January 27-28, 2019 | Clipper Winter Storm
Recommended
Okay @UTSwiiniiso I see I was summoned about the Jax rule. I did a bit more research so that I could more properly explain everything to the board. To understand the rule, first we have to understand how cyclogenesis works. As a quick refresher, this is how it works. So you need a temp gradient, also known as a baroclynic zone. From here, what happens is physics begins to take over to convert potential energy into kinetic energy. It does so through the processes associated with the temperature gradient. Therefore what happens is you have a front transverse the region. On this front to the left, or West you have hot air, and to the right - East- you have cool air. As we all know, heat rises and cold air sinks. As this happens the storm begins to orient itself zonally, or from west to east. From here the Coriolis effect takes place and you start to see the spin of a low pressure system. This is the basic form of cyclogenesis.
As the cyclogenesis begins to take shape, you begin to see thunderstorms develop in the warm sector. What this does is to allow for latent heat to be released through the heavy precipitation that accompany thunderstorms. Latent heat is released best through moisture and condensation, therefore it is best released in the lower troposphere. What begins to happen is this latent heat release transfers into the upper atmosphere and allows for Divergence in the upper atmosphere. As a refresher, Divergence is when air evacuates an air column. Because of this, a developing low pressure system can begin to intensify more quickly. Consequently, this allows the original zonal orientation of the low pressure system or in other words the west to east movement, to become more poleward in motion. In other words, this means that the storm moves more south to North then west to east. Therefore, what this means is that when LP are going out to sea and you begin to observe a plethora of convection in the Jacksonville, Florida region, there's a good chance that this LP is going to bend Northwest instead of going out to sea and ride up the coast. Furthermore, this latent heat release allows for a stronger low pressure system as we already have talked about the Divergence caused Downstream. Therefore, the Jax rule can safely correlate to a stronger and closest system to the coast for the Mid-Atlantic and Northeast region.
As a side note, this also helps me understand why I made such an error in my last forecast with the last storm. I use this as an illustration. What happened is the storm began to strengthen more quickly than expected. As the storm strengthened more quickly, it caused more convection in the warm sector. This, in turn, led the west to east orientation of the baroclynic Zone becoming more south to North. This is why you saw the storm reaching for Virginia and the Delmarva region only to quickly scoot over New Jersey, up to Long Island and into the Northeast. The storm strengthened about 150 miles west of Jacksonville Florida. Taking this correlation and moving it West there for allows you to see why the storm went to New Jersey instead of off the Eastern seaboard
If you want to learn, read this post!
Recommended by Phased Vort
Recommended
Ensemble sensitivity indicates that the models will likely suffer significant run to run variation.
This is based off a combination of GFS+CMC ensembles.
Nearly half of the variance is explained by models placing a low INVOF of OBX.
the differences can mostly be traced back to energy diving down from the arctic. The way you read these, if actual heights end up higher in the warm colors and lower in the cool colors, EOF 1 (low near OBX) is more likely to verify.
As I mentioned above, significant differences don't show up for a few days, hence my reasoning for poor run to run consistency, so any "trends" at this stage could be phantom.
http://breezy.somas.stonybrook.edu/CSTAR/Ensemble_Sensitivity/EnSense_Main.html
Good analysis of ensemble quidance.
Recommended by Phased Vort
Recommended
Most models on recent runs have been keeping this possible storm out to sea.
What I believe needs to change on future runs is where the cold front that swings by the region on the Jan 24-25th time frames stalls. It looks like most models have been stalling that cold front near Bermuda, which as result, sets up the baroclinic zone near Bermuda as well or just the west of it. That baroclinic zone, where the most intense temperature gradient is found, along with the stalled out cold front, acts like a train track for the storm´s low-pressure center to develop keeping in mind that stalled out fronts create areas of lower pressures, which is usually where low-pressure systems tend to develop.
Hence, what needs to change in my humble opinion, is where the cold front stalls. On future runs, we need to see that cold front stall more the NW away from Bermuda, so that area of lower pressure and the baroclinic zone sets up closer to the US eastern seaboard. That way the low-pressure center or energy, if you will, tracks close enough to the coast so that moisture being lifted to create the storm´s precipitation shield, can actually be thrown into the cold air over the east coast and this way the region get an impactful storm for this time frame.
Black arrow - Low pressure track
Dashed pink line - Stalled out cold front
Gray arrows - High pressure and low-pressure flow
The black arrow curvature on both images away from the stalled front and the baroclinic zone is due to the storm becoming deeper (stronger) as it is enthused with vorticity energy from the Great Lakes region and/or the Canadian Maritimes.
Another thing I have noticed is that we run the risk of either having only one storm within the Jan 27th - Feb 1st time frame. I say that because if the track for the storm for this thread tracks more offshore in case the cold front in discussion stalls farther offshore near Bermuda, the region would not be impacted much or if at all by this storm, and then possibly only the storm for Jan 30th -Feb 1st time frame would actually hit the region. OR, in the case, the timing is good and there´s a more coordinated interaction between the storm for this thread and the energy from the northern stream diving SE´ward from the western Great Lakes region, there would be some kind of phasing, and that way probably only the storm for this thread would occur.
Let´s see how that cold front acts and its speed as it relates to the cyclogenesis supposed to occur over the GOMEX or Florida for this storm since I believe it to be pivotal concerning how I see the situation now.
A must read
Recommended by MaineJay
-
Recently Browsing 0 members
No registered users viewing this page.