Area Forecast Discussion
Issued by NWS Medford, OR
Issued by NWS Medford, OR
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193 FXUS66 KMFR 142345 AFDMFR Area Forecast Discussion National Weather Service Medford OR 445 PM PDT Tue May 14 2024 .UPDATE...Updated the aviation section. && .AVIATION...15/00Z TAFs...VFR conditions will prevail through Wednesday evening, with a couple of exceptions. Starting around 04Z this evening, IFR ceilings are expected to return to areas north of Cape Blanco and persist into mid-morning on Wednesday. Also, patchy IFR ceilings are expected in the Umpqua Basin late tonight and could potentially affect Roseburg for a brief period early Wednesday morning (between 12z-17z). Otherwise, expect gusty winds near the coast, strongest during the afternoon and evening hours with similar strength as today during late Wednesday. /DW && .MARINE...Updated 130 PM Tuesday, May 14, 2024...A thermal trough pattern will maintain gusty north winds and very steep and hazardous wind driven seas for all areas through much of the week. Winds will be strongest, reaching gales, and seas will be steepest south of Cape Blanco and during the afternoons and evenings. North of Cape Blanco, very steep and hazardous seas with strong winds are expected, but gales are no longer expected so hazards have been updated to reflect this. The thermal trough pattern weakens some on Thursday and gales will ease. Despite this subtle improvement, gusty winds and very steep and hazardous seas will persist through the end of the week. Conditions may improve overall over the weekend as the upper level pattern transitions, though expect conditions to remain hazardous to small craft for areas south of Cape Blanco as northerly winds continue. /BR-y && .PREV DISCUSSION... /Issued 156 PM PDT Tue May 14 2024/ SHORT TERM...Tonight through Thursday...Strong high pressure aloft and at the surface is centered well off the U.S. West Coast, but will be the main player and influence on our weather for the next couple of days. Satellite imagery is showing the high clouds from this morning (and also the low clouds in the Umpqua Basin) have largely dissipated or exited the area to the south. Bright, sunny skies can be expected area wide the rest of this afternoon. Inland areas will be warm with highs generally 10-15 degrees F above normal. A strong thermal trough is currently set up along the NorCal and SW Oregon coast and this is leading to gale force winds and high seas over the marine waters. On land, NNE offshore winds originating in the coast ranges, are funneling down the Chetco River valley and resulting in significant warming due to compression. As such, temperatures early this afternoon are already in the low to mid 80s in Brookings. With more of a northerly wind component, areas farther north along the coast won`t get to experience this effect and will remain cooler with highs in the 60s (maybe low 70s for areas just a bit inland). Breezy winds inland this evening will wane with the setting sun. Expect mainly clear skies tonight, though some low clouds will develop later this evening/overnight along the coast north of Cape Blanco as north winds subside. In fact, some clouds are already showing up near Cape Arago. Wednesday`s weather will be mostly a repeat of today. Low clouds along the coast north of Cape Blanco peel back offshore during the mid-late morning; sunny skies prevail inland. Inland temperatures probably top out at least a few degrees higher than today. Another warm day is expected in Brookings as winds continue channel down the Chetco valley. A deeper marine layer is expected to develop Wednesday night, and this should result in more cloud cover/patchy fog along the coast north of Cape Blanco. The clouds could also push into portions of the Coquille Valley and the Umpqua Basin. -Spilde LONG TERM...Thursday May 16th - Tuesday May 21st...The upper level ridge that lead to the warm temperatures earlier in the week will start to flatten as a trough moves down the British Columbia coast. This will help push a thermal trough (heat low) from along the southern OR/NorCal coast inland. Typically, this leads to the warmest temperatures of a stretch inland while coastal areas, especially Brookings, cool off. The trough then slides over the northwest U.S. Friday. Any precipitation associated with this looks to remain well to our north, so dry weather will continue in the region, but the resulting cooler, northwesterly flow will result in temperatures dropping (by more than 10 degrees in some areas) Friday afternoon compared to Thursday. Breezy northwest winds at the surface will pick up in the late afternoon into the evening, but not anything overly gusty. While dry weather continues through the weekend, temperatures will cool each day under continued northwesterly flow as another shortwave trough starts to slide down from the northwest. This will gradually dig far enough south by Monday that about 10-15% of members of the National Blend of Models indicate some precipitation is possible in northern Douglas and Klamath counties. Another shortwave Tuesday will bring these chances further south and east, though model differences in the strength and timing of this system are numerous at this range. -CSP && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Gale Warning until 5 AM PDT Thursday for PZZ356-376. Hazardous Seas Warning from 5 AM Thursday to 5 AM PDT Friday for PZZ350-356-370-376. Small Craft Advisory until 5 AM PDT Friday for PZZ350-370. && $$