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Post by rich on Aug 4, 2016 14:46:22 GMT -5
7900.5C 1.8.b. Conflicting Information. In case of conflicting information, the procedures and practices in
this order take precedence. However, any applicable FAA air traffic orders take precedence over any
procedures or practices in this order that are in conflict. Such conflicts should be brought to the
attention of the originator of this order.
Does the 7900.5C not take precedence over any "other associated instructions"?
The memorandum directing CWOs/LAWRSs to enable ALDARS service 24 hours per day is an example of "other associated instructions." Vendors who do not follow this policy are in violation of the terms of the contract, and are subject to penalties which may include decertification of observers, fines, or termination of contract.
7900.5C APPENDIX J. AUTOMATED WEATHER SYSTEM OPERATION AND BROADCAST When automated weather systems are equipped with local broadcast capabilities the Air Traffic Facility must ensure that weather information being broadcast on the Automated Terminal Information Service (ATIS) and all other weather outlets are the same. Note: Automated weather system communication outlets include all radio and telephone capabilities. 1. During hours of operation, towers that have ATIS capabilities and automated weather system with broadcast capability shall: a) Ensure the last transmitted METAR/SPECI weather sequence is broadcast on the ATIS and all automated weather system communications outlets. b) Ensure ASOS/AWOS ground to air radio weather communications are not simultaneously broadcast with the ATIS. c) Ensure that the Automated Lightning Detection and Reporting System (ALDARS) is disabled. Note: Automated weather system communication outlets include all radio and telephone capabilities. 2. During hours of non-operation, towers that have ATIS capabilities and automated weather system with broadcast capability shall: a) Ensure the one minute weather sequence is broadcast on all automated weather system communications outlets; this includes any automated weather system with ATIS interface capability. b) Ensure that the ALDARS capability is enabled. Note: Automated weather system communication outlets include all radio and telephone capabilities.
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Post by rich on Aug 4, 2016 15:05:43 GMT -5
14.29.b. When ALDARS detects cloud-to-ground lightning within 5 nautical miles of the Airport Reference Point (ARP), this lightning is reported in the body of the report as TS with NO REMARK. This satisfies all regulatory requirements for reporting lightning within 5 nautical miles of the ARP. The CWO or LAWRS observer may, but are not required to, augment a remark describing the frequency and type(s) lightning observed within 5 nautical miles of the airport. The CWO should augment a remark describing the location and movement (if known) of the thunderstorm. When the ALDARS detects cloud-to-ground lightning between 5-10 nautical miles of the ARP, this lightning is reported in the body of the report as VCTS with NO REMARK. This satisfies all regulatory requirements for reporting lightning between 5-10 nautical miles of the ARP. The CWO or LAWRS observer may, but are not required to, augment a remark describing the frequency and type(s) of lightning observed between 5-10 nautical miles of the airport. The CWO should augment a remark describing the location and movement (if known) of the VCTS.
Are you sure about that?
APPENDIX D. SERVICE STANDARDS
Service Level B consists of all the elements of Service Levels C and D plus long-line runway visual
range (RVR), where connected, freezing drizzle versus freezing rain, ice pellets, and remarks for snow
depth and snow increasing rapidly, thunderstorm/lightning location, and observed significant weather
not at the station.
Service Level A airports will receive, in addition to the services described above, 10 minute long-line
RVR or additional visibility increments of 1/8, 1/16 and 0. If observed, the following elements will be
added to the observation; sector visibility, variable sky condition, cloud layers above 12,000 feet and
significant cloud types, widespread dust, sand and other obscurations, and volcanic eruptions.
To enhance air traffic control efficiency and increase system capacity, additional detail beyond Service
Level C was required at some airports. These airports were divided into two categories. The highest
category, referred to as Service Level A, includes major aviation hubs and high traffic volume airports
with average or worse weather. The remaining group of airports (smaller hubs or special airports in
other ways, that have worse than average bad weather operations for thunderstorms and/or
freezing/frozen precipitation, and/or that are remote airports) are referred to as Service Level B airports.
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Post by tornado on Aug 4, 2016 15:47:58 GMT -5
The National Lightning Detection Network (NLDN), from which the ALDARS gets lightning data, has a documented detection accuracy of cloud-to-ground lightning strikes within 200 meters in the contiguous United States, flash detection efficiency greater than 95%, and thunderstorm detection efficiency in excess of 99%, according to NWS, Vaisala, and 3rd party validation studies conducted by the University of Arizona and the University of Florida. The NWS has been using the very same lightning data provided by the NLDN that the ALDARS uses for over 20 years. The ALDARS is simply using the same lightning data for METAR/SPECI observations.
