Typhoon Fengshen and Tropical Depression Kalmaegi: updates at 15/03UTC



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WESTERN NORTH PACIFIC

TY FENGSHEN (26W)
As of 00:00 UTC Nov 15, 2019:

Location: 19.1°N 143.7°E
Maximum Winds: 75 kt ( 140km/h)
Gusts: 90 kt ( 170km/h)

Minimum Central Pressure: 985 mb
CATEGORY US: 1

WDPN31 PGTW 150300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 26W (FENGSHEN)
WARNING NR 015//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 26W (FENGSHEN), LOCATED APPROXIMATELY 263 NM
NORTH-NORTHWEST OF SAIPAN, HAS TRACKED NORTHWESTWARD AT 16 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) DEPICTS A NEWLY FORMED EYE WITH WARMING IN THE CENTER. THE EYE
IN THE MSI LOOP SUPPORTS THE INITIAL POSITION WITH EXCELLENT
CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 75 KNOTS BASED ON
THE NEWLY FORMED EYE, IN LINE WITH RJTD DVORAK CURRENT INTENSITY
ESTIMATES OF T4.5 (77 KTS) AND A 150015Z ADVANCED DVORAK TECHNIQUE
ESTIMATE OF T4.4 (75 KTS). THE PGTW DVORAK ESTIMATE OF T5.0 (90 KTS)
AND A 142147Z SATCON ESTIMATE OF 86 KTS ARE ABOVE THE CURRENT
INTENSITY ESTIMATE, BUT THE SYSTEM WILL TAKE TIME TO SPIN UP THE
TANGENTIAL CIRCULATION. TY 26W IS LOCATED IN AN AREA OF LOW TO
MODERATE (5-10 KNOTS) VERTICAL WIND SHEAR, WARM SEA SURFACE
TEMPERATURES (28-29C) AND MODERATE WESTWARD AND EQUATORWARD
DIFFLUENCE ALOFT. TY 26W IS TRACKING ALONG THE SOUTHWESTERN
PERIPHERY OF A DEEP-LAYERED SUBTROPICAL STEERING RIDGE SITUATED TO
THE NORTH.
3. FORECAST REASONING.
   A.  THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY
FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. WIND RADII WERE
ADJUSTED USING A 142356Z METOP-A BULLSEYE ASCAT PASS.
   B. TY 26W IS FORECAST TO GRADUALLY RECURVE AROUND THE WESTERN
PERIPHERY OF THE BROAD STR AFTER TAU 12. THE TIMING OF THE RECURVE
CONTINUES TO MOVE UP AS MODELS INCREASE THE ALONG-TRACK SPEED. LOW
VERTICAL WIND SHEAR, PASSAGE OVER WARM WATER AND IMPROVING POLEWARD
OUTFLOW AS IT TAPS INTO A PASSING MIDLATITUDE TROUGH TO THE NORTH
WILL LIKELY FUEL STEADY INTENSIFICATION THROUGH TAU 24 WITH A PEAK
INTENSITY OF 95 KNOTS EXPECTED AT TAU 24. AFTER TAU 24, A WEAKENING
TREND WILL BEGIN AS THE SYSTEM SLIDES UNDER UPPER-LEVEL WESTERLY
WINDS AND ENCOUNTERS INCREASING VERTICAL WIND SHEAR AND DRY AIR.
NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THIS OVERALL
SCENARIO THROUGH TAU 48 IN CROSS-TRACK SPREAD, BUT THERE ARE STILL
SIGNIFICANT ALONG-TRACK SPEED DIFFERENCES BETWEEN MODEL SOLUTIONS,
LENDING POOR CONFIDENCE TO THE INITIAL PORTION OF THE TRACK FORECAST.
   C. IN THE EXTENDED FORECAST PERIOD, TY 26W IS EXPECTED TO WEAKEN
QUICKLY UNDER STRONG (40 TO 50 KNOTS) WESTERLY VERTICAL WIND SHEAR.
THE CONVECTION WILL BE SHEARED TO THE NORTHEAST. THE PRIMARY
STEERING INFLUENCE WILL SHIFT TO A LOW-LEVEL HIGH THAT IS FORECAST
TO BUILD TO THE NORTH AFTER TAU 48, STEERING THE REMNANT LOW LEVEL
CIRCULATION OF TY 26W BACK TO THE WEST. NUMERICAL MODELS AGREE WITH
THIS OVERALL FORECAST SCENARIO, BUT VARY IN THEIR DEPICTIONS OF THE
RATE OF WEAKENING AND EXACT TRACK DURING THE EXTENDED PERIOD. NAVGEM
REFLECTS THE QUICKEST TURN TO THE SOUTH. ECMWF, NAVGEM, AND GFS ARE
TO THE INSIDE OF THE MULTI-MODEL CONSENSUS, ALTHOUGH GFS CLOSELY
AGREES WITH THE CONSENSUS ABOUT ALONG-TRACK SPEED. GALWEM HAS
SHIFTED TO BE FASTER THAN THE MULTIMODEL CONSENSUS, BUT IS STILL A
WESTERN OUTLIER. THE JTWC FORECAST TRACK CONTINUES TO SHIFT EASTWARD
DUE TO ACCELERATED ALONG-TRACK MOTION. THERE IS LOW CONFIDENCE IN
THIS PORTION OF THE JTWC FORECAST TRACK DUE TO THE COMPLEX STEERING
ENVIRONMENT AND DIFFERENCES IN TIMING OF THE SOUTHWARD TURN AND
ALONG-TRACK SPEED IN LATER TAUS.//
NNNN


