Tuesday, January 17, 2012

Scaling Back

UPDATE TONIGHT AT 9 PM.  The 18 UTC model runs are consistent with the lesser snowfall totals of this morning's runs.

The latest series of model runs are in and to me they suggest we need to scale snow totals down over Puget Sound to 2-6 inches.  In other words, not a record even over the PS area..  Folks this is a very difficult forecast.  Everything depends on getting the track of the low exactly right...first to decide where the rain/snow changeover will be and secondly to get the amount of precipitation right.

Most of the models are in agreement that the low will go south of us...thus, more confidence that it will be pretty much all snow north of Olympia.  But having the low go south is a Faustian bargain...it reduces the intensities over us.   Right now it looks like 2-6 inches over Puget Sound (6 inches near Olympia, 2 inches near Everett) is the most consistent forecast with current model forecasts.  Tonight will will have a better idea.  As I mentioned before, a shift of a hundred miles or so for the low makes a huge difference on the forecast for us....a low that has developed over the past several days and over thousands of miles.  It is amazing we can even attempt to do this. 

Here is the latest 24-h snowfall totals ending 4 PM Wednesday.   Big gradient of snow up the Sound but LOTS of snow over the mountains and SW Washington, before it turns to rain there.


If the predicted path or intensity of the incoming system changes, this forecast will change.  It is sort of like aiming a rifle...you gyrate around until you lock on.  The storm shifts 100 miles north...ST headline could be true.

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