CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Matsuo Bashō
Higher than the lark
Resting in the sky
Of the mountain pass
ISSUED AT 08:55 MONDAY JULY 26 2021
VALID FROM : MONDAY JULY 26 -- UNTIL : FRIDAY JULY 30 2021

GENERAL SYNOPSIS
High 1025-1016 hpa, Azores to French Basque Country, in a trend towards strengthening this Monday. • Low 1006-1008 hpa north to south of North Sea, linked to cut-off currently whirling around Calais. • In the southeast fringes of that barely evolving pattern, Alpine Range will remain embedded in unstable and moderately humid southwest puffs during the main part of the week, with convection causing more or less diurnal evolution from sunny morning until evening shower with possible local thunderstorm, depending on fluctuations of that Azores high ridge.
TODAY - MONDAY JULY 26
Unstable - frequent morning sunny outbreaks - thundery shower likely in the afternoon
SKY CONDITION : millefeuille of cloud in the median altitude range early this morning, partly dispelling under direct sunshine - then convection will make cumulus bulky above the slopes during the afternoon, shaping cloudy or locally mostly cloudy skies. Period of sunshine close to 40%.
PRECIPITATION : possible isolated shower from the middle of the day, probably becoming more frequent in the first part of the afternoon, maybe with local thunderstorm - rain-snow limit towards 3200 m - possible water amount in the valley : 3-6 mm.
WIND - ground level : calm -> SW light -> variable very light.
WIND - mid mountain : SW light -> WSW light to moderate - occasionally moderate early in the afternoon.
WIND - high mountain : SW light to moderate -> WSW moderate.
TEMPERATURE : low +12°C - high +22°C.
ISOTHERM 0°C : 3500 -> 3600 m.
ISOTHERM -10°C : 5000 -> 5300 m.
OVERNIGHT
Windy skies clearing high up, yet somewhat more cloudy in the median altitude range
SKY CONDITION : skies clearing fairly soon high up by nightfall - median altitude cloud patches may presist along the slopes - good radiation above 3300 m, therefore fairly good snow surface re-freezing - iso 0°C towards 3600 m.
PRECIPITATION : probably none.
WIND - aloft : WSW moderate - occasionally moderate to strong.
TEMPERATURE : low +12°C.
TUESDAY JULY 27
Fairly sunny in the morning - becoming cloudy with sunny spells - windy high up
SKY CONDITION : partly cloudy in the morning - becoming cloudy to cloudy with sunny spells in the afternoon, due to cumulus cloud development above the massifs. Period of sunshine close to 55%.
PRECIPITATION : none.
WIND - aloft : WSW moderate to strong.
TEMPERATURE : low +11 °C - high +24°C.
WEDNESDAY JULY 28
Uncertain - scattered shower at first - sunny spells in the afternoon - windy high up
SKY CONDITION : cloudy or locally mostly cloudy in the morning - fair sunny spells spreading out later among afternoon cumulus patches. Period of sunshine close to 50%.
PRECIPITATION : scattered shower in the course of the morning - rain-snow limit towards 3500 m - possible water amount in the valley : 2-3 mm.
WIND - aloft : WSW moderate to strong.
TEMPERATURE : rising lows.
EXTENDED OUTLOOK UNTIL SATURDAY JULY 31 2021

Thursday : fairly sunny, becoming sultry in the afternoon - evening shower risk - occasionally fairly strong southwest high up. Friday : uncertain - often mostly cloudy with showers, more fequent and heavier in the afternoon - west-southwest high up, fairly strong. Saturday : very uncertain - cloudy with sunny spells in the morning - mainly cloudy with showers later - west-southwest high up, fairly strong, probably decreasing later.

Forecast reliability : fairly good until Wednesday.

ReportsAs a reminder, today in Chamonix, the sun rises at 06:09:04 and goes down at 21:09:03.
Chamonix - ville
45.55 N 6.51 E - Altitude 1020 m
July 26 08:00
Temperature +13.9°C
Relative humidity 88%
Wind NE 5 km/h
Sea level pressure 1015 hpa - rising slowly
Pressure at 1042 m 896 mb
Precipitation last 6h 0.0 mm
Skies cloudy
Visibility 15000 m
Altitude 3845 m
July 26 07:00
Temperature -1.6°C
Wind SW 10-65 km/h
Altitude 2250 m
July 26 07:00
Snow depth -- cm
Wind SW 3 km/h
Gusts 9 km/h
Temperature +7.2°C