Archive for the ‘Forecast’ Category

Looks like we will get started fairly fast this weekend with showers and storms already taking place across a good portion of the lower Mississippi Valley this evening.  Tomorrow….some localized areas of flooding are possible ahead of the cold frontal boundary as pockets of heavy rainfall setup during the day.  Some isolated severe weather will be possible in areas where instability values can creep up, but a good chunk of Alabama will deal with easterly winds of the wedge boundary which will keep temperatures cooler east of I-65 and instability in check.  The best chance of any severe storms will be to the west and south over portions of coastal Mississippi, Louisiana, and Alabama where some marine air could spark some severe weather. 

Model output does indicate some areas receiving over 3” of rainfall north of I-20/59 during the overnight tonight and day tomorrow.  With the drought stricken conditions across a good portion of the area, flooding will not be a widespread problem unless some 5”+ totals are reached in a 12 hour period.  This does not look likely, but we will definitely watch the trends and training of cells within the rain shield.

We are beginning to worry a little more about Wednesday as a very dynamic system will take shape to our west and put is back in the warm sector yet again as a cold front heads our way.   There are questions regarding the timing and moisture quality that returns ahead of the system.   If things continue to trend toward more return flow….we will likely be dealing with a tornadic type event.  Stay tuned as we will be updating the chase status during the next couple of days to reflect on this.  Enjoy your wet start to the weekend with a movie and some relaxation like I am.

Rain and storms are going across portions of Mississippi and Louisiana this hour and are beginning to enter western Alabama.  With weak instability, low dew points, and no extreme wind shear or dynamics….we aren’t expecting severe weather.  However, this looks to be a substantial rain event.  I will be creating some graphics to identify our drought stricken areas and the area that may get excessive rainfall this weekend with our approaching storm system.  Also, the potential for a higher impact severe weather event on next week.  More later…

This is the latest Day 2 outlook from the SPC in terms of the highest threat of severe weather on Monday.  There is a slight risk in tact for the northern 2/3rd’s of Alabama as well as northeast Mississippi and north Georgia.  The parameters are there for some isolated super cell convection along with the threat of tornadoes.  The tornadic threat will be prevalent with any cells that can form ahead of the line as well as cells embedded within the line.  Shear will weaken with time, but moisture is already outdoing the forecast and can overcome the shear values at times.  We will be updating with our chase target mapping for Monday morning when we plan to deploy as well as updating with our own risk graphics.  However, the SPC does mention the potential for higher probabilities and maybe significant probabilities in later outlooks as the features become more clear. 

Stay with us as we prepare for our first real chase of the 2011 storm season. 

A Red Flag Warning has been put out due to high fire danger all around the state today.  We are looking at temperatures in the 60’s with very low dew points and some wind around.  This creates an environment for fires to stir out of control in a hurry.  Please heed these advisories and don’t burn anything unless you have to.  Keep a hose pipe around and do it in a safe location if you MUST burn.

Warm and dry conditions will continue through much of the week.  We will be doing some transformations to our video streaming page due to our resignation from Severe Studios this past week and will continue to work on revamping graphics for the page as well as putting things into place for severe weather and tour season.  Email us with any questions or inquiries….  alabamastormtrackers@gmail.com

Well, we didn’t get to update as much as would have liked here for the snow event, but we were working on the Bama Camera Network.  This wasn’t an overly major event, but everyone saw a decent snowfall from it across Central Alabama.  Here is the forecast map the we created before the event…

The forecast map actually lined up pretty well with the totals that we experienced over the last 24 hours.  Given that the event wasn’t long duration….things were forecast pretty good by the shorter term guidance and the various forecast offices and television meteorologists.

The heavier snow bands setup across West Alabama and then transitioned to south of I-20 as heavier precipitation spread northward as our mid level vorticity max swing out and enhanced things a bit.  Be advised that we are also working on our graphics and different logos for the site so you may see some tests on our products. 

One of our viewers, Bret Causey, of Clay County took the pictures below from Bull Gap mountain on HWY-148 near the Clay/Talladega County line. 

The images were beautiful and a few inches of snow still remains on the ground at the top of the mountain.  Temperatures are expected to remain close to freezing today before the major warming trend begins on Friday. 

