Happy Tuesday morning everyone!
Hopefully you've been trying to get a little more acclimated to the cooler temperatures, particularly in the morning, because now it's about to change on you (doesn't it always happen that way?) Now, this morning's lows will be a tad warmer than yesterday's, but still putting out a few areas of patchy frost-- just not nearly to the same degree. Besides, for most folks, once you've had that first good fall frost, you're about done with growing things outside anyway.
High pressure has been responsible for our good weather fortune, but that ship has now sailed. Here's the picture of what's gathering to the west:
|HPC - Tuesday PM|
...Time for a change in the pattern. Now we're going to be in a persistent area of general low pressure. This puts us in line for scattered showers on an occasional basis throughout the next several days. I'd like to put up a few more maps to underscore the new pattern we're in.
|GFS - 700mb Chart - Relative Humidity - Midweek||GFS - 500mb Chart - Vorticity - Midweek
For those who don't frequent the blog too often, I should say that occasionally I'll be showing weather maps that I don't show on the air (this place is where I break down the weather in a little more technical format for those who crave a deeper understanding and/or a more weather-y experience... consider it the 'inside baseball' of forecasting). Despite what is normally seen on the air (the most readily understandable stuff), it's often the weather patterns in the upper levels of the atmosphere that dictate what goes for the forecast. So, case in point...
The left-hand map shows the concentration of humidity at about the 10,000 foot-mark (which would be right in the innards of typical cloud level of clouds that bring rain/snow/etc.) ... What I wanted to indicate to you is the convergence zone that is created by the windflow in the north and south parts of the US, right into the Ohio Valley. Notice how all the moisture ends up bunching up into the middle, leaving the outside areas dry by comparison. Hold onto that thought :-)
The right-hand map looks at what's called "Vorticity". This is a twisting in the atmosphere that first kicks off because the Earth is rotating, but since it 'has been rotating' for quite some time now we can factor out the influence of the spinning earth and instead focus on the little bundles of twisting energy that remain. In the case of a strong storm system, you would see a large bulge of red on the map, indicating the juice is loose... but that's not what we've got here. What we see in the mid-levels of the atmosphere are a bunch of disconnecting little piddly things.
Bringing the two thoughts together, expect to see more-or-less a stationary convergence zone right in our neighborhood that focuses occasional ripples of scattered showers. There will be an opportunity for rumbles of thunder in there too, but that is balanced by sunshine breaking out in between events. This weather-guy has an expression for this weather pattern:
It will never quite develop into a rainy day, nor ever get sunny and bright for too long. By the time it's all said and done, here's the anticipated rainfall:
|HPC - Total Rainfall Projection - Ending Saturday|
Don't let the rain amount scare you, this will not be a straight drizzle-fest occupying the rest of the week, but I doubt we'll get more than 12-hours of freedom in between rain events. These maps all jive pretty well together, as there will be a deficit of rainfall in the deep south and in the upper midwest while all the moisture pools into the Ohio Valley.
|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!