Pacific Northwest Weather

[andrewr]

TT, do you think temps. will be cool enough next weekend and beyond to keep it snow above 3K feet? I'm not great at reading the models, but it looks as though it should be if I'm thinking right.

[TT-SEA]

It looks better but not great.

There will be periods of snow over the next three weeks in the mountains and it will be colder. But it looks like this blocking ridge over the western U.S. continues so periods of above freezing temperatures and rain at even 4,000 feet will occur.

So it will be hard to build up the snowpack.

March will be a different story. There will be some serious snow up there and the snowpack will attempt to get back to normal.

[~Brennan~]

TT that ridge you are showing next week IS WEAK... IT WILL BE CRUSHED... Don't you realize that?

[~Brennan~]

I bet you by tomorrow's 0z there won't even be that big of a ridge if any at all. It's about as weak as a ridge could possibly be already.

So you are saying according to records march should be a cold period... I think we have to wait and see what February ends up like first.

[TT-SEA]

Crushed??

Have you been paying attention to the pattern this year??

That is called a blocking high pressure. It has been a permanent fixture.

Many storms this year have died trying to "crush" this ridge. There are these blips where a system comes in (like this weekend)... but it just pops right back up.

Once we get towards real spring... there will be a massive shift in the global pattern and storms will roll into Washington again.

But probably not until March.

Have you been here this winter?? Its like you are just looking at the maps for the first time.

[andycottle]

Like Tim....I too have seen this big ridge of high pressure avertised on the GFS for the past 3, 4 days or so, that is for next week. In fact....looks like some pretty nice weather coming after this weekend that lasts Tuesday the 8th through the 11th of Friday evening. 500MB voricitys are 552 to 558DM during this time. Though 850MB temps still a tad cool and at around -3C to 0C. Upper level winds during the period appear in a somwhat southerly flow...which will aid in some mild temps at the surface. And by that I mean mid 50`s to maybe even lower 60`s. In the long range...or more specificaly from next weekend and onward, looks like a good zonal flow may try and set up shop over the PNW. If that holds, then we will be pretty wet at times with systems varying in strength that come on us ever other day or so. -- Andy

[~Brennan~]

Whatever TT we'll just have to wait and see. I bet that ridge you are counting on dies right before your eyes.

[~Brennan~]

One other factor that there is now that there wasn't earlier in the winter when we could squeak out a drop of snow or bust out an arctic blast is the cold air in Alaska... Back in January when we had the 2 week cool spell there wasn't cold air in AK, which happened to be a big factor, also, the east being under the influence of a ridge has a lot to do with it as well. If there is a strong SE ridge and a lot of cold air in Alaska, something is liable to happen. Not always, but it is very likely.

[TT-SEA]

One note... I am not "counting" on anything.

I am reporting what I believe will happen scientifically. If there was a big storm... that would be cool as well.

I just believe the blocking ridge will continue in one form or another for the rest of the month. More rain and maybe a little zonal but nothing too extreme. It won't always be sunny and dry... but the general pattern will be a western ridge and eastern trough.

You forecast what you WANT to happen. You are assuming I am do the same.

I am forecasting what I think will actually happen... what I want is irrelevant. Last time I checked... I did not control global weather patterns. And no matter how hard you try... neither can you.

I would love to hear you or Wizzard talk about a building ridge. I talk about storms and ridges. Because thats the nature of weather. You guys ignore all ridges and insist doomsday is right around the corner.

You would have said I was full of s**t if I told you the last half of January was going to be so warm and dry when the "1950 pattern" was developing back around January 6th.

You would have laughed me off this forum if I said R-Dub would be mowing his golf course and trees would be blooming in just three weeks.

You refuse to acknowledge all facets of weather... and therefore lose credibility.

If you ALWAYS forecast cold and snow... you WILL be right sometimes. Wizzard assumes that means he is superior to the professionals.

To have credibility... I need to hear you guys forecast and predict the warm spells AND the cold spells. Otherwise its just dumb luck.

[~Brennan~]

Actually I wouldn't have disagreed with you about the warm weather finishing out January... When we get a pineapple express it is a good sign that we will get an arctic blast about 10days to 3 weeks after. That would be characteristic of many of the bigger arctic blasts here in the PNW... Pineapple express/flood/ 2-3 weeks later arctic blast... I wasn't expecting anything for at least 10 days after the peak of the pineapple express... I didn't expect temps to get into the upper 50' and lower 60's but who did?

