that will likely be running around in the meantime. As always, check with local media/NWS before changing any plans for Sunday night into Monday.
Yesterday’s little storm has moved out this morning and in its wake we are seeing clearing skies as dry air moves in. Look for clearing to be slow but steady today and by evening, most should have seen at least partial sun as temps rise into the low 50’s north and upper 50’s south.
Another round of snow/mix/rain is incoming tonight through Friday and will be showery in nature.
Forecasterjack 