Alex continues to slowly organize

By: Dr. Jeff Masters , 7:17 PM GMT on June 28, 2010

Share this Blog
2
+

Tropical Storm Alex continues to slowly grow more organized as it steams away from Mexico's Yucatan Peninsula. Satellite loops show that Alex's heavy thunderstorms continue to increase in areal extent, and low level spirals bands are slowly building to the south and north. The clockwise flow around an upper-level high pressure system a few hundred miles west of Alex is bringing about 15 knots of wind shear to the storm, which is slowing intensification. Heavy thunderstorm activity is limited on the storm's northwest side, thanks to the shear and some dry continental air flowing off the coast of North America. Sea Surface Temperatures are very warm, 29°C. The latest Hurricane Hunter center fix, at 12:07 pm CDT, showed a central pressures of 990 mb, a 1 mb rise in six hours. Top winds were holding steady near 60 mph. Alex has stalled out the last few hours, as it began to "feel" the trough of low pressure to its north breaking down the high pressure ridge that has been pushing the storm to the west-northwest. This stall has allowed the storm to churn up cold water from the depths, which is probably interfering with development. Satellite loops show that Alex has a very large circulation covering about 2/3 of the Gulf of Mexico. We can expect that should Alex become a Category 2 or stronger hurricane, its storm surge will affect a much wider stretch of coast than Hurricane Dolly of 2008 did.


Figure 1. Afternoon satellite image of Alex.

Track forecast for Alex
The latest 12 UTC (7am CDT) runs of our most reliable computer models have come into much better agreement. A consensus forecast arrived at by averaging together most or all of the tracks of our top models--the GFS, ECMWF, GFDL, NOGAPS, HWRF, UKMET, and GFDN--is pretty much what NHC always uses as the basis of their forecast. This consensus forecast has narrowed in on the region just south of the Texas/Mexico border as being the most likely landfall location, with the usual cone of uncertainty surrounding it. The computer model that had been making the northernmost landfall predictions, the Canadian model, is now projecting a landfall 100 miles south of the Texas/Mexico border. There has been a general southward shift of the models in their latest runs, and the most northerly landfall location, near Port Mansfield, is now being predicted by the HWRF model. The earliest landfall time is Wednesday morning, and the latest is Thursday morning. Which model should you trust? Last year, the best performing models at the 3 day forecast period were the GFS, Canadian, ECMWF, and GFDL.

With steering currents relatively weak, the uncertainty in landfall location is high. The average error in an NHC 72-hour track forecast last year was 230 miles, which is about the distance from Brownsville to Port O'Connor. Consider also that the NHC cone of uncertainty is the region where 2/3 of the time (using the last 5 years of statistics) the center of a storm will go. Forecast errors tend to be equally large along track (speed errors) and cross-track (deviations from side-to-side), so that means that about 20% of the time a storm will not be in the cone of uncertainty. Given the slow motion of Alex and the recent uncertainty of the computer models, people living just beyond the edge of the cone of uncertainty should not be confident yet that Alex will miss them.

To get the probability of receiving tropical storm force winds or hurricane force winds for your location, I recommend the NHC wind probability forecasts. The 10am CDT (15 UTC) wind probability product predicted that Brownsville, Texas had the highest odds of getting a direct hit from Alex:

Brownsville, TX: 67% chance of tropical storm conditions (winds 39+ mph), 16% chance of hurricane force winds (74+ mph). This is the cumulative probability through Saturday morning. The wind probability forecasts also include separate probabilities for each 12-hour period between now and three days from now, and each 24 hours for the period 4 - 5 days from now.

La Pesco, MX: 49% tropical storm, 6% hurricane.

Tampico, MX: 31% tropical storm, 4% hurricane.

Corpus Christi, TX: 45% tropical storm, 6% hurricane.

Freeport, TX: 23% tropical storm, 2% hurricane.

Galveston, TX: 21% tropical storm, 1% hurricane.


Figure 2. Skill of computer model forecasts of Atlantic named storms during 2009. OFCL=Official NHC forecast; GFS=Global Forecast System model; GFDL=Geophysical Fluid Dynamic Laboratory model; HWRF=Hurricane Weather Research Forecasting model; NOGAPS=Navy Operational Global Prediction System model; UKMET+United Kingdom Met Office model; ECMWF=European Center for Medium Range Weather Forecasting model; CMC=Canadian GEM model; TVCN=one of the consensus models that lends together all (or most) of the above models; BAMM=Beta and Advection Model (Medium Layer.) Image credit: National Hurricane Center 2009 verification report.

