Title: ATC Weather Briefing
1ATC Weather Briefing
Provided by Fort Rucker Weather
Operations (FRWXOPS)
2Overview
- Whats New
- Weather Equipment
- Observations
- METAR
- SPECI
- Pilot Reports
- Cooperative Weather Watch
- Weather Watches
- Weather Warnings
- Weather Advisories
- Area Weather Advisories
- Terminal Weather Advisories
3Objectives
- 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
4References
- 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
5The Local Flying Area
32,000 sq miles of airspace
Civilian Airport Base Field Stage Field
Live Fire Range
6Whats 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
7Whats 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
8Whats 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
9Whats 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.
10Whats 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
11Whats New
- Joint Environment Toolkit (JET) is coming
- Installation slated for May 2009
- Integrated wx information system that will
replace NTFS - More information to follow
12Whats 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
13Weather 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
14Weather 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
15Weather 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
16Weather 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
17Types of Observations
18Types 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."
19METAR
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
20METAR
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).
21METAR
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.
22METAR
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.
23METAR
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).
24METAR
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).
25METAR
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.
26METAR
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.
27METAR
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.
28METAR
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.
29METAR
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.
30METAR
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.
31METAR
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.
32METAR
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.
33METAR
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.
34METAR
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.
35METAR
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.
36Types 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.
37SPECI
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.
38SPECI 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.
39SPECI 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
40SPECI Criteria (Thunderstorms)
- A SPECI is required when
- A thunderstorm begins or ends
41SPECI 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.
42SPECI 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
43SPECI 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.
44SPECI Criteria (Other Criteria)
- A SPECI is required when
- A tornado or funnel cloud appears or disappears
from sight
45Pilot 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)
46Pilot 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
47Pilot 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).
48Pilot 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).
49Pilot 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).
50Pilot 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.
51Pilot 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).
52Pilot 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.
53Pilot 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).
54Pilot 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.
55Pilot 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.
56Pilot 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
57Decoding 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)
58Decoding 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)
59Decoding 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
60Decoding 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.
61Decoding 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.
62Decoding 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)
63Decoding 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.
64Decoding 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.
65Visibility 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).
66Visibility 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).
67Decoding Elements (Visibility)
Lets look at some examples.
¾
1 ¼
½
¼
PREVAILING VIS ¾ SM
68Decoding Elements (Visibility)
1 ¼
½
¾
3
PREVAILING VIS 1 ¼ SM
69Decoding Elements (Visibility)
2
2
2
2
¼
1½
2
¼
PREVAILING VIS 2 SM
70Decoding 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.
71Decoding Elements (Present Weather)
Obscurations
Visibility 5/8 SM
Visibility
72Decoding Elements (Present Weather)
Precipitation Types
¼ inch
73Decoding Elements (Present Weather)
Intensities
74Decoding Elements (Present Weather)
Descriptors
75Decoding 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)
76Decoding Elements (Sky Condition)
Sky Cover
Cloud Ceiling
77Decoding 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
78Decoding 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
79Decoding 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.
80Decoding 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.
81Decoding 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.
82Limited 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.
83Limited 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.
84Limited 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.
85Limited 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
86Cooperative 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.
87Cooperative 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.
88Cooperative 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
89Cooperative 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
90Cooperative 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
91Cooperative 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
92Weather 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.
93Weather 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.
94Weather 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
95Weather 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
96Weather 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.
97Area 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
98Area 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
99Terminal 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
100Terminal 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
101Conclusion
- Whats New
- Weather Equipment
- Observations
- METAR
- SPECI
- Pilot Reports
- Cooperative Weather Watch
- Weather Watches
- Weather Warnings
- Weather Advisories
- Area Weather Advisories
- Terminal Weather Advisories
102Test 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
103Your feedback is
Important to us
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