This graphic highlights any tropical depressions, storms, or hurricanes that the NHC is issuing advisories on as well as invests or other weather systems discussed in the Tropical Weather Outlook (TWO) and the Tropical Weather Discussion.
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Total Precipitable Water
This graphic shows the GFS forecast for sea level pressure and wind vectors out to 48 hours
NHC 24 hour surface forecast showing sea level pressure, tropical waves, and current systems.
Surge Exceedance / Surge Probabilities
NHC Experimental Marine Graphicast
Wind Shear Analysis
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Wind shear is a change in wind velocity (speed and/or direction) with height. Shear can rip a tropical cyclone apart or keep one from forming by preventing the convection from building. The following images show the latest wind shear and the shear tendency – whether it is increasing or decreasing.
This chart represents the 24-hour change in wind shear (shear tendency).
Upper level divergence is when the air in the upper levels of the atmosphere is moving away from a common area. It can induce sustained updrafts and therefore provide the exhaust system for a tropical cyclone, allowing it to strengthen.
Lower level convergence is when the air in the lower levels of the atmosphere is coming together in a relatively small area – the opposite of divergence. Eventually, there is nowhere for the air to go but up.
The steering winds in the atmosphere can help us determine the path and speed of a tropical cyclone. One rule of thumb says that the cyclone will move in the direction of the steering currents, but at about half the speed. However, the steering layer we need to look at is based on how deep the tropical cyclone is. We can determine this from the minimum pressure and then use the appropriate image below.