FRANCISCO Moderate Tropical Storm Rapid Formation
6th for South Indian Ocean Season 2019-2020
(EDDIES and VORTICES explained below)
Several times mentions have been made in various articles that the Weather Pattern in the South Indian Ocean has changed consistently. Eddies and Vortices have invaded the Troposphere along the Inter-Tropical Convergence Zone (ITCZ) of the Tropic of Capricorn since a few years. These Systems often herald the oncoming Weather, Climate and Hydrology parameters of the particular zone. See pictures above.
After a series of cyclones, namely AMBALI, BELNA, CALVINIA, DIANE and ESAMI, it is now the turn of the 6th one for the Summer Season 2019-2020. The Low Pressure 90S INVEST as per the Joint Typhoon Warning Center (JTWC) which was evolving near Latitude 9.10 South and Longitude 62.60 East approximately 488 Nautical Miles (807 km) South-East of Seychelles Archipelago has undergone a rapid intensification since 01 February 2020. The System has been upgraded to a Tropical Disturbance and to a Tropical Depression in the early hours this morning.
The Mauritius Meteorological Services has this time named it as Moderate Tropical Storm FRANCISCO at 07.00 am Wednesday 05 February 2020, after further intensification. So, it has crossed the threshold of 63 kph of Wind Force at the centre. Refer to the chart of MFR below. It is located 1135 km East North-East of Mauritius and 570 km East North-East of Rodrigues Island. It is moving in a general South-Easterly direction at about 25 kph.
PKANHYE. 10.50 am WEDNESDAY 05 FEBRUARY 2020.
Joint Typhoon Warning Center (JTWC)
The Joint Typhoon Warning Center has been monitoring very closely, since 01 February 2020, the evolution of the Low Pressure and named it 90S INVEST. The system intensified gradually on 03 February and was upgraded to Medium. 90S INVEST underwent further intensification rapidly, reaching the threshold of 65 kph at the circulation center on 04 February.
<<< ABIO10 PGTW 011800
AN AREA OF CONVECTION (INVEST 90S) HAS PERSISTED NEAR 9.1S
62.6E, APPROXIMATELY 488 NM SOUTHEAST OF SEYCHELLES. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY AND A 011254Z SSMIS 91GHZ IMAGE DEPICT BROAD, BUILDING CONVECTION OVER AN ILL-DEFINED LOW LEVEL CIRCULATION…
A 011507 ASCAT-A IMAGE DEPICTS A BROAD WIND FIELD WITH NO DEFINED CIRCULATION. UPPER LEVEL ANALYSIS INDICATES INVEST 90S IS IN A MARGINAL ENVIRONMENT WITH MODERATE DUAL CHANNEL OUTFLOW AMD LIGHT TO MODERATE (10-20KTS) VERTICAL WIND SHEAR. WARM (29-31C) SEA SURFACE TEMPERATURES ARE FAVORABLE FOR DEVELOPMENT…
GLOBAL MODELS ARE IN GOOD AGREEMENT THAT INVEST 90S WILL GRADUALLY INTENSIFY AS IT TRACKS SOUTHEASTWARD. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1010 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW. >>>
Météo-France-Réunion-RSMC
Météo-France-Réunion which is the Regional Specialized Meteorological Centre (RSMC) for South-West Indian Ocean mentioned almost the same parameters. According to its Advisories released on 05 February 2020, the Weather System was Forecast to evolve as Moderate Tropical Storm status and a rapid weakening by 07 February:
[[[WTIO31 FMEE 050607 CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION.
