Area Forecast Discussion
Issued by NWS Portland, OR
Issued by NWS Portland, OR
641 FXUS66 KPQR 261652 AAB AFDPQR Area Forecast Discussion...UPDATED National Weather Service Portland OR 952 AM PDT Sun May 26 2024 .SYNOPSIS...Warmer and drier with more sunshine across much of the area today, with the exception of clouds and maybe a few passing showers across parts of southwest Washington. Temperatures peak on Monday with highs in the 70s in many locations. Cooler and wetter weather returns from Tuesday through the middle of next week. && .SHORT TERM...Now through Monday Night...Satellite imagery shows mostly clear skies across much the area early this morning as transient shortwave riding crosses overhead, with any lingering cloud cover confined mainly to northern coastal areas and parts of the Cascades. Today will be characterized by benign onshore flow yielding mostly dry conditions as temperatures warm to around 70 degrees in most locations away from the coast. The exception will be over the far northern coastal areas and parts of the Cowlitz River Valley, where cloudier skies will prevail and a few showers can`t be ruled out through this afternoon as a weak disturbance crosses the Washington Coast. Models then remain in excellent agreement on warmer temperatures for Monday as an upper level ridge builds east of the Cascades, allowing highs to push well into the 70s throughout the interior valleys. Guidance has converged on temperatures in the mid to upper 70s around the Portland Metro, with around a 20 percent chance that highs could reach 80 degrees in a few spots. The shift back towards a cooler pattern begins Monday night as the next trough approaches from the Pacific, bringing a chance of rain back to the coastal areas after midnight.-CB .LONG TERM...Tuesday through Saturday...Cooler and wetter weather returns to the region on Tuesday as guidance has continued to incrementally shift the downstream ridge farther east in recent runs, allowing the next trough from the Gulf of Alaska to move over the Pacific Northwest by Tuesday afternoon. This will bring widespread light rain the region Tuesday into Wednesday, with temperatures falling back into the low to mid 60s and snow levels lowering across the Cascades but likely remaining just above the passes. QPF amounts look rather minimal through mid week, with the bulk of guidance depicting no more than one to two tenths of an inch in the lowlands and closer to a quarter to a half inch in the higher terrain through Wednesday. Light shower activity looks to linger into Thursday as northwest flow develops on the back side of the departing trough. WPC ensemble clusters have begun to favor a return to ridgier pattern late in the week, which is reflected by forecast highs climbing back into the 70s from Friday into next weekend. -CB && .AVIATION...A trough far to the north is producing a few intermittent rain showers that clip the northern coast only throughout much of the period. A 50-60% chance of MVFR cigs persists at KAST throughout the rest of the TAF period. For all other areas, light scattered cloud cover and VFR conditions are expected throughout the entire period. Around a 10-20% chance of fog forming in the southern Willamette Valley (KEUG, KSLE) around 12z Monday, but due to low probability, did not put in TAF. West winds at the coast gust up to 10 kt during daytime hours, but all inland terminals see weak gusts under 5 kt throughout the TAF period. /JLiu PDX AND APPROACHES...VFR conditions through the period. Light scattered cloud cover from midday onwards. Variable winds becoming northwesterly in the afternoon but will remain light. /JLiu && .MARINE... Brief showers expected in the northern waters this afternoon as a low pressure system in the Gulf of Alaska tries to push southeastward. This system will notably move into our region late Monday night into Tuesday. Very little impacts are expected as the system is not overly deep and is generally staying more north. Otherwise, will still see generally onshore flow through the forecast period. Will see increased winds late into the week. -JH && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...None. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland