Historical Posts Archives - Page 16 of 378 - Mount Washington Observatory

Flux Tower Project III

2019-09-29 15:47:12.000 – Ben Charles, Summit Intern

Hello everyone, after an amazing experience being an intern here for the summer I am lucky enough to say I am staying for the fall internship. This summer I did a lot from forecasting, giving tours, and doing research.

My previous research project that I did this summer with intern Austin Patrick was called the Flux Tower Project. This consisted of comparing the accuracy and precision of handheld Kestrel instruments to the instruments on the Mount Washington Observatory deck and tower. Focusing on the variables of temperature, humidity, and wind speed. It was found that the kestrels had some strengths when measuring Temperature and high humidity events and a weakness recording all wind speeds and low humidity events.

The research I will be performing this fall will be a continuation of the Flux Tower Project from the summer. Since there was variability in the kestrels and they weren’t considered as accurate as the instruments on the Mount Washington Observatory deck kestrels will not be used this fall. The focus this fall will be to determine the thermal and moisture flux between the instruments on the Observatory Deck at the base of the tower, and the instruments on top of the Observatory tower.

The null hypothesis is that the spatial variability of measured air and dew point temperatures on the Mount Washington Observatory deck and tower do not impact the resulting computations of thermal and moisture fluxes. If the hypothesis proves true then there is little variation in the Bowen ratio and little to no thermal and moisture flux at such a distance. If false then there is large variation in the Bowen ratio and large thermal and moisture fluxes from the top of the tower and the observation deck, opening paths for further research. The Bowen ratio is an equation that allows us to explore the latent and sensible heat fluxes. I will begin this fall by gathering data calculating the ratio and producing plots to get a good visual sense of our results.

Ben Charles, Summit Intern

Western Snow and a Look Ahead

2019-09-27 19:16:02.000 – Adam Gill, Weather Observer/IT Specialist

Watching the weather over the past few days and watching a snow storm of epic proportions forming in the front range of Montana. A large low pressure system will be forming in the lee of the Rocky Mountains will create several days of easterly flow in Montana, leading to heavy upslope snow in the Glacier National Park area. Below is an image from the National Weather Service in Great Falls MT, in regards to what they think the expected snowfall is. As a person who loves snow, I am very jealous of them. I cannot wait for the first snowflakes to start flying here.

Snow fall predicted in Montana from the National Weather Service in Great Falls Montana

This is an incredibly impressive early season storm for the Front Range though given the set up and the cold air in place I am not surprised. There is a strong easterly wind with deep moisture, so once that impacts the mountain range, the mountains will ring out the moisture as snow. If you are on the downward side of the mountain range, the warming and drying of the air as it goes down the mountain will lead to very little snow fall. Many valleys in Idaho and western Montana are expected to see very little snow out of this event due to down sloping. This is a cool set up since we experience upslope snow all the time in winter and can end up being a significant part of our annual snowfall.

A graphic created about upslope snow in the White Mountains created by the National Weather Service office in Gray Maine

This also brings up an interesting misconception about measuring and predicting snowfall. Seeing 30-50 inches of snow in the forecast, many people imagine that at the end of the snow storm, there would be 30-50 inches of snow on the ground. This is very tough to attain, especially these high amounts early in the season. Snow is measured on a snow board every 6 hours in many locations so if you are getting 1 inch of snow per hour, you should receive about 6 inches on your snow board. That is cleared then put back on top of the snow for the next 6 hour period. In this period, the snow is still falling at 1 inch an hour so you measure another 6 inches of snow. The storm total is now up to 12 inches but when the total snow depth on the ground is measured, you have 9 inches. The reason for this would be compression of the snow. The weight of the new snow will be compressing the snow underneath it and result in a lower total snow depth.

