December 1999 4-11 TAF KCRP 111730Z 111818 19007KT P6SM SCT030 TEMPO 1820 BKN040 FM2000 16011KT P6SM VCTS FEW030CB SCT250 FM0200 14006KT P6SM FEW025 SCT250 FM0800 VRB03KT 5SM BR SCT012 TEMPO 1012 1/2SM FG BKN001 FM1500 17007KT P6SM SCT025= TAF Aviation terminal forecast KCRP Corpus Christi, Texas 111730Z prepared on the 11th at 1730Z 111818 valid period from the 11th at 1800Z until the 12th at 1800Z 19007KT wind 190 at 7 knots P6SM visibility greater than 6 statute miles SCT030 3,000 scattered TEMPO 1820 temporary conditions between 1800Z and 2000Z BKN040 ceiling 4,000 broken FM2000 from 2000Z 16011KT wind 160 at 11 knots P6SM visibility greater than 6 statute miles VCTS thunderstorms in the vicinity FEW030CB SCT250 3,000 few with cumulonimbus, 25,000 scattered FM0200 from 0200Z 14006KT wind 140 at 6 knots P6SM visibility greater than 6 statute miles FEW025 SCT250 2,500 few, 25,000 scattered FM0800 from 0800Z VRB03KT wind variable at 3 knots 5SM visibility 5 statute miles BR mist SCT012 1,200 scattered TEMPO 1012 temporary conditions between 1000Z and 1200Z 1/2SM visibility ½ statute mile FG fog BKN001 ceiling 100 broken FM1500 from 1500Z 17007KT wind 170 at 7 knots P6SM visibility greater than 6 statute miles SCT025= 2,500 scattered; the equal sign signifies the end of the TAF
December 1999 4-12 TAF KACK 112340Z 120024 29008KT P6SM SKC BECMG 1618 22015KT= TAF Aviation terminal forecast KACK Nantucket, Massachusetts 112340Z prepared on the 11th at 2340Z 120024 valid period from the 12th at 0000Z until the 13th at 0000Z 29008KT wind 290 at 8 knots P6SM visibility greater than 6 statute miles SKC sky clear BECMG 1618 becoming between 1600Z and 1800Z 22015KT= wind 220 at 15 knots; the equal sign signifies the end of the TAF TAF KMWH 200535Z 200606 NIL= TAF Aviation terminal forecast KMWH Moses Lake, Washington 200535Z prepared on the 20th at 0535Z 200606 valid period from the 20th at 0600Z to the 21st at 0600Z NIL= no TAF; the equal sign signifies the end of the TAF
December 1999
•КСТВ KFCA •KHVR
•KGGW
•KGTF KMSO •KHLN KLWT KSDY O •KISN •KMOT KGFK
MOLE MT ND KBZNO •KLVM •KBIL •KMLS •KDIK •KBIS KuMS KFAR ID OR
• KBNO KCOD • KSHRO KABR•
•KLMT •KSUN KIDA® • KGCC SD KATY•
• KWAL
• КРІН •КЛАС •KRAP KPIR • •KHON
• KRIW KLND • •KCPR KFSD • WY •KCDR
•KLOL DREKO
•KUKI *KENY KOGD KRKS • • KRWL •KBFF KSFOR ROAK OKSCK NV KELY• KPVU * KVEL• KHDN• KLAR KCYS. KLBF • NE KOFK • KGRI• KLNK•
•КМСЕКВІН» • КТРН UT • KGJT KEGE• KBJC KDEr ARKEYS •KFAT CA KCDC• •KBCE KMTJ• KASE • • KGUC • KCOS •KGLD KASL • •KSLN KMHK KTOF OKFOE
•KVBG •KPRB •KSMX OKSBA KPMD KWIFSKEDW •KBFL •KDAG KDRA KLAS KLVS KGON• OKFMN KGCK • •KDDG KS KICT• KCNU• •KHUT T•KGAG •KEND KTUL• • KPNC KEED KFLGE •KINW • KGUP KSAF •KLVS •KDHT →KTRM KPRCO AZ KABQ• KTCC• •KAMA KOKC OK •KMLC
•KHBR
•KSAN КРНХ• NM KCVS - KCDS•-
•KROW •KLBB KTCS•
•KHMN KTUS• KDUG •KDMN •KMAF KABI KFTW KOENKOAL KTYA• KGGG
• KSJT KACT • KLFK• TX TAF LEGEND KDAT KAUS •KCLL KAOU MAKELS
• Forecast Location * Suspended Forecast Location Figure 4-1. TAF Locations - Western Contiguous United States.
