CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Matsuo Bashō
To raging winds
Companions : —
The single moon
ISSUED AT 08:45 SATURDAY MAY 08
VALID FROM : SATURDAY MAY 08 -- UNTIL : THURSDAY MAY 13 2021

GENERAL SYNOPSIS
Altitude high pressure push from Northwest Africa to the Alps. This is a mild air spur in the median-high altitude range which is drifting east. • Simultaneously, very deep surface low (967 hpa) approaches Ireland from west-southwest, which will contribute to shape a foehn gradient along the Alpine Range by this evening, then to thightening it considerably from west by Sunday evening. • Therefore, after pleasantly sunny spring-like condition this Saturday, it is advised to have concern about a strong foehn spell in the northern valleys, between Sunday afternoon and Monday noon. • That fœhn spell is expected to ending towards Monday afternoon upon cossing of the above mentioned cold front.
TODAY - SATURDAY MAY 08
Fair weather - noticeably milder in the median altitude range - wind decreases further
SKY CONDITION : clear or partly cloudy. Period of sunshine close to 85%.
PRECIPITATION : none.
WIND - ground level : SW light - locally light to moderate.
WIND - mid mountain : mainly W - moderate -> light to moderate.
WIND - high mountain : NW moderate to strong -> W light to moderate.
TEMPERATURE : low +1°C - high +19°C.
ISOTHERM 0°C : 2700 -> 3500 m.
ISOTHERM -10°C : 4800 -> 5100 m.
OVERNIGHT
Clear night - thin high cloud at times - fœhn puffs likely towards dawn
SKY CONDITION : clear or partly cloudy - thin high cloud crossings - iso 0°C towards 3600 m.
PRECIPITATION : none.
WIND - aloft : W light to moderate -> SW moderate - fœhn puffs already possible towards the end of the night in the Upper Valley.
TEMPERATURE : low +6°C.
SUNDAY MAY 09
Fairly sunny and warm - moderate foehn with cloud running over from Italy
SKY CONDITION : clear or partly cloudy - thin high cloud crossings - foehn cloud locally running over from Italy. Period of sunshine close to 75%.
PRECIPITATION : none.
WIND - aloft : SW moderate -> SSW strong - moderate foehn, becoming strong towards the evening.
TEMPERATURE : low +8 °C - high +22°C.
MONDAY MAY 10
Sunny outbreak early in the morning, then shower crossings - foehn, severe gale risk
SKY CONDITION : cloudy with sunny spells early in the morning - becoming mostly cloudy due to foehn cloud occasionally running over from Italy. Period of sunshine close to 25%.
PRECIPITATION : shower running over from Italy - rain-snow limit towards 2500-2600 m.
WIND - aloft : SW strong to gale force - occasionally severe gale - strong foehn, or even locally severe gale at first in the valley.
TEMPERATURE : rising.
EXTENDED OUTLOOK UNTIL THURSDAY MAY 13 2021

Tuesday : unsettled - often mostly cloudy with shower crossings, fairly active in the afternoon - fleeting sunny outbreak cannot be ruled out, especially towards noon. Wednesday : uncertain - disturbance moving away eastward - early morning shower still possible, then sunny spells spreading. Thursday : very uncertain - slightly low pressure area with low gradient towards the Alps - changeable between sunny outbreaks and noticeable cloud increase during the afternoon, possibly triggering isolated showers.

Forecast reliability : broadly fairly good until Monday, yet quite uncertain in detail, especially regarding chronology.

ReportsAs a reminder, today in Chamonix, the sun rises at 06:07:01 and goes down at 20:50:52.
Chamonix - ville
45.55 N 6.51 E - Altitude 1020 m
May 08 08:00
Temperature +3.8°C
Relative humidity 93%
Wind 0 km/h
Sea level pressure 1018 hpa - rising
Pressure at 1042 m 900 mb
Precipitation last 6h 0 mm
Skies high cloud patches
Visibility 95000 m
Altitude 3845 m
May 08 07:00
Temperature -5°C
Wind WNW 40-45 km/h
Altitude 2250 m
May 08 07:00
Snow depth 227 cm
Wind SW 13 km/h
Gusts 21 km/h
Temperature +1.2°C