Archive for the ‘Tropical disturbance’ Tag
Compare this to the previous posting which was 24 hours earlier and you will see some change in the tracking model forecasts – which is to be expected.
I have greatest confidence in the TVCA run which is a consensus of 5 other models which have been good performers over the last few years. Generally, the TVCA model is very close to the National Hurricane Center’s “official” track that is the basis for the “uncertainty” cones released to the public. If you are one to pay attention to which models get mentioned or shown in weather reports you have surely heard of the “European model” which is labeled ECMWF. You won’t find it on these spaghetti illustrations; Data from this model is restricted from being redistributed according to international agreement. However, the National Weather Service official track runs very close to being the same as the ECMWF. The BAMM and related models are still useful for long term runs but in this case I think you can pretty much ignore them (the ones that run off toward the west).
Suppose you lived along the Nature Coast of Florida, (e.g. Citrus County) then you might feel that you have nothing to be concerned about because the tracks seem to be shifting northward. But please remember, these tracks are merely forecasting the storm’s center. In most cases the strongest winds are at the right hand, leading quadrant of such storms, which, in this case might cause Citrus County some concerns.
Please be sure to click on the graphic for enlargement.
THIS IS A TIME-SENSITIVE POSTING SUBMITTED 8-20-2011 LATE MORNING EASTERN TIME.
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:
Left clicks on this graphic should enlarge it for you.
THIS IS A TIME-SENSITIVE POSTING SUBMITTED 7-30-2011 LATE EVENING.
This is the GFDL model’s forecast for system 91L 126 hours from the 2 PM Eastern time release (today 7-30-2011). Note that it is shown to be north of Eastern Cuba. I calculate the forecast time to be 5.25 days (or 5 days and 6 hours) beyond the release time. That would be Thursday, August 4 at 8 PM Eastern time. This, of course is a forecast loaded with unknowns and fickle variables so one should not consider it a “given.” The GFDL model (Geophysical Fluid Dynamics Laboratory) has impressed me over the last few years. I’m posting this now so that perhaps on Thursday night you might want to check to see how close it is. This posting is not intended to alarm anyone needlessly. If you are in a position where you like to plan ahead and are potentially in the path of tropical systems from the Atlantic and Gulf of Mexico, I advise you to pay close attention to forecasts available to you. It is my opinion that the Weather Channel on television does a great job covering tropical weather and I highly recommend it as a source. Also, on the right hand margin of this page under Miscellaneous/Other you will find a link to the on-line Weather Channel. I also highly recommend the tropical weather blog of Dr. Jeff Masters. Here is a link: http://www.wunderground.com/blog/JeffMasters/article.html
Here is the forecast plot for our first tropical disturbance of the season – released at 1200 Greenwich Time (7AM Eastern Time) June 1, 2011 – the first official day of the season. These are sometimes called spaghetti charts. Please ignore the “straight line” projection into the Gulf which is an extrapolation of movement were there to be no change in course. Already, I’ve detected rightward deflection in its actual track. Two left clicks should fully enlarge this image for you.
The graphic below shows this morning’s computer model forecast tracks for the low (98L) that is currently developing and under investigation in the Western Caribbean.
RELEASED BY THE NATIONAL HURRICANE CENTER AT 8 AM EASTERN DAYLIGHT TIME, SEPT. 4, 2010. “SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH THE REMNANTS OF GASTON CONTINUE TO SHOW SIGNS OF ORGANIZATION THIS MORNING. ENVIRONMENTAL CONDITIONS ARE CONDUCIVE FOR RE-DEVELOPMENT OF THIS SYSTEM AND A TROPICAL DEPRESSION COULD RE-FORM IN THIS AREA LATER TODAY OR TONIGHT. THERE IS A HIGH CHANCE...70 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE AGAIN DURING THE NEXT 48 HOURS AS IT MOVES WESTWARD AT ABOUT 10 MPH.” The color image above was completed at 7:45 am EDT today. This black and white image below at 12:15 pm EDT (4.5 hours later). Information inserted in yellow print was done by me, Tonie Ansel Toney.
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.
We are entering the peak of the Atlantic hurricane season. If you have not been influence by tropical activity thus far this year you might be under the impression that it’s an inactive season. That would not be true. Statistically, it has been about average to date. Though we cannot “plan the future” I feel strongly that we should plan “FOR” certain eventualities in the future. I urge you to be prepared and alert in the event that a tropical system comes your way.
The following statement in “blue” was taken Verbatim Thursday morning (8-19-2010) from the Dr. Jeff Masters web-log found at http://www.wunderground.com/tropical/.
“The GFS, NOGAPS, and ECMWF models continue to predict that a tropical storm will form between Africa and the Lesser Antilles Islands sometime in the period 3 – 6 days from now. There is an area of disturbed weather south of the Cape Verdes Islands, but there is no obvious organization to the cloud pattern. Wind shear is a hefty 20 – 30 knots in the region, and the disturbance is a 1 – 2 day journey away from reaching a lower shear area where development can occur. Preliminary indications are that if a storm did develop in this region, it would track west-northwest and pass well to the northeast of the Lesser Antilles Islands 7 – 8 days from now. However, 7-day forecasts of a storm that hasn’t even formed yet are not to be trusted.”
I have taken the liberty of trimming the latest full disc color satellite image down to a manageable size where you can still easily find Florida and thus look across the Atlantic to see the area of disturbed weather off Africa to which Dr. Masters refers. Two independent left clicks on this image will enlarge it fully. This image was taken from a distance over three earth diameters away from the surface yet there is considerable detail. I hope you enjoy it.
The chart above, acquired from the tropical page of Weather Underground at http://www.wunderground.com/tropical/ 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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