Eastern Pacific Basin Tropical Cyclones

Tropical Storm Bonnie Forecast Discussion


668 
WTPZ44 KNHC 030323
TCDEP4

Tropical Storm Bonnie Discussion Number  22...Retransmitted
NWS National Hurricane Center Miami FL       EP042022
1000 PM CDT Sat Jul 02 2022

This evening's conventional satellite presentation consists of an 
impressive deep convective curved band with -83C cloud tops 
encompassing the west side of the cyclone.  Earlier SSM/S and AMSR2 
microwave passes revealed inner core ring development that was about 
60 percent closed in the northern quadrants.  There appears to be a 
slight vertical tilt toward the west, more than likely due to the 
period it spent moving across Nicaragua.  The initial intensity is 
raised to 50 kt and is based on a compromise of the various 
subjective and objective satellite intensity estimates. 

The shear is low, the water is warm, and the atmosphere is moist, 
all contributing to further strengthening during the next few days,
and Bonnie is expected to become a hurricane in 24 hours.  Around
mid-period, the global models and the GFS/ECMWF SHIPS intensity
guidance show modest northeasterly shear impinging on Bonnie's
outflow pattern.  As a result, the official intensity forecast
calls for a slight weakening beyond day 3.

Bonnie's initial motion is estimated to be due west or 270/15 kt.
A mid-tropospheric ridge stretching from the northern Gulf of
Mexico to the Baja California peninsula should cause the cyclone to
turn west-northwestward Sunday and continue in this heading through 
the remainder of the forecast period.  The global and regional 
model track guidance remains in agreement, and these tightly 
clustered aids, as well as the NHC forecast, takes Bonnie 
approximately parallel to the coasts and keeps the 
tropical-storm-force winds offshore of the southern coast of 
Central America and Mexico. However, interests in coastal El 
Salvador, Guatemala, and southwestern Mexico should closely monitor 
Bonnie's forecast track for the next few days 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 expected across portions of
Nicaragua, Costa Rica and the southern portion of El Salvador
through tonight.  This rainfall may cause some instances of flash
flooding and mudslides across the region.

2. Interests along the coasts of Honduras, El Salvador, Guatemala,
and southeastern 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  03/0300Z 11.3N  89.5W   50 KT  60 MPH
 12H  03/1200Z 11.6N  91.4W   55 KT  65 MPH
 24H  04/0000Z 12.4N  94.2W   65 KT  75 MPH
 36H  04/1200Z 13.2N  97.1W   70 KT  80 MPH
 48H  05/0000Z 14.1N 100.2W   75 KT  85 MPH
 60H  05/1200Z 15.1N 103.2W   80 KT  90 MPH
 72H  06/0000Z 15.6N 105.8W   75 KT  85 MPH
 96H  07/0000Z 15.9N 110.2W   70 KT  80 MPH
120H  08/0000Z 16.3N 114.3W   70 KT  80 MPH

$$
Forecaster Roberts




Source link