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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BRO: Port Isabel [Cameron Co, TX] amateur radio reports HURRICANE at 04:30 PM CDT -- ham radio operators report that one foot of sea water was over the bulkheads near tarpon street and downed power lines were in the water smoking.
Member Since: Posts: Comments:
Quoting Levi32:
You don't get Cat 1 hurricanes with 955mb pressure....it simply does not happen. I can accept this being a solid Category 2, but it has the pressure and appearance of a major hurricane.


Wasn't Ike a 944 mb cat. 2?

Quoting Stormchaser2007:


Eyewall coming ashore!

Quoting neonlazer:
223300 2420N 09709W 8431 01069 9516 226 209 048011 018 029 003 00

951.6!!!!!!!


Where are you getting this?
Member Since: August 30, 2008 Posts: 8 Comments: 2834
2196. JamesSA
It is too bad there is not a webcam in San Fernando Tamaulipas.
Member Since: August 17, 2009 Posts: 0 Comments: 579
Oh my goodness Rich/Atmos is back too!!!
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Quoting sarahjola:
Alex is big, but not so powerful. i personally thought we would see a monster burst out of Alex. he sat over hot water for a long time and he kept us on our toes for a long time. he just couldn't get it together. it is a nice looking hurricane, and I'm not saying Alex is not worth worrying about. Alex is huge and i am sure its not safe to be anywhere near the eye. i know the storms he spits out will be dangerous, but he's just not the monster i thought he would be after the amount of time he has been in perfect conditions for intensification. why is it that Alex didn't gain the strength we all thought he could? thanks in advance:)
i am glad Alex is not too bad. good for everyone:)

wow check ur facts before u post
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Member Since: June 9, 2007 Posts: 4 Comments: 15718
2192. Grothar
Quoting barbamz:

In Germany it's already tomorrow. Happy birthday, Grothar!


Ich danke Ihnen,sehr! So tell us, if it already tomorrow there, how strong did Alex get before hitting Mexico?
Member Since: Posts: Comments:
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.



Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting Levi32:


Rich! All the old gang is coming back :)


Great to see ya Levi! It wouldn't be summer without being here =)
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All I can say is WOW! Beautiful storm....Be careful to everyone in its path!!

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this is a very very bad omen for the season
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Alex is big, but not so powerful. i personally thought we would see a monster burst out of Alex. he sat over hot water for a long time and he kept us on our toes for a long time. he just couldn't get it together. it is a nice looking hurricane, and I'm not saying Alex is not worth worrying about. Alex is huge and i am sure its not safe to be anywhere near the eye. i know the storms he spits out will be dangerous, but he's just not the monster i thought he would be after the amount of time he has been in perfect conditions for intensification. why is it that Alex didn't gain the strength we all thought he could? thanks in advance:)
i am glad Alex is not too bad. good for everyone:)
Member Since: Posts: Comments:
2186. Patrap
Classic Look here..one fo da books

NEXRAD Radar
Brownsville, Velocity Azimuth Display Wind Profile Range 124 NMI

Member Since: July 3, 2005 Posts: 415 Comments: 125628
Quoting neonlazer:
Yall think HH's will have time to make another pass?

after this theyll make time
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this is not your evere day june storm
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Quoting TampaWeatherBuff:


But for the Yucatan, Alex would have been a monster. But for the steering, and he would have been an epic disaster. As it was, he was this season's "warm up," a kind of practice run. Batten down the hatches! ;)

Yes, he has been a big "but" of a storm this entire time. Like your avatar, by the way. ;)
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2182. Patrap
NEXRAD Radar
Brownsville, Storm Relative Mean Radial Velocity 2.40 Degree Elevation Range 124 NMI

Member Since: July 3, 2005 Posts: 415 Comments: 125628
Quoting clwstmchasr:


Your birthday and my anniversary. That reminds me, I need to get out and get something for the wife.


Don't forget, it's Canada's birthday too! But some goods are taking an 8% tax hike (HST) in my province tomorrow GRR.
Member Since: August 30, 2008 Posts: 8 Comments: 2834
Yall think HH's will have time to make another pass?
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2179. JamesSA
Quoting Levi32:
Look at the outflow....you almost can't get more perfect than that....the streamlines going perpendicular OUT from the eye in every direction. Center of ZERO shear is over the eye. That is as symmetrical of an upper high as you could want.


It is an amazing change from the ragged thing we have been watching for days now.
Member Since: August 17, 2009 Posts: 0 Comments: 579
2178. hydrus
Quoting StormChaser81:
This puts it into perspective...

Do you have a link for that S.C.81?
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2177. Levi32
Quoting atmosweather:
Down to 952mb...

223300 2420N 09709W 8431 01069 9516 +226 +209 048011 018 029 003 00


Rich! All the old gang is coming back :)
Member Since: November 24, 2005 Posts: 628 Comments: 26455
I know they're not at the surface, but the radar velocities are increasing.

Member Since: August 2, 2006 Posts: 45 Comments: 11556
i see a upgrade too cat 3 comeing
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Alex even stronger, it might beat Audrey's record. Pressure is 951.6mb.

