Halong(24W), Nakri(25W) and Matmo(23W) updates.



Météo974

M974World

WESTERN NORTH PACIFIC


TY HALONG(24W)
WDPN31 PGTW 070300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (HALONG) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 24W (HALONG), LOCATED APPROXIMATELY 560 NM EAST OF
IWO TO, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 08 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE
SYSTEM CONTINUED TO RAPIDLY WEAKEN AS EVIDENCED BY WARMING CLOUD
TOPS AND STRIATIONS AND ELONGATION ALONG THE NORTHEAST FLANK. THE
INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BASED ON A PARTIAL
LOW LEVEL CIRCULATION FEATURE IN THE 062013Z SSMIS MICROWAVE IMAGE.
THE INITIAL INTENSITY OF 105KTS IS BASED ON THE DVORAK ESTIMATES OF
T5.5/102KTS FROM PGTW AND RJTD AND REFLECTS THE RAPID DECAY. TY 24W
IS DRIFTING DEEPER INTO THE MID-LATITUDES AND STRONGER (>20KT)
VERTICAL WIND SHEAR (VWS) THAT IS PARTIALLY OFFSET BY A ROBUST
POLEWARD OUTFLOW INTO THE PREVAILING WESTERLIES. ALONG-TRACK SEA
SURFACE TEMPERATURES (SST) ARE BELOW 28C AND FALLING. OVERALL, THE
ENVIRONMENT IS BECOMING MORE UNFAVORABLE. THE CYCLONE IS TRACKING ON
THE POLEWARD SIDE OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE
EAST.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 24W (HALONG) WILL ACCELERATE AND TRACK ON A MORE
NORTHEASTWARD TRAJECTORY UNDER THE WESTERLY JET WINDS. THE
ENVIRONMENT WILL BECOME MORE UNFAVORABLE WITH INCREASING VWS AND
COOLING SSTS. ADDITIONALLY, BY TAU 24, THE SYSTEM WILL ENTER THE
BAROCLINIC ZONE AND BEGIN EXTRA-TROPICAL TRANSITION (ETT). THESE
COMBINED DYNAMICS WILL CONTRIBUTE TO ITS RAPID DECAY, AND BY TAU 48
WILL BE REDUCED TO A STORM-FORCE COLD CORE LOW WITH AN EXPANSIVE
WIND FIELD AS IT COMPLETES ETT. THE NUMERICAL MODELS ARE IN GOOD
AGREEMENT WITH MODERATE SPREADING, LENDING FAIR CONFIDENCE IN THE
JTWC TRACK FORECAST.//
NNNN

