Could A Superstorm Occur In The Next 7 Days???
Tonight I am going to write a more technical blog than I normally do when the weather is quiet. Many times, I write the more technical blogs during severe weather, but tonight offers a unique opportunity as some data suggests a Superstorm could occur over the next 7 day in the US.
What Is A Superstorm?
Superstorms are anomolously powerful low pressure systems that form when unique conditions occur with perfect timing creating a monster. An example of a Superstorm is the 1993 blizzard that produced tornadoes on the Gulf Of Mexico and over 40" of snow from North Carolina through the northeast. Another Superstorm was the infamous "Perfect Storm" that phased hurricane Grace and a powerful low pressure in the mid latitudes to create a monster storm. The pressure on "The Perfect Storm" was 972 mb. The wave heights off shore during The Perfect Storm were over 100 feet!
These weather freak shows are very unique and don't occur very often because such unique conditions must phase at exactly the perfect time. True Superstorms are really once in 25 year (or so) events.
Could The Conditions Be Ideal For A Superstorm?
First let's look at the latest conditions and if the ingredients suggest this could really happen in the next 7 days. The tropical system we are talking about is Sandy. Sandy is forecast to become a hurricane in the next 24 hours and strike Jamaica as a hurricane.
As this storm moves toward toward the northeast, there are many questions about what it will do as it gets to a latitude near Bermuda. The GFS takes this storm harmlessly out to see and the EURO brings a titanic storm into the northeast.
GFS Forecast Next Tuesday
Notice the storm moving harmlessly out to sea.
EURO Forecast Next Tuesday
Notice the EURO bends this storm back toward the US as a Superstorm with a central pressure near 944 mb. 944 mb is basically the pressure of a category 3 hurricane would be an extraordinary Superstorm. It would be a once in a life-time event.
Looking deeper into the data, we see a number of the computer models are split into two camps... those that move the storm harmlessly out to sea and those that create a Superstorm. Notice the gray lines all take this storm into the northeast US.
Could the Superstorm solution be reliable?
Let's Break Down The Weather Pattern
Superstorms are truely rare anomolies in the atmosphere. We must have a mechanism that forces energy from either two jet streams together or combine tropical and mid latitude energy. Many times you hear meteorologists say "XXX computer model is saying this, but YYY computer model is saying something completely different and we will just have to wait and see". The trouble with that style of forecasting is you never involve meteorology in that equation. We must know why the EURO is moving that storm toward the US after it goes past Bermuda and if that solution is possible. What we know right now is that there is a "Omega or REX block" occurring over the north Atlantic. You can see that image of the greek letter omega... Ω ... over the north Atlantic right now. Follow the black lines I drew on this image...
Why is an Omega / REX block occurring over the North Atlantic becomes our next question if we are truly to understand the weather pattern and evaluate the EURO computer model solution! Currently we have a NAO (North Atlantic Oscillation) that is negative phase and this piece of data is critical. A negative NAO prefers blocking patterns over the north Atlantic and it should be no surprise to see one there now. As we start to move forward to the possible genesis of a Superstorm, we are now armed with some more info to help us evaluate the EURO solution. As Sandy moves toward the Northeast US, it "kicks" the low out of the southwest side of the Omega / REX block.
Once that low departs, the Omega / REX block naturally looks for a low to replace the departing low pressure. Since we know the negative NAO prefers blocking patterns, we see the EURO pick up on this and deposit Sandy into the southwest slot of the Omega / REX block. Notice the appearance once again of the greek letter Omega... Ω ...in the jet stream winds by next Tuesday.
This means the EURO solution is not a freak anomoly, but a truly viable solution and realistic solution.
My Thoughts On A Potential Superstorm In The Northeast US
The beginning of an accurate forecast is understanding why the computer model is producing it's forecast. What we have learned through this discussion is that a negative NAO prefers a blocking pattern and an Omega / REX block is exactly what we would expect to see in this scenario. This explains why a tropical system would oddly move toward the northwest or west when we expect storms to always go from west to east. Sandy would enter into the southwest part of the Omega / REX and be energized by the mid latitude jetstream winds creating a Superstorm in the northeast.
I would be lying if I said a Superstorm was guaranteed to happen because we are still talking about a storm that is in the Carribean sea. We know tropical systems can be erratic when they are slow movers which is the exact scenario we have right now. The storm would need to get to near Bermuda by around Sunday morning for this to happen. I think that appears to be a reasonable forecast right now. If that happens, a sequence of events could occur to create this Superstorm. Sandy would then kick the low pressure on the southwest side of the Omega/REX block to the north and allow Sandy to merge with the storm bringing our front in on Friday. As this merger occurs, a Superstorm could form. The blocking Omega / REX would then force the storm west into the northeast US as a major storm. If all these events fall into place, we could be talking about a monster Superstorm in the northeast with flooding rains, major coastal flooding, significant beach errosion, and widespread power outages in the northeast. When you consider "The Perfect Storm" was 972 mb and the EURO shows this storm as a 944 mb low, you get the idea of the potential here. Remember "The Perfect Storm" produced 100 foot waves in the open sea and the EURO suggests this will be considerably stronger!
If the tropical system wasn't in the Carribean and so far away right now, I would say the EURO Superstorm solution is most likely. The reality is we are still talking about potential, but it is interesting when you evaluate and tear apart the EURO solution to test if it makes sense from a scientific standpoint. This is something I will be blogging about and watching closely in the coming days.
For Kentuckiana, this would only mean breezy conditions and I am taking this storm into account when I forecasted highs in the 50s next week.
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