17:33 Thu Jan 17, 2019
Update on this weekend's Winter Storm!
On Tuesday, Observer Tom Padham wrote about the potential for an impressive winter storm for the Northeast this weekend. Like he said in his blog, we have been following the evolution of the storm so far, as well as what different weather models are indicating for the weekend ahead. Now that we are inside an appropriate 72-hour forecast window, I’d like to update you on how both the atmosphere and the storm of interest have progressed since the last post, and start to give a more concrete forecast for this approaching storm.
To start off the weekend, an upper-level disturbance associated with a shortwave jet stream feature will allow a low pressure system from the South-Central Plains to be drawn rapidly towards the Eastern seaboard. Given the relative West-to-East flow of the lower levels of the atmosphere, it is likely that this low will track a decent distance off shore, before banking left and running a loose parallel to the coast.
So while the low will not directly impact New England at its maturity, it will bring in a loose plume of moisture from down near the gulf. As this moisture propagates on the backside of the low headed North, it will inevitably produce loose and light bands of snow showers across the Northern part New Hampshire throughout the day on Friday. Accumulation totals across the regions have decreased a bit since Tuesday, and at present only a trace to 1 inch seems possible from these snow bands, Think of it as a very light taste of what’s supposed to come later in the weekend, which you can see forming over Northern Texas in the image below from the NAM 3K model.
NAM 3k model showing the locations of the Friday and Saturday/Sunday lows. Image courtesy of Tropical Tidbits.
So what happens next and what leads to this big storm headed our way? As it stands, it appears the dispersed energy from a strong low pressure system in the Northwest part of the country will reorganize near the Eastern Colorado border. A steep upper level ridge will build just West of the Rockies, which will allow for strong North-to-South flow that will transport that dispersed energy into the Southern Plains. This in turn will coagulate into a strong Jet Streak, or a high-velocity pocket of air in the upper levels of the atmosphere that generally leads to atmospheric disturbances and the instability necessary to build low pressure systems and develop storms. You can see this strong Jet Streak in the image below, and I’ve also circled where the low is likely to form and build following cyclogenesis on Saturday morning.
NAM model showing the locations of the Jet Streak and low formation. Image courtesy of Twisterdata.
Throughout this entire overnight process, the low is gathering warm, moist air from the Gulf of Mexico to fuel itself before its inevitable march Eastward. And with a number of blocking high pressures to the East and North, the low will continue to remain within striking distance of the Gulf for a significant period. The entire time, the system will be taking in and distributing moisture, building what will likely become a massive moisture plume by the end of the day on Saturday. Below is a picture from the ECMWF model runs of the low pressure on Saturday morning and Saturday evening for comparison.
ECMWF model showing a moisture comparison between Saturday morning and evening. Image courtesy of Tropical Tidbits.
You may notice that on the evening ECMWF run, the moisture plume has extended to reach the majority of New England. It’s truly impressive that while the center of the system remains in the Mid Atlantic, it has gathered and dispersed enough moisture that it is forecasted to precipitate as far away as Maine at the same time. And at this point, the low is only beginning to reach its point of maturity.
Overnight Saturday and into Sunday, the low will continue to propagate East, dumping large amounts of rain and snow as it moves. After crossing over the Appalachians and reaching the waters of the East coast, the low will ingest more available moisture and reach its peak intensity. And after sunrise on Sunday morning, the center of the low will crash into New England proper, producing some impressive rain and snowfall totals. By the end of the day on Sunday, 1.5 to 2.5 inches of a wintery mix of precipitation could fall across the Southern portions of New England, an approximately 16 inches of snow across the Northern portion where temperatures will likely remain at or below freezing. At the summit, we are even expecting snowfall totals near 20 inches!
ECMWF model showing rain and snowfall totals for Sunday Morning. Image courtesy of Tropical Tidbits.
This low will be a classic Miller Type B Nor’easter. Once these lows cross over the Appalachians and intensify, they are well known for producing a considerable amount of precipitation before they depart offshore. Additionally, with their tight pressure and temperature gradients, wind speeds will be on the rise as well. I’d expect no more than 15 to 20 mph near surface levels, particularly on Sunday night in Monday as the storm moves off. But on the summit, we could see winds ramping up into the 100 mph range as the low centers in.
Ian Bailey, Weather Observer/Education Specialist
Definition and Progression of a Miller Type B Nor'easter. Image courtesy of the National Weather Service.
Additionally, if we look just outside the forecast window in MLK Day, temperatures are likely to plummet following the low’s associated cold front. Subzero temperatures are not out of the question for most of New England, including New Hampshire, Vermont, Massachusetts and Connecticut. So it certainly has the potential to be a frigid, blustery holiday.
