6. Climatology Tools

6. Climatology Tools
	Chapter 2. User's Guide

Beginning with AvnFPS 3.0, a climatology database was introduced as another guidance source to help forecasters prepare and QC their TAFs. The climatology database comprise of flat files, one for each TAF site. These files consist of NCDC yearly archives of surface observations, reformatted for fast indexing and retrieval. All of the GUIs can be started as standalone programs, from the AvnFPS Startup Menu, see Section 1, “Startup Menu”, or from the Climate button on the AvnFPS Main Monitoring GUI.

6.1. Wind Rose

This GUI displays a wind rose for a given month and hour (or a range of hours). You can also specify flight category to further refine the results.

Wind Rose

To display wind rose:

Use arrows to set month in the Month counter.
Use the arrows in the Hour counter to select an hour. If you want statistics for a range of hours, use the arrows surrounding the window labelled Num Hours label to increment/decrement the value in the text window.
Use the Sites list to pick the location of interest.
Press the Draw button to draw the wind rose.

	Note
	Given selected hour, or hour range, the total hours display is the sum of all the time intervals that match the criteria specified above.

The displayed data can be saved to a file as text or graphic and can be printed. those features are accessible through the Menu Bar.

File Menu

To save statistics to a text file:

Select the Save Stats menu item.
Type the file name in the popup dialog, then press Save.

An example output file:

KBUF Jan
HOUR:          00Z
TOTAL:       991.8
CALM:         20.7
SPEED:       0-5 kt   5-12 kt  12-20 kt    20+ kt
VRB:           0.0       0.5       0.0       0.0
349-011:       5.5      16.2       1.5       0.0
011-034:       3.2      25.5       3.5       0.0
034-056:      10.7      32.2       3.9       0.4
056-079:      11.9      49.2      16.5       0.0
079-101:       1.5      21.8       4.0       0.0
101-124:       2.2      14.5       0.0       0.0
124-146:       4.0      17.0       2.1       0.0
146-169:       6.7      29.1       3.5       2.0
169-191:       3.3      35.2      11.1       1.0
191-214:       7.1      22.6      30.4       3.4
214-236:       3.4      42.4      52.7      19.1
236-259:       7.4      59.5      96.3      52.5
259-281:       3.6      41.1      68.6       9.2
281-304:       4.0      20.5      30.7       1.7
304-326:       3.5      16.0       4.1       2.1
326-349:       3.1      21.2       5.3       0.0

HOUR:          01Z
TOTAL:       989.8
CALM:         18.1
SPEED:       0-5 kt   5-12 kt  12-20 kt    20+ kt
VRB:           0.0       0.0       0.0       0.0
349-011:       3.8      14.6       3.0       0.0
011-034:       5.2      13.4       2.8       0.0

                ...

To save image to a file:

Select the Save Image menu item.
Type the file name in the popup dialog. To specify file format, use one of the extensions: .ps, .jpg, .png. Press Save.

To print image:

Select the Print Image menu item.
If needed, type in printer destination:
lpr -P printer
If the -P option is not specified, the image will be printed on your default printer.
Press OK

To change wind speed thresholds and corresponding colors and to set number of wind directions use the Configure menu item. This will display a configuration dialog.

Configuration Dialog

To change wind speed thresholds, enter appropriate values in the 3 available windows. Number of wind speed categories cannot be changed.
To change colors, press a button to the right of the wind speed label/entry. A color editor will be shown.
Use Points menu to select number of wind rose compass points, 8, 16 or 36.

Press OK to accept the changes. You may save the changes in a file, use Save.

6.2. Ceiling and Visibility Distribution

The Ceiling and Visibility Distribution GUI displays distribution of visibility and ceiling by month, by hour, or by wind compass. The display is in a form of a histogram. Image below is hourly flight category distribution according to visibility for the July-August months at Yeager Airport in Charleston, WV. These data show the typical summer-time 'fog season' at this airport with the worst impacts to visibility occurring around sunrise with any LIFR (or worse) conditions dissipating by 14Z.

