Extra Forecast Information for SMHI Tables

Table info

LEVEL: The levels are presented in meters but actually based on air

pressure. The heights for different camps in the forecast will thus

vary. The pressure level is presented in the forecast as follows:

Height      Pressure (hPa)

BC 495

C1 457

C2 437

C3 415

C4 375

Summit1 346

Summit2 330

WIND: The first figure indicates wind speed in meters/second. The

second wind direction. 1 m/s = 3.6 km/hour

1 m/s = 2.2 miles/hour

1 m/s = 1.9 knots

By definition a Storm is above 17 m/s, Hurricane is above 32 m/s.

HUMIDITY: High humidity % indicates high risk of snow/rain. Snow fall

is also determined by other factors like air pressure and temperature.

High humidity doesn't necessarily bring snow fall, but the chances

certainly increase. To simplify: At a humidity level above 50 - 60 %

there is a chance of snow. At 80 % or higher it is a very high chance

of snow.

VARIATIONS IN TABLE: The table is made by a super computer. The

Synopsis by a meteorologist. The super computer will do it's

prediction at an exact time. Wind speeds for camp one can thus vary in

the table at 5 m/s and then suddenly 15m/s and then back to 5 again.

This is a variation in the computer model. ALWAYS judge the overall

pattern in the tables and combine with info from the synopsis made by

the mets.

TIME: All times are GMT.

SYNOPSIS: The synopsis is made daily by a team of meteorologists. The

final forecast is based on information from the table, satellite

images and other sources. The Synopsis is then sent to

AdventureWeather for a check. Often there are follow up discussions

before it is actually distributed to climbers around Himalaya.

Sometimes the synopsis might differ from the table. Friday was a good

example. The table shows 100% humidity for three days starting Monday.

However, the meteorologists believe there is a chance that the main

system actually moves South from Everest. He thus wrote "risk of wide

spread precipitation".