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: 1207 - 1157

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 StSimonsIslandGAGuy:
Well it's just that Alex is so....big. Big storms don't typically explode in strength.

However Ike was a Cat 2, and we could see something along those lines. But Ike did not make landfall as a major hurricane in Texas. And there is a mindset among some here that a hurricane has to be major to be a real threat. It doesn't. Ike showed that very well.


You want to tell that to all those poor people who's homes were wiped off the map...
Member Since: Posts: Comments:
Good evening everyone! Alex still not doing much to get excited about I see.
Member Since: Posts: Comments:
Quoting StormW:
Ok gang, let's take a breath, and chill...the weakness right now means, that Alex will have a tendency to move in a basic N-NNW direction for about the next 6-12 hours...SLOWLY...Let's not make any SOLID TRACK CALLS until we get the G4 data, and see how the steering layers look in the early morning. There are still MANY variables that have to and will come into play.


Well said StormW. People north of Southern Texas should not be preparing, but watching what Alex does. Southern Texas needs to be preparing since the track is focused just south of them. Take a breather people ;)
Member Since: Posts: Comments:
1203. breald
Quoting TexasHurricane:


hmmmmm - well, I am pretty much right there. About 15 minutes from the LA border. Will definitely be watching....


At this point, I cannot see NHC being that far off from where they are now. If this thing did hit the TX/LA border that would be a huge change from where they currently have it going. I just don't see that happening. IMO.
Member Since: Posts: Comments:
smmcdavid I don't know about you, but I'd feel better for our area if it stays south of Matagorda (which I believe it will)
Member Since: Posts: Comments:
1200. USSINS
Quoting Tazmanian:
can i give Alex a beer


LOL, Taz! I think Alex has been drinking that Mexican water, you know - T E Q U I L L A! ;P
Member Since: Posts: Comments:
1171. smmcdavid 11:25 PM GMT on June 28, 2010
Storm, where's it gonna go?
Storm, how strong will it be?
Storm, what do all those colors mean?
Storm, what's for dinner?
Storm, do you really like us?

