noise to signal

More icy weather coming. Imagine my delight.

Miz Becky pointed me to the charmingly chatty current NOA'A forecast discussion... It looks like she may get her dang 'ol snow, man, I tell you whut.

I've changed to much easier to read sentence case, and added emphasis:

Area forecast discussion Fxus66 ksew 051656 afdsew

area forecast discussion
national weather service seattle wa
900 am pst wed jan 5 2005

.synopsis...cool...dry northeast flow will continue today. A cold front will move south across the area thursday afternoon bringing rain and snow to the area. A cool upper level trough will develop offshore on friday keeping the threat of precipitation in the forecast through the weekend. A reinforcing shot of cold air from canada could invade western washington by early next week.

&&

.discussion...well the forecast is never simple when talking about snow in the low lands...and this case is no exception. Once again we have all the ingredients coming into play..ie cold/dry airmass in place...sfc high to the n...deepening sfc low near the coast...and moisture. How these come together will make all the difference between a mostly snow or mostly rain event. Dewpoints around wrn wa running in the upper teens to low 20s...with ne drainage wind still keeping a dry/cool air in place. The key will be how much of this cold dry air will remain in place as moisture begins streaming in on thu ahead of an an approaching canadian low. Models imply that sly flow develops enough to mix things out as precip begins thu afternoon. We may end up with precip beginning as snow then changing over to a mix or just rain. The exception will be whatcom county where gradients will remain offshore and should keep the colder air in place. Most mos guidance agrees suggesting the low level airmass will wet bulb to around freezing...ensuring mostly snow there. Newer models qpf amounts still running as high as a half inch suggesting warning amounts still possible in whatcom county thu night into fri. The watch will remain in effect at this time. As for areas south...the differences between the eta/gfs make it difficult to discern when a switch back to snow may occur. The problem will be that as colder air moves in both aloft and at the sfc later fri night into sat...the bulk of moisture could move swd. The gfs still lifts some sort of deformation/warm frontal boundary into the area with renewed precip. This could produce a more widespread low land snow...especially if dynamics and wet bulb effects are able to draw the snow level all the way down. Believe the current forecast is the best way to go for now indicating maybe an inch around puget sound thu night into fri. Will need to poor over the latest model data during the day and hope for some better indications either way on how this plays out.

The trough lingers near the coast for showers possibly continuing into sat and sun but a generally decreasing trend. Cold enough air should drain in by that point for mostly snow showers. A very brief dry period may set up late sun into mon before the next canadian low begins to migrate swd towards the area. This system is shown by virtually all global models to have a very strong arctic front associated with it. The front is expected to drive swd into wa during the day tue with much colder air and possibly bring a round of snow the area. Some long range models indicate this could be some of the coldest air in years possibly persisting through much of next week. H850 temps -20 to -25c suggest high temps not getting out of the 20s for highs...possibly even a near record cold event. This is still about 6 days out right now and models often over do the amount of cold air. Will plan on gradually trimming temps back in the extended for the afternoon package but stay conservative at this time. Stay tuned to the latest forecasts as an arctic blast is not out of the question next week. Mercer

Joy. At least I have my Patagonia silk-weight tights to keep my spirits up.