Who is sticking the Ullr voodoo doll with pins??

Well, now, CAN IT BE? After the not so great bit of wet rain/snow coming this weekend through early next week there are inklings of a change back to a somewhat similar pattern to late December here. We can only hope!

Hopefully Gary is right.........I'm prayin' he is. That would be worth the wait.

Hopefully Gary is right.........I'm prayin' he is. That would be worth the wait.

Well, now. Here it is two days later and it doesn't look as favorable. Better than the last ten days, but the low pressure centers dropping south along the coast may end up being a little too far offshore for a lot of precip. Apparently, though, the GFS that I looked at is the least favorable of the models. This from the NWS forecast yesterday. From today, Sunday, NWS: This is the way it copies, not the way it reads on the NWS page under forecast discussion text: (Read just the CAPS)

.LONG TERM...PREVIOUS DISCUSSION FOLLOWS...THE LATE WEEK UPPER LOW 
  OVER THE ERNERN
Eastern
Click for More... PACPAC
Pacific
Click for More... WILL REMAIN IN PLACE ON THU AND TRY TO KICK OUT 
  ACROSS WRNWRN
Western
Click for More... WA ON FRI. WILL MAINTAIN ABOVE CLIMOCLIMO
Climatology/Climatological
Click for More... POPSPOPS
Probability of Precipitation
Click for More... FOR THU AND 
  FRI. ONCE THE SYSTEM KICKS OUT...YET ANOTHER UPPER TROUGHTROUGH
An elongated area of relatively low
atmospheric pressure, usually not
associated with a closed
circulation, and thus used to
distinguish from a closed low. The
opposite of ridge.
Click for More... WILL CARVE 
  ITSELF OUT OVER THE ERNERN
Eastern
Click for More... PACPAC
Pacific
Click for More......THIS TIME A LITTLE FURTHER WEST NEAR 
  140W. THIS COULD RESULT IN A BRIEF PERIOD OF UPPER RIDGING FOR WRNWRN
Western
Click for More... 
  WA ON SATSAT
1.Satellite (imagery) 2.Saturday
Click for More.... THE 12Z ECMWFECMWF
European Center for Medium-Range
Weather Forecasts. Operational
references in forecast discussions
typically refer to the ECMWF's
medium-range numerical forecast
model, which runs out to 10 days.
Click for More... ALSO POINTS TOWARD DRIER WEATHER NEXT 
  SATURDAY. FOR NOW...HAVE LOWERED POPSPOPS
Probability of Precipitation
Click for More... INTO THE CHANCE CATEGORY 
  (20-50 PERCENT) FOR SATURDAY...BUT SOME CONTINUED MODEL RUN-TO-RUN 
  INCONSISTENCY PRECLUDES REMOVING POPSPOPS
Probability of Precipitation
Click for More... ALTOGETHER. THE NEXT UPPER 
  TROUGHTROUGH
An elongated area of relatively low
atmospheric pressure, usually not
associated with a closed
circulation, and thus used to
distinguish from a closed low. The
opposite of ridge.
Click for More... STARTS AN EASTWARD RUN ON SUNDAY WITH A WETTER PERIOD 
  RETURNING LATE NEXT WEEKEND.  HANER

Gary. could you translate that into something a non-specialist can get their brain around? Telemetery from last night shows some light drizzle, but no snow!

Gary. could you translate that into something a non-specialist can get their brain around?  Telemetery from last night shows some light drizzle, but no snow!

For the short term forecasts, NWAC does a very good job. The longer term stuff - more than a few days- they don't really deal with. The best thing is to just get used to reading both NWAC terminology and also the forecast discussion text on the NWS page. The text at the NWS is now embedded with definitions for the shorthand that they use to make it easier to understand for us Dweebs. That must be why my copied text from the NWS came out so weird. Even then, the forecasters can't often give much more than 3-4 days because of uncertainty in the models. Model forecasts are also available on the NWS home page and others are in different locations on the web. There are a number of forecasting models. The 10 day GFSX is available at the UNISYS site under GFSX. But the longer term GFSX (greater than 5 days or so has been consistently forecasting a far better winter than we've been getting all winter long. Maybe it doesn't deal well with the sort of odd patterns that have dominated most of the winter.

There is something called "Spaghetti Plots" that run a model and then change base conditions to see what happens to the model outputs with those different conditions. It is often the case that the Spaghetti Plots diverge (i.e. become useless) beyond a few days. Garth mentions in today's Avy Weather forecast that there is a lot of uncertainty beyond Wednesday in the present scenario.

One thing that has worked for me over the years for longer forecasts is persistence - i.e. what ever is going on today if it has been a repeating pattern will continue to do so....until it doesn't. Some patterns repeat with only minor variation for fairly long periods of time. I guess the way I look at it is there must be some meteorological reasons for the patterns to be somewhat consistent - I don't really care what those reasons are - they are beyond me - but that doesn't make much difference anyway because all I really care about is what is going on, not why.

For instance, last winter was a great winter but towards March or so the Low pressure centers off the coast kind of started dieing off just off the NW coast. Well that same pattern reappeared (after a summer respite) in latter August, September, and very early October. Then high pressure took over and essentially lasted (with a brief Pineapple Express being the only significant anomaly) until mid December. All that really changed in that period is that the high just kept getting stronger. Then the high remained strong but retrograded (moved westward to the East Central Pacific) and for three weeks we were benefitted by troughs forming in the eastern Gulf of Alaska and then driving south on the back side of the high along the coast. However, each trough was a little more maritime and warmer than the one that preceded it. Eventually, that all ended with a couple of more Pineapple Expresses and then, voile, the high pressure returned for essentially all of January.

More recently split flows where the main trough moves south too far off our coast and then into California while a weak northern remnant has gone into the Anchorage to Juneau area has been the norm. And now we are changing again. Hopefully, we don't develop a strong split flow again and also we need the low pressure areas dropping south along the coast to stay close enough to us to give us significant snowfall (which really is the same thing).

What has been really odd about this entire winter has been the tendency for a strong ridge of high pressure to redevelop and also that the flow has been Meridinal (North-South or South- North) instead of zonal (across the Pacific). Zonal flow, which is common most winters, has only happened for a short period of a few days at the end of December's snowfall, 

Science: Cliff Mass: Secrets of Northwest Weather Prediction
Where Great Hall, enter on 8th Avenue
Calendar Town Hall Seattle » Science
Notes

Cliff Mass, professor of atmospheric sciences at the University of Washington and weekly guest of KUOW radio, is the preeminent authority on Northwest weather. In his new book, The Weather of the…
When

Wednesday, February 25, 2009, 7:30 – 9pm PST