Invest 95L Brushes Louisiana Coastline

By: Dr. Jeff Masters , 12:42 AM GMT on July 06, 2010

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Hi all,

Dr. Rob Carver, filling in for Jeff this week.

Midnight CDT Update
The low known as Invest 95L stopped it's northward progression and is now moving west along the Louisiana coastline. This is the oddest mesoscale convective complex/tropical feature I've seen in awhile. It's still producing a lot of rain, 2+ inches inland and 6+ inches over the ocean.


Base reflectivity from Lake Charles, LA at 11PM July 5 showing a very nice comma head. Animated loop.


Invest 95L is making landfall now in southern Louisiana near Terrebonne Bay. A CMAN station in Terrebonne Bay is currently reporting winds from the SE at 21 mph and the pressure is 1009 mb. Looking at the radar data, Invest 95L never had convection around the center of circulation. Also, it was hard to see a distinct surface circulation in the different analyses available. I believe soaking rains for southern Lousisana are going to be Invest 95L's main legacy. It's already produced 5+ inches of rain in some offshore locations according to radar-derived rainfall estimates.


Fig. 1 Meteogram for TRBL1 in Terrebonne Bay, LA. Tabular data are here.


Fig. 2 Base reflectivity from New Orleans, LA at 706PM, July 5. Animated loop.

Invest 96L
430 AM Update
In sum, the 00Z model runs don't present a different picture. It is curious to note that the Canadian Global model does not intensify 96L at all in the 00Z run, while NOGAPS has shifted towards a SE Louisiana landfall. I think the following discussion is still valid.

96L is going to be an interesting feature to forecast. It's still on the edge of a strong wind shear gradient. 40+ knots of shear are on the NE side of 96L, and <10 knots are on the SW side. The "center" of 96L is under about 15 knots of shear. This is likely inhibiting 96L. Nearly all forecast models take 96L NW through the Yucatan peninsula and into the Gulf of Mexico. Near the Yucatan itself, sea-surface temperatures are relatively cool, not the best environment for intensification. However, at 25N, 87W there is a hotspot of SST's, which would promote rapid intensification. However, there's currently 20 knots of shear over the hotspot, so the thunderstorms that do form as a result will be well ventilated, and not cause 96L to intensify.

The dynamical models have different takes on how 96L intensifies in the next 120 hours. The 18Z operational GFS strongly intensifies 96L over the hotspot and takes 96L towards Grand Isle, LA. The parallel (for testing model configuration changes) GFS has a similar track, but does not strengthen 96L as much. This indicates uncertainty on how the models are handling the upper-level winds.

The 18Z HWRF solution is much like the parallel GFS solution. The 12Z Canadian global model has a more westerly track, pushing 96L towards Port Arthur, but it strengthens 96L right before it makes landfall, not when it's over open water. NOGAPS takes the "a little from column A, a little from column B" approach, with a spinup over the hotspot (op. GFS solution), but a westerly landfall (the Canadian solution). More data to initialize the models from synoptic reconnaissance flights will help reduce uncertainty.

The bottom line, 96L will move into the Gulf of Mexico and is then shrouded by the mists of uncertainty. I also think that it's a possibility (>50%) that it will become a tropical cyclone sometime in the next 48-72 hours (leaning towards sometime in day 2-3 based on the model runs.)


Fig. 3 Plot of maximum winds (mph) for the next 120 hours from the 18Z July 5 GFS model run.Parallel GFS version.


Fig. 4 Plot of maximum winds (mph) for the next 120 hours from the 18Z July 5 HWRF model run.


Fig. 5 Plot of maximum winds (mph) for the next 120 hours from the 12Z July 5 CMC global model run.NOGAPS wind swath.

Next update
I'll probably tweak this blog later tonight as new model runs come in. I'll have a full update tomorrow afternoon (Pacific time).

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Quoting hydrus:
I am from S.W.Florida. I have been through a few too many myself. I have watched your region get slammed over the years also. The most memorable being Frederick in 1979. And Ivan in 04. Danny in 97 did some damage too.