:-)
`````~~~~~~~~~~~~~~~~~~~~~

...lol... I tend to ask him a million questions cuz I can't figure out who actually knows what is going on....
Member Since: Posts: Comments:
Quoting CybrTeddy:


What do you think about Alex's current state of organization? Appears to me that its finally starting to move away from the low amounts of TCHP and upwelling, which is why we're seeing that -80C cloudtops forming over the COC.


Well, im not impressed yet. Alex doesnt look like your typical system that wants to pull a round of rapid intensification in its current state. I would like to see it pull away from land some more and see how it looks then.

We'll see how things change later tonight.
Member Since: Posts: Comments:
Quoting Tazmanian:
can i give Alex a beer

Make it Coors Light, I'm having one right now! :)
Member Since: Posts: Comments:
Quoting alaina1085:
We in Louisiana are already feeling Alex. Been raining on and off all day!


same here in Gretna....rain off and on all day
Member Since: Posts: Comments:
Quoting HurricaneSwirl:


Prob more experienced than me haha, but I just wanted to make sure. I think MH09 answered it for us tho.
Turns out it was a NOAA Three-Dimensional Doppler Winds research flight.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
SO how's the 18Z GFDL look?
Member Since: April 1, 2010 Posts: 9 Comments: 2699
Verification?
Looks like the low that was over LA is now over AL? With a break going west then the trailing edge of the trough? (Break, being the weakeness?)

Link
Member Since: Posts: Comments:
1191. Levi32
Quoting CCkid00:

so, a due north movement (to La.), due to the weakness is probably not gonna happen, right? i have family in La. and Houston...(i'm in La.)...hope it doesn't go to either.


A straight north jab into LA isn't likely because this ridge (clockwise spin over the Rockies) is coming eastward and will end up north of Alex in 36-48 hours, which will force him to turn back towards the WNW. I don't think a track as far north as Houston is particularly likely either, but even if Alex comes in at Corpus Christi, his massive size will give Houston a decent chunk of nasty weather on his north side, which will be the worst side for those folks.

Member Since: Posts: Comments:
Quoting xcool:
Tazmanian .i need beer



lol
Member Since: Posts: Comments:
Quoting barbamz:
Another non-tasked recon mission started from Florida.


Thats the NOAA Three-Dimensional Doppler Winds research flight.
Member Since: Posts: Comments:
Quoting smmcdavid:
Storm, where's it gonna go?
Storm, how strong will it be?
Storm, what do all those colors mean?
Storm, what's for dinner?
Storm, do you really like us?

:-)


Lol!!!!
Member Since: Posts: Comments:
1187. USSINS
Quoting Patrap:
# 1096

I just noted the Bi-lobing around the Mean center earlier USSINS..,dats all.

Its always been bigger than the Embedded CoC's that have spun out finally.

Reminds me alot of Lili and Isidore still from Late 02





And, really, that makes perfect sense if folks will think about it - that's the exact way it came ashore.
Member Since: Posts: Comments:
Quoting smmcdavid:
Storm, where's it gonna go?
Storm, how strong will it be?
Storm, what do all those colors mean?
Storm, what's for dinner?
Storm, do you really like us?

:-)


Because we love him so... :)
Member Since: Posts: Comments:
1185. Patrap
Quoting barbamz:


Seems to me it's heading directly to Alex. But I'M not experienced.


The NOAA G-4 is on Station dropping Sondes all around the GOM in a Big Orbit for the Model runs..


Plan of the Day

000
NOUS42 KNHC 271500 COR
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1100 AM EDT SUN 27 JUNE 2010
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 28/1100Z TO 29/1100Z JUNE 2010
TCPOD NUMBER.....10-027 CORRECTION

I. ATLANTIC REQUIREMENTS
1. TROPICAL STORM ALEX
FLIGHT ONE - NOAA 49
A. 29/0000Z
B. NOAA9 0601A ALEX
C. 28/1730Z..........CORRECTED
D. NA
E. NA
F. 41,000 TO 45,000 FT
Member Since: July 3, 2005 Posts: 421 Comments: 127559
1184. IMA
Know what amazes me, but definitely shouldn't? The number of people in San Antonio who don't even know this is out there & are talking about leaving for the Coast or going to Medina Lake as soon as Wednesday or Thursday to start the holiday weekend early.

*Shakes her head at the uninformed, idiotic people who can almost make her look like a genius*

My mother was right, I should've tried harder to get the rest of my things out of the house I shared with my ex, the house that is in the Hill Country, the house that sits where a creek & river meet, the house that flooded once (before we owned it) due to a tropical system. Thank goodness Mom doesn't read this blog, I'd hate for her to see that I said she was right!
Member Since: Posts: Comments:
Quoting barbamz:


Seems to me it's heading directly to Alex. But I'M not experienced.


Prob more experienced than me haha, but I just wanted to make sure. I think MH09 answered it for us tho.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Good Evening. Just got back from watching Toy Story 3. Lol, look at this. GFS shifts north once again. A Corpus Christi landfall, it says.



NAM also says South Texas. (Brownsville)



Most of the convective activity appears to be to the north, however.

But wait...



NAM loops around the system to hit Texas again!

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/nam/18/index_pcp_m_loop.shtml
Member Since: April 1, 2010 Posts: 9 Comments: 2699
Quoting smmcdavid:
Storm, where's it gonna go?
Storm, how strong will it be?
Storm, what do all those colors mean?
Storm, what's for dinner?
