Invest 95L Brushes Louisiana Coastline
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).
Reader Comments
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Thanks for pulling that out, Patrap. Interesting loop for sure.
MARK
21.1N/87.3W
You have the patience of Job.
Thanks Cosmic! I have to admit I've had to bite my tongue a few times over the years.
It should be one circle in the same spot as the last TWO, and I see no reason why the percentage would change from 30%.
Lol....I bet. Welcome :)
Hice hat...welcome...
The east side of the surface trough in the GOM is under 30-40 knots of shear. Maybe more. The strong lower level flow is almost perfectly in opposition with the upper flow.
Transmitted: 6th day of the month at 22:27Z
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: 18
A TD
B TS
C HURRICANE
D STRONG TROPICAL LOW
i think you have posted before. i remember your handle very clearly.
Tropical jet hitting as hard in NOLA as Mobile? Lots of precip here.
e. Nuthin
Yeah any development will be hard to pull off in 48 hours. This system doesn't really have the time to pull itself together. These typhoon-like developments usually require several days to organize. Alex had that kind of time and was able to become a major hurricane. 96L doesn't have that kind of time.
CAT 5 to Houston...
Alex never made it to major status.
A
"Might" is a very strong word.
Current Conditions for the N. Atlantic Ocean, Caribbean Sea, and Gulf of Mexico :
It's almost like "How many fingers am I holding up?"
Hit my hand......
maybe more like,.."Hey, Pull my finger"..
lol
Which one?
I think you are both right. While TOHC has not fully recovered, the 26 degree isotherm is again deep enough to support development of a storm like this one. That's how I read Patrap's post.
I don't care if it did officially or not. 947mb is a major hurricane in my book. The total kinetic energy of the storm far surpassed most Cat 3s that you could pull up. A clear 15nm eye is not something you usually find in a Cat 2 either.
The pressure is a better measure of the overall power of the storm. The surface winds likely were Cat 3-force at landfall but there were no surface stations in the area.
Officially yes it was a Cat 2, but in reality, Alex was a major hurricane by any standard.
Sure does seem like it. lol
Just what we need more hot errr air to fuel the GOM. I happen to think the blow up of lows in the GOM is from all the politicians coming down from Washington for their photo ops. The GOM just couldn't handle it anymore, and exploded in convection to get rid of all that hot air.
Thanks Levi - about what I was at least hoping for.
does anybody else see a little bit of circulation on that wave east of the virgin islands?
Could be, but it had to be several years ago if I did.
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I'll pass...
F-0 in Gentilly.
Minimal Damage..but it did put a Garbage can up on the Telephone Pole wires,dat was cool.,downed some trees.
And Did some roof damage.
NWS Confirmed F-0
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