ATC Weather Briefing

1
ATC Weather Briefing
Provided by Fort Rucker Weather
Operations (FRWXOPS)
2
Overview

• Whats New
• Weather Equipment
• Observations
• METAR
• SPECI
• Pilot Reports
• Cooperative Weather Watch
• Weather Watches
• Weather Warnings
• Weather Advisories
• Area Weather Advisories
• Terminal Weather Advisories

3
Objectives

• To ensure all ATC personnel can take limited
  weather observations
• To ensure all ATC personnel can pass along PIREPs
  to the Weather Station
• To ensure all ATC personnel understand the
  Cooperative Weather Watch program
• To educate all ATC personnel about the weather
  equipment in the local flying area
• To educate all ATC personnel about the watches,
  warnings, and advisories issued for the local
  flying area

4
References

• AFMAN 15-111 contains United States Air Force
  METAR weather observing and reporting procedures.
• FMH-1 Federal Meteorological Handbook No. 1
  (FMH-1) establishes standard United States
  surface weather observation requirements and
  procedures for US Federal meteorological
  agencies.
• Fort Rucker Regulation 115-1 outlines Fort
  Rucker-specific weather support and procedures
• AFMAN 15-124 Meteorological Codes

5
The Local Flying Area
32,000 sq miles of airspace
Civilian Airport Base Field Stage Field
Live Fire Range
6
Whats New

• FMQ-19 weather observing system
• An ASOS-like system that automatically generates
  observations
• Supplemented/backed up by forecaster IAW Air
  Force directives
• Replaces legacy equipment like the FMQ-13
• No more LOCALS
• No more Tower/Sector Visibility remarks
• The NTFS/LWNS terminals have a new look
• Up-to-the-minute ALSG, PA, DA
• Wind displays
• Reports the CIG

7
Whats New

• FMQ-19 augmented/supplemented per AF policy
• Supplement To manually provide wx elements that
  are beyond the automated systems capability to
  measure/report
• Tornado/funnel cloud
• Volcanic ash
• Sandstorms/duststorms
• Visibility
• Hail ¾

8
Whats New

• FMQ-19 augmented/supplemented per AF policy
• Back up To manually provide wx elements when
  automated sensors are malfunctioning and are
  operationally significant
• Wind speed/direction
• Visibility/present wx
• Temperature/dew point
• Sky cover up to and including 12,000 ft
• Altimeter
• Lightning location
• Layer of clouds or obscuration below 600 ft

9
Whats New
Lets examine the new NTFS/LWNS display.
View Weather Advisories
View PIREPs
View Weather Warnings
View the TAF
When Wind is selected, the current observation
and the wind rose display.

Current altimeter, PA, Temp, and DA. Updated
every 60 seconds.
10
Whats New
NTFS/LWNS alerts the user that software updates
are available. S/W Update flashes in red.
S/W UPDATE

• Follow these steps to perform the software
  updates
• On keypad, select config
• Scroll to bottom, and select software update
• On blue grid, select yes
• Update begins and LWNS will restart
  automatically
• Repeat until SW Update no longer appears on the
  screen

11
Whats New

• Joint Environment Toolkit (JET) is coming
• Installation slated for May 2009
• Integrated wx information system that will
  replace NTFS
• More information to follow

12
Whats New

• New method of disseminating MEF amendments

FRWXOPS
KOZR Ops
HUB Radio
KOZR TowerKLOR OpsKHEY OpsKFHK OpsKSXS
OpsATTC OpsFlat Iron Ops
Active S/FMolinelli TowerAirborne Crews
13
Weather Equipment

• The following weather equipment is located on
  Cairns AAF
• FMQ-19
• Replaces legacy sensors such as the FMQ-13
• An ASOS-like system that measures wind,
  temperature, dew point, pressure (altimeter, PA,
  DA), sky condition, visibility/RVR, present
  weather, and lightning
• Will be supplemented/backed up by a forecaster
  IAW Air Force directives

14
Weather Equipment

• The following weather equipment is located on
  Shell AHP and Molinelli FARP
• TMOS-P
• An ASOS-like system that measures wind,
  temperature, dew point, pressure (altimeter, PA,
  DA), sky condition, visibility, present weather,
  and lightning
• FMQ-13
• Measures winds

