Surprise Snow!

January 31, 2006

Sticking snow fell around 2-3pm down to at least 1,100′ in the metro area this afternoon.  A classic example of "evaporative cooling".  A dry and cool airmass from the last storm leftover, then moisture from today’s system begins falling into that dry air.  The rain drops evaporate, which takes heat out of the air.  So the temperature falls.  Notice at PDX the temp fell from 47 to 40 from noon to 2pm.  Then as the atmosphere gets saturated we "bottom out".  So as of 4:30pm temps are beginning to rise again.  Snow threat is over and now it’s on to the heavy rain and strong south wind this evening.  Gusts to 40 mph are likely with or just ahead of the cold front passing through around midnight.

Another weak system Thursday, then a rainy one later Friday-Saturday.  What I’m really excited about is a big ridge forecast now by all models beginning Sunday-Monday and continuing through next week.  I can’t wait for the dry and sunny weather!


Endless Rain and Wankers Corner

January 30, 2006

Just like the perfect summer weather we get in July and August, it seems like our rainy weather does not want to stop.  A brief break this evening appears to be VERY brief.  Next plume of moisture is being pushed along by a fast Pacific Jet, much like a slug ready to pounce on it’s prey!  That seemed appropriate considering the satellite looper.

I don’t expect a recurrence of widespread flooding for 2 reasons:  First, snow levels only briefly rise to 5000′ Tuesday night, but are near 3000′ tomorrow and Wednesday.  That means minimal snowmelt to add to rivers.  And the period of heavy rain should be brief, confined to Tuesday PM through about midnight or so.  Maybe 2-3" in the Coast Range and up to 1" only in the Metro area.

Next weaker system moves through Wednesday night, then a stronger storm, but still not too wild for Friday PM-Saturday AM.  00z models say we MAY finally get ridging after that time for some February sunshine…Could it be?  I’ll believe it when I see it.  Remember 4-5 days ago we were forecasting drying at the end of this week.

Is there still time for a cold snap here?  Or snow in Portland?  Yes, but no sign of it in the maps.  3 weeks from now we’ll be done with the threat of severe cold.  And that leaves us with only about 3 weeks to get a snowstorm here in Portland too.  I give either of those a small chance of occurring, but who knows?

By the way, some viewers didn’t like my pronunciation of WAYN-KERS CORNER the other night while perusing the LIVE radar on-air.  Apparently it’s generally pronounced as WON-KERS CORNER, not WAYN-KERS (like yankers).  But I did find this link which seems to cast doubt as to who really knows:

http://en.wikipedia.org/wiki/Wankers_Corner,_Oregon

Either way, I apologize to anyone that thought I was being obscene.  It’s just that Wanker’s Corner near West Linn and Shorty’s Corner near Sandy are two of my favorite metro area places on the radar map…Mark


Still Looking Stormy

January 27, 2006

A double-whammy this weekend.  First system moving through now.  Nice strong jet stream support and plentiful moisture, plus not much of a warm sector with it.  That means lots of rain and ALL snow in the Cascades.  The strong westerly flow behind the storm Saturday is excellent for orographic lift into the mountains.

Sunday’s warm front (and eventually cold front by late Sunday night) is carrying subtropical moisture.  So another 2" of rain in Portland is quite possible Sunday-Monday.

By the way, Fairbanks had a high of -43 today and a low of -51.  Many of you have asked if that means the cold air will eventually move south into the Western U.S.A.  If the upper-level flow was forecast to allow this air to move south, of course it would get cold here.  But no models this evening support arctic air entering ANYWHERE in the continental U.S. in the next 7 days.

The wet pattern continues through at least the middle of next week too. Stay warm and dry this weekend…Mark


Another Stormy Weekend Ahead

January 26, 2006

A break this evening as cold & unstable air moves in behind today’s cold front.  Snow fell in the Coast Range down below 1000′ briefly this evening.  KPTV Tower temps up to 1900′ show temps remaining above 34 degrees, so snow probably won’t much below 2000′ overnight.

The long conveyor belt of subtropical moisture is poised to return to the Northwest this weekend.  A "cold" storm moves through Friday night/Saturday and then a very strong warm front/cold front couplet Saturday night-Sunday night.  The first may produce almost an inch of precip in the city, while the 2nd could easily be a 2" storm.  Keep in mind we’ve now had 8" in Portland so far this month.  We could be pushing 11" by the time January ends (Tuesday night).

