science environment

Winter's Coming: 10 Questions For Northwest Weather Experts

By David Stuckey (OPB)
Jan. 8, 2016 7:30 p.m.

Oregon Department of Transportation

We asked two weather experts from the Pacific Northwest 10 questions about the weather ahead in our area. From what mobile app is a must have to the urban myth that Portland is the wettest place in the country. What followed was a mix of vital information and interesting factoids from two weather aficionados that report on the Northwest area daily.

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Q&A with KOIN Meteorologist Sally Showman

Meteorologist Sally Showman

Meteorologist Sally Showman

Sally grew up in Seattle but comes to Portland from Spokane, Washington, — where she was a weekend weather anchor at the ABC station. Sally graduated from Santa Clara University with a degree in journalism. Four years wasn’t enough for her, so in 2012 she completed Mississippi State’s Meteorology Certificate program. You can catch Sally on

KOIN 6

on weekday mornings.

OPB: Where is the wettest place in Oregon?  What about the driest?

Sally Showman: Oregon is an amazing state; we have both desert and temperate rainforest. The wettest place in the state is Laurel Mountain, one of the highest peaks in the Coast Range.  It averages 121 inches of rain per year.  The driest place in Oregon is the Alvord Desert in the southeast corner of the state.  It averages just 7 inches of rain per year.

OPB: What causes hurricane force winds at the west end of the gorge?

Showman: It's a little technical, but let me try to break it down.

Big pressure differences drive the wind. When there is cold air and high pressure east of the Cascades and mild air and lower pressure west of the Cascades, the atmosphere wants to even itself out.  The only sea level passageway for that cold, dense air to travel is through the narrow gap of the Columbia River Gorge.  Air accelerates from high to low pressure, and the western mouth of (the) Gorge becomes a wind tunnel. I’ve been up at the Vista House when winds are gusting to 90 mph.  It’s an incredible experience.  The wind is strong enough to knock you off your feet, or break the hinge on your car door!

OPB: How many tornadoes does Oregon see on the average year?

Showman: Both Oregon and Washington average three tornadoes per year.  Texas averages 155! The vast majority of tornadoes are EF0 or EF1 (the weakest).  In 1972, a rare F3 tornado moved through Portland and Vancouver.  It claimed six lives and caused $3-5 million in damage.

OPB: What is a pineapple express and why is it called that?

Showman: A pineapple express is a stream of very moist air that has roots in the subtropics near Hawaii.  These events often trigger very heavy rain and can cause flooding.  In addition, the pineapple express transports warm air into the region, so it can cause rapid snow melt off in the Cascades.

OPB: Portland has a wet reputation.  Is it really one of the wettest cities in the country?

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Showman: It rains a lot here but when it comes to quantity, Portland isn't anywhere near the top of the charts.  PDX averages 36.03" per year.  The wettest metropolitan city in the country is Mobile, Alabama with an average 67" per year.   On the average year, there are 155 days with measurable rain at PDX.  Mobile averages just 59 days with rain.  The bottom line; Portland outranks most cities when it comes to number of rainy days.  However, torrential downpours and severe weather mean a lot more rain in the south and Gulf Coast.


Q&A with KGW Meteorologist Rod Hill

Meteorologist Rod Hill

Meteorologist Rod Hill

Rod Hill's forecasting career has spanned more than 25 years, taking him from the hurricanes of Texas to the hard to predict weather of the Pacific Northwest. Arriving in the Northwest in 1999, Rod was honored more than any other broadcast meteorologist during his ten years of doing the evening news. Rod has been a lead forecaster at KPTV, KATU and currently KGW television.

OPB: First off, the "Blob," should we be scared?

Rod Hill: The "Blob" has shrunk, I think for now, the answer is no.

OPB: Is Portland the most difficult place you have worked to forecast the weather?

Hill:

No, that would be Grand Rapids, Michigan. Every time the wind speed or direction changes over the Great Lakes, the forecast goes out the window! It is interesting to me that computer models handle Portland’s weather by far, the worst of any city I have worked!  The reason is simple — weather model technology was developed for midwest weather or more dynamic climate locations than we have here in the Northwest.  Because of this, forecasting in the Rose City is very intuitive and something that has to be learned over a period of time.  Figuring out the gorge, the coast, the Willamette Valley and Mt. Hood all takes time and observation.

OPB: Is there one weather App you can not live without?


Hill

: For our local weather — Yes!

PortlandWeather.com

app for iPhone or

PortlandWeather.com/mobile

for android

OPB: Other than Portland of course, what would be the best and worst place to be a meteorologist?

Hill: Worst place is easy, a very boring San Diego.   For best place, I pick Hood River, Oregon.  Living in and studying the gorge on a daily basis would be beyond fascinating!

OPB: Lastly, in one sentence, can you describe what the rest of Oregon’s winter will look like?

Hill: I expect rainfall to be normal or above through March. The big question is the snow level, will it stay near 4,000 feet or go high like last winter?

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