Figure 3-7. WA Example

CHAPTER THREE

METEOROLOGY FLIGHT PLANNING

WAUS1 KDFW 210745

DFWS WA 210745

AIRMET SIERRA FOR IFR AND MTN OBSCN VALID UNTIL 211400

AIRMET IFR...TN KY

FROM 30E TRI TO 20S CHA TO 40SW ABY TO MOB TO IGB TO MEM TO DYR TO 30E TRI

OCNL CIG BLW010/VIS BLW 3SM -RA/BR. CONDS SPRDG EWD AND CONTG BYD 14Z AND IMPVG

EXC ERN TN BY 20Z.

AIRMET MTN OBSCN...TN KY

FROM HNN TO 30E TRI TO 30E CHA TO CHA TO HNN

MTNS OCNL OBSCD IN CLDS/PCPN/FG. CONDS CONTG BYD 14A THRU 20Z.

DFWT WA 210745

AIRMET TANGO FOR TURB VALID UNTIL 211400

AIRMET TURB...AR OK TX TN MS LA AND CSTL WTRS

FROM 40S ICT TO ARG TO 20S BWG TO 80S LCH TO LRD TO 40S ICT

LGT OCNL MDT TURB FL140-FL350 ASSOCD WTH STG WNDSHR. CONDS CONTG BYD 14Z IMPVG

BY 20Z.

ELSW...NO SGFNT TURB EXC VC CNVTV ACT

DFWZ WA 210745

AIRMET ZULU FOR ICE AND FRZLVL VALID UNTIL 211400

AIRMET ICE...TN MS OK

OCNL LGT ISOLD MDT RIME ICGICIP FRZLVL TO ARND 120 MS AL AND TN. CONDS CONTG

BYD 14Z IMPVG BY 20Z.

Figure 3-7 WA Example

AIRMET bulletins, each containing one or more AIRMET messages, are issued on a scheduled

basis every six hours beginning at 0145 UTC, and are effective for six hours, beginning at 0200

UTC. Unlike FAs, scheduled AIRMET bulletin issuances occur at the same UTC time, regardless

of their area designator (Figure 3-7). Unscheduled amendments and corrections are issued as

necessary, due to changing weather conditions or issuance/cancellation of a SIGMET.

There are three types of AIRMET messages that may be issued within a WA. An AIRMET is

issued when one or more of the following listed conditions occurs (or is expected to occur) and

affects an area of at least 3000 square miles:

AIRMET Sierra For widespread IFR conditions (ceilings less than 1000 feet and/or visibility

less than three miles) affecting over 50% of the area or for extensive mountain obscuration.

AIRMET Tango For moderate turbulence or for sustained surface winds of 30 knots or more.

AIRMET Zulu For moderate icing or freezing level data.

3-14

SEVERE WEATHER WATCHES, MILITARY ADVISORIES, AND PIREPS