Weather Tap, Inc. uses NAPLN data, another lightning network similar to the NLDN. Looking at this radar loop from Weather Tap, one can
see lots of lightning moving over Gulfport Mississippi:
Lightningmaps.org agrees with the WeatherTap/NAPLN data:
How then, did ALDARS miss that thunderstorm?
METAR KGPT 041753Z VRB06G15KT 9SM FEW027 BKN035 OVC060 32/27 A2993 RMK AO2 SLP133 T03170267 10350 20267 58018 SPECI KGPT 041829Z 1 1/4SM +RA SCT014 BKN027 OVC075 29/25 A2998 RMK AO2 PK WND 10026/1823 RAB29 PRESRR P0010 T02940250 $ SPECI KGPT 041831Z 1/2SM +RA FEW009 BKN020 BKN034 29/25 A2998 RMK AO2 PK WND 10026/1823 RAB29 PRESRR P0027 T02940250 RVRNO $ SPECI KGPT 041835Z 08024G44KT 1/4SM +RA FG BKN011 BKN027 26/24 A2999 RMK AO2 PK WND 09044/1833 RAB29 PRESRR P0042 T02560239 RVRNO $ SPECI KGPT 041844Z VRB05G31KT 1/4SM +RA FG VV019 24/23 A3003 RMK AO2 PK WND 09044/1833 RAB29 P0076 T02440228 RVRNO $ METAR KGPT 041853Z 13013KT 1/4SM +RA FG VV015 24/22 A3000 RMK AO2 PK WND 09044/1833 RAB29 SLP157 P0142 T02390222 RVRNO $ SPECI KGPT 041902Z 18012G17KT 1SM +RA BR OVC030 24/23 A3000 RMK AO2 P0015 T02440228 RVRNO $ SPECI KGPT 041919Z COR 18012G17KT 2SM +RA BR OVC030 24/23 A3000 RMK AO2 P0015 T02440228 RVRNO $ METAR KGPT 041953Z 24006KT 9SM SCT060 24/23 A2995 RMK AO2 RAE49 SLP139 P0033 T02440228
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Post by hlsto2 on Aug 4, 2016 15:52:18 GMT -5
where did that 14.29.b.come from? it's not in 7900.5C. the FAA contract specifies that all CWO's perform at the service level A requirement. it is required that we augment for ltg frequency, type, and location as well as TS location and movement
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Post by rich on Aug 4, 2016 15:57:09 GMT -5
That had to be one of those 1% of the times that ALDARS missed a TS tornado. These same folks will tell you ASOS is 98% reliable, it's just a coincidence that ALDARS missed the LTG and the winds went out here. METAR KGPT 041753Z VRB06G15KT 9SM FEW027 BKN035 OVC060 32/27 A2993 RMK AO2 SLP133 T03170267 10350 20267 58018 SPECI KGPT 041829Z 1 1/4SM +RA SCT014 BKN027 OVC075 29/25 A2998 RMK AO2 PK WND 10026/1823 RAB29 PRESRR P0010 T02940250 $ SPECI KGPT 041831Z 1/2SM +RA FEW009 BKN020 BKN034 29/25 A2998 RMK AO2 PK WND 10026/1823 RAB29 PRESRR P0027 T02940250 RVRNO $ SPECI KGPT 041835Z 08024G44KT 1/4SM +RA FG BKN011 BKN027 26/24 A2999 RMK AO2 PK WND 09044/1833 RAB29 PRESRR P0042 T02560239 RVRNO $ Read more: wxobservers.freeforums.net/posts/recent#ixzz4GOo2kiiP
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Post by rich on Aug 4, 2016 17:08:48 GMT -5
This is in accordance with 7900.5C paragraph 14.29.b. When ALDARS detects cloud-to-ground lightning within 5 nautical miles of the Airport Reference Point (ARP), this lightning is reported in the body of the report as TS with NO REMARK. This satisfies all regulatory requirements for reporting lightning within 5 nautical miles of the ARP. The CWO or LAWRS observer may, but are not required to, augment a remark describing the frequency and type(s) lightning observed within 5 nautical miles of the airport. The CWO should augment a remark describing the location and movement (if known) of the thunderstorm. When the ALDARS detects cloud-to-ground lightning between 5-10 nautical miles of the ARP, this lightning is reported in the body of the report as VCTS with NO REMARK. This satisfies all regulatory requirements for reporting lightning between 5-10 nautical miles of the ARP. The CWO or LAWRS observer may, but are not required to, augment a remark describing the frequency and type(s) of lightning observed between 