The models are suggesting that we are going to be dealing with a Miller B type solution with an inverted trough extending back towards the region. Inverted troughs are very difficult to pinpoint to begin with as they are a narrow band of heavier precipitation & where that sets up determines whom gets the heaviest amounts.
For those that do not know what an inverted trough is, here is the definition…
In the mid-latitudes of the Northern Hemisphere a trough is usually seen as a southerly bulge in the height contours. The lowest heights are generally located to the north of the trough. In an inverted trough situation, the height contours bulge to the north. This is more common in the tropical regions where regions of low pressure ride south of a mid-latitude high pressure but can happen in the mid-latitudes when low pressure is south of high pressure. An inverted trough bulges to the north. At first it may look like a ridge, but on further inspection it is a trough. Both a trough and an inverted trough have a cyclonic (counterclockwise) flow pattern. A trough will tend to have more westerly winds associated with it while an inverted trough will tend to have more easterly winds associated with it. If an inverted trough is actually a ridge then the winds will be flowing with the height contours in the opposite direction (anti-cyclonic direction). The direction of windflow through the feature is how a ridge is discerned from an inverted trough.
However..before we even think about the inverted trough feature we have to look at the latest guidance and see if it makes sense.
We see at 72 hrs on the GFS a low pops just south of Long Island..but at the same time we see a Maxima precipitation area marked by an “X” right off of Hatteras. When looking at the image that suggests that there should be an area of low pressure at that location. And we see this is indeed the case when we look at the next frame of 78 hrs.
Now..we see that the area of low pressure at 78 hrs has indeed arisen from the area that was off of Hatteras & then of course..what happened to the secondary that popped south of Long Island? It is no longer there! My suggestion is it should NOT have been there to start with.
Now lets look at one other piece of guidance and this is the model with the most progressive Southeast bias when it comes to coastal lows & this has also been the most consistent model with moving this system towards the west and this model takes a 968 mb low to the benchmark!
So this suggests that the GFS/ECM/GGEM/UKMET are too far to the east. This is almost exactly what these models did with the last system that ended up being a blizzard for PHL to NYC into NJ and NE of NYC.
Keep in mind that this is a Northern Stream system. Keep in mind that the ECM has already shown 1 model run that delivered and east coast blizzard. The only difference this time around is that the other models have yet to show a blizzard for the Mid Atlantic to the NE. However, its important to keep in mind that the models did not realize the error to the east was an error until we were under 36 hrs.
Another important thing to keep in mind is that the secondary should want to develop along the greatest thermal gradient. This fact alone would suggest that the secondary should develop closer to the coast along the western side of the Gulf Stream which is climatologically favored.
Now, I am not suggesting that this could be a blizzard…but i am suggesting that this has the potential to come further west with the above information and be more of a big deal then what it currently appears.
For now..we have created a Preliminary map going with the inverted trough idea and not so much the coastal..
Keep in mind that this is preliminary and based on just the inverted trough..if modeling should suddenly pick up on the thoughts above ..then we would have to change the current thinking and issue another map. The above map has high bust potential as well cause any systems with inverted troughs are difficult to pinpoint from this range. However, a blend of the ensemble means was used for the map above!
Stay tuned as we will continue to monitor this time period and adjust when needed!
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