Large and intensifying Hurricane Alex bears down on northeastern Mexico, South Texas

By: Dr. Jeff Masters , 2:23 PM GMT on June 30, 2010

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Hurricane Alex continues to intensify as it slowly bears down on the coast of northeastern Mexico. Brownsville long-range radar shows the spiral bands of Alex, which has dumped heavy rains of up to four inches in northeastern Mexico and near Brownsville, according to satellite estimates of rainfall. The Brownsville airport received 0.78" of rain in the hour ending at 8am CDT, and 0.61" in the hour ending at 9am CDT. Floods from Alex have already killed ten people--six in Nicaragua, and two each in El Salvador and Guatemala.


Figure 1. Snapshot of the Brownsville long-range radar showing Hurricane Alex approaching the coast.

The 7:12am CDT eye penetration of the Hurricane Hunters found a central pressure of 959 mb, a modest 2 mb drop from the reading four hours previous to that. They noted a very tiny eye, ten miles in diameter, with a gap in the northwest side. Tiny eyes like this tend to be unstable, and in the 9:05am CDT eye penetration, the Hurricane Hunters found that the inner eyewall had collapsed, and the pressure had risen 2 mb, to 961 mb. A new, much larger eye will form today as the day progresses. During these "eyewall replacement cycles", a hurricane will typically weaken a few millibars , and the strongest winds will spread out over a larger area as the hurricane conserves angular momentum. Thus, the hurricane still has about the same amount of destructive power, it is just spread out over a larger area. This tends to increase the hurricane's storm surge, but lessens the wind damage, since the extreme winds of the inner eyewall are no longer present. Satellite loops show a large, well-organized storm with increasing amounts of low-level spiral bands forming, and improving upper-level outflow. Data from last night's flight of the NOAA jet showed an unusually moist atmosphere surrounds Alex, so dry air is no longer a problem for it. It's a good thing Alex has less than a day before making landfall, or else is would be a large and very powerful major hurricane.


Figure 2. Visible light image of Tropical Storm Alex taken at 19:35 UTC (2:35 pm CDT) on June 29, 2010, by NASA's Aqua satellite. At the time, Alex was a tropical storm with 70 mph winds. Image credit: NASA.

Storm Surge
Traditionally, a storm's ranking on the Saffir-Simpson Scale--the familiar Category 1, 2, 3, 4, 5 rankings we always talk about--have also been used to quantify storm surge threat. However, large, weaker storms that cover a huge area of the Gulf of Mexico, like Alex, can generate a larger storm surge than a smaller but more intense hurricane with a higher Saffir-Simpson rating. Thus, the National Hurricane Center has formally discontinued use of the Saffir-Simpson scale to characterize storm surge, and is studying the possibility of issuing separate Storm Surge Warnings a few years from now. These would be in addition to their traditional Hurricane Warnings. To give us a better idea of a storm's surge potential, Dr. Mark Powell of NOAA's Hurricane Research Division has developed the Integrated Kinetic Energy scale to rank storms. The scale ranges from 0 to 6, and a parallel wind damage scale that runs from 0 to 6 is also generated. Alex had an Integrated Kinetic Energy of 2.6 on the 0 to 6 scale at 1:30pm CDT yesterday, and its destructive potential rating for winds was just 1.2. Thus, Alex's surge ranked alomst one-and-a-half categories higher in destructive potential than its wind. These numbers have probably increased by a full category since yesterday afternoon. NHC is giving a 40% - 60% chance of a storm surge of at least 3 feet affecting the Brownsville area, and 10% - 30% chance the surge will exceed 5 feet. In theory, a Category 2 hurricane moving WNW at 5 mph can bring a storm surge of up to 8 - 9 feet to the South Texas and northern Mexican coast.

