Alex continues to slowly organize

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

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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

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Quoting drg0dOwnCountry:




See the image from the movie the day after tomorrow. Starting to look that HUGE. Welcome to climate change.


LOL. That image is just ridiculous.
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Quoting CosmicEvents:
Can anyone give me a valid reason not to agree with the current NHC forecast. That Alex is thankfully most likely to be a moderate Cat1 heading into a sparsely populated area. More cows that people. Millions more. Alex is a cow storm.

Nice!
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Quoting taco2me61:
yes Alex had to eat up Darby first then just Explode if you know what I mean....

Taco :o)



Hmmmm.
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2203. FFEMTRQ
Quoting RCThunder:
Can someone educate a rookie? The time stamps on the model runs... what time zone, etc do they mean. The 00Z 6-29 just came out so I assume midnight?



Link
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Quoting RCThunder:
Can someone educate a rookie? The time stamps on the model runs... what time zone, etc do they mean. The 00Z 6-29 just came out so I assume midnight?

CDT is 5 hours before 00 UTC.
EDT is 4 hours ...

CST is 6 hours ...
EST is 5 hours ...

00 UTC, June 29 models begin coincident with 7 pm CDT.
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2200. Chigz
Quoting snotly:



From unisys weather...

Depression TD -----
Tropical Storm TS -----
Hurricane 1 > 980mb
Hurricane 2 965-980mb
Hurricane 3 945-965mb
Hurricane 4 920-945mb
Hurricane 5 < 920mb


No where near CAT 2 pressure! Give it a rest mate!! Lowest pressure found was 985mb
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What are some good add-ons for google earth, that show storm info, paths and guidance model forecasts? The ones I had don't seem to be working anymore. My hurricane hunter one still works though, thanks in advance.
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Quoting MiamiHurricanes09:
Winds still not catching up. Advisory will likely have winds of 65mph and a pressure of 985mb.

that is a heck of a ts though one for the record books for ts's though
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Can anyone give me a valid reason not to agree with the current NHC forecast. That Alex is thankfully most likely to be a moderate Cat1 heading into a sparsely populated area. More cows that people. Millions more. Alex is a cow storm.
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It's gonna do what it's gonna do. While I recognize the diff reasons that someone may not prepare for a hurricane, I have a tough time understanding why someone who loves in a hurricane prone area would not be prepared every day of hurr season.

If you live in LA, do you only pick up supplies once the "big one" strikes?

Again, I get it... but if this is a life or death situation once every five years, that, to me, is worth $50 or $100 in prep supplies... bc if you're not prepared, it's a heckuvalot (yes, i spelled that right) worse.
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noaa jet is flying tonight and sending data. the 06z models should be strong
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Quoting RecordSeason:
#1. Alex is not developing an eye first because it needs a well-established CDO before any of that happens.

#2. Alex is not rapidly intensifying because this is the NHC term of rapidly intensifying:

A decrease in the minimum sea-level pressure of a tropical cyclone of 1.75 mb/hr or 42 mb for 24 hours.

===

Nature cares little about text book distinctions. This storm has a better structure than most category 2 hurricanes. So get over it.

You will see very much intensification before it's all said and done, so just watch.
I rarely go out of my way to insult pple in here, but something about the way you are posting is making want to really blow u out of the water. Be that as it may.....

I'm curious which cat two storms you have seen which looked worse than Alex does now. We'd LOVE to see some imagery if you can find it..... on your other points, you made two non sequiturs in response to the post u quoted. First, you said something about nature not paying attention to textbook definitions, when the poster was actually speaking about OTHER BLOGGERS paying attention to the correct usage of terminology (what's Mother Nature got to do with what he said?). Second, you said something to the effect of "RI soon to come" when the blogger was actually saying no RI happening right now.

I'm getting rather weary of your constantly bombastically bombarding statements about Alex moving NE and hitting Florida based on a brief bobble and your "gut feeling". Give me some meteorological proof, and stop trying to ram your gut feeling down MY throat.

YMMV.
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Quoting PanhandleChuck:
Wow, this is the roughest crowd I've seen all season. Only been on here for three years, but I know when to lay low.


I've found myself lurking quite a bit since Alex formed. People are on edge more when we have an active storm. I tend to get myself in trouble in times like these. :)
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Quoting StSimonsIslandGAGuy:
Well Miamihurricane's avatar smokes a pipe. That makes you look older.

Seriously, miamihurricanes09 is a very knowledgeable blogger, and doesn't post silly stuff here. He's a durn sight better than most of the adults.

And I think adults picking on kids is the lowest of the low.
LOL! Thanks.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
2191. Patrap
Beverly Mitchell-Power of Us #1 by AT&T from evacuteer.org on Vimeo.
Member Since: July 3, 2005 Posts: 421 Comments: 127639
Quoting StSimonsIslandGAGuy:
Well Miamihurricane's avatar smokes a pipe. That makes you look older.

