Weather Services. What is an Observation? Observations are raw weather data collected by some type...

Weather Services

What is an Observation?• Observations are raw weather data collected by some type of

sensor(s)• Two categories of observations• On site (e.g. surface or airborne) • Remote (e.g. weather radar, satellite, profiler, and lightning)

© 2015 Coast Flight Training. All Rights Reserved.

Types of Observations• Surface aviation weather observations• Upper air observations• Radar observations


Dissemination of Weather Products• Weather Briefings (Lockheed Martin Flight Service)• Direct User Access Terminal Service (DUATS)• Transcribed Information Briefing Service (TIBS)• Hazardous Inflight Weather Advisory Service (HIWAS)• Flight Service Stations


First Method• In advance of day of flight•Weather Channel• Newspaper• Local News• Radio


Non-Aviation Related•Weather Channel• USA Today• San Diego Tribune


Flight Service Station• Primary source for obtaining preflight briefings and inflight

weather information•Weather Briefings• Standard• Abbreviated – used to supplement already obtained information• Outlook – used when departure is 6 hours or more in the future• Inflight – enroute weather

• Available throughout the US on 122.2


Flight Service Station• Provide pilots with• Weather briefings• Enroute weather

• Receive and process IFR and VFR flight plans • Relay ATC clearances• Issue Notices to Airmen (NOTAMs). • Provide assistance to lost aircraft and aircraft in emergency situations• Conduct VFR search and rescue services


Flight Service – Lockheed Martin• Dial 1-800-WX-Brief• Ask for a Briefer• Select State departing from• Local Briefers


Direct Users Access Terminal (DUATS)• Provides weather briefings via computer• Allows flight plans to be filed via computer• Free for any certificated pilot• Sign-up for DUATS online with Student Pilot Certificate Number


Direct Users Access Terminal (DUATS)• Allows any pilot with a current medical certificate to access weather

information and file a flight plan via computer• Run by Computer Sciences Corporation (CSC)• The current vendors of DUATS services and the associated phone

numbers are listed in Chapter 7 of the Aeronautical Information Manual (AIM)• Acceptable means of filing a flight plan, though not as dependable as

calling a briefer


Transcribed Information Briefing Service • Service of Automated Flight Service Stations (AFSS)• Provides continuous telephone recordings of meteorological and

aeronautical information• TIBS provides area and route briefings, as well as airspace procedures

and special announcements, if applicable• It is designed to be a preliminary briefing tool and is not intended to

replace a standard briefing from a flight service specialist


Transcribed Information Briefing Service • Available 24 hours a day • Updated when conditions change• Can only be accessed by a touch-tone phone• The phone numbers for the TIBS service are listed in the Airport/Facility

Directory (A/FD)• Should also contain, but is not limited to

• Surface observations• TAFs• Winds and temperatures aloft forecasts


Hazardous Inflight Weather Advisory Service• HIWAS is a national program for broadcasting hazardous weather

information continuously over selected navaids• The broadcasts include advisories such as AIRMETs, SIGMETS, convective

SIGMETs, and urgent PIREPs• These broadcasts are only a summary of the information, and pilots should

contact a FSS/AFSS or an En Route Flight Advisory Service (EFAS) for detailed information

• The HIWAS broadcast area is defined as the area within 150 NM of HIWAS outlets


Transcribed Weather Broadcast• Continuous broadcasts of recorded NOTAM and weather information prepared

for a 50-nautical mile wide zone along a route and for selected terminal areas• TWEBs are broadcast over selected NDB and VOR facilities and generally contain

• Weather synopsis• In-flight advisories• Route and/or local vicinity forecasts • Winds aloft forecasts• Current weather reports • NOTAMs• Special notices


Other Sources• Commercial Vendors• Provide weather products on a subscription basis• Examples: WSI, DTN, Kavouras

• Internet• Aviation Weather Center (Not a proper source)


Weather Briefings• Prior to every flight pilots should gather all information vital to the

nature of the flight• Sources: FSS, AFSS, DUATS• Has specific formatting• Three types of briefings• Standard• Outlook• Abbreviated


Briefing Format• Adverse conditions• VFR not recommended• Synopsis• Current conditions• Enroute forecast• Destination forecast• Winds and temperatures aloft• NOTAMS• ATC delays• Other information


Standard Briefing• A standard briefing provides a complete weather picture and is the

most detailed of all briefings• This type of briefing should be obtained prior to the departure of any

flight and should be used during flight planning• A standard briefing provides information in the standard format, as

provided in the previous slide


Abbreviated Briefing• An abbreviated briefing is a shortened version of the standard briefing• It should be requested when a departure has been delayed or when

specific weather information is needed to update a previous standard briefing• When this is the case, the weather specialist needs to know the time

and source of the previous briefing so that pertinent weather information will not be omitted inadvertently


