February “Heat Wave” Coming…How Warm?

February 4, 2016

9pm Thursday…

You knew I just had to have a dramatic title like that didn’t you?

HIGHLIGHTS

Sunday through Tuesday, and possibly Wednesday will feature our first taste of “early spring” this year with some record high temperatures likely in spots.

  • Skies should be all or mainly sunny during that period
  • High temperatures away from the Gorge wind areas in the western valleys and in the Cascades should reach 58-64 Monday-Tuesday
  • Highs at the Coast and Cascade Foothills will be up around 70 in spots those two days

 

WHY?

It’s been obvious for the past few days that a big ridge of high pressure in the upper-atmosphere will build over the Pacific Northwest.  That starts this weekend and then continues through the middle of next week.  Models have been in excellent agreement with the general pattern.

MarkJet_Warm_ColdSeparated

Those models have also been in agreement that this will be an unusually to record warm airmass for early February.  Here’s the Salem 850mb temperature (5,000′ temp in C) climatology from the SPC website.

Sounding_Raw

I know; lots of lines.  The thin red lines show the warmest temperature ever recorded for every day of the year at 850mb.  Think of those lines as the warmest temperature recorded on any one date around the 5,000′ elevation.  Notice that from late January through all of March the 850mb temperature has never been up to +16.  Both the GFS and ECMWF models say that on Monday afternoon/evening the temperature over Salem will be around +16 to +17!  That would be a new record (if it occurs) for us.  I’ve highlighted what models are showing in yellow and you can see it in the maps below:

As a result, I’m confident we’ll see temperatures up to 60 or higher in the 3,000-5,000′ range over and west of the Cascade Crest on Mt. Hood Monday/Tuesday.  Not east of the crest and maybe not Government Camp either because of a cool surface high east of the mountains.  You can see it on the maps above.

But what about the lower elevations?

IF it was March with the same atmosphere overhead, we’d see temperatures in the 70s early next week in the lowlands.

IF it was mid-January, I’d expect highs around 45-50 degrees as a strong inversion locks in “cool” air in the valleys.

But we’re inbetween and that’s the temperature forecast problem.  Some sort of inversion will still be present but we’re right on the cusp of the end of inversion season so it’s tough to tell how much we’ll break out of it.  We’ll also have a good 6-8 millibars easterly wind flow through the Gorge, so the areas in the strong east wind zone here in the metro area will likely remain below 60 degrees.

Similar weather patterns in early February 1963 and 1995 DID produce highs into the mid 60s in the metro area so it is very possible we see a 65 degree high somewhere in the lowlands.  This evening’s WRF-GFS run from the UW shows highs Monday in the 60-65 degree range in our area and that’s pretty much what our 7 Day forecast shows.  Earlier this model had shown even warmer temps but this seems more reasonable now.

wa_tsfc.72.0000

Now these have all been just weather nerd details…the big picture shows lots of sunshine Sunday-Tuesday and very warm temperatures…Enjoy!

By the way, record highs at PDX are 62, 64, 62, 65 for Sunday-Wednesday.  We’ll see if we beat one or two of those.

Chief Meteorologist Mark Nelsen


ECMWF Monthly Run

February 4, 2016

Last night was another run of the ECMWF ensembles out to 32 days.  That takes us into the first week of March and it looks mild, or at least ridgy with no sign of stormy weather.  Winter is over if this theme continues.  Well, actually “winter was over around January 5th” will be more accurate if this is the case.  This 2nd half of winter should not be a surprise in a strong El Nino season.  Generally most action happens the first half of the wet season in these years…not always, but often.  For the past few runs I’ve noticed some sort of cool spell around the 20th (give or take a few days), but now on this run the ridge is a bit closer so that has disappeared.

