SL Helicopter Flying Handbook/Weather

SECTION 12. Weather

1 Introduction

Weather is an important factor that affects many aspects of a flight. Preflight preparations should always include a review of current and expected weather conditions along the route of flight.

3 Weather Services

3.2 METARS

A METAR is an observation of current surface weather reported in a standard format. This discussion of METAR covers elements used in Second Life. METARs are issued on a regularly scheduled basis.

A METAR report contains the following information in sequential order:

Example: SLWS 151605Z AUTO 15012KT 10SM -RA OVC030 25/12 A3009 RMK AO2

1. Station identifier— a four-letter code. In Second Life, airports have the prefix code "SL" while "HB" is the prefix for harbors. For example, White Star Airfield has the identifier "SLWS" with "SL" Being the prefix code and "WS" being the airport identifier.Station identifiers can be found on the Shergood Radar map.
2. Date and time of report —depicted in a six-digit group (151605Z). The first two digits are the date, given as the day of the current month. In the axample, its the 15th. The last four digits are the time of the METAR, which is always given in coordinated universal time (UTC). A “Z” is appended to the end of the time to denote the time is given in Zulu time (UTC) as opposed to local time. Second life time is UTC minus 7 hours from approximately Mid March to Early November, and UTC minus 8 hours the remainder of the year. In the example the time of observation is 16:05 which corresponded to 09:05 in second life, as the offset was minus 7 hours when the METAR was issued.
3. Modifier—denotes that the METAR came from an automated source. If the notation “AUTO” is listed in the METAR the report came from an automated source. All METARS in Second life come from automated weather stations.
4. Wind—reported with five digits (15012KT) The first three digits indicate the direction the true wind is blowing FROM. The last two digits will indicate the wind speed in Knots. In the example, the wind is blowing from 150, at a speed of 12 knots.
5. Visibility—the prevailing visibility (10SM) is reported in statute miles as denoted by the letters “SM”, up to 10 miles, visibility greater than 10 miles will be reported as 10. One statute mile is equal to 5,280 feet or approximately 1.6 kilometers.
6. Weather—can be broken down into two different categories: qualifiers and weather phenomenon (-RA). First, the qualifiers of intensity, proximity, and the descriptor of the weather are given. The intensity may be light (–), moderate ( ), or heavy (+). Weather phenomenon can be either rain (RA) or snow (SN). In the example, light rain is reported.
7. Sky condition—always reported in the sequence of amount and height. (OVC030) The heights of the cloud bases are reported with a three-digit number in tens of feet AGL. Contractions are used to describe the amount of cloud coverage and obscuring phenomena. The amount of sky coverage is reported in eighths of the sky obscured. Coverage can be reported as Clear (CLR)- less than 1/8 coverage, Few (FEW) Clear to 2/8 coverage,Scattered (SCT) - 3/8 to 4/8 coverage, Broken (BKN) - 5/8 to 6/8 coverage, and Overcast (OVC) - 7/8 to full coverage. In the example, the sky is reported as overcast, with the base of the clouds at 300 feet AGL.