5-10 nautical miles of the airport. The CWO should augment a remark describing the location and movement (if known) of the VCTS. When the ALDARS detects cloud-to-ground lightning between 10-30 nautical miles of the ARP, this lightning is reported in the remarks of the report as "LTG DSNT xx", where xx is the direction from the ARP. This satisfies all regulatory requirements for reporting lightning between 10-30 nautical miles of the airport. The CWO or LAWRS observer shall not turn off automated lightning remarks to replaced them with a manual lightning remark. wxmatrix can you tell me where I can find the bolded instructions above? This is all that 7900.5C 14.29.b says: b. When lightning is detected by an automated weather observing system with ALDARS: (1) Within 5 nautical miles of the Airport Reference Point (ARP), it will be reported as "TS" in the body of the report with no remark; (2) Between 5 and 10 miles of the ARP, it will be reported as "VCTS" in the body of the report with no remark; (3) Beyond 10 but less than 30 nautical miles of the ARP, it will be reported in remarks as "DSNT" followed by the direction from the ARP. Thanks
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Post by tornado on Aug 4, 2016 22:08:00 GMT -5
This whole VCTS issue is misleading. It's not a thunderstorm if the detected lightning is 5-10 miles away? What about the winds? Cedar Rapids, Iowa, Thu 4 Aug 2016 (tonight):SPECI KCID 050038Z 13005KT 7SM -TSRA FEW075 OVC100 28/27 A2982 RMK AO2 LTG DSNT W-NE RAE03B35 TSB32 P0002 T02780267 METAR KCID 050052Z 11003KT 9SM VCTS BKN100 28/27 A2984 RMK AO2 LTG DSNT ALQDS RAE03B35E49 TSB32E47 SLP096 P0002 T02780272 SPECI KCID 050104Z 35025G43KT 10SM -TSRA SQ FEW024 SCT035 OVC100 24/21 A2991 RMK AO2 PK WND 34043/0101 LTG DSNT ALQDS RAB04 TSB04 PRESRR P0000 T02390211 The "thunderstorm" (TS) officially "ended" at 0047Z, after which VCTS was reported in the METAR. Yet, before another thunderstorm (TS) began at 0104Z, the VCTS produced a wind gust to 43 knots! The VCTS produced stronger winds than did the TS. That happens fairly often. Maybe it's time to ditch the idea of VCTS, and go back to reporting every thunderstorm as TS. Dubuque, Iowa:SPECI KDBQ 050049Z AUTO 29022G41KT 10SM VCTS SCT023 BKN034 27/24 A2992 RMK AO2 PK WND 29041/0049 LTG DSNT ALQDS PRESRR METAR KDBQ 050053Z AUTO 32030G47KT 6SM -TSRA BR SQ FEW016 SCT023 BKN034 23/21 A2993 RMK AO2 PK WND 30047/0050 LTG DSNT ALQDS RAB51 TSB53 PRESRR SLP129 P0000 T02330211 The peak wind in that "thunderstorm", came 3 minutes before the TS began; i.e., while a VCTS was in progress. It would be better to handle thunderstorms, as Rockford, Illinois did: SPECI KRFD 050213Z 02003KT 10SM TS BKN034CB BKN080 OVC095 27/23 A2990 RMK AO2 TSB12 CONS LTGIC VC W-N TS VC W-N MOV SE T02720228 SPECI KRFD 050242Z 29015G36KT 1 1/2SM R01/4000VP6000FT +TSRA FEW027 BKN034CB OVC055 22/19 A2998 RMK AO2 PK WND 29036/0236 RAB21 TSB12 PRESRR CONS LTGICCCCG OHD TS OHD MOV SE P0002 T02220194 $ One of the biggest hazards thunderstorms produce, is their gust fronts. Aurora, Illinois was struck by a gust front tonight, well in advance of the nearest cloud-to-ground lightning: The lightning data was from 0330Z, the radar data from 0331Z. Note the time of the peak wind at Aurora (KARR): METAR KARR 050252Z AUTO 17005KT 8SM CLR 26/22 A2990 RMK AO2 LTG DSNT NW SLP119 T02560217 51008 METAR KARR 050352Z AUTO 33019G30KT 9SM FEW030 SCT044 BKN060 24/19 A2997 RMK AO2 PK WND 30036/0337 WSHFT 0333 LTG DSNT W-N SLP144 T02390194 The strongest wind struck the airport, while the lightning was still DSNT- before even a VCTS began.
