Lets talk about weather computer models 101 and the theoretical Noreaster next Tuesday. If youre actually checking Facebook on a Friday night then youll appreciate our novel to help put you to sleep! This post is Freshman in college level geek speak so if you follow it - well make you an entry level meteorologist here at wt360. :) Fortunately my Air Force career propelled me out of this geek mode very early on back in the late 1980s but I digress. In simplest terms weather computer models are Physics/Fluid Dynamics based or the concept for every action, there is an equal and opposite reaction and the atmosphere is simply a moving fluid. If you threw one rock in a calm lake (think of the rock as a storm), youd get a perfectly symmetrical ripple in all directions - thats easy physics and easy to predict how fast and how strong those ripples would be. If our planet had just one storm and a flat Earth weather forecasting would be simple and nearly perfect. But in the real world we have big mountains, small mountains, big oceans, small lakes, warm oceans, cold oceans, snow here, ice there, big cities, forests, deserts and if the topography alone wasnt challenging enough for physics based models we have millions of little ripples in our atmosphere. So now imaging throwing a million rocks in the flat ocean and trying to predict all the interactions - MISSION IMPOSSIBLE...but thats what weather computer models attempt to figure out. But what if one rock was just a tad bigger than the model thought...that would impact all the other ripples (storms). What if one rock was thrown in the lake much faster than others, it would greatly impact all the other ripples. To make things even more complex, the atmosphere is not just a flat single surface it goes up 164,000+ feet which means now we need to not only predict the ripples on the surface but every little ripple above and below and how all those will interact with each other. At this point most college kids would say Im changing my major to history as there are just too many moving parts in Meteorology. ;) That said what does the model say...well theres another problem! We dont just have one weather model - that would make forecasting easy...we have many models (European, US GFS, Canadian, Japan, NAM, etc. etc. etc.) and all have strengths and weaknesses which we dont have time to discuss here. Weve highlighted some of the models here centered on next Tuesday when there MIGHT be a Noreaster. The challenge with this one is the El Nino like pattern were in which shows a split Jet Stream across the Southern U.S. and a northern branch across Canada. The storm that MIGHT create this Noreaster is currently 3 pieces of energy off California, Oregon and British Columbia. 2 pieces go North into Canada, one piece goes across the Deep South U.S. In theory theyll team back up along the East Coast next week. The question is do all three phase together to create one big Noreaster, do 2 pieces come together for a weaker warmer storm, do none of them ever get back together and the whole mess just moves into the Atlantic without ever coming together until they get up near the Canadian Maritimes??? Heres what the models say: Upper left is the model most meteorologists like which is the European Model since it predicted Sandy a couple years ago. It shows a strong Noreaster off Long Island Tuesday evening showing a heavy rain event from DC to Boston but changing to wet snow at the end. This clobbers Poconos to Central Maine with heavy snow. It also shows a little double loop around as it moves up from North Carolina which is highly unlikely so it by no means has everything figured out. We typically wont show the European model as many Facebook pages do as its a violation of the EURO policies to redistribute their forecasts and they are extremely strict on that. Model 2 in the upper right is the U.S. GFS which does not phase the 3 pieces of energy and keeps the northern branch as the main storm with a coastal low forming well off the East Coast and exploding once it gets up in the Canadian Maritimes. This means next to nothing for anyone other than New Hampshire - Maine. Much drier for big cities. Model 3 bottom left is the Canadian Model which is much faster than all the models by about 18 hours and much warmer and wet. Rain-Snow line would be Appalachian Mountains into Northern New England Mountains so all rain for everyone along the East Coast and well inland. Model 4 is the Japan Met Agency Model which has the Noreaster much broader storm and excessively wet which would be an epic blizzard for the Northeast. These models get new information 2 to 4 times a day so well have 10 to 20 more model runs so get ready for non-stop Modelologists interpretation of whats going to happen Tuesday-Wednesday. Since you read our novel well give you our 2 cents on what we think. Mostly rain from DC to Boston with some flurries on the back end. Heavy snow in the 6 to 12+ range from Central PA Appalachians into Binghamton NY area through the Adirondacks of NY into Green and White Mountains to Central Maine. Let’s see what models all say by Sunday evening before anyone starts planning their snopocalypse purchases of bread and milk. :) Thank you for reading our novel...youre now an honorary wt360 meteorologist...if you have a resume send it. :) Have a great night folks.
Posted on: Sat, 06 Dec 2014 01:50:29 +0000
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