CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Takahama Kyoshi
The snake flees—
But the eyes that peered at me
Remain in the weeds
ISSUED AT 19:20 ON SATURDAY MAY 20, 2017
VALID FROM : SATURDAY MAY 20 -- UNTIL : FRIDAY MAY 26 2017

GENERAL SYNOPSIS
Azores high ridge extending 1023-1024 hpa, Southwestern France to Northern Alps and further to Southwestern Germany. • That ridge will be isolating as a high cell over France by Sunday, which will be drifting over Northern Germany and the Southern Scandinavian by Monday, thus leaving space for a slightly lower pressure field with almost no gradient over the Alps. • Therefore, after a fair sunny Sunday, already warm in the afternoon, Monday will be changeable, with high cloud crossing over and large cumulus growing over the massifs in the afternoon. • Another Azorean high pressure area will be strengthening again over Biscaye towards Tuesday before refocusing over the British Isles by Wednesday, ensuring a fairly sunny period until Thursday at least, especially as it will be reinforced by an African originated altitude high ridge.
SATURDAY EVENING MAY 20 - AND OVERNIGHT
Clearing skies - cold in the valley - getting milder high up
SKY CONDITION : evening cloud dispelling fairly soon - then, clear.
PRECIPITATION : none.
WIND - ground level : variable or NE light.
WIND - mid mountain : NE -> variable light.
WIND - high mountain : NNW moderate -> moderate to strong -> NW light to moderate.
TEMPERATURE : low +2°C.
ISOTHERM 0°C : 2400 -> 3300 m.
ISOTHERM -10°C : 4100 -> 4900 m.
Temperature inversion towards 1200 m by dawn.
TOMORROW - SUNDAY MAY 21
Fair weather - getting noticeably milder in the median altitude range
SKY CONDITION : clear or partly cloudy - thin high cloud from the west towards the evening. Period of sunshine close to 90%.
PRECIPITATION : none.
WIND - ground level : variable or SW light.
WIND - mid mountain : variable -> SW light.
WIND - high mountain : NW -> WNW light to moderate.
TEMPERATURE : low +1°C - high +21°C.
ISOTHERM 0°C : 3300 -> 3600 m.
ISOTHERM -10°C : 4900 -> 5000 m.
Same kind of weather over the bordering Valais and in the Upper Aosta Valley.
SUNDAY TO MONDAY NIGHT - MAY 21 TO 22
Skies often hazy due to high cloud passings - mild in the median altitude range
SKY CONDITION  : partly cloudy - thin high cloud crossing over.
PRECIPITATION : none.
WIND - aloft : WNW light to moderate.
TEMPERATURE : low +5°C.
Uncertain.
MONDAY MAY 22
Fairly sunny - warm and locally cloudy in the afternoon
SKY CONDITION : partly cloudy - cloudy at times in the afternoon - thin high cloud passings all along the day - cumulus cloud growing over the massifs in the afternoon. Period of sunshine close to 75%.
PRECIPITATION : none.
WIND - aloft : WNW -> NW light to moderate.
TEMPERATURE : low +5 °C - high +22°C.
Uncertain.
TUESDAY MAY 23
Fairly sunny - warm and locally cloudy in the afternoon
SKY CONDITION : clear or partly cloudy - cloudy at times in the afternoon. Period of sunshine close to 75%.
PRECIPITATION : none.
WIND - aloft : N light to moderate -> NNE moderate.
TEMPERATURE : low +6°C - high +24°C.
Uncertain.
EXTENDED OUTLOOK UNTIL FRIDAY MAY 26

Wednesday : Fair weather - warm - cumulus over the massifs in the afternoon. Thursday : fairly sunny - hot in the valley ‑ warm in the median altitude range. Friday : sunny - barely slightly cooler. Outlook is still fairly uncertain for the three days.

Forecast reliability : fairly good until Sunday ‑ poor thereafter.

ReportsAs a reminder, today in Chamonix, the sun rises at 05:47:34 and goes down at 21:12:11.
45.55 N 6.51 E - Altitude 1040 m
27 may 07:00
Temperature +10°C
Relative humidity 82%
Wind 0 km/h
Sea level pressure 1021 hpa - rising slowly
Pressure at 1042 m 904 mb
Precipitation last 6h 0 mm
Skies partly cloudy
Visibility 90000 m
Altitude 3845 m
27 may 07:00
Temperature 0°C
Wind W 5 km/h
Altitude 2250 m
27 may 06:00
Snow depth 25 cm
Wind 0 km/h
Gusts 5 km/h
Temperature +10°C