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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Quoting MiamiHurricanes09:
If I'm not wrong the NOGAPS developed it and took it to Florida, but that was the 12z run, not sure about the 18z run.
The 18Z NOGAPS has it slightly further south, just north of Puerto Rico heading towards the Bahamas.
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I guess time to move on. Just kidding. So where are the remnants going?
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ALEX is RIP it got in torn up by too march shear MX is safe
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2793. Patrap
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Well, if we don't get a second storm by the first week of july, the odds of getting 16 storms or more, according to records, is slim. This is what I saw on the florida hurricane website.
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2791. angiest
Quoting StSimonsIslandGAGuy:
Ha Ha y'all. It looks like I'll have to wait for Dr. Masters to respond. But it will be a long wait I am sure.

The more and more I look through the advisory archives in the NHC for past storms, and this one--they use EDT, CDT, etc. Not UTC/GMT. Not Miami time. They use the storm's timezone in the advisory archives. It is probably that Alex will be making/have made landfall by the 10 pm CDT advisory tonight.

Which would make Captain Alex a storm landfalling in Mexico twice in June.


Are you looking at the Public Advisory or the Forecast or Discussion?
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Gonna sign off for now but Mexico has such huge problems with corruption and the Drug Cartels now that I hope that aid for the affected folks will not be hindered.....Might want to consider donations to the International Red Cross slated for Mexico if you have the funds.....See Everyone Tommorow.
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2789. leo305
This is going to be it's peak intensity
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2788. scott39
I just want to thank everyone in here who brought clarity to insane moments on this blog. You know who you are! Clap clap clap take a bow.
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2787. snotly
guessing.

landfall at 8pm central
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NOGAPS 18z develops the tropical wave by 10˚N 30˚W.

NOGAPS 18z 132 hours


Member Since: September 2, 2009 Posts: 130 Comments: 21122
Las Carboneras is the village where the 'cane is hitting, tiny fishing shacks, the people were evacuated by the army a few hours ago inland to San Fernando.
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Quoting MiamiHurricanes09:
Recon going to check the eye, again. This is the last pass and will likely be the one used in the 9PM advisory.


This'll make or break the major status.
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need to make sure he stays inland once in, and the trough dont try to shove him back out,,,,whats the ridge looking like?
Member Since: July 14, 2008 Posts: 1 Comments: 9628
A couple of hours old, but impressive nonetheless:

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2780. angiest
Quoting weatherwatcher12:

"Transmitted: 1st day of the month at 00:02Z"


Thanks.
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Quoting HadesGodWyvern:
115 KTS 948 mb

would be a category four if the system was small.


Maybe we should think of Alex as a cat. 4, just one that's been stretched out over an area the size of the Gulf.

Quoting JFLORIDA:


Yea she is - that appears in other places too - I wonder if it is by similar mechanism.


North polar hexagonal cloud feature on Saturn, discovered by Voyager 1 and confirmed in 2006 by Cassini [


Looks like blueberry pie, but that's an interesting storm.

Quoting MiamiHurricanes09:


It's on its way to surpass Ike's minimum Gulf pressure.

Quoting largeeyes:
No gaps has something in the atlantic almost immediately and in the upper islands at the end. What is that?


Quite possibly another ICTZ wave, which is half of what spawned Ike.

Quoting Patrap:




The upper-level eyewall looks displaced to the NW of the lower-level eyewall.

Quoting Stormchaser2007:


I can't even imagine the inland flooding that is going to occur over the mountains of Mexico and Texas.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
Quoting IKE:


I hate to see this season if there is 23 named systems.

Yeah, we're in for a long one.....
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The end of July should be quite a ride. However, think we get a respite for a couple of weeks.
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Your input needed
Link
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Quoting angiest:


Is that current? It does somewhat match what I am seeing on radar.

"Transmitted: 1st day of the month at 00:02Z"
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2774. IKE
Quoting MiamiHurricanes09:
I wonder how btnwtx08 is doing.


I've thought about him....probably without power.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
2773. angiest
Quoting StSimonsIslandGAGuy:


I'm just wondering. Maybe the World Meteorological Organization uses UTC. Because when I look at the NHC advisory archives, the NHC does use the date and time for the longitude the storm is in.

Anyway I asked Dr. Masters. Maybe he'll have time to answer.


