La Nina spreading some big wings as winter 2020-2021 approaches !!

Though it may not feel like it, we’ve managed to reach late November and the commencement of another ski season. When the SCWB signed off late last year, the worsening pandemic felt like a big black hole enveloping us with no way out. As of November, the black hole still envelops us, but to borrow (and slightly alter) one of Carl Sagan’s most famous quotes, “Us Vermonters have a certain talent for adaptability” and we will apply that adaptability to piece together a ski season while dealing with and overcoming the many obstacles.  As I see it, the weather is presenting a few obstacles as well, but its nothing we aren't used to. For those of you that will never get used to the wordy discussion, please skip ahead to the bottom and receive the less than wordy outlook !

The three months leading us into November were exceptionally normal in terms of temperature, landing .  within a half a degree of normal. There was some concern early in the summer of a worsening drought but a succession of very wet months (August/September/October) has alleviated many of those concerns. The current US drought monitor still puts us in a D1 area - Drought Monitor, but the overall water situation has improved since some very dry months in the spring and early summer. Within the vicinity of the North American continent the two most glaring aspects of weather was the persistent heat and resulting forest fires in California and the remarkable hurricane season which culminated in two historic landfalling storms (Eta, Iota) very late in the tropical season. Many will refer to the 2020 tropical season as record breaking because we blew through the alphabet and well into the greek letters. This is a little deceiving since the technology is available to better indentify weather systems that meet the various thresholds to earn an official tropical name. To see a category 5 storm strike Central America in November is nothing short of remarkable however and truly cements 2020 as a historic one for tropical activity. 

What about this La Nina 

The tropical cyclone activity in 2020, particularly the strength and unusual late presence of that activity deserves a place in the discussion about climate change (and it will certainly get one). That said, a strong and active hurricane season is pretty typical given the presence of La Nina and we’ve had a notable one since late in the summer. La Nina’s are best illustrated by a line of anomalously cold water in the equatorial regions of the Pacific and aside from the aforementioned impact on the hurricane season, can, when strong enough, have a material impact on winter weather across mid-latitude North America. So what are we looking at this year ? La Nina was gradually strengthening, reaching a value, based on a temperature anomaly of  -1.7 C in late October though it has recently subsided a touch since then. Anything under -1 is significant and were it to stay there through the winter will most assuredly have something to say about our prevailing weather pattern.  So what is that weather pattern typically ? A more concentrated storm track in the Pacific, generally north of California (they could certainly use more rain), cold weather confined to the northern tier of the US, warm, dry weather across the southeast U.S. and active weather in the northeast. Active, because usually the storm track takes dead aim at New England and can bring varying results. 

 

  (Above are some of the bigger La Nina's going back 70 or so years, some weaker but notable La Nina events not included)

I am not a fan of strong ENSO events of any kind (La Nina or El Nino) as they bring with them many risks and are infamous for inconsistency. The 70 years of data does present a rosier picture however with several weaker La Nina's yielding huge snow years and a few stronger La Nina's delivering the same. Every inch of latitude-north is important and locations south of 40 N often perform quite poorly. The results really vary across Vermont as illustrated by both attached figures and results are highly dependent on what side of Vermont does the prevailing storm track establish itself. Is this a forecaster speaking from both sides of his mouth ? Absolutely ! but the information is revealing and it makes sense. A storm track aimed at Vermont as opposed to well south of Vermont is actually a positive thing, it just doesn’t always produce positive results. In colder La Nina years, and there are several like 1970-71, 1995-96 (weak La Nina), 2000-2001 (weak La Nina), 2007-2008 and 2010-11, the results are fantastic. This is year 17 of the blog and I rank 2007-08 and 2010-11 as #1 and #2 respectively for MRG ski years and both had significant La Nina’s. Unfortunately 1988-89, 2005-2006 (weak) and 2011-2012 (weak) also featured substantial La Nina’s and were awful snow years. Either way, La Nina’s can produce up and down results not only from one season to another but within that season. It is rare to go more than a few weeks without some classic Vermont-style rain/ice catastrophe. 

