Eastern Pacific Basin Tropical Cyclones

Tropical Storm Frank Forecast Discussion


549 
WTPZ42 KNHC 290839
TCDEP2

Tropical Storm Frank Discussion Number  13
NWS National Hurricane Center Miami FL       EP072022
300 AM MDT Fri Jul 29 2022

Although there has been an increase in banding over the eastern
semicircle of Frank overnight, some entrainment of dry air over the
northwestern portion of the circulation appears to have temporarily
caused a pause in the recent intensification.  Frank's outflow has
become better established, and the latest shear analysis from
UW/CIMSS shows that the shear has decreased to less than 10 kt.
Recent scatterometer data was very helpful in pinpointing the
center and it revealed maximum winds of around 45 kt.  The ASCAT
data also indicated that the wind field has expanded over the
eastern semicircle.  Subjective satellite intensity estimates from
TAFB and SAB are 55 and 65 kt, respectively.  The advisory intensity
has been kept at 55 kt, in line with the TAFB classification and
allowing for some undersampling of the ASCAT satellite.

Although the vertical shear over Frank has diminished, the
lack of an inner core in recent microwave imagery and the fairly
large wind field suggest it may take a little more time before the
rate of strengthening increases.  The SHIPS RI and DTOPS guidance
gives about a 50/50 shot of rapid strengthening over the next 24
hours, however the NHC foreast is slightly below that given the
above mentioned structure of the storm. The NHC forecast still
calls for Frank to become a hurricane later today, and steady
strengthening is likely through 36 hours.  By 48 hours, Frank will
be moving over progressively cooler water and into a more stable
environment.  This will lead to steady weakening, and Frank is
forecast to become a post-tropical cyclone by day 5.

Frank is moving west-northwestward or 295/9 kt.  The storm is
currently being steered around the southwestern periphery of a
subtropical ridge near northwestern Mexico.  A weakness is forecast
to develop in the ridge over the next couple of days which will
cause Frank to turn more poleward. The spread in the dynamical
models has continued to decrease and the latest NHC forecast track
is near the center of the tightly clustered guidance envelope.

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.


FORECAST POSITIONS AND MAX WINDS

INIT  29/0900Z 13.6N 112.2W   55 KT  65 MPH
 12H  29/1800Z 14.4N 113.5W   65 KT  75 MPH
 24H  30/0600Z 15.5N 115.2W   80 KT  90 MPH
 36H  30/1800Z 16.8N 117.0W   90 KT 105 MPH
 48H  31/0600Z 18.0N 118.7W   90 KT 105 MPH
 60H  31/1800Z 19.2N 120.4W   80 KT  90 MPH
 72H  01/0600Z 20.4N 122.1W   70 KT  80 MPH
 96H  02/0600Z 22.8N 125.2W   45 KT  50 MPH
120H  03/0600Z 25.0N 128.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brown




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