Area Forecast Discussion
Issued by NWS Medford, OR
Issued by NWS Medford, OR
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362 FXUS66 KMFR 160451 AFDMFR Area Forecast Discussion National Weather Service Medford OR 951 PM PDT Sat Jun 15 2024 .UPDATE...Updated the aviation and marine sections. && .AVIATION...16/06Z TAFs...VFR is expected to remain the predominant condition through Sunday evening. But, patches of stratus are expected along northerly facing slopes, including the Umpqua Divide, late tonight into early Sunday morning. The next front will move across the area Sunday afternoon through Sunday night with skies becoming cloudy and a slight chance to chance of showers, mainly in Oregon. -DW && .MARINE...Updated 830 PM Saturday, June 15, 2024...North winds with a weak thermal trough will peak late this evening, building steep seas south of Port Orford that will persist into Sunday morning. Relatively low, short period seas are expected later Sunday into Sunday evening. Then, north winds strengthen late Sunday night with steep seas expected south of Port Orford again, at least into Tuesday morning, and possibly for much of the week. The week will be filled with persistent north winds over the coastal waters. Areas north of Cape Blanco are looking at north winds of 10 to 20 knots while south of Cape Blanco is looking at 15 to 25 knots. Overall seas are expected to remain under 10 feet but areas south of Port Orford is likely to see some steep wind driven wave action at times due to the north winds approaching 25 knots. -Sargeant/DW && .PREV DISCUSSION... /Issued 236 PM PDT Sat Jun 15 2024/ SHORT TERM...Through Tuesday morning...Scattered cloud cover remains from a low pressure system passing to the north this morning. While this system was mostly as unimpactful as expected, the Roseburg Airport had 0.20 inches of rainfall today. Meanwhile, a rain gauge about 3 miles west of the airport got 0.02 inches while another gauge 3 miles to the east got 0.05 inches. A cold air mass associated with the low pressure system will remain over the area tonight, bringing below seasonal low temperatures across the area. A Freeze Warning remains in place for Sunday from 1 AM to 8 AM for areas east of the Cascades for areas that will drop to 32 degrees or below. Areas covered by this Watch include eastern Klamath County, most of Lake County (Summer Lake and Adel are forecast to be 3 to 4 degrees too warm), as well as parts of Modoc and northeast Siskiyou County. Other areas east of the Cascades will still see chilly temperatures, even if they don`t quite reach freezing level. Sensitive plants and animals may require some planning overnight. The low pressure system will move away to the northeast during the day Sunday, but a cutoff low will develop in its wake. That cutoff will swing over east side areas, bringing slight (10-30%) precipitation chances. Most of the measurable rainfall is expected over Lake County, but some of those lower 10-15% chances are over Klamath County as well as Mount Ashland and Mount Shasta. Amounts are forecast to be light, with 0.15 inches possible over higher elevation terrain in Lake County and less in other areas. Gusty evening winds will cover wider areas east of the Cascades than normal, but nothing approaches Advisory levels. Sunday night will be chilly again as the cold air mass remains in place. A Freeze Watch is in place for areas east of the Cascades from late Sunday into early Monday morning, this time including more areas of Modoc County. An upgrade to a Freeze Warning is likely, but additional guidance will help to determine the best area for the final product. Probabilistic NBM guidance had 20-50% chances of freezing temperatures in Modoc and eastern Lake counties, which isn`t generally enough confidence for a Warning this far out. The absence or presence of cloud cover during the day could further change expected nightime temperatures in this period. With both the main and cutoff low off to the east, Monday will be a transition from active to likely stable atmospheric conditions. While west side valleys will warm up a few degrees from Sunday`s daytime highs, temperatures across the area will remain below seasonal norms. Monday night into Tuesday will remain cooler as well, but the current forecast has a greatly reduced area of freezing concerns. Forecast overnight temperatures of 32 degrees or below are currently limited to the Chemult, Crescent, and Fort Rock areas for Monday night into Tuesday morning. -TAD LONG TERM...Tuesday through Saturday night. Gusty breezes and cool temperatures continue Tuesday. But, the spring-like weather will then come to an abrupt end. The outlook is for a warming trend with dry and much warmer/hot weather inland for the rest of the week. Meantime, northerly winds will result in persistent night and morning coastal low clouds and patchy fog. With that said, there are some minor model differences in the strength of ridging that will affect the extent of heating, and more importantly will make the difference between a stable air mass or a weakly unstable air mass that would allow the introduction of modest, slight chances of afternoon/evening thunderstorms over some portion of the area. For now, the forecast reflects the large majority of ensemble members, supporting a persistently stable air mass. -DW && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Freeze Warning from 1 AM to 8 AM PDT Sunday for ORZ029>031. Freeze Watch from late Sunday night through Monday morning for ORZ029>031. CA...Freeze Warning from 1 AM to 8 AM PDT Sunday for CAZ084-085. Freeze Watch from late Sunday night through Monday morning for CAZ084-085. PACIFIC COASTAL WATERS...Small Craft Advisory from 11 PM Sunday to 5 AM PDT Tuesday for PZZ356-376. Small Craft Advisory until 8 AM PDT Sunday for PZZ356-376. && $$