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Hurricane Bud Discussion Number  12
NWS National Hurricane Center Miami FL       EP032018
900 AM MDT Tue Jun 12 2018

Satellite imagery indicate that Bud peaked in intensity around 0600
UTC, and cloud tops surrounding the well-defined, 20-nmi-diameter
eye have been steadily warming since then. The intensity estimate of
110 kt is based on a blend of TAFB T- and CI-numbers, and a UW-CIMSS
ADT estimate of 110 kt.

Bud has continued to make a trochoidal motion in the general
direction of 320/05 kt during the past 6 hours. Overall, no
significant changes were required to the previous advisory track due
to the latest NHC model guidance remaining very tightly packed. Bud
is forecast to move slowly in a north-northwestward direction around
a large mid-level ridge extending westward across central Mexico for
the next 36 hours or so, followed by a gradual turn toward the north
by late Thursday. On the forecast track, Bud is expected to move
across Baja California Sur as a tropical storm on Thursday. The
official track forecast is essentially just an extension of the
previous advisory track, and lies close to a blend of the various
consensus models.

Although Bud has an impressive upper-level outflow pattern and is
forecast to remain in very low wind shear conditions for the next 48
hours, the cyclone will be moving over cooling SSTs of 26C or less
and ocean heat content values near zero. This should result in
significant cold upwelling beneath the cyclone, which may already be
happening based on erosion of the northern eyewall noted in recent
SSMI/S microwave satellite imagery.  Due to the expected poor
oceanic conditions and upwelling, rapid weakening is forecast to
begin shortly and continue through the remainder of the forecast
period. By 96 hours, Bud is expected to be inland or near the
western coast of mainland Mexico, and likely have dissipated by 120
hours over northwestern Mexico. However, a 120h point has been
priovided for continuity purposes. The official intensity forecast
is close to a blend of the intensity consensus models IVCN, HCCA,
and FSSE.

Based on the forecast track and 34-kt wind radii, a Tropical Storm
Watch could be required for portions of Baja California Sur on the
next advisory package.

FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 18.4N 108.4W  110 KT 125 MPH
 12H  13/0000Z 18.9N 108.8W   95 KT 110 MPH
 24H  13/1200Z 19.6N 109.2W   80 KT  90 MPH
 36H  14/0000Z 20.5N 109.5W   65 KT  75 MPH
 48H  14/1200Z 21.6N 109.9W   55 KT  65 MPH
 72H  15/1200Z 24.4N 110.7W   40 KT  45 MPH
 96H  16/1200Z 28.5N 111.1W   25 KT  30 MPH...INLAND
120H  17/1200Z 32.1N 111.0W   15 KT  15 MPH...POST-TROP/INLAND

$$
Forecaster Stewart

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