Regarding the severity of the Superstorm, the point was raised that if the looming disaster is a simple storm, a well trained Pegasus team should be able to dispatch it. I wanted to test the veracity of this idea, so I watched Hurricane Fluttershy again in an effort to see if I could make sense of the weather, or it's just a bunch of nonsense the writers threw together for the episode.

Well, believe it or not, while I did have to make a small amount of assumptions, the math holds up. I am as surprised as you are. I'll do my best to present the information in the simplest and most efficient way, but if you so desire, I'll share the exact calculations I used to arrive at these conclusions. So let's begin, shall we?

The first thing to do is determine how strong Pegasus ponies are in relation to weather phenomena. Thankfully, Hurricane Fluttershy gives us a clear cut explanation.

To refresh your memory, the episode deals with the Pegasus of Ponyville having to create a tornado to send water from their reservoir to Cloudsdale so they can create clouds for all of Equestria. The episode also provides us with enough information to determine how this works.

We are told that in order to lift the water, the tornado created must have a minimum of 800 wing power.

Let's fast forward until the end of the episode, where eight Pegasus have fallen victim to the feather-flu, leaving them with less than enough wingpower to reach the desired eight hundred.

Based on this, I calculated that there must have been a total of 39 Pegasus flying in the tornado with an absolute top force of 25.6 wingpower (From now on referred as WnPw) in average at the peak of the tornado.

That means that an average Pegasus with a few weeks of training can reach an average top force of 25.6 WnPW

Now that we've determined the top speed an average Pegasus after intense training can reach at their peak, we must determine how strong the tornado they formed was.

Here I posit that what the Pegasus of Ponyville formed wasn't a simple tornado, but rather a type of waterspout. Here's my basis: When tornadoes form over water and present a column of water in their vortex, they're called waterspouts. Waterspouts are weaker than tornadoes, but still strong enough to mantain a constant flow of water, as seen in the episode.

Now, you may be wondering why it had to be a waterspout and not a normal tornado. Here's why:

When the group of Pegasus sans Fluttershy peak at 795 WnPW, they are barely managing to make the water lift before breaking apart, so it couldn't have been a stronger tornado. So I'm being generous and I will take that 800 WnPW is the bare minimum needed to form a waterspout, wich has top speeds of approximatedly 30 m/s (67mph for you imperialists)

Now, thanks to this first analysis and calculation, we can safely say that:

Having established this, it would make sense to think that the amount of force needed to form and mantain a tornado (or waterspout) should be the same amount of force needed to make it dissipate. Now, let's apply this to the windspeed of hurricanes, as dictated by the Saffir–Simpson hurricane wind scale:

I should note that Category 5 Hurricanes are categorised as any hurricane with windspeeds above 70 m/s. For the sake of having a numeric value assigned to it, I gave it the same windspeeds as the strongest windspeeds for an F4 tornado.

Now that we have the total wing power needed to dispell each tornado, we only have to make a quick division to find out how many pegasus would be needed to dissipate a hurricane, if we take the absolute peak reached by the Pegasus of Ponyville, meaning 25.6 WnPw, we get these results:

We finally reach a concrete number. However there is one final issue we must take into account.

Let's take another look at the waterspout created in Hurricane Fluttershy.

First of all, take a look at where the waterspout was formed:

We can see that they are away from Ponyville, and the reservoir is surrounded by hills, meaning that not only are they away from any debris, but they are somewhat isolated from wind currents. Also notice the clear skies. These are ideal conditions for weather manipulation, which is probably why that day and place were chosen.

Imagine the conditions of a hurricane. Flying debris, heavy rain, falling temperatures. All are factors that must be taken into account.

But all these are external factors, we are yet to analyse the most important one:

The Pegasus are showing clear signs of strain. And that's only at 500 WnPw, meaning that each of them is going at an average speed of 12.82 WnPw, and they're yelling to be heard.

Now that we have all this data, let's make some conclusions.

What can we gather from Hurricane Fluttershy?

That a group of 39 trained Pegasus, flying with a force of 12.82 WnPw, under ideal conditions, were able to reach a total of 500 WnPw. Which means that when they all managed to reach 795 WnPw before Fluttershy's intervention, they really were giving it their all.

Following this data, we can conclude that, under ideal conditions, a group of 61 highly-trained Pegasus, specialised in weather, flying with a wing-breaking force of 25.6 WnPw would barely be able to disippate a Category 3 Hurricane.

However. If we take in consideration all the other factors, that number would have to increase.

So, let's make one final calculation. And this time, let's give our weather team a more realistic flying speed, considering they would have to pace themselves to properly to not strain their bodies and pass out in exhaustion. Let's say they fly with 16.5 WnPw, the speed Rainbow Dash reached before training. And let's add a contingency amount of Pegasus (in this case 10% more). And I'll keep it simple this time.

