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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Alex look better as a cat 2 than most cat 4s
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2297. oakland
Quoting TampaSpin:
Good thing its running out of room...WOW!



My sentiments exactly.
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2296. Patrap
Product: Air Force High Density (HDOB) Message (URNT15 KNHC)
Transmitted: 30th day of the month at 22:58Z
Date: June 30, 2010
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 304)
Storm Number: 01
Storm Name: Alex (flight in the North Atlantic basin)
Mission Number: 12
Observation Number: 50


22:58:00Z 25.083N 96.367W 843.5 mb

(~ 24.91 inHg) 1,425 meters

(~ 4,675 feet) 993.3 mb

(~ 29.33 inHg) - From 130° at 65 knots

(From the SE at ~ 74.8 mph)
Member Since: July 3, 2005 Posts: 428 Comments: 129902
2295. angiest
Quoting HurrikanEB:
Ike made landfall with 953mb and 110mph
Link


Someone posted yesterday that it was revised to 950 at time of landfall.
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Oz talking about Pat on video sitting back in Nawlins
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Hot towers poppin' on the SW side of the eyewall!

Member Since: August 2, 2006 Posts: 47 Comments: 11709
Quoting WPBHurricane05:
It looks like the San Fernando, MX is feeling the west eyewall at the moment. Really not much in the way of cities where Alex is making landfall. Unfortunately, I imagine those small villages are poorer and their homes aren't as sturdy.


Don't forget about the risk for onland flooding! The heavy rain swath from this is seven times wider tan Ike's.

Quoting HurrikanEB:
Ike made landfall with 953mb and 110mph
Link


Alex is now 950 mb and could intensify farther, and it could potentially get up to 110 mph. Alex is larger than Ike. So why is it that when Ike had a storm surge of 20+ ft is Alex's sturge only predicted to be 5 ft?!

Quoting CybrTeddy:
NHC kinda late with the 6 pm. Likely as stunned as we are with the pressure of Alex.


No, they're an hour early lol.
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2291. IKE
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2290. JamesSA
Quoting Patrap:
NEXRAD Radar
Brownsville, Base Reflectivity 0.50 Degree Elevation Range 248 NMI


40 Frame Loop

There is a large southerly component. Interesting.
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2289. Patrap
Quoting Drakoen:
Very impressive to get this strong and well developed of a storm in June.


Yeah, it sure is impressive Drak
Member Since: July 3, 2005 Posts: 428 Comments: 129902
Recon is not leaving yet are they?
Member Since: August 12, 2009 Posts: 0 Comments: 203
Quoting Patrap:
NEXRAD Radar
Brownsville, Base Reflectivity 0.50 Degree Elevation Range 248 NMI


40 Frame Loop





look like Alex is takeing a little Dip too the S in the last few loops
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Quoting sarahjola:
well, the fact is that everybody thought that if Alex sat over water for a long time that he would be a cat. 3, also the pressure drop says different than the winds. while i have been reading for the past 24 hrs. that this should be a cat.2 with the pressure it has. plain and simple that Alex is not as strong as everyone thought it could be given the conditions. my statement was based on what i have read on this blog. as my comment stands it was opinion. i didn't say anything was a fact. i also asked a question. can you talk about why it didn't get stronger than it is right now? thanks in advance:)

it was way past the required cat 3 pressure at the end of the season it will be written in the books as a cat 3
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Quoting StormGoddess:

Frodo is ShireWeatherBuff? Well, well. All the secrets are coming out, now. lol ;)
Anybody got a handle on how the tornadoes or rather hopefully no tornadoes are doing down there?


5 tornado reports so far.

Link
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Quoting HurricaneSwirl:
This is the last advisory before it goes inland.
Doubt it. Landfall will likely be occurring during the time that they issue the 9PM advisory.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Hurricanes101:
alex moved only .1 degrees in the last hour, he did indeed slow down


If he can keep that up he might make it to the 9PM advisory after all.
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2282. Patrap
NEXRAD Radar Brownsville, Base Reflectivity 0.50 Degree Elevation Range 248 NMI 40 Frame Loop


Member Since: July 3, 2005 Posts: 428 Comments: 129902
2280. Drakoen
Very impressive to get this strong and well developed of a storm in June.
Member Since: October 28, 2006 Posts: 57 Comments: 30832
2279. xcool
he slowed down alot
Member Since: September 26, 2009 Posts: 2 Comments: 15684
alex moved only .1 degrees in the last hour, he did indeed slow down
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Good thing its running out of room...WOW!

