SIO: DJOUNGOU - Post-Tropical

[cycloneye]

SH, 90, 2024020906, , BEST, 0, 105S, 672E, 15, 1009, DB, 0, , 0, 0, 0, 0, 1012, 250, 0, 0, 0, S, 0, , 0, 0, INVEST

https://www.ssd.noaa.gov/PS/TROP/DATA/A ... 902024.dat

[cycloneye]

- North-East of the Mascarenes: there is a low risk (10 to 30%) of formation of a moderate tropical storm by tomorrow, moderate (30 to 60%) on Friday and strong (greater than 60%) this weekend. The system should then move towards the South-East, moving away from inhabited lands.

[cycloneye]

THE AREA OF CONVECTION (INVEST 90S) PREVIOUSLY LOCATED NEAR
13.4S 66.8E IS NOW LOCATED NEAR 13.6S 66.1E, APPROXIMATELY 531 NM
SOUTHWEST OF DIEGO GARCIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) DEPICTS A FAIRLY SMALL PARTIALLY EXPOSED LOW LEVEL CIRCULATION
CENTER WITH DEEP CONVECTION FLARING ON THE EASTERN PERIPHERY OF THE
SYSTEM. DESPITE A FAIRLY WEAK 850MB VORTICITY SIGNATURE, ENVIRONMENTAL
ANALYSIS REVEALS FAVORABLE CONDITIONS FOR FURTHER DEVELOPMENT OF INVEST
90S WITH GOOD POLEWARD OUTFLOW ALOFT, LOW (10-15KT) VWS, AND WARM (29-30
C) SST. GLOBAL MODELS ARE IN GENERAL AGREEMENT THAT 90S WILL CONTINUE ON
AN EASTWARD TRACK THROUGH THE SUBSIDENT ENVIRONMENT TO FINALLY GET MORE
OF A CHIMNEY EFFECT GOING IN ITS FAVOR BEYOND TAU 72, AND CONSOLIDATE
AND STRENGTHEN MORE. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18
TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS LOW.

[cycloneye]

THE AREA OF CONVECTION (INVEST 90S) PREVIOUSLY LOCATED NEAR
13.6S 66.1E IS NOW LOCATED NEAR 14.8S 65.1E, APPROXIMATELY 299 NM NORTH-
NORTHEAST OF PORT MATHURIN, MAURITIUS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY (EIR) DEPICTS A CONSOLIDATING LOW LEVEL CIRCULATION
(LLC) WITH THE DEEP CONVECTION BECOMING MORE PERSISTENT. ENVIRONMENTAL
ANALYSIS REVEALS FAVORABLE CONDITIONS FOR DEVELOPMENT DUE TO GOOD
POLEWARD OUTFLOW ALOFT, LOW (5-10KT) VERTICAL WIND SHEAR (VWS), AND WARM
(29-30C) SEA SURFACE TEMPERATURE (SST). FURTHERMORE, A POINT SOURCE
DIRECTLY OVER THE ANALYZED POSITION REVEALS SUPPORTIVE, ROBUST RADIAL
DIVERGENCE ALOFT. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 90S WILL
SLOWLY TRACK EASTWARD INTO AN AREA OF INCREASED SURFACE LEVEL
CONVERGENCE BY TAU 72 AND RAPIDLY CONSOLIDATE. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. 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 MEDIUM.

[cycloneye]

FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
140 NM EITHER SIDE OF A LINE FROM 14.5S 63.1E TO 16.7S 68.8E
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 25 TO 30 KNOTS. METSAT
IMAGERY AT 150300Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 15.0S 64.2E. THE SYSTEM IS MOVING SOUTHWESTWARD AT 03 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 90S) PREVIOUSLY LOCATED NEAR
14.8S 65.1E IS NOW LOCATED NEAR 15.0S 64.2E, APPROXIMATELY 285 NM NORTH
OF PORT MATHURIN, MAURITIUS. RECENT ENHANCED INFRARED SATELLITE IMAGERY
(EIR) DEPICTS EXTENSIVE DEEP CONVECTION PERSISTING OVER THE CENTRAL AND
EASTERN PORTION OF A LEVEL CIRCULATION (LLC) EVIDENT IN 150134Z SSMIS
IMAGERY. ENVIRONMENTAL ANALYSIS INDICATES FAVORABLE CONDITIONS FOR
FURTHER DEVELOPMENT, INCLUDING LOW VERTICAL WIND SHEAR (5-10 KTS),
FAVORABLE POLEWARD OUTFLOW ALOFT, AND VERY WARM (28-29C) SEA SURFACE
TEMPERATURES. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THAT
INVEST 90S WILL CONTINUE TO DEVELOP AND INTENSIFY OVER THE NEXT 24 HOURS
AS IT TURNS EASTWARD ALONG THE SOUTHERN PERIPHERY OF NEAR EQUATORIAL
RIDGING TO THE NORTH. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT
25 TO 30 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.

