WunderBlog Archive » Category 6™

Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.

Here comes Arlene!

By: Dr. Jeff Masters,

Arlene is gone, leaving behind little in the way of damage, no deaths or injuries, and some beneficial rainfall to areas north of the landafall point that needed it. Overall, I thought the NHC did a nice job forecasting and not overhyping the storm, and the media definitiely overhyped the storm. It's best not to get too excited about June tropical storms! A few rainfall totals from Arlene:

Location Storm total
Panama City FL 5.4
Naples FL 5.3
Fort Myers FL 4.8
Mobile al 4.5
Pace FL 4.4
Homestead FL 4.2
Columbus MS 4.2
West Kendall FL 3.4
Pensacola FL 3.4
Milton FL 3.3
Atmore al 3.3
Macdill AFB FL 3.3

Additionally a cooperative observer near Royal Palm Beach FL
reported 6.8 inches of rain between 7 am June 9 and 7 am CDT June11.

Check out the regional radar landfall loop for Arlene.

Dr. Jeff Masters

Blog Entry for Saturday, June 11
Arlene is finally starting to resemble a hurricane, with a well-defined eye developing, and deep convection starting to wrap around the eye on the north and west sides. There is still a lot of dry air surrounding the storm, though, and that has prevented Arlene from becoming a hurricane. Dry air is frequently the nemesis of June tropical storms, since in June the jet stream is still far enough south that there is plenty of dry continental air being pulled south over the Gulf of Mexico by mid-latitude low pressure systems.

Arlene will likely hit land before much intensification can occur, so the residents of Alabama and Florida will dodge this blow for the most part. It's amazing how close the track of Arlene is to Hurricane Ivan's track!

Looking ahead to the next few days, strong winds over the Caribbean should keep the tropical wave in the eastern part from developing into anything until perhaps Monday or Tuesday, when the winds will relax and potentially allow a new tropical depression to form. Let's put the odds of this happening at about 25%.

Blog Entry from Friday, June 10
Arlene has been strengthening today, with maximum sustained winds at 5pm EDT of 65 mph. But again, the storm looks pretty unimpressive on satellite imagery, with an exposed center with deep convection just beginning to wrap around the center. The main weather is in a narrow band to the northeast of the center, and the central pressure is a very high 997 mb, only 6 mb lower than when the storm formed. Arlene still has a ways to go before it reaches hurricane status--75 mph winds and a well-defined eye--and not much time to get its act together before landfall Saturday. The Florida Panhandle will probably get some minor damage from the storm (less than $10 million), but Arlene may end up being more of a boon than a bane, since it will provide a substantial amount of rainfall to areas that need it. Tropical storms provide a important part of the rainfall the Southeast U.S. needs each year, and area agriculture would suffer greatly without the rains these storms provide.

Blog Entry from Thursday, June 9
Well, we have the first tropical storm of the season, Arlene. As is typical for early-season June storms, Arlene is disorganized and pretty unimpressive looking, with its center devoid of deep convection and tropical storm force winds present only in one modest band northeast of the center. The prospects for the storm to attain hurricane strength appear dim. Upper level winds on the west side of the storm are a little too strong to allow the storm to build up a nice inner core--the winds are disrupting things before they have a chance to get started. Add to this the fact that the sea surface temperatures are still relatively cool, and the storm is only expected to remain over sea until Saturday morning, and you arrive at the conclusion that hurricane status is unlikely for Arlene.

Although the official NHC forecast takes the center of Arlene west of the Florida Panhandle, the Panhandle should take the worst of the storm, since most of the strong winds are in a band northeast of the center. Let's hope that Florida taking the brunt of this first storm of the season is not a portent of things to come--the 2004 hurricane season was quite enough for Florida!

Blog Entry from Wednesday, June 8
Well, the disturbance in the Western Caribbean got its act together enough to become Tropical Depression One. Since the system is moving slowly, and has plenty of warm water and light vertical wind shear to contend with, it is likely to become Tropical Storm Arlene in the next 36 hours. The current NHC forecast brings the storm northward into the Gulf of Mexico, which as we can see by looking at the Historical Map, is typical for a June storm that forms in this location. The polar jet stream is still active this time of year, and creates many southward-extending troughs of low pressure that steer tropical cyclones northward.

