Friday, December 30, 2011

A Cold, Stormy Pattern on The Horizon?

After a very dry and mild November and December, the big question is when is this going to change and when are we going to get some snow and rain?

The main issue is the blocking high off the coast of California. This has deflecting every approaching storm to our north/northeast.  Even this weekend we will see another short lived ridge build over the Northstate clearing us out and keeping us mild.
Now we mainly use forecast models, including the images I'm including in this blogpost, as tools rather than a conclusion of what's going to happen.  We look for pattern changes rather than the exact placement of a low, high, or large Gulf of Alaska trough.  Here's the latest GFS model run from Friday morning.  It should be noted that this is the third big run in a row that includes a cold/wet pattern ahead.
This is this coming Thursday (Jan 6th).  Our first semi cold/wet system in a while.  This system should be out of here by Next Friday and we will likely clear back out for another 3-4 days.  Before an even larger pattern change..

Forecast models are now hinting at a sustain cold/wet outbreak as early as January 10th.

Again just use this as a tool not a end all be all.  But by two weeks from now a very stormy pattern setting up for the Northstate.  A wave train of storms out of Alaska!  Lots of time in between but it should be fun to watch and track the next 1.5 to 2 weeks!


Rob







Friday, December 16, 2011

INDIAN OCEAN ACTIVITY COULD END THE NORTHSTATE'S DRY SPELL


The last 4 weeks the Northstate has remained dry, mild, and sunny.  The main culprit....a large blocking high pressure system to our west.  This high has blocked any system from penetrating the Northstate.  The only activity has been low pressure systems rotating clockwise around this high and brushing us on the northeast side.  We call these backdoor sliders, which are typical Northstate wind events.

Why has this been occurring?  We are in a weak  LA NINA??  Well a few things, activity in the poles and arctic have been weak.  This has kept the jet stream from buckling and sending waves and storms down south to the Northstate.

Another large factor is the MJO Activity (Madden Julian Oscillation) it's been non existent the last month.  THE MJO plays a huge factor in the Western United States in the Winter, especially in weak LA NINA/Neutral conditions(which we currently are).

Here's where we are. the last month nothing, but you will notice the orange (thunderstorm activity) beginning to emerge into Frame.



Here's the 15 day forecast, a huge event occurring towards days 11-15 in the Indian Ocean.

So what does this mean??  Notice the blocking high in this first phase and then the transition.
This phase shift will probably take some time to work into the Southern Pacific and does not guarantee any big storms but it is a light at the end of the tunnel

here's some material on this.....