INVEST 91L : East of Lesser Antilles : Gone from NRL

[Gustywind]

Strong westerly shear 20 kts
persisting...
http://cimss.ssec.wisc.edu/tropic/real- ... g8shr.html
Always strong....
http://cimss.ssec.wisc.edu/tropic/real- ... g8sht.html

[MiamiensisWx]

Latest RAMSDIS IR image:



You can clearly detect the exposed LLC near 16N and 52W. If shear was less inhibitive, 91L would have probably been a tropical depression. Interestingly, the recent QuikSCAT pass indicates a partially open circulation with no W wind barbs. Overall, it's a classical "cusp" situation under high shear. This one will clearly experience a painful death, so the current convective increase is probably partially tied to UL divergence.

[Matt-hurricanewatcher]

A buoy just south of the LLC has turned southwestward. Meaning its a LLC. Also convection has pushed over it...I say likely depression and maybe a tropical storm if current trends keep up. Just think what it would do if it was not for the tutt.

[Matt-hurricanewatcher]

07/0645 UTC 15.3N 52.7W T1.5/1.5 91L

[americanrebel]

That should make it a TD then.

[Thunder44]

That should make it a TD then.

It's not going to be upgraded to a TD based on those numbers alone. We need to see if a closed surface circulation exists first.

[Matt-hurricanewatcher]

That should make it a TD then.

It's not going to be upgraded to a TD based on those numbers alone. We need to see if a closed surface circulation exists first.

With the westly winds on the buoy south of the system,. That answers at least most of that question. How strong it is, I would say 30-35 knots.

[Thunder44]

With the westly winds on the buoy south of the system,. That answers at least most of that question. How strong it is, I would say 30-35 knots.

Yeah, I see that now. But that would put most of convection east of the center.

http://ndbc.noaa.gov/station_page.php?station=41040

[Thunder44]

From the 5:30am TWO:

AN AREA OF LOW PRESSURE IS CENTERED ABOUT 500 MILES EAST OF THE
LESSER ANTILLES. UPPER-LEVEL WINDS ARE NOT PARTICULARLY FAVORABLE
FOR SIGNIFICANT DEVELOPMENT. THIS LOW IS EXPECTED TO MOVE SLOWLY
NORTHWESTWARD DURING THE NEXT DAY OR SO.

FORECASTER BLAKE

[Thunder44]

With the westly winds on the buoy south of the system,. That answers at least most of that question. How strong it is, I would say 30-35 knots.

Yeah, I see that now. But that would put most of convection east of the center.

http://ndbc.noaa.gov/station_page.php?station=41040

I'm questioning again if this system really has a closed LLC. The past few hours there west to WSW winds but they were light, no more than about 6kts, than suddenly switched to the NNW and then stronger out the East, between 8:00 and 8:50GMT. Highest one-minute sustained wind reported at 8:27 GMT was at 20.2kts. Same time pressure bottomed out at 6:50 GMT at 29.80" or 1009mb and started to rise again to 29.82". Looks like low passed right over the buoy, when the winds were lighter. It might be more of cusp, that MiamiensisWx, was talking about with last night's QS pass. There should be another pass this later this morning.

Edit: Since I posted the buoy 41040 is now reporting winds out the SE, with one-minute sustained max of 21kts in the past hour. Also the QS pass is in but it looks like it will miss this system:

http://manati.orbit.nesdis.noaa.gov/dat ... MBas26.png

[cycloneye]

8 AM TWD:

TROPICAL WAVE IS ALONG 52W/53W S OF 18N MOVING W 10 KT. A 1008
MB LOW IS LOCATED ALONG THE WAVE AXIS NEAR 16N. BUOY 41040 HAS
BEEN VERY HELPFUL IN ANALYZING THIS LOW. IR IMAGERY SHOWS A BALL
OF CONVECTION THAT HAS BEEN MAINTAINED THROUGHOUT THE OVERNIGHT
HOURS. HOWEVER...ALL OF THIS CONVECTION IS SITUATED TO THE E/SE
OF AN EXPOSED LOW-LEVEL CIRCULATION CENTER. THIS LOW PRES SYSTEM
IS OBVIOUSLY FEELING THE EFFECTS OF WLY SHEAR WHICH IS HAMPERING
FURTHER ORGANIZATION.


Thunder44,the center is exposed to the NW of convection.

[Gustywind]

Westerly Shear 20kts
http://cimss.ssec.wisc.edu/tropic/real- ... g8shr.html

http://cimss.ssec.wisc.edu/tropic/real- ... g8sht.html
No more changes...whereas a a small pocket of decreasing winds can be observed in vicinity of Invest 91L

Correct me if wrong but the system is maybe moving slighlty west south west for my untrained eyes or my eyes are deceiving me , did someone noticed that or can explain me...is the main convection drifting wsw and the LLC exposed moving w or nw... on this loop
http://www.ssd.noaa.gov/goes/east/catl/loop-wv.html

[Gustywind]

07/1145 UTC 16.6N 53.7W T1.0/1.5 91L -- Atlantic Ocean
Latest from SSD position intensity....

[curtadams]

Looks like it was beheaded by mid-shear last night. Last night the convection was tracking the LLC but "downshear" of it. Now it's south of the convection even though the relative shear is to the east. It's also having trouble with dry air in some layer based on the line between convection to the E and none to the W. Not at the higher levels; the WV is unremarkable.

[Gustywind]

Latest fron NRL site: 15.1 N 52.2w 25 kts 1008 hpa 1215 UTC
http://www.nrlmry.navy.mil/tc-bin/tc_ho ... k_vis/dmsp

[Fego]

LLC going WNW, meantime the convection is moving WSW.

[cycloneye]

That is decouple.LLC going one way and the MLC going in another direction.

[Gustywind]

LLC going WNW, meantime the convection is moving WSW.

Ok tkanks Fego ....so my eyes are not so bad ...meantime . Whereas tenacious low pressure figthing in against his strong shear environnement....something to watch as usual

[Gustywind]

http://www.meteo.gp/donnees/satellite/TAG/Tagant.jpg latest meteo-france
10am

[cycloneye]

11:30 AM TWO:

AN AREA OF LOW PRESSURE CENTERED ABOUT 500 MILES EAST OF THE
LESSER ANTILLES REMAINS POORLY ORGANIZED. UPPER-LEVEL WINDS ARE
UNFAVORABLE FOR DEVELOPMENT OF THIS SYSTEM AS IT MOVES
NORTHWESTWARD AT ABOUT 10 MPH DURING THE NEXT DAY OR SO.