It is interesting to note that the 5 tropical cyclones that formed in June in the Western Caribbean all hit the west coast of Florida. The current best guess NHC forecast takes the storm west of the Florida Panhandle, but includes Florida in its cone of probability, so Florida could be picking up where it left the 2004 hurricane season--in the bullseye.
waves at pensacola beach
Stormy Surfing
Stormy Surfing
Tropical Storm Arlene is as good an excuse as any to head to the beach. There were quite a few people there checking out the beach and of course a few surfers.
Beach under water
Beach under water
Most of Crstal Beach, Destin, FL is washed underwater by TS Arlene
TS Arlene 3 hrs Later
TS Arlene 3 hrs Later
At noon, the stairs of the house collapsed

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

It would be quite unusual for this system to grow into a full fledge hurricane so early in the season, especially since the water temperatures haven't even peaked.
I think that 2005 will be another active season, with most of the powerful storms arriving in late August - September.
I was wondering why we don't see the computer models for the FSU super-ensemble? Are those model predictions not for public consumption?
Looks like convection on the west side of the center is increasing this afternoon. Is it possible the Bermuda High forecast to develop would relax those westerlies?
The sheer is expected to weaken over the next 24 hours and become highly favorable for the storm to develop a little more. I still think the ridge to the east of Florida will not develop enough to force this storm much farther west. The latest BAMM Computer model is indicating this as well. I am interested to see the models and the NHC forecast over the next 24-36 hours as to where this storm will head. I expect a land fall in the panhandle of Florida.
I'm in Pensacola, when should we start seeing the affects of Arlene? I'm hearing landfall prediction ranging from Saturday to Sunday afternoon. I also realize that the weather extends outward of the eye about 150 miles. Any realistic idea when we might start seeing the heavy rains and winds from this system?
That nose of 80 degree plus sea water temperatures continues to point at mouth of Mississippi River. However the storm may track a bit to the right.
The FSU Superensemble model is still considered experimental, and is not being made available to the public. However, I don't see why not, considering it was the best-performing model last year.

As for when the weather begins to deteriorate in Pensacola, the best guess is Friday night, with a peak during Saturday morning. However, the storm appears to be moving a bit more slowly than anticipated, so this may delay the onset of stormy weather until Saturday.

Dr. Jeff Masters
Does wundergound.com have all the public models in the computer models link, or are there others made public? If so where?