Week1:

500za_week1_bg_NA

Week 2

500za_week2_bg_NA

Week 3

500za_week3_bg_NA

Week 4

500za_week4_bg_NA

The 12z ECMWF and GFS ensemble charts say the very warm weather coming next week will be followed by near average 850mb

temps beginning around Valentine’s Day.

tseries_850t_000-360_Portland

tseries_850t_000-384_Portland

 

More on the record warm temperatures coming early next week in a few hours…

Chief Meteorologist Mark Nelsen


El Nino Update

February 3, 2016

9pm Wednesday…

Just a quick (or maybe not so quick) update on how we’re doing with El Nino so far this winter.

Average temperatures across the USA in December/January:

dec_jan_temps

Much of the West has been warmer than normal, mainly the northern half;  Cooler than normal across much of the southern half of the West.  That is about what we would expect in a strong El Nino year with warmer than normal temps across the north due to more frequent ridging.  Yes, it’s been another mild winter, but nothing like the warmest ever we saw last year.

What about rain/snow?  I think we all know the answer; it’s been very wet.  150-200% of normal across NW Oregon and SW Washington.  Most areas along the West Coast except far southern California have been well above normal.  The interior is a bit more of a mixed bag.  What sticks out most is that extreme southern California has been relatively “dry”…only running about average.  One theory for the lack of strong systems way down there (as opposed to other strong El Ninos) is that the unusually wet jet stream has been pushed farther north this time around.  That possibly due to a shift in the warm water along the equator OR the warming climate.  Those are just guesses.  It seems to me we have seen more subtropical ridging near the West Coast than we would typically see in an El Nino winter, but I could be wrong…just an observation.  Of course we still have February/March to soak those areas down south, but there is no sign of a significant change in the next 10-15 days.

dec_janprecip

This is what I wrote back in the fall (and it’s still on the tab on the top of this page)

Capture

The drier part didn’t happen but the mild part did.  #2, #3, & #5 have worked out fine.  We never had a big regional flood, but plenty of localized flooding back in December.  We sure didn’t have an arctic blast either, that doesn’t surprise me.

It’s beginning to appear this wet season/winter is going to be remembered for a VERY wild December (through Jan 3rd) and that’s it.  The rest being mild/wet but quite boring.  That’s assuming we don’t have a total change coming up around mid-February of course.  Yesterday Cliff Mass had a great posting about El Nino (my inspiration)…more maps and charts here:

http://www.cliffmass.blogspot.com/2016/01/stop-el-nino-forecast-complaints.html

Okay, let’s talk Cascade snow too.  That seems to be working out quite well.  If you recall, EVERY El Nino since 1970 has brought below normal snow to Gov’t Camp (4,000′).  That’s continuing this year.  Govy has seen 109″ so far this season, 149″ is normal through the end of January.  Every month except December has been below average.  If average snow falls in February, March, & April, we’d still end up with 225″ for the season, below the 270″ average.  Here’s the chart for Govy with the SO FAR numbers in yellow..much better than last year!

GovtCamp_SoFar

Higher up, at Mt. Hood Meadows the season total is of course much higher…271″ so far. Below are the number SO FAR in yellow for them compared to Govy.  This winter seems to be a case of warmer storms keeping the best snow up high…that is what we thought might happen.  I don’t have the average numbers by month up at Meadows so I don’t know how they would end up with average snow from here on out.  Again…FAR better than last year!  And we’ve already passed up the bad El Nino years of 91-92 and 04-05.

SkiAreaSnow_SoFar

Chief Meteorologist Mark Nelsen


Groundhog Day: But What Does It Mean?

February 2, 2016

9pm Tuesday…

It’s that time of the year…Groundhog Day comes around each February 2nd and the media LOVES to see what the furry little rodent says in Pennsylvania.  The practice goes way back to Europe.  Here are two proverbs from England and Germany:

If Candlemas be fair and bright,
Winter has another flight.
If Candlemas brings clouds and rain,
Winter will not come again.

The badger peeps out of his hole on Candlemas Day and if he finds snow he walks abroad,
but if he sees the sun he draws back in his hole.

