97L gets disrupted by Hispaniola

By: Dr. Jeff Masters , 12:53 PM GMT on July 21, 2010

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A tropical wave (Invest 97L) near the north coast of Hispaniola has been disrupted by interaction with the island, plus the effects of moderate wind shear of 10 - 20 knots. The storm is no longer a threat to develop into a tropical depression today, and the Hurricane Hunter flight that was scheduled for today has been postponed until Thursday. The disturbance has brought heavy rains of 8+ inches to Culebra, Vieques, the Virgin Islands, and some of the northern Lesser Antilles Islands. Wunderblogger Weather456 reported that the power was knocked out on the island of St. Kitts for about 24 hours, due to the intense lightning associated with 97L. All of Puerto Rico and the Virgin Islands are under flash flood watches today.

Satellite images of 97L show a relatively meager number of heavy thunderstorms that are not well-organized. The curved bands to the north and east of the center have disappeared, and there is no evidence of low-level spiral banding or of a surface circulation. Surface observations over the northern Dominican Republic show only light winds, with no westerly winds indicating that a surface circulation is forming. Long-range radar loops from San Juan show a much reduced amount of thunderstorm activity.


Figure 1. Total radar-estimate rainfall for 97L.

Track Forecast for 97L
The storm is in a fairly straightforward steering current environment, and 97L should progress steadily to the west-northwest through Saturday. The rains from 97L's thunderstorms will bring the threat of isolated flooding to the Dominican Republic today, and to Haiti on today and Thursday. Heavy rains from 97L will affect eastern Cuba, the Turks and Caicos Islands, and the eastern Bahamas Thursday, and South and Central Florida can expect heavy rains to arrive Thursday night or Friday morning. The latest suite of model runs from 2am EDT this morning (6Z) foresee 97L making landfall on the Florida coast somewhere between Miami and Cape Canaveral on Friday, then continuing into the Gulf of Mexico on Saturday. Only the Canadian model foresees a threat to Texas, and the other models predict a second landfall between eastern Louisiana and the Florida Panhandle.

Intensity Forecast for 97L
The primary detriment to development of 97L today will be its close proximity to the landmass of Hispaniola. Once the storm pulls away from the island tonight, 97L has a better chance of development. Also hindering development over the next two days will be the presence of dry, stable air in its path over the Bahamas, thanks to the upper-level low to the north of the Dominican Republic. The SHIPS model predicts shear will stay in the moderate range, 10 - 20 knots, over the next three days, which should allow for some steady development of 97L on Thursday and Friday before it reaches Florida. NHC is giving 97L a 60% chance of developing into a tropical depression by Friday, which is a reasonable forecast. I think there is a 70% chance 97L will eventually become Tropical Storm Bonnie, sometime in the next five days. Sudden rapid development before 97L reaches Florida is unlikely, due to the storm's current state of disorganization and the dry air over the Bahamas. It's very unlikely that 97L has time to organize into a hurricane before hitting Florida. I put the odds of 97L making it to hurricane strength before reaching Florida at 5%, and I give a 20% chance it will be a hurricane in the Gulf of Mexico. The probability of 97L being a hurricane in the Gulf of Mexico will depend heavily upon how long the storm spends over water in the Gulf, which is very uncertain. The environment in the Gulf of Mexico should be favorable for intensification, if passage over Florida does not disrupt the storm too much.

I'll have a new post Thursday morning, or earlier if there's a major change to 97L.

Famed climate scientist Steven Schneider dies
Steven Schneider, one of the most influential and talented climate scientists of our time, died on Monday. Ricky Rood has a tribute to Dr. Schneider in today's blog. Ricky comments, "He is known for feistiness. His last book was Science as a Contact Sport: Inside the Battle to Save Earth's Climate. He was a man who was, bluntly, harassed and threatened by those who did not like his message. He never shrank from the battle."

