The xmacis Userʼs Guide. Keith L. Eggleston Northeast Regional Climate Center Cornell University Ithaca, NY

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1 The xmacis Userʼs Guide Keith L. Eggleston Northeast Regional Climate Center Cornell University Ithaca, NY September 22, 2004 Updated September 9, 2008

2 The xmacis Userʼs Guide The xmacis program consists of a number of routines designed to provide quick access to climatological summary products. The web-based interface makes use of frames for coincident display of user options and products. Cookies are not used and only a small amount of JavaScript is employed. The interface should work correctly on main-stream web browsers. Inputs: Station any station in the drop-down menu. The station lists consist of stations selected by the local NWS office, stations which have normals and ThreadEx stations. The station list to be used is based on the forecast office selected from the drop-down menu or specified in the xmacis URL. Variable for most routines, the available variables are maximum temperature, minimum temperature, precipitation, snowfall, snow depth, heating degree days (base 65), cooling degree days (base 65), and growing degree days (base 50). Start year the desired 4-digit starting year for the analysis. If a starting year before the beginning of a station s record is requested, most routines will set the starting year to the beginning of record. End year the desired 4-digit ending year for the analysis. If an ending year after the station s final year of record is requested, most routines will set the ending year to the last year of record. Begin date the desired starting month and day. End date the desired ending month and day. Length of period the number of days that will be accumulated (averaged or summed) for evaluation. Number of records the minimum number of values to be listed in the program output. Comparison type of comparison to be done greater than, greater than or equal to, less than, or less than or equal to. Threshold value against which the daily values are compared. There is no provision to use trace as a precipitation threshold. High/Low two choices ( highest values and lowest values ) are given. Highest values means the warmest or wettest extremes will be displayed. Lowest values will give the coldest or driest extremes. Data: The ACIS database undergoes constant revision and contains data ranging in quality from provisional to NCDC final. All products use the best available data. Timeliness of data depends on a station s reporting practices. All products use English units i.e. degrees Fahrenheit and inches. All degree days (HDD, CDD and GDD) are computed by first calculating the average temperature for the day, rounding it away from zero and then computing the difference between that value and the base temperature. ThreadEx stations (identified by the word Area in the station name) feature a combined record of weather stations within a general area to produce a longer period of record. The stations making up the threaded record may or may not be strictly compatible. More information can be found at: <

3 Routines: Monthly Averages/Totals Input: Station, variable, start year, end year. Output: Table of monthly averages or totals for each month of each year in the specified range. Monthly averages or totals are calculated depending on the variable that is selected. Monthly averages are computed for the temperature variables and snow depth. Monthly totals are computed for precipitation, snowfall and the degree day variables. Monthly statistics are based on all non-missing data available for the month. If all days in a month are missing, a dash (-) is displayed. An annual summary for each year is also provided. Monthly averages over the specified range of years are computed, along with an annual average that is the average or sum of these monthly values. For snowfall, snow depth and heating degree days, the months on the chart run from July through June. For all other variables, the year runs from January through December. Samples: ALTOONA BLAIR COUNTY AP Monthly Totals/Averages Precipitation Years: Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Avg MUSKEGON COUNTY ARPT Monthly Totals/Averages HDD (base 65) Years: Season Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Season Average

4 Monthly Frequencies Input: Station, variable, start year, end year, comparison, threshold. Output: Table of monthly frequencies for each month of each year in the specified range. Monthly frequencies are the number of days in a month that a given threshold value is exceeded. An example is the number of days/month greater than or equal to 90 degrees. Monthly statistics are based on all non-missing data available for the month. If all days in a month are missing, a dash (-) is displayed. An annual count for each year is also provided. Monthly averages over the specified range of years are computed, along with an annual average that is the sum of these monthly values. For snowfall, snow depth and heating degree days, the annual values are accumulated from July through June. For all other variables, the year runs from January through December. WAXAHACHIE Monthly Frequencies Maximum Temperature >= 90.0 Years: Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Avg

5 Monthly Extremes Input: Station, variable, start year, end year, high/low. Output: Table of monthly extreme values for each month of each year in the specified range. Monthly extremes are the highest or lowest daily values (as selected by the user) recorded in a month. Monthly statistics are based on all non-missing data available for the month. If all days in a month are missing, a dash (-) is displayed. The extreme value (highest or lowest) for each month over the specified range of years is also provided. For snowfall, snow depth and heating degree days, the months on the chart run from July through June. For all other variables, the year runs from January through December ALTA Monthly Extremes Highest Daily Snowfall Years: Season Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Extreme

