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Tropical Storm Cristina Discussion Number   9
NWS National Hurricane Center Miami FL       EP052020
300 PM MDT Wed Jul 08 2020
 
Cristina is having some difficulty this afternoon in maintaining 
deep convection over its center.  Briefly, the low-level center 
became apparent via GOES-16 visible imagery just north of its main 
convective mass.  This exposed center was also confirmed by a 1756Z 
37 GHz color image from the GPM satellite.  

The more-easily-observed center allows for a confident assessment of 
its northwest motion at 11 kt.  Cristina should turn back to the 
west-northwest at about the same rate of forward speed tomorrow as a 
broad mid-level ridge builds north of the tropical storm.  That 
motion should continue for the next few days until Cristina turns to 
the west and accelerates slightly as its remnant low is steered by 
the near-surface trade winds.  The global and hurricane dynamical 
models are in close agreement on this forecast track, which is 
slightly north of the previous advisory due to the more northward 
initial position of Cristina.

The Dvorak classifications from SAB and TAFB not changing at 
18Z as well as the partially exposed center indicate that 
the earlier intensification has temporarily ceased. A 50-kt 
maximum wind remains the current intensity, though the ASCAT-A pass 
and SATCON satellite consensus suggests that this may be somewhat 
generous.  

Conditions are quite conducive for intensification in the short 
term, as SSTs are above 28C, mid-level humidity is near 75 percent, 
and deep tropospheric vertical shear is only 5-10 kt.  However, the 
SSTs are already cooling along the track of Cristina and it should 
pass over the 27C SST isotherm in about 36-48 hours.  After 48 
hours, the thermodynamic components quickly become hostile for 
the system. The statistical and mesoscale hurricane models have 
backed off some more and the peak intensity has been lowered 
slightly compared to the previous advisory.  It does appear that 
the opportunity for Cristina to rapidly intensify is diminishing.  
Cristina is expected to become a remnant low in four to five days, 
once deep convection ceases.

The aforementioned ASCAT-A scatterometer pass confirmed the rather 
small size - 60 nm maximum wind radii in the southeastern quadrant 
- of Cristina this afternoon.  Only a modest increase in size is 
expected over the next couple of days based on the RVCN consensus 
technique.
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  08/2100Z 16.0N 107.7W   50 KT  60 MPH
 12H  09/0600Z 17.0N 109.0W   55 KT  65 MPH
 24H  09/1800Z 18.0N 111.0W   60 KT  70 MPH
 36H  10/0600Z 18.9N 113.0W   65 KT  75 MPH
 48H  10/1800Z 19.8N 115.3W   70 KT  80 MPH
 60H  11/0600Z 20.6N 118.1W   65 KT  75 MPH
 72H  11/1800Z 21.1N 120.8W   55 KT  65 MPH
 96H  12/1800Z 21.5N 126.2W   40 KT  45 MPH
120H  13/1800Z 22.0N 132.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Landsea
 
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