The storm picked up a little speed and looked like it was going to jog to the west but then it picked back up on a northward track...Still wondering if it will make that turn and stick with it a while and take it away from the Tampa area completely where I live.
http://moe.met.fsu.edu/tcgengifs/ FSU professor Bob Hart creates Animations of most recent model data. GFDL has been having serious issues with its post-landfall forecasts -- it is not weakening it nearly that fast and even has it regaining hurricane strength winds over New England at tau+126 from the 12z run. Recon has recently found 46kt flight winds -- waiting for next QuikSCAT passs to gauge the strength of the surface winds.
I would like to thank Ryanfsu for putting up that link. Very helpfull information on that page. As a charter boat captain the weather can sometimes determine my pay check. Currently here in the Florida keys we are getting some MUCH needed rainfall from Arlene. I must say it is almost pleasant. Fingers crossed for all the storms this year to just be a rain event....
The storm should make landfall somewhere in the florida panhandle. I don't think that the high pressure in the Atlantic will strengthen enough to push Arlene further west. So that means the west coast of florida will get about 3-5 inch. of rain. I have looked through all the records of tropical storms and hurricanes and no hurricane in the last 150 years has ever hit Sarasota County. That means we are due for a big one.
Would Arlene be considered a tropical only storm or a baroclinically enhanced storm should she (as extremely unlikely as it currently appears) make hurricane status?
FSU Superensemble - This is the ONLY model I know of that is totally off limits to the public. I have ultimately gained access to every model out there, & even being an alumni of FSU has gotten me no where. I suspect there is some type of NDA between FSU and NHC. They need to wake up a bit to the currently very disturbing Santorum legislation that is pending in Congress. The fact that they are preventing public access to this clearly superior model is setting a very bad precedent, and it may come back to haunt the entire MET community.
If you are interested in other Professional Opinions, please see my Weather Insite blog (uWX Underground Blog handle is pyrotecnico)
Arlene is a "100% tropical storm." The fact that some upstream baroclinic type forcing may aid in intensifying Arlene has nothing to do with the overall structure of Arlene, which is completely warm core.
I'm a professor at FSU and I still can't figure out why the Superensemble is not accessible. I will try and send some emails to see if I can get a reason.
Does anyone know when this storm is expected to take the turn to the northwest? They said 24 hours yesterday morning.....If it doesn't make the turn it will be in the warmer shallower water of the Gulf the entire track north. I have been experiencing rain I assume associated with this system for a while now. If it doesn't make the turn the entire west coast of Florida will take a good portion of this and I am in Tampa. The BAMM Model which has shown a due north track since yesterday at 8am is still showing the same track. The BAMM Model has been reliable on the weaker storms which are being sheered. It has a good predicition for about 36-48 hours out.
Any thoughts?
I think the reason the FSU model can't be accessed is that if the national hurricane center is using it they don't want folks to see it. The hurricane center knows that no computer model is perfect. If it even looks like a storm MIGHT hit around, say New Orleans, they will take that in on their possible strike chart to encourage an early evacuation. Now what if the public has info about their computer models that shows it is extemely unlikely that New Orleans gets hit. Everyone sits tight. The hurricane center is always going to play it safe and encourage an early evacuation.
True, but we can see most of the other models. So with all due respect, that theory is flawed.
The FSU Superensemble is indeed used by the Hurricane Center, but it is a "late model" and according to a forecaster at a recent seminar at FSU, "It comes off the printer just as we are writing our advisory and can't use it as the basis for our forecast. Yet if there is a drastic inconsistency between our Official Forecast and the FSUSE, we have the ability to change our forecast." NHC has about 45 minutes - 1 hour to actually assess the synoptic situaiton, another hour to interpret models and recon information, and then about an hour to write up the advisories and coordinate with various government agencies -- all this before the next 6 hour period. It is necessary for the model runs to be complete before any analysis can be done. With our present computers, most of the global models can be run in 15 minutes.

As with any experimental model, including HWRF, the replacement to GFDL, any improper use by people (public) that have no skill or background in Hurricane forecasting is extremely dangerous given the hysterical impact the media has residents in the path of a storm. Each respective model has its own strength and weakness. For instance NOGAPS correctly forecast the loop of Jeanne and the landfall location 4.5 days before, while GFS had the system captured by a trough at -40W. The 96-120 hour forecast error was nearly 2000 km. But most of the time, the models do a decent job with 72 hour tracks, but intensity is still a difficult proposition.
ZOLSCH said: I'm a professor at FSU and I still can't figure out why the Superensemble is not accessible. I will try and send some emails to see if I can get a reason.
That would be greatly appreciated! The arguments made by a few about 'iumproper use' by the public is more than 'over the top' -- every other model is publically available through some means -- the fact that this one specific model isn't means there is more to it than meets the eye. There ius some precedent for this same type of arrangement between the airlines and FSL -- but this is a very low profile, industry/gov't relationship. Far different than a Gov't/University relationship that involve public funding. With so many other models available, and a tremendous amount of other data avialable via the military sites as well -- I'm not overly bothered by the lack of access -- but it's a matter of principal, and free public access to dat and information.

The FSUSE is still in the testing stage just as is the HWRF, NCEP's new hurricane model that will be the next generation of numerical weather prediction for tropical cyclones likely going live in 2006.

Read this article about the Superensemble: http://www.research.fsu.edu/scicol/3/teest.html

Interesting line about Dan Rather's journalistic integrity again called into question.

