[2020] 06W JTWC预报理由翻译帖

MTWP

1. 本产品面向气象专业人员
2. 六小时总结与分析
　　热带低压06W（暂无名）位于嘉手纳空军基地以东约628海里处，过去6小时正以9节的速度向西移动。增强红外线云图动画显示有深对流覆盖在部分裸露且明确的低层环流中心西南侧。因此，初始定位的置信度较高。111235Z的MHS 89GHz微波扫描图像[1]显示其结构非常弱，仅在西南半圆有有离散的深对流。由于111122Z的ASCAT-A图像[2]显示东北半圆有25节风力，而其他位置则有15-20节不等的风力，初始定强仍为25节。虽然06W周围的海温较高（30℃），但是其发展仍然受到中等东风切（20节）阻碍[3]。总降水量图[4]，以及40-45%的500-700毫巴层面上的低相对湿度都显示其所处环境空气较干。06W正沿北侧一道低层副热带高压脊的南缘西移。
3. 预报理由
　　A. 与上一报相比，预报理由没有改变。
　　B. 由于上文中的副高呈西南西-东北东走向，06W预计将转向西南西并接近琉球群岛。其所处环境将持续较为边际，有低至中等的东风切和干空气。（500-700毫巴层面上的相对湿度为45-50%）因此，系统的强度将持续较弱，且预报范围内可能会直接消散。数值模式亦支持JTWC的预报路径，且未来48小时内路径分歧不大，为50海里。未来72小时，模式预报的分歧达到了180海里。JTWC预报路径位于模式平均附近，置信度中等。

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WDPN32 PGTW 111500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 06W (SIX)
WARNING NR 009//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 06W (SIX), LOCATED APPROXIMATELY 628 NM
EAST OF KADENA AB, OKINAWA, HAS TRACKED WESTWARD AT 09 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS
A PARTIALLY-EXPOSED, WELL-DEFINED LOW-LEVEL CIRCULATION WITH FLARING
CONVECTION OVER THE SOUTHWEST QUADRANT. THEREFORE, THERE IS HIGH
CONFIDENCE IN THE INITIAL POSITION. AN 111235Z MHS 89GHZ MICROWAVE
IMAGE INDICATES WEAK, SHALLOW STRUCTURE WITH VERY ISOLATED
CONVECTION DISPLACED TO THE SOUTHWEST. THE INITIAL INTENSITY REMAINS
ASSESSED AT 25 KNOTS BASED ON AN 111122Z ASCAT-A IMAGE SHOWING 25
KNOT WINDS OVER THE NORTHEAST QUADRANT AND 15 TO 20 KNOTS ELSEWHERE.
DESPITE FAVORABLE SST (NEAR 30C), TD 06W CONTINUES TO STRUGGLE DUE
TO PERSISTENT, MODERATE (20 KNOTS) EASTERLY VERTICAL WIND SHEAR
(VWS) AND DRY AIR ENTRAINMENT AS INDICATED IN TOTAL PRECIPITABLE
WATER IMAGERY AND LOW 700-500MB RH VALUES OF 40-45%. TD 06W IS
TRACKING WESTWARD UNDER THE SOUTHERN PERIPHERY OF THE LOW-LEVEL
SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. DUE TO THE WSW-ENE ORIENTATION OF THE LOW-LEVEL STR, TD 06W IS
FORECAST TO GRADUALLY TURN WEST-SOUTHWESTWARD AS IT APPROACHES THE
RYUKYU ISLANDS. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO REMAIN
MARGINAL WITH LOW TO MODERATE EAST-NORTHEASTERLY VWS AND DRY AIR
ENTRAINMENT (700-500MB RH VALUES OF 45-50%), THEREFORE, THE SYSTEM
SHOULD REMAIN SHALLOW AND WEAK WITH SOME POTENTIAL FOR DISSIPATION
DURING THE FORECAST PERIOD. NUMERICAL MODEL GUIDANCE SUPPORTS THE
JTWC FORECAST TRACK AND REMAINS IN FAIR AGREEMENT WITH MINOR
VARIATIONS IN TRACK ORIENTATION THROUGH TAU 48. MODEL SPREAD AT TAU
48 IS 50NM. AFTER TAU 48, MODEL SOLUTIONS DIVERGE WITH A 180NM
SPREAD IN SOLUTIONS AT TAU 72. THE JTWC FORECAST TRACK IS POSITIONED
CLOSE TO THE MULTI-MODEL CONSENSUS WITH MODERATE CONFIDENCE.//
NNNN

