9pm…Storm Wrapup

October 25, 2014

It ended up being a decent windstorm for us.  Not a really big storm, but not just a windy day either.

  • 76,000 PGE customers out at the height of the storm.
  • Peak gust 49 mph at PDX, 51 mph at Salem
  • This was the strongest October windstorm in my career here in Portland (23 years)
  • My forecast windspeeds at 10pm last night were a little high.  I said 45-60 mph gusts and most spots were close to 45.  That said, at the time there were no watches/warnings/advisories up for wind and none showed up until 3am, so I don’t feel too bad.

Here are the peak gusts…

plot_wind_metro_peakgusts

A 60 mph gust didn’t make it onto the map in the SW hills of Portland and a 47 mph gust in the Felida area north of Vancouver.  There was a 70 mph gust reported down at sea level at the Port of Vancouver.  That doesn’t appear to reflect reality, so I’m calling cow dung on that one.  Especially with Vancouver Airport 43 mph just a mile or two away!

Spread out over the entire area, this storm was stronger than anything we saw last winter.  Yes I know in mid February there were gusts over 50 mph in a swath right through the middle of Portland, but most other locations had stronger wind today. Couple that with leaves on the trees and that’s probably how we got so many more lines down.

The low track and intensity was pretty good, although models were a bit too high on the central pressure, it ended up close to 980 millibars instead of the 985-990 models forecast.  Wind speeds were slightly too strong on the wind gust graphics from the WRF-GFS and ECMWF, although close enough!  Pressure gradients were forecast well (16.9mb EUG-OLM), although peak wind generally showed up well before the peak gradient from Eugene to Olympia.  The EUG-PDX gradient peaked at 9.9mb.

Hope you all had fun tracking/following it!  And of course I hope that you all get power back on soon too.  It’s going to take awhile…

What are YOUR thoughts on the storm?  Go ahead, my feelings aren’t easily hurt.

Chief Meteorologist Mark Nelsen


2pm Wind Gusts: Salem Gusts over 50 mph

October 25, 2014

Salem and Aurora have both gone above 50 mph now, although Aurora had that gust way back with the initial wind arrival between 11am-Noon.

Here are the peak gusts so far…

PLOT_Wind_Metro_PeakGusts


1:30pm Update: Strong Wind Arriving

October 25, 2014

Quite a burst of strong wind moved through the metro area the past hour, heralding the storm’s arrival.

Peak gust of 45 mph at Hillsboro, 46 at McMinnville, & 44 at Salem.  The Yaquina Bay Bridge had a gust to 71 mph and on Meares Hill (west of Tillamook), a gust to 87 mph.

Wind should increase the next hour or two, remain gusty through sunset, then die down quickly after that.

The low pressure center is moving north quickly, a nice circulation shown on radar west of the Columbia River mouth.

codnexlab.NEXRAD.LGX.N0Q.20141025.2013.024ani

As of 1:25pm there are around 7,000 PGE customers out of power and that number should climb into the tens of thousands this afternoon.  At least it’s mild outside and no one is going to get very cold!

Still thinking anywhere in the metro area we will see gusts between 45-60 mph.  That goes for the Willamette Valley and Kelso/Longview areas too.

Chief Meteorologist Mark Nelsen


Afternoon Wind Storm More Likely

October 25, 2014

All models and the NWS are now hopping on the Windstorm Express!

Here’s the latest at 8:40am…

  • Gusty south wind will arrive in the western valleys around Eugene by noon
  • It then spreads north to the Portland metro area sometime in the early afternoon
  • Southerly gusts 45-60 mph are likely.
  • National Weather Service has issued a High Wind Warning for the Portland Metro Area and valleys.
  • We haven’t seen widespread gusts in this range in quite a few years…especially if lots of us get over 50 mph.
  • Coastal gusts will be in the 70-80 mph range on the central coast, maybe a bit lighter on the north coast.  Same timing as valleys
  • Prepare for lots of power outages and some trees knocked down
  • As the wind starts to arrive around noon, temperatures may jump close to 70 briefly…enjoy that!
  • Wind will be much calmer after 7pm

12z models are in agreement, even our weak RPM shows wind gusts around 50 mph through the whole valley now.

rpm_3pm

The 12z NAM has stronger gusts than the 00z showed:

nam_2pm

The 12z WRF-GFS isn’t out yet.

I’m still a little concerned about the mature-looking low.  Totally wrapped up in itself which isn’t generally a good sign.  But it won’t be weakening much and its movement will be accelerating.

There are very few cases of a deep low moving so close to the coastline at such a steep angle (south to north).  Generally lows track more SW-NE.  I scanned a bunch of past storms and found just one that was similar in track and depth…March 1, 1974.  Here is a link to Wolf Read’s summary of that storm.  It produced a gust to 61 at PDX and 64 at SLE.  The center of this low will be a bit farther north though.

I’ll be at the OMSI What Will the Winter Be Like meeting until around noon, then probably post after that time.  By the way it’s free, from 10am to noon, and in the auditorium.

Chief Meteorologist Mark Nelsen

I


Tough Forecast: Will There Be A Wind Storm Saturday?

