Historical Posts Archives - Page 22 of 378 - Mount Washington Observatory

April 2019

Happy Earth Day!

2019-04-22 10:07:30.000 – Chloe Boehm, Summit Intern

Today is Earth Day which means it is a great day to recognize the beautiful planet we live on and the vast number of species that inhabit the planet with us. Living and working on the top of Mount Washington gives us the unique opportunity to experience the extreme weather that this area sees as well see the incredible sights on a daily basis. Not many places in the world can you go from a day of sunny skies and light winds to recording a peak wind gust of 142 mph in less than a week. The snow has started to melt the last few days, allowing the colors of the rocks and sedge grass to poke through, quickly transforming our home from a wintry tundra to a more welcoming colorful place. Many of us have been taking the opportunity the past few days to explore this recently thawed environment, finding a seemingly infinite number of little rivers caused by the melting snow along with alpine flowers starting to pop up.

The theme of this year’s Earth Day is Protect Our Species. The White Mountains in particular are home to a very special type of butterfly called the White Mountain Fritillary. This butterfly can only be found in the alpine zone of the Presidential Range and changes in its habitat in the past several years has caused this species to be considered endangered. It takes a lot to survive in this particular environment so it is truly incredible that butterflies with wing spans of less than one-and-a-half inches can survive the fierce weather of Mount Washington.

White Mountain Fritillary. Photo courtesy of Vermont Center for Ecostudies.

The Appalachian Mountain Club has conducted projects to study these butterflies, trying to learn more about them and how to protect them and their habitat from future harm, and will likely continue such projects in the future. Since the alpine zone of the Presidentials is a relatively small area, we must do all we can to help protect the environment to make sure that these butterflies, that adapted to survive the extreme weather, still have a place to live. So next time you are out hiking or exploring the White Mountains, keep an eye out for these beautiful creatures and make sure you are doing your part to keep their habitat safe!

Chloe Boehm, Summit Intern

Signs of Spring

2019-04-19 15:30:09.000 – Thomas Padham, Weather Observer/Education Specialist

Photos taken by Weather Observer Ryan Knapp of the progression of our melting snow pack ahead of the weekend rain.

Signs of spring are finally working their way into the surrounding valleys here of northern New England, with most of our snow melted here in the North Conway area. Spring birds have been here for the last few weeks, and we even had a few sightings here on the summit of Mount Washington! With rain currently falling as of this writing and temperatures in the 40s, it makes us wonder: are we done with the snow here on the summit?

Yellow-Bellied Sapsucker photographed on the summit by intern Chloe Boehm April 8th, 2019

Although snow can fall any month of the year on the mountain (and it has over 1” even in June-August) we typically do not see any snow from very early June through the middle of September. Some years this season can be far longer, and taking a look at the longer range models there isn’t much in the way of snow on the horizon. Things could certainly change in May (I’ve witnessed nearly 3 feet of snow from a storm Mother’s Day 2017) so we’ll absolutely keep our Eastern Mountain Sports winter gear handy!

This weekend’s rain and warmth will likely leave the immediate summit with just patches of snow and ice leftover. Due to our high winds this isn’t too out of the ordinary, most of our snowfall settles lower down on sheltered portions of the mountain. In the Great Gulf and Tuckerman Ravine in particular there is still plenty of snow, and this will remain the case through at least early June unless we see a very rainy and warm May.

Our next chance for at least some wintry precipitation will be Wednesday-Thursday next week, although details are likely to change in the coming days. Image courtesy of Tropical Tidbits.

In the shorter term, after the weekend rain and warmth another system tracks across the area Tuesday through Thursday, with temperatures likely falling just below freezing and at least some mixed precipitation. Snow totals will be pretty meager due borderline temperatures and also the thermal profile favoring sleet or freezing rain over snow at this time. Sometime the following weekend, April 27^th-28^th there is also the potential for some snow above roughly 4,000 feet. At this point we’re really getting ahead of ourselves though. The big picture message is there doesn’t appear to be any more major winter-like storms on the horizon through the end of the month, and what snow we do see here on the summit likely won’t substantially add or rebuild our summit snow pack. April looks to be our first real spring-like month for the mountains of New England!

