CHAMONIX VALLEY AND MONT-BLANC AREA WEATHER FORECAST


Sōma Senshi
Particle
In the winter sun
I d'like to leave
ISSUED AT 08:35 FRIDAY NOVEMBER 17
VALID FROM : FRIDAY NOVEMBER 17 ‑‑ UNTIL : WEDNESDAY NOVEMBER 22 2017

GENERAL SYNOPSIS
High, 1029 hpa Southern Ireland, drifting over Brittany while weakening slightly by Saturday noon. It is linked to an altitude high cell made of subtropical air, which seems intended to moving away westward. • Deep low 972 hpa, Norwegian Sea, moving towards Southern Scandinavia by the same time. • Northwesterly stream is due to increasing between both areas of opposite action. • First cold front slowly crossing over the Alps today, without activity in a fairly high pressure field. It causes nothing else than high cloud passings over our Region, yet in a cooling down atmosphere, especially in the median altitude range. • Then, altitude stream, veering somewhat north‑northwest, is expected to propelling polar air southward along the eastern flank of the high pressure area, shaping a second cold front, hence moderately active, and to triggering some snowfall in the valley. • This outlook’s uncertainty mainly depends on the east‑west positioning of the unsettled cold air income.
TODAY - FRIDAY NOVEMBER 17
Fairly sunny ‑ cold in the morning ‑ milder in the afternoon
SKY CONDITION : coming and going low fog patch down in the valley, dispelling later ‑ else, partly cloudy to cloudy in the morning due to high cloud crossing over from the northwest ‑ skies probably clearing over the afternoon hours. Period of sunshine close to 80%.
PRECIPITATION : none.
WIND - ground level : SW ‑> NE light ‑> calm.
WIND - mid mountain : NE light.
WIND - high mountain : NNW light to moderate ‑> NW moderate.
TEMPERATURE : low ‑4°C - high +6°C - temperature inversion toward 1200 m early in the morning.
ISOTHERM 0°C : 2400 ‑> 2500 ‑> 2400 m.
ISOTHERM -10°C : 4100 ‑> 4200 ‑> 4000 m.
ROAD CONDITION  : @ 16:00, dry roadways on the whole. Black ice risk in foggy areas.morelive precipitation radar over the Alps
OVERNIGHT
Skies expected to clearing totally ‑ very cold in the valley
SKY CONDITION : still some high cloud passings at first, then skies will clear entirely.
PRECIPITATION : none.
WIND - aloft : NW ‑> NNW moderate.
TEMPERATURE : low ‑8°C.
SATURDAY NOVEMBER 18
Sunny ‑ very cold in the morning ‑ somewhat milder afternoon in the valley
SKY CONDITION : clear or partly cloudy ‑ thin high cloud crossing over in the afternoon. Period of sunshine close to 95%.
PRECIPITATION : none.
WIND - aloft : NNW moderate ‑> moderate to strong.
TEMPERATURE : low ‑8 °C - high +4°C.
SUNDAY NOVEMBER 19
Mostly cloudy ‑ snow showers likely ‑ probable gale high up
SKY CONDITION : mostly cloudy to overcast. Period of sunshine close to 20%.
PRECIPITATION : light snow shower likely, mostly in the morning.
WIND - aloft : NNW strong ‑ gale at times.
TEMPERATURE : slightly rising lows ‑ dropping highs.
EXTENDED OUTLOOK UNTIL WEDNESDAY NOVEMBER 22 2017

Monday : mostly cloudy ‑ fleeting sunny spells ‑ fairly strong northwest high up. Tuesday : mainly cloudy ‑ wintry shower likely. Wednesday : improving temporarily ‑ fairly sunny ‑ getting milder. Very uncertain for the three days.

Forecast reliability : fairly good today ‑ poor thereafter.

ReportsAs a reminder, today in Chamonix, the sun rises at 07:36:23 and goes down at 16:58:49.
45.55 N 6.51 E - Altitude 1040 m
November 17 07:00
Temperature -4°C
Relative humidity 97%
Wind 0 km/h
Sea level pressure 1020 hpa - rising slowly
Pressure at 1042 m 902 mb
Precipitation last 6h 0.0 mm
Skies clear - fog patches - sw down in the valley
Visibility 120000 m
Altitude 3845 m
November 17 07:00
Temperature -8°C
Wind N 25 km/h
Altitude 2250 m
November 17 06:00
Snow depth 10 cm
Wind 10 km/h
Gusts 20 km/h
Temperature +2°C