Conditions across northern California and southern Oregon are still being influenced by a stationary front between a low pressure system to the northwest and high pressure over the southern United States. The low pressure system is continuing to draw moisture into the area, with a plume of moisture moving to the northeast across central Siskiyou County and up into Klamath County.While other areas are getting a reprieve from showers, conditions are worth being aware of. Freezing temperatures along coastal areas and into Coos County support a freeze. While inland temperatures are not low enough for hazard products, overnight lows will be below freezing.Lingering snow and water on non-porous surfaces could refreeze, possibly making black ice on roads. Sidewalks and shallow puddles could also freeze and create possibly hazardous surface. Fog is developing in the Rogue and Umpqua valleys, with visibilities down to miles at the Roseburg airport and less than a mile at the Medford airport.#placement_573654_0_i{width:100%;max-width:550px;margin:0 auto;}var rnd = window.rnd || Math.floor(Math.random()*10e6);var pid573654 = window.pid573654 || rnd;var plc573654 = window.plc573654 || 0;var abkw = window.abkw || '';var absrc = 'https://ads.empowerlocal.co/adserve/;ID=181918;size=0x0;setID=573654;type=js;sw='+screen.width+';sh='+screen.height+';spr='+window.devicePixelRatio+';kw='+abkw+';pid='+pid573654+';place='+(plc573654++)+';rnd='+rnd+';click=CLICK_MACRO_PLACEHOLDER';var _absrc = absrc.split("type=js"); absrc = _absrc[0] + 'type=js;referrer=' + encodeURIComponent(document.location.href) + _absrc[1];document.write(''); A light blanket of snow fell upon the South Bank. photo by Linda Lee One other little bit of oddness will be present tonight into early Wednesday morning, February 5th. The closed low off the Pacific North West coast will send a shortwave disturbance onshore into South West Oregon Tuesday night, February 4th, into Wednesday morning and this could result in snow all the way to around 500 feet above sea level, just inland from the coast.It’s not out of the realm of possibility some snow makes it to sea level, but orientation of the flow (directly onshore) should keep the beaches rain. It will likely be convective, though, so some lightning and graupel or small hail could briefly cover roadways.What is a Pineapple Express?According to the National Oceanic Atmospheric Administration (NOAA): Atmospheric rivers are narrow regions in the atmosphere that transport much of the moisture from the tropics to northern latitudes. Atmospheric rivers are part of the Earth's ocean water cycle, and are tied closely to both water supply and flood risks.A well-known example of a strong atmospheric river is called the Pineapple Express because moisture builds up in the tropical Pacific around Hawaii and can wallop the United States and Canada's West Coasts with heavy rainfall and snow.Prevailing winds cross over warm bands of tropical water vapor to form this river, which travels across the Pacific as part of the global conveyor belt. When it reaches the west coast, the Pineapple Express can dump as much as five inches of rain in one day. Atmospheric rivers come in all shapes and sizes, but those that contain the largest amounts of water vapor and the strongest winds are responsible for extreme rainfall and subsequent flooding. These events can affect the entire west coast of North America, often disrupting travel and damaging property in the process.Of course, not all atmospheric rivers are disruptive. Many are weak and provide beneficial rain or high-elevation snow that provide crucial inputs to the water supplies of western communities. googletag.cmd.push(function() { googletag.display('ad-1515727'); });