[cycloneye]

TROPICAL DEPRESSION number 6

Maximum winds (averaged over 10 minutes) estimated at sea: 55 km/h.

Maximum gusts estimated at sea: 75 km/h.

Estimated pressure at center: 1001 hPa.

Position on February 15 at 4 p.m. local: 15.3 South / 64.2 East.

Distance from the Reunion coast: 1095 km to sector: NORTHEAST

Distance from Mayotte: 2070 km to sector: EAST

Movement: SOUTH-SOUTH-EAST, at 9 km/h.

System information:

- The tropical depression system n°06-20232024, located east of Saint-Brandon, has been monitored by the CMRS of Réunion since the previous night through regular bulletins.

- This tropical depression system began its cyclogenesis phase northeast of the Mascarenes, in a favorable environment for its development and is located approximately 450 km north of Rodrigues Island.

- Over the next 48 hours, this system should evolve in an east-southeast direction while gradually strengthening to the probable stage of a strong tropical storm, and should over the next weekend curve its trajectory into direction of the southeast, accelerating its course.

- Due to its modest size, the meteor should have a limited impact on Rodrigues Island. However, occasionally, degraded sea conditions are possible at the end of the week, off this island.

[cycloneye]

MODERATE TROPICAL STORM number 6

(DJOUNGOU)

Maximum winds (averaged over 10 minutes) estimated at sea: 65 km/h.

Maximum gusts estimated at sea: 95 km/h.

Estimated pressure at center: 1001 hPa.

Position on February 15 at 10 p.m. local: 15.3 South / 65.0 East.

Distance from the Reunion coast: 1165 km to sector: EAST-NORTH-EAST

Distance from Mayotte: 2160 km to sector: EAST

Travel: EST, 15 km/h.

System information:

- Moderate tropical storm Djoungou was named by the Mauritian meteorological services at 1800Z. It is located off the east coast of Saint-Brandon. It is monitored by the CMRS of Réunion through regular bulletins.

- This tropical storm began its cyclogenesis phase northeast of the Mascarenes, in a favorable environment for its development and is located approximately 520 km north of Rodrigues Island.

- Over the next 48 hours, this system should evolve in an east-southeast direction while gradually strengthening until it becomes a probable strong tropical storm at first. Then over the next weekend it should curve its trajectory towards the southeast, accelerating its course, and possibly strengthen further to reach the tropical cyclone stage.

- Due to its modest size, the meteor should have a limited impact on Rodrigues Island. However, occasionally, degraded sea conditions are possible at the end of the week, off this island.

[cycloneye]

JTWC has it as a 100kt cat 3 at peak intensity, but it will not be a threat to any island.

[Hurricane2022]

JTWC has it as a 100kt cat 3 at peak intensity, but it will not be a threat to any island.