Seriously, miamihurricanes09 is a very knowledgeable blogger, and doesn't post silly stuff here. He's a durn sight better than most of the adults.

And I think adults picking on kids is the lowest of the low.


+1
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As I have said before, I think that the system is going to hit somewhere around 50-100 miles south of the border.

Tommorrow we will have a better clue of what the heck is going on with this system! Is the first storm of the season and it's amazing how the activity in the blog has increased.

Can't imagine how this will get when August-October madness arrives...
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Quoting PanhandleChuck:
Wow, this is the roughest crowd I've seen all season. Only been on here for three years, but I know when to lay low.


Just keep that right shoulder off the mat, whatever you do.
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2187. angiest
Quoting RCThunder:
Can someone educate a rookie? The time stamps on the model runs... what time zone, etc do they mean. The 00Z 6-29 just came out so I assume midnight?


Times are given in GMT/Zulu time.
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Quoting drg0dOwnCountry:




See the image from the movie the day after tomorrow. Starting to look that HUGE. Welcome to climate change.
yes Alex had to eat up Darby first then just Explode if you know what I mean....

Taco :o)
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Quoting xcool:
69 kt FL, 50 kt SFMR. Pressure 985mb
Winds still not catching up. Advisory will likely have winds of 65mph and a pressure of 985mb.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
StormW...How active do you see july being?
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Quoting MiamiHurricanes09:
Between the area the last vortex message was issued and the area the new minimum central pressure as found Alex moved due north 9.1 miles.

well NHC was wrong i see they see its going west the longer its sits the stronger it gets the north it will go
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2181. xcool
i see eyes hmmm ?
Member Since: September 26, 2009 Posts: 2 Comments: 15626
Its weird hoe disorganized Alex is on IR, but yet it can keep dropping that pressure. This might be my avatar for next year.
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Wow, this is the roughest crowd I've seen all season. Only been on here for three years, but I know when to lay low.
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2178. Patrap

A great project proven and well received and designed.

www.evacuteer.org




New Orleans, LA
evacuteer.org

When it comes to exploring our potential as a community, a mandatory evacuation highlights the power of us. Evacuteer.org mobilizes New Orleanians willing to push their boundaries for the collective good.

Pass it around please.

Or bookmark.
Member Since: July 3, 2005 Posts: 421 Comments: 127639
storm?
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2176. Chigz
Quoting tennisgirl08:


Uhh.that was an accident. And I am calling for a Brownsville hit. And I am sticking with my guns.

Also, please STOP quoting fake numbers, lowets pressure found was 985mb and NOT 980! thanks!
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2173. Max1023
2144- The wind variances are likely caused by spiral banding, this is common in developing storms. As Alex does not have an eyewall yet the maximum winds will occur where the convection strength and the pressure gradient combine to form local wind maxima. In this case there was one to the E of the center in a spiral band, and one to the NE, closer and likely due to a different region of the same band.
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Due north on 2nd pass!
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Between the area the last vortex message was issued and the area the new minimum central pressure as found Alex moved due north 9.1 miles.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Can someone educate a rookie? The time stamps on the model runs... what time zone, etc do they mean. The 00Z 6-29 just came out so I assume midnight?
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Quoting RitaEvac:
north south north south, east west, come on Alex make up your damn mind


With all those changes, I think we should rename Alex to Alexa!!!!!
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Quoting MiamiHurricanes09:
Pressure is 985.3mb not 980.0mb.

but if the 2mb/per hr drop continues this would be below 980 in a matter off hours
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Quoting drg0dOwnCountry:




See the image from the movie the day after tomorrow. Starting to look that HUGE. Welcome to climate change.

WOW. It's true, I saw it in a movie!
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2164. Hhunter
Quoting kmanislander:
Alex starting a new phase



yep the kick you in the #$@ phase i am afraid..
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with the ULL to the East decapitating 94L, and on the flip-side Buzzsaw Alex rolling now, for those fans of Highlander:

"the Quickening begins..."
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2162. snotly
Quoting Thundercloud01221991:


we are getting close to what would be equivalent to a cat 2 hurricane pressure



From unisys weather...

Depression TD -----
Tropical Storm TS -----
Hurricane 1 > 980mb
Hurricane 2 965-980mb
Hurricane 3 945-965mb
Hurricane 4 920-945mb
Hurricane 5 < 920mb
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2161. xcool
69 kt FL, 50 kt SFMR. Pressure 985mb
Member Since: September 26, 2009 Posts: 2 Comments: 15626
Isn't this what Pat kept seeing today, swore he saw another coc forming, here it is Pat! lmao

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Quoting tennisgirl08:
Scary stuff...980mb..in June - and more time left for it to intensify.
Pressure is 985.3mb not 980.0mb.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
2157. GetReal
My latest thoughts on Alex...
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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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