[~Brennan~]

So if this low tracks into southern washington this weekend, you still don't think we'll have lowland snow?

[TT-SEA]

Yes... it the low tracks into Southern Washington there is a chance of an inch or two of slush on Sunday morning before quickly melting. It does not look like that will happen though. And it will be around 35-38 degrees if it does... so no big deal at all. I believe the whole system will slip around us into Oregon with a mostly dry and cool Sunday.

Here is the 06Z run of the GFS to illustrate "blocking high pressure"

Next Thursday...



Monday (2/14)...



Saturday (2/19)...




It bends... then pop backs up. Over and over. Thats the pattern this winter. It will end in about one month. I do not believe it will be "crushed" next week.

[R-Dub]

Good morning everyone, looking outside I see WET ground! First time I've seen that for a while.
Current temp is 45 degrees.

Snipit from NCEP latest discussion..........
...WEST...

GUIDANCE DIFFS IN EXACTLY HOW TO HANDLE ENERGY WITHIN THE WRN TROF
EARLY NEXT WEEK BEGIN TO SHOW UP IN THE SHORT RANGE. THE 00 UTC
AND TO A LESSER EXTENT THE 06 UTC GFS RUNS SEEM ACCEPTABLE THRU
DAY 3 MON BUT THEN APPEARS TO FLATTEN THE TROF TOO MUCH. THE SAME
FOR THE DGEX. AN AMPLIFIED MEAN PATTERN SHOULD FAVOR THE ECMWF
WHICH MAINTAINS A STRONGER TROF AS IT DEPARTS FROM THE REGION DAY
4 TUE. THIS ALSO SEEMS BETTER SUPPORTED BY NCEP AND ECMWF
ENSEMBLES. AFTER THAT TIME...SOME WEAK ENERGY MAY FIND ITS WAY
INTO NRN/CNTRL AREAS WITH LOW CONFIDENCE OVER ITS FORM AND
EVOLUTION. AT THE VERY LEAST...THE CANADIAN SEEMS TO BRING TOO
MUCH ENERGY INTO THE WEST BY MIDWEEK. OP/ENS CONSENSUS AGREES
THAT SOME OF THIS ENERGY SHOULD INSTEAD CONTRIBUTE TO THE TROF/LOW
DEVELOPING OFF THE COAST OF CA/BAJA.

SCHICHTEL/RAUSCH


Well off to work.

[R-Dub]

Like I have said before, I have NO expetations for this weekend, and the white stuff in the lowlands........But anything can happen in this type of pattern.

Here is a snipit from latest NWS Seattle discussion............

AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SEATTLE WA 300 AM PST FRI FEB 4 2005

THERE IS AN OUTSIDE CHANCE OF SOME LOWLAND SNOW BY SUN MORNING AS LOW LEVEL FLOW WILL BE OFFSHORE AND TEMPERATURES WILL BE FAIRLY COOL. IT LOOKS MARGINAL AT BEST SO WILL KEEP THE SNOW WORD OUT OF THE FORECAST FOR NOW. DRIER NORTHERLY FLOW ALOFT WILL DEVELOP SUN AND CONTINUE INTO NEXT WEEK WITH LOW LEVEL OFFSHORE FLOW. THIS MEANS DRY WEATHER WITH SOME NIGHT AND MORNING FOG. SCHNEIDER &&

[TT-SEA]

Like yesterday... the new 12Z run of the ETA keeps all the action south the Seattle area after tonight. Maybe a quick shot of wet, slushy snow around Shelton but from Olympia north it should miss us completely.

Here is the 12-hour precipitation for the day on Sunday when the low comes ashore...

[andycottle]

Hi folks. Some pretty good rains this morning huh! Steady Rain should end by later this morning and turn to showers by about early afternoon. And if fourtune enough....maybe even a sunbreak here/there.

So anyhow... looking at today 6z and 12z GFS....it appears that we`ll still have a high pressure system over us for early next week. 6z wants to keep that high 8th - 10th, while the 12z keeps till the 11th and maybe even the 12th as it tries really hard to keep a 992MB low from sending rainy weather our way. And looks like that High gives out and allows some showers into our forecast area by 192hrs. During this time 500MB voricitys are around 546 to 552DM with 850MB temps still remaining a tad cool...0 to -3C. So here at the surface...am going to say we highs in the low-mid 50`s for next work week.