https://i.imgur.com/wHvsZmU.jpeg

Well then I'll be rooting for this to become a Category 5 super cyclone

FORECAST DISCUSSION: TROPICAL CYCLONE 13S (DJOUNGOU) APPEARS TO BE
RAPIDLY FORMING A COMPACT INNER CORE STRUCTURE WITHIN AN
ENVIRONMENT CONSISTING OF VERY WARM SEA SURFACE TEMPERATURES, LIGHT
SHEAR, AND DEEP MOISTURE. THESE CONDITIONS ARE EXPECTED TO PERSIST
FOR THE NEXT 36-48 HOURS AS DJOUNGOU TRACKS EASTWARD, GUIDED BY A
MID-LATITUDE LONGWAVE TROUGH WELL TO THE SOUTHEAST. ADDITIONALLY,
DJOUNGOU WILL PASS OVER AN EDDY OF LOCALLY HIGHER OCEAN HEAT
CONTENT VALUES (IN EXCESS OF 60 KJ PER SQUARE CM) DURING THE 24-48
HOUR PERIOD. THIS ENVIRONMENT IS LIKELY TO FACILITATE RAPID
INTENSIFICATION (RI) IN THE NEAR TERM, AND STATISTICAL RI AIDS
SUPPORT THIS WITH 40-60 PERCENT PROBABILITIES OF RI DURING THE NEXT
48 HOURS. THE JTWC INTENSITY FORECAST BRINGS DJOUNGOU TO TYPHOON
INTENSITY (65 KT) IN 24 HOURS AND TO 100 KT IN 48 HOURS. PEAK
INTENSITY IS LIKELY TO OCCUR BETWEEN 48 AND 72 HOURS AS THE CYCLONE
APPROACHES THE SUBTROPICAL JET, BENEFITING FROM CONSTRUCTIVE
INTERFERENCE WITH A 130 KT JET STREAK TO THE SOUTHEAST THAT WILL
PROVIDE SIGNIFICANT UPPER-LEVEL DIVERGENT FORCING OVER THE CYCLONE.
BY 72 HOURS, VERTICAL SHEAR WILL INCREASE DRAMATICALLY AS DJOUNGOU
NEARS THE JET AXIS, AND THE CYCLONE'S ACCELERATING SOUTHEASTWARD
MOTION ALONG THE JET WILL BRING IT OVER COOLER WATERS, ULTIMATELY
LOWER THAN 26 DEGREES CELSIUS BY 120 HOURS, LEADING TO RAPID
WEAKENING.

[cycloneye]

An eye feature is trying to form.

[cycloneye]

MODERATE TROPICAL STORM number 6

(DJOUNGOU)

Maximum winds (averaged over 10 minutes) estimated at sea: 75 km/h.

Maximum gusts estimated at sea: 100 km/h.

Estimated pressure at center: 998 hPa.

Position on February 16 at 4 a.m. local time: 15.7 South / 65.6 East.

Distance from the Reunion coast: 1190 km to sector: EAST-NORTH-EAST

Distance from Mayotte: 2220 km to sector: EAST

Movement: SOUTH-EAST, at 11 km/h.

System information:

- Moderate tropical storm Djoungou was named by the Mauritian meteorological services at 1800Z. It is located off the east coast of Saint-Brandon. It is monitored by the CMRS of Réunion through regular bulletins.

- This tropical storm began its cyclogenesis phase northeast of the Mascarenes, in a favorable environment for its development and is located approximately 510 km north-northeast of Rodrigues Island.

- Over the next few hours, this system should evolve in an east-southeast direction while gradually strengthening until it will initially become a strong tropical storm. Then over the next weekend it should accelerate its course, and could strengthen further slightly to reach the stage of a tropical cyclone.

- Due to its modest size, the meteor should have a limited impact on Rodrigues Island. However, occasionally, degraded sea conditions are possible at the end of the week, off this island.

[cycloneye]

MODERATE TROPICAL STORM number 6

(DJOUNGOU)

Maximum winds (averaged over 10 minutes) estimated at sea: 75 km/h.

Maximum gusts estimated at sea: 100 km/h.

Estimated pressure at center: 997 hPa.

Position on February 16 at 10 a.m. local: 16.1 South / 65.7 East.

Distance from the Reunion coast: 1180 km to sector: EAST-NORTH-EAST

Distance from Mayotte: 2240 km to sector: EAST-SOUTH-EAST

Movement: SOUTH-EAST, at 6 km/h.

System information:

- Moderate tropical storm DJOUNGOU continues to develop more than 400 km northeast of Rodrigues

- It is expected to strengthen significantly in the next 24 hours and could reach tropical cyclone stage this weekend. However, this intensification is expected to occur as the system moves eastward away from inhabited land.

[cycloneye]

 https://twitter.com/Sausius_wx/status/1758460413547512020

[cycloneye]

STRONG TROPICAL STORM number 6

(DJOUNGOU)

Maximum winds (averaged over 10 minutes) estimated at sea: 95 km/h.

Maximum gusts estimated at sea: 130 km/h.

Estimated pressure at center: 985 hPa.

Position on February 16 at 10 p.m. local: 16.2 South / 66.6 East.

Distance from the Reunion coast: 1255 km to sector: EAST-NORTH-EAST

Distance from Mayotte: 2330 km to sector: EAST-SOUTH-EAST

Travel: EST, at 9 km/h.

System information:

- Strong tropical storm DJOUNGOU continues to develop more than 400 km northeast of Rodrigues

- It is currently intensifying and this intensification could be rapid over the next 24 to 36 hours. However, this intensification is expected to occur as the system moves eastward away fro

[Sciencerocks]

 https://twitter.com/VortixWx/status/1758620167649611977

[cycloneye]

STRONG TROPICAL STORM number 6

(DJOUNGOU)

Maximum winds (averaged over 10 minutes) estimated at sea: 100 km/h.

Maximum gusts estimated at sea: 150 km/h.

Estimated pressure at center: 983 hPa.

Position on February 17 at 4 a.m. local time: 16.0 South / 67.5 East.

Distance from the Reunion coast: 1355 km to sector: EAST-NORTH-EAST

Distance from Mayotte: 2430 km to sector: EAST-SOUTH-EAST

Travel: EST, at 13 km/h.

System information:

- Strong tropical storm DJOUNGOU continues to develop more than 400 km northeast of Rodrigues

- It is currently intensifying and this intensification could be rapid over the next 24 to 36 hours. However, this intensification is expected to occur as the system moves eastward away from populated land.

- It could then reach the stage of intense tropical cyclone this weekend.

[cycloneye]

JTWC has it as a 100kt cat 3 at peak intensity, but it will not be a threat to any island.

https://i.imgur.com/wHvsZmU.jpeg

Well then I'll be rooting for this to become a Category 5 super cyclone

FORECAST DISCUSSION: TROPICAL CYCLONE 13S (DJOUNGOU) APPEARS TO BE
RAPIDLY FORMING A COMPACT INNER CORE STRUCTURE WITHIN AN
ENVIRONMENT CONSISTING OF VERY WARM SEA SURFACE TEMPERATURES, LIGHT
SHEAR, AND DEEP MOISTURE. THESE CONDITIONS ARE EXPECTED TO PERSIST
FOR THE NEXT 36-48 HOURS AS DJOUNGOU TRACKS EASTWARD, GUIDED BY A
MID-LATITUDE LONGWAVE TROUGH WELL TO THE SOUTHEAST. ADDITIONALLY,
DJOUNGOU WILL PASS OVER AN EDDY OF LOCALLY HIGHER OCEAN HEAT
CONTENT VALUES (IN EXCESS OF 60 KJ PER SQUARE CM) DURING THE 24-48
HOUR PERIOD. THIS ENVIRONMENT IS LIKELY TO FACILITATE RAPID
INTENSIFICATION (RI) IN THE NEAR TERM, AND STATISTICAL RI AIDS
SUPPORT THIS WITH 40-60 PERCENT PROBABILITIES OF RI DURING THE NEXT
48 HOURS. THE JTWC INTENSITY FORECAST BRINGS DJOUNGOU TO TYPHOON
INTENSITY (65 KT) IN 24 HOURS AND TO 100 KT IN 48 HOURS. PEAK
INTENSITY IS LIKELY TO OCCUR BETWEEN 48 AND 72 HOURS AS THE CYCLONE
APPROACHES THE SUBTROPICAL JET, BENEFITING FROM CONSTRUCTIVE
INTERFERENCE WITH A 130 KT JET STREAK TO THE SOUTHEAST THAT WILL
PROVIDE SIGNIFICANT UPPER-LEVEL DIVERGENT FORCING OVER THE CYCLONE.
BY 72 HOURS, VERTICAL SHEAR WILL INCREASE DRAMATICALLY AS DJOUNGOU
NEARS THE JET AXIS, AND THE CYCLONE'S ACCELERATING SOUTHEASTWARD
MOTION ALONG THE JET WILL BRING IT OVER COOLER WATERS, ULTIMATELY
LOWER THAN 26 DEGREES CELSIUS BY 120 HOURS, LEADING TO RAPID
WEAKENING.

Peak is 115kt.

