Invest 96L: Organizing in the Gulf

By: Dr. Jeff Masters , 1:17 AM GMT on July 08, 2010

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Hi everybody, Dr. Rob Carver filling in for Jeff while he's on vacation.

Invest 96L appears to be in the process of developing into a tropical cyclone. The strength and extent of it's thunderstorms is much improved from yesterday (I used CIMMS tropical storm page for my analysis). It's under an upper-level anticyclone which promotes development because it efficiently removes "exhaust" from the thunderstorms. Shear is relatively low (~10 knots), and SST's are adequate for supporting a tropical cyclone (~28 deg. C). In the most recent Tropical Weather Outlook, NHC mentioned that research flights found that upper-level conditions were promising for storm development, so they assess the chances of 96L of becoming a tropical cyclone at 80%. My take is that 96L has an 80% chance of becoming TD #2, and about a 40% chance of being named Bonnie. My reasoning is that 96L has about 24 hours to intensify before interactions with land start interfering with intensification processes. Also, model intensity forecasts are not very supportive of 96L attaining tropical storm force winds. The model track forecast aids have 96L's center of circulation making landfall somewhere between Brownsville and Corpus Christi.

Impacts
The 12Z operational GFS, HWRF, NOGAPS, and 18Z NAM tell a similar story about the surface winds. Near tropical-storm force winds affect the Texas coast from Corpus Christi to Matagorda Bay. A broad area of 30+ mph winds also affects the Deepwater Horizon oil spill recovery efforts. The 12Z Canadian global model downplays the wind strengths, and the 12Z parallel GFS fails to develop any significant surface wind (> 20 mph). That said, I believe that 96L's greatest impact will be in the form of rain.

The Rio Grande from Del Rio to Laredo is either at major flood stage or is forecast to reach major flood stage in the next 24 hours. This is due to Alex and the moisture he brought to the high terrain of northern Mexico. Nearly all of the forecast models I've looked at forecast 2-3 inches of rain over the Rio Grande Valley in the next 5 days. That will only encourage more flooding. The main forecast problem is how much rain will fall along the Gulf Coast. The parallel GFS and HWRF suggest that 4.5 to 6.5 inches of rain will fall in the Galveston/Houston area in the next 5 days. In my opinion, people living in this area should be prepared for flooding.


Fig. 1. 120 hr accumulated precipitation (mm) for 12Z parallel GFS. Operational GFS


Fig. 2. 120 hr accumulated precipitation (mm) for 12Z HWRF.


Fig. 3. 120 hr accumulated precipitation (mm) for 12Z Canadian global model. NOGAPS

Emergency Preparations
People living along the Gulf coast from south of the Rio Grande to the Texas/Louisiana border should review their emergency preparations (hurricane preparations also make for good flood preparations). Jeff has put together a guide to hurricane preparedness with plenty of links for more information.

Next Update
If 96L becomes TD2 or Bonnie, I'll have an update tonight. Shaun Tanner may post something in the morning if that's when the naming occurs. Otherwise, I'll post a tropical update tomorrow afternoon.

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Quoting texwarhawk:
theres a nice looking wave south of jamaca north of columbia- its a little south but moving north. Posibly somthing to look at imo

Isn't this the same Twave that was part of 96L and the Yellow Circles this weekend? Looks like it's trying to jumpstart a solo career...
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124NM KBRO NEXRAD

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Also, I'm thinking Stewart is letting the new guy, Canglialosi, "have his head" a bit more. Maybe? Personally I think they were prolly a bit pre-mature in calling it on the basis of their usual standard of TD, but mainly because it's aimed for that same area where the flooding is currently so bad.
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Quoting StormW:


Well, I don't know what the satellite presentation showed at 11:00 p.m., however I'm not too particularly impressed at the moment. NHC may have had enough criteria based on satellite and recon, but with the convection waning a few hours ago, I still believe recon will find a T.D. The only way I see this making it to TS status, is if the convection keeps building over the COC as it's doing. Shortwave IR indicates a well defined circulation, so I feel the convection could be the issue hear. I must say though, I'm less than impressed at the moment, given the past 3 seasons with the NHC consistency in classification.
Morning, StormW. I was wondering what your take on it would be... Ike, reedzone and a few others have been laughing themselves all over the blog since about 11 p.m. last night.

