Area Forecast Discussion
Issued by NWS Medford, OR
Issued by NWS Medford, OR
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930 FXUS66 KMFR 281554 AFDMFR Area Forecast Discussion National Weather Service Medford OR 854 AM PDT Sun Apr 28 2024 .DISCUSSION...Radar imagery is showing a few showers moving across southern Oregon. One of the showers produced some sprinkles just enough to make the ground wet at the office, but not measure in the ASOS. These showers are very light. Satellite imagery is showing mainly clear skies mainly east of the Cascades and south of the Douglas, Jackson, and Josephine County border. The general picture of the forecast remains in tact, so no updates are needed. Will continue to evaluate any concerns for tonight into early next week. For more information on the forecast, please read the previous discussion below. -Schaaf && .MARINE...Updated 845 AM Sunday, April 28, 2024...Weak high pressure southwest of the waters will result in light to moderate west winds and calmer seas today. A front will move through the waters late tonight into Monday with stronger west winds and possibly low end small craft conditions. The pattern will remain active Tuesday with a steep northwest swell of 8-12 feet moving into the waters. This will persist into Tuesday evening, then subside overnight. Calmer conditions are expected by mid week and could last into the end of the week with light to moderate winds. -Petrucelli/Spilde && .PREV DISCUSSION... /Issued 432 AM PDT Sun Apr 28 2024/ DISCUSSION...Satellite imagery this morning shows some scattered cloud cover west of the Cascades with some cirrus streaming over the region. Radar shows some light showers along the coast, into the Umpqua Basin, along the Cascades north of Lake of the Woods and into the Douglas County Foothills. These showers are generally light with only a few hundreths being reported at observation sites. Onshore flow will maintain a 30-60% chance of showers north and west of the Umpqua Divide today, with PoPs diminishing quickly south and east of there. It looks like a mainly dry, at least partly sunny day elsewhere (including here in the Rogue Valley) with gusty breezes (25-35 mph) developing in the afternoon. An upper trough will swing through Monday morning and this will bring a shot of showers (60-90% chance) to the coast eastward to the Cascades. We can`t rule out a shower or two around the Rogue Valley/Medford area Monday, but most of the time should be rain free. Snow levels will drop to as low as 3000 feet by Monday morning, but any snow accumulations will be confined to the mountains generally above 4500 feet. Highest amounts will be from about Crater Lake northward, where 2-5" could accumulate. Up to an inch of snow is possible over Highway 140 near Lake of the Woods with a skiff also possible on parts of Highway 97 north of Chiloquin. So, if traveling early Monday morning, be aware of the potential for some slick spots in those areas. South of the OR/CA border, we don`t think much precipitation will make it over the mountains and it will just be partly cloudy. As such, it`ll be cold first thing Monday morning with some frost in the lower Klamath, Scott and Shasta valleys. This system exits to the east Monday evening, so shower chances diminish, but it will be followed by another upper disturbance that will swing through northern Oregon Tuesday and into Idaho Tuesday night into Wednesday. Once again, we`ll be on the southern fringes of this system, so PoPs (for showers) remain highest across the north, lowest across the south. Snow levels bottom out near 2500 feet Tuesday morning, but again most, if not all, snow accumulation will be in the mountains north of Crater Lake. Overall, temperatures will remain near to below normal. Frost/freezing conditions west of the Cascades are becoming more likely given the main area of precip potential is north of the Umpqua Divide. Frost (lows 33-36F) chances (50-80% chance) are highest for a few hours in the typically colder locations (Illinois/Applegate Valley/Grants Pass areas) both Tue/Wed mornings. Freezing conditions (<=32F) are possible (20-30% chance) in the Illinois Valley as well, but much will depend on how much cloud cover lingers during the overnight hours. Clearing looks more widespread Tuesday night/Wednesday morning, providing a better chance for frost/freeze for the Illinois/Applegate Valley and Grants Pass areas. As the upper trough shifts to the east, things dry out on Wednesday with some sunshine and a slightly milder afternoon (high temps back closer to seasonal normals). Models maintain some degree of uncertainty after Wednesday with NBM still showing some PoPs (20- 30%) across NW portions of the CWA. This stems from a smaller percentage of model members (GEFS/Canadian and to an even lesser extent ECENS) showing a flat upper ridge and a weak trough, you guessed it, skimming over the top Wednesday night into Thursday. More plausible scenarios feature a bit stronger ridge and no precip along with a more significant warm up. We`ll see how it shakes out, but it does appear that temperatures should rebound to above normal levels Thu/Fri. Models are showing a potentially more substantial trough moving in next weekend, but confidence in the details is low at this point. -Spilde/BR-y AVIATION...28/12Z TAFs...Along the coast and just offshore, MVFR ceilings will be the predominate condition through the TAF period. The exception will be at North Bend where ceilings should improve to VFR in the afternoon. Also visibilities could be reduced at times through 18z. Inland, VFR conditions will continue through the TAF period, however the higher terrain will be occasionally obscured until 0z, along and west of the Cascades and Siskiyous. West to northwest winds will increase early this afternoon east of the Cascades including Klamath Falls with gust up to 20 kts possible. -Petrucelli && .MFR WATCHES/WARNINGS/ADVISORIES... OR...None. CA...None. PACIFIC COASTAL WATERS...None. && $$