Sunday, December 13, 2009

Rain Again then Cold Air next week...

Tonight the big story is the dense fog advisories throughout the whole southeast. Visibility will be less than a mile through tomorrow morning. So your morning travel could involve some dangerous visibility conditions.

The ground has cooled over the last few days and a moist warm layer of air over the ground has created the abundant fog tonight. But expect the fog to fizzle out mid-to-late morning.

Another warm front will begin to increase more of our rain totals tomorrow. This will likely cause tomorrow to be another cloudy and rainy day. Then late Monday night and into early Tuesday morning a cold front will drift through to provide even more rain. The cold front might have some lightning and thunder embedded in the rain line, but the main front seems on the weaker side. Instability values aren't impressive, and helicity values are extremely low for South Mississippi. Looks like mainly just a rain event.

After the front we will clear out. Temps will drop down into the 50's for daytime and 30's overnight. I've been studying a couple of cold air shots going into the 5 days before Christmas. Looks like a dry cold front could kick through around Saturday and open the door for even colder temps following a second front around the 22nd. GFS has been aggressive on this forecast until today, but it looks like ECMWF is leaning towards a cold direction as well. The Arctic Oscillation is going off-the-charts negative on the 16/17, but the NAO is only slightly negative. So the cold air will be present coming out of Canada, but the air mass might not making it down to South Mississippi.

There is a lot to play out in the next week! Have a good one!


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