textproduct: Portland

SYNOPSIS

Warm and sunny conditions continue through Monday as high pressure builds over the region. This will result in localized Moderate HeatRisk across the inner Portland Metro, Columbia River Gorge, and Upper Hood River Valley. An upper- level trough moving into British Columbia Tuesday to Wednesday will cool temperatures a few degrees and a 15-20% chance for light rain along the south Washington and north Oregon coast. Late in the week, persistent onshore flow will maintain seasonable temperatures. Make sure to practice water safety when swimming in local rivers.

SHORT TERM...Today through Monday

Satellite imagery and surface observations as of early Sunday afternoon depicts sunny skies across northwest Oregon and southwest Washington as high pressure builds aloft. Clouds have cleared out much sooner today, so expect temperatures to be a few degrees warmer than the previous couple days. Afternoon highs today are forecast in the mid 80s across interior valleys and 60s along the coast. Onshore flow will prevail, so guidance is suggesting a return of marine clouds along the coast late tonight into early Monday morning.

The warmest day of the week is expected tomorrow with high temperatures peaking in the upper 80s across interior valleys while the coast remains in the 60s. Chances for exceeding 90 degrees remain around 10-35% chance across the Willamette Valley, 50-75% chance along the central Columbia River Gorge the Upper Hood River Valley, and less than 10% for the rest of the interior valleys. For these locations, there will be some localized Moderate HeatRisk, meaning this level of heat will affect those sensitive to heat, especially those without adequate cooling or hydration. Low temperatures in the 50s across the entire area should provide decent overnight relief from the heat. Everywhere else will remain in Minor HeatRisk.

It is important to remember that while temperatures will be warm this holiday weekend and next week, many local lakes and rivers remain very cold and can cause cold water shock. Also, rivers may still have swift currents in some areas, which can quickly sweep you away. Please practice water safety by wearing life jackets, visiting with a buddy, and always being aware of your surroundings. -10

LONG TERM...Tuesday through Saturday

Tuesday to Wednesday, ensemble guidance continues to show an upper-level trough from the Gulf of Alaska moving east/southeastward into British Columbia. This system is expected to stay northward, keeping northwest Oregon and southwest Washington predominately dry. However, could see a 15-20% chance for precipitation along the north Oregon and south Washington coast. Despite the lack of precipitation, this system will still maintain onshore flow and keep temperatures near seasonal normals. West-northwesterly winds are generally expected to be light for most areas during this time. However, will see locally breezier winds along the central Columbia River Gorge and Upper Hood River Valley, where there is a 35-45% chance for at least isolated wind gusts exceeding 40 mph Tuesday and Wednesday.

Thursday, most ensemble members show the aforementioned trough weakening as it moves eastward through British Columbia and returning dry, zonal flow over the Pacific Northwest. By Friday- Saturday, ensemble members are showing additional troughing moving down from the Gulf of Alaska into the northeast Pacific/British Columbia. There still remains uncertainty with the exact placement and magnitude of this additional troughing, but generally this system remains far enough north to keep us dry. If this pattern does pan out, this would support continued onshore flow with seasonable temperatures and little to no precipitation. -10

AVIATION

VFR through the day including the coast. Northerly winds continue to amplify today with gusts up to 20 kt along the coast and the southern Willamette Valley from KSLE south. There is around a 60% chance of gusts greater than 20 kt around KEUG and the Coast Range Foothills but less than a 10% chance in the north.

Overnight, there is a non-zero chance of MVFR conditions redeveloping, however the high pressure ridge will be much stronger into Monday and thus drier air will be present at the surface and aloft. It will be much more difficult to get lower cloud development - especially inland. Winds too will ease overnight with very low probability (less than 5%) of gusts up to 20 kt.

KPDX AND APPROACHES...VFR with no concerns. Northerly winds increase in the afternoon. Some models suggest around a 90% chance of wind gusts greater than 20 kt while others are closer to 50%. Have not included gusts to these levels, but the time frame in which they would occur would be between 00Z-06Z Mon. -27

MARINE

High pressure over the region is leading to the formation of a thermal trough over the waters. The typical summertime pattern means that we are seeing gusty northerly winds over all of the outer and inner waters, with wind waves increasing. Seeing anywhere from 20-25 kt gusts over the waters, with buoy 46050 reporting gusts up to 27 kt this afternoon. This will be the trend over the next several hours for the northern waters, then will slowly dissipate. Have extended all of the small craft advisories, maintaining a staggered cancellation moving from north to south. The northern waters will ease first, following by the central and lastly the southern. Seas will generally remain around 7 to 9 ft at 10 seconds but it's not uncommon for northerly winds like this to compound with the primary northwesterly swell direction. Thus, the wind wave may bring isolated 10 ft seas - though not expected to be widespread or long lasting.

Conditions will ease on Monday as a long wave trough and associated shortwave energy surges move over the region on Wednesday. -27

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Small Craft Advisory until 5 AM PDT Monday for PZZ251-271.

Small Craft Advisory until 11 AM PDT Monday for PZZ252-253-272- 273.