Eastern Pacific Basin Tropical Cyclones

Tropical Storm Frank Forecast Discussion


446 
WTPZ42 KNHC 012037
TCDEP2

Tropical Storm Frank Discussion Number  27
NWS National Hurricane Center Miami FL       EP072022
200 PM PDT Mon Aug 01 2022

Frank's convection continues to fade as it maintains its trek over 
cooler waters. In response, both subjective and objective Dvorak 
numbers are decreasing. In addition, we received a direct overhead 
ASCAT-B pass at 1820 UTC, which showed a peak wind retrieval of 
43-kt in the northern semicircle of the storm. Assuming a little 
undersampling from this instrument, the intensity was reduced to 45 
kt this advisory, favoring the lower end of Dvorak estimates.

Frank is still moving northwestward at 310/10 kt. There is little 
change in the track reasoning this cycle. Frank's track should 
gradually bend more poleward as it becomes a shallow vortex and is 
steered by the southerly flow ahead of a deep-layer trough. The 
latest NHC track forecast remains near the consensus aids, and is 
just a touch left of the previous forecast.

Sea surface temperatures under the storm are already down to 22 C
and only cool further along the forecast track. The latest model
output from the GFS, ECMWF, CMC, and HWRF all suggest the remaining
convection will fizzle out over the next 24 hours. The latest
forecast now shows Frank becoming a post-tropical cyclone by that
time-frame. It will take another few days for the large wind
field of Frank to spin down enough for it to open up into a
trough. This is expected to occur by Friday, well offshore 
southeastward of coastal California.


FORECAST POSITIONS AND MAX WINDS

INIT  01/2100Z 22.8N 123.4W   45 KT  50 MPH
 12H  02/0600Z 24.0N 124.5W   40 KT  45 MPH
 24H  02/1800Z 25.5N 125.8W   35 KT  40 MPH...POST-TROPICAL
 36H  03/0600Z 27.4N 126.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  03/1800Z 29.4N 127.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  04/0600Z 31.4N 127.3W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  04/1800Z 33.0N 127.1W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  05/1800Z...DISSIPATED

$$
Forecaster Papin




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