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: 607 - 557

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

Quoting Levi32:
What is interesting is having the models in excellent agreement now on track....but Alex is not cooperating with the forward speed forecasts, which so far have been way too fast due to his flat-out stalling. If he doesn't get moving tonight, it could change a few things, likely to the south at first, but if he waits even longer than that, it could shift back north. It's just a speculative possibility right now, but we should keep in mind that he is defying the speed forecasts.



the whole basic forecast track was dependant on reliable forward motion. lol

things are going to only get more complicated now and the models do not
perform so well with so many weather systems interacting all at once.

Do you not agree Levi?

Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting caribbeantracker01:
actually alex will become hurricane by 11 pm and i am not certain with the movement but if you look at the weakness in the trof it is pulling alex upwards for the moment this may be short lived however but should the environment become conducive we may see an intensification by mid day tomorrow reaching cat 2 if you observe the tchp to its north it can support an increase in wind speeds reaching just above 96 mph imo but of course i am subjected to error and things can change quickly


I'm thinking low end Cat.5 or high Cat. 4...
Member Since: Posts: Comments:
Quoting BA:


which site is this? accuweather pro or weathertap.com?
Accuweather professional.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting GlobalWarming:
levi, is the african wave behaving as expected?


Yup...it's being a jolly good wave.
Member Since: November 24, 2005 Posts: 635 Comments: 26695
Quoting drg0dOwnCountry:

Maybe the stalling comes from the neuro toxic cocktail.
that's an interesting thought... suppose it's possible the oil might act like an opposing magnet?
Member Since: Posts: Comments:
Quoting Floodman:


Don't hold your breath, but you need but give it about 18 hours or so...a northern component to the motion is possible,but as has been said here numerous times today, the draw will only last so long and with the indeterminate steering right now the window is closing
Thanks Flood~ i'll be watching. gonna be a lllooonnnngggg hurricane season, especially with oil in the gulf. i'm in Denham Springs (between Baton Rouge and New Orleans) and we are getting a hefty thunderstorm right now (the 2nd today) from the outer bands of Alex.
Member Since: Posts: Comments:
Quoting TropicalNonsense:



Soon ALEX will be just a Mexican squall.
LOL I hope so
Member Since: June 13, 2009 Posts: 0 Comments: 6912
599. BA
Quoting MiamiHurricanes09:
Ok, definitely buying that now.


which site is this? accuweather pro or weathertap.com?
Member Since: Posts: Comments:


Member Since: July 3, 2005 Posts: 427 Comments: 129411
Quoting TropicalNonsense:


no. upwelling will occur. Alex looks like SH*T!
wont be a problem for anyone now. Hurricane
Modification 101. ALEX has been Tamed.


Hard to imagine much upwelling unless he stays in realtively shallow water...
Member Since: August 2, 2006 Posts: 10 Comments: 9922



This is very interesting from the NWS....XX..Alex possibility.
Member Since: Posts: Comments:
Quoting scott39:
Its obvious on the last few visible frames that not only is Alex starting to speed up but hes going due N. Also, anybody from the Fl. Panhandle all the way to Mexico needs to stay aware of this developing situation. It could hook left into Mexico,or head for the N Gulf Coast. Models are great but thier not GOD. Nobody on the USA or Mexican gulf coast needs to take thier eye off this potiential monster. Here i already sharpened the blade up for you cut away!



Soon ALEX will be just a Mexican squall.
Member Since: Posts: Comments:
What is interesting is having the models in excellent agreement now on track....but Alex is not cooperating with the forward speed forecasts, which so far have been way too fast due to his flat-out stalling. If he doesn't get moving tonight, it could change a few things, likely to the south at first, but if he waits even longer than that, it could shift back north. It's just a speculative possibility right now, but we should keep in mind that he is defying the speed forecasts.
Member Since: November 24, 2005 Posts: 635 Comments: 26695
Quoting MiamiHurricanes09:
564. HurricaneSwirl 5:43 PM EDT on June 28, 2010

Well satellite presentation isn't so stellar at the time that that was released.