Yeah, Frederic is our hurricane barometer around here. Spent 3 hours in the eye wall of that SOB.....at night....very unpleasent.
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local NWS doesn't seem concerned by the low pressure off the coast...

NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC
1000 AM EDT TUE JUL 6 2010

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE OFFSHORE THROUGH WEDNESDAY. A WEAK AREA
OF LOW PRESSURE WILL APPROACH FROM THE EAST THURSDAY THEN LIFT
NORTH AND SLOWLY DISSIPATE FRIDAY. A COLD FRONT WILL APPROACH
FROM THE NORTHWEST SATURDAY THEN STALL OVER THE REGION SUNDAY AND
DISSIPATE THROUGH MONDAY.
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Quoting IKE:
Moisture getting pulled north just like the models on Monday were calling for...

Good afternoon Ike.Is it possible 96l can be picked up by the moisture from 95l and pull it Northward?
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1317. IKE
Quoting HurricaneSwirl:
invest_DEACTIVATE_al952010.ren

Took 'em a little longer than I thought they would.


*We are gathered here today to honor an invest that put teh WU blog community in fight mode. It deserved the honor of being a TD, even after we were told to forget about it. You gave it your all 95L/TD2/Bonnie?, and we honor you.*

IKE will make a $10 donation to the...designate 95L a TD...fund! Checks in the mail!
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1. A BROAD AREA OF LOW PRESSURE OVER THE NORTHERN YUCATAN PENINSULA AND
THE SOUTH CENTRAL GULF OF MEXICO IS PRODUCING A LARGE AREA OF
DISORGANIZED SHOWERS AND THUNDERSTORMS OVER THE NORTHWESTERN
CARIBBEAN SEA...THE YUCATAN PENINSULA...AND PORTIONS OF THE EASTERN
GULF OF MEXICO. ENVIRONMENTAL CONDITIONS APPEAR MARGINALLY
CONDUCIVE FOR SLOW DEVELOPMENT OF THIS SYSTEM AS IT MOVES
WEST-NORTHWESTWARD AT 10 TO 15 MPH. THERE IS A MEDIUM CHANCE...30
PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINFALL
AND GUSTY WINDS ARE POSSIBLE OVER PORTIONS OF THE YUCATAN PENINSULA
THROUGH TONIGHT.
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Cape Verde season will very soon make itself known; somebody had indicated that GFS grows a CV storm soon?
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Quoting saintsfan06:
I don't normally contribute to "online" requests but I must say I have given to Portlight, mainly because of Press and his passion for helping others. Not sure about his "contoversial" political views and don't really care. Everyone has said things that rub some the wrong way. It is a blog for pete's sake and during slow times what else is there to talk about!! I personally miss his comments here.


Me too.
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Quoting IKE:
Moisture getting pulled north just like the models on Monday were calling for...



Does that mean anything as far as developing?
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invest_DEACTIVATE_al952010.ren

Took 'em a little longer than I thought they would.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
1311. IKE
Moisture getting pulled north just like the models on Monday were calling for...

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting IKE:
HWRF@12Z on 96L.


Looks like HWRF is still hanging on to it.. but then again, according to the HWRF a couple days back it was supposed to be a hurricane by this time, so yeah. Weak TS fizzles into a TD right before landfall. That's kinda where I am right now except I don't think it'll weaken to a TD before landfall.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
No percentage upgrades will be made to this tropical wave crossing the Yucatan for another 24 hours. In the meantime, expect it to stay orange (30%). Any circulation is broad and poorly organized and if there is going to be any classification of this "so-called" 96L, it better tighten up and start exhausting when it moves out over the Southern Gulf.
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1307. IKE
Quoting rmbjoe1954:

12Z GFDL fizzles out 96L. Oh well, perhaps NHC will give it 60% tomorrow morning and than 0% at 2pm. Government can do no wrong!


LOL!
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1306. IKE
HWRF@12Z on 96L.
Member Since: June 9, 2005 Posts: 23 Comments: 37858

12Z GFDL fizzles out 96L. Oh well, perhaps NHC will give it 60% tomorrow morning and than 0% at 2pm. Government can do no wrong!
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Lol I can't wait for all the RIPers, I still think this will become Bonnie, probably one of the few left. Not saying this will be a 2005, as 2005 was getting ready to spit out the "E" storm 5 years ago so yeah.. definitely don't think we're catching that year.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting IKE:


Also....they reserve the right to make a BIG pct. change and then change it back to what it was before....all within 3 hours.


