Tropical Storm 'Calvin', a few hundred miles off the Mexican coast, consolidated overnight, and the inner core convection organized sufficiently to form a closed eyewall feature, quite evident on a recent passive microwave imaging overpass.

And animated visible satellite imagery from this morning (as well as the above microwave picture) clearly portrays a moderately strengthening system, with new convective banding features now in evidence in the SW and NE quadrants of the storm.

From the latest NHC Bulletin ...

"THE CONVECTIVE SIGNATURE OF CALVIN HAS IMPROVED AS AN EYE-LIKE FEATURE IS EVIDENT FROM BOTH THE 1136Z SSMI IMAGERY AND THE FIRST VISIBLE IMAGES THIS MORNING. ... WITH IMPROVED SUBSEQUENT ORGANIZATION THE ADVISORY INTENSITY IS SET AT 60 KT."

However, it appears that 'Calvin' is about to peak as a tropical cyclone, as environmental parameters, especially cooler SST's, should significantly inhibit the system beginning in another 12 hours, or so.

"CALVIN HAS A LIMITED TIME FOR FURTHER INTENSIFICATION...AS IT IS ABOUT TO REACH THE COOL SST'S AND STABLE ENVIRONMENT SOUTH OF BAJA CALIFORNIA. SO DESPITE THE MODERATE EASTERLY SHEAR ANTICIPATED TO RELAX OVER THE NEXT FEW DAYS...THE CYCLONE IS PROJECTED TO PEAK IN ABOUT 12 HOURS AS A CATEGORY 1 HURRICANE WITH GRADUAL WEAKENING THEREAFTER."

Tropical Cyclone 'Calvin' is well west of Mexico, and is forecast to track WNW, even further from land, as it steadily weakens in the days ahead.

(Imagery courtesy Navel Research Lab, Monterrey)
...