wxman57 wrote:What still bothers me is our (Houston) high dew points (and temperature) going into the precipitation Tuesday. It's a rare (if ever) accumulating snow event that starts out that way. I sure would feel more confident about some accumulations if that dew point started out in the low 20s instead of the low 40s as predicted now. I just don't think cold advection can get us there (accumulating snow) in Houston. Things can still change, but don't get your hopes up for a white covering on Wednesday morning. More likely, you'll just see some flurries of snow Tuesday evening that melt soon after hitting the ground.
I think the problem with the GFS is the false 10 degree warming it shows during the morning hours of tuesday before temperatures "slowly" fall for some reason as the precip is falling. I don't think the GFS has a grasp on the CAA that will be occuring tuesday morning with thick cloud cover and incoming precip. We will not warm into the lower 50s tuesday afternoon, but with temperatures in the morning in the 40s, we'll likely fall quickly into the mid 30s once precip begins in the afternoon, just like Dec 4th. But unlike Dec 4th, we won't have so much dry air to overcome. Dewpoints did begin in the 20s during that event, but all we ended up with for a very long time here on the north side was a whole bunch of heavy virga. With dewpoints higher during this event, this tells me that the atmosphere is more moist and dry air or virga will not be a problem. This to me is a positive we have going into this event.
Remember, temperatures and dewpoints were very high just before the Dec 10th, 2008 event. In fact, temperatures and dewpoints were even warmer. Highs on the 9th were near 80 (78 at IAH) with dewpoints in the 70s. CAA and evaporative cooling took care of that the next day.
How long would the sleet/snow stay during Wednesday morning if that model does verify, txsnowmaker?
