CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Masaoka Shiki
A mountain village
Under the piled-up snow
The sound of water
ISSUED AT 19:05 ON MONDAY FEBRUARY 27, 2017
VALID FROM : MONDAY FEBRUARY 27 2017 -- UNTIL : SUNDAY MARCH 05 2017

GENERAL SYNOPSIS
Very deep, extended and complex low system whirling around Scotland with a minimum 970 hpa toward Faroes; it contributes to a fœhn wind gradient along the high massifs with the remaining fairly high pressure field over Northern Italy, which will resolve in the first part of the night. • The cold front linked to that low system will be reaching our region towards the latter part of the night, triggering moderate precipitation or fairly heavy at times, allowing for snow in the valley by Tuesday evening, and causing a severe westerly gale high up as well. • Further outlook, still uncertain in detail, shows a series of westerly disturbances following each other until the first days of next week.
MONDAY EVENING FEBRUARY 27 - AND OVERNIGHT
Fœhn wind trend at first - becoming rainy - gale high up
SKY CONDITION : becoming cloudy in the first part of the night - thickening high cloud - overcast towards the middle of the night.
PRECIPITATION : starting up toward the latter part of the night - moderate, then fairly strong at times before dawn - rain-snow limit towards 1500 m, dropping - expected snowfall towards 1800 m : 10-20 cm, windblown.
WIND - ground level : variable light to moderate with fœhn wind puffs -> SW light.
WIND - mid mountain : SW moderate - WSW strong at times.
WIND - high mountain : SW strong -> WSW strong to gale force.
TEMPERATURE : low +3°C.
ISOTHERM 0°C : 1900 -> 1700 m.
ISOTHERM -10°C : 3600 -> 3300 m.
Uncertain, swift evolving phenomenon.
ROAD CONDITION  : @ 16:00, roadways becoming snow covered above 1000 m.morelive precipitation radar over the Alps
TOMORROW - TUESDAY FEBRUARY 28
Bad weather - snow in the valley towards the evening - severe westerly gale high up
SKY CONDITION : overcast. Period of sunshine close to 0%.
PRECIPITATION : moderate on the whole - light and scattered towards the middle of the day - fairly strong at times in the afternoon - rain-snow limit dropping towards 1000 m - expected snowfall towards 1800 m : 20-30 cm, windblown.
WIND - ground level : SW light - moderate at times.
WIND - mid mountain : SW moderate -> WSW moderate to strong - strong at times.
WIND - high mountain : WSW strong to gale force -> moderate to strong.
TEMPERATURE : low +2°C - high +5°C.
ISOTHERM 0°C : 1700 -> 1200 m.
ISOTHERM -10°C : 3300 -> 2400 m.
Uncertain, swift evolving phenomenon.
TUESDAY TO WEDNESDAY NIGHT - MARCH 28 TO 01
Bad weather - snow showers - strong wind high up
SKY CONDITION  : mostly cloudy to overcast.
PRECIPITATION : eventually fairly strong at first - becoming light to moderate - rain-snow limit towards 800 m - expected snowfall towards 1800 m : 15-25 cm, windblown.
WIND - aloft : WSW moderate to strong -> WNW strong.
TEMPERATURE : low -2°C.
Very uncertain.
WEDNESDAY MARCH 01
Scattered snow showers, then getting milder - gale high up, decreasing later
SKY CONDITION : mostly cloudy in the morning and towards the latter part of the afternoon - some fleeting sunny spells in the mean time. Period of sunshine close to 20%.
PRECIPITATION : scattered snow showers in the morning - scattered rain showers in the afternoon - rain-snow limit rising up towards 1500 m - expected snowfall towards 1800 m : ± 5 cm, windblown.
WIND - aloft : WNW strong -> NW gale -> WNW moderate to strong.
TEMPERATURE : low -2 °C - high +3°C.
Very uncertain.
THURSDAY MARCH 02
Changeable ‑ cloudy with sunny spells ‑ morning shower risk ‑ still windy high up
SKY CONDITION : mostly cloudy - becoming cloudy with sunny spells. Period of sunshine close to 40%.
PRECIPITATION : shower risk in the morning.
WIND - aloft : W moderate to strong -> moderate.
TEMPERATURE : low +2°C - high +8°C.
Very uncertain.
EXTENDED OUTLOOK UNTIL SUNDAY MARCH 05

Friday : cloudy with fair sunny spells ‑ dry ‑ unseasonably mild ‑ altitude flow backing south-southwest, strong high up ‑ fœhn wind getting up and possibly becoming strong towards the evening. Saturday : fairly weak disturbance crossing over in a fairly strong southwesterly high up. Sunday : changeable and colder - fleeting sunny spells - showers, may be snowy in the valley.

Forecast reliability : poor.

ReportsAs a reminder, today in Chamonix, the sun rises at 07:11:40 and goes down at 18:18:08.
45.55 N 6.51 E - Altitude 1040 m
28 February 08:00
Temperature +3°C
Relative humidity 85%
Wind SW 10 km/h
Sea level pressure 1001 hpa - rising
Pressure at 1042 m 887 mb
Precipitation last 6h 6.3 mm
Skies overcast - rain
Visibility 2500 m
Altitude 3845 m
28 February 07:00
Temperature -15°C
Wind WSW 100 km/h
Altitude 2250 m
28 February 06:00
Snow depth 30 cm
Wind 40 km/h
Gusts 80 km/h
Temperature -2°C