Uncertainty in the NHC Cone of Uncertainty
A research project funded by NOAA known as the Joint Hurricane Testbed has produced a remarkable number of tools now in operational use at the National Hurricane Center to improve hurricane forecasts and warnings. One of these projects, called "Prediction of Consensus TC Track Forecast Error and Correctors to Improve Consensus TC Track Forecasts", was an effort by Dr. Jim Goerss at the Navy Research Lab to improve the accuracy of the NHC "cone of uncertainty" (AKA the "Cone of Death") showing where a storm is expected to track 2/3 of the time. The radius of the circles that make up the cone are based on error statistics of the official NHC forecast over the past five years. We can expect in certain situations, such as when the models are in substantial disagreement, a consensus forecast made using these models will have much greater than average errors. Since the NHC typically bases their forecast on a consensus forecast made using a combination of reliable hurricane forecasting models, it is instructive to view the "GPCE" (Goerss Prediction Consensus Error) circles to see if the uncertainty cone should be smaller or larger than usual. The consensus forecast I'll look at is called "TVCN", and is constructed by averaging the track forecasts made by most of (or all) of these models: GFS, ECMWF, NOGAPS, GFDL, HWRF, GFDN, and UKMET. In the case of this morning's 12 UTC (7am CDT) June 28 run of these models, here is what the radius of the "cone of uncertainty" should be, in nautical miles:

12 hours: 42 nm
24 hours: 73 nm
36 hours: 96 nm
48 hours: 112 nm
72 hours: 173 nm
96 hours: 327 nm
120 hours: 376 nm

And here is the radius of NHC's "cone of uncertainty" for their official forecast, based on the average errors for the past five years:

12 hours: 36 nm
24 hours: 62 nm
36 hours: 85 nm
48 hours: 108 nm
72 hours: 161 nm
96 hours: 220 nm
120 hours: 285 nm

So, the GPCE error estimates are showing that the latest forecasts for Alex out to 72 hours are 4% - 17% higher in uncertainty than average. The 4 - 5 day forecasts are 32% - 49% more uncertain than average--but of course, we expect Alex to be inland at those times.

Intensity forecast for Alex
Alex is currently over a region of ocean with relatively low total ocean heat content (about 10 - 30 kJ/cm^2). By Tuesday and Wednesday, the heat content will increase to 40 - 70 kJ/cm^2, which is high enough to allow Alex to rapidly intensify. Wind shear is currently a moderate 15 knots, and is projected by the SHIPS model to decrease to the low range, below 10 knots, on Tuesday and Wednesday. The combination of low wind shear and high ocean heat content should allow Alex to intensify into a hurricane. NHC is giving Alex a 78% chance of being a hurricane on Wednesday morning, and a 16% chance it will be a major hurricane at that time. Water vapor satellite images, though, show plenty of dry air over Texas and the adjoining waters, and this dry air may turn out to be a significant detriment to Alex. Another factor limiting Alex's intensification may be that the atmosphere is more stable than usual right now--temperatures at 200 mb are a rather warm -50°C, and are expected to warm an additional 1 - 2 degrees by Wednesday. Another factor limiting Alex's intensification may be its slow forward speed. Alex has already stalled out once, and may stall out later in its path, as well. A stalled-out storm tends to pull up cold water from the depths, limiting intensification. In short, Alex has the potential to intensify into a major hurricane, but there are enough roadblocks that I give a 20% chance of this happening.

Elsewhere in the tropics
None of the reliable computers models is calling for tropical storm formation over the the next seven days in the Atlantic.

Wind and ocean current forecast for the BP oil disaster
It currently appears that Alex will not directly affect the oil slick location, other than to bring 2 - 4 foot swells to the region on Wednesday. However, because Alex is such a deep low pressure region, strong southeast winds of 15 - 25 knots will blow over the oil slick region today through Wednesday, according to the latest marine forecast from NOAA. The resulting currents should act to push oil to the west and northwest onto portions of the Louisiana, Mississippi, and Alabama coasts, according to the latest trajectory forecasts from NOAA and the State of Louisiana. Oil will also move westward along the central Louisiana coast towards the Texas border.

