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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Barometer bob show and chat
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I dont think the ridge will be as strong to make Alex turn that hard left, will be slow and gentle bend, then the next trough will start to play a role and then that could stall him again, and that could be just offshore and would be devastating
Member Since: July 14, 2008 Posts: 1 Comments: 9625
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.
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Quoting stillwaiting:
whats up HJ??,Is Oz gonna put on his cowboy boots????


Waiting to hear from him. Check his blog on my site for more updates. I'd love to go but vacation is etched in stone! ARRRGGHH!!
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Quoting Patrap:


Noticed it as well Kman.
How goes the Sunset there this evening?


Just peachy thanks !. Had a nice 2 mile walk in cool breezes compliments of Alex. We are drying out here after a few inches of rain the past 4 days.
Member Since: August 19, 2006 Posts: 0 Comments: 15671
hmmm

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Quoting skepticall2:


If I took a jab I didn't mean to. I was upset last year that we had yall this year because your team will be real quick and a tough team next year will be worse for us against yall this year your team has a good chance next year they'll have a great chance.


We'll take this up after fall practice - I'm sure we'll have a Cane injured. (rolls eyes) Can't seem to keep our boys healthy.

Wisconsin beat the crap out of us so I'm obviously worried your DL may manhandle our OL. But your secondary was hit hard by departures and that is our strength.

Aight - back to Alex!
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Quoting Hurricanes101:


thats old



oh ok
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1447. usa777
Quoting CCkid00:

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.

I lived in Bay St Louis Miss. and I clearly remember seeing the NHC saying NOLA was in the bullseye at least 3 days in advance.
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LOL - sorry StormW! I keep posting simultaneous info. :)
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1445. leo305
Quoting MrstormX:


Dude it is stationary...


lets wait and see what the Hunters say
Member Since: April 17, 2010 Posts: 0 Comments: 1753
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Quoting skepticall2:


It is OUR season last time we won a NC we had to go through one of the "best" teams ever so I'm hoping we repeat history this year.
you could always go back and lament on the '06 and '07 seasons...SEC football, the real thing !
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Quoting Tazmanian:
00
URNT12 KNHC 281727
VORTEX DATA MESSAGE AL012010
A. 28/17:07:00Z
B. 20 deg 18 min N
091 deg 44 min W
C. 925 mb 597 m
D. 41 kt
E. 273 deg 27 nm
F. 354 deg 32 kt
G. 272 deg 30 nm
H. EXTRAP 990 mb
I. 21 C / 766 m
J. 23 C / 762 m
K. 21 C / NA
L. NA
M. NA
N. 1234 / 09
O. 0.02 / 1 nm
P. AF306 0501A ALEX OB 19
MAX FL WIND 66 KT NE QUAD 13:23:40Z
SLP EXTRAP FROM 925 MB
SPIRAL BANDING E OF CENTER FIX


thats old
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Quoting Baltimorebirds:
What does this mean.



thats old
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00
URNT12 KNHC 281727
VORTEX DATA MESSAGE AL012010
A. 28/17:07:00Z
B. 20 deg 18 min N
091 deg 44 min W
C. 925 mb 597 m
D. 41 kt
E. 273 deg 27 nm
F. 354 deg 32 kt
G. 272 deg 30 nm
H. EXTRAP 990 mb
I. 21 C / 766 m
J. 23 C / 762 m
K. 21 C / NA
L. NA
M. NA
N. 1234 / 09
O. 0.02 / 1 nm
P. AF306 0501A ALEX OB 19
MAX FL WIND 66 KT NE QUAD 13:23:40Z
SLP EXTRAP FROM 925 MB
SPIRAL BANDING E OF CENTER FIX
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whats up HJ??,Is Oz gonna put on his cowboy boots????
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Barometer Bob's show started: link
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i love you Alex
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I think models will go back north after G4 data
Member Since: July 14, 2008 Posts: 1 Comments: 9625
1432. Patrap
Quoting kmanislander:
The latest advisory says stationary but to me Alex seems to be making a little headway towards 21 N. Once it gets there it will start to clear the headland of the Yucatan which will allow the Eastern semi circle to breate freer and pull moisture without interference from land.

At 22 N it should really start to ramp up.


Noticed it as well Kman.
How goes the Sunset there this evening?
Member Since: July 3, 2005 Posts: 414 Comments: 125418
Quoting nrtiwlnvragn:


Not from a wave. Develops on the trailing end of the trough/front.


So it doesn't develop that wave? Was it the ITCZ disturbance it had on Saturday's run that it just brought north to NC?

I will go look after I eats. Thanks for responding.
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1430. JRRP

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Looks like recon went west of the center.
Member Since: June 9, 2007 Posts: 4 Comments: 15718
The latest advisory says stationary but to me Alex seems to be making a little headway towards 21 N. Once it gets there it will start to clear the headland of the Yucatan which will allow the Eastern semi circle to breathe freer and pull moisture without interference from land.

At 22 N it should really start to ramp up.
Member Since: August 19, 2006 Posts: 0 Comments: 15671
Quoting RecordSeason:
conservative NHC declares it "stationary" because they do not want to admit yet that it is moving N to NNE. They are hoping it changes before next advisory so they don't have to admit it.


