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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
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