Jeff Masters

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Quoting Floodman:


A better one:

HAHA A good one! who knew fogarty was so weather attuned :)
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97L to me looks to be at 20.6 N and 70.9 W
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410. CJ5
It appears conditions to the West of 97L have eased a bit and it is possible the storm could begin to develop better in the coming hours.
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Close-ups:



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Stevie Ray Vaughan, Otis Redding, the Neville Brothers, the Allman Brothers...
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Quoting BiloxiIsle:
From Dr Master on August 23, 2005:

The remains of TD 10 continue to fester over the Bahama Islands, and the clouds have taken on that decidedly messy pattern associated with a tropical depression in the formative stages. An exposed low level circulation center is apparent in both visible satellite imagery and winds from the Quikscat satellite. The circulation was north of eastern Cuba and south of the central Bahama Islands, near 22.5N, 76W at 11am EDT. Deep convection is all east of the low level circulation center, and Quickscat winds as high as 30 knots were measured in this area. Observation stations in the vicinity are sparse, and I have not yet seen any pressure falls in those stations close to the system.

The environment surrounding the system is good but not ideal. Water temperatures are quite warm--about 29C, and closer to 31C near the western Bahamas. However, wind shear levels have been increasing somewhat over the past 12 hours and are about 10 - 15 knots (5 -10 knots would be much better.) A small upper-level low just north of the system may act bring some dry air into the system and hamper any upper-level outflow that tries to develop. Another possible problem is the presence of the large landmass of Cuba to the south, which may disrupt the system's circulation if it tracks more westerly. I expect the storm to continue to torment us by very slowly continuing to organize as it moves towards Florida.

The system appears to be tracking west-northwest at a very slow 5 to 10 mph, and the latest "early guidance" shows the storm moving more northwesterly towards Florida over the next few days. However, steering currents are weak and more westerly motion towards Cuba or the Straits of Florida would not be a surprise. Some of the computer models such as the Canadian model strengthen the system into a hurricane over the Gulf of Mexico later in the week. Some very warm water (32C, or almost 90F) lies off the west coast of Florida that model believes will fuel the storm into a hurricane. The GFS model makes the system a weak tropical storm that moves over Florida by Friday, then keeps the system a weak tropical storm as it recurves past the Carolinas. If the system does become a tropical storm, it is unlikely the upper level winds will allow intensification into a hurricane for at least the next three days. By that time, it's anybody's guess what might happen. One thing is for sure--the remains of TD 10 will be a around for a lot longer, they're going nowhere very fast. I expect I'll still be talking about this system next week!

A Hurricane Hunter aircraft is scheduled to visit the remains of TD 10 at 5pm this afternoon to see if a new tropical depression has formed. If so, it will be interesting to see if they call it TD 10 again, since the NHC discussions have been referring to this system as "possibly the remnants of TD 10".
Man this sounds exactly like 97L
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Good morning all...
I see the storm has gotten disorganized again.

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Good morning, Looking at visible looks like it maybe finally far enough away from Hispaniola to be getting a center now. I think we will see this in the next few hrs.
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Quoting cchsweatherman:
Right now, in analyzing RGB satellite imagery, it seems that the low level circulation is coming back and attempting to become better defined and possibly closed at around 20N and 69.9W. When zooming into this area in the last few images, you can really see some defined spin in the lower levels. Now that it has begun pulling apart from Hispanola, it should become better organized.
thats the same thing i am looking at i truly believe we should have a TD tomorrow the only factor that i currently see is the dry air and lack of convection, i also caution everyone that katrina formed in the central bahamas and got to CAT 1 status before landfall in Southflorida the conditions may not be there now but i have seen time after time the same thing happen.
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Quoting extreme236:
14:40 UTC NASA images show some slight building of convection.


Slight, but a start.

