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Western Pacific: 20W(MINDULLE):rapid intensification next 48h, 21W(DIANMU):final warning//Atlantic:18L(SAM):rapid intensification next 48h,24/03utc




24/00UTC.
24/00UTC.

WESTERN PACIFIC.TS 20W(MINDULLE). WARNING 7 ISSUED AT 24/03UTC

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING.  FORECAST DISCUSSION: TD 20W WILL GENERALLY CONTINUE ON ITS CURRENT TRACK UNDER THE SUBTROPICAL RIDGE(STR) UP TO 96H; AFTERWARD, THE SYSTEM WILL TURN MORE NORTHWARD AS IT BEGINS TO ROUND THE WESTERN EDGE OF THE STR. THE FAVORABLE ENVIRONMENT WILL FUEL GRADUAL THEN RAPID INTENSIFICATION TO A PEAK OF 130KNOTS/CAT 4 BY 72H AS INCREASED POLEWARD OUTFLOW IS ANTICIPATED IN CONJUNCTION WITH INITIAL EXPOSURE TO THE STRONG WESTERLIES AHEAD OF A MIDLATITUDE TROUGH. AFTERWARD, INCREASING VERTICAL WIND SHEAR WILL BEGIN TO WEAKEN THE SYSTEM, DOWN TO 115KNOTS/CAT 4 BY 120H.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TD 20W WILL GENERALLY CONTINUE ON ITS CURRENT TRACK UNDER THE SUBTROPICAL RIDGE(STR) UP TO 96H; AFTERWARD, THE SYSTEM WILL TURN MORE NORTHWARD AS IT BEGINS TO ROUND THE WESTERN EDGE OF THE STR. THE FAVORABLE ENVIRONMENT WILL FUEL GRADUAL THEN RAPID INTENSIFICATION TO A PEAK OF 130KNOTS/CAT 4 BY 72H AS INCREASED POLEWARD OUTFLOW IS ANTICIPATED IN CONJUNCTION WITH INITIAL EXPOSURE TO THE STRONG WESTERLIES AHEAD OF A MIDLATITUDE TROUGH. AFTERWARD, INCREASING VERTICAL WIND SHEAR WILL BEGIN TO WEAKEN THE SYSTEM, DOWN TO 115KNOTS/CAT 4 BY 120H.
2021092012  97N1567E  15
2021092018 102N1555E  15
2021092100 107N1541E  15
2021092106 109N1526E  20
2021092112 109N1517E  20
2021092118 109N1510E  20
2021092200 108N1503E  20
2021092206 110N1495E  20
2021092212 112N1486E  25
2021092218 118N1475E  30
2021092300 123N1460E  30
2021092306 130N1447E  35
2021092312 138N1428E  40
2021092318 141N1418E  45
2021092400 146N1409E  50
NNNN

Western Pacific: 20W(MINDULLE):rapid intensification next 48h, 21W(DIANMU):final warning//Atlantic:18L(SAM):rapid intensification next 48h,24/03utc


SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM CONTINUED TO SLOWLY CONSOLIDATE AS THE CIRCULATION HAS BECOME MORE DEFINED AND FEEDER BANDS HAVE DEEPENED AND WRAPPED TIGHTER INTO THE CENTER. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE EVOLVING CIRCULATION IN THE MSI LOOP. THE INITIAL INTENSITY OF 50 KNOTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE HIGH END OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE SLIGHT IMPROVEMENT IN THE SYSTEM. ENVIRONMENTAL ANALYSIS INDICATES HIGHLY FAVORABLE CONDITIONS WITH LOW VERTICAL WIND SHEAR, STRONG UPPER LEVEL OUTFLOW, AND VERY WARM SSTS IN THE PHILIPPINE SEA. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE DEEP-LAYERED STR TO THE NORTHEAST.
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM CONTINUED TO SLOWLY CONSOLIDATE AS THE CIRCULATION HAS BECOME MORE DEFINED AND FEEDER BANDS HAVE DEEPENED AND WRAPPED TIGHTER INTO THE CENTER. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE EVOLVING CIRCULATION IN THE MSI LOOP. THE INITIAL INTENSITY OF 50 KNOTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE HIGH END OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE SLIGHT IMPROVEMENT IN THE SYSTEM. ENVIRONMENTAL ANALYSIS INDICATES HIGHLY FAVORABLE CONDITIONS WITH LOW VERTICAL WIND SHEAR, STRONG UPPER LEVEL OUTFLOW, AND VERY WARM SSTS IN THE PHILIPPINE SEA. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE DEEP-LAYERED STR TO THE NORTHEAST.


