Very severe storms are forecast by MetSul Meteorologia for the provinces of central Argentina on Tuesday afternoon and evening and between sunrise and Wednesday morning. The meteorological scenario is consistent with the formation of storm supercells, which have the potential to spawn very intense and destructive storms in some locations.
Provinces such as La Pampa, Córdoba, Buenos Aires, Santa Fe and Entre Ríos are in the severe weather risk zone. Atmospheric conditions will deteriorate very rapidly as the hours tick by in the second half of Tuesday and early Wednesday in that region, with the formation of multiple storm surge areas and extremely heavy clouds, peak temperatures of which may have temperatures of 80C or less.
This is a particularly dangerous severe weather condition due to the high risk of locally very intense to violent storms with destructive wind and hail potential. The city of Buenos Aires and its conurbation, the socalled conurbano, are among the places with a high risk of severe weather.
Analysis of the atmospheric dataset projected by the numerical model package suggests storms with locally torrential rain, but the biggest concern is the prospect of occasional severe to violent hailstorms which can be large in some locations and windstorms with the risk of dowbursts and even the occasional formation of tornadoes.
The maps below show hail forecasts for Tuesday afternoon and evening based on the North American GFS model. It is observed that the probability of hail is very high in central Argentina, especially in the provinces of La Pampa, Cordoba, Santa Fe and Buenos Aires.
The scenario is critical for severe weather in central Argentina in one of the most dangerous situations for recent severe thunderstorms in the neighboring country. All the ingredients that increase the potential for storms will be in place between this Tuesday and Wednesday.
Firstly, a low pressure center will act in the region with very low surface pressure values. Models indicate the possibility of 995 hPa to 998 hPa in Buenos Aires province, with values below 1,000 hPa being particularly critical for severe weather.
Second, a low jet stream (JBN or LLJ) will carry very hot air into the region where the storms will form. The jet will be very intense, with winds between 1000 and 2000 meters in altitude, from 100 km/h to 150 km/h. As a cold front advances, the divergent wind pattern (shear) will be tremendous, creating favorable conditions for tornadoes.
Third, a cold front will advance over an air mass that is too hot for this time of year in an environment of extreme instability with low atmospheric pressure and a very intense lowlevel jet stream.
Therefore, numerical models project extremely high instability indices for central Argentina. Indices such as CAPE, Lifted, SWEAT and Showalter have values projected by numerical models between the afternoon and evening of Tuesday and the beginning of Wednesday in very bad weather.
It’s important to emphasize that This critical severe to violent storm scenario applies to central Argentina and not Rio Grande do Sul. Uruguay will also experience severe instability during the alert period, moving into gaucho territory, but although there is a risk of storms in Rio Grande do Sul, the scenario in Argentina is not as serious as expected..
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