LOL.....
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Quoting IKE:


Also....they reserve the right to make a BIG pct. change and then change it back to what it was before....all within 3 hours.

Yep, that too. lol
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1301. IKE
Quoting washingaway:
NHC Footnote: We reserve the right to change the percentage at any time, with little or no warning!


Also....they reserve the right to make a BIG pct. change and then change it back to what it was before....all within 3 hours.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
I doubt they raise the chances. They will most likely keep it the same. 96L is a mess and it also has unfavorable conditions ahead. I would give it maybe a 5% chance of reaching a TD status. Looking like a very typical July out there in the Atlantic basin. Strong HP has whipped up a lot of SAL and some dry sinking air. Shear is also more moderate than it was in June. We are in a quiet pattern and should stay that way for another 7-10 days.
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Quoting washingaway:
NHC Footnote: We reserve the right to change the percentage at any time, with little or no warning!

Yep, we noticed. LOL.
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Nice Spin with the TW near 40w.
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NHC Footnote: We reserve the right to change the percentage at any time, with little or no warning!
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1296. IKE
12Z GFDL on 96L.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
I have high confidence in seeing at least Tropical Depression two in the GOM by the end of the week. 96L seems to be right over Cancun, and should be in the GOM by tomorrow. The system remains disorganized, but outflow has improved since this morning (in my opinion). 95L (TD?) is well inland in LA, I still question the NHC judgement on that little cridder. Other then that, nothing else going on.. wait.. There is a NON-TROPICAL low sitting, spinning off the East Coast. This is the time of year where they can acquire Subtropical Characteristics. So that will be watched thru-out the week. Nothing else to note, a few waves, but wind shear and dry air remains in tact... for now.
Member Since: July 1, 2008 Posts: 13 Comments: 7396
How did all of your TWOs get updated so quickly LOL, mine was showing the 8AM until just now XD
Member Since: July 7, 2008 Posts: 2 Comments: 3237
1293. hydrus
Quoting StormSurgeon:


I was being facetious, NOGAPS is unreliable beyond 30-40 minutes. Besides, I'm 51, in Mobile and been through more storms than I care to remember. Been interested in and studying these things since Camille in 69.
Avila calls me for my approval of his updates......right.
I am from S.W.Florida. I have been through a few too many myself. I have watched your region get slammed over the years also. The most memorable being Frederick in 1979. And Ivan in 04. Danny in 97 did some damage too.
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1292. Patrap
96L Enhanced Infrared (IR) Imagery (4 km Mercator)
1702 UTC




4km Remapped Color Enhanced Infrared Imagery

Current imagery and loops of 4km remapped and color enhanced infrared (IR) imagery is displayed in an earth fixed coordinate system. IR imagery (~11 um) from five geostationary satellites are remapped to a common 4km resolution Mercator projection in an identical manner as the CIRA Tropical Cyclone Image Archive described in (Mueller et al. (2006) . These images are then centered and displayed using the nearest 5 degree latitude/longitude earth coordinate based on the most recent location and past 12-h movement.
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Right now I see no reason to increase the 30 percent. Very strong High Pressure in Eastern U.S. will steer 96L West or Northwest.
Member Since: July 5, 2009 Posts: 0 Comments: 1348
I think they'll keep it at 30%, but I do think I see some pretty defined spin on the visible centered around 20.5 88.5
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Quoting HurricaneSwirl:
It's not going code red today.. 30% at 2PM.. then 30% at 8PM probably. MAYBE by this time tomorrow it'll get to 50% but I think a lot of people are trying to speed up a process that can't be sped up especially while it's over land. I mean its vort max is way in the central gulf, needs to get stacked first.


