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Hurricane Nora Discussion Number  15
NWS National Hurricane Center Miami FL       EP142021
400 AM CDT Sun Aug 29 2021

There have been no recent in-situ observations for estimating the 
intensity of Nora, but the cyclone is still fairly well-organized on 
satellite images.  Taking a blend of T- and Current Intensity 
numbers from TAFB and SAB along with ADT estimates from UW-CIMSS 
still supports keeping the system as a hurricane at this time.

Center fixes indicate that Nora is moving a little west of due 
north at a decreased forward speed, or around 350/9 kt.  The 
tropical cyclone is expected to move north-northwestward to 
northwestward during the next few days, on the southwestern side of 
a mid-level ridge.  This would take Nora over the eastern part of 
the Gulf of California, but very near the coast of mainland Mexico 
over the next few days.  The track guidance has shifted somewhat to 
the east, and now suggests that it is a very distinct possibility 
that the system will move inland much sooner than shown by the 
latest NHC track forecast.

The future intensity of Nora is of course highly dependent on how 
soon the center moves inland.  The official intensity forecast 
assumes that the system will remain just offshore so that only slow 
weakening will occur during the next 72 hours or so.  This is in 
good agreement with the NOAA corrected consensus guidance.  
Alternatively, Nora may move inland sooner than indicated, in which 
case the system would probably dissipate in 2 to 3 days or less.  
Obviously, this intensity forecast is of low confidence. 
 
 
Key Messages:
 
1. Nora is forecast to be at or near hurricane strength while
it moves near the coasts of Nayarit and Sinaloa through the
weekend and into Monday, and hurricane warnings or watches 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 the west coast 
of Mexico from the states of Colima northward to southern Sonora.  
This rain will likely result in life-threatening flash flooding and 
mudslides across these regions.  Rainfall from Nora is likely to 
spread into the southwestern U.S. and central Rockies during the 
middle to latter portion of the week, bringing the potential for 
flash flooding to the region. 
 
3. Nora is forecast to move north-northwestward to northwestward 
over the Gulf of California Tuesday and Wednesday, bringing a risk 
of wind impacts to portions of the Mexican states of Baja California 
Sur, northern Sinaloa, and Sonora.  Given the above-average 
uncertainty in the forecast intensity, confidence is not high enough 
to determine the magnitude and location of these potential impacts.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/0900Z 22.5N 105.9W   65 KT  75 MPH
 12H  29/1800Z 23.6N 106.8W   65 KT  75 MPH
 24H  30/0600Z 24.2N 107.4W   60 KT  70 MPH
 36H  30/1800Z 24.7N 108.1W   60 KT  70 MPH
 48H  31/0600Z 25.2N 108.8W   60 KT  70 MPH
 60H  31/1800Z 26.0N 109.5W   55 KT  65 MPH
 72H  01/0600Z 27.0N 110.2W   55 KT  65 MPH
 96H  02/0600Z 29.5N 111.0W   30 KT  35 MPH...INLAND
120H  03/0600Z...DISSIPATED
 
$$
Forecaster Pasch
 
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