22:13 Thu Sep 21, 2017
This Heat Though...
Being a meteorologist, people frequently ask you what the weather is going to be like for the coming days and expect an immediate answer. Unfortunately, we meteorologists do not always have the answer at that moment and need to access forecast models before giving an answer. This is especially true for me when I work a one week shift and then have the following week off. My girlfriend, Molly understands this thankfully and accepts the fact that I am not actually an all-knowing psychic. I think sometimes she wishes I were though because then we would have a massive flow of money coming in from my weekly DraftKings and FanDuel winnings. Also, my forecasts would be even more accurate than they currently are at 99.4%, which could boost the earnings… This past week I was especially oblivious to the upcoming weather, compounded by the fact that we were extremely busy after spending the majority of the week down in Florida.
Molly was getting ready (On Tuesday…) for a wedding that she and I are attending this weekend and she asked what to expect weather wise. I took the quick and easy way out, pulled up one of my trusted weather apps, and typed in the location of the wedding. Looking at the expected temperatures, I thought my eyes were lying as I saw 88°F for Saturday and 90°F for Sunday. We had just arrived back to Vermont after spending time in Florida, and apart from the fact that we were away from family again, I was ecstatic to return to the New England climate and away from the oppressive Florida heat and humidity. I quickly discovered that this un-Caleb-friendly air mass was stalking me and looking to greet me this weekend for the wedding in New York. Typically, I pray that these warm snaps occur while I am in the comfort of my summer time permanent air conditioner (Mount Washington), but in this instance I will be leaving its comfortable summertime grip and descending into the sultry, sweat-causing, asthma-inducing, igloo-destroying heat. I am excited to be with Molly to celebrate our friend’s marriage, but rest assured I will not be wearing a gray dress shirt.
After seeing 88°F and 90°F temperatures forecasted for a late September day, I had to dive a bit deeper into the forecast to see exactly what was going on and how it would translate to the temperatures atop the Rockpile. This significant warm up has been ongoing since September 11 when our daily average temperatures began to read higher than normal. The culprit is a massive ridge over the eastern half of the United States, which has allowed the warmer air to stream northward. Through the end of the next workweek, which will take us to the end of September, this ridge is showing no signs of letting up. As a result, the mercury will continue to soar each day, especially with abundant sunshine in the forecast that will help the temperatures to warm even further. September started unseasonably cool; however, our daily average temperature this month has now risen to 45.6°F thanks to the many consecutive days above normal. This weekend, it is very possible for consecutive daily record highs to be set as the core of the warmer air anchors itself over New England. Currently, our average temperature for September lands as the fifth warmest on record. With the warmest temperatures still to come, we will approach the warmest September on record for Mount Washington, which was 49.3°F in 2015.
Pictured above is the GFS Extended Model Output Statistics which give a rough estimate of the temperatures to expect through the next week. The current daily records are in jeopardy beginning Saturday and continuing through most of next week. The current records compared to the forecasted temperatures are as follows:
September 23rd Record – 62°F
September 24th Record – 62°F
September 25th Record – 62°F
September 26th Record – 59°F
September 27th Record – 62°F
September 28th Record – 61°F
Caleb Meute, Weather Observer & Staff Meteorologist
15:22 Tue Sep 19, 2017
The Fujiwhara Effect
A few weeks ago, I wrote a post about the formation of hurricanes, to usher in the start of the hurricane season. Since then, we’ve seen multiple tropical cyclones form, even concurrently! Sometimes, these systems appear to revolve around each other as they move across the oceans. This is known as the Fujiwhara effect, after Japanese Meteorologist Sakuhei Fujiwhara, who first observed the phenomenon in a paper in 1921 describing the motion of vortices in water.
As the paths of two tropical cyclones pass within proximity of each other, they begin to interact. Fujiwhara found that as tropical cyclones approach each other, they begin to rotate counter-clockwise about a central point, with the degree of interaction increasing as the distance between the two systems decreases. Further studies have shown that the degree of interaction is dependent not only on the distance between the storm centers but also the strength and size of each storm as well as the overlying environmental setup.
There are two main scenarios possible when tropical systems begin to interact. The first is depicted in Figure 1 below, where the two systems begin to orbit about a central point and then eventually break free.
Figure 1. Fujiwhara effect resulting in two orbiting cyclones that break away. Photo from Hong Kong Observatory
The second scenario typically involves storms of two separate strengths. In this case, the weaker storm will typically orbit around the stronger storm and eventually be absorbed into the bigger system. Figure 2 below, shows the effect of a smaller storm being wrapped around and absorbed into the larger circulation.
Figure 2. Fujiwhara effect resulting in merger of two tropical cyclones. Photo from Hong Kong Observatory.
There are several instances in recent memory of tropical systems engaging in this delicate “dance.” One such example is when tropical systems Hilary and Irwin pivoted around one another as they continued to move northwest prior to Hilary absorbing Irwin this past year.
Figure 3. GOES-16 over the Pacific July 25 - August 1 2017. Image from the Weather Channel.
Taylor Regan, Weather Observer
14:29 Sun Sep 17, 2017
Tracking Jose and the Tropics
Jose is a long lived tropical system, having formed back on September 5th. Jose will likely remain at least a tropical storm through next Friday, the 22nd, giving it a total lifespan as a tropical system of 14+ days. This is still not even close to the longest-lived tropical system, Hurricane John in 1994. John formed as a hurricane in the far eastern Pacific off the coast of Mexico on August 11th, 1994. 31 days later, on September 10th tropical storm John finally dissipated south of the Aleutian island of Alaska after having traveled 7,165 miles!
Hurricane John's track across the Pacific in 1994.
Hurricane Jose reached peak intensity as a Category 5 with 155 mph on September 9th. This was the first time in recorded history in the Atlantic that two hurricanes with winds of 150 mph or greater occurred at the same time, with Hurricane Irma moving just offshore of Cuba at the time with 150 mph winds.
NOAA GOES-16 Visible Satellite showing Hurricane Jose off the Eastern Seaboard on 9/17
Jose is expected to track northward from its current position about half way between Bermuda and the Carolinas before making a northeastward turn south of New England. This current track should luckily keep most of the storm far enough away for little in the way of impacts other than rain to areas from Boston northward. Along Cape Cod and especially the islands just offshore of New England like Martha’s Vineyard, tropical storm conditions will still be possible due to the large size of the storm, with impacts from beach erosion and high surf likely along much of the coastline. Any further deviation slightly closer to the close of the track of Jose would potentially bring stronger winds further inland, possibly affecting the Boston metro area.
Hurricane Jose official forecast track and predicted strength at the 11:00 AM EDT update
This has already been a very busy Atlantic hurricane season, with 14 named storms as of this writing. An average hurricane season has only 10 named storms, so we’re already above the average year despite still having through November for the typical season. Besides Jose, tropical storm Maria bears attention due to it’s predicted track and strength.
Maria is forecasted to become a major hurricane as it tracks across the Leeward Island and towards Puerto Rico, both areas that were recently hit hard by Hurricane Irma. By Friday the storm will likely still be a hurricane just north of the island of Hispaniola. After this point the hurricane could continue a northwestward motion towards the East Coast, or potentially be turned northwards and take a similar path to that of Jose.
Tropical Storm Maria official forecast track and predicted strength at the 2:00 PM AST update
With the damage of Harvey and Irma still fresh in the minds of the entire country it serves as a reminder that we all should be prepared in the event of any natural disaster. For help starting your emergency preparedness kit, head to https://www.ready.gov/build-a-kit. The National Hurricane Center at http://www.nhc.noaa.gov/ is a great resource with information on how to prepare for a natural disaster. Our fellow Americans could still also use your support in the ongoing clean up and rebuilding after Irma and Harvey; consider making a donation to the Red Cross for disaster relief at https://www.redcross.org/.
Tom Padham, Weather Observer/Education Specialist
14:36 Fri Sep 15, 2017
Seeing the Many Faces of the Summit
Mount Washington is not only home to the world’s most extreme weather; it also harbors extreme contrasts in weather. With just two shifts under my belt on the mountain, I’ve experienced two very different environments.
My first week (Aug 30 – Sept 6) was a whirlwind. Not only was I learning the duties of an intern on the mountain (it never ends); we also experienced a wide range of mountain weather including clear summits, rain, rime ice accumulations, a trace of snowfall, and thunderstorms. The wind showed up as well, topping out with a gust of 94 mph on September 1st. When not forecasting local summit and valley weather, the observatory was abuzz with Hurricane Irma’s forecasted track. Irma quickly intensified to 185 mph sustained winds, placing it in a four-way tie for second highest in the Atlantic basin (shared with Labor Day 1935, Gilbert (1988), and Wilma (2005)).
Fig 1. An early morning peek in between altocumulus and stratus clouds.