4-13
December 1999 ME
• KBJI •KHIB KBGRE KBAD • KOLH• *KMSS IKBVT KAUG• İKAXN=
VITIEKLER KGFLO KAWF • KAST• KISE WI KOSH• KMBSİ KIAG #KROC' ASYA KUC NY KALB KBAE KORH KBOS KMKG EKSux KMCW• IA KALO• KDBQO KÇID• KMSN• KAKE KAFDO KORD KDPAL <MOW ¡KAZO KUAN KOTW! EKSBN • KGARLAN KFN • KDET• "ŘTÖL KCAKEYNG KBVI EKCLE ATKERI •KFKL PA KIPT ZIHW • KOW KUNY KAVP• KABE•" KISP •СТ' KDSM• KMLI - KFDY• •KMFD KOTM KBAL •КРІА KFYYA KCNH RZZY KACY
•KLAF КИСІ KUN KSPY KDEC Skhur IN •KIND KDAY MY, KEKNI ТаКМКС •KCOU KS KCHO# KRICES MO SEWI DF •KLEX KROA VA KLOZI
•KJLN #KSGF KCGI• КРАН KBWG KINT• KADU KENA - KTY KHKY• NC KJBA• •KMKL TN KGLT KFAY OKFSM AR •KLIT КМЕМ •KMSL HEY I KIL N KHOT• •KPBF ‹ KTUPI AL SC MS
•KTXK KGLH •KGWO •KMON
•KELD OKTCL • KCSG KSHV •KMLU KMEI GA KIAN
LA KDHNO KVLD#
•КАЕХ- КИСВ• •КРІВ КРОЕ / •KLCH KLPT KGNY KDABO
OKSRO FL
TAF LEGEND
• Forecast Location KEYWO Figure 4-2. TAF Locations - Eastern Contiguous United States.
4-14
December 1999 GUAM
• PGSA Saipan, Mariana Is.
• PGUM (Agana, Guam, Mariana Is.)
• PTYA (Yap, Micronesia)
• PTRO (Koror, Palau Is.) (Chuuk, Micronesia) PIKK•. • PTPN •(Pohnpei, Micronesia)
PUERTO RICO AND THE VIRGIN ISLANDS
TUBQ TJSJ (Aquadilla) (San Juan) (Mayaguez) TJMZ • TIST (St. Thomas) • TNCM TJPS (Phillipsburg, St. Maarten) (Ponce) • TISX (Christiansted, St. Croix) (Basseterre, St. Kitts) Figure 4-3. TAF Locations - Guam and Puerto Rico.
4-15
December 1999 PASC PAOT •РАВТ
• PAOM
• PAGA •PATA SPAFA → PAUN ПРАВІ
•PAMC PAOR T
• PAGK I PAEN
• PASN PAYA → PAGY
• PAJN PADQ
PASI TEPAPG CYPAWG = a PAPADU
ALASKA LOCATIONS SPHLI
PHMK PHOG TAFs also prepared for the following by Honolulu (not plotted on map) PJON - Johnston Island 16.44N 169.31W PTSA - Kosrae. Micronesia 9.30N 143.00E PKWA - Kwajalein, Marshall Is. 167.431 PKMJ - Majuro, Marshall Is. 7.05N 171.23E NSTU - Pago Pago. Amer. Samoa 14.20N 170.43W PHKO PWAK - Wake Island 19.17N 166.392
HAWAII LOCATIONS Figure 4-4. TAF Locations - Alaska and Hawaii.