October 24, 2014

11pm Friday…

The chance of strong wind in the Willamette Valley and Metro area Saturday has dramatically increased this evening, but it’s definitely not a “done deal”.  Here’s the latest:

  • Models have come together with MOST of them showing a surface low tracking north along the coastline quickly tomorrow afternoon.
  • Air rushes in the south side of the low as it moves north quickly, thus a gusty south wind behind it.
  • My latest thinking is wind gusts 40-50 mph possible from Portland down to Eugene.
  • Two models imply the wind could be significantly stronger in the central valley….gusts 60+.  If so, that would be the strongest Willamette Valley windstorm in years.
  • Prepare for power outages and some downed trees if either scenario occurs.
  • Whatever happens will be done after just 2-4 hours, then back to the usual showers and breezes through Sunday.
  • As of 11pm, there are no watches/warnings/advisories from the NWS and no media freak out.  It’s a bit weird.  We’ll see if that changes in the next 12 hours.

So what has changed?

This evening’s model runs have mostly all (ECMWF comes out in 20 minutes) converged on a low center tracking in the perfect path…right along the coastline and then inland over SW Washington.  That’s the GFS, NAM, and GEM.

They also don’t show the surface low “filling”, or pressure rising within the low, like they did this morning and on earlier runs. Plus the pressure is lower on the earlier runs.  What caught my eye this evening is the very strong wind field over us as the isobars line up with the Willamette Valley.  Take a look at the WRF-GFS sounding over Portland…50kts just off the surface up to around 70kts at 850mb (~4,500′)

wrf_2pm_sounding

We don’t often see the wind field at all elevations aligned directly south to north at the same time the pressure gradient at the surface jumps up from Eugene to Portland.  The WRF-GFS goes nuts, showing 55kt wind gusts (around 65 mph) in the central valley.  Other than earlier this week, I’ve never seen this model show such strong wind in that area.

wrf_2pm_windgust

The NAM is not quite as strong, although it still shows gusts around 50 mph in the valley.  Models still don’t show the low deepening as it moves north; that would be a major windstorm.

Hmmm, a few other hints.  moswind  The 00z GFS MOS (model output statistics) shows an unusually high south wind averaging 24 mph at 2pm as well.  We don’t see it go that high very often.  The Salem value is 34!  That’s average speed.

I should point out this may be a last-minute screwup in modeling.  Our RPM (not always a stellar performer) still has just a baggy-looking low pressure trough with wind gusts maybe 30 mph…snooze.

ECMWF UPDATE 11:15 PM  Whoa!  The Euro just came in with the exact same track and strength. It’s even faster (good if you want strong wind) and forecasts 18 millibars pressure gradient late afternoon from Eugene to Olympia.  That’s significant windstorm material.  It also forecasts 50kt (around 60mph) wind gusts in the valley. ecmwf_windstorm  So all major models are showing the same thing right now…confidence is even higher.

I’ll be up early tomorrow morning before the OMSI meeting (at 10am sharp!) checking things out.

Chief Meteorologist Mark Nelsen


Longview Tornado

October 23, 2014

7pm Update:  NWS says it was an EF-1 tornado

MarkTornado_TodayInfo

It’s been a year and a half, but today it was time for another tornado in the FOX12 viewing area.  This time it was in downtown Longview!  Multiple videos we’ve been showing on-air and those you’ve probably seen on social media.  We’ll find out this evening what EF rating it will get; the NWS is up there right now doing a storm survey.  From the damage it appears to be similar to what hit Aumsville in December 2010, maybe a little weaker.  Here are the last 3 tornadoes we’ve seen in our area

MarkTornado_RecentNorthwest

MarkTornado_RecentNorthwest2

MarkTornado_RecentNorthwest3

Chief Meteorologist Mark Nelsen


Wettest Day in 2+ Years: Stormy Saturday Thoughts

October 22, 2014

11:20pm…

1.89″ of rain so far in Portland today, that’s our wettest calendar day since January 19th, 2012!

Luckily tomorrow we’ll see just frequent showers with sunbreaks mixed in.  Still wet, but not as gloomy.

I’ve been running way behind all night since I’ve been training a new employee and doing 3.5 hours of news from 8-11:30pm. Doesn’t leave much time for blogging!

I’ve checked out all the models for Saturday when there are hints of a surface low pressure system possibility shooting up the coastline and giving us a south wind of some sort.  The 12z GFS had shown a major windstorm for our area, but following runs are much weaker.  The 12z ECMWF was pretty windy. The 00z NAM and 00z GFS are splitty and weak, nothing to see with those runs.  The 00z Canadian is windy but nothing too crazy.  The new 00z ECMWF is noticeably weaker, but the low is doing almost exactly the same movement from SW to NE.  Here’s the 11am, 5pm, and 11pm Saturday.

ecmwf_slp_precip_nw_12

ecmwf_slp_precip_nw_13

ecmwf_slp_precip_nw_14

The storm moves quickly, from off Cape Blanco to Puget Sound in 12 hours!  But it weakens from around 983mb to 990 at the same time.  If you want a good windstorm you want a deepening low to move quickly.

The wind gust forecast shows 50+ kt gusts at 11pm over SW Washington. ecmwf_uv10g_nw_14  There is no image between 5pm and 11pm, but I think it’s safe to say the ECMWF would show 50 mph gusts over the Willamette Valley based on this.

I’m not real excited for now (yet), and I’m hoping for model solutions that are much closer tomorrow so we can make a coherent forecast without a bunch of words like “possible, could be, watching, not sure, undecided etc…”

I do like that the ECMWF has shown two runs with pretty consistent solutions.

Chief Meteorologist Mark Nelsen


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