Snow Analysis 1 am

I have output from 8 models listed below. Each gives the snow amount (approximately) at BHM for the entire event (except the WRF, which only goes through 12 UTC Saturday).

I would not look too much at the NOGAPS, as it seems to have a dry bias. Also, the JMA has predicted snow several times around here already this year, I think. So, we’ve thrown out the best and worst score (like in the Olympics), and we’re left with the UKMET and GFS giving us only 1″ or so, the GEM and the WRF giving us about 2″, and the NAM and the NGM giving us 5-6″. These numbers are for BHM…the snowier models may show even heavier amounts south of BHM.

NAM: 6″
GFS: 1″
Canadian GEM: 2″
WRF: 2.5″
NGM: 5″
UKMET: 0.5″
NOGAPS: Near 0
JMA: 5″

It’s a tough forecast. It will probably snow tomorrow night or Saturday. It will probably accumulate. It probably won’t be the Blizzard of 1993. It probably will close roads. It’s interesting that the NAM and the GFS have both been consistent, the GFS less snow and the NAM more snow.

The amount of physics that goes into these models is enormous. Yet, their main source of data is the network of weather balloons released around the world twice a day. The track of the low will depend a lot on the position of the front to our south, which is in the Gulf where balloons are not released except occasionally from ships or oil platforms. It will also depend on phasing and intensity of short waves in the upper level winds. It is hard for the models to even get these exactly right from the start, since only one balloon may see it (imagine trying to say the size of a wave in the water if you only knew the height of the water in one spot. Where on the wave are you?) This makes weather interesting!

Those posting some negative comments, give the people at the NWS a break, also. Passing something on to the midnight shift is better than doing something hastily. And how does a Winter Storm Watch (or the lack thereof) tonight affect us? They will probably issue one by 530 am anyway.

Sit back and enjoy this! It’s like a movie. We don’t know for sure what will happen. If it doesn’t snow, many will be disappointed (me too), but we just saw snow in a lot of places on Wednesday.

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