Irene Struggling To Maintain Intensity

Increased shear, dry air, and upwelling all appear to be taking their toll on the hurricane. Many of the deeper/colder cloud tops have dissipated over the nighttime hours. This apparent weakening trend has been confirmed by hurricane hunter aircraft who have found an everly increasing pressure. Soon wind speeds will respond.

Satellite Picture Of Storm

There remain two important questions: 1) Will the weakening trend continue? 2) And where will Irene travel to?

Lets start off with the second question first. All of the more reliable computer models now never strike land and have this hurricane recurving out into the Atlantic Ocean. The computer models have a pretty good grasp on the storm and the synoptics. Don't be surprised if there is even yet another shift to the right. In fact, as I am writing this, the computer model that has always been on the left side of the model guidance (NAM model) is now coming in significantly right of its previous forecasts.

As for intensity, there appears to be lots of arc clouds on the western side of the circulation. This is clear evidence that the storm is being affected by shear and that the storm is declining, somewhat, in intensity. The SHIPS forecast model is evening forecasting increased shear around 20 knots, throughout the day.

Computer Models Of Irene's Strength

None of the computer models make this a category 5 hurricane and few even make the hurricane a category 4. In fact, the official forecast is even below category 4 strength. Do not be surprised if the storm does make it to be a major hurricane, which means will stay below 115 mph. Increasing shear ahead of numerous shortwaves and plentiful dry air is to blame for the suffocation of the storm.