675 FXUS66 KPQR 072100 AFDPQR Area Forecast Discussion National Weather Service Portland OR 200 PM PDT Mon Apr 7 2025 .SYNOPSIS...Cool and showery weather continues through Tuesday night, with isolated thunderstorms capable of producing small hail this afternoon. Drier and warmer conditions return briefly by the middle of the week, before additional progressive systems bring further chances for rain showers late Thursday into the weekend. && .DISCUSSION...Tonight through Sunday...Current radar shows widespread showers across the forecast area this afternoon. Have already seen a few lightning strikes across the forecast area and am expecting these showers and possible thunderstorms to continue through at least this evening. The cause of these showers is a broad, upper-level low which has a number of embedded shortwaves. These shortwave will continue to track over the region and will maintain widespread showers and a 15-30% probability of thunderstorms tonight and tomorrow. Model soundings continue to show CAPE values around 250 J/kg. In addition to the CAPE values slightly cooler 850 mb temperatures (0C to -2C) will help support the thunderstorms as well as bringing snow levels down towards 4000 ft through tomorrow. Any thunderstorms that develop today and tomorrow will have the potential of producing small hail of pea size or smaller (0.25 inches in diameter or smaller). Given the showery nature and lowering snow levels, have issued a Winter Weather Advisory for the WA State Cascades. Elevations above 4000 ft could see snow accumulations of 6-12 inches over the next 24 hours. Highest accumulations expected above 5000 ft. Otherwise, rain showers are expected to persist with showers slowly decreasing in coverage through Tuesday night. Daytime high temperatures will continue to run slightly below average, with highs in the mid 40s to upper 50s and overnight lows in the mid 30s to mid 40s. Locales in the Cascade foothills as well as the highest elevations of the Coast Range will see the coolest overnight lows in the low to mid 30s. A pattern change is on deck for Wednesday and Thursday. An upper-level ridge will build over the region and bring drier and warmer conditions. Afternoon highs generally in the mid 50s to mid 60s each day, while overnight lows fall into the upper 30s to upper 40s. However, Thursday will be the warmest day this week and areas within the Willamette and Cowlitz valleys will likely (75-85% probability) warm into the low 70s. Friday into the weekend, another pattern change looks to be in the cards. 500 mb WPC clusters show a majority of the model families (GFS, ECWMF and Canadian) show some form of troughing over the Pacific NW, which means cool and wet conditions are likely to return. Still, there is some uncertainty in the forecast for the latter part of the week and into the weekend. /42 && .AVIATION...A frontal system continues to move through the region, bringing widespread showers and a mix of MVFR/low VFR CIGs for most terminals. Showers will begin to deteriorate around 00Z Tuesday, so expect many terminals to improve to VFR by then. After 00Z Tuesday, the Willamette Valley will have a 20-50% chance for MVFR CIGs, highest chances overnight around 06-12Z Tuesday. As for the coast, a 40-80% chance for MVFR conditions (highest chances around 12Z Tuesday). Additionally, coastal terminals have a 10-30% chance for IFR conditions after 12Z Tuesday. Otherwise, expect southerly to southwesterly winds around 10-15 kt with gusts around 20-25 kt at any given terminal through most of the TAF period. KTTD and KEUG could see gusts up to 30 kt at times. Coastal terminals could see sustained winds up to 20 kt with gusts up to 30 kt after 03-06Z Tuesday. There is also a 15-30% chance for thunderstorms across the region today, with the highest chances before 06z Tuesday. Any passing thunderstorms have the potential for producing lightning, small hail, and heavy rain. During periods of heavier rain, brief VIS reductions to IFR/MVFR are possible. Note: The KAST anemometer remains inoperative. Therefore, KAST TAF amendments are limited to CIG and VIS. PDX AND APPROACHES...Weakening showers continue, with conditions gradually improving to mostly VFR. Expect these VFR conditions to continue until 12Z Tuesday, with chances of MVFR around 20-30%. After 12Z Tuesday, could see CIGs lower to MVFR (MVFR chances around 30-40%) and persist through the rest of the period. There is also a 15-30% chance for thunderstorms until 06Z Tuesday. Heavier rain may reduce VIS at times to 3-5SM. Expect southerly to southwesterly winds today with gusts up to 20-25 kt. ~Hall && .MARINE...A frontal system continues to push through the waters today, maintaining breezy southerly winds 15-20 kt with gusts up to 25 kt. A westerly swell also continues today, maintaining seas around 9-11 ft at 14 seconds. Tomorrow (Tuesday), a low pressure system will move through the waters, increasing southerly winds to 20-25 kt with gusts up to 30 kt. High-end small craft wind gusts are likely, with occasional gale-force wind gusts up to 35 kt. Currently, the most likely timeframe for occasional gales would be between 5 AM to 11 AM Tuesday as the low enters the waters. Decided against issuing a Gale Warning since confidence is low for widespread, long-lasting gale force wind gusts. However, with wave heights expected to increase to 11-13 ft and wave periods around 12 to 14 seconds, have issued a Hazardous Seas Warning from 2 AM to 5 PM Tuesday for all of the coastal waters. Brief Small Craft Advisory seas will linger thereafter between 5 PM to 11 PM Tuesday. More benign marine conditions return Wednesday as high pressure re-builds over the region. However, more active weather returns toward the end of the week. ~Hall/Alviz && .BEACH HAZARDS...A westerly swell around 9-10 ft at 14 seconds will bring an increased threat of sneaker waves through this evening. Therefore, a Beach Hazards Statement for sneaker waves remains in effect until 8 PM today. Beach goers should remain aware of their surroundings. Waves can run up significantly farther on a beach than normal, including over rocks and jetties. Sneaker waves can suddenly knock people off of their feet and quickly pull them into the frigid ocean which may lead to serious injury or drowning. -Hall && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...Winter Weather Advisory from 5 PM this afternoon to 5 PM PDT Tuesday for WAZ211. PZ...Small Craft Advisory until 11 PM PDT Tuesday for PZZ210. Small Craft Advisory until 2 AM PDT Tuesday for PZZ251>253- 271>273. Small Craft Advisory from 5 PM to 11 PM PDT Tuesday for PZZ251>253-271>273. Hazardous Seas Warning from 2 AM to 5 PM PDT Tuesday for PZZ251>253-271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland