BONGOYO Moderate Tropical Storm
Second of Season 2020-2021 For
South-West Indian Ocean Basin
The Summer Season 2020-2021 for the South-West Indian Ocean Basin is showing signs of being dynamic. ALICIA, the first one developed rapidly into a Tropical Storm after it was named on Friday 13 November 2020. The Low Pressure located South-East of Diego Garcia evolved at a rapid pace since 03 December, as a Disturbance, Depression and into a Moderate Tropical Storm. It has been named BONGOYO by the Mauritius Meteorological Services (MMS) at 9.00 hours today 07 December 2020.
The Mauritius Meteorological Services issued its Special Weather Bulletin at 9.30 am Monday 07 December 2020, as mentioned below.
{{{Special Weather Bulletin
Mon, Dec 7, 2020
Mauritius Meteorological Services
Tropical Weather Outlook issued at 09.30 hours on Monday 07 December 2020
General
The Mauritius Meteorological Services has been following a shallow low-pressure area far to the northeast of our area of responsibility since last week. This low took some time to develop because it was evolving in an unfavourable environment with strong vertical wind shear...
At first the system moved east-south-east and then as from Friday evening it assumed a south-southwest track. Convective activity near the centre pick up gradually at the start of the weekend, and on Sunday 06 December satellite imageries indicated a curved band pattern developing gradually. The low had intensified into a tropical disturbance.
The tropical disturbance continued to intensify over the night as it moved in a region with weak vertical wind shear and good divergence aloft. At 0400 hours this morning it was already a tropical depression...
At 0900 hours this morning (Monday 07 December 2020) while the tropical depression was located at about 2690 km to the East North East of Mauritius, that is, near latitude 14.6 degrees South and 82.4 degrees East, observations indicate that it has now reached the Moderate Tropical Storm intensity. Therefore, it is being named BONGOYO
The moderate tropical storm is moving in a general west-south-west direction at a speed of about 20 km/h...
Outlook from weather models.
Most numerical models agree to maintain this intensity until tomorrow. Thereafter, Bongoyo will encounter strong wind shear again and it will weaken into a depression. The system will continue to fill up and eventually be entrained in the easterlies...
Weather at Mauritius and Rodrigues
Moderate tropical storm Bongoyo will not directly influence weather at Mauritius. Few clouds associated with the remnant of Bongoyo are likely to give few showers at Rodrigues by the end of the week...
The system is being closely monitored and this bulletin will be updated tomorrow, Tuesday 08 December 2020 at around 10.00 hours.
07 December 2020 Vacoas.}}}
The Joint Typhoon Warning Center (JTWC) released its Advisories on Monday 07 December 2020 as follows:
[[[REMARKS:
070900Z POSITION NEAR 14.8S 81.4E.
07DEC20. TROPICAL CYCLONE (TC) 02S (BONGOYO), LOCATED APPROXIMATELY 713 NM SOUTHEAST OF DIEGO GARCIA, HAS TRACKED WEST-SOUTHWESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS DEEP CONVECTIVE BANDING WRAPPING INTO A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC), WHICH SUPPORTS THE INITIAL POSITION WITH GOOD CONFIDENCE. A 070414Z MHS 89GHZ MICROWAVE IMAGE REVEALS CONVECTIVE BANDING, PRIMARILY, OVER THE SOUTHERN SEMICIRCLE WITH WEAK BANDING WRAPPING INTO THE NORTH QUADRANT AROUND A DEFINED LLCC. CONSEQUENTLY, A 070414Z ASCAT-B IMAGE SHOWS GALE-FORCE WINDS (35-40 KNOTS) OVER THE SOUTHERN SEMICIRCLE WITH 20-25 KNOT WINDS OVER THE NORTHERN SEMICIRCLE. THE INITIAL INTENSITY IS ASSESSED AT 35 KNOTS BASED ON THIS ASCAT DATA AS WELL AS A PGTW DVORAK ESTIMATE OF T2.5 (35 KNOTS). UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH ENHANCED POLEWARD OUTFLOW, LOW VERTICAL WIND SHEAR (VWS) AND WARM SST (28C)...
TC 02S IS FORECAST TO TRACK WEST-SOUTHWESTWARD THROUGH TAU 24 BUT SHOULD TURN SOUTHWESTWARD THROUGH TAU 60 AS A DEEP MIDLATITUDE SHORTWAVE TROUGH APPROACHES AND ERODES THE SUBTROPICAL RIDGE (STR)…
AFTER TAU 60, THE TROUGH WILL PROPAGATE EASTWARD AND A STRONG STR WILL BUILD TO THE SOUTH DRIVING TC 02S WESTWARD THROUGH TAU 120. NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT LENDING MODERATE CONFIDENCE IN THE JTWC FORECAST TRACK. TC 02S WILL INTENSIFY THROUGH TAU 48 TO A PEAK INTENSITY OF 55 KNOTS BUT IS EXPECTED TO WEAKEN STEADILY THROUGH THE REMAINDER OF THE FORECAST PERIOD…
INCREASING VWS, SLIGHTLY COOLER SST (26C) AND WEAK BAROCLINICITY AFTER TAU 72 WILL SUPPORT DISSIPATION BY TAU 120. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070600Z IS 12 FEET. NEXT WARNINGS AT 072100Z AND 080900Z.]]]
Keep Watch for More.
PKANHYE. 15.50 Hours MONDAY 07 DECEMBER 2020.
Update: 12 12 2020