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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2162. Grothar
Quoting tropics21:
No we do not have a 98L just someones hypecasting


Navy just put 98L up!
Post in a few minutes
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Very interesting to note on the newest CIMMS shear map.. Look at the curve of light wind shear near 97L, which btw is now under 10-20 knots form what it looks.. It looks like (if you go by frames) the area of light wind shear is pushing the heavier shears along with the ULL westward. This should make conditions good for development of 97L, but would it be TD3 or TD4 or Bonnie or Colin? Let's see what surprises 98L can bring..

CIMMS shear map
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2159. unf97
Quoting NCHurricane2009:


There is no tropical wave in the eastern Caribbean Sea in the NHC surface analysis:

http://www.nhc.noaa.gov/tafb/ATSA_12Z.gif

Check this satellite loop out. Click on HDW-H to see the upper-level winds over the eastern Caribbean:
http://www.ssd.noaa.gov/goes/east/watl/flash-ir4.html
Do you see the anticyclonic spin over the eastern Caribbean in the HDW-H vectors? You can also see that the flow is branching (splitting) on the SE side of the anticyclone. The branching, upper divergence is triggering those E Caribbean storms, not a tropical wave.


Ahh, I stand corrected. I overlooked the divergent flow in the eastern Carribean. Initally, I thought it was an inverted trough or wave that had moved into that region, but instead you clarified that for me. Thanks again.
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Quoting tropics21:
No we do not have a 98L just someones hypecasting




yes we do
Member Since: May 21, 2006 Posts: 5091 Comments: 115239
Quoting CybrTeddy:


Models keep it over water for at least 48 hours so yes it does have time to become a TS, otherwise the NHC wouldn't have declared it an invest.

oh k just asking.
sheri
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2154. JLPR2


It has been a harsh day for 97L, it fought off some dry air that was to its west and the ULL was pretty close, but you can see the dry air moving away and the ULL accelerating towards the west.
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Quoting NCHurricane2009:


http://www.ssd.noaa.gov/eumet/eatl/avn-l.jpg

Don't see organization with the EATL wave.

not organization, potential is the word, alot of invests lacked organization but they had potential, sometimes neither organization or potential makes the grade, its basically just watch, wait and see, you can cut it either way.
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Quoting jurakantaino:


Action:
Quote
| Ignore User





am i wounder if they made it too where you wont see there commets if you have some one on Ignore



hmmm whats see




Quoting CaribBoy:


From nothing to Red circle. THAT WOULD BE CRAZY. Tropics are heating up





any any one noted this yet???
Member Since: May 21, 2006 Posts: 5091 Comments: 115239
Quoting unf97:
The wave in the eastern Carribean SE of Puerto Rico won't develop in the immediate short term due to its proximity to 97L. The outflow from 97L is blowing the convective cloud tops S-SE, as indicated on satelitte imagery.

If the eastern Carribean wave may have a chance of developing in a few days after whatever becomes of 97L moves off farther west and northwest.

there is also a mid level ridge which is also circulating 97L outflow..

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
247 PM AST WED JUL 21 2010

SYNOPSIS...TROPICAL WAVE NORTH OF THE DOMINICAN REPUBLIC WILL
CONTINUE TO MOVE AWAY FROM THE LOCAL AREA THIS EVENING. MID-UPPER
LEVEL RIDGE WILL BUILD OVR THE LOCAL AREA OVR THE NEXT 24 HRS.
Member Since: September 1, 2009 Posts: 23 Comments: 1007


Look at purple model . LOL
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Quoting WeatherNerdPR:
Could you imagine waking up Saturday morning with two Tropical Storms? Would be pretty cool to me.


yeah as long as they both aren't going to affect anyone....which w/ these 2 seems rather unlikely
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2147. cg2916
Quoting NCHurricane2009:


This is how 98L emerged. Its a long story actually. How do I know? I use the surface analsyes at the NHC to see what's going on day to day in the surface across the Atlantic tropics. That's my source.

Step 1) Remember that Caribbean Sea disuturbance in the central Caribbean last week? A broad surface low pressure area materialized east of Nicaragua from this, which was soon absorbed by a tropical wave moving in from the east. The absorbing wave moved westward into the western Caribbean, Yucatan, and into the southern Gulf of Mexico, where it interacted this week with a cut-off upper low in the Gulf. The upper low dominated as all clouds organized around it instead of the surface wave, preventing development.