WDXS31 PGTW 162100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 13S (DJOUNGOU) WARNING
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 16.2S 66.6E
INITIAL INTENSITY: 65 KTS
GEOGRAPHIC REFERENCE: 647 NM SOUTH-SOUTHWEST OF DIEGO GARCIA
MOVEMENT PAST 6 HOURS: EASTWARD AT 05 KTS
SIGNIFICANT WAVE HEIGHT: 23 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 13S (DJOUNGOU) CONTINUES TO STEADILY
CONSOLIDATE AND INTENSIFY AS IT TRACKS SLOWLY EASTWARD. THE LATEST
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
COMPACT INNER CORE OF CONVECTION WHICH HAS OVER THE PAST FEW HOURS
RAPIDLY DEVELOPED INTO A SMALL CENTRAL DENSE OVERCAST (CDO), WITH
OVERSHOOTING TOPS APPROACHING -90C. A 161637Z GMI COLOR ENHANCED
37GHZ MICROWAVE IMAGE DEPICTED A WELL-DEFINED MICROWAVE EYE
FEATURE, SURROUNDED BY A CYAN RING, AND FRAGMENTED SPIRAL BANDS OF
CONVECTION WRAPPING INTO THE INNER CORE. THE INITIAL POSITION IS
ASSESSED WITH HIGH CONFIDENCE BASED ON AN EXTRAPOLATION OF THE
MICROWAVE EYE SUPPORTED BY A WARM SPOT IN THE GOES-IO BD-ENHANCED
IMAGE FROM 161745Z. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON A T4.0 CURRENT INTENSITY ESTIMATE FROM KNES AND
A DVORAK DATA-T ESTIMATE OF T4.0 FROM PGTW. ANALYSIS REVEALS A VERY
FAVORABLE ENVIRONMENT WITH LOW (0-5 KNOTS) WEST-NORTHWEST SHEAR,
WARM SSTS, RELATIVELY HIGH, OHC AND GOOD RADIAL OUTFLOW ENHANCED BY
A ROBUST POLEWARD OUTFLOW CHANNEL INTO THE DIVERGENT QUADRANT OF A
120 KNOT JET MAX TO THE SOUTHEAST. WHILE OVERALL SHEAR IS QUITE
LOW, MID-LEVEL SHEAR IS SLIGHTLY HIGHER BASED ON GFS MODEL
SOUNDINGS AND THE PRESENCE OF A SHARP UPSHEAR EDGE OF THE MID-LEVEL
CLOUD DECK. OVER THE PAST 12 HOURS, THE SYSTEM HAS TAKEN A SLOWER,
MORE EASTWARD TRACK THAN ANTICIPATED, LIKELY IN RESPONSE TO THE
ORIENTATION OF THE LOW- TO MID-LEVEL RIDGE TO THE NORTH.

INITIAL WIND RADII BASIS: PERSISTENCE

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A DEEP-LAYER NEAR
EQUATORIAL RIDGE (NER) TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T3.5 - 55 KTS
KNES: T4.0 - 65 KTS
FMEE: T3.5 - 55 KTS
FIMP: T3.5 - 55 KTS
CIMSS ADT: 55 KTS AT 161500Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
VWS: 0-5 KTS
SST: 29-30 CELSIUS
OUTFLOW: STRONG POLEWARD AND EQUATORWARD

ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE PHASE TRANSITION TYPE HAS BEEN
CHANGED FROM EXTRATROPICAL TO SUBTROPICAL AND THE FORECAST HAS BEEN
TRUNCATED TO 96 HOURS.