Outlook Briefing• An outlook briefing should be requested when a planned departure is 6 or

more hours away• It provides initial forecast information that is limited in scope due to the

timeframe of the planned flight• This type of briefing is a good source of flight planning information that can

influence decisions regarding route of flight, altitude, and ultimately the “go or no-go” decision• Should be followed up with another briefing closer to the estimated time of

departure


METARS• Hourly report from a station• Usually given between 48 minutes and 3 minutes after the hour• If weather changes within the hour, called a SPECI• Special Aviation Weather Report


Reading the METAR


Elements – Report Type• Report Type

• METAR• Observation made between H+45 till the hour• Report transmitted between H+50 till the hour

• SPECI – non-routine observation made when specified criteria are net

• ICAO Station Identifier• Date and Time

• Day of month observation was taken• Zulu time when the observation was taken

• Modifier• AUTO – Automated Observation, No Human Intervention• COR – Corrected report


Elements - Wind• Reported in knots (KT)• Calm Wind (00000KT)• Variable• VRB – wind varies in direction and is 6 knots or less

• Reference to TRUE North• Gust• 32012G25


Elements - Visibility• Visibility• Reported in Statute Miles (SM)• When visibility is less than 7SM restrictions to visibility will be shown in the

weather element• When tower or surface visibility is less than 4SM, the lesser will be reported

in the body of the report, the greater will be reported in the remarks

• Runway Visual Range• R19/1200FT


Elements - Precipitation• Qualifiers• Intensity

- Light Moderate (no symbol)+ Heavy• Proximity

• VC – Vicinity of Airport (5 to 10 SM)


Elements - Descriptors• MI – Shallow – Fog with vertical extent less than 6 feet• BC – Patches – Fog with little vertical extent that reduces horizontal visibility• DR – Low Drifting – Dust, Sand, or Snow raised by the wind less than 6 feet• BL – Blowing – Dust, Sand, Snow, or Spray raised by the wind to 6 feet or more• SH – Showers• TS – Thunderstorm• FZ – Freezing• PR – Partial – Fog which covers only part of an airport


Elements - Phenomena• Precipitation• DZ – Drizzle• RA – Rain• SN – Snow• SG – Snow Grains• IC – Ice Crystals• PL – Ice Pellets• GR – Hail (¼ inch or larger)• GS – Small Hail or Snow Pellets (less than ¼ inch)• UP – Unknown Precipitation (Automated Only)


Elements - Phenomena• Obscuration• BR – Mist (visibility 5/8 sm up to and including 6 sm)• FG – Fog (visibility < 5/8 sm)• DU – Dust • SA – Sand• HZ – Haze• PY – Spray• VA – Volcanic Ash• FU - Smoke


Elements - Phenomena• Other• PO – Dust/Sand Whirls• SQ – Squalls• FC – Funnel Cloud• +FC – Tornado• SS – Sandstorm• DS – Dust Storm


Examples• TSRA• +SN• -RA FG• VCSH


Elements - Sky Condition• SKC – Sky Clear• CLR – Clear Below 12,000• FEW – Few - > 0 but < 2/8• SCT – Scattered – 3/8 to 4/8• BKN – Broken – 5/8 to 7/8• OVC – Overcast – 8/8• VV – Vertical Visibility (indefinite ceiling)


Elements - Sky Condition (Height)• Height (AGL)• 002 – Two Hundred Feet• 020 – Two Thousand Feet• 200 – Twenty Thousand Feet

• 000 – Obscuration below 50 feet (Partial Obscuration)• /// - Obscuration below station elevation


Elements – TDS and Pressure• Temperature / Dew Point• Altimeter


Elements – Remarks• Remarks are appended to the end of the METAR as required

• Examples• DSNT – Distant – Phenomena beyond 10 sm• TCU – Towering Cumulus• CB - Cumulonimbus


METAR Overview• Positives• Reported hourly• Observations• Concentrated information

