Se formó el 5 de septiembre "cerca" de Legazpi, Filipinas a partir de una baja presión. Con condiciones ambientales óptimas para su intensificación, JMA la upgradeó a depresión tropical. Al día siguiente, mientras se movía hacia Filipinas, la JTWC la ascendió a TS dándole el nombre de Chanthu mientras desarrollaba un CDI super uniforme y muy frío, además de un proto ojo que se podía ver en las imágenes satelitales.
Ayer a la mañana la habían ascendió a tormenta tropical severa y apenas al ratito comenzó un periodo de intensificación rápida extrema, pasando de TTS a un Tifón categoría 4 en pocas horas, todo esto con un ojo de alfiler (Pinhole eye).
Ya mucho más cerca de Filipinas, Chanthu se encontró con cortante del norte, jodiendo un poco el outflow de ese cuadrante y debilitándolo temporalmente. Sin embargo, al rato volvió a intensificarse y alcanzó la categoría 5 con una estructura de libro.
El Pinhole eye mode *apenas* ~9km. Para comparar, Wilma (2005) tuvo el Pinhole eye mas pequeño del planeta, con apenas 3km (si mal no recuerdo).
SUMMARY:
INITIAL POSITION: 15.6N 131.3E
INITIAL INTENSITY: 140 KTS
GEOGRAPHIC REFERENCE: 683 NM SOUTH-SOUTHEAST OF KADENA AB
MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 10 KTS
SIGNIFICANT WAVE HEIGHT: 38 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) INDICATES THAT SUPER
TYPHOON CHANTHU HAS CONTINUED TO INTENSIFY OVER THE PAST SIX HOURS,
WITH A VERY COMPACT CORE OF INTENSE CONVECTION WRAPPING INTO A 5NM
PINHOLE EYE. THERE IS HIGH CONFIDENCE IN THE INITIAL POSITION BASED
ON THE PINHOLE EYE AND AN EXTRAPOLATION OF A 080433Z AMSR2 89GHZ
MICROWAVE IMAGE WHICH SHOWED THE PINHOLE EYE SURROUNDED BY A CORE
OF INTENSE CONVECTION AS WELL A MOAT REGION AND ANOTHER BAND OF
STRONG CONVECTION WHICH IS LIKELY THE FIRST SIGN OF A DEVELOPING
SECONDARY EYEWALL. AN EYEWALL REPLACEMENT CYCLE (EWRC) IS EXPECTED
TO BEGIN IMMINENTLY. OBJECTIVE DVORAK ESTIMATES ARE STRUGGLING TO
PROPERLY ASSESS THE INTENSITY OF STY 19W DUE TO EXTREMELY SMALL
EYE, THE ADT AT TIMES SWITCHING TO EMBEDDED CENTER TECHNIQUE AS IT
STRUGGLES TO MAINTAIN TRACK ON THE EYE. SUBJECTIVE ESTIMATES ARE
ALSO STRUGGLING TO PROVIDE CONSISTENT AND ACCURATE INTENSITY
ESTIMATES, AS THE RESOLUTION OF AVAILABLE INFRARED IMAGERY IS SUCH
THAT THE EYE TEMPERATURE MEASUREMENTS ARE SHOWING WILD SWINGS FROM
AS HIGH AS 16C TO AS LOW AS -48C. ADDITIONALLY, A STRONG INNER-CORE
LIGHTNING BURST WAS OBSERVED BETWEEN 0200Z AND 0600Z, WHICH COULD
ALSO SUPPORT A PERIOD OF INTENSIFICATION LEADING UP TO THE 0600Z
INTENSITY. THE INITIAL INTENSITY HAS BEEN INCREASED TO 140 KNOTS
BASED PRIMARILY ON AN EXTRAPOLATION OF AN UNOFFICIAL INTENSITY
ESTIMATE OF T7.0 OBTAINED AT 0310Z USING THE ADT EYE TEMP OF 16C
AND COMPARING THE OVERALL STRUCTURE AT THAT TIME TO THE STRUCTURE
AT 0600Z, WHICH HAD DEPICTED AN EVEN SMALLER EYE AND COLDER CLOUD
TEMPERATURES, THE LIGHTNING BURST AND ASSESSMENT OF THE AMSR2
MICROWAVE DATA. THUS THE LOW CONFIDENCE INTENSITY IS WELL ABOVE ALL
AVAILABLE FIX ESTIMATES.
Ayer cuando la JMA decia que esto era una tormenta tropical severa...
Se intensificó aproximadamente ~90kts en 24hs (30kts en 24hs clasifica para intensificación rápida, esto ya sería "ERI" (extremely rapid intensification).
