Archive for the ‘Tropical wave’ Tag

Invest 99L Has Become Tropical Depression AL09


As of late this afternoon, 8-29-2016, Invest 99L has strengthened to a tropical depression.  For up-to-date information on the system, I recommend Dr. Jeff Masters’ weblog (blog).  See link below:

Go to the top of the page and click on News & Blogs.

As of the time of this writing, Dr. Masters expresses reasonable confidence that the system will track in such a way that a landfall will occur somewhere in the Florida coast north of Tampa.  I urge all interested persons to pay close attention to Dr. Masters’ postings, the Weather Channel tropical reports, and your local news.

Here is the most recent version from my favorite spaghetti chart source, the National Center for Atmospheric Research in Boulder, Colorado (CLICK ON IMAGE TO ENLARGE):

2016-8-29 Model tracks


97AL – Tropical System May Become a Threat to Florida


Though there is more than one system out there today, my attention is east of the Lesser Antilles Islands where there is a system that currently has the status of a tropical wave.  However, there is an 80% chance that it will become cyclonic within the next 48 hours.  The Spaghetti chart below is courtesy of Jonathan Vigh.  His efforts to put the model forecasts together produce my favorite renditions.  Notice that the islands between its present location and Florida will be effected if this early visual is close to being correct.  The storms ability to sustain itself as it moves over land might be touch and go.  Frankly, this one really has my attention.

If you left click the image should enlarge – a second left click might enlarge it even further:


Gaston has weakened to the point where it has lost its closed rotation.  This means it has returned to the status of tropical wave (synonymous with tropical disturbance).  However, some of the more dependable computer models expect it to regain strength soon.  My advice is to ignore the CLP5 track in the chart above; it is a baseline derived from recent directional tendencies and is used as a tool “after the fact” to evaluate the accuracy of the more analytical models.

You have probably noticed that I tend to focus on those storms which could be a threat to Florida and the Gulf Coast and once that threat passes I generally assume that you get plenty of continuous information from television news.  Though it is quite repetitive and there is some “drama” I still highly recommend the Weather Channel.  Here is a link to their Hurricane Central page:

We have friends in our West-Central Florida neighborhood, wonderful people, who are currently in Nova Scotia.  Therefore, since some of my concerned neighbors consult this site, I’m including this current statement about Earl’s expected effect upon Canada.  This comes verbatim from the WeatherUnderground website, appearing in Dr. Jeff Masters’ web-log (11:54 am EDT):

Impact of Earl on Canada

“Winds will begin to rise on the southwest coast of Nova Scotia late Friday night and early Saturday morning. By late morning Saturday, Earl is expected to make landfall somewhere between the Maine/New Brunswick border and central Nova Scotia. At that time, Earl will probably be a strong tropical storm with 55 – 60 mph winds. Earl will be moving at a very rapid 25 – 30 mph when it arrives in Canada, and regions on the right side of the eye can expect winds 15 – 20 mph greater than on the left side, due to the fast forward motion of the hurricane. Earl’s impact is likely to be less than 2008’s Hurricane Kyle, the last hurricane to hit Nova Scotia. Kyle hit near Yarmouth, Nova Scotia, as a Category 1 hurricane with 75 mph winds. Kyle produced a storm surge of 2.6 feet, and did $9 million in damage to Canada. The 11am EDT NHC wind probability forecast is calling for a 15% chance of hurricane-force winds in Yarmouth, and 3% in Halifax.”

AFRICAN LOWS 8-27-2010

For those of you who might be “old school” (like me) and enjoy surface pressure plots, I’m posting this current one that shows a line of lows over Northern Africa and Saudi Arabia – all of which are slowly migrating toward the west – which is typical for this time of year.  I’ve marked the cores of these lows in red. They are hot and dry but as soon as they move over the Atlantic they characteristically sweep up great amounts of moisture through evaporation.  Paradoxically, the addition of water vapor lowers the pressure and because of that the systems usually “deepen.”  Increasing winds make waves which increases the water surface for evaporation and whitecaps with bursting bubbles produces ejection filaments which break apart by gravity and cause even more surface to be available for evaporation.  During this phase of the hurricane season for some of these it’s “off to the races” as  tropical cyclonic systems evolve and track across the Atlantic.  Typically, the warmer the water, the higher the evaporation rates and the stronger the storms become.   NOTE:  Remember, the more water vapor in the air the less it weighs per unit volume – therefore the lower the pressure upon the surface. The opportunity for intensification is great because of the great length of ocean over which they can travel.  Once this happens – as long as they are over warm water about the only thing that can make them fade involves the air aloft (its temperature, velocity, and flow pattern).


Though this is probably not news to you – as predicted in the previous posting – activity is picking up out there.  That should be no surprise considering the time of the year.  Once again, I urge you to be prepared for the eventualities of tropical weather if you live in hurricane country.   Having experienced the destruction and aftermath of hurricane Andrew, I can assure you that it doesn’t always happen to “the other guy (or gal)!”

