Pacific Hurricane Feed

Tropical Storm Frank Forecast Discussion

WTPZ42 KNHC 291437

Tropical Storm Frank Discussion Number  14
NWS National Hurricane Center Miami FL       EP072022
900 AM MDT Fri Jul 29 2022

In infrared imagery, Frank's appearance has not changed much since 
the last advisory.  While the system shows a large curved 
convective band that wraps a little more than three-quarters of the 
way around the center, the central deep convection is a bit ragged, 
possibly due to dry air entrainment from the northwest.  However, 
recent 37 GHz microwave data shows the cyclone has developed a 
good low-level structure, with a ring of shallow to moderate 
convection surrounding a 40 n mi wide developing eye.  Satellite 
intensity estimates have changed little since the previous 
advisory, so the initial intensity remains 55 kt.

Frank will be in an environment of light vertical shear and over 
sea surface temperatures of 28-29C for the next 36 h, and the 
inner-core structure seen in the microwave imagery favors a faster 
rate of strengthening. The one current negative factor is the dry 
air entrainment that is causing the inner core deep convection to 
sputter.  The intensity forecast assumes strengthening will resume 
as the deep convection will becomes persistent, and it follows the 
trend of the intensity guidance in calling for a peak intensity of 
90 kt in 36 h. After that time, Frank should move over 
progressively cooler SSTs, with the system reaching 21C water by  
120 h.  This should cause steady to rapid weakening, and Frank is 
forecast to become a remnant low by the end of the forecast period.

The initial motion is now 300/10 kt.  Frank is moving along the 
southwest side of the subtropical ridge over northwestern Mexico, 
and it should move generally northwestward during the forecast 
period toward a developing break in the ridge west of California. 
The track guidance is in good agreement with this scenario and has 
changed little since the previous advisory. Thus, the new forecast 
track is an update of the previous forecast.

It again should be noted that Frank and Tropical Storm Georgette
are expected to come close enough to one another for some
interaction.  Frank will be the larger and dominant system during
this interaction, and Georgette will have little impact on the track
or intensity of Frank.


INIT  29/1500Z 14.2N 113.0W   55 KT  65 MPH
 12H  30/0000Z 15.3N 114.3W   65 KT  75 MPH
 24H  30/1200Z 16.5N 116.1W   80 KT  90 MPH
 36H  31/0000Z 17.7N 117.9W   90 KT 105 MPH
 48H  31/1200Z 18.9N 119.6W   85 KT 100 MPH
 60H  01/0000Z 20.2N 121.2W   75 KT  85 MPH
 72H  01/1200Z 21.5N 122.8W   65 KT  75 MPH
 96H  02/1200Z 24.0N 126.0W   40 KT  45 MPH
120H  03/1200Z 26.0N 128.5W   25 KT  30 MPH...POST-TROP/REMNT LOW

Forecaster Beven

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