MODEL DISCUSSION: NUMERICAL MODELS ARE IN LOOSE AGREEMENT WITH THE TRACK FORECAST WITH THE SPREAD REACHING 1000 KM BY 120H MAINLY CAUSED BY A TIGHT CLUSTER OF TRACKERS INCLUDING UEMN, EGRR, AND AFUM THAT ARE ON THE EXTREME LEFT MARGIN OF THE MODEL ENVELOPE. IN VIEW OF THIS, THERE IS MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST UP TO 72H AND LOW CONFIDENCE AFTERWARD, PROPORTIONALLY ADJUSTED TO THE RIGHT OF THE MODEL CONSENSUS AFTER 72H TO OFFSET THE LEFT OUTLIERS. CONSEQUENTLY, THERE IS ALSO MEDIUM CONFIDENCE IN THE INTENSITY FORECAST UP TO 72H AND LOW AFTERWARD.
MODEL DISCUSSION: NUMERICAL MODELS ARE IN LOOSE AGREEMENT WITH THE TRACK FORECAST WITH THE SPREAD REACHING 1000 KM BY 120H MAINLY CAUSED BY A TIGHT CLUSTER OF TRACKERS INCLUDING UEMN, EGRR, AND AFUM THAT ARE ON THE EXTREME LEFT MARGIN OF THE MODEL ENVELOPE. IN VIEW OF THIS, THERE IS MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST UP TO 72H AND LOW CONFIDENCE AFTERWARD, PROPORTIONALLY ADJUSTED TO THE RIGHT OF THE MODEL CONSENSUS AFTER 72H TO OFFSET THE LEFT OUTLIERS. CONSEQUENTLY, THERE IS ALSO MEDIUM CONFIDENCE IN THE INTENSITY FORECAST UP TO 72H AND LOW AFTERWARD.


TS 20W(MINDULLE). HWRF AT 24/00UTC. INTENSITY GUIDANCE: 121KNOTS AT +72H.
TS 20W(MINDULLE). HWRF AT 24/00UTC. INTENSITY GUIDANCE: 121KNOTS AT +72H.


WESTERN PACIFIC.TD 21W(DIANMU) WARNING 5/FINAL ISSUED AT 23/15UTC

2121092100 114N1180E  15
2121092106 114N1175E  15
2121092112 114N1169E  15
2121092118 116N1163E  15
2121092200 119N1154E  15
2121092206 123N1143E  20
2121092212 128N1133E  25
2121092218 130N1124E  25
2121092300 135N1112E  30
2121092306 143N1102E  35
2121092312 152N1089E  35
NNNN

24/00UTC.
24/00UTC.


24/00UTC.
24/00UTC.


ATLANTIC. TS 18L(SAM). WARNING 6 ISSUED AT 24/03UTC

CURRENT INTENSITY IS 60KNOTS AND IS FORECAST TO PEAK AT 110KNOTS/CAT 3 BY 26/00UTC.
CURRENT INTENSITY IS 60KNOTS AND IS FORECAST TO PEAK AT 110KNOTS/CAT 3 BY 26/00UTC.
1821091900 103N 115W  15
1821091906 100N 131W  15
1821091912  98N 147W  15
1821091918  96N 163W  15
1821092000  95N 178W  20
1821092006  95N 193W  25
1821092012  93N 210W  25
1821092018  94N 228W  25
1821092100  95N 247W  25
1821092106  95N 261W  25
1821092112  95N 273W  25
1821092118  95N 285W  25
1821092200  96N 296W  25
1821092206  96N 307W  25
1821092212  98N 319W  30
1821092218 100N 331W  30
1821092300 102N 344W  30
1821092306 106N 360W  35
1821092312 108N 376W  45
1821092318 110N 391W  50
1821092400 111N 403W  60

TS 18L(SAM). TRACK AND INTENSITY GUIDANCE.
TS 18L(SAM). TRACK AND INTENSITY GUIDANCE.


24/0030UTC.
24/0030UTC.
Rédigé par PATRICK HOAREAU le Friday, September 24th 2021 à 05:00