In my family we find that no matter what plans we make – we must not be surprised or angry or disappointed if Mother Nature decides to inconvenience us.  In my opinion it is important to take one day at a time while doing our best to enjoy life and to be of service to others.

Please count on having to be self-sufficient for a while if a damaging/disruptive storm should come through.  When the little things we take for granted are taken away – our lives can suddenly undergo a drastic change.  For example, after Andrew we had no electricity for over 6 weeks.  In spite of the fact that the majority of people who came down to Homestead to help our community were wonderful and extremely well-intentioned – there were some real opportunists too.  A case in point: Generators were trucked down and sold from the back of the trailers for more than 5 times their suggested retail price – cash only – on the line!  The 25′ travel trailer I bought to live in (our house was a total loss) cost $12,995 in our part of Florida before the storm and $17,995 after the storm.  The good news is that my son-in-law found the same model for me from the dealer in Knoxville who sold it to us for $10,000 – and that included delivering it to my driveway in Homestead and showing me the ropes on how to operate the things I knew nothing about.  He and his wife told us that when watching television in the comfort of their home they had been hoping that something would come up where they could be of significant help to a family.  What special people they are!

Only one window was broken by the storm in our home and that was merely a crack.  Why?  We had them all protected with storm shutters.  But – the roof failed!  The shutters don’t protect the contents of a house when the roof comes off – LOL.

A friend of mine who worked at Turkey Point Nuclear Power Plant had quit drinking a couple of years prior to hurricane Andrew.  When I saw him a few days after the storm he told me how happy he was that he had quit because had he been drinking he would have merely sat in his recliner with a bottle (or bottles) and tried to ride out the storm in some state of oblivion.  He said that the storm had moved that recliner 8 yards from its spot in his family room.  I thought to myself, “8 yards – 24 feet – sure – I can visualize that happening – easily.  After all – his family room was the biggest room in the house.  BUT – what he meant was 8 “yards!”  Yes – the chair had been repositioned 8 houses down the street coming to rest in someone else’s back yard.


Thanks to the very fine work by Jonathan Vigh of the Department of Atmospheric Science at Colorado State University I am able to provide you this morning’s model forecasts for Ida.  Left click to enlarge image.


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The image below shows model results for Tropical wave (depression) Henri released at 5 PM EDT, Oct. 8, 2009.

10-8-09 Henri

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A Tropical Wave Worth Watching Has Formed

-l eft click to enlarge this TIME SENSITIVE image -
-left click twice to enlarge this TIME SENSITIVE image –

The chart above, acquired from the tropical page of Weather Underground at shows computer model “notions” of the future path of Investigation 91 which currently has the status of a tropical wave.  The wave (or tropical disturbance) is currently showing no signs of cyclonic circulation.  When, or if, if does it will become a tropical depression.

The red pathway is from the GFS image.  This is the one I’m tending to value the most in this specific case since the GFDL does not take it far enough.  In any case, it is believed that the leading half of an anticyclone moving from the west toward the east will prevent the system from continuing its rightward turning and will eventually cause it to move generally toward the west.

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To have this current explosion of activity in the Gulf and Atlantic after so many quiet weeks is a real attention-getter.  Most recently, a tropical system off the Florida panhandle has developed into a tropical storm.  In the meantime Ana and Bill out in the Atlantic are both commanding attention.

Tropical systems are not all bad, particularly when the wind velocities are not too high and this is because they can provide much needed precipitation.  Let’s hope that these three systems prove to be more of an advantage than anything else.  So many people are reminded of Andrew in 1992, another year in which El Nino was a  factor.  Andrew was the only hurricane to make landfall in the U.S.A. that season but he was a whopper and there are many people yet today who will testify that it changed their lives – myself included.

I am likely to be inactive on this site for the next few days for two reasons.  My laptop is behaving badly and either needs some serious attention (like a new hard drive) or I need to bite the bullet and get another machine.  Also – I will be traveling.  For those of you who know me – don’t be alarmed.  The traveling has nothing to do with the current tropical weather activity.

In the meantime if you want to stay on top of things weatherwise I recommend the Weather Channel if you have cable and also the Masters’ Blog at

The Masters’ Blog link is usually at the upper part of the page on the right hand side.

Peace be with you!


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11:30 PM EST

ON JULY 20, 2009.

A tropical disturbance (also known as a tropical wave) has moved over Barbados and is continuing on its general path toward a direction just a little north of west.  The image above is a color-enhanced infrared.  At the time of this posting, the National Hurricane Center is indicating that they do not expect development into a cyclonic system within the next 48 hours.  To be cyclonic there must be a closed rotation.  tropical depressions, tropical storms, and hurricanes rotate counterclockwise in the northern hemisphere (except in the higher levels of the storms).  For more information on cyclonic circulation in a hurricane go to this link:

My most trusted source, Dr. Jeff Masters, at this time expects the disturbance to be torn apart by upper level wind shear within the next few days.

To follow Dr. Masters’ reports, go to the following link:

Then, in the “Features” bar at the top, click on Tropical/Hurricane.

That will take you to his Wunderblog feature which usually appears on the right hand side of the page.

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