 

 (This illustration is pretty worthless to the naked eye except it shows the snowstake at Mt Mansfield which is never worthless and also shows the wide variation in results during La Nina winters)

PDO/Pacific SST

So how can one determine whether we get the good or bad version of La Nina this upcoming winter. It naturally leads us into the Pacific Decadal Oscillation (PDO) part of the discussion which includes a broader overview of sea surface temperature patterns in the Pacific Ocean. The PDO phase is determined by sea surface temperature configurations in the mid latitude Pacific. When cold SST anomalies hug the western North American coastline it illustrates a negative phase with the reverse indicating a positive phase.  A positive PDO phase does correlate well to a more favorable weather pattern for east coast cold and snow but they are rare during significant La Nina winters. Officially however, we remain on the positive side of neutral going into the upcoming winter. I want to convince myself that this is a uniquely positive indicator but the data going back 70 years is inconclusive at best. Several of the snowiest winters in Vermont on this decorated list occurred with both significant  La Nina’s and very negative PDO phases. What is a forecaster to do aside from ramble on and on ! 

Autumn 2019

 

 

Autumn 2020

 

 

 

With each year of blogging and seasonal forecasting, I continue to be a fan of PDO assessments. The winters of 2014-2015 in particular was dominated by very large, sometimes record breaking positive PDO phase underscoring the predictive value of this variable in a seasonal forecast. I’ve also realized however that the nature of the PDO is also of great importance and this speaks specifically to a deeper look at sea surface temperatures in the mid-latitude Pacific Ocean. Last year, the persistent Pacific Ocean warmth stretching from the Aleutian Islands through the Gulf of Alaska left us with an invariably strong Pacific Jet and had us fending off mild air a lot more often than we would prefer. Unfortunately, much of this SST configuration remains and the blob of warmth appears especially formidable south of the Gulf of Alaska. The only difference this year would be that the aforementioned warmth does not extend all the way north into the Gulf of Alaska. Though the map seems to indicate a more negative PDO index, it remains barely positive for now on the basis of some of that warm ocean water extending all the way to the North American west coast. The continued presence of the mid-latitude Pacific warm water is the most concerning variable right now and it underscores the importance of taking that deeper dive into the PDO/Pacific SST assessment. The weather pattern seems intent on dumping a lot of colder air into that region of the Pacific over the next 14 days and it will be interesting to see if that can weaken the area of anomalous SST warmth.  

Snow Cover Expansion

We recorded another strong snow build across the northern hemisphere in November. The 21.22 millions of square kilometers observed in 2020 was the 9^th consecutive October where the land area of snow cover exceeded 20 millions of sq km. Prior to this 9-year run of strong October snow expansion, the average extent of snow cover was about 18 millions of sq km with a standard deviation of roughly 2.5. Relative to that average, all but two of the recent 9 years have been more than a standard deviation above average. To borrow the phrase from former NBA star Rasheed Wallace, “Ball Don’t Lie !“ and neither do these statistics. Either the prior  almost 50 years of data are wrong or more likely, the expansion of snow and ice in October is a byproduct of other trends and changes occurring very quickly at arctic latitudes. The obvious player here is the alarming loss of sea ice as a result of climate change which results in more open water across the Arctic Ocean during autumn and an altered snow climate across northern latitudes. I’ve had to consult with others to verify this hypothesis and I am relatively convinced this is the cause. Without getting too immersed in the weeds, this conclusion changes the way one would use this data and would indicate that the old “normal” doesn’t apply. 21.22 millions of square km is still a very strong number, especially since it is largely driven by the 10.26 millions of square km recorded over the North American continent. That said, this year’s data falls smack in the middle of what was recorded over the last 9 years and is behind what was recorded last year.

