INTERESTING ANALYSIS

[ROCK]

Found this from a local MET. Its pretty straight foreword and made alot sense even to a novice like me...thougth Id share...


Following are some explanations to the steering strengths and weaknesses that will be governing the influence of Hurricane Frances movement over the coming days ahead.


We'll pick apart the ridge center that is to develop over the northern Atlantic directly to its north by many hundreds of miles. The reason there has not been an appreciable increase in speed and turn back westward yet up to the time of this writing, for which the time is now early this Sunday morning, August 29, is because the ridge has not yet matured, developed, nor expanded.


I trust you will find some results here soon within another 12-24 hrs. in terms of Frances beginning to accelerate and increase its forward speed and bend back to a true westerly heading for both Monday and Tuesday. The transition begins today as Frances should begin responding to the now-developing ridge as it will be developing and building to its north by many hundreds of miles and be situated straight north of it. Let me give in terms of numbers the strength of the ridge center.


Okay, for comparison, on Saturday evening, August 29, 2004, a 588-591 dm mini-center was situated north of it in the North Atlantic in its infancy stages, yet Frances was still getting away with a direction of 300/08 kts at 7 PM on Saturday, which is west-northwest at 9 mph. The GFDL's 00Z & 06Z, 8/29 run revs-up its speed to about 15-17 mph between Monday afternoon and Tuesday morning, but keeps a heading of 280 to 290 degrees. This speed and heading are not the impressive numbers I was looking for, but will have to bite on for now. The acceleration will be a clear indicator that the ridge is acting on Frances.


This ridge, which will flex its muscles soon, is forecast to peak out at 597 dm come Monday afternoon and Monday night, expanding & stretching westward. There are points in time on Monday and Tuesday where Frances can even take a path just south of due west (260 degrees) showing its fangs in a threatening way toward the near shore waters of Puerto Rico, U.S. Virgin Islands and Dominican Republic. In my opinion, these folks are not out of harm's way, for the side-lobe effects from Frances. However, it shouldn't do that south of due west motion for any great extended period of time; it should be a westward motion of 270-280 degrees heading for a majority of its journey on Monday & Tuesday. If it does so, it's going to have to do it on either Monday or Tuesday when the ridging is at its peak which is late Monday. It would not come as a surprise if your NHC had to adjust the adjust the short term track a little to the left in the first 72 hours out through Tuesday evening since that is when the ridge will be in strongest play is on Monday and Tuesday. It is also on Monday and Tuesday when Hurricane Frances should be moving its fastest speed because of the intense ridging forecast to its north, and its most westward heading, too, on Monday and Tuesday. Look for this transition to come late this evening or tonight.


Finally, starting Tuesday night and Wednesday morning, the ridge's ego begins letting up some. It starts to lose some of its intensity deflating down to around 592 dm center on Wednesday morning to its north. This should still be enough to keep it on a heading of 280 to 300 degrees, but the speed should begin slowing down on Wednesday.


Come Thursday when it is forecast by GFS to be in the vicinity of the Southeast Bahamas of the Turks & Caicos Islands, we come back to seeing the same strength of ridge that was over it yesterday on Saturday, August 28, a 588 to 590 dm ridge and center, respectively, still situated to its north. In this condition we seen a west-northwest motion of 300 degrees.


Thursday and Friday are the turning points. At this time, height falls are forecast to occur over the southern Plains states while the ridge "feels" the pressure from a dip in the jet stream over New England. But of greater concern is the height falls over the southern Plains states which are forecast to shift eastward on Friday to the central Gulf coast region. Funny thing, but the Canadian bacon doesn't show such height falls as the GFS does. Oh, I remember, now; it's because I custom set the GFS height falls at a more sensitive setting of every 30 meters instead of the conventional 60 meters that CMC showed. CMC did show a vort lobe stretched through the northern Gulf of Mexico at 144 hours, Friday evening, though. What ensues of this is an erosion of the west side of the ridge over the eastern Gulf of Mexico, late Thursday and Friday. CMC recedes the western side of the ridge; GFS erodes the western side and shifts the ridge northward.


On this basis, then, it stands to reason that Frances will take a turn to the northwest. When it does so, means all the difference as to whether it penetrates the Gulf of Mexico. If Frances' timing is ahead of schedule and zips across the northern edges of the Antilles running ahead of schedule, then it could beat the system and make it into the Gulf of Mexico before the ridge really weakens on its western edge. This is not good for worry warts. It is good for thrill-seeking hurricane fans.


However, when in the event Hurricane Frances slows, while in the vicinity of the Bahamas for which I think there's an excellent chance of this slow-down happening in the vicinity of the Bahamas, it allows and affords more time for the ridge to weaken or deflate.