It looks like it may have just enough time to develop some convection over the COC before it hits land. Amazing that after all this 96L may not even make it to named storm status...
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storms are firing up over the center as we speak
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theres a nice looking wave south of jamaca north of columbia- its a little south but moving north. Posibly somthing to look at imo

Member Since: July 7, 2010 Posts: 4 Comments: 203
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Can this be considered an "outer band" of TD2? ;o)

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Quoting btwntx08:
thought i wake up too and yes convective blow up over the coc also u can see it on radar as well
I'm kinda glad this is as close to the coast as it is, giving it a little less time to tighten up and fill in before landfall....
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Convection at the southern end of the ULL / potential subtropical entity off the US east coast....

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Quoting texwarhawk:
seems like theres some action brewing near COC

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seems like theres some action brewing near COC
Member Since: July 7, 2010 Posts: 4 Comments: 203
Morning all. Couldn't sleep anymore, so thought I'd look in on TD2....

Quoting NCHurricane2009:


I see what you are saying. Is there a surface low center under the ULL? If so, perhaps subtropical cyclone development possible. If not, this has got a long way to go.

I have been watching this cut-off ULL since July 4th, it needs a consolidated surface low pressure center to develop though.
It's been meandering around out here since then, u are right. I think there's been enough persistence for us to end up with something sub-tropical in the area. I don't expect for NHC to post anything on it invest-wise before tomorrow, though, if they post anything at all. Right now it seems they have a pretty clear sense that any tropical development is not currently in the works.
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hi storm w.. whats your take on things with TD-2?
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TropicalDepressionTwo was^heading toward SouthPadreIsland,Texas landfall in 9hours.
(Straightline^projection using its last 2 positions. Take with HUGE grain of salt)

Copy&paste 23.9N93.9W, 24.3N94.5W-24.8N95.2W, 24.8N95.2W-26.4N97.5W, TAM, MOB, PBI, SAL, 28.7N88.4W into the GreatCircleMapper

Shortest red line denotes the movement between last two positions. Below the map shows:
TD2 had a heading of 308.1degrees (6.9degrees west of NorthWest) while traveling
a distance of 56miles(~90.2kilometres) over 3hours at a speed of ~18.7mph(~30k/h),
and was 181miles(~290.4kilometres) away from the coast in the direction of its heading.

^ Straightline projections are not forecasts of what will happen in the future,
especially not for TropicalCyclones. They aftcast what has already happened.
* DeepwaterHorizon is marked at 28.7N88.4W
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THE PRIMARY THREAT WITH THIS SYSTEM IS HEAVY RAINFALL. THESE RAINS
ARE FORECAST TO OCURR ON TOP OF ALREADY SATURATED GROUND AND
RAIN-SWOLLEN CREEKS AND RIVERS ACROSS PORTIONS OF SOUTHERN TEXAS
AND NORTHEASTERN MEXICO CAUSED BY FORMER HURRICANE ALEX.

TD2 or remnant trough, this is the take-away point for this system. We have to be on standby for rainfall in Alex-saturated grounds.

Glad I declared its possible it couldn't become Bonnie on my blog. Yepper, this one is similar (but not the same) to TD 11 of 1999 as I discuss on my blog.

With that, I am signing off, G'night/morning to all the insomniacs!
Member Since: September 15, 2009 Posts: 437 Comments: 3600
967. IKE
Quoting robert88:
The NHC must think it's going to slow down some. That graph above still looks wrong to me.


LOL....they don't have it making landfall til after 1pm? No way it stays offshore that long.