Meanwhile arctic sea ice which has, what we think, is a causal and inverse relationship with snow cover expansion been near or at record lows for much of October into early November. We have seen ice expand into the Hudson Bay in the past week or two which conforms to climatological expectations, but as a whole, sea ice continues its longer term decline and that decline is more than alarming when looking through the geological time scale lens. 

 

Atmospheric Poker Tells 

Has the atmosphere given us any poker-style “tells” this year? Some things are obviously very different this year verses last year like the emerging formidable La Nina and the many strong hurricanes. Some things are the same such as the blob of sea surface temperature warmth in the mid latitude Pacific. But how is the weather actually behaving ? We had those succession of “normal” but relatively wet months this fall and what appears to be a relatively mild November. In Vermont, the mild weather has been more garden variety but across the U.S. as a whole, it will likely go down as one of the warmest November’s on record (guessing top 5). I am particularly interested in the behavior of the Arctic Oscillation (AO) since we would all like to avoid a recurrence of 2019-2020. When aggregated over the entirety of last winter, the AO was the 2^nd highest on record and though the season wasn’t completely free of good moments, the persistence of the +AO was the elephant that thrashed the room and proved too difficult to overcome. The AO did surge early this past November, rekindling some of those bad memories but has since faded and is forecast to be close to neutral through early December. You can’t say too much from what we’ve seen so far except that we have yet to see good evidence that the weather pattern is showing a propensity to get blocked. So far it has not !! This combined with the mild turn this November and some more localized SST warmth off the eastern seaboard is a little concerning.  

 Our Winter Outlook 

The outlook is thus as follows. A mild winter can be expected on the whole, but consistent with the traditions of La Nina, there will be interludes of both very mild weather and cold and snow. What will hurt this winter, in my expectation, is the likely inability for a cold, snowier pattern to lock itself in for more than a span of 3 weeks; in fact, we may be lucky to get 3 weeks. That said, I think the winter has some things going for it. La Nina combined with a modestly positive EPO will keep the storm track pointed in our direction and even if extended periods of favorable weather aren’t expected, several broken up decent periods are likely. Additionally, we are in a much better place for snow given this set up than southern New England, the Catskills, Pennsylvania and points south. Latitude will be good and even 10 miles of Rt 100 might make a difference in certain events. I would expect the mild weather will keep snowfall below average this year but we will have our days. Again, I would be surprised to see 2015-2016 revisited. We could also surprise to the upside as several La Nina winters have done. I am shying away from a snowy La Nina forecast based on the SST configurations in the Pacific and recent behavioral pattern tendencies but it wouldn't be unprecedented or that surprising. In the end I am guessing MRG procures around 200 inches of snow.

Hope everyone has and will stay safe through the thanksgiving holiday. A special shout out to those essential folks working through the pandemic helping all of us get through this. It can't be easy and it hasn't gone unnoticed. See you all on the mountain !

Winter 2019-2020 was a long time ago. But I revisited anyway

Though we will look back at the 2020 season for too many of the wrong reasons, it still had its moments. It won’t rank as one of the better winters over the past 25 years and most certainly resides in the bottom half of that sample size. With that said, it is probably closer to the middle than the bottom and at least northern Vermont could brag about some some while other locations to the south saw hardly any. 

The above graph is from the ever-popular Mt Mansfield snow stake site. I actually prefer to take a sampling of final snowfall totals from various ski areas around the northeast (sometimes outside of the northeast) but most stopped reporting as of mid-March. “The Stake” at Mt Mansfield apparently can’t be stopped and it always proves to be an invaluable resource for weather and data enthusiasts such as myself. The color coded lines can appear a bit blurry to the eyes but the pink line is 2020 and it runs behind most years this past decade with the exception of the of 2011-2012 and the Super-Nino debauchery of 2015-2016. We were able to keep pace with 2017-2018 for a while but were unable to score another miracle March and instead recorded a rather ordinary to sub-ordinary one. The 5-week "arctic spring" is also notable. More on that below.

