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TROPICAL STORM CELIA DISCUSSION NUMBER 34
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016
800 PM PDT THU JUL 14 2016
Deep convection within Celia has been steadily deteriorating with
only a few patches of moderately cold cloud tops existing in the
northern semicircle. Consistent with this downward trend, the SAB
and TAFB subjective Dvorak classifications have dropped to current
intensity numbers of 2.0 and 2.5, respectively, suggesting an
intensity of 30-35 kt. However, a recent ASCAT-A scatterometer pass
indicated that peak winds near 50 kt were still occurring. Assuming
some weakening since that time, the initial intensity is assessed at
45 kt.
Despite the resilience of the vortex today, Celia should soon
succumb to the effects of cool 24-25 deg C SSTs, a stable
atmosphere, and convergent upper-level flow. Thus it is
anticipated the the system will lose its deep convection and become
a post-tropical cyclone on Friday and degenerate to a remnant low by
Saturday. Due in part to the strong synoptic-scale pressure
gradient to Celia's north, the system should be able to maintain
peak winds of about 30 kt for the next few days. The NHC intensity
forecast is based upon the IVCN consensus, in which the
statistical models dissipate Celia more quickly, while the
dynamical models hold on to Celia perhaps too robustly.
Celia is moving toward the west-northwest at about 12 kt due to the
steering influence of a strong subtropical ridge to its northeast.
As the cyclone decays, it should be carried along in the low-level
easterly trade wind flow toward the west at about the same forward
speed. The NHC track forecast is based upon the TVCN consensus,
which shows a tight packing of its individual members. On the
forecast track, Celia is expected to move into the Central Pacific
basin tomorrow morning.
The scatterometer pass indicated that the tropical-storm-force wind
radii were somewhat larger than earlier analyzed. Consistent with a
larger-sized circulation, an altimeter pass showed that the extent
of 12-ft seas was also substantially larger than indicated in the
last advisory.
FORECAST POSITIONS AND MAX WINDS
INIT 15/0300Z 21.8N 139.1W 45 KT 50 MPH
12H 15/1200Z 22.2N 140.9W 40 KT 45 MPH
24H 16/0000Z 22.3N 143.3W 35 KT 40 MPH...POST-TROPICAL
36H 16/1200Z 22.4N 145.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 17/0000Z 22.8N 148.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 18/0000Z 23.8N 152.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 19/0000Z 24.5N 157.3W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 20/0000Z 25.4N 162.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
$$
Forecaster Landsea
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