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

Portlight continues its Haiti response
Hurricane season is here, and Haiti is not ready. Over 1.5 million Haitians are living outside in tents or under tarps, and are highly vulnerable to a hurricane. Portlight is working on constructing steel shelters out of shipping containers for homeless Haitians, as detailed in the Haitian Relief Recap blog post. Please visit the Portlight.org web site or the Portlight blog to learn more and to donate to Portlight's efforts in Haiti.


Figure 3. Still frame from the remarkable video taken inside the Haitian Presidential Palace during the 2010 earthquake.

To remind people of just how devastating the earthquake was, the Haitian government released a video earlier this month showing the inside of the Haitian Presidential Palace during the mighty Haitian earthquake.

Next post
Dr. Rob Carver is planning on making a post late tonight, and I'll have an update by 9:30am CDT on Tuesday.

Jeff Masters

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1257 - 1207

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65Blog Index

1257. JLPR2
1181. Snowlover123 7:26 PM AST on June 28, 2010

Did you cry with Toy Story? LOL
Member Since: Posts: Comments:
Quoting theWoodman:
Located in Bridge City Texas. Took the eye of Rita and 2 feet of water from Ike. I don't believe this storm will come any farther north than Corpus Christi. But I am dusting off the left over MRE's and looking for water jugs just in case.


Lol. I'm in Vidor. At least MRES after Ike will keep longer than the paper box with peanut butter, crackers and apple juice after Rita. I don't think those were official MRES. lol
Member Since: Posts: Comments:
1255. Patrap
.."Sing loud for the sunshine, pray hard for the rain,

And show your love for Lady Nature.

And she will come back again"..



Member Since: July 3, 2005 Posts: 421 Comments: 127702
1224. pipelines

That is what this blog does, at least for the last 5 years I have been viewing it. Some of it informed speculation, some of it WAG. Not going to change.
Member Since: Posts: Comments:
pipeline..you just have to know who to listen to and who to ignore. Also, you just have to get to understand the different "personalities" on the blog. Some are jokesters...some talk back and forth to each other making wise cracks, etc..we even have this dude that was banned like five times who now has two handles that answers his own questions...its a trip on here..stick to Levi, StormW, Pat, Drak, and some others and you will be fine. Enjoy!
Member Since: August 16, 2007 Posts: 1 Comments: 2337
1252. Levi32
Gotta run....back later.
Member Since: Posts: Comments:
1251. Levi32
Quoting stormwatcherCI:



Can someone please explain to me what the long arrow that extends from the Caribbean sea up to Alex signifies.


Pointing from the half-cutoff advisory box at the bottom of the image....the arrow points from the box to Alex...it's just unusually far away from it on the map.
Member Since: Posts: Comments:
Quoting tennisgirl08:
Is it rare for us to even be talking about a Cat-2 or Cat-3 hurricane in JUNE?
Yes
Member Since: Posts: Comments:
Ha! That's a scary thought. I actually really like to cook, so I make him stay out of my kitchen. ;-)
Member Since: Posts: Comments:
Quoting smmcdavid:
For you Storm, I'd make dinner any day.

Actually... I make dinner every day. Have to make hubby take me out once or twice a month.


I'm about 5 minutes from Katy and my wife hates to cook. What time do you normally have dinner ready? LOL.
Member Since: Posts: Comments:
Quoting Levi32:


Most definitely....another reason why this season is scary. The very fact that Alex is going to be coming in from the west, possibly deepening at landfall without a trough recurving it and shearing it, is phenomenal in June. This is not your typical season opener.


Yeah, that's what I thought! Not good.
Member Since: July 17, 2008 Posts: 0 Comments: 1242
Quoting smmcdavid:
Me too txalways... but I live in Katy now, so I don't have to worry as much as I used to! Right now I'm more concerned about the Rockport area. My parents have a canal house in Key Allegro.


Ohh I didn't know you moved :( I went to high School out there
Member Since: Posts: Comments:
how about everybody on here get off and go to bed and wake up in the morning and start over again then we should have a clearer picture well better than that how about everyone take a break go to walmart and start buying supplies just in case the tracks change and alex is coming your way
Member Since: Posts: Comments:



Can someone please explain to me what the long arrow that extends from the Caribbean sea up to Alex signifies.
Member Since: October 9, 2008 Posts: 0 Comments: 8288
1241. Levi32
Quoting tennisgirl08:
Is it rare for us to even be talking about a Cat-2 or Cat-3 hurricane in JUNE?