1.B PREVISIONS:
12H: 05/02/2020 18 UTC: 18.7 S / 70.3 E, VENT MAX= 045 KT, TEMPETE TROPICALE MODEREE
24H: 06/02/2020 06 UTC: 19.5 S / 70.0 E, VENT MAX= 045 KT, TEMPETE TROPICALE MODEREE
36H: 06/02/2020 18 UTC: 19.8 S / 69.4 E, VENT MAX= 040 KT, TEMPETE TROPICALE MODEREE
48H: 07/02/2020 06 UTC: 19.9 S / 68.5 E, VENT MAX= 035 KT, DEPRESSION TROPICALE
60H: 07/02/2020 18 UTC: 20.2 S / 67.2 E, VENT MAX= 030 KT, DEPRESSION TROPICALE
72H: 08/02/2020 06 UTC: 20.3 S / 65.9 E, VENT MAX= 025 KT, DEPRESSION SE COMBLANT
2.B TENDANCE ULTERIEURE:
96H: 09/02/2020 06 UTC: 20.6 S / 64.4 E, VENT MAX= 020 KT, DEPRESSION SE COMBLANT
120H: 10/02/2020 06 UTC: 20.8 S / 62.9 E, VENT MAX= 020 KT, DEPRESSION RESIDUELLE.]]]
Mauritius Meteorological Services (MMS)
The MMS has been mentioning the formation of the Low Pressure since 04 February 2020. Thereafter, reference has been made as Tropical Disturbance and Tropical Depression, in the paragraph under Supplementary Information. The Weather System was named on Wednesday 05 February as Moderate Tropical Storm FRANCISCO.
{{{Forecast Bulletin - Mauritius
WEATHER NEWS FOR MAURITIUS ISSUED AT 16H30 ON TUESDAY 04 FEBRUARY 2020.
GENERAL SITUATION:
The combined effect of an anticyclone to the South of the Mascarenes and a tropical disturbance evolving to the North-East is causing a rather windy weather over our region.
On the other hand, an instability line is influencing the local weather while gradually moving towards the West…
Wind will blow from the East-South-East at 30 km/h in mean with gusts that could reach 70 km/h in exposed areas.
Sea rough beyond the reefs.
Ventures in the open sea are not advised.
Supplementary Information:-
The tropical disturbance evolving to the North-East of the Mascarene Islands may intensify further in the coming days.}}}
{{{WEATHER NEWS FOR MAURITIUS ISSUED AT 04H30 ON WEDNESDAY 05 FEBRUARY 2020.
Supplementary Information:
During the night, the tropical disturbance has intensified into a tropical depression. It may intensify further during the day while moving towards the South-East.}}}
At 07.00 am on 05 February 2020 the MMS named the Tropical Depression while it was located 1135 km East North-East of Mauritius and 570 km East North-East of Rodrigues:
{{{The tropical depression evolving to the East-North-East of Rodrigues has intensified into a Moderate tropical storm and was named as FRANCISCO. It is moving in a general South-Easterly direction at about 25km/h.}}}
{{{WEATHER NEWS FOR MAURITIUS ISSUED AT 05H00 ON THURSDAY 06 FEBRUARY 2020.
Supplementary Information:
At 0400 hours, the moderate tropical storm FRANCISCO was centred in latitude 18.0 degrees South and 71.4 longitude degrees East, that is at about 1445 km to the East-North-East of Mauritius. It is moving in a general South-Easterly direction at about 20 km/h.
Moderate Tropical Storm FRANCISCO is moving in a general South-Easterly direction at about 20km/h. FRANCISCO is expected to weaken during the day…
Distance from Rodrigues 855km ENE. }}}
Update: 23.01 hrs WEDNESDAY 05 FEBRUARY 2020
Keep watch for more soon.
PKANHYE. Re-Uploaded: 10.50 am THURSDAY 06 FEBRUARY 2020.
By 16.00 hours on Thursday 06 February 2020, Moderate Tropical Storm FRANCISCO weakened into a Tropical Depression. Located at1450 km almost to the East North-East of Mauritius, it has been moving in a general south-easterly direction at reduced speed of about 10 kph. Thereafter it started moving South-Westerly at the same speed and continues up to Saturday 08 February.
Although, it is nearing the Southern zone of Rodrigues, FRANCISCO is forecast to remain as a Tropical Depression until Sunday 09 February 10. It is further forecast to spend its last phase as Remnants. However, it may change direction from South of Rodrigues to move up Northwards of Mauritius. All these are subject to the impacts of the Vortices and of dry air, according to the last Advisories of Météo-France-Réunion (MFR- RSMC).