Member Since: July 8, 2005 Posts: 259 Comments: 23565
Quoting reedzone:
During the split with 97L, a nice area of convection with great outflow and curve emerged southeast of PR near 64W and 15-16N. Wind shear is currently 20 knots over the area do to 97Ls outflow. Interesting area to say at the least, looks near TD status but the eyes are mind boggling, not even an invest yet, may get tagged if it persists. 97Ls structure continues to organize. If we get a nice DMAX tonight, I believe this should make TD status by Thuyrsday morning or afternoon when recon goes out.

heard that one before
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Quoting gingerbabe:
government mule


Go full out and add the Allman Bros.
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Quoting DestinJeff:
97L: yet another bastion of what "next week" may bring.


Jeff a weak system coming in from our East would actually help our oil situation with East and then Southeast flow around the storm helping to push it back west where it came from. Even when the system would go ashore the Northwest winds on the backside of it could benefit everyone by pushing the oil further offshore where it could continue to evaporate and be eaten by the microbes. We should know more by the weekend of what to expect for next week, for now we just wait and watch it to see what's going to happen!
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government mule
Quoting StormW:


Black Sabbath, Deep Purple, Status Quo, Cream, Grand Funk Railroad.
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Right now, in analyzing RGB satellite imagery, it seems that the low level circulation is coming back and attempting to become better defined and possibly closed at around 20N and 69.9W. When zooming into this area in the last few images, you can really see some defined spin in the lower levels. Now that it has begun pulling apart from Hispanola, it should become better organized.
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the fact of the matter is 97L pretty much collapsed last night and has been having a hard time getting back up, but after looking at the visibleimages there is definatly a good circulation going and thunderstorms are slowly building to the east of the circulation i think we should have a TD sometime tomorrow
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During the split with 97L, a nice area of convection with great outflow and curve emerged southeast of PR near 64W and 15-16N. Wind shear is currently 20 knots over the area do to 97Ls outflow. Interesting area to say at the least, looks near TD status but the eyes are mind boggling, not even an invest yet, may get tagged if it persists. 97Ls structure continues to organize. If we get a nice DMAX tonight, I believe this should make TD status by Thursday morning or afternoon when recon goes out.

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Quoting extreme236:
14:40 UTC NASA images show some slight building of convection.


Any chance of a link to them?
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I actually think 97L went inland 20 miles or so last night.
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Quoting twhcracker:


a good weather song:)






A better one:

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Quoting extreme236:


It's important to realize, what if in August and September things really ramp up and we see something like 6-8 storms each month? We have no way to predict something like that happening, so these predictions really don't matter.

Great point. 2004 is a good example of that. Due to El Nino, 2004 was really only a two month season, but during those two months, 12 of the season's 15 storms formed. That's an average of 6 per month. Now, 2010 does not have El Nino, so if a burst like from 2004 does occur, it'll probably endure for a longer time period. Suddenly, 18 or so named storms doesn't look like a bad forecast. I know it's still too early to forecast, but with conditions like they are, I think that we should be able to get there without trouble. However, if I am wrong, I will gladly take a serving of crow. Only time will tell though.
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For what I can make up from the latest models, it might end up making landfall somewhere between Panama City FL and Fort Walton Beach FL. after it crosses the southern tip of FL. as a weak system, I just wonder if it will have enough juice as to push the oil away from the MS Gulf Coast, but I really doubt it will.
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14:40 UTC NASA images show some slight building of convection.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
97L finally lost its convection that was only due to interaction last night with the ULL and was not self sustaining, now that that convection is gone, people think it's in worst shape now when it actuality......it's in better shape. A visible MLC has been established and appears it is trying to work its way down to the surface. If a surface circulation closes off, we could have a TD in hours at that point.

Good structure > convection
when you're talking about only having one or the other.
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I actually think I see some spin to 97L on the visible satellite...
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Quoting IKE:


Definitely not worth arguing over.


I'm probably not seeing the facts properly anyway.

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Quoting IpswichWeatherCenter:
Am I the only one wondering what the fuss is about 97L?