FORECAST DISCUSSION: TC 13S IS FORECAST TO CONTINUE TRACKING
GENERALLY EAST-SOUTHEASTWARD OVER THE NEXT 12 TO 24 HOURS AS IT
CONTINUES TO STRENGTHEN AND INTENSIFY. AS THE VORTEX EXPANDS, THE
STEERING LEVEL WILL GET STEADILY HIGHER, LEADING TO A MORE
SOUTHEASTWARD TRACK AFTER TAU 24. THE TIGHT GRADIENT BETWEEN THE
NER TO THE NORTH AND A STRONG MID-LATITUDE TROUGH TO THE SOUTH AND
WEST WILL ACCELERATE TC 13S UP TO ABOUT 20 KNOTS BY TAU 72 BEFORE
SLOWING ONCE MORE BY THE END OF THE FORECAST AS IT RUNS INTO A LOW-
TO MID-LEVEL RIDGE LURKING OFF THE WEST COAST OF AUSTRALIA. IN
TERMS OF INTENSITY, THE ENVIRONMENT IS PRIMED FOR RAPID
INTENSIFICATION (RI), WITH HIGHLY FAVORABLE ENVIRONMENTAL
PARAMETERS LINING UP SUPPORT. THE ONLY THING HOLDING THE SYSTEM
BACK AT THE MOMENT IS A BIT OF MID-LEVEL SHEAR, BUT AVAILABLE
GUIDANCE SUGGESTS THIS SHOULD WEAKEN IN THE NEXT 6-12 HOURS. ONCE
THE CONVECTION CAN BEGIN TO WRAP UPSHEAR, THE SYSTEM WILL EMBARK
UPON A PERIOD OF RI, WITH THE FORECAST CALLING FOR A PEAK OF 115
KNOTS BY TAU 36. BUT THE WINDOW FOR RI IS BRIEF AS SHEAR WILL
SHARPLY INCREASE BEGINNING AT TAU 48, INCREASING FURTHER TO NEAR 60
KNOTS BY TAU 72 BRINGING WITH IT A SURGE IN VERY DRY MID-LEVEL AIR.
THE HIGH VWS AND LOW MOISTURE CONTENT WILL CONSPIRE TO DECAPITATE
AND SMOTHER TC 13S BEGINNING AS EARLY AS TAU 48. AS THE SYSTEM IS
EXPECTED TO RETAIN ITS WARM CORE CHARACTERISTICS AND REMAIN OVER
MARGINAL (25-26C) WATERS DURING THIS TIME, IT IS FORECAST TO
UNDERGO SUBTROPICAL TRANSITION (STT) BEGINNING BY TAU 72 AND
POTENTIALLY AS EARLY AS TAU 60. TRANSITION TO A STORM-STRENGTH
SUBTROPICAL LOW IS ANTICIPATED NO LATER THAN TAU 96.

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN VERY GOOD
AGREEMENT IN THE OVERALL TRACK DIRECTION, AS TO BE EXPECTED WITH
SUCH A WELL-STRUCTURED STEERING PATTERN. CROSS-TRACK SPREAD AT TAU
72 IS JUST 150NM BETWEEN THE EGRR, GALWEM AND UKMET ENSEMBLE
MARKING THE NORTHERN EDGE AND THE NAVGEM MARKING THE SOUTHERN EDGE
OF THE GROUPING. THROUGH THE END OF THE FORECAST, THE MODELS REMAIN
IN GOOD CROSS-TRACK AGREEMENT, BUT BEGIN TO SPREAD OUT ALONG-TRACK,
REACHING UP TO 410NM BETWEEN THE GALWEM AND UKMET ENSEMBLE BY TAU
96. THE JTWC FORECAST IS CONSISTENT WITH THE CONSENSUS MEAN
THROUGHOUT THE FORECAST PERIOD WITH HIGH CONFIDENCE. INTENSITY
GUIDANCE IS IN GOOD AGREEMENT THAT THE SYSTEM WILL INTENSIFY FOR
THE NEXT 36 HOURS, THE ONLY QUESTION IS BY HOW MUCH. THE SHIPS
(GFS) IS THE MOST BEARISH, PEAKING THE SYSTEM AT JUST 85 KNOTS,
WHILE THE HAFS-A IS THE MOST BULLISH REACHING 135 KNOTS. THE
COAMPS-TC, HAFS-A, AND HWRF ALL PEAK THE SYSTEM BETWEEN 115-135
KNOTS. ADDITIONALLY, MULTIPLE RI AIDS ARE TRIGGERED WITH THIS RUN,
PROVIDING ADDITIONAL CONFIDENCE TO THE JTWC FORECAST OF RI OF 50
KNOTS IN 36 HOURS. AFTER THE SHORT RUN TO THE PEAK, THE SYSTEM WILL
RAPIDLY WEAKEN THROUGH THE REMAINDER OF THE FORECAST AS IT
UNDERGOES STT.

[cycloneye]

STRONG TROPICAL STORM number 6

(DJOUNGOU)

Maximum winds (averaged over 10 minutes) estimated at sea: 110 km/h.

Maximum gusts estimated at sea: 155 km/h.

