From Winter to Spring and Back Again

March 9, 2012

Meteorologist Melissa Frey’s Weather Discussion:

When the heat was turned on yesterday, there was no stopping it!  The high temperature in Eugene was 67 degrees!  That’s 12 degrees above average! The last time we hit 67 was 126 days ago on November 2nd.

It was also impressive that we got that warm after starting out at just 27 degrees, just one degree higher than the record low.

The ridge of high pressure that allowed for the warm sunny weather is now sliding east.  This opened the door to a weak cold front that will come in tonight.

We’ll see rain showers Friday night which will continue off an on Saturday.  This first storm isn’t all that impressive, but will set the stage for a long series of winter weather.

The next storm after this one moves in Saturday night/Sunday morning.  We’ll see rain, breezy conditions and cooler air ahead of this well developed cold front.  Also overhead, a long wave deep trough will pull down another round of arctic air, which will drop freezing levels to at least 2,000 feet Sunday and down to 1,500 feet Monday.

It doesn’t end there.  Cold air and soggy conditions will stick with us through Thursday.  A second cold front will move through Monday night and a third Wednesday.  The upper level flow at 500mb will rebound slightly Tuesday and Wednesday which will raise freezing levels, but only to about 4,000 feet. This means the passes will see good chances for snow Saturday night through Thursday.

Is looks like our La Nina winter is pulling though…but later than expected.

Have a great weekend,

Meteorologist Melissa Frey
Follow me on Facebook and Twitter.

Advertisements

Impressive Snow Totals For Late Season Storm

March 1, 2012

 

Some impressive snow totals for our (finally!) late season winter snow storm. Thinking the ski resorts will be rocking this weekend for sure!

~ Chief Meteorologist Justin Stapleton


February 25, 2012

Melissa Frey’s Forecast Discussion:

Temperatures dropped dramatically Friday night as a storm moved into western Oregon. Winds gusted to 68 mph in Lincoln City, over 60 mph in the Cascades and to 36 mph in Eugene.

Heavy rain in the valley turned to heavy snow at the passes.  Willamette Pass had 12 inches of snow on the Highway by 10 a.m!

The snow level lowered to about 500 feet early Saturday, allowing snow to accumulate throughout the Coast range and Cascade foothills, including McKenzie Bridge and Myrtle Creek. Although it didn’t stick for long, falling snow was reported all the way down to the valley floor.

So this is pretty much what we expected. The front is long gone now, but the cold air remains and a few lingering showers to go with it.  Sunday’s forecast is on track.  Temperatures are dropping quickly tonight and should get down into teh upper 20s before sunrise.

The freezing level will lower to around 500 feet early Sunday.  There will be limited showers at this point, but with temperatures below freezing overnight, the valley could see brief sticking snow with any isolated showers that move through.

During the day, temperatures will warm back into the mid 40s for the valley, so the precipitation will change back to a snow/rain mix.  Elevations above 1,000 feet will still see isolated snow showers during the day, but it won’t amount to much more than 3 inches, even at the highest elevations.

Monday we’ll dry out in between storms with a slight ridge of high pressure overhead, but then it’s going to pick right back up Tuesday.

The next storm to hit us is over the Aleutian Islands right now.  It doesn’t look to be quite as cold as this past storm, but close. Freezing levels will stay between 1,000 and 4,000 feet Tuesday through Saturday.  The snow will continue to pile up in the Cascades and Coast Range, with rain showers in the valley and along the coast.

Stay tuned this weekend for any updates.  If you see snow in your area let us know via Facebook, Twitter, KEZI.com or e-mail.

Meteorologist Melissa Frey
Check me out on Facebook or Twitter!


Winter Weather Returns this Weekend

February 24, 2012

Melissa Frey’s Forecast Discussion

High pressure is in full force over the Pacific Northwest.  The dry, sunny, warm afternoon yesterday turned into a dry, clear, cold night! Temperatures dropped to 28° by 6 a.m.  We won’t stay cold all day though, in fact we should get all the way up to about 55°.

This high pressure area is going to slide east today, and behind it is a very cold storm that will drop down from the northern Gulf of Alaska.

The front will first bring rain to the Coast mid afternoon, then to the Valley between 5 and 7 p.m.  That precipitation will then make it up into the Cascades first as rain, then as snow. A very cold air mass will move in behind the front, dropping the freezing level from 5,500 feet to 2,500 feet by Saturday morning and 1,500 feet Saturday afternoon.  This storm will also bring in strong winds, especially for the Cacades and Central Oregon.  Gusts could get as high as 60 mph.

Here’s a break down of snow totals expected by elevation for Saturday:

Passes: 7­-15″

Foothills near 2,000′: 4­-8″

Below 1,500′: Rain

The heaviest precipitation will be overnight Friday, but as the center
of the low pressure area moves through, showers will continue Saturday
and Sunday.

For elevations above 1,000 feet, this means light sticking snow
is possible Saturday night through Sunday night and the valley floor could see periods of falling snow Sunday morning and snow/rain mix during isolated showers Sunday.  For a list of elevations in western Oregon click here.

Monday we’ll dry out in between storms, but then it’s going to pick right back up Tuesday.  Freezing levels will stay between 1,000 and 3,000 feet Tuesday through Thursday.  The snow will continue to pile up in the Cascades and Coast Range, with rain showers in the valley and along the coast.

Stay tuned this weekend for any updates.  If you see snow in your area let us know via Facebook, Twitter, KEZI.com or e-mail.

Have a great rest of your Friday!