Just one shift later, the summit is a bit calmer. After making landfall in the Florida Keys, Irma’s remnants slowly traversed the South and made their way to the Northeast. Passing through at the beginning of the shift, Irma’s leftovers ironically provided unusually calm winds for the summit. The system also brought localized moisture over the Northeast producing scattered showers and storms during the day with distant light shows visible at night. On a grander scale, a large ridge has lifted the jetstream north into the southern tier of Canadian Provinces. Normally in the low to mid-40s, southerly winds have fed the White Mountain region with above average temperatures in the upper 50s on the summits. On September 14th, we tied our daily record temperature of 60 degrees!
I’m learning among the faces I see on tours and in the Extreme Mount Washington Museum, that the mountain itself has many faces of its own!
Greg Cornwell, Summit Intern
10:34 Wed Sep 13, 2017
Winds of Mt. Washington vs Hurricanes
Working up here I have always been curious as to how our winds compare to that of hurricanes in regard to force. The summit and sea level have different atmospheric densities. So, if the summit and a place at sea level have the same velocity, the wind at sea level would feel stronger due to a greater density. In hurricanes, the highest winds will occur in the eye wall so the pressure is fairly low compared to normal sea level pressure. The temperature is also very warm along with high humidity which helps lower the density even more. On the summit, since we are at elevation, we are above 20% of the atmosphere but with most of our high winds in winter, it is extremely cold and that can increase the density.
Checking out the surface data from Hurricane Irma, I found that in the eyewall at landfall the pressure was around 938 millibars (mb) and the temperature was around 81°F with a humidity of ~95% the density was 1.074 kg/m^3. On the summit, our typical pressure in winter is around 800 mb and the temperature averages are in the lower teens so let’s say 12 degrees with 100% humidity since we are in the fog most of the time. The density I got was 1.062 kg/m^3, which is not too much of a difference from the eyewall of Hurricane Irma.
Our pitot tube that we use to measure wind velocity is hooked up to a pressure transducer that measures differential pressure. We are basically measuring the force of the wind rather than using an anemometer that rotates because it is more accurate in harsh conditions. I can use the force measurement from the pitot to be able to calculate the equivalent velocity in hurricane Irma by correcting the wind speed for the different density that was calculated earlier (1.074 kg/m^3).
The highest wind speed that I have experienced on the summit so far was 138 mph. At the time of the gust, the temperature was 5°F, the pressure was 778.48 mb, and the humidity was 100% leading to a density of 1.046 kg/m^3. The pitot measured a differential pressure of 8.05 inches of water so I can use the 8.05 inches of water and change the density to 1.074 kg/m^3 to get a new velocity 136 mph in Irma’s eye wall. So the 142 mph recorded in Naples felt stronger than what I have experienced! The difference is not quite as great as I thought it would be when I started to look into this. I was expecting the winds near sea level in a hurricane to be exerting a greater force for the same wind velocity.
We can go a step further and look at the greatest wind velocities that were recorded in the hurricane and look at what the equivalent wind speed would be on the summit if the force was kept the same. The highest wind speed that I could find from Irma was recorded on Barbuda at 155 mph (this anemometer failed and gust likely were higher), the pressure at the time was 922 mb, temperature of 76°F, and relative humidity we can assume again at around 95%. This resulted in a density almost similar to the summit at 1.063 kg/m^3. This would mean that the differential pressure would have been 10.3 inches of water and we can then correct once again for the typical density we have up here in high wind events so the wind equivalent is 155.3 mph. Now since we have a wide range of temperatures and pressures on the summit, the range that the wind speed could have been is 150.1 mph on really cold days to 163.1 mph if it occurred during the summer.
Adam Gill, Weather Observer/IT Specialist
17:23 Sun Sep 10, 2017
Walking In A Winter Wonderland...Almost
With the changeover to meteorological fall comes the increased possibility for snow on the summit of Mount Washington. During my time on the summit as the summer intern I was able to truly experience snow and icing only once at the very beginning of my internship. The summit seemed to be a winter wonderland with everything covered in frozen precip; whether it is ice or what was left of the blowing snow. With my experiences from that one event, I am positive that when this winter season fully comes underway I will be in awe of the beauty of the snow and ice.
Figure 1. Rime and glaze ice covering the observation deck on my first week as an intern.
Mount Washington’s winter is longer than the typical winter season. The season ranges from October to May averaging a whopping 281 inches of snowfall. With the winter season coming fast and the first few snowfalls this season underway it is the perfect time to understand the beauty behind these frozen flakes.
