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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PChuck, I used to live in the Midwest and it feels like it does before a Tornado here in Panama City. No breeze at all and 78% humidity. Pressure 29.87 and falling.
Member Since: June 27, 2010 Posts: 0 Comments: 760
For some reason I think models are gonna change to Corpus after the G4 runs, dont know why.
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Quoting Seflhurricane:
this storm is more intresting as time goes by i have a real bad feeling about this this is going to pull a fast one on all of us
I'm beginning to think the same thing.
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Quoting IKE:
That graph can be deceiving. If you look at CIMSS upper level winds product you will notice anticyclonic wind barbs above the COC.


Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Patrap:
There is nothing up ..

Save for the NOAA G-4 and a HH C-130.

Enjoy a Fresca..
This is funny Pat. Some are questioning the pilots?
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Most experts are saying Mexico so right now I will go with that landing. I am in Texas and there is a front near me and it is still 100 degrees?
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Our local met felt like a Corpus Christi landfall was more realistic. The G IV jet from NOAA will figure Alex out. It can fly @ 45,000 ft.
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Quoting PanhandleChuck:


Honey BBQ or Chipotle? LOL



both
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
Quoting Kristina40:
Depends on what part of Florida. I'm on the Panhandle and our pressure is falling fast. The air is dead here.


I live near in Milton and I have to agree, The air is very dead
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Quoting homelesswanderer:


I understand it but I live in SE TX. But our NWS is Lake Charles, La. I think Houston was too busy. Lol.

Haha, that is exactly why I used the term generally. It's not a perfect interpretation, but I thought that would be the easiest way to explain it to non-locals.
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Evening Everyone, Back while dinner cooks with a glass of wine. I think I'll be needing it!
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1495. Patrap
There is nothing up ..

Save for the NOAA G-4 and a HH C-130.

Enjoy a Fresca..
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we'll know if its going to mexico by when he hits the 95W longitude
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Quoting kmanislander:


Maybe a mechanical if it did.


Its odd because the original mission turned around as well...

Somethings up.


EDIT. Now the original plane is heading into the center.
Member Since: June 9, 2007 Posts: 4 Comments: 15950
Quoting Tazmanian:
if it gos too Mexico i will eat BBQ crow for the rest of my life


Honey BBQ or Chipotle? LOL
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Depends on what part of Florida. I'm on the Panhandle and our pressure is falling fast. The air is dead here.
Member Since: June 27, 2010 Posts: 0 Comments: 760
this storm is more intresting as time goes by i have a real bad feeling about this this is going to pull a fast one on all of us
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1489. xcool
here come sample the dry air yayy
Member Since: September 26, 2009 Posts: 2 Comments: 15684
if it gos too Mexico i will eat BBQ crow for the rest of my life
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
Quoting Stormchaser2007:
Non tasked mission just turned around...

Whats going on?
Something's up. Try to e-mail the NHC.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Tazmanian:
not heading for Mexico


Wanna bet?
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1484. CCkid00
Quoting usa777:

it was in the cone 2 days in advance, but on the western end of the cone and they were basically still thinking the Fla. panhandle. you can go back on Dr. Master's blog and go to Aug. 2005 and read each post. at one point, he didn't understand why they weren't starting New Orleans evacuations. actually, it's a REALLY interesting read now, after the fact.
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1481. xcool
other plane come in that why..
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting Stormchaser2007:
Non tasked mission just turned around...

Whats going on?


Maybe a mechanical if it did.
Member Since: August 19, 2006 Posts: 0 Comments: 15948
1479. IKE
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What is recon doing? They are nowhere near the COC.
Member Since: May 27, 2009 Posts: 0 Comments: 4438
not heading for Mexico
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
I'm also still leaning toward a MX landfall.
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Quoting bohonkweatherman:
Wonder how much rain the Yucatan is getting with this stalled storm? My wife use to live in Houston and they had a stalled tropical storm drop 30 inches on them years ago.