Choosing the one single variable that defined the personality of the past winter was easy this year. Hands down it was the Arctic Oscillation (AO). Scientists have officially been tracking that index going back to 1950 and it remains one of the best gauges we have to measure how blocked the jet stream is over high latitude regions of the Northern Hemisphere. When aggregating over a 5-month period (Nov-Mar) the AO this past winter was the 2^nd highest ever recorded. 1989-1990 remains the winner and 1990-1991 had a strong bronze medal showing but 2019-20 both intense and persistent, often challenging the confines of the graphical display while spending all but a few weeks in positive territory. Below is a chart measuring the top 5 +AO years and top 5 -AO years

When you consider those headwinds, 2019-2020 doesn’t look quite as bad. 1989-90 and 1990-91 were decidedly worse snow years based on data from the Mt Mansfield snow stake and 1992-1993 benefitted from of the greatest winter storms of all time. It also shows that Vermont can survive the adverse impacts of a +AO year a lot better than areas farther south. Winter across the Mid-Atlantic was nearly non-existent and ski areas suffered a much milder fate relative to Vermont. Atlanta, GA was nearly 4 degrees above normal over that same 5-month period. 4 degrees may not be a lot for one month but over the course of 5 months makes it one of the warmest winters on record. The same can be said with -AO winters. All 5 winters on the above chart were good snow years but the record year 2009-2010 actually featured a weather pattern that became too “blocked” and many of the best storms missed Vermont and deposited snow on the I95 corridor instead. Atlanta, GA by the way, recorded one of the coldest winters over this same period. 1968-69 was absolutely historic in Vermont and one of the best snow years ever recorded in many locations.

We also spent much of the winter talking about the persistent tightness of the jet stream in the mid-latitude Pacific Ocean. This zonal, fast to east moving consolidated jet stream mitigates the impacts of arctic air over mid-latitude North America and the index that best measures this is the Eastern Pacific Oscillation (EPO) index. The positive index which is defined by a version of this weather map is largely what we saw throughout the winter. Notice the cold over Alaska which was very prevalent through much of the past several months. 

Though the EPO was very positive through much of the winter, once I went through the rather tedious process of parsing through all the daily data I found that the positive value of around +33 was closer to zero than I would have thought. The two winters prior to this recorded values in the mean of close to -60 and the super evil empire winter of 2011-2012 recorded a value of close to +80. In other words, the EPO was an issue but the +AO, based on the aggregated data, was a bigger issue.

If I had to identify a single culprit to the persistence of the +AO/Somewhat +EPO pattern this winter it would be the configuration of sea surface temperatures in the Pacific. More specifically, the massive blob of sea surface temperature warmth that positioned itself south of the Gulf of Alaska. It was a large contributor to what became a negative Pacific Decadal Oscillation season. A negative PDO is not, in and of itself a pattern killer for snow and winter lovers in New England but the persistence of a jet stream level ridge underneath a glaring lack of blocking in the Arctic became the most prevalent adverse variable in almost every update I did this past season. Interestingly, this feature was identified in the  pre-season outlook as a concern but it was pitted against what was, at the time, a glaring lack of sea ice in the Chukchi Sea (regional body of water north of the Bering Strait). As it turned out, the Chukchi Sea quickly froze and we were left with the anomalous body of sea surface temperature warmth described above. Such a sea surface temperature setup is often associated with La Nina winters but not this time. The equatorial Pacific stayed on the Nino side of zero throughout the winter, and though we did see an energized southern branch of the jet stream at times, the weak El Nino did not greatly influence our winter season one way or another. 