Estimated pressure at center: 980 hPa.

Position on February 17 at 10 a.m. local: 16.1 South / 68.3 East.

Distance from the Reunion coast: 1425 km to sector: EAST-NORTH-EAST

Distance from Mayotte: 2520 km to sector: EAST-SOUTH-EAST

Travel: EST, at 17 km/h.

System information:

- The strong tropical storm DJOUNGOU continues to evolve more than 600 km northeast of Rodrigues Island, where its only significant consequence is to generate a degraded sea state.

- The system continues its intensification at a sustained to rapid pace, which should make it reach the tropical cyclone stage this Saturday then possibly an intense tropical cyclone tomorrow Sunday, before weakening at the start of next week while moving away towards the south-east without threatening inhabited land.

[cycloneye]

JTWC has it as a 100kt cat 3 at peak intensity, but it will not be a threat to any island.

https://i.imgur.com/wHvsZmU.jpeg

Well then I'll be rooting for this to become a Category 5 super cyclone

FORECAST DISCUSSION: TROPICAL CYCLONE 13S (DJOUNGOU) APPEARS TO BE
RAPIDLY FORMING A COMPACT INNER CORE STRUCTURE WITHIN AN
ENVIRONMENT CONSISTING OF VERY WARM SEA SURFACE TEMPERATURES, LIGHT
SHEAR, AND DEEP MOISTURE. THESE CONDITIONS ARE EXPECTED TO PERSIST
FOR THE NEXT 36-48 HOURS AS DJOUNGOU TRACKS EASTWARD, GUIDED BY A
MID-LATITUDE LONGWAVE TROUGH WELL TO THE SOUTHEAST. ADDITIONALLY,
DJOUNGOU WILL PASS OVER AN EDDY OF LOCALLY HIGHER OCEAN HEAT
CONTENT VALUES (IN EXCESS OF 60 KJ PER SQUARE CM) DURING THE 24-48
HOUR PERIOD. THIS ENVIRONMENT IS LIKELY TO FACILITATE RAPID
INTENSIFICATION (RI) IN THE NEAR TERM, AND STATISTICAL RI AIDS
SUPPORT THIS WITH 40-60 PERCENT PROBABILITIES OF RI DURING THE NEXT
48 HOURS. THE JTWC INTENSITY FORECAST BRINGS DJOUNGOU TO TYPHOON
INTENSITY (65 KT) IN 24 HOURS AND TO 100 KT IN 48 HOURS. PEAK
INTENSITY IS LIKELY TO OCCUR BETWEEN 48 AND 72 HOURS AS THE CYCLONE
APPROACHES THE SUBTROPICAL JET, BENEFITING FROM CONSTRUCTIVE
INTERFERENCE WITH A 130 KT JET STREAK TO THE SOUTHEAST THAT WILL
PROVIDE SIGNIFICANT UPPER-LEVEL DIVERGENT FORCING OVER THE CYCLONE.
BY 72 HOURS, VERTICAL SHEAR WILL INCREASE DRAMATICALLY AS DJOUNGOU
NEARS THE JET AXIS, AND THE CYCLONE'S ACCELERATING SOUTHEASTWARD
MOTION ALONG THE JET WILL BRING IT OVER COOLER WATERS, ULTIMATELY
LOWER THAN 26 DEGREES CELSIUS BY 120 HOURS, LEADING TO RAPID
WEAKENING.

New peak from JTWC is 105 kt.