TS NAKRI(25W)
WDPN32 PGTW 070300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 25W (NAKRI)
WARNING NR 06//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
06NOV19. TROPICAL STORM (TS) 25W (NAKRI), LOCATED APPROXIMATELY 221 NM
WEST-SOUTHWEST OF MANILA, PHILIPPINES, HAS TRACKED NORTHEASTWARD AT 03
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) SHOWS AN EXPANSIVE SYSTEM WITH FLARING DEEP CONVECTION AND LARGE
FORMATIVE BANDS FEEDING INTO A CONSOLIDATING LOW LEVEL CIRCULATION
(LLC). THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BY TRACING
THE LOW CLOUD ELEMENTS IN THE MSI LOOP INTO THE LLC AND LINING UP WITH
A RAGGED BUT EXPOSED LLC FEATURE IN THE 062155Z SSMIS MICROWAVE IMAGE.
THE INITIAL INTENSITY OF 45KTS IS BASED ON THE DVORAK CURRENT INTENSITY
ESTIMATES OF T3.0/45KTS FROM RJTD AND PGTW AND REFLECTS THE IMPROVED
STATE. THE SYSTEM IS IN AN OVERALL FAVORABLE ENVIRONMENT WITH ROBUST
POLEWARD OUTFLOW, LIGHT TO MODERATE (15-20KT) VERTICAL WIND SHEAR AND
WARM (29-30C) SST VALUES. THE CYCLONE IS QUASI-STATIONARY (QS) IN THE
SOUTH CHINA SEA (SCS) IN A WEAK STEERING ENVIRONMENT BETWEEN A
SUBTROPICAL RIDGE (STR) TO THE NORTHEAST AND A WEAK STR OVER THE
INDOCHINA PENINSULA TO THE WEST.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 25W WILL REMAIN QS UP TO TAU 24 THEN DRIFT SLOWLY WESTWARD
ACROSS THE SCS AS THE STR TO THE WEST BUILDS, MOVES NORTHWARD, THEN
EXTENDS EASTWARD TO BECOME THE DOMINANT STEERING MECHANISM. THE
FAVORABLE ENVIRONMENT WILL FUEL A GRADUAL INTENSIFICATION TO A PEAK OF
65KTS BY TAU 72 AS THE SYSTEM APPROACHES CENTRAL VIETNAM.
C. BEYOND TAU 72, TS NAKRI WILL CONTINUE WESTWARD UNDER THE
AFOREMENTIONED STR EXTENSION, MAKING LANDFALL OVER CENTRAL VIETNAM JUST
BEFORE TAU 96, THEN DRAG ACROSS THE RUGGED INTERIOR. LAND INTERACTION
WILL RAPIDLY ERODE THE SYSTEM TOWARD DISSIPATION BY TAU 120. NUMERICAL
MODELS ARE IN TIGHT AGREEMENT WITH THE FORECAST TRACK; HOWEVER, THERE
ARE SIGNIFICANT DIFFERENCES IN THE FORECAST ALONG-TRACK SPEED. THIS,
PLUS THE UNCERTAINTY ASSOCIATED WITH THE QS MOTION, LEND LOW CONFIDENCE
IN THE JTWC TRACK FORECAST.//
NNNN

