Eastern Pacific Basin Tropical Cyclones

Tropical Storm Georgette Forecast Discussion


000
WTPZ43 KNHC 272053
TCDEP3

Tropical Storm Georgette Discussion Number   2
NWS National Hurricane Center Miami FL       EP082022
200 PM PDT Wed Jul 27 2022

The satellite presentation of the tropical cyclone this afternoon
remains well organized, albeit very compact. The well curved band
seen earlier this morning on microwave has evolved into a small
central dense overcast with cloud top temperatures of -70 to -75 C,
and the center estimated to be embedded within this cirrus canopy.
Dvorak satellite estimates from the various agencies were T2.5/35-kt
from TAFB, T2.0/30-kt from SAB, and T2.4/34-kt from UW-CIMSS ADT.
Unfortunately today's ASCAT swaths missed the small wind field of
the cyclone, but given the healthy structure seen on satellite
imagery and the higher subjective and objective estimates, the
initial intensity is set at 35-kt, upgrading Tropical Depression
Eight-E to Tropical Storm Georgette.

Georgette has been moving just north of due west today with the 
motion estimated at 275/8 kt. For the first 24 hours, the storm's 
motion is expected to gradually bend westward and then 
west-southwestward as its influenced by a weak mid-level ridge 
oriented southwest-to-northeast ahead of the cyclone. Afterwards, 
the track forecast becomes increasingly uncertain and complex. As 
mentioned previously, larger tropical storm Frank will be 
approaching Georgette from the east, and its outer wind field will 
likely have some influence on Georgette's motion. Subtle differences 
in structure and distance between Frank and Georgette could have 
large implications on how far westward Georgette gets in the 3-4 day 
forecast period. This is illustrated by the most recent ECMWF 
ensemble tracks, which show an across-track spread of more than 500 
n mi in just 72 hours, which is roughly 5 times the average forecast 
track error at that forecast period. To add to the uncertainty, the 
GFS and UKMET models do not appear to capture the tiny vortex of 
Georgette well in their most recent cycle, and quickly absorb it in 
Frank's larger circulation. Favoring a solution that keeps Georgette 
a separate entity, the latest track forecast leans more heavily on a 
blend between the ECMWF, its ensemble mean, and Canadian, which 
mostly keep Georgette as a coherent feature through the forecast 
period. This track is further north of the previous track early on, 
and also takes Georgette further west over the next 3 days. 
Afterwards, The larger monsoonal flow that is expected to wrap up 
into Frank's larger circulation will likely also capture Georgette, 
and a sharp turn to the north and north-northeast is now predicted 
at the end of the forecast period. This current track forecast 
remains low confidence and larger-than normal adjustments may be 
necessary if Frank ends up getting closer and exerting more 
influence on Georgette's track than currently indicated here.

The intensity forecast also remains challenging, both due to the 
small size of Georgette, and the looming potential for its 
interaction with Frank located further east. Easterly vertical wind 
shear of 10-15 knots is expected to continue for the next couple of 
days as the storm traverses over 28-29 C sea surface temperatures in 
a relatively dry mid-level environment. The small structure of 
Georgette also hints at the the potential for rapid intensity 
changes, both up or down. Assuming occasional dry-air entrainment 
could occur, only gradual intensification is shown over the next 36 
hours, peaking Georgette as a 50 kt tropical storm. After that time, 
the outflow from Frank to its east may result in a more hostile 
environment, and most of the intensity guidance levels off at that 
time. At the end of the forecast, Georgette is expected to move over 
cooler SSTs and even higher shear, which could begin a weakening 
trend. The latest intensity forecast is a bit higher than the 
previous cycle, but is in fairly good agreement with the latest HCCA 
and IVCN consensus aids. This intensity forecast is also low 
confidence. 


FORECAST POSITIONS AND MAX WINDS

INIT  27/2100Z 16.5N 115.9W   35 KT  40 MPH
 12H  28/0600Z 16.2N 117.1W   40 KT  45 MPH
 24H  28/1800Z 15.6N 118.7W   45 KT  50 MPH
 36H  29/0600Z 15.2N 120.1W   50 KT  60 MPH
 48H  29/1800Z 14.8N 121.5W   50 KT  60 MPH
 60H  30/0600Z 14.6N 122.3W   50 KT  60 MPH
 72H  30/1800Z 14.6N 123.5W   50 KT  60 MPH
 96H  31/1800Z 15.3N 123.5W   45 KT  50 MPH
120H  01/1800Z 17.8N 121.6W   40 KT  45 MPH

$$
Forecaster Papin



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