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I think that once the sun rises it might give it the energy to build before landfall. JMO
Member Since: July 7, 2010 Posts: 4 Comments: 203
965. IKE
Quoting robert88:
AFTER A PERIOD OF DEVELOPMENT DURING WEDNESDAY AFTERNOON AND EVENING...THE DEEP CONVECTION NEAR THE CENTER OF THE DEPRESSION HAS PRACTICALLY VANISHED. LOL

What do you guys think RECON will find???


I don't think they'll find a TS....either a TD or dissipated.
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The NHC must think it's going to slow down some. That graph above still looks wrong to me.
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AFTER A PERIOD OF DEVELOPMENT DURING WEDNESDAY AFTERNOON AND EVENING...THE DEEP CONVECTION NEAR THE CENTER OF THE DEPRESSION HAS PRACTICALLY VANISHED. LOL

What do you guys think RECON will find???
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960. IKE
Quoting NCHurricane2009:
Okay, NHC's justification for keeping it a TD:

HOWEVER...IT IS NOT UNCOMMON TO HAVE FLUCTUATIONS IN CONVECTION
DURING FORMATIVE STAGE.

...and they're waiting for recon aircraft before wanting to declare it dissipated:

A RECONNAISSANCE AIRCRAFT WILL BE IN THE
AREA IN TWO OR THREE HOURS AND WILL HELP TO DETERMINE THE STATUS OF
THE SYSTEM.

That's what I read between their lines.


Exactly.
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959. IKE
Sounds to me from reading Avila's discussion he's not 100% sure if...it's still a depression. They better get recon in there ASAP before it reaches the coast.
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Okay, NHC's justification for keeping it a TD:

HOWEVER...IT IS NOT UNCOMMON TO HAVE FLUCTUATIONS IN CONVECTION
DURING FORMATIVE STAGE.

...and they're waiting for recon aircraft before wanting to declare it dissipated:

A RECONNAISSANCE AIRCRAFT WILL BE IN THE
AREA IN TWO OR THREE HOURS AND WILL HELP TO DETERMINE THE STATUS OF
THE SYSTEM.

That's what I read between their lines.
Member Since: September 15, 2009 Posts: 437 Comments: 3600
957. IKE
TROPICAL DEPRESSION TWO DISCUSSION NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022010
400 AM CDT THU JUL 08 2010

AFTER A PERIOD OF DEVELOPMENT DURING WEDNESDAY AFTERNOON AND
EVENING...THE DEEP CONVECTION NEAR THE CENTER OF THE DEPRESSION HAS
PRACTICALLY VANISHED. ONLY A FEW THUNDERSTORMS ARE CURRENTLY
OBSERVED ON THE SOUTH AND EAST SIDES OF THE CIRCULATION.
HOWEVER...IT IS NOT UNCOMMON TO HAVE FLUCTUATIONS IN CONVECTION
DURING FORMATIVE STAGE. A RECONNAISSANCE AIRCRAFT WILL BE IN THE
AREA IN TWO OR THREE HOURS AND WILL HELP TO DETERMINE THE STATUS OF
THE SYSTEM. AT THIS TIME...IT IS ASSUMED THAT THE INTENSITY REMAINS
AT 30 KNOTS. SINCE THE GULF WATERS ARE WARM AND THE UPPER-LEVEL
ENVIRONMENT IS NOT HOSTILE...A RETURN OF THE CONVECTION IS
EXPECTED. IF SO...THE DEPRESSION COULD STILL HAVE A SMALL CHANCE TO
BECOME A TROPICAL STORM BEFORE MOVING INLAND WITHIN THE WARNING
AREA LATER TODAY. THEREFORE...THE TROPICAL STORM WARNING HAS BEEN
KEPT IN THIS ADVISORY. NONE OF THE INTENSITY GUIDANCE SHOW
IMPORTANT STRENGTHENING.

