FXUS66 KMFR 051710 AFDMFR Area Forecast Discussion National Weather Service Medford OR 910 AM PST Tue Mar 5 2024 .DISCUSSION...Precipitation over the last hour or so has been trending downward in central and northern Douglas County based in part on the radar returns. Meanwhile steady precipitation remains in southern Douglas County, Curry, Josephine, Jackson, Klamath, and western Siskiyou Counties. Precipitation in these areas will continue through the day. However precipitation will diminish and become lighter and end altogether from northwest to southwest this afternoon. Also there was a spotter report of some flooding in portions of Josephine and Jackson County until late this afternoon. The reason for this is due to a combination of rain and snowmelt from this past weekends storm. Please see FLSMFR for more details on this. Also a winter weather advisory from 500 feet to 1500 feet is due to end at 10 am pst and this looks good. As we get further into the daylight hours, even though it will be snowing, it will likely melt on the roads moving forward. High res guidance are in pretty good agreement showing precipitation gradually shifting south this afternoon into this evening. Precipitation is expected to continue through this evening in southern Klamath and Lake County, and through the overnight hours in northern California. We'll look into the possibility of either extending the end times of the winter storm warnings for these areas, or replacing them with a winter weather advisory. -Petrucelli && .AVIATION...05/12Z TAFs...Current radar imagery shows a long band of precipitation moving northeast across the area, with more showery (isolated/intermittent) precipitation south of the band. A wide variety of flight conditions are being reported this morning, especially with snow levels of 400-1,000 feet bringing snow and low visibility in Douglas County while snow levels hover around 3,500- 4,000 feet pretty much everywhere else. The precipitation band will continue to move from the southwest to the northeast over the region this morning, slowly slumping southeast through the day. Snow will likely continue in the Umpqua Basin (including in Roseburg) this morning before lightening and then ending towards 19/20z. Meanwhile, higher snow levels in the Rogue Valley will ensure precipitation stays rain around here, but precipitation and lower ceilings will likely persist into late this afternoon. So far, visibility at Medford has been better than expected compared to what guidance has showed, so have leaned towards this continuing today. Have concerns about Klamath Falls early this afternoon due to some uncertainty in snow levels, which are hovering right around the airport's elevation. While only receiving intermittent precipitation right now, expecting the precipitation band to move into the area starting around 17/18z and strengthening towards 20/21z. Snow levels are expected to rise above the airport as this point, but it's possible that this could come in as mixed rain and snow or just snow, which could lead to periods of very poor visibility. Have included a rain snow mix and trended towards poorer visibility in this issuance to account for this. -CSP && .MARINE...Updated 900 AM Tues March 05, 2024...A low pressure system has moved ashore. Behind it, we'll see seas briefly diminish this morning into this afternoon, with breezy north winds persisting through the day. This period of relatively calm seas, however, will not last long as northerly winds increase again this evening and tonight to 15 to 25 kt and wind-driven seas start to steepen. Conditions will be hazardous to small craft through the marine waters, with the steepest seas and strongest winds south of Cape Blanco. Gusty winds will then start to move south through late Wednesday into early Thursday with seas decreasing behind them, and we'll have another brief calm period ahead of further frontal systems in the late week into the weekend. -CSP && .PREV DISCUSSION... /Issued 406 AM PST Tue Mar 5 2024/ UPDATE...Updated aviation discussion for 12z TAFs. SHORT TERM...RADAR imagery is showing precipitation across portions of southern Oregon and northern California. This is part of a larger front that is draped across the Douglas, Jackson, and Josephine County Border. The air to the north of this front is very cold and snow is being reported at the Roseburg airport. Snow levels are around 500 to 1500 feet. Meanwhile, south of the line, rain is being reported at the Medford Airport. Snow levels are around 3000 feet. The overall picture for today will be that the trough is splitting with another low pressure system digging farther south into central California which will also drag the aforementioned boundary south with it. This will allow precipitation to clear the area from northwest to Southeast through the evening with northern California as well as southern Lake and Klamath Counties holding onto precipitation chances through Wednesday evening. A plethora of Winter Storm Warnings and Winter Weather Advisories remain in effect through this afternoon. While the snow levels will fall for areas west of the Cascades through the day, expect the precipitation to largely taper off before the Illinois and Rogue Valleys see snow. (A few flurries could be possible, but impactful snow is not expected in these areas). One aspect to note is that higher resolution guidance are suggesting some precipitation forcing across the Warner Mountains this afternoon and evening. The probability of snowfall rates of an inch an hour will hold steady at 40 to 50 percent except at the highest elevations of the Warner mountains which show 1 inch per hour snowfall rate probabilities up to 70 percent. With the unstable nature of the expected showers and the splitting of the trough, am deciding to hold off on extending the current Winter Storm Warning for the Warner mountains for now. However, there is a 40 percent chance that this may need to be extended; or a little higher chance that an advisory may be needed after the main precipitation event as described in the Winter Storm Warning. Will allow the day shift to assess. -Brad LONG TERM...Previous long term discussion from 3/4 for...(Wednesday 3/6 through Monday 3/11)...A stationary front over the area will weaken and shift south during the day Wednesday. Light precipitation is favored across northern California and for areas from the Cascades east in southwest Oregon. Precipitation tapers off Wednesday evening. Northern portions of the area (Coos, Douglas, northern Klamath and northern Lake Counties) are likely to remain dry but colder on Wednesday morning. This will bring a potential for temperatures in the lower teens to northern Klamath and northern Lake counties and low temperatures in the upper 20s or lower 30s to valleys in Douglas and Coos Counties. The National Blend of Models shows a 70% chance of temperatures at or below freezing in the lower Umpqua Basin and Coquille Valley. Additionally, there is a 30% chance of freezing temperatures along the Coos and Douglas coast. On Thursday, models continue show good agreement with a shortwave ridge of high pressure building into the area and have trended weaker with a front moving over the ridge. So expect dry weather on Thursday along with cold morning temperatures and mild to cool daytime highs. Morning lows are expected in the 10 to 20 range east of the Cascades, in the 20s for valleys west of the Cascades. Coastal areas are likely to see lows in the mid 30s with a potential for frost. Friday night into Saturday, an upper trough and frontal system approach from the northwest then move into the region. This will bring rain and snow over the area, Another stronger front, is forecast to move into the area late Sunday into Monday morning with rain, snow and gusty winds. Models are showing snow levels ranging from 3500-5000 feet as precipitation spreads into the area with these fronts. So the highest chance for snow impacts will be over the higher mountain passes. && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Winter Storm Warning until 4 PM PST this afternoon for ORZ029>031. Winter Storm Warning until 4 PM PST this afternoon above 1500 feet for ORZ023. Winter Weather Advisory until 10 AM PST this morning above 500 feet for ORZ023. Winter Storm Warning until 4 PM PST this afternoon above 3000 feet for ORZ024-026. Winter Storm Warning until 4 PM PST this afternoon for ORZ025- 027. Winter Storm Warning until 4 PM PST this afternoon above 3500 feet for ORZ028. Winter Weather Advisory until 4 PM PST this afternoon for ORZ029>031. CA...Winter Storm Warning until 4 PM PST this afternoon above 3500 feet for CAZ080-081. Winter Storm Warning until 4 PM PST this afternoon above 3000 feet for CAZ082. Winter Storm Warning until 4 PM PST this afternoon above 3500 feet for CAZ083. Winter Storm Warning until 4 PM PST this afternoon for CAZ085. PACIFIC COASTAL WATERS...Small Craft Advisory from 7 PM this evening to 10 PM PST Wednesday for PZZ350-356-370-376. && $$