Well it was only an hour ago, plus it looks a lot better one hour ago than uhm, 2 or 3 or 4 or 5 hours ago, so I can understand the weak winds and pressures but not the weakening flag being on.
Member Since: Posts: Comments:
Quoting TropicalNonsense:
Hurricane Modification 101. ALEX has been Tamed. [laughs]
I sure did.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting BiloxiIsle:
Glad to see the models going further south. It's bad enough to deal with a potential hurricane, but I don't want to see what happens when a storm goes over the oil. Hoping all storms stays away from the northern gulf coast for the remainder of the season!

Maybe the stalling comes from the neuro toxic cocktail.
Member Since: Posts: Comments:
Hurricane Modification 101. ALEX has been Tamed! [laughs]
Member Since: Posts: Comments:
actually alex will become hurricane by 11 pm and i am not certain with the movement but if you look at the weakness in the trof it is pulling alex upwards for the moment this may be short lived however but should the environment become conducive we may see an intensification by mid day tomorrow reaching cat 2 if you observe the tchp to its north it can support an increase in wind speeds reaching just above 96 mph imo but of course i am subjected to error and things can change quickly
Member Since: Posts: Comments:
Its obvious on the last few visible frames that not only is Alex starting to speed up but hes going due N. Also, anybody from the Fl. Panhandle all the way to Mexico needs to stay aware of this developing situation. It could hook left into Mexico,or head for the N Gulf Coast. Models are great but thier not GOD. Nobody on the USA or Mexican gulf coast needs to take thier eye off this potiential monster. Here i already sharpened the blade up for you cut away!
Member Since: June 13, 2009 Posts: 0 Comments: 6912
Miami, you have mail!
Member Since: Posts: Comments:
584. xcool
hey tampspin
Member Since: September 26, 2009 Posts: 2 Comments: 15684
This is probably the most logical conversation I have heard about this whole GOM mess.. and its from Billie to boot.
Member Since: October 1, 2007 Posts: 81 Comments: 26512
Quoting MrstormX:
Whos got a fix on the best coordinates...
I don't think anyone does right at the moment....

Taco:o)
Member Since: July 7, 2005 Posts: 6 Comments: 3261
Quoting LSU79:

Well there are are no right or wrongs in here only opnions. And as far as I can tell Alex has managed to shoot holes in just about every opinion in here. So batten down the hatches, get the candles and cards out and hold on this is gonna be one rough ride.


Im in agreement that ALEX has plenty cards to deal before the Tournament is done.
Member Since: July 3, 2005 Posts: 427 Comments: 129411
vis sat loop show new banding on western side of Alex.

http://www.ssd.noaa.gov/goes/flt/t1/flash-vis.html

Could mean that Alex becomes more symmetrical tonight and gains strength to CAT 1 or 2 by morning.
Member Since: Posts: Comments:
564. HurricaneSwirl 5:43 PM EDT on June 28, 2010

Well satellite presentation isn't so stellar at the time that that was released.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Jeff9641:


I just got in a little bit ago and I was just getting ready to look at the upper air patterns. I can see where your statement could be right. Infact i said this earlier in the day but I am starting to second guess myself now. Stalled storms are tricky to deal with.


You're right about all the tropical moisture headed to the southeast. There will be a conveyor belt of moisture setting up ahead of the front and will be enhanced by the large scale onshore flow produced by Alex across much of the Gulf Coast. That coupled with a few short waves riding along the base of the trough itself. High QPF is likely through much of the SE states with Florida big bend area bearing the brunt.
Member Since: Posts: Comments:
Quoting RecordSeason:
Most of Alex*

* I think...


In the later frames you can see the monstrous banding beginning again. You can start to see banding over south MX from moisture in the pacific. It's size will be back shortly.
Member Since: Posts: Comments:
Quoting Houstonia:
My apologies if this has already been posted...

... I thought this was interesting. I don't know much about it, but from what I've heard, his record is pretty good.

Link

British weather forecaster says Alex will move much further north and east...

Piers Corbyn reveals revolutionary forecast concepts. WeatherAction long-range forecasts are produced using Piers Corbyn's Solar Weather Technique which is the most advanced and reliable long-range forecasting system in the world.

