Archive for February 7th, 2010

Why The Clouds?!

This is probably one of the last visible images of the day before the sun sets, but you can see the clouds are very thick across much of Alabama.  Why did the clouds hang around all afternoon?  Well…I think we can give you a couple of answers. 

The chart above is at the 925mb level….or about 2000-3000ft above the surface.  The blue line represents the freezing line at that level and the bright green represents saturation at that level.  If you notice the winds are coming out of the north at this level where moisture is also present.  Therefore, the low level clouds didn’t really break up very much today.  Over in Georgia where the drier air was present….the clouds were able to erode.  Just another forecasting headache when it comes to temperatures.

Potential Winter Weather Event Late Week

I said earlier that I wasn’t going to talk too much about it, but after going over the model forecast guidance this morning I have been a bit inspired by what I have been seeing.  I will go ahead and get into the system just a bit, but I will caution you that winter weather forecasting more than 2-3 days in advance is just pure speculation at this point.  So….on to the maps!  First we will start with our 2PM regional temps this afternoon.

Current temperatures are running in the 30′s area wide.  We discussed this morning that cloud cover might be an issue and it has.  It just doesn’t look like it will break for most of the area so mid 30′s for the max temps today are a good bet.  Had this thick deck moved out….we would likely be sitting somewhere in the mid/upper 40′s right now.  That just didn’t happen so we will deal with these kind of temps for the remainder of the afternoon.

We are still looking at a rainy system coming in Tuesday with temperatures in the 40′s/50′s during that event so precipitation will remain all rain during that time frame.  Some of the rain could be locally heavy causing some of the more prone areas to deal with some slight flooding issues.  I don’t foresee this as being a huge rain maker, but 1″ or rain is possible.

Now, to the main feature during the period.  Morning guidance has came in alot wetter than some of the previous packages.  We are looking at a situation where cold air will blow in after the Tuesday system.  Another southern stream wave will begin to organize over Texas by late Wednesday into Thursday and allow for surface pressure falls and rain to spread over the Texas area into the Gulf.  As of now, our temperature profiles are beginning to look cold enough that we could deal with some snowfall across portions of Central/North Alabama especially on Friday.  We’ll post a couple of model images below…

This is Friday evening at 6PM.  The Operational GFS model is showing a well defined surface low pressure system about 60 miles south of Pensacola with widespread rain north of the system.  The surface freezing axis runs from about Jackson – Clanton – Atlanta on this run.  There are a couple of other models that are showing this area being below freezing as well.  Current indications are that this area could remain all snow throughout the duration of the storm system.  *IF* this model were to verify….this would be winter storm criteria with some folks seeing a 6″+ snowfall possibly.  As I have said many times, this is just speculation right now but the cards are on the table.

Above are the GFS Ensemble plots for the same time frame.  We use these to note basically if a system is there and if it could be of the winter/spring variety or not.  What I can take from this is that most of the ensemble plots show that it will be a wet system and the freezing line will be near by.  Therefore, all in all confidence is increased because of this.  Most plots are showing a pretty major storm system organizing in the northern Gulf….which follows suit with the operational GFS model.  A few other models…(Canadian/European/FIM) are also showing a system and the cold air in place, so the time to start preparing is coming pretty quickly. 

While we won’t be able to give a more specific forecast until around Wednesday….we are thinking that there will be wintery weather across our state as we head into next weekend.  Stay tuned with us for further updates as we approach this potential winter storm situation.

Clouds Hang Tough

Clouds are hanging tough this morning and area temps especially across central sections are having a very hard time climbing.  The greater Birmingham area is stuck near the freezing mark with 31-33 being reported at most locations….but there are some breaks across the southeast areas where the temps are trying to rocket toward the 40 degree mark.  The clouds are trying to build back in however, and the rise will likely only be temporary at least for the time being.

A major storm system is gathering strength across the four corners region….noted over AZ/NV/UT in the image above.  This system will move eastward and allow for widespread snow/ice/rain to develop across the southern plains later this afternoon.  Winter Storm Warnings are in place over a good portion of Southern Kansas, Northern Oklahoma, North Texas, and Northwest Arkansas.  Snowfall totals of 5-10″ are expected across these areas. 

Rainfall will develop across Central Texas later today where some hail will be possible as cold mid level temperatures overspread the region.  This system will move eastward across the Lower Mississippi Valley and Gulf Coast states on Tuesday and bring rainfall to Alabama.  Amounts of around 1″ will likely be common as with our past couple of systems.  Localized flooding could once again be an issue given the saturated grounds…especially along river basins.

After the first system ejects….cold/dry air will set firmly in place across the state through the end of the week.  At this time…another potential weather maker will develop across Texas during the day on Thursday and move eastward into the Gulf of Mexico.  This system has the potential to bring some precipitation to Alabama.  At this time, I won’t put that into the forecast because the dry air at the lower levels could keep rain or snow from reaching the surface.  However, this could change in later forecasts.  Just keep in mind that we are monitoring the potential for a storm system at the end of the week that could bring frozen precip.  More later…