Dr. Jeff Masters' WunderBlog

Little change to 93L; Brazilian floods kill 42
Posted by: Dr. Jeff Masters, 14:18:GMT den 23. juni 2010 +6
There has been little change over the past 24 hours to the tropical wave (Invest 93L) located a few hundred miles south of Haiti. The storm has brought heavy rains to the waters south of Hispaniola, with radar precipitation estimates from the Puerto Rico radar of over six inches of rain in the past day. The heaviest rains have avoided land areas so far. Satellite loops show a very disorganized system, with no low-level spiral bands and only limited heavy thunderstorm activity. There are no signs of a surface circulation visible on satellite imagery. Pressures at the ground stations surrounding the storm (Bahahona and Kingston) are not falling. Water vapor satellite loops show that moist air surrounds 93L, though there is a modest patch of dry air to the storm's southwest. This dry air is likely contributing to the lack of heavy thunderstorms on 93L's west side, slowing development. Wind shear is a low 5 - 15 knots. The high wind shear associated with the strong winds of the subtropical jet stream are over the northern Caribbean, too far north to interfere with development, but close enough to provide good upper-level outflow for the storm. Visible satellite loops show high level cirrus clouds streaming away from 93L to the northeast, evidence of the upper-level outflow channel that is developing to the storm's north. Sea Surface Temperatures are plenty warm, a record 29 - 30°C. The Madden-Julian oscillation (MJO) currently favors upward motion over the Caribbean, which will act to increase the chances of tropical storm formation this week. The main negative for 93L continues to be the lack of spin. The University of Wisconsin 850 mb relative vorticity analysis is showing that spin at 850 mb (roughly 5,000 feet in altitude) has increased over the past day, but 93L needs to acquire additional spin before it can grow more organized. The Hurricane Hunters are on call to investigate 93L Thursday afternoon. Today's flight was canceled, due to 93L's lack of development.


Figure 1. Morning visible satellite image of the central Caribbean disturbance 93L.

Track forecast for 93L
NHC is giving 93L a 30% chance of developing into a tropical depression by Friday morning, which is a reasonable forecast. Given the storm's current lack of spin and relatively modest amount of heavy thunderstorms, the earliest I'd expect 93L to become a tropical depression would be Thursday afternoon, with Friday more likely. Wind shear is expected to be low, less than 10 knots, over the central and western Caribbean this week. Water temperatures will be warm, dry air limited, and the MJO favorable. I don't see any major impediments to the storm becoming a tropical depression by Friday, except for possible interaction with land. There is a low (less than 20% chance) of 93L becoming a hurricane in the Caribbean. Expect 93L to bring flooding rains of 3 - 6 inches to Jamaica, eastern Cuba, and southwestern Haiti today through Thursday. These rains will spread to the Cayman Islands and central Cuba by Thursday through Friday, and western Cuba and Mexico's Yucatan Peninsula on Friday and Saturday. The current run of the SHIPS model has 93L slowing down late this week to a forward speed of just 7 knots (8 mph) from its current speed of about 10 mph, in response to a weakening in the steering currents. A trough of low pressure is expected to swing down over the Eastern U.S. on Monday. If this trough is strong enough and 93L develops significantly, the storm could get pulled northwards and make landfall along the northern Gulf of Mexico coast. This is the solution of the ECMWF, GFDL, and HWRF models. This seems like a likely solution, since recent runs of most of the models have been showing a stronger trough. If 93L stays weak and/or the trough is not so strong, the storm would get pushed west-northwestwards towards the Texas coast. This is the solution of the NOGAPS and Canadian models, which foresee a more westerly track for 93L across the Yucatan Peninsula, with the storm eventually threatening Texas by Monday or Tuesday. The GFS and UKMET models do not develop 93L. A likely landfall location is highly uncertain this point, and the storm could hit virtually anywhere along the Gulf of Mexico coast from South Texas to the Florida Panhandle given the current uncertainty in its development, and the strength of next Monday's trough that may steer 93L northwards.

Intensity forecast for 93L
Forecasting the amount of wind shear in the Gulf of Mexico next week is problematic. There is currently a band of high shear near 30 knots over the Gulf, and most of the models predict that this band of high shear will lift northwards, keeping low wind shear over the Gulf next week. This should allow 93L to intensify to at least a 50 mph tropical storm, as predicted by the HWRF model. The GFDL and ECMWF models are calling for 93L to become a Category 1 or 2 hurricane, and this is certainly a possibility. I expect 93L will become Tropical Storm Alex in the Gulf of Mexico next week, and give a 20% chance that it will become a hurricane.

Elsewhere in the tropics
None of the reliable computer models is calling for tropical cyclone formation in the Atlantic over the next seven days.


