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Hurricane Calvin Discussion Number  13
NWS National Hurricane Center Miami FL       EP032023
1100 AM HST Fri Jul 14 2023
 
The satellite appearance of Calvin remains impressive this 
afternoon. Its well-defined eye is surrounded by a ring of deep, 
cold convective cloud tops, and visible satellite imagery shows 
healthy upper-level anticyclonic outflow in all quadrants of the 
hurricane. While some drier mid-level air appears to be wrapping 
around the southern and eastern portions of the circulation, 
Calvin's inner core still appears intact at this time. The various 
objective and subjective satellite estimates range from 106-115 kt, 
and the initial intensity is raised to 110 kt for this advisory. 
Some of the initial wind radii values were adjusted based on a 
recently processed 1402 UTC RCM-3 synthetic aperture radar overpass 
over Calvin.
 
Although some small intensity fluctuations cannot be ruled out in 
the near term, Calvin is likely near its peak intensity. The 
hurricane is expected to move over cooler waters tomorrow and into a 
drier, more stable environment through early next week. Calvin 
should also encounter some increased southwesterly vertical wind 
shear later in the forecast period. Therefore, weakening is forecast 
to begin tomorrow and continue into next week. The convective 
structure of Calvin later in the forecast period is a source of 
uncertainty, with the hurricane models (HAFS-A/B) showing more of a 
TC-like structure while the global models (GFS and ECMWF) show it 
almost devoid of convection. For now, the forecast does not show 
Calvin becoming post-tropical until day 5. The latest intensity 
forecast remains on the high end of the guidance envelope through 48 
h, then closely follows the multi-model consensus aids thereafter.
 
The hurricane is moving west-northwestward at 285/14 kt. This
general motion will continue for the next several days as Calvin is
steered by a mid-level ridge that extends westward across the
eastern subtropical Pacific. Once again, the track models are in
good agreement on this scenario. The updated NHC forecast is very
similar to the previous one, but just a bit slower at days 3-5
based on the latest model consensus trends. Calvin is expected to
cross 140W and move into the central Pacific basin by early Monday
morning, then approach the Hawaiian Islands on Tuesday and
Wednesday.
 
 
KEY MESSAGES:
 
1. Calvin is forecast to move across the central Pacific Ocean and
approach the Hawaiian Islands early next week. It is too early to
determine the exact location and magnitude of potential impacts
given uncertainties in the track, intensity, and structure of Calvin
as it approaches the islands. Interests in Hawaii should closely
monitor the latest forecast updates.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  14/2100Z 13.8N 124.6W  110 KT 125 MPH
 12H  15/0600Z 14.3N 126.7W  105 KT 120 MPH
 24H  15/1800Z 15.1N 129.5W  100 KT 115 MPH
 36H  16/0600Z 15.7N 132.4W   90 KT 105 MPH
 48H  16/1800Z 16.3N 135.5W   75 KT  85 MPH
 60H  17/0600Z 16.9N 138.5W   60 KT  70 MPH
 72H  17/1800Z 17.4N 141.9W   50 KT  60 MPH
 96H  18/1800Z 18.3N 149.1W   40 KT  45 MPH
120H  19/1800Z 19.0N 156.0W   35 KT  40 MPH...POST-TROPICAL
 
$$
Forecaster Reinhart
 
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