Thomas Padham, Weather Observer/Education Specialist

New Personal Wind Record!

2019-04-16 20:14:03.000 – Ian Bailey, Weather Observer/Education Specialist

We had a pretty exciting night here on the summit last night! Most of us set new personal wind records, with a maximum verified gust of 142 mph! It was a long night of deicing and monitoring the Hays Chart, and we did not expect it to get anywhere near as fast as it did!

Looking back on what lead up to the event, I can’t help but laugh. As a crew, we were sitting around the dinner table last night commenting on how fast we thought the maximum gust was going to be. Our volunteer John Donovan set the rules for the “wager”, and was the first to call out a speed of 108 mph. The rest of us put out numbers like 111, 117 and 118. I recall feeling pretty confident in my bet, having just forecasted for the evening not but an hour before. I could see the ingredients coming together for a 110-120 mph event, but clearly couldn’t piece together that it would be much more intense.

So what was I seeing in the forecast? It was a combination of 3 main things. First was the big chonker of a low pressure in our proximity, as shown below:

With the cold front having passed through the Whites already, and with the region situated in the Southwest quadrant of the low, elevated wind speeds were to be expected in general. Usually some of your faster wind speeds come around the backside of the system, and quick moving cold fronts generally help make that the case. Additionally, there was a pretty tight pressure gradient looming over us, between the low and a region of high pressure to the Southwest. So with Northwest winds ripping around the back side of a strong low pressure system through a tight pressure gradient, right off the bat I knew winds across the summit were going to be higher than average.

Then, when I went to look at the upper atmosphere, the models indicated what we call a “vorticity bullseye”, or a region of elevated vorticity, directly overhead. Vorticity is a fancy term for rotation in the upper atmosphere, which can lead to instability and turbulence that translates down to the surface. So not only was there fast horizontal movement, there was movement through an unstable atmosphere as well.

Finally, when I checked out a sounding for the region around the low, I saw the definitive proof for high winds. The red and green lines on this chart indicate a temperature profile and dew point profile respectively. As the lines move to the right of the chart, they are indicating warmer temperatures. And as they move to the left, they indicate colder temperatures. Now, generally speaking, temperature decreases with height. When the opposite is true, and temperatures are increasing with height, that is known as an inversion.

Inversions, which are great “stable” layers in the atmosphere, act like a lid for air movement below it. It takes a lot of force and lifting to break through that lid, and usually the inversion instead acts as a sort of compression down on the air underneath it. We are no strangers to the effects of compression here on Mt. Washington, and we know these capping lids force an acceleration in the winds that move across the top of the mountain. As you can see in the image above, we had a pretty sizable inversion sitting right at the level of the atmosphere where the summit resides. So, we were situated in the quadrant of the low with the fastest moving air, underneath and unstable environment, with a strong inversion right above us. With these 3 ingredients combined, I knew it was going to be a 100+ mph night.

But apparently I underestimated how much of a true impact this atmospheric setup would have, because as we now know, the winds were way higher than what we expected!

Unfortunately, I was downstairs asleep for the first half of the insanity. But the rest of my crew decided to forgo sleep to witness the craziness! John stayed up late, monitoring the first half of the night as the Hays Chart climbed higher and higher. He definitely set a new peak wind speed, and was very excited to have been up for it!

Jay and Adam, while both very excited about the crazy winds, were working their tails off to keep the instruments and ice under control. Along with the winds, the summit was experiencing some incredibly intense icing as well. According to them, they would clear the parapet of ice, come back downstairs, and then turn around to go back at it 10 minutes later. Adam noted that the ice was accruing as fast as 10-12 inches per hour! That’s bonkers…

All night long they battled the crazy ice. And when the peak 142 came in at 4:15 am, they was much, albeit exhausted, rejoicing! Even once I was awake at 6, winds were still gusting to 140 mph and the icing was really bad! So don’t worry, I got to join in on the fun too! The crazy speeds didn’t really slow down until later in the morning, and by slow down I mean only gusting to 110 mph. As you can see by the most recent look at the current Hays chart, we’ve been gusting over 100 all day! And as we talked about at dinner tonight, it was a welcome change from the relatively calm shifts we’ve had for the last month or so. Overall, it has been a very exciting day!

