Tropical Storm Gilma Forecast Discussion

000
WTPZ42 KNHC 182042
TCDEP2

Tropical Storm Gilma Discussion Number   2
NWS National Hurricane Center Miami FL       EP072024
200 PM MST Sun Aug 18 2024

Despite continued moderate easterly vertical wind shear, deep 
convection has been expanding and has now built over the center of 
the system.  Accordingly, the Dvorak estimates have nudged upward 
and are now between 30 and 35 kt.  Based on those classifications 
and the improving convective pattern, the initial intensity is 
increased to 35 kt, making the system Tropical Storm Gilma.

Moderate easterly vertical wind shear of about 20 kt is expected to 
continue during the next day or so, which should limit the amount of 
strengthening in the short term.  The shear is expected to lessen 
some after that, and the somewhat more favorable upper-level wind 
environment combined with warm waters and a relatively moist 
atmosphere should allow for gradual strengthening throughout much of 
the week.  The NHC intensity forecast is higher than the previous 
one and roughly between the HCCA and IVCN guidance.

Gilma is moving west-northwestward, or 285 degrees, at 12 kt.  A 
high pressure ridge situated to the system’s north should cause the 
storm to move westward to west-northwestward at about the same speed 
during the next couple of days.  Later in the week, the models show 
the ridge weakening as a trough amplifies off the west coast of the 
U.S., which should cause the system to slow down and turn a bit to 
the right.  There is quite a bit of along-track spread in the 
models, with the GFS being the slowest model and HWRF/HAFS the 
fastest.  The NHC track forecast is similar to the previous one 
through 60 h and then is a little to the north of the prior track 
after that.  This forecast is close to the various consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT  18/2100Z 14.7N 112.3W   35 KT  40 MPH
 12H  19/0600Z 15.1N 114.0W   40 KT  45 MPH
 24H  19/1800Z 15.6N 116.1W   40 KT  45 MPH
 36H  20/0600Z 15.9N 118.1W   45 KT  50 MPH
 48H  20/1800Z 16.2N 119.9W   50 KT  60 MPH
 60H  21/0600Z 16.6N 121.3W   55 KT  65 MPH
 72H  21/1800Z 16.9N 122.5W   60 KT  70 MPH
 96H  22/1800Z 17.7N 125.0W   70 KT  80 MPH
120H  23/1800Z 18.6N 127.1W   70 KT  80 MPH

$$
Forecaster Cangialosi