Other Impacts
Alex is bringing bands of heavy rain to the coasts of Texas and Mexico, as seen on the Brownsville, Texas radar. Hurricane local statements with projections for how Alex will affect the coast are now being issued by the National Weather Service in Brownsville and Corpus Christi. Flooding damage from the expected 6 - 12 inches of rain from Alex will be the main concern. Wind damage is a lesser concern, since the core of Alex is making landfall in a swampy, sparsely populated region of Mexico. The combined wind, surge, and flooding damage from Alex may be similar to 2008's Hurricane Dolly, which hit near Brownsville. Dolly was a Category 2 hurricane offshore that weakened to a Category 1 hurricane with 85 mph winds when it made landfall, and did about $1 billion in damage. Dolly also generated two weak EF-0 tornadoes, and Alex is capable of generating a few tornadoes as well, according to the latest discussion from NOAA's Storm Prediction Center. The atmosphere is moderately unstable, there is plenty of moisture, and wind shear at low levels has been increasing this morning. The greatest threat for tornadoes will occur late this afternoon, on the right side of where the storm makes landfall.

Alex in historical context
Alex is the first June hurricane since Hurricane Allison of 1995. Allison briefly became a minimal 75 mph hurricane before weakening and hitting the Florida Panhandle as a tropical storm. Alex is the strongest June hurricane since Hurricane Bonnie of 1986, which had 85 mph winds. Bonnie was the first hurricane I flew into as a member of the Hurricane Hunters. Bonnie made landfall along the upper Texas coast, and caused less than $20 million in damage. If Alex strengthens to 90 mph winds, it will be the strongest June hurricane since Hurricane Alma of 1966, which had 125 mph winds as it skirted the Florida Keys. There have been only ten hurricanes in May or June since 1945; only four of these were major Category 3 or higher storms.

Track forecast for Alex
All of the models take Alex to the west or west-northwest into northern Mexico by early Thursday morning. However, the steering currents are fairly weak, and Alex could stall and move erratically at times today. I don't anticipate that this weakness in the steering currents will allow Alex to move northward and make landfall in Texas. After landfall, the ridge of high pressure forcing Alex westward should remain in place and strengthen, keeping Alex's remnants over northern Mexico for several days.

Intensity forecast for Alex
Alex is over a region of ocean with moderately high total ocean heat content . Wind shear has fallen to a low 5 knots, and is projected by the SHIPS model to remain in the low range, below 10 knots, through landfall. The combination of low wind shear, moderately high ocean heat content, and plenty of moisture should allow Alex to continue to intensify today. Alex's pressure is already characteristic of a Category 3 hurricane, but the storm is so large that it is taking time for the winds to catch up to the pressure falls. It is unlikely that Alex's winds will be at Category 3 strength at landfall, since the storm is undergoing an eyewall replacement cycle, and does not have time to build a tight inner eyewall with strong winds before landfall. A Category 2 storm at landfall looks more likely.

Elsewhere in the tropics
The latest run of the NOGAPS model predicts the formation of a tropical disturbance in the Western Caribbean on Monday. None of the other models is showing anything brewing over the coming seven days.

Wind and ocean current forecast for the BP oil disaster
Alex is generating very rough conditions over the Deepwater Horizon blowout location, with 6 - 8 foot waves and 3 - 4 foot swells. Strong southeast to south winds of 15 - 25 knots will blow over the oil slick region today through Thursday, according to the latest marine forecast from NOAA. The resulting currents will push oil to many protected bays and estuaries that haven't seen oil yet. In addition, the 1 - 2 foot storm surge Alex is generating along the Louisiana coast will act to push oil deep into some low-lying marshlands. While this oil will be diluted some by the wave action, the impact of the oil and accompanying toxic dispersants on the marshlands is of concern. The latest trajectory forecasts from NOAA and the State of Louisiana show oil will also move westward along the central Louisiana coast towards the Texas border. Winds will decrease to 10 - 15 knots Friday through Monday but remain out of the southeast, keeping the pressure on the regions of coast in Louisiana, Alabama, and Mississippi that are seeing oil hit their shores this week.

Resources for the BP oil disaster
Map of oil spill location from the NOAA Satellite Services Division
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 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

Next post
Either Rob Carver or myself will do an update late this afternoon or this evening.

