CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Tan Taïgi
Sweeping up
And then not –
Fallen leaves –
ISSUED AT 08:30 THURSDAY OCTOBER 29
VALID FROM : THURSDAY OCTOBER 29 ‑‑ UNTIL : TUESDAY NOVEMBER 3 2020

GENERAL SYNOPSIS
Former hurricane « epsilon », currently southwest of Iceland (965 hpa), is still driving a powerful unsettled northwest stream Atlantic to Alps, this Thursday morning. • Southwest tip of an occlusion embedded in that stream is affecting our Region, triggering light to moderate precipitation until noon or so. • Simultaneously, high pressure cell is inflating, from Spain (1027 towards the evening), which will get reinforced by a Saharan originated altitude high pressure spur. • This will cause fairly sunny, stable and very mild weather, Friday until Monday, especially in the median altitude range. • Some deterioration likely by Tuesday, cooler with shower risk.
TODAY - THURSDAY OCTOBER 29
Some shower, still, this morning, then dry with sunny spells ‑ gale winds high up
SKY CONDITION : overcast, ceiling towards 1800‑2000 m, then mostly cloudy ‑ fleeting sunny spells at first in the afternoon, then more widespread ‑ partly cloudy in the evening. Period of sunshine close to 25%.
PRECIPITATION : scattered shower, becoming isolated over the morning hours ‑ rain‑snow limit towards 1900 m, rising ‑ low accumulation.
WIND - ground level : SSW ‑> SW light.
WIND - mid mountain : WSW moderate ‑> NW light.
WIND - high mountain : WNW gale ‑> NW strong.
TEMPERATURE : low +6°C - high +11°C.
ISOTHERM 0°C : 2200 ‑> 2800 m.
ISOTHERM -10°C : 4400 ‑> 5100 m.
OVERNIGHT
Stong winds will sweep cloud high up ‑ slight stratus cloud risk in the valley
SKY CONDITION : partly cloudy, then clear high up ‑ some low cloud likely to sticking to the slopes ‑ iso 0°C rising up towards 3300 m.
PRECIPITATION : none.
WIND - aloft : NW strong.
TEMPERATURE : low +3°C.
FRIDAY OCTOBER 30
Fair weather with great visibility ‑ cold in the morning ‑ very mild later
SKY CONDITION : still some thin high cloud in the morning ‑ probably outstandingly clear in the afternoon. Period of sunshine close to 90%.
PRECIPITATION : none.
WIND - aloft : NW strong ‑> NNW moderate.
TEMPERATURE : low +1 °C - high +18°C.
SATURDAY OCTOBER 31
Fair weather ‑ morning frost ‑ almost warm in the afternoon
SKY CONDITION : clear or partly cloudy ‑ thin high cloud at times. Period of sunshine close to 80%.
PRECIPITATION : none.
WIND - aloft : WSW light to moderate ‑> moderate.
TEMPERATURE : slightly dropping lows ‑ slightly rising highs.
EXTENDED OUTLOOK UNTIL TUESDAY NOVEMBER 3 2020

Sunday : morning frost until direct sunshine in the valley, then skies getting veiled high up over the hours. Monday : persistent high context, though altitude thalweg approaches from west ‑ often hazy sunshine therefore ‑ rather light altitude southwest stream, still very mild. Tuesday : uncertain ‑ thalweg’s tip might be cutting off towards Bay of Biscaye, thus allowing for remaining high pressure field over the Alpine Range, and causing fairly sunny and mild morning, then colder and often cloudy condition in the afternoon, without precipitation.

Forecast reliability : fairly good until Saturday ‑ poor thereafter.

sommet
ReportsAs a reminder, today in Chamonix, the sun rises at 07:09:57 and goes down at 17:22:25.
Chamonix - ville
45.55 N 6.51 E - Altitude 1020 m
October 29 - 08:00
Temperature +7°C
Relative humidity 93%
Wind 0 km/h
Sea level pressure 1024 hpa - rising
Pressure at 1042 m 902 mb
Precipitation last 6h 7.2 mm
Skies overcast - ceiling towards 2000 m
Visibility 4000 m
Altitude 3845 m
October 29 - 07:00
Temperature -9°C
Wind WNW 50/80 km/h
Altitude 2250 m
October 29 - 07:00
Snow depth 4 cm
Wind SW 22 km/h
Gusts 44 km/h
Temperature -1.3°C