textproduct: Portland

SYNOPSIS

Fairly seasonable early July conditions continue the rest of the week into the weekend. Expect a gradual cooling trend Tuesday and Wednesday as an upper-level trough passes north of the region and increases onshore flow locally while allowing for more prolific morning low clouds, especially Wednesday morning. Temperatures remain fairly close to normal into the first half of the weekend before a ridge of high pressure amplifying to our east allows temperatures to trend warmer into early next week.

LONG TERM...Thursday through Monday

By the end of the week most ensemble members show the aforementioned trough weakening as it continues to move eastward through British Columbia and into Alberta. As the trough looses synoptic influence over the Pac NW, the Great Basin high is expected to strengthen while an additional trough slowly drops over the eastern Pacific from the the Gulf of Alaska. There still remains a fair amount of uncertainty in the forecast late weekend into early next week due to the exact placement of this developing eastern Pacific trough, but the resulting southwesterly flow shown by most ensemble members likely leads to a gradual warming trend. -99/47

AVIATION

Onshore flow will maintain a typical summertime pattern across the region. Marine stratus continues to push on;and along the coast, supporting sub-VFR conditions at KAST and KONP. CIGs around or below 1000 feet expected to persist through 18z for both terminals before gradually lifting. There is around a 20-30% chance for stratus with MVFR CIGs to reach inland terminals after 12z Tue. Chances for stratus to reach the southern Willamette Valley around KEUG are slightly higher at 30-40% starting around 8z Tuesday. Northwest winds decrease to less than 5 kt overnight then increase again late Tuesday morning to around 10 kt.

KPDX AND APPROACHES...Predominately VFR conditions expected through at least 12z Tuesday. There are low chances (20%) of MVFR stratus developing after 12z Tue. Northwest winds expected to weaken overnight, then increase to around 10 kt late Tuesday morning. -19/DH

MARINE

High pressure will maintain north to northwesterly winds across the coastal waters through the week. Winds around 15-20 kt this afternoon will decrease through Tuesday as a weak cold front dropping out of the of Gulf of Alaska is expected to fall apart. Seas around 6 to 7 ft are also expected to subside to around 4 to 5 ft through Wednesday. Pressure gradients briefly tighten again both Wednesday and Thursday evenings, with gusts generally up to 15-25 kt, strongest across the coastal waters south of Cape Foulweather. Another weak front will likely approach the waters on Friday returning more benign conditions. /DH

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...None.