January 22, 2022 6:30 pm

Climatology of linear convective winds in the Balearic Islands 2011-2021. II

RAM Collaborations 12 min
Radar image of the studied area and for illustration only. Meteored

You can check Part I, here.

Results

Of all the years analyzed, 18 events were obtained that have been ordered down from highest to lowest wind intensity. Although the current climate goes from 2011 to 2021, the event of October 4, 2007 has been added for being unique and well documented, although it has not been included in the statistics.

It has been called event to a situation of severe linear convective winds that occurs on the same day (between 00 and 00). In the same event, multiple registrations can occur above the threshold. For example, in event number 1, on January 22, 2021, 90 km / h were exceeded in more than 26 weather stations.
The events have been numbered, indicating the date, time of occurrence and location. In the event that more than one station registered winds> 90 km / h in the same episode, it is indicated below. If in the same event there are several stations that exceed the threshold, the time interval is indicated from when 90 km / h were exceeded for the first time until it was beaten for the last time. Of the events> 120 km / h, radar images from AEMET have been included.

Those wind values ​​accompanied by an asterisk

they refer to intensities not measured by meteorological instruments, but have been estimated from a field work carried out by the AEMET.

Event SummaryEvent 1
: 22-01-2021 (11: 10-12: 20). AEMET and Balears Méteo 197.7 Sa Tudossa,

177 Serra d’Alfàbia, 153 Cap de Formentor, 145 Sant Salvador (Felanitx), 135 Montuïri, 130 Palma aeropuerto, 128 La Bonanova (Palma), 122 Sa Ràpita y Es Mercadal, 116 Campos, 114 Vilafranca de Bonany, 111 Dic de l’Oest and Menorca airport, 109 Santa Maria, 106 Selva, 105 Ciutadella and Cala Galdana (Menorca), 103 Binissalem, 102 Portocolom, 101 Cala Figuera (Santanyí), 100 Ibiza airport, 99.8 Inca, 98 Cap Blanc (Llucmajor), 94 Banyalbufar, 94 Calvià, 96.6 Badia Bay (Llucmajor) and 90 Llubí.

Radar at 11:10 (La Bonanova registers 127.8 km / h at 11.12 and Ciudad Jardín (Palma) 98.1 km / h at 11:19. Squall line with an arc shape, moving from NW to SE. The synoptic wind is intense and it blows in the WSW direction at about 50-60 km / h so that the convective linear winds add to the synoptic wind (both come from similar components) giving rise to hurricane gusts. The squall line appears mixed in stratiform precipitation and tends to lose its linear structure as it crosses Mallorca although the gusts are equally intense.

There is a maximum gust of 130 km / h at the Palma airport at 11:20 while at the Mahón airport they measure 111 just one hour later at 12.20. Assuming a distance of 137 km separating both airports, we can deduce a very fast displacement speed of the squall line, greater than 100 km / h.Event 2
: 29-08-2020 (10: 40-11: 00). AEMET and Balears Méteo171 Banyalbufar

, 135 Campanet, 107.8 Serra d’Alfàbia Balears Méteo, 96.5 Inca and 91 Serra d’Alfàbia AEMET.

Radar images at 8:40 and 8:50 UTC show the presence of a hook-shaped echo in front of the Sierra de Tramontana with a Weak Echo Region on the inside and a V-Notch on the back, denoting strong divergence around the updraft. These are classic patterns in supercells, this one in question having been confirmed as a cyclonic supercell. The inner area of ​​the hook is where the mesocyclone is usually located and coincides with the area where more wind damage was reported.Event 3
: 27-08-2019 (12: 40-13: 20). AEMET and Balears Méteo149.6 Cala Figuera (S

antanyí), 120.7 Cala Santanyí, 106 Far de la Mola (Formentera), 104.6 Sa Ràpita nautical club and 96.5 Campos.

Radar image at the time of measuring 106 km / h at the La Mola lighthouse (Formentera). At 8:10 UTC you can see a discontinuous squall line with considerable thickness. Reflectivities greater than 50 dBz are measured in various segments of the line. The squall line gained organization by going out to sea with various arched segments forming a LEWP (Line Echo Wave Pattern) and presenting notches at the rear.

A few hours later, the squall line reaches Mallorca at around 10:40 UTC showing a concave arc shape when it is about to affect the southwest of the island. The second image, at the time of measuring 149.6 km / h in Cala Figuera (Santanyí), the squall line has lost organization and has thickened, although it still retains its linear shape and shows moderate to strong reflectivities.Event 4
: 22-10-2019 (9: 30-10: 00 and 22: 00-23: 00). AEMET field work 120-140 * Sant Antoni de Portmany

(Ibiza) and 93.2 Serra d’Alfàbia

Radar at 09:50 UTC. Discontinuous squall line, well organized and associated with a mature MCS over Pitiusas, with a wide zone of stratiform precipitation parallel to the convective zone. A particularly intense segment crosses the west of Ibiza (Sant Antoni de Portmany) the LT takes the form of an arc echo shortly after, around 10:00 UTC. The reflectivities on the line range between 48 and 54 dBz. The LT moves from SW to NW.Event 5
: 10-28-2018 (10: 40-11: 00). AEMET field work

140 * Alaior (Menorca)

Multicellular system without a defined shape exits the Menorca channel after affecting Mallorca with a SW-NE displacement. One of the cells intensifies south of Menorca (radar capture 1 at 08:40 UTC) with reflectivities above 50 dBz and crosses the island in just 20 minutes. No squall line or hook is observed and there is no radar image in Doppler mode, so the supercell category is in doubt.Event 6
: 30-08-2012 (17: 50-18: 00). Private station: Àlex Ensenyat.

