Archive for the ‘Cold’ Category

The coolest weather of the fall season is likely coming over the next week.  A major east coast storm is forecast to develop and bring down much cooler temperatures with it by the 20th of October.  Some rain and thunderstorms will be possible ahead of the front for our area, but severe weather doesn’t look to be a major issue this time.  Cool air will likely be the main story line.

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 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!

Winter Storm Warnings have been issued by the National Weather Service offices in Memphis, Nashville, and Huntsville for most of there counties.  Memphis covered there western counties with Winter Weather Advisories for lesser amounts of snowfall.  I have some agreements and disagreements with some of these advisories…..and I will get into those after looking at the latest and forecast output.  To the maps….

Our upper level system is still digging to the west over portions of Texas at this hour.  The trough has yet to close over, but with very significant vort surrounding the system and indications of deepening….this should happen over the next several hours to our west.  You can see that the flow out of this level is out of the SW…..which will bring me to another key point.

You can see our developing upper low that I have marked to the west….but this is overlaid on current water vapor imagery.  The yellow colors indicate large mid level drying occurring to our SW and now intruding into Mississippi and west Alabama.  This will play havoc with the moisture column in the mid levels and likely dry out a good portion of the snow growth zone….at least for a while until the main low pressure system moves overhead….if it ends up moving across North Alabama.  The latest high res model runs indicate this happening somewhat. 

Here is the upper level low at 6AM on the WRF-ARW model.  This is a high resolution model that seems to be handling things pretty well in terms of the synoptic and low levels…along with precip fields so I will stick with it.  The core of the ULL goes right along the Tennessee border.  Usually, the highest QPF (accumulated precip.) is to the northwest and southeast of an upper level system.  The heaviest snow axis per this run should run from east of Memphis to Nashville to southern Kentucky.

Here is the 3hr precip forecast for the same time frame.  I have overlaid my “Heavy Snow Axis” over the model where I think the heaviest amounts will occur.  Given the model output and soundings, I think it is safe to say that Nashville could see upwards of 3-6” of accumulating snowfall….with maybe a 7” total somewhere.  The most likely place to see any heavy accumulating snowfall in Alabama will be the highest terrain in Northeast Alabama and the Shoals area.  I’m skeptical about NE AL because they could get dry slotted being in the SE quad of the upper level low as it is pivoting.  In other words….places like Skyline and Jackson County could be left dry.

The old saying is…”Upper Level Low, Weatherman’s Woe” and that could prove to be the case this time.  There is extreme difficulty in forecasting the dynamics and thermal profiles with these kind of systems…..along with precipitation fields.  This forecast looks pretty good as of now and I will stick with it.  So, I just don’t see the Huntsville counties verifying warning criteria snowfall…..but I hope you do!

We will post more updates throughout the evening as conditions deteriorate or warrant…

Tonight on the radar we are seeing some developing flurries across West Alabama with a wave that is passing through.

Not expected to be anything major, but still interesting none-the-less.  Temperatures are in the 20’s so any precip will be in the form of snowfall.

Our next wave is showing up in the NW this hour and will bring us some rainfall by early Monday.

This system will once again be minor, but models are starting to key in on a potential winter weather maker that could bring significant snows to the deep south by late Tuesday into Wednesday.  Here is our short range ensemble model as of the 21z run of the system.

Deep upper trough over portions of Alabama with a lot of spin and lift in the atmosphere.  This is a good setup for falling surface pressures and cyclogenesis.

This NOGAPS chart shows a similar scenario with parts of Alabama getting pounded.  Not much time this evening but will go more into detail tomorrow.  Have a great night.

After looking at everything this morning….I believe that we are still in decent shape with maybe a few changes needed on snow totals and ice accumulations later on this afternoon once we get a full suite and days worth of data.  Current indications are that we may need to adjust our icing totals upward south of the I-20 corridor.  We will get into that later.

We are planning to build a large page with our team members live video cameras from different locations around the state.  If you are interested in possibly helping us out and would like for your camera possibly shown on a local news affiliate during the storm….send me a message to bamastormchaser@gmail.com and we will get you setup and ready to stream the ice and/or snow event at your location.  This will in the process help us with real time views to correlate radar data with what is actually happening.

Our next update will come later in the evening as we prepare our next call on the winter weather situation across the deep south.  Have a great Saturday!

The model above is the GFS.  One of our global models that we look heavily at when it comes to our weather.  Looks as if the model is trying to depict a scenario of some ice/snow potential for Central/North Alabama and maybe even areas to the south like Troy and Andalusia as we enter the late Sunday into Monday time period.  Keep in mind this is just one run of one model.  However, some of the past runs of other model data have depicted a similar scenario. 

