View
233
Download
4
Category
Tags:
Preview:
Citation preview
Weather Services CHAPTER 7
Content
• Aviation Weather Reports/Forcasts• Reading Weather Reports/Forcasts• TAF, FA, METAR, FD, Pireps
• Surface Weather Charts• Weather Depiction charts• Windshear avoidance
WEDNESDAY QUIZ
• ASA CHAPTER 7 • EVERY QUESTION IS FAIR GAME.
• APPOXIMATELY 73 QUESTIONS• QUIZ WILL BE 14 OF THE ABOVE
QUESTIONS• STUDY!!!!!!!
Reading Assignment
• Jeppesen Chapter 7• Gleim chapter 8 *****• ASA CHAPTER 7• AIM section 7• AC 00-45G Aviation Weather Services• PHAK CHAPTER 12• FMH-1 Section 12
Aviation Weather Reports and Forecasts (215)
• Where can one obtain weather information?
• FSS 1-800-WXBRIEF, TWEB (transcribed weather broadcast on NDB/VOR), PATWAS (pilot’s automatic telephone weather answering service, 50nm), TIBS (Telephone information briefing service, routes on demand service
Aviation Weather Reports and Forecasts
• Already in flight HIWAS (hazardous inflight weather advisory service, over VOR’s Airmets/Sigmets)
• EFAS (enroute flight advisory service, or flight watch, 122.0 mHz)enroute weather PIREPS
• Radio, Television, Internet, ATIS, Tower, DUATS etc..
How to get a good briefing
• Call FSS 1-800 WX-Brief, 1800 992-7433• Identify yourself as a pilot• Tell them about your flight• Type of flight, type of briefing as well as VFR or
IFR, Aircraft number or your name, aircraft type, departure point, route of flight, destination, flight altitude(s), estimated time of departute, estimated time en route or estimated time of arrival
Types of weather briefings
• Standard briefing includes everything• Abbreviated briefing - used to supplement
information you already have• Outlook briefing - when the briefing is 6 hours or
more in advance of proposed departure
METAR• METAR= Meteorological Aviation Routine
weather report• In 1996 US converted to the ICAO and the World
Meterological Organization form of aviation weather reporting.
• Each country is allowed to make modifications to the code to use in that particular country
• In the U.S. visibility is in statute miles, runway visual range in feet, wind speed in knots, and altimeter setting in inches of mercury
METAR
• Elements of a METAR
• 1. Type of Report• 2. ICAO station
identifier• 3. Date and time of
report• 4. Modifier (as
required)
• 5. Wind• 6. Visibility• 7. RVR• 8. Weather• 9. Sky conditions• 10. Temp/DPT• 11. Altimeter• 12. Remarks
GLEIM SUPPLEMENT METAR
METAR
• METAR KMWH 201933Z COR 24015KT 3/4SM R28/2400FT +TSRA BKN008 OVC015CB 26/25 A2985 RMK TSB32RAB32
• METAR KEPH 091955Z COR 22015G25KT 3/4SM R28L/2600FT TSRA OVC010CB 18/16 A2992 RMK SLP045 T01820159
METAR
METAR (226 & 200AFD)
• METAR’s are issued normally 5-10minutes before the hour every hour
• Ceiling is defined as the lowest broken or overcast layer or vertical visibility into a surface based obstruction
• Indefinite ceiling VV006• Temperature below zero prefixed with
a M
METAR (226 & 200AFD)
• A01-Automated station with out precipitation discrimination
• A02- with precip discrimination• VC in vicinity of airport 5-10 SM• METAR’s are reports (a moment of
time) not a forecast• FMH-1 SECTION 12
TAF (255 & 200AFD)
• Used to be called a FT• Is a forecast of the expected
weather conditions at an airport during a specific period (24hrs to 30 hours)
• Issued four times a day for 24-30 hrs periods (00Z, 06Z, 12Z, 18Z)
GLEIM TAF SUPPLEMENT
TAF (255 & 200AFD)
• Example: • TAF AMD KMWH 062223Z 0622/0718
20006KT P6SM VCSH SCT007 BKN020 OVC050 TEMPO 0622/0701 5SM BR BKN007 OVC015 FM070400 23005KT P6SM SCT080 OVC150
TAF (255 & 200AFD)
• Example: • TAF AMD KYKM 061937Z 0620/0718
VRB04KT P6SM VCSH OVC025 TEMPO 0620/0624 -RA OVC018 FM070000 VRB04KT P6SM VCSH SCT025 OVC050 TEMPO 0700/0704 -RA OVC025 FM070400 VRB04KT 5SM BR VCSH OVC025 FM070800 VRB03KT 4SM BR VCSH OVC020 FM071700 VRB04KT 6SM -RA BR OVC030
FA AVIATION AREA FORECAST (269)
• FA is a forecast of general weather conditions over an area the size of several states.
• It is used to determine forecast en route weather and to interpolate conditions at airports that do not have TAF’s issued.
