Rain Chances Increasing

There won’t be any video with the discussion this morning due to limited bandwidth where I am. I plan to have a video here with the discussion tomorrow morning. The weather is cool but pretty in Tallahassee this morning with a steady east-northeast breeze.

And it’s a bit chilly across Central Alabama as the airport observations range from the upper 20s to the upper 30s. Clouds will be on the increase today as we see the cirrus clouds thicken. The atmosphere which was still pretty dry across Central Alabama according to the sounding from the Shelby County Airport last night will be moistening up throughout the day and night. After a really cool day yesterday we should see the temperatures climb into the middle 50s – maybe even upper 50s.

We’re setting the stage for a rainy/stormy period which is certainly welcome with the rainfall deficits still running well above 20 inches. This morning a strong trough extended from the western end of Lake Superior southwestward to extreme northwestern Mexico. At the surface, a large high pressure system was situated over the eastern seaboard with a developing storm system in the area of Texas. As southerly wind develops over the cooler air at the surface tonight, we should see an overrunning situation with light rain and drizzle breaking out this evening for Central Alabama. I would expect to see some rain begin around midnight or so this evening. I think there is a pretty good chance the big game in Auburn will stay dry, but if I were headed there, I’d be taking some rain gear just to be safe. It will be relatively cool, too, with temperatures hovering around 50 for much of the game.

A surface low should be on the map by Sunday morning in the vicinity of Houston, TX. The surface low will shift northeastward to near Memphis by mid-day Monday putting us into the warm sector. The Storm Prediction Center (SPC) has outlooked an area of Southwest Alabama, Southern Mississippi, and Southeast Louisiana for a slight risk of severe weather for day 2 from Sunday into Monday morning. The big question for our forecast for Central Alabama will be how far north the really juicy air will get. The GFS output puts lower 60-degree dewpoints in here between 6 pm Sunday and 6 am on Monday but the associate Lifted Index values are not impressive. The NAM, on the other hand, keeps dewpoints only in the upper 50s and CAPE values really low. These are often tricky situations that bear watching right up to the last minute in order to see exactly how far north the greatest instability can travel.

The surface low passes to the north of us on Monday with the front coming through here in the afternoon. The weather should clear out on Tuesday with a slight cool down. Rainfall amounts across Central Alabama area expected to be in the 1 to 2 inch range. This should be a fairly good soaking situation, but with such a large deficit, it certainly won’t break the drought – maybe nick it a little.

Thursday the GFS shows the long wave trough over the eastern half of the country with a reinforcing shot of cold air headed south. It also looks like the disturbances coming through the trough could come by here dry. But a new disturbance over the Northwest US by Friday shifts the trough off the East Coast putting the southern tier of the US in a zonal pattern aloft and shunts the colder air off to the east and not south.

By Sunday, December 2, a new surface storm is developing in the Central US as strong short wave kicks out of the West. But this is edging into voodoo territory, so we’ll have to see how this unfolds. We need to get through the near term event first.

Further into voodoo country, the GFS depicts a fairly active pattern with a good shot at some more rain around the 6th. The really active flow does retreat northward a bit at the end of the cycle.

Hurricane season 2007 ends later this week, but remember that we are still in our secondary severe weather season. This means we need to keep a close eye on the developing situation for the next couple of days. Let’s hope it brings good rain but no serious severe weather. Be safe this weekend if you are traveling. God bless.

-Brian-

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