16W生成 - 颱風討論

遠洋來的訪客16W

JTWC第一報

https://i.imgur.com/u1XjVXl.gif

GFS系集
https://i.imgur.com/g6jkqtG.png

EC系集
https://i.imgur.com/Opxf8I4.png


JTWC說明文

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 5-10 KTS
SST: 28-29 CELSIUS
OUTFLOW: MODERATE POLEWARD

FORECAST DISCUSSION: TROPICAL DEPRESSION 16W (SIXTEEN) HAS RAPIDLY
CONSOLIDATED OVER THE PAST 12 HOURS AS IT CROSSED THE DATELINE.
MID-LEVEL DRY AIR AND SOME SHEAR ON THE WESTERN PERIPHERY HAD
CONSTRAINED CONVECTIVE DEVELOPMENT AND HELD THE CONVECTION OFF TO
THE EAST OF THE LLCC DURING THE DAY. AN INFLUX OF MOISTURE AND A
RELAXATION AND REORIENTATION OF THE SHEAR VECTOR, HAS ALLOWED THE
CONVECTION TO EXPAND WESTWARD OVER THE LLCC OVER THE PAST SIX
HOURS. IN THE UPPER LEVELS, CIMSS ANALYSIS AND JTWC 200MB ANALYSIS
REVEALS A SMALL POINT SOURCE OVER TOP OF TD 16W, WHILE A TUTT CELL
LIES ABOUT 700 NM TO THE NW, PROVIDING MODERATE TO STRONG POLEWARD
OUTFLOW ALONG THE EASTERN SIDE OF THE TUTT. THE SYSTEM HAS SLOWED
IN FORWARD SPEED OVER THE PAST TWELVE HOURS AS IT HAS MOVED INTO A
SLIGHTLY WEAKER STEERING ENVIRONMENT IN THE WEAK GRADIENT BETWEEN
LOW TO MID-LEVEL STR CENTER NW OF KAUAI AND ANOTHER LARGER STR
CENTER NEAR 30N 150E. FOR THE DURATION OF THE FORECAST PERIOD, TD
16W IS EXPECTED TO CONTINUE TRACKING GENERALLY WESTWARD, ALONG A
SHALLOW SINE-WAVE TRACK WITH MINOR DEVIATIONS NORTH AND SOUTH OF
DUE WEST, ALONG THE BASE OF THE STR TO THE NORTH. TD 16W IS
FORECAST TO INTENSIFY TO 35 KNOTS WITHIN THE NEXT 12 HOURS, AS THE
TUTT CELL TO THE NORTHWEST MOVES WEST AHEAD OF TD 16W AND REMAINS
IN A FAVORABLE POSITION TO SUPPORT CONTINUED STRONG POLEWARD
OUTFLOW. BY TAU 36 THE TUTT MOVES OUT OF THE AREA AND IS REPLACED
BY RIDGING ALOFT, PUSHING NORTHEASTERLY FLOW OVER TOP OF TD 16W AND
WEAKENING THE OUTFLOW. WHILE THE SYSTEM WILL REMAIN IN RELATIVELY
LOW SHEAR AND OVER VERY WARM WATERS, THE LACK OF OUTFLOW WILL
INHIBIT DEVELOPMENT, LEADING TO WEAKENING THROUGH TAU 72.
THEREAFTER, WEAK EQUATORWARD OUTFLOW WILL OFFSET LOW TO MODERATE
VWS AND WARM SSTS, WITH TD 16W MAINTAINING WEAK MINIMAL TROPICAL
DEPRESSION STRENGTH THROUGH THE REMAINDER OF THE FORECAST.

MODEL DISCUSSION: NUMERICAL TRACK GUIDANCE IS IN GOOD AGREEMENT,
WITH THE MAJORITY OF AVAILABLE TRACKERS CLUSTERED WITHIN A 60 NM
ENVELOPE AT TAU 48, INCREASING TO 135 NM AT TAU 120. NAVGEM IS THE
SOLE OUTLIER, THAT WHILE FOLLOWING THE SAME TRACK SHAPE, IS
DISPLACED WELL NORTH OF THE OTHER TRACKERS. THE JTWC FORECAST LIES
SOUTH OF THE MULTI-MODEL CONSENSUS, AND CLOSELY TRACKS THE GFS
ENSEMBLE WITH HIGH CONFIDENCE. THE INTENSITY GUIDANCE IS MIXED,
WITH THE DECAY SHIPS (GFS AND NAVGEM) INDICATE SIGNIFICANT
STRENGTHENING AFTER TAU 72, WHILE THE COAMPS-TC AND HWRF MODELS
INDICATING MORE MODERATE NEAR-TERM INTENSIFICATION AND A FLAT
TRAJECTORY THEREAFTER. ANALYSIS OF THE SHIPS GUIDANCE INDICATES THE
SHARP INTENSIFICATION IS DUE PRIMARILY TO SST POTENTIAL AND SAMPLE
CHANGE VICE ENVIRONMENTAL PARAMETERS, WHILE THE HWRF AND OTHER
MODELS SEEM TO BE TRACKING THE CHANGES IN THE ENVIRONMENT AND ARE
MORE REALISTIC IN THEIR IMPACTS. HENCE THE JTWC FORECAST TRACKS
CLOSE TO THE CONSENSUS THROUGH TAU 48 WITH MEDIUM CONFIDENCE, AND
BELOW THE CONSENSUS THROUGH THE REMAINDER WITH LOW CONFIDENCE.

FORECAST CONFIDENCE:
TRACK 0 - 72 HR: HIGH
TRACK 72-120 HR: HIGH
INTENSITY 0 - 72 HR: MEDIUM
INTENSITY 72-120 HR: LOW//

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