I'll stop here and for a reason. As you can see, the more factors you take into account, the bigger the numbers get. And this presents another problem, a problem even bigger than flying debris, rain, and cold temperature.

As I said earlier, when the Pegasus are forming the waterspout and are about to reach 800 WnPw, they have to yell to hear each other. And those are winds with an absotute top speed of 30 m/s. As the speed doubles and even triples for hurricanes of higher categories, it would become much more difficult if not outright impossible for the Pegasus to comunicate with each other.

And when you're trying to fly in the middle of a hurricane, you need to be able to communicate the smallest change in air currents or it could spell doom for your partners.

Therefore, let's answer the question of whether or not would a team of Pegasus be able to dissipate a large hurricane.

The answer is a clear no.

After all, we have just made a measure of pure force, we would also have to consider that the pegasus would have to spread over all the area of a hurricane, which can be hundreds of kilometers wide. All of these would severly impede comunication and visibility, which would lead to an even bigger disaster, and in the worst case scenario, even a few casualties.

So, yeah. The storm doesn't actually need magic. An ordinary hurricane would wreck even the best weather Ponies Equestria has to offer.

5036416
Wow, that is a lot of calculation. I have a question though, how many pegasi would it need to dissipate a superstorm? I bet it would be a lot.

I think that you should also take into account the heat generation of such a large amount of individuals. So many pegasi giving their all would be a furnance, not to mention the water contribution of their bodily fluids -mainly sweat- and the mass added by, well, the bodies, both alive and not[1].
Ten humans are already a ton, we can guess a pegasi is lighter so lets say that eight pegasi are a ton, but lets take into account the gear they'd need, which for flying creatures that need to fly fast one can estimate around twenty kilograms, so lets say that twelve military pegasi are a ton. So 125 pegasi=10~ tons.
Last, one has to take into account than in most taskforces, the amount of people sent is [Strictly necesary amount]+%10(Extra amount to be sure)+%25(In case someone gets hurt and has to be replaced), so the actual team sent would be of 172 pegasi (Well, 171.817, but fractions of soldier usualy travel in a casket), so we have 14 tons of pegasi added. You don't want to add 14 tons to an hurricane[2], especially when bodies start flying out of it and falling in ceilings a country away, lowering morale to negative numbers. And we still haven't worked in the sweat heat/humidity they'd add.
So: sending them in isn't a good idea in any shape or form. Sending bodies of cold air sound like the best option here.
EDIT: I just noticed the mistake with the pegasus weight ratio (It was suposed to be twelve-eight, but got it wrong and just kind of kept rolling with the reversed ones) but still , my argument applies. Not only would it be unfeasible, but they'd likely worsen the situation.
EDIT 2:And I just saw that you had already added a %10, but still my argument applies for realsies.

[1]: It isn't a situation to take care of bodies that ain't working anymore, I should add, especially when said body is going quickly enough to rip off your arms when you grab it
[2]: Poor communication = Reinforcements can't be called = Everyone has to go in.

Don't forget there's also size to consider. A tornado is much smaller (a few square miles if you include the hook echo) and more compact than a hurricane (hundreds or thousands of square miles).

5036583

As akel said, the sheer size of the storm would make dispelling it extremely difficult. The pegasi were already struggling to build up a small tornado, so imagine that but with a 500km radius hurricane.

I've got a bit of experience in meteorology from my glider courses, and sending cold air or a high pressure to stop or diminish the hurricane would be an easier, safer and more effective way than brute force.

What I think would happen is weather control doing the same, weakening the storm as much as possible and wait for it to pass, before whatever magibabble makes it go inland.

5036889
Yea that makes sense, a superstorm of that size wouldn't be toppled easily.

5036686
I intentionally wanted to analyse solely the force needed to disippate the Hurricanes, because the more factors you take into consideration, then the higher the number must be. So, for the sake of the argument I made things as simple as possible.

And I do mention the issue of communication in the conclusions. Ponies flying in a tornado of the lowest speed possible had to yell to be able to hear each other, and they were relatively close.

If you were to do the same in a hurricane, even if it's just in the eye of the hurricane, it wouldn't be possible to talk to each other, jeopardizing the whole mission.

5036782

I do mention it briefly in the conclusions. If it was hard for the Pegasus to talk to each other in a low speed tornado, where the distance from one another wasn't too big, then trying to do the same in a hurricane, even just the eye, would be next to impossible.

5036889

What I think would happen is weather control doing the same, weakening the storm as much as possible and wait for it to pass, before whatever magibabble makes it go inland.

I think this would be the most sensible approach.

We already know Pegasus wouldn't be able to dissipate a hurricane, so it makes sense if they tried to mitigate it, or at least try to control its path...

...Only for it to kick 'em in the face and veer inland.