15
Weather Equipment

• The following weather equipment is located on
  Hanchey and Lowe AHP
• ASOS
• An automated system that measures wind,
  temperature, dew point, pressure (altimeter, PA,
  DA), sky condition, visibility, and present
  weather
• FMQ-13
• Measures wind

16
Weather Equipment

• The following weather equipment is located on
  all active stage fields
• FMQ-13
• There are ASOSs located throughout the Local
  Flying Area
• Troy MAP
• South Alabama RAP
• Tri-County MAP
• Eufaula MAP
• Florala MAP
• Greenville MAP

17
Types of Observations

• METAR
• SPECI

18
Types of Observations (METAR)

• METAR
• A routine scheduled observation and the primary
  observation code used by the United States to
  satisfy requirements for reporting surface
  meteorological data. METAR contains a complete
  report of wind, visibility, runway visual range,
  present weather and obscurations, sky condition,
  temperature, dew point, and altimeter setting
  collectively referred to as "the body of the
  report."

19
METAR
Example of Local / NTFS Display
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
Example of Long line Display
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
20
METAR
Lets take a closer look at the components of the
METAR observation.
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
This is an hourly (METAR) report for Cairns AAF
(KOZR).
21
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The date and time of the observation is the 12th
at 1355Z.
22
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The winds are from 130 (SE) at 12 knots (KT)
with gusts (G) to 20 knots.
23
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The visibility is 2 statute miles (SM).
24
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The present weather is thunderstorm (TS) with
moderate rain (RA).
25
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The sky condition is broken at 1000 feet (BKN010)
and overcast at 2000 feet with cumulonimbus
clouds (OVC020CB). Note cloud bases are
reported in AGL.
26
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The cloud ceiling is 1,000 feet. Note cloud
ceilings are reported in AGL.
27
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The temperature is 23 Celsius, and the dew point
is 22 Celsius.
28
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The altimeter is 29.80.
29
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The remarks include AO2 The AO2 indicates the
observation is generated from an automated
system. A trailing A would indicate that the
observation is being augmented by a weather
technician.
30
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The remarks include LTG DSNT W There is
lightning to the distant west.
31
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The pressure altitude (PA) is 410 feet.
32
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The density altitude (DA) is 1775 feet.
33
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The observation was taken at 55 minutes after the
hour.
34
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The forecasters initials are AB.
35
METAR
KOZR METAR 1355Z 13012G20KT 2 TSRA BKN010
OVC020CB CIG010 23/22 ALSTG 29.80 RMK AO2 LTG
DSNT W PA 410 DA 1775 55/AB
METAR KOZR 121355Z 13012G20KT 2SM TSRA BKN010
OVC020CB 23/22 A2980 RMK AO2 LTG DSNT W SLP176
The sea level pressure (SLP) is 1017.6 millibars.
36
Types of Observations (SPECI)

• SPECI
• An unscheduled observation completed and
  transmitted as soon as possible when any special
  criteria has been observed and is the result of a
  change in one or more of the following ceiling,
  sky condition, visibility, present weather, and
  any other conditions determined to be
  significant. SPECI will contain all data
  elements found in a METAR plus additional remarks
  that elaborate on data in the body of the report.
  All SPECI reports will be prepared and
  disseminated as soon as possible after the
  relevant criteria are observed.

37
SPECI
Example of Local / NTFS Display

• KOZR SPECI 1245Z VRB02KT 1 BR BKN005 OVC010
  CIG005 04/04 ALSTG 30.18 RMK AO2 PA 68 DA 1417
  45/DR

Example of Long line Display
KOZR 251245Z VRB02KT 1SM BR BKN005 OVC010 04/04
A3018 RMK AO2
Since you would read a SPECI just like you would
read a METAR, lets move ahead and examine our
SPECI criteria.
38
SPECI Criteria (Ceiling)

• A SPECI is required when the ceiling forms
  below, decreases to less than, or if below,
  increases to equal or exceed
• 3000 feet 500 feet
• 1500 feet 400 feet
• 1000 feet 300 feet
• 800 feet 200 feet
• 700 feet 100 feet
• 600 feet
• A layer of clouds or obscuring phenomena aloft is
  present at or below 600 feet and no layer was
  reported in the preceding METAR or SPECI.

