The Ice Storm is still ongoing with a small amount of precipitation still falling.  It looks as though the .10 to .15 we have gotten may be about the max we are going to see.  Thankfully, a dry slot has found its way into the southern Mississippi and Alabama area which looks to cut off the flow of precipitation.  This doesn’t mean that the danger is completely passed, but it is not likely that we will have a significant amount later this evening or tomorrow morning.  At the present time it appears that we may well keep electricity, but the highways are still dangerous and travel is not advised.  Here is the radar as of a few moments ago.

The weather is just about to take a turn for the worse in the South Sumter area.  The SPC has a mesoscale discussion in place for this area that discusses the freezing precipitation The heaviest precipitation is just about to get into the area as the radar image below indicates. 

Heavy Precip moving NE. 

The NWS Birmingham makes the following projections on the time frame for the event. 

The bottom line is the storm us just now getting started.  The information from the SPC indicates that they expect this to get much worse before it gets any better.  

Information from the SPC.  Here is the text of the Mesoscale Discussion: 

MESOSCALE DISCUSSION 0013

NWS STORM PREDICTION CENTER NORMAN OK

0306 PM CST SUN JAN 09 2011

AREAS AFFECTED...CNTRL AND N-CNTRL MS / W-CNTRL AL

CONCERNING...WINTER MIXED PRECIPITATION

VALID 092106Z - 100100Z

INTENSIFYING MIXED PRECIP RATES ARE FORECAST TO DEVELOP OVER THE

NEXT FEW HOURS ACROSS MS AND THEN SHIFT EWD INTO W-CNTRL AL BY EARLY

EVENING.  HOURLY LIQUID EQUIVALENT PRECIP RATES RANGING FROM

0.05-0.10 INCH ARE EXPECTED FOