WeatherExtreme Forecast Discussion 8/14/2017 0435Z

Some short wave energy propagating across Argentina Monday and Tuesday with rain or snow showers, shifting upper level winds from westerly to southwesterly with the passage. Winds shift back to westerly late Tuesday night and early Wednesday as the most intense short wave exits to the Atlantic and a warm front comes in from the Pacific. Late Thursday a positive tilt trough with a weak trailing cold front comes onshore bringing light rain or snow flurries. The storm occludes and passes slowly north of El Calafate over the weekend. Another storm may bring heavier rain early next week.

WeatherExtreme Forecast Discussion 8/13/2017 0700Z

Cold front comes ashore north of El Calafate this weekend, bringing a few light rain or snow showers Sunday night. Monday west-southwesterly flow aloft with residual showers in the moist flow west of the ridge line. Some wave flying may be possible Tuesday with strong southwesterly winds aloft. Wednesday brings another weak cold front. More storms may arrive on the weekend.

WeatherExtreme Forecast Discussion 8/10/2017 0745Z

A low pressure area with associated upper level trough currently off the west coast of South America will decouple into a closed low that moves poleward south of Tierra del Fuego and a trough that will dig all the way into the subtropics and come ashore during the day Friday. The upper low will get absorbed into the westerlies but the trough will hang around the entire weekend, before more short wave energy comes ashore on the west coast Sunday night and forces the longer wave off the east coast. The short wave passes north of El Calafate while a large oblate low pressure area passes by to the south, leaving the upper flow Southern Argentina mostly zonal and difluent with some possibility for wave on Monday.

WeatherExtreme Forecast Discussion 8/3/2017 1440Z

Once again there are problems with the local WRF model, so this morning’s forecast is based on ECMWF, GFS, SkySight, RAOB and satellite. Thursday should be much improved for flying with a few scattered low clouds in the morning in El Calafate, becoming mostly clear by afternoon. Surface winds out of the west 10-15 kts gusting to 30. Winds aloft west-southwesterly 50-80 kts above FL100. Moderate wave will be present with vertical velocities 1000-1500 fpm, diminishing above FL200. Orographic precipitation and low clouds will be present west of the ridge line.