textproduct: Medford

DISCUSSION

A potent cold front and upper level low pressure system is swinging through the region today through tonight, bringing moderate/heavy rain, mountain snow and gusty winds. Pressure gradients will peak this afternoon, with mid-level winds peaking around 55 kt. It will be windy everywhere today, with gusts of 20-30 mph common, even for West Side areas. We expect widespread peak wind gusts in the 40-50 mph range for areas from the Cascades eastward, perhaps 55 mph in some areas. Wind advisories have been issued for portions of Lake/Modoc counties where winds will be strongest, and now also include the Shasta Valley where a quick burst of pre-frontal south winds (with gusts to 45 mph) are expected today before they shift to southwest during the afternoon. Strong winds are also expected along the coast, but should remain just below warning levels. With model pressure gradients (OTH-ACV) showing -8 to -9, it's possible that the capes and headlands, especially Cape Blanco, could briefly see gusts up to 60 mph, but overall, gusts in the 40-50 mph range are the more likely scenario for the majority of the immediate coastline.

The sharp cold front will blast through the area this afternoon and this will bring periods of moderate rainfall along with heavy mountain snow (mostly above 5000 feet). The heaviest precipitation is expected from the coast to the Cascades through this afternoon. Other than some minor/typical nuisance ponding of water on roadways, we are NOT concerned about flooding since river levels are very low for this time of year. Most of the rain expected from this system will be beneficial/welcome. Amounts of 1-3 inches are likely along the coast, with 0.50-1.00 inch common inland to the Cascades with 0.25-0.50 inch over the East Side. Snow levels currently hover around 5000-5500 ft, but will drop to 2500-3000 feet by Thursday morning. We have Winter Storm Warnings up for the Cascades where snowfall rates could be 1-2" per hour at times this afternoon during the height of the precip. Timing for highest snowfall rates appears to be 1-5 pm. It should be noted that as the cold pool aloft moves in behind the cold front, instability increases over the marine waters and inland late this afternoon into tonight. This could generate isolated thunderstorms, most likely along the coast (50-70% chance) with lower probabilities into the Umpqua and east of the Cascades (20-40%).

With snow levels crashing down to around 2500 feet tonight, Winter Weather Advisories are also up for the Siskiyou Mountains and for the "spillover" area east of the Cascades (Highway 97 corridor) and the mountains east of there (Warners), where a few to several inches could accumulate. All in all, expect significant winter travel impacts in the mountains and over some of the higher passes, especially at Lake of the Woods by Thursday morning. Main I-5 passes should be OK, but some slippery spots could develop at Siskiyou Summit and/or around Mt Shasta City/Snowman Summit early Thursday morning. There could be a little dusting of snow too for some of the lower spots in NorCal and over the East Side, but ground temperatures are warm, so most non-mountainous locations won't see road accumulation (exception Chiloquin northward). Even some of the higher spots around the west side valleys (~2500 feet) could see snowflakes in the air Thursday morning, but snow accumulations are unlikely given the warm ground temperatures and relatively light precipitation rates being unable to overcome these warm ground temperatures.

With the core of the upper level cold pool shifting into northeast Oregon and Idaho on Thursday, showers and perhaps an isolated thunderstorm will continue for a while into the afternoon, but then diminish rapidly around sunset as high pressure builds in. Models continue to show a high probability (70-90% chance) of temperatures dropping into the low to mid 30s for the west side valleys by Friday morning. So, that will bring frost/freeze risk, depending on how quickly cloud cover diminishes Thursday night. Greatest risk of that occurring is in the Illinois Valley (Cave Junction/Obrien/Selma), but also here in the Rogue Valley. The probability of temperatures less than 28F have also increased, a 10-20% chance here, with around 40% chance from around Cave Junction southward. We've gone forward with a Freeze Watch for Jackson/Josephine Counties as well as the Klamath River Valley in western Siskiyou. Climatologically speaking, areas east of the Cascades and in the Shasta/Scott Valleys still frequently see frost/freeze conditions this time of year, so no products are considered for those areas at this time. We may need to consider the need for Frost Advisories for portions of the Umpqua Basin and potentially along the coast, but confidence is lower for those areas on there being enough clear skies to lead to frost conditions. Stay tuned for updates.

Models are showing the upper ridge rebuilding across the area Friday into the weekend, so look for temperatures to rebound to above normal levels again (highs in the 70s and even low 80s again west side valleys) along with little to no chance at precipitation. Next chance at precip won't be until Monday at the earliest, but more likely Tuesday/Wednesday next week. Early indications show that the next potential precip event will be shorter-lived than the current system, with lower amounts and also less wide-spread. -Spilde/BR-y

AVIATION...(18Z TAFs)

A passing front today will bring widespread precipitation and low/mid level clouds which will result in widepsread MVFR. Conditions will remain this way through most of this cycle, but showers should start to thin out tonight and become more isolated. The front will also bring breezy wind speeds with a shift expected later this afternoon behind the front. Gust around 15-25 mph will be common today, but a brief gust of 30 knots is not out of the question. Also, with the front passing we could have period of low level wind sheer, but this threat should diminish this afternoon when mixing occurs. Lastly, isolated thunderstorms will be possible this afternoon as well.

MARINE...Updated 1100 AM PDT Wednesday, April 1, 2026

A strong cold front will maintain south gales (gale warning in effect) and very steep seas along with periods of rain and reduced visibility through early this afternoon. Isolated thunderstorms are possible this afternoon and tonight. While winds are expected to ease this evening, very steep seas are expected to continue through Thursday morning. A Hazardous Seas Warning is in effect until 2 pm Thu. Swell- dominated seas gradually subside, but remain steep through Thursday evening. Advisory strength north winds are likely to return late this week into the weekend with steep, wind-driven seas.

MFR WATCHES/WARNINGS/ADVISORIES

OR...Winter Weather Advisory from 8 PM this evening to 11 AM PDT Thursday for ORZ029-030.

Freeze Watch from late Thursday night through Friday morning for ORZ024-026.

Wind Advisory until 5 PM PDT this afternoon for ORZ031.

Winter Storm Warning until 5 PM PDT Thursday for ORZ025-027-028.

CA...Winter Weather Advisory from 8 PM this evening to 11 AM PDT Thursday for CAZ080-085.

Freeze Watch from late Thursday night through Friday morning for CAZ080.

Wind Advisory until 5 PM PDT this afternoon for CAZ081-085.

PACIFIC COASTAL WATERS...Gale Warning until 2 PM PDT this afternoon for PZZ350-356-370-376.

Hazardous Seas Warning until 11 AM PDT Thursday for PZZ350-356- 370-376.