Hence the FSUSE is privately funded.
25. IKE
I live in Defuniak Springs, Florida and believe me...we DON'T need any rain any time soon. We've had enough to last for awhile. Interesting forecast in that our winds aren't suppose to be much above 20 mph...maybe 30 in gusts, but the NEXT county over...Okaloosa County/Crestview has a forecast of gusts to possibly 70 mph! There can't be that much difference in 25 miles of location....someone will be right and someone will be wrong.
You would be suprised. Last year I can remember being at my brothers no more then 20 Miles away and the wind being terrible but where I lived there was next to nothing but rain. 20-30 miles is a big difference wind wise in a storm like this. Especially if you are going to be to the west of the center of ciculation and someone else to the east.
I will have to agree with creekchub00. When Charley hit Port Charlotte last year we really didn't get that much rain or wind and we live in Sarasota which is one county north. As for Arlene it seems the storm is jogging a little bit to the west now that it is almost a hurricane. It will make landfall somewhere between Pensacola and Apalachicola Florida as strong tropical storm 70mph to a weak hurricane 75mph.
Is anyone interested in doing a fun hurricane prediction site...for entertainment purposes only? I would like to do somthing to that effect and link alot of the official stuff back to wunderground.com If you are interested email me at creekchub00@tampabay.rr.com
I have been saying landfall in the panhandle the entire time! Thank you very much!
30. IKE
I understand about the differences in small locations....20 or 30 miles...east vs. west of the center...it's just the forecast for every area around where I live is for winds at least 20 mph higher than where I reside. I think the forecaster goofed...but oh well. Looks like Pensacola might be a bullseye for the worst weather...and points eastward too...hopefully in a lesser degree!
Ahh I didn't realize what you meant there. Yes it is odd if you are all west of the storm and everyone AROUND you has 20mph more wind.
That is the beginning of the site I am thinking of making..
Is anyone noticing that the storm is starting to make a Westward jog and is Intensifying rapidly? The winds in Sarasota are really starting to pick up. We might just get that one band of showers right off are coast. I suspect some strong winds with it. I also beleive that if the storm hadn't intensified as much as it has then it would still be moving pretty much in a due north direction. I beleive the storm will make landfall just east of Pensacola.
33. IKE
I noticed on infrared and wator vapor images of a deepening of Arlene. Looks like a possible hurricane at landfall and it has shifted slightly west which is what the NHC was saying would happen. Looks like a Pensacola/Mobile landfall.
I was in North Port for Charley and our winds probably got up to about 95-100 mph. My mom is in Punta Gorda (and lived through 45 minutes of the eyewall) and the estimated winds there were over 150 MPH with gusts to 180 MPH. On a map North Port is only about 10 miles northwest of Punta Gorda. I know that Charley was a particularly small storm, but it just shows how close to the center of a tightly packed storm you have to be to experience the worst of it. Arlene is pretty large and even a hit in Mobile would be bad for Pensacola. Anyone up there with info on how rebuilding is going after Ivan?
I'm from Tampa vacationing in New England and this is all very nerve-racking. Despite the near-hysterics on Boston local news, tho, family in Tampa say they've just gotten some sprinkles today. Let's hope that's all we get.

BTW, the FSU computer is unavailable. It tried out for the football team and promptly got arrested for shoplifting. ;-)
I am in Clearwater, Fl and after what we have been thru last year, I would really like to know exactly what are the specifics that makes a tropical storm gain strength like Arlene. They mentioned dry air making it gain speed but I thought dry air would make it weaken? Can anyone shed light on this for me? Thanks!
I am also from Clearwater, FL..now I reside in New Port Richey. Most storms this early in the season don't strengthen as rapidly as those later because the water temperature and the upper level winds this time of year. The westerlies are typically stronger causing wind sheer and the water temp is some 5-6 degrees cooler right now then it is in July August September. There are exceptions to every rule obviously but for the most part Tropical Storms this time of year never get extremely strong!
I live in Destin, FL. We have friends who live in Pensacola and they say the process of rebuilding is slow. I travel a lot in between Destin and Navarre (to the west of us where Ivan was very distructive), and I can tell you that there are still a lot of blue tarps on the roofs of people's houses. The building permits in the paper each week are predominately for roofs, windows, awnings, etc. The renourishment projects along the beaches are just starting to make a difference. So this storm has the capacity (?) to undo our beach/dune rebuilding of the last 9 months, and provide insult to injury for those who haven't been able to rebuild/repair their Ivan damaged homes. Our coast is covered right now with unattractive seaweed from the Sargasso Sea (correct if origin is wrong), but what most people don't realize is that this seaweed which appears here every Spring is great for sand capture and dune building. What happens to this natural dune building seaweed over the next 48 hours? I'm not an expert, but I don't think it will be rebuilding dunes. Hey --- let's hope for the best though!!

