CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Matsuo Bashō
Travel-weary
How many days of this ?
Autumn winds
ISSUED AT 08:35 SATURDAY OCTOBER 01 2022
VALID : SATURDAY OCTOBER 01 -- THURSDAY OCTOBER 06 2022

GENERAL SYNOPSIS
Azores high ridge is about to resume, 1026, NE Ponta Delgada, up to Alpine Range (Sallanches, 1018 - Sion, 1018 - Innsbruck, 1015 hpa), countered by polar air thalweg which is currently reaching the Mediterranean S of Provence, yet expected to be repelled up to Black Sea by Sunday morning owing to NE spread of a subtropical altitude ridge. • Being driven by powerful NW, resulting disturbance will cross over our Region this Saturday, triggering light pre-frontal shower as of mid-morning, then featuring organized precipitation spell in the afternoon with barrier effect against W and N slopes of the high massifs until the latter part of the night. • Finally, 10-15 mm water likely in the valley, with rain-snow limit rising up 2300 ‑> 2800 m in the initial warm sector. • Improving thereafter, towards a 4-5 days period of fair weather next week, rather warm each afternoon.
TODAY - SATURDAY OCTOBER 01
Skies already veiled thick by dawn - becoming rainy - severe gale winds high up
SKY CONDITION : fleeting sunny outbreak, then thick cloud layer coming in, altostratus then stratus - overcast as of the middle of the day - ceiling towards 1800 m, dropping. Period of sunshine close to 10%.
PRECIPITATION : slight shower risk, early morning - rainy deterioration over the hours - rain-snow limit towards 2700-2800  m - possible water amount in the valley : 6-8 mm.
WIND - ground level : calm -> SW light - locally light to moderate.
WIND - mid mountain : W light -> WNW moderate to strong.
WIND - high mountain : NW strong -> severe gale.
TEMPERATURE : low +6°C - high +11°C.
ISOTHERM 0°C : 2900 -> 3300 m.
ISOTHERM -10°C : 3800 -> 4200 m.
OVERNIGHT
Continuous rain and very strong winds, yet improving slightly towards the latter part
SKY CONDITION : overcast in the first part of the night, ceiling towards 1800 m - becoming mostly cloudy towards the latter part, fleeting clear outbreaks already possible high up - iso 0°C towards 3300 m.
PRECIPITATION : light to moderate in the first part of the night, then becoming scarce and finally ending by dawn - rain-snow limit dropping towards 2600 m - possible water amount in the valley : 4-7 mm.
WIND - aloft : NW severe gale -> WNW strong.
TEMPERATURE : low +8°C.
SUNDAY OCTOBER 02
Sunny spells, then partly cloudy - NW very strong high up, decreasing - noticeably milder
SKY CONDITION : still locally cloudy in the first part of the morning, then clearing fairly widespread. Period of sunshine close to 65%.
PRECIPITATION : maybe some persistent drops by daybreak - else, none.
WIND - aloft : WNW strong -> severe gale -> NW moderate to strong.
TEMPERATURE : low +8 °C - high +17°C.
MONDAY OCTOBER 03
Sunny - cool in the morning, some low cloud patches - quite warm in the afternoon
SKY CONDITION : some low cloud might remain early in the morning, then clearing swiftly and widespread. Period of sunshine close to 85%.
PRECIPITATION : none.
WIND - aloft : NW moderate to strong -> NNW moderate.
TEMPERATURE : dropping slightly.
EXTENDED OUTLOOK UNTIL THURSDAY OCTOBER 06

Tuesday : after possible low cloud dispelling, fair weather sustained by light NNW flow high up, or occasionally light to moderate. Wednesday : fair sunny weather - W high up, light to moderate. Thursday : uncertain - fair weather likely, not much wind high up, maybe SW, to be confirmed.

Forecast reliability : fairly good until Sunday - poor thereafter.

ReportsAs a reminder, today in Chamonix, the sun rises at 07:31:24 and goes down at 19:12:41.
Chamonix - ville
45.55 N 6.51 E - Altitude 1030 m
October 01, 2022 08:00
Temperature +6.3°C
Relative humidity 95%
Wind 5 km/h
Sea level pressure 1019 hpa - rising
Pressure at 1042 m 902 mb
Precipitation last 6h 0 mm
Skies ceiling 2800 m
Visibility 10 000 m
Altitude 3845 m
October 01, 2022 08:00
Temperature -10.7°C
Wind WSW 25-55 km/h
Altitude 2250 m
October 01, 2022 08:00
Snow depth 18 cm
Wind W 15 km/h
Gusts 33 km/h
Temperature +1.8°C