December 2015 in the Pacific Northwest

[Deweydog]

As long as you're excited about it, we know something is going to happen.

Trackability and excitement are unfortunately not directly proportional. I'll keep you posted though!

[Deweydog]

And it snowing again.

That cool.

[SilverFallsAndrew]

Salem reporting light rain on the hour. Looks like silver falls is 31 right now.

 

At sea tac currently. The tarmac is wet. Nice view of Rainer in the moonlight coming in.

[Front Ranger]

Trackability and excitement are unfortunately not directly proportional. I'll keep you posted though!

 

I was told I built too much excitement up due to my tracking. Go figure.

[TT-SEA]

Some stout offshore flow shown in a week... and I assume there will be a well established cold pool over the basin.

 

http://mag.ncep.noaa.gov/data/gfs/00/gfs_namer_168_precip_p03.gif

[MossMan]

Some stout offshore flow shown in a week... and I assume there will be a well established cold pool over the basin.

 

http://mag.ncep.noaa.gov/data/gfs/00/gfs_namer_168_precip_p03.gif

Would that mean cold temps for us, or just certain areas?

[TT-SEA]

Would that mean cold temps for us, or just certain areas?

 

 

Well... we have an 850mb temp of +9C on that run at that time while Moses Lake is at -3C.  

 

Seems like an inversion for places sheltered from the wind.   And a raging east wind for me with temps in the 40s.

[MossMan]

Well... we have an 850mb temp of +9C on that run at that time while Moses Lake is at -3C.

 

Seems like an inversion for places sheltered from the wind. And a raging east wind for me with temps in the 40s.

Inversion cold I meant, not real cold. Thanks for the info, the ground could use a break. The lake house dock is now under water...first time I have seen that!

[Deweydog]

I was told I built too much excitement up due to my tracking. Go figure.

You got a little creative. It's okay to be a little exuberant, even if you sacrifice a little objectivity and analytical worthiness. It is the holidays after all...

[Front Ranger]

You got a little creative. It's okay to be a little exuberant, even if you sacrifice a little objectivity and analytical worthiness. It is the holidays after all...

 

Nah, I just said if the pattern was a bit different it could result in widespread lowland snowfall. Like 7 days out. Nothing crazy or all that exuberant. I apologize if that statement caused anyone to pee their pants or have a crappy Christmas.

[Deweydog]

Nah, I just said if the pattern was a bit different it could result in widespread lowland snowfall. Like 7 days out. Nothing crazy or all that exuberant. I apologize if that statement caused anyone to pee their pants or have a crappy Christmas.

Sometimes peeing your pants is the indication a great Christmas.

[TT-SEA]

Inversion cold I meant, not real cold. Thanks for the info, the ground could use a break. The lake house dock is now under water...first time I have seen that!

2015... the year of drought and wildfires and also record rain and flooding. Yet statistically not too far from normal for precip.

 

Looking forward to the first actual dry day of the month tomorrow. This wet period was perfectly timed to challenge December records since it started exactly at the beginning of the month.

 

Global warming argues for more warmth and more extreme drought and wet patterns. This year fits that mold.

[TT-SEA]

Our coveted Jan 1-10 period is looking pretty shaky right now.   We are edging towards Mark Nelsen's 'stick a fork in winter' proclamation.     

 

With hindsight next April... Christmas Day might end up being the day it should have been made.   We will see.   Sort of feeling like it with the strong Nino in place and nothing on the horizon at all in the models.

[Deweydog]

Crazy strong gorge gradients later next week. Rob may start model countdown and such just for that.

[luvssnow_spokane]

Well, at least we can say our weather has not been boring this fall/winter season... What else can we ask for in the PNW?

[luvssnow_spokane]

Crazy strong gorge gradients later next week. Rob may start model countdown and such just for that.

Gripping!

[Deweydog]

Gripping!

Good point!

[luvssnow_spokane]

Good point!

Just keeping it objective and following your enthusiasm.

[Deweydog]

The Canadian is pretty hard freezy...

[MikeInEverett]

Today was probably just the 2nd or 3rd time this month I've seen the sun.

[MR.SNOWMIZER]

Be nice to get a few inches Sunday and maybe more Tuesday before the ridge pattern starts. Could have snow on ground for a bit.

[TT-SEA]

Extremes on each side of the mountains in a week:

 

http://www.atmos.washington.edu/mm5rt/data/current_extended/images_d2/slp.168.0000.gif

[GHweatherChris]

Extremes on each side of the mountains in a week:

 

http://www.atmos.washington.edu/mm5rt/data/current_extended/images_d2/slp.168.0000.gif

Offshore flow FTW.

[whitechristmas]

Our coveted Jan 1-10 period is looking pretty shaky right now.   We are edging towards Mark Nelsen's 'stick a fork in winter' proclamation.     

 

With hindsight next April... Christmas Day might end up being the day it should have been made.   We will see.   Sort of feeling like it with the strong Nino in place and nothing on the horizon at all in the models.

 

Winter started 3 days a go and Mark's stick-a-fork-in-it graphic never appeared until 2/17/15. Please don't rush the lowlander's winter season. We wait a long time for it, snow or no snow. Thanks and Merry Christmas!