Unrelated question to this approaching storm. Why were the tornadoes in Ivan's NE quadrant 1 to 60 miles inland so severe (f2s) as opposed to the more typical less severe hurricane spawned tornadoes?
I did some research and was unable to come up with anything substanial...the only thing I can assume is because Ivan was so strong and the rotation of the storm spawned so many tornadoes that it just happened to be the right elements to cause stronger tornadoes.
With all due respect to wunderground.com if anyone one is interested in the earlier proposed website with me please email me...creekchub00@tampabay.rr.com
Ok...I know you cannot make the decision, but I need an opinion. We are going to Cancun on Wednesday 6/15 for 5 days. Weather forecast from Wunderground looks like thunderstorms for most of those days. I assume those relate to "Arlene" but do not understand why since it looks like it is supposed to be mostly out of the Gulf this weekend. So help me on that one. Anyhow, assuming that forecast does relate to Arlene, if it were you would you be trying to change your plans to arrange for our days away in some other part of Mexico (say Baja or the Pacific side)???
Florida Rainfall

Anyone know of any study showing the relationship of the Bermuda High to rainfall in Florida?
43. dcw
Revasarah, arlene should be a swirl of clouds in Nova Scotia by then. To our friend in Pensacola, by the time I post this you've already gotten most of the storm. I'm near Tampa, and right now I'm adding Arlene to my "Dodged Bullets" list. Course, only like 8 storms on the other one so...
The GFS - and I agreed -- has been forecasting Arlene to make landfall very near Mobile, AL for the past 2 days. After years of watching these various models -- the GFS has really become one of the top performers for track forecasts -- and last year, it did incredibably well on all the big storms. The GFS is also very good at forecasting the over all environment in the tropics, and with just a quick glance at several key levels, the GFS was able to provide reliable 10-14 day outlooks for when the tropics would become very active -- and when they would not be conducive to storm formation.
VERY informative article on the FSUSE -- and why it is off limits to anyone of their choosing. However, I highly doubt that ALL the funding for this project, the students working on it, and the staff involved -- is being properly allocated for this project alone. Similar projects in the 1980's and 1990's resulted in class action lawsuits -- poor accounting ended with the termination of the projects. They need to be very careful they have all the I's dotted and T's crossed.

Longer term -- it will be interesting to see if a forecast model co-developed by a Univ and private comapanies can be kept fully out of the public domain -- especially if the model is significantly better than any Gov't run modeling system. But if the model is more dependant on it's massive parallel computing power than actual and better physics modeling -- it may nopt really be that big of a deal.
Arlene appears to have sloweed its forward movement - and an eye like sructure surrounded by rain and convective bands has just about closed off the center -- which is 50nm across. Over the past 30 mins -- radar appears to show the shrinking down of this convective outer wall, or possibly the development of a new, nner wall.

Water temperatures are 81-82 degrees under and to the west of the eye itself, and this is clearing aiding in this re-organization process.

9:55AM CDT
Water vapor imagery show a lot of dry air is now wrapping itself around the west, south and now into the eastern side of the storm. If Arlene is going to intensify any further before finally weakening from the dry air intrusiion, it probably has 1 to 2 hours at most.