Figure 2. Total accumulated precipitation in millimeters (left) for the 7-day period ending at 8am EDT June 21, 2010. The yellow colors (200+ mm, 8+ inches) are where extreme flooding was observed. Satellite image from NASA's MODIS instrument (right) for June 17, 2010, showing heavy thunderstorms over the Alagoas state of Brazil. Image credit: NASA and NOAA Climate Prediction Service.

Floods in Brazil kill dozens
Heavy rains over the past week in the northeast state of Alagoas in Brazil have led to major flooding that has killed at least 42 people. Six hundred people are still missing. This weekend rains in Alagoas and Pernambuco states are the latest in a series of devastating floods to strike Brazil this year. Since the start of Brazil's rainy season last November, 488 people have been killed by flooding and 7.5 million have been affected in 10 states. Much of the heavy rains can be blamed on El Niño, which ended in May. In April, flooding and landslides triggered by torrential rain killed at least 229 people and did $13.3 billion in damage in the Rio de Janeiro area.

It's been a bad year for floods, and there are two other major flooding disasters that have occurred in the past week. In China, the death toll has risen to 211 people, with 119 people missing, because of flooding in the southern portion of the country. France suffered a flash flood last week that killed 25.

Wind and ocean current forecast for the BP oil disaster
East to southeast winds of 10 - 15 knots will blow in the northern Gulf of Mexico today through Sunday, according to the latest marine forecast from NOAA. The resulting weak ocean currents should push the oil to the west and northwest onto portions of the Louisiana and Alabama coasts, according to the latest trajectory forecasts from NOAA and the State of Louisiana. I would expect Mississippi to have its most serious threat of oil yet early next week as these winds continue. The longer range outlook is uncertain, and will depend upon what 93L does.

Resources for the BP oil disaster
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's interactive mapping tool allows one to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

Jeff Masters
Categories: Flood Hurricane
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2001. HurricaneSwirl 00:23:GMT den 24. juni 2010    
Does anyone know why the EPAC has had 4 systems in the past two weeks (TD Two-E, Blas, Celia, Darby) when we're going into a La Nina, but last year when we were going into El Nino we couldn't get anything?
Member Since: juli 7, 2008 Posts: 2 Comments: 3237
2002. MiamiHurricanes09 00:24:GMT den 24. juni 2010    
Quoting Hurricanes101:
93L was never supposed to develop before Friday anyway; even the ECMWF said that

the ECMWF also said that a low would not form with 93L until tomorrow

So it is pretty much on schedule, lack of patience = misinformation
Exactly!!
Member Since: september 2, 2009 Posts: 129 Comments: 19976
2004. Hurricanes101 00:24:GMT den 24. juni 2010    
Quoting HurricaneSwirl:
Does anyone know why the EPAC has had 4 systems in the past two weeks (TD Two-E, Blas, Celia, Darby) when we're going into a La Nina, but last year when we were going into El Nino we couldn't get anything?


strong MJO concentrated over the EPAC plus good timing

Member Since: mars 10, 2010 Posts: 1 Comments: 6902
2006. MiamiHurricanes09 00:24:GMT den 24. juni 2010    
Quoting HurricaneSwirl:
Does anyone know why the EPAC has had 4 systems in the past two weeks (TD Two-E, Blas, Celia, Darby) when we're going into a La Nina, but last year when we were going into El Nino we couldn't get anything?
Favorable conditions and lots of upward motion.
Member Since: september 2, 2009 Posts: 129 Comments: 19976
2007. Hurricanes101 00:24:GMT den 24. juni 2010    
Quoting MiamiHurricanes09:
Exactly!!


It amazes me that so many seem to ignore that fact
Member Since: mars 10, 2010 Posts: 1 Comments: 6902
2009. Tazmanian 00:24:GMT den 24. juni 2010    
the # 1 rule nevere evere give up on a storm


re called 94L one year we where all thinking it was poof then BOOM!!! it came back and made it too cat 5
Member Since: mai 21, 2006 Posts: 5088 Comments: 111338
2013. Hurricanes101 00:25:GMT den 24. juni 2010    
Quoting Tazmanian:
the # 1 rule nevere evere give up on a storm


re called 94L one year we where all thinking it was poof then BOOM!!! it came back and made it too cat 5


If I remember right, that storm was Felix in 2007
Member Since: mars 10, 2010 Posts: 1 Comments: 6902
2014. xcool 00:25:GMT den 24. juni 2010    



Member Since: september 26, 2009 Posts: 2 Comments: 15501
2015. TropicalNonsense 00:25:GMT den 24. juni 2010    
Quoting btwntx08:

lower caps plz also shear isnt that high that dhear to the west should get out of the way



IS THERE LIKE A WUNDERGROUND STATUTE FOR THAT? LOL

Member Since: juli 3, 2007 Posts: 0 Comments: 524
2016. MrstormX 00:26:GMT den 24. juni 2010    
Quoting weatherwatcher12:

Keep alert because the watch lasts for an hour and a half longer.