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sunny9
Junior Member
Posts: 53
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Post by sunny9 on Aug 4, 2016 22:18:00 GMT -5
Actually, WeatherTap uses a different lightning detection vendor than ASOS. They use North American Precision Lightning Network (NAPLN. See www.weathertap.com/guides/lightning/lightning-strike-tutorial.html and www.uspln.com/index2.html. ASOS uses Vaisala. Sometimes Vaisala reports more LTG than NAPLN, sometimes the reverse. Rarely are both the same. About the ASOS TSB/E times, in the software before version 3.10, VCTS or TS beginning would trigger the TSB RMK. A change with version 3.10: only TS beginning triggers the TSB RMK. VCTS beginning or ending does not cause the TSB/TSE RMK in 3.10.
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Post by zoomthundersnow on Aug 4, 2016 22:29:59 GMT -5
wxmatrix, in the interest of safety, and reviewing ADDS/METARS information, and due to the fact I understand how ALDARS works, why are certain LAWRS sites allowed to continually operate in an environment where Thunderstorm information is not available, TSNO? My guess is these sites are focusing on their primary duty of the separation of air traffic. I'm not here to find fault, after the fact, but once again in the interest of safety, I'm taking a proactive approach vs. a reactive approach. For the Safety Risk Management strategy to actually work, all parties must have a voice, valid evidence must be provided, and an educated neutral panel can then decide. Maybe an SRMP can be held on ALDARS, so everyone can be educated on how it actually works. Thanks for your time.
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Post by skobie on Aug 5, 2016 0:22:25 GMT -5
Do AUGMENTED CWO stations actually report VCTS? I never have or ever will? If I see lightning (with my own eyes), I listen for thunder. If I hear thunder, I will put a TS in the body and lightning frequency, type, and direction in remarks (along with required TS remarks). This just happens to start to occur when a lightning strike is at or about 10 miles from my station in which case I will use VC for the lightning distance at this point because of the lightning/TS distance. Granted I've heard the thunder by this time, but how is ALDARS really helping me at this point? If I let it report, it's going to tell me that there is a thunderstorm that is not really at the station, but is sort of close by (ala VCTS)? What would be the point?
The VCTS becomes useless to me and if a thunderstorm is that close, you better have started a TS by this time because as we all know, that's a safety problem for my station, not to mention that lightning could easily and at any time arc right over the airport from this distance of the parent CB. Unless the noise level at the airport is too high, from experience I will generally hear thunder and report a TS at this point and if I deem the airport noise restricted my ability to hear the thunder, I will report a TS anyway and not let ALDARS run my observation by reporting a VCTS. It's a computer program regardless and is only as good as the person who wrote it and in the context of software (no matter how many revisions they make) that interfaces with a 30+ year old computer.
Remember, you (the observer) are responsible for determining if a sensor is not only working correctly (ASOS may not know one of its sensors is not working correctly every time), but just as importantly, is representative. If it's not, we turn it OFF. That's why we're here as CWOs. To man the machine, not let the machine man us. As far as ALDARS and the like goes, they're great tools to have in your arsenal, but certainly are not going to be representative all the time.
By the way wxmatrix, you seem to be "in the know" about ALDARS and how it affects the CWO program. Who is your contractor? They seem to be doing a great job educating you and your fellow observers at your CWO station. Of course, you may have researched all of this information yourself, but you seem to have a knack for pulling down references like no other and I have to assume that your contractor has given you some of this information at some time, even if inadvertent. I'd love to know who they are. We should all be so lucky. Feel free to PM me.
skobie
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Post by oldwxdude on Aug 5, 2016 0:41:08 GMT -5
Don't 14.29.a. and 14.29.b. address something different? Manual and automated stations? If that's the case then 14.29.a. reads "When lightning is observed at a manual location, the frequency and location must be reported." 14.29.b. reads "Within 5 nautical miles of the Airport Reference Point (ARP), it will be reported as...". Now, 7900.5C differentiates between must 1.8.c.(1) “Must” indicates a procedure or practice that is mandatory at all applicable facilities and will 1.8.c.(4) "Will" indicates futurity; it is not a requirement to be applied to current practices.
