Area Forecast Discussion
Issued by NWS Medford, OR
Issued by NWS Medford, OR
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247 FXUS66 KMFR 282147 AFDMFR Area Forecast Discussion National Weather Service Medford OR 247 PM PDT Fri Jun 28 2024 .DISCUSSION...Clear skies continue over northern California and southern Oregon this afternoon, with the slightest hints of terrain- influenced cumulus flickering on satellite imagery. A weak trough will pass over the area through the weekend, helping to keep daytime temperatures near seasonal levels on Saturday and Sunday. This pattern will continue to push marine moisture over the Oregon coast in the mornings. This layer could move into the Umpqua Valley on Sunday morning. However, no precipitation is expected under these clouds. The weekend trough trough will also bring evening chances for active weather east of the Cascades. Model soundings showing CAPE values between 100 and 200 J/Kg on Saturday evening as well as upper level vorticity and above average moisture. These conditions will make evening thunderstorms a possibility around the northern Klamath/Lake County border on Saturday evening. These chances are slight, currently topping out at 10% in a small area, but the chances have been increasing by a percentage or two daily. Thunderstorm chances are looking higher for Sunday evening, reaching 10-15% in eastern Lake and Modoc counties. Less moisture will be present but CAPE values could be in the 300-400 J/Kg range which is more than enough to trigger thunderstorms in this area. A pattern change to upper level ridging will build next week and could remain. This period is particularly important, as this upper level stability will drive conditions on the 4th of July. Ridging looks to build through the week, with the highest temperatures and the driest air present on July 4th, 5th, and 6th. Temperatures in the Rogue and Shasta valleys as well as in western Siskiyou valleys have a 50% of exceeding 100 degrees in this period. Other west side valleys and areas east of the Cascades look to be in the low to mid 90s under the ridging pattern. Exceptionally low relative humidity values are expected in all inland areas. With gusty afternoon winds continuing, fire hazards for next week will be substantial. Activities that could create sparks or flames should be avoided, as fuels will be dry and winds will easily carry sparks or embers to new areas. Some details will require additional guidance. Forecast temperatures for Brookings may increase as next week`s pattern comes into better focus, as periods of Chetco Effect winds are possible. Additionally, Heat Risk values increase through the week. Areas of Advisory-level conditions possible in the Rogue, Shasta, Scott, and western Siskiyou valleys possible by the end of the week. Finally, the NBM temperature guidance does show a 8-12 degree interquartile range for daytime highs, suggesting some uncertainty in the timing of how ridging will build. So hot and dry is expected, but please check back as the finer points come into focus. -TAD && Today, we bid farewell to Ryan Sandler, our Warning Coordination Meteorologist, as he begins his much anticipated and well-deserved retirement. Ryan began his career at Neena, WI in December of 1989, before moving on to Milwaukee, WI, then Wilmington OH, and finally here to Medford in 1998. Ryan has been a knowledgeable and respected colleague, a dedicated public servant, and an all-around great friend to those of us here at the Medford forecast office these past many years. We wish you fair winds, fifty-five degree temperatures, and following seas as you embark on this next journey. Go Sox! && .AVIATION 28/18Z TAFS...The only clouds on satellite are some lower cu along the coastal range this afternoon. VFR conditions are anticipated through the remainder of the day. More lower ceilings will likely build into the coast tonight, although the inversion doesn`t appear as strong as the last few nights. Periods of LIFR ceilings remain possible over North Bend and sections of the coast with clearer conditions farther inland. -Smith && .MARINE...Updated 230 PM Friday, June 28, 2024...Gusty winds will pick up later this afternoon into the early evening, especially south of Gold Beach. Look for steep wind driven seas with wave heights peaking around 8 feet or so. These conditions will remain hazardous to smaller crafts through Friday night. Winds and seas lower Saturday afternoon into Sunday for most of the area. However, areas from Pistol River south within about 15 NM of shore could observe brief and isolated advisory level seas as winds peak in the afternoon, generating a steep wind wave. These conditions will likely be too short lived and localized to warrant needing a warning, but you`ll want to watch Buoy 27 to monitor conditions in this area to be safe before heading out. Then, a very strong thermal trough is expected to develop next week beginning on Monday and lingering towards the end of the week. The peak should be either Tuesday or Wednesday evening, but there is some spread in the forecast and uncertainty here. As for the wind speeds expected during the peak of the thermal trough, the chance for gale force wind gusts south of Cape Blanco is 70% or greater (90% plus south of Pistol River) and this will drive very steep waves. There is also a moderate (20-40%) chance that gale force winds develop over the waters north of Cape Blanco. -Miles/Smith && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT Saturday for PZZ356-376. && $$ TAD/BPN/CZS