Most areas from southern Missouri and northeastern Arkansas through central Illinois recorded over 1.5 inches of rain, as did parts of the Tennessee and southern Ohio Valleys, the Upper Midwest and western Great Lakes Region, the Central Gulf Coast, and northern Maine. The average annual rainfall in Death Valley is less than 2.5 inches, and the 24-hour total makes August 2022 the wettest month in Death Valley since February 2010, and more than half of all calendar years bring less rain than that 24-hour total.įarther east, many areas from the Mississippi River eastward through the Piedmont and Middle Atlantic States recorded moderate to heavy precipitation. Death Valley, CA set an all-time record for 24-hour rainfall, being doused with 1.46 inches during August 5 and 6. Across the interior West, heavy monsoon rains set records in some locales, with tropical moisture streaming much farther north and west than normal (through southern Montana, the Great Basin, and parts of the Sonoran Desert). This intricate pattern in the diurnal cycle of precipitation reflects the complex coastlines and topography of the region, both of which are challenges to global weather and climate models.Precipitation varied widely across the Lower 48 this week. Over ocean, precipitation reaches a peak at about midnight over the coastal waters but later in the morning in the open ocean. Over land, thunderstorms form in the afternoon near the coast but later in the evening further inland. Diurnal cycle of the Maritime Continentĭuring the inter-monsoon season from March to May, the heating from the sun plays a strong role in driving precipitation. In the Gulf of Mexico, precipitation is highest at noon due to the land-sea breeze. Over the Gulf Stream, the precipitation reaches a maximum in the early morning. Over the ocean, the dynamics are different. Over the Great Plains, eastward-marching nocturnal storms bring precipitation late at night and in the early morning hours. has a high average precipitation in the late afternoon and early evening. Diurnal cycle of the Contiguous United States in Summerĭriven by the ubiquitous afternoon thunderstorms that form as a result of the build-up of energy from the sun's heat, the southeastern U.S. This transformation allows us to compare the diurnal cycle between regions that are far apart without having to account for the difference in time zones. Therefore, 16:00 LST means that it is approximately 4 p.m. The data is transformed from coordinated universal time (UTC) to local solar time (LST) based on its longitude. The strength and timing of the diurnal cycle can vary considerably depending on the geography of the region, particularly in the presence of coastlines and mountains. This causes a daily cycle of precipitation that shows up clearly in animations of the diurnal cycle. Of the many different weather systems that produces precipitation, one key process is direct heating from the sun. The diurnal cycle of precipitation describes the average precipitation over the course of the day. Notable features include the annual cycle of the InterTropical Convergence Zone (ITCZ) following the motion of the Sun (with a time lag) over both land and ocean, the seasonal shift of the Asian Monsoon between South Asia in the boreal summer and Australia in the boreal winter, the North American Monsoon in the late boreal summer in northern Mexico and southwestern U.S., and the dry summer/wet winter pattern in the Mediterranean Sea area and the west coast of the U.S. The daily climatology dataset covers January 2001 to December 2018, computed as a trailing 30-day average to reduce the random noise due to isolated big events. This animation shows the average amount of precipitation that falls on each day of the year (mm/day), computed from 2001 - 2018.ĭownload this video (right-click -> Save As)