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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check out buoy 42001 on the NOAA site



(first time posting, but have lurked since 2005)
Member Since: Posts: Comments:
1868. Patrap
Quoting msgambler:
Your gonna upset alot of folks makin' statements lik dat.


So whats new..?

pfffth
Member Since: July 3, 2005 Posts: 421 Comments: 127550
Ther is some circulation afterall...go figure.

96L
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1866. Patrap
Quoting scott39:
what do you expect out of 96L in the short term Pat?



Its gonna take another 24 to shake out seems.

The NHC will follow the Southern one till its apparent tha Mid Gulf one is dominate.

They dont trend well to er,..the Obvious sometimes.
Member Since: July 3, 2005 Posts: 421 Comments: 127550
Quoting Patrap:


The Yucatan Vortex is Toast..the energy is now focusing mid GOM
Your gonna upset alot of folks makin' statements lik dat.
Member Since: February 27, 2010 Posts: 0 Comments: 1125
reposting

wow very interisting a trough and a tropical wave together



and our African AOI nice look at wind barbs

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Hey all.


EA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
347 PM CDT TUE JUL 6 2010

.DISCUSSION...
MAIN REGIONAL ITEMS OF NOTE INCLUDE THE UPPER LOW EAST OF THE
LOWER TX COAST...THE SURFACE LOW ON THE SABINE JUST SOUTH OF
KSHV...AN UPPER RIDGE OVER N TX AND THE BIG BEND...AND THE
TROPICAL WAVE OVER THE SE GULF AND W CARIBBEAN.

THE MODELS AGREE IN KEEPING THE SURFACE LOW NORTH OF THE FORECAST
AREA TONIGHT. THE UPPER RIDGE REMAINS FAIRLY STATIONARY THROUGH
FRIDAY. THE UPPER LOW WILL DRIFT INTO THE LOWER RIO GRANDE TONIGHT
AND WEDNESDAY AND WILL HELP SET UP A DEEP EASTERLY FLOW. THIS WILL
HELP STEER THE MOISTURE FROM THE TROPICAL WAVE OVER SE TX SOMETIME
ON WEDNESDAY. BOTH THE NAM AND GFS SET UP A COASTAL TROUGH BY
WEDNESDAY NIGHT. WITH THE ARRIVAL OF PW/S BETWEEN 2.5 AND 2.8
INCHES...THE HEAVIEST RAINFALL POTENTIAL LOOKS TO BE FROM
WEDNESDAY NIGHT INTO THURSDAY. AS THERE IS STILL SOME UNCERTAINTY
ON THE TIMING...DECIDED TO WAIT UNTIL THE MIDNIGHT SHIFT BEFORE
ISSUING A WATCH. WILL INSERT HEAVY RAINFALL POSSIBLE FOR LOCATIONS
HAVING LIKELY AND ABOVE POPS WEDNESDAY THROUGH THURSDAY.

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Quoting Patrap:


The Yucatan Vortex is Toast..the energy is now focusing mid GOM
Nope. Just look at the latest vorticity graphs and you'll see continuing weakening of the low in the GOM.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
1860. Patrap
Hurricane Alex GOM Wake is Long gone..

The TCHP is back..and warmer.

Member Since: July 3, 2005 Posts: 421 Comments: 127550
1859. scott39
Quoting Patrap:


The Yucatan Vortex is Toast..the energy is now focusing mid GOM
what do you expect out of 96L in the short term Pat?
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Quoting Patrap:


The Yucatan Vortex is Toast..the energy is now focusing mid GOM


Not at all. Vorticity maps show a continued decrease in vorticity in the northern part of the trof and an increase in the vort over the Yucatan.
Member Since: Posts: Comments:
1857. Levi32
Quoting scott39:
Do you think it has time before it hits land?


It has a chance but not too great of one. The mid-level low over the Yucatan, if it can work down to the surface, would be the one to develop, but it will be moving over the cold-water wake of Alex which will limit development.
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1856. Patrap
Quoting scott39:
Do you think it has time before it hits land?


The Yucatan Vortex is Toast..the energy is now focusing mid GOM
Member Since: July 3, 2005 Posts: 421 Comments: 127550
Quoting MississippiWx:


The mid-level low over the Yucatan is the more dominant feature and unless something changes, it will win.
Exactly.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
1854. scott39
Quoting Levi32:
96L needs to kick the northern center out into Texas/Louisiana to give the southern center any chance. Right now the system is fighting with itself for energy.

Strung-out vorticity:

Do you think it has time before it hits land?
Member Since: Posts: Comments:
1853. Patrap
Product: NOAA Temp Drop (Dropsonde) Message (UZNT13 KWBC)
Transmitted: 6th day of the month at 21:53Z
Aircraft: Gulfstream IV-SP (G-IV) (Reg. Num. N49RF)
Mission: Non-Tasked Mission, possibly not tropical (flight in the North Atlantic basin)
Mission Identifier: Al96 (Probably storm name and mission number)



Observation Number: 15

Member Since: July 3, 2005 Posts: 421 Comments: 127550
Quoting Patrap:


U betcha


The mid-level low over the Yucatan is the more dominant feature and unless something changes, it will win.
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1849. scott39
Quoting palmpt:


I hope this season does not continue like this...A lot of activity... and weird activity. Alex was the invest from hell... never could seem to get its act together. We were all worn out by the time it formed. And then 95L... and then this crazy 96L. Who the heck knows what is coming next? No matter where this goes, the Deepwater Horizon site can't get a break. And this is June! Good Lord. I know some folks here that better pace themselves. These systems are going to drive some folks crazy.
Some folks on here need to take a break from here, if its going to drive them KooKooKoo!
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1848. Patrap
Quoting washingaway:


To many people looking at the floater and missing the big picture.


