Thursday, July 28, 2011

Tropical Storm Don Continues to Advance Toward Texas Coast...

At 7am CDT, the center of Tropical Storm Don was located about 545 miles East/Southeast of Corpus Christi, TX, and was moving toward the West/Northwest at 10 mph.  Maximum sustained winds were estimated at 40 mph, and the minimum central pressure was 29.53 inches of mercury.

As you can see by examining the satellite image of Don above, the system remains very compact, with little to no expansion in size having taken place in the last 24 hours.  While this is good news as it means that no rapid intensification has taken place in the last 12-18 hours, it also makes it difficult to predict how the intensity will change over the next 24-48 hours.  Smaller systems often fluctuate wildly in intensity, with rapid cycles of both intensification and weakening possible in a short period of time.

The computer forecast models are also having a difficult time resolving the future strength of the system, mainly for the same reason described above.  They are, however, continuing to show that the system will remain on a path to make landfall along the middle to lower Texas Coast on Friday night or early Saturday morning:

The National Hurricane Center (NHC) is currently forecasting landfall slightly to the left of the overall computer model projections, as shown on their latest forecast track image below:

Both the computer forecast models and the NHC forecast are indicating that the system will make landfall as a Tropical Storm, with maximum sustained winds of 55-60 mph currently forecast at the time of landfall.  As I mentioned a few paragraphs ago, a system of Don's size can fluctuate in intensity and/or  movement on short notice, so it is important for residents along the Texas coast to keep this in mind, as the forecast could change before landfall.

While the fact that Don is not currently undergoing any rapid intensification is good news as related to the overall potential for storm damage, it is bad news on the rainfall front.  Don't get me wrong, there will still be widespread heavy rainfall along the path of the system, but the fact that it has not grown in size means that the overall amount of "real estate" that will receive the most beneficial rain will remain relatively compact.  Below is the latest rainfall forecast for Saturday from the HPC:

Based on the current forecast path of Don, the most widespread and heaviest rainfall, on the order of 1.5 to 3 inches with locally higher amounts, will take place within the purple and reddish-orange shaded areas on the above image.  Scattered showers and thunderstorms producing lesser amounts of rainfall will take place to either side of this axis.  

The swath of heaviest, most widespread rainfall is highly dependent upon the exact track of Don both at landfall and about 12 hours afterward.  Keep in mind that this heavy rain forecast axis is likely to shift during the next day or so.  I'll keep updating the projection as the exact track of Don becomes more clear.

If you live along the middle to lower Texas Coast your Tropical Storm preparations should be completed today if at all possible.  Please review Tropical Storm and Hurricane Preparedness checklists, and make sure that you have a NOAA Weather Radio with battery back-up or some alternative means of receiving information available to you.

If you need a weather radio, I always highly recommend RadioShack due to their extensive line of radios available, their excellent customer service (they'll even help you program your radio if you need assistance) and the quality of the product offered in relation to the price.  While you're there, be sure to pick-up some additional batteries for your flash lights, and they even have emergency/backup power sources for your cellphone and/or smartphone as well.

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