39
SPECI Criteria (Visibility)

• A SPECI is required when the prevailing
  visibility decreases to less than or, if below,
  increases to equal or exceed
• 3 SM 1 SM
• 2 SM ¾ SM
• 1 ½ SM ½ SM
• 1 ¼ SM ¼ SM

40
SPECI Criteria (Thunderstorms)

• A SPECI is required when
• A thunderstorm begins or ends

41
SPECI Criteria (Wind)

• A SPECI is required when
• A squall occurs. A squall is when the wind
  speed suddenly increases by 16 knots or more and
  exceeds 22 knots for at least 1 minute.
• Wind shift. The wind direction changes of 45 or
  more in less than 15 minutes with sustained winds
  or gusts of 10 knots or more throughout the
  shift.

42
SPECI Criteria (Precipitation)

• A SPECI is required when
• Hail begins or ends
• Freezing precipitation begins, ends, or changes
  intensity
• Any other type of precipitation begins or ends

43
SPECI Criteria (RVR)

• A SPECI is required when the Runway Visual
  Range (RVR) from the active runway (RWY 06)
  decreases to less than, or if below, increases to
  equal or exceed
• 2000 feet 5000 feet
• 2400 feet 6000 feet
• 4000 feet
• RVR conditions are unavailable (RVRNO), are first
  determined, or when RVRNO is no longer
  applicable.
• Prevailing visibility is first observed to be 1
  SM and again when prevailing visibility goes
  above 1 SM
• Note RVR for RWY06 is reported locally
  regardless of the active runway.

44
SPECI Criteria (Other Criteria)

• A SPECI is required when
• A tornado or funnel cloud appears or disappears
  from sight

45
Pilot Reports (PIREPs)

• A PIREP is defined as a report of meteorological
  phenomena encountered by aircraft in flight
• Required fields include
• Message type (UA-routine UUA-urgent)
• Location
• Time
• Flight Level
• Aircraft type
• One other element such as
• Sky cover
• Weather
• Temperature
• Winds
• Hazards (Turbulence, Icing)

46
Pilot Reports (PIREPs)

• All PIREPs received by ATC agencies must be
  passed immediately to the Weather Station

Lets look at an example.
KOZR UA /OV KOZR330010/TM 1520/FL050/TP B06/WX
FV02SM FU/TA 15/WV 06025KT/RM TOP OF SMOKE LYR AT
050 SMOOTH RIDE
47
Pilot Reports (PIREPs)
KOZR UA /OV KOZR330010/TM 1520/FL050/TP B06/WX
FV02SM FU/TA 15/WV 06025KT/RM TOP OF SMOKE LYR AT
050 SMOOTH RIDE
The PIREP was disseminated by Cairns AAF (KOZR).
48
Pilot Reports (PIREPs)
KOZR UA /OV KOZR330010/TM 1520/FL050/TP B06/WX
FV02SM FU/TA 15/WV 06025KT/RM TOP OF SMOKE LYR AT
050 SMOOTH RIDE
The PIREP is routine in nature (UA).
49
Pilot Reports (PIREPs)
KOZR UA /OV KOZR330010/TM 1520/FL050/TP B06/WX
FV02SM FU/TA 15/WV 06025KT/RM TOP OF SMOKE LYR AT
050 SMOOTH RIDE
The PIREP was from an aircrew located 10 SM NW
(330010) of Cairns AAF (KOZR).
50
Pilot Reports (PIREPs)
KOZR UA /OV KOZR330010/TM 1520/FL050/TP B06/WX
FV02SM FU/TA 15/WV 06025KT/RM TOP OF SMOKE LYR AT
050 SMOOTH RIDE
The time of the PIREP was 1520Z.
51
Pilot Reports (PIREPs)
KOZR UA /OV KOZR330010/TM 1520/FL050/TP B06/WX
FV02SM FU/TA 15/WV 06025KT/RM TOP OF SMOKE LYR AT
050 SMOOTH RIDE
The flight level was 5000 feet (050).
52
Pilot Reports (PIREPs)
KOZR UA /OV KOZR330010/TM 1520/FL050/TP B06/WX
FV02SM FU/TA 15/WV 06025KT/RM TOP OF SMOKE LYR AT
050 SMOOTH RIDE
The aircraft type was a B06.
53
Pilot Reports (PIREPs)
KOZR UA /OV KOZR330010/TM 1520/FL050/TP B06/WX
FV02SM FU/TA 15/WV 06025KT/RM TOP OF SMOKE LYR AT
050 SMOOTH RIDE
The flight visibility was 2 SM (FV02SM) due to
smoke (FU).
54
Pilot Reports (PIREPs)
KOZR UA /OV KOZR330010/TM 1520/FL050/TP B06/WX
FV02SM FU/TA 15/WV 06025KT/RM TOP OF SMOKE LYR AT
050 SMOOTH RIDE
The temperature was 15 Celsius.
55
Pilot Reports (PIREPs)
KOZR UA /OV KOZR330010/TM 1520/FL050/TP B06/WX
FV02SM FU/TA 15/WV 06025KT/RM TOP OF SMOKE LYR AT
050 SMOOTH RIDE
The wind was from the NE at 25 knots.
56
Pilot Reports (PIREPs)
KOZR UA /OV KOZR330010/TM 1520/FL050/TP B06/WX
FV02SM FU/TA 15/WV 06025KT/RM TOP OF SMOKE LYR AT
050 SMOOTH RIDE
The remarks include Top of smoke layer at 5000
feet Smooth ride
57
Decoding Elements (Wind)

• Wind direction is encoded in whole degrees to
  the nearest ten degrees magnetic locally, and in
  whole degrees to the nearest ten degrees true by
  other stations (ex 210, 030)
• Wind speed is encoded in whole knots
  (ex 07, 12)

58
Decoding Elements (Wind)

• The wind direction is considered variable if the
  wind speed is 6 knots or less and the direction
  varies by 60 degrees or more. (ex VRB06KT)
• If the speed is greater than 6 knots, the
  average direction will be encoded with the wind
  speed followed by the variable extremes encoded
  in a clockwise direction.
• (ex 16010KT 100V210)

59
Decoding Elements (Wind)

• The wind character is encoded with a G
  followed by the speed of the gust and suffixed
  with KT to make certain customers know this is
  in knots and not in miles per hour. If this
  group is not present, the suffix is after the
  wind speed (ex 16015G28KT)

Lets look at a few examples
27009KT From the W at 09 KT 33014KT From the NW
at 14 KT VRB06KT Variable at 06
KT 12015G31KT From the SE at 15 KT with gusts of
31 KT
60
Decoding Elements (Visibility)

• Surface visibility is defined as the prevailing
  visibility determined from the designated point
  of observation. It normally represents a value
  observed at a height of 6 feet (1.8 meters) above
  ground level and is reported in statute miles
  (SM).
• Tower visibility is defined as the prevailing
  visibility determined from the control tower and
  is reported in statute miles (SM).
• When reporting visibility to aircraft, ATC
  personnel must pass the lower value (tower
  visibility or prevailing visibility) to airborne
  aircraft in the local pattern.

61
Decoding Elements (Visibility)

• Prevailing visibility is defined as the
  visibility considered to be representative of the
  visibility conditions at the weather unit or
  control tower. This representative visibility
  is the greatest visibility equaled or exceeded
  throughout at least half the horizon circle, not
  necessarily continuous.
• Uniform visibility is defined as when the
  visibility is the same in all sectors, the
  prevailing visibility is simply the greatest
  distance you can see.
• Non-uniform visibility is defined as when the
  visibility is not the same in all sectors,
  visually divide the horizon into sectors of
  uniform values.

62
Decoding Elements (Visibility)

• Variable prevailing visibility is defined as the
  average of all visibility values observed
  throughout the horizon circle. A remark must be
  used showing the extremes of variability. (Ex.
  VIS ½V2)

63
Decoding Elements (Visibility)

• When the prevailing visibility value is 3 SM
  and is rapidly increasing and decreasing by ½
  mile or more during the period of observation,
  the average of all visibility values observed
  during the period of observation will be coded
  and reported. This criteria must be met in order
  to be considered Variable Prevailing Visibility.