MTWP

1. 本产品面向气象专业人员
2. 六小时总结与分析
　　热带低压06W（暂无名）位于嘉手纳空军基地以东约531海里处，过去6小时正以16节的速度向西移动。增强红外线云图动画显示有深对流覆盖在部分裸露且明确的低层环流中心西侧。因此，初始定位的置信度较高。111648Z的AMSR2 89GHz微波扫描图像[1]显示中心南侧和西侧有点状深对流分布。根据当前T1.5的德法分析和之前的ASCAT数据，初始强度仍为25节。虽然系统所处的海温较高（接近30℃）且赤向流出较强[2]，但是其发展受到中等东风切（15-20节）阻碍[3]。40-45%的500-700毫巴层面上的低相对湿度亦导致系统难以发展。06W正沿北侧一道低层副热带高压脊的南缘西移。
3. 预报理由
　　A. 与上一报相比，预报理由没有改变。
　　B. 由于上文中的副高呈西南西-东北东走向，06W预计将向西南西移动并接近琉球群岛。未来12小时内，它可能将再度增强至巅峰强度30节。不过，由于所处环境将持续较为边际，有低至中等的东风切，06W仍然会比较弱。数值模式未来48小时内的预报路径一致，而未来72小时的分歧不小。GFS集合预报与其他模式差距很大，未来24小时内预报的南分量更大。未来48小时后，模式预报的分歧将从50海里增大到180海里。JTWC预报路径位于模式平均附近，因此置信度中等。

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WDPN32 PGTW 112100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 06W (SIX) WARNING NR
010//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 06W (SIX), LOCATED APPROXIMATELY 531 NM EAST
OF KADENA AB, OKINAWA, HAS TRACKED WESTWARD AT 16 KNOTS (KTS) OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A
PARTIALLY-EXPOSED, WELL-DEFINED LOW LEVEL CIRCULATION CENTER (LLCC) WITH
FLARING DEEP CONVECTION IN THE WESTERN SEMICIRCLE, LEADING TO HIGH
CONFIDENCE IN THE INITIAL POSITION. AN 111648Z AMSR2 89 GHZ MICROWAVE
IMAGE SHOWS ISOLATED POCKETS OF DEEP CONVECTION LOCATED TO THE SOUTH AND
WEST OF THE DEFINED LLCC. THE INITIAL INTENSITY REMAINS ASSESSED AT 25
KTS BASED ON A DVORAK CURRENT INTENSITY ESTIMATE OF T1.5 (25 KTS) AND
PREVIOUS ASCAT DATA. FAVORABLE SST (NEAR 30 CELSIUS) AND FAIR
EQUATORWARD OUTFLOW ARE OFFSET BY PERSISTENT, MODERATE (15-20 KT)
EASTERLY VERTICAL WIND SHEAR (VWS). ADDITIONALLY, LOW 700-500 MB
RELATIVE HUMIDITY VALUES OF 40-45% ARE CAUSING THE SYSTEM TO CONTINUE TO
STRUGGLE. TD 06W IS TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF A
LOW LEVEL SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC
REASONING MESSAGE.
   B. DUE TO THE WSW-ENE ORIENTATION OF THE LOW-LEVEL STR, TD 06W IS
FORECAST TO TRACK WEST-SOUTHWESTWARD AS IT NEARS THE RYUKYU ISLANDS.
THERE IS POTENTIAL FOR SLIGHT INTENSIFICATION TO A PEAK INTENSITY OF 30
KTS THROUGH TAU 12. HOWEVER, TD 06W IS EXPECTED TO REMAIN SHALLOW AND
RELATIVELY WEAK DUE TO A CONTINUED MARGINAL ENVIRONMENT OF LOW TO
MODERATE EAST-NORTHEASTERLY VWS. NUMERICAL MODELS ARE IN GOOD AGREEMENT
THROUGH TAU 48 AND THEN FAIR AGREEMENT THROUGH TAU 72. THE SOLE OUTLIER,
THE GFS ENSEMBLE SOLUTION, TRACKS FURTHER TO THE SOUTH AFTER TAU 24 THAN
THE MAJORITY OF THE OTHER SOLUTIONS. AFTER TAU 48, THE MODEL SOLUTIONS
BEGIN TO DIVERGE AND CROSS-TRACK SPREAD INCREASES FROM 50NM TO 180NM BY
TAU 72. THEREFORE, THERE IS MODERATE CONFIDENCE IN THE JTWC FORECAST
TRACK WHICH IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS.//
NNNN

