2000 EDT  17 AUGUST  2012

In my last update in the tropical section I went to some detail about how the pattern and set up in the MDR  -  the Main Development Rregion — of the Atlantic Basin was still set up quite favorably and was going to remain that way probably through the end of the month.

Since I made that update a few days ago things   have clearly trended    with continued above normal activity.   The strong tropical wave which came off Africa last week–  the feature which the operational GFS consistently blew up into a major East Coast hurricane– turned out to sea harmlessly earlier in this week.  In doing so it showed that the GFS was off by about 2000 miles.   In any  event that system developed into a tropical storm GORDON a few days ago .  The remains of tropical discretion #7  held  together and regenerated in the bay of Campeche Sea yesterday and was upgraded to tropical storm  HELENE this afternoon .    Of course even though we are seeing above normal activity …none of this tropical activity so far has  become a  really big deal.  After all it is a El Nino …. or at least so we are told but as you can tell from the overall weather patterns   (the crippling  heat /  drought in the CONUS …  the  lack of rain in Southern Brazil in South America….  and in Australia…  this is  turning  out to be a pretty abnormal El Nino event .

This first image shows us the current MJO impulse   from the British European and GFS models.  As you can see they all forecast the MJO to move steadily through phase 1 and 2  over the next 10 days.  By the  beginning of September   the MJO might actually reach phase 3.   As I stated several times  over the past few weeks  research clearly shows that there a much higher than normal probability of tropical cyclone development IF  and ONLY IF…  there is some sort of tropical feature which might develop.  In other words  MJO does not cause  tropical cyclone development…  It just enhances the likelihood that a feature might develop.

In addition the latest  200 Mb  vertical velocity plots from CPC shows more extremely favorable conditions moving into the MDR.  I have been talked about this development  for few weeks and  things are  really looking  favorable over the next 10 to 14 days.  A particular importance is a cluster of strong rising motion in the atmosphere   (lots of green) that is moving into the Gulf and the Caribbean over the next few days.  Eventually this energy will move into the tropical Atlantic just as any potential system coming in from Africa heads towards the Caribbean or the Bahamas.

The problem is that we have a very strong system which is come off the southwest African Coast and the past  36 hours or so.  You can see some the images here of this impressive system  (94L)which is a large a massive tropical wave with a tremendous amount convection already in the system.

It’s also are fairly low latitude…  And as you can see from the satellite image   from CIMSS…   the dust coming off of Northwest Africa appears to be fairly far to the north of the system.  if so… then  this tropical disturbance designated  94 L  should   not be impacted by the dust as so many systems so far this season have .

In addition as we can see the ward temperatures continue to warm nicely in the tropical eastern and central Atlantic…  Which should also in the developer of the system.

The latest  WIND SHEAR  maps from CIMSS shows really like shear conditions across the entire tropical Atlantic especially  south of  15N.

But decides the system being fairly far to the south the pattern is set up so that there will be   large and powerful western Atlantic   Ridge covering much of the central and Western Atlantic Ocean.   This are ridge is known as the W.A.R. or western Atlantic rage that you may know of  the more common name  –   ” the BERMUDA HIGH”.

This is very important because 94L  is  really  far south  and by staying at a  fairly low latitude as it approaches the Northeast Caribbean   ( 60 degrees west Longitude)   the  strong ridge or dome in the Western Atlantic Ocean  get a chance to Build    towards the  USA   East coast.   In doing so  the  WAR  will protect  it  from any sort of  cold fronts or troughs  that might come off the East Coast.

The European model has been particularly bullish on the system now for several days.  Here  is an image of the last three runs of the operational European …  And as you can clearly see the trend is towards the Bahamas and wore the Southeast U.S. Coast at day 10.

Now keep in mind the European model is not showing the landfall here but the trend is towards the coast and that is what’s important given that this event is still 10 days out.

Here  is a comparison of the 12Z   Friday European operational and the European  ensemble  at   120  hrs / 5 days.  As you can see we have a large huge dome in the Central Atlantic Ocean which will prevent this system from turning out to sea too early.

Next we have the  day 10  European model also from  12z  FRIDAY .  What’s noticeable here is the remarkable agreement between the operational   euro and the  ensemble.  The key as you can clearly see on the model is how strong the western flank of the Bermuda high ideas.  This is always a critical aspect in forecasting any East Coast hurricane threat.