NORTH INDIAN

TS MATMO(23W)
REMARKS:
070300Z POSITION NEAR 14.8N 89.9E.
07NOV19. TROPICAL STORM 23W (MATMO), LOCATED APPROXIMATELY 479 NM
SOUTH-SOUTHWEST OF CHITTAGONG, HAS TRACKED NORTHWARD AT 06 KNOTS
OVER THE PAST SIX HOURS. ANIMATED HIGH RESOLUTION VISIBLE IMAGERY
AND ENHANCED INFRARED IMAGERY DEPICT A RAPIDLY INTENSIFYING SYSTEM
WITH PERSISTENT DEEP CONVECTION OBSCURING THE LOW LEVEL CIRCULATION
CENTER (LLCC). A DEVELOPING EYE FEATURE HAS BECOME EVIDENT OVER THE
PAST HOUR IN THE EIR BD ENHANCEMENT. THE INITIAL POSITION IS PLACED
WITH MODERATE CONFIDENCE BASED ON A 062237Z SSMIS 37 GHZ MICROWAVE
IMAGE WHICH DEPICTED A RELATIVELY BROAD LLCC WITH DEEP CONVECTION
MAINLY LIMITED TO THE WESTERN SIDE OF THE LLCC WRAPPING INTO THE
ASSESSED CENTER. THE INITIAL INTENSITY HAS BEEN INCREASED TO 50
KNOTS WITH HIGH CONFIDENCE. WHILE PGTW AND DEMS DVORAK CURRENT
INTENSITY ESTIMATES WERE T2.5 (35 KNOTS), KNES REPORTED A T4.0 (65
KNOTS). IN LIGHT OF THIS, A SATELLITE CONSENSUS ESTIMATE OF 57 KNOTS
AT 061532Z AND THE DEVELOPMENT OF A POTENTIAL EYE FEATURE, THE
INITIAL INTENSITY HAS BEEN INCREASED SIGNIFICANTLY. TS 23W LIES IN A
FAVORABLE ENVIRONMENT WITH WARM SSTS NEAR 29 CELSIUS, ROBUST
DIVERGENT POLEWARD OUTFLOW AND MODERATE (20-25 KNOTS) VWS. THE VWS
VECTOR IS VERY CLOSE TO BEING IN PHASE WITH THE STORM MOTION, SO NET
SHEAR IS MUCH LOWER THAN THE ENVIRONMENTAL SHEAR WOULD INDICATE, ALL
OF WHICH SUPPORTS FURTHER NEAR-TERM INTENSIFICATION. TS 23W IS
FORECAST TO CONTINUE TRACKING NORTH-NORTHWESTWARD THROUGH TAU 48
ALONG THE WESTERN PERIPHERY OF A DEEP STR CENTERED OVER NORTHERN
THAILAND. AFTER TAU 48, THE SYSTEM WILL ROUND THE RIDGE AXIS AND
SHIFT TO A MORE NORTHEASTWARD TRACK THROUGH TAU 120. BY TAU 96, AS
THE SYSTEM BEGINS TO WEAKEN, STEERING WILL SHIFT TO THE LOWER LEVEL
FLOW AND TS 23W WILL SLOW SIGNIFICANTLY WHILE TURNING EASTWARD IN
THE EXTREME NORTHERN BAY OF BENGAL. TS 23W IS FORECAST TO CONTINUE
TO RAPIDLY INTENSIFY OVER THE NEXT 36 HOURS, PEAKING AT 85 KNOTS BY
TAU 48. THEREAFTER INCREASING VWS AND DECREASING DIVERGENCE ALOFT
WILL COMBINE WITH MID-LEVEL DRY AIR ENTRAINMENT, TO RAPIDLY WEAKEN
THE SYSTEM BEFORE DISSIPATING OVER THE NORTHERN BAY OF BENGAL BY TAU
120. THERE IS OVERALL STRONG AGREEMENT IN THE MODELS ON THE TRACK OF
TS 23W THROUGH TAU 72. THE NOTABLE OUTLIER BEING THE ECMWF, WHICH  
FAVORS A STRAIGHT NORTHWESTWARD TRACK AND NO RECURVE. THE REMAINDER
OF THE CONSENSUS MEMBERS DIVERGE AFTER TAU 96, AS THE SYSTEM
WEAKENS, WITH GALWEM, NAVGEM AND GFS ENSEMBLE ALL TRACKING THE
SYSTEM INTO EASTERN BANGLADESH, WHILE THE GFS, JGSM AND UKMET
MEMBERS TURN THE SYSTEM BACK TOWARDS THE SOUTH AND KEEP IT IN THE
BAY OF BENGAL THROUGH TAU 120. THE JTWC TRACK LIES JUST WEST OF THE
CONSENSUS THROUGH MOST OF THE FORECAST AND JUST AHEAD AND NORTH AT
TAU 120. DUE TO THE UNCERTAINTY IN THE TRACK BEYOND TAU 72, THERE IS
OVERALL LOW CONFIDENCE IN OFFICIAL TRACK FORECAST. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 070000Z IS 22 FEET. NEXT WARNINGS AT
070900Z, 071500Z, 072100Z AND 080300Z.
//
NNNN

25W: 07/0218UTC
25W: 07/0218UTC

23W: 07/0245UTC
23W: 07/0245UTC

24W: TRACK AND INTENSITY GUIDANCE
24W: TRACK AND INTENSITY GUIDANCE

25W: TRACK AND INTENSITY GUIDANCE
25W: TRACK AND INTENSITY GUIDANCE

23W: TRACK AND INTENSITY GUIDANCE
23W: TRACK AND INTENSITY GUIDANCE

07/00UTC
07/00UTC

07/00UTC
07/00UTC
Rédigé par PATRICK HOAREAU le Jeudi 7 Novembre 2019 à 10:13