4-16
December 1999 4-17
AVIATION AREA FORECAST (FA) An Aviation Area Forecast (FA) is a forecast of visual meteorological conditions (VMC), clouds, and general weather conditions over an area the size of several states. To understand the complete weather picture, the FA must be used in conjunction with the inflight aviation weather advisories. Together, they are used to determine forecast en route weather and to interpolate conditions at airports for which no TAFs are issued. Figure 4-5 on page 4-21 maps the FA areas. The FAs are issued 3 times a day by the Aviation Weather Center (AWC) in Kansas City, Missouri, for each of the 6 areas in the contiguous 48 states. The weather forecast office (WFO) in Honolulu issues FAs for Hawaii as shown in Figure 4-6 on page 4-22. Alaska FA information is on page 4-27. There are also two specialized FAs, one for the Gulf of Mexico and one for international airspace.
This is a partial example of an FA which will be used in this section:
DFWC FA 120945
SYNOPSIS AND VFR CLDS/WX SYNOPSIS VALID UNTIL 130400 CLDS/WX VALID UNTIL 122200...OTLK VALID 122200-130400 OK TX AR TN LA MS AL AND
CSTL WTRS .
SEE AIRMET SIERRA FOR IFR CONDS AND MTN OBSCN.
TS IMPLY SEV OR GTR TURB SEV ICE LLWS AND IFR CONDS.
NON MSL HGTS DENOTED BY AGL OR CIG.
.
SYNOPSIS...LOW PRES TROF 10Z OK/TX PNHDL AREA FCST MOV EWD INTO CNTRL-SWRN OK BY 04Z. WRMFNT 10Z CNTRL OK-SRN AR-NRN MS FCST LIFT NWD INTO NERN OK- NRN AR XTRM NRN MS BY 04Z.
.
S CNTRL AND SERN TX AGL SCT-BKN010. TOPS 030. VIS 3-5SM BR. 14-16Z BECMG AGL SCT030. 19Z AGL SCT050.
OTLK...VFR.
.
OK PNHDL AND NW...AGL SCT030 SCT-BKN100. TOPS FL200. 15Z AGL SCT040 SCT100. AFT 20Z SCT TSRA DVLPG..FEW POSS SEV. CB TOPS FL450. OTLK...VFR.
SWRN OK...CIG BKN020. TOPS 050. VIS 3-5SM BR. 14Z AGL SCT-BKN040. 18Z CIG BKN060.
TOPS FL180. 22Z SCT TSRA DVLPG..FEW POSS SEV. CB TOPS ABV FL450. OTLK...VFR.
NERN QTR...CIG BKN020 OVC050. VIS 3-5SM NMRS TSRA..FEW POSS SEV. CB TOPS ABV FL450. 15Z AGL SCT030 SCT-BKN100. TOPS FL250. 18Z AGL SCT040. OTLK...VFR.
SERN QTR...AGL SCT-BKN020. TOPS 050. 18Z AGL SCT040. OTLK...VFR.
.
CSTL WTRS LA MS AL WTRS...SCT025 SCT-BKN080. TOPS 150. ISOL -TSRA. CB TOPS FL350. OTLK...VFR.
TX WTRS...SCT CI. OCNL SCT030. OTLK...VFR. ....
December 1999 4-18 The FA is comprised of four sections: a communications and product header section, a precautionary statements section, and two weather sections - a synopsis section and a visual flight rules (VFR) clouds/weather section.
