Archive for September, 2008|Monthly archive page
The tropical disturbance off the Yucatan (which I mentioned in a post and marked Saturday on a satellite image) is showing no signs of development. However, a trough extending from it will surely dump some precipitation on parts of Florida. In fact, it’s happening now (9:30 PM EDT, Sunday). The trough is depicted on the surface analysis below from earlier today.
However, according to the NOGAPS computer model, in 4 or 5 days we very well may have a better-developed disturbance forming in about the same location off the Yucatan. This is the time of the year for such activity. The image below is the forecast released at 8 AM EDT today for 132 hours from that time. I have mentioned in this web-log before that forecasts beyond 5 days are often exercises in futility. Let’s see how this one turns out.
If you are interested in watching an animation of the NOGAPS forecast, go to the tab at the top of this page marked “Weather Tutorials.” Scroll down to the topic, How To View Animations of the GFDL Computer Model. As you follow the instructions, instead of clicking on the GFDL simply click on the NOGAPS.
From late September on through the remainder of the official hurricane season, systems that can develop into named storms begin to pop up in the Caribbean and Gulf of Mexico. One such development may be occurring now.
An interesting area in the vicinity of the Yucatan is being watched by the National Hurricane Center. I have marked the approximate center which is hard to pinpoint since there is no apparent closed surface circulation at this time. I may have my blue dot positioned a bit too far to the east. It’s easier to do when using loops rather than stills like this image. If you want to try that, here is a good page to get some nice loops:
I have looked at some of the models on this one and there are indications that it could eventually move toward Florida and provide significant rainfall. It is my opinion that interests along the West Coast of Florida should pay attention to this. Right now the wind shear over the storm is about 20 mph. There is some chance that it could slowly strengthen as it moves toward the northeast later this week. Probably around the middle of the week it will be influencing some part of Florida.
Tonie A. Toney
12:50 PM EDT 9-28-08
Left click to enlarge this image.
At 8 PM EDT this evening Kyle still was maintaining hurricane strength in spite of high wind shear aloft. Generally, a 15 mph wind shear is about the break-off point for being slow enough to allow a hurricane to hold its strength or intensify. It has been greater than that today and is expected to get up to 25 mph tomorrow. However, the winds over the storm are diverging as two cars going down the highway together would diverge a bit if one of them were to move to a lane further from the other car. So, the air over the storm is moving in the same general direction but spreading a bit. When air aloft converges it tends to sink and the opposite happens when air aloft diverges; there tends to be an increase in the amount of air rising from below. This could allow Kyle to maintain hurricane strength tomorrow in spite of the shear. It’s a fine balance and there is some disagreement as to whether it will still be a hurricane tomorrow since at 8 PM the maximum sustained winds were 75 mph and 73 mph would demote it a tropical storm.
It will be interesting to see what happens. Of course, for the sake of the landfall regions and the ships and boats at sea in that area, I hope it weakens quickly.
What follows is a verbatim “copy/paste” of Dr. Jeff Masters’ 9 PM EDT update in his web-log found at WeatherUndergound.com:
“Gulf of Mexico disturbance may threaten western Florida next week
An area of disturbed weather in the southern Gulf of Mexico, just west of Mexico’s Yucatan Peninsula, has changed little today. Visible satellite images show a modest-sized area of heavy thunderstorms moving east-southeast, towards the Yucatan Peninsula. Wind shear is about 15 knots over the region, which is marginal for development. The system should move ashore over the Yucatan Peninsula by Saturday before development into a tropical depression can occur. NHC is giving this system a low (<20% chance) of developing into a tropical depression by Sunday. Early next week, we will have to watch the waters on either side of the Yucatan for possible development of this system. Some of the models are predicting that a tropical depression could form off the coast of the Yucatan Peninsula early next week, then move northeastwards to a landfall in western Florida as early as Wednesday.”
The storm that is at the North Carolina-South Carolina border may look like a hurricane but it is not. The National Weather Service is calling it a non-tropical cyclone. A more common term for such cyclones is “extratropical cyclone.” “Extra” means “outside of.” This refers to their developing outside of the tropics. Hurricanes are tropical cyclones. Even though in the northern hemisphere they both rotate counterclockwise around a central region of low pressure, tropical cyclones have warm cores and are often referred to as “warm core lows.” Relatively cold air occupies part of most extratropical cyclones and this is most certainly the case with this one. The doublet image of the system that I have prepared which you see (above) shows a visible satellite view of the storm earlier today and compares it with a surface analysis. The two do not represent exactly the same time but it’s close; 44 minutes separate them. So, it’s a near match.