I will, although I think msot of the instability was used up in the last storm, but idk.
Member Since: mai 27, 2009 Posts: 0 Comments: 4228
2017. nash28 00:26:GMT den 24. juni 2010    
Ok, just got done with the obs and dinner so here is my quick take on 93L as I am very tired and won't be long for this world..

All of the mojo is there for this to develop, but in my humble opinion, I do not believe this will gain anymore than a TD status, if it even gets that. We're dealing with multiple competing vorts (MLV) and the system is basically eating itself up by these vorts sucking energy from each other. Also, this invest has not been able to obtain the spin needed to consolodate the convection.
Member Since: juli 11, 2005 Posts: 190 Comments: 16972
2018. MississippiWx 00:26:GMT den 24. juni 2010    
Quoting MiamiHurricanes09:
I don't find computer models a reason to RIP 93L as they have been doing poorly with it so far. I basically don't listen to them right now and look at current trends and forecasts as they seem to be much more accurate. I still think there is a pretty high chance of 93L developing into a TD and don't see a reason why it shouldn't, except for it running into land.


I probably shouldn't rely too much on models since this is such a complicated setup, but I think a couple of them are starting to get the right idea. Land is about to become an issue. If 93L doesn't strengthen and feel a poleward movement it's going to run straight into the Yucatan and never develop. Maybe on the other side in the Bay of Campeche or Western Gulf, but it wouldn't have time to strengthen into much of anything. Its other option is to slow its forward movement. Tonight is the most crucial night for its development process.
Member Since: juli 15, 2006 Posts: 13 Comments: 8547
2019. MiamiHurricanes09 00:26:GMT den 24. juni 2010    
Quoting Hurricanes101:


It amazes me that so many seem to ignore that fact
Me too. Even though the circulation is improving and convection is increasing, people say "RIP!". Like you said the lack of patience is tremendous.
Member Since: september 2, 2009 Posts: 129 Comments: 19976
2021. centex 00:26:GMT den 24. juni 2010    
What happens when it rains alot on the Caymens? Looking like two days of rain starting in earnest tomorrow and slow mover.
Member Since: august 10, 2007 Posts: 0 Comments: 2856
2022. robert88 00:26:GMT den 24. juni 2010    
Shear to the W/SW seems to be the biggest problem for 93L. It would be rolling up pretty good right now if it wasn't for that.
Member Since: mai 22, 2010 Posts: 0 Comments: 877
2023. Tazmanian 00:27:GMT den 24. juni 2010    
i think 94L was Felix
Member Since: mai 21, 2006 Posts: 5088 Comments: 111338
2024. FLWeatherFreak91 00:27:GMT den 24. juni 2010    
Quoting centex:
What happens when it rains alot on the Caymens? Looking like two days of rain starting in earnest tomorrow and slow mover.
I don't think they have a freshwater flooding problem there... I think it just runs off.
Member Since: desember 1, 2006 Posts: 2 Comments: 3458
2026. bballerf50 00:27:GMT den 24. juni 2010    
Why does it seem like there is a low level circulation just southwest of Haiti, with convection firing?
Member Since: juli 3, 2008 Posts: 0 Comments: 97
2027. HurricaneSwirl 00:28:GMT den 24. juni 2010    
Quoting Hurricanes101:


strong MJO concentrated over the EPAC plus good timing



Quoting MiamiHurricanes09:
Favorable conditions and lots of upward motion.


But isn't La Nina supposed to make unfavorable conditions? I guess it was pretty much timing. A small window opened up and everything took advantage of it.
Member Since: juli 7, 2008 Posts: 2 Comments: 3237
2029. MiamiHurricanes09 00:29:GMT den 24. juni 2010    
Quoting MississippiWx:


I probably shouldn't rely too much on models since this is such a complicated setup, but I think a couple of them are starting to get the right idea. Land is about to become an issue. If 93L doesn't strengthen and feel a poleward movement it's going to run straight into the Yucatan and never develop. Maybe on the other side in the Bay of Campeche or Western Gulf, but it wouldn't have time to strengthen into much of anything. Its other option is to slow its forward movement. Tonight is the most crucial night for its development process.
Agree and disagree. The time for it to develop is tomorrow and Friday. Tonight we need it to develop a low level center and improve on structure, but everything else you said I agree with.
Member Since: september 2, 2009 Posts: 129 Comments: 19976
2030. Hurricanes101 00:29:GMT den 24. juni 2010    
Quoting HurricaneSwirl:




But isn't La Nina supposed to make unfavorable conditions? I guess it was pretty much timing. A small window opened up and everything took advantage of it.


but the MJO creates favorable conditions
Member Since: mars 10, 2010 Posts: 1 Comments: 6902
2031. HurricaneSwirl 00:29:GMT den 24. juni 2010    
Quoting MiamiHurricanes09:
Me too. Even though the circulation is improving and convection is increasing, people say "RIP!". Like you said the lack of patience is tremendous.


