March 2017 Observations and Model Discussion for the Pacific Northwest

[umadbro]

Aberdeen is scoring I bet.

[bainbridgekid]

Aberdeen is scoring I bet.

Heavy sticking snow in Westport right on the Ocean.

 

http://www.westportcam.com/

[GHweatherChris]

Aberdeen is scoring I bet.

Not really, still only half inch even though iy has snowed all day, did hear from my mom in Westport yhat they had thundersnow just a bit ago. Its snowing heavily here currently, might get some more accumulation before its over.

[bainbridgekid]

Not really, still only half inch even though iy has snowed all day, did hear from my mom in Westport yhat they had thundersnow just a bit ago. Its snowing heavily here currently, might get some more accumulation before its over.

Sounds a lot like scoring for mid afternoon in March.

 

Looks like the heaviest snow has been just to your West so far.

[ShawniganLake]

Looks like some intense precipitation rates associated with the compact low coming ashore. Cloud tops have cooled rapidly in the trailing band. The afternoon heating might enhance the convection as it rolls ashore. It's going to be interesting to watch how it tracks.

Looking at the mesoscale models, I would assume a secondary low is about to form off of the SW corner of Vancouver island.

[FroYoBro]

A tiny little shower that just hit me gave me 5 minutes of a rain/snow/graupel mix. We just need more moisture! 

[SilverFallsAndrew]

18z GFS still showing a major snow event for W. Washington Thursday night into Friday morning. Perfect timing...

[Guest Dome Buster]

Snow level in the foothills last night was about 1300' in Northern Oregon.  At least as far as the Cascade foohills were concerned.  Snow on the ground all the way to Brightwood, patchy thereafter.  Then surprisingly a little more near the eastside of Sandy.

 

Just an FYI. 

 

Interested to see what this line of showers associated with the low coming onshore do in the next few hours.  Pretty thin down here though.

[Deweydog]

Breezy!

[SilverFallsAndrew]

18z GFS still showing a major snow event for W. Washington Thursday night into Friday morning. Perfect timing...

 

Then a secondary, but more minor snow event for W. Oregon Saturday night into Sunday. 

[Front Ranger]

This evening should be quite interesting in Western Washington with that low moving ashore. NWS is probably feeling squeamish after the bust last light, but this looks much more promising, IMO.

[Tenochtitlan]

Wow, the low is beautiful on radar loop. It almost reminds me of watching a tropical storm landfall.

[TT-SEA]

This evening should be quite interesting in Western Washington with that low moving ashore. NWS is probably feeling squeamish after the bust last light, but this looks much more promising, IMO.

 

 

Coming through fast though... and probably a little too early.

[VancouverIslandSouth]

Looking at the mesoscale models, I would assume a secondary low is about to form off of the SW corner of Vancouver island.

 

That could certainly make things interesting over the Southern Island this evening. It looks like the low reforms in the Olympic shadow. I've been watching the Juan de Fuca fill up with low clouds over the past few hours, surface pressure is now down to 997mb. EC is probably hesitant to pull the trigger and issue a snowfall warning after last night but I wouldn't be surprised if we end up getting more snow than there was last night, this has the appearance of an event that can produce more intense precipitation rates.

[TT-SEA]

Now:

 

 

 And by 6 p.m. its all over...

 

[Front Ranger]

Coming through fast though... and probably a little too early.

 

I think areas north of Seattle especially have a good shot at some decent accumulation. Precip probably won't really get going there until late in the day, and then good chance some sort of CZ forms after the low passes.

[TT-SEA]

I think areas north of Seattle especially have a good shot at some decent accumulation. Precip probably won't get really going there until late in the day, and then good chance some sort of CZ forms after the low passes.

 

No c-zone shown... low is moving NE so the flow behind it will be from the SW.    

 

More like a deformation zone moves north from Seattle up to Bellingham.  

[Front Ranger]

No c-zone shown... low is moving NE so the flow behind it will be from the SW.    

 

More like a deformation zone moves north from Seattle up to Bellingham.  

 

We'll see. That's assuming it gets pretty far north.

 

Also hard to say in these situations if it will maintain the same speed or not.

[SilverFallsAndrew]

The long range looks cold and unsettled. 

[TT-SEA]

We'll see. That's assuming it gets pretty far north.

 

Also hard to say in these situations if it will maintain the same speed or not.

 

 

Its cranking off to the NE and losing its definition.  

[Front Ranger]

Its cranking off to the NE and losing its definition.  

 

Yep, appears to be. Which may mean it will slow down. Hard to say.

[SilverFallsAndrew]

Now:

 

 

 And by 6 p.m. its all over...

 

 

At least down here, the "now" pic is about an hour or two off...

[TT-SEA]

Yep, appears to be. Which may mean it will slow down. Hard to say.

 

Its a late afternoon event for the Seattle area... if anything of significance even holds together.  

[TT-SEA]

At least down here, the "now" pic is about an hour or two off...

 

Yeah... 

 

[TT-SEA]

Also note the air is quite dry now in the Seattle area.    Which could be great with sustained precip... but will lessen the effects of a quick moving band.

 

SEA is now 45 with a dewpoint of 26 and precip is approaching.

[HighlandExperience]

Also note the air is quite dry now in the Seattle area. Which could be great with sustained precip... but will lessen the effects of a quick moving band.

 

SEA is now 45 with a dewpoint of 26 and precip is approaching.

That band is moving fast. Looks like a whip

[TT-SEA]

That band is moving fast. Looks like a whip

 

And the part heading our way is shrinking.  

 

Looks more robust farther to the south with the part heading towards Portland.

[Front Ranger]

Its a late afternoon event for the Seattle area... if anything of significance even holds together.  

 

Like I said, I like the chances for those north of Seattle.

