Wirelessly posted (Samsung Galaxy S: Mozilla/5.0 (Linux; U; Android 2.3.6; en-us; SGH-T959V Build/GINGERBREAD) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1)
Finite elements calculations for CFD, complex structures, weather, etc require lots of calculations. If you took a portion of the atmosphere 20 km above the surface of the earth and divided into a trillion cells for your calculations, each cell would be a sqaure, one seventh of a mile. Accuracy of the calculations depend om the grid size. You have to make the grids smaller for better accuracy. Eaxh cell will be governed by diffetential equations and boundary conditions. The computational effort goes up as cube of the number of cells. A trillion cells model requires at least ten raised to the power thirty six calculations. By contrast deciphering a 128 bit code requires ten to tje thirty three calculations, if you have absolutely no clue. This effort is a thousand times smaller than a atrillion cell grid. If you reduce the cell size to a litlle smaller than half the original size, you increase the number of cells to ten trillion cells and the compuyational effort to ten to the 39th power, already a million times the effort of brealing a 128 bit code blind.
Your claim does not appear to be based on any reasoning, just a belief arisiing from the awe and respect for these agencies and their need for secrecy.
I can only speak for and of what I know and can reason. Hollywood may create a different impression.