IMO it's looking its best yet. System looks a lot closer together than it did this morning. Still has a while to go though. I don't think anything will happen until Friday.
Member Since: juli 7, 2008 Posts: 2 Comments: 3237
2032. Tazmanian 00:29:GMT den 24. juni 2010    
Quoting Acemmett90:
DR TAZ u are needed in the emergancy room we have a stage 5 troll that need to be spayed



but am out of spayed
Member Since: mai 21, 2006 Posts: 5088 Comments: 111338
2033. CaneWarning 00:29:GMT den 24. juni 2010    
Is anybody from Penscoila Beach on? Are things really as bad as they make it appear on the news?
Member Since: april 26, 2009 Posts: 3 Comments: 3667
2034. muddertracker 00:29:GMT den 24. juni 2010    
Remember...have your trolls spayed or neutered!
Member Since: august 16, 2007 Posts: 1 Comments: 2119
2035. Hurricanes101 00:30:GMT den 24. juni 2010    
Quoting F4PHANTOM:
But isn't it running out of time? it will be interacting with the Yucatan in 48 hrs.


some would make you think that, but steering forecasts indicate this may never hit the Yucatan and if it does it wont do it for another 3-4 days
Member Since: mars 10, 2010 Posts: 1 Comments: 6902
2036. pottery 00:30:GMT den 24. juni 2010    
Quoting centex:
What happens when it rains alot on the Caymens? Looking like two days of rain starting in earnest tomorrow and slow mover.

Only a few drops, well directed, manage to actually hit the Islands
They are really small, and make a small target.

J/K, LOL
Member Since: Oktober 24, 2005 Posts: 0 Comments: 20708
2037. RTLSNK (Mod) 00:30:GMT den 24. juni 2010    
Quoting pottery:

How you do, Snake.?
Have you dried out?
(your garden, I mean)
One has to be so careful ....


Quite so my good man, 96*F today at 1600 hrs, will have to turn on the new sprinkler system in the early morning hours, Sugar Bear informed me this evening that her Abutilons are drooping. Can't have that now can we? :)
Member Since: september 3, 2008 Posts: 0 Comments: 15176
2039. Patrap 00:30:GMT den 24. juni 2010    
93L Floater - Visible Loop




Tropical Cyclone Heat Potential Loop
Member Since: juli 3, 2005 Posts: 370 Comments: 111297
2041. MiamiHurricanes09 00:31:GMT den 24. juni 2010    
Member Since: september 2, 2009 Posts: 129 Comments: 19976
2042. kmanislander 00:31:GMT den 24. juni 2010    
Out for dinner but will be back later
Member Since: august 19, 2006 Posts: 0 Comments: 14939
2045. Tazmanian 00:31:GMT den 24. juni 2010    
Quoting Acemmett90:

use a knife then



that would be called muder then
Member Since: mai 21, 2006 Posts: 5088 Comments: 111338
2047. MiamiHurricanes09 00:32:GMT den 24. juni 2010    
Quoting HurricaneSwirl:




But isn't La Nina supposed to make unfavorable conditions? I guess it was pretty much timing. A small window opened up and everything took advantage of it.
Exactly.
Member Since: september 2, 2009 Posts: 129 Comments: 19976
2048. MississippiWx 00:32:GMT den 24. juni 2010    
Quoting MiamiHurricanes09:
Agree and disagree. The time for it to develop is tomorrow and Friday. Tonight we need it to develop a low level center and improve on structure, but everything else you said I agree with.


Biggest thing is patience. If it develops, it develops. If it doesn't, oh well. Good for us. I'm just not liking how a center cannot establish itself. It may or may not be in the process of doing that currently. Interesting stuff, indeed.
Member Since: juli 15, 2006 Posts: 13 Comments: 8547
2050. CaneWarning 00:32:GMT den 24. juni 2010    
You would think a troll would use his user name to get banned for something more offensive. Didn't one of the trolls last year link to porno websites? LOL
Member Since: april 26, 2009 Posts: 3 Comments: 3667
2051. HurricaneSwirl 00:33:GMT den 24. juni 2010    
Quoting Hurricanes101:


but the MJO creates favorable conditions


I know it allows for more convection and moisture across the area with an upward MJO, which relieves systems from dry air, but I don't recall it making any other conditions more favorable such as shear, I honestly don't know about that though, so I'm not gonna argue against it. The MJO factor is probably right, considering last year I don't remember a single decent upward MJO and that's probably why we didn't get anything.
Member Since: juli 7, 2008 Posts: 2 Comments: 3237

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About JeffMasters
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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