For these early season snow, you have a warm ground as well as very wet heavy snow that will lead to both melting and quite a bit of compression so total snow depth after the snow storm is over will likely be less then what is forecasted. This happens a lot here on the east coast with Nor’Easters. Ahead of the Nor’Easter, we may receive cold, fluffy snow and as the low moves up the east coast, warmer more humid air will change the snow to a wetter, heavier type. This then compresses all the fluffy snow that initially fell resulting in less snow on the ground. Though snow storm totals from the snow board measurements every 6 hours may be quite close to what was forecasted.

With snow falling in Montana, the question becomes when is it going to snow here? I wish I had better news for all you snow lovers out there because it does not look to occur any time in the next week or so. The storm system in Montana will bring more warm air into the eastern US while the storm itself heads up into the Hudson Bay area. We do have a few cold snaps with temperatures getting below freezing but the atmosphere is very dry so the odds of getting snow is pretty low. If we do end up getting any snow squeezed out of the systems, it will probably just be some flurries at most and not lead to any accumulation. Below is a plot of all the different European models and not too many have any accumulating snow which is never a great sign. Especially going out 15 days.

This is the 15 day outlook for Mount Washington’s location from the European Model. Not too many of the ensembles actually predict there being much accumulating snow

This is the GEFS which is an ensemble of the American models going out 10 days and a few have a couple of inches. The mean at the bottom still rounds to zero so confidence is very low.

This is the 10 day outlook from the GEFS models that is from the American Model GFS. This model tends to have a high biased in snowfall especially in the log term so those ensembles forecasting 3 and 4 inches of snow are likely overdoing that amount even. Slim chances for snow.

Now of course at this time of year, especially with tropical systems in the Atlantic, we could see a sudden change in the forecast and result in a better chance of snow in the coming weeks and that is what I am hoping for. Right now all the models are in good agreement of cold, moisture starved air masses moving through but hopefully there will be a change in the weather pattern for the second half of October. That is too far out currently to have any idea of what is going to happen.

Adam Gill, Weather Observer/IT Specialist

A Taste of All Seasons

2019-09-24 10:07:54.000 – Laura Kee, Summit Intern

Hello everyone, my name is Laura and I’m the new fall intern up here on the summit! I am very excited to be able to live and work at the Home of the World’s Worst Weather, which has been a dream of mine for quite some time. Earlier this year, I graduated from Cornell with a degree in Atmospheric Science and a minor in Climate Change. I grew up outside of Boston which has helped fuel my love of all things meteorological, given the wide range of weather New England often receives.

The timing of my first week up here coincided nicely with an unusual stretch of sunny skies, calm winds and mild temperatures (in the upper 50s!). The clear conditions provided a great way to familiarize myself with the surrounding landmarks that are visible from the summit. On my second day here, I was amazed to be able to see the ocean from the summit, which is about 70 miles away! I found that it’s often easier to see it in the morning due to the sunlight reflecting off of the thin strip of water near the horizon. Valley fog is often visible after sunrise from the summit, and when it’s clear up here, the picturesque view makes it seem as though the surrounding mountain peaks are jutting out from a sea of clouds.

I have already been learning a lot during my first few days on the summit about the daily Observatory operations. In addition, I started working at the summit museum and it’s been great to get to interact with visitors who come to Mount Washington from all over the world. Diving right into forecasting has been really awesome, and it’s wonderful to be able to learn from the observers who have a lot of experience with mountain meteorology.

The views from the summit have been incredible and between daily tasks, I often find myself venturing outside to soak up the (somewhat rare) sunny and mild days up here because I know it will get much colder before too long. On Monday morning, I was very excited to be outside in sustained 65 mph winds for the first time! It was amazing to watch the clouds race by as they surrounded the summit. Every so often, the conditions would clear just enough for me to see the remnants of sunrise and patches of blue sky before getting completely enveloped in fog again.

I’ve heard that the fall is an awesome time to be up here because you truly get to experience the whole range in weather as the seasons change, and I’m looking forward to this new adventure up here on the summit of Mt. Washington!