The one major item that stands out big time, is the forecast pressure field which is indicated by all dynamical output to show a continued vast deepening, or intensifying which is most pronounced when Frances reaches near the vicinity of the Bahamas. A category 5 hurricane is very doable at that time when it will inevitably intersect the relatively very warm currents of the Gulf stream which flows through the southern and eastern Florida straits. However, category 5 intensity is difficult for a hurricane to sustain for much more than a day or two. Typically, once it peaks out at that, it seldom ever reaches it again, later in its life span; for such a high intensity is also a difficult and unstable intensity to remain at. Just go look at the Unisys site and see the time table that historic hurricanes remain at cat 5 level, before stabilizing-off at a lower rating. Anyway, at some point, it looks a near certainty that's going to happen as it has a very bright future ahead in terms of further deepening with a continued anti-cyclone established well atop it. This is the year for intense, major hurricanes.


I'll have this audience know that in the last 8 cycle runs--that's right, 8 consecutive cycle runs of the GFS modeling solution, that it has threatened to bring Hurricane Frances to enter Gulf of Mexico waters. And though I've not been vocal about this the past few days, doesn't mean I don't keep abreast with what's going on under the bridge or behind closed doors.


The 12Z, 18Z 8-27-2004 runs and the 00Z, 06Z, 12Z, 18Z 8-28-2004 and now the newest 00Z, 06Z 8-29-2004 run of the GFS continues in its quest to present Frances to the Eastern Gulf of Mexico waters. It looks tempting to accept 8 consecutive runs into the Gulf of Mexico, doesn't it?


I had a look at ensemble plots.


Many of the ensemble members don't even show the 1000 mb or 996 mb contour as I chose to plot, until it reaches the Bahama Islands. Then, many of the ensemble members wake up and figure out that there's suddenly a cyclone by plotting these SLP's on the map by the time it appears in the Bahamas. So what's that tell you? It only gets stronger!! These global baroclinic models just don't have the very fine mesh tight resolution that the GFDL has, so they cannot accurately gage the true intensity. It's already under-rated the ferocity of Frances. The one or two that get a head start in recognizing Frances while east of the Bahamas take it further north than the operationally accepted main run. I don't like the approach to the Florida coast by the 00Z 8/29 run of GFS. It intersects it on a perpendicular, east-west approach and keeps ramming it westward, until the Gulf of Mexico and then goes northwestward. It should come at a sharply parallel angle to 45 degree angle at most. What I've said about Charley, I'll say it about this one too. At such a violent hurricane intensity, there's a natural tendency to want to curve to the right in the absence of strong ridging, owing to Coriolis. It happened with Charley. It happened with Georges in 1998. The Euro's upper air pattern suggests a thinning, weak ridge to its west, north, and east in the extended period, so a slow-down, even to a crawl, in forward speed looks likely while near the Bahamas. The biggest challenge is not Monday and Tuesday; that's clear-cut. It's from the middle of this coming week and beyond on the handling of how quickly (or slowly) the western side of the ridge decays and recedes. Thrill-seeking hurricane fans will NOT want the ridge to recede or decay quickly. Worry warts should root for it to recede and erode quickly, so's it can allow opportunity to curve northwest and at the end, northward. What has perked my interest is that although I see an erosion of the ridge as it nears Florida, I do NOT see it coming from any major trough, and the ridge is only gradually eroding from the way it looks to me. Because of this slow, gradual erosion, this lends some hope for it to make it to the Eastern Gulf of Mexico. But I'm not in position to take it any farther than that.


I think the bottom line here is that this one should remain to the EAST of New Orleans, even with some margin of error in allowing it to enter Eastern Gulf of Mexico waters, should it even come to that.


(But T. Scott, didn't you realize the several runs of the GFS in showing that it heads it into coastal Mississippi??) Of course I seen that. The GFS has been representing the furthest extreme......the furthest WEST and furthest SOUTH all along for the past few days now from the rest of the normalized pack. I don't forecast for the EXTREME west and south out to 240 hours, because I recognize that the ridge is not going to be at its "A-game" or in its best shape when the rubber meets the pavement at the end of the line as it attempts to near Florida. Nor can I expect a 168 hr to 240 hr (7-10 day forecast) to hold accuracy or merit, either. We suffered horse-ups in just the first 12 hour forecast of getting Charley to go into Port Charlotte rather than Tampa Bay. These errors only compound exponentially with time. I think if I'm going to miss it one way or the other, I would lean toward the Atlantic coast and go up further north. At this point in time, it looks like it will come close to Florida in the extended range. Good thing for Florida that the state is longer than it is wide, so with any luck Frances can miss the peninsula part of it to the east or west. I will say this much. If Hurricane Frances gets within that square box that is north of 25 degrees north WHILE east of 75 degrees west, then it's over, and it's not coming into the Gulf of Mexico, and Bush wins the election again. 2 models show that happening out of a rather large subset. (Remember, T. Scott, he who looks into crystal balls eats glass!!) Yes, yes famous last words. Why don't I just turn around now so you can kick me in the rear, right now, before the 1st quarter even begins?