Ian Bailey, Weather Observer/Education Specialist

Intern to Night Observer!

2019-04-15 06:50:58.000 – Jay Broccolo, Weather Observer/Meteorologist

It has been a bit since my last blog post, but for good reason. I have been training and becoming accustomed to the night shift. I recently hired as the Night Observer and Meteorologist and there is not a whole lot of overlap going from Intern during the day to Night Observer. The only similarity is the forecast, which I am thankful for the time spent as an intern so I could familiarize myself with the microclimate of Mount Washington and its orographic effect on the weather. The rest has all been new experiences.

I am sure many of you have read past posts by night observers going through their night and experiences, but I would think that everyone’s experience is quite different. I have worked plenty of nights as a geologist and logger on ultra-deep drill ships in the Gulf of Mexico. They were 12-hour shifts that often turned into 14-16 hour shifts for 3 to 4 weeks at a time and sometimes stretched to 5 weeks. It was certainly quite the experience to say the least. There are a few differences between the two though. One difference is that on the oil rig, I had several others working alongside me whereas here at the observatory, I am alone. Marty occasionally comes up to the weather room to eat out of one of his three food bowls around the building. He is actually sitting in my lap as I write this. I quite enjoy having all this time to do my work, observe and forecast the weather and contemplate many a things. It gives me an opportunity to research, learn new skills, and listen to plenty of music when I have some downtime in between tasks. Actually, thinking about it, there are quite a few differences. My heart is thanking me simply because the stress level here at the observatory is far less than the rigs and I absolutely love what I am doing here. Do not get me wrong, the rigs were a fantastic experience; I was a part of some extreme engineering feats and learned quite a bit, amongst so much more. Having said that, I studied Geology to learn how the Earth and its systems work, not to drill for oil.

So now, I am here with my dream job where I have fun and look forward to each shift. I am fortunate enough to experience every sunrise and sunset that is not obstructed by some weather phenomena and I get to experience weather that most people sleep through. I would be lying though if I said there were not some creepy aspects as well. My eyes and ears play some tricks on me, which some of them have been propagated by my shift mates. Everything makes strange noises up here: the wind, the building, even the electricity. Everyone has ‘seen’ weird things out of the corner of their eyes in the dark. Well up here is no different. Obviously, there are explanations for them all, but it is still eerie. I suppose it keeps things exciting. As if the weather isn’t enough for that, right?!

Speaking of the weather, the forecast is my favorite part of the night. I love diving into all the resources we have, the ones I have taken with me from Leeds, and some of the forecasters at the ECMWF. There are so many resources at our fingertips. Most are free and open to the public with a couple paid services that I or we use. I still find new resources to use to backup or introduce new techniques and am very proud of the end product after all the time and effort spent coalescing all of the data. Then, the following night I spend some time verifying my forecast. If an aspect was off, I figure out why and apply to it future forecasts.

Lastly, because the night observer works alone, all the work completed is my own. I take pride in the small details and tasks throughout the night. Even changing the charts and making sure that the records are exactly how they should be so that future researchers can access our data and say “wow, what great records.” I know, a bit over the top, but It is the small things that keep us going on a daily basis.

Jay Broccolo, Weather Observer/Meteorologist

85th Big Wind Anniversary

2019-04-08 10:25:42.000 – Staff, MWO

The founding staff of the Mount Washington Observatory in 1932: (L-R) Alex McKenzie, Bob Monahan, Joe Dodge, and Sal Pagliuca.