Storm, do you really like us?

:-)
He should change his name to spike...
Member Since: Posts: Comments:
Quoting Tazmanian:
can i give Alex a beer
I think he's had too many already considering he is wobbling all over the place.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
1178. CJC111
What's the current thinking on when it will really start to move again? If it continues slow, will that be better for the ridge building back and Alex hooking left?
Member Since: Posts: Comments:
1177. xcool
Tazmanian .i need beer
Member Since: September 26, 2009 Posts: 2 Comments: 15620
1176. barbamz
Quoting HurricaneSwirl:


Is that one of those planes that drops floats in the GOM to determine steering currents for the oil?

Or are you sure this is actually a recon?


Seems to me it's heading directly to Alex. But I'M not experienced.
Member Since: Posts: Comments:
Quoting StormW:


Probably not until late tonight, or early morn.


Sorry -- thanks!!
Member Since: Posts: Comments:
Quoting Tazmanian:
can i give Alex a beer


As long as it's still ice cold to help lower the SST's under him lol.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting xcool:
homelesswanderer big big ififif


Yeah I know. Just wondered if that was right.
Member Since: Posts: Comments:
Quoting RecordSeason:
1120:

what makes you so certain it isn't forming an eye?

It is borderline hurricane wind speed already last time they checked, and this storm had a concentric vortex structure for a long time 24 to 48 hours ago (and probably still does).
Lol, it isn't forming an eye. Just look at satellite, it hasn't even developed a CDO much less an eye.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Storm, where's it gonna go?
Storm, how strong will it be?
Storm, what do all those colors mean?
Storm, what's for dinner?
Storm, do you really like us?

:-)
Member Since: Posts: Comments:
I wish we had some type of access to the on-board radar on the HH plane.

That would be awesome...

Member Since: Posts: Comments:
1169. CCkid00
Quoting Levi32:


Well I don't know about that lol but thank you.

I think the potential for a bit farther north than the NHC has it is definitely there. We'll see how it moves compared to the forecast track during the course of the night. The NHC is near the southern-most portion of my greatest concern area for landfall. I think Alex could get as far north as Corpus Christi or Rockport if he gets moving...but if he maintains a speed this slow and doesn't move as fast as the model forecasts, he could get forced back west sooner and still end up south of Texas. He has to take advantage of the weakness currently to his north for it to be of any worth.

so, a due north movement (to La.), due to the weakness is probably not gonna happen, right? i have family in La. and Houston...(i'm in La.)...hope it doesn't go to either.
Member Since: Posts: Comments:
1168. fsumet
18Z HWRF makes a loop south of Brownsville and then another one just offshore Corpus Christi before moving ashore just north of Corpus Christi in a little over 72 hours.

Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:


Trimming my posts down to take out of context. Nice. I said there was no model support or support from the NHC for a major at this time. It wouldn't shock me if Alex became a major, but I think it is unlikely.

I am going to eat and stay out of the majorcasters' way for a while. Casters get these fixed ideas in their heads and go nuts when someone posts otherwise. Maybe later the blog will calm down.


?

I trimmed your post down to what I thought was it's main point. And I'm not sure how I'm a "majorcaster" when I said it's not the most likely possibility.
Member Since: Posts: Comments:
can i give Alex a beer
Member Since: Posts: Comments:
Quoting StormW:
We'll definitely know more when the G4 data comes out of the models.


when do we expect that?
Member Since: Posts: Comments:
Quoting Stormchaser2007:


What do you think about Alex's current state of organization? Appears to me that its finally starting to move away from the low amounts of TCHP and upwelling, which is why we're seeing that -80C cloudtops forming over the COC.
Member Since: Posts: Comments:
Quoting hunkerdown:
You're right, most of the NHC employees landed those jobs cause they got laid off from the 7-11. Its must better to trust children 3 months out of diapers or those hiding in their mom's basement thinking just cause they know how to post a map or regurgitate what they have read or heard...I feel safe now.


lmao
Member Since: Posts: Comments:
Quoting barbamz:
Another non-tasked recon mission started from Florida.
That isn't a recon mission but rather for the oil spill investigation.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
1161. Cranica
Recon is entering the storm now, let's see if the convective bursts have triggered any pressure falls.
Member Since: Posts: Comments:
1159. Levi32
Quoting homelesswanderer:




Did you mean the storm would go directly to the north on the west side of the ridge that would take it to NOLA? I looked that's what I see. Dunno if that's right.


Steering currents change with time. The map won't look like that tomorrow or the next day. They currently would take Alex north but that ridge over the Rockies is coming east and will turn Alex back towards the WNW eventually, so no it's not going to NOLA.
Member Since: Posts: Comments:
1157. xcool
btwntx08 :0
Member Since: September 26, 2009 Posts: 2 Comments: 15620

Viewing: 1207 - 1157

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

Scattered Clouds
78 °F
Scattered Clouds