Experimental CDM Convective Forecast Planning Guidance Help
Experimental Collaborative Decision Making (CDM) Convective Forecast Planning Guidance
Part 1 – Mission Connection
1. Product Description:
The Experimental Collaborative Decision Making (CDM) Convective Forecast
Planning guidance is a graphical representation of convection
meeting specific criteria of coverage, intensity, echo height, and
confidence. The Experimental CDM Convective Forecast Planning guidance
graphics are produced every 2 hours and valid at 2-, 4-, 6-, and
8-hours after issuance time. The product issuance time is approximately the bottom of the hour
preceding a strategic planning telecon
(i.e. the 1600 UTC issuance would be available at ~1530 UTC for the 1615 UTC strategic planning telecon).
The Experimental CDM Convective Forecast Planning guidance will be
automatically produced from the NOAA Short Range Ensemble Forecast
(SREF), High Resolution Rapid Refresh (HRRR), HIRES ARW models, and
will share the same format and dissemination method as the operational,
forecaster-produced Collaborative Convective Forecast Product (CCFP).
The operational CCFP is not produced during the period
from November 1 through February 28. The Experimental CDM Convective Forecast Planning guidance will be
made available during this period for user feedback.
2. Purpose/Intended Use:
The purpose of the Experimental CDM Convective Forecast Planning guidance is to aid in the
reduction of air traffic delays, reroutes, and cancellations
influenced by significant convective events. From a user’s
perspective the Experimental CDM Convective Forecast Planning guidance is designed
for strategic planning of air traffic flow management during the en
route phase of flight. It is not intended to be used for traffic flow
control in the airport terminal environment, nor for tactical traffic
flow decisions. Specifically, the Experimental CDM Convective Forecast Planning guidance is
used to support Federal Aviation Administration (FAA)-Airline CDM
planning teleconferences which occur every two hours. It is a
general strategic planning forecast baseline, as consistent as
possible, shared among all meteorological organizations responsible
for providing forecasts of convection to the air traffic managers
within the FAA and/or within commercial aviation organizations.
As part of a larger effort to improve FAA and CDM decision making, the
FAA has asked the NWS to experimentally produce the CDM Convective
Forecast Planning guidance on two points. The first is to
evaluate the need for convective weather information during the
Collaborative Convective Forecast Product “off months” of November
– February. The second is to evaluate the suitability of the
Experimental CDM Convective Forecast Planning guidance in support of
NAS strategic planning. The FAA/CDM vision is to supplement CDM
Convective Forecast Planning guidance with an event-driven,
impact-based Collaborative Aviation Weather Statement and a continual
meteorological collaboration between industry and NWS meteorologists.
The primary users of the Experimental CDM Convective Forecast Planning
guidance are FAA Traffic Flow Management and its CDM airline
industry partners. The Experimental CDM Convective Forecast Planning
guidance is the primary convective weather forecast
for collaboratively developing a Strategic Plan of Operations (SPO) during this experimental period.
The SPO is finalized during the collaborative TELCONS hosted by the
FAA Air Traffic Control System Command Center Strategic Planning Team
and conducted approximately every 2 hours immediately after the
issuance of the Experimental CDM Convective Forecast Planning
4. Presentation Format:
The Experimental CDM Convective Forecast Planning guidance is
available via the National Weather Service Telecommunications Gateway
(NWSTG) circuit in an ASCII coded text format. An example of the
Experimental CDM Convective Forecast Planning guidance ASCII
coded text message is shown in the following graphic:
The format of the fields in the above graphic are described below.
CCFP ISSUED VALID
AREA COVERAGE CONFIDENCE GROWTH TOPS SPEED DIRECTION VERT# LAT LON.... LAT[VERT#] LON[VERT#] LATT LONT
Forecast Header Format
CCFP CCFP Forecast Header (UTC) 4 Characters
ISSUED Forecast Issuance Time (UTC) CCYYMMDD_hhmm
VALID Forecast Valid Time (UTC) CCYYMMDD_hhmm
Forecast Area Format
AREA AREA Type Header 4 Characters
AREAL COVERAGE Convective Coverage Code1
Medium =2 40-74%
Low =3 25-39%
High =1 50-100%
Low =3 25-49%
GROWTH Convective Growth Code
This field will always = 3 (No Growth) (Convective Growth Code is not used in this experimental guidance)
TOPS Storm Height Code
SPEED Speed = 0 Knots = 0
(Polygon movement including speed and direction is not depicted in this experimental guidance)
VERT# Number of LAT/LON Pairs Integer
LAT[x]LON[x] Vertical Latitude and Longitude Coverage Polygon
Latitude = LAT * 10.0 degrees
Longitude = LON * -1 * 10.0 degrees
LATT LONT Longitude and Latitude of Left Center of Box
Latitude = LATT * 10.0 degrees
Longitude = LONT * - 1 * 10.0 degrees
CANADA_FLAG* CANADA OFF
* Canada is not participating in the production of the Experimental CDM Convective Forecast Planning guidance.
