SKY CONDITION : overcast in the morning – becoming mostly cloudy – afternoon fleeting sunny spells likely. Period of sunshine close to 15%.
PRECIPITATION : continuous in the morning, changing for showers, gradually scattered – fairly heavy showers resuming from the south towards the evening – rain-snow limit towards 1500 m, rising up towards 1800 m – expected snowfall towards 2500 m : 20-50 cm.
WIND - ground level : variable light – possible f?hn wind puffs in the afternoon.
WIND - mid mountain : SE light.
WIND - high mountain : SSE moderate to strong -> S light to moderate.
TEMPERATURE : low +5°C - high +12°C.
ISOTHERM 0°C : 1800 -> 2100 m.
ISOTHERM -10°C : 3600 -> 3800 m.
Locally heavy showers at first
SKY CONDITION : mostly cloudy – locally cloudy with clear spell towards the end of the night.
PRECIPITATION : frequent and locally heavy showers running over from the south in the first part of the night – rain-snow limit towards 2000 m – probably dry towards the latter part of the night.
WIND - aloft : S light to moderate -> SSW moderate to strong.
TEMPERATURE : low +3°C.
SATURDAY MAY 18
Sunny spell early in the morning, then thick high cloud – strong f?hn wind likely
SKY CONDITION : sunny spells likely early in the morning, then thick high cloud running over from the south. Period of sunshine close to 20%.
PRECIPITATION : probably none.
WIND - aloft : SSW moderate to strong -> S fort – f?hn wind gale likely in the valley.
TEMPERATURE : low +3 °C - high +17°C.
Complex low 995-998 hpa, Spain to Germany, fed by polar air over Western France high up. The whole system is expected to filling while isolating as a low with altitude cold drop over France by Saturday. Linked disturbance still waving over the Alps in the morning in a southerly stream, then moving away eastward, while instability is expected to resuming from the south towards the evening. F?hn wind gale likely on Saturday. Further outlook, very uncertain, doesn’t show any noticeable improvement.