64
Decoding Elements (Visibility)
Reportable values Distance Increment 0 - 3/8
miles 1/16th mile increments 3/8 - 2 miles 1/8th
mile increments 2 - 3 miles 1/4 mile increments 3
-15 miles 1 mile increments Over 15 miles 5 mile
increments NOTE If visibility is between two
reportable values, select the lower value of the
two as the prevailing visibility.
65
Visibility Markers

• The most suitable daytime visibility markers are
  prominent, dark (or nearly dark) colored objects
  (such as buildings, chimneys, hills, or trees)
  observed in silhouette against a light-colored
  background, preferably the horizon sky. When
  using an object located in front of a terrestrial
  background, ensure the object is located closer
  to the point of observation than it is to the
  terrestrial background.
• NOTE Moving aircraft are NOT an acceptable
  method of determining visibility. Only fixed
  objects for which the distance is known may be
  used (ie objects from your approved visibility
  chart).

66
Visibility Markers

• The most desirable night-visibility markers are
  unfocused lights of moderate intensity (about
  25-candle power). The red or green runway course
  lights of airway beacons and TV or radio tower
  obstruction lights may be used. Do not use
  focused lights such as airway beacons due to
  their intensity however, their brilliance may
  serve as an aid in estimating whether the
  visibility is greater or less than the distance
  to the light source.
• NOTE Moving aircraft are NOT an acceptable
  method of determining visibility. Only fixed
  objects for which the distance is known may be
  used (ie objects from your approved visibility
  chart).

67
Decoding Elements (Visibility)
Lets look at some examples.
¾
1 ¼
½
¼
PREVAILING VIS ¾ SM
68
Decoding Elements (Visibility)
1 ¼
½
¾
3
PREVAILING VIS 1 ¼ SM
69
Decoding Elements (Visibility)
2
2
2
2
¼
1½
2
¼
PREVAILING VIS 2 SM
70
Decoding Elements (Present Weather)

• Present Weather is typically the last element
  observed outside. It is reported for any
  phenomenon that reduces prevailing visibility to
  6 SM or less. This section will help you
  determine the present weather type, intensity,
  and descriptor. Atmospheric phenomena that
  reduce visibility are called meteors. A meteor
  is any phenomenon, other than cloud, observed in
  the atmosphere or on the surface, consisting of
  water or other particulate matter, or an optical
  or electrical manifestation. We classify
  atmospheric phenomena as precipitation or
  obscuration.

71
Decoding Elements (Present Weather)
Obscurations
Visibility 5/8 SM
Visibility
72
Decoding Elements (Present Weather)
Precipitation Types
¼ inch

73
Decoding Elements (Present Weather)
Intensities
74
Decoding Elements (Present Weather)
Descriptors
75
Decoding Elements (Present Weather)
Lets look at some examples.
FZRA freezing rain -RA light rain TSRA thunders
torm with heavy rain BLDU blowing
dust BCFG patchy fog SHRA moderate rain
showers TS thunderstorm (no rain)
76
Decoding Elements (Sky Condition)
Sky Cover
Cloud Ceiling
77
Decoding Elements (Sky Condition)
Lets look at some examples.
BKN030 Broken at 3000 feet AGL SCT002
OVC250 Scattered at 200 feet and overcast at
25,000 feet AGL VV001 Vertical visibility into a
total obscuration, in this case 100 feet AGL
78
Decoding Elements (Sky Condition)

• Ceiling is defined as the lowest non
  surface-based layer that is reported as broken or
  overcast, or the vertical visibility into a
  surface-based obscuration that totally hides the
  sky (i.e. an indefinite ceiling)

Lets look at some examples.
VV001 100 feet SCT002 BKN005 OVC010 500
feet BKN025 OVC050 2500 feet BKN250 25,000
feet
79
Decoding Elements (Temperature)

• The air temperature is reported to the nearest
  whole degree Celsius using two-digit values.
  When the temperature is below 0 Celsius, it is
  prefixed with an M to signify minus.

80
Decoding Elements (Dew Point)

• The dew point temperature is reported to the
  nearest whole degree Celsius using two digit
  values. When the dew point is below 0 Celsius,
  prefix the value with an M to signify minus. For
  example, a dew point of minus 0.2 degrees Celsius
  would be coded M00.

81
Decoding Elements (Altimeter)

• Altimeter setting defines the pressure value to
  which an aircraft altimeter scale is set so that
  the altimeter indicates the altitude above mean
  sea level of an aircraft on the ground at the
  location for which the value was determined. The
  altimeter setting is reported to the nearest
  hundredth of an inch Hg (Mercury) in four digits.

