Area Forecast Discussion
Issued by NWS Medford, OR
Issued by NWS Medford, OR
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156 FXUS66 KMFR 202350 AFDMFR Area Forecast Discussion National Weather Service Medford OR 450 PM PDT Fri Sep 20 2024 Updated AVIATION Section .DISCUSSION...There are no major changes to the 7-day forecast this afternoon, with quiet, mainly seasonable conditions of cool to cold nights and warm to very warm afternoons. The items of most signficant note are: breezy easterly winds over the Coastal Range in Curry and western Josephine County into Monday with downslope warming for Brookings, and a warming trend inland Saturday into Tuesday with readings by Tuesday expected to be well above normal (by about 10 degrees) but still generally several degrees below the vicinity of record highs. Conditions for the remainder of the coast will be near normal. This is due to a pattern of high pressure centered offshore and a trough in the Great Basin with a thermal trough near the coast. This pattern will strengthen as the ridge builds into our region and a trough develops over the southern California coast during the weekend into early next week. The pattern looks to change on Wednesday as a trough in the Gulf of Alaska approaches the west coast and kicks the ridge inland. There is uncertainty in the strength of the trough, but it is highly likely that the bulk of precipitation will be focused north of our area, with the highest probability in our area for western Douglas and Coos counties late Wednesday into Wednesday night, and a low/minimal probability of precipitation for south central Oregon and northern California. Another similar or weaker trough is expected around Thursday night into Friday with a higher probability that rain will be strictly limited to the coast, Douglas County, and northward. Besides the risk of rainfall, the cloud cover and onshore flow pattern will bring cooling for the second half of next week. && .AVIATION...21/00Z TAFS...VFR will prevail area wide through the next 24 hours due to low-level offshore winds west of the Cascades and a drying air mass. Patchy shallow fog is possible in the deeper valleys after midnight tonight through sunrise Satuday, but will dissipate during Saturday morning. Gusty north winds (~30kt) are expected this evening at North Bend and again Saturday afternoon/evening. -Spilde && .MARINE...Updated 200 PM Friday, September 20, 2024...A thermal trough and associated pressure gradient along/near the coast will remain in place through early next week; as a result, strong northerly winds are expected through the afternoon and evening hours, especially south of Port Orford where very steep seas and occasional gale gusts are possible. Elsewhere, steep seas and advisory strength northerly winds are expected north of Port Orford through tomorrow. We are going to need an extension of the Small Craft Advisory beyond Saturday night, but will reassess this after the current hazards play out. Main reason for this is because observations are suggesting wind speeds might be forecast on the high side, so trended forecast wind speeds slightly lower over the next 24-48 hours. If this trend holds, then a Small Craft Advisory can be extended into early next week. However, there is a scenario where the wind speeds are in fact going to remain strong and perhaps stronger than the updated forecast, so we may need to consider a Hazard Seas or Gale Warning. It will serve us well to wait another shift or so to analyze the situation better, mainly conditions south of Port Orford where the stronger winds are forecast. The thermal trough is forecast to move inland with weakening winds and easing seas late Tuesday into Wednesday. This will result in relatively calm seas and light wind speeds through at least Friday. -Guerrero && .FIRE WEATHER...Issued 200 PM Friday September 20, 2024...A rather quiet weather pattern is in store for the next 10 days. Dry weather will continue through at least next Tuesday. Afternoon temperatures will trend upward during this time with the warmest days Monday and Tuesday as the upper ridge builds over the forecast area. A thermal trough has set up along the coast and will remain a fixture into the start of next week. The net result will be gusty east to northeast breezes near and at the ridges at night into the morning hours in Fire Zones 618, 619, and 620 with moderate overnight recoveries. However due to the recent rains, fuels are just not there, so there is little or no concern for critical conditions. Looking at some ensemble data and comparing to the climatology to this time of year, nothing jumps out as extreme. There`s good agreement that an upper trough will push into the area Wednesday morning along with a surface front which could bring light precipitation to the northwest part of Fire Zone 616 and most of 615 Wednesday afternoon and evening, then drying out Wednesday night into Thursday. Another front will brush by the northwest part of the area late Thursday night into Friday morning, with the net result being similar to Wednesday`s front. Afternoon temperatures Wednesday, Thursday and Friday next week will trend lower and end up being near normal for this time of the year for the interior. -Petrucelli && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT Saturday for PZZ350-356-370-376. Hazardous Seas Warning until 11 PM PDT Saturday for PZZ356-376. && $$