November and early December saw the best stretch of pattern fundamentals and the season was off to a promising start. The high country surrounding the MRV did see several small but measurable rounds of accumulating snow and temperatures were 5-7 below normal for November which was colder than 2018. The biggest difference however was the lack of Snowvember. We were teased with the idea of big storms on a few occasions but nothing ever materialized. Thanksgiving was white but just not “deep” white. Still, the persistent cold was promising and it finally looked like the pattern would bear fruit in early December thanks to a bombing area of low pressure along the east coast. Though the storm did deliver several inches to the MRV, the heaviest snow fell across southern Vermont, the Berkshires, Albany, NY and the Catskill Mountains to the southwest. I feel like this storm was an inflection point. Had we bullseyed that sucker, and we were close, we may have remembered this winter very differently. 

Cold weather persisted in a general sense to about the winter solstice but there were two somewhat damaging thaws within the week of December 9^th to 15^th that limited our ability to establish a base. The coldest day of the season was actually December 19^th when the high temperature struggled to reach 5 but we only managed to muster a few inches of snowsqualls and had limited snowcover going into the holiday. At that point, the pattern broke down and much of what was described in the above paragraphs, a very positive AO (unblocked Arctic), a somewhat positive EPO (zonal Pacific Jet) became the prevailing influence on our weather pattern. Christmas was wintry but there were several days around Christmas that were not.

The loss of Rush drummer Neil Peart cast a dark shadow on the early part of January 2020 for me personally. Looking back, I suppose it was a lead indicator of the rough year that was to come.  On the weather side of things, the 10 days that began on around December 29 and ended around January 8^th was one of the better stretches of the season. Though the pattern wasn’t entirely supportive, a once upper Midwest blizzard deposited a mixture of snow and sleet on the MRV and provided a few days of instability leading up to New Years Day. No it wasn’t epic, but we got a bit of all of the necessary ingredients starting with a good base building storm a few a few inches of powder on the 30^th, the 31^st and on New Years Day. Temperatures crept above the freezing mark for a few days on the January 2^nd, and 3^rd but we were able to score some additional snowfall on the 4^th and procured a nice first weekend of the new decade. A few days of snow showers and squalls during the following week gave us a temporary impression that winter was resettling in. Unfortunately, this didn’t last. A very mild weekend January 11^th and 12^th and some rain put a massive dent into the base and put a crimp into the rest of the month. We got a bit of cold weather and snow in the week that followed but the big storm proved to be elusive. The best chance for one came without much cold air support on the last full weekend of the month. I remember talking about walking the proverbial “tightrope” and hoping for the perfect storm track. In the end we kinda fell off the tightrope a bit but did receive a bit of decent snow across the high country while the low elevations got a bit of wet weather. 

February was a tale of the “same story, better result”. It was historically awful for snow along the I95 corridor including all of southern New England and New York City. Boston recorded only a half inch of snow for the entire month and New York City only recorded a trace. As the AO continued to soar, nearly breaching the limits of the visual chart on two occasions, temperatures continued to run above average across much of the United States including Vermont which saw readings 3-5 above average. We did get the snow however, mainly from two different but substantial events. The first on February 6-7 was the best of the season. It was a windy event which proved to be a challenge for some resorts to manage but we got the powder, almost 2 feet of it and we got a few days of cold weather on the ensuing weekend which included a calm Sunday February 9^th. The other big event occurred toward the end of the month. It was a wetter snow event at the low elevations but an overperformer nonetheless with around a foot of snow. We had hoped to score the additional instability snow leading into the weekend but winds remained westerly as opposed to northwesterly favoring the snow over locations such as Stowe and points north. The two storms in February might have made the month a more memorable one but there was a lot of mild weather in the middle of the month. We did manage to avoid much of the rain but not all of it. 

March brought in the Covid19 pandemic so I suppose it was good year to not have our traditional mid-month snow bonanza. The first 15 days made up the last 15 days of the season for most resorts and it featured big temperature surges and occasional rainfall. It didn’t look especially good for a wintry finish to the season but it goes to show that you just never know. I am saying this completely in jest but it is almost as if the pattern waited or Governor Phil Scott to issue his stay at home order and suddenly everything fell into line. The positive AO became completely neutralized and a “well blocked” jet stream emerged. It showed up in the NAO data the best but we also saw blocking over the Yukon which fueled an amazing and persistent stretch of winter-like weather over Vermont in the middle of spring. 