This evening a few of our other models have decided to veer from a consensus and show a couple of other possibilities.  The CMC (Canadian) model is now showing a warmer picture with the surface low riding through Birmingham and pulling northeast bringing an all rain event….and maybe some thunder to southeastern counties.  The ECMWF still has the Gulf surface low on schedule and brings it eastward along the coastline.  This model is in track with our GFS model above except it is a tad warmer this run suggesting some wintery precipitation and rain mixing. 

What we can say right now is that we are rather confident that portions of the area will see a winter weather event this weekend.  This definitely has the potential to be a high impact event…..in the form of ice, snow, or both.  We won’t talk potential totals until the Friday/Saturday time frame, but we do expect for some accumulations and travel problems across portions of the area. Stay tuned to later forecasts and analysis from us as the event approaches and more details are brought to light. 

There has been a signal on them models for a while that indicates that the deep south could deal with some pretty brutal cold air in the coming couple of weeks…..along with some winter weather potential.  However, the thing we are going to key in on currently is the cold.  I want to show you a model that does very good in the medium range….the European.

The latest 12z run of the model that we have in indicates at large Polar Vortex to our north swinging a cold front and deep upper trough thru the region.  We have a blocking ridge developing over the west coast at the same time which usually spells for some pretty cold air coming into the country and that’s exactly what we see.  A densely cold 1058mb high pressure system over western Canada has trajectories of pushing very cold low level air into the eastern 3/4 of the country.  If this were to verify…..in the extended range we may very well deal with some record breaking cold air.  Remember….winter is just beginning. 

A few days before Christmas we were pegging on a potential Christmas winter storm that could plague parts of the southland with there first white Christmas ever.  This all turned to fruition during the early morning hours of the 25th and gave most of us what we had all been waiting for.  To the setup…

The night before the short range models started coming in more aggressive with precipitation.  These models started showing accumulations throughout the southeast region including north and central Alabama.  Here is a model image of the 00z BAMS model that is derived from Baron Services in Huntsville, Alabama.  Baron Services provides broadcast media with in house computer graphics for radar and weather modeling.

This model began showing the 2” criteria snowfall that is border line for a winter storm warning in this part of the country.  So, now that things began locking in on a greater snowfall potential we were watching this system develop from our homes.

The morning of Christmas Eve, December 24th, our system was developing in western Texas and to the north across the Dakotas.  We watched from our in-house system as the upper air system strengthened and moved across Texas as snowfall continued to move southward from Illinois, Iowa, Missouri, and Kentucky.

The surface low began to crank in far south Texas and precipitation was much more expansive that forecast by the short term models over portions of Texas, Oklahoma, and Arkansas.  This led many forecasters to believe that even with a more aggressive approach that the models may be coming in a bit too weak with the system.  The European, the most aggressive model of them all, was beginning to look like a good solution to place your bets on.  By the late evening hours and early morning hours on Christmas…..winter weather advisories/warnings began to fly.

It is nearly unheard of to have winter weather advisories down to Dothan, Alabama any time of the year much less Christmas.  However, this was a good call as snowfall began transitioning southward the morning of the 25th as our surface low transitioned along the coast with new upper level energy moving in to bring the colder air aloft with it.  Local radars began showing the transition zone as a “bright banding” feature.

Above is the transition zone around 10 am across portions of Jefferson, Shelby, and Talladega County Alabama on the leading edge of the precipitation.  This bright banding was due to some evaporation of the heavy precip. aloft.  It was reaching the surface in the form of sleet and snow as the column above cooled to isothermal.  In other words…..the heavy precipitation brought the colder air down with it to the surface allowing the mixture or changeover to all snow.  Basically….here was the end result for most areas.

Snowfall totals varied across many locations with Central Alabama receiving 1-2” in most cases with heavier totals of 4”+ in the Huntsville area.  Portions of Jackson County took 6” with power flickers being reported before the snow ended.  Black ice also became a problem when all was said and done as the cold air and windy conditions settled in.  Another winter weather advisory was required on 12/26 due to a large upper level low dropping in and bringing in colder air aloft allowing the low to wring out all over the moisture available in the atmosphere.

As the low moved northeast…..the BAMS models was pinpointing a potential major blizzard for the northeast.  Parts of NJ, NY, MA, etc. expected to get 2’ of snow!  Here is the BAMS model assessment of the situation from 00z 12/26.

Now…..here are the results from Vimeo user Michael Black of New Jersey.  These are images shot from a DSLR in a 5 minutes sequence during the blizzard.  Amazing 20” snowfall for these folks.

This is likely something that many of us in the south may never see again in our lifetime.  This is the first recorded white Christmas for parts of the Birmingham CWA since records have been kept.