The typical visualization of snow is a beautiful, lacey, symmetrical snow flake. While this may be one type of snow crystal it is not the only type that can form. Snow may fall in many different shapes and sizes depending on its unique path through a cloud. Changes in temperature and moisture will grow different shapes and sizes of snow crystals. A single cloud does not have uniform moisture or temperature within it. Therefore, the same cloud can produce differently shaped snow crystals.
Figure 2. A chart showing different snow crystal structures and their dependence on temperature and humidity within a cloud.
Nicole Tallman, Summit Intern
Looking at the visual above it is clear that there are a variety of shapes to snow crystals, not just the dendrite that we are all so familiar with. For example, temperatures from around 10 to 20 degrees Fahrenheit can produce needles, columns and prisms while colder temperatures from -10 to -20 degrees Fahrenheit will produce columns and plates. The moisture within the cloud will have a direct correlation to the size of the crystal; more moisture can produce larger crystals. Along with moisture there are two other ingredients needed to produce a snow crystal. Snow will form with water vapor, dust (in the form of pollen, volcanic ash or other particles in the sky), and ice crystals. These three ingredients along with the right meteorological conditions will produce snow.
The snow typically seen on the summit of Mount Washington is produced with temperatures ranging from -10 degrees to 10 degrees Fahrenheit. This means that we see many of the familiar dendrites as well as plates.
Last winter the summit received 401 inches of snow which was 120 inches above average making it the 6th snowiest winter on record. The most significant storm that hit the summits was at the end of their winter season and fell on Mother’s day from May 14th through the 15th dumping 33 inches of snow! It was a very impressive winter (still not enough to satisfy our snow enthusiast observer, Adam)!
Figure 3. A photo from the August 31st - September 1st rime and snow event. The first event of the season.
So far this winter season we have had two snow events. The first event lasted from August 31st- September 1st and the second was on September 8th- 9th. Both only produced traces of snowfall but that is enough to get the crew exited for winter. I may be reluctant to have the cold weather come back but I know I will enjoy the winter wonderland that comes with the snow and ice on Mount Washington.
Figure 4. A early June sunset from my first week as an intern.
06:01 Sat Sep 09, 2017
Fires, Flares, Hurricanes and Earthquakes… Oh My!
Natural disasters have been in the news much too frequently these past few weeks, and Hurricane Irma looks to continue the dreadful trend as it aims to make landfall in southern Florida sometime Saturday night. It was just last shift that we sat up here in the weather room watching satellite imagery as Hurricane Harvey grew more and more intense as it neared the Texas Coastline. While Harvey was strengthening, we continuously watched the forecast models, which were showing the catastrophic outcome of it stalling out in southern Texas for up to a week. That was unfathomable… We sat here in disbelief thinking about what exactly that would mean for everyone in southern Texas, including the countries fourth largest city, Houston. Now it is two weeks later and my shift has found ourselves once again watching a historical storm that is looking to unleash unimaginable fury across Florida. By the way, there are also two more hurricanes in the Atlantic right now, Katia and Jose. Hurricane Jose has rapidly strengthened today and (as of this writing) is just shy of category 5 strength… Two category 5 hurricanes in the Atlantic would be unprecedented.
Hurricanes have been dominating news stories over the past couple of weeks, but other significant natural disasters are occurring simultaneously. Wildfires have been raging over the Pacific Northwest for over a month! This image (below) taken by the NOAA-NASA’s Suomi NPP satellite on September 4, 2017 shows several of the wildfires and their associated smoke plumes spread all the way across the country by means of the jet stream.
Wednesday morning of this past week, the sun released a strong X2 solar flare that was quickly followed by an X9.3 flare, which was the strongest since an X17 flare occurred in 2005. X-class flares are the biggest type of flares emitted by the sun. The smallest ones are A-class, followed by B, C, M and X. Much like the Richter scale of earthquakes, each letter represents a 10-fold increase in energy output. Within each class of flares, there is a finer scale from one to nine. Within the X-class, there are flares that are ten times stronger than an X1, so X-class flares can go higher than nine. The strongest flare recorded was in 2003, which measured as an X28 before the sensors were overloaded. This particular flare on Wednesday caused high frequency radios to stop working on the side of Earth facing the sun and GPS communications were degraded for close to an hour. It also led to spectacular displays of the northern lights across the country as charged particles released from the flare collided with the gaseous particles in the Earth’s atmosphere.