[MossMan]

The Canadian is pretty hard freezy...

For when???? And ?

[MossMan]

Be nice to get a few inches Sunday and maybe more Tuesday before the ridge pattern starts. Could have snow on ground for a bit.

How did the 0z's look for potential on Sunday and Tuesday?

[MossMan]

I see NWS Seattle mentions precip possibly starting as snow on Sunday, especially east side and NW Interior. Perhaps Matt's baby will have a little kick to it!

Anyway just got home, foggy and 33 degrees.

[Phil]

Our coveted Jan 1-10 period is looking pretty shaky right now. We are edging towards Mark Nelsen's 'stick a fork in winter' proclamation.

 

With hindsight next April... Christmas Day might end up being the day it should have been made. We will see. Sort of feeling like it with the strong Nino in place and nothing on the horizon at all in the models.

Yeah, that window has effectively closed thanks to unfavorable wave conduit over the last two weeks. Ironically, those NPAC height rises are largely to blame.

[HighlandExperience]

[luvssnow_spokane]

[Perturbed Member]

00z WRF still sticking to snow for PDX Sunday AM:

 

http://www.atmos.washington.edu/mm5rt/data/current_gfs/images_d3/kpdx.42.0000.snd.gif

 

Basically whole column 32F or below.

 

 

http://www.atmos.washington.edu/mm5rt/data/2015122600/images_d3/or_snow24.60.0000.gif

 

 

The 00z Euro snow maps also show snow but looks like T-2 inches, less than what the previous euro runs showed. Temps continue to be very borderline.

 

Surface temp difference between operational GFS and WRF is quite significant for this event, the GFS is way too warm for snow but the WRF soundings indicate a decent low level layer of cold and dry air before the precip arrives. I am inclined to lean towards the higher resolution WRF for details like this.

 

http://www.atmos.washington.edu/mm5rt/data/current_gfs/images_d3/kpdx.39.0000.snd.gif

[Gradient Keeper]

00z WRF still sticking to snow for PDX Sunday AM:

 

http://www.atmos.washington.edu/mm5rt/data/current_gfs/images_d3/kpdx.42.0000.snd.gif

 

Basically whole column 32F or below.

 

 

http://www.atmos.washington.edu/mm5rt/data/2015122600/images_d3/or_snow24.60.0000.gif

 

 

The 00z Euro snow maps also show snow but looks like T-2 inches, less than what the previous euro runs showed. Temps continue to be very borderline.

 

Surface temp difference between operational GFS and WRF is quite significant for this event, the GFS is way too warm for snow but the WRF soundings indicate a decent low level layer of cold and dry air before the precip arrives. I am inclined to lean towards the higher resolution WRF for details like this.

 

http://www.atmos.washington.edu/mm5rt/data/current_gfs/images_d3/kpdx.39.0000.snd.gif

Nice post, it'll be close... I'll post more in a second which in my opinion looks more promising.

[Gradient Keeper]

Crazy strong gorge gradients later next week. Rob may start model countdown and such just for that.

You know me too well. I am all over it and just fully analyzed the WRF. It looks potentially crazy east of I-205.

[Gradient Keeper]

I have somewhat encouraging and exciting news to bring you. It’s kind of like Santa’s big sack of toys, but not really…. I’m only posting the goodies. for Portland-Vancouver metro and the Gorge.

 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
317 AM PST SAT DEC 26 2015

 

THE NEXT SYSTEM IS POISED OFFSHORE ON THE INFRARED SATELLITE IMAGERY. WE SHOULD SEE SOME HIGHER CLOUDS SPREAD IN TODAY. THE MAIN FRONT COMES ONSHORE SUNDAY MORNING AND THROUGH THE AREA SUNDAY AFTERNOON. HOWEVER THE MODELS DO SHOW AN AREA OF PREFRONTAL SHOWERS THAT DEVELOP INLAND TONIGHT AND HAVE ADDED SOME LOW POPS FOR THAT.

 

QPF WITH THIS FRONT IS MODEST…AND EXPECT SNOW AMOUNTS IN THE CASCADES AND THE COASTAL MOUNTAINS AND CASCADE FOOTHILLS WILL GENERALLY STAY BELOW ADVISORY THRESHOLDS. HOWEVER…WITH ANOTHER COLD NIGHT TONIGHT…THE INLAND VALLEYS WILL START OUT QUITE COLD SUNDAY MORNING…SO THERE COULD BE SOME SNOW IN THE MORNING AND EARLY AFTERNOON TO RATHER LOW ELEVATIONS ESPECIALLY NORTH OF SALEM. INCREASING EAST WINDS THROUGH THE GORGE WILL CONTRIBUTE TO THE LOWER SNOW LEVELS AS WELL… INCLUDING IN THE GORGE AND THE UPPER HOOD RIVER VALLEY. ADVISORY THRESHOLD AMOUNTS IN THE NORTH VALLEY AREAS AND IN THE GORGE ARE ONLY AN INCH…SO WILL NEED TO MONITOR HOW THAT DEVELOPS.