Jeff Masters

Hurricane Alex (LRandyB)
Weather inbound to Hurricane Alex.
Hurricane Alex
Hurricane Alex (LRandyB)
Weather inbound to Hurricane Alex.
Hurricane Alex
Hurricane Alex (LRandyB)
Flight deck view from a WC-130J Hurricane Hunter aircraft
Hurricane Alex

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1170. That is a cruel tease.. enjoy.. that's one of my favorites.. YUM!
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Quoting sarahjola:
can someone answer this question- could alex ride the coast? thanks in advance:)


I believe that Alex has his eye on Mexico.
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Quoting CybrTeddy:
Alex is north of its forecast points.


Yup, I think StormW's call for landfall 50 to 60 nm south of the Rio Grande is looking good.
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thanks!
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We aren't getting hardly any rain here....kinda surprised...
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1189. JamesSA
Quoting sarahjola:
can someone answer this question- could alex ride the coast? thanks in advance:)
He seems to be headed inland, just with a more Northward trajectory than we expected yesterday.
Member Since: August 17, 2009 Posts: 0 Comments: 579
Member Since: June 9, 2007 Posts: 4 Comments: 15947
can someone answer this question- could alex ride the coast? thanks in advance:)
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Quoting Levi32:
Dry air is really wrapping around the core....the eyewall is nearly completely cut-off from the surrounding spiral bands.

Quoting sarahjola:
could alex ride the coast?

Very very very very unlikely.
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Quoting Patrap:


Then you can follow along the learning cure..

Cuz a Blind Duck in Bangkok can easily see the dry air in the Systems envelope on the south side.




If you understood the process of convection a little more, the factors that favor it, and the factors that go against it, then maybe you would agree with me. Just because convection lacks in that part of its circulation does not mean there is dry air present there, its not that simple. Strong thunderstorms form in the plains in air masses that are relatively much drier then the driest quadrant of Alex. Yet, there's plenty enough moisture to unleash powerful thunderstorms with heavy rain.

While at the same time, we have a very deep tropical air mass over Florida, but yesterday convection lacked till the evening, because convective forcing was too weak and convergence was weak until evening, then convection fired big time.

Tropical cyclones organize lift and convergence in bands and segments throughout the system. There are also areas where the cyclones do not create lift and convergence, thus convection does not develop, this is a normal function of tropical cyclones, having nothing to do with dry air.

There are times where tropical cyclones move into dry air masses, temporarily causing dry air to wrap intro the circulation. However, this is far from the case with Alex, Alex is not surrounded by dry air, so there can't be dry air entrainment in the first place.


What bothers me though, is not people who are ignorant. There can be pure humility in ignorance, in other words, an ignorant person who is willing to actually listen.
However, what bothers me is someone who is ignorant and insists they actually know better.


I won't argue about this with you anymore, cause that's just stupid, and doesn't cause anything but trouble. Also I like keeping peace with others as best is I can.

I just hope you'll consider what I'm saying, and study convective processes a little further.
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1180. angiest
Quoting TexasHurricane:
I see it is moving NW now???


Still looks more west to me.
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1179. Asta
1094:
Yep- me too-
In Betsy, I had a window blow in on me
Camille, went through it in NOLA- still have vivid memories of driving the coast afterwards.
Ivan, Andrew, Katrina - well, we just won't talk about her...Rita & Gustav-and more lesser TDs and street flooding..( lost my bee hive to one of those dang unexpected Downpours!)
and yes- I will run if the storms come -
but I love South Louisiana and the G.O.M. and wouldn't want to be anywhere else.
Getting Rain courtesy of Alex right now.


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Its pretty amazing how the NHC is with the storms. They are really good with the tracking and intensity. Has stayed in the cone the whole way
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Hello everyone !

Patrap I was so tired last night and miss what you said are you leaving?
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Quoting Patrap:
Well..Im gonna go take these 4 Soft Shell crabs and dust dem off with some flour, tozz um in sum egg an tabsaco wash,den dredge um thru some Corn Flour and seasoning, and den chuck um in a Pot of 355 degree cottonseed oil.