BOTH...INITIAL LOCATION AND MOTION ARE HIGHLY UNCERTAIN. THE BEST
ESTIMATE OF THE MOTION IS TOWARD THE NORTHWEST OR 310 DEGREES AT 12
KNOTS. THE DEPRESSION IS BEING STEERED BY THE FLOW AROUND A
PERSISTENT MID-LEVEL RIDGE OVER THE SOUTHERN UNITED STATES. THIS
FLOW PATTERN WILL MAINTAIN THE CYCLONE ON THIS TRACK UNTIL
DISSIPATION OVER LAND IN ABOUT 36 HOURS.

THE PRIMARY THREAT WITH THIS SYSTEM IS HEAVY RAINFALL. THESE RAINS
ARE FORECAST TO OCURR ON TOP OF ALREADY SATURATED GROUND AND
RAIN-SWOLLEN CREEKS AND RIVERS ACROSS PORTIONS OF SOUTHERN TEXAS
AND NORTHEASTERN MEXICO CAUSED BY FORMER HURRICANE ALEX.


FORECAST POSITIONS AND MAX WINDS

INITIAL 08/0900Z 24.8N 95.2W 30 KT
12HR VT 08/1800Z 25.8N 96.7W 35 KT
24HR VT 09/0600Z 26.5N 99.0W 25 KT...INLAND
36HR VT 09/1800Z...DISSIPATED

$$
FORECASTER AVILA

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From the NHC June summary:

000
ABNT30 KNHC 011127
TWSAT
MONTHLY TROPICAL WEATHER SUMMARY
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT THU JUL 01 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

HURRICANE ALEX WAS THE ONLY TROPICAL CYCLONE OBSERVED DURING THE
MONTH OF JUNE AND THE FIRST JUNE ATLANTIC BASIN HURRICANE SINCE
1995. IT WAS ALSO THE FIRST CATEGORY TWO JUNE HURRICANE SINCE 1966.
ON AVERAGE...A TROPICAL STORM OCCURS IN THE ATLANTIC BASIN IN JUNE
EVERY OTHER YEAR...AND A HURRICANE ABOUT ONCE EVERY FIVE YEARS. ALEX
MADE LANDFALL ALONG THE NORTHEAST MEXICAN COAST IN THE MUNICIPALITY
OF SOTO LA MARINA LATE ON 30 JUNE AS A CATEGORY TWO HURRICANE ON
THE SAFFIR-SIMPSON HURRICANE WIND SCALE.

REPORTS ON INDIVIDUAL CYCLONES...WHEN COMPLETED...ARE AT THE WEB
SITE OF THE NATIONAL HURRICANE CENTER...USE LOWER-CASE
LETTERS...HTTP://WWW.NHC.NOAA.GOV/2010ATLAN.SHTML

SUMMARY TABLE

NAME DATES MAX WIND (MPH)
----------------------------------------------------
H ALEX 25 JUN- 105

$$
FORECASTER BLAKE

Usually the monthly summary tells you whether or not they will reconsider a system. Looks like they aren't reconsidering 92L. Lets see if the July summary will reconsider 95L.
Member Since: September 15, 2009 Posts: 437 Comments: 3600
955. IKE
...TROPICAL DEPRESSION EXPECTED TO BRING RAINS TO SOUTHERN TEXAS AND NORTHEASTERN MEXICO....
4:00 AM CDT Thu Jul 8
Location: 24.8°N 95.2°W
Max sustained: 35 mph
Moving: NW at 14 mph
Min pressure: 1006 mb
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Oh by the way, if this thing is kept a TD by the NHC by 5 AM, I wonder what their justification would be during their advisory discussion.

LOL, maybe they have a wishcaster down there tonight, LOL.
Member Since: September 15, 2009 Posts: 437 Comments: 3600
Quoting NCHurricane2009:
robert88, did you also think 95L was a TD the other day?

There were also some satellite frames on July 4 that showed nice circular storm bursts at the center for hours, and then they went crazy over it on the afternoon of July 5, saying winds of just under TS force were approaching Terrebone Parish, LA (in a Special Tropical Weather Outlook issued on 5:10 PM, July 5).