Much of Vermont did see a nice overperforming wet snow of nearly a foot in some places on March 23^rd, but the true “arctic spring” didn’t commence until around April 9^th. It was 5 weeks of remarkable spring cold and some substantial snow. So much snow in fact that Mt Mansfield had a 2^nd peak of snow pack in early May. More on that later. The 5 weeks beginning on April 9^th and ending around May 13^th was roughly 7 degrees below average and much of the high country didn’t see any 60-degree temperatures throughout April. We did see several rounds of snow, some elevation sensitive, some not so much. Though we never did see the epic April powder producer (that would come in May), I would estimate that Mad River and Sugarbush saw at least 20 inches of snow in April. It got even more incredible in early May. Following a spring-tease May 1-3, a massive surge of May cold descended on New England. A storm on May 8^th and 9^th produced 5-10 inches of not wet snow but powder across much of the northern Vermont high country. I will remember May 9^th for as long as I can remember the dates of all my favorite weather events. Sub-zero wind chills, temperatures in the 30’s all day, snow squalls and several inches of snow on the ground throughout the day. It was truly surreal! Then, in a total about face, a heat wave hit Vermont in a span of less than 3 weeks. Most official reporting sites in Vermont hit 90 degrees oddly beating locations such as Philadelphia and Washington, DC that have yet to see 90 degrees this spring (a rarity)

In many ways 2020 has not been a year we would ever hope for. It certainly was not a memorable winter season from a weather standpoint either but will obviously be remembered for worse reasons years from now. The 5-weeks of winter that the Vermont high country saw in spring has brought some optimism and provided a reminder of what CAN BE. I can hope, like the rest of us, that we can come to a resolution as to an appropriate way to face the challenges on the ground and have a ski season we can all enjoy. Look forward to being back next winter to serve the MRV like always. Until then, stay engaged and continue to work the make our community a special one and the world a better place both now and in the future.

April rollercoaster begins with elevation snowstorm that came close becoming historic for the season

The last regular update of the winter season includes a classic roller coaster ride of April weather in Vermont. A bit of everything as they say with big swings in temperature and a variety of precipitation types which at times could be falling pretty hard atop both the Vermont high country and the low lying valleys.

I haven't updated in several days but our late week storm that was teased as a potential snow producer is poised to deliver some of those goods. The storm has the capability of becoming that elusive April 2-footer but will fall short of that status but not by much. The chess pieces are well positioned with a nice block in the jet stream over the Northwest Passages (small body of water NE of Hudson Bay) and a closed low  in the jet stream over the Canadian Maritimes often referred to as the 50-50 low. A very strong jet stream impulse will attempt to plunge into this set up and is poised to become a big New England precipitation and snow producer. The maturation of this storm is close to perfection for northern New England as a whole but will belly flop just enough so that the heaviest snow is confined to areas north and east of Vermont (northern Maine mostly). Still, Vermont, especially the high country of Vermont will get several inches of snow.

Precipitation will be mostly rain as it commences Thursday morning but areas above 2500 feet could see a period of heavy wet snow with any intense areas of precipitation. The chances for this should actually increase as the day progresses and the threshold elevation for snow will also drop as we move into the afternoon and evening. The axis of low pressure will pass directly over the state of Vermont and continue to strengthen while pushing east. Much of the state will attain access to the colder conveyor of moisture Thursday evening into early Friday and this means snow pretty much everywhere, even in the low lying valleys. Accumulations by midday Friday could be as much as 10 inches above 2500 feet but will likely be confined to a few gloppy inches or less below 1500 feet (which is where most of us live).  Snow consistency will also be very sensitive to elevation with the possibility of a few powdery inches across the high country as temperatures drop into the 20's early Friday. In low lying areas temperatures are likely to hover near or above the freezing mark Thursday night and much of Friday. This storm reminds me a bit of our late February storm, an event where we overperformed and saw over 15 inches. We are dealing with late season challenges that will make that event difficult to replicate but it would have been a nice way to close out the season hypothetically speaking.