It certainly is a lot to take in. But the takeaway here is that the models agree with the strong potential for a Nor’easter to blast the coast by the end of this weekend. States further South can likely expect heavy amounts of rain and wintery mixes in precipitation, while the Northern states are in for a considerable amount of snow. And in this winter storm’s wake, a brief period of elevated winds and frigid temperatures would be expected; even more so here on the summit of Mount Washington.
Model agreement is high and consistent, NWS offices are putting out Winter Storm Advisories, Watches and Warnings, and with each passing day the atmospheric structure proves to be more and more conducive for a big storm. We will continue to monitor the storm's progress over the course of the weekend, and will certainly be outside Sunday morning for our Facebook Live update to check it out! It looks like it’s going to be quite exciting, so make sure to stayed tuned in the coming days as we track this impending Nor’easter! And be sure to check out our forecast products on our website for more information!
13:12 Tue Jan 15, 2019
Potential Weekend Storm
A significant storm for the upcoming weekend has now been consistently in the models over the past several days, and it could be an impressive storm for much of New Hampshire and New England. I thought it would be good take a look at the current models and see the things that are closer to a certainty, and also those that are more “up in the air” for this weekend. First off, let’s back up a little bit and see how the weather is looking ahead of this weekend.
A weak clipper system will cross through New England tomorrow, mostly impacting the northern half of the region with some snow showers, gusty winds, and a reinforcing shot of colder air. Particularly in the mountains we could see some briefly heavy snow via snow squalls tomorrow afternoon and evening, with even a rumble of thunder not out of the question. Snow accumulations for the summit will likely be in the 1-3” range, although if any squalls track directly overhead we could see slightly higher amounts.
3 KM NAM model showing potentially heavy snow showers crossing northern New England Wednesday afternoon. Image courtesy of Tropical Tidbits.
After a break in the action Thursday, another relatively weak system will track through southern New England for Friday, with a light but widespread snowfall for the area. This will luckily be a quick mover, likely starting early Friday morning and ending by the late evening the same day. It will however, be a negative impact on driving as the area looks to receive 2-4” of snow, just enough to be a nuisance for driving, or great for skiing!
Then attention turns to the much more significant storm. This system is just starting to impact the West Coast tomorrow and Thursday, at which point the models will likely have a much better understanding of how it will evolve over time as it crosses the country. After producing heavy rain and snow in the West, with up to 5 feet of snow in the Sierra Nevada mountains, the storm will redevelop in the lee of the Colorado Rockies Friday. By Saturday the system will be picking up a significant amount of moisture as it tracks across the Mississippi River, quickly pushing snow into the Northeast during the overnight hours.
Temperatures will be cold enough for snow statewide as precipitation begins in earnest by midnight Saturday, with potentially heavy snow during the predawn hours Sunday through the afternoon. What’s still uncertain is how far north warmer air will push in, allowing for a changeover to more of a snow/sleet mixture. Along the coast there could briefly be some freezing rain as well, but eventually warmer air will win out here allowing for a changeover to plain rain. Across the higher elevations of the White Mountains like Mount Washington and for points further north, precipitation should remain all snow.
GFS model showing potentially where the rain-snow line will be setting up Sunday morning. Image courtesy of Tropical Tidbits.
By the time the storm departs Sunday night we could be looking at a widespread area of near one foot of snow, with localized higher amounts. The summit will almost certainly see 100+ mph winds either during or just after the storm departs, and there’s also the potential for near-record cold on the backside of this system for early next week. It’s going to be a very active and exciting time to observe the weather on Mount Washington, we’ll continue to monitor this storm over the next few days as it develops and hopefully witness some of the extreme winter conditions we’re famous for!
24-hour snowfall amounts from the potential storm late Saturday night through Sunday night. This is just one solution, but many areas in interior New Hampshire and Maine may see roughly one foot of new snow. Image courtesy of Tropical Tidbits.
Tom Padham, Weather Observer/Education Specialist
10:05 Mon Jan 14, 2019
A Once In a Lifetime Experience
When I was younger in middle school, I visited New Hampshire for the first time back around Thanksgiving of 2006, my family drove near Mount Washington for the first time ever and fell in love with the mountains and the sights. My dad showed me videos of what it was like up and seeing videos on the television of how extreme it can get. I wished to get the chance to be up there one day. In January of 2014 I visited Plymouth State University just about an hour away, and found out about a winter internship opportunity at the Mount Washington Observatory. Between that and a great meteorology program, I knew I had a chance to fulfill a dream.
I waited until my junior year of college to apply for the internship, since I knew it only took juniors or senior students mostly. I wasn’t able to get it the first time around. The second time around was key and is the proper way of sending me off into the future of meteorology. Knowing Id get to spend two weeks in some of the worst weather conditions possible in the world, I was ready and couldn’t wait for the day to come.