82
Limited Observations (Visibility)

• When evaluating tower visibility
• Ensure that dark or nearly dark objects may be
  viewed against the horizon during the day, and
  unfocused lights of moderate intensity (25
  candles) are used to determine visibility at
  night.
• Evaluate as frequently as practical, use all
  available markers.
• The greatest distance that can be seen in each
  direction around the horizon circle needs to be
  determined.

83
Limited Observations (Visibility)

• When evaluating tower visibility
• When visibility is greater than the furthest
  markers, estimate the visibility based upon the
  sharpness of the marker. If the outline is sharp
  and the color is good, the visibility is much
  further than the marker. If the outline is
  blurry, then the visibility is at or slightly
  greater than the marker.
• Charts must be reviewed by the weather station
  operations management section annually or when
  the visibility chart changes.

84
Limited Observations (Clouds)

• When evaluating cloud amounts
• Evaluate the amount of sky cover for each cloud
  layer or obscuring phenomena in eighths,
  beginning with the lowest layer and proceeding in
  ascending order of height. As part of your
  evaluation, always disregard cloud amounts
  visible through lower thin clouds, but include
  amounts that are visible through surface based
  obscuring phenomena. Consider initial cloud
  formation with a trace of clouds as 1/8 of sky
  cover. Smoke plumes or any other obscuring
  phenomena less than 1/8 coverage is disregarded
  in sky cover determinations. Obscuring
  phenomena, surface based or aloft, must cover 1/8
  of sky or more to be considered a layer.

85
Limited Observations (Tornadic Activity)

A waterspout is defined as a violently rotating
column of air that touches the water
A tornado is defined as a violently rotating
column of air that touches the ground

• A funnel cloud is defined as a violently rotating
  column of air that does not touch the ground

86
Cooperative Weather Watch

• Weather units responsible for preparing surface
  weather observations will establish a cooperative
  weather watch with Air Traffic Control (ATC) and
  other appropriate post agencies, as required.
• Of primary concern is the report of tower
  visibility different from the prevailing surface
  visibility reporting of sector visibility local
  PIREPs and any occurrence of previously
  unreported weather conditions that could affect
  flight safety or be critical to the safety or
  efficiency of other local operations and
  resources.

87
Cooperative Weather Watch

• The cooperative weather watch will define, at a
  minimum, the following
• The process for certified ATC personnel to
  evaluate tower visibility in order to report
  changes in tower prevailing visibility and sector
  visibility to the local weather unit when tower
  visibility is
  different from the surface prevailing visibility,
  and the process for reporting sector visibility.
• The requirement for weather technicians to
  reevaluate the weather conditions whenever a
  reliable source (i.e., ATC, pilots, local law
  enforcement, etc.) reports weather conditions
  different from the last disseminated observation.

88
Cooperative Weather Watch

• Certified tower personnel at Cairns AAF will
  notify the Weather Station
• When changing active runways
• When changing the runway center light settings
• When the prevailing visibility at the tower is 4 SM (6000 meters)
• When thunderstorms or precipitation begins or
  ends
• When fog or mist is observed
• Anytime a PIREP is received

89
Cooperative Weather Watch

• Certified tower personnel at Hanchey AHP will
  notify the Weather Station
• When a ceiling is 1000 ft and/or their
  visibility is 3 SM and is different from the
  observation at Cairns AAF
• When a cloud ceiling forms at, increases above,
  or decreases below 500 feet
• When visibility decreases below or increases
  above ½ SM
• When thunderstorms or precipitation begins or
  ends
• When fog or mist is observed
• When winds exceed 25 kts, 35 kts, and 50 kts
• Anytime a PIREP is received

90
Cooperative Weather Watch

• Certified tower personnel at Lowe AHP will
  notify the Weather Station
• When a ceiling is 1000 ft and/or their
  visibility is 3 SM and is different from the
  observation at Cairns AAF
• When a cloud ceiling forms at, increases above,
  or decreases below 500 feet
• When visibility decreases below or increases
  above ½ SM
• When thunderstorms or precipitation begins or
  ends
• When fog or mist is observed
• When winds exceed 25 kts, 35 kts, and 50 kts
• Anytime a PIREP is received

91
Cooperative Weather Watch

• Certified tower personnel at all other base or
  stage fields will notify the Weather Station
• When precipitation begins or ends
• When fog or mist is observed
• When winds exceed 25 kts, 35 kts, and 50 kts
• Anytime a PIREP is received