Allison in '01. Crazy storm
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Mexico
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Non tasked mission just turned around...

Whats going on?
Member Since: June 9, 2007 Posts: 4 Comments: 15950
Quoting DestinJeff:
2100 CIMSS ... watch the High centered over CO weaken

-3:


current:


same thing happens at next steering layer. that high is the one that is supposed to induce the westerly motion of Alex.

Alex needs a latitude adjustment to get steered by that weak-sister of a high pressure, especially if it shifts over to the upper midwest instead of further south.


Events are playing out much like we discussed earlier today. Maybe even a little wobble to the NNE since then which we also touched upon.
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Quoting MiamiHurricanes09:
You're telling me I should take your word over the NHC? I think not.

idk everthing about this strom is strange i recomend not blaming anyone
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Quoting MiamiHurricanes09:
You're telling me I should take your word over the NHC? I think not.



nop nop nop it stall out and its likeing it vary march
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
Quoting DestinJeff:
2100 CIMSS ... watch the High centered over CO weaken

-3:


current:


same thing happens at next steering layer. that high is the one that is supposed to induce the westerly motion of Alex.

Alex needs a latitude adjustment to get steered by that weak-sister of a high pressure, especially if it shifts over to the upper midwest instead of further south.
Definitely NOT good. Let's see if the next graph shows the high weaken.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Jim Cantore said he does not antcipate the storm coming there just worried about what the rise in wave height is going to do to the oil. thinks the storm will pull the oil to the west
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Quoting RecordSeason:
1426:

It is not stationary.

It clearly is accelerating to the NE as it had to move at least a few mph to the ENE to get where it is now since the previous advisory.

You can even check the storm history from wunderground.

They are lying to you. The coordinates prove the storm is accelerating NE to ENE


Or as in many a tropical system in history, the COC relocated? Just throwing that out there. Sounds more logical than a conspiracy theory.
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Quoting RecordSeason:
1426:

It is not stationary.

It clearly is accelerating to the NE as it had to move at least a few mph to the ENE to get where it is now since the previous advisory.

You can even check the storm history from wunderground.

They are lying to you. The coordinates prove the storm is accelerating NE to ENE
You're telling me I should take your word over the NHC? I think not.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting 1900hurricane:

I generally like to divide the Texas coastline into three segments: South, Central, and North. In my book, south extends from the mouth of the Rio Grande up to Corpus Christi Bay generally borders DSTX (Deep South Texas), and can be mostly associated with NWS Brownsville. Middle extends from Corpus Christi Bay to the mouth of the Colorado River, generally borders STX (South Texas), and can be mostly associated with NWS Corpus Christi. North takes up the rest of the coast to the Sabine Pass, generally borders SETX (Southeast Texas), and can be mostly associated with NWS Houston/Galveston. But that may just make sense because I live here... :P


I understand it but I live in SE TX. But our NWS is Lake Charles, La. I think Houston was too busy. Lol.
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ok now the other plane turned around???
Member Since: August 1, 2006 Posts: 28 Comments: 3716
1462. Detrina
Quoting RecordSeason:
1410:

A couple miles per hour and accelerating...


And as for intensity, hey, I didn't make the map. The PHD made the map.

Mets just aren't saying what they know because they are afraid of political backlash, but this is a "catch 22" situation, because there will be hell to pay when Alex makes landfall as a Typhoon Tip sized major in a few days...in Florida...


Hush! I do not want to hear the F word.
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Another great blog from the Doc Meister.
Want to apologize for my error this morning.
It was the Canadian model that was the outlier!
Am sure there are more, but that's the one that is most obvious. Glad to see it is now in the southern landfall regions...

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 From DM Blog.

It's been tough keeping up with this storm and Wimbledon! Have a great evening everyone.
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Alex is just waiting for his tail (Darby) to catch up with him, then he'll wind up.
Member Since: June 27, 2010 Posts: 0 Comments: 760

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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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