Nearly 85 years ago, on the tallest peak in the northeast, a group of hardy individuals witnessed a truly unforgettable event, a storm which brought a world-record 231 mph gust of wind to the summit of Mount Washington. It was an incredible event, and a test of both observer mettle as well as equipment on the rime-shrouded peak. The event hit home the importance of maintaining a manned weather station here, continuously sampling the environment and creating a long-standing data record for increased scientific discovery.

Our world famous winds still rage to this day! Pictured is our Hays wind chart from February 25th, 2019 with a peak gust of 171 mph.

Now, 85 years later, we are humbled and excited to host a commemorative celebration, honoring the steadfastness of early observers, and the incredible measurement they captured. Please join us this Friday, April 12^th, as we celebrate this incredible event! Admission to our Weather Discovery Center museum will be free, from 10 am – 3 pm. Additionally, there will be two “Live from the Rockpile” connections to observers on the summit, in addition to a special presentation at 12 noon, featuring the details of that incredible 231 mph storm. Light refreshments will be available as well. We hope to see you there!

Staff, MWO

Still Winter In Our “Backyard”

2019-04-08 05:49:55.000 – Ryan Knapp, Weather Observer/Staff Meteorologist

The acronym “NIMBY” (Not In My BackYard) is typically used for a person that objects to something perceived as unpleasant/dangerous in their local area. However, growing up around Lake Tahoe (CA) I always heard this acronym used to describe the mentality behind the sudden spring slow-down in businesses associated with winter activities like ski resorts, snowmobiling, lodging, restaurants, etc. It didn’t matter if we had enough snow to last us well into June or July, when the Central Valley and Bay Area (where a lot of tourists came from) started to warm up, for folks in these areas, winter activities were no longer on their minds as winter was not in their backyard. As a result, the winter activities in my backyard would start to slow or close up shop for the season. And tourists that came to visit would always stick out as they would be wearing less than ideal clothing/gear for the conditions they were in. On the flipside, my backyard would have so much snow at times that it was jarring when visiting areas outside my bubble and see the sights/sounds/smells of spring were in full swing. And sometimes that would mean sticking out like a sore thumb as I was overdressed and appear pale in comparison to those that had had a jump on spring far earlier than me.

Flash forward to now and it is a similar set up here. Looking out at my backyard at home as well as here on the summit, winter is far from over at this point in time. Inches of snow covering my homes backyard builds to feet of snow still covering the mountain sides around me. New England’s “fifth” season, mud season, has not quite broke out here yet. However, all I have to do is look around my social media feed to know that spring is moving forward without me in southern New England and points south as I see pictures of flowers springing up and my friends all starting to do spring-like activities. And around here, I am seeing traffic starting to thin as folks from these areas slow their travels north as winter is no longer in their backyard.

wintry view of Boott Spur and the southern Presidential Range on April seventh 2019

Backyard view of Boot Spur and the southern Presidentials taken 7 April 2017

Eventually spring will move into these parts and winter will all be but a fading memory as things melt out. However, that moment has not happened yet, and will not happen for the coming days as more storms with wintry weather head this way. If you live in areas where winter is NIMBY but you still want to do winter activities, there are still plenty of offerings the further north you head. However, that means you need to be prepared for the winter weather you might encounter. Pack layers so you can add/remove articles as changing conditions occur. Pack traction – lower elevation trails might need microspikes in areas while several trails above treeline still need crampons/ice axe especially as freeze/thaw cycles result in even more icy conditions. The added traction will also allow to stay on the trails to avoid erosion or damaging the flora next to heavily trafficked areas. Pack goggles, balaclava, gloves, and other winter gear. You might luck out and get a day/summit where they are not needed, but if on the other hand you get weather deteriorating on you, they are important to have. Pack the ten essentials (although, that is true of any season) and all other necessary gear. And continue to keep an eye on the weather forecast and backcountry conditions in the days leading up to your excursion.

