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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2698. centex
Sat people are running behind those watching radar.
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this storm is making landfall now...
and it looks strong.
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2696. leo305
Quoting Stormchaser2007:


Pressure/ADT-Yes
Winds-Not close



it's almost CAT 4 pressure wise..

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2695. Drakoen
Very impressive storm:

Member Since: October 28, 2006 Posts: 57 Comments: 29888
BRO: Brownsville [Cameron Co, TX] nws employee reports HURRICANE at 07:28 PM CDT -- nws employee reports widespread power outages in city of brownsville.
Member Since: January 24, 2010 Posts: 0 Comments: 529
Quoting Stormchaser2007:
Franklin is on TWC

Didnt mention anything about an upgrade.


Franklin in my opinion has sour grapes, he led the ouster of Proenza from what I gather and wanted to be Director , he's a man with a chip on his shoulder from what I gather.
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2691. Becca36
Quoting JLPR2:
I'm really impressed O_O

What a beautiful storm!
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2690. Patrap
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Quoting MiamiHurricanes09:
Impressive tropical wave...




and here comes 95L
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Quoting futuremet:
This is clearly a category 3 Hurricane.
I've been thinking that all day...
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting futuremet:
This is clearly a category 3 Hurricane.


Pressure/ADT-Yes
Winds-Not even close

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Impressive tropical wave...

Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting neonlazer:
Franklin is the lead forcaster for NHC, if he says its upgraded..its upgraded lol



hmmm thats bill reed
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Quoting Tazmanian:



thats nhc not TWC TWC cant upgrade any thing with out the nhc OK


Franklin works for the NHC. He just made an appearance on TWC
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Franklin just stated it is 25 miles away from the coast and moving at 12mph. As he put it "do the math". 2 hrs until official landfall, which he listed as the center crossing the coast. I always thought landfall was when the leading edge of the eyewall hit land.
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After all of the debate this morning as to wobbles to the North, even afer NHC/Lixion Avila pretty much stuck to their guns on their forecast track with landfall in Mexico, KUDOs to NHC and their track forecast...............
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This is clearly a category 3 Hurricane.
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2679. bassis
Brownsville, Storm Total Surface Rainfall showing 11 in in places
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BRO issues Flash Flood Warning for Cameron, Hidalgo [TX] till 11:15 PM CDT
Member Since: January 24, 2010 Posts: 0 Comments: 529
Quoting centex:
No more upgrades it's stated to cross.

not yet but close
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Its 5 o'clock somewhere.
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Quoting Patrap:
You're the Storm

The Impact of the eyewall begins ..

Best of Faith and Luck to those dancing in the Beast tonight


Well put Patrap. Having lived through it myself a few times it hits home and my prayers go out to those in the path of Alex tonight, be safe.
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Quoting Tazmanian:



thats nhc not TWC TWC cant upgrade any thing with out the nhc OK
Franklin is the lead forcaster for NHC, if he says its upgraded..its upgraded lol
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Quoting angiest:
Eyewall starting to look ragged. Maybe feeling the land?


Eyewall is looking better, notice the expanding yellow colors and some reds in the radar. Thats a sign of a deepening eyewall.

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2672. Asta
Quoting PcolaDan:


This is going to be worse than the storm surge vs wind driven water vs flooding argument.

Gotta laugh or it will make y'a crazy-
Maybe now when we board up our homes we should also wrap it with Saranwrap too! LoL!
unreal.
Alex's eye still peeking just outside the coastline..


Member Since: July 4, 2008 Posts: 30 Comments: 1024
Tend to agree Big Al will be re-analyzed as a cat 3 in the post storm analysis at seasons end. Dvorak T #'s were at 6 a bit earlier which actually indicates a borderline cat 4. Probably has another 2 hours to strengthen. I say 125mph winds upon re-analysis and that they will also re-analyze Alex as a hurricane at Yucatan landfall and over the Yucatan. Amazing storm and this is only June!!!
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2670. angiest
Quoting Hurricanes101:


????



I'm watching the radar. The western eyewall is losing the yellows and oranges.
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Quoting weatherwatcher12:

It is June. It's June 30th.

Not in UTC. It's 0027, July 1st.
Member Since: August 2, 2006 Posts: 46 Comments: 11666
Quoting SiestaCpl:


Exactly so...the obvious line at BP could be the oil is hasardous waste that we pay for..the ruined drywall (unless it is Chinese drywall...) is the problem of the insurance company...who have no said they will not cover it...Wife has many years in FL in that field...


