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Tropical Storm Nicholas Special Discussion Number   4
NWS National Hurricane Center Miami FL       AL142021
1130 PM CDT Sun Sep 12 2021

The center of Nicholas has re-formed about 150 n mi to the 
north-northwest of the previous feature we were tracking, as 
confirmed by aircraft reconnaissance and Brownsville radar, and 
this large change necessitates a special advisory. The initial wind 
speed is set to 45 kt, a blend of the reduced 56-kt flight level 
winds and 45-50 kt SFMR values recently found by the plane.  

Because of the re-formation, the track forecast has been accelerated 
to indicate a landfall about 12 hours sooner than the last advisory. 
The intensity forecast is about 5 kt stronger in the short term, 
but actually ends up near the same intensity at landfall as the 
last advisory because of less time over water.  The track forecast 
is blended with the previous one after landfall, and the intensity 
forecast is lower after landfall because it is farther inland.

No changes to the watches or warnings are required at this time.

 
Key Messages:
 
1.  Periods of heavy rainfall are expected to impact portions of the
Texas and Louisiana coasts through the middle of the week.
Significant rainfall amounts are possible, potentially resulting in
areas of considerable flash and urban flooding, especially in highly
urbanized metropolitan areas. Isolated minor to moderate river
flooding is also expected.
 
2. There is the danger of life-threatening storm surge inundation
along the coast of Texas from Port Aransas to San Luis Pass.
Residents in these areas should follow any advice given by
local officials.
 
3. Nicholas is forecast to approach the middle Texas coast as a
strong tropical storm on Monday, and could be near hurricane 
intensity if it moves to the right of the forecast track and 
remains over water longer. Tropical storm conditions are
expected along portions of the middle Texas coast beginning Monday, 
with hurricane conditions possible from Port Aransas to
Freeport late Monday and Monday night.
 
4. Tropical storm conditions are expected along portions of the
northeastern coast of Mexico and the coast of south Texas beginning
Monday morning.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  13/0430Z 24.8N  96.3W   45 KT  50 MPH
 12H  13/1200Z 26.0N  96.7W   50 KT  60 MPH
 24H  14/0000Z 28.0N  96.6W   55 KT  65 MPH
 36H  14/1200Z 29.4N  96.3W   45 KT  50 MPH...INLAND
 48H  15/0000Z 30.2N  95.6W   35 KT  40 MPH...INLAND
 60H  15/1200Z 30.8N  94.9W   30 KT  35 MPH...INLAND
 72H  16/0000Z 31.3N  94.2W   25 KT  30 MPH...INLAND
 96H  17/0000Z 31.7N  92.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  18/0000Z...DISSIPATED
 
$$
Forecaster Blake
 
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