TD KALMAEGI (27W)
As of 00:00 UTC Nov 15, 2019:
Location: 16.6°N 125.1°E
Maximum Winds: 30 kt ( 55km/h)
Gusts: 40 kt ( 75km/h)

Minimum Central Pressure: 1004 mb
WDPN32 PGTW 150300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 27W (KALMAEGI)
WARNING NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION 27W (KALMAEGI),
 LOCATED APPROXIMATELY 266 NM EAST-NORTHEAST OF MANILA, PHILIPPINES,
 HAS TRACKED WEST-NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS.
 ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A LARGE AREA OF
 DISORGANIZED, WEAKENING DEEP CONVECTION DISPLACED FROM AN EXTREMELY
ELONGATED, RAGGED, LOW LEVEL CENTER (LLC). A 142341Z GMI 89GHZ IMAGE
INDICATES SCATTERED, FLARING DEEP CONVECTION OBSCURING A LONG LLC.
THE INITIAL INTENSITY REMAINS ASSESSED AT 30 KNOTS BASED ON THE
CONTINUING SHEAR, WEAK CONVECTION, ELONGATED NATURE OF THE LLC, AND A
 PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T2.0 (30 KTS).
ENVIRONMENTAL ANALYSIS REVEALS A MARGINAL ENVIRONMENT WITH STRONG
POLEWARD AND WESTWARD DIFFLUENCE ALOFT, WARM SST (29C) AND HIGH OCEAN
 HEAT CONTENT VALUES, OFFSET BY HIGH VERTICAL WIND SHEAR (VWS) DUE TO
 OPPOSING LOW LEVEL NORTHEASTERLY SURGE FLOW AND UPPER LEVEL
SOUTHWESTERLIES FEEDING INTO THE SUBTROPICAL JET. TD 27W IS LOCATED
IN A BREAK IN THE SUBTROPICAL RIDGE DUE TO A TROUGH PASSING BY TO THE
 NORTH.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 27W WILL MEANDER WESTWARD TO SOUTHWESTWARD IN THE NEAR TERM
IN A WEAK STEERING ENVIRONMENT, AS A PASSING MIDLATITUDE TROUGH TO
THE NORTH HAS CAUSED A BREAK IN THE LOWER LEVEL SUBTROPICAL STEERING
RIDGE. THE GFS AND ECMWF TRACKS CONTINUE TO SHOW A SHARP SOUTHWARD
JOG AND SLOW ALONG-TRACK MOTION IN THE NEAR TERM. THE JTWC FORECAST
 TRACK HAS SHIFTED FURTHER SOUTH AND WEST, ALTHOUGH IT IS POSITIONED
CLOSE TO THE MULTIMODEL CONSENSUS AND NORTH OF THE GFS, GFS ENSEMBLE,
 AND ECMWF SOLUTIONS. AFTER TAU 48, RIDGING IS EXPECTED TO BUILD TO
THE NORTH OF THE SYSTEM, EXERTING A MORE POWERFUL STEERING INFLUENCE
 AND STEERING IT WEST-NORTHWESTWARD TOWARD LUZON. THE MAJORITY OF
NUMERICAL MODEL GUIDANCE INDICATES A TRACK OVER LUZON, WITH GFS THE
SOUTHERN OUTLIER GOING OVER THE CENTER OF THE ISLAND, AND ECMWF
JUST GLANCING THE NORTHERN TIP. NAVGEM AND THE UKMET MODEL ENSEMBLE
TRACKS ARE EVEN FURTHER TO THE NORTH. HOWEVER, GIVEN THE
DISORGANIZATION OF THIS SYSTEM, EXACTLY WHAT VORTEX CENTER THE MODELS
ARE TRACKING IS DEBATABLE. ADDITIONALLY, GIVEN THE STRONG
NORTHEASTERLY SURFACE SURGE, WHICH 34-KT WINDS ARE ATTRIBUTABLE TO
THE SYSTEM AND WHICH ARE RELATED TO THE TROPICAL CYCLONE IS DIFFICULT
TO DEFINE. WIND RADII HAVE BEEN SET LARGER ON THE NORTHEASTERN SIDE
DUE TO THE SURGE FLOW. BASED ON UNCERTAINTY IN THE CURRENT POSITION
AND THE COMPLEX STEERING ENVIRONMENT, THERE IS LOW CONFIDENCE IN THIS
PORTION OF THE FORECAST TRACK. IN THE NEAR TERM, 27W WILL SLOWLY
INTENSIFY TO A PEAK OF 50 KTS AT TAU 48 DUE TO ENHANCED POLEWARD
OUTFLOW AND THE SYSTEM TRACKING SLOWLY OVER HIGH OCEAN HEAT CONTENT
WATER. HOWEVER, TOTAL INTENSIFICATION WILL BE LIMITED BY HIGH VWS.
   C. AFTER TAU 72, TD 27W IS EXPECTED TO CONTINUE TRACKING WESTWARD
ACROSS LUZON. AS IT WEAKENS, IT WILL BEGIN TO RESPOND TO SURFACE
NORTHEASTERLY SURGE AND TRACK SOUTHWESTWARD INTO THE SOUTH CHINA SEA.
PASSAGE OVER THE MOUNTAINOUS TERRAIN OF LUZON, REDUCED DIVERGENCE
ALOFT AS RIDGING BUILDS TO ITS NORTH, AND COLD, DRY AIR ENTRAINMENT
WILL RESULT IN STEADY WEAKENING. HERE, MOST MODEL GUIDANCE AGREES ON
THE GENERAL SOUTHWESTWARD TRACK, BUT THERE REMAINS SIGNIFICANT CROSS-
TRACK AND ALONG-TRACK UNCERTAINTY. THE JTWC FORECAST INTENSITY IS
BELOW THE MULTIMODEL INTENSITY GUIDANCE, BECAUSE STATISTICAL MODELS
ARE NOT ACCURATELY REFLECTING THE HIGH VERTICAL WIND SHEAR IN THE
AREA, WHICH WILL CONTINUE TO LIMIT INTENSIFICATION. MODEL SPREAD
PERSISTS INTO THE EXTENDED FORECAST PERIOD, LENDING LOW CONFIDENCE TO
THE EXTENDED PORTION OF THE FORECAST TRACK.//
NNNN

 

FORECAST TO PEAK AT TOP CAT2 MAYBE CAT3 WITHIN 24H
FORECAST TO PEAK AT TOP CAT2 MAYBE CAT3 WITHIN 24H

SLOWLY APPROACHING NORTHEAST LUZON AND FORECAST TO INTENSIFY GRADUALLY
SLOWLY APPROACHING NORTHEAST LUZON AND FORECAST TO INTENSIFY GRADUALLY

TY 26W: CLICK TO ANIMATE
TY 26W: CLICK TO ANIMATE

TY 27W: 15/00UTC. FY2G. AB/PH
TY 27W: 15/00UTC. FY2G. AB/PH

TD 27W: 15/00UTC
TD 27W: 15/00UTC

26W: TRACK AND INTENSITY GUIDANCE
26W: TRACK AND INTENSITY GUIDANCE

26W: HWRF: 112KTS AT +36H
26W: HWRF: 112KTS AT +36H

27W: TRACK AND INTENSITY GUIDANCE
27W: TRACK AND INTENSITY GUIDANCE
Rédigé par PATRICK HOAREAU le Vendredi 15 Novembre 2019 à 07:46