Conditions will be blustery through Friday into Saturday even as the snow tapers off. Temperatures are likely to top out only in the low 40's Saturday but Sunday should be a little tamer with calmer winds and readings up near 50. With a little help from some sunshine Sunday, we could actually do several degrees better than 50 but I am not so sure about such help right now.

It will get interesting early next week and worth watching but not because of snow. The big ridge over Alaska is working its magic and will result in an onslaught of cold and wintry weather across the front range late this weekend. The storm responsible is a big one and will gather a lot of Gulf of Mexico moisture as it travels north and east. A LOT of moisture capitalized. Both heavy rain and wind are possible on Monday across the northeast along with relatively mild though not excessively mild temperatures. In recent years we've had some big spring storms result in power outages and some minor flooding across the state and this appears to be a candidate for both though some changes are still possible. When the rain ends late Monday we could also see a one day surge of in temperatures into the 60's Tuesday. After that, some relative chill returns although the bulk of this will impact the central United States and this airmass will modify somewhat before reaching New England.

The pattern though through April 20th continues to look cold and capable of producing more winter weather. That said, regular blogging activities will come to an end with the next post consisting of a seasonal summary. If some interesting weather comes around, I'll certainly talk about it on twitter some, especially since I can't complain about Mets baseball right now.

Winter could be stirred up from the ashes in a potentially interesting setup late next week

Sunshine late on Tuesday and early on Wednesday was a nice needed break from the succession of cloudy days in northern Vermont. The clouds came back as of late Wednesday and unfortunately they will be with us through at least early Friday. In the short term, I wouldn't describe our upcoming weather as especially exciting or anything I would necessarily wish for but it is unique. There is a terrific weather enthusiast in southern Vermont (@vermonsterWx) who posted a atmospheric sounding, a method of looking at the vertical column of air at a specific location. That sounding illustrated a unique situation where in spite of a northwest wind at the surface, much of the air above us is getting warmer over time. This is happening thanks to a wound up storm system (the one that missed us) that is spinning ferociously offshore while occluding and pumping in some relative warmth from its northern flank. The warm air isn't the only thing being shoved in our direction from this storm, there's moisture that is also expected to impact much of northern New England and will do so via the back door. Most of Thursday will be cloudy and the radar will show rain and snow approaching Vermont from the northeast, the opposite of what we typically see when it comes to approaching weather in New England. This precipitation could fall as some snow for a period during the late afternoon but this will change to rain by nightfall as that aforementioned column of air continues to get warmer. The rain will be sporadic in nature but should continue in that fashion through early Friday.

I am sincerely hoping that we can optimize the stretch of weather between late Friday and Monday. It is all a question on the extent of cloudiness. We are expecting a weak area of high pressure to build over the state beginning late on Friday and an innocuous cold front on Sunday isn't likely to bring any significant rainfall to the state. It would certainly nice if that weak area of high pressure was strong enough to remove most of the clouds. If that were to happen we could see temperatures reach the high 50's Saturday and near 60 on Sunday. I'll hedge a little for now and just suggest some partial sunshine and low to mid 50's for the weekend with little wind.

The early part of next week looks like a continuation of the weather from the weekend. Some limited sunshine, a tolerable amount of wind and temperatures mostly in the 50's during the day. And then it gets interesting. I mean where was this pattern back in January !! The pattern that supported a bottling up of cold across Alaska has vanished and there's some evidence of a blocking ridge (depending on what set of ensembles you are inclined to believe), the EPO looks decidedly negative (relaxed Pacific pattern) and the AO appears neutralized. There are a few different scenarios that could play out given these circumstances but one way or another, a large section of the contiguous U.S. is likely to see a southward push of early spring cold weather. It will assuredly be temporary but it will not lack for excitement. The European operational and ensemble members (and to some degree the GFS ensemble member) showed northern New England taking the brunt of this with a phased storm system impacting us in the middle to later part of next week. It would be a rain to heavy snow scenario that would not be insignificant. Other simulations also indicate the ridging over Alaska but confine most of the excitement to areas out west. From a weather perspective this will be an interesting one to watch. At the very least, we are likely to see a volatile stretch of spring weather starting in the middle of next week that will likely include cold, possibly some snow, a few mild days followed perhaps by more cold.

