CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Tomiyasu Fūsei
There's nothing
He doesn't know—
The cat on the stove
ISSUED AT 19:40 ON WEDNESDAY APRIL 23, 2014
VALID FROM : WEDNESDAY APRIL 23 -- UNTIL : TUESDAY APRIL 29 2014

GENERAL SYNOPSIS
Low gradient pattern with fairly high pressure field (1016-1019 hpa) over France, the Alps and the Mediterranean. Therefore, on Thursday : sunny in the morning, then cloud increase possibly triggering scattered showers spreading randomly later in the afternoon. Weakening pressure field from Thursday evening expected to driving a more noticeable deterioration by Friday. Much improved on Saturday. Fairly deep low possibly settling down over Ireland by Sunday, driving its linked disturbance slowly over the Alps, thus possibly causing heavy precipitation during the main part of the day.
WEDNESDAY EVENING APRIL 23 - AND OVERNIGHT
Improving early in the night - dry and cool by dawn
SKY CONDITION : mostly cloudy to overcast evening - becoming cloudy with clear spells - then clear or partly cloudy towards the latter part of the night.
PRECIPITATION : thundery shower in the evening, vanishing quickly - rain-snow limit towards 2500 m - dry later.
WIND - ground level : variable light.
WIND - mid mountain : variable light.
WIND - high mountain : W light -> WSW light to moderate.
TEMPERATURE : low +4°C.
ISOTHERM 0°C : 2600 m.
ISOTHERM -10°C : 4100 m.
Uncertain.
TOMORROW - THURSDAY APRIL 24
Sunny morning ‑ cloudy with shower risk in the afternoon - very mild
SKY CONDITION : clear or partly cloudy in the morning - high cloud coming in from the southwest in the afternoon while cumuls cloud are growing over the massifs. period of sunshine close to 75%.
PRECIPITATION : shower risk in the afternoon - rain-snow limit towards 2600 m.
WIND - ground level : variable light - light to moderate thermal breeze early in the afternoon.
WIND - mid mountain : variable -> SE light.
WIND - high mountain : WSW -> SSW light to moderate.
TEMPERATURE : low +4°C - high +20°C.
ISOTHERM 0°C : 2600 -> 3000 -> 2700 m.
ISOTHERM -10°C : 4100 -> 4300 -> 4000 m.
Uncertain.
THURSDAY TO FRIDAY NIGHT - APRIL 24 TO 25
Cloudy deterioration from the southwest - probably dry
SKY CONDITION  : cloudy, becoming mostly cloudy - cumulus cloud vanishing - thickening high cloud.
PRECIPITATION : probably none.
WIND - aloft : SSW light to moderate -> light.
TEMPERATURE : low +6°C.
Uncertain.
FRIDAY APRIL 25
Unsettled while getting cooler - mainly cloudy - becoming rainy
SKY CONDITION : cloudy to mostly cloudy early in the morning - possible fleeting sunny spells - becoming quickly overcast. Period of sunshine close to 5%.
PRECIPITATION : scattered shower starting up towards the middle of the day, then changing to continuous rain, at times moderate towards the latter part of the afternoon - rain-snow limit towards 2200 m, dropping towards 1800 m at night.
WIND - aloft : S -> NE faible.
TEMPERATURE : low +6 °C - high +12°C.
Very uncertain.
SATURDAY APRIL 26
Cloudy with bright sunny spells ‑ probably no precipitation
SKY CONDITION : cloudy with sunny spells, probably brighter towards the middle of the day - cumulus cloud growing over the slopes during the afternoon. Period of sunshine close to 65%.
PRECIPITATION : none.
WIND - aloft : N light -> SW light to moderate.
TEMPERATURE : low +4°C - high +16°C.
Uncertain.
EXTENDED OUTLOOK UNTIL TUESDAY APRIL 29 2014

Sunday : very active disturbance crossing over ‑ heavy precipitation starting up early in the morning. Monday : unsettled and cool ‑ few sunny spells ‑ showers. Tuesday : Unsettled - morning sunny spells - showers later. Very uncertain throughout the three days..

Forecast reliability : poor.

ReportsAs a reminder, today in Chamonix, the sun rises at 06:29:58 and goes down at 20:31:13.
45.55 N 6.51 E - Altitude 1040 m
24 April 08:00
Temperature +4°C
Relative humidity 100%
Wind 0 km/h
Sea level pressure 1020 hpa - steady
Pressure at 1042 m 901 mb
Precipitation last 6h 0.0 mm
Skies clear
Visibility 55000 m
Altitude 3845 m
24 April 08:00
Temperature -8°C
Wind -- km/h
Altitude 2250 m
24 April 08:00
Snow depth 60 cm
Wind 5 km/h
Gusts 10 km/h
Temperature 0°C