FXUS66 KMFR 261202 AFDMFR Area Forecast Discussion National Weather Service Medford OR 502 AM PDT Mon Aug 26 2024 .UPDATED Aviation Discussion... && .AVIATION...26/12Z TAFS...Patchy LIFR to IFR low clouds and fog is expected through around 18Z this morning, including at North Bends. Low clouds and fog will clear to VFR in the late morning around 17- 19z. Then expect area of IFR and MVFR ceilings to return to the coast, mainly from Cape Blanco north, late this evening and tonight. Elsewhere, across inland areas, VFR will persist through Monday night under clear to mostly clear skies with light winds. -CC && .PREV DISCUSSION... /Issued 307 AM PDT Mon Aug 26 2024/ SHORT TERM... Today will be a fairly quiet late summer day with near normal temperatures, plenty of clear skies and fairly normal north west breezes. Conditions become more active heading into Tuesday with an upper level wave moving into the Pacific northwest and a dry cold front sliding through Oregon. There is plenty of guidance showing an uptick in wind speeds on Tuesday afternoon. The strongest winds will be located in the northern portions of our forecast area with a low chance of wind gusts hitting 30 mph. This cold front isn't particularly strong on the other hand with temperatures only trending a few degrees lower compared to what we'll observe for highs today. With the passage of the upper level trough, high pressure will start to build into north eastern Oregon on Tuesday evening and the lower sections of the atmosphere really begin to dry out. In addition, a thermal trough will develop over the westside valleys around mid day Wednesday. Temperatures trend slightly warmer, and the thermal trough should really warm up the southern Oregon coast. MOS guidance is forecasting highs between 84 to 86 for Brookings Oregon on Wednesday afternoon. -Smith LONG TERM... Starting Thursday morning, the thermal trough still remains in place west of the Cascades and is clearly visible looking at 1000-500 mb thickness' and the 850 mb heights. The light east flow over the Cascades will persist with 500 mb heights increasing into Thursday afternoon. The end result here is temperatures pushing into the upper 90's and perhaps the lower 100's. These thermal troughs have a habit of being warmer and lasting a bit longer than guidance anticipates. Look for a little heat to end August with temperatures 10 degrees warmer than their normals for this time of year. Heat risk is still low as our overnight lows cool off into the lower 60's. Only people very susceptible to heat illness are at risk on Thursday and Friday. Guidance is then showing an upper level low approach the California coastline on Saturday afternoon. The NBM is suggesting a low 15% chance of precipitation east of the Cascades and the thunder probabilities are a little lower than that. This seems pretty reasonable based on where the low is Saturday evening. Furthermore, there isn't much CAPE and the bases of the storms appear to be pretty high based on GFS forecast soundings near Klamath Falls. More often than not, these environments end up producing a few radar echos with just a handful of cloud to ground flashes. Sunday evening is looking better as ensemble guidance is placing the low much closer to the coast and some models appear to bring the low a bit farther inland. With better forcing, a little more moisture and better lift, thunderstorm and precipitation probabilities should be on the increase Sunday afternoon and evening. Again east of the Cascades is the main area of concern, although an elevated storm west of the Cascades is not out of question. -Smith MARINE...Updated 200 AM Monday, August 26, 2024...North winds will gradually increase, strongest south of Cape Blanco, with conditions approaching advisory strength late this afternoon. Advisory strength winds and seas will develop Monday night into Tuesday morning. North winds are likely to reach gales on Tuesday afternoon through Wednesday night, with very steep and hazardous seas south of Cape Blanco and beyond 2 nm from shore. Gradual improvement is expected Thursday, with conditions likely remaining hazardous to small craft. -CC FIRE WEATHER.../Issued 200 PM PDT Sun Aug 25 2024/ Much like the last few nights/early mornings, the latest satellite image shows marine stratus along the coast and inland into the coastal river valleys and Coquille Basin. The inland push of the marine stratus has been slow but steady and could move into portions of the Umpqua Basin towards daybreak. Elsewhere skies are clear. The latest water vapor image shows a weak upper low weak upper low near 38N and 139W. The upper low will move inland in northern Cal early this afternoon and it will become negatively tilted late in the afternoon. This along with increasing instability could set the table for isolated thunderstorms east of the Cascades this afternoon into early this evening. The wildcard in terms of thunderstorm coverage or lack thereof will be the extent of the smoke. If the smoke remain extensive, it will put a cap or even result in less instability resulting in a couple of isolated storms or nothing at all. Weak troughing remains over the area for the rest of the week. While most locations will be dry, we cannot rule out a slight chance of afternoon and early evening thunderstorms Wednesday and Thursday east of the Cascades. Afternoon temperatures during this time will be slightly below normal. Friday through this weekend. All of the data remains locked in with a common solution. The clusters still point to the upper low deepening with the center of the upper low just west of the forecast area. The ensemble means and operational models also in good agreement with the placement of the low/trough with it centered slightly to the west. Afternoon temperatures Friday through the weekend for the interior are likely to end up below normal (6-8 degrees) for this time of the year. While precipitation cannot be ruled out, the best chance is expected be east of the Cascades and mainly during the afternoon and early evening hours Friday, and Saturday, with marginal instability, moisture and trigger. Sunday the low is still offshore, but the mid levels are dry and there is little or no trigger, so the threat for storms are low. -Petrucelli && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory from 8 AM Tuesday to 8 PM PDT Wednesday for PZZ350-370. Small Craft Advisory from 11 PM this evening to 8 PM PDT Wednesday for PZZ356. Gale Watch from Tuesday afternoon through Wednesday evening for PZZ356-376. Small Craft Advisory from 11 PM this evening to 3 PM PDT Tuesday for PZZ376. && $$ CC/CC/CC