July-August Visibility Distribution by Hour at Yeager Airport

To display hourly distribution:

Select the By Hour tab, above the drawing area.
In the Element frame, select the weather element or, to display flight category, Joint toggle.
Use the arrows surrounding the Month text field, just above the drawing area. If you want results for the range of months, increment and decrement the Num Months field by using the arrows on either side.
Use the Sites list to pick the locale of interest.
Press the Draw button to draw the histogram.
There is a slider-bar widget labelled y-axis scale which allows you to stretch, or compress, the vertical axis of the plot. The software usually picks a value that makes the most effective use of the drawing canvas. By unselecting the toggle button auto below the slider-bar, this feature can be disabled.

To display monthly distribution, proceed as above, but select the By Month tab. You can now select and filter results based on a single or range of hours.

In the image below for Spokane International Airport shows at 13Z, MVFR ceiling conditions, or worse, half of the time during the months of December and January.

Monthly flight category ceiling distribution at Spokane International Airport

To display flight category by wind direction, select the By Wind Dir tab. You can select and filter results based on a single or range of hours and month.

In the image below for the Baltimore International Airport, shows in February, for a six hour period from 12Z to 17Z, that MVFR or worse conditions are likely with winds having a easterly fetch. Note the table below with the HOURS row indicating the distribution of winds during that time. In this case, west-northwest winds are most common during this period. However in the relatively infrequent situations where winds have an easterly component, there is a significant risk of MVFR or worse conditions during those times.

Flight category distribution by wind direction at Baltimore International Airport

	Note
	It may take up to a minute to retrieve statistics from climate data file. To speed up display, the toolkit uses a caching mechanism: the data is retrieved only once and then stored in a file, to be read on subsequent displays.

	Note
	If the Auto Redraw button is on, selecting a toggle or changing hour/month will force a redrawing of the results.

The displayed data can be saved to a file as text or graphic and can be printed. Those features are accessible through the Menu Bar. The menu items are the same as for Wind Rose, with the exception of Configure. To save statistics to a text file:

	Note
	The 'save stats' feature was broken when distributions by wind direction was added. This function will return has soon as resources and time allow.

To save image to a file:

Select the Save Image item.
Type the file name in the popup dialog. To specify file format, use one of the extensions: .ps, .jpg, .png. Press Save.

	Note
	Image quality is noteably better if preserved in its native postscript format. Reformatting to either PNG or JPG format degrades the quality of the image.

To print image:

Select the Print Image item.
If needed, type in printer destination:
lpr -P printer
If the -P option is not specified, the image will be printed on your default printer.
Press OK

6.3. Ceiling and Visibility Trend

The Ceiling and Visibility Trend GUI displays forecast of visibility and ceiling given initial conditions. The display is in a form of a histogram.

Visibility Trend

To display ceiling/visibility trend:

Use the Sites list for the site of interest.
Use the Date, Hour, Wind Direction, Wind Speed, Ceiling, Visibility and Precip widgets to set initial conditions. Each of the widgets contains a blue arror indicating current value and a red strip/sector which is used to set matching criteria for searching similar events in climatological database. Left button moves value or an edge of range. Middle button is used to move both value and range. In the "Wind Direction" widget use right button to toggle between wind arrow and a circle representing calm and variable wind.
You can start with the most recent METAR. Select the Get button to retrieve the observation from the text database. The Decode button initializes the selection widgets.
In the Element frame, select the weather element or, to display flight category, Joint toggle.
Press the Draw button to draw the histogram.
By default, a 6-hour forecast is displayed. You can change number of hours to 3, 6, or 12 from the Hours option menu.

The displayed data can be saved to a file as text or graphic and can be printed. Those features are accessible through the Menu Bar. To save image to a file:

Select the Save Image item.
Type the file name in the popup dialog. To specify file format, use one of the extensions: .ps, .jpg, .png. Press Save.

	Note
	Image quality is noteably better if preserved in its native postscript format. Reformatting to either PNG or JPG format degrades the quality of the image.

To print image:

Select the Print Image item.
If needed, type in printer destination:
lpr -P printer
If the -P option is not specified, the image will be printed on your default printer.
Press OK


5. Weather Plot		Appendix A. Editor Key Bindings