For those of you who know your frontal symbols, notice that there are three different types of fronts, all three representing boundaries between relatively warm air and relatively cool air. An occluded front arcs out from the center of the storm and there is a warm front whose axis runs ENE-WSW, and a stationary front curving down to the south.
In spite of the fact that it is extratropical and therefore un-named, it has many of the characteristics of a tropical storm. People located in the storm’s vicinity should be alert to the potential hazards. Also, there is a strong chance that it will interact with tropical storm Kyle in the interesting Fujiwhara effect. If you are interested in that phenomenon, see the following link and also view the post that followed it (at the next higher post location on the page). To do that you will need to scroll to the top of the page and click on the “blog” tab. That will access you to all entries.
I posted an item on Sept. 21, 2008 about the elevated structure with cement block exterior walls at the upper level (pictured at the very end of this entry). That original post is still contained in this web-log. In this post that you are now reading, I am adding additional comments in “blue” to get you (and me) up to date. This has gone back and forth and I hope the identity of the building and the stated design of the block walls is correct. It worries me because anyone in there could have been seriously injured or worse from collapsing cement blocks. This first photograph is of a cement block structure In the Naranja Lakes Condominium Development near Homestead, Florida. In this particular structure there was a fatality due to poured concrete headers and blocks coming down upon a resident huddled inside – a real tragedy. There were at least 3 such fatalities in that neighborhood; it’s amazing that there were not more. TWO INDEPENDENT LEFT CLICKS SHOULD ENLARGE THIS IMAGE A GREAT DEAL.
This next paragraph reflects that I had already made a previous change in the original entry.
It is my understanding that the structure (pictured below) belongs to a yacht club. A reader wrote in after I originally posted this because I had misidentified it as the Houston Yacht Club. However, he indicated that the Houston Yacht Club is “a three story coral colored structure and while some water entered the first floor it is essentially undamaged.” You can check out his comment.
Since then, a couple of readers have identified the building as belonging to the Seabrook Sailing Club just north of the Clear Creek channel. “Kent” adds, “The cinder-block wash-away walls collapsed as designed, leaving the shell structure intact. It was originally built after Hurricane Carla in the early 1960s. Hurricane Alicia did a similar number on the building in 1983. I think the club is trying to decide if they should rebuild on the current shell or scrap it.” End quote.
Though this building is elevated and held fast on its foundation, the surge was too high and the waves too forceful for the cement block. I don’t believe this damage can be attributed directly to wind force but rather, the surge with its waves on top. For those of you who have felt the pounding of moderate surf against your body – imagine what this cement block must have endured before yielding. I see wires and perhaps some straps but I see no evidence of corefill in the block nor do I see very much rebar reinforcement in the image. At the time that I wrote this I had no idea that upper level walls were deliberately built to wash away. If this is true, so much for the contents and/or anyone who might have been unable to get out because they waited too long. On the other hand, maybe it was just used for storage. I had heard of “break-away” lower level walls. In fact I have a friend who built a pole house with that design. For quick information rebar and poured concrete reinforcement read the second paragraph in the following link and click on the photo on the bottom right.
Please visit the rest of this web-log go to “blog” at the top of this page or click here. https://cloudman23.wordpress.com/. If you are interested in weather, there are some tutorials scattered about and more will be added in time.
LEFT CLICK IMAGE TO ENLARGE AND SEE A RADAR LOOP OF IKE AS HE COMES INTO VIEW AND EVENTUALLY MAKES LANDFALL. WATCH FOR A DISTINCT RIGHT TURN TRACKING DIRECTLY TOWARD HOUSTON JUST BEFORE REACHING THE COAST. IF IT HAD CONTINUED STRAIGHT, THE WINDS AND THE SURGE ALONG THE COAST AT GALVESTON AND SOUTHWESTWARD WOULD HAVE BEEN EVEN WORSE BECAUSE THAT COAST WOULD HAVE BEEN CROSSED BY THE RIGHT-HAND LEADING QUADRANT OF THE STORM
(see item 13 below).
23 COMMON MISCONCEPTIONS ABOUT HURRICANES
©* Tonie Ansel Toney (see conditions for copying at the end)
I have learned of these misconceptions by communicating through the years with my students, friends, neighbors, attendees of some of the hurricane seminars that I have conducted and visitors to hurricane expos where I have given presentations. Most of this occurred in Florida. I learned that these items have been relatively “common” misconceptions through informal pre-tests I have given to college students at the beginning of certain semesters, answers to questions I have asked in classes during the course of myriad semesters, through conversations with people of all walks of life (and a broad range of ages and experience), and by listening carefully.
