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Tropical Storm Carlotta Discussion Number 5
NWS National Hurricane Center Miami FL EP032024
800 AM MST Thu Aug 01 2024
After intensifying over the past 12 to 18 hours, Carlotta is taking
a brief pause as the inner-core becomes better established, though
the system is still quite healthy looking on satellite imagery with
plenty of curved bands around a formative central dense overcast
(CDO). A blend of the latest subjective Dvorak intensity estimates
still support an intensity of 50-kt this advisory, which is also
roughly in the middle of objective intensity guidance.
Carlotta continues to move west-northwestward at 295/10-kt. This
motion is caused by a prominent deep-layer ridge located over the
southwestern United States, and Carlotta may turn more back westward
over the next few days as this ridge continues to strengthen.
However by day 3 and beyond, the tropical cyclone will begin to
feel a weakness to the north, which will likely result in a gradual
slowdown in its forward motion and another gentle shift more
poleward in the track. The latest track guidance is ever so slightly
further north and faster compared to the previous cycle. Thus, the
NHC track forecast has been shifted a bit in that direction,
roughly in between the prior track forecast, and the reliable
consensus aids TVCE and HCCA.
Environmental conditions still appear quite favorable for
intensification, with warm 28-29 C sea-surface temperatures (SSTs),
and low to moderate shear between 10-15 kt out of the northwest. The
rate of intensification may be determined more by how Carlotta's
inner-core evolves, and there have not been any recent microwave
images to diagnose the current structure. The SHIPS rapid
intensification index is a little lower than last night, though this
could also be in response to the temporary pause in the
intensification. However the last few GOES-18 images suggest the CDO
is becoming better established though an eye has yet to fully appear
on first-light visible imagery. Even though the intensity guidance
has shifted a little lower than last night, I have elected to keep
the same intensification rate in the NHC forecast from the last
cycle over the next 24 hours. This forecast is in better agreement
with the regional-hurricane models HAFS-A/B versus the lower
consensus aids that have been influenced by the lower SHIPS and LGEM
guidance. After 48-60 hours, SSTs begin to markedly decrease along
the forecast track, dropping under 26 C in 96 hours. Thus, the NHC
intensity forecast shows gradual weakening between days 3 to 5.
FORECAST POSITIONS AND MAX WINDS
INIT 01/1500Z 17.2N 111.0W 50 KT 60 MPH
12H 02/0000Z 17.9N 112.6W 65 KT 75 MPH
24H 02/1200Z 18.2N 114.8W 75 KT 85 MPH
36H 03/0000Z 18.3N 117.0W 85 KT 100 MPH
48H 03/1200Z 18.4N 119.2W 90 KT 105 MPH
60H 04/0000Z 18.6N 121.0W 85 KT 100 MPH
72H 04/1200Z 19.0N 122.7W 80 KT 90 MPH
96H 05/1200Z 19.5N 125.5W 65 KT 75 MPH
120H 06/1200Z 20.0N 128.0W 55 KT 65 MPH
$$
Forecaster Papin
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