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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Member Since: July 3, 2005 Posts: 426 Comments: 129093
The RUC 15z 500mb analysis reveals that Alex is west of the trough axis and the primary steering for the system is now the ridge centered over the Central Plains region. Alex will begin to turn more the WNW as a result of the ridge's influence.

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he just got lucky...lol....haha...is he would have panicked and sunk the tires in deep, i don't know if he would have gotten help before the water came in...
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Quoting watchingnva:
he just got himself stuck on the beach....geez...


Oz is crazy. LOL
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i think its going to tighten like a huge slingshot and then zinggg and jump under the trough, turn around, and have a beta affect.
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593. xcool
kmanislander .:0
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592. jpsb
Quoting LaCoast:


Really? Wow! Look out Galveston.....sheesh come on man, get real!!
Sitting here watching my barometer holding steady at 29.9, well after tapping it, it's down a tiny tiny little bit.
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Have you been able to reach him yet??
Quoting PensacolaDoug:
Tryin to call OZ.
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Quoting watchingnva:
he just got himself stuck on the beach....geez...
Ohh, been there...beaches don't let go once you're digging a rut.
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589. IMA
Quoting GBguy88:


This person with the issue of being at work until 5...maybe they aren't able to leave at will due to the potential loss of a job. Yes, it's a bad situation to be in, but consider the employer when someone says "You're making a bad call, I'm leaving." That warrants a termination from a lot of bosses. Not really worth it for a less than major hurricane if you don't have another job on hand.

My biggest concern for this person is the flooding issue (though "a less than major hurricane" still packs a punch, especially with a lot of the types of structures found in Matamoros). You have no idea how easily it floods in Matamoros!
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Quoting DestinJeff:
1500 CIMSS:



Yep, see my post 569
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Quoting AussieStorm:
CycloneOz has encountered storm surge at his present location. He's at the border, on the GOM


That sounds like a lot of fun! I love going to the coast when systems are out there. I wouldn't advise it though.
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he just got himself stuck on the beach....geez...
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Photobucket

The cone goes from just north of Brownsville just in case it continues this whacked NW motion, and about just north where the NHC/models track it, if the storm suddenly makes a sharp westward turn, which is looking unlikely. After clicking another frame of the visible on RAMSDIS, the eye continues to move NW. If the NW motion continues for the next 2-3 hours, my current forecast track will even be south of the actual track of Alex. Brownsville, Texas needs to closely watch this storm for any deviations in movement, I really hope the southward forecasts of the models and the NHC didn't stop people from preparing for the storm.
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I wonder when NHC is goint to adjust those trops Fcst points since they are so far out from the actual COC.
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Quoting Hardcoreweather2010:
The problem with his stream is he is doing sound. If he killed that it would look 50% better . Now back to Alex

dman he is stuck!
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CycloneOz has encountered storm surge at his present location. He's at the border, on the GOM
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The problem with his stream is he is doing sound. If he killed that it would look 50% better . Now back to Alex
Member Since: January 24, 2010 Posts: 0 Comments: 529
Oh that's awesome! Thanks!
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Quoting weatherboyfsu:
If I lived in Brownsville, I would not be anywhere near the coast....and that goes for about 50 miles north of there! Move inland 5 miles or so.... Things are going to change as they always do but brownsville area is not out of the woods by no means.... If Alex continues to move more NW, that would mean more time to strengthen.....Also the strongest part of the storm is on the right side meaning the northern side in this case. Boy,,,,,,,i wish i were in Brownsville right now!!!!!!!!!!!


I wish I were there too. If you are inland in a steady building there shouldn't be any problems unless rain causes flooding.
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im starting to wonder if ustream can handle 130+ viewers...whats the most that any of you guys know hes got up to in viewers...
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Had a wild early morning. Had an insanely strong early morning Thunderstorm.
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Does anyone have any links to Southern Texas/Northern Mexico stations?

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Quoting IKE:
Stephanie Abrams....mellow out mam.....


