Eastern Pacific Basin Tropical Cyclones

Tropical Storm Georgette Forecast Discussion


000
WTPZ43 KNHC 281538 CCA
TCDEP3

Tropical Storm Georgette Discussion Number   5...Corrected
NWS National Hurricane Center Miami FL       EP082022
800 AM PDT Thu Jul 28 2022

Corrected typo in first paragraph

Georgette's structure on conventional satellite imagery remains 
distinct this morning, with a small yet intense central dense 
overcast with cloud tops as cold at -80 C near where the center is 
estimated currently. The 1 minute GOES-17 data, in combination with 
some cyclonically rotating GLM flashes, has been helpful in 
determining the center location on first-light visible, which 
appears more embedded in the convection than previously expected. A 
1234 UTC SSMIS microwave pass also hints at this more embedded 
structure. The initial intensity remains 45-kt in closest agreement 
with the 1200 UTC Dvorak estimate from TAFB. 

Georgette's center may have relocated a bit closer to the convection 
this morning, but the current motion is still estimated at south of 
due west at 260/9 kt. As previously discussed, a northeast to 
southwest-oriented ridge should continue to steer Georgette 
west-southwestward or southwestward for the next 12-24 hours, and 
the guidance is in decent agreement of the track during this time 
frame. However, after 24 hours, the track forecast becomes highly 
problematic as the larger circulation of Frank approaches from the 
east. The majority of the deterministic track aids respond to Frank 
by quickly absorbing Georgette into its larger circulation, with the 
trackers quickly shifting to the center of Frank between the 36-60 
hour forecast. However, this apparent absorption solution is not a 
done deal, and there is a non-negligible number of European ensemble 
members that keep Georgette a distinct feature beyond the next 2-3 
days. In addition, it is primarily the stronger and rightward 
ensemble track members that have this solution, and Georgette is 
already stronger and right-of-track compared to much of the 
deterministic guidance this morning. For these reasons, the latest 
track forecast was nudged further west compared to the previous one, 
attempting to the account for the possibility that the 
stronger-rightward ECMWF ensemble members could verify, and now 
shows dissipation at 120 hours, which is a little later than the 
previous forecast. Needless to say though, the track forecast has 
higher-than-normal uncertainty due to the difficulty in forecasting 
these binary TC interactions.

Intensity-wise, Georgette still could intensify a bit more today in 
a moderate easterly shear environment while over 28-29 C sea-surface 
temperatures. However, mid-level relative humidity diagnosed by 
SHIPS guidance remains quite low, and the shear could still import 
dry air into Georgette's tiny core and disrupt its current 
convective structure. After today, the majority of the guidance 
either maintains or weakens the tropical storm, and the latest 
intensity forecast will continue to show a steady state 50-kt 
tropical storm from 24-48 hours. Assuming Frank does get close to 
Georgette, its easterly upper-level outflow and westerly low-level 
inflow could further increase the shear after 48 hours, and gradual 
weakening is shown after that time. At 120 hours, Georgette is 
forecast to open up into a trough as Frank either absorbs it or 
passes by to its north. The NHC intensity forecast is in closest 
agreement to the latest LGEM guidance.


FORECAST POSITIONS AND MAX WINDS

INIT  28/1500Z 15.8N 118.7W   45 KT  50 MPH
 12H  29/0000Z 15.2N 119.8W   50 KT  60 MPH
 24H  29/1200Z 14.5N 121.0W   50 KT  60 MPH
 36H  30/0000Z 14.0N 121.9W   50 KT  60 MPH
 48H  30/1200Z 13.9N 122.3W   50 KT  60 MPH
 60H  31/0000Z 13.8N 122.7W   45 KT  50 MPH
 72H  31/1200Z 14.0N 123.0W   40 KT  45 MPH
 96H  01/1200Z 14.8N 123.0W   40 KT  45 MPH
120H  02/1200Z...DISSIPATED

$$
Forecaster Papin



Source link