Atlantic Basin Tropical Cyclones

Tropical Storm Earl Forecast Discussion


428 
WTNT41 KNHC 061454
TCDAT1

Tropical Storm Earl Discussion Number  15
NWS National Hurricane Center Miami FL       AL062022
1100 AM AST Tue Sep 06 2022

The structure of Earl this morning is trying to regroup, though 
strong westerly vertical wind shear continues to affect the system. 
A new burst of deep convection has been attempting to form a little 
closer to the low-level center. Morning data from the NOAA-P3 
Hurricane Reconnaissance mission show that the mid-level center has 
shifted back downshear of the center, though the vertical depth of 
the overall circulation is deeper than 24 hours ago. The peak flight 
winds from the mission were 62 kt at 700mb, with SFMR values in the 
50-55 kt range. The initial intensity is maintained at 55 kt for 
this advisory, which is also in line with the subjective Dvorak 
estimates. 

Earl took a bit of a jog to the northwest this morning, but the 
larger mean motion is still generally northward at 360/4 kt. The 
gentle mid-level ridging that has been overhead of Earl is forecast 
to gradually break down and shift off to the southeast, as a 
positively-tilted deep-layer trough moves offshore of the eastern 
United States. Ultimately, this trough is expected to capture the 
tropical cyclone, helping Earl to recurve to the northeast in the 
2-4 day forecast period. How sharp and fast this turn to the 
northeast though remains uncertain, with the GFS showing a slower 
turn in comparison to some of the other guidance. The updated NHC 
track forecast lies very close to the previous official forecast, 
closest to the HCCA consensus aid, and roughly in between the 
westward GFS and eastward ECMWF for the first 72 hours of the 
forecast period.

Strong 25-30 kt of vertical wind shear is expected to keep Earl in 
check today, with little intensification forecast in the short 
term. However, shear begins to decrease markedly in about 36 h, 
with both the GFS- and ECMWF-SHIPS shear dropping under 10 kt in 
60-72 hours. Thus, the latest forecast continues to indicate Earl 
becoming a major hurricane around that time-frame. After 96 h, Earl 
is forecast to begin undergoing extratropical transition, with the 
latest forecast indicating that process completing by day 5.

Earl's center is expected to pass to the southeast of Bermuda in 
60-72 hours. However, the size of the wind field of the tropical 
cyclone is expected to increase significantly, and interests on the 
island should continue to monitor the progress of the storm closely.


FORECAST POSITIONS AND MAX WINDS

INIT  06/1500Z 23.7N  65.7W   55 KT  65 MPH
 12H  07/0000Z 24.4N  65.8W   55 KT  65 MPH
 24H  07/1200Z 25.5N  65.7W   60 KT  70 MPH
 36H  08/0000Z 26.8N  65.5W   70 KT  80 MPH
 48H  08/1200Z 28.6N  65.0W   80 KT  90 MPH
 60H  09/0000Z 30.6N  63.8W   95 KT 110 MPH
 72H  09/1200Z 33.0N  61.4W  100 KT 115 MPH
 96H  10/1200Z 39.3N  52.8W   95 KT 110 MPH
120H  11/1200Z 44.0N  44.0W   65 KT  75 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin




Source link