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Tropical Storm Cristina Discussion Number  14
NWS National Hurricane Center Miami FL       EP052020
900 PM MDT Thu Jul 09 2020
 
Cristina's satellite presentation has degraded somewhat during the 
past several hours, with deep convection on the wane and some 
evidence of dry air near the center.  Still, microwave data does 
show a large banding pattern with a mid-level core present, 
suggesting there might be more than meets the eye than just 
conventional satellite imagery.  The current intensity of the storm 
is difficult to ascertain, as estimates from generally credible 
techniques range from 45 kt to 77 kt on this package.  It is 
probably best to keep the initial wind speed 60 kt for now, and we 
will see if the intensity becomes more clear overnight.
 
The storm has about a day over marginally warm waters in light 
shear conditions before SSTs begin to cool, and eventually 
more significant dry air is entrained into the inner core.  Thus 
some strengthening is anticipated on Friday, and Cristina should 
start a gradual weakening over the weekend through early next week.  
The cyclone should have a challenging time producing convection over 
sub-23C waters, which happens in about 72 hours, so that is the 
time chosen for post-tropical transition.  This is earlier than the 
previous forecast and best matches a GFS/ECMWF blend.  No 
significant changes were made to the intensity forecast with 
guidance in good agreement at this time.  
 
Christina continues moving west-northwestward at about 10 kt.  
A mid-level ridge centered over the southwestern U.S. is expected 
to strengthen over the next day or so, which should force 
the storm in a similar direction but with a slight increase in 
forward speed. Over the weekend, as the cyclone weakens, a gradual 
turn to the west is expected.  The forecast track is a little slower 
than the previous one at long range, otherwise the track is 
basically an update of the earlier track prediction.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  10/0300Z 18.4N 111.9W   60 KT  70 MPH
 12H  10/1200Z 19.1N 113.5W   65 KT  75 MPH
 24H  11/0000Z 20.1N 116.1W   65 KT  75 MPH
 36H  11/1200Z 20.8N 118.9W   55 KT  65 MPH
 48H  12/0000Z 21.3N 121.7W   45 KT  50 MPH
 60H  12/1200Z 21.6N 124.4W   40 KT  45 MPH
 72H  13/0000Z 21.8N 127.0W   35 KT  40 MPH...POST-TROPICAL
 96H  14/0000Z 22.2N 132.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  15/0000Z 22.5N 138.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Blake
 
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