• Negatives• AUTO• Not always updated• $


Sample METAR No. 1• KORD 270551Z 28008KT 10SM FEW037 M04/M08 A3020 RMK AO2

SLP235 T10391083 11022 21044 400221044 51013

• KMIA 270553Z COR 13013KT 8SM SCT024 BKN030 BKN100 OVC250 23/19 A3005 RMK AO2 SLP176 T02330194 10239 20228 56016


Sample METAR No. 2• KSEA 270553Z 11007KT 5SM -RA BR FEW015 OVC030 12/10 A3027

RMK AO2 RAB31 SLP258 P0001 60002 T01170100 10122 20111 52009

• KDFW 270553Z 35008KT 10SM SCT170 SCT240 04/M01 A3033 RMK AO2 SLP271 T00391011 10083 20039 400940039 51009


Sample METAR No. 3• METAR KABC 121755Z AUTO 21016G24KT 180V240 1SM

R11/P6000FT -RA BR BKN015 0VC025 06/04 A2990 RMK A02 PK WND 20032/25 WSHFT 1715 VIS 3/4V1 1/2 VIS 3/4 RWY11 RAB07 CIG 013V017 CIG 017 RWY11 PRESFR SLP125 POOO3 6OOO9 T00640036 10066 21012 58033 TSNO $


PIREPS• PIREP’s are inflight weather observations made by pilots• PIREP’s are the only means or observing icing and turbulence

•How to give one• Stay in the system for 6 hours


PIREPS - ElementsUA / UUA Pilot Report / Urgent Pilot ReportOV LocationTM Time (Zulu)FLAltitude / Flight LevelTP Type of AircraftSK Sky CoverWX Weather and Flight VisibilityTA TemperatureWV WindTB TurbulenceIC IcingRM Remarks


PIREPS - Turbulence• Light• Aircraft – momentarily causes slight, erratic changes in altitude and/or

attitude• Occupants may feel a slight strain against belts or shoulder straps• Unsecured objects may be displaced slightly• Food service may be conducted and little or no difficulty is encountered in

walking


PIREPS - Turbulence• Moderate• Aircraft – changes in altitude and/or attitude occurs but the aircraft remains

in positive control. Usually causes variations in indicated airspeed.• Occupants feel definite strain against seat belts or shoulder straps• Unsecured objects are dislodged.• Food service and walking are difficult.


PIREPS - Turbulence• Severe• Aircraft - large, abrupt changes in altitude and/or attitude. It usually causes

large variations in indicated airspeed. Aircraft may be momentarily out of control.• Occupants are forced violently against seat belts or shoulder straps.• Unsecured objects are tossed about.• Food service and walking are impossible.


PIREPS - Turbulence• Extreme• Aircraft – violently tossed about and is practically impossible to control. It may

cause structural damage.


PIREPS - Icing• Trace – Ice becomes perceptible• Light – Rate of accumulation may create a problem if flight is prolonged in this

environment (over 1 hour).• Moderate – Rate of accumulation is such that even short encounters become

potentially hazardous.• Severe – Rate of accumulation is such that deicing/anti-icing equipment fails to

reduce or control the hazard.


PIREPS - Overview• Positive Elements• Actual Observations• Cloud tops• Pilots make them

• Negative Elements• Aircraft type• No one makes them!• Could have been a fast moving system


PIREPS - Samples• SAN UA /OV SAN/TM 0533/FLUNKN/TP B737/RM FAP RW27 30KT

TAILWIND 060-030 AND 10KT TAILWIND 020

• PAE UA /OV PAE370040/TM 0424/FL240/TP CRJ/TB LGT OCNL MOD/RM -ZSE

• EWR UUA /OV JFK270010/TM 0430/FL130/TP B738/TA M09/IC SEV RIME


Radar Reports• Textual presentation of precipitation observed• Symbols• R Rain RW Rain Shower• S Snow SW Snow Shower• T Thunderstorm


Radar Reports – Echo Patterns• Echo Patterns• Line (LN) – convective echoes at least 30 miles long, at least 4

times long as it is wide, and at least 25% coverage within the line• Area – group of echoes of similar type• Cell – single isolated convective echo


Radar Reports – Station Status• Plan Position Indicator• PPINE – Radar is Operating Normally (No echoes observed)• PPINA – Radar Observation is not available• PPIOM – Radar is inoperative or out of service for maintenance• AUTO – Automated radar report from WSR-88D


Radar Reports - Example• GFK 1934 LN 8 TRW++/+

86/40 164/60 199/115 15W L2425 MT 570 AT 159/65 2 INCH HAIL RPRTD THIS CELL


Terminal Area Forecast• Expected meteorological conditions within a 5 sm radius from the

center of an airports runway complex • Valid for 24 hours from time of issuance• Issued 4 times a day

• 0 z, 6 z, 12 z, 18 z

• Uses same codes for weather as METAR’s


Terminal Area Forecast - Elements• ICAO Station Identifier• Date and Time of Issuance• Valid Period Date and Time• Wind Forecast• Visibility Forecast• Significant Weather Forecast• Sky Condition Forecast