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Post by hlsto2 on Aug 5, 2016 1:16:41 GMT -5
our CWO...like most I look at...does not use VCTS in present wx. If a TS is 5-10 miles from ap we input...TS in present wx and FRQ LTGICCG VC SW TS VC SW MOV NE (for example.) I use weathertap live lightning. I have a 5 mile and a 10 mile ring around our ap. as soon as I see a ltg hit between 5-10 miles on the graphic, I do as the above example. no...I do not get a kickback from weathertap. It is a fantastic visual aid as we are surrounded by 2 and 3 story buildings and hangars. always go outside anyway to check for in cloud...cloud to cloud and cloud to air ltg as the program only shows cloud to ground strikes.
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Post by hlsto2 on Aug 5, 2016 1:48:36 GMT -5
ok...so here is a lawrs site that obviously lets ALDARS do it all. ALDARS ends a TS in remarks when the TS moves more than 5 miles from the ap. then ASOS takes a speci when the TS moves back within 5 miles of the ap. if the FAA demands we leave ALDARS on...can we let it put out this slop? why should CWO's have to input manual TS/LTG remarks when the lawrs sites aren't required to?
KPIA 050627Z 00000KT 4SM TSRA BR OVC090 22/21 A2995 RMK AO2 LTG DSNT ALQDS TSB19 P0011 T02170211 $ KPIA 050619Z 00000KT 2 1/2SM +TSRA BR OVC095 22/21 A2996 RMK AO2 LTG DSNT ALQDS TSB19 P0008 T02170211 $ KPIA 050554Z 29003KT 4SM VCTS RA BR OVC110 22/21 A2996 RMK AO2 LTG DSNT ALQDS TSE14B19E34 SLP140 P0008 60011 T02170211 10300 20217 403170211 53019 $ KPIA 050540Z 00000KT 7SM VCTS -RA OVC110 22/21 A2996 RMK AO2 LTG DSNT ALQDS TSE14B19E34 P0006 T02220211 $ KPIA 050454Z 29009G15KT 7SM -TSRA OVC065 22/21 A2995 RMK AO2 LTG DSNT ALQDS RAB36 TSB24 SLP137
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Post by snowspinner on Aug 5, 2016 7:39:14 GMT -5
I've been thinking about the best way to report a TS when ALDARS in on and running. I'll report a TS in present weather when it's within 10SM of the station. As far as remarks go...let the ALDARS go out and report our remarks as well. Not the best looking by any means...
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Post by weatheri on Aug 5, 2016 8:25:52 GMT -5
Let's compare:
CWO OBS KXXX 250930Z 13008G18KT 7SM -TSRA BKN030 BKN060CB OVC100 25/22 A2996 RMK AO2 PK WND 32029/0903 TSE29 FRQ LTGICCCCG VC NE-VC SE TS VC NE-VC SE MOV E P0062 T02500217 $ (Notice SPECI generated when cells moved outside of 5SM and observer hears thunder)
If left up to ALDARS KXXX 250935Z 13008G18KT 7SM -VCTSRA BKN030 BKN060 OVC100 25/22 A2996 RMK AO2 PK WND 32029/0903 LTG DSNT ALQDS TSE29 P0062 T02500217 $ (OBS sat in queue for entire 6 minutes before it transmitted / ALDARS was reporting LTG DSNT ALQDS even though the cells had already passed through the area.)
What the FAA wants the minimum augmentation for a CWO to look like KXXX 250930Z 13008G18KT 7SM -VCTSRA BKN030 BKN060CB OVC100 25/22 A2996 RMK AO2 PK WND 32029/0903 LTG DSNT ALQDS P0062 T02500217 $ (SPECI generated since cells move outside of 5SM, only required augmentation is to add CB to the SKY field, no augmentation is required for the ALDARS because it is accurate)
What it would look like to meet everyone's requirements. CWO OBS KXXX 250930Z 13008G18KT 7SM -TSRA BKN030 BKN060CB OVC100 25/22 A2996 RMK AO2 PK WND 32029/0903 TSE29 LTG DSNT ALQDS ALDARS RPTS VCTS FRQ LTGICCCCG VC NE-VC SE TS VC NE-VC SE MOV E P0062 T02500217 $ (How confusing would that be)
Yeah, I think this will cause a problem unless addressed; one of these methods adopted and the manuals changed so there is no confusion.
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