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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2 Hurricane Hunters on task.



AOI

AOI

AOI

Hurricane Hunter Data

TS BUSTED FORECAST ALIBI
Member Since: October 1, 2007 Posts: 81 Comments: 26516
Quoting MiamiHurricanes09:
That would be considered 1mph over a 12 hour period. Best the NHC keep it stationary.

I've watched how the NHC operates for years now, thats how they always do it unless its a significant movement, but I said earlier it was drifting ever so so slightly east of north.
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1404. CCkid00
Quoting pipelines:


Oh yeah, I agree. This is a pretty unique situation and a lot of things could happen with this system. That's what I'm frustrated about, I'm trying to take in the informative stuff but it's hard when there is so much useless garbage to sort through! I've been on the blog since 2008 btw, I just rarelly post.

Dr. Masters predicted the NOLA Katrina landfall, while the NHC kept saying it was going to hit the Fla. panhandle. it got past that point, then they said it would turn north and hit Mobile.....they didn't pinpoint it until it actually turned to hit NOLA.
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Time: 23:40:00Z
Coordinates: 21.3833N 91.9W
Acft. Static Air Press: 641.7 mb (~ 18.95 inHg)
Acft. Geopotential Hgt: 3,782 meters (~ 12,408 feet)
Extrap. Sfc. Press: 993.7 mb (~ 29.34 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 72 at 27 knots (From the ENE at ~ 31.0 mph)
Air Temp: 8.5C (~ 47.3F)
Dew Pt: 6.2C (~ 43.2F)
Peak (10s) Flt. Lvl. Wind: 27 knots (~ 31.0 mph)
SFMR Peak (10s) Sfc. Wind: 19 knots (~ 21.8 mph)
SFMR Rain Rate: 3 mm/hr (~ 0.12 in/hr)


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1402. centex
Quoting IKE:
It moved ENE 12 miles.
That would classify as a jog. Especially considering slow movement.
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Quoting skepticall2:


Hahaha I was like what is he talking about till the date. Don't hate appreciate! I'm hoping it is a great game I can't wait.
Believe me. It will. Too bad your going to get whopped. Lol. J/k.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1400. IMA
Quoting katadman:
No, Ima, just ordinary folks. Did you notice it's raining at the moment? Started about fifteen minutes ago.



I've been watching the radar all afternoon & saved these frames. I came out just moments before the air started to cool. It's pouring & I'm loving it - for now!
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Alex like play with you
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Quoting Baltimorebirds:
It should be bringing up colder waters from the depths.It's also in an area that lacks tchp.


To Alex's benefit, TS-strength winds don't stir up water very quickly.
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Quoting nrtiwlnvragn:
Ike,

Did you see the storm the parallel GFS takes into North Carolina? Same one the 12Z GFDL has west of Florida this morning.


I saw that - didn't pay attention enough to see if it's the wave that just exited Africa today. Did you see if it was that one?
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pressure so far on this inbound flight 993.7 mb
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Quoting pipelines:


Oh yeah, I agree. This is a pretty unique situation and a lot of things could happen with this system. That's what I'm frustrated about, I'm trying to take in the informative stuff but it's hard when there is so much useless garbage to sort through! I've been on the blog since 2008 btw, I just rarelly post.



true,WU could use a BS filter setting sometimes!!!!
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Recon now heading back towards Alex's COC.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1391. Patrap
Seems a 357 Heading @ 6mph noted last Hour from my NASA Viewer Marks..

Member Since: July 3, 2005 Posts: 428 Comments: 129767
1390. Roark
@ 1371/Ike: Ditto!! :)
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Quoting skepticall2:


It is wobbling.


Naw brah - the only wobblin' gone be y'all when Jacory's air attack beats dat azz 9/11!!!
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Quoting IKE:
Memo to Alex: Please go somewhere and get this over with. I've walked more today then you've moved.
lmao!
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Ike,

Did you see the storm the parallel GFS takes into North Carolina? Same one the 12Z GFDL has west of Florida this morning.
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Quoting IKE:
It moved ENE 12 miles.


hmmmm
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Quoting reedzone:


LOL so true, Alex is now ENE of the models.. 00z data will be very important since it should have the G4 data.
12 miles is insignificant.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting IKE:
It moved ENE 12 miles.
That would be considered 1mph over a 12 hour period. Best the NHC keep it stationary.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting IKE:
Memo to Alex: Please go somewhere and get this over with. I've walked more today then you've moved.


LOL so true, Alex is now ENE of the models.. 00z data will be very important since it should have the G4 data.
Member Since: July 1, 2008 Posts: 13 Comments: 7437
1379. TXHolly
Quoting homelesswanderer:


Lol. I'm in Vidor. lol


I'm a longtime lurker who also lives in Vidor. Good to know I'm not the only one here that keeps up with this blog.
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1378. NRAamy
Hurricanes can do funky things ;)

especially to outhouses with My Little Pony Shower curtains....
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1376. Michfan
For those of you following the missions on google earth. Mission 6 is the G4. You can see all the dropsondes they are dropping all over the GOM. Mission 7 and the nontasked one are hurricane hunters.
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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.
This is a good statement ,however when the Hurricane Center is off 220-miles on their 72-hr forecasts .This leaves roon for debate.I enjoy it....
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1373. leo305
Quoting leo305:
may even be moving ENE..


looks like it was moving ENE
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The last June Cat 2 and higher was hurricane Alma in 1966 with winds of up to 125 mph.
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1371. IKE
Memo to Alex: Please go somewhere and get this over with. I've walked more today then you've moved.
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Alex stationary, not surprising. Thoughts on what this may do to the track?
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just got this tweet from Jim Cantore -The 00Z model run will contain data from NOAA's Gulfstream Aircraft. This crucial data set will help in determining Alex's eventual path.
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1368. Patrap
Floater - RGB Color Infrared Loop
Member Since: July 3, 2005 Posts: 428 Comments: 129767
1367. JLPR2
Quoting washingaway:
There are two missions currently on Google earth, Mission 6 & 7


I got three with a non tasked one, what's up with that?
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Quoting stillwaiting:




2 days ago alot of mets and the NHC,said the 2 out lying north models had feedback,and that appears not to be the case,I think the CMC is doing pretty darn well,alot of the time the knowledgable people on this blog point out things that might happen,before the offical forecasts do!!!


Oh yeah, I agree. This is a pretty unique situation and a lot of things could happen with this system. That's what I'm frustrated about, I'm trying to take in the informative stuff but it's hard when there is so much useless garbage to sort through! I've been on the blog since 2008 btw, I just rarelly post.
Member Since: July 10, 2008 Posts: 0 Comments: 227
That stalled movement certainly wont help Alex intensify. Its been over the same waters for 24 hours.
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1364. Michfan
The nontasked flight is heading straight into the center from the north. Descent is taking place now.

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1363. xcool
me to
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I was right, the center is NE of where it was earlier, my eyes weren't tricking me :)
Member Since: July 1, 2008 Posts: 13 Comments: 7437
1361. IKE
It moved ENE 12 miles.
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Quoting RitaEvac:
I'm gonna keep showing this till its drives everybody nuts






and i hop you dont get a banned for it
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Quoting btwntx08:

that hwrf mskes two loops lol i just dont see it doing a loop twice


Hurricanes can do funky things ;)





Things get even weirder in the Pacific.


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I think they are setting up so that one plane is going through the center while the other plane is on the edge of the storm so that it prevents collisions during strong updrafts or downdrafts
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Quoting Hurricanes101:


G4 is the plane they use to help determin the steering currents ahead of the storm


OOOOH. That's what it is. Thanks was wondering. :)
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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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