Area Forecast Discussion
Issued by NWS Medford, OR
Issued by NWS Medford, OR
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534 FXUS66 KMFR 300315 AFDMFR Area Forecast Discussion National Weather Service Medford OR 815 PM PDT Wed May 29 2024 .DISCUSSION... Pretty quiet weather persists this evening with no thunderstorms around like the last few evenings. There are some prescribed burns which are putting some smoke out east of the Cascades. Therefore, we added patchy smoke wording in northern Lake and Klamath Counties due to the smoke on satellite. Very few people should be impacted from this smoke. Otherwise, temperatures will be warm enough tonight to avoid the threat from frost and freeze west of the Cascades. East of the Cascades, most areas will see frost with some spots dropping below freezing, like Chemult. Read the discussion for more information on the wet period next week. && .AVIATION...30/00Z TAFs...Along the coast VFR conditions continue this evening and overnight with a less than 10% probability of ceilings falling below 3,000 feet. Northerly winds will pick up again tomorrow. There is a 60-70% probability for winds to gust to 22 knots between 3 PM-6 PM Thursday. Inland, west of the Cascades, ceilings are expected to remain VFR through the TAF period. Winds will be slightly breezy Thursday afternoon, and some locations could see wind gusts reaching 20-25 knots at most. East of the Cascades, VFR conditions will continue through the TAF period. Moderate winds with peak gusts nearing 25 kts at Klamath Falls this afternoon will wind down this evening. -Miles/Hermansen && .MARINE...Updated 800 PM Wednesday, May 29, 2024...A thermal trough is developing this evening and tonight, resulting in increasing north winds that will reach Small Craft Advisory conditions for all south of Bandon. The thermal trough will strengthen further, peaking Thursday evening, and persisting through at least Friday evening; resulting in gale force winds for most areas south of Cape Blanco and for isolated instances across the waters between Bandon and Cape Blanco. Meanwhile small craft conditions will expand north over the rest of the waters that will last into at least Friday evening. The thermal trough will weaken overnight Friday into Saturday and north winds will diminish as an upper trough approaches. Calmer seas are expected by the weekend and into early next week after the wind waves have diminished. -Miles/Hermansen && .PREV DISCUSSION... /Issued 216 PM PDT Wed May 29 2024/ SHORT TERM...Rest of today through late Thursday night...At the large scale, a midlevel trough is gradually moving off to the east today as a low amplitude ridge builds in behind it. At the moment, this has resulted in NW flow aloft in the local area as we`re sandwiched between the two regimes, which has resulted in cooler (relatively) temperatures and a little bit of cloud cover. Per satellite imagery, cirrus is moving southeast across the region, while some scattered cumulus is present in Douglas/Coos and NW Curry/Josephine/Jackson counties this afternoon. Overnight, temperatures will drop to levels similar to last night/early this morning, if not a tad lower due to increased radiational cooling with relatively less cloud cover. Tomorrow will then see clearer, warmer weather with afternoon temperatures in the high 70s to low 80s (western valleys and the Brookings area), low to mid 70s (eastern valleys), and low to mid 60s (mountains, remainder of the coast). We`ll have some seasonable afternoon/evening breezes and dry weather through the entire region. A little bit of cloud cover is expected in the morning (stratus in Coos into inland Douglas counties as well as some more upper level cirrus) that will clear over the course of the day. Overnight temperatures will then be average for this time of year, a couple of degrees warmer than tonight`s temperatures. Finally, this will be my last AFD here at Medford, as this forecaster is transferring to southern CA (please keep your boos and hisses for after the AFD, please). Not very interesting weather as a send off, but lovely conditions to move in, at least. Thanks for everything Medford, I`ll miss you. -CSP LONG TERM (Friday through Tuesday)... Overview: The long term will be noted by slightly above normal temperatures and generally dry conditions until Sunday night/Monday. The system coming into the region end of the weekend/early next week will be moisture rich but lacking some variables which could make this more impactful. We will talk about this further below, but at this time it does appear impacts will be limited at best. The coast could see rainfall amounts approaching 2 inches in some isolated areas that could cause minor nuisance issues. Interestingly enough, the rainfall amounts have gone up each forecast over the last 24 hours, so we could see changes to those amounts near the coast. Otherwise, little to no impacts are expected inland as amounts drop off significantly, and we are not expecting thunderstorms at this time. Lastly, we will have several breezy days in the forecast, and Monday looks to be the "windiest" of the days at this time (behind the cold front), especially the eastside across our typical windy spots where a wind advisory may come to fruition. Further Details: By Friday, it looks like the upper levels might resemble a general zonal (west to east) type of flow downstream of the next trough. There is a small discernible piece of energy embedded in this flow, so expecting clouds to increase in coverage Friday and more so on Saturday. By Sunday, appreciable upper level moisture will be present with forecast soundings suggesting PWATs could be around 1.50" at KOTH with a very deep saturated column. This moisture will coincide with a strong H3 jet nosing into the area. The left exit region of the upper jet, and the 500mb vorticity max are both a little farther north than one would like to see for high rainfall rates. We will have to watch these variables because they will coincide with the highest rainfall amounts if phased together correctly, and at this time it does look like those amounts may be highest just to our north along the central to northern Oregon coast. Along our coastal waters of southern Oregon, the probability for rainfall amounts to be 0.50" or more in 12 hours is around 30-40 percent ending Monday morning. This is of course a broad brush with coarse resolution given this is Day 5/6. Total forecast rainfall amounts currently put much of Curry County at 1.00-1.50" of rainfall over 36 hours from early Sunday afternoon through Monday night. The highest rates could be between Sunday night and Monday morning, so the Monday morning commute may have nuisance issues with rainfall. All that said, its the coast and it can inherently take a lot of rainfall, so at this time we are expecting very limited impacts, but it may not be a bad idea to plan for longer commutes on Monday morning if you live along/near the coast. -Guerrero && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT Thursday for PZZ350-356-370-376. Gale Warning from 5 AM Thursday to 11 PM PDT Friday for PZZ356- 376. && $$