The Experimental CDM Convective Forecast Planning guidance is also made
available on the Aviation Weather Center (AWC) web site as an image.
Feedback will typically be collected via the survey below:
and via comments provided to the www.AviationWeather.gov
webmaster. Opportunities for face-to-face responses will occasionally occur in the context of media workshops, public outreach
For further information please contact:
National Weather Service
Aviation Weather Center
7220 NW 101st Terrace
Kansas City, MO
Part 2 – Technical Description
1. Format and Science Basis:
Algorithm Design Basics
The new CCFP was designed to mimic the human forecaster issued polygons to allow for a smoother transition
from looking at the forecaster produced product to the automated product. In this regard, a climatology
of forecaster-produced polygons was used as the basis for the algorithm design. The climatology of
forecaster-produced polygons was collected over a period of 5 years. Information from the climatology
included average polygon sizes stratified by polygon type, and convective coverage of composite reflectivity
and echo tops in each polygon type. Since composite reflectivity has a correlation with echo top, and the
CCFP is primarily an echo top forecast, it was determined that echo top would be the primary predictor of
automated product. From the climatology study it was determined that there are three main types of
polygons that a forecaster issues during the convective season.
These include: sparse coverage-low confidence, sparse coverage-high confidence, and medium coverage-high
confidence polygon. Very rarely was a solid coverage polygon issued (approximately only 4 times a season).
It was also found that the polygons drawn exceeded the minimum size criteria of 3000 sq mi. The automated
product therefore will only draw polygons similar in size to the forecaster drawn polygons.
It was found that the minimum size of a forecaster drawn polygon was more on the order of 5000 sq mi for a
medium coverage polygon and closer to 9000 sq mi for a sparse coverage polygon.
The climatology study also determined that there were distinct bins of convective coverage found in the three
main polygon types with the sparse coverage-low confidence having the lowest coverage, the sparse coverage-high
confidence having slightly more convective coverage, and the medium coverage polygons having the most.
At this time broken and solid lines of convection are not represented in the new CCFP.
The line-type information is reserved for the event-driven CAWS. The final consideration was to maintain a
common operating picture consistent with other products available at the ATCSCC. To this end, the new CCFP
contains 3 of the most recent HRRR runs, a HIRES-ARW solution, and a SREF solution.
The SREF solution uses the mean convective precipitation from all SREF members while the high resolution
models use the echo top field for the determination of polygon areas.
The weight of using 3 HRRR solutions makes the product more consistent with the CoSPA deterministic solution,
which is desirable for decision making at the ATCSCC.
The 4 high-resolution deterministic models are equally weighted to produce potential CCFP areas and then
combined with the slightly coarser SREF model to provide smoother structure. Each high resolution model
is considered by first filtering out echo top regions less than FL240, some lower echo tops are desirable for
smoothness and to account for the potential low bias in the modeling solutions. The solutions are overlaid
on each other and areas where there is substantial model agreement are identified. The algorithm requires
that at least (2/5 or 40% of the solutions) agree. The next step is to remove polygons that do not reach
minimum criteria determined by the climatology study. From the initial group of polygons that reach minimum
size criteria, the average coverage of convection (based on echo tops greater than or equal to FL250) is
calculated for each forecast member. Only forecast members that reach the climatology minimum coverages are
allowed to contribute to the final convective coverage calculation. This ensures that if a line of
convection is present in 3 of the members and the other 2 members do not have any convection that the highest
coverage polygon will be issued. The polygon is then assigned as a sparse-low, sparse-high, or medium
coverage polygon based on the historical observed coverages of the various polygon types.
It is important to note that there is a slightly different criterion for medium polygons.
Medium coverage polygons must have high coverage and be in one of the top 3 echo top bins.
Medium coverage polygons are not allowed to exist at the lowest echo top level as those are less likely to
disrupt enroute traffic. Once the polygon type is selected, the echo tops are considered and tagged with
the highest 75th percentile of echo tops from each forecast inside the polygon. The highest echo top is
used out of the 4 high-resolution members as a potential worse-case scenario. Once the polygons are
created and tagged with echo tops, the algorithm is run through an image processing step to create the
CCFP text product with latitude and longitude points of the given polygon types that can be ingested by a
variety of software.
No additional training is required to generate or use the Experimental CDM Convective Forecast Planning guidance.
The Experimental CDM Convective Forecast Planning guidance will be
available 7 days a week during the period from November 1, 2014
through February 28, 2015. The Experimental CDM Convective Forecast
Planning guidance is updated every 2 hours.
The Experimental CDM Convective Forecast Planning guidance will be available at: http://www.aviationweather.gov/ccfp
The ASCII files will be available to users via National Weather Service
Telecommunications Gateway Under the following WMO Headers:
FAUS27 KKCI - 2 Hour Forecast
FAUS28 KKCI - 4 Hour Forecast
FAUS29 KKCI - 6 Hour Forecast
FAUS30 KKCI - 8 Hour Forecast