TAF – Forecast Change Indicators• From (FM) Group• Used when a rapid and significant change, usually occurring in less than 1

hour

• Becoming (BECMG) Group• Gradual change in conditions is expected over a period not to exceed 2 hours

• Temporary (TEMPO) Group• Phenomenon expected to last for generally less than an hour at a time

(occasional) and expected to occur during less than half the time period


TAF – Probabilities• Probability Forecast• PROB30 – 30% to 39% Probability

• PROB40 – 40% to 49% Probability


TAF – Overview• Positive Elements• Forecast for Airport and Vicinity• Easy to Interpret• Gives general weather picture at time of arrival

• Negative Elements• Small area• Accuracy


Area Forecasts• Issued 3 times daily• Cover large geographic areas• Used for airports which do not

have TAF’s issued• Combined with Inflight

Aviation Weather Advisories


Area Forecasts - Sections1. Communications and Product Header2. Precautionary Statements3. Synopsis – summary of the location and movement of fronts4. VFR Clouds and Weather

- 18 Hour Forecast Period- 12 Hour Specific Forecast- 6 Hour Categorical Outlook


Area Forecasts - Sample• Where to find?


Airmets (WA)• Issued for…• IFR Conditions or Mountain Obscuration (AIRMET SIERRA)• Moderate Turbulence or sustained surface winds of 30 knots or greater

(AIRMET TANGO)• Moderate Icing (AIRMET ZULU)

• Issued on a scheduled basis every 6 hours• Updates and corrections issued as necessary


Sigmets (WS)• Issued for…

• Severe Icing not associated with Thunderstorms• Severe or Extreme Turbulence• Dust storms or Sandstorms lowering surface or inflight visibilities to below 3

miles• Volcanic Ash

• Maximum Forecast Period: 4 Hours• Unscheduled – Issued as Necessary


Convective Sigmets (WST)• Issued for…• Severe Thunderstorms due to:

• Surface winds greater than or equal to 50 knots• Hail at the surface greater than or equal to 3/4 in.• Tornados

• Embedded Thunderstorms• A line of Thunderstorms

• Forecast Period: 2 Hours• Scheduled – Issued at H+55


Weather Advisories - Overview• Positives• Large Area• Cloud Tops• Advisories

• Negatives• Large Area• Harder to Read


Winds Aloft• Issued twice daily• Based on the 0Z and 12Z Radiosonde Launches

• No winds forecast within 1500 ft of the surface• No temperatures forecast within 2500 ft of the surface


Winds Aloft• Coding of Wind Direction and Speed

9900 Calm2426+03 Wind 240º at 26 knots, Temp 3º C7612-13 Wind 260º at 112 knots, Temp -13º C

• When the number is in excess of 50, the wind is in excess of 100 knots.• Subtract 50 from the first pair of numbers and add 100 to the second pair.


Winds Aloft - Samples


Surface Analysis Chart• Valid only at time of issuance• Transmitted every 3 hours• Features• Isobars• Pressure Systems• Fronts• Troughs and Ridges


Weather Depiction Chart• Valid only at time of issuance• Transmitted at 3 hour intervals beginning at 01Z• Elements

• Station Data• Cloud Height• Weather and Obscurations to Visibility• Visibility – included when 5 miles or less• Analysis

• IFR – Ceiling < 1000 ft. and/or Visibility < 3 miles• MVFR – Ceiling 1000 3000 ft. and/or Visibility 3 5 miles• VFR – Ceiling greater than 3000 ft. and Visibility > 5 miles


Radar Summary Chart• Valid only at time of issuance• Transmitted hourly at H+35• Features• Echoes• Intensity• Echo Tops• Echo Movement• Severe Weather Watch Areas


Constant Pressure Analysis• Based on 0Z and 12Z Radiosonde Launches• Issued Twice Daily• Features• Contours• Isotachs• Isotherms


Significant Weather Prognostic Chart (SigWx)• Issued 4 times daily; 0Z, 6Z, 12Z, and 18Z• Four Panel Chart• Two Top Panels: Significant Weather• Two Bottom Panels: Surface Prognostic


Satellite Imagery• Seeing the big picture for clouds• Visible vs. infrared imagery


Visible

Infrared

Making the Weather Decision• Reasons for weathering a flight• Where to go for help in making the decision• Ways to divert


Personal Weather Minimums• What are they???

• Visibility• Clouds• Wind

• As you gain more experience…


References• AC 00-45G


Weather Services. What is an Observation? Observations are raw weather data collected by some type...

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Transcript of Weather Services. What is an Observation? Observations are raw weather data collected by some type...