Tempted to sell my house a get a motor home. :)
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Quoting weatherwatcher12:

It is June. It's June 30th.


Whats the date say? Its July now.

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Quoting AstroHurricane001:


Too bad it won't set a June record, because it's July.



70 minutes? Looking more like 150 minutes, per my latest estimate.



Looks like it basically followed the southern end of the white cone.


That's what I asked about 30 minutes ago :) Would the NHC use local time or Z time when deciding if it was June or July? =) =)

Ok back out in it for a bit
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I sure do hope Oz stays safe with his baseball and hockey gear. No doubt he is prepared! Eek!
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2664. centex
No more upgrades it's stated to cross.
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Quoting Stormchaser2007:
Franklin is on TWC

Didnt mention anything about an upgrade.




thats nhc not TWC TWC cant upgrade any thing with out the nhc OK
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Quoting AstroHurricane001:


Too bad it won't set a June record, because it's July.



70 minutes? Looking more like 150 minutes, per my latest estimate.



Looks like it basically followed the southern end of the white cone.

It is June. It's June 30th.
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Quoting Stormchaser2007:
Franklin is on TWC

Didnt mention anything about an upgrade.



Seemed like they're gonna keep it at 100 mph.
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Quoting WPBHurricane05:


LOL

Maybe the catchers gear too as an added bonus.

lol that was a waste of 40 mins of my life
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2659. JLPR2
Something is wrong here:

XD
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Franklin is on TWC

Didnt mention anything about an upgrade.

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Quoting PcolaDan:


This is going to be worse than the storm surge vs wind driven water vs flooding argument.


Exactly so...the obvious line at BP could be the oil is hazardous waste that they (BP) pays for..the ruined drywall (unless it is Chinese drywall...) is the problem of the insurance company...who have now said they will not cover it...Wife has many years in FL in that field...
Member Since: June 26, 2008 Posts: 0 Comments: 379
Quoting angiest:
Eyewall starting to look ragged. Maybe feeling the land?


????

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Quoting Stormchaser2007:
Didnt see anything on recon to upgrade it to a Cat 3.

Maybe to 110mph. But thats all.
The 948mb vortex message reading might take it to category 3 intensity, but it isn't guaranteed.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Inre 2565, PcolaDan, lest people get misinformed...
Admittedly Mexico has its own touchiness about its neighbors to the north, but I don't think that extends to research overflights by hurricane hunters.
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2653. angiest
Eyewall starting to look ragged. Maybe feeling the land?
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My prayers and thoughts are with those in Alex path, nothing dangerous as strenghtening landfalling hurricane, I have a feeling the aftermath of Alex will be much worse than previously expected, I honestly hope I'm wrong!
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Member Since: September 2, 2009 Posts: 130 Comments: 21091
Someone was asking about lightning, or the lack of, in hurricanes. I found the following on NASA:

“Actually, says Blakeslee, the reason most hurricanes don't have lightning is understood. "They're missing a key ingredient: vertical winds."

Within thunderclouds, vertical winds cause ice crystals and water droplets (called "hydrometeors") to bump together. This "rubbing" causes the hydrometeors to become charged. Think of rubbing your socked feet across wool carpet--zap! It's the same principle. For reasons not fully understood, positive electric charge accumulates on smaller particles while negative charge clings to the larger ones. Winds and gravity separate the charged hydrometeors, producing an enormous electric field within the storm. This is the source of lightning.

A hurricane's winds are mostly horizontal, not vertical. So the vertical churning that leads to lightning doesn't normally happen.”

The same article also noted that the electric field above Emily, as recorded by instruments on NASA’s ER-2 (U-2), were about 8 kilovolts/meter. Quite a strong field, indeed. They noted this was, indeed, an anomaly.


Link

Very Respectfully,

Jon
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2649. russm1
Quoting Clearwater1:
Any insurance agents care to field this question?
If a storm is labeled a "Tropical storm" when it hits your home, does your deductible fall under the category of simply wind damage? Conversely if it is labeled a "hurricane" will you be forced to use the "hurricane" deductible. Big cost difference. (at least in FL) The reason I ask, is because if what I mention is true, then it is very important in marginal storms as to how they are labeled coming inland. Anyone?


It must be a hurricane when it hits land for the hurricane deductible to apply. If it is a hurricane over water then degrades to TS before it hits land then it is a wind event. It it only obtains TS status and then hits land it is considered a wind event.

Hope this helps!!
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Didnt see anything on recon to upgrade it to a Cat 3.

Maybe to 110mph. But thats all.
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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.