CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Matsuo Bashō
Ah spring, spring
How great is spring !
and so on…
ISSUED AT 08:15 THURSDAY APRIL 15
VALID FROM : THURSDAY APRIL 15 -- UNTIL : TUESDAY APRIL 20 2021

GENERAL SYNOPSIS
Surface high pressure toping towards 1036 over North Sea, is drifting slowly towards Norway without weakening until Saturday; relative surface low 1010-1015 almost stationary over the Mediterranean. • High up : altitude cut-off, Northwestern Alps, expected to crossing over our Region southward bound in the afternoon and overnight. • As a result : fair sunny weather this morning; then increasing instability over the hours, favouring cumulus cloud growth in still unseasonably cold atmosphere. • Variation on the same pattern likely each afternoon until Sunday, depending on altitude stream backing west, or even southwest.
TODAY - THURSDAY APRIL 15
Sunny and cold in the morning - becoming milder and cloudy - decreasing wind high up
SKY CONDITION : clear early in the morning, becoming partly cloudy - locally cloudy or mostly cloudy in the afternoon with well grown cumulus cloud above median altitude range slopes. Period of sunshine close to 60%.
PRECIPITATION : possible snow flurries over the slopes in the afternoon under some cumulus cloud.
WIND - ground level : calm -> variable light -> occasionally SW.
WIND - mid mountain : calm -> variable light -> calm.
WIND - high mountain : NW moderate to strong -> W light to moderate.
TEMPERATURE : low -5°C - high +10°C.
ISOTHERM 0°C : 900 -> 1500 -> 1300 m.
ISOTHERM -10°C : 2500 -> 2700 -> 2600 m.
OVERNIGHT
Partly clearing skies - quite cold in the valley by dawn
SKY CONDITION : evening cumulus cloud dispelling, yet cloud patches persistently running over from south - iso 0°C dropping towards 900 m.
PRECIPITATION : none.
WIND - aloft : W -> SW light to moderate.
TEMPERATURE : low -2°C.
FRIDAY APRIL 16
Partly sunny - cold in the morning - getting somewhat milder in the afternoon
SKY CONDITION : partly cloudy to cloudy - bulky cumulus cloud growing above median altitude range slopes in the afternoon. Period of sunshine close to 60%.
PRECIPITATION : none.
WIND - aloft : SW light to moderate -> SSW light.
TEMPERATURE : low -3 °C - high +10°C.
SATURDAY APRIL 17
Uncertain - fair weather likley - getting noticeably milder - cumulus cloud over the massif
SKY CONDITION : clear, then partly cloudy - cumulus cloud growing above median altitude range slopes in the afternoon. Period of sunshine close to 80%.
PRECIPITATION : none.
WIND - aloft : NE light - occasionally light to moderate.
TEMPERATURE : dropping lows - rising highs.
EXTENDED OUTLOOK UNTIL TUESDAY APRIL 20 2021

Sunday : fairly sunny morning - locally mostly cloudy in the afternoon with cumulus cloud spreading while getting bulky - fairly strong northeast high up in the morning. Monday : partly sunny - locally cloudy in the afternoon with cumulus cloud spreading - northerly stream high up, fairly strong at times. Tuesday : uncertain - fair weather likely - cumulus cloud growing over the massifs in the afternoon - getting slightly milder.

Forecast reliability : fairly good until Saturday - uncertain thereafter.

ReportsAs a reminder, today in Chamonix, the sun rises at 06:43:12 and goes down at 20:21:08.
Chamonix - ville
45.55 N 6.51 E - Altitude 1020 m
April 15 08:00
Temperature -2.9°C
Relative humidity 77%
Wind 0 km/h
Sea level pressure 1018 hpa - dropping slightly
Pressure at 1042 m 900 mb
Precipitation last 6h 0.0 mm
Skies clear
Visibility 65000 m
Altitude 3845 m
April 15 07:00
Temperature -18°C
Wind NW 30 km/h
Altitude 2250 m
April 15 07:00
Snow depth 175 cm
Wind W 4 km/h
Gusts 12 km/h
Temperature -11.7°C