CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Natsume Sôseki
Evening let them glow
Red mountains
In a radiant window
ISSUED AT 19:35 ON THURSDAY AUGUST 25, 2016
VALID FROM : THURSDAY AUGUST 25 -- UNTIL : WEDNESDAY AUGUST 31 2016

GENERAL SYNOPSIS
High 1025-1026 hpa, Eastern Poland and Western Russia, weakening slowly almost stationary. Thermal low over Northern Spain, drifting slowly over Biscaye Bay and finally reaching the British Isles by Sunday; it's unstable influence should not reach the Western Alps until Saturday noon. • Fair and clear night, then sunny on Friday, hot from noon in the valley, with some cumulus cloud over the massifs at last, and considerably warmer than seasonal average in the median altitude range, thanks to the inflow of a sub-tropical component high up which contributes to reinforce the anticyclonic dome effect. • Diurnal evolution favouring late afternoon thundery shower outbreaks should be resuming from Saturday.
THURSDAY EVENING AUGUST 25 - AND OVERNIGHT
Fair summer night - almost warm in the median altitude range
SKY CONDITION : clear.
PRECIPITATION : none.
WIND - ground level : variable -> NE light.
WIND - mid mountain : ESE light -> calme -> NE light.
WIND - high mountain : S -> SSW light.
TEMPERATURE : low +12°C.
ISOTHERM 0°C : 4700 -> 4600 m.
ISOTHERM -10°C : 6200 -> 6100 m.
Very mild in the median altitude range. Snow surface refreezing high up : poor or non-existent.
TOMORROW - FRIDAY AUGUST 26
Fair weather ‑ hot and even sultry in the afternoon
SKY CONDITION : clear or partly cloudy - some cumulus cloud growing over the massifs. Period of sunshine close to 95%.
PRECIPITATION : none.
WIND - ground level : NE light - thermal SW light to moderate at times.
WIND - mid mountain : NE -> variable light.
WIND - high mountain : SSW light.
TEMPERATURE : low +11°C - high +30°C.
ISOTHERM 0°C : 4600 m.
ISOTHERM -10°C : 6100 m.
Same weather all over the neighbouring massifs.
FRIDAY TO SATURDAY NIGHT - AUGUST 26 TO 27
Clear and very mild, especially in the median altitude range
SKY CONDITION  : clear after possible evening cumulus cloud dispelling.
PRECIPITATION : none.
WIND - aloft : SSW light.
TEMPERATURE : low +12°C.
Very mild in the median altitude range. Snow surface refreezing high up : poor or non-existent.
SATURDAY AUGUST 27
Fairly sunny - sultry - late afternoon thundery shower risk
SKY CONDITION : clear in the morning - becoming partly cloudy or locally cloudy towards the latter part of the afternoon - some cumulus cloud growing over the massifs. Period of sunshine close to 75%.
PRECIPITATION : late afternoon thundery shower risk - rain-snow limit towards 4000 m.
WIND - aloft : SSW light - SW light to moderate.
TEMPERATURE : low +12 °C - high +29°C.
Uncertain.
SUNDAY AUGUST 28
Fairly sunny - sultry - late afternoon thundery shower risk
SKY CONDITION : clear in the morning - becoming partly cloudy or locally cloudy towards the latter part of the afternoon - some cumulus cloud growing over the massifs. Period of sunshine close to 75%.
PRECIPITATION : late afternoon thundery shower risk - rain-snow limit towards 3800 m.
WIND - aloft : WSW -> WNW light to moderate.
TEMPERATURE : low +12°C - high +28°C.
Thunderstorm risk seems lower than on Saturday evening. Uncertain.
EXTENDED OUTLOOK UNTIL WEDNESDAY AUGUST 31

Monday : increasing southwest high up ‑ little thundery disturbance probably crossing over in the afternoon. Tuesday and Wednesday : fairly sunny ‑ warmer than seasonal average.

Forecast reliability : fairly good until Friday - poor thereafter.

ReportsAs a reminder, today in Chamonix, the sun rises at 06:45:45 and goes down at 20:22:59.
45.55 N 6.51 E - Altitude 1040 m
25 August 07:00
Temperature +10°C
Relative humidity 80%
Wind NE 3 km/h
Sea level pressure 1022 hpa - steady
Pressure at 1042 m 905 mb
Precipitation last 6h 0.0 mm
Skies clear
Visibility 95000 m
Altitude 3845 m
25 August 07:00
Temperature +4°C
Wind NE 5 km/h
Altitude 2250 m
25 August 06:00
Snow depth 0 cm
Wind 0 km/h
Gusts 5 km/h
Temperature +16°C