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Tropical Storm Fiona Discussion Number  16
NWS National Hurricane Center Miami FL       AL072022
500 AM AST Sun Sep 18 2022
 
Fiona has continued to show signs of better organization in Doppler 
radar data from San Juan this morning, and earlier data from an Air 
Force Hurricane Hunter aircraft indicate that the storm has indeed 
strengthened. The aircraft reported peak flight-level (700 mb) winds 
of 57 kt, along with several instances of SFMR winds greater than 50 
kt and a peak of 57 kt in the northeastern quadrant of the storm. 
Also, a center dropsonde indicated that the minimum pressure had 
fallen a few millibars to 994 mb. Based on these data, the initial 
intensity is raised to 55 kt for this advisory.

After a brief northward jog last night, the center of Fiona appears 
to have resumed a more west-northwestward heading (290/7 kt). The 
storm is expected to turn northwestward later today, which should 
bring the center of Fiona near or over the southwestern portion of 
Puerto Rico this afternoon and near the northern coast of the 
Dominican Republic early Monday. Then, a mid-level trough over the 
southwestern Atlantic is forecast to induce a weakness in the 
steering ridge early next week. This should enable Fiona to turn 
slowly northward by midweek while it passes near or to the east of 
the Turks and Caicos Islands. An acceleration to the north and 
north-northeast is forecast by late in the week as Fiona moves 
within the flow ahead of an amplifying mid- to upper-level trough. 
The models are tightly clustered throughout the forecast period and 
no major changes were made to the NHC track forecast, which still 
lies close to the consensus aids near the center of the guidance 
envelope.  
 
Moderate southwesterly to westerly shear appears likely to continue 
affecting Fiona during the next several days. However, very warm 
sea-surface temperatures and sufficient mid-level moisture are still 
expected to allow for some intensification as Fiona approaches 
Puerto Rico and the Dominican Republic. The NHC forecast calls for 
Fiona to become a hurricane later today before it moves near or over 
Puerto Rico. Once the cyclone moves away from land and reaches the 
southwestern Atlantic, more significant strengthening is forecast in 
agreement with the consensus of the intensity guidance. The latest 
NHC intensity forecast has been raised from 48 h through the end of 
the forecast period, but still lies slightly below the IVCN and HCCA 
aids. Fiona could reach major hurricane strength by late this week 
over the western Atlantic.
 
 
Key Messages:
 
1.  Hurricane conditions are expected across portions of Puerto Rico 
today, and are expected in portions of the Dominican Republic 
tonight and Monday. Tropical storm conditions are occurring across 
the U.S. and British Virgin Islands and are spreading westward 
across Puerto Rico. Tropical storm conditions will reach the 
Dominican Republic later today and tonight.
 
2. Heavy rains from Fiona will continue across Puerto Rico through 
tonight and occur over the Dominican Republic later today into 
Monday. These rainfall amounts will produce life-threatening flash 
floods and urban flooding across Puerto Rico and portions of the 
eastern Dominican Republic, along with mudslides and landslides in 
areas of higher terrain.
 
3. Fiona is forecast to strengthen after moving away from Puerto 
Rico and the Dominican Republic. Tropical storm conditions are 
possible in the Turks and Caicos Islands and the southeastern 
Bahamas by late Monday or early Tuesday, and a Tropical Storm Watch 
has been issued for these locations.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/0900Z 17.1N  65.8W   55 KT  65 MPH
 12H  18/1800Z 17.8N  66.9W   65 KT  75 MPH
 24H  19/0600Z 18.7N  68.0W   65 KT  75 MPH
 36H  19/1800Z 19.8N  69.0W   70 KT  80 MPH
 48H  20/0600Z 21.2N  69.8W   80 KT  90 MPH
 60H  20/1800Z 22.6N  70.5W   85 KT 100 MPH
 72H  21/0600Z 23.9N  70.7W   90 KT 105 MPH
 96H  22/0600Z 27.5N  70.0W   95 KT 110 MPH
120H  23/0600Z 33.0N  66.0W   95 KT 110 MPH
 
$$
Forecaster Reinhart
 
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