Ryan Knapp, Weather Observer/Staff Meteorologist

The Culprit Behind This Wintry Weather

2019-04-07 12:53:02.000 – Chloe Boehm, Summit Intern

Even though meteorological spring has sprung, the summit has seen its fair share of wintry weather recently with more on its way. Many of the recent precipitation events have not been organized low pressure systems but due to upper level disturbances in the atmosphere. Since this terminology has been common in our forecasts recently, I thought I would take the opportunity to explain a little bit more what it means.

When meteorologists talk about the upper levels of the atmosphere, they are usually discussing elevations with a pressure of 500mb or less, usually above 18,000 feet. Looking at the flow patterns in the upper atmosphere can give forecasters a good sense of the general pattern of upcoming weather as well a reason why areas may be getting precipitation without an organized system. There are two distinct features to look for when looking at upper level flow patterns, ridges and troughs.

Photo courtesy of WeatherOps

As you can see in the picture above, troughs are roughly U shaped while ridges look like an upside down U. Clouds and precipitation is usually associated with troughs while fair weather is associated with ridges. Simply put, this is due to the movement of air in the ridges and troughs. In a trough, air is rising; as this air is rising it cools and condenses, creating clouds and precipitation. On the other hand, ridges are found where air is sinking which brings warmer and drier weather.

The flow in the upper atmosphere is comprised of a series of ridges and troughs, creating a wavy pattern. These large ridges and troughs span over 3,700 miles and move very slowly resulting in long persistent weather patterns. Embedded within these large troughs and ridges, however, are upper level disturbances, also known as short waves or vorticity maximums. These are waves with a length of less than 3,700 miles and move much faster and through the longer waves. This causes the larger ridges and troughs to distort briefly as the short waves pass through them. Below is an example of a 500mb chart showing both long wave troughs as well as short wave troughs. The red dashed lines indicate the long wave troughs and the blue dashed lines indicate the short wave troughs. The green areas indicate areas of precipitation.

Photo courtesy of NWS

As you can see by the chart, short waves or upper level disturbances are a chief culprit in episodes of precipitation. They can interrupt a long pattern of dry weather with a quick but potentially heavy episode of rain or snow. This is what has been happening this past week and what will continue during the upcoming week. There is a conveyer belt of short wave troughs that are headed towards us, bringing short stints of precipitation with high pressure trying to build in between. Below is an image of a 250mb map for last Friday afternoon. The red arrow points out a short wave trough that brought the band of precipitation throughout New England Friday night.

Photo courtesy of Tropical Tidbits

Although temperatures are warming and the snow is starting to melt, wintry weather is not quite over especially on higher terrain.

Chloe Boehm, Summit Intern

Wind Statistics From Winter 2018-2019

2019-04-05 15:49:02.000 – Thomas Padham, Weather Observer/Education Specialist

It’s been a very memorable winter season, something I’ve mentioned before in past blogs but still can’t really get over is how windy it’s been! I decided to do a little more digging into just how windy this winter of 2018-2019 has been, and also how it stacks up to our all-time records going back to the 1930s. The cherry on top to this winter season has obviously been a new February record wind of 171 mph, but I’ll focus more on the frequency of high wind events here on the summit this past year/winter.

Hays Chart from February 25th, 2019 with a peak gust of 171 mph

November to April is typically the windiest part of the year for the summit of Mount Washington, when we see 100+ mph winds every 4-5 days on average (roughly 32 days per season). This extended winter season has been very impressive, with 43 days of 100 mph winds or greater, and we’re only just starting the month of April so there’s still time to add a few more to the list!

Besides the extreme events, the consistency of the wind has also been remarkable. From the period November 2018 to March 31^st2019, the summit averaged winds of 47 mph. This is a full 4 mph higher than 30-year norms, impressive for a full 5-month period as we often see one month a few mph above followed by a month below, which often cancels things out. February was anomalously high as expected given it featured two extreme wind events (148 mph and 171 mph). The month averaged 55 mph, 11 mph above climate norms! This rates February as our third windiest on record, with 1939 taking the top spot with an incredible monthly average wind of 70 mph.

