Fay - Will She be Feeble or Ferocious?

Hi all -

After spending several days flying into the disturbance that is now T.S. Fay, it's obvious that we still have a lot to learn about tropical systems and how to predict their motion and intensity.  From the previous posting to today's, you can see that there have been some major changes in the track forecasts.  Look at the two shown here - one from yesterday and the current forecast from 2:00 p.m. this afternoon.  I'm showing the spaghetti models from the Colorado State University website because they are visually better than most.  The first one to the right is the 2:00 a.m. forecast run on the 14th, Wednesday morning.  Compare that to the 

 model run this afternoon at 2:00 p.m.  There's a world of difference.  If the latest runs even begin to verify in three days time, our base in Tampa at MacDill AFB will be in the line of fire.  The real question, though is how strong will Fay be when she arrives.  Most models hint at a strong tropical storm to a weak hurricane.  That's good news, but the longer she stays out over the Gulf waters, the stronger she is likely to be.  For the record, 

 official 5 p.m. Saturday NHC forecast is shown here.  You can check the latest official forecast by going to the NHC website at:  http://www.nhc.noaa.gov.

So, what has NOAA been doing this week to better understand how and why these week systems develop into storms?  The two NOAA WP-3Ds, as you know, have been in Barbados flying round-the-clock missions to collect doppler radar data from which 3-D horizontal wind fields can be derived which will then be fed into the NOAA hurricane forecast model (HWRF).  Beginning Wednesday night at 11 p.m. and finishing last night at 7 p.m., these two aircraft flew four consecutive missions into the disturbance, the last resulting in the naming of the system.

To give you some idea of the type of track flown on one of these missions, here is the track shown on Google Earth for the flight flown Thursday night when the system was just east of Puerto Rico.  The different colors represent different wind speeds and the barbs show the direction of the wind at each location.  While clearly there was a circulation at the aircraft's altitude, 12,000 ft., this had not extended to the surface.  Thus, it was still officially a wave.  On the next flight during the day yesterday, Friday, a circulation was found at the surface just south of Hispanola and Fay was born.

Although the P-3s have completed their missions and will be returning to Tampa tomorrow, the NOAA G-IV is currently flying a high-altitude surveillance track out of our home base in 

 to provide profile data for the track forecast models that will be run this evening at 8:00 p.m. this evening.  While the artwork isn't all that great, the track for this flight is shown to the left.  The aircraft will first fly to the east of Florida, then south of Cuba, west through the Yucatan Strait into the Gulf and then back into MacDill AFB.  The mission will take 8 hours, but the data provided to the models should give us a much better handle on where the storm is going.

My best advice to all is to stay tuned, watch the Weather Channel and be ready.  I'll update this again when I have new material to post.  

Thanks for your nice comments on the blog.