Very cold weather in Alaska, but that’s mainly because the Jet Stream is depressed so far to the south in the North Pacific.  So the cold air just sits there and deepens.  No model shows that cold air moving south in the next 7 days, not even into the Central or Eastern U.S.  So our "La Nina" winter appears to continue…our wettest since the late 1990’s.


Cold Rain & Mountain Snow

January 25, 2006

Another indoor weekend coming up…

Looks like chilly rain through at least Saturday…good zonal (or westerly) flow runs right into the Northwest through the weekend.

I notice the snow level has dropped to around 2000′ or so this evening, and will lower slightly more overnight.  Unfortunately we won’t be adding to Portland’s impressive 1.2" winter snowfall total anytime soon since it’s not too cold.  Looking ahead through the next 3 days, 2 more weather systems move through.  Each is relatively cool.  I doubt the snow level climbs above 3000′ through at least early Sunday. 

Models show maybe 3" or so of precip in the next 84 hours (00z ETA) in the Cascades.  In this sort of pattern we might get 10" snow for every 1" of liquid rain, which means 2-3 feet of new snow is quite possible by mid weekend!  Wow…the happy days are here again old-timers…does 37 years old count?  If so I’m included as an old-timer now.

After that, warmer west-southwest flow may push snow levels up to 5000′ or higher, but overall it’ll be a stormy pattern through early week.

Long range GFS shows some sort of blocking or ridging starting late next week or so.  ECMWF doesn’t have much ridging and keeps us wet.


Nice While It Lasted

January 24, 2006

First, the most serious business of the day…sunny and warm!  58 at PDX today under mild easterly winds was the warmest since our Christmas Morning surprise wind.  Other than that day it was our warmest since mid-November.  Speaking of wind, the PDX-DLS gradient was quite a bit stronger than expected too.  Up around 9 millibars gave us 40 mph wind gusts in Troutdale and around 60 at the west end of the Gorge.  But it was a one day deal, it’ll be gone by Wednesday PM.

The sun/warmth was nice while it lasted…reminded me of those weeks of warm sun last February and early March.  But 2-3 days is the best we can do this winter.  All models show a change back into strong zonal flow by Thursday.  It continues for at least a week.  Long, Long range maps beyond that seem to be hinting at maybe some ridging, but that’s a long way off.

So the one thing really sticks out on the maps this evening?..Very Wet!  The rain coming up tomorrow and Thursday won’t be heavy at all, maybe .50" between the 2 days.  But GFS text output shows several inches of rain from Friday-Monday.  This could easily put us right back into flooding problems since I notice all the temporary "lakes" on the way to work haven’t dropped down at all.  Lots of water still stuck in the ground eh?

Add 3" to our 7.70" monthly rain so far and this will be our first 10" rainfall month at PDX in a long time!

Oh, and I did check for the daffodils today, couldn’t find them, but I live in a cooler spot at 1000′ so everything runs behind gardening-wise.


A Taste of Spring?

January 23, 2006

Alright, after a little detour to a ski area I’m back at work this week.  Sorry for the outage but I had no computer access the last half of last week.  I AM still alive.

Very nice day today wasn’t it?  Remember last January and February when this went on for weeks and weeks?  That’s not the case this winter.  Ridging tomorrow overhead (and moving off to the east) should push some light easterly winds down the Gorge and help us clear out for one last sunny day.

Then it’s back to the slop starting midday Wednesday or so.  Quite a westerly flow from Thursday-Monday of next week.  Looks pretty solid much of that time with maybe another 2" of rainfall.  That would put us up close to 10" for the month at PDX.

I HAVE noticed the ETA 12 & 00z text output shows the snow level below 1000′ Thursday, but I’ve also noticed in the past that it usually jumps up just a bit as we approach "the event".  So, chilly Thursday, but any snow showers stay above 1000′.

Looking ahead past next Monday?  I sure don’t see any chance for arctic air or low snow levels in the Northwest.  January will definitely go down as a very mild and wet month.  And at least the first few days of February look very mild too.

So are we done with the chance for a big arctic blast or PDX snow?  Not quite yet.  We still have about a 3 week window for cold weather here.  As I’ve mentioned before, we keep on guard until about mid February.   But the daffodils and tulips will be poking out of the ground soon!


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