6 Calendar Day Averages Input: Station, variable, start year, end year. Output: Table of daily averages for each day of the year. The daily averages are the straight average of all occurrences of the specified variable for the day in question over the specified range of years. A leap day (February 29) value will be computed, if there is at least one leap year in the range of years. A note at the bottom of the output reports the number of non-missing years available for analysis (exclusive of leap days). POCAHONTAS Calendar Day Averages GDD (base 50) Years: Day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Based on 50 to 54 years of data

7 Calendar Day Frequencies Input: Station, variable, start year, end year, comparison, threshold. Output: Table with number of years in which a value exceeded the threshold for each day of the year. Daily frequencies are the number of times over a range of years that a given threshold value is exceeded on each day. A leap day (February 29) value will be computed, if there is at least one leap year in the range of years. A note at the bottom of the output reports the number of non-missing years available for analysis (exclusive of leap days). BARROW W POST-W ROGERS ARPT Daily Frequencies Minimum Temperature < 0.0 Years: Day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Based on 53 to 55 years of data

8 Calendar Day Extremes Input: Station, variable, start year, end year, high/low. Output: Table of daily extreme values for each day of the year. Daily extremes are the highest or lowest daily values (as selected by the user) recorded on each day over a range of years A leap day (February 29) value will be computed, if there is at least one leap year in the range of years. A note at the bottom of the output reports the number of non-missing years available for analysis (exclusive of leap days). HILO INTERNATIONAL AP Calendar Day Extremes Highest Precipitation Years: Day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Based on 52 to 55 years of data

9 Daily/Monthly Normals Input: Station, variable. Output: Table of daily and monthly normals. The daily and monthly normals reported are the official normals from the National Climatic Data Center for the period. Normals are not available for every station. Snowfall normals, in particular, are only available for first-order stations. Monthly normals are calculated independently of the daily normals, so monthly totals/averages might not exactly match the sum/average of the daily values. DAYTONA BEACH INTL AP Daily Climate Normals Maximum Temperature Day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Sum/average of daily normals might not match monthly normal due to rounding

10 Extremes Input: Station, variable, start year, end year, begin date, end date, length of period, number of records, high/low. Output: List of most extreme values recorded during period. All x-day periods are examined between the beginning and ending dates specified, where x is the specified length of period. For temperatures and snow depth, the daily values are averaged; for all other variables, they are totaled. The most extreme highest or lowest results are displayed. The length of the list that is displayed is specified by the number of records selection. The rank that is assigned to a group of tied values is the lowest rank. The ending date that is listed is the ending day of each accumulation period. TUCUMCARI 4 NE Extremes Highest Average Maximum Temperature Days: 1/1-12/31 Length of period: 7 days Years: Rank Value Ending Date /30/ /29/ /2/1994, 6/30/1998, 7/1/ /1/ /4/1957, 6/28/1980 Ending Date is the last day of the 7-day period. Consecutive Days Input: Station, variable, start year, end year, number of records, comparison, threshold. Output: List of longest strings of consecutive days recorded during period. The selected variable is analyzed for strings of consecutive days meeting the selection criterion (comparison and threshold). Missing values will end a run. The longest such runs of days are reported. The length of the list that is displayed is specified by the number of records selection. The rank that is assigned to a group of tied values is the lowest rank. The end date that is listed is the last day of the run. FLINT BISHOP INTL ARPT Consecutive Days Snow Depth >= 1.0 Years: Rank # Days End Date / 3/ /22/ / 9/ / 3/1979 End Date is the last day of the run

11 First/Last Dates Input: Station, variable, start year, end year, comparison, threshold. Output: List of first and last occurrence dates and length of period for each of the specified years. The dates of the first and last occurrence of a given event are calculated for each year. The season start date for minimum temperature, snowfall, snow depth and HDD is August 1. That is, the program begins looking for the first occurrence of the search criterion (comparison and threshold) on August 1 and looks forward through time until it finds an occurrence. It begins looking for the last occurrence beginning on July 31 and works backward through time. For the other variables, the program works in a similar way, except the season start date is January 1. Therefore, it starts looking for the first date beginning January 1 and looks for the last date beginning December 31 and works backward. When searching for occurrence dates, the program looks forward (or backward) up to 12 months. If 18 or more days of missing data are encountered or 12 months are searched before an occurrence is found, the occurrence date for that year is set to missing (-). The Length column gives the number of days between (but not including) the date in the second column and the date in the third column. Samples: CAMP PICKETT First/Last Dates Minimum Temperature <= 28.0 Years: Year Last First Length 1991 Apr 4 Nov Apr 7 Oct Mar 20 Nov Apr 8 Oct Apr 15 Nov Apr 10 Nov Apr 11 Oct Mar 25 Nov Mar 23 Nov Mar 19 Oct MEDICINE BOW First/Last Dates GDD (base 50) > 5.0 Years: Year First Last Length 1991 May 8 Oct Apr 28 Oct May Apr 24 Sep Jun 2 Oct Apr 24 Oct May 7 Oct May 17 Sep Jun 1 Oct Apr 5 Oct