By the way, Candlemas Day (on or around February 2nd) is the halfway point between the Winter Solstice and Spring Equinox; 40 days after Christmas.  In the past it was sometimes considered the beginning of spring.  That seems a bit early.  But I have a feeling that was for daylight; it’s definitely the beginning of spring with respect to light.  The ancient Imbolc festival is similar, celebrating that midpoint.  You can read about these in GREAT detail on their Wikipedia pages.
But we have our own prognosticator here in Portland.  He’s called BMAC.

Brian_Hedgehog

Of course that’s Brian MacMillan’s shadow this morning (looks like Slender Man?).  Seems pretty clear cut to me; he sees his shadow and that means 6 more weeks of winter.  If the last 3 weeks were “winter”, that’s fine with me.  The last 20 days of January were very mild.

But wait a minute!  Velda the hedgehog at the Oregon Zoo didn’t see her shadow, according to the folks there.  So I smell a conspiracy once again.  Who can forget the fiasco back in 2012???  I have a feeling that the (very nice) marketing folks at the zoo would prefer that each February be labelled an “early spring”.  “Come on out and visit us!

Or am I just a bitter old weather guy?  Take a look at the pic today:

OregonZooScam

Hmmm, sure looks like a shadow on the keeper’s collar!  Now in the case of this year we can probably give them a bit of a break; take a look at the 10am satellite image:

Satellite_10am

Half of the metro area was totally sunny (east side) and areas west of I-5 were mainly cloudy.  So according to the proverbs I get this forecast for the next 6 weeks:

MarkGroundHogDay_BunchOfCrap

Good news, the western metro area is headed into spring.  But for those of you on the east side…winter continues.

MarkGroundHogDay_BunchOfCrap2

Wow, we’re going to have some tough daily forecasts aren’t we in the weeks ahead?

That was fun, but…

MOVING ON TO REALITY

No sign of winter in the next 10-14 days (through mid-February) since we’ll be mild and wet or mild and dry.  Snow levels will be mainly at/above 4,000′ over the next two weeks.  Models are all in excellent agreement on a short-lived (a week or less) very strong upper-level ridge Sunday-Wednesday next week along the West Coast.  500mb map from the GFS Monday AM:

gfs_namer_132_500_vort_ht

That’s the kind of ridge that gives us 90 degrees in May, or 70-75 degrees in March.  In mid-late February that’s a 65 degree day maker.  However, it’s still early February and strong easterly wind through the Gorge Monday-Wednesday will likely keep us below 60-62 degrees in the metro area.  That said, it’s a real tough call on February 8th-10th.  IF we break the inversion even a little, we’ve got some 60-65 degree days coming up early next week.  That’s FALSE SPRING weather.

For sure the Coast, Cascades, and Cascade foothills are going to be very warm next week.  Central Oregon too.  We will also see lots of sunshine Sunday through Wednesday in all areas with the dry offshore flow.

Chief Meteorologist Mark Nelsen


Friday Evening Update

January 29, 2016

11pm Friday…

Time for the weekend!  In this case it means showers, sunbreaks, and maybe some hail/thunder for Saturday.  Could be an active day…that after a slow January (post-snow).

We ran a story tonight saying Crater Lake NP had huge attendance last year.  A good chunk of that was due to the terrible snowpack that melted quickly.  Earlier Rim Drive opening = more people!

