textproduct: Portland

SYNOPSIS

Cooler temperatures will continue through Sunday in the wake of a cold front. Warm and dry Monday through Friday with breezy winds during the afternoon and evening on Monday and Tuesday. The warmest temperatures will occur on Tuesday and Wednesday with highs in the 90s for inland valleys and 70s at the coast, resulting in a Moderate HeatRisk for the interior lowlands. Wildfire smoke is expected to increase west of the Cascades on Monday and Tuesday as winds begin to turn more offshore.

LONG TERM...Tuesday through Friday Night

Models and their ensembles are in good agreement Tuesday and Wednesday will be the hottest days of the week as an upper level ridge over the coastal waters moves inland. Although the ridge axis is expected to move inland, the ridge will be deamplifying at the same time. This will prevent extreme heat with triple digit temperatures from developing. However, it will still be hot with high temperatures somewhere in the low to mid 90s for inland valleys and 70s at the coast. This will result in a Minor HeatRisk at the coast and a Moderate HeatRisk for inland valleys, bringing an increased risk for heat-related illnesses for vulnerable populations that are sensitive to heat. Probabilities for a Major HeatRisk are low, ranging between 5-20% for most inland valley locations. The good news is overnight lows in the mid 50s to lower 60s along with low humidity will offer relief for those without access to air conditioning. Tuesday will likely see hazy skies due to lingering wildfire smoke in the area that is expected to begin pushing west of the Cascades beginning on Monday as low-level offshore winds develop.

The majority of of deterministic and ensemble guidance continue to suggest depict a return to onshore winds by late Thursday and Friday, bringing slightly cooler temperatures but still a bit above average with highs in the mid to upper 80s for inland valleys. The increasing onshore flow late in the week will also help clear out any smoke and haze lingering in the area from mid-week. -23

AVIATION...Through 06Z Mon

VFR conditions over the airspace with scattered cloud cover over the Coast Range and Cascade Foothills. Guidance suggests increasing chances for MVFR CIGs along the coast after 6z through 18z with hourly probabilities of 30-70%. However, this is not a guarantee as the probabilities are not persistent over particular areas from hour to hour. VFR conditions are likely to persist inland but there is a low (20-30%) chance of MVFR CIGs between 10-18z but likely not persistent over one particular area. Probabilities are a bit higher in the southern Willamette Valley at around 60-70%, mainly around KEUG. Light northwest winds around 5 kt overnight, becoming more northerly after 16-18z with wind gusts of 15-20 kt possible.

KPDX AND APPROACHES...VFR conditions through the TAF period, with a 20-30% chance of MVFR CIGs redeveloping between 12-18Z Sun. Northwesterly winds 5-10 kt will continue through the period. -19/12

MARINE

Westerly flow today will shift northerly into Sunday as surface high pressure builds offshore. Chances for maximum wind gusts of at least 21 kt are around 85-95% from Sunday afternoon/evening through at least Tuesday night with the highest relative probabilities across the outer waters. Given this high confidence in Small Craft conditions, a Small Craft advisory was issued for the inner and outer waters, including the Columbia River Bar, starting Monday mid/late afternoon. Once we get in to the middle of the week these Small Craft concerns primarily shift to the outer waters but likely persist through the end of the week. Wave heights through the forecast period remain around 5-8 ft at 7-9 seconds. ~12/99

PQR WATCHES/WARNINGS/ADVISORIES

OR...None.

WA...None.

PZ...Small Craft Advisory from 5 PM Sunday to 2 AM PDT Monday for PZZ210.

Small Craft Advisory from 5 PM Sunday to 5 AM PDT Tuesday for PZZ251-252-271-272.

Small Craft Advisory from 2 PM Sunday to 5 AM PDT Tuesday for PZZ253-273.