Area Forecast Discussion
Issued by NWS Medford, OR
Issued by NWS Medford, OR
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228 FXUS66 KMFR 111922 AFDMFR Area Forecast Discussion National Weather Service Medford OR 1222 PM PDT Thu Jul 11 2024 .DISCUSSION...Made some minor updates to sky cover for this morning to better align with satellite observations regarding the marine stratus along the coast. Away from the coast, skies are clear across the region with the exception of wildfire smoke dispersed across the area. A look at air quality sensors shows mainly good air quality for most locations, with degraded air quality focused in the vicinity of the Salt Creek and Shelly fires. Overall, conditions will be very similar to those of yesterday as above normal temperatures continue. Various heat products remain in effect for most areas away from the coast and south of the Rogue-Umpqua Divide, and details can be found at NPWMFR. Today`s efforts will focus on the upcoming thunderstorm threat east of the Cascades as well as gusty breezes through the weekend. For more details on current thinking regarding the upcoming pattern, see the previous discussion below. /BR-y && .AVIATION...11/18Z TAFS...VFR ceilings will prevail for the TAF period except for locations closer to the coast as lowering ceilings will move in again this evening. These ceilings will probably bounce between 1000 to 500 feet for most of the night. Smoke from active fires will reduce visibility over small areas through this afternoon. The Shelly fire in western Siskiyou County is burning with the most intensity, so prepare for lower visibility over sections of western Siskiyou County. -Smith && .MARINE...Updated 830 AM Thursday, July 11, 2024...A thermal trough will continue to bring moderate to strong north winds to all waters through the end of this week into at least the first part of this weekend. Gale force winds are expected at times south of Cape Blanco along with very steep, hazardous seas. Peak winds and seas are expected this evening and again Friday evening. Elevated winds and seas continue Saturday and gradually ease on Sunday, but some amount of disturbed seas will persist into next week. -Spilde && .FIRE WEATHER...Issued 400 AM Thursday July 11, 2024... ..Fire Weather Watch for Gusty Wind and Low RH for portions of Oregon Fire Zone 624 and California Fire Zone 285 for Friday afternoon and evening... ..Near critical fire weather conditions possible through at least this weekend... Hot, breezy, low humidities, and occasional unstable afternoon conditions will persist through this weekend, and this will lead to near critical fire weather conditions. Additionally, we have a chance for thunderstorms this weekend, mainly across the eastside. Single digit RH values are also forecast this week during the afternoon hours across the eastside and some isolated westside valleys in Northern California. While winds today will be breezy with gusts 15 to 20 mph; conditions look to worsen on Friday. Statistical and ensemble guidance is showing gusts 25 to 30 mph for several locations in the Fremont-Winema National Forest as well as the Modoc National Forest with the sustained critical humidities. Will be issuing a fire weather watch as confidence is beginning to grow there. Portions of fire zones 280 and 282 also look to reach criteria, and would like to coordinate with the Incident Meteorologist of the Shelly Fire before issuing anything for those zones. For the thunderstorm potential, it should be noted that the trend stayed the same from yesterday to this morning for both Saturday and Sunday. We were seeing slight increases early in the week, but those trends have flatlined. A lot will depend on how a ridge of high pressure sets up over the Four Corners region as this will direct monsoonal moisture northward. There is about a 10-20 percent chance for isolated thunderstorms both Saturday and Sunday. -Schaaf/Guerrero && .PREV DISCUSSION... /Issued 409 AM PDT Thu Jul 11 2024/ DISCUSSION...Satellite imagery shows marine stratus across most of the southern Oregon coast and inland into the Coquille Basin. Elsewhere remains cloud free. Our "groundhog" day of summer continues with a ridge of high pressure continuing to dominate the the western United States, including southern Oregon and northern California. However, the ridge is beginning to break down somewhat, and afternoon high temperatures while still hot, will not be challenging records like they have been. That being said, temperatures inland from the coast will be in the 90s to low 100s with higher temperatures in the West Side Valleys. Smoke may continue to be a limiting factor to the heat, but that comes with another set of issues. At the coast, temperatures will still be warm relative to their climatological normals, but temperatures will be in the 70s. The evening shift updated our plethora of heat products and are continuing the excessive heat warning for Siskiyou County. Meanwhile, a heat advisory replaced the previous excessive heat warning across Jackson, Josephine, and eastern Curry Counties while a heat advisory continues for areas east of the Cascades. Additionally, with somewhat cooler high temperatures, overnight low temperatures will be mild with lows in the upper 50s to low 60s. However, smoke from area wildfires may prevent overnight relief from the heat since opening windows is not recommended in areas of degraded air quality. The smoke forecast will largely be downwind (toward the southeast) of area wildfires, with Siskiyou and Modoc Counties forecast to receive the highest concentrations. However, portions of Jackson County-- especially downwind of the Salt Creek Fire, have degraded air quality as well. As such, the Oregon Department of Environmental Quality is continuing their air quality advisory for Jackson County through this morning. Info about the air quality can be found on the Oregon smoke blog: https://oregonsmoke.org Despite the ridge slowly breaking down, temperatures will be similar over the next few days with highs in the low 100s and lows in the upper 50s to low 60s. These temperatures are expected each day through the weekend. Then, over the weekend, a low pressure system will develop off the coast and California and shift northward while remaining offshore. This will bring in some monsoonal moisture and additional energy that could mean thunderstorms. The general thought at this point is that isolated to potentially scattered storms will be limited to areas east of the Cascades, but there are ensemble members that do show a farther west extent while others show a more eastward extent missing us completely. The threat begins Saturday afternoon with Sunday looking to be the more favorable afternoon and evening for thunderstorms. With everything being said and done, there is a 15 to 20 percent chance of thunderstorms for portions of the East Side both Saturday and Sunday afternoon and evening. There is a 5% chance for thunderstorms west of the Cascades for both evenings. Beyond that, we return to a more stable southwest flow pattern with above normal temperatures for interior locations. -Schaaf && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Heat Advisory until 9 PM PDT Saturday for ORZ024-026-029>031. Red Flag Warning from 2 PM to 8 PM PDT Friday for ORZ624-625. Fire Weather Watch from Saturday afternoon through Sunday evening for ORZ624-625. CA...Excessive Heat Warning until 9 PM PDT Saturday for CAZ080>082. Heat Advisory until 9 PM PDT Saturday for CAZ083>085. Red Flag Warning from 2 PM to 8 PM PDT Friday for CAZ284-285. Fire Weather Watch from Saturday afternoon through Sunday evening for CAZ285. PACIFIC COASTAL WATERS...Small Craft Advisory until 8 AM PDT Saturday for PZZ350-356-370. Gale Warning until 8 AM PDT Saturday for PZZ356-376. && $$