Just looked at the water vapor images myself...You arn't kidding...this storms "center" is completley wraped east north and south in dry air.
Arlene's weak 'eye' presentation on MOB radar continues, and the system appears to now be drifting slowly northward at under 8KTS. This is remarkably similar to the "TREND" that was depicted by the GFS yesterday -- relatively fast forward motion to the NNW followed by an abrupt slow down just prior to landfall. While it does not appear that it will precisely follow yesterday's script (will probably make it to the coast a few hours sooner than originally depicted) -- it never ceases to amaze me at just how well the GFS captures these motion nuances so many hours in advance. (2 days before FDrances made it's U-turn in the ATalantic, the GFS forecast that loop and aimed the storm towards Florida.) The BAMM should be put to rest -- I have yet to see where it lends any value to the forecast process any longer. It reminds me of the old barotropic model that continued to be sent out by NMC and used by some people for about 10 years after it had outlived it's usefull life.
With our biggest ride of the season set for Sunday, I'm frustrated with the 50/50 forcasts...
Anybody want to help me go/cancel for Sunday 10AM-4PM in Western North Carolina, Jackson/Macon Counties?
BAMM does allright with the weaker storms, It just doesn't take into account enough of the variables as far as I know to "notice" some of the moves. I think it is a good model to have but not be the sole basis of hurricane prediction. BAMM had it going north farther then any other model but didn't notice the left hand turn it made so suddenly. I had used BAMM for most of my forecasting taking into account the other models and variables such as the ridge to the east of Florida that didn't get as strong as expected as soon as the other models predicted. I am unsure of BAMM because I always though it just was a current trajectory model but I noticed it taking big sweeping turns with this storm. I had never used it before this year, to help in predicting. I believe that was Jeane last year who made the big loop as well, not Frances. Not positive but I think.
As for Arlene it is beginning to weaken, it is virually impossible for this to become a hurricane before landfall in the few hours. 60 MPH sustained winds currently, The visible satellite is showing this storm drawing moisture from the east coast of Florida instead of the west coast. This is do to what Pyro said earlier in that dry air has come in from the west and begun wrapping around the storm. The areas of rain are small and compact right around the center of circulation, and then the moisture moving north over the east coast of Florida which is assoicated with Arlene. If you look at the current radar from Mobile Alabama you can see what resembles and eye just begining to come on shore near Pensacola. the biggest rain in this area is actually to the west of the "center" stretching from east of Jackson, Mississippi south into the gulf. Rain totals have been .5 inches in the past hour with some areas getting 1.75 inches in the past hour. With the dry air moving in this storm should weaken rapidly once it makes landfall, but the rain associate will be around for a while.
Just got back from being at the beach for the last 5 hours in Destin. Arlene's waves and surge with high tide at approx 1:00 created a HUGE MESS for us. All kinds of debris -- beach chairs, tiki huts, signs, etc. --floating down the beach, and yes the dune rebuilding and restoration in a good bit of the area is --- well, let's just say, "down the drain." (Can't imagine Pensacola or Navarre.) Not a lot more here than big waves and storm surge, sustained winds probably 35-40. Maybe 2 to 3 inches of rain. We WILL quickly clean up this mess and continue to have the most beautiful beaches in the US!
With all due respect muffinanne, Sarasota has some of the most beautiful beaches in the US. As for the forcast models BAMM I believe was the only one that forecasted the storm to hit the panhandle though it was some 50 to 60 miles off. I think BAMM model originally predicted Pensacola but I am not sure. The other models did a pretty good job at predicting that westerly movement which BAMM did not. Overall I think you have to use all the models and just mark down the landfall location in the middle of all the models.
Yep - it was Jeanne that did the big loop -- sorry abouyt the name mixup. I really have never seen a case where the BAM (any oif it's iterations) has contributed any value to hurricane track forecasts -- and it cetainly seems like the forecasting community at large does not give the GFS the credit it is due for track forecasting. There are a few 'intensity' forecast models -- but intensity forecasts still remain one area in which there is virtually no skill at all -- certainly nothing better than that exhibted by skilled human forecasters!
Using all the models and 'marking down a landfall location in the middle of all the models' is not a very good idea. A machine can do that. You need to know the strengths and weaknesses - the biasas etc - of each model -- and then assess them within the context of the current environmental 'setup'. You ground truth the models for their initialization -- compare them at their first time steps to see which one is verifying best -- and then determine which one has 'locked in' on the current event.

No mattrer how much I've looked at the BAM -- it offers nothing of real value. It seems to be little more thn a blend of a non-baroclinic stream flow model, with a touch of climatology and persistence.