COMMUNICATIONS AND PRODUCT HEADER The communications and product header identifies the office for which the FA is issued, the date and time of issue, the product name, the valid times, and the states and/or areas covered by the FA. The following shows the communications and product header for the example FA shown on page 4-17:
DFWC FA 120945
SYNOPSIS AND VFR CLDS/WX SYNOPSIS VALID UNTIL 130400 CLDS/WX VALID UNTIL 122200...OTLK VALID 122200-130400 OK TX AR TN LA MS AL AND
CSTL WTRS In the first line, “DFW” indicates the area for which the FA is valid. The “C” indicates VFR clouds and weather while the FA indicates what type of forecast message it is. The “120945” indicates the date and time the FA was issued. The next line “SYNOPSIS AND VFR CLDS/WX” states what information is contained in this forecast message. “SYNOPSIS VALID UNTIL 130400” means the synopsis section of the FA is valid until the thirteenth at 0400Z. The “CLDS/WX VALID UNTIL 122200...OTLK VALID 122200-130400” statement indicates the forecast section is valid until the twelfth at 2200Z, while the outlook portion is valid from the twelfth at 2200Z until the thirteenth at 0400Z. “OK TX AR TN LA MS AL AND CSTL WTRS” describes the area for which this FA forecast is valid.
PRECAUTIONARY STATEMENTS Between the communications/product header and the body of the forecast are three precautionary statements. (See example FA on page 4-17.) The first statement in the example, “SEE AIRMET SIERRA FOR IFR CONDS AND MTN OBSCN,” is included to alert users that IFR conditions and/or mountain obscurations may be occurring or may be forecasted to occur in a portion of the FA area. The user shall always check the latest AIRMET Sierra for the FA area.
The second statement in the example, “TS IMPLY SEV OR GTR TURB SEV ICE LLWS AND IFR CONDS,” is included as a reminder of the hazards existing in all thunderstorms. Thus, these thunderstorm-associated hazards are not spelled out within the body of the FA.
The purpose of the third statement in the example, “NON MSL HGTS DENOTED BY AGL OR CIG,” is to alert the user that heights, for the most part, are mean sea level (MSL). All heights are in hundreds of feet. For example, “BKN030. TOPS 100. HYR TRRN OBSCD,” means bases of the broken clouds are 3,000 feet MSL with tops 10,000 feet MSL. Terrain above 3,000 feet MSL will be obscured. The tops of the clouds, turbulence, icing, and freezing level heights are always MSL.
Heights AGL are noted in either of two ways:
1. Ceilings by definition are above ground. Therefore, the contraction “CIG” indicates above ground.
For example, ‘CIG BKN-OVC015,” means that ceilings are expected to be broken to overcast sky cover with bases at 1,500 feet AGL.
2. The contraction “AGL” means above ground level. Therefore, “AGL SCT020” means scattered clouds with bases 2,000 feet AGL.
December 1999 4-19 Thus, if the contraction “AGL” or “CIG” is not denoted, height is automatically above MSL.
SYNOPSIS The synopsis is a brief summary of the location and movements of fronts, pressure systems, and other circulation features for an 18-hour period. References to low ceilings and/or visibilities, strong winds, or any other phenomena the forecaster considers useful may also be included. The following synopsis is taken from the example on page 4-17.
SYNOPSIS...LOW PRES TROF 10Z OK/TX PNHDL AREA FCST MOV EWD INTO CNTRL-SWRN OK BY 04Z. WRMFNT 10Z CNTRL OK-SRN AR-NRN MS FCST LIFT NWD INTO NERN OK- NRN AR XTRM NRN MS BY 04Z.
This paragraph states that a low pressure trough at 10Z was over the Oklahoma (OK)/Texas (TX) panhandle area. The area is forecasted to move eastward into central-southwestern OK by 04Z. At 10Z a warm front was located from central OK to southern Arkansas (AR) to northern Mississippi (MS). This warm front is forecasted to lift into northeastern OK, northern AR, to extreme northern MS by 04Z.
VFR CLOUDS AND WEATHER (VFR CLDS/WX) This section contains a 12-hour specific forecast, followed by a 6-hour categorical outlook giving a total forecast period of 18 hours, and it is usually several paragraphs in length. The breakdown may be by states or by well-known geographical areas. (See Figure 4-11.) The specific forecast section gives a general description of clouds and weather which cover an area greater than 3,000 square miles and are significant to VFR flight operations.
