It's back to Monday for everyone...
Today will feature a mix of clouds and sunshine, and a small system streaming in and out. Scattered showers will be found overhead, but the main take-aways will be the last bit of the milder temperatures and the onslaught of haven't-seen-in-a-while colder air riding in (we've been talking about this one for quite a bit of time actually).
Here's an animation of how it looks with warm fronts, cold fronts, and such...also known as the 'surface map':
A couple of interesting features on this map. First, notice the deep plunging cold front that begins at the Ohio Valley but manages to push its way down to the Gulf of Mexico by the end of the loop (Wednesday). That's definitely a more normal early spring thing compared to the huge summer-time ridge that we've seen more than a couple of times since early March. The other thing that I want to point out is that there is a general area of low pressure concentrated over Maine and southeastern Canada throughout the entire period. Doesn't it look like waves of energy are simply pivoting around it like a pinwheel? Well...they are. And that process has a name; it's called the "Fujiwhara" Effect. It's certainly a very wonky weather geeky kind of term, so I've linked it to its wikipedia entry. It's typically associated with hurricane movements, but it also works for situations like this, and will actually be one of the main reasons why we'll be able to link up unseasonable cold with moisture to get flakes into the mountains.
Here's a look at how those temperatures are going to go, relative to normal, for the next few days ahead:
|GFS - Temp Anomaly - Monday||GFS - Temp Anomaly - Tuesday||GFS - Temp Anomaly - Wednesday|
So after another decent temperature day today, the bottom will fall out and we'll get to 10-15 degrees below normal by mid-week. Surprisingly, this has held much in line with what we were first looking at with this system almost a week ago. That sort of in-advance verification usually only happens with strong systems in the winter-time, and even then only about 10-20% of the time they show up (because they just about always show up in the winter if you go out far enough on a computer model) ;-)
---Wonky Weather-Geeky Tangent (skip ahead if uninterested)---
So this stuff may again be a little confusing, or 'out there', but bear with me, and feel free to ask questions in the comments section for me to address if I can get to them today.
I wanted to put up some 'vorticity' maps with this coming storm, to give you an idea of what is happening in the middle levels of the atmosphere to bring about our big changing weather pattern. First, a wide-view:
|GFS - Vorticity - Monday PM
||GFS - Temperature (850mb) - Monday PM|
On the first map I've drawn in some yellow circles and arrows to indicate important features and their anticipated direction of movement. As discussed before, 'vorticity' is a term for the spinning energy in the atmosphere partially generated by the mere rotation of the Earth, and partially generated from storm systems that are swirling about. Wherever the big pushes of vorticity go, so does all the storm energy. In this particular scenario, there are two arms of vorticity more-or-less heading toward the same place. (Vorticity is an additive property, so two or more blobs of it can phase together at will and create something even bigger, etc.) One is going to bring the cold, and the other the moisture. If you look at the right-hand map, this shows temperatures at the 850-milibar pressure level (which is usually around 5000 feet in the air, say the lower cloud level). The left-hand vorticity blob is associated with temperatures of -10°C air (that's cold) and the right hand one is associated with the precipitation. We meteorologists cross-reference a whole ton of maps during the course of making a forecast, if you can't tell ;-)
Anyway, I wanted to string together one more animation that shows a little higher resolution closer-up to give you an idea of how this push is going to affect our weather locally:
|WRF - Vorticity||WRF - Precipitation Type|
So let's not get crazy now with the maps ;-) All I want you to see here is that the vorticity pushing south across the Great Lakes, together with the simultaneously arriving colder air, will be sufficient to get the flakes flying even though we've seen plenty of days in the 80s in the last 30-days. Nature is still quite capable of bringing 'normal' April weather in April no matter what happened in March.
---End Wonky Tangent---
I personally don't like to go out and issue anticipated snowfall forecasts for out-of-the-ordinary events like this, because of how things will change before we even get to when it happens. At this point, it's the mere fact of flakes in the air for the mountains that is interesting enough for me, and is where I would officially begin the conversation, and go from there. Nevertheless, since I think y'all have a particular flair for this sort of thing (and won't go overboard for what it truly means and doesn't mean), here's a map I like to look at that integrates a lot of good physics arcoss a decent terrain resolution:
|WRF - Snowfall Accumulation|
Remember, it's not the actuall accumulation amounts that is important (or serious), but it's the mere presence of accumulating snow that is what we're looking for at this juncture. Most of our local area will be getting scattered chilly showers and not flakes-- but perhaps we may sneak a few in if we get a nice breeze ;-)
But all that is in the future...today's not lookin so bad. So if you've got another day off, why not sit back and enjoy it.
|Regional Radar/Satellite with Warnings Tracking||
|Temperatures||HD Doppler Radar||Estimated Rainfall||Active Warnings|
|Click For Larger||Click For Interactive Radar||Click For Larger||Click For Larger|
Have a great day everyone!