In some respects these forecast scenarios do resemble a MODIFIED Hurricane David track of 1979,--but MODIFIED at best--, make adjustments to it---bring the first half of its track farther north and shift the second half of its track marginally eastward. 100 miles further west, and then it's a west coast/ Florida panhandle problem. 100 miles further east and it's not a Florida problem at all; it's a Carolina Panther problem!! But I do feel it is going to make that turn to the northwest and then north; it will be at a reduced, slower rate when it does so as weak ridging traps it to the north, east, and west, but also shifts north at the same time. When it does begin to turn right again, I expect a slow-down in the vicinity of the Bahamas; Andros Island; those guys; yeah all 3 flamingos and the one Cuban that lives there. Okay...I lied about the Cuban; he's still Bahamian. They sent the Cuban back in exchange for a native.


Alright, perhaps I'll write about this once again in the next coming days ahead, but I don't think this one has New Orleans' name on it, so I won't be writing that frequently on it; it's just not warranted and accuracy is in jeopardy right now. Watch the speed of Frances to see if it outraces the models' time-table projections like they've done in the Caribbean, though. It should be out ahead of NHC tracks though. NHC always running too slow in their out periods. After inspection of the GFDL speeds which tend to run fast, anyway, shows its highest speed of 15-17 mph and is not that impressively fast on its 00Z-06Z, 8/29 output. The 6Z output that came in shows in the 4.5 to 5 day period a compass heading of between 315 to 330 degrees heading. This means northwest heading. The GFDL still represents one of the eastern-most tracks and has been quite consistent at being so.


We'll also need to inspect how the ridge holds up from Wednesday and beyond as well, to see if newer solutions hold onto the ridge longer or resurrect a re-inforced ridge late in the week, or if, in fact, the ridge breaks down quicker than forecast. If the first materializes, then not good, because the Gulf of Mexico will be assured an entry; if the second materializes, then yet another in a series of North Carolina problems. The intensity forecast is a no-brainer. Expect a major hurricane and upwards to violent, at times, maybe still even as high as Cat. 4-5 level when in the vicinity of the Bahamas. The possiblities as I would release them today are from Florida to North Carolina. Pensacola to Cape Hatteras. This would include any part of the Florida peninsula. This should be a landfalling U.S. major hurricane, the second of its kind in one season. Chase gurus will be in hog heaven. Of all the tracks, I prefer a track closest to the 00Z, August 29 run of the Canadian model. Chances of getting in the Gulf vs. staying in the Atlantic? 40% vs. 60%. I think it will be a good East Coast Florida scare and put a lot of people on edge over that way. I still do not see a threat to New Orleans, though, at this point in time. And in all fairness, the bottom line is that I have once again written way too early on a forecast that is sure to change on Hurricane Frances who has not even passed Puerto Rico's longitude yet at the time and date of this writing. But my typing skills needed the practice, so just play along!


If I see more consensus at a later date for a Gulf of Mexico entry, then I will write again in the future. The westward motion is beginning this morning. 7 AM data shows 275 degree heading at 7 kts and satellite pics this morning have shown westward-moving frames. Now, all that remains is an increase in forward speed which will come within 24-36 hrs as the ridge begins building.

[rbaker]

how long did it take to get the analysis and type this all out. For a new guy, your very in depth and have alot of logic and material to back your theroies. Which I for one, thank, because it has substance, instead of saying 10 days a way its going to hit mia area.
I look forward to your indepth analysis regardless of your expertise or not. Im sure some of the moderators as well as mets on here will do the same.

[MWatkins]

basically sums up it in really really good detail...hope there are no copyright issues...but excellent stuff...what site did that come from so's I can bookmark it?

MW

[Opal storm]

That's like one of the longest posts I've seen on this board,and a good one too Thanks

[Guest]

Thats a good analysis. Sounds like your community is in good hands (with the local meteorologists at least )

[bigmike]

If this is the same rock who posts at the st pete times forum he is indeed an excellent addition to the storm 2k family. His posts are always fun to read on the bucs forum.

[dixiebreeze]

Wow! A good read.

[ROCK]

sorry yall miss understood. AT the top of my post. I received this from a local MET here in Houston. Great guy and pretty knowledgeable.....

[ROCK]

http://www.home.earthlink.net/~pvamagic/

[Stratosphere747]

Would that be Dr.N.Frank??

[ROCK]

Would that be Dr.N.Frank??

No wasnt him be hes a pretty knowledgable guy when it comes to canes....

[Wainfleeter]

That was a very interesting read, even a novice like me understood.

Thanks for posting it Rock.

~DonnaM

[elvinp]

Thank you for the insight and rational analysis of this hurricane event. I visited his Web Site and you can see why he writes so well. HE THINKS, then reacts; not vice versa. A lesson for many on the site.