Furthermore, the MMS released is latest Special Weather Bulletin at 10.45 am Saturday 08 February mentioning that FRANCISCO has been downgraded into a Tropical Disturbance. See below.
{{{Special Weather Bulletin
Sat, Feb 8, 2020
INFORMATION ON TROPICAL DISTURBANCE FRANCISCO ISSUED AT 10H45 THIS SATURDAY 08 FEBRUARY 2020.
The tropical depression FRANCISCO has weakened into a tropical disturbance. At 1000 hours, it was located near latitude 20.1 degrees South and longitude 67.5 degrees East.
Distance from Rodrigues : 425 km to the east
Distance from Mauritius : 1010 km to the east.
It is now moving towards the west at about 10 km/h.
On this trajectory, it is approaching Rodrigues. It is expected that the center of the system will pass very close to Rodrigues in the night of Sunday 09 and early morning of Monday 10 February.
The combined effect of the anticyclone to the south and the tropical disturbance FRANCISCO is causing a windy weather and rough seas in the region of Rodrigues. Wind will blow from the south east at a mean speed of 35 km/h and gusts may reach 75 km/h in well exposed areas. Ventures at sea are not advised.
As at now Cyclone Warning is not envisaged for Rodrigues.
The situation is being closely monitored.}}}
PKANHYE. 11.23 am SATURDAY 08 FEBRUARY 2020.
Phenomenal Tropical Disturbance
It is worthwhile mentioning that FRANCISCO has been downgraded into a Tropical Disturbance. However, it continues to influence Weather considerably in the zone of the Mascarene Islands: Reunion, Mauritius and Rodrigues. Previously, it has been stated that the Weather System in the South Indian Ocean has much changed, in which a Phenomenon of FLOOD STORM System is prevailing since a few years. This is also much influenced by the Eddies and Vortices which have also developed in the Troposphere along the ITCZ. DIANE and FRANCISCO stand as particular examples as far as Climate, Weather and Hydrology are concerned. It means that the Protocols regarding classifications of Cyclone Intensity demands review.
The Mauritius Meteorological Services (MMS) released at 16.00 hrs Monday 10 February 2020 a STRONG WIND WARNING for Mauritius valid until 16.00hrs on Tuesday 11 February. The same Warning was maintained as at 4.30 am Tuesday 11 February:
{{{WEATHER NEWS FOR MAURITIUS ISSUED AT 04H30 LT ON TUESDAY 11 FEBRUARY 2020.
GENERAL SITUATION:
(1) A strong wind warning is in force in Mauritius valid till 16h00 today Tuesday 11 February.
The combined effect of the anticyclone to the south and the tropical disturbance FRANCISCO is causing a windy weather and rough to locally very rough seas in the region of Mauritius.
At 0400 hours, it was centered around the points 20.1 degrees South in latitude and 59.9 degrees East in longitude, that is about 230 km to the East of Mauritius. It is moving towards the West-North-West at about 25 km/h and is approaching Mauritius.
(2) On the other hand, clouds associated with the tropical disturbance are influencing the local weather. }}}
The MMS has recorded, as at 11.30 am Tuesday 11 February 2020, the following during the last 24 hours:
FRANCISCO was about 140 km to the east-north-east of Mauritius and is moving towards the West North-West at 25 kph.
Wind Speed:
Grand Basin and Le Morne-61 kph and Queen Victoria and Champ de Mars-58 kph, amongst others.
Rainfalls:
Grand Bassin-65 mm; Mon Bois-51.4 mm and Mare Aux Vacoas-48.1 mm.
Temperature is 320 Celsius (max) and
Humidity is on the High Side-66-94%.
PKANHYE. 11.55 am TUESDAY 11 FEBRUARY 2020.
FRANCISCO Disturbance continued to influence and threaten the Mascarene Islands. The Warning of HIGH WAVES was added, by the MMS, to the Bulletins during the day. Refer to the following:
{{{Special Weather Communiqué issued at 10h30 this Tuesday 11 February 2020.
