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Hurricane Bonnie Discussion Number 39
NWS National Hurricane Center Miami FL EP042022
300 AM MDT Thu Jul 07 2022
The convection associated with Bonnie is gradually losing
organization as the cyclone continues to feel the effects of shear
and moves over cooler waters. However, while there has been no
distinguishable eye feature for several hours in IR imagery, a
just-received GMI 37 GHz microwave overpass shows a well-defined
low-level eye under the convective overcast. Objective and
subjective satellite intensity estimates range from 60-90 kt, which
is a greater than normal spread. However, the estimates are
trending downward, and based on this the initial intensity is
decreased to an uncertain 80 kt. The 34-kt wind radii have been
reduced based on recent scatterometer data.
Bonnie is moving over progressively cooler water and into a dry
air mass. This combination should cause steady to rapid weakening.
Current expectations are that Bonnie will stop producing convection
between 48-60 h and become a post-tropical cyclone. The system is
expected to decay to a remnant low by 72 h, and the dynamical
models are in good agreement that it will weaken to a trough by 96
h. The new intensity forecast follows the overall trend of the
intensity guidance and has only minor adjustments from the previous
forecast.
The initial motion is 290/12 kt as Bonnie is steered by a mid-level
ridge to its north. There is no change to the track forecast
philosophy and little change to the forecast from the previous
advisory. The ridge is predicted to steer Bonnie west-northwestward
for the next couple of days until its circulation weakens and the
resulting shallower vortex follows the faster, westward trade wind
flow. The new track forecast lies in the middle of the tightly
clustered track guidance.
FORECAST POSITIONS AND MAX WINDS
INIT 07/0900Z 17.1N 112.5W 80 KT 90 MPH
12H 07/1800Z 17.7N 114.3W 75 KT 85 MPH
24H 08/0600Z 18.4N 117.4W 65 KT 75 MPH
36H 08/1800Z 19.0N 120.9W 55 KT 65 MPH
48H 09/0600Z 19.6N 124.4W 45 KT 50 MPH
60H 09/1800Z 19.9N 128.2W 35 KT 40 MPH...POST-TROPICAL
72H 10/0600Z 20.1N 131.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 11/0600Z...DISSIPATED
$$
Forecaster Beven
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