MTWP

1. 本产品面向气象专业人员
2. 六小时总结与分析
　　热带低压06W（暂无名）位于嘉手纳空军基地以东约473海里处，过去6小时正以10节的速度向西南西移动。多光谱云图（MSI）动画显示有零星的深对流覆盖在明确的低层环流中心（LLCC）上。因此，初始定位的置信度较高。120102Z的ASCAT-B图像[1]显示LLCC北侧有若干25-29节的风旗，而东侧和南侧风力较弱。根据JTWC和JMA T1.5的德法分析和上述的ASCAT数据，初始强度为25节，置信度高。系统当前处在持续东风切[2]、干空气（总降水量图上可见），但高海温、赤向流出[3]良好的边际环境中。另外，40-45%的500-700毫巴层面上的低相对湿度亦导致系统难以发展。06W正沿北侧一道西南西-东北东走向的低层副热带高压脊的南缘向西南西移动。
3. 预报理由
　　A. 与上一报相比，预报理由没有改变。
　　B. 由于上文中的副高呈西南西-东北东走向，06W预计将向西南西，然后向西移动并接近琉球群岛。未来36小时后，它将转而向西北西移动。总体而言，06W所处环境将持续较为边际，有干空气、低相对湿度和低至中等的东风切。因此，06W仍然会比较弱，并会在未来72小时内消散。数值模式在长预报时段内分歧不小。GFS集合预报仍然预报的南分量偏大，而NAVGAM预报的北分量偏大。JTWC预报路径位于模式平均附近，因此置信度中等。

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WDPN32 PGTW 120300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 06W (SIX) WARNING NR
011//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 06W (SIX), LOCATED APPROXIMATELY 473 NM EAST
OF KADENA AB, OKINAWA, HAS TRACKED WEST-SOUTHWESTWARD AT 10 KNOTS (KTS)
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
REVEALS POCKETS OF CONVECTION OBSCURING A WELL-DEFINED LOW LEVEL
CIRCULATION CENTER (LLCC), LENDING GOOD CONFIDENCE TO THE INITIAL
POSITION. A 120102Z ASCAT-B IMAGE DEPICTS A SWATH OF 25-29 KT WIND BARBS
TO THE NORTH OF THE LLCC WITH WEAKER WINDS TO THE EAST AND SOUTH.
THEREFORE, THE INITIAL INTENSITY OF 25 KTS IS BASED ON THE
AFOREMENTIONED ASCAT AND DVORAK CURRENT INTENSITY ESTIMATES OF T1.5 (25
KTS) BY PGTW/RJTD WITH GOOD CONFIDENCE. PERSISTENT EASTERLY VERTICAL
WIND SHEAR (VWS) AND DRY AIR ENTRAINMENT SEEN IN TOTAL PRECIPITABLE
WATER IMAGERY OFFSET THE WARM (NEAR 30 CELSIUS) SEA SURFACE TEMPERATURES
AND EQUATORWARD OUTFLOW, PLACING TD 06W IN A MARGINALLY FAVORABLE
ENVIRONMENT. ADDITIONALLY, LOW 700-500MB RELATIVE HUMIDITY VALUES OF 40-
45% ARE CAUSING THE SYSTEM TO STRUGGLE. TD 06W IS TRACKING WEST-
SOUTHWESTWARD UNDER THE STEERING INFLUENCE OF A LOW LEVEL SUBTROPICAL
RIDGE (STR) ORIENTED WSW-ENE.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC
REASONING MESSAGE.
   B. DUE TO THE WSW-ENE ORIENTATION OF THE LOW-LEVEL STR, TD 06W IS
EXPECTED TO TRACK WEST-SOUTHWESTWARD THROUGH TAU 12 THEN TURN WESTWARD
AS IT APPROACHES THE RYUKYU ISLANDS. BY TAU 36, THE SYSTEM WILL SHIFT TO
A WEST-NORTHWESTWARD TRACK FOR THE REMAINDER OF THE FORECAST PERIOD.
OVERALL, TD 06W IS FORECAST TO TRANSIT THROUGH A MARGINALLY FAVORABLE
ENVIRONMENT OF LOW TO MODERATE EAST-NORTHEASTERLY VWS. COMBINED WITH
CONTINUED DRY AIR ENTRAINMENT AND LOW RELATIVE HUMIDITY VALUES, TD 06W
SHOULD REMAIN SHALLOW AND RELATIVELY WEAK WITH DISSIPATION EXPECTED BY
TAU 72, IF NOT SOONER. NUMERICAL MODELS REMAIN IN FAIR AGREEMENT WITH
CROSS-TRACK SPREAD INCREASING IN THE LATER TAUS AS THE SYSTEM
DISSIPATES. THE GFS ENSEMBLE REMAINS THE OUTLIER TO THE SOUTH AND IS
OFFSET BY THE NORTHERLY OUTLIER, NAVGEM. THUS, THE JTWC FORECAST TRACK
IS PLACED ALONG THE MULTI-MODEL CONSENSUS WITH MODERATE CONFIDENCE.//
NNNN

