Wednesday, January 13, 2016

Wednesday Morning Storm Forecast: Updated Forecast on Powerful Weekend Storm

I'll tell you this storm is tough. The models have been very consistent with a very strong coastal storm developing but cold air is scarce. This makes putting together a snowfall forecast extremely difficult considering the snow will depend on small scale features within the storm. However, I took a shot at it and my updated forecast is below.

Here is a summary:

  • A big storm effects the area Friday night into Saturday
  • For the blue zone I expect all snow with several inches accumulating
  • The pink zone is the battle ground for this system 
    • I expect everything to start as rain here
    • However as this storm blows up of the coast it should pull cold air in
    • This would cause rain changing to snow with a few inches accumulating
    • This is the hard part of the forecast and I will have to keep tweaking this area
      • I cannot rule out more snow or all plain rain at this time, both are possible
  • The light green zone I expect mostly rain with the chance at snow for the last few hours of the storm as it pulls away
  • Dark green zone is all heavy rain and wind
At this time models all agree on the strength of this storm but the track and precipitation type are still up for a major debate. The latest GFS model makes sense to me below..

If you look closely you can see a 976 MB low pressure system and blue or snow trying to work its way into my "pink" zone. This is the model trying to pick up on dynamic cooling or in other words rapidly rising air which lowers the pressure and cools the atmosphere and turns rain to snow. The million dollar question is does this happen. I think given the strength of this storm it will. 

European had a very weird run last night and kept storm less phased and more off shore. This adds a whole new possibility into this as that would mean any snow for cold areas is light and this storm basically misses the area! I do not think that will happen but I need to point out it is a possibility. Its ensembles are more west.

The reason why this storm is having a problem with cold air is because of the first storm that develops to the west. That first storm brings in warm air. Otherwise the actual track of this coastal low is textbook perfect for snow. Too bad the atmosphere is spoiled ahead of it. Do not underestimate the possibility for that :dynamic cooling" though. I really think this storm can manufacture its own cold air for the pink zone.

Thanks for reading I will update tonight around 830. I am sure there will be interesting developments today! 

Hopefully I will not have to change my forecast drastically. We shall see!

To make matters even more crazy there is the chance at a follower storm sunday night into at a time tho.

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