Here is an awesome panoramic shot of the mountain from Alabama Storm Tracker, Eric Parker.

If you have snow shots from your given location…please feel free to send them in and we will get them on the blog.  Now that the snow event is over with….expect a warming trend in the near future. 

Well, an interesting setup is evolving across portions of Louisiana, Mississippi, and south Alabama this evening and over the next 48 hours.  A shallow layer of cold air will hamper forecasts area wide and will set the stage for sleet, freezing rain, and even snowfall along the northern edge of the precip mass expected to develop.  Some precipitation has reached the ground across south Mississippi and Alabama this evening with sleet being reported across parts of Jackson County, MS and Mobile County, AL.  Heavier areas of winter wx are expected to begin developing later on tonight and the shield will expand northward toward the Jackson and Birmingham metro areas into Thursday.

There is a problem evident across several locations for precip this evening given it’s light nature.  The soundings indicate a decent amount of drying in the lower levels of the atmopshere.  Here is the sounding from Slidell, LA.

You can see the temperature (red) and dewpoint (green) lines separate down the 850 – 925mb levels begin to separate pretty significantly.  This indicates drier air at these levels and the rainfall will have to moisten up this part of the column via evaporation before we can see any appreciable precipitation at the surface.  A little further north…..the Birmingham, AL sounding shows this well also.

This will be something we have to watch in our area for some freezing rain, sleet, or even snow across Central Alabama.  Tonight, sleet and freezing rain will be possible south of I-85.  The heavier precip comes for us tomorrow.  Stay tuned…

Our current high resolution radar shows some lighter showers spreading into the area this hour with the bulk of the rainfall staying south of I-20 where it has remained most of the day.  It looks like some showery activity can be expected for the rest of the night across most of the area with the heaviest rainfall staying to the south.  This will begin to taper off during the day on Monday and give way to mostly cloudy skies.

The Storm Prediction Center in Norman, Oklahoma has issued there latest day 2 convective outlook for Tuesday.  The threat has expanded some to the west and they mention higher instability values potentially being present as temperatures are a big warmer on current model runs for the Mississippi area.  There is now mention of rotating storms with a highly sheared low level environment and the potential for a couple of super cell thunderstorms across LA/MS during this time.  We are going to upgrade our chase status to MODERATE for the likelihood of chasing across the Jackson metro area on Tuesday.  Continue to monitor the blog concerning this as things may change before Tuesday.

Now….we won’t talk much about it but the models are starting to pick up on something pretty big for the weekend.  This is the Canadian model that has performed pretty good in the longer range this winter….and it shows some Winter mischief across Mississippi and Alabama in the form of ice and snow on Saturday.  We will fine tune things before then, but the idea is definitely on the table.

This afternoon….temperatures are in the mid – upper 60’s once again across much of the area.  The shortwave we talked about last night is moving across the Lower Mississippi Valley region with rain spreading eastward somewhat.  The WRF model output from last evening may not have been generous enough on the rainfall totals especially across western sections of the state.  Radar already indicates some 3/4” totals across portions of Pickens County with the activity. 

We still expect some of this to diminish this afternoon as it moves eastward into drier air east of I-65 where dewpoint values are still in the 40’s.  Most of the heavier activity should remain south of I-20 even as the rain continues.  Lows tonight should be in the 40’s with the clouds hanging around.

Still expecting some strong to severe activity on Tuesday into Wednesday as a potent system moves in our direction.  The threat may have actually increased for portions of Alabama.  Stay tuned…

Wow…..what a difference a few days make.  We had high temperatures in the 70’s across much of Alabama today with many places nearing record levels. Yes, I said record heat levels instead of cold!  Enjoy it while it lasts because there is more wintery type temperatures in the forecast.  However, today was picture perfect for a day of fishing at the lake or just playing outside with the kids. 

Now….we will look at the current weather maps…

Tempeatures are running in the 40’s and 50’s across the area this evening with clear skies overhead.  We should radiate down into the 30’s with no problem before too much longer.  You will note the spike in temperatures to our west in the Dallas/San Antonio vicinity ahead of our next storm system.  This is setting things up for parts of the southern plains and Midwest to get a rather significant winter storm that is expected to stretch from Oklahoma City to the Great Lakes by Tuesday and Wednesday.

