Hurricane Leslie

[WxWatcher007]

000
WTNT43 KNHC 021445
TCDAT3

Tropical Depression Thirteen Discussion Number   1
NWS National Hurricane Center Miami FL       AL132024
200 PM CVT Wed Oct 02 2024

The system we have been monitoring several hundred miles to the 
southwest of the southernmost Cabo Verde Islands has become 
gradually better organized this morning with some curved bands 
organizing to the west of the estimated center. Visible satellite 
images show that at least a broad closed circulation has developed. 
Based on the latest subjective Dvorak fixes of T2.5/35-kt from TAFB 
and T1.5/25-kt from SAB, advisories are being initiated on Tropical 
Depression Thirteen, with an initial intensity in between these 
estimates at 30 kt.

The depressions initial motion appears to be slowly due west, at 
270/6 kt. Over the next day or two this motion should continue, 
though some of the track guidance actually shows a south of due west 
motion, partially related to the steering flow and also the 
possibility that the center might try to reform underneath deep 
convective bursts in the southern semicircle. After 48 h, the 
guidance shows TD13 turning west-northwestward and then 
northwestward by the end of the forecast as mid-level ridging 
becomes more eroded on its northwestern side while a large long-wave 
trough becomes established over the Northwest Atlantic. The initial 
NHC track forecast has opted to favor a track close to the consensus 
aid TVCN. Interestingly, both the GFS and ECMWF are on the east side 
of the guidance, while HCCA is on the western side by the end of the 
forecast period. 

Intensity wise, initial strengthening could be on the slower end, as 
the system has to deal with some northwesterly shear related of the 
outflow from the much larger Hurricane Kirk impinging upon the 
system. However, the guidance insists this shear will soon decrease, 
especially after 24-36 h where the upper-level flow seems to split 
off into a cutoff low to the southwest, and a upper-level trough 
that shifts east of the depression, leaving the depression in a more 
favorable upper-level diffluent pattern. After TD13's inner core 
become better defined, the rate of intensification could increase 
after 36 h, and the latest NHC intensity forecast forecasts the 
depression to become a hurricane in 3 days. Additional 
intensification is forecast after that point as long as the cyclone 
tracks far enough away from the cold ocean wake left behind by Kirk. 
This forecast is roughly in the mean of the intensity guidance 
envelope. 


FORECAST POSITIONS AND MAX WINDS

INIT  02/1500Z 10.6N  29.1W   30 KT  35 MPH
 12H  03/0000Z 10.5N  29.8W   35 KT  40 MPH
 24H  03/1200Z 10.2N  30.8W   40 KT  45 MPH
 36H  04/0000Z 10.2N  31.9W   45 KT  50 MPH
 48H  04/1200Z 10.4N  33.3W   55 KT  65 MPH
 60H  05/0000Z 11.0N  34.6W   60 KT  70 MPH
 72H  05/1200Z 11.7N  35.8W   65 KT  75 MPH
 96H  06/1200Z 13.5N  38.1W   75 KT  85 MPH
120H  07/1200Z 16.5N  41.0W   80 KT  90 MPH

$$
Forecaster Papin

 

[WxWatcher007]

 

[WxWatcher007]

Tropical Storm Leslie Discussion Number   3
NWS National Hurricane Center Miami FL       AL132024
1100 PM AST Wed Oct 02 2024

Geostationary satellite and microwave images indicate that the 
system has become better organized with convective bands wrapping 
about two-thirds of the way around the center.  A partial ASCAT pass 
from around 2230 UTC showed winds very close to tropical storm 
force northeast of the center.  Since the system has continued to 
become organized since the ASCAT pass, the initial intensity is 
increased to 35 kt, making the cyclone Tropical Storm Leslie.    
This intensity estimate is also in agreement with a 2.5 Dvorak 
classification from TAFB.

Leslie is moving slowly to the west at about 5 kt.  A continued slow 
westward to west-northwestward motion is expected during the next 2 
to 3 days as Leslie remains steered by a weak mid-level ridge to its 
north.  Beyond that time, a slightly faster motion to the northwest 
is predicted as the storm moves on the western periphery of the 
ridge and approaches a broad trough over the central Atlantic.  The 
models are in fair agreement overall, and the NHC track forecast 
lies near the middle of the guidance envelope.

Leslie is currently in a moderate wind shear environment due to the 
outflow from major Hurricane Kirk to its northwest.  However, the 
shear is expected to lessen while Leslie remains over warm waters 
and in a moist environment.  These condition should support steady 
strengthening during the next few days, and the official intensity 
forecast is a little higher than the previous one.  Beyond a few 
days, Leslie is predicted to move over Kirk's prior track and 
associated cool wake, and into a slightly drier air mass.  These 
conditions could cause the intensity to level off.  The new 
forecast is in best agreement with the latest HCCA guidance.