Most definitely....another reason why this season is scary. The very fact that Alex is going to be coming in from the west, possibly deepening at landfall without a trough recurving it and shearing it, is phenomenal in June. This is not your typical season opener.
Member Since: Posts: Comments:
1240. BDAwx
I would just like to point out that it does not take a major hurricane, or even a hurricane for that matter, to wipe your home off the map - a tropical storm can do just that.
Member Since: Posts: Comments:
Quoting stillwaiting:
Alex blog,w/forecast path,all "north tx/la"casters are welcome to join in the debate!!!(I think my cone might raise a few eyebrows!!!)
Yeah. It probably ain't gonna happen.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
1237. Patrap
Member Since: July 3, 2005 Posts: 421 Comments: 127702
Quoting FormerTigergirl:


You want to tell that to all those poor people who's homes were wiped off the map...


Heck, I remember people on this blog, even while Ike was landfalling, talking about how lame and how much of a letdown it was.

Dawn told a different story.
Member Since: Posts: Comments:
1235. Torgen
Quoting StormW:


LMAO!

I really don't mind the questions though.

I thought you were makin' dinner though? LOL!


If we're done with the political sniping, I'll come back and put some 15 Bean Cajun Soup with some ham hocks in the crock pot, and start soaking the collards. :)

So, Alex still hasn't gotten "off the pot" yet? Did someone give him a giant green park bench from St. Petersburg to sit on? At least we're getting some rain here in Tampa from it.
Member Since: Posts: Comments:
Quoting StormW:


LMAO!

I really don't mind the questions though.

I thought you were makin' dinner though? LOL!
Storm, I mean Spike :)
Member Since: Posts: Comments:
Quoting StormW:
Ok gang, let's take a breath, and chill...the weakness right now means, that Alex will have a tendency to move in a basic N-NNW direction for about the next 6-12 hours...SLOWLY...Let's not make any SOLID TRACK CALLS until we get the G4 data, and see how the steering layers look in the early morning. There are still MANY variables that have to and will come into play.

AS always a voice of reason, agreed 100% StormW
Member Since: April 29, 2007 Posts: 0 Comments: 7725
Why are there so many people on here claiming the NHC, NWS, Dr.Masters, the billions of dollars worth of model runs, are all wrong? Where are your degrees in atmospheric science? Who are you to say the professionals are wrong? This blog is getting hard to read due to the many idiotic posts claiming NOLA landfall, cat 5 status, Florida landfall, random eye formation, bloody center relocation (please get a grip, center locations simply don't happen in well formed storms), rapid intensification (there isn't even a CDO to speak of right now!). If you have no idea what you're talking about (and if you have made any of the stated claims today, you have no idea what you're talking about) please refrain from posting sensationalist, ignorant claims. They bury the actual educated posts with garbage. Some of us want better insight into what may ACTUALLY happen.

Thank you.


um..because it happens every year....
Member Since: Posts: Comments:
Quoting pipelines:
Why are there so many people on here claiming the NHC, NWS, Dr.Masters, the billions of dollars worth of model runs, are all wrong? Where are your degrees in atmospheric science? Who are you to say the professionals are wrong? This blog is getting hard to read due to the many idiotic posts claiming NOLA landfall, cat 5 status, Florida landfall, random eye formation, bloody center relocation (please get a grip, center locations simply don't happen in well formed storms), rapid intensification (there isn't even a CDO to speak of right now!). If you have no idea what you're talking about (and if you have made any of the stated claims today, you have no idea what you're talking about) please refrain from posting sensationalist, ignorant claims. They bury the actual educated posts with garbage. Some of us want better insight into what may ACTUALLY happen.

Thank you.


"Like"
Member Since: Posts: Comments:
Quoting CybrTeddy:
I'd like to see this NE movement persist for a few more hours before I call it a trend. Most likely a wobble imo.
Likely it is more of an allusion than actual "wobbling" LOL.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
For you Storm, I'd make dinner any day.

