CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST
ISSUED AT 08:30 THURSDAY MAY 13
VALID FROM : THURSDAY MAY 13 -- UNTIL : TUESDAY MAY 18 2021
Of the raindrops
Grown older as well
Low pressure on the whole over Western Europe, with two minima shaping weather of the Alpine Range, Atlantic one towards Central English Channel (1004), and Mediterranean on in the Northern Gulf of Genoa (1006). • Cold front linked to the Channel one is currently crossing over our Region. It is about to disintegrating and will be triggering only light rain until the middle of the day, which will turn thereafter into more and more scattered showers. Rain-snow limit may drop locally towards 1600 m. • Weak high pressure push from Azores overnight and on Friday will probably cause fairly sunny improvement by Friday morning, while high instability will make mostly cloudy afternoon. • Occasionally rainy deterioration as of Saturday afternoon, upon income of fairly deep low west of Ireland.
TODAY - THURSDAY MAY 13
SKY CONDITION : mostly cloudy by dawn, then fair morning sunny oubreaks - convection make cumulus cloud grow over the afternoon hours. Period of sunshine close to 35%.
PRECIPITATION : showery from west in the morning - rain-snow limit towards 1600 m - expected snowfall towards 1800 m : ≤ 5 cm.
WIND - ground level : SW very light.
WIND - mid mountain : WSW light.
WIND - high mountain : WSW light to moderate - occasionally NW.
TEMPERATURE : low +5°C - high +13°C.
ISOTHERM 0°C : 1700 -> 2100 m.
ISOTHERM -10°C : 3500 m.
SKY CONDITION : cloudy with clear spells, becoming partly cloudy - iso 0°C dropping towards 1900 m.
PRECIPITATION : none.
WIND - aloft : mainly W - light to moderate -> light.
TEMPERATURE : low +2°C.
FRIDAY MAY 14
SKY CONDITION : partly cloudy early in the morning - becoming cloudy with sunny spells by noon, then locally mostly cloudy in the afternoon due to cumulus cloud growth. Period of sunshine close to 40%.
PRECIPITATION : moderate showery spell early in the afternoon - possible remaining light rain along the slopes thereafter - rain-snow limit towards 1600 m - expected snowfall towards 1800 m : ± 5 cm.
WIND - aloft : mainly W - light or occasionally light to moderate.
TEMPERATURE : low +1 °C - high +12°C.
SATURDAY MAY 15
SKY CONDITION : cloudy with fleeting sunny spells in the morning - becoming overcast in the afternoon. Period of sunshine close to 15%.
PRECIPITATION : light and scattered shower early in the afternoon - turning into light rain - rain-snow limit towards 1700 m - expected snowfall towards 1800 m : ± 5 cm.
WIND - aloft : WNW moderate to strong -> W strong.
TEMPERATURE : dropping slightly.
EXTENDED OUTLOOK UNTIL TUESDAY MAY 18 2021
Sunday : slightly low pressure field in the SE fringes of the Irish minimum - after changeable spell between sunny spells and scattered light rain of the warm sector, more considerable rainy deterioration upon approach of the cold front in the afternoon - mainly W, strong high up. Monday : uncertain - the Alpine Range is expected to becoming an evident boundary layer between Atlantic low area northward and Mediterranean high area southward - unstable tail following previous night's disturbance shall trigger shower along northern slope while Italian one will remain sunny - mainly WNW, occasionally fairly strong high up. Tuesday : very uncertain - yet in a trend towards improving in a westerly to northwesterly stream, fairly strong high up, which drives humid waves likely to triggering some showers.
Forecast reliability : fairly good until Friday.