Radar shows some scattered activity breaking out across parts of Texas ahead of the surface front and associated area of low pressure.  The main shortwave is still back over parts of northern Mexico….so it will likely be later tonight before and real established convection gets going and produces anything of significance. 

The SPC has a convective slight risk in place for portions of the SE Texas area mainly for the potential for some wind and hail later in the overnight hours.  This isn’t expected to translate eastward at this point for tomorrow or Monday because we are too dry for any kind of severe weather.

This wave will effect us with some rain late tomorrow night….likely after midnight.  The totals shouldn’t be impressive as the wave will be shearing out across the area and the main precipitation will be decaying.  Totals of less than .25” are generally expected and are advertised by the NAM above.

Now….we are looking into the idea of the second wave that will bring the winter storm across the plains and Midwest possibly setting the stage for some severe weather across the Lower Mississippi Valley region by Tuesday.  The setup involves a strong trough going negatively tilted while intensifying wind fields overspread the area.  The general downfall for these kind of events in the winter is the lack of instability that is associated.  Dynamics can offset instability at times and this could be one of those cases….

These 500mb wind fields are extremely strong and are divergent across the eastern Ozarks and Mississippi Delta region.  This map is valid at 3pm on Tuesday.  The trough is taking a negative tilt as the surface low is beginning to accelerate out of E AR/W MS.  This is a prime setup for severe storms across the deep south.

These shear values of >45+ knots are indicative of very strong low level turning in the atmosphere.  These values are from about 5000ft to the surface.  This indicates extreme shearing will be present in the lower levels of thunderstorms that are able to develop and that they will likely obtain rotation if an updraft can become sustained.  These dynamics will be moving east and northeast.  From this, I do get the idea that damaging winds and potential for some tornadoes will exist across portions of Mississippi and later into West Alabama.

These are the 3km EHI values.  This is an “energy-helicity index” that indicates where the best shear and instability will be present.  Values over 1 are indicative of the potential for significant tornado development.  You can see a bulls eye of near 2 over Natchez, MS at 4pm on Tuesday.  This has been steadily on the rise for the last few model runs as somewhat higher lapse rates and instability values are coming into play.

Finally…here is the forecast sounding from the Jackson, MS area at 3pm off of the 00z NAM model. This shows a very moist column.  The temperature is steadily falling with height and does so pretty rapidly from about 650mb to 300mb.  There is a dry layer there that indicates some potential instability and faster falling temperatures with height.  We will watch for drier air around the 700-750mb level.  This will be key in the formation of deeper instability values.  More dry air at this level can mean less thick cloud cover and higher temperatures in the lower levels creating a “steeper” lapse rate….or cooling of temperature with height.

So, what are we saying?  Basically….I expect the best severe threat to be west of Alabama due to the time of day and nature of the system.  Sure there will be a threat during the overnight Tuesday into Wednesday morning for some isolated damaging winds and maybe a tornado or two, but the better threat sure seems to be over Mississippi at this point.  We are likely going to chase this system if instability parameters continue to improve across the region.  If we can keep the widespread convection at bay….there could be a few tornadoes over there.

We will post more on our plans over the next few days, but for now back to getting the laptop ready for “chase mode” as well as the truck.  Have a good weekend!

Our ULL is moving out and our forecast thoughts were generally in line with the idea of snow being pretty meager even across North Alabama this morning.  It turns out Huntsville and Monte Sano only received a dusting of snow.  Also, heard reports of freezing rain and sleet in that area.  The idea of the snow growth region being dried out a while was correct too.

As for today….a wind advisory is in effect for eastern sections of our area due to a tightening surface gradient to our east.  This will bring some windy conditions east of I-65 with gusts over 25 mph being possible at times.  At least the sun is coming in with the wind this time. 

We expect a quiet few days with lows in the 20’s during the overnight and highs into the 40’s thru Thursday.  Another big shot of cold air looks to be on the table around the first of February along with some wintery mischief.  We will have to watch that because things change rapidly around here as we have seen this winter in terms of snow and ice.  Have a great Wednesday!