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Tropical Storm Kristy Discussion Number   4
NWS National Hurricane Center Miami FL       EP122024
800 AM MST Tue Oct 22 2024
 
Kristy still appears to be on an intensification trend this morning.
The storm's structure on satellite imagery is quite well organized, 
with a large curved band on its western side, and a smaller central 
dense overcast that suggests a formative inner core may be 
developing.  There has not been much passive microwave imagery for 
a more in-depth look at the convective structure since the prior 
advisory, but based on a blend of the subjective Dvorak intensity 
estimates (T3.0/45 kt from TAFB and T3.5/55 kt from SAB), the 
initial intensity is being increased to 50 kt for this advisory.
 
The tropical storm is moving a little north of due west this
morning, with the motion estimated at 280/15 kt. A well-established 
subtropical mid-level ridge should continue to steer the tropical 
cyclone westward, with some of the guidance even showing a little 
farther south of due west over the next 48-60 h. By this weekend, 
the ridge becomes eroded towards its western edge by a mid- to 
upper-level trough that should allow Kristy to begin gaining 
latitude on Friday into the weekend. The track forecast this cycle 
is nearly on top of the previous NHC track forecast for the first 48 
h, and is a little to the south and west thereafter, blending the 
consensus aids TCVE and HCCA with the prior track at the end of the 
forecast period.
 
As alluded to in previous discussions, the environment appears quite
favorable for intensification, with low shear, warm sea-surface
temperatures, and a moist surrounding environment. In fact, rapid
intensification is becoming a distinct possibility as the storm
forms an inner core. Indeed, the latest ECMWF-SHIPS guidance is 
giving Kristy a 43 percent chance of a 45-kt increase in intensity 
over the next 36 h. The latest NHC intensity forecast thus was 
increased over the next couple of days, and now peaks Kristy as a 
110 kt category 3 hurricane in 60-72 h. It is worth noting that the
hurricane-regional model guidance mean is still a little above
that peak intensity. After 72 h, the same upper-level trough eroding
the subtropical ridge should also contribute to a rapid increase in
southwesterly vertical wind shear over Kristy as it also moves over
increasingly cool ocean waters. Thus, a fast rate of weakening is
likely to begin by this weekend, in good agreement with the IVCN and
HCCA consensus aids.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/1500Z 14.7N 106.6W   50 KT  60 MPH
 12H  23/0000Z 14.6N 109.4W   60 KT  70 MPH
 24H  23/1200Z 14.4N 112.6W   75 KT  85 MPH
 36H  24/0000Z 14.3N 116.2W   90 KT 105 MPH
 48H  24/1200Z 14.2N 119.4W  105 KT 120 MPH
 60H  25/0000Z 14.3N 122.5W  110 KT 125 MPH
 72H  25/1200Z 15.0N 125.2W  110 KT 125 MPH
 96H  26/1200Z 18.0N 129.5W   80 KT  90 MPH
120H  27/1200Z 20.5N 133.5W   50 KT  60 MPH
 
$$
Forecaster Papin/Torres-Vazquez
 
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