Laura Kee, Summit Intern

Information For Autumn

2019-09-23 05:30:06.000 – Ryan Knapp, Weather Observer/Staff Meteorologist

Autumn has arrived and like usual, we have been receiving inquiries about foliage and the operating hours of the summit. I thought I’d take a minute to address these two items so you might be better informed for the days and weeks ahead.

When will we see peak foliage? To be honest, your guess is as good as ours as there is no set day/week and things can vary from location to location and from year to year. A great example of this is a post that NWS, Caribou does each year on or around October 2nd. The series of images are from a camera at Hanson Lake by the Presque Isle airport and shows the amount of change that has occurred on the same date at the same location over six years.

As you can see, things can vary greatly from one year to the next. One reason for the variation is weather as it factors into the colors you will see and when you will see them. A late spring or an overly wet summer can delay when color starts to show. If summer is on schedule though, adequate rainfall is important as this keeps trees healthy and aids in their leaf retention. Whereas a drought period in the summer can cause stresses that result in trees losing their leaves or change their colors early. As we head into fall, the best conditions to hope for are cool, dry, and sunny conditions. The sunny skies promote sugars in the leaves. Then the cool air, especially during the night time hours, allows the veins in the leaves to constrict and the sugars become trapped in the leaves promoting the formation of red, purple, and crimson pigments. While cool weather is good for autumn colors, freezing conditions are bad as frost and/or freezing conditions can result in the color change to be halted and/or result in a premature end to the season as leaves turn brown and start to fall. Wind and rain can also result in a premature end to the season as both of these can result in the leaves getting knocked off prior to fully developing their colors. And while warm days might make leaf peeping more enjoyable for people, warm days can actually reduce the intensity of the colors. So when it comes to weather, a lot of factors have to come together and depending on how and when those factors come together, it’s partly why colors and peak occurrence dates can vary from year to year. (If interested in learning even more about the science behind autumn foliage color, Harvard Forest is a great resource to get you started in your exploration)

Fall colors typically start in the north and high elevations in early to mid-September then gradually spreads southward through late Sept/Oct like a slow moving wave of sorts. The transition for the far north (think Pittsburg, NH) is already underway with several areas starting to approach peak color (at least from the pictures and reports I have seen). On the Presidential Range (where Mt Washington is located), colors are peaking at the 4000+ foot level (ie, treeline) and are starting to descend into the valleys around the summit. In the coming days, colors will start to peak around the base of the mountain, and then the wave of color will pass and continue southward in the coming weeks. Northern areas will then see the foliage falling off and leading into the “gray period” or “stick season” between fall and first snow. So, while peak color will vary, if you miss peak color in one area of the state/region, check around as there will be plenty of other areas you can still go to and experience New Hampshire’s foliage season.

For additional information, some great resources to check out are:

https://newengland.com/category/seasons/fall/

https://www.visitwhitemountains.com/foliage-tracker

https://www.visitnh.gov/fall

Additionally, if you Google “NH foliage” or “New England foliage” there are several other resources available to further assist you. Social media outlets like Twitter and Instagram are another great resource as you can seek out tags like “#nhfall” “#nhfoliage” or “#newenglandfall” for current images of conditions around the state/region.

If you plan to check out the foliage of the White Mountains by hiking, a weather forecast is important to check out in your planning as conditions can start to vary greatly from day to day and from base to summit where summits can start to experience full-on winter conditions. For expected weather 48 hours out, you can check our Higher Summits Forecast or, for a second opinion, NWS’s Recreational Forecast.

If Mt Washington is part of your fall foliage itinerary, it is important to check the various websites of the entities that share this mountain as shorter days and variable weather conditions (like snow) can affect their operations. You can find all their information at:

NH State Park

Mt Washington Auto Road

The Cog

Most of them have additional information on their various social media outlets too. If, after checking their sites or social media outlets, you are still unsure, it is best to contact the various outlets directly to ensure you are getting the most out of your travel time in the White Mountains. Mount Washington Observatory operates independently, so any questions about operating hours and day to day operations should be directed towards one or more of the groups listed above so that you are getting the best and most relevant information on any given day. Lastly, just in case the weather limits or closes operations to/from/on the summit, as I tell my family and friends, when it comes to Mt Washington, always have a “Plan B” just in case.