Mild Weather Continues For Now, But Winter’s Not Over Just Yet

February 21, 2012

Melissa Frey’s Forecast Discussion:

Temperatures only dropped to 49 degrees in Eugene last night!  We had a nice surge of warm air from the west behind yesterday’s warm front and clouds overnight to keep it here.

A ridge of high pressure is parked just off shore and is continuing to rotate in small storms.  It’s sort of like a ferris wheel: clockwise flow around the high pressure picks up storms in the pacific and drops them into western Washington and Oregon.

Another warm front is moving through today, keeping our temps mild this afternoon (mid 50s), clouds overhead and light rain showers for the day.

This warm air is also being felt in the Cascades.  The freezing level will climb to 7,500 feet this afternoon, spreading rain all the way up to the passes.  The National Weather Center has issued an Avalanche Warning for the north Oregon Cascades and Washington Cascades.

Another storm will follow that same path early Wednesday.  This one is a bit larger and brings better chances for rain for the coast and valley.  Freezing levels below the passes behind this storm, so it’ll be back to snow for the ski resorts.

That ridge will slide east Thursday and Friday, which will move us from the north side of the ridge to south side of the ridge.  This means dry, partly sunny skies are on tap for Thursday and Friday morning.

The models are waffling on the details for this weekend.  All indications are that we’ll see another round of winter weather Saturday and Sunday as a cold area of low pressure moves in from the northwest.

Questions still remain though on how cold the air will get and how much moisture will be available.

Chances are good for heavy snow in mountains above 2,000 feet.  We could also see light accumulations between 1,000 and 2,000 feet and a few flurries to the valley floor Sunday.  Stay tuned as we continue to refine this forecast over the coming days!


Winter’s Last Gasp?

February 17, 2012

So if you hear the buzz around town, it goes something like this: “Is that all?”  They’re of course talking about our rather mild La Nina winter/non-winter of 2011-2012.  So far we’ve had just a handful (even less than that in the valley) of winter events. Mountains are starting to get back the snow lost in December but still no arctic cold snap acr0ss the state. Most of us think of an “arctic blast” as highs struggling to get into the 30s, and lows maybe in the low teens in the valley, well below zero in the mountains and Central Oregon.

 

So far this winter (which I am calling from Nov. 2011- Current), we’ve only bottomed out into the teens once in Eugene, a low of 19 on Jan. 16th. The coldest afternoon so far has been back in December, when we saw a high of 34. That’s it. Nada more. A couple of mornings in the 20s, but very short lived. Most of the really cold time has been with an arctic high sitting north of us bringing cold, DRY Canadian air with no chance for some valley snow.

 

Now I’m a glass half-full guy. Always have been. Think it’s what keeps me sane in this business and honestly in life. There’s always a chance you just have to keep truckin’ along. SO- that said, here’s some potential, and it’s just that, potential for a nice late winter blast by next weekend.  Below is the GFS model for 1000-500 mb thickness value for Feb. 25, late Saturday afternoon:

 

So here’s what I’m looking at: 1) A cold upper low just to our northeast, 2) Counter-clockwise winds pulling in moisture off the ocean, 3) thickness values across Western Oregon between 522 dm and 526 dm. The general rule for freezing levels at 500 mb is the “540 line” or where the rain-snow change over line is, which we’ve talked about.  The thickness of the atmosphere tells you how cold the column of air is and thus how easy it is so to speak to pull refrigerated air close to the surface (with snow) because it’s more dense.

 

Now, this is still 8-9 days out and a LOT can change in that time, but it bears watching over the next week. If, and this is a big if, we can get those ingredients in place, we might just have a nice last hurrah for winter as we round into early spring. We’ll see …

 

~ Justin Stapleton

 


Quick Hit of Winter

February 13, 2012

Tomorrow brings a nice shot of winter back to much of the Northwest with an upper level low sliding across Oregon tomorrow afternoon and evening. Snow levels have been holding around 2000 feet tonight and should stay that way through tomorrow. Here’s a picture of the low at 500 mb at 10p Tue night.

 

 

Temps at 500 mb are between -34 C and -38 C which is pretty darn cold air! It’s very densely packed as well which could aid in bursting showers below it. In fact, here’s what the precip map looks like at this same time:

 

 

 

 

 

 

 

 

 

 

 

Some good looking showers bursting through the area at the same time as well. So here’s the thing: Heavy showers can pull the snow level lower than it currently “sits” at because as rain falls some of it evaporates (virga) while some of it hits the ground. The droplets that evaporate cool the air surrounding the drop as it “dries”. It’s a process called “Evaporative Cooling”. It takes a lot of heat to evaporate water and so when drops evaporate they use up the heat in the surrounding space between drops which cools that tiny parcel of air. Well, if you’re drying millions of water droplets in a small space (relatively), you’ll cool the overall temperature of that air. That’s how when we have very cold systems in the winter here in Oregon, we can see rain showers mix some wet snow flakes in with the rain, especially when the rain really intensifies.

 

So do we see snow below 2000 feet? Likely, but it’ll be very brief, maybe down to 1500-1000 feet and much of that in the higher hills around the valley won’t stick. But just to peek, here’s the snow output for that same time:

 

 

 

 

 

 

 

 

 

 

 

 

Looks like some nice snow showers for folks in Vida, Blue River, maybe even a light inch or so near Oakridge. Passes should see 2-5″ when it’s all said and done too. Here on the valley floor, we’ll just be cold and damp Wednesday morning, but with lows likely near 29-30 degrees, slick and frosty as well.

 

~ Justin Stapleton

Follow me on Facebook!