CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Matsuo Bashō
Ah spring spring
How great is spring !
and so on
ISSUED AT 07:50 SUNDAY MAY 20
VALID FROM : SUNDAY MAY 20 ‑‑ UNTIL : FRIDAY MAY 25 2018

GENERAL SYNOPSIS
High 1027 hpa, Southern Sweden, lining up Russia to Northern Balkans by Tuesday. Lower pressure field with loose gradient over the Southern European, Alpine Range included, and the Mediterranean, weakening further from the southwest. • Light westerly to southerly stream over the Western Alps, providing some more humidity to an already fairly unstable air mass. This will favor noticeable diurnal evolution, causing cloud increase early in the afternoon and scattered thundery showers thereafter. • Same kind of weather expected to persisting next week, with a fluctuating level of instability which must be guessed from day to day, especially as a low system whirling around the Iberian Peninsula will propell new humidity waves towards the Western Alps, while a light fœhn trend will arise by the same time.
TODAY - SUNDAY MAY 20
Fair sunny spells in the morning ‑ scattered thundery shower in the afternoon
SKY CONDITION : clear or partly cloudy, then cloudy with sunny spells in the morning ‑ becoming mostly cloudy in the afternoon. Period of sunshine close to 45%.
PRECIPITATION : scattered thundery shower running over from the south fairly early in the afternoon ‑ rain‑snow limit towards 2700 m.
WIND - ground level : variable ‑> SW ‑> NE light fœhn.
WIND - mid mountain : SW ‑> S light.
WIND - high mountain : WSW ‑> SW light ‑ light to moderate at times.
TEMPERATURE : low +4°C - high +18°C.
ISOTHERM 0°C : 2800 ‑> 2900 m.
ISOTHERM -10°C : 4300 ‑> 4400 m.
OVERNIGHT
Variable ‑ fairly mild in the valley ‑ fœhn puffs
SKY CONDITION : Cloudy with clear spells.
PRECIPITATION : shower passing still likely in the first part of the night ‑ rain‑snow limit towards 2700 m ‑ dry later.
WIND - aloft : SW ‑> S light ‑ light to moderate at times ‑ light fœhn in the valley.
TEMPERATURE : low +7°C.
MONDAY MAY 21
Changeable, fœhn trend ‑ morning sunny spell ‑ thundery showers later
SKY CONDITION : cloudy with sunny spells in the morning ‑ becoming mostly cloudy in the afternoon. Period of sunshine close to 45%.
PRECIPITATION : thundery showers or thunderstorm in the afternoon ‑ rain‑snow limit towards 2700 m.
WIND - aloft : S ‑> SSE light to moderate ‑ morning fœhn puffs in the valley.
TEMPERATURE : low +8 °C - high +21°C.
TUESDAY MAY 22
Cloudy ‑ scarce sunny spells ‑ thundery trend, more pronounced in the afternoon
SKY CONDITION : cloudy to mostly cloudy ‑ some sunny spells in the morning. Period of sunshine close to 30%.
PRECIPITATION : thundery shower or thunderstorm from the southwest, more frequent in the afternoon ‑ rain‑snow limit towards 2700 m.
WIND - aloft : variable light.
TEMPERATURE : dropping slightly.
EXTENDED OUTLOOK UNTIL FRIDAY MAY 25 2018

Wednesday : partly sunny ‑ thundery shower risk, higher in the afternoon. Thursday : fairly sunny ‑ no precipitation. Friday : fairly sunny ‑ late afternoon shower slight risk.

Forecast reliability : poor.

ReportsAs a reminder, today in Chamonix, the sun rises at 05:53:35 and goes down at 21:04:42.
45.55 N 6.51 E - Altitude 1040 m
May 20 07:00
Temperature +4°C
Relative humidity 90%
Wind 0 km/h
Sea level pressure 1016 hpa - falling slowly
Pressure at 1042 m 900 mb
Precipitation last 6h 0.0 mm
Skies partly cloudy
Visibility 50000 m
Altitude 3845 m
May 20 07:00
Temperature -7°C
Wind SSW 15 km/h
Altitude 2250 m
May 20 06:00
Snow depth 204 cm
Wind 0 km/h
Gusts 5 km/h
Temperature +2°C