Now to get your interest here, and from about next weekend onward...we end up and having a zonal flow. But the problem is that the jet stream will be running in a dominating High over a large portion of the Western U.S/Rocky Mountain West area...which means the Northern branch heads WAY up north into the Alberta/ Saskatchewan areas and then takes a nose dive back down into the upper MidWest and portion of the lower Great Lakes area. The southern brach however stays well to out south, but in a zonal fashion and heads into Southern Cal and then across the lower cental plains and into SE U.S areas. So what does that mean us? It means that well see systems getting caught up in the split flow which also means that weather wont be all that strong when they com onshore to bring us showers.

So that is the weather update for right now. -- Andy

[Guest]

An inch or 2 of slush in the Seattle Area maybe, but what about other areas like the Kitsap or Bellingham or any outlying areas?

[Guest]

http://weather.unisys.com/ngm/48h/ngm_500_48h.gif

Just thought I'd show that

[AnthonyC]

Wow, it's amazing hour 24 hours can completely change weather. Today was a wild weather day up here in Everett. From heavy rain to hail, we experienced alot of winter-like precip.

To start, on my way to school this morning, it seemed like we were in the middle of a monsoon it was raining so heavily. We probably had rainfall rates of 1.5 inches an hour from about 7am to 9am. It was pretty amazing stuff...it hasn't rained that hard for a few years. Unfortunately, I was walking from the school parking lot to East Campus and got deluged by water...I was DRENCHED and stayed wet the entire day. That wasn't cool.

Then, when I was coming home from school around 1:30pm, it started raining hard again, but this time it briefly changed to hail. We got about an eighth of an inch before it stopped. A pretty decent-sized PSCZ formed right over Everett...as I'm typing it continues to rain.

But the big difference is the temperature...it's currently 41 F with light rain. It hasn't been this cool for almost three weeks. And the last time I checked, both Stevens Pass and Snoqualmie Pass were reporting moderate snow...Stevens Pass had 2 inches of new snow. Hopefully that's a sign of things to come.

As for Sunday morning, things look interesting. As of now, a surface low is expected to develop off the Vancouver Island coast and then quickly move south and east. But how far south and east will it move? Believe it or not, the GFS rapidly strengthens the low and has it move ashore over northern Washington...which would bring heavier precip but NO lowland snow...snow levels would stay above 2k. But the ETA brings the surface low into northern Oregon, bringing down colder air but keeping the moisture along the Olympics and southwest Interior. For now, I guess you can split the difference, but I'm leaning toward the ETA because it handles the terrain of the Pacific Northwest a little better.

In any event, expect a cool/unstable weather pattern until Monday, and then the trough over the Pacific Northwest will move east and a weak ridge will develop over the Central Pacific...something very typical of this entire winter. Some models want to break the ridge down pretty quickly and introduce a zonal flow by Thursday of next week, but I'm not sold on that solution...this amplified ridge has dominated our winter weather pattern all season long...no reason to believe it will change.

At least the mountains should get a good dose of snow this weekend and early next week...Stevens Pass could get well over two feet by the time everything winds down.

Anthony

[W13]

A very quiet weather day here, after a few morning rain showers that brought 0.03" of rain to the area. We have also had some light winds today, averaging about 6 mph in recent hours. Our wind gust for the day so far has been 25 mph.


As for this weekend, it is looking like it has potential. Looking at the latest models, the GFS has the low developing off of Vancouver Island and sweeping it down from the North, and then invading the rest of Western Washington and Northwestern Oregon. This is also what the latest 48 Hours NGM is showing, but it is showing a good amount of precip, I think even more so than the GFS. Here is the latest NGM for people to look at:



If that low just tracks a little bit more south, then we are in buisness. We will be getting significant Frazer Outflow at this time if this low does do that, and go into Northern Oregon.

The MRF on the other hand, is much slower in developing the low. It shows the low developing after 12z on Sunday, then brings the low in, kind of spread apart, to all of Western Washington and Oregon. If this were to happen Sunday Night (the low holding off until then and then sweeping in like that, then we could be talking about some snow there as well). Here is the MRF for 48h, 60h and 72h:







The AVN is quicker to bring in some light precip around Saturday afternoon. Then it rapidly strengthens the low and sweeps it more south than what the other models are displaying. Here is the latest AVN Models for the 36h, 48h and 60h:








Later tonight I will analyze the latest runs of the different models, and give my preliminary insight on what will go down Saturday evening/Sunday morning.