12 Daily Data for a Month Input: Station, year, month. Output: Listing of daily data for each day of the specified month. For each day of the month, the maximum temperature, minimum temperature, average temperature, HDD, CDD, precipitation, snowfall and depth of snow on the ground are displayed. An M indicates missing data and a T indicates a trace (of precipitation, snowfall or snow on the ground). The summary line at the bottom of the chart provides the temperature averages, degree day totals, precipitation and snowfall totals and average depth of snow on the ground. A message is given if no data for the selected month exists for the station in the ACIS database. HARTFORD BRADLEY INTL AP Observed Daily Data Month: Aug 1955 Day MaxT MinT AvgT HDD CDD Pcpn Snow Snwg M M M M M M M M T T Smry

13 Almanac Data for a Day Input: Station, year, month, day. Output: Listing of climate data for a specified day and month-to-date. The maximum temperature, minimum temperature, average temperature, HDD, CDD, precipitation, snowfall and depth of snow on the ground are displayed for the specified day in the Observed column. Also displayed are the normal values for the day, the record values for the day and their year of occurrence, and the observed values for the previous year. An M indicates missing data and a T indicates a trace (of precipitation, snowfall or snow on the ground). This same information is also provided for the month-to-date (i.e. first day of the month through date of interest). Records are the highest values on record, except for minimum temperature, which is the lowest on record. A plus sign (+) indicates that the record listed occurred in more than one year. In such cases, the last year of occurrence is listed. SYRACUSE HANCOCK INT'L ARPT Daily Almanac Date: Mar 14, 1993 Daily Values Observed Normal Record/Year Last Year Max Temperature in Min Temperature in Avg Temperature in Precipitation in New Snowfall in Snow Depth in HDD (base 65) in CDD (base 65) in Month-To-Date Observed Normal Record/Year Last Year Avg Max Temperature in Avg Min Temperature in Avg Temperature in Total Precipitation in Total Snowfall in Avg Snow Depth in Total HDD in Total CDD in indicates record also occurred in previous years (last occurrence listed)

14 Temperature Graphs Input: Station, year, start month, end month. Output: Graph of daily maximum/minimum temperatures for date range, normals, and extremes. A graph depicting the daily maximum and minimum temperatures for the specified time period (not to exceed 12 months) is displayed. These values are connected by blue lines. Also displayed are the normal maximum and minimum temperatures for each day (area between shaded in tan). Record maximum temperatures for each day are plotted in red and record minimum temperatures for each day are plotted in light blue. Graphs are png files displayed in the results frame

15 Precipitation Graphs Input: Station, year, start month, end month. Options for normal, wettest year, driest year, any other year. Output: Graph of daily precipitation accumulations. A graph depicting the daily precipitation accumulation for the specified time period (not to exceed 12 months) is displayed as a blue line. The normal precipitation accumulation for the same time period can optionally be displayed in red. The record wettest accumulation for the specified time period can optionally be plotted in green. The record driest accumulation for the specified time period can optionally be plotted in tan. The daily precipitation accumulation for any other year can optionally be plotted in magenta. Lines will be disjoint over periods with missing data. When determining the wettest and driest periods, years with more than 3% of the data missing during the period of interest are excluded. The years with the wettest and driest periods are specified below the graph, as well as, the period or record available for determining these extremes. Graphs are png files displayed in the results frame

16 Daily Data Listing Input: Station, start date, end date. Output: Listing of climate data for a range of dates. File can be downloaded or displayed. For each day in the range of dates, the daily maximum temperature, minimum temperature, precipitation, snowfall and depth of snow on the ground are listed. There is one record (row of data) per day. When the file has been prepared, a link will be displayed in the output frame of the browser. Clicking on this link will display the file. Some browsers allow users to right-click or click and hold down the mouse button over the link to download the file directly - sidestepping the need to display it in the output frame. LUKUNOCH Daily Data Listing Jul 1, Jul 10, 2003 Date MaxT MinT Pcpn Snow Snwg 07/01/ /02/ T /03/ /04/ /05/ /06/ /07/ /08/ /09/ /10/ Help: Questions or comments regarding future enhancements should be directed to: xmacis@nrcc.cornell.edu