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Tropical Storm Adrian Discussion Number   1
NWS National Hurricane Center Miami FL       EP012023
300 PM MDT Tue Jun 27 2023
 
The low pressure system located a few hundred miles off the
southwestern coast of Mexico has quickly become better organized
since last night, in terms of both its center definition and
convective structure.  ASCAT passes received a few hours ago
indicated that the low has a well-defined center, and the system is
already producing winds of around 40 kt.  Based on this, advisories
are being initiated on Adrian, the first tropical cyclone (and
named storm) of the 2023 eastern Pacific season.
 
With Adrian's center only recently forming, the initial motion is
an uncertain 280/13 kt.  A weakening subtropical ridge stretching 
across northern Mexico over the eastern Pacific is expected to steer 
Adrian generally westward during the next 3 days, but with its 
forward speed gradually decreasing during that time.  The 
model guidance is in fairly good agreement during this period. 
There is significantly more uncertainty after day 3, and Adrian is 
expected to slow down further and turn toward the northwest and 
north due to (1) a developing mid- to upper-level low west of the 
Baja California peninsula and (2) possible interaction with another 
weather system to its east closer to the coast of Mexico.  The NHC 
track forecast is close to the HCCA and TVCE consensus aids on days 
4 and 5.

Relatively low wind shear and warm sea surface temperatures of 28 
to 29 degrees Celsius are likely to foster strengthening.  In fact, 
some of the rapid intensification (RI) indices suggest that RI could 
occur, and the NHC forecast shows fast strengthening during the 
next couple of days.  In general, the official intensity forecast 
is above the intensities of the hurricane regional models since 
they don't seem to be initializing the storm's structure very well. 
Model guidance suggests that moderate to strong easterly shear 
could develop over Adrian in about 3 days, with the storm also 
reaching cooler waters by around days 4 and 5.  Therefore, weakening 
is indicated in the forecast toward the end of the forecast period.
 
Adrian's genesis marks the second-latest formation of the first 
named storm during the eastern Pacific hurricane season, after 
Tropical Storm Agatha of 2016 which formed on July 2.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/2100Z 15.3N 106.0W   40 KT  45 MPH
 12H  28/0600Z 15.4N 107.4W   55 KT  65 MPH
 24H  28/1800Z 15.4N 108.8W   65 KT  75 MPH
 36H  29/0600Z 15.5N 110.3W   75 KT  85 MPH
 48H  29/1800Z 15.6N 111.6W   75 KT  85 MPH
 60H  30/0600Z 15.8N 112.7W   75 KT  85 MPH
 72H  30/1800Z 16.0N 113.7W   70 KT  80 MPH
 96H  01/1800Z 16.4N 115.1W   50 KT  60 MPH
120H  02/1800Z 17.3N 115.0W   35 KT  40 MPH
 
$$
Forecaster Berg
 
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