92
Weather Watch Criteria

• The following Weather Watches are issued as
  potential warrants
• Tornado
• LTG w/in 15NM (DLT is 60 min)
• Damaging Winds 50 kts
• Hail ½
• Heavy Rain
• 2 in 12 hrs
• Freezing Precipitation
• Snowfall
• ½ accumulation

Note Except for the LTG Watch, Weather Watches
are issued for a 60NM ring centered on Cairns
AAF.
93
Weather Watch Criteria

• The following Weather Watch is issued for Troy
  MAP and South Alabama RAP as potential warrants
• LTG w/in 15NM (DLT is 30 min)

Note Weather Warnings are issued for a 5NM ring
centered on Troy MAP or South Alabama RAP.
94
Weather Warning Criteria
The following Weather Warnings are issued for
Cairns AAF with the indicated desired lead
times
Criteria Tornado LTG w/in 5 NM Damaging Winds
50 kts Hail ½ Winds 35-49 kts
DLT 5 minutes Observed 60 minutes 60 minutes 60
minutes
Note Except for the Lightning Warning, Weather
Warnings are issued for a 15NM ring
centered on Cairns AAF
95
Weather Warning Criteria
Criteria Hail
2 in 12 hrs) Freezing Precipitation Snowfall (
½ accumulation)
DLT 60 minutes 60 minutes 60 minutes 60
minutes 60 minutes
Note Except for the Lightning Warning, Weather
Warnings are issued for a 15NM ring
centered on Cairns AAF
96
Weather Warning Criteria
The following Weather Warnings are issued for
Troy MAP and South Alabama RAP with the indicated
desired lead times
DLT 5 minutes 60 minutes 60 minutes Observed
Criteria Tornado Damaging Winds 50 kts Hail
½ LTG w/in 5NM
Note Weather Warnings are issued for a 5NM ring
centered on Troy MAP or South Alabama RAP.
97
Area Weather Advisory Criteria
The following Area Weather Advisories (AWAs) are
issued with the indicated desired lead times
Criteria Forecast severe or extreme TURBC
blo 10K ft Observed moderate or greater TURBC blo
10K ft Forecast icing blo 10K ft Winds 20 kts
DLT 60 minutes
Observed 60
minutes Observed
Note AWAs are issued for a 60NM ring centered
on Cairns AAF
98
Area Weather Advisory Criteria
Criteria LLWS blo 2K ft Observed 1500/5 in
Goldfish IFR Conditions (1000/3) observed w/in 60
NM of KOZR IFR Conditions (1000/3) forecast w/in
60 NM of KOZR Thunderstorm IFR Conditions
(1000/3) forecast w/in 60 NM of KOZR
DLT Observed Observed Observed
60 minutes 60 minutes
Note AWAs are issued for a 60NM ring centered
on Cairns AAF
99
Terminal Weather Advisory Criteria
The following Terminal Weather Advisories (TWAs)
are issued with the indicated desired lead
times
Criteria Wind gust spread 15 kts Cross winds
25 kts at Cairns AAF Temps 00C for 5 or more
hrs Temps M06C
DLT Observed Observed 60 min 60 min
Note TWAs are issued for a 15NM ring centered
on Cairns AAF
100
Terminal Weather Advisory Criteria
Criteria LTG observed w/in 10 NM of KOZR IFR
Conditions (1000/3) observed w/in 15 NM of
KOZR IFR Conditions (1000/3) forecast w/in 15 NM
of KOZR Thunderstorm IFR (1000/3) conditions
forecast w/in 15 NM of KOZR
DLT Observed Observed 60 min 60 min
Note TWAs are issued for a 15NM ring centered
on Cairns AAF
101
Conclusion

• Whats New
• Weather Equipment
• Observations
• METAR
• SPECI
• Pilot Reports
• Cooperative Weather Watch
• Weather Watches
• Weather Warnings
• Weather Advisories
• Area Weather Advisories
• Terminal Weather Advisories

102
Test Time

• Please notify Ms Howell (5-8272) if you have any
  questions or feedback about this course.
• As part of your Initial Weather Certification and
  Annual Recertification, you must take and pass a
  written exam with 70 or above.
• Tower Chiefs, please remember to email your memos
  to Ms Howell (cindy.howell_at_us.army.mil)

• Slides Updated on 28 Apr 09

103
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104
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