Public advisories use local time. All others use UTC. It is Universal, after all. :)
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2772. KEEPEROFTHEGATE (Mod)
LANDFALL

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Recon going to check the eye, again. This is the last pass and will likely be the one used in the 9PM advisory.
Member Since: September 2, 2009 Posts: 130 Comments: 21122
Who has a link to Oz live feed
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SPC issues TORNADO watch till 09:00Z, new watch replaces WW 430 http://www.spc.noaa.gov/products/watch/ww0433.html
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Both 2005 and 2008 both opened in a very similar fashion. Well, you know the rest.
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Quoting nrtiwlnvragn:
May not intensify much further, from the vortex message:

L. Eye Character: Open in the southwest


Based on radar, it sure closed back up in a hurry.

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Typical July tracks:
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Remarkable. Look how Alex is bringing rain all across the estuaries who desperately need it right now to flush them clean.
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Quoting Stormchaser2007:


That wave could develop in the Caribbean in the long range.
If I'm not wrong the NOGAPS developed it and took it to Florida, but that was the 12z run, not sure about the 18z run.
Member Since: September 2, 2009 Posts: 130 Comments: 21122
2763. centex
Quoting StSimonsIslandGAGuy:
It's still June in Mexico

So a question for the knowledgeable bloggers:

When compiling monthly statistics of storms, does the NHC use eastern time (Miami time) or universal time?

Is Alex now in June or July?

It is what it is.
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Quoting MiamiHurricanes09:
I'm focusing more on another wave and not this one. Take a look at the wave by 10˚N 30˚W. That wave is accompanied by an anticyclone aloft and has some decent vorticity.



That is the wave the GFS kept developing in the long range

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Quoting Prolefeed:


So could it be considered a Cape Verde storm, or does it have to be a named storm before crossing a certain longitude to be classified as such?
Nope, it isn't a Cape Verde storm.
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2759. angiest
Quoting nrtiwlnvragn:
May not intensify much further, from the vortex message:

L. Eye Character: Open in the southwest



Is that current? It does somewhat match what I am seeing on radar.
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Amazing storm. This one has been quite a ride. The opening act for 2010 has been nothing short of extrodinary. This storm and pattern portend a very interesting season to say the least. A long, long way to go.
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Quoting MiamiHurricanes09:
I'm focusing more on another wave and not this one. Take a look at the wave by 10˚N 30˚W. That wave is accompanied by an anticyclone aloft and has some decent vorticity.



That wave could develop in the Caribbean in the long range.
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Quoting IKE:


I hate to see this season if there is 23 named systems.


Can you even imagine that? This one storm took up two weeks of watching. No one would ever get any work done.
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Quoting IKE:
Widespread power outages in Brownsville,TX.
I wonder how btnwtx08 is doing.
Member Since: September 2, 2009 Posts: 130 Comments: 21122
Quoting StSimonsIslandGAGuy:
It's still June in Mexico

So a question for the knowledgeable bloggers:

When compiling monthly statistics of storms, does the NHC use eastern time (Miami time) or universal time?

Is Alex now in June or July?




No contest...Alex was a June US Land fall hurricane... Cat 2 at least.
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2752. Drakoen
Quoting StSimonsIslandGAGuy:
It's still June in Mexico

So a question for the knowledgeable bloggers:

When compiling monthly statistics of storms, does the NHC use eastern time (Miami time) or universal time?

Is Alex now in June or July?



GMT
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Quoting WatchingThisOne:


Not GMT/UTC/Zulu it ain't ... we're 30 minutes into July.


So what makes a storm a "June storm"? Can't be landfall because they don't all landfall. I suspect tropical storm status ... naming ... so this would be a June storm. Anyone?
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May not intensify much further, from the vortex message:

L. Eye Character: Open in the southwest

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Quoting Snowlover123:


Ah. Are there favorable conditions ahead of it right now? Because after Alex makes landfall we'll be bored. :)
I'm focusing more on another wave and not this one. Take a look at the wave by 10˚N 30˚W. That wave is accompanied by an anticyclone aloft and has some decent vorticity.

Member Since: September 2, 2009 Posts: 130 Comments: 21122
Quoting Abacosurf:
Always worse to have an intensifying system at landfall.

God bless anyone in his path.



Agree 100%; imagine if this had been an East Coast storm crossing the Gulf Stream just before landfall.....Prayers for the folks in Mexico that will have to deal with this in the coming days.
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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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