Good Sunday everyone :-)
I hope you all remembered to set your clocks ahead one hour. I know I'm going to fight to not be late for church-- and I'm normally up at 1am!
So we keep watching the evolution of our storm system out west. We've talked about the 'bowling ball' nature of its mid-level support a few days back, and have been contrasting how it appears on various models. Another way that meteorologists follow storms is by tracking how they have been modeled by the same model over the past few days previous. Each computer model has its own way of modeling the physics of the atmosphere, and also has its own grid-surface rendering of the terrain (an equally important part of the forecast). The more data a model is given, the more time it takes to be run, despite some of the most powerful supercomputers in the world on the task. As a result, some models are tailored to go out a longer range, but with slightly less resolution of the terrain, or less variables in the product, etc. The models I happen to like the most for accuracy only go out 84-hours from the initialization time (the snapshot of the world it's given at 0-hour is called the 'initialization'). So what I'm going to show you is how Monday's rain (again starting at 2-pm Monday) has been modeled for the past 2 days-- with two days to go (on this particular model). There are more recent model runs since this one was issued, but I want these data points to digest specifically.
So the animation I'm going to show you is called the 'model creep'. This is the NAM model's representation of Monday - 2pm weather across various runs from two days ago through now:
|NAM - 2PM - Monday|
As you can see in the animation, the model has been handling the High pressure system off the Carolina coast fairly consistently, and to a large extent the actual center of the Low pressure system on the western side of Lake Superior. The preciptation plume around the Low is fairly well similar across the runs, but clearly the trailing cold-front is not uniformly placed. The reason for this is that it's actually a combination of warm air advection from the Gulf of Mexico meeting an only modest impression of mid-level vorticity support located to the north/west (it's a clash of moderate air masses instead of a strong sweeping front). Nevertheless, in the recent frames, there does appear to be an indication that the showers are going to make it into town perhaps earlier than 2pm, and may even do so with some thunder (we're getting to the point where thunder is simply going to be in the mix with any rain opportunity, though it's technically not even spring yet).
So as this meeting of moisture and forcing generates showers and storms today, let's keep an eye on things. Here's some tracking tools for you. :-)
|Regional Radar/Satellite with Warnings Tracking|
From the Storm Prediction Center (below): Click For a Larger Image
|Activity Overview||Storm Outlook||Watches||Potential Watches||Storm Reports|
|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!