Current Synoptics and Conditions
There has been a change to the conditions over the alps over the past week or so, with colder and snowier conditions becoming more prevalent, more especially over higher slopes. There has been further snow this week, at times to lower levels. However as can be seen when looking at the synoptic chart, winds have returned to a South Westerly direction, so some of the snow has thawed at lower levels. There is also an avalanche at some slopes so be careful off piste.
The South Westerly wind continues, with low pressure in charge, so this is likely to give some rain, heavy in places, with the snow restricted to higher slopes.
Monday and Tuesday
The wind direction changes to more of a Westerly then North Westerly flow, bringing in some colder air from the North west, together with Unsettled conditions remaining in charge, there is the risk of further heavy snowfalls, and to lower levels.
End of Week
There remains a lot of uncertainty as the weather at the end of the week, but looking on the cold side, with further snow at times, perhaps with the risk of much colder from the north edging in by Friday, but this i very uncertain.
Alps Temperatures and Rainfall
For Saturday, a fairly mild South Westerly flow across the Alps, mildest in the far SW, colder in the NE.
850Hpa temps generally +3c to +5c, FL 1800m to 2100m generally, however for the far NE closer to 500m with 850hpa values
Moderate precipitation initially for the west of the Alps, but spreading across the east later in the day, Snow levels (always approximate) initially 1800m, dropping to 1600m by evening, and closer to 1100m by midnight .
For Sunday SW winds again, but starting to turn a little colder to the North west of the Alps.
850Hpa temps generally +3c to +5c, FL 1600m to 2000m generally.
Precipitation to start in Austria, but clearing early afternoon, however more precipitation edges in from the west becoming heavy over SW Germany and parts of Switzerland by evening. Snow levels generally 1200-1500m.
Monday - Tuesday
For Monday Low Pressure over the Alps, with conditions set to turning colder for the far NW, but briefly milder for times further South and East, with a mild sector, but much colder here by evening.
850Hpa temps +1c to +3c, FL 1400m to 1600m for parts of France, NW Switzerland, SW Germany, far North of Austria.
850Hpa temps +3c to +6c, FL 1800m to 2200m elsewhere for a time, but much colder by evening with FL similar to NW areas.
Heavy precipitation to start in the west, this becoming more widespread as the day progresses across much of the Alps, drier into the evening further west, but continuing over Austria into the early hours. Snow level 1400m in the NW to start, 2000m ahead of the rain band, however dropping steadily from the NW to reach 1200m by evening and 1000m by midnight. With the chance of 20cm of snow generally, and 50cm in some spots to the west, perhaps more in places.
For Tuesday, cooler generally with West to North West winds
850Hpa temps -2c to 0c, FL 1100m to 1300m for parts of France, Switzerland, SW Germany
850Hpa temps 0c to +2c, FL 1300m to 1600m for SE Germany, Italy and Austria.
Any overnight sleet/snow clearing Austria during the morning, before more precipitation is set to edge in from the west, however this time this is set to be focussed on France, Switzerland and Southern Germany during the day, before extending across into Western Austria by evening. FL lower then Monday, 1000m daytime, dropping back to 400m-600m by evening. Further heavy snow totals are possible with 50cm locally, but less widespread than on Monday.
Wednesday - Friday
There is a large deal of inter run variation at the moment, comparing the charts below with their 00Hz run (GFS) variation) and the picture looks much different.
However my best guesstimate at the moment is for 850Hpa temps to be below zero, and FL in the range 1000m to 1500m across the Alps. perhaps always that little bit colder further north.
For Friday there is the risk of turning much colder with sub -5c 850hpa air edging in from the north, and FL maybe as low as 500m, but a lot can change between now and then.
In terms of precipitation for these days, the current theme is for precipitation for the north of the Alps Wednesday, to about 1000m, more general precipitation Thursday spreading again from the west, but with potentially high freezing level, but turning much colder Friday, with widespread light to moderate snow.
A lot of precipitation is possible across the Alps, the big question this week is the Freezing Level. With over 1m of snow possible if this came off.
A cool week to come for the Alps, very unsettled with the potential for some large snowfalls, there is the chance of over 1m falling in some higher resorts, say above 1800-2000m. The further sown the mountain, the higher the risk that there will be rain instead of snow, at 1500m, it should be mostly snow after this weekend, so possibly 50cm at 1500m. Below 1000m there are risk that there may be more rain than snow, so conditions very uncertain.