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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2998. angiest
Quoting Patrap:


SW drift again.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
2997. Patrap
One paper ,,or one in the works tells of the Vortices within a Strong Eyewall,..concentric,..act Like Spokes on a Rim that keep the Symmetry in Harmony by some yet undetermined process.
Member Since: July 3, 2005 Posts: 414 Comments: 125476
2996. MZV
Looks like Alex threw a "right hook" of heavy reflextivity directly on that island, just as he landed.
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2994. USSINS
I wish no harm to anyone near or distant from this storm's effects, but had Alex had more time over water or shot up through the channel early on, I'm afraid this would have been a mega-monster and extremely devastating.

One person's life is devastating and sad if lost due to the storm as far as I am concerned. I just know it could have been much, much worse.


Alex has been so massive. I left the beach today, headed north, and honestly could not see to drive at one point for the rain and pulled into a rest area until it lightened. Truly unreal, anytime, but especially for a June storm.
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Hopes and prayers to all those who lose property and/or loved ones with this storm - both in the US and in Mexico.

From a chaser's perspective, this was a great practice run. Got some good winds, enough adrenaline to last a good solid few weeks... but I am absolutely beat. Since not much more is likely to happen in B-ville that I haven't already recorded, I might call it a night and catch some z's.

For any future chasers out there, here's what I've learned in my six hurricanes:

1. Always plan for the worst case scenario
2. Always leave yourself at least two "outs" in case one gets blocked.
3. Pack more than you need.
4. Take lots of towels and dry clothes - and more than one pair of shows
5. Goggles and/or safety glasses if you're gonna be out in it. 20mph wind + rain can really sting - let alone 60 or 70 mph!
6. Pick a place that gives the most protection for your vehicle and you! You need both to get out.
7. Pick a place that has lots of open space in the direction of your expected prevailing winds... this will give you the most accurate readings and reduce the amount of debris flying at you.

There's more but this post is already too long :) You guys all rock! The experts in here likely save lives... and help folks like me be as safe as possible. =)
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So the landfall location was a good case scenario right? Even with a stronger storm, better than if it had landed more north?
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2991. BDAwx
Quoting P451:


Most likely the storm has tightened up rapidly as it approached land.

Time and again systems rapidly strengthen as their cores tighten up in response to approaching a north/south oriented coastline from the east.

This is not an anomaly. This is a frequent occurrence in this region.

While yes there is likely debris all through the storm that the radar is also reflecting - what you are seeing is the storm rapidly tightening up and intensifying in response to the land mass.



true.
I mean, I only mention it because only the western eyewall suddenly had higher reflectivity as soon as it went over the barrier island.So I thought there might have been some sort of correlation, but hey - for all I know the island could be completely underwater!
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Quoting scott39:
Is CMC a good model?


Only for long-term track forecasts.

Quoting hurricaster:
Remnants, remnants, remnants. Any thoughts on the "land track"?


One layer drifts over the Bay of Campeche and drags in some convection that moves toward Louisiana, while another layer stalls over the Mexican mountains. It soon moves over New Mexico, then eastward and briefly stalls over Missouri, causing severe flooding along the Mississippi River. It undergoes an estratropical transition, and while doing so ejects some moisture oer the northern Gulf. The moisture combines with the convection from the BOC low and drifts over Florida, the develops into a subtropical storm over the Gulf Stream. Meanwhile, the remnants of Alex drift northwards, worsening the flooding and merging with thunderstorms from a cold front. As this occurrs, it releases flooding rains over the Great Lakes basin. The low in the BOC soon sends another tropical storm into the Yucatan channel, before it drifts into the East Pacific, combining with ICTZ moisture and developing into a large hurricane that eventually sends another wave into the Gulf of Mexico, developing into a tropical storm as it hits the Florida Panhandle.
Member Since: August 30, 2008 Posts: 8 Comments: 2834
2987. Patrap
Member Since: July 3, 2005 Posts: 414 Comments: 125476
2986. leo305
NHC expects center to make landfall in half an hour to an hour
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Quoting P451:
100mph Landfall is this correct?

