Issued at 400 AM CDT Sun Jul 03 2022


310
WTPZ44 KNHC 030849
TCDEP4

Tropical Storm Bonnie Discussion Number 23
NWS National Hurricane Center Miami FL EP042022
400 AM CDT Sun Jul 03 2022

Geostationary satellite imagery shows a large, persistent convective
cloud mass displaced to the west of Bonnie's low-level center by
some easterly shear. Infrared cloud top temperatures colder than -80
deg C indicate the convection remains vigorous, and it is showing
more signs of curvature in recent imagery after appearing somewhat
amorphous overnight. Unfortunately, no recent microwave or
scatterometer data are available to assess recent structural
changes. A blend of the subjective Dvorak estimates from TAFB and
SAB supports holding the initial intensity at 50 kt.

Environmental conditions appear favorable for Bonnie to strengthen
during the next few days. In the near term, the deep-layer easterly
shear is forecast to slightly diminish while Bonnie traverses warm
SSTs of 28-29 deg C within a moist mid-level environment. The
official NHC forecast calls for Bonnie to become a hurricane by
Monday and continue strengthening during the next 48 h or so. While
not explicitly forecast, the SHIPS guidance suggests some increased
potential for rapid intensification. The latest NHC forecast is
raised slightly higher than the previous one, in line with the IVCN
consensus aid. Increasing northeasterly shear and gradually cooler
SSTs along its forecast track should cause Bonnie's intensity to
level off and gradually decrease by days 4-5.

Bonnie is still moving quickly westward at 275/14 kt. A mid-level
ridge to the north of the cyclone should steer Bonnie westward to
west-northwestward during the next several days, roughly parallel to
the coast of southern Mexico. The track guidance remains in
excellent agreement, and the latest NHC forecast is very similar to
the previous one given the tightly clustered track models. Once
again, this forecast keeps the center of Bonnie far enough offshore
that the tropical-storm-force winds are not forecast to reach the
coast of Central America or Mexico at this time. However, interests
in coastal El Salvador, Guatemala, and southern and southwestern
Mexico should closely monitor updates to Bonnie's forecast track, as
a slight northward adjustment to the track could require tropical
storm watches for portions of this coastline.


KEY MESSAGES:

1. Areas of heavy rainfall are possible across portions of El
Salvador, Guatemala, and southern Mexico during the next couple of
days. This rainfall could cause some instances of flash flooding
and mudslides across the region.

2. Interests along the coasts of Guatemala and southern and
southwestern Mexico should monitor the progress of this system.
While the center of Bonnie is forecast to stay offshore, any
northward adjustment in the track forecast could require the
issuance of a tropical storm watch for part of this area.


FORECAST POSITIONS AND MAX WINDS

INIT 03/0900Z 11.6N 90.6W 50 KT 60 MPH
12H 03/1800Z 12.1N 92.7W 55 KT 65 MPH
24H 04/0600Z 12.8N 95.6W 65 KT 75 MPH
36H 04/1800Z 13.6N 98.5W 75 KT 85 MPH
48H 05/0600Z 14.5N 101.5W 85 KT 100 MPH
60H 05/1800Z 15.2N 104.3W 85 KT 100 MPH
72H 06/0600Z 15.6N 106.7W 80 KT 90 MPH
96H 07/0600Z 16.0N 111.0W 80 KT 90 MPH
120H 08/0600Z 16.5N 115.5W 75 KT 85 MPH

$$
Forecaster Reinhart




Source: Tropical Storm Bonnie Forecast Discussion Number 23