textproduct: Portland

SYNOPSIS

Very hot temperatures today will persist overnight into Wednesday. Highs in the mid to upper 90s expected inland with chances of highs up to 100 degrees F on Wednesday. Monsoonal moisture will move in on Wednesday which will complicate the forecast. Thunderstorm and shower chances increase on Wednesday, especially in the afternoon with additional daytime heating. Widespread lightning not out of the question. Showers persist into Thursday and cooler temperatures expected through the remainder of the week.

LONG TERM...Thursday Night through Tuesday

By Thursday, the ridge begins to weaken as a broader trough moves toward the Pacific Northwest. This should promote a return to more noticeable onshore flow and begin a gradual cooling trend that carries into late week. Temperatures are still likely to remain somewhat above seasonal normals Thursday and Friday, but not to the degree seen earlier in the week. Looking beyond Friday, forecast guidance currently does not show a strong signal for meaningful precipitation, while temperatures trend toward the lower 80s through the weekend and into early next week. -12

AVIATION...Through 06z Thursday

VFR flying conditions expected to continue at inland terminals through much of the period beneath sct/bkn high clouds. Periods of haze from elevated smoke may restrict vis to 5-6 SM in the afternoon. Along the coast, marine stratus will again yield IFR/LIFR cigs/vis, with the highest confidence in restrictions along the central OR coast (KTMK, KONP). Low clouds will erode in the morning, returning to MVFR/VFR conditions by 18-21z Wed. Winds will be calm to light and variable tonight, building out of the west to northwest at 5-10 kt inland and 8-12 kt along the coast after 18z Wed.

Afternoon temperatures are forecast to approach 100 degrees at many inland terminals Wednesday afternoon; be aware of high density altitude which may reduce aircraft performance. Showers and isolated thunderstorms are expected to develop Wednesday afternoon, tracking northward through the remainder of the period. Confidence in the occurrence of thunder is too low to include in TAFs at this time, but heavy showers may briefly result in MVFR/IFR vis if they pass over a terminal. Showers may also produce gusty or erratic winds nearby. Late in the period, winds will begin to turn out of the southwest to south as showers wane.

KPDX AND APPROACHES...VFR conditions expected to prevail through much of the period beneath sct-bkn high clouds. Smoke aloft may yield surface vis of 5-6 SM Wednesday afternoon, although vis aloft can often be lower. Chances for showers or an isolated thunderstorm increase after 00z Thu; the most likely terminal impacts are gusty/erratic winds and locally heavy downpours which may briefly restrict vis to IFR/MVFR levels. Northwest winds continue through the period at 5 kt or less overnight, building to 5-10 kt by Wednesday afternoon. -36

MARINE

A typical summertime pattern will continue through the middle of this week with persistent north to northwest winds over the coastal waters. Winds then shift southwest to westerly Thursday into the weekend as weak low pressure develops over the waters. Winds will remain light less than 10-15 kts. Seas will be 3-6 ft at 8-9 seconds through the weekend.

On Wednesday, there is a chance for showers and thunderstorms across all of the waters through the majority of the day and overnight hours. There could be frequent lightning and gusty and erratic winds with any thunderstorm that forms. -03

CLIMATE

Daily record high minimum temperatures for July 22 Astoria 62 (2007) Vancouver, WA 74 (2006) Portland Int'l 74 (2006) Hillsboro 73 (2006) McMinnville 73 (2006) Salem 74 (2006) Eugene 71 (2006)

Daily record high maximum temperatures for July 22 Astoria 88 (1891) Vancouver, WA 98 (1928) Portland Int'l 98 (1978, 2004) Hillsboro103 (1938) McMinnville102 (1928) Salem102 (1928, 1978) Eugene101 (2006)

PQR WATCHES/WARNINGS/ADVISORIES

OR...Heat Advisory until 11 PM PDT Wednesday for ORZ108>115-120>122.

WA...Heat Advisory until 11 PM PDT Wednesday for WAZ204>210.

PZ...None.