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Tropical Storm Cristina Discussion Number 6
NWS National Hurricane Center Miami FL EP052020
1000 PM CDT Tue Jul 07 2020
Since the previous advisory, Cristina's well-defined low-level
center became briefly exposed for a couple of hours, likely
resulting in a slight spin-down of the vortex. However, deep
convection has recently redeveloped over and southwest of the
center, so the intensity will be held at 40 kt for this advisory,
which is a blend of TAFB and SAB subjective satellite
classifications, and the most recent downward-trending UW-CIMSS ADT
estimate of T2.9/43 kt.
The initial motion estimate is 300/13 kt. There is no significant
change to the previous forecast track or reasoning. The latest NHC
model guidance remains in excellent agreement on Cristina moving
west-northwestward south of a nearly stationary deep-layer
subtropical ridge for the next 5 days. The new NHC forecast track is
a tad north of the previous advisory track, and lies close to the
tightly packed simple and corrected consensus models.
High-resolution GOES-16 visible satellite imagery indicates that
Cristina's center has been moving closer to the center of the
synoptic-scale upper-level anticyclone where the vertical wind shear
should be lower. The recent burst of deep convection near the center
could the beginning stages of more significant strengthening owing
to the lower shear, high mid-level humidity near 80 percent, and
sea-surface temperatures (SSTs) near 29C. Therefore, steady
strengthening is forecast for the next 60 h while the cyclone
remains over warm SSTs, and a period of rapid intensification (RI)
is still possible during the next couple of days. By 72 h and
beyond, however, Cristina will be moving over sub-26 deg C SSTs that
will decrease to about 22C by 120 h, with the much cooler water
inducing steady weakening on days 4-5. The NHC intensity forecast
is similar to the IVCN intensity guidance through 36 hours, and
then is slightly higher than the guidance in order to maintain
continuity with the previous intensity forecast and also due to the
possibility of RI occurring.
FORECAST POSITIONS AND MAX WINDS
INIT 08/0300Z 13.8N 105.3W 40 KT 45 MPH
12H 08/1200Z 14.7N 106.7W 50 KT 60 MPH
24H 09/0000Z 15.9N 108.6W 55 KT 65 MPH
36H 09/1200Z 17.0N 110.4W 65 KT 75 MPH
48H 10/0000Z 17.8N 112.2W 75 KT 85 MPH
60H 10/1200Z 18.8N 114.2W 80 KT 90 MPH
72H 11/0000Z 19.8N 116.5W 80 KT 90 MPH
96H 12/0000Z 21.4N 121.6W 65 KT 75 MPH
120H 13/0000Z 22.1N 127.0W 50 KT 60 MPH
$$
Forecaster Stewart
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