Fall foliage in late September at treeline along the Mt Washington Auto Road

Fall color along the Mt Washington Auto Road as seen Weds, Sept 18, 2019

Ryan Knapp, Weather Observer/Staff Meteorologist

Can I Bug You for a Minute? (Identifying an Insect on Mount Washington)

2019-09-21 09:37:56.000 – Tom Padham, Weather Observer/Education Specialist

While enjoying a beautiful afternoon on the top of the tower I stumbled upon an interesting looking beetle and decided to take a photo just for fun. It was a picture perfect day with light winds and I was actually painting the very top of our tower, taking advantage of the rare, nearly calm wind conditions on Thursday. I’m very glad I stopped to take this photo. After doing a little bit of research to identify the species and inspect the photo further it turned out to be a fascinating (if not a little gross) story learning about the life of this bug!

After doing a bit of background research, I am fairly certain this beetle species is Nicrophorus Tomentosus, or the Tomentose Burying Beetle. The beetle does look a little similar to a bumble bee, likely as a way of discouraging it from being eaten by birds or small mammals. This is a species of carrion beetle, usually found lower down in the forests of eastern North America. Burying beetles bury or cover the small remains of animals like birds and rodents, and help to clean up the forest floor in a way. They reproduce and lay eggs near a newly found carcass after secreting a fluid that actually inhibits the growth of mold and bacteria, which would compete with the development of their larvae.

Fascinating and gross at the same time I realize, but wait, there’s more! Take a closer look at the photo of the beetle. Along portions of the head and abdomen (thorax) there’s several small orange shaped mites! Initially I did not even notice these, and then when I did I thought they must be parasitic to the beetle. It turns out this is almost the opposite of the truth!

These small mites actually have a bit of a symbiotic relationship with the beetle, where both parties gain from the presence of the other. The mites mostly feed on the eggs of flies and maggots that are located around carrion, and compete with the beetle larvae. The mites and beetles work together to clear off the carcass of these competitors, and basically contain the carcass into a small little pit that the beetles dig out and cover. The mites then hitch a ride on the beetle, since the beetles can fly and otherwise the mites would have a pretty tough time moving from one place to the next.

I find it always fascinating learning about the natural environment and how sometimes very small creatures can have such an elaborate story to tell. It always helps to take a moment to stop and look around, and I’m certainly glad I did this time. Thanks for reading and sorry if I bugged you (or grossed you out) for just a minute!

Tom Padham, Weather Observer/Education Specialist

Bring on the Wind!

2019-09-18 10:23:23.000 – Eric Kelsey, Lead Research Scientist

The next step in ensuring a long future of research-quality wind speed measurements occurred this summer when the next-generation pitot static tube anemometer was disassembled and modified to fix a couple of problems that arose this spring and summer. In the spring when temperatures began to rise above freezing regularly, we noticed occasional spikes in wind speed that looked unrealistic. While we expect the NextGen pitot to measure higher wind gust speeds than Pitot 19 (our operational pitot) because of significantly shorter tubing, some gusts were over 40 mph higher with no sign of a big gust from the Pitot 19.

Given all the data we had, we correctly suspected water was getting into the slip ring, which is located in the top of the mast. When we disassembled the NextGen pitot in June, our suspicions were confirmed – we found water marks and rust on the inside. Fortunately, all we needed to do was remove the slip ring – problem solved! The purpose of the slipring was to prevent twisting of wires coming down the mast from the heaters and pressure-transducers. However, this is not a big problem because the wind does not turn over 360 degrees very often – only a few times a year. Observers can easily identify when this has happened, and they can simply go to the top of the parapet and turn the pitot around to unwind the wires. They already do this for the Pitot 19.

After the rewiring was completed, we reinstalled the NextGen pitot on the parapet on August 13th. It has performed terrifically through many rain and high humidity events since then – it appears removing the slipring worked.