Yeah i know. It was a very small circulation but it sure did have some nice convection around the COC. I think it was at least a TD or 40mph minimal TS and it looked better than TD 2. It sure looked like it had a closed circulation on satellite to me. I think 92 and 95L deserve to be upgraded at the end of the year.
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This seeming inconsistency is why I never listen to those who say the increased tropical cyclone activity in recent years is because of global warming. What about 1933? Without any satellite data, there were 21 tropical cyclones detected. Imagine with satellite imagery, they could have found more that year.

And they keep on doing this, there are different justifications for declaring each system (sometimes a satellite scan of winds, sometimes satellite apperance, sometimes recon obs, sometimes ship reports/surface obs). Without a consistent method of declaring tropical cyclones, you don't know for sure how many each year. So, without a consistent record of for sure how many TCs we've had each year going way way back, you can't tell if increased TCs are due to global warming.

A lot of the variability is due to things like AMO, El Nino/La Nina, etc.
Member Since: September 15, 2009 Posts: 437 Comments: 3600
robert88, did you also think 95L was a TD the other day?

There were also some satellite frames on July 4 that showed nice circular storm bursts at the center for hours, and then they went crazy over it on the afternoon of July 5, saying winds of just under TS force were approaching Terrebone Parish, LA (in a Special Tropical Weather Outlook issued on 5:10 PM, July 5).
Member Since: September 15, 2009 Posts: 437 Comments: 3600
Quoting NCHurricane2009:
This seems controversial. The reason they declared TD 2 is because of recon aircraft investigations and not satellite appearance (by Dvorak numbers, etc.). Other times, they'll go off of satellite appearance and not recon, so how do you know for sure if other weak cyclones like TD 2 have been missed because they couldn't fly recon into it (i.e. like a system in the far E Atlantic with a spin like TD 2's)?


Exactly!!! I think 92L was a TD for quite a while imo I have seen this inconsistency so many times over the years.
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Quoting robert88:
Now if they upgrade this mess to Bonnie i am going to have to purchase a plane ticket to Miami and join in on that circle down there LOL


Dude, I said that about Jerry 2007. Does anyone else remember that one. Looked like total junk on the sat., but they upgraded it based on a satellite scan of winds.
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947. IKE
Quoting NCHurricane2009:
This seems controversial. The reason they declared TD 2 is because of recon aircraft investigations and not satellite appearance (by Dvorak numbers, etc.). Other times, they'll go off of satellite appearance and not recon, so how do you know for sure if other weak cyclones like TD 2 have been missed because they couldn't fly recon into it (i.e. like a system in the far E Atlantic with a spin like TD 2's)?


I agree with you.
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Now if they upgrade this mess to Bonnie i am going to have to purchase a plane ticket to Miami and join in on that circle down there LOL
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945. JRRP
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This seems controversial. The reason they declared TD 2 is because of recon aircraft investigations and not satellite appearance (by Dvorak numbers, etc.). Other times, they'll go off of satellite appearance and not recon, so how do you know for sure if other weak cyclones like TD 2 have been missed because they couldn't fly recon into it (i.e. like a system in the far E Atlantic with a spin like TD 2's)?
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943. IKE
Quoting robert88:


Must of got a hold of the skunky funky heh LOL Let's just hope everything is all good over there when August and September arrive.


LOL...yeah...really....I can't believe they designated this...




Quoting NCHurricane2009:
One more hour to see if the next advisory declares TD2 dead. If not dead by 5 AM, dead by 11 AM.


I'm gonna stay up and wait on it.
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Quoting IKE:


That...or Stewart and his new buddy found some tree to burn...if ya know what I mean and thought they saw something with...I hate to even call it a TD.


From the 1am advisory....

...TROPICAL DEPRESSION REMAINS POORLY ORGANIZED...

Ya think?


Must of got a hold of the skunky funky heh LOL Let's just hope everything is all good over there when August and September arrive.
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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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