• FA’s are issued 3 times a day for 6 different areas in the U.S. (00Z, 08Z, 16Z)
FA REGIONS
FA AVIATION AREA FORECAST (269)
• FA is comprised of four sections:• 1 Communication and product header
section• 2. A precautionary statement section• 3. Synopsis section• 4. VFR Clouds/WX section
FA AVIATION AREA FORECAST (269)
• The area we are in is the SFO San Francisco area
• 1. Communication 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
• 2. Precautionary statements. Three statements are in all FA’s
FA AVIATION AREA FORECAST (269)
• See airmet sierra for IFR conds and mtn obscn.
• TSTMS IMPLY PSPL SVR OR GTR TURBC SVR ICG LLWS AND IFR CONDS.
• NON MSL HGTS ARE NENOTED BY AGL OR CIG.
FA AVIATION AREA FORECAST (269)
• Synopsis - brief summary of the location and movement of fronts, pressure systems, and circulation patterns for an 18-hr. period
• VFR Clouds and Weather - contains a 12 hr. specific forecast, followed by a 6 -hr outlook giving a total forecast of 18hr
• (pg 271 overhead or DUAT example)
In-Flight WX advisories (278)
• Are forecasts that advise en route aircraft of the development of potentially hazardous weather
• Three different kinds of in-flight wx advisories
• 1. Convective SIGMET (WST)• 2. SIGMET (WS)• 3. AIRMET (WA)
In-Flight WX advisories (278)• All heights are MSL unless stated CIG• Convective SIGMET (WST) - Are issued for any
of the following• A severe thunderstorm due to 1. Surface winds
greater than or equal to 50kt, 2. Hail at the surface greater than or equal to 3/4 in. in diameter, 3. Tornadoes, 4. Embedded thunderstorms, 5. Line of thunderstorms, or 6. TS greater or = to VIP intensity level 4 affecting 40% or more of an area 3000 square miles.
In-Flight WX advisories (278)• Convective SIGMET (WST) - implies severe or
greater turbulence, severe icing, and low-level wind shear
• Issued for eastern (E), central (C), and western (W) United States.
• Bulletins are issued hourly at H+55• Each new bulletin is identified with a number• The text of the bulletin’s forecast is valid for up
to 2 hours. (Pg 281)
In-Flight WX advisories (278)• SIGMET (WS)- advises of nonconvective
weather that is potentially hazardous to all aircraft
• 1. Severe icing, 2. Severe or extreme turbulence or clear air turbulence not associated with a TS
• 3. Dustorms, sandstorms, or volcanic ash lowering surface visibilities to below 3SM
• 4. Volcanic eruption• The maximum forecast period is 6 hrs.
In-Flight WX advisories (278)
• Identified by alphabetic designators which inlude November through Yankee but exlude Sierra and Tango
• First issuance of a SIGMET with be labeled UWS (urgent weather SIGMET)
In-Flight WX advisories (278)
• Example• UWS 051710• SIGMET PAPA 1 VALID UNTIL 052110• AR LA MS• FROM STL TO 30N MEI TO BTW TO MLU
TO STL OCNL SVR ICING 90 TO 130 EXPCE.• FRZLVL 80 E TO 120 W. CONDS CONTG
BYD 2100Z
In-Flight WX advisories (278)
• AIRMET (WA)- are advisories of significant weather phenomena but describe conditions at intensities lower than those which trigger SIGMETs.
• Are bulletins issued on a scheduled basis every 6 hrs. Issued for: moderate icing, Moderate turbulence, sustained surface winds of 30 kt. Or more, IFR clouds and visibilites affecting over 50% of the area at one time, extensive mountain obscurement
In-Flight WX advisories (278)
• AIRMET - have fixed alphanumeric designators of:
• ZULU for icing• TANGO for turbulence• SIERRA for IFR and mountain obscuration• Pg 284 example
WINDS ALOFT FORECAST FD(285)
• Forecasts are made twice a day based on 00Z and 12Z data for use during specific time intervals
• Can be both an observation or a forecast.• Valid for a specific time • Gives winds at 3000ft, 6000ft, 9000ft, 12,000ft,
18,000ft, 24,000ft, 30,000ft, 34,000ft etc.• example winds and temperature at 9,000ft are written
as• 2725+00 = winds 270 degrees true and 25 knots
temperature 0 degrees C
WINDS ALOFT FORECAST FD(285)
• No winds are forecast within 1500ft of station elevation, also no temperature are forecast for the 3,000ft level or for any level within 2,500 ft of station elevation. Above 24000 no negative C
• If wind speed is over 100 knots (or from 100-199knots) the wind speed will have 50 added to the direction
• Example wind 230 degrees T at 150 knots =7350• Wind less than 5 kt codedas 9900 light and
variable (Show duat example)
FD GLEIM
PIREPS UA(245)• PIREPS (UA) - observations from pilots in the
cockpit. Provide the only means of directly observing cloud tops, icing, and turbulence.