MTWP

1. 本产品面向气象专业人员
2. 六小时总结与分析
　　热带低压06W（暂无名）位于嘉手纳空军基地以东约411海里处，过去6小时正以11节的速度向西南西移动。多光谱云图动画显示裸露的低层云线卷绕进一宽阔且不规则的中心。120646Z的SSMIS 91GHz微波图像[1]显示西侧和西南侧半圆有离散的对流塔，但是总体的对流结构仍然较弱。最近的ASCAT和SSMIS的风场数据显示系统风场不对称，其中只有西北侧有20-25节风力。它们亦显示出系统中心正逐渐变得宽阔，这表明系统正在减弱。不过，根据当前T1.0-1.5（对应25节）的德法分析和上述的ASCAT数据，初始强度仍为25节。系统仍然嵌匿在副高间广阔的东风带中，其东南侧有一TUTT，并处在低至中等的风切（15-20节）、弱分流的干空气环境中。[2][3]06W正沿西北-北侧一道西南西-东北东走向的低层副热带高压脊的南缘向西南西移动。
3. 预报理由
　　A. 与上一报相比，预报理由没有改变。
　　B. 由于上文中的副高呈西南西-东北东走向，06W预计在未来24小时内将向西南西移动。随着它接近琉球群岛，由于副高的形状，它将转而向西、然后向西北西移动。总体而言，06W所处环境将持续较为边际，相对湿度低（700-500毫巴层面相对湿度为50-55%）且东风切低至中等。因此，06W仍然会比较弱，并在预报范围内随时会消散。48小时内数值模式预报分歧不大，但是未来36小时到48小时的分歧从50海里增大到了110海里。JTWC预报路径位于模式平均附近，因此置信度中等。

