This is a look at the web cam of Las Lenas on June 5th, 2014 after a pretty decent two day storm. The storm was predicted to drop 8-12 inches, it snowed harder then expected and it seems like they received more like 12-18 inches. The storm hit in two parts, the initial jet streak and stream of moisture, and then the low pressure, which stalled and spun off the coast of Termas de Chillan. Termas de Chillan is notorious for experiencing some of the highest snow fall rates in the world, they must have gotten hammered!
As far as actual snow measurements and predictions are concerned. The best way to get an idea of how much snow falls is by concentrating on mid mountain totals. The bottom of Las Lenas sits in a banana belt, and is vertically challenged during warmer storms. While the top of the mountain either gets scoured or ends up with massive amounts of deposition from the insane wind events that occur before,during, and after storms.
Looks like the predicted series of storms is still on track for Las Lenas. The models are showing 3 more storms. The first one is rapidly approaching on Friday afternoon and may be the strongest storm of the entire series. This Friday’s storm according to the models is digging the farthest north and is going to hit the Portillo area pretty hard. Los Penitentes could get 30-45 centimeters.
As far as Las Lenas is concerned the Global Forecasting System (GFS) which typically under estimates snow totals is predicting about 14 inches, while the Canadian Model Center (CMC) is showing as much as 18″-24″. Both models had a lower bias from this last storm, so the possibility of a 2 foot plus storm (60 plus cm) is not out of the question. The storm has plenty of cold air dynamics and a 140 km jet placing Las Lenas in the front right exit region of the jet and associated moisture tap. This should limit the shadowing that normally occurs in Las Lenas due to the multiple higher mountain ranges to their west in Chile.
The second storm in the sequence is right on the heels of Fridays storm which extends into Saturday. It’s due in on Sunday the 8th. This storm is a little warmer and according to the GFS is only expected to drop 2-4 inches, while the CMC is showing 4-6 inches. Leaning with the Canadian and would not be surprised if it turns into more like an 8-10 inch storm from all the antecedent moisture in place from the previous storm.
The third and last storm before the ridge off the Pacific builds back into the coast of Chile, hits Las Lenas on Wednesday the 11th and extends into the morning of the 12th. Best guess on snow accumulations is 8-12 inches for Las Lenas, with 12-16 inches as the high end prediction. This storm looks like it digs farther north hitting Portillo and Los Penitentes with similar to lesser snow totals.
Long Range Forecast
Unfortunately, it appears as though the excitement ends for a while. After the storm exits on the 12th the Pacific ridge progresses back to the west and builds into the coast of Chile redirecting the jet stream to the south. There is a ridge building off the southern coast of Brazil in the Atlantic which is going to constrict the long wave pattern until around the 21st. Looks like the pattern stays progressive so I would expect a pattern shift to occur sooner then later. The jet stays for the most part just to the south of Las Lenas with a continuation of storms pounding Termas de Chillan and most of Patagonia. Winter appears to have arrived in the southern hemisphere. There definitely is some spread in the ensembles and the GFS is flickering like a candle so the possibility of some thing sneaking in during this next 9 day time frame of the extended forecast is not out of the question.
There are signs in the tail end of the ensembles and the GFS model that retrogression of the ridge in the Pacific is going to reoccur beginning on the 21st. The Climate Forecast System (CFS) is showing a return of storms the beginning of the last week of June and the first week of July. This is just an outlook obviously considering it extends an entire month out. The CFS has one run every 24 hours and it quite often flip flops dramatically from one run to the next, hence the name fantasy charts. It has been trending from extremely wet solutions, to periodic storm cycles from mid June through mid July for Las Lenas.