Atlantic Basin Tropical Cyclones

Subtropical Storm Nicole Forecast Discussion


000
WTNT42 KNHC 070900
TCDAT2

Subtropical Storm Nicole Discussion Number   1
NWS National Hurricane Center Miami FL       AL172022
500 AM AST Mon Nov 07 2022

The area of disturbed weather that NHC has been monitoring over the 
southwestern Atlantic Ocean has been gradually becoming better 
organized.  Scatterometer data and buoy observations from last 
evening indicated that the system has developed a sufficiently 
well-defined center of circulation, with gale-force winds as high as 
40 kt occurring in a band that lies between 180-240 n mi to the east 
of the center.  Moderate to deep convection has also increased a 
bit, with TAFB providing a subtropical Hebert-Poteat classification 
of ST1.5.  Given these data, the system is now being classified as a 
subtropical storm.

Since Nicole's center has only recently formed, the initial motion 
is a little uncertain, but the best estimate is north-northwestward, 
or 330/12 kt.  Model guidance indicates that the system should turn 
northwestward and slow down later today, followed by a turn toward 
the west and west-southwest tonight through Tuesday night due to a 
mid-level ridge axis poking eastward off the U.S. Mid-Atlantic 
coast.  In about 3 days, the high over the southeastern United 
States will slide eastward over the Atlantic as a large mid-latitude 
trough traverses the country, and Nicole is expected to make a sharp 
recurvature toward the north and northeast on days 4 and 5 in the 
vicinity of Florida.  The track guidance is in fairly good agreement 
on this scenario, and the official NHC track forecast is fairly 
close to the TVCN and HCCA consensus aids. 

Some gradual strengthening is anticipated over the next few days, 
although Nicole's sprawling nature does not favor fast 
intensification, at least not initially.  For the first couple of 
days of the forecast, the NHC intensity prediction closely follows 
the GFS global model solution.  Although Nicole is likely to 
maintain a large wind field, models suggest that it could make a 
transition to a tropical cyclone and develop a smaller inner-core 
wind field in about 2 to 3 days, and at that point more significant 
intensification is possible.  For now, the NHC intensity forecast 
brings Nicole close to hurricane strength in 60-72 hours while it 
moves near the northwestern Bahamas and approaches the east coast of 
Florida, which is in line with the HCCA consensus aid.  It's not out 
of the question for Nicole to reach hurricane strength, especially 
given how warm the waters are in the vicinity of the Bahamas.  It 
should be stressed, however, that no matter Nicole's ultimate 
intensity, the storm's large size will likely cause significant 
wind, storm surge, and rainfall impacts over a large portion of the 
northwestern Bahamas, Florida, and the southeastern coast of the 
United States during much of the upcoming week.

Key Messages:

1.  Nicole is forecast to be a large storm, and regardless of its 
exact path, widespread impacts from a prolonged period of coastal 
flooding, tropical-storm-force winds, heavy rainfall, rough surf 
and rip currents, and beach erosion are likely along much of the 
southeastern United States coast, the Florida east coast, and 
portions of the northwestern and central Bahamas during much of the 
upcoming week.

2.  Nicole could be at or near hurricane strength when it moves 
near the northwestern Bahamas and the east coast of Florida 
Wednesday and Thursday, bringing the potential for a dangerous 
storm surge, damaging winds, and heavy rainfall to a portion of 
those areas.  A Tropical Storm Watch is now in effect for the 
northwestern Bahamas, and additional watches could be required for 
portions of the Bahamas and the coast of Florida later today.


FORECAST POSITIONS AND MAX WINDS

INIT  07/0900Z 25.5N  68.5W   40 KT  45 MPH
 12H  07/1800Z 26.3N  69.3W   40 KT  45 MPH
 24H  08/0600Z 27.5N  70.5W   45 KT  50 MPH
 36H  08/1800Z 28.2N  72.3W   50 KT  60 MPH
 48H  09/0600Z 27.6N  74.9W   55 KT  65 MPH...TROPICAL CYCLONE
 60H  09/1800Z 26.8N  77.3W   60 KT  70 MPH
 72H  10/0600Z 27.0N  79.5W   60 KT  70 MPH
 96H  11/0600Z 29.2N  83.3W   45 KT  50 MPH
120H  12/0600Z 32.8N  80.9W   45 KT  50 MPH...INLAND

$$
Forecaster Berg



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