Actually... I make dinner every day. Have to make hubby take me out once or twice a month.
Member Since: Posts: Comments:
Is it rare for us to even be talking about a Cat-2 or Cat-3 hurricane in JUNE?
Member Since: July 17, 2008 Posts: 0 Comments: 1242
Alex blog,w/forecast path,all "north tx/la"casters are welcome to join in the debate!!!(I think my cone might raise a few eyebrows!!!)
Member Since: Posts: Comments:
1226. xcool
stormpetrol :)____
Member Since: September 26, 2009 Posts: 2 Comments: 15626
F5 time
Member Since: May 27, 2009 Posts: 0 Comments: 4436
Why are there so many people on here claiming the NHC, NWS, Dr.Masters, the billions of dollars worth of model runs, are all wrong? Where are your degrees in atmospheric science? Who are you to say the professionals are wrong? This blog is getting hard to read due to the many idiotic posts claiming NOLA landfall, cat 5 status, Florida landfall, random eye formation, bloody center relocation (please get a grip, center locations simply don't happen in well formed storms), rapid intensification (there isn't even a CDO to speak of right now!). If you have no idea what you're talking about (and if you have made any of the stated claims today, you have no idea what you're talking about) please refrain from posting sensationalist, ignorant claims. They bury the actual educated posts with garbage. Some of us want better insight into what may ACTUALLY happen.

Thank you.
Member Since: Posts: Comments:
1223. Cranica
Storms with large windfields don't generally explode, but a storm with a large circulation can strengthen rapidly by tightening its energy into a smaller area. Wilma is, once again, a good analogue - not that Alex is likely to blow up like that, but he'll probably gain some strength as soon as that huge band to the northeast contracts into the center.
Member Since: Posts: Comments:
I'd like to see this NE movement persist for a few more hours before I call it a trend. Most likely a wobble imo.
Member Since: July 8, 2005 Posts: 259 Comments: 23654
Quoting IMA:
Know what amazes me, but definitely shouldn't? The number of people in San Antonio who don't even know this is out there & are talking about leaving for the Coast or going to Medina Lake as soon as Wednesday or Thursday to start the holiday weekend early.

*Shakes her head at the uninformed, idiotic people who can almost make her look like a genius*

My mother was right, I should've tried harder to get the rest of my things out of the house I shared with my ex, the house that is in the Hill Country, the house that sits where a creek & river meet, the house that flooded once (before we owned it) due to a tropical system. Thank goodness Mom doesn't read this blog, I'd hate for her to see that I said she was right!


Hi, Ima. Didn't you tell me last year that you are out in Pipe Creek?

Most of the people I've been talking to here in S.A. are aware of the storm and it's impending approach.
Member Since: Posts: Comments:
1219. Patrap
Member Since: July 3, 2005 Posts: 421 Comments: 127702
Located in Bridge City Texas. Took the eye of Rita and 2 feet of water from Ike. I don't believe this storm will come any farther north than Corpus Christi. But I am dusting off the left over MRE's and looking for water jugs just in case.
Member Since: Posts: Comments:
Quoting StormW:


I don't think it will go that far...he will however move very slowly in a northward direction, until that weakness fills.


Ah ok. Thanks. Didn't think I knew what I was talking about. Lol.


Steering currents change with time. The map won't look like that tomorrow or the next day. They currently would take Alex north but that ridge over the Rockies is coming east and will turn Alex back towards the WNW eventually, so no it's not going to NOLA.

Thanks Levi. :)
Member Since: Posts: Comments:
1216. xcool
Alex get strong....
Member Since: September 26, 2009 Posts: 2 Comments: 15626
Quoting xcool:
stormpetrol how about bud light
or MGD64
Member Since: Posts: Comments:
Me too txalways... but I live in Katy now, so I don't have to worry as much as I used to! Right now I'm more concerned about the Rockport area. My parents have a canal house in Key Allegro.
Member Since: Posts: Comments:
Blog topic just turned to a beer conversation, only at WU. LOL!
Member Since: September 2, 2009 Posts: 130 Comments: 21091
1212. jsit
is this thing going through an eyewall replacement cycle?
Member Since: Posts: Comments:
1208. help4u
Gfdl 108 mile hurricane right on the texas ,mexico border.
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
Well it's just that Alex is so....big. Big storms don't typically explode in strength.

However Ike was a Cat 2, and we could see something along those lines. But Ike did not make landfall as a major hurricane in Texas. And there is a mindset among some here that a hurricane has to be major to be a real threat. It doesn't. Ike showed that very well.


You want to tell that to all those poor people who's homes were wiped off the map...
Member Since: Posts: Comments:

Viewing: 1257 - 1207

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.