CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Matsuo Bashō
On a mountain path
Something might charm you
A wild violet
ISSUED AT 18:50 ON TUESDAY JULY 22, 2014
VALID FROM : TUESDAY JULY 22 -- UNTIL : MONDAY JULY 28 2014

GENERAL SYNOPSIS
Low 1007 hpa, Adriatic Sea, almost stationary, driving back an unsettled easterly stream over the Alps, gradually drier. Shower strip possibly crossing over the area at night, then slowly improving until Wednesday morning. Low gradient field with medium pressure setting up thereafter over France and the Mediterranean, and ruling for a while, favorable to typical summer condition with diurnal instability : sunny morning followed by cloudy afternoon with possible thundery shower later, which eventualtity is to be evaluated on a day to day basis.
TUESDAY EVENING JULY 22 - AND OVERNIGHT
Shower risk at first - becoming cloudy with clear spells
SKY CONDITION : mostly cloudy early in the night - becoming cloudy with clear spells - persistent fairly high cloud.
PRECIPITATION : light squall line possibly crossing over in the evening - dry later.
WIND - ground level : variable light or nil.
WIND - mid mountain : NE light - light to moderate at times.
WIND - high mountain : NE light to moderate -> E faible.
TEMPERATURE : low +11°C.
ISOTHERM 0°C : 4100 m.
ISOTHERM -10°C : 5700 m.
Same kind of weather over the Upper Aosta Valley.
TOMORROW - WEDNESDAY JULY 23
Fairly sunny in the morning ‑ warm and cloudy with shower risk in the afternoon
SKY CONDITION : partly cloudy in the morning - fairly high cloud - becoming cloudy with sunny spells - cumulus cloud growth in the afternoon. period of sunshine close to 50%.
PRECIPITATION : late afternoon thundery shower risk - rain-snow limit towards 3700 m.
WIND - ground level : variable light in the morning - light to moderate afternoon thermal breeze.
WIND - mid mountain : NE -> N light.
WIND - high mountain : E -> variable light.
TEMPERATURE : low +11°C - high +23°C.
ISOTHERM 0°C : 4100 -> 4200 -> 3900 m.
ISOTHERM -10°C : 5700 m.
Same kind of weather over the Upper Aosta Valley.
WEDNESDAY TO THURSDAY NIGHT - JULY 23 TO 24
Cloudy with clear spells - almost mild
SKY CONDITION  : locally mostly cloudy at times early in the night - becoming cloudy with clear spells.
PRECIPITATION : shower risk to be considered until the middle of the night - rain-snow limit towards 3500 m - dry later.
WIND - aloft : variable -> WNW light.
TEMPERATURE : low +11°C.
Uncertain.
THURSDAY JULY 24
Cloudy with sunny spells ‑ shower risk, higher in the afternoon
SKY CONDITION : cloudy with sunny spells - locally mostly cloudy in the afternoon due to cumulus cloudy growth. Period of sunshine close to 50%.
PRECIPITATION : thundery shower risk, higher towards the latter part of the afternoon - rain-snow limit towards 3400 m.
WIND - aloft : WNW light -> light to moderate.
TEMPERATURE : low +11 °C - high +22°C.
Uncertain.
FRIDAY JULY 25
Sunny in the morning ‑ warm and cloudy with sunny spells in the afternoon
SKY CONDITION : clear or partly cloudy in the morning - becoming cloudy with sunny spells - cumulus cloud growth in the afternoon. Period of sunshine close to 75%.
PRECIPITATION : late afternoon thundery shower slight risk - rain-snow limit towards 3500 m.
WIND - aloft : W -> SW light to moderate.
TEMPERATURE : low +10°C - high +24°C.
Very uncertain.
EXTENDED OUTLOOK UNTIL MONDAY JULY 28 2014

Saturday : uncertain - fairly weak disturbance likely to crossing over - thunderstorm risk. Sunday and Monday : more stable summer condition - fairly sunny - cumulus cloud over the massifs in the afternoon.

Forecast reliability : fairly good until Wednesday - poor thereafter.

ReportsAs a reminder, today in Chamonix, the sun rises at 06:05:22 and goes down at 21:12:40.
45.55 N 6.51 E - Altitude 1040 m
23 July 08:00
Temperature +12°C
Relative humidity 100%
Wind 0 km/h
Sea level pressure 1016 hpa - falling
Pressure at 1042 m 897 mb
Precipitation last 6h 0.5 mm
Skies partly cloudy - fog patches down in the valley
Visibility 500 / 70000 m
Altitude 3845 m
23 July 08:00
Temperature -1°C
Wind -- km/h
Altitude 2250 m
23 July 08:00
Snow depth 0 cm
Wind 5 km/h
Gusts -- km/h
Temperature +11°C