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Tropical Storm Iselle Discussion Number 14
NWS National Hurricane Center Miami FL EP142020
300 PM MDT Sat Aug 29 2020
Iselle has become less organized during the past several hours, as
the area of convection southwest of the center is now smaller and
farther from the center than previously. This is likely due to the
combined effects of continued easterly shear and decreasing sea
surface temperatures under the storm. A recent ASCAT overpass
shows that maximum sustained winds remain near 40 kt, but the
tropical-storm-force winds are now occurring only over the
southeastern quadrant.
The initial motion is north-northeastward or 025/6 kt. Iselle
should turn toward the north during the next several hours as it
is steered by a mid-level ridge to the east. The northward motion
should continue for another day or so, followed by a turn toward
the northwest as Iselle becomes a weak and shallow system. The new
forecast track again has minor adjustment from the previous track
based mainly on the initial position and motion.
The shear and cooler water along the forecast track should cause
Iselle to steadily weaken, and the new forecast track has no
changes from the previous forecast. The forecast, which calls for
the cyclone to weaken to a depression by 24 h, to degenerate to a
remnant low by 36 h, and to weaken to a trough by 72 h, again lies
at the upper edge of the intensity guidance.
FORECAST POSITIONS AND MAX WINDS
INIT 29/2100Z 21.0N 114.5W 40 KT 45 MPH
12H 30/0600Z 22.1N 114.5W 35 KT 40 MPH
24H 30/1800Z 23.4N 114.8W 30 KT 35 MPH
36H 31/0600Z 24.2N 115.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 31/1800Z 24.8N 115.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
60H 01/0600Z 25.4N 116.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 01/1800Z...DISSIPATED
$$
Forecaster Beven
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