Las chances de este sistema suben a HIGH, aunque el GFS no desarrolla muy profundamente a este sistema camino de Japón, si que lo marca como una débil Tormenta Tropical de rápido movimiento. En este mapa, que está sin actualizar, aparece con nivel amarillo.





Veremos en que queda finalmente. No parece que vaya a ser algo destacable ni mucho menos, aunque su aspecto actual es bastante bueno, y más aún teniendo en cuenta la latitud a la que se encuentra.

Se ha definido mejor durante la pasada madrugada, alcanzando según la Marina los 30 kts, por lo que ha sido upgradeada a Depresión Tropical nº 21.

CitarTROPICAL DEPRESSION (TD) 21W (TWENTY-ONE), LOCATED APPROXIMATELY
634 NM SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED WEST-NORTHWESTWARD
AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS A PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION
CENTER (LLCC) WITH DEEP CONVECTIVE BANDING WRAPPING INTO THE
SOUTHEAST QUADRANT OF THE LLCC. A 292305Z SSMIS IMAGE DEPICTS AN
ELONGATED YET WELL-DEFINED LLCC WITH IMPROVED CONVECTIVE
ORGANIZATION OVER THE PAST 12 HOURS, THEREFORE, THERE IS GOOD
CONFIDENCE IN THE INITIAL POSITION. RECENT SCATTEROMETER DATA, ALONG
WITH DVORAK INTENSITY ESTIMATES OF 30 KNOTS, SUPPORTS THE INITIAL
INTENSITY ASSESSMENT OF 30 KNOTS. UPPER-LEVEL ANALYSIS INDICATES A
MARGINAL ENVIRONMENT WITH MODERATE NORTHWESTERLY VERTICAL WIND SHEAR
(VWS), WHICH IS HINDERING DEVELOPMENT OVER THE NORTHWEST QUADRANT OF
THE LLCC. TD 21W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE
SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THIS IS THE FIRST PROGNOSTIC REASONING MESSAGE AND ESTABLISHES
THE FORECAST PHILOSOPHY.
   B. TD 21W IS FORECAST TO TRACK WEST-NORTHWESTWARD ALONG THE
SOUTHWESTERN PERIPHERY OF THE STR THROUGH TAU 24 THEN RE-CURVE
POLEWARD EAST OF JAPAN. AFTER TAU 36, TD 21W IS FORECAST TO
ACCELERATE AHEAD OF A MIDLATITUDE SHORTWAVE TROUGH, WHICH IS
EXPECTED TO DEEPEN OVER JAPAN. TD 21W IS FORECAST TO BEGIN EXTRA-
TROPICAL TRANSITION (ETT) NEAR TAU 48 AS IT BEGINS TO INTERACT WITH
THE MIDLATITUDE WESTERLIES AND SHOULD COMPLETE ETT BY 60 AS IT GAINS
FRONTAL CHARACTERISTICS, ENCOUNTERS STRONG VWS AND BECOMES EMBEDDED
WITHIN THE MIDLATITUDE TROUGH. THE AVAILABLE DYNAMIC MODELS AS WELL
AS THE ENSEMBLE MODELS ARE IN EXCELLENT AGREEMENT, THEREFORE, THERE
IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK, WHICH IS POSITIONED
SLIGHTLY FASTER AND TO THE RIGHT OF THE MULTI-MODEL CONSENSUS AFTER
TAU 36. TD 21W IS FORECAST TO REMAIN WITHIN A MARGINAL ENVIRONMENT
THROUGHOUT THE FORECAST WITH MODEST INTENSIFICATION THROUGH TAU 36
AS POLEWARD OUTFLOW IMPROVES WITH A PEAK INTENSITY OF 40 KNOTS
EXPECTED. AN ADDITIONAL DETRIMENT TO SIGNIFICANT DEVELOPMENT IS A
COOL POOL OF SST LOCATED OVER AND TO THE NORTH OF IWO TO, WHICH
SHOULD SERVE TO FURTHER DAMPEN DEVELOPMENT.

Tropical Depression 21W (Sepat) Warning #02
Issued at 30/0900Z



Con nombre, pero con rango de Depresión. Y poco margen de maniobra técnicamente, antes de escapar a rebufo del jet.

Ha tapado e centro, bien podía ser upgrateada a Tormenta

Up!

TROPICAL STORM 21W (SEPAT)

Con este panorama, poco más dará de si

UPPER-LEVEL
ANALYSIS INDICATES POLEWARD OUTFLOW IS BEGINNING TO INCREASE AHEAD
OF A DIGGING TROUGH OVER JAPAN WHICH IS ALSO INCREASING VERTICAL
WIND SHEAR (VWS) THAT IS NOW ASSESSED AT MODERATE TO HIGH (20 TO 30
KNOTS) LEVELS

Le quedan dos telediarios

TS 21W IS FORECAST TO BEGIN EXTRA-
TROPICAL TRANSITION (ETT) BY TAU 24

La "pre" transición a vista de ojo, ha empezado 

Tropical Storm 21W (Sepat) Warning #09 Final Warning

Curioso, con el último parte, está presentando su mejor aspecto