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Tropical Storm Nora Discussion Number  10
NWS National Hurricane Center Miami FL       EP142021
1000 PM CDT Fri Aug 27 2021

Nora's cloud pattern has not become much better organized since 
earlier today.  The central convection has diminished, but this is 
likely a diurnal fluctuation.  Upper-level outflow appears to be 
fairly well-defined, with convective banding features most 
prominent over the southern portion of the circulation.  Dvorak 
intensity estimates from both TAFB and SAB remain at 55 kt, so the 
advisory intensity will be held at that value for now.

The storm has been moving a little to the east of the previous 
track over the past few hours, but the longer-term motion estimate 
is still northwestward, or 325/9 kt.  Nora should move on a 
northwestward or north-northwestward heading for the next 2-3 days 
on the southwestern side of a mid-tropospheric anticyclone.  Late 
in the forecast period, the cyclone is forecast to turn northward 
as the ridge to its north weakens.  The official forecast track has 
been nudged just a bit to the east of the previous one during the 
next 72 hours or so, but not as far east as the latest dynamical 
model consensus, TVCE.

Nora is expected to be in a moist, low-shear environment for the 
next few days, so the atmospheric conditions should favor 
intensification into a hurricane.  Nonetheless, the majority of the 
intensity guidance does not show much strengthening beyond 24 hours, 
probably due to land interaction.  The official intensity forecast 
shows gradual strengthening for the next couple of days or so, and 
is similar to the previous one.  This is close to the LGEM guidance 
based on the ECMWF global model fields.  It should be noted that 
there is significant uncertainty in the future strength of Nora 
because of the possible influence of land.

 
Key Messages:
 
1. Nora is forecast to strengthen to a hurricane on Saturday while
passing nearby the coasts of the Mexican states of Jalisco and
Nayarit, and hurricane watches and tropical storm warnings are
in effect for portions of that coastline.  Interests in these areas
should closely monitor the progress of Nora and subsequent updates
to the forecast.
 
2.Heavy rain associated with Nora is expected across coastal 
sections of the Mexican states of Guerrero, Michoacan, Colima, and 
Jalisco, as well as Baja California Sur.  Life-threatening flash 
flooding and mudslides are expected.

3. Nora is forecast to move over the Gulf of California as a
hurricane early next week, bringing a risk of wind and rain impacts
to portions of the Mexican states of Baja California Sur, Sinaloa,
and Sonora.  Given the above-average uncertainty in the forecast,
it is still too soon to determine the magnitude and location of
these potential impacts.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/0300Z 16.3N 105.1W   55 KT  65 MPH
 12H  28/1200Z 17.6N 105.6W   60 KT  70 MPH
 24H  29/0000Z 19.6N 106.2W   65 KT  75 MPH
 36H  29/1200Z 21.6N 107.0W   70 KT  80 MPH
 48H  30/0000Z 22.7N 107.9W   75 KT  85 MPH
 60H  30/1200Z 23.6N 108.6W   80 KT  90 MPH
 72H  31/0000Z 24.5N 109.3W   80 KT  90 MPH
 96H  01/0000Z 26.5N 111.0W   70 KT  80 MPH
120H  02/0000Z 29.5N 111.5W   45 KT  50 MPH...INLAND
 
$$
Forecaster Pasch
 
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