• Trasmitted in a prescribed format• /OV = LOCATION, /TM = TIME, /FL =
ALTITUDE/FLIGHT LEVEL, /TP = AIRCRAFT TYPE, /SK = SKY COVER, /WX = FLIGHT VISIBILITY AND WEATHER, /TA = TEMPERATURE, /WV = WIND, /TB = TURBULENCE, /IC = ICING, /RM = REMARK
PIREP
PIREPS UA(245)
• The letter “UUA” identify an urgent PIREP• Example• UA/OV MWH/TM 1600/FL100/TP
B19/SK024 BKN 032/042 BKN-OVC/WX FV02 R H/ TA -12/WV 27020/TB LGT/IC LGT-MDT RIME 055-080/RM MDT RAIN
GLEIM UA FIGURE
Surface Analysis Chart (296)• Transmitted every 3 hours• Valid with the time of the plotted observations• Shows pressure systems (L & H)isobars in
4mb/hpa intervals, Fronts, wind speed, sky cover, cloud type, sea level pressure, temperature, present weather, dew point, 6 hour precipitation, pressure tendency, pressure change in last 3 hours, squall lines, troughs and ridges
Surface Analysis Chart (297)
• Picture of chart on 297 or duat/adds example• http://www.duat.com/
• http://www.rap.ucar.edu/weather/progs/prog00hr.gif
• http://aviationweather.gov/std_brief/
SURFACE ANALYSIS CHART
STATION MODEL AND SYMBOLS
Weather Depiction Chart (305)
• Is computer prepared from METARs.• Gives a broad overview of the observed flying category
conditions at the valid time of the chart• First one is issued at 1zulu and is then transmitted at 3
hour intervals, and is valid at the time of the plotted data
• Gives total sky cover, cloud height or ceiling, weather and obstructions to vision, visibility, analysis (if IFR, MVFR, or VFR)
• Good chart for initially sizing up the general weather picture
WEATHER DEPICTION GLEIM
Weather Depiction Chart (305)
• Show chart of Page 307• Or Duat example
• http://www.duat.com/• http://aviationweather.gov/std_brief/
RADAR SUMMARY CHART
PHAK RADAR SUMMARY
Low level significant weather prog chart (317)
• Is a four-panel chart• The two lower panels are 12 and 24 hr.
surface prognostic charts• The two upper panels are 12 and 24 hours
prognostic charts of significant weather from the sureface to 400 mb/hPa (24,000ft MSL)
• The charts show conditions as they are forecast to be at the valid time fo the chart
PROG CHARTS
GLEIM SIGNIFICANT PROG CHART
Low level significant weather prog chart (317)
• This chart is issued 4 times daily with the 12 and 24 hour forecasts based on the 0000Z, 0600Z, 1200Z, 1800Z synoptic data
• The two surface prog panels use standard symbols for fronts, significant troughs, and pressure centers. Also outlines areas of forecast precipitation and/or thunderstorms a. solid lines continuous or intermittent (stable air) precipitation. B. Dash-dot lines show showers and TS (unstable air precip)
Low level significant weather prog chart (317)
• Symbols indicate the type of precipitation • The upper panels depict IFR, MVFR,
turbulence, and freezing levels. There is a legend in the center of the chart which explains the methods of depiction.
Low level significant weather prog chart (317)
• show chart on page 318• http://aviationweather.gov/std_brief/
Wind Shear (42)
• Wind shear - generates eddies between two wind currents of differing velocities.
• A. The difference may be in wind speed, wind direction, or in both
• May be associated with either a wind shift or a wind speed gradient at any level in the atmosphere
Wind Shear (42)
• Four conditions are of special interest.• 1. Wind shear with a low-level temperature
inversion• 2. Wind shear in a frontal zone,• 3. Clear air turbulence at high levels
associated with a jet sstream or strong circulation
• 4. Micro burst with a thunderstorm
Wind Shear (42)• Temperature inversion - climbing or
descending through the inversion can cause airspeed to slow or increase, this relative wind fluctuations can cause the aircraft to reach its critical angle of attack and stall. (101) Especially if climbing into a strong tailwind above.
• If landing approach is into the wind above the inversion, when the headwind is lost descending through the inversion may induce a stall.
Wind Shear (42)• Good rule of thumb when ever gusty winds
are encountered or wind shear suspected at have the gust factor or half the difference in wind speed to your climb or approach speed.
• This gives a margin or safety if and when your enter turbulence or cross wind shear.
• Winds 10G30 add 10 knots to your approach speed.
Private PTS
• You need to know– METAR, TAF AND FA– Surface analysis chart– Radar summary chart– Winds and temperature aloft chart– Significant weather prognostic chart– Convective outlook chart.– AWOS, ASOS, and ATIS reports
USEFUL LINKS
• www.duat.com• www.duats.com• http://aviationweather.gov/• http://adds.aviationweather.gov/• http://aviationweather.gov/std_brief/• http://www.ofcm.gov/fmh-1/fmh1.htm
• http://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/74588
Recommended