I understand where you are coming from pyro but it still has some value, I used it as a guide for my forecast because it was predicting the northward pattern farther then any of the other models. I knew "gut instinct" that the ridge wasn't going to strengthen as soon as they said. I guess my educated guess was just in sync with the model, I really didn't use it to forecast the track all that much. So in reality you are right. My theory here is why not use it, it can't hurt. Worst case is the NHC doesn't take it into account unless they have reason to.
It is so confusing which storm did what last year but it was Ivan that did the big loop and came back into the gulf to become a tropical storm again and hit Texas. I remember this because my parents and I went up to Martha's Vineyard when the storm was forecasted to hit the west coast of florida but instead hit Mobile. I left early to fly back to Florida to surf when the storm caused heavy rain and wind in Martha's Vineyard and then looped back into the gulf to reform. Also see Dr. Jeff Masters blog on the track of Ivan. Hurricane Ivan's track!
Ivan was one HUGE anomaly -- in many ways -- including the way the remnants of it came back southeward and then nmoved westward across the Gulf, intensifying back to a T.S. just before hitting Texas. But Jeanne was the storm that headed northward from Puerto Rico/Hispaniola well into the Atlantic - turned eastward, but after a couple days ended up looping westward and eventually hit Florida. The GFS caught the total loop and bringing it back to Florida several days prior to the loop.
Ivan actually split. Part of it went south and hit south Florida again...and the rest went out into the Gulf...that is somthing that you probably won't ever see again in your life time. The GFS has been the best like your said Pyro but I still think the BAMM model has some benifit to forecasting.
Regarding IVAN -- here's a copy of something I sent out to my own readership last year -- including a copy of the internal NHC discussion regarding 'Ivan II':



I have watched the entire process for the past week....and calling this system IVAN is a bit of a stretch, but I do 'see ' their opinion. However, I've seen similar situations involving other systems, and ones I thought were more 'intuitively obvious'...but GOVT forecasters never went ahead and did what the NHC just did. It will make for great historical reading in the future.
It was a bit of a stretch but you can't tell me when looking at the surface pressure analysis that the low pressure that formed wasn't "split" from what was Ivan.

On another note....
The NHC says that another low pressure area in the Carribbean has a chance to develop in the next few days. If it gets to where Arlene formed then maybe but currently there is very dry air moving in quickly from the north and should limit strengthning. In about 72 hours I would watch the west coast of Africa, there is a low pressure system that will possibly spin of the coast and hit VERY warm water and minimal wind shear. The GFS model is showing this "possible low pressure system" Just want to have people keep and eye out over there for the next 72-96 hours.

Stay tuned to www.hurricanes2hell.uni.cc for more information
How right you are Dr. Masters about the media "Over Hyping" this storm. It is so sad how they use the fears of last years "Wicked" season to sell their papers. From my perspective, the Weather Channel did their viewers a huge disservice in reporting this storm.

Case in point. The day Arlene was named a TS, the Weather Channel stated it had winds of 24 MPH. Five minutes later it was 28 MPH. When the finally put their graphics on the screen within 10 minutes, the storm had sustained winds of 30 MPH. There were other inconsistencies, but I believe you get my point.

Those in harms way should get their information from Weather Underground or the NHC.
It is sad, the weather channel is so overrated....they want ratings...they don't care about safety.
All I said it was a bit of a streth -- and I've seen 'better' exmples that warranted such 'continuity'. I never said they were 'wrong'....
With all due respect..I misunderstood you.
Long time lurker. First time poster. One thing bothered me about Arlene. All along everyone was talking about dry air and wind shear keeping most of the power to the northeast of the center. I am no expert but I am curious, why didn't the dry air destory the low pressue area or get to the storms on the northeast side of Arlene?
68. IKE
The thing I got tired of hearing about Arlene was...."this is no IVAN"...I bet I heard that 100 times. Like someone couldn't figure that out....ON THEIR OWN!
Excellent non-technical paper on the effects of Global warming on Hurricanes by several climate and tropical experts.

Pielke, Jr., R. A., C. Landsea, K. Emanuel, M. Mayfield, J. Laver and
R. Pasch

To be published in the BAMS journal soon.

The dry air was wrapping in around the storm. The north east quadrant is typically the "strongest" therefore is the hardest to "infiltrate" with dry air. If you can find a water vapor image around 2 hours before landfall you will see what I am talking about. A looping graphic will be the best to see this. Hope this helps.