WDXS31 PGTW 170900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 13S (DJOUNGOU)
WARNING NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 16.2S 68.9E
INITIAL INTENSITY: 65 KTS
GEOGRAPHIC REFERENCE: 585 NM SOUTH-SOUTHWEST OF DIEGO GARCIA
MOVEMENT PAST 6 HOURS: EASTWARD AT 13 KTS
SIGNIFICANT WAVE HEIGHT: 23 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE (TC) 13S (DJOUNGOU) EXHIBITING PERSISTENT, CENTRALIZED DEEP
CONVECTION PARTIALLY OBSCURING THE LOW LEVEL CIRCULATION CENTER
OVER THE PAST 12 HOURS. A 170419Z MHS 89GHZ MICROWAVE IMAGE REVEALS
A FORMATIVE MICROWAVE EYE CLOSED OFF IN ALL BUT THE SOUTHEASTERN
SECTION WITH SPIRAL BANDING WRAPPING INTO CENTER OF CIRCULATION. AS
NUMERICAL MODELING GUIDANCE SUGGESTS, A RELATIVELY DRY AIR MASS
WEST-SOUTHWEST OF THE LLCC HAS BEGUN TO ENTRAIN THE WESTERN
PERIPHERY OF THE SYSTEM, AS EVIDENCE BY A PARTIAL CLEARING OF
CLOUDS IN THE MIDDLE TO UPPER LAYERS OF THE ATMOSPHERE. DESPITE
THE DRY AIR, HOWEVER, THE ENVIRONMENT IS OVERALL VERY FAVORABLE FOR
INTENSIFICATION TO OCCUR WITH LOW (0-5KTS) VERTICAL WIND SHEAR
(VWS), WARM (29-30C) SEA SURFACE TEMPERATURES (SST), AND
EXCEPTIONAL POLEWARD DIVERGENCE ALOFT. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON A 170511Z METOP-B
SCATTEROMETRY IMAGE. THE INITIAL INTENSITY OF 65 KTS IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON THE AFOREMENTIONED SCATTEROMETRY
DATA AND THE INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA

CURRENT STEERING MECHANISM: NER NORTHEAST OF THE LLCC

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T4.0 - 65 KTS
KNES: T4.0 - 65 KTS
CIMSS ADT: 61 KTS AT 170630Z
CIMSS AIDT: 55 KTS AT 170700Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 0-5 KTS
SST: 29-30 CELSIUS
OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
INITIAL POSITION: MEDIUM
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 13S IS FORECAST TO TRACK ALONG THE
SOUTHWESTERN PERIPHERY OF A NEAR EQUATORIAL RIDGE THROUGHOUT THE
FORECAST INTERVAL. FROM TAU 00 TO TAU 36, THE STEERING INFLUENCE
PRESENTED WILL SLOWLY TURN THE SYSTEM FROM AN EASTWARD (TAU 00)
TRACK TO A SOUTHEASTWARD TRACK (TAU 36). DURING THIS TIME, THE TC IS
FORECAST TO UNDERGO RAPID INTENSIFICATION IN A VERY FAVORABLE
ENVIRONMENT, PEAKING BETWEEN TAU 24 AND TAU 36 AT NEAR 110KTS.
BEGINNING NEAR TAU 36, HIGH (OVER 30KTS) VWS, DECOUPLING OF UPPER
LEVEL DIVERGENCE SUPPORT, FALLING SST (25C BY TAU 96), AND DRY AIR
ENTRAINMENT OF THE CORE VORTEX (TAU 48 TO TAU 96) ARE ANTICIPATED TO
QUICKLY WEAKEN THE SYSTEM. THE TC IS FORECAST TO TRANSITION TO
A SUBTROPICAL SYSTEM BETWEEN TAU 72 AND TAU 96.

MODEL DISCUSSION: GLOBAL NUMERICAL MODEL GUIDANCE IS IN EXCEPTIONAL
AGREEMENT REGARDING THE TRACK AND GOOD AGREEMENT REGARDING TC
INTENSITY. A CROSS-TRACK SPREAD OF JUST 128NM BETWEEN JTWC
CONSENSUS MEMBERS CONTRIBUTES TO THE ASSESSMENT OF HIGH CONFIDENCE
IN TRACK THROUGHOUT THE FORECAST PERIOD. INTENSITY GUIDANCE
PRESENTS A NOTICEABLE AND UNIFORM DROP IN INTENSITY ACROSS THE JTWC
CONSENSUS SINCE THE PREVIOUS WARNING (162100Z). ADDITIONALLY, RAPID
INTENSIFICATION AIDS HAVE DECREASED PROBABILITY OF RI OCCURRENCE,
BUT STILL REMAIN NOTEWORTHY FROM TAU 00 TAO TAU 36 (BETWEEN 50 AND
80 PCT LIKELIHOOD OF RI OCCURRENCE). A 40KTS SPREAD IS OBSERVED
AMONG CONSENSUS MEMBERS BETWEEN TAU 24 AND 36, CONTRIBUTING TO
AN OVERALL INTENSITY FORECAST CONFIDENCE OF MEDIUM.

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