The wind has been moving at its typical late summer snail’s pace since the NextGen pitot was reinstalled. But in the last week, sustained winds have reached 60-70 mph a few times. The next real test will be the next time the summit sees strong winds gusting over 100 mph with rain. We have every reason to believe the NextGen pitot will perform flawlessly in any conditions on the summit – and we will eagerly await fall and winter’s wrath to put the NextGen pitot to the test. Bring on the wind!

The Next Generation pitot tube system (dark gray pitot system on the left) is a collaboration with General Electric and University of Massachusetts-Lowell Engineering. Left to right: Eddie Walton (GE), Keith Garrett (MWO), Joe Chaves (GE), Pete Gagne (MWO), and Eric Kelsey (MWO).

Eric Kelsey, Lead Research Scientist

Types of Icing Events on Mount Washington

2019-09-17 14:23:48.000 – Ben Charles, Intern

The second week of my fall internship here at the summit of Mount Washington has been an eventful one. It had been since my first shift on the mountain back in late May since I have seen sub-freezing temperatures on the summit, but we were lucky enough to see temperatures dip below the freezing mark twice last Thursday and Friday! However, we were in the clear both times we got below freezing so we didn’t see much freezing other than some surplus trail runoff. Yesterday was a different story, I was in a deep slumber in my room and woke up to a rather loud clanking sound. I immediately knew that we must have gotten below freezing and it had to be our night observer Jay deicing the instruments on top of the tower. So I jumped out of bed to see my first rime ice event which I have been waiting oh so very patiently for. When I got up to the weather room and looked out the window, through the fog I didn’t see the white brittle rime ice covering the rocks, but was surprised to see a glossy coat of glaze ice. But what is Glaze ice?

Glaze ice unlike rime ice is very dense and looks and is very similar to the ice that forms when there is freezing rain typically being smooth with a waxy appearance. Freezing rain can create a glaze of ice, but the ice we received yesterday was from a cloud. Glaze ice and rime ice can both form in the same way. Both can form from supercooled water droplets inside of a cloud colliding with an object and freezing, and in this case the object is the summit of Mount Washington. The stronger the winds the more supercooled water droplets that will collide into the summit resulting in increasing accumulations.

To start rime ice forms when temperatures are well below freezing and when the supercooled water droplets are rather small most likely to be seen in a stratiform cloud. Upon impact, the surface must be well below 32°F letting the supercooled droplet to instantly freeze without spreading from the point of impact. The instantaneous freezing of rime ice allows the drop to keep their spherical shape causing air pockets to remain within the ice. This gives rime ice that opaque look and brittle consistency. This is also another type of rime ice called hard rime ice which is denser than normal rime ice. This is because it has less supercooled droplets and more ice crystals within the cloud.

A heavy coat of rime ice on the summit and Tip Top House taken on March 20, 2018

Glaze ice will form in a very similar fashion although in warmer temperatures just below freezing. Typically with warmer temperatures, the air can hold a bit more moisture allowing for the supercooled droplets to have larger diameters these drops are more likely in cumuliform clouds. So when the supercooled drops are rather larger, they must impact a surface that is only a few degrees below freezing or right at the freezing mark. This way when the supercooled drops hit the surface the entire drop won’t immediately freeze, the majority of the drop will disperse and spread across the surface. Then after dispersing it will eventually freeze giving it the glossy smooth surface with no air pockets within the ice.

Glaze ice forming on top of the tower on Monday September 16, 2019

All of the types of icing events can create dangerous conditions on the summit, so be sure to watch out for icing events in our higher summits forecasts and current conditions before hiking. Not only does rime ice and glaze ice create slippery dangerous conditions, but they also cause some major problems to our wind instruments. It doesn’t take much rime ice or glaze ice to accumulate on the anemometers to lock up the joints preventing the RM Young’s propellers from spinning and recording winds and preventing any of the wind instruments from properly vane in the wind. When this happens an Observer or intern like myself will have to go up and de-ice the instruments, which I was able to do for the first time yesterday morning! Although I haven’t experienced a rime ice event just yet, the glaze ice we received Monday morning was an incredible weather phenomenon to experience.

