


Area Forecast Discussion
Issued by NWS Medford, OR
Issued by NWS Medford, OR
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991 FXUS66 KMFR 232342 AFDMFR Area Forecast Discussion National Weather Service Medford OR 442 PM PDT Mon Jun 23 2025 ...Updated AVIATION discussion for 00Z TAFs... .DISCUSSION...Weak ridging overhead has brought mostly clear skies and warmer temperatures to the area today. A weak trough, illustrated by extensive clouds offshore, will dig into the area this evening and tonight, with little effect other than providing support for a decent marine layer push overnight and into the morning. We do expect stratus and fog to push into the coast and the coastal valleys by sunrise tomorrow morning, and some clouds could make it all the way to Roseburg. Much like today, any marine layer cloudiness will quickly burn back offshore through the morning. Temperatures on Tuesday will warm by about 5 degrees over those of today, then we will begin to cool off a bit through the rest of the work week as weak, but broad troughing sets up over the region. While the forecast will remain dry, for the most part, and temperatures are expected to stay around normal for this time of year, daily marine layer pushes will continue at the coast and coastal valleys, and at times may push into the Umpqua Basin, or even portions of the Rogue and Illinois valleys. The strongest push will likely be Wednesday and/or Thursday morning, due to the overhead trough allowing for a thicker marine layer that would more easily pass over some of the area mountains. The trough axis will pass overhead Wednesday afternoon, and some models, namely the NAM, are suggesting the possibility of convection in the Mount Shasta/Medicine Lake area. It does not appear that atmospheric moisture will be sufficient enough for any significant convective development, and the NAM is known to overdue it in situations like this. We will keep an eye on it nonetheless, just in case, but most likely, we will only see cumulus fields develop across the area in the afternoon. Near normal temperatures and dry conditions then continue for the remainder of the workweek as broad troughing remains in the area, and we should see daily marine pushes along the coast. Heading into the weekend, ridging finally begins to nudge into the region, and the thermal trough is expected to redevelop along our southern coast. As a result, temperatures will see a quick warm up through Saturday and Sunday and into early next week, with highs rising about 10 to 15 degrees above normal for late June. Ensemble suites are starting to show a potentially interesting pattern developing early next week. With the ridge passing just to our east and strengthening as it moves over the Rockies, a trough develops off the coast of California, which then attempts to move onshore around Monday, and according to some models, takes on a negative tilt as it does so. This would allow the area to tap into monsoonal moisture from the south, and is a prime pattern for thunderstorms in our forecast area. Have left mention of rain or thunderstorms out of the forecast for now, mainly due to being a week out and with low confidence, but will reassess the situation over the next few forecast cycles. Lastly, it is worth noting that while outside of the typical forecast period of concern, the majority of ensemble members across all suites are showing another deep trough somewhere over the West Coast middle/late next week (including Independence Day), in a pattern similar to the cool and showery pattern we experienced here over the last few days. -BPN && .AVIATION...24/00Z TAFs...VFR levels are present across northern California and southern Oregon, with high clouds moving over areas west of the Cascades and normal diurnal wind changes. A marine layer looks to return to the coast this evening, bringing IFR or LIFR conditions to North Bend. This layer currently looks to persist through most (if not all) of the TAF period as guidance is currently divided on the chances of clearing on Tuesday afternoon. -TAD && .MARINE...Updated 430 PM Monday, June 23, 2025...A thermal trough is bringing gusty north winds, building steep seas south of Cape Blanco through Tuesday morning. Winds and seas are expected to improve Tuesday afternoon and remain below advisory through the middle of the week. A thermal trough could develop near the end of the week and persist into the weekend, bringing steep wind-driven seas to all areas over the weekend. -Hermansen/TAD && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 11 AM PDT Tuesday for PZZ356-376. && $$