What did she do?
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So Alex is about to go north of all the model tracks once again?? He's so dang rebellious!! LOL
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Quoting KingofNewOrleans:


Brownsville is actually about 15 miles inland. I don't know know what the closest coastal station in NE Mexico is.

There are stations at Brownsville, South Padre, and Port Isabel. Those will be the closest to the coast.
Member Since: August 2, 2006 Posts: 46 Comments: 11683
Morning everyone, just got back from our quarterly EOC meeting, our new NWS meteorologist spoke on updates to there prediction capabilities "Our wind forecast models showing as an example a predicted 110mph winds can be off by as much as 20% +/-", i thought was kind of a scary disclaimer, because it could mean a jump up or down in category of hurricane just a n fyi, back to lurking
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Latest steering shows the ridge has relaxed some more and now oriented SE to NW across the Texas area. WNW may no longer be possible given the strength of the system.

Gohere and toggle between current steering and 3 hours ago. You can see the high lift to the N above Texas.
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If I lived in Brownsville, I would not be anywhere near the coast....and that goes for about 50 miles north of there! Move inland 5 miles or so.... Things are going to change as they always do but brownsville area is not out of the woods by no means.... If Alex continues to move more NW, that would mean more time to strengthen.....Also the strongest part of the storm is on the right side meaning the northern side in this case. Boy,,,,,,,i wish i were in Brownsville right now!!!!!!!!!!!
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Quoting atmoaggie:
Why is the difference of 60 miles for a landfall point so important to so many in here? This is a broad storm with multiple wind maxima, radially. A few miles here or there isn't going to mean anything different transpires. That would be like saying Ike didn't cause any problems in Bridge City.

This isn't Marco, or even, Felix.


Alex is larger than Dolly, probably larger than Ike.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
thanks atmoaggie
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564. IKE
Stephanie Abrams....mellow out mam.....
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Yay, Oz is back. Too funny.
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Not paralleling the coast. Heading towards it:

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Why is the difference of 60 miles for a landfall point so important to so many in here? This is a broad storm with multiple wind maxima, radially. A few miles here or there isn't going to mean anything different transpires. That would be like saying Ike didn't cause any problems in Bridge City.

This isn't Marco, or even, Felix.
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Quoting Bayside:
Does anyone have streams of local new stations setup? Just curious, during some of the other storms like Ike people had these news streams up and I could access them from work.


Pretty cool live stream here.

Afternoon all
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Quoting PensacolaDoug:




Its entertaining



Hes back on






Nice to see first hand what is happening back home.
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Quoting txalwaysprepared:
Question:

Should I worry that this line of storms headed right for me has a mesocyclone mark on it? (R9)


A mesocyclone indicates the possibility for a tornado. I have had a few of those narrowly miss my location, but not all of them produce tornadoes. Regardless, take immediate cover if you see threatening weather approaching.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
Quoting Chucktown:


That high is still building down and moving SE. NHC is right on this - expect a sharp turn to the west as we go through the day. Northern fringe of the eyewall make scrape Brownsville.


Actually the storm is off the the models and NHC track.
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upstream is back up
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I am a chaser and stream all the time and you will have to just stay calm waiting on OZ's stream cause even streaming in the USA you are going to have places with no data. I even have an amp and external antenna and still have dead spots. I can just imagine how much worse it is in MX
Member Since: January 24, 2010 Posts: 0 Comments: 529
Quoting snotly:
Good burst of intensification. Maybe up to 100mph by 2pm update


Maybe I need my eyes checked, but close-up on the eye seems to be showing some degradation of the southwest eyewall.
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just got him back....lol...
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Does anyone have streams of local new stations setup? Just curious, during some of the other storms like Ike people had these news streams up and I could access them from work.
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Quoting Drakoen:
Looks like it wants to turn more towards the WNW


Looks to Like the Parallel for now Drak..


Brownsville is gonna take a wacking.
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting txalwaysprepared:
Question:

Should I worry that this line of storms headed right for me has a mesocyclone mark on it? (R9)


Yes.
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Quoting PensacolaDoug:
Tryin to call OZ.

he is back, tell him to take cover.
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The long term motion however is NW
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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.