A 'Strong Wind' and 'High Wave' Warning is in force in Mauritius valid till 10h00 tomorrow Wednesday 12 February.
The combined effect of the anticyclone to the South of the Mascarenes and the tropical disturbance FRANCISCO will cause a very windy weather over Mauritius and very rough seas beyond the reefs.
Wind will blow from the South-East at a mean speed of about 45 km/h with gusts which could reach 90 km/h in exposed areas.
The open seas will be very rough with swells of about 4 meters.
Some useful advice:
i) avoid manoeuvres on tall buildings and other high structures.
ii) be very cautious while driving along roads with strong crosswinds.
iii) refrain from venturing in the high seas and the lagoons. }}}
All Strong Wind and High Waves Warnings have been waived by the MMS during the morning of Wednesday 12 February 2020.
MMS Records on 12 February 2020 are as follows:
Rainfalls:
Mon Bois-44 mm; Vacoas- 38.9 mm; Grand Bassin-38.8 mm; Mare Aux Vacoas-37.4 mm; Riche Terre-34.8 mm and Chitrakoot-28.7 mm, mainly.
Wind Speed:
Champs de Mars-90 kph; Signal Mountain-87 kph; Le Morne-72 kph Nouvelle Decouverte-68 kph and SSR Plaisance Airport-63 kph, mainly.
Sea Swells- 4.5 mt; Temperature-320 Celsius and Humidity-66-98%.
The Atmosphere around Mauritius remained unstable throughout the evolution of FRANCISCO, whether it was a Moderate Tropical Storm or A Tropical Depression or a Tropical Disturbance.
As at today 13 February 2020, the Remnants of FRANCISCO are still moving at 20 kph towards the West South-West. It will surely reach the Eastern Coasts of Madagascar within a few days and shower Rains until its Central Mainland. The Atmospheric Pressure at the centre is 1000 hpa. It may also re-intensify further soon.
PKANHYE. Updated: 21.30 hrs THURSDAY 13 FEBRUARY 2020.
Météo Madagascar and FRANCISCO
FRANCISCO has re-intensified from Tropical Disturbance to Tropical Depression on Thursday 13 February 2020. This probability was mentioned earlier above. Météo Madagascar released its Special Weather Bulletin, as it is nearing 100 km of Madagascar Eastern coasts. The Wind Force at the centre is estimated to 55 kph with gusts reaching 75 kph. FRANCISCO is moving Westwards at 12 kph, but is forecast to track towards the South-West and West during the coming two days. A Heavy Rain Warning has also been issued for some regions. Refer to the picture below.
///Bulletin cyclonique special du 13 fevrier 2020 à 19 heures locales et Prévision de trajectoire
par scom | jeu, 02/13/2020 - 20:24.
Le résidu de la tempête FRANSCISCO s’est rapproché de la côte Est du pays depuis les cinq derniers jours. Aujourd'hui 13 février 2020 à 18 heures locales, son centre est positionné à environ 100 Km au Sud-Est de Toamasina. Une légère intensification a été constatée depuis ce midi et a permis de le classer à nouveau comme étant une Dépression Tropicale. Le vent moyen est faible à 55 Km/h avec des rafales de 75 Km/h. Elle se déplace globalement vers l’Ouest à 12 Km/h. D’après la prévision, elle devrait atterrir aux environs de Vatomandry et Mahanoro dans la journée du Samedi au même stade de Dépression Tropicale.
Il n’y a pas d’Alerte Cyclone étant donné que la probabilité d’intensification en Tempête Tropicale Moderée est évaluée à faible.
- Toutefois, les fortes pluies seront au rendez-vous avec une possibilité des rafales de 70 Km/h durant la journée de l’atterrissage. La vigilance est donc de mise.
- La sortie en mer est déconseillée entre Cap Masoala et Manakara jusqu’à écartement de dangers.
- Les populations concernées sont priées de se conformer aux consignes émises par les autorités locales.///
Keep Watch on more information regarding EDDIES and VORTICES soon.
