W環

一個位於西面裸露的低空中心

ben811018

短暫滯留後將沿著東邊的副熱帶高氣壓邊緣往北進行
因為是從北方槽線割離出來的系統
要發展起來的機會低

周子堯@FB

JMA升格為熱低

Meow

突然就Medium了



AN AREA OF CONVECTION (INVEST 93W) HAS PERSISTED NEAR
26.2N 142.2E, APPROXIMATELY 50 NM SOUTH OF CHICHI-JIMA, JAPAN.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A PARTIALLY-
EXPOSED, DEVELOPING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH LOW-
LEVEL CLOUD LINES WRAPPING INTO A DEFINED CENTER. A 130004Z METOP-A
89GHZ IMAGE SHOWS SHALLOW BANDING WRAPPING INTO A BROAD CENTER WITH
FORMATIVE DEEP CONVECTIVE BANDING OVER THE SOUTHEAST QUADRANT OF THE
LLCC. A 130003Z ASCAT PARTIAL IMAGE SHOWS A DEFINED CIRCULATION WITH
15 TO 20 KNOT GRADIENT WINDS OVER THE NORTHERN PERIPHERY AND 10 TO
15 KNOTS ELSEWHERE. SURFACE OBSERVATIONS FROM IWO-TO AND CHICHI-JIMA
INDICATE 10 TO 15 KNOT WINDS WITH SLP 1006MB TO 1007.5MB AND, MORE
SIGNIFICANTLY, A -3.4MB 24-HOUR PRESSURE FALL AT CHICHI-JIMA (-2MB
AT IWO-TO). OVERALL, THE UPPER-LEVEL ENVIRONMENT IS COMPLEX BUT
FAVORABLE WITH AN UPPER-LEVEL TROUGH TO THE NORTH AIDING IN POLEWARD
OUTFLOW AND TWO UPPER-LEVEL LOWS (EAST AND WEST) ENHANCING OUTFLOW.
ADDITIONALLY, SST VALUES OF 29C ARE FAVORABLE FOR FURTHER
DEVELOPMENT. THE PRIMARY LIMITING FACTOR AT THIS TIME IS DRY AIR
PRESENT OVER THE NORTHWESTERN SEMI-CIRCLE AS DEPICTED IN THE TOTAL
PRECIPITABLE WATER IMAGERY AND THE CHICHI-JIMA (RJAO) SOUNDING,
WHICH SHOWS A VERY DRY ATMOSPHERE ABOVE 500MB. DESPITE THE
SUBTROPICAL ORIGIN AND WEAK SUBTROPICAL INFLUENCES, THE SYSTEM
APPEARS TO BE MAINLY TROPICAL IN NATURE AND IS POSITIONED BETWEEN
TWO NORTH-SOUTH ORIENTED SUBTROPICAL RIDGES. THE GLOBAL MODELS SHOW
A SLOW NORTHWARD TRACK WITH NO SIGNIFICANT DEVELOPMENT, HOWEVER, THE
MODELS GENERALLY STRUGGLE WITH THESE HYBRID SYSTEMS. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS MEDIUM.

Meow

發佈風警報。

WARNING.
TROPICAL DEPRESSION 1006 HPA
AT 25.8N 141.8E OGASAWARA SHOTO MOVING NORTH 06 KNOTS.
POSITION FAIR.
MAX WINDS 30 KNOTS NEAR CENTER.

周子堯@FB

JTWC 1406Z評級降為"Low"，緯度漸高，發展不易。

(1) THE AREA OF CONVECTION (INVEST 93W) PREVIOUSLY LOCATED
NEAR 25.8N 142.2E, IS NOW LOCATED NEAR 29.9N 143.2E, APPROXIMATELY
385 NM SOUTH-SOUTHEAST OF TOKYO, JAPAN. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY SHOWS A FULLY EXPOSED AND ELONGATED LOW LEVEL
CIRCULATION CENTER WITH REMAINING CONVECTION SHEARED TO THE EAST AND
NO LONGER WRAPPING IN. A 140448Z AMSU 89GHZ MICROWAVE IMAGE
CONFIRMS A FULLY EXPOSED LOW LEVEL WITH LIMITED CONVECTION TO THE
NORTH AND EAST OF THE DISTURBANCE. A 132343Z ASCAT PARTIAL PASS
SHOWS A VERY ELONGATED CIRCULATION WITH PRIMARILY 10-20 KNOT WINDS
AROUND THE CENTER AND STRONGER WINDS LOCATED TO THE NORTHEAST, BUT
NOT WRAPPING INTO THE SYSTEM. THE DISTURBANCE IS CURRENTLY LOCATED
IN A MARGINAL ENVIRONMENT DUE TO MODERATE VERTICAL WIND SHEAR (10-20
KNOTS), BUT OFFSET BY GOOD UPPER LEVEL OUTFLOW AND WARM SSTS (26-28
C). GLOBAL MODELS ARE ALL IN AGREEMENT THAT THE DISTURBANCE WILL
CONTINUE TRACKING TO THE NORTH-NORTHEAST, BUT NO LONGER INDICATE
THAT IT WILL CONSOLIDATE INTO A TROPICAL CYCLONE. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS NEAR THE CENTER OF THE
DISTURBANCE. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006
MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS DOWNGRADED TO LOW.