[Jesse]

The long range looks cold and unsettled.

Just like my heart.

[TT-SEA]

Like I said, I like the chances for those north of Seattle.

 

Yeah... maybe Everett northward.   

[Dave]

I'm starting to like my chances of picking up an inch or two.  Would be a nice way to close out the winter.

 

http://www.tropicaltidbits.com/analysis/models/hrrr/2017030522/hrrr_ref_frzn_nwus_6.png

[FroYoBro]

I'm starting to like my chances of picking up an inch or two.  Would be a nice way to close out the winter.

 

http://www.tropicaltidbits.com/analysis/models/hrrr/2017030522/hrrr_ref_frzn_nwus_6.png

 

Good luck Frog King. 

[bainbridgekid]

I think areas north of Seattle especially have a good shot at some decent accumulation. Precip probably won't really get going there until late in the day, and then good chance some sort of CZ forms after the low passes.

I would expect most of the CZ action tonight to be up North of Everett around Mt. Vernon. Flow looks solidly SWerly.

[Front Ranger]

Looks like I wasn't off my rocker thinking there would probably be a CZ tonight north of Seattle.

 

The mesoscale models favor the development of a central Puget Sound convergence zone between
Arlington and south Snohomish County late tonight into Monday. The
18Z NAM hints at maybe 4 inches of snow in Lake Stevens by Monday
afternoon. The 18Z and 12Z GFS solutions have a different approach
taking the vorticity max associated with the upper low
northeastward then stall it between Mt Vernon, Bellingham and the
Lower Fraser Valley of extreme southwest British Columbia. This
solution results in the possibility of heavy snowfall
accumulations in the Bellingham area and lighter amounts if any
elsewhere in Western Washington. It appears that the prudent thing
to do at this point is to mention the low snow levels and the
potential for possible accumulations, then handle the issuance of
advisories in near real time as conditions evolve on radar and
the rapid refresh models.

[Front Ranger]

I would expect most of the CZ action tonight to be up North of Everett around Mt. Vernon. Flow looks solidly SWerly.

 

Sure, because the main low is still to the west.

[HighlandExperience]

Looks like I wasn't off my rocker thinking there would probably be a CZ tonight north of Seattle.

 

The mesoscale models favor the development of a central Puget Sound convergence zone between

Arlington and south Snohomish County late tonight into Monday. The

18Z NAM hints at maybe 4 inches of snow in Lake Stevens by Monday

afternoon. The 18Z and 12Z GFS solutions have a different approach

taking the vorticity max associated with the upper low

northeastward then stall it between Mt Vernon, Bellingham and the

Lower Fraser Valley of extreme southwest British Columbia. This

solution results in the possibility of heavy snowfall

accumulations in the Bellingham area and lighter amounts if any

elsewhere in Western Washington. It appears that the prudent thing

to do at this point is to mention the low snow levels and the

potential for possible accumulations, then handle the issuance of

advisories in near real time as conditions evolve on radar and

the rapid refresh models.

 

Hope it is wrong. I want the CZ right over King County. 

[Phil]

As of now, 850mb temperatures have dropped to -47C over the NW Canadian Arctic. That is the coldest on record over that domain at any time of the year, let alone March, since the satellite era began in 1979. It is also the coldest 850mb temperature analyzed at 850mb anywhere in Canada in at least 20 years, according to NOAA-ESRL, and given its forecasted persistence, may be the latest such occurrence in (recorded) history.

 

The EPS/GEFS suites both depict another round of increased mobile polar high production in late March as the PV breakdown/FW process continues, with many members suggestive of an additional of -40C/colder 850mb temperatures during that period, which might be unprecedented.

[MossMan]

Looks like I wasn't off my rocker thinking there would probably be a CZ tonight north of Seattle.

 

The mesoscale models favor the development of a central Puget Sound convergence zone between

Arlington and south Snohomish County late tonight into Monday. The

18Z NAM hints at maybe 4 inches of snow in Lake Stevens by Monday

afternoon. The 18Z and 12Z GFS solutions have a different approach

taking the vorticity max associated with the upper low

northeastward then stall it between Mt Vernon, Bellingham and the

Lower Fraser Valley of extreme southwest British Columbia. This

solution results in the possibility of heavy snowfall

accumulations in the Bellingham area and lighter amounts if any

elsewhere in Western Washington. It appears that the prudent thing

to do at this point is to mention the low snow levels and the

potential for possible accumulations, then handle the issuance of

advisories in near real time as conditions evolve on radar and

the rapid refresh models.

Hmmm sounds slightly interesting for my area!

[bainbridgekid]

Hmmm sounds slightly interesting for my area!

Tonight definitely looks pretty interesting up there.

 

Wouldn't surprise me at all if you picked up a couple inches of snow with a CZ.

[Tenochtitlan]

Looks like I wasn't off my rocker thinking there would probably be a CZ tonight north of Seattle.

 

The mesoscale models favor the development of a central Puget Sound convergence zone between

Arlington and south Snohomish County late tonight into Monday. The

18Z NAM hints at maybe 4 inches of snow in Lake Stevens by Monday

afternoon. The 18Z and 12Z GFS solutions have a different approach

taking the vorticity max associated with the upper low

northeastward then stall it between Mt Vernon, Bellingham and the

Lower Fraser Valley of extreme southwest British Columbia. This

solution results in the possibility of heavy snowfall

accumulations in the Bellingham area and lighter amounts if any

elsewhere in Western Washington. It appears that the prudent thing

to do at this point is to mention the low snow levels and the

potential for possible accumulations, then handle the issuance of

advisories in near real time as conditions evolve on radar and

the rapid refresh models.

Is this an either/or thing or is it possible for both a convergence zone to bring snow and a vort max to bring snow farther north?