134 in Andratx

Radar at 16:00 UTC. Small squall line with NW-SE displacement. The reflectivities are very strong between 60 and 66 dBz. Upon reaching the west of Mallorca, the line undulates in at least two arc echoes, one prior to the entry of the storm from the west and another shortly after the arrival of the storm in Palma and its surroundings. A tornado is reported in Andratx, hail of several centimeters and torrential rains. In Santa Ponsa a private station registers a rain rate of more than 600mm / hour.Event 7
: 29-10-2013 (16: 00-18: 00). AEMET and Balears Méteo.116 Ses Salines
, 111.6 Sant Salvador (Felanitx), 107 Campos (Can Sion), 103 Castell d’Alaró (SOMIB), 96 Llucmajor, 93 Es Tren (Santanyí) and Puig de Consolació, 91 Dic de l’Oest and 90 in Porto Petro.Event 8
: 31-07-2021 (23:30). Balears Méteo.
114.3 Chief of FormentorEvent 9
: 04-11-2011 (9: 40-9: 50) Private station: Luís de Vázquez.109 Playa de Palma (Palma)
. Event 10:
12-10-2012 (12.20). Balears Méteo and AEMET. 109 Marratxí
(Es Pont d’Inca) and 107 in SineuEvent 11
: 01-08-2021 (1:00). AEMET.
108 in Es Mercadal (Menorca)Event 12
: 01-24-2013 (9: 40-9: 50). AEMET.
105-137 * in LlucmajorEvent 13
: 10-09-2019 (18: 10-18: 30). Balears Méteo.
104.6 in CamposEvent 14
: 05-10-2014 (12: 20-12: 30). AEMET.
103 at the Capdepera lighthouseEvent 15
: 10-27-2018 (00: 10-00: 30). AEMET.
94 in BanyalbufarEvent 16
: 23-06-2021 (11:52). Balears Méteo.
91.9 in Cap de FormentorEvent 17
: 04-09-2015 (10: 30-10: 40). AEMET.
90 in West DeckEvent 18
: 01-07-2012 (17: 20-17: 30). AEMET.
90 in the Sierra de AlfabiaSpecial event
: 04-10-2007 (17: 20-18: 20). AEMET and private station: Biel Perelló.

110.8 Palma airport, 109 Palma port, 107 Pollença and 95 in Alfàbia

Distribution by intensity

Of the 19 events, 15 of them have exceeded 100 km / h and in 6 the 120 km / h. It is worth emphasizing that of the 6 events> 120 km / h, five of them have taken place in the last 4 years.

The most intense event took place on January 22, 2021 when the Sa Tudossa station (Artà) registered a maximum gust of 197.7 km / h (Balears Méteo). That day, a squall line swept Mallorca associated with a cold front from the Hortense storm. Although the synoptic wind was significant, the report was included since the intensity of the gusts in some cases was five times higher than those measured before the arrival of the squall line.

The second most intense event of the series occurred on August 29, 2020 when the EMA of the AEMET in Banyalbufar registered 171 km / h. A cyclonic supercell affected the area accompanied by 6 cm hail and an EF2 tornado with estimated winds of 171 to 190 km / h.

The event with the most registrations above the threshold was on January 22, 2021 with 27 registrations of more than 90 km / h. The second event with the most registrations occurred on October 29, 2013 with a total of 8.

The following graph shows the distribution of records by intensity. The vertical axis indicates the speed in kilometers per hour in intervals of ten by ten.

Most blowouts in the Balearic Islands belong to the lower category, with maximum winds between 90 and 100 km / h which represents a total of 39 registered cases (73%). The number of registrations drops to 8 if we raise the threshold by only 10 km / h (up to 110 km / h) and remains stable between 120 to 150.

It is still striking that in such a short reference period, we have 15 records of hurricane-force winds or more, representing 28% of the total sample.

Next, a summarized table with the events is presented, indicating only the maximum streak of the day in case there was more than one record equal to or greater than 90Km / h and information on the island where it was recorded, the radar archetype. dominant, time and season of the year. Below the table is the legend with the meaning of each abbreviation.

In the first place, it should be noted that 100% of the events in the present climate occurred in maritime multicellular storms. From this study it is therefore extracted that severe linear winds between 2011 and 2021 are non-existent in unicellular storms and in terrestrial multi-cells generated by diurnal convection and / or convergence of breezes.

30-11-2021

Duncan Wingen Sanchez

To be continue

This entry was published in News on Dec 04, 2021 by Francisco Martín León

Reference-www.tiempo.com

Comments (0)

Leave a Reply

Your email address will not be published. Required fields are marked *