Step 2) Now, remember that tropical wave south of Jamaica on the evening of July 19? I was really surprised that wave never developed. I also remember saying that would become 97L instead of the 97L we have now. It was under low shear and good outflow from a western Caribbean upper-level ridge, so I was surprised it didn't develop. This wave continued westward across the western Caribbean Sea, and also into the southern Gulf of Mexico.

3) Both tropical waves merged int the western Gulf of Mexico in the last few hours, creating a large, monsoonal like low pressure system in the western Gulf of Mexico which is now Invest 98L. The cut-off upper low in the Gulf has moved westward out of the area, and now the disturbance is underneath anticyclonic upper ridging with relatively high upper atmospheric pressurs between the cut-off low to its west and the other cut-off low to the east (the eastern cut-off low is the same one that is shearing 97L). This has a better chance than poor ol' 97L which is suffering from shear.


Oh, I get it.
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Quoting ackee:
97L IS JUST over hype invest dont think it will even make it to TD status Do WE HAVE OFFICAL HAVE 98L?
Member Since: July 31, 2008 Posts: 0 Comments: 730
Could you imagine waking up Saturday morning with two Tropical Storms? Would be pretty cool to me.
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Quoting cg2916:
Where did 98L come from? How is it more of a threat than 97L?


This is how 98L emerged. Its a long story actually. How do I know? I use the surface analsyes at the NHC to see what's going on day to day in the surface across the Atlantic tropics. That's my source.

Step 1) Remember that Caribbean Sea disuturbance in the central Caribbean last week? A broad surface low pressure area materialized east of Nicaragua from this, which was soon absorbed by a tropical wave moving in from the east. The absorbing wave moved westward into the western Caribbean, Yucatan, and into the southern Gulf of Mexico, where it interacted this week with a cut-off upper low in the Gulf. The upper low dominated as all clouds organized around it instead of the surface wave, preventing development.

Step 2) Now, remember that tropical wave south of Jamaica on the evening of July 19? I was really surprised that wave never developed. I also remember saying that would become 97L instead of the 97L we have now. It was under low shear and good outflow from a western Caribbean upper-level ridge, so I was surprised it didn't develop. This wave continued westward across the western Caribbean Sea, and also into the southern Gulf of Mexico.

3) Both tropical waves merged int the western Gulf of Mexico in the last few hours, creating a large, monsoonal like low pressure system in the western Gulf of Mexico which is now Invest 98L. The cut-off upper low in the Gulf has moved westward out of the area, and now the disturbance is underneath anticyclonic upper ridging with relatively high upper atmospheric pressurs between the cut-off low to its west and the other cut-off low to the east (the eastern cut-off low is the same one that is shearing 97L). This has a better chance than poor ol' 97L which is suffering from shear.
Member Since: September 15, 2009 Posts: 494 Comments: 3688
Quoting cg2916:


Really? It popped out of nowhere!
No. IMO it is the wave that moved west from Jamaica a few days ago.
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Another image of Chanthu.

Member Since: October 25, 2005 Posts: 19 Comments: 22322
2140. JLPR2
Quoting WeatherNerdPR:

How sad...


How come? Thats good news, one disturbance less. :D
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Quoting JLPR2:
What remains of the E-ATL disturbance, it was never a TW.



Also there is no TW in the eastern Caribbean, that's a piece that broke off 97L



seems like all the waves that come off africa dip about 5° south after they get off, jajajaja
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I feel like if 98L had gradually developed with the current appearance it would be at 50% chance at least. However, because it was such a quick genesis, NHC will probably go with 20% for consistency. It has enough time to become something, thats for sure. Great conditions overhead and underneath.
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Impressive.

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97L looks a little better organized. Still needs that shear to decrease to really develop.
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Quoting JLPR2:
What remains of the E-ATL disturbance, it was never a TW.



Also there is no TW in the eastern Caribbean, that's a piece that broke off 97L


How sad...
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Quoting extreme236:


It still has around 48 hours. I don't know where people are getting this stuff.



i 2nd that
Member Since: May 21, 2006 Posts: 5091 Comments: 115239
Quoting SLU:
98L MIGHT RUN INTO LAND SOONER RATHER THAN LATER THUS INHIBITING DEVELOPMENT. THEREFORE A 10% - 20% CHANCE OF DEVELOPMENT SOUNDS MOST REALISTIC.