ALL 23 UPPER CASE STATEMENTS ARE FALSE IN SOME WAY. BRIEF EXPLANATIONS FOLLOW.
1. IF THE SPEED OF WIND BLOWING DIRECTLY INTO THE SIDE OF A DWELLING CHANGES FROM 40 MPH TO 80 MPH, THE FORCE THAT IT EXERTS INTO THE STRUCTURE WILL INCREASE TO TWICE WHAT IT WAS. THE TRUTH: A doubling of the velocity will cause a four-fold increase of the force upon a surface being struck at right angles. The relationship is “exponential,” not “linear.”
2. IF, DURING A HURRICANE, YOUR TRUE WIND DIRECTION IS FROM THE SOUTH, THE HURRICANE’S EYE IS TO THE NORTH OF YOU. THE TRUTH: It is generally west of you. Hurricane winds move approximately parallel to (or concentric with) the nearly circular eye-wall. A good rule-of-thumb for eye location (in the Northern Hemisphere) is: Imagine standing with the wind at your back. Extend your left arm out from your side and your hand will be pointing toward the eye.
3. IF AN APPROACHING HURRICANE IS ABOUT ONE DAY AWAY, PRUNING OF TREES IS ADVISABLE. THE TRUTH: It is too late to prune at that time – it should have been done much sooner, preferably prior to the hurricane season. Pruned material must be disposed of properly – if lying around the items can become a dangerous airborne hazards. Please read on by clicking here; there are 20 more which might interest you. And, don’t miss viewing the animated image of Ike at the beginning of this post.
Though if it does occur it won’t be as stark as this Pacific Ocean weather event, but it should still be quite interesting. If you are interested please read the previous post. If this is the only one you see, scroll to the top of the page and click “Blog” or go to https://cloudman23.wordpress.com/
Tonie A. Toney (Cloudman23)
There is a possibility that the very interesting Fujiwhara effect might occur within the next few days. In the image above I have placed a red dot upon the tropical disturbance that is tormenting Puerto Rico and Eastern Hispaniola and a light blue dot upon an extratropical low that is off the Eastern Seaboard and probably kicking up some big waves. If the tropical system shoots north as the models are predicting, the two could interact in the Fujiwhara effect. Here is a well-written link about that phenomenon.
The extratropical system might even back up a bit in response to a rotation around a common axis with the tropical system. Go to this link now if you would like to see a rendition of what might happen: (There are four helpful buttons – reverse, stop. forward, and single step).
SPECIAL NOTE: THE LINK IMMEDIATELY ABOVE IS VERY TIME SENSITIVE. IT MAY NOT SHOW WHAT I’VE DISCUSSED IN THIS BLOG UNLESS YOU VIEW IT ON THE DAY THIS WAS POSTED. AFTERWARDS THE FORECAST MIGHT CHANGE. IF THE FUJIWHARA EFFECT ACTUALLY COMES TO FRUITION WE WILL BE ABLE TO SEE IT VIA LOOPS THAT ACCELERATE TIME.
Of course, I did not come up with this notion on my own. My tip came from the WeatherUnderground blog posted by Dr. Jeff Masters at 10:43 AM EDT today (September 23, 2008). He also mentioned it yesterday.
Natural processes can be lethal and cause heartbreak but they can also be breathtakingly beautiful. If the Fujiwhara effect happens to occur, perhaps we will have the opportunity to watch two spiraling systems dance together for a while, just as spiraling galaxies can do as they get close to each other. Let’s hope the prediction is “right on” and that we can focus upon an event that is NOT creating havoc as did Ike. Enjoy!
“Plot provided courtesy of Jonathan Vigh, Colorado State University. For more information about this graphic, click here.”
THIS IS A TIME-SENSITIVE POST
FROM SEPTEMBER 22, 2008
Dr. Jeff Masters of http://www.wunderground.com/tropical/ reports flash floods and mudslides in Puerto Rico from the tropical disturbance in their vicinity. Please check it out. His weather blog is excellent. You will find it on the right side of the page.
The models are all over the place today. The GDFL model has been, in my opinion, the best performer over the last couple of years at least. Please disregard the CLP5 model and the XTRP model. They are no-skill models that do have a useful purpose but they are not meant to convey an actual forecast. One day I may write about those models to explain their function but if you are bugged by it and can’t wait, I suggest a Google search.
Please visit the rest of this web-log at https://cloudman23.wordpress.com/. If you are interested in weather, there are some tutorial items scattered about and more will be added in time. At the end of this page there is a cue to click to the previous page or the next page.