PKANHYE. Updated: 18.08 hrs FRIDAY 14 FEBRUARY 2020.
EDDIES and VORTICES
The Pacific Ocean has, since many decades, been subject to major researches regarding the Atmosphere and Ocean Studies, amongst others. The ENSO (El Nino/La Nina and Southern Ocean) mainly dealt with the Pacific Warm Pool, wherefrom Global Warming: Drought, Heat, Cyclones, Hurricanes, Typhoons, Floods etc. seriously affect the whole world.
It seems that there is a paradigm shift in researches/studies towards the Indian Ocean, where the Indian Ocean Dipole (IOD) System, The Madden Julian Oscillation (MJO), the Inter-Tropical Convergence Zone (ITCZ), the South-East Trade Winds (SETW) and the Antarctic Circumpolar Current (ACC) are in focus.
Mention has been made in previous articles, since long, that the landmasses of Africa, Antarctica and Australia are the real Barometers of the Southern Indian Ocean. In this context, it was also stated that all the Heat, Carbon emissions (carrying salinity) and Pollution originating from the Forest/Bush Fires in Australia converge towards the Indian Ocean and also cause impacts on Global Atmosphere and Oceans. Researchers now mention that these are now being studied and are, therefore, real.
According to NOAA, Eddies are defined as follows:
<<< An eddy is a circular current of water.
The ocean is a huge body of water that is constantly in motion. General patterns of ocean flow are called currents. Sometimes theses currents can pinch off sections and create circular currents of water called an eddy.
You may have seen an eddy if you've ever gone canoeing and you see a small whirlpool of water while you paddle through the water. The swirling motion of eddies in the ocean cause nutrients that are normally found in colder, deeper waters to come to the surface…
transport properties such as heat, salt and carbon around the ocean…In the Southern Ocean, eddies account for the majority of oceanic poleward heat transport across the Antarctic Circumpolar Current.>>>
See South Pole picture on the Right.
https://www.gfdl.noaa.gov/ocean-mesoscale-eddies/
Eddies (circular currents), apart from oceans, can also be seen in rivers, lakes, ponds, and seas. They are also visible in the Atmosphere, particularly in bands of Clouds. Researchers explain that Stratocumulus Clouds exhibit Eddies.
There may be one Eddy moving turbulently. When its movement is obstructed by an object, it flows in a Chain of Eddies. This is more fully explained in Fluid Dynamics NOAA Ocean Mesoscale Eddies:
“Theodore von Kármán, a Hungarian-American physicist, was the first to describe the physical processes that create long chains of spiral eddies like the ones shown above. Known as ''von Kármán vortices", the patterns can form nearly anywhere that fluid flow is disturbed by an object. In this case, the unique flow occurs as winds rush past the tall peaks on the volcanic islands. As winds are diverted around these high areas, the disturbance in the flow propagates downstream in the form of vortices that alternate their direction of rotation.”
A Vortex Street can be seen, not only a series of close Islands, but also across a mountain range in which you can feel a Turbulent Air moving. It can better be felt/seen along a street where there are a series of tall buildings. So, the Air moves speedily along and across the space found around the buildings. In such a circumstance you should have noticed that umbrellas, coats, neckties, dresses of men and women are blown apart by the Flow of the Wind. Such whirlpools may exist for a few minutes or for a month+ and extend up to tens of kilometres.
Refer to the animated picture below to appreciate the Whirlpool behaviour of EDDIES and VORTICES as far as the Storms, Cyclones and Floods which are prevailing these days, are concerned: CALVINIA, DIANE, ESAMI, FRANCISCO, GABEKILE and the current Extra-Tropical Storm DENNIS in Europe eg.
NB: Refer to the NASA picture of the “Marine Stratocumulus Clouds” dated 11 March 2013, which caused the Mega/Deadly Flash Flood of 30 March 2013 in Mauritius. An EDDY is located on the Right hand side.
FRANCISCO, male name, has been provided by Mozambique.
Keep watch for the next ones.