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Tropical Storm Carlos Discussion Number 4
NWS National Hurricane Center Miami FL EP032021
800 AM PDT Sun Jun 13 2021
Deep convection has persisted over the center of Carlos throughout
the night and a new convective burst with cloud tops of -60 to -70
degrees C is occuring over the estimated center location. A blend
of the latest Dvorak intensity estimates from TAFB and SAB support
increasing the initial intensity to 45 kt. This seems reasonable,
as an earlier ASCAT-B overpass had several vectors of 40-41 kt,
and the vortex likely has spun up further due to the ongoing deep
convection.
Carlos continues to move west at around 7 kt, steered by a
mid-level ridge to the north. This ridge is forecast to become
oriented northeast to southwest later today and prevail over the
next couple days which should cause the cyclone to move slowly
west-southwestward. After 48 h the models diverge significantly in
their track solutions, with the GFS and ECMWF turning the system
abruptly northward, while most of the other guidance has a more
westward then west-northwestward motion beyond 72 h. There is a mid-
to upper-level low currently located west of Mexico that the models
are handling differently. The easternmost track solutions for Carlos
weaken this feature more quickly and replace it with a ridge to the
east of Carlos, while the western solutions keep the feature around,
delaying the more poleward motion of the cyclone. The latest NHC
track forecast is near the previous one through 48 h, but is shifted
west thereafter. Still, the NHC forecast track is well east of the
consensus after 48 h. Needless to say the track forecast confidence
beyond day 2 is low.
Northerly shear of 10-15 kt and the proximity to dry and stable
mid-level air to its north should cause periodic weakening of the
storm's deep convection, which would prevent any further
strengthening, and Carlos is expected to hold its current
intensity for the next couple of days. Thereafter, regardless of
the western or eastern track model solutions, Carlos is expected to
encounter an even drier and more stable airmass and cooler sea
surface temperatures. This should cause a weakening trend to begin
by mid-week. The latest NHC intensity forecast is little changed
from the previous one, and is close to the multi-model consensus.
FORECAST POSITIONS AND MAX WINDS
INIT 13/1500Z 11.8N 126.0W 45 KT 50 MPH
12H 14/0000Z 11.6N 126.7W 45 KT 50 MPH
24H 14/1200Z 11.1N 127.5W 45 KT 50 MPH
36H 15/0000Z 10.7N 128.0W 45 KT 50 MPH
48H 15/1200Z 10.4N 128.5W 45 KT 50 MPH
60H 16/0000Z 10.4N 129.0W 40 KT 45 MPH
72H 16/1200Z 11.0N 129.4W 35 KT 40 MPH
96H 17/1200Z 12.8N 129.6W 30 KT 35 MPH
120H 18/1200Z 15.2N 129.4W 30 KT 35 MPH
$$
Forecaster Latto
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