Late last night, a powerful magnitude 8.1 earthquake struck Mexico just off its southern coast killing at least 58 people. The quake was felt by nearly 50 million people across the country and it was the strongest experienced in Mexico over the past 100 years.
Irma is stealing the show, but reasonably so. Many records have been set since its formation and unfortunately, it will continue to keep this record setting pace. Colorado State University meteorologist, Phil Klotzbach has been tracking all of the records and I will highlight some of them below. For the full list, follow this link: https://webcms.colostate.edu/tropical/media/sites/111/2017/09/Hurricane-Irma-Records.pdf
185 mph lifetime max winds – Tied with Florida Keys hurricane (1935), Gilbert (1988) and Wilma (2005) for the second strongest max winds of all time in an Atlantic hurricane. The only strongest was Hurricane Allen in 1980 which had max winds of 190 mph.
185 mph lifetime max winds – The strongest storm to exist in the Atlantic Ocean outside of the Caribbean and Gulf of Mexico on record.
185 mph max winds for 37 hours – This represented the longest that any cyclone around the globe has maintained that intensity on record. The previous record was Haiyan in the NW Pacific which maintained those max winds for 24 hours.
914 millibar lifetime minimum central pressure – Lowest since Dean (2007) and 10th lowest in satellite era (since 1966)
914 millibar lifetime minimum central pressure – Lowest pressure by an Atlantic hurricane outside of the western Caribbean and Gulf of Mexico on record.
3 consecutive days as a Category 5 hurricane – The longest in the satellite era
Hurricane Irma is showing no signs of weakening prior to making landfall in southern Florida. This storm is massive and will undoubtedly bring devastation to Florida, especially along the coastline where it makes landfall.
It has been an active month for natural disasters with an enormous amount of people already affected. In addition to those already affected, there is now a huge population bracing themselves for a historic impact from Hurricane Irma. My thoughts and prayers are with everyone affected by Hurricane Harvey, the wildfires in the Pacific Northwest, the earthquake in Mexico and now Hurricane Irma.
Caleb Meute, Weather Observer / Meteorologist
10:32 Mon Sep 04, 2017
My Introduction to Mt. Washington
My name is Greg Cornwell and I will be a Mount Washington Summit Intern this Fall. I completed my Meteorology and Information Technology degrees at Central Michigan University in December 2015. Before this, my interest in weather first came about when I was young and absolutely petrified of a clear breezy day or the sight of dark clouds. I believed all that was needed for nightmarish tornadoes was rain and wind. If both were occurring, I feared that I could be swept away at any time.
Growing up, fear turned to curiosity.
My first forecasting experience was in high school. Classmates knew about my fascination with weather and I anticipated the daily flurry of questions along the lines of, “are we going to have a snowday?” My reply usually was, “I forecast snow, not snowdays!” One of my good friends suggested hitting the blogosphere. Creating my own forecast discussions and event summaries improved my knowledge and understanding of weather. It made me double check how atmospheric processes are understood. While praise can be won following a good forecast, applying and conveying the correct science is what made the task rewarding for myself and readers.
In college, forecasting was part of class lab work as well as the WxChallenge. I performed these tasks with guidance from the great professors at CMU. It opened my eyes how advancement of instrumentation and computing has allowed us to better monitor extreme weather and more accurately forecast it. By senior year, we had a small group of students forecasting for the football team as they hosted home games and traveled away.
After school I traveled to Maine for a seasonal IT position at Acadia National Park. While not on my preferred weather track, I learned a lot about computer systems in an operational environment. Part of the job was supporting workplace technology for scientists with the National Park Service. Being around raw data, science, and research made me miss the environment I was immersed in at school. I began searching for a position that offered those qualities and have found it here at the Mount Washington Observatory!
Figure 1. The parapet with morning sun under broken clouds ahead of post-tropical cyclone Harvey
I’m looking forward to experiencing all the observatory has to offer. I could not ask for better mentors of the mountain than my shift observers. They have been there for any questions and guidance through a busy start of my tenure! Through the first 72 hours, I experienced a clear sunset, the summit in the clouds, and winter firing an early warning shot with rime ice, 94mph gusts, and wind chills approaching zero. As we enter meteorological fall, it is only just beginning!
Figure 2. Rime ice accumulations on the observatory deck binoculars. The first riming event included 94 mph gusts and wind chills in the single digits.
Greg Cornwell, Summit Intern