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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Good point.
They are in the tub ready to hunker down for any storm! No other place to go in my 1926 house having no rooms without windows!
He's one of the best of us
G'nite Aussie. Make sure to check under the bed for Chuck Norris....
Spent a lot of time talking to him, have you? While I'll admit my post was over-simplification, his reasoning had a great deal do with that as it did his feeling that his activities here were harming Portlight's cause. My argument to him was that he, to a large extent, IS Portlight and the people he felt he was alientaing were not the people that gave freely of themselves to that sort of organization anyway...
It has felt like a Gulf season since at least May, possibly April. The early spring weather actually reminded me of both 2005 and 2008.
96L has always seemed to have two areas of spin. One at the low levels that runs ahead or at the North end of the system with little convection that currently would seem to be well into the Gulf now. The other further South currently over the Yucatan that doesn't seem to be at the low level but has most of the convection with it. It does seem possible that the North one could get pulled up by 95L while the South one follows the WNW track. Keep in mind that this is all babble by a non-met.
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.
Chuck Norris can go invisible if he needs to.
Stay at 30%...convection fading some over the Yucatan.
Structure-wise though, looking very impressive.
True. lol
yeah, no upgrade over the Yucatan....maybe not over the GOM as well...
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.
50%
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.
....if you see him, you're in trouble.....if you don't, your dead......LOL
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
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".
Well said...
lol, Got to watch the fist that comes from his chin, its deadly.
It needs to move over water as well if it wants to intensify.
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.
Yep, we noticed. LOL.
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.
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