Fig. 1
Geography of the region under study. (a) Political map and approximate locations of the moisture sources discussed in the text. (b) Outer domain of integration of WRF, with orography. The white stars indicate the positions of the four storms studied in the text. The WRF domain position is also reported in panel a in grey.
Fig. 2
Storm of 2 February 2010: (a) radar reflectivity (dBZ). At 22:40 UTC, the maximum reflectivity is found over La Central (68°W, 33.3°S). (b) Longitude/altitude cross-section (33°S) of relative humidity (colours) and temperature (°C, black lines). (c) Cloud top temperature (K). (d) Longitude/altitude cross-section (33°S) of vertical air velocity (m s−1, colours) and temperature (°C, black line). Panel a is provided from the Argentinian Meteorological service, panels b and d are issued from the inner domain of the WRF integration and panel c is issued by Service d'Archivage et de Traitement Météorologique des Observations Satellitaires. See text for details. All figures are at 23 UTC. These and all following figures, unless specified differently, are obtained from the highest resolution WRF integration and show the whole inner domain. (e) Longitude/latitude cross-section of vertical air velocity (m s−1) at 10 km altitude. (f) Vertical profiles of vertical velocity (m s−1) at the locations of the maximum updraft and downdraft. (g) Longitude/latitude cross-section of MEC (W kg−1, colours) at 2.5 km altitude and horizontal wind vectors (m s−1) at the same altitude.
Fig. 3
Storm of 2 February 2010: (a) ground pressure (hPa, colours) and horizontal wind vectors (m s−1) at 850 hPa obtained from ECMWF forecast at 21 UTC. (b) 3-D 6-d back-trajectories starting from the convective area at 3 km altitude, and specific humidity (g kg−1, colours) near the ground on 28 January at 00 UTC. (c) Longitude/altitude cross-section (33°S) of SCLW (g m−3, colours) and temperature (°C, black lines).
Fig. 4
Displacement of the storm of 2 February 2010. MEC (W kg−1, colours) and wind vectors (m s−1) at 2300 m on (a) day 2 at 22 UTC, (b) day 2 at 23 UTC, (c) day 3 at 00 UTC and (d) forward trajectories starting from the place of the storm at five different altitudes on day 2 at 22 UTC. Storm of 2 February 2010: passage of a cold front. Magnitude of the temperature gradient (K km−1, colours) at 3 km height on day 2 at 22 UTC (e); on day 2 at 23 UTC (f) and on day 3 at 00 UTC (g). (h) CAPE (j kg−1) obtained from WRF model and the diagram.
Fig. 5
Storm of 2 February 2010, mountain waves near the place and time of the storm. (a) Longitude/altitude cross-section of vertical air velocity (m s−1, colours) and temperature (°C, black lines); (b) longitude/altitude cross-section of relative humidity (colours) and temperature (°C, black lines) and (c) a zoom around 8 km height of a longitude/altitude cross-section of water vapour (g kg−1, colours) and temperature (°C, black lines). All figures are at 23 UTC and at latitude 34.5°S.
Fig. 6
Storm of 2 February 2010, more about mountain waves. Longitude/height cross-section at 34.5°S of (a) wind vector (zonal-vertical); (b) temperature (°C); (c) relative humidity (colours) and temperature (°C, black lines); (d) water vapour (g kg−1, colours and temperature in °C, black lines) and (e) rain (mm h−1) as a function of longitude.
Fig. 7
Storm of 2 February 2010, another mountain wave at 22 UTC. (a) Longitude/altitude cross-section of the vertical wind (m s−1, colours) and temperature (°C, black lines); (b) longitude/altitude cross-section of the relative humidity (colours) and °C (black lines). Both cross-sections are at latitude 34.5°S. (c) 3-D 2 d forward trajectories starting from the place and time of the mountain wave and the place of the convection (the circles) at 22 and 23 UTC.
Fig. 8
Storm of 12 February 2010. (a) Radar reflectivity (dBZ). At 23 UTC, the maximum reflectivity is found over Gral Alvear (67.7°W 35°S); (b) longitude/altitude cross-section of relative humidity [colours) and temperature (°C, black lines)]; (c) cloud top temperature (K); (d) longitude/altitude cross-section of vertical wind (m s−1, colours) and temperature (°C, black lines); (e) ground pressure (hPa, colours) and horizontal wind vector (m s−1) at 850 hPa obtained from ECMWF analysis on day 13 at 00 UTC. Panels b and c are taken at latitude 35°S and at 23 UTC.
Fig. 9
Storm of 12 February 2010: (a) orography (m, colours) and wind vector (m s−1) at 3 km altitude using the WRF first inner domain; (b) MEC (W kg−1, colours) and wind vector (m s−1) at 2300 m; (c) cold front identified by the magnitude of temperature gradient (K km−1) at 2500 m; (d) longitude/latitude cross-section of water vapour concentration (g m−3); (e) longitude/altitude cross-section of SCLW (g m−3, colours) and temperature (°C, black lines) at latitude 35°S and (f) the CAPE (J kg−1) obtained from WRF model and the diagram. All figures are for 23 UTC.
Fig. 10
Storm of 12 February 2010; mountain wave. Longitude/altitude cross-section at latitude 34.5°S and at 23 UTC of (a) vertical wind (m, colours) and temperature (°C, black lines) and (b) relative humidity (colours) and temperature (°C, black lines).
Fig. 11
Storm of 17 December 2009. (a) Radar reflectivity (dBZ). At 20.20 UTC, the maximum reflectivity is found over Rama Caida (68.4°W, 34.7°S). Longitude/altitude cross-section at latitude 34.5°S and at 20:30 UTC of (b) relative humidity (colours) and temperature (°C, black lines); (c) vertical air velocity (m s−1, colours) and temperature (°C, black lines); (d) ground pressure (hPa, colours) and horizontal wind vector (m s−1) at 850 hPa obtained from ECMWF forecast on day 17 at 21 UTC; (e) 3-D 6-d back-trajectories starting from the convective area at 3 km altitude, and specific humidity (g kg−1, colour) near the ground on 11 December at 21 UTC.
Fig. 12
Storm of 17 December 2009. (a) Longitude/latitude cross-section at 3 km height and at 20:30 UTC of (a) MEC (W kg−1, colours) and horizontal wind vector (m s−1) and (b) cold magnitude of temperature gradient (K km−1, colours) and (c) longitude/altitude cross-section at latitude 34.5°S and at 20:30 UTC of SCLW (g m−3, colours) and temperature (°C, black lines).
Fig. 13
Storm of 22 February 2011: (a) radar reflectivity (dBZ). At 20.30 UTC, the maximum reflectivity is found over San Rafael (68.3°W, 34.5°S); (b) ground pressure (hPa, colours) and horizontal wind vector (m s−1) at 850 hPa obtained from ECMWF forecast on day 22 at 21 UTC; (c) 3-D 6-d back-trajectories starting from the convective area at 3 km altitude, and specific humidity (g kg−1, colours) near the ground on 16 February at 21 UTC; (d) orography (m, colours) and wind vector (m s−1) at 3 km altitude using the WRF first inner domain.
Fig. 14
Storm of 22 February 2011. (a) MEC (W kg−1, colours) and horizontal wind vector (m s−1) at 2300 m; longitude/altitude cross-section at latitude 34.5°S and at 20:30 UTC of (b) vertical wind (m s−1, colours) and temperature (°C, black lines) and (c) relative humidity (colours) and temperature (°C, black lines); (d) longitude/altitude cross-section of SCLW (g m−3, colours) and temperature (°C, black lines).