Rod's Weather Headlines

Warm November Sets Records

By Rod Hill on 2021-11-30

Our crazy warm November is running at nearly 4 degrees above normal mean temperature as the final day of the month arrives. Depending on today’s numbers, November 2021 may crack the top 5 for warmest November on record.

The last few days have seen three consecutive record highs tied or broken at PDX:

Nov 27 - Record high of 63 degrees

Nov 28 - Record high of 63 degrees

Nov 29 - Record high of 58 degrees

Despite mild overnight lows near 50 degrees, no high-low records have been reached.

Total November rainfall at PDX this month sits at 6.41 inches, well above the monthly norm of

5.45 inches. It may sound crazy, but rain totals would need to top 9 inches to crack the top

5 wettest list. The wettest November on record was back in 2006 when 11.92” of rain was

collected. Still our water year Oct. 1st - Sept. 30th, is off to a good start with a current total of

10.13 inches. The surplus may be smaller than you think at +1.47 inches.

I am eyeing a much colder weather pattern arriving around December 9th, bringing days of snow

to Mt. Hood resorts and chilly valley temps.

Rod Hill

Rain Event Update Shows Some Improvement

By Rod Hill on 2021-11-11

Flood Watch for most of western Oregon and southwest Washington through Friday night. Waves of steady

rain will generally push north up through Portland this morning as warm air advection continues. Heavy

rain rates at times up to .50” of rain an hour with embedded convective activity. There were lightning strikes

near the coast last night. Spotty thunder continues to be possible.

(Flood Watch in dark green)

Early morning temps are near and above 50 degrees including the gorge. Winds today

will be south 10-20 mph, gusty to 35 in elevation and easterly at times in the gorge to 20 mph.

I expect rain to pick up in the north valley through mid-morning. The main rain zone will life north

to Longview early this afternoon, bringing a rain break with showers this afternoon to Portland and Salem.

The rain break will help limit high water spots. 24-hour rainfall today near 1.00” in the flat

of the valley. Temps across the region will be near and above 60 degrees.

TONIGHT: Rain picks up with waves of steady rain overnight, with steady temps in the mid 50s to 60 degrees and south breezes.

FRIDAY: THE MAIN RAIN EVENT as a cold front drops southward into the valley and stalls with the upper

flow pattern overriding. This will be the so called atmospheric river plume of moisture. I expect steady rain,

much of the day and into early evening. 24-hour rainfall amounts will likely exceed and inch and could be

much higher if the front stalls for hours. Temps will hold 60-64 degrees across the region with southwest winds

10-20 mph.

FRIDAY NIGHT: Current timing as the rain dropping southeast of our region during the evening hours and the

rain event coming to a close. Low temps 46-53 degrees. Total rainfall for the 60 hour event will exceed 2.00 inches in Portland.

As of 10:00 a.m. Thursday morning, area rivers are projected to remain below flood stage through the event.

Rod Hill

Update For Heavy Rain Event

By Rod Hill on 2021-11-10

Residents of the northwest bracing for possible heavy rain event this evening through Friday night.

A weak atmospheric river will accompany a warm front tonight to bring hours of steady rain, heavy
at times into Thursday morning. Widespread rain tonight will drop at least .50” of rain over Portland
and Salem with valley amounts possibly nearing an inch. The warmer air will lift snow levels above
8,000’ by morning, meaning all rain at Mt. Hood resorts.

While surface winds will be breezy, south 10-20 mph, wind will generally not be a concern through
the forecast period. People living at elevations above 1,500 feet should expect constant southwest
winds between 20-30 mph. The warm moist air will bring rising temps overnight into Thursday morning,
with much of the Portland area waking up to 55 degrees, rain and ponding of water on area roadways.

A forecast update shows the main fetch of steady, heavy rain will push north of Portland into Washington
during the day Thursday, bringing a respite of steady rain. Daytime rain amounts Thursday may average
as little as .25 inches. Valley high temps will warm into the low 60s.

Rain picks Thursday overnight into Friday morning in what could be a 2nd period of steady, heavy rain
as a cold front drops southward into our region. The front may become nearly stationary during the
day Friday with the atmospheric river transporting rain over the frontal boundary, producing valley rain
totals well over an inch during the day and possible 1.50 inches. As the front drops through our region
Friday night, rain ends for a dry Saturday.

TO RECAP:

2 heavy rain episodes - one tonight and a 2nd Friday daytime. (possible rain break of sorts Thursday afternoon)

Valley rain total: 2.00 -3.00”

Coast rain total: 2.50-5.00”

Coast Range and Cascades rain total: 6.00” and possibly 10” of total rainfall in some drainage basins.

Smaller rivers (meaning not the Columbia or Willamette) may reach flood stage Friday pm hour into the night.
High water spots become possible Thursday morning and again during the day Friday.

Mudslides will be a concern over wildfire burn scars.

Rod Hill

Heavy Rain, Possible Flooding

By Rod Hill on 2021-11-09

A warm front Wednesday evening will lead to steady rainfall overnight, adding up to .50" in Portland and beginning a stretch of mostly steady, heavy at times rainfall through Friday evening. A weak atmospheric river will pump Pacific moisture into a convergence zone along a warm front to stationary boundary Thursday. The moisture flow continues Friday as a cold frontal boundary slowly drops south through our region.

Weather models show more than inch of valley rain Thursday and possibly an inch of rain Friday, making for 60 totals between 1.50 and 3" of rain over the Portland metro and much of the I-5 corridor from Albany to Longview. The Coast Range and Cascades could see rain totals of 6-12" through the period, while the coast sees 2.50-5.00 inches. High water spots or urban flooding are expected, along with possible river and stream flooding Thursday night into Saturday. Mudslides in burn scar areas are also a concern.

Snow levels will be high at 8,000' and above Thursday and Friday, meaning heavy rain in the mountains. Elevations above 1,500 feet may see a constant southwest wind between 20-30 mph through much of the period.

Dry weather is expected to return Saturday, either morning or afternoon.

Rod Hill

Rod's Winter Outlook 2021-2022

By Rod Hill on 2021-10-14

This winter's outlook begins with what is fairly rare, a back to back La Nina winter season. Our region is projected to have a moderate La Nina winter, matching last season's Enso cycle. This will become just the 10th back to back La Nina since the cycle was documented starting in 1950.