时间：2011-04-18 00:50来源：蓝天飞行翻译 作者：航空 点击：次
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EXAMPLE. Example of a SIGMET: BOSR WS 050600 SIGMET ROMEO 2 VALID UNTIL 051000 ME NH VT FROM CAR TO YSJ TO CON TO MPV TO CAR MOD TO OCNL SEV TURB BLW 080 EXP DUE TO STG NWLY FLOW. CONDS CONTG BYD 1000Z. d. Convective SIGMET (WST)1. Convective SIGMETs are issued in the conterminous U.S. for any of the following: (a)Severe thunderstorm due to: (1)Surface winds greater than or equal to 50 knots. (2)Hail at the surface greater than or equal to 3/4 inches in diameter. (3) Tornadoes. (b)Embedded thunderstorms. (c)A line of thunderstorms. (d)Thunderstorms producing precipitation greater than or equal to heavy precipitation affecting 40 percent or more of an area at least 3,000 square miles. 2.Any convective SIGMET implies severe or greater turbulence, severe icing, and low.level wind shear. A convective SIGMET may be issued for any convective situation that the forecaster feels is hazardous to all categories of aircraft. 3.Convective SIGMET bulletins are issued for the western (W), central (C), and eastern (E) United States. (Convective SIGMETs are not issued for Alaska or Hawaii.) The areas are separated at 87 and 107 degrees west longitude with sufficient overlap to cover most cases when the phenomenon crosses the boundaries. Bulletins are issued hourly at H+55. Special bulletins are issued at any time as required and updated at H+55. If no criteria meeting convective SIGMET requirements are observed or forecasted, the message “CONVECTIVE SIGMET... NONE” will be issued for each area at H+55. Individual convective SIGMETs for each area (W, C, E) are numbered sequentially from number one each day, beginning at 00Z. A convective SIGMET for a continuing phenomenon will be reissued every hour at H+55 with a new number. The text of the bulletin consists of either an observation and a forecast or just a forecast. The forecast is valid for up to 2 hours. Meteorology 7.1.15 EXAMPLE. Example of a Convective SIGMET: MKCC WST 251655 CONVECTIVE SIGMET 54C VALID UNTIL 1855Z WI IL FROM 30E MSN.40ESE DBQ DMSHG LINE TS 15 NM WIDE MOV FROM 30025KT. TOPS TO FL450. WIND GUSTS TO 50 KT POSS. CONVECTIVE SIGMET 55C VALID UNTIL 1855Z WI IA FROM 30NNW MSN.30SSE MCW DVLPG LINE TS 10 NM WIDE MOV FROM 30015KT. TOPS TO FL300. CONVECTIVE SIGMET 56C VALID UNTIL 1855Z MT ND SD MN IA MI LINE TS 15 NM WIDE MOV FROM 27020KT. TOPS TO FL380. OUTLOOK VALID 151855.252255 FROM 60NW ISN .INL.TVC.SBN.BRL .FSD. BIL.60NW ISN IR STLT IMGRY SHOWS CNVTV CLD TOP TEMPS OVER SRN WI HAVE BEEN WARMING STEADILY INDCG A WKNG TREND. THIS ALSO REFLECTED BY LTST RADAR AND LTNG DATA. WKNG TREND OF PRESENT LN MAY CONT...HWVR NEW DVLPMT IS PSBL ALG OUTFLOW BDRY AND/OR OVR NE IA/SW WI BHD CURRENT ACT. A SCND TS IS CONTG TO MOV EWD THRU ERN MT WITH NEW DVLPMT OCRG OVR CNTRL ND. MT ACT IS MOVG TWD MORE FVRBL AMS OVR THE WRN DAKS WHERE DWPTS ARE IN THE UPR 60S WITH LIFTED INDEX VALUES TO MS 6. TS EXPD TO INCR IN COVERAGE AND INTSTY DURG AFTN HRS. WST ISSUANCES EXPD TO BE RQRD THRUT AFTN HRS WITH INCRG PTNTL FOR STGR CELLS TO CONTAIN LRG HAIL AND PSBLY DMGG SFC WNDS. e. International SIGMET 1.Some NWS offices have been designated by the ICAO as Meteorological Watch Offices (MWOs). These offices are responsible for issuing International SIGMETs for designated areas that include Alaska, Hawaii, portions of the Atlantic and Pacific Oceans, and the Gulf of Mexico. 2.The offices which issue International SIGMETs are: (a)The AWC in Kansas City, Missouri. (b)The AAWU in Anchorage, Alaska. (c)The WFO in Honolulu, Hawaii. (d)The WFO on Guam Island in the Pacific Ocean. 3. These SIGMETs are considered “wide-spread” because they must be either affecting or be forecasted to affect an area of at least 3,000 square miles at any one time. The International SIGMET is issued for 12 hours for volcanic ash events, 6 hours for hurricanes and tropical storms, and 4 hours for all other events. Like the domestic SIGMETs, Interna-tional SIGMETs are also identified by an alphabetic designator from Alpha through Mike and are numbered sequentially until that weather phenome-non ends. The criteria for an International SIGMET are: (a)Thunderstorms occurring in lines, em-bedded in clouds, or in large areas producing tornadoes or large hail. (b)Tropical cyclones. (c)Severe icing. (d)Severe or extreme turbulence. (e)Dust storms and sandstorms lowering visibilities to less than 3 miles. (f)Volcanic ash. EXAMPLE. Example of an International SIGMET: WSNT06 KKCI 022014 SIGA0F KZMA KZNY TJZS SIGMET FOXTROT 3 VALID 022015/030015 KKCI. MIAMI OCEANIC FIR NEW YORK OCEANIC FIR SAN JUAN FIR FRQ TS WI AREA BOUNDED BY 2711N6807W 2156N6654W 2220N7040W 2602N7208W 2711N6807W. TOPS TO FL470. MOV NE 15KT. WKN. BASED ON SAT AND LTG OBS. MOSHER f. AIRMET (WA)1. AIRMETs (WAs) are advisories of signifi-cant weather phenomena but describe conditions at intensities lower than those which require the issuance of SIGMETs. AIRMETs are intended for dissemination to all pilots in the preflight and en route phase of flight to enhance safety. AIRMET Bulletins are issued on a scheduled basis every 6 hours beginning at 0145 UTC during Central Daylight Time and at 0245 UTC during Central Standard Time. Unscheduled updates and corrections are issued as necessary. Each AIRMET Bulletin contains any current AIRMETs in effect and an outlook for 7.1.16 Meteorology conditions expected after the AIRMET valid period. AIRMETs contain details about IFR, extensive mountain obscuration, turbulence, strong surface winds, icing, and freezing levels. 2. There are three AIRMETs: Sierra, Tango, and Zulu. After the first issuance each day, scheduled or unscheduled bulletins are numbered sequentially for easier identification. (a)AIRMET Sierra describes IFR conditions and/or extensive mountain obscurations. (b) |