FORECAST POSITIONS AND MAX WINDS

INIT  03/0300Z 10.4N  30.1W   35 KT  40 MPH
 12H  03/1200Z 10.2N  30.8W   40 KT  45 MPH
 24H  04/0000Z 10.2N  31.9W   50 KT  60 MPH
 36H  04/1200Z 10.4N  33.1W   60 KT  70 MPH
 48H  05/0000Z 10.8N  34.5W   70 KT  80 MPH
 60H  05/1200Z 11.4N  35.8W   80 KT  90 MPH
 72H  06/0000Z 12.2N  37.0W   85 KT 100 MPH
 96H  07/0000Z 14.3N  39.6W   85 KT 100 MPH
120H  08/0000Z 17.0N  42.9W   85 KT 100 MPH

$$
Forecaster Bucci/Cangialosi

[winter_warlock]

Latest Leslie  track.  She's gonna be a major hurricane  soon... definitely  something to watch if she co tinues west

[madwx]

Looks to be forming a core, convection is increasing around 10N 32W

[Windspeed]

Looks like Leslie will be upgraded to a hurricane on the next advisory. AL132024 - Hurricane LESLIE per TAFB best track.

[Windspeed]

[Windspeed]

Leslie: "Hey! Why'd everyone forget about me?!"

[WxWatcher007]

8 minutes ago, Windspeed said:

Leslie: "Hey! Why'd everyone forget about me?!"

GO LESLIE GO

[WxWatcher007]

Hurricane Leslie Discussion Number  31
NWS National Hurricane Center Miami FL       AL132024
1100 PM AST Wed Oct 09 2024

Since the previous advisory, a small eye feature has started 
appearing on geostationary infrared imagery with Leslie, surrounded 
by a ring of very cold (below -70 C) cloud top temperatures. This 
structure is also supported by an earlier SAR-RCM2 pass that showed 
a tight inner core with a radius of maximum wind that had contracted 
from yesterday. 00 UTC subjective Dvorak estimates from TAFB and SAB 
were T5.0/90-kt and T5.5/102-kt, respectively. Objective intensity 
estimates were somewhat lower, between 79-86 kt, and blending the 
data results in a 90 kt intensity this cycle. A Saildrone (SD-1036) 
appears to be near the path of Leslie, and is currently reporting 
sustained tropical-storm-force winds that are quickly increasing 
about 50 n mi northwest of the center. 

As noted previously, another saildrone (SD-1040) indicated that 
sea-surface temperatures near Leslie are warmer than expected, near 
29 C. At the same time, the hurricane is in a very narrow region of 
low vertical wind shear that should persist for another 6-12 h. 
While the interpolated intensity guidance is a bit lower, the raw 
model output of all four of the hurricane-regional models (HAFS-A/B, 
HMON, HWRF) show Leslie briefly becoming a major hurricane in 12 h. 
Because the raw model output from these intensity aids has been 
outperforming the interpolated guidance over the past day, the NHC 
intensity forecast will now show a 100 kt peak tomorrow morning. 
However, this peak is likely to be short-lived, as strong 
upper-level northerly flow, via outflow from Milton and Invest 93L, 
will soon overtake the hurricane, likely leading to rapid weakening. 
Those same hurricane-regional models show Leslie weakening below 
hurricane intensity in 36 h, and that rapid weakening continues to 
be reflected in the latest intensity forecast. While sheared puffs 
of deep convection may continue for a subsequent day or two, 
eventually Leslie is likely to lose the necessary convective 
organization to be classified as a tropical cyclone. The NHC 
forecast continues to show Leslie becoming post-tropical by the end 
of the weekend, though this could occur sooner than forecast given 
the proximity of very dry environmental air and high shear affecting 
the system.

Leslie continues to move northwestward, estimated at 315/7 kt this
evening. The track forecast is more straightforward, with Leslie
rounding the western edge of a subtropical ridge to its east,
resulting in a gradual turn northward and then northeastward over
the forecast period. With that said, there has been a notable
westward and poleward shift in the guidance this cycle, and the NHC
track forecast was moved in that direction, but not as far as the
latest TVCN and HCCA consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT  10/0300Z 22.6N  49.3W   90 KT 105 MPH
 12H  10/1200Z 23.3N  49.9W  100 KT 115 MPH
 24H  11/0000Z 24.4N  50.4W   80 KT  90 MPH
 36H  11/1200Z 26.0N  50.1W   55 KT  65 MPH
 48H  12/0000Z 28.4N  48.4W   45 KT  50 MPH
 60H  12/1200Z 30.7N  45.5W   45 KT  50 MPH
 72H  13/0000Z 33.0N  41.6W   45 KT  50 MPH
 96H  14/0000Z 36.0N  31.0W   40 KT  45 MPH...POST-TROPICAL
120H  15/0000Z 37.1N  21.9W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Papin

[NJwx85]

Naked swirl alert.

[WxWatcher007]

So close lol