GreenKeeper, like the weather apps on your phone, uses extremely high-resolution weather models to estimate current conditions and forecast future weather. These systems combine observations from airports, weather balloons, satellites, and weather radar with sophisticated computer simulations to generate predictions with nearly one-mile spatial resolution. While these models are generally very good at estimating temperature, humidity, dew point, and other atmospheric variables, they can struggle to accurately estimate rainfall depth at a specific location.<\/p>\n
It is not uncommon for precipitation to vary significantly across a large property. I was fortunate to intern at Whistling Straits Golf Course during college. The course spans nearly two miles along the Lake Michigan shoreline in eastern Wisconsin. I specifically remember days when the northern portion of the course received substantially more rainfall than the southern portion. We called it the “Haven Split”\u2014named after the small unincorporated community of Haven, Wisconsin, located just west of the course\u2014which seemed to split storms in half like a protective shield during those summers.<\/p>\n
The “Haven Split” made irrigation scheduling and hand watering the following morning particularly challenging. How should the nightly greens irrigation program be adjusted to account for significant differences in precipitation across the property? While modern radar systems and weather models can provide better precipitation estimates than ever before, their accuracy can still be limited at the scale of a typical golf course. So why isn’t radar-estimated precipitation good enough?<\/p>[\/et_pb_text][et_pb_text _builder_version=”4.21.0″ _module_preset=”default” global_colors_info=”{}”]
Modern NEXRAD radar in the United States is an incredible technology, but it still has limitations. These systems scan the atmosphere at multiple elevation angles above the horizon. From these scans, computers generate products such as base reflectivity and composite reflectivity. Base reflectivity provides an estimate of precipitation intensity from the lowest radar scan, while composite reflectivity combines the highest reflectivity values observed throughout the atmosphere.<\/p>\n
Wind speed and direction often change with height above the Earth’s surface. As a result, precipitation that begins falling over one location may reach the ground somewhere else. Rain does not always fall straight down. Changes in wind speed and direction can transport falling rain, sleet, and snow as they make their way toward the surface.<\/p>\n
This movement of precipitation makes radar-estimated precipitation totals difficult to calculate accurately, especially near the boundary between a rain cell and dry air. It is one reason why estimated precipitation shown in a weather app or within GreenKeeper can differ significantly from the amount of precipitation actually measured at your course.<\/p>\n
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I was flying home to Nebraska recently and was fortunate enough to observe the challenge of estimating rainfall at the Earth’s surface firsthand. Strong thunderstorms were producing heavy rainfall and gusty winds on the outskirts of town. Winds aloft were from the southwest, while surface winds were from the east. It was easy to see how the falling precipitation changed direction as it descended toward the ground.<\/p>\n
High-elevation radar scans and composite radar imagery indicated that the heaviest precipitation was located on the eastern side of the storm. From the airplane, however, the situation looked different. The falling rain was being pushed westward as it approached the surface. The intense rainfall depicted on radar was actually reaching the ground several miles west of where the radar imagery suggested.<\/p>\n
This displacement creates a challenge for radar-estimated precipitation totals. Radar may correctly detect precipitation aloft, but accurately determining where that precipitation ultimately reaches the surface is much more difficult. In this case, the rain was not falling straight down. Strong changes in wind speed and direction with height caused the precipitation to drift as it fell, resulting in rainfall at the surface occurring well away from the location where the radar initially detected it.<\/p>[\/et_pb_text][et_pb_image src=”https:\/\/www.greenkeeperapp.com\/marketing\/wp-content\/uploads\/2026\/06\/Rain-Shear.png” _builder_version=”4.21.0″ _module_preset=”default” hover_enabled=”0″ global_colors_info=”{}” title_text=”Rain Shear” sticky_enabled=”0″][\/et_pb_image][et_pb_text _builder_version=”4.21.0″ _module_preset=”default” hover_enabled=”0″ sticky_enabled=”0″]
Radar and weather models provide valuable rainfall estimates, but they cannot always account for how precipitation moves and changes before reaching the ground. When rainfall estimates don’t match conditions on your course, GreenKeeper users can quickly adjust precipitation totals on the Edit Weather page to improve Water Resource Planner calculations and help GreenKeeper Insight better learn how water behaves at their facility.<\/p>\n
For the highest accuracy, install a RECON wX Station and automatically feed measured rainfall data directly into GreenKeeper. Large properties can further improve accuracy with Satellite Rain Buckets, allowing rainfall to be measured at multiple locations across the course. Because the buckets communicate directly with the primary wX Station, there is no need for cellular service or Wi-Fi at each location. Simply maintain line-of-sight and keep buckets within approximately 800 yards of the wX Station for reliable communication.<\/p>\n
When it comes to irrigation decisions, measured rainfall will always outperform an estimate.<\/p>[\/et_pb_text][et_pb_button button_text=”Shop Weather Stations and Sensors” _builder_version=”4.21.0″ _module_preset=”default” button_url=”https:\/\/www.greenkeeperapp.com\/sensors” url_new_window=”on” button_alignment=”center” hover_enabled=”0″ sticky_enabled=”0″][\/et_pb_button][et_pb_image src=”https:\/\/www.greenkeeperapp.com\/marketing\/wp-content\/uploads\/2024\/11\/wx3-scaled.jpg” _builder_version=”4.21.0″ _module_preset=”default” title_text=”wx3″ hover_enabled=”0″ sticky_enabled=”0″][\/et_pb_image][et_pb_text _builder_version=”4.21.0″ _module_preset=”default” hover_enabled=”0″ sticky_enabled=”0″][\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section]\n","protected":false},"excerpt":{"rendered":"
GreenKeeper, like the weather apps on your phone, uses extremely high-resolution weather models to estimate current conditions and forecast future weather. These systems combine observations from airports, weather balloons, satellites, and weather radar with sophisticated computer simulations to generate predictions with nearly one-mile spatial resolution. While these models are generally very good at estimating temperature, […]<\/p>\n","protected":false},"author":3,"featured_media":102139,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"on","_et_pb_old_content":"","_et_gb_content_width":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[5],"tags":[],"class_list":["post-102137","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"jetpack_featured_media_url":"https:\/\/www.greenkeeperapp.com\/marketing\/wp-content\/uploads\/2026\/06\/Screenshot-2026-06-16-231826.png","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.greenkeeperapp.com\/marketing\/index.php\/wp-json\/wp\/v2\/posts\/102137"}],"collection":[{"href":"https:\/\/www.greenkeeperapp.com\/marketing\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.greenkeeperapp.com\/marketing\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.greenkeeperapp.com\/marketing\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.greenkeeperapp.com\/marketing\/index.php\/wp-json\/wp\/v2\/comments?post=102137"}],"version-history":[{"count":5,"href":"https:\/\/www.greenkeeperapp.com\/marketing\/index.php\/wp-json\/wp\/v2\/posts\/102137\/revisions"}],"predecessor-version":[{"id":102152,"href":"https:\/\/www.greenkeeperapp.com\/marketing\/index.php\/wp-json\/wp\/v2\/posts\/102137\/revisions\/102152"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.greenkeeperapp.com\/marketing\/index.php\/wp-json\/wp\/v2\/media\/102139"}],"wp:attachment":[{"href":"https:\/\/www.greenkeeperapp.com\/marketing\/index.php\/wp-json\/wp\/v2\/media?parent=102137"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.greenkeeperapp.com\/marketing\/index.php\/wp-json\/wp\/v2\/categories?post=102137"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.greenkeeperapp.com\/marketing\/index.php\/wp-json\/wp\/v2\/tags?post=102137"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}