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Tropical Storm Ivo Discussion Number   5
NWS National Hurricane Center Miami FL       EP102019
900 AM MDT Thu Aug 22 2019

The cyclone continues to gradually improve in organization.
Microwave data show that there is a small eye trying to form beneath
Ivo's small central dense overcast, and satellite intensity
estimates are rising.  Consequently, the initial wind speed is set
to 55 kt, which matches the TAFB/SAB fixes.  Further strengthening
is anticipated in the short term since Ivo has a developing inner
core and is over very warm waters with moderate shear.  The models
are pretty consistent about showing an increase in shear by tomorrow
while the cyclone turns to the northwest.  Thus the intensity
forecast is leveled off at that time, then a slow weakening is
shown beyond 36 h as Ivo begins its inevitable decline over cooler
eastern Pacific waters and in more stable air.  Remnant low status
is anticipated just after 72 h since Ivo will be over 23C or cooler
waters by then.  Little change was made to the previous intensity
forecast except for a small rise at 12 h to account for the recent
initial intensity increase.

Similar to many eastern Pacific cyclones this year, the center has
re-formed a bit to the south in the central dense overcast,
yielding an initial motion of 270/10.  The storm should turn
northwestward tomorrow due to an upper-level trough dropping over
the eastern Pacific south of California, which helps erode a
mid-level ridge over mainland Mexico.  The ridge stays weak through
the weekend, causing Ivo to move north-northwestward until
dissipation.  The eastward model trend at long range continues, so
the NHC forecast is adjusted in that direction. It should be noted
that none of the guidance still show a direct threat to Mexico at
this time.


FORECAST POSITIONS AND MAX WINDS

INIT  22/1500Z 15.7N 113.6W   55 KT  65 MPH
 12H  23/0000Z 16.4N 114.8W   65 KT  75 MPH
 24H  23/1200Z 17.9N 116.0W   65 KT  75 MPH
 36H  24/0000Z 19.5N 116.8W   65 KT  75 MPH
 48H  24/1200Z 21.2N 117.6W   55 KT  65 MPH
 72H  25/1200Z 25.0N 119.5W   40 KT  45 MPH
 96H  26/1200Z 28.0N 121.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  27/1200Z...DISSIPATED

$$
Forecaster Blake

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