I checked the stats and indeed the snowpack numbers look good down there

MarkSnowpackMeadows_SkiArea

January has been an interesting month…one that started cold with some snow at the lower elevations, but then the 2nd half was extremely warm.  Most of the month we saw frequent, but weak, pacific systems moving onshore.  These were generally mild systems so the snowpack didn’t change much through the month.  As a result the percentage of normal has dropped a bit below average on Mt. Hood and the huge numbers to the south have decreased a bit.

nora_snowpack

Compare these numbers to one month ago:

MarkSnowpack_Oregon_PlusFacts

Still MUCH better than the disaster last year!  Note this graphic is from LAST YEAR…

MarkSnowpack_Oregon_PlusFacts

Looking ahead, we’ll see lowering snow levels over the weekend.  Sunday morning I could see it sticking down to around 1,500′ and down around 1,000′ Monday morning.  That said, it looks mainly dry Monday morning.  After that snow levels rise again so whatever we see in the lowlands Sunday and Monday should be “Conversational Snow”.  That means lots of us see snow showers or snow/rain mixed, but it doesn’t affect our daily lives.  But we tell friends about it and Tweet/Facebook it.

Have a great weekend!

Chief Meteorologist Mark Nelsen


ECMWF Monthly Run Maps

January 28, 2016

3pm Thursday…

Time for another run of the ECMWF out to 32 days.  This one says “winter is over” after the middle of next week.  Yes, I know I’m being dramatic but at least I didn’t put it in the headline for click-bait!

One map for each of the next 4 weeks showing average 500mb height among the 51 ensemble members along with departure from average for this time of the year.  The first week is a little misleading because we have a cold trough over us to start and then a ridge (NEXT weekend) so they average out to near normal.  Basically a change is occurring midway through the week.

500za_week1_bg_NA

Beyond that it’s saying we get ridging through much of February.  Remember, it’s just one extended run of one model, although the message is similar to what it was showing 3 days ago.  At first it’s a full-latitude ridging (dry in California too), then it morphs more into ridging up north and wetter south.

 

Speaking of next week…

With a colder airmass Sunday night and Monday a weak surface low is shown on the WRF-GFS moving down the coastline.  This can be a good setup for snow to very low elevations.  Someone at a business lunch today said they heard it was going to snow Sunday.  Not sure where that came from because we’d be lucky to get sticking snow below 2,000′ on Sunday.  The ECMWF doesn’t show the low and is drier; but it’s something to keep an eye on for Monday.

There is also the possibility of snow/ice in the Gorge the middle of next week IF moisture returns and IF easterly flow sets up.  Not a good possibility for now, but keeping an eye on it.

Chief Meteorologist Mark Nelsen


Have We Seen the Coldest Of Winter?

January 27, 2016

11pm Wednesday…

Whew, a busy day for the news folks.  That means not much focus on the weather despite record highs at Salem and Roseburg.

PLOT_Highs_ORWA

Here in Portland there was just enough easterly flow to keep us “cool” at 54 degrees…two degrees below the record for the date.  Note that the 47 degree low “today” (calendar day) is the warmest low temperature since early January.  We haven’t seen frost in almost 3 weeks here in the city either.  A very mild 2nd half of January for sure after a nice and chilly start!

That brings up the question people often ask me this time of year (when temps start to warm).  “Has the coldest weather of winter passed on by?“.  I think that’s quite possible this year.  First, we’ve dropped to 24 at PDX twice in late November.  Then and again in early January the colder suburbs dropped into the upper teens.  Compare that with the past few years:

MarkColdestNightLows_Yearly

If we only have a low of 24 that’ll be a bit on the warm side, although not too unusual.  Look at the low temperatures over the past 20 years.  The title refers to last winter, although it may end up being correct for this winter too.

MarkWinter_ColdestDay

Take a look at a neat graphic from Climate Matters, showing the average date of the coldest winter temperature

2016ColdestDays_CONUS

We already know our coldest winter temperatures are often in late December, but you can see here it tends to be later in the winter in the Eastern USA, especially in the northern areas.  That’s because widespread mid/late winter snow cover reflects the sunlight well over there.  A wide open path for arctic airmasses to move south over the snow-covered terrain doesn’t hurt either.

The last two big El Ninos featured mild January/February weather so I think it’s UNLIKELY we have anything colder than 24 in the next 5-6 weeks.  Of course we know it’s POSSIBLE this late, but it seems unlikely this year.

Chief Meteorologist Mark Nelsen

 


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