WTPZ45 KNHC 271454 RRA

TCDEP5



HURRICANE ROSA DISCUSSION NUMBER  10

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP202018

800 AM PDT THU SEP 27 2018



ROSA IS BECOMING BETTER ORGANIZED.  CONVENTIONAL SATELLITE IMAGERY

SHOW A LARGE AREA OF COLD CLOUD TOPS NEAR THE CENTER, AND THERE IS

A HINT OF AN EYE IN THE FIRST-LIGHT VISIBLE IMAGES.  MICROWAVE

IMAGERY INDICATES THAT THE EYE STRUCTURE UNDERNEATH THE OVERCAST

HAS BECOME BETTER DEFINED, WITH LESS EVIDENCE OF DRY AIR ENTRAINMENT

THAN SEEN YESTERDAY.  THE INITIAL INTENSITY HAS BEEN INCREASED TO

90 KT IN BEST AGREEMENT WITH THE SUBJECTIVE DVORAK ESTIMATE FROM

TAFB AND THE CIMSS ADT TECHNIQUE.  THE HURRICANE CURRENTLY HAS GOOD

OUTFLOW IN ALL DIRECTIONS.



CONDITIONS APPEAR GENERALLY FAVORABLE FOR CONTINUED STRENGTHENING

FOR THE NEXT 24-36 HR, AND THE NEW INTENSITY FORECAST NOW MAKES ROSA

A MAJOR HURRICANE IN 12 H.  IT SHOULD BE NOTED THAT IF THE CURRENT

STRENGTHENING IS THE START OF THE PREVIOUSLY ANTICIPATED RAPID

INTENSIFICATION ROSA COULD GET STRONGER THAN THE CURRENT FORECAST,

WHICH SHOWS A PEAK INTENSITY OF 105 KT NEAR THE UPPER EDGE OF THE

INTENSITY GUIDANCE.  AFTER 36 H, THE FORECAST TRACK TAKES THE

CYCLONE OVER DECREASING SEA SURFACE TEMPERATURES, AND BY THE END OF

THE FORECAST PERIOD IT IS EXPECTED TO ENCOUNTER STRONG SOUTHWESTERLY

VERTICAL SHEAR.  THIS COMBINATION SHOULD CAUSE SIGNIFICANT

WEAKENING, AND ROSA IS EXPECTED TO BE A TROPICAL STORM AS IT

APPROACHES THE BAJA CALIFORNIA PENINSULA NEAR THE END OF THE

FORECAST PERIOD.



THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 270/10.  FOR THE NEXT

12-24 H, THE HURRICANE SHOULD MOVE GENERALLY WESTWARD ON THE SOUTH