All of this wind personally has meant a lot of de-icing and challenges for our crew on top of the mountain. My crew of Taylor, Ryan, Chloe and I have become very accustomed to 100 mph winds this winter, with at least one day of 100+ mph winds occurring each shift on the summit continuously since October 17^th! This is the longest stretch of such high winds for all of our current observers, including Ryan who has worked on the summit for 13 years now.

Thomas Padham, Weather Observer/Education Specialist

Yay Spring…Just Kidding! April Fools!

2019-04-01 12:24:18.000 – Ian Bailey, Weather Observer/Education Specialist

Of course, shenanigans were bound to occur this shift with today being April Fools Day. However, while pranking each other is all in good fun, being pranked by the weather certainly hasn’t been.

Our shift started very spring-like indeed. On shift change day, we came up to a summit that had been sitting under clear sky conditions for over 20 hours! Temperatures were on the rise, and we actually had wind chills that weren’t below freezing! Our crew was settling into the idea of transitioning out of Winter conditions, especially once the temperatures crested to the freezing mark towards the end of the week.

WPC Surface Map from Friday morning showing the stationary front.

To start the weekend, a cold air boundary pushed its way into the Northeast. So we initially were wary that there may be a significant temperature drop and we’d be right back into winter. Interestingly enough, that boundary stalled out into a stationary front, basically right over top of us! Stationary fronts get their name from their lack of progression, and how they can linger over a region for several days at a time. Additionally, they are a fairly week boundary between cold and warm air, and generally don’t produce much in the way of a wind change or elevated wind speeds. As you can see in the surface map above, there was also a high pressure system anchored in the Southeast region of the U.S. during that time that was responsible for rotating warm, moist air up from the Gulf of Mexico.

WPC Surface Map from Saturday afternoon showing the low pressure system.

So while we lost our clear skies above to high clouds and inevitably fog, we really didn’t see much of a temperature drop. We did have some light snow showers, but it was nothing like what we normally see during our 8 month Winter season. Then, on Saturday, a low pressure system pushed in from the Great Lakes Region, and actually merged with the stationary front creating a new, stronger low! With a well-defined warm front that lifted through New England over the course of the day, our temperatures shot above freezing and made a run for the 40-degree mark! With this, we were expecting a transition through a wintery mix of precipitation throughout the day. But because of how fast temperatures rose once we were inside the warm sector of the low, we skipped right over sleet and went straight to freezing rain and rain! As you might imagine, we had some pretty serious melting here on the summit, and lots of glaze ice initially!

As the low continued to push Northeast through Sunday, we could see that we were about to get our big April Fools from Mother Nature. While we had grown accustomed to the idea of “Spring” since we arrived on Wednesday, we could see that the incoming cold front associated with the low was going to be a doozy! We had rain on the summit all the way into the mid-afternoon, with plenty of ponding and water build up on the summit. And once that cold front passed, temperatures plummeted!

Our instrument display showing the rapid drop in temperatures following the cold front.

We dropped almost 10 degrees over a period of 2 hours, which definitely sent us back below the freezing mark. There wasn’t even a noticeable transition through the typical wintery mix of precipitation. We went from rain showers to snow showers (snaps finger) like that. And things were flash-freezing all across the summit cone. When I went to the top of the tower to de-ice the instrument ring, it was like trying to walk on an ice rink (which was a very similar case down in the parking lot on the way to the precip can). So in what felt like an instant, our aspirations for Spring-like conditions were, literally, blown away and Mother Nature gave us a brand new round of Winter headed into April.

Back to Rime Ice here on the summit!

As you might have guessed there have been plenty of April Fool’s shenanigans last night and today. But none of them could compare to the Wintery trick played on us by Mother Nature. Oh well! Happy April Fools everyone! Back to de-icing!

Ian Bailey, Weather Observer/Education Specialist

Looking like spring?