Dude it is stationary...
Member Since: May 27, 2009 Posts: 0 Comments: 4355
Also if anyones interested in my opinion of Alex's future.

Link
Alex slowly gaining strength in the Gulf of Mexico 6/28/10

Afternoon all! Alex regained tropical storm status last night and has slowly become better organized over the past 24 hours. Alex is currently located at 20.5N 91.8W moving to the NW at 5 mph. Satellite images show Alex slowly organizing, with cloudtops over the COC and in bands cooling to -80C, a sign of Alex finally moving away from the Yucatan. Recon today found Alex about as strong as it was when it hit the Yucatan on Saturday, with 60 mph tropical storm force winds and a pressure of 990 mb. Alex however has had a problem today with dry air and shear by a ULL to the North of the system. Water Vapor images show a gap between the band to the north of the COC dry air being filtered out of Alex's system. Also Alex's current very low forward speed is causing upwelling underneath the system. Alex needs to get past these barriers in order for any significant intensification to begin.


(Satellite shows Alex trying to become better organized)

The intensity forecast and the track forecast are very hard to predict right now. The intensity of Alex depends on what way it heads. If Alex heads more north than what the National Hurricane Center is predicting, Alex will have more time over water and gain strength. If Alex moves south, vice versa happens. Currently there is a trough situated over the Northeast United States trying to create a weakness to pull Alex more northward, and the ridge behind the trough over the Rocky mountains is trying to build back in. This is where track gets really tricky, if the ridge doesn't build back in time Alex will be influenced more north and a landfall in the Texas / Louisiana area is more likely as favored by the GFS and the GFDL. If the ridge builds back in enough to send Alex into Mexico, Alex will have less time to strengthen and will dissipate over the Mexican mountains as the ECMWF favors. Even if the ECMWF prediction verifies, Alex will still have enough time to at least make it to a high end Category 1 status and probable a 100 mph Category 2 hurricane. Both these predictions I have low confidence in, and I'm in line with the National Hurricane Center's current thinking as a blend of both. I do though in the end suspect Alex might make landfall in extreme southern Texas and have similar effects to the area as Hurricane Dolly did in 2008. Keep in mind though, Alex will be a much larger system than Dolly ever was, and its effects will be felt much more greatly across Texas and Mexico. I also suspect intensity will be in the 100 - 105 mph range for Alex and landfall, as TCHP is deeper as we go more north and wind shear is predicted to lessen up on Alex. Bottom line, it all depends on whether the trough kicks out in time. This is a bad scenario either ways.. and might cause heavy amounts of flooding in Mexico or Texas. All eyes need to be focused on Alex in the next couple of days.


(Current model runs)


(Model intensity forecasts on Alex)

CybrTed
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I would think Alex being stationary would certainly shift the track south. How much would depend on how long it stays that way.
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Why is Jim Cantore in Louisiana?? I'm about to hear his take on all this and the oil spill. Should be entertaining...lol
Quoting homelesswanderer:


Lol. I'm in Vidor. At least MRES after Ike will keep longer than the paper box with peanut butter, crackers and apple juice after Rita. I don't think those were official MRES. lol


Hey neighbors..I'm in Bevil Oaks...I don't know who fed ya'll during Rita but we had some wonderful stuff...boxes and boxes...the absolute best and freshest cinnamon rolls
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Quoting CybrTeddy:
28/1745 UTC 20.2N 91.7W T3.0/3.0 ALEX -- Atlantic
They increased it more than I expected.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
1420. IKE
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'll look.
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Any new models coming out yet? Think they will start going more north or keep it the same?
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1417. leo305
stationary? mhm.. we'll see.. the hurricane hunters are going in as we speculate
Member Since: April 17, 2010 Posts: 0 Comments: 1753
Quoting CanesfanatUT:


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?


Not from a wave. Develops on the trailing end of the trough/front.
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If it drifted NE, I bet the G4 runs will make the models start pointing to Corpus Christi.
Member Since: July 14, 2008 Posts: 1 Comments: 9625
guys do we most keep going overe this



we do not need tchp for a cat 4 or 5 storm


i will name a few

IKE was one of them


and there you have it
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Station 42002 (LLNR 1405) - W GULF 207 NM East of Brownsville, TX
(5:50 pm CDT)
2250 GMT on 06/28/2010:

Wind Speed (WSPD): 21.4 kts
Wind Gust (GST): 23.3 kts
Atmospheric Pressure (PRES): 29.68 in
Air Temperature (ATMP): 83.8 °F
Water Temperature (WTMP): 85.3 °F
Member Since: September 11, 2008 Posts: 0 Comments: 59
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Quoting RecordSeason:
conservative NHC declares it "stationary" because they do not want to admit yet that it is moving N to NNE. They are hoping it changes before next advisory so they don't have to admit it.
It moved 12 miles, LOL! No conservativeness there.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
28/1745 UTC 20.2N 91.7W T3.0/3.0 ALEX -- Atlantic
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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.


Haha - had to respond to your jab at 09 earlier. Yeah - should be a good one. But don't take us lightly - our O is gonna be the best passing offense y'all will see this season.

Can't wait!
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About JeffMasters

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