It isn't exactly organised.
you are definetly not the only one wondering
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Quoting BahaHurican:
Jason, all this crowing is not cool, dude. On the blog "crowing" doesn't mean shouting how "I was right" all over the blog and beating on one's chest. Instead, one gently offers to grill, BBQ, bake, fry or [I've heard it's really good this way] stew the helpings of crow that others will consume.

However, if u practice this more uncouth habit of "crowing", YOU become the crow. Which means the next time you are even slightly wrong [which given the uncertainties of tropical wx could be 12 hours from now- or less] you will definitely get served. And not in a good way.

Be smooth, man, be cool. It's always better to let someone else say, "Hey, this is just what that kid Jase was saying yesterday," instead of tooting ur own horn....

@ P451: NICE graphical depiction of 97L there, meng....

Yah, resemblance has been noted several times. But I think there was some other stuff going on atmospherically that made it a lot easier for Katrina to blow up the way it did...

Hey KOTG, that ULL is providing for some FANTASTIC wx here today....

I disagree with the comment about Jason. I can see u viewing him as obnoxiously overconfident. But he's genuinely trying to focus on the tropics and topical issues and NOT on disrupting blog activities. You may not like him, but don't "lie on him" as we say in the islands.

ONE more thing about Jase: isn't he actually RIGHT about the disruption of 97L by the mtns of Hispaniola? I don't agree that this means the end of 97l - after all, I got hit by Jeanne after the low and midlevel centres got shredded by those same mountains - but give credit where credit is due.

The couth is lacking - he's got it to learn. But the young man is enthusiastic about TROPICAL WX, and I can't find a fault with that. Isn't that why a lot of us are here????



Baha I couldn't agree with you more. He's trying and i have seen him on here before and a lot of the regulars don't have a problem with him.
I think we just need to watch the wave and see what she does.
Sheri
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381. IKE
Quoting IpswichWeatherCenter:
Am I the only one wondering what the fuss is about 97L?

It isn't exactly organised.


Definitely not worth arguing over.
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Quoting stormhank:
Did anyone see the interview last night on TWC..they were talking to someone from this weather agency that was giving out their outlook for the remainder of the hurricane season...they're still calling for 19 11 5 for their number of storms.. I feel the season would really have to rev up to get those numbers..of course with mother nature you never know

The season hasn't gotten going yet.
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Quoting BahaHurican:
Somebody's supposed to be sailing from JAX to PR, but I doubt they will actually CHOOSE to sail through that rough wx... lol


Sounds like a job for Oz. He could put on that shiny suit and set sail with barometer in hand! It would be glorious.
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Its about to tap into some warmer waters too.....watch what happens!
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Is it possible for this 97L to split and develope two centers of circulation?

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Am I the only one wondering what the fuss is about 97L?

It isn't exactly organised.
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I have been ignored by many of you, I will ask again to see if some one gets interested, does anyone has seen that some models are predicting another storm trying to form between the carribean and Africa?

Link
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Quoting Floodman:


This is a weather blog...Black Sabbath, Metallica, David Allan Coe and Wayne Newton


a good weather song:)




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Quoting Skyepony:
slumming the buoys..just beginning to see a few west winds & pressures falling again. We need a well placed ship..
Somebody's supposed to be sailing from JAX to PR, but I doubt they will actually CHOOSE to sail through that rough wx... lol
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I think we have a Closed Surface Low right now...IMO.
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Morning All. NHC's take on track. Forecasting a landfall in northern Broward Co.

48hrs



72hrs

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Quoting wayfaringstranger:
So what is on the IPOD when watching storms (or waiting them out)?

Blake Shleton? Kenny Chesney? Jimmy Buffet?

When it comes to tracking tropical cyclones, I'm a metalhead. My last two songs were courtesy of Black Sabbath and Iron Maiden.

Anyway, looking at the steering flows, I noticed that the deeper steering would actually keep a system further south than a shallow one at the current time. Pretty rare occurrence, and that might be the reason for a leftward shift in the models recently:



Very shallow steering



Very deep steering
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6z nogaps ... 84 hours out


:|



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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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