Weather Flashcards
What is a TAF?
Terminal Aerodrome forecast Same Day, Time, Group as METAR Expected WX within 5 sm from aerodrome 4 x day (0000, 0600, 1200, 1800) Forecast is for 24 hrs (1118/1218) day/time 32 large aerodrome use ICAO 30 hr format
What is a METAR?
Aviation routine weather report (French orig)
Used for current WX where TAF is future
Observers interpretation or fully “auto” A01 A02
Must be done no earlier than 15 min prior time
Date, time, group format
Typically 55-59 past hr but have seen 53 (KVGT)
Groups include:
Winds in true
Visibility
RVR if available
WX phenomena
Sky condition (ceilings)
Temp/dew point
Altimeter
Remarks
Remarks will indicate A01 or A02. A01 can determine precipitation where A02 can determine the type of precipitation I.e. Rain, sleet, snow.
Also, you will notice (SLP 236) and (T01231032). This is Sea level Pressure and temp/dew point to the tenths.
Add 10 to 236 to get SLP in hectopascals so it would be 1023.6
Break down the temp and dew point into two groups of 4. The first # will always be a 0 or 1. 0 =positive and 1=negative. For the example above temp is positive 12.3 and dew point is negative 3.2.
What is a Area Forecast?
FA
Forecast of VMC conditions in area:
Sfo, Slc, chi, dfw, Mia, bos, ak, hi, carr
Issued 3x day Contains: Product header Precautionary statement (airmet S) Synopsis=big picture 18 hr Forecast=12 hr VMC WX forecast Outlook=6 hr outlook (vfr or IFR ) Total 18 hrs
Surface analysis chart?
Computer generated from past observation
Comes out every 3 hrs
Valid time on chart is typically 2-3 hrs old
Shows:
pressure systems highs and lows
Pressure gradients with isobars (4 mb or hPa spacing) 1013 mb=1013 hPa
Frontal positions: cold, warm, stationary, occluded
Ridges and troughs
Squall lines
The first of a four panel surface analysis prognosis
Radar summary chart?
Supposedly comes out 35 past hr Composite display of many radar sites Shows echo intensities and tops Also shows cell movement with wind barb Displays precip only not clouds Used in conjunction with other reports
Winds and temps aloft chart?
Forecasted from stations all over the US Displayed as text or graphics FB(freezing breeze)=2 x day, 0000z and 1200z Valid times are stated on chart 11 common altitudes Aids pilot: Determine most favorable alt for winds Icing levels +2 to -20 Predicting turb with abrupt wind change Text is 6 digit 2607+15 Above FL240 assumed temp is neg 2703020 No wind data within 1500 of station (METAR) 9900 =light and variable If winds greater than 100 -50 from direction and +100 to speed 731960=winds 230 @ 119 kts -60c
Significant WX prognostic chart?
2 days divided into 4 12 hr time periods 0 hr (surface analysis) Prognosis 12 hr, 24, 36 and 48 hr Displays forecasted: SIGMET and airmet type WX Freezing locations Turbulence TS, hail, rain,snow with symbology (cave markings) Expected IFR conditions Frontal locations Pressure systems
Convective outlook chart?
Picture a map with lines that delineate areas of thunderstorms and convective activity by using the qualifiers: slgt, mod, high
Issued when needed
ATIS/AWOS/ASOS
All part of terminal broadcast system
ATIS=continuously broadcasted terminal information meant to reduce atc workload
Coded in phonetic letters, typically updated 53 past the hour or when sig change has occurred such as runway direction due to winds
Time, ceiling, Vis, sky phen, temp/dew, wind, alt, remarks such as rwy in use. Sometimes if the above ceiling, sky cond isn’t a factor it will be omitted
Automates surface or weather observation systems:
Up to the minute updates from WX equip on airport
If human observer present, info will be used for ATIS and METAR
Types of Thunder storms
Air Mass=short lived like monsoon caused by quick intro of moisture or temp difference
Steady State= assoc with storm fronts and continue to feed off each other
SIGMETS, convective SIGMETS, AIRMETS
WX deemed to have sig impact on all types of A/C. Expected to occur in a area of at least 3000 sq miles or an area with sig impact
Convective SIGMET: Issued as req at 55 past hr Valid up to 2 hrs Tornadoes Line of TS Surface winds >= 50 kts due to conv Hail at surface >= 3/4 " diameter
SIGMET (non convective and weird stuff) Severe icing Severe to extreme turb Dust storms/sand storms that reduce Vis lower than 3sm Volcanic ash Hurricane ( forecasted for 6 hrs)
AIRMET (think moderate not severe) issued as needed and good for 6 hrs Mod Icing (Z) Mod turb (T) Ceilings less than 1000 and Vis less than 3 as well as mountain obscuration (S) Sustained Surface winds >=30 kts
PIREPS
UA=routine
UUA=urgent
Required when encountering WX not forecasted, wind shear, or if you go missed due to WX
Formatted
UA/OV OKC 063064/TM1522/FL080/TP C172/type of WX encountered
Windshear Reports
LLWS
Sensors placed in different loc of aerodrome that can detect differences in wind
Terminal dopplar detects wind shear
Integrated Terminal WX System (ITWS)Multiple systems deliver warnings of ARENA to ATC via WX system processor
Icing and freezing level information
Icing decreases lift and increases drag
30-40%
FB winds temps aloft
Sig WX charts
UA PIREPS
