Pacific Hurricane Feed

Tropical Storm Ivette Forecast Discussion

WTPZ45 KNHC 152044

Tropical Storm Ivette Discussion Number   9
NWS National Hurricane Center Miami FL       EP102022
300 PM MDT Mon Aug 15 2022

The burst of deep convection that developed around the time of the
release of the previous advisory appears to have resulted in some
unexpected intensification of the cyclone.  A 1650 UTC ASCAT-B
overpass revealed a fairly sizable area of 30-35 kt winds over the
western portion of the circulation. While some of those winds
may have been rain inflated, there were enough vectors in that 
range to assume the system has 30-35 kt winds.  Surface 
observations from Clarion island, located outside of the deep 
convection, measured a peak sustained wind of 23 kt and a gust to 
33 kt, which matched the scatterometer data.  A more recent 
ASCAT-C pass revealed slightly lower winds, but ADT, SATCON, and 
the Dvorak data T-numbers (using a shear pattern) all supported a 
35-kt intensity at around 18Z.  Therefore, the depression is 
upgraded to a 35-kt tropical storm on this advisory.  

The burst of convection that caused the intensification is already 
quickly being shunted westward away from the low-level center due 
to 20-25 kt of easterly shear.  Since the system is forecast to 
remain over warm water during the next couple of days, additional 
bursts of convection are likely to develop and it is nearly 
impossible to forecast if they will have enough organization or 
persistence to maintain the system as a tropical cyclone.  Given 
the shear, the forecast still calls for gradual weakening, but it 
delays the system's transition to a post-tropical cyclone a bit. 

The depression remains within an area of light steering currents and 
the initial motion estimate is 265/2 kt.  The system is only 
forecast to drift westward or west-southwestward during the next day 
or so, before a more pronounced westward or west-northwestward 
motion is expected to begin.  The updated NHC track forecast is in 
best agreement with the TVCE consensus model, which is slightly 
north of the previous official forecast. 


INIT  15/2100Z 17.7N 113.9W   35 KT  40 MPH
 12H  16/0600Z 17.6N 114.1W   30 KT  35 MPH
 24H  16/1800Z 17.6N 114.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  17/0600Z 17.8N 115.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  17/1800Z 18.0N 116.6W   20 KT  25 MPH...POST-TROP/REMNT LOW
 60H  18/0600Z 18.2N 117.6W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  18/1800Z 18.5N 118.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  19/1800Z...DISSIPATED

Forecaster Brown

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