96W
http://www.metoc.navy.mil/jtwc/products/wp9618web.txt
http://www.metoc.navy.mil/jtwc/products/wp9618.gif
WTPN22 PGTW 211300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/210721Z JUL 18//
AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT (WTPN21 PGTW 210730)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
240 NM EITHER SIDE OF A LINE FROM 11.6N 140.8E TO 17.2N 137.9E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 18 TO 23 KNOTS. METSAT
IMAGERY AT 211200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 11.6N 140.5E. THE SYSTEM IS MOVING WESTWARD AT 07 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 96W) PREVIOUSLY LOCATED
NEAR 11.4N 141.1E, IS NOW LOCATED NEAR 11.6N 140.5E, APPROXIMATELY
190 NM NORTHEAST OF YAP. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY SHOWS A LOW LEVEL CIRCULATION WITH PERSISTENT CONVECTION AND
LOW LEVEL BANDING BEGINNING TO WRAP INTO THE CENTER. A 210837Z 91GHZ
SSMIS MICROWAVE IMAGE DEPICTS A LOW LEVEL CIRCULATION WITH
PERSISTENT DEEP CONVECTION LOCATED OVER THE CENTER AND SHALLOW
CONVECTION PRIMARILY TO THE SOUTH AND SOUTHEAST. THE DISTURBANCE IS
CURRENTLY LOCATED IN AN AREA OF EXCELLENT EQUATORWARD DIVERGENCE,
LOW (5-10 KNOTS) VERTICAL WIND SHEAR, AND WARM SEA SURFACE
TEMPERATURES (29-30 CELSIUS). GLOBAL MODELS ARE IN AGREEMENT THAT
THE SYSTEM WILL TRACK IN A NORTHERLY DIRECTION AND INTENSIFY OVER
THE NEXT FEW DAYS. SOME MODELS ARE NOT IN AGREEMENT AS TO THE EXACT
TRACK THE SYSTEM WILL TAKE, SHOWING A NORTH-NORTHWESTERN OR
NORTHWESTERN TRACK, WITH A FEW OUTLIERS TAKING THE SYSTEM TO THE
NORTHEAST. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23
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 HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
221300Z.
4. SEE REF A FOR DETAILS ON A TROPICAL CYCLONE FORMATION ALERT
LOCATED NEAR 20.9N 105.6E.//
NNNN
過去的圖像顯示系統開始有深層對流捲入中心，
此外，系統身處的環境有著極優秀的赤向流出，
極低的垂直風切和29~30度的炎熱海溫，是促使系統繼續發展進而發布TCFA的依據。
全球模式認為系統數天內會向北移動，但其餘部分模式仍不明朗，
呈現北北西至西北預測的同時，亦出現朝向東北移動的少數預測路徑。
==============================================================================
97W
http://www.metoc.navy.mil/jtwc/products/wp9718web.txt
http://www.metoc.navy.mil/jtwc/products/wp9718.gif
WTPN21 PGTW 211700
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/211251Z JUL 18//
AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT (WTPN22 PGTW 211300)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 20.9N 159.4E TO 26.0N 159.4E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 18 TO 23 KNOTS. METSAT
IMAGERY AT 211200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 21.2N 159.3E. THE SYSTEM IS MOVING NORTHEASTWARD AT 06 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED
NEAR 20.3N 159.8E IS NOW LOCATED NEAR 21.2N 153.3E, APPROXIMATELY
430NM WEST-NORTHWEST OF WAKE ISLAND. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY AND A 211050Z 89GHZ AMSU MICROWAVE IMAGE DEPICT A
PARTIALLY EXPOSED LLCC WITH A LARGE MASS OF PERSISTENT DEEP
CONVECTION NORTH AND EAST OF THE CENTER. THE LLCC IS CURRENTLY UNDER
A REGION OF LOW (5-10 KNOT) VWS WITH INCREASING SHEAR VALUES TO THE
NORTHEAST. A POLEWARD OUTFLOW CHANNEL IS CREATING STRONG DIVERGENCE
ALOFT, HOWEVER SOME UL INFLOW FROM THE SOUTHWEST IS STIFLING
CONVECTION ALONG THE SOUTHWEST OF THE SYSTEM. SSTS ARE VERY WARM (28-
30 CELSIUS) IN THE NORTHWEST PACIFIC AND WILL SUPPORT FURTHER
DEVELOPMENT. GLOBAL MODELS ARE IN STRONG AGREEMENT ON TRACK, KEEPING
THE SYSTEM TRAVELLING NORTH OVER THE NEXT FEW DAYS AND REACHING
TROPICAL DEPRESSION STRENGTH BY TAU 24. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 18 TO 23 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 HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
221700Z.
4. SEE REF A FOR DETAILS ON A TROPICAL CYCLONE FORMATION ALERT
LOCATED NEAR 11.6N 140.5E.//
NNNN
AMSU顯示LLCC雖呈現局部外露，但系統北側與東側已經有深對流發展，
系統所處環境垂直風切微弱，惟東北側有加強趨勢，
系統有優秀的極地方向流出，不過西南方向的輻合有些受阻。
大範圍高達28~30度的海表面溫度供應系統持續發展的能量，
全球模式具有高度信心認為系統會向北移動並於7/24前增強為熱帶性低氣壓，
綜合這些資訊而發布TCFA。
==============================================================================
整理一下目前的系統和觀察重點
11W&12W&13W
11W（山神）︰
JTWC-TD JMA-TD CWB-TD
似乎受到季風槽帶動的影響，目前已從越南出海返回北部灣再次增強
雖然一度減弱至LPA（低壓區），
但從各機構目前的預報資訊應該仍會繼續判定為同一系統
路徑方面雖然不受到安比直接影響，但可能受到安比改變駛流配置再度出現大迴轉。
12W（安比）︰
各機構皆評價相當於TS上限至STS下限之強度
路徑已經明朗，做為11W&12W&13W間交互作用的主導者，
接下來的速度是關鍵，近期有加速趨勢。
13W（可能的悟空）︰
JTWC-TD JMA-TD（發GW） CWB-TD（有發展輕颱趨勢）
系統距離台灣的遠近取決於安比的速度，安比速度越快13W將離台灣越近北上，
以貼近石垣島北上為主流，而老J的第3報仍有比前2報西修的趨勢。
96W&97W
數值目前認為此兩系統發生藤原的機率不大，
但若96W往東北跑，似乎會和下一個從菲東季風槽誕生的產物藤原。
有類似和安比一樣從東北到西北大迴轉帶動後續發展的系統跟隨的可能。