CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Matsuo Bashō
Heat shimmer
Rising from the shoulder
My paper robe
ISSUED AT 09:30 THURSDAY MAY 19 2022
VALID : THURSDAY 19 -- TUESDAY MAY 24 2022

GENERAL SYNOPSIS
Hot SW stream, expected to becoming unstable this Thursday, between extended low pressure system, 980 hpa towards North Atlantic Ocean's center, and the Central European High which is currently toping towards 1030 hpa towards Hungary and linked to Saharan originated altitude high pressure ridge up to SW Baltic Sea. • Such a moderate diurnal evolution pattern is likely to shape randomly spread rainy-thundery cells as of late morning, yet still possible by nightfall. • Heat peak towards 31°C in the valley by Friday, in a less unstable atmosphere, thus considerably lowering thunderstorm risk; it might be however resuming during the night to Saturday.
TODAY - THURSDAY MAY 19
Fairly sunny - high heat - thundery shower risk as of late morning
SKY CONDITION : partly cloudy in the morning, high cloud patches slowly running over from W - cumulus cloud growing soon above the massifs, i.e. before noon. Period of sunshine close to 55%.
PRECIPITATION : thundery shower risk arises before noon - rain-snow limit towards 3500 m, dropping towards 3300 m.
WIND - ground level : variable -> SW light.
WIND - mid mountain : SW moderate -> WSW light to moderate.
WIND - high mountain : SW -> W light to moderate - occasionally moderate.
TEMPERATURE : low +8°C - high +27°C.
ISOTHERM 0°C : 3800 -> 3700 -> 3800 m.
ISOTHERM -10°C : 5200 -> 5300 m.
OVERNIGHT
Thundery shower likely at first, then clearing skies - cool in the valley by dawn
SKY CONDITION : cloud patches keep crossing over until the middle of the night, then gradually dispelling - fairly good snow surface re-freezing high up towards the latter part - iso 0°C towards 3900 m.
PRECIPITATION : none.
WIND - aloft : W light to moderate - occasionally WNW moderate.
TEMPERATURE : low +8°C.
FRIDAY MAY 20
Sunny on the whole - maybe hottest day of this spring - more stable than previously
SKY CONDITION : partly cloudy in the morning, thin high cloud as extended patches - cumulus cloud growing moderately above the slopes in the afternoon. Period of sunshine close to 75%.
PRECIPITATION : probably none.
WIND - aloft : W light to moderate -> moderate to strong - locally WNW near gale at times.
TEMPERATURE : low +7 °C - high +31°C.
SATURDAY MAY 21
Sunny - slightly cooler than previously - moderate convection, cloud growth as well
SKY CONDITION : clear or partly cloudy in the morning - locally cloudy above the massifs in the afternoon due to cumulus cloud growth. Period of sunshine close to 75%.
PRECIPITATION : late afternoon shower slight risk - rain-snow limit towards 3300 m.
WIND - aloft : NW strong - decreasing somewhat towards the evening.
TEMPERATURE : dropping lows.
EXTENDED OUTLOOK UNTIL TUESDAY MAY 24 2022

Sunday : fairly sunny, hot and already somewhat unstable at times, thus increasing shower risk in the evening - fairly strong NW high up, backing WSW while decreasing. Monday : uncertain - becoming unsettled, with possible severe gale high up, mainly W - some fair sunny outbreaks likely in the morning, then shower crossing over with snow limit towards 3000-3200 m. Tuesday : uncertain - unstable tail driving considerably cooler air (± 21°C) from W - fair sunny spells likely towards the middle of the day, then resuming showery or even thundery risk during the afternoon.

Forecast reliability : fairly good until Sunday - poor thereafter.

ReportsAs a reminder, today in Chamonix, the sun rises at 05:55:33 and goes down at 21:02:30.
Chamonix - ville
45.55 N 6.51 E - Altitude 1020 m
May 19, 2022 08:00
Temperature +15.1°C
Relative humidity 82%
Wind 0 km/h
Sea level pressure 1030 hpa - steady
Pressure at 1042 m 912 mb
Precipitation last 6h 5-15 mm
Skies partly cloudy
Visibility 80 000 m
Altitude 3845 m
May 19, 2022 08:00
Temperature +0.3°C
Wind WSW 10-30 km/h
Altitude 2250 m
May 19, 2022 08:00
Snow depth 26 cm
Wind 0 km/h
Gusts VAR 10 km/h
Temperature +9.5°C