Be back later gators..

Where my tongs?



Pitch in a cupla more. I'm right over.
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I see it is moving NW now???
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Port isibel is flooded oz is in the water
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1172. angiest
Too bad Brownsville doesn't have a terminal doppler radar. That would probably look good now.

Recent base velocity:

velocity 4
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1171. Levi32
Interesting presentation in the latest image with the eye clearing out a tad but dry air wrapped all the way around the core, cutting off the eyewall.

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1170. Patrap
Well..Im gonna go take these 4 Soft Shell crabs and dust dem off with some flour, tozz um in sum egg an tabsaco wash,den dredge um thru some Corn Flour and seasoning, and den chuck um in a Pot of 355 degree cottonseed oil.




Be back later gators..

Where my tongs?

Member Since: July 3, 2005 Posts: 427 Comments: 129449
Alex is north of its forecast points.
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1168. NRAamy
GoodOleBudSir....always happy to see you on here....


:)
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1167. Levi32
NASA loops are finally back up and running. I set up a floater link for you guys.

High-resolution rapid-scan visible loop of Hurricane Alex
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Quoting sarahjola:

it was getting squeezed early this morning. still happening. anyone have a current steering map? thanks in advance:)


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Quoting skepticall2:


He told me he made fun of an admin which is a no no


He hijacked the blog to promote his own interests among other things.
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Back for another season. Greetings form my little corner of the Gulf ;)
Rainy day here, some wind. Alex is running out of time and space I hope.
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While I'm not as cool as Oz with his realtime video, I am chasing in Brownsville (2 miles north of downtown) and since 1pm cdt the highest winds i measured were 08022G28+RN. I'll be out every 15 min for 15 min =)
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i live on the mid texas coast bout 70 miles inland and we been getting plenty of the wet stuff. i just dumped out another inch since this morning. not too much wind, just plenty of rain as the bands come in.
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1161. JamesSA
Quoting Levi32:
The 1pm advisoroy updates position not track. The track won't look like that at 4pm CDT when they update it.
When it is that badly busted so near to landfall in a populous area they need to make some adjustments based on observed reality. This may be protocol, but such a misleading projection puts people in danger.

They shouldn't put out an advisory suggesting to people that it is about to turn around and go back to Mexico when just the opposite has happened. Sheesh!
Member Since: August 17, 2009 Posts: 0 Comments: 579
1160. Levi32
Quoting RCThunder:
What is up with that NHC track?


Intermittent advisories like the 1pm do NOT update track. They update position and current intensity....track and intensity forecasts are not updated until the complete advisory at 4pm.
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Quoting CaneWarning:
What did Oz do to get banned?


He has been banned for a few weeks.
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What is up with that NHC track?
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Member Since: June 9, 2007 Posts: 4 Comments: 15947
Quoting Levi32:
Blog updated.

Tropical Tidbit for Wednesday, June 30th, with Video


Thanks, Levi. Good info with sound advice as well.
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Pretty much all of central texas under a flash flood watch until 7pm Thursday.
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People are mad at oz about the whole cigrite thing
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as you can see that didnt turn out too good neither
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Quoting Patrap:
Life is about choices.

I made a bad one in Aug 2005 and got Lucky.

But I saw many,..sadly who made the same decision,and werent able to say so.

Only 1 mile east of me.

Ill never make that bad decision again.

Ive learned hard.


You stayed Patrap through Katrina!! She was bad enough inland where I live. Stood out under a large metal structured carport the whole time watching. The wind and rain was tough.
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1148. Patrap
Quoting midgulfmom:
Pat.. Oh my...we had a camp(Katrina got) on the back bay of Pass Christian and I always begged my parents to stop at Louise's with the pile of shells. BTW we are the same age. Go figure.


Kewl stuff.



Love da beach and used to dine at Annie's a Lot in da summa.
Member Since: July 3, 2005 Posts: 427 Comments: 129449

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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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