The technique uses predictable aspects of solar activity - particle and magnetic effects from the Sun - as the basis for forecasting weather many months and even years in advance. The essence of the technique is explained in scientific presentations (see News Archive).


This forecast is almost 26 hours old....
Member Since: Posts: Comments:
Quoting StormW:


Go the the pro site, click the Satellite imagery section...go to color water vapor, and do the long animation...that will give you a good idea since you can't see the weathertap view.


Look at how far north that ridge is....Idaho...Montana...Wyoming. There's a lot of room to its south for Alex to try to sneak a bit closer to its southern periphery and get into Texas.
Member Since: November 24, 2005 Posts: 635 Comments: 26695
573. CJ5
The COC seen in the 20:45 RGB image is certainly N of where Alex emerged from the coast.

Member Since: Posts: Comments:








Member Since: July 3, 2005 Posts: 427 Comments: 129411
Quoting CCkid00:
So.......i know anything is possible, but a La. hit anywhere is pretty much out of the question now, right? we Louisianians can pretty much breathe easy now, right?


Don't hold your breath, but you need but give it about 18 hours or so...a northern component to the motion is possible,but as has been said here numerous times today, the draw will only last so long and with the indeterminate steering right now the window is closing
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Prepare for explosive intensification and significant yo-yo factor.
Member Since: June 13, 2010 Posts: 0 Comments: 2336
569. BA
what's the point in posting analogs?

unless the conditions are the same for each storm I can't see that it means much that "a storm took this path once"
Member Since: Posts: Comments:
568. JLPR2


Not much going on with the wave, phew! :)
Member Since: Posts: Comments:
There are an awful lot of premature pat on the backs being handed out....YOU ALL ARE GONNA JINX THEM.....LOL
Member Since: Posts: Comments:
Hope they get a nice tail wind to speed them up.
Member Since: September 18, 2007 Posts: 0 Comments: 1074
Most of Alex*

* I think...
Member Since: June 13, 2010 Posts: 0 Comments: 2336
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 28 JUN 2010 Time : 204500 UTC
Lat : 20:28:46 N Lon : 91:47:22 W


CI# /Pressure/ Vmax
3.0 /1001.1mb/ 45.0kt


Final T# Adj T# Raw T#
2.5 2.6 2.6

Latitude bias adjustment to MSLP : +1.1mb

Center Temp : +6.9C Cloud Region Temp : -34.6C

Scene Type : CURVED BAND with 0.38 ARC in LT GRAY
Maximum CURVED BAND with 0.52 ARC in LT GRAY
at Lat: 19:28:11 N Lon: 92:10:48 W

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : FLAG

Ok it was right this morning, but not yesterday afternoon nor now.
Member Since: Posts: Comments:
563. LSU79
Quoting Patrap:


That was a rumor earlier.

But I almost got decapitated for it.

LOL

Well there are are no right or wrongs in here only opnions. And as far as I can tell Alex has managed to shoot holes in just about every opinion in here. So batten down the hatches, get the candles and cards out and hold on this is gonna be one rough ride.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
He emerged yesterday evening and has moved very little.


i wonder how much rain they are getting where its stalled!
Member Since: Posts: Comments:
Quoting Levi32:
New recon just left Louisiana enroute to Alex with arrival about an hour and a half.



can we make them fly a little faster
Member Since: May 21, 2006 Posts: 5091 Comments: 115435
Quoting MiamiHurricanes09:
Convection in and around the center beginning to fire.



Yep, should see this take off tomorrow.
Member Since: Posts: Comments:
Glad to see the models going further south. It's bad enough to deal with a potential hurricane, but I don't want to see what happens when a storm goes over the oil. Hoping all storms stays away from the northern gulf coast for the remainder of the season!
Member Since: Posts: Comments:
So.......i know anything is possible, but a La. hit anywhere is pretty much out of the question now, right? we Louisianians can pretty much breathe easy now, right?
Member Since: Posts: Comments:
Quoting Drakoen:
Slowly becomming better organized


Yup that is more recent and confirms that what is in the last frame on this link: Link is not an eye because convection fills over it. Knew it couldn't be an eye.
Member Since: Posts: Comments:

Viewing: 607 - 557

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.

Local Weather

Overcast
48 °F
Overcast