It's probably worth one or two more blog posts at least.

Very typical early spring weather for the next week in northern VT but early April looks stormy

The snow this past Monday night was magnificent. One of those unique cases where northern Vermont performed exceptionally well in spite of a storm track well south of Long Island. The dry airmass was displaced rather easily allowing moisture to stream in off the Atlantic Ocean rather efficiently. Areas to our south that should have performed better under-performed or changed to rain while some areas across the northern half of Vermont received over a foot.


And with the midweek storm passing well to our south, sunshine made a multi-day appearance and allowed temperatures to climb well into the 40's Wednesday and close to 50 on Thursday and  Friday. The milder weather felt nice Thursday but it pales in comparison to what occurred in Oklahoma with temperatures reaching 90 and even 100 degrees in a few places. It has been a very warm winter across much of the south and an even warmer, at times summer-like month of March.


Just as we begin to see April on the immediate horizon, the pattern looks stormy and also capable of producing more snow. More on that in a bit. In the meantime, our weekend got split in half. The first half Saturday is sensational. Following a chilly near 20-degree start, a full day of sunshine should boost readings toward or above 50 and with very little wind. Sunday is a disaster with rain arriving by mid-morning and continuing well into the evening. The rain will hold temperatures near 40 but it won't be cold enough either at the surface or aloft to support snow during the day. At best, we could experience a bit of freezing rain in spots similar to what we saw back on March 13th. Temperatures aloft are expected to cool Sunday night and allow for some snow across much of the northern Vermont high country. This once powerful weather system over the upper Midwest will become occluded well before impacting Vermont, but with all occlusions, even the rainy ones, there's always a cool pool and that could provide a gloppy inch of snow to valley areas and a few inches above 2000 feet by Monday morning.

The aforementioned storm system will only slowly move away in the early part of the upcoming week. This will allow clouds to linger and likely keep temperatures from moving past the 50-degree mark. Current data suggests that this will improve as we get to Wednesday with a couple of mild days possible on April 1st and 2nd. This notion is predicated on another mid-week storm dodging interior New England much like this past Wednesday. A few days ago there were hints of a fairly big Vermont impact from this but not so much as of Friday March 27th. Worth watching this storm however for another possible change.

I'll never forget how insulted snow-lovers in Albany were in the winter of 2015-16. They got shut out of everything all winter and recorded most of their snow during the first week of April if I am not mistaken. Given their nearly 60 inch snow climatology, that was a snow hole for the ages. Northern Vermont actually put up a rather good fight this winter from a snowfall perspective but have been repeatedly plagued by an adverse set of teleconnection indices (AO/EPO) all winter. Much like that 2016 spring, our early April is looking rather stormy and quite volatile on the temperature scale. The AO appears to be as neutral as ever and the jet stream in the Pacific looks as relaxed as it's been all winter. I still think much of the most intense cold will remain bottled up near the Arctic given the lack of a strong high latitude blocking mechanism but the pattern does support the notion of some big east coast storms and at least a day or two of much below normal temperatures (In early April that's 30-35 for max temps).

In the 15 or so years doing the blog, the big 2-foot April snowstorm has somehow eluded us which I find somewhat remarkable in the context of that time span. No, I haven't published any research papers on it but I would imagine the return period for such an occurrence is more than once over a 10 year period (at least for the high country). Should we get something like that, would we consider it a slap in the face at this point ?