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WDPN32 PGTW 120900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 06W (SIX) WARNING
NR 012//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 06W (SIX), LOCATED APPROXIMATELY 411 NM
EAST OF KADENA AB, OKINAWA, HAS TRACKED WEST-SOUTHWESTWARD AT 11
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS EXPOSED LOW-LEVEL CLOUD LINES WRAPPING INTO A BROAD,
RAGGED CENTER. A 120646Z SSMIS 91GHZ MICROWAVE IMAGE SHOWS ISOLATED
CONVECTIVE BURSTS OVER THE WEST AND SOUTHWEST QUADRANTS BUT OVERALL
WEAK CONVECTIVE STRUCTURE. RECENT ASCAT IMAGERY AND THE SSMIS WIND
PRODUCT INDICATE A HIGHLY ASYMMETRIC WIND FIELD WITH A PATCH OF 20-
25 KNOT WINDS OVER THE NORTHWEST QUADRANT AND A BROADENING CENTER
REFLECTING A GRADUAL WEAKENING TREND. HOWEVER, THE INITIAL INTENSITY
IS HELD AT 25 KNOTS BASED ON THE ASCAT DATA AND DVORAK CURRENT
INTENSITY ESTIMATES OF 1.0-1.5 (25 KNOTS). THE SYSTEM REMAINS
EMBEDDED WITHIN AN EXPANSIVE REGION OF ENHANCED EASTERLIES BETWEEN
THE UPPER-LEVEL RIDGE AND A TUTT CELL TO THE SOUTHEAST WITH LOW TO
MODERATE (15 TO 20 KNOTS) VERTICAL WIND SHEAR, DRY AIR ENTRAINMENT
AND WEAK DIFFLUENCE. TD 06W IS TRACKING WEST-SOUTHWESTWARD UNDER THE
STEERING INFLUENCE OF A LOW-LEVEL SUBTROPICAL RIDGE (STR) POSITIONED
TO THE NORTH AND NORTHWEST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. DUE TO THE WSW-ENE ORIENTATION OF THE LOW-LEVEL STR, TD 06W IS
FORECAST TO CONTINUE TRACKING WEST-SOUTHWESTWARD THROUGH TAU 24. AS
IT APPROACHES THE RYUKYU ISLANDS, THE SYSTEM SHOULD TURN WESTWARD TO
WEST-NORTHWESTWARD AS IT TRACKS ALONG THE SOUTHWEST PERIPHERY OF THE
STR. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO REMAIN MARGINAL WITH
LOW TO MODERATE VWS AND DRY AIR ENTRAINMENT (700-500MB RH VALUES OF
50-55%), THEREFORE, THE SYSTEM SHOULD REMAIN SHALLOW AND WEAK WITH
SOME POTENTIAL FOR DISSIPATION DURING THE FORECAST PERIOD. NUMERICAL
MODEL GUIDANCE SUPPORTS THE JTWC FORECAST TRACK AND REMAINS IN FAIR
AGREEMENT WITH MINOR VARIATIONS IN TRACK ORIENTATION THROUGH TAU 48.
MODEL SPREAD AT TAU 36 TO 48 RANGES FROM 50 TO 110NM, THEREFORE, THE
JTWC FORECAST TRACK IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS
WITH MODERATE CONFIDENCE.//
NNNN

renzhetegong

1.以下内容面向专业气象人员。
2.过去6小时系统概况与分析：     
       热带低压06W，目前位于日本冲绳嘉手纳空军基地东南东方向349海里处，过去6小时以11节的速度向西南西方向移动。增强型红外卫星云图动画[1]显示此系统的低层环流部分裸露，且深对流主要覆盖在西侧。12日12时14分（UTC）的MHS 89GHz微波图像[2]揭示有杂乱的对流在宽阔而不明确的中心西侧爆发。12日11时01分（UTC）的ASCAT-A图像[3]展现了一个高度不对称的风场，系统的西象限上有一小块25~30节风区，同时，系统的发散中心正趋向缓慢减弱。根据风场的整体情况与PGTW当前T1.5（25节）的德沃夏克分析法分析值，我们仍将初始强度定为25节。系统依然镶嵌在副高间宽阔的强烈东风带[4]中，其东南侧有一条TUTT，并处于夹带中低强度（15~20节）的垂直风切与干空气的弱辐散环境下。[5][6]受到北面及西北面的副热带高压脊（STR）低层影响，热带低压06W正朝着西南西方向前进。
3.预报理由：
     A.自上个预报理由信息发布以来，对本系统的预报理念没有任何变化。
     B.由于低层副高脊的西南西-东北东走向，预计未来12小时内热带低压06W将维持西南西方向行进。临近琉球群岛后，它将沿着副高西南边缘前进，从而会转为西向、而后是西北西方向移动。预计环境状况将保持临界状态：垂直风切属中低值且大气干燥（700-500hPa层面的相对湿度为50~55%）[6]。因此，06W仍将较弱，并有可能在预报期内消散。多家数值预报模型对路径预测达成了高度共识，36小时内仅有微小偏差，这为JTWC的路径预报提供支持。数值对未来36小时的路径预测只有40海里的分歧，而JTWC的预测路径接近多个数值模式的平均[6]，故具有高置信度。