U betcha
Member Since: July 3, 2005 Posts: 421 Comments: 127550
Quoting Levi32:


Lol. Well, it wasn't as obvious last night, but it has been very apparent on visible satellite imagery since daybreak, at least to me. It was moving through the Yucatan Channel yesterday. It's a nice little trough really...


To many people looking at the floater and missing the big picture.
Member Since: Posts: Comments:
1846. Patrap
Product: NOAA Temp Drop (Dropsonde) Message (UZNT13 KWBC)

Transmitted: 6th day of the month at 21:53Z

Aircraft: Gulfstream IV-SP (G-IV) (Reg. Num. N49RF)

Mission: Non-Tasked Mission, possibly not tropical (flight in the North Atlantic basin)

Mission Identifier: Al96 (Probably storm name and mission number)
Observation Number: 15

Part A...
Part A...

Date: Near the closest hour of 22Z on the 6th day of the month
Highest Mandatory Level For Which Wind Was Reported: 150mb
Coordinates: 17.6N 85.5W (View map)
Location: 177 miles (285 km) to the E (88°) from Belize City, Belize.
Marsden Square: 045 (About)
Member Since: July 3, 2005 Posts: 421 Comments: 127550
Quoting JLPR2:


Nice, I had no idea recon was flying out, thanks for the info :)




AOI
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Quoting btwntx08:
1831 please delete that is too long of a post
Sorry i wanted to copy recons data but i copied the wrong file anyway i will let some one else copy recon as it approaches the invest
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1843. Levi32
96L needs to kick the northern center out into Texas/Louisiana to give the southern center any chance. Right now the system is fighting with itself for energy.

Strung-out vorticity:

Member Since: Posts: Comments:
1842. palmpt
Quoting Patrap:


The sky Looks too August Like.

Itsa Creepy GR.


I hope this season does not continue like this...A lot of activity... and weird activity. Alex was the invest from hell... never could seem to get its act together. We were all worn out by the time it formed. And then 95L... and then this crazy 96L. Who the heck knows what is coming next? No matter where this goes, the Deepwater Horizon site can't get a break. And this is early July! Good Lord. I know some folks here that better pace themselves. These systems are going to drive some folks crazy.
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1841. JLPR2
Quoting belizeit:
Recon Is almost to 96 L so we soon should be getting some d




Nice, I had no idea recon was flying out, thanks for the info :)
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1840. hydrus
Quoting centex:
The spin on 96L has improved today. I think NHC may up it's chances tonight.
Link Looks like the mid-level spin over the Yucatan is heading west. At least for the moment.
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OMG...Wow! Look in the East Atlantic and the wave coming off the coast of Africa. You know what that means! Troubles for you know who! Better watch out!
Member Since: September 10, 2007 Posts: 0 Comments: 10976
1838. scott39
The energy really is spread from N to S on 96L. If 96l goes more WNW or W, the dry air will really hinder developement. IMO
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1835. Levi32
Quoting beell:


Never saw it that far north yesterday-or even this morning. Oh, well-I still got my day job.


Lol. Well, it wasn't as obvious last night, but it has been very apparent on visible satellite imagery since daybreak, at least to me. It was moving through the Yucatan Channel yesterday. It's a nice little trough really...
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1834. centex
The spin on 96L has improved today. I think NHC may up it's chances tonight.
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1833. Patrap




Member Since: July 3, 2005 Posts: 421 Comments: 127550
Quoting GetReal:


Now that 95L is history, and out of the way, the winds here in the NOLA area have switched back around to a easterly direction, in response to the new surface low in the central GOM. The winds are gusty, with the usual low flying cloud deck that is common with tropical systems.

IMO the surface low over the central GOM may very well bewcome the dominate feature, as it has recently begun to steal some of the energy to the south, over the Yucatan...


Interesting.
It could also inhibit the development of both lows... at least into hurricanes.

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Recon Is almost to 96 L so we soon should be getting some d


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Some of you guys are waaaaay too sensitive. The reason I posted that way was so that I didn't start any rumors. I didn't want to post, "Hey, Levi! Don't you think that's a surface circulation that has formed?"
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Quoting washingaway:


Maybe they will mate, and we will have Bonnie


LOL!!!
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1827. Patrap
worse than anything we've seen since Camille...

Me tinks we saw dat in 05 easily
Member Since: July 3, 2005 Posts: 421 Comments: 127550
1825. beell
Quoting Levi32:


What surface trough? The one in the central gulf has been there forever.


Never saw it that far north yesterday-or even this morning. Oh, well-I still got my day job.
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Quoting msgambler:
Are you saying what I think your saying?


I don't even know what I am saying half the time... so the chances of you knowing.. are pretty slim :)
Member Since: Posts: Comments:
Quoting GetReal:


Now that 95L is history, and out of the way, the winds here in the NOLA area have switched back around to a easterly direction, in response to the new surface low in the central GOM. The winds are gusty, with the usual low flying cloud deck that is common with tropical systems.

IMO the surface low over the central GOM may very well bewcome the dominate feature, as it has recently begun to steal some of the energy to the south, over the Yucatan...


Maybe they will mate, and we will have Bonnie
Member Since: Posts: Comments:
Oh my. That could be worse than anything we've seen since Camille...

(j/k, nothing amiss. Just yankin a chain...)
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1821. Patrap
Sounds like someone or some folks are confused..


Member Since: July 3, 2005 Posts: 421 Comments: 127550
1820. Levi32
Quoting beell:
Wow! Where did the big-a surface trough come from? Just when you think you know everything!


What surface trough? The one in the central gulf has been there forever.
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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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