Surface visibility and obstructions to vision are included when the forecast visibility is 3 to 5 statute miles. Precipitation, thunderstorms, and sustained winds of 20 knots or more will always be included when forecasted. The conditional term OCNL (occasional) is used to describe clouds and visibilities that may affect VFR flights. It is used when there is a greater than 50% probability of a phenomenon occurring, but for less than ½ the forecast period. The areal coverage terms ISOL (isolated), WDLY SCT (widely scattered), SCT or AREAS (scattered), and NMRS or WDSPRD (numerous or widespread) are used to indicate the area coverage of thunderstorms or showers. The term ISOL may also be used to describe areas of ceilings or visibilities that are expected to affect areas less than 3,000 square miles.
Table 4-1 defines the areal coverage terms.
Table 4-1 Areal Coverage of Showers and Thunderstorms Terms Coverage Isolated (ISOL) Single cells (no percentage) Widely scattered (WDLY SCT ) Less than 25% of area affected Scattered or Areas (SCT or AREAS) 25 to 54% of area affected Numerous or Widespread (NMRS or WDSPRD) 55% or more of area affected
December 1999 4-20 Example from the FA on page 4-17:
CSTL WTRS LA MS AL WTRS...SCT025 SCT-BKN080. TOPS 150. ISOL -TSRA. CB TOPS FL350. OTLK...VFR TX WTRS...SCT CI. OCNL SCT030. OTLK...VFR. ....
This part of the VFR clouds/weather section is the forecast for the coastal waters of Louisiana (LA), Mississippi (MS), Alabama (AL), and Texas (TX). For the coastal waters of LA, MS, and AL, the base of the scattered layer is 2,500 feet MSL. The second layer is scattered to broken at 8,000 feet MSL with tops at 15,000 feet MSL. Also during this time, isolated (ISOL) thunderstorms with light rain showers are expected with the tops of the thunderstorms (CB) at flight level (FL) 350. FL is used only for altitudes 18,000 feet MSL and higher. The visibility is expected to be greater than 6 statute miles and winds less than 20 knots, both by omission. The weather conditions along the TX coastal waters are expected to be scattered cirrus with occasional (OCNL) scattered layers at 3,000 feet MSL.
A categorical outlook, identified by “OTLK,” is included for each area breakdown. A categorical outlook of instrument flight rules (IFR) and marginal VFR (MVFR) can be due to ceilings only (CIG), restriction to visibility only (TSRA, FG, etc.), or a combination of both. In the example, the coastal areas have outlooks of VFR conditions.
The statement, “OTLK…VFR BCMG MVFR CIG F AFT 09Z,” means the weather is expected to be VFR, becoming MVFR due to low ceiling, and visibilities restricted by fog after 0900Z. “WND” is included in the outlook if winds, sustained or gusty, are expected to be 20 knots or greater.
Hazardous weather (i.e., IFR, icing, and turbulence conditions) is not included in the FA but are included in the Inflight Aviation Weather Advisories (see page 4-23).
AMENDED AVIATION AREA FORECAST Amendments to the FA are issued as needed. An amended FA is identified by AMD that is located on the first line after the date and time. The entire FA is transmitted again with the word UPDT after the state to indicated what sections have been amended/updated. FAs are also amended and updated by inflight aviation weather advisories (AIRMETs, SIGMETs, and Convective SIGMETs). A corrected FA is identified by COR and a delayed FA is identified by RTD which are located in the first line after the time and date.
December 1999
BOS BOSTON AVIATION AREA FORECASTS CHI CHICAGO DALLAS/FT. WORTH Figure 4-5. FA Locations - Contiguous United States.
DFW
SLC SALT LAKE CITY ŠFO SAN FRANCISCO 4-21
December 1999 4-22 Figure 4-6. FA Locations - Hawaii.