THE UPPER TROUGH COMES ONSHORE SUNDAY NIGHT AND MONDAY WITH SOME SHOWERS CONTINUING…THOUGH NOT A LOT OF QPF. THAT MAY BE ENOUGH TO MIX UP THE CHANCE OF ANY LOW ELEVATION SNOW IN THE NORTH VALLEY AREAS BUT PROBABLY NOT IN THE GORGE. TOLLESON

 

.LONG TERM…MONDAY NIGHT THROUGH FRIDAY…ANOTHER SYSTEM IS FORECAST TO DROP IN FROM THE NORTHWEST EITHER TUESDAY OR TUESDAY NIGHT. THE ECMWF AND GEM MODELS ARE FASTEST…THE GFS MODEL IS SLOWEST. THIS TRAJECTORY AND THE BIT OF EASTERLY PREFRONTAL WIND SUGGESTS **SNOW LEVELS WILL AGAIN BE LOW ESPECIALLY IN THE NORTH AND IN THE GORGE. THE PRECIPITATION EASES WEDNESDAY ESPECIALLY ON THE ECMWF AND GEM MODELS…PERHAPS NOT UNTIL WEDNESDAY NIGHT ON THE GFS. HAVE USED A BLEND FOR NOW FOR TIMING OF BOTH THE ONSET AND THE ENDING OF THE PRECIPITATION. AFTER THAT…THE MODELS ARE INSISTENT THAT A STRONG UPPER RIDGE WILL BUILD INTO THE AREA BY THURSDAY… RESULTING IN DRY COOL OFFSHORE FLOW THROUGH NEXT WEEKEND…THOUGH FOG IS POSSIBLE AWAY FROM THE GORGE IN THE SOUTH VALLEY AND NORTH OF KELSO. TOLLESON

 

This to me seems very possible. It’s kind of a classic overrunning/transition event scenario. We have colder air now settling into the Columbia Basin with temps as of 4 AM in the upper teens to mid 20’s from roughly Hermiston northward. It’s even colder further north. With high pressure sliding inland the cold pool is developing. Lots of stratus/fog is an indicator of this also. PDX-DLS is now switching offshore and east winds will develop later this morning. That will pull the colder/drier air westward through the Gorge. My hunch is like usual models are trying to weaken offshore gradients too quickly late Sunday into Monday. We’ll need things to come together just right(huge surprise), but this definitely isn’t impossible especially late December where it doesn’t take a whole lot to give PDX snow/wintry weather.

 

The 00z WRF 4km sounding was really close to a snow profile, if even briefly. 00z runs tonight will pinpoint things better. The other thing to watch for late this week towards New Years is the strong east wind. WRF suggests east wind increases today peaking Sunday morning-afternoon, then it redevelops this Tuesday and peaks Thursday night – next Saturday maybe longer. A very strong PDX-DLS gradient is shown. With the building inversion/warming 850mb temps and a 1040+mb high over the Columbia Basin this screams east wind storm, possibly damaging east of I-205. This also looks like quite a prolonged period of chilly/cold east winds. I can’t tell you how many times we’ve seen this in past Winters and that models do not handle these patterns well or play “catch up” to things as time progresses. I have high confidence this will play out too

 

6z GFS Ensembles - Portland

http://www.wetterzentrale.de/pics/MT8_Portland_Oregon_USA_ens.png

Trending a bit colder through New Years eve. Mean temp dips to -5c and note although precip looks rather meager, when it does occur 850s are -0c or colder. This suggests the east wind will pull enough cold air westward keeping the cold layer just thick enough over PDX for the potential of some kind of Wintry weather Sunday until roughly New Years Eve. Obviously a few wild cards and uncertainties such as moisture, 925mb temps in real-time, and surface flow are crucial. Seems promising to me nonetheless. You can also see the mean temp on New Years Day, Friday rising up towards +8c with a several members suggesting up to +10c. This gives more support for the coming big east winds(in my opinion) If we see 850s at +10c or > it could be crazy. Plenty of time to monitor these things.

[Tyler Mode]

Today marks 20 years since I began taking weather observations! My dad and family helps with that station now since I've moved out.

Since I've bought my own home in BG, it's been 5 years.

[Tyler Mode]

33.4, sadly my second coldest reading of the month...

[Gradient Keeper]

Wow. Yakima is down to 3 degrees now. Snowcover is awesome. This cold pool has a chance to get real strong in my estimation. Ephrata-Wenatchee-Moses Lake-Pasco-Pendleton could turn VERY cold overnight into Sunday AM. That's great for us since it will be funneling very cold east wind into PDX.

[MossMan]

Wow. Yakima is down to 3 degrees now. Snowcover is awesome. This cold pool has a chance to get real strong in my estimation. Ephrata-Wenatchee-Moses Lake-Pasco-Pendleton could turn VERY cold overnight into Sunday AM. That's great for us since it will be funneling very cold east wind into PDX.

Wish my area had a funnel from E. Wa. Anyway clouds have thickened up here with a temp of 31 degrees.

[TT-SEA]

Amazing morning...

 

 

[MossMan]