textproduct: Portland

SYNOPSIS

Minimal change in the forecast overall. Upper level high pressure builds over the far northeast Pacific into western WA/OR over the next several days, ushering in a prolonged stretch of dry and hot conditions. Daytime temperatures increase significantly this weekend into early next week, peaking Sunday and Monday with interior lowlands in the upper 90s to around 100 degrees. Low temperatures will not provide much relief from the heat. Heat related impacts are anticipated for much of the region with widespread Moderate to High HeatRisk. Temperatures will trend cooler for Wednesday onward with the return of onshore flow.

LONG TERM...Tuesday through Friday

Ensemble guidance indicates high pressure continues Tuesday with heights beginning to lower along with 850 mb temperatures, which would allow for lowering temperatures on Tuesday. However, there is uncertainty in the forecast spread of both of these elements, leading to uncertainty in the high temperature for Tuesday. Additionally, it is not uncommon for models to degrade highly amplified ridges such as this one too early in the extended forecast period. There is no robust weather system in the models that is causing the lowering heights, so there is the potential that the high pressure may not break down as much as ensembles indicate on Tuesday. NBM still indicates warm daytime temperatures at least in the upper 80s for the interior lowlands. Ensembles are in good agreement that the surface thermal trough over OR will break down sometime Monday into Tuesday, so Tuesday is not expected to be quite as warm for the coast and Coast Range. With the flattening ridge, we there is the potential for a more unique wind direction pattern though. We will see a transition to northwesterly winds which will usher in cooler air to the northern portions of the forecast area while the southern zones will remain warmer. Therefore, there may be a 5 degree spread between the north and south on Tuesday. But, if the ridge remains amplified, that difference will be less significant. Either way, past heat events have shown that impacts from the heat can continue despite a cool- down, especially since morning low temperatures are expected to remain very warm Tuesday morning.

Ensemble guidance indicates the high pressure axis shifts west back over the E Pacific Wednesday and Thursday as a strong upper trough digs into the Midwest. However, uncertainty in the strength of the trough leads to uncertainty in the high pressure over the Western US/E Pacific. There is high confidence that temperatures will be quite cooler than Sunday and Monday, but 50-60% of ensemble members still keep just enough high pressure over the region for high temperatures to remain in the low to mid 80s for the interior lowlands. -HEC

AVIATION

VFR conditions under clear skies across the airspace through at least the remainder of the TAF period. High pressure offshore will maintain northerly winds. Expect 7-10 kt winds across the airspace with gusts up to 25 kt along the coast. Winds decrease to less than 6 kt around 07Z-10Z Saturday.

KPDX AND APPROACHES...VFR under clear skies through the at least the remainder of the TAF period. Northerly winds 7-10 kt, with winds decreasing to less than 6 kt around 07Z-10Z Saturday. /42

MARINE

Expect a typical summertime pattern persist into next week as high pressure builds offshore. Diurnal northerly winds will strengthen, peaking each afternoon and evening. Expect winds of 15-20 kt with gusts up to 25 kt south of Cape Falcon on Friday, increasing to 15-25 kts with gusts up to 30 kts on Saturday. Overnight, wind gusts may fall below Small Craft Criteria for the inner water zones, but still expecting gusts up to 25 kt for the outer waters. Will maintain the current suite of Small Craft Advisories, but they could get extended through Sunday as there is minimal changes in overall conditions. Seas 4-7 ft at 9-11 seconds with a persistent westerly swell.

Long-range guidance brings a more active weather pattern towards the end of next week. Which could result in seas near 10 ft as well as gusts up to 30 kt, but overall confidence in this pattern change is low at this time.

CLIMATE

Record high temperatures and warm low temperatures for Sunday, June 14

High Temperatures: Warm Low Temperatures: Portland Int'l 89F (1988) 62F (1985) Vancouver, WA 93F (1986) 61F (1931) Hillsboro 96F (1961) 60F (1963) McMinnville 93F (1986) 59F (1936) Salem 92F (1961) 59F (1936) Eugene 92F (1914) 57F (1993) Astoria 86F (1914) 58F (1972)

Record high temperatures and warm low temperatures for Monday, June 15

High Temperatures: Warm Low Temperatures: Portland Int'l 95F (1966) 60F (1969) Vancouver, WA 95F (1930, 1966) 62F (1961) Hillsboro 99F (1961) 60F (1963) McMinnville 96F (1961) 59F (1936) Salem100F (1966) 59F (1931) Eugene 96F (1966) 60F (1961) Astoria 91F (1966) 58F (1997)

Record high temperatures and warm low temperatures for Tuesday, June 16

High Temperatures: Warm Low Temperatures: Portland Int'l 95F (1958) 60F (2012) Vancouver, WA 92F (1961) 67F (1966) Hillsboro100F (1961) 65F (1961) McMinnville 98F (1961) 59F (1966) Salem 97F (1961) 61F (1961) Eugene 95F (1961) 62F (1961) Astoria 87F (1958) 59F (1997)

PQR WATCHES/WARNINGS/ADVISORIES

OR...Heat Advisory from 11 AM to 11 PM PDT Sunday for ORZ101>103. Heat Advisory from 11 AM Sunday to 11 PM PDT Tuesday for ORZ104>108-113>119-121>125. Extreme Heat Warning from 11 AM Sunday to 11 PM PDT Tuesday for ORZ109>112-120. WA...Heat Advisory from 11 AM to 11 PM PDT Sunday for WAZ201. Heat Advisory from 11 AM Sunday to 11 PM PDT Tuesday for WAZ202>205-208-210. Extreme Heat Warning from 11 AM Sunday to 11 PM PDT Tuesday for WAZ206-207-209. PZ...Small Craft Advisory until 5 AM PDT Sunday for PZZ252-272. Small Craft Advisory until 5 AM PDT Sunday for PZZ253-273.