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2276. Patrap
NEXRAD Radar
Brownsville, Base Reflectivity 0.50 Degree Elevation Range 248 NMI


40 Frame Loop

Member Since: July 3, 2005 Posts: 428 Comments: 129902
2275. IKE
Quoting Patrap:
Well the WEST @ 12 is stale.



Looks like it's slowed down....again.
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Beach cam SPI

http://www.southpadrelive.com/mid-beach.htm
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2273. Grothar
Look at the temperatures it is still over.

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Quoting Tazmanian:
950mbs?


Recent dropsonde in the eye.
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Quoting Tazmanian:
950mbs?

thats close to cat 4 pressure
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2270. Patrap



Member Since: July 3, 2005 Posts: 428 Comments: 129902
This is the last advisory before it goes inland.
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Quoting Stormchaser2007:
Up to 100mph!

Only 4mbs to go until it beats Audrey!
Let's see...
Member Since: September 2, 2009 Posts: 130 Comments: 21194
2267. xcool
see cat 2
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Alex dropped 9mbs.
Member Since: June 9, 2007 Posts: 4 Comments: 15950
Cat 2 now....
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Quoting AlexEmmett:

wow check ur facts before u post
well, the fact is that everybody thought that if Alex sat over water for a long time that he would be a cat. 3, also the pressure drop says different than the winds. while i have been reading for the past 24 hrs. that this should be a cat.2 with the pressure it has. plain and simple that Alex is not as strong as everyone thought it could be given the conditions. my statement was based on what i have read on this blog. as my comment stands it was opinion. i didn't say anything was a fact. i also asked a question. can you talk about why it didn't get stronger than it is right now? thanks in advance:)
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2263. Patrap
College of DuPage Meteorology
Severe Weather and Flash Flood Warnings
Member Since: July 3, 2005 Posts: 428 Comments: 129902
6:00 PM CDT Wed Jun 30
Location: 24.4°N 97.2°W
Max sustained: 100 mph
Moving: W at 12 mph
Min pressure: 950 mb
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Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
950mb (28.05 inHg) Sea Level (Surface) 27.2C (81.0F) 27.1C (80.8F) 45 (from the NE) 14 knots (16 mph)
1000mb -457m (-1499 ft) Other data not available.
925mb 238m (781 ft) 26.2C (79.2F) 26.2C (79.2F) 55 (from the NE) 11 knots (13 mph)
850mb 985m (3,232 ft) 22.8C (73.0F) 21.8C (71.2F) 30 (from the NNE) 17 knots (20 mph)
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2260. Patrap
Well the WEST @ 12 is stale.

Member Since: July 3, 2005 Posts: 428 Comments: 129902
Quoting atmosweather:


Hey gamma!!! It's good to be back...this season's gonna be a long one.


I think so, it will be a busy summer on these blogs I am afraid...
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2258. Grothar
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Quoting TampaWeatherBuff:


Thanks. So does my friend, Frodo, who goes by the handle ShireWeatherBuff. ;)

Frodo is ShireWeatherBuff? Well, well. All the secrets are coming out, now. lol ;)
Anybody got a handle on how the tornadoes or rather hopefully no tornadoes are doing down there?
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950mbs?
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Quoting IKE:
...ALEX NOW A CATEGORY TWO HURRICANE...WILL MAKE LANDFALL IN NORTHEASTERN MEXICO VERY SOON...
6:00 PM CDT Wed Jun 30
Location: 24.4°N 97.2°W
Max sustained: 100 mph
Moving: W at 12 mph
Min pressure: 950 mb

awww man 15 mph away from a major
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its out
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2253. leo305
last advisory:

90MPH 959MB

new one:

100MPH 950MB

ah
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Quoting MiamiHurricanes09:
This is the most impressive June storm I have ever seen in my life. It is just stunning to stare at. Now with that being said, God bless those people in Mexico, one hell of a hurricane is heading thier way.





Thanks man! Really appreciate it.

Image of Monterrey before heavy rain:



Image of Monterrey during heavy rain:

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2251. JamesSA
Quoting rainraingoaway:
Man, (just like everybody else in here)it looks to me that Alex is stronger than just a Cat 1....

Can somebody send me a link or tell me where to go to see OZ?

Thanks!

Does Taco Bell have a webcam?
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6PM is out. 100 mph and 950 mb!
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Quoting Patrap:


I know ,,its for a comparative as requested


oh ok lol
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Quoting Levi32:


Pinhole eye is a very special term reserved for eyewalls 5nm across or less. An eyewall of 10 miles across is pretty common for intense Atlantic hurricanes. Don't overuse the term.
Evening Levi, I have been saying the same thing for 2 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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