Ben Charles, Intern

Lenticular Clouds and Mt. Washington

2019-09-16 11:03:58.000 – Ian Bailey, Weather Observer/Education Specialist

Yesterday, we had some incredible views of some Lenticular clouds over the summit! Once we cleared from the fog, I had gone outside for the hourly observation and was pleasantly surprised to find some towering “lentis” in front of me! I quickly dug out my phone and snapped the picture, luckily before my phone was blown out of my hands and down on to the deck (needless to say I’ll be swinging by the iGuys in North Conway this coming down week). But it was worth it, as these were some of the best lentis I’ve seen in quite some time!

Once we posted the image online, lots of people were reaching out to us and asking us to explain what lenticular clouds are. So I figured I’d post a brief blog today to explain what exactly lenticular clouds are, and how they form!

When a strong air current flows over a large obstacle, such as a mountain, it creates a oscillating wave pattern on the lee side of mountain (known as lee waves). This happens fairly regularly around here, as the topography of the Presidential Range (among other factors) creates a powerful current that flows up and over the summit of Mt. Washington. So we have these lee waves oscillating up and down through the atmosphere on the backside of the mountain, which is the first piece of the puzzle.

Now add some moisture into the equation. Warmer moisture from the lower levels is rapidly brought up the side of the mountain, forcing it to cool quickly. As the moisture blasts over the summit and into the lee side of the mountain, it will enter the lee wave pattern and follow along the oscillating path. At the crest of each wave, if the ambient air temperature reaches the local dew point temperature, condensation occurs and a cloud will form!

So what gives the cloud its unique shape? Well, as the moisture/cloud continues to follow the wave pattern, it will descend back into warmer ambient air temperatures and evaporate once again. What’s going on is the cloud/moisture is visually disappearing as it turns back into water vapor. So, what we seen in effect is a stationary, lense shaped cloud as air is continually condensing and then evaporating along this wave!

And when this wave pattern is particularly strong, you can have some other interesting effects as well. If the oscillation is powerful enough to continuously reach the dew point level repeatedly, you can have lines of “marching” lenticular clouds across the sky, as in this picture!

Additionally, as was the case yesterday, the current of air flowing over the summit can cross at multiple different levels of the atmosphere, particularly through the dew point level, and create a stacking effect where the lenticulars look like a stack of pancakes! This is a bit more common than the marching lenticulars, and happens fairly often up here at Mt. Washington!

Check out some more of these past photos I’ve taken of lenticular clouds from here on the summit:

We get to see some very awesome things up here, especially with clouds. And Lenticular clouds are by far my favorite to see! So hopefully this helps make clear how these crazy cool clouds form. And maybe you’ll be lucky enough to witness them yourself someday (if you haven’t already)! Until next time!

Ian Bailey, Weather Observer/Education Specialist

When do we Average seeing our First Snow?

2019-09-13 15:29:53.000 – Adam Gill, Weather Observer/IT Specialist

With winter coming fast in the White Mountains, it is always fun to look back at our records and figure out some averages. Since we are technically a sub-arctic climate on the summit, the first snow usually comes quite early relative to the surrounding locations. We have had a few good cold snaps recently with temperatures falling below freezing, though it has so far only occurred when we have dry air in the region so no snow yet.

Finding the first snow of the year ended up being a bit more of a challenge since for me, I wanted to know when the first true snow fell. Originally I had tried to find the first day after July 1^st in which we recorded snowfall in the precipitation accumulation column but ran into a snag since hail counts as snow fall since it is falling ice. That made the first average snow fall into early August which is just not correct. In order to make sure that it actually snowed, I cross referenced the recorded snowfall with the hourly observations that we do to see if there was snow, snow showers, or snow grains reported since all those fall into what you would typically think of as snow. I even removed ice pellets, also known as sleet, because even though it technically is a winter precipitation, it is just frozen rain drops and doesn’t have the crystalline structure you get with snowflakes.