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WDPN32 PGTW 121500MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 06W (SIX) WARNING NR 013//

RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 06W (SIX), LOCATED APPROXIMATELY 349 NM EAST-SOUTHEAST OF KADENA AB, OKINAWA, HAS TRACKED WEST- SOUTHWESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION WITH FLARING DEEP CONVECTION OVER THE WESTERN SEMICIRCLE. A 121214Z MHS 89GHZ COMPOSITE MICROWAVE IMAGE SHOWS DISORGANIZED CONVECTIVE BURSTS OVER THE WESTERN SEMICIRCLE WITH A WEAKLY DEFINED, BROAD CENTER. A 121101Z ASCAT-A IMAGE DEPICTS A HIGHLY ASYMMETRIC WIND FIELD WITH A SMALL AREA OF 25-30 KNOT WINDS OVER THE WEST QUADRANT AND A BROADENING CENTER REFLECTING A GRADUAL WEAKENING TREND. THE INITIAL INTENSITY IS HELD AT 25 KNOTS BASED ON THE OVERALL WIND STRUCTURE AND A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF 1.5 (25 KNOTS). THE SYSTEM REMAINS EMBEDDED WITHIN AN EXPANSIVE REGION OF ENHANCED EASTERLIES BETWEEN THE UPPER-LEVEL RIDGE AND A TUTT CELL TO THE SOUTHEAST WITH LOW TO MODERATE (15 TO 20 KNOTS) VERTICAL WIND SHEAR, DRY AIR ENTRAINMENT AND WEAK DIFFLUENCE. TD 06W IS TRACKING WEST-SOUTHWESTWARD UNDER THE STEERING INFLUENCE OF A LOW-LEVEL SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH AND NORTHWEST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. DUE TO THE WSW-ENE ORIENTATION OF THE LOW-LEVEL STR, TD 06W IS FORECAST TO CONTINUE TRACKING WEST-SOUTHWESTWARD THROUGH TAU 12. AS IT APPROACHES THE RYUKYU ISLANDS, THE SYSTEM SHOULD TURN WESTWARD TO WEST-NORTHWESTWARD AS IT TRACKS ALONG THE SOUTHWEST PERIPHERY OF THE STR. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO REMAIN MARGINAL WITH LOW TO MODERATE VWS AND DRY AIR ENTRAINMENT (700-500MB RH VALUES OF 50-55%), THEREFORE, THE SYSTEM SHOULD REMAIN SHALLOW AND WEAK WITH SOME POTENTIAL FOR DISSIPATION DURING THE FORECAST PERIOD. NUMERICAL MODEL GUIDANCE SUPPORTS THE JTWC FORECAST TRACK AND IS IN TIGHT AGREEMENT WITH MINOR VARIATIONS IN TRACK ORIENTATION THROUGH TAU 36. MODEL SPREAD AT TAU 36 IS 40NM, THEREFORE, THE JTWC FORECAST TRACK IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.//

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MTWP

1. 本产品面向气象专业人员
2. 6小时总结与分析
　　热带低压06W（无名）位于嘉手纳空军基地东南东约299海里处，过去6小时以11节的速度向西南西移动。增强红外线云图动画显示低层环流（LLC）上空有深对流建立，正好覆盖住了LLC的位置。由于最近没有微波图像来协助确定LLC的位置，初始定位置信度低。因为JTWC最新的德法分析为T1.5（对应25节），初始强度仍然定位25节。系统仍然处在高层脊和东南侧TUTT之间的广阔东风带中的低至中等风切（15-20节）[1]、弱分流[2]的干空气环境中。06W受北-西北侧一道低层副热带高压脊引导而向西南西移动。
3. 预报理由
　　A. 与上一报相比，预报原理没有改变。
　　B. 预计未来12小时内，06W的移动方向仍会有较小的南分量。当它靠近琉球群岛之时，由于此时其沿副高西南缘行进，它将转而向西移动。环境条件将持续较为边际：风切较低而空气较干（700-500毫巴层面的相对湿度为50-55%）。因此，系统将维持较弱的强度，并在未来36小时内消散。数值模式在未来12小时内预报一致。除了GFS预报未来12小时后系统会转向西南，数值模式在未来36小时内预报也一致。因此，靠近模式平均路径的JTWC预报路径置信度较高。