Pretty much felt 105 if northern mex and 115 if southern texas.

I see Alex did tighten up as it approached the coast - which has happened before with many storms.

In the end the models of 4 days ago were pretty good with this system. GFS was out to lunch but the rest really had the track pretty well done. 4 days out you're going to have errors but they had the general behavior and movement correct. They pegged the odd behavior upon exiting the YUC although none saw it lasting a full day. From there they had the northerly component followed by the westerly component. While they didn't anticipate such a sharp turn to the west and most models had the system hitting southern most Texas again they had the general behavior down. Four days out what do you expect? They did very well...and so did the pro mets in regards to the system from it's inception as 93L in the ECar to not expecting development until it hit the WCar.

It's encouraging!

Even the long range models from 2 weeks ago hinted at development - albeit it they had it hitting the northern central gulf - but they still picked up on a developing disturbance becoming Alex.

Again, encouraging.

As for "everyone eating crow" that is an incorrect statement. Quite a few individuals had this storm pegged from even days ago. Again, you'll have your errors in exact location and strength but for the most part several folks on this blog did a good job with their opinions on this storm.

Well, all that aside, here's 12 hours of Alex, IR loop, ending 845PM ET, 30 minute increments per frame.


12 hours of radar, too.
I thought it cool, anyway.

Quoting atmoaggie:
12 hours of Brownsville radar. 117 frames.
Not the for the feint of memory, CPU, or bandwidth.
Java loop.

http://rap.ucar.edu/weather/radar/displayRad.php?icao=KBRO∏=bref1&bkgr=color&endDate=2010 0701&e ndTime=-1&duration=12
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Quoting mtyweatherfan90:


Another victim:

Link

Video from live feed at Monterrey reporting floods and rivers (in spanish, but images can give a clue):



Keep you posted...
Raining as hell...


Google translate, spanish to english - Bricklayer fell on a fence.

Link

And a general overview of storm preparations from MX.

Link
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Kissing the coast, 15 minutes ago

Member Since: August 19, 2006 Posts: 0 Comments: 15671
2982. Patrap
If you Look at the last radar Image the Vortexes are dancing ALEX's eye tonight ..
Member Since: July 3, 2005 Posts: 414 Comments: 125476
Luckily the winds never caught up to the pressure.

Could have been a Cat 4.

Im out.
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2980. IKE
NHC puzzled that the winds never caught up to the pressure.
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947 mb on the last dropsonde. 100 mph winds... 1mb shy of audrey.

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Looks like we have landfall, at least on the barrier islands, such as they are.

Link
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Quoting MZV:
So.... what happened to all the wishcasters telling us it'd go northeast to LA/MS/AL? Hmph.
Well, one of them has admitted that he is eating crow...not sure where the rest are...
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2975. Patrap
Member Since: July 3, 2005 Posts: 414 Comments: 125476
2974. KEEPEROFTHEGATE (Mod)
01L/H/A/C2
OVERLAND
FINAL MARK
24.3N/97.7W
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2973. leo305
Quoting P451:


Haven't been in much today.

What record are you alluding to?



The record of being the strongest Hurricane ever in June!
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2972. angiest
Quoting P451:


Haven't been in much today.

What record are you alluding to?



Hurricane Audrey, most intense June hurricane on record.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting RecordSeason:
Alex has cooled the water enough to lower the average intensity rating by about 1 full color ring in many places throughout the gulf and Caribbean, though there are still some extremely hot spots near LA.

Potential Intensity Map
And we don't have many measurements of SSTs yet where it has been cloudy for days and days. Could have a bigger effect than that will show just yet. (unless it is exclusively fed microwave sensor data)
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Quoting P451:


Haven't been in much today.

What record are you alluding to?

Lowest pressure recorded in a hurricane in June.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
2969. leo305
So the peak strength:

HURRICANE ALEX
CATEGORY 2
100MPH 947MB

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2968. angiest
Quoting BDAwx:
could higher reflectivity in the western eyewall be due to debris? eg. leaves and sand.


