Think Snow, Tweet Snow !!!

Sunday, December 20, 2009

Model data delivering a rather frustrating result for Christmas event

And although I am holding out hope, I have to respect what the consensus of data has shown over the last 48 hours. If true it would be a very humbling turn of events for me since some aggressive proclamations were made. I will stick to these prognostications for the time being but at the same time I will reveal the details of the less than ideal model simulations.

While many along the eastern seaboard are no doubt digging out from one of the more historic December noreasters that I can remember, MRG will continue to remain dry through part of Tuesday with temperatures in the teens during the day and near zero at night. A weak disturbance will rotate into the departing east coast trough Tuesday and will enhance snow shower activity for a time and may help in bringing a fresh inch or two to the mountain. After that, we wait for the storm which departs the Rockies Wednesday with vigor and tracks toward the northeast.

Although we continue to see plenty of blocking in the jet stream which will persist through the end of the month we will temporarily lose our supply of fresh cold air this week. The below normal temps early this week will gradually modify as the airmass becomes stale by Christmas Eve. At the same time, models are suggesting that our Christmas storm takes a left turn in the southern Plains and heads for the St Lawrence Valley. It is honestly hard to believe such a track given the state of the AO and NAO but models have been spitting out such a solution for consecutive days. The adverse track of the storm will be mitigated to a degree as the storm transfers its energy to the Atlantic Coast, but if the models are taken at face value, snow will arrive on Christmas day and turn to ice before ending as a period of terrain enhanced snow over the weekend. I am not throwing in the towel on this event in spite of all these details. Below normal temperatures have helped to chill the Great Lakes and much of the east is under a healthy blanket of snow. These are subtle variables but over time can act to keep the track of this storm farther south. Blocking in the jet stream can also encourage such a storm to make a quicker transfer to the Atlantic Coast thus thwarting any warm-up. I am no doubt concerned about what the models are saying but this game is hardly over, lets see how things transpire in the coming days before officially throwing in the towel.

Ensembles continue to show a "blocked" pattern through the end of the year with weakened but still favorable teleconnection indices. Model runs over the last 24 hours have been on the drier side with snow falling mainly from clippers and terrain enhancement. There remains evidence however of an active southern branch of the jet stream so one has to be somewhat cynical of a dry forecast.

3 comments:

JTDsurf said...

I like your optimism. Let's see how it shakes out. Some sleet and wet snow will help with our base. A little TES (terrain enhanced Snow) after will be the frosting on the Christmas fruitcake.

Eric said...

Christmas Miracle, RAH, RAH, RAH!!

TJR said...

Josh,
A question if you don't mind, looking at the NOAA satellite water vapor 24 hr national http://www.weather.gov/sat_loop.php?image=wv&hours=24: Why is there so much clockwise rotation in view? Isn't this unusual? The only counter clockwise is the departing system from the northeast.
Happy holidays, and thank you for sharing your time, knowledge, and God given gift.

TJ