First, I just want to mention that this mornings low temperature hit 56 degrees. Another gorgeous day also!...Now onto more important issues, and if your not Meteorologically(Is this even a word) savvy, this post may not be for you.
There is a cool-season like low pressure system that is developing across the southeast bringing widespreads with it to MS,AL, and GA. Forecast models are predicting this low pressure to move south of central NC and off the coast on Wednesday. With this will come increased mid and upper level moisture as well as the chance for rain. Forecast models are predicting widespread 2-4 inch rain amounts across parts of GA,SC, and coastal NC. Areas further north are forecast to receive much less in the range just a trace to .50 with higher amounts in spots. There is a stationary boundary draped across SC and GA as well and it appears that the low will track across wherever this boundary lies. Heres the problem.. this is summertime.. why wouldnt the boundary start to move north once the warm air advection off the coast kicks in overnight. In the wintertime, stalled out boundaries to the south have a very hard time moving northward and a Cold Air Damming event sets up where warm air overrides the cool (or cold) air at the surface. A situation like this may occur tomorrow if precipitation begins to fall into the relatively dry air we have right now at the surface. But is it really going to stop the boundary from moving further north than staying over the coast? Something just does not make sense to me with the scenarios the models show. I realize there is a large vortex over the NE part of North America but its also retreating further north now also.
I learned last year that sometimes model over develop precipitation bulleyes forcing other issues to occur in its grids allowing for misplaced features. Could this be happening? One short-term model that has better resolution(NAM) does have some of these features moving further north than the model that does not have better resolution (GFS) but which will be right?? Normally CAD events have surface pressures 1025mb or higher... right now surface pressure are running 1010-1013 mb.. not that strong.. so that could also be a factor.
I guess what I am trying to say is that I am in no way confident that there will be these huge amounts confined to a region in GA,SC, and coastal NC. This could be totally wrong and be to high, or it can simply be correct and then we here in central and northern NC will not see much at all. I am no way confident in any of these scenarios and apart of me wants to believe there will be more significant rains across a larger area with this type of system. Oh and one more thing, the NAM is much slower with the progress of the low and its track than the GFS and this to me seems more reasonable as the flow right now in the jet stream is for slow progression.
Well thats that. we will see whos right. a computer or human knowledge of the meteorological setup. We will soon find out
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Good discussion. This storm has been fun to watch...I think the low track is a little over emphasized, however. What I mean by that is especially in this situation where it doesn't take much to get air to rise, precipitation can occur well away from the low. The NAM was the better of the two models indentifying the areas where sufficient lift would produce precip. The main mechanism was probably the upper level jet dynamics, but I think also we will see by a left over cloud deck that an in situ CAD setup (very weak but it doesn't take much) helped to bolster some piedmont precip. Unfortunately the areas that needed it most didn't get much at all.
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