That answers the question but brings up another one:

Is a strong northeast quadrant typical of huricanes, if so why?
Intellicast.com is also another good site to visit becuase it has good radar imagery. Using intellicast radar I could see the center of Arlene better then weatherunderground because weatherunderground's radar could not see as far out as Intellicast. I do have to say though weatherunderground does a much better job at tracking hurricanes since you can look at computer models, forecast tracks, ect. I don't think that low pressure coming off of Africa will develop right away because there is still to much sheer in that area and it is extremely rare for a storm to develop in that area. In fact none so far have ever developed in that area in the mounth of June. It does seem impressive right now but it will die down a bit in the next 24 hours or so. The one we will have to watch is the low in the Carribbean. It is rapidly getting better organized and pressures are dropping.
The wind shear forecast I saw was good for the next 48 hour. That area was very favorable.
The NE Quadrant is typical to be honest, I don't know why. That is just a general rule. Astro or Pyro may have the answer. Pyro is a very intelligent guy.

I don't know is a legit answer. I vaguely remenber something about intake and outflows that a tropical system can have or any system (I also remenber tornados usually most southeast to northwest or something like that).

Thanks anyhow
Actually, a lot of the reason the NE side of a hurricane is the least likely to have dry air intrusion has more to do with the fact that the original dynamics and environment that allowed the hurricane to form to begin with is one surrounded by a deep layer of moisture. In the northern hemisphere, the intrusion of dry air almost always will be coming from the west or northwest with storms that are below about 30deg latitude as middle latitude trofs and the westerlies in general bring cooler and drier air in from the west and northwest. The drier air will therefore start 'impinging' on most storms - below 30deg latitude - from the west side or northwest side in association with the approachiung upper level, and in the Fall, lower level trof. Technically though, there is no other reason that the NE side shouldn't also draw in drier air -- if dry air was actually sitting to the north or northeast of the cyclone, it would be drawn in!

In almost all storms, tropical or classic cold core, the strongest vertical lift is almost always located in the northeast 'quadrant' of the low -- and that, in PART, accounts for 'why' the most intense part of a hurricane is normally on the NE side. (Greater lift -- ie stronger upward/vertical motions) results in stronger convective activity -- everything else being equal. Stronger convection, in a hurricane = stronger winds! As a storm begins to move over land (not the eye itself) low level friction leads to a change in momentum in the air above the surface (which is minimal over the ocean surface) which then results in greater vertical wind shears. Greater vertical shears within a thunderstorm predisposes the TRW to produce tornadoes -- though normally, these are relatively small tornadic systems -- almost never of the character of the great F4 or F5 tornadoes that hit the great plains etc. A lot more atmospheric issues relating to astmospheres instability (such as dry air layers, stronger vertical shears etc) make for much stronger tornadoes in the central U.S. In the true CAT 5 hurricanes, it sometimes become impossible to determine if damage was caused by straight line winds associuaterd with the hurricane, or if a tornado cause the damage. This was highliughted with Hurricane Andrew. Some damage near Naranja Lakes -- whgich is just north of Homestead -- was investigated by the NWS and they determined a tornado 'very likely' caused some of the spot damage -- specifically the damage that required about 200mph winds. But this was never officially determined to be the root cause -- it remains conjecture. As an aside, I lived in Naranja Lakes in the early 70's -- all cinder block homes. The entire development was literally wiped off the map -- and never rebuilt.)

Thanks Pryo so if I am hearing you correctly. Because of the way a Tropical System forms all the power is pushed to the NE side because the pressures in a Tropical System create a funnel. And when the system comes over land is basically like throwing the proverbial monkey wrench into the machine, where it starts to fly apart at the seams but their can still be lots of damage from shards of the machine flying around (ie the tornadic systems that form during the death of a tropical system).

Is that correct?
Wow -- your version is pushing poetic license to the extreme - so I'm not 100% sure you got it -- but I think you got the idea! :-)

For those interested in a great archived review of the only recorded South Atlantic hurricane in modern times (March, 2004) take a look here:


I understand and yes I am bad for taking poetic license on things. I should be in Hollywood
There is only one area of significant WX, located well northeast of the Bahamas and was the system the GFS roginallyt forecast to spin up into a marginal T.S. (right in this area) a little over a week ago.

But for those interested, the below VIS Imagery loop, which includes the area of showers and TRW mentiopned above, also depicts a great example of 'sun glint' traveling east to west during the day across the Caribbean. Check it soon, the sun is going down :-)


Ahh Arlene the first of a nut hurricane season