Storm Details Uncertain

October 20, 2010
4:34 P.M.

The details on the storms this weekend are still very, very murky. The American models, the GFS and the NAM, have been forecasting a large low pressure system to bottom out in the Gulf of Alaska at around 950 millibars, sending a strong front right into our area. This is a very deep low, but, surprisingly, these type of events are not all that uncommon where sub-950 millibar lows intensify until they kind of stall in the Gulf of Alaska. Here is a picture of the mm5-GFS model for 5 P.M. Saturday.



It is pretty similar to what we have been seeing all along. The coast has the best chance at getting high winds with this storm, and I wouldn't be surprised to see a stray 70 mile per hour gust, especially at Tattoosh Island. Gusts inland will be in the 30-40 mile per hour range. 

Now, let's look at the Canadian model, which is showing a scenario that would give us some wind. This model takes that one big storms and splits it into two smaller storms, but they come right at us. The same sounds true with the Euro, although since I'm not in the NWS I don't really have good access to that model. Here is the 00UTC Monday map (around 4 P.M. local time I think)

As you can see there is a powerful 965 mb cyclone slamming right into us. That would give us high winds. The latest GFS also *kind of* follows this, though the storm is further north and it kind of fizzles out before hitting us, stll giving us lots of rain and wind but not windstorm-type winds. One thing is for sure - the Cascades above 4000 feet will get a LOT of snow from this storm, and I think Snoqualmie Pass will end up getting some too.

The NWS guys will be busy over the next couple days. Come to think of it, so will I. :)