000
URNT15 KNHC 302238
AF304 1201A ALEX HDOB 48 20100630
222830 2412N 09655W 8430 01260 9729 +200 +200 217066 068 065 006 00
222900 2414N 09656W 8429 01238 9716 +179 +179 216075 079 071 021 05
222930 2415N 09658W 8432 01199 9990 +176 +999 208070 072 076 015 05
223000 2416N 09659W 8433 01167 9629 +200 +195 202073 077 077 010 03
223030 2417N 09700W 8437 01151 9602 +207 +192 200054 058 050 007 03
223100 2418N 09702W 8437 01113 9574 +215 +192 199040 044 048 007 00
223130 2419N 09704W 8429 01104 9555 +215 +195 201031 035 042 004 00
223200 2419N 09705W 8434 01085 9540 +217 +199 206018 020 035 005 03
223230 2420N 09707W 8424 01086 9528 +220 +204 184010 014 032 002 03
223300 2420N 09709W 8431 01069 9516 +226 +209 048011 018 029 003 00
223330 2421N 09711W 8429 01079 9529 +213 +213 025032 042 038 005 00
223400 2421N 09712W 8438 01097 9557 +214 +214 024047 049 999 999 03
223430 2422N 09712W 8415 01128 9560 +211 +211 039050 051 052 005 03
223500 2423N 09711W 8425 01111 9557 +214 +214 052049 049 053 006 00
223530 2424N 09710W 8433 01105 9561 +209 +209 065045 046 052 006 03
223600 2425N 09709W 8425 01117 9568 +207 +207 081048 052 052 006 00
223630 2426N 09709W 8432 01124 9580 +207 +207 092063 070 061 006 00
223700 2427N 09708W 8440 01139 9602 +202 +202 095080 082 065 009 03
223730 2427N 09707W 8433 01136 9990 +187 +999 096089 094 068 010 05
223800 2428N 09706W 8434 01147 9990 +186 +999 100097 098 074 010 01
$$
;

Member Since: September 2, 2009 Posts: 130 Comments: 21032
2172. Levi32
Quoting AstroHurricane001:


Hey, what did I tell you six months ago? The global oceans have warmed quickly...most of the extra heat is concentrated over the Atlantic.


We were all talking about it 6 months ago.
Member Since: November 24, 2005 Posts: 628 Comments: 26455
Flight level
From 100° at 97 knots
(From the E at ~ 111.5 mph)
Member Since: June 9, 2007 Posts: 4 Comments: 15718
Quoting c150flyer:
I'm not a station, just a guy with an anemometer looking like an idiot on the side of the freeway, but i can confirm what you just said... nowhere near TS strength sustained here............yet?? =)

BTW - Thanks patrap for the quick info. I'm getting some good sustained winds in the neighborhood of 25mph, the gusts are just being kind of puny.

Good for Brownsville. Bad for my adrenaline lol.

You guys be safe out there. Glad the winds aren't too bad. :)
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Quoting HurricaneSwirl:


WOW.

DAMN MAN if thsi isnt a cat 3 i dont what is
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Perfect June storm 3D

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2166. Levi32
951.6mb extrapolated it's deepening very quickly.
Member Since: November 24, 2005 Posts: 628 Comments: 26455
Quoting Levi32:
Look at the outflow....you almost can't get more perfect than that....the streamlines going perpendicular OUT from the eye in every direction. Center of ZERO shear is over the eye. That is as symmetrical of an upper high as you could want.



But for the Yucatan, Alex would have been a monster. But for the steering, and he would have been an epic disaster. As it was, he was this season's "warm up," a kind of practice run. Batten down the hatches! ;)
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2164. hydrus
Quoting Levi32:
Look at the outflow....you almost can't get more perfect than that....the streamlines going perpendicular OUT from the eye in every direction. Center of ZERO shear is over the eye. That is as symmetrical of an upper high as you could want.

It is intensifying rapidly. A testament to its almost perfect outflow.
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Wow, it looks like most of the usual suspects are here for the landfall of Alex! Boy he sure got his act together today, can't wait to see what the final numbers are for him. Hope they got the word and have taken cover in the landfall area, it could be ugly around the bay Alex is headed for!
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2162. xcool
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Down to 952!

6mbs left.
Member Since: June 9, 2007 Posts: 4 Comments: 15718
Quoting neonlazer:
223300 2420N 09709W 8431 01069 9516 226 209 048011 018 029 003 00

951.6!!!!!!!


WOW.
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Alex is just getting to the point where he could rapid intensify, the eyewall is thickening up nicely. He's got good outflow on all quad's. Land is coming quickly and the water is getting shallower by the hour and land is getting closer.

But still a impressive storm anyway you look at it.
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Quoting Levi32:


That's not a June storm.


Hey, what did I tell you six months ago? The global oceans have warmed quickly...most of the extra heat is concentrated over the Atlantic.
Member Since: August 30, 2008 Posts: 8 Comments: 2834
2157. Levi32
Mexico is very lucky that Alex's large circulation entrained some dry air. The dry air is still evident in satellite and radar limiting the core development, but if he had time to mix it out or if the dry air had never gotten in there at all, he could be challenging Audrey even with a landfall this far south. Explosive deepening would have been very possible.
Member Since: November 24, 2005 Posts: 628 Comments: 26455
2156. Patrap
Member Since: July 3, 2005 Posts: 415 Comments: 125628
this is the best looking TD i evere thing in my life
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thank god it didn't come further north in the gulf...this would have been a nightmare...
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Down to 952mb...

223300 2420N 09709W 8431 01069 9516 +226 +209 048011 018 029 003 00
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CATEGORY 2? Really? This is so beautiful
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2151. snotly
Did it stall?
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223300 2420N 09709W 8431 01069 9516 226 209 048011 018 029 003 00

951.6!!!!!!!
Member Since: Posts: Comments:
CI# /Pressure/ Vmax
5.3 / 963.9mb/ 97.2kt

Member Since: June 9, 2007 Posts: 4 Comments: 15718
Member Since: June 9, 2007 Posts: 4 Comments: 15718

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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.