Monday, December 10, 2007

12/10 - 7pm - Here's the Deal...

***DISREGARD ALL CURRENT GFS MODEL RUNS (0z-18z).***

Just do it. Please. Everyone. Yes, that means you media outlets.

I've just had enough of the inadequacies showing up on the GFS for the past few days. That forecast model is worthless right now. The problem is that the Euro, Canadian, JMA, and whatever else model you can throw at me are predicting a SNOWSTORM (you heard right) on the 15-16th (17th storm for NE US that I've been talking about) for the Louisville area. Right now the GFS is taking the low that is to produce this storm right off the coast into the Atlantic and then blowing it up into a monster. Not gonna happen folks. Nope. Here's why...

  • The NAM is going deeply negative (red lines on bottom graphic): This simply means that there will be higher than normal pressure in the North Atlantic, signaling a shield of sorts to deflect all low pressure to staying within the East Coast, and not going straight out to sea.
  • The GFS (I JUST saw the 18z run when writing this post and it brought the storm back, but placement is still an issue) is still taking the low too far south and making a huge storm in Alabama, which is just not the right solution given the current dry pattern there. The low wouldn't want to infiltrate that dry high down there, instead it would want to skirt along the northern edge, which is just a couple hundred miles north of the GFS forecast location on the 16th.
  • Henry Margusity at Accuweather is actually putting us in the center of a snowfall potential map. He's been pretty good forecasting the recent storms in the Northeast and he's been doing well down this way as well (although there was the storm a couple weekends ago that surprised a lot of people and went north on us, which was a close call to begin with)

(Read Margusity's blog here)
  • John Belski at WAVE-TV is going out on a limb (I'm behind you 100% on this) that we'll see snow on Saturday with this low. He gave the three possible low tracks (out to sea, S. Alabama, and N. Georgia) and said "I see the potential for a snowstorm". In other words, he's the only one in the local TV market calling for this (WDRB is 40 degrees and slight chance of rain/snow, WLKY is mix and snow with 30's, WHAS is cloudy and upper 30's.)
So here's my thinking, let's wait until Thursday and see what the models look like. If we're in the same or similar boat, I'm going to go ahead and call for a storm. Otherwise we'll just see what happens. Throughout the next few days we'll see fluctuations in the models, but overall I think this is the best shot we've had so far at some appreciable snow this season.


Now, shorter range (Don't you just love how I think in reverse-chronological order?)

We will see highs near or at 70 tomorrow with little rain expected. What a deal in December! The saying in Louisville is, "If you don't like the weather today, wait a little bit." That's just a little urban folklore there, but hey, 70's and snowstorms can happen in the same week!

1 comment:

Anonymous said...

I'm glad you wrote it... The GFS usually is too far south with most "snowstorm" lows for the Ohio Valley, and corrects northward as time goes on. However, it is usually decent with the upper air pattern... So looking at the 500 height divergence, one might say the 00z GFS has a good handle on the storm. Although QPF may be minimized because it strengthens the southern low that eventually heads up the East Coast... all while forgeting about the northern low and deformation zone that Louisville is right under. From the 00z GFS, 1+"/hr snow rates look good at 120 hrs. Keep your fingers crossed that forecast holds. It might be the best snow since the pre-Christmas storm of 2004.

Also, from reading your posts... just some food for thought. The GFS truncates after 120 hours, so beyond that it is primarily an estimation with climatology the biggest influence. The ECMWF tends to be the superior model in the long term. Or at least I think so. Compare and see for yourself.

Finally, like the new intros to the videos... You should try and get your AMS seal. I wonder if you could? Like your site. Hope for snow.