CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Yosa Buson
An axe strikes
The winter forest—
It smells to me
ISSUED AT 19:25 ON SATURDAY DECEMBER 20, 2014
VALID FROM : SATURDAY DECEMBER 20 -- UNTIL : FRIDAY DECEMBER 26 2014

GENERAL SYNOPSIS
High 1037 hpa, Biscaye, drifting east while weakening slightly, going along with a fairly mild air mass high up. Although sunny, Sunday will be fairly cold and windy high up. The high pattern is then expected to causing temperature inversion and springlike condition, more noticeable high up, from Monday until Wednesday. The pressure field remaining fairly high over the Alps, a probable polar air income by Thursday afternoon should not be triggering anything but a cloudy deterioration. Further outlook, although very uncertain, shows a possible snowy spell, light to moderate, between Saturday evening and Monday evening.
SATURDAY EVENING DECEMBER 20 - AND OVERNIGHT
Clear and cold - strong wind high up
SKY CONDITION : clear or partly cloudy - possible low cloud, locally, by the end of the night.
PRECIPITATIONradarlive precipitation over the Alps : none.
WIND - ground level : variable light.
WIND - mid mountain : NNW light -> NNE light to moderate.
WIND - high mountain : NW -> NNW strong.
TEMPERATURE : low -3°C.
ISOTHERM 0°C : 1600 -> 2000 m.
ISOTHERM -10°C : 3900 -> 4200 m.
Light temperature inversion towards 1300 m. Milder due to northerly fœhn wind in the Upper Aosta Valley.
ROAD CONDITION  : From Le Fayet to Chamonix : no traffic issue. At 06:00, from Chamonix towards Switzerland via the Montets Pass : no traffic issue.
TOMORROW - SUNDAY DECEMBER 21
Sunny - getting milder with decreasing wind high up
SKY CONDITION : clear or partly cloudy - possible low cloud, locally, early in the morning. period of sunshine close to 90%.
PRECIPITATION : none.
WIND - ground level : variable light.
WIND - mid mountain : NNE light to moderate -> light.
WIND - high mountain : NNW strong -> NW modéerate.
TEMPERATURE : low -3°C - high +5°C.
ISOTHERM 0°C : 2000 -> 2700 m.
ISOTHERM -10°C : 4200 -> 4600 m.
Milder due to northerly fœhn wind in the Upper Aosta Valley.
SUNDAY TO MONDAY NIGHT - DECEMBER 21 TO 22
Clear and cold - pronounced temperature inversion
SKY CONDITION  : clear or partly cloudy.
PRECIPITATION : none.
WIND - aloft : NW moderate.
TEMPERATURE : low -4°C.
Clearly positive temperature towards mid-mountain level.
MONDAY DECEMBER 22
Sunny - mild high up - temperature inversion
SKY CONDITION : clear or partly cloudy - high cloud patches crossing over in the afternoon. Period of sunshine close to 90%.
PRECIPITATION : none.
WIND - aloft : NW -> WNW moderate - moderate to strong at times.
TEMPERATURE : low -4 °C - high +8°C.
How milder exactly is slightly uncertain.
TUESDAY DECEMBER 23
Sunny ‑ considerably milder than seasonal average ‑ temperature inversion
SKY CONDITION : clear. Period of sunshine close to 100%.
PRECIPITATION : none.
WIND - aloft : W -> WSW moderate.
TEMPERATURE : low -1°C - high +10°C.
Uncertain.
EXTENDED OUTLOOK UNTIL FRIDAY DECEMBER 26 2014

Wednesday : sunny ‑ the air mass is getting colder from the north. Thursday : cold front crossing over in a fairly high pressure field ‑ fair sunny spells in the morning ‑ snow shower risk in the afternoon ‑ increasing wind high up. Friday : fairly sunny - strong N wind high up. Outlook is very uncertain from Thursday.

Forecast reliability : fairly good until Monday ‑ poor thereafter.

ReportsAs a reminder, today in Chamonix, the sun rises at 08:11:42 and goes down at 16:50:51.
45.55 N 6.51 E - Altitude 1040 m
22 December 08:00
Temperature -4°C
Relative humidity 95%
Wind 0 km/h
Sea level pressure 1034 hpa - rising slowly
Pressure at 1042 m 911 mb
Precipitation last 6h 0.0 mm
Skies clear
Visibility 70000 m
Altitude 3845 m
22 December 08:00
Temperature -6°C
Wind NW 50 km/h
Altitude 2250 m
22 December 06:00
Snow depth 5 cm
Wind 10 km/h
Gusts 20 km/h
Temperature +3°C