It needs to move over water as well if it wants to intensify.
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Quoting StormSurgeon:


....if you see him, you're in trouble.....if you don't, your dead......LOL


lol, Got to watch the fist that comes from his chin, its deadly.
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1287. Patrap
96L Viz 1710 UTC

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It's not going code red today.. 30% at 2PM.. then 30% at 8PM probably. MAYBE by this time tomorrow it'll get to 50% but I think a lot of people are trying to speed up a process that can't be sped up especially while it's over land. I mean its vort max is way in the central gulf, needs to get stacked first.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting saintsfan06:
I don't normally contribute to "online" requests but I must say I have given to Portlight, mainly because of Press and his passion for helping others. Not sure about his "contoversial" political views and don't really care. Everyone has said things that rub some the wrong way. It is a blog for pete's sake and during slow times what else is there to talk about!! I personally miss his comments here.


Well said...
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You all are right.
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1283. IKE
ENVIRONMENTAL CONDITIONS APPEAR MARGINALLY
CONDUCIVE FOR SLOW DEVELOPMENT OF THIS SYSTEM AS IT MOVES
WEST-NORTHWESTWARD AT 10 TO 15 MPH. THERE IS A MEDIUM CHANCE...30
PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.


Now their just "marginally conducive".
Member Since: June 9, 2005 Posts: 23 Comments: 37858
000
ABNT20 KNHC 061743
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT TUE JUL 6 2010

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

A BROAD AREA OF LOW PRESSURE OVER THE NORTHERN YUCATAN PENINSULA AND
THE SOUTH CENTRAL GULF OF MEXICO IS PRODUCING A LARGE AREA OF
DISORGANIZED SHOWERS AND THUNDERSTORMS OVER THE NORTHWESTERN
CARIBBEAN SEA...THE YUCATAN PENINSULA...AND PORTIONS OF THE EASTERN
GULF OF MEXICO. ENVIRONMENTAL CONDITIONS APPEAR MARGINALLY
CONDUCIVE FOR SLOW DEVELOPMENT OF THIS SYSTEM AS IT MOVES
WEST-NORTHWESTWARD AT 10 TO 15 MPH. THERE IS A MEDIUM CHANCE...30
PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINFALL
AND GUSTY WINDS ARE POSSIBLE OVER PORTIONS OF THE YUCATAN PENINSULA
THROUGH TONIGHT.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BROWN
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Quoting StormChaser81:


Chuck Norris can go invisible if he needs to.


....if you see him, you're in trouble.....if you don't, your dead......LOL
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96L doesn't seem to be moving much.
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1279. IKE
Looks rather stretched out....like the models yesterday were saying it would be...

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting tropicfreak:


Structure-wise though, looking very impressive.


Your just seeing cirrus outflow. It's still poorly organized with no banding features or evidence of decent structure underneath the cloud cover.

The atmosphere around 96L is very moist and doesn't take much to have a huge burst of convection here and there.
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Quoting hydrus:
50% And then later tonight to 60%..jmo


50%
Member Since: June 2, 2010 Posts: 0 Comments: 1348
Quoting hydrus:
This is only the beginning S.S. Wait until the the massive hurricanes start come rolling through on a regular basis.


I was being facetious, NOGAPS is unreliable beyond 30-40 minutes. Besides, I'm 51, in Mobile and been through more storms than I care to remember. Been interested in and studying these things since Camille in 69.
Avila calls me for my approval of his updates......right.
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Throw six darts and you will get six storms

Quoting StormSurgeon:


Get a map of the W. Hemisphere, tack to the wall, stand back 30 feet, throw a dart and your solution will be as accurate.
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1274. IKE
96L....

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting IKE:


Stay at 30%...convection fading some over the Yucatan.


yeah, no upgrade over the Yucatan....maybe not over the GOM as well...
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I don't normally contribute to "online" requests but I must say I have given to Portlight, mainly because of Press and his passion for helping others. Not sure about his "contoversial" political views and don't really care. Everyone has said things that rub some the wrong way. It is a blog for pete's sake and during slow times what else is there to talk about!! I personally miss his comments here.
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Quoting StormChaser81:


Chuck Norris can go invisible if he needs to.

True. lol
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Don't let the convection fool you, 96L is not that well organized today either
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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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