CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST

From http://chamonix-meteo.com

ISSUED AT 21:35 ON SUNDAY OCTOBER 20, 2019

GENERAL SYNOPSIS

High pressure, Tyrrhenian Sea to Black Sea, reinforced by African component high up, Tunisia to Austrian Alps. • Frontal through, Baltic Sea to Southern Portugal, getting cut-off as an altitude cold drop over Bay of Biscaye by Monday morning, and minimum 1004 hpa over Central France, drifting west while filling. • Resulting south gale will therefore decrease slightly high up, while fœhn gradient between Savoie and Italian Piedmont will be loosening almost completely by the middle of the night. • Bay of Biscaye altitude cold drop will keep southerlies streaming all day long on Monday, thus driving light rain at first, then moderate over our Region between mid-morning and late afternoon.

SUNDAY EVENING OCTOBER 20 - AND OVERNIGHT

Becoming mostly cloudy from south - gale high up - shower risk

SKY CONDITION : mostly cloudy with cloud running over from south - fleeting clear spells.
PRECIPITATION : risk of shower running over from south - rain-snow limit dropping towards 2900 m by dawn.
WIND - ground level : foehn puffs until the middle of the night - maybe somewhat later in the upper valley - else variable light.
TEMPERATURE : low +8°C.
ISOTHERM 0°C : 3400 -> 3200 m.
ROAD CONDITION  : recent snow shower. Locally whitened roadways. (Sun. 06:15).

TOMORROW - MONDAY OCTOBER 21

Gloomy, yet fairly mild - south near gale high up - rainy

SKY CONDITION : mostly cloudy to overcast - fleeting clear spells likely later in the afternoon. Period of sunshine close to 5%.
PRECIPITATION : isolated shower early in the morning, turning into continuous rain - temporary lull towards the end of the afternoon - rain-snow limit towards 2900 m, rising - expected amount of water in the valley : 8-12 mm.
WIND - ground level : variable light.
TEMPERATURE : low +8°C - high +12°C.

MONDAY TO TUESDAY NIGHT - OCTOBER 21 TO 22

Another rainy spell, then improving - decreasing wind high up

SKY CONDITION  : overcast, then mostly cloudy in the first part of the night - fair sunny spells spreading high up there after - stratus cloud probably condensing in the valley.
PRECIPITATION : moderate rain resuming in the first part of the night - ending soon after midnight - rain-snow limit towards 3200 m, rising - expected amount of water in the valley : 8-12 mm.
WIND - aloft : SSW fort -> S modéré.
TEMPERATURE : low +7°C.

TUESDAY OCTOBER 22

Fairly sunny after low cloud dispelling - very mild in the afternoon

SKY CONDITION : broken stratus cloud toping towards 1200-1300 m by dawn, dispelling under direct sunshine - else, partly cloudy - high cloud crossing from south. Period of sunshine close to 60%.
PRECIPITATION : none.
WIND - aloft : S moderate.
TEMPERATURE : low +6 °C - high +19°C.

WEDNESDAY OCTOBER 23

 : clear or partly cloudy - becoming cloudy from south towards the end of the afternoon. Period of sunshine close to 75%.