What triggers a SPECI?

[Big Pratt]

Can someone point me to a document that defines when a SPECI is required?

I know it's AUTO but was it really necessary? Esspecially a minute apart?

SPECI CYKL 021925Z AUTO 11008KT 9SM OVC009 02/01 A3024=
SPECI CYKL 021924Z AUTO 11008KT 9SM OVC010 02/01 A3024=
METAR CYKL 021900Z AUTO 10008KT 9SM OVC008 02/01 A3024 RMK SLP269=
METAR CYKL 021800Z AUTO 09009KT 9SM OVC009 02/01 A3025 RMK SLP272=
METAR CYKL 021700Z AUTO 10008KT 9SM OVC009 02/01 A3024 RMK SLP271=

BP

[HuD 91gt]

It's been a while since I've looked into any met, but is CYKL some sort of control zone where special VFR is required? from what I can see the ceiling goes up high enough to where SVFR is not required, then dips back down again below VFR. Just a guess, I havn't looked at the regs in a while.

[Shiny Side Up]

If I remember rightly a SPECI is issued whenever the conditions change from IFR to VFR or vice versa or by a change in wind speed and/or direction of +10knots or more than 30 degrees. When conditions are below VFR minimum, they're also issued when there's a change in the vis by 1/4 mile increments or a change in the RVR if available. I think - don't quote me - that AUTO stations trigger when the cieling drops below or rises above 1000' agl mark too.

[hydro]

Can someone point me to a document that defines when a SPECI is required?

I know it's AUTO but was it really necessary? Esspecially a minute apart?

SPECI CYKL 021925Z AUTO 11008KT 9SM OVC009 02/01 A3024=
SPECI CYKL 021924Z AUTO 11008KT 9SM OVC010 02/01 A3024=

The information would be in a manual of surface weather observations (MANOBS),
http://www.msc-smc.ec.gc.ca/msb/manuals ... p10_e.html

There are sometimes variations to the standard for individual stations, for example to take into consideration the different minimums for IFR approaches.

See section 10.3.5 In this case coded 10 means 1000 ft. coded 5 means 500 ft.

10.3.5.1

Ceiling. Ceiling decreases to less than or if below, increases to equal or exceed the following coded values of height; refer to par. 10.2.8.6:
(a) 15
(b) 10
(c) 5 *
(d) 4
(e) 3*
(f) 2 *
(g) The additional limit as specified in OBS Circular 2006-01

(h) The additional limit as specified in OBS Circular 2006-01

[natej]

It's been a while since I've looked into any met, but is CYKL some sort of control zone where special VFR is required? from what I can see the ceiling goes up high enough to where SVFR is not required, then dips back down again below VFR. Just a guess, I havn't looked at the regs in a while.

The requirement for SVFR is no longer dictated by ceiling. It is only determined by visibility.

As for all those specials... I dont know.

http://www.tc.gc.ca/civilaviation/publi ... ac/2-0.htm

Special VFR weather minimum and requirements applicable within control zones are found in CAR 602.117, and are summarized as follows:

Where authorization is obtained from the appropriate ATC unit, a pilot-in-command may operate an aircraft within a control zone, in IFR weather conditions without compliance with the IFR, where flight visibility and, when reported, ground visibility are not less than:

(a) 1 mile for aircraft other than helicopters; and

(b) 1/2 mile for helicopters.

[AUGER9]

It's in the AIM

http://www.tc.gc.ca/CivilAviation/publi ... htm#3-15-4

3.15.4 Special Weather Reports (SPECI)

Criteria for Taking Special Weather Reports

Special observations will be taken promptly to report changes that occur between scheduled transmission times, whenever one or more of the following elements has changed in the amount specified. The amount of change is with reference to the preceding routine or special observation.

(a) Ceiling: The ceiling decreases to less than, or increases to equal or exceed the following values of height:

(i) 1 500 ft

(ii) 1 000 ft

(iii) 500 ft

(iv) 400 ft*

(v) 300 ft

(vi) 200 ft*

(vii) 100 ft*

(viii) the lowest published minimum

(b) Sky condition: A layer aloft is observed below 1 000 ft and no layer aloft was reported below this height in the report immediately previous, or below the highest minimum for IFR straight-in landing or takeoff, and no layer was reported below this height in the report immediately previous.

(c) Visibility: Prevailing visibility decreased to less than, or increases to equal or exceed:

(i) 3 SM

(ii) 1 1/2 SM

(iii) 1 SM

(iv) 3/4 SM

(v) 1/4 SM*

(vi) the lowest published minimum

Criteria marked with an asterisk (*) are applicable only at aerodromes with precision approach equipment (i.e. ILS, MLS, ground controlled approach [GCA]), and only down to and including the lowest published minima for these aerodromes.

(d) Tornado, waterspout or funnel cloud:

(i) is observed;

(ii) disappears from sight; or

(iii) is reported by the public (from reliable sources) to have occurred within the preceding six hours and not previously reported by another station.

(e) Thunderstorm:

(i) begins;

(ii) intensity increases to become “heavy” thunderstorm; or

(iii) ends (SPECI shall be made when 15 min have elapsed without the occurrence of thunderstorm activity).

(f) Precipitation:

(i) hail begins or ends.;

(ii) freezing rain, freezing drizzle or non-showery ice pellets begin, end or change intensity;

(iii) rain, drizzle, snow, snow grains, snow pellets, showery ice pellets or ice crystals begin or end;

(iv) special observations shall be taken as required to report the beginning and ending of each individual type of precipitation, regardless of simultaneous occurrences of other types. A leeway of up to 15 min is allowed after the ending of precipitation before an SPECI is mandatory;

(v) changes in character of precipitation do not require a special observation if the break in precipitation does not exceed 15 min.

Example: –RA to RASH, SPECI not required.

(g) Wind:

(i) speed (two-minute mean) increases suddenly to at least double the previously reported value and exceeds 30 kt;

(ii) direction changes sufficiently to fulfil criteria required for a “wind shift.”

(h) Temperature:

(i) increases by 5°C or more from the previous reported value and the previous reported value was 20°C or higher; or

(ii) decreases to a reported value of 2°C or lower.

[YVR Dude]

The easy word...precipitation...if it starts to rain (or snow) a speci is generated, likewise, if it stops raining...a speci is generated...

Thats when i most notice it, anyway...

[KT111]

Can someone point me to a document that defines when a SPECI is required?

I know it's AUTO but was it really necessary? Esspecially a minute apart?

SPECI CYKL 021925Z AUTO 11008KT 9SM OVC009 02/01 A3024=
SPECI CYKL 021924Z AUTO 11008KT 9SM OVC010 02/01 A3024=
METAR CYKL 021900Z AUTO 10008KT 9SM OVC008 02/01 A3024 RMK SLP269=
METAR CYKL 021800Z AUTO 09009KT 9SM OVC009 02/01 A3025 RMK SLP272=
METAR CYKL 021700Z AUTO 10008KT 9SM OVC009 02/01 A3024 RMK SLP271=

BP

Should be happy that the computer system is being so diligent and doing what it was created to do. The two specials issued after the hour are for the ceiling changes. Can't really blame the system, that's what it's programmed to do.