You can see stuff like that in EF4 and higher tornadoes, but I don't think you can get that in something with such comparatively low winds.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
bunkered down in Brownsville. Winds have picked up considerably in the last couple of hours. Still have power.. yay! Flooding has been extensive both in Brownsville and across the border in Matamoros.


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2966. MZV
So.... what happened to all the wishcasters telling us it'd go northeast to LA/MS/AL? Hmph.
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2964. hydrus
Quoting WPBHurricane05:
Most of the time, the only light flashes seen in a hurricane are transformers blowing.
Thats true for me too. The Tropical storms I have been through I have witnessed a lot of lightening. Been through five hurricanes and only one(Charley)had lightening at the location I was at. Transformers were exploding all over the place.
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2963. BDAwx
could higher reflectivity in the western eyewall be due to debris? eg. leaves and sand.
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2962. Mikla
Official forecast (OFCL) versus actual path starting June 27 00Z...
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2961. angiest
Quoting angiest:
Vortex came out with 947mb.


And a closed, 12nm circular eye.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
2960. Patrap
Tornado Watch

Statement as of 8:07 PM CDT on June 30, 2010


The National Weather Service has issued Tornado Watch 433 until
4 am CDT Thursday. Tornado Watch 430 has expired. The new watch
is valid for the following areas

In Texas the new watch includes 5 counties

In deep south Texas

Brooks Cameron Hidalgo
Kenedy Willacy

This includes the cities of... Brownsville... Edinburg...
Falfurrias... Harlingen... McAllen... mission... Pharr...
Raymondville... Sarita and Weslaco.

Tornado Watch

Statement as of 8:07 PM CDT on June 30, 2010


The National Weather Service has issued Tornado Watch 433 until
4 am CDT Thursday. Tornado Watch 430 has expired. The new watch
is valid for the following areas

In Texas the new watch includes 5 counties

In deep south Texas

Brooks Cameron Hidalgo
Kenedy Willacy

This includes the cities of... Brownsville... Edinburg...
Falfurrias... Harlingen... McAllen... mission... Pharr...
Raymondville... Sarita and Weslaco.


The threat for outer band tornadoes continues overnight as Alex
continues into northeastern Mexico. Conditions remain sufficient
for a few more tornadoes across the lower Rio Grande Valley north
to the King ranch.

Remember... tornadoes are difficult to detect at night especially
with heavy rain. If warnings are issued... do not try to confirm
them visually! Seek safety in a sturdy building immediately. If
you own a NOAA Weather Radio... be sure to place it in alert Mode
before retiring.
Member Since: July 3, 2005 Posts: 414 Comments: 125476
Weather 456, not a regular here but appreciated your input last year. I understand you or a family member has been sick. Hope that situation has improved. Enjoy your posting here
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Alex's lowest pressure is 947mb, 1mb away from tying the record.

000
URNT12 KNHC 010114
VORTEX DATA MESSAGE AL012010
A. 01/00:54:00Z
B. 24 deg 15 min N
097 deg 29 min W
C. 850 mb 973 m
D. 87 kt
E. 093 deg 7 nm
F. 202 deg 82 kt
G. 100 deg 8 nm
H. 947 mb
I. 17 C / 1524 m
J. 23 C / 1507 m
K. 20 C / NA
L. CLOSED
M. C12
N. 12345 / 8
O. 0.02 / 1 nm
P. AF304 1201A ALEX OB 31
MAX FL WIND 107 KT N QUAD 23:37:50Z
;
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting Weather456:
Alex could of easily mirrored his 2004's occurrence.


Instead it mirrored Hurricane Dolly.
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Check out wave in the mid-atlantic.
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2953. angiest
Vortex came out with 947mb.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Thank the lord for land fall. Alex was about to go ballistic.
Member Since: January 30, 2010 Posts: 0 Comments: 3259
Be back in a bit.

Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting CybrTeddy:


Per ECMWF and NOGAPS, that should happen sometime next week.
The 18Z NOGAPS has something July 2nd beginning to form. I think it is the wave at 7N and 30W...
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Just did a blog on Alex.
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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.