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WDPN32 PGTW 122100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 06W (SIX) WARNING
NR 014//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 06W (SIX), LOCATED APPROXIMATELY 299 NM
EAST-SOUTHEAST OF KADENA AB, OKINAWA, JAPAN HAS TRACKED WEST-
SOUTHWESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY DEPICTS DEEP CONVECTION BUILDING OVER THE
LOW-LEVEL CIRCULATION (LLC), OBSCURING THE EXACT LOCATION OF THE
LLC. THERE ARE NO RECENT MICROWAVE IMAGES AVAILABLE TO ASSIST IN
DETERMINING THE EXACT LOCATION OF THE LLC, LEADING TO LOW CONFIDENCE
IN THE INITIAL POSITION. THE INITIAL INTENSITY IS HELD AT 25 KNOTS
BASED ON A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF 1.5 (25 KNOTS).
THE SYSTEM REMAINS EMBEDDED WITHIN AN EXPANSIVE REGION OF ENHANCED
EASTERLIES BETWEEN THE UPPER-LEVEL RIDGE AND A TUTT CELL TO THE
SOUTHEAST WITH LOW TO MODERATE (15 TO 20 KNOTS) VERTICAL WIND SHEAR,
DRY AIR ENTRAINMENT AND WEAK DIFFLUENCE ALOFT. TD 06W IS TRACKING
WEST-SOUTHWESTWARD UNDER THE STEERING INFLUENCE OF A LOW-LEVEL
SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH AND NORTHWEST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TD 06W IS FORECAST TO TRACK WESTWARD WITH A SLIGHT SOUTHERLY
COMPONENT THROUGH TAU 12. AS IT APPROACHES THE RYUKYU ISLANDS, THE
SYSTEM SHOULD TURN WESTWARD AS IT TRACKS ALONG THE SOUTHWEST
PERIPHERY OF THE STR. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO
REMAIN MARGINAL WITH LOW VWS AND DRY AIR ENTRAINMENT (700-500MB RH
VALUES OF 50-55%). THEREFORE, THE SYSTEM SHOULD REMAIN SHALLOW AND
WEAK, LIKELY DISSIPATING BY TAU 36 WITH SOME POTENTIAL FOR
DISSIPATION EARLIER IN THE FORECAST PERIOD. NUMERICAL MODEL GUIDANCE
IS IN TIGHT AGREEMENT THROUGH TAU 12 AND MOST MODELS ARE IN
AGREEMENT THROUGH TAU 36, WITH GFS BEING THE OUTLIER TURNING THE
SYSTEM SOUTHWESTWARD AFTER TAU 12. THEREFORE, THE JTWC FORECAST
TRACK IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH
CONFIDENCE.//
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MTWP

　　热带低压06W（无名）位于嘉手纳空军基地东南东约234海里处，过去6小时以14节的速度向西移动。增强多光谱云图动画显示系统深对流零散且没有低层环流中心（LLCC），正快速消散。另外，130042Z的ASCAT-B图像[1]进一步确定了LLCC已经退化为波。初始强度亦基于该图像，它显示系统最大风力为15节。系统的残余波会在未来12小时内继续西移。

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[1]

TROPICAL DEPRESSION 06W (SIX), LOCATED APPROXIMATELY 234
NM EAST-SOUTHEAST OF KADENA AB, OKINAWA, JAPAN HAS TRACKED
WESTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED
MULTISPECTRAL IMAGERY REVEALS A RAPIDLY DECAYING SYSTEM WITH
SPARSE CONVECTION AND NO LOW LEVEL CIRCULATION CENTER (LLCC).
FURTHERMORE, A 130042Z ASCAT B IMAGE CONFIRMS THE LLCC HAS
DEVOLVED INTO AN OPEN WAVE. INTENSITY IS BASED ON THE 130042Z
ASCAT B IMAGE, WHICH SHOWS A MAXIMUM OF 15 KNOTS. THIS REMNANT
WAVE WILL CONTINUE TO TRACK WESTWARD OVER THE NEXT 12 HOURS.