It still has around 48 hours. I don't know where people are getting this stuff.
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2132. cg2916
Where did 98L come from? How is it more of a threat than 97L?
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OK anyone have a COC of 98L? Best Guess?
Member Since: August 14, 2007 Posts: 0 Comments: 439
Quoting unf97:
The wave in the eastern Carribean SE of Puerto Rico won't develop in the immediate short term due to its proximity to 97L. The outflow from 97L is blowing the convective cloud tops S-SE, as indicated on satelitte imagery.

The eastern Carribean wave may have a chance of developing in a few days after whatever becomes of 97L moves off farther west and northwest.


There is no tropical wave in the eastern Caribbean Sea in the NHC surface analysis:

http://www.nhc.noaa.gov/tafb/ATSA_12Z.gif

Check this satellite loop out. Click on HDW-H to see the upper-level winds over the eastern Caribbean:
http://www.ssd.noaa.gov/goes/east/watl/flash-ir4.html
Do you see the anticyclonic spin over the eastern Caribbean in the HDW-H vectors? You can also see that the flow is branching (splitting) on the SE side of the anticyclone. The branching, upper divergence is triggering those E Caribbean storms, not a tropical wave.
Member Since: September 15, 2009 Posts: 494 Comments: 3688
2129. cg2916
Quoting HarleyStormDude52:


HAVE THEY NAMED THE ONE IN boc AN INVEST?


Yes, 98L.
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Quoting KEEPEROFTHEGATE:
INV/98/L
MARK
20.5N/93.2W


yea!!!!
Member Since: July 8, 2010 Posts: 0 Comments: 345
2127. JLPR2
What remains of the E-ATL disturbance, it was never a TW.



Also there is no TW in the eastern Caribbean, that's a piece that broke off 97L

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As the ULL pulls west of 97L, the invest is slowly organizing in convection and structure. I believe this will look better in the morning.



98L, no explaination here, there will be a battle going on for "TD3 or Bonnie" tomorrow.

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Quoting jurakantaino:
I thought that mess in the antilles was humidity or left 0vers by 97L?



nop new wave
Member Since: May 21, 2006 Posts: 5091 Comments: 115239
Quoting extreme236:


Well we didn't need the Navy to confirm it lol


I need one link to confirm that and I found this one.
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2123. SLU
98L MIGHT RUN INTO LAND SOONER RATHER THAN LATER THUS INHIBITING DEVELOPMENT. THEREFORE A 10% - 20% CHANCE OF DEVELOPMENT SOUNDS MOST REALISTIC.
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Quoting whipster:


Yes


HAVE THEY NAMED THE ONE IN boc AN INVEST?
Member Since: July 8, 2010 Posts: 0 Comments: 345
2121. cg2916
Quoting CybrTeddy:


I have an entire blog dedicated to 97L. If you want to know my opinion go there. For the time being, 98L is a more imminent threat to develop and closer to land.


Really? It popped out of nowhere!
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Quoting Tazmanian:
all so we need too watch this wave by the Lesser Antilles

I thought that mess in the antilles was humidity or left 0vers by 97L?
Member Since: July 31, 2008 Posts: 0 Comments: 730
Quoting Acere25:
Teddy, plz, thoughts on 97L, for change?


I have an entire blog dedicated to 97L. If you want to know my opinion go there. For the time being, 98L is a more imminent threat to develop and closer to land.
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2118. leo305
Visible satellite shows the cumulus moving from east to west were 98L is.. so it's not suprising there's west wind..

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Quoting WeatherNerdPR:

98L is in the Bay of Campeche, when I was referring to the west african waves I meant that we should watch if any emerging wave shows signs of development.

WNPR~ Oh ok I didn't know if we might have one out there to watch 2, I know the other day there was a very healthy wave that came off but i don't know what happened to it. I promise I wasn't trying to be a smarta$$ by asking, I just didn't know that's all. Thanks for answering my ?.
sheri
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Quoting TexasHurricane:
Do we have 2 invests? 97L and one in the BOC?


Yes
Member Since: August 14, 2007 Posts: 0 Comments: 439
2114. EricSFL
Quoting CaribBoy:


From nothing to Red circle. THAT WOULD BE CRAZY. Tropics are heating up


Not the first time it happens.
Member Since: May 26, 2010 Posts: 0 Comments: 803
Do we have 2 invests? 97L and one in the BOC?
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They declared it an invest, they might do what they did for TD16 in 2008, they didn't even mention pre-TD16 in one TWO, the next it was a red alert.
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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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