Since I was little: wild, bizarre, and brutal winter weather has been my favorite growing up in the Hudson Valley of New York. Blizzards and nor’easters are easily my favorite weather events to happen. Leading up to my internship I kept watching the weather and the pattern setting up to hopefully get a chance at a snowstorm and get some hurricane force winds while being at the Mount Washington Observatory. The pattern seemed a little tranquil at first, but things began to shape up in my favor.
It seemed perfect the beginning of my internship, my first day up would be the “calm before the storm” as it was a picturesque day at the base of the Mt. Washington Auto road to load up on the snow cat to get set for the shift change. The following day had snow in the forecast, so I was already giddy with excitement. The ride up the auto road was beautiful as the Atlantic Ocean could be seen while riding up, and the views were just breathtaking and there was so much to take in at once.
When we got to the summit, it was hard to believe I was up there, especially in January, the best time to be up on a mountain. There was visibility of 130 plus miles. Going to bed that first night was hard as I knew snow was coming and I wanted to see what it was like up there with the snow and wind. I woke up around 4:30 AM and was ready and excited. When I went up to the parapet with moderate to heavy snow and winds up to 70 mph, I felt like I was dreaming. It had me pumped up and excited to be feeling snow hitting me like tiny stones at a high rate of speed, even if it made my face a bit chilly. The observers said I haven’t seen anything yet as winds were about average and that I should wait until we get over 90 mph and over 100 to see what that is like. I wondered then if I’d get the chance of getting over the century mark for winds.
That opportunity would come over the first weekend, and it put me at another level of excitement. Nothing is like 100+ mph wind gusts ripping across the deck or over the tower while deicing instruments. The pure force of nature made me feel like a child in a candy store. And then later in the week we got a bigger storm that brought in winds gusting over 110+ mph and those winds were just unbelievable. We got around 20” during a two-day span of synoptic snow and a good upsloping snow event. We even got VERTICAL snow to start the synoptic event as winds were calm and tranquil.
The sunrises and sunsets were unbelievable and hard to put into words what they are like. The beautiful glow off the top of the White Mountains after some fresh snow and rime ice. Mother Nature is a beautiful and powerful thing and is often underestimated.
While up here at the Mount Washington Observatory, it was awesome working with both shifts and learning the processes of what goes through forecasting and managing the observatory. Between educational trips spending overnights here at the summit to helping with Facebook lives, it was a fun experience and I feel I have learned some valuable skills in the 2 weeks I have been here at Mount Washington. It was a once in a lifetime opportunity that I will remember forever and hope I can come back again to experience more thrilling and extreme weather here at the Mount Washington Observatory.
Stephen Durham, Summit Intern
10:45 Thu Jan 10, 2019
The Deep Freeze is Here!
We’ve had plenty of extremes so far this winter season on the summit of Mount Washington, from high winds to whiteout conditions and heavy snow, but one thing seems to be missing: extreme cold! Overall temperatures have been fairly mild (by our standards) since December, with our coldest temperatures actually occurring before the winter officially started in November at -26°F on the 22nd. December saw an average temperature of 11°F, slightly above average, and only saw -12°F as our coldest temperature to start the real winter season, pretty benign!
Last winter saw some record setting cold and warmth, but overall was a little more on the warm side. Just over a year ago on January 6th, 2018 we hit a new daily record low of -38°F, the coldest in my 6 years on the summit also. February was quiet the opposite, with a winter season record high of 48°F, t-shirt weather! Although it was cool to say I wore a t-shirt in the middle of the winter on the summit I'd really prefer more of the cold and snow we're known for.
Record setting warmth February 21st, 2018
There looks to be some big changes on the horizon, however. After seeing a pretty big storm system the past several days carve out a new upper level trough it seems the pattern of having mild air across the East is coming to an end for now. Temperatures climbed to near freezing just ahead of the storm on the 8th and 9th, but now we’re approaching 0°F (with 13” of new snow and counting!). Much colder air will continue to pour into New England tonight and through the weekend, with temperatures likely bottoming out around -15°F sometime Saturday night. Winds will also be impressive during this time frame, potentially exceeding 120 mph, with wind chill values approaching -65°F.
This weekend may just be the “appetizer” for an even more impressive cold snap during the middle to late part of next week. An arctic cold front looks set to cross New England sometime Tuesday night through Thursday morning, with potentially the coldest air of this winter so far. Very cold air looks to be locked in place over Northeast Canada, and depending on the strength of the clipper/arctic front some of this frigid air may spill into northern New England by Thursday. This morning’s GFS model so far is the coldest, and would bring readings of near -30°F to the summit if it verifies. While I’m not always a huge fan of bitter cold, this would be another thing to check off the list so far this winter, and we always enjoy our extremes up here!
GFS Model 850 mb temperatures (roughly 5k feet asl) showing sub-zero readings across the Northeast Thursday morning. Image courtesy of Tropical Tidbits.
Tom Padham, Weather Observer/Education Specialist