2019-03-29 12:16:48.000 – Adam Gill, Weather Observer/IT Specialist

So far this spring it has been a cold one across the higher summits and much of New England. This has largely been due to a big ridge over Alaska that has been pushing the cold air in the arctic down into the eastern half of the continental US. We have only had one large melt out this season so far and temperatures did not even get much above freezing. Now that we are getting close to the end of the month, it is looking like we will be about 4 degrees below average. With the warm weather expected for the last few days of March we may raise average up to about 3 degrees below average. For precipitation, we are currently sitting at about 3.30 inches of liquid water, which is well below our March average of 7.67 and with not much precipitation expected, this will remain well below average. Snowfall has actually been just about average. Without many rain events and many of the snow storms that we got were cold so the snow to liquid rations were low. We are sitting at 42.9 inches and the average is about 45 inches.

Now that we are starting to see warmer weather, will it be sticking around? In the short term, we will be getting back into a cooler weather pattern with the possibility of more snow mid-week next week. Beyond that, it is starting to look like warmer weather will be making a much stronger appearance. Since it is a ways out, I will be taking a look at some of the indicators that show a warmer weather pattern rather than looking at what the specific weather would be.

In the near term, looking at next week, the ridge in Alaska is holding strong with cold air over New England. Below is the 500 mb (millibar) height anomalies for next Monday, April 1^st. The warmer colors indicate chances of above normal temperatures at the surface and the cooler colors indicate below average temperatures at the surface. There are two anomalously high heights over Alaska and in the North Pacific, with lower heights over New England and this pattern is conducive to the formation of Nor’easters. Many models are showing a Nor’easter forming during this time frame but the track of the low is still very uncertain.

500 mb height map for Monday April 1st. Indicates height anomalies at the 500 mb level. Large ridge over Alaska shows where the warm air is and the cold air is being displaced downstream into the eastern half of the United States.

Below are the model runs of the European and then the United State’s GFS model. They both have a storm but the location is vastly different.

Location that the European model indicates for the center of the low pressure system on Wednesday April 3rd. This is just one run and there is still a lot of uncertainty for the exact path of this storm

Location that the Global Forecast System (GFS) model indicates for the center of the low pressure system on Wednesday April 3rd. This is just one run and there is still a lot of uncertainty for the exact path of this storm

This will have to be a storm to watch. There is cold air just north of the boarder that could be pulled into the backside of the storm, leading to snow all the way to valley floors. At the elevation of the summit here though, we will be cold enough for snow even if the cold air does not slide south. As that storm moves up into the Canadian Maritimes, cold air will move into New England before warm air starts to return.

This is when more consistent warm air is expected. The first indicator is the Jet stream over the pacific will become stronger and more zonal, aimed in a west to east orientation aimed at the west coast. This pattern aids in the development of low pressure systems downwind of the Rocky Mountains in the central plains. Due to the counter clockwise rotation of low pressure system, that sets up for a more southerly low level atmospheric flow over New England. Now that we are headed into April, the sun is strong and most locations south and west of us do not have much snow cover. This will allow for the sun to heat the lower atmosphere more efficiently rather than the suns energy going into melting the snow.

Below is the forecasted 300 mb (about 36,000 feet above the surface) wind map for Friday April 5^th and you can see the strong jet of air just off the west coast that extends into the central Pacific.

The strength in knots of the Jet stream. Usually strong jet max’s aimed at the west coast with the energy stretching into the central pacific results in a warmer then average temperatures in the eastern US

The ridge over Alaska finally starts to break down and with the jet stream further south in the Pacific will allow for warmer air to move north out ahead of it in the eastern US. Below is the 500 mb map for April 5^th, the warmer colors are starting to settle over New England with the lower heights well off to the north.

What the 500 mb height anomalies look like on April 5th. Good indication of warming on the east coast

This pattern is expected to continue into mid-April with above average temperatures expected. It will be a nice change of pace to start to see some more spring like conditions for a little while. Many areas in the valley will see quite a bit of their snow melt during this time. Once all the snow melts, the sun will do a better job of warming up the surface in New England with more frequent 50 and 60 degree days in the White Mountain Region soon!

Adam Gill, Weather Observer/IT Specialist

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