So for our entire record, the average first day where we see true snow is August 31^st. This is thanks to seeing many early snow events in the first 30 years of our history. From 1935 to 1965, the average first snow was quite early, falling on August 29^th! In recent history, we saw snow showers on August 31^st in 2017.

For our most recent period from 1988 to 2018, our average is now September 5^th. It is a little later than it was but this is also just seeing our first snow of the season, not first accumulating snow. That will have to be saved for a future blog!

Below is a graphic that shows the probability of seeing snow on any given day of the year. We are starting to increase the chances each and every day with almost a 20 percent chance of seeing snow by early October! I am really hoping for a good snow storm above 4000 feet right around peak fall foliage to get the contrast of fall and winter here in the White Mountains!

Adam Gill, Weather Observer/IT Specialist

In Search of Wintry Weather: A Look at the Week Ahead on Mount Washington

2019-09-09 08:30:46.000 – Thomas Padham, Weather Observer/Education Specialist

With our much-advertised below freezing temperatures last night being a bust, (we sat at literally 32.0-34 degrees all night) I’ve decided to take a look at our next chances for potential wintry weather. “Wintry weather” we’ll define as at least some icing conditions, with rime or glaze ice forming on the summit surfaces, or better yet, snow! It’s still quite early for us to see significant snowfall this time of year, but typically by mid-late September the summit has seen our first snowfall, and riming or glazing conditions often occur earlier.

We did see some very brief glazing conditions for roughly an hour overnight on Wednesday the 4^th, but the amount of ice was very miniscule, and by the time the day observers had awoken the ice had already melted. This past weekend looked much more promising from the models, but temperatures ended up being a solid 3-4 degrees warmer than expected through the night. The weather models we use for our forecasting tend to have some “hiccups” this time of year as we transition from summer towards fall. This is due to a built-in equation change as we head towards winter, and sometimes that change should have happened sooner or later depending on the type of short term weather pattern we’re currently seeing across the area.

Taking a look at the big picture weather over the next 10 days or so, we’ll have a few chances at some below freezing temperatures and at least some glaze ice. Glaze ice is formed near the freezing mark, from liquid water that has settled onto surfaces and then slowly freezes. This is the same as ice we see with freezing rain, and can be very slick and also a pain to remove from our instrumentation. It’s my least favorite type of weather up here, but it’s still wintry!

Some of our anemometers really don’t do well with heavy glazing conditions, normally we bring this instrument inside before this happens!

Temperatures are expected to warm up significantly over the next few days, with a warm front and rain showers Wednesday allowing temperatures to surge up into the 50s. Behind this system we could have a chance at reaching just below 32°F overnight Thursday the 12^th into Friday the 13^th, but it’s not looking all that likely and also there’s a fair chance the summit will not be in the clouds during that time.

GFS Model sounding for Mount Washington on Sept 19th showing well below freezing temperatures at 800mb and saturation (fog) occurring. If this pans out we would likely see our first riming event of the fall season!

Getting way ahead of ourselves, in the even longer term the GFS has shown a more significant storm and associated cold front crossing New England sometime during the middle of next week (the 18^th and 19^th). This one has consistently had below freezing temperatures for the summit, possibly getting down towards the lower 20s. With some residual moisture this would also lead to our first real chance for some snow showers. It’s still over a full week away but I’m hopeful to see our first taste of snow on our next shift!

Bring on winter!

Thomas Padham, Weather Observer/Education Specialist

September 2019

Flux Tower Project III

Western Snow and a Look Ahead

A Taste of All Seasons

Information For Autumn

Can I Bug You for a Minute? (Identifying an Insect on Mount Washington)

Bring on the Wind!

Types of Icing Events on Mount Washington

Lenticular Clouds and Mt. Washington

When do we Average seeing our First Snow?

In Search of Wintry Weather: A Look at the Week Ahead on Mount Washington