textproduct: Portland

SYNOPSIS

Now that temperatures have hit "rock bottom" the only way forward appears up, and up into the 90s towards the triple digit mark we shall go. While shower chances linger through Wednesday morning, starting today we embark on a prolonged stretch of warming temperatures day to day culminating in a multi-day heat event focused over the weekend into early next week (June 13-16th). This time period will presents some of the hottest temperatures we've seen so far this year. Don't get caught off guard by our recent stretch of cooler/wet weather and start preparing for heat related impacts now. At least there is growing confidence in a return closer to normal temperatures (70s/80s) by Wednesday of next week.

LONG TERM...Friday through Tuesday

Hot temperatures, likely the hottest of the year so far, are the main driver of our weather impacts through the long term period. Friday through early next week, models and their respective ensembles are in good agreement depicting an upper level ridge amplifying over the far northeastern Pacific before shifting overhead. By Saturday, June 13th, the NBM probabilities for daytime highs above 90 degrees F are 45-75% for the Willamette Valley. NBM probabilities for daytime highs at or above 100 degrees F on Sunday June 14th are 30-50% and 20-70% on Monday June 15th, with the highest probabilities each day towards the northern portions (Portland/Vancouver Metro) of the Willamette Valley. Also, there is a 5-15% chance for daytime highs on June 14th and June 15th of 105 degrees F or higher for locations between Salem, OR and Kalama, WA.

For reference, HeatRisk levels are as follows: Little to None, Minor, Moderate, High and Extreme.

Probabilities for a Moderate HeatRisk or higher on Saturday June 13th are 80-95%, then on Sunday/Monday (June 14th and 15th) 90-99% across almost the entire region. For Major HeatRisk, there is a 50-80% probability on Sunday June 14th and 25-80% probability on June 15th (highest Portland Metro, lowest near Eugene and along the coast). At least through this period the probability for Extreme HeatRisk across the CWA is 5-15% or less. Anyone who is sensitive to heat or those who have outdoor plans should prepare for and takes steps to mitigate potential heat impacts. For those planning to seek relief by swimming in local area rivers and/or lakes to cool off, be mindful of cold water temperatures and swift currents which can become life threatening if precautions like wearing a life preserver is not taken.

By June 16/17th (Tuesday and Wednesday of next week), ensemble modeling systems including the newer AI based suites do hint at the ridge finally breaking down and shifting to the east with westerly flow and thus a noticeable decrease in temperatures finally prevailing. However, there's a large degree of uncertainty as to whether this transition takes place on Tuesday or Wednesday, but at least the majority of models do push temperatures downward back into the 70s and 80s by the latter day (Wed June 17th). The latest NBM only gives the inland valleys a ~15% chance for highs to exceed 90s degrees Wednesday afternoon so confidence is moderate to high in a return closer to normal occurs by the middle of next week bringing the region some much needed relief.

It's worth noting with this upper level pattern, a thermally induced surface trough also will establish itself somewhere west of the Cascade Crest-line which could result in locally breezy winds within the Cascades and/or Willamette Valley depending on its orientation. As daytime highs increase, relative humidities will also decrease. Therefore, with conditions drying out AND the potential for gusty winds, there are increasing fire weather concerns for the latter part of this week through the start of next week. So, be aware of potential ignition sources such as chains dragging on the pavement, hot vehicle components, as well as cigarette butts as these could easily result in the ignition of dry, fine fuels. Larger fuels may not have the time to dry out, but this is a variable that is being closely monitored by State and Federal Fire Partners. -99/42

KPDX AND APPROACHES

We'll likely maintain a mix of high-end MVFR/low-end VFR through 18-19z, then predominately VFR afterwards. Showers decrease in frequency during the afternoon but may still pass within the vicinity of the terminal (or overhead) from time to time. South-southwesterly winds with gusts up to 25 kt turn more westerly during the afternoon. -99

MARINE

Early this morning broad westerly flow has returned across the waters as our most recent frontal system begins to depart to the east. Seas around ~9-10ft at 9-10 seconds are expected to peak this morning before slowly decreasing the remainder of the day while westerly winds continue to gust around 15-25 knots. Thus, conditions across both the inner and outer waters including the Columbia River Bar likely remain under Small Craft conditions into the evening hours after which point seas and winds calm further. From here our focus shifts to high pressure building offshore through the remainder of the week. West winds of 7-15 kt on Wednesday will steadily shift out of the north. Typical summertime northerlies lock in place from this point forward, reaching their diurnal peaks of 15-25 kt each afternoon and evening from Thursday through the weekend. This may necessitate daily Small Craft Advisories, especially beyond 10 NM south of Cape Falcon. Seas will persist at 4-8 ft at 9-11 seconds with a continued westerly swell. -99

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ210- 251>253-271>273.