Indeed if we look at some the spaghetti diagrams of the European ensemble  from m0z  FRIDAY  and 12z   FRIDAY  that you can get from STORMVISTA.COM     (you really have to get an accoutn there… there model stuff  is  best   there is) …  We can also see this shift towards the Bahamas and the southeast coast  at 204   hrs  and to a lessor degree  at 240 hrs.

And looking at the actual operational European model at day 10 we can see the tropical cyclone possibly intense major hurricane nearing the Bahamas off the floor to coast.  We also see what appears to be a decent sized trough over the East Coast.  Now it’s 10 days out   so  one  has to wonder IF that trough  is for real or …..is it being overdone by the model??   We also see a new heat dome developing over the lower planes and the southwestern states….  And if that heat dome builds and faster   then  the  trough  along the East Coast would be weaker   and this in turn would increase the chances of the hurricane hitting the Southeast U.S. Coast.

As you can see there a lots of possibilities here.

what about the    GFS  Model?  Quite frankly I don’t care with this model has to say about  94L and its   development.  There are several reasons for this.  First  let me remind you that the GFS model has a resolution problem after 192 hours which is day 8.  If you don’t know what that means it refers to  the GFS Model which has a different resolution after 192 hours out to  384 hrs  ( day 16).  This simply is not enough computing power over at  HPC/ EMC to run the GFS model at the same resolution all way through  to  384   /  Day 16.  As a result the model is famous for having these massive flip flops and inconsistencies  AFTER   192 hrs.  The European and Canadian models for example do not have this problem but the only one the model 2x a  day.    This is critically important when you are considering  why the GFS model past day 8   does so poorly in figuring out the development and tracks of tropical systems.

SECOND  as I  mentioned earlier the  GFS  model  did an absolutely atrocious job  in  forecasting the strong tropical wave from last week  that came off the African Coast.  If you recall the model developed into a major hurricane that threatened to hit the U.S. east coast around August  21-22.   The   system did not develop into a major hurricane and the GFS model    was off by more than 2000 miles.  Why would anybody give a rat’s an us about the GFS this far out in time.?

 At this point you may ask … what about the   vaunted European model…  How did that  model handle that system which later on became tropical storm  GORDON?  In fact the European took the system and turned it harmlessly out to sea in the Central Atlantic Ocean and then curve to back up towards the azores….  which is pretty darn close to what the GORDON  has actually done.

Anyway if you really do want to take a look at the  GFS models with regard to 94L… here they are.  First we can take a look of the GFS model and see what it  is doing differently on a large scale from the European model.  It has the hurricane or tropical cyclone nearing the Leeward islands in the Northeast Caribbean as a pretty big system  August 25 but be cause the model has a much weaker western Atlantic Ridge  the GFS turns the tropical cyclone out to sea east of Puerto Rico.

Not surprisingly all since all of the hurricane models are based primarily off the GFS and the GFS grid it should not be a surprise that all of the hurricane models from this morning turned this tropical cyclone out to sea east of Puerto Rico.   Monkey   see  Monkey do  right ?

It  turns   out  however   that the 18z hurricane models have turn   much closer to the European solution in showing a track much further to the southwest and implying a  closer  track towards the northeast Leeward  islands.

SUMMARY:   there appears to be a high probability of a significant tropical cyclone in the cape verde    hurricane pipeline coming down which could be develop into a category 3+  hurricane at some point in its lifecycle over the next 10 or 12 days.    In general ….looking at the overall pattern  AT THIS TIME….  it does not appear to be what I would call favorable for East Coast hurricane strike and if I had to make a bet right now I would favor a near miss with the tropical cyclone passing between Bermuda and the East Coast.     But there are still a ton of possibilities out there and a ton of variables.  I do believe that this is NOT going to turn out to sea EARLY  and that the dust will not affect it and it has a high potential to become a significant hurricane.  There are several additional benchmarks to watch….  For example if this TC   ere to pass through the Northeast Caribbean / Leewards  islands … THAT  would greatly increase the chance of a U.S. landfall.  Likewise if this system were to pass close to the Bahamas  THAT    also would increase the chances of the U.S. landfall.

And lastly I have notice the date of possible close passage to the East coast which should be around August 28 or 29 ….  one year ago to the day that Irene came into Eastern Virginia and Eastern North Carolina.