Happy Valley, Oregon, Weather: April 2018

Happy Valley, Oregon, Weather: April 2018

TEMPERATURES

April started off quite cool as the maximum on the 1st remained in the 40s, fooling any thinking that Spring was soon on its way. Minimum temperatures during the first 3 days fell into the 30s, even allowing for some light snow on the morning of the 2nd. Maximums recovered into the 60s for several days but chilly weather was never far off, returning to only the 40s and 50s from the 11th-17th as warm air continued staying far from the area. It wasn’t until the final week of the month that warmth finally sprang into action, reaching 72.9° on the 23rd, the warmest reading since Sept. 28, 2017 when it hit 83.9°. This was quickly outdone as maximums soared over 80° for the next 3 days (24th-26th), a very rare occurrence here in April. The Portland Airport set or tied 3 consecutive maximum temperature records on these 3 days, also all in the 80s, topping out at 86° on the 26th, which tied for the 5th highest reading ever for the month of April there (data period-of-record back to 1940). Following the reading of 84.9° here in Happy Valley on the 26th,, a cold front swept through and drastically dropped temperatures to below normal as the maximum on the 27th was only 56.5°, a 28.4° drop from the previous day. (This maximum of 56.5° occurred right at midnight, the beginning of that day – the afternoon maximum on the 27th was only 55.8°, actually a 29.1° drop from the previous day.) The final day of the month managed to reach a maximum of just 55.1°.  The late-in-the-month warmth turned what would have been a below-normal month into one that was a bit above normal.

Average Monthly Maximum: 61.2°
Average Monthly Minimum:  44.3°
Monthly Mean: 52.7°

 

Monthly High Maximum: 85.0° (25th)
Monthly Low Maximum:  47.7° (1st)
Monthly Low Minimum:   34.5° (3rd)
Monthly High Minimum:  56.5° (26th)

 

NUMBER OF DAYS:
Maximums ≥80°:  3
Maximums ≥75°:  3
Maximums ≥70°:  4
Maximums ≥65°:  9
Maximums ≥60°: 16
Maximums ≥55°: 23
__________________
Minimums ≤50°: 26
Minimums ≤45°: 19
Minimums ≤40°:  7
Minimums ≤35°:  1
Minimums ≤32°:  0

 

PRECIPITATION

It was a fairly cool, cloudy, and damp first half of the month, followed by a rather dry second half. The first 17 days saw 5.59” of precipitation, 86% of the monthly rainfall. The heaviest calendar-day rainfall occurred on the 7th with 1.92”, the highest daily amount since 2.42” fell on Feb. 5, 2017. This was followed the next day with 0.79” (on the 8th). The amount of the 7th was also the first daily rainfall of ≥1.00” since Nov. 15, 2017. Two periods of light snow fell on the morning of the 2nd, but just a Trace was “measured” as temperatures remained a bit above freezing.

For the 9-day period 18th-26th it was dry (except for the 21st when a barely measurable 0.01” of rain fell), a welcome respite from the steadier winter rain and snow. The final 4 days of the month contained the remaining 0.70” of the April total of 6.30”.

Total Precipitation: 6.30″
Maximum Calendar Day: 1.92″ (7th)

 

PRECIPITATION NUMBER OF DAYS (including Snow Water Equivalent):
≥0.01″: 19
≥0.25″:  9
≥0.50″:  3
≥1.00″:  1
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Hail: 1
Snowfall ≥Trace: 1
Snowfall ≥0.1″: 0
Snowfall ≥1.0″: 0
Snow Depth ≥Trace: 0
Snow Depth ≥1.0″: 0

 

MISCELLANEOUS

Sky cover for the month was thus: 6 clear, 9 partly cloudy, and 15 cloudy days were observed. There were 19 days having fog, with only 2 of these being heavy (<1/4 mile visibility). One day of hail was observed on the 7th. The highest barometer reading was 30.44” on the 21st, the lowest reading was the day of heaviest rainfall when the mercury sank to 29.42” on the 7th.  Relative Humidity reached its maximum on the 6th at 100%, its minimum on the 24th at just 21%.

 

Link to the monthly weather form: Happy Valley Weather: April 2018

 

First CoCoRaHS gauge catch of more than an inch since last September – 4/7/2018
Blooming Pear Trees and Rainbow – 4/7/2018

 

Cover Photo: Distant Rain Falling from Clouds – 4/18/2018

 

2 thoughts on “Happy Valley, Oregon, Weather: April 2018

  1. Thanks for posting your April report Jeff. I like the cover photo – looks like virga but I guess the shafts did reach the ground. Sugarloaf Mt in Maine just closed out their ski season this past Sunday, sounded like a “rock ski adventure” with rather patchy cover over their trails. I am sure it isn’t that way at Timberline. Are you all going to be in good shape for the upcoming dry season as far as forest fires go? I guess the fires get started most commonly by “dry lightning” or is it actually from human mistakes?

    1. Hi Kevin,

      Yes, it does appear as virga in the pic but it definitely was reaching the ground to our southeast that day.

      You are correct, Timberline still has a long ski season ahead. They did receive 2″ of new snow yesterday and the base depth was still 133″ as of this morning’s observation. The season total as of this morning has measured 605″. No measurable snow is in the 7-day forecast at the 6000-ft level.

      Northern Oregon has done fairly well with snow/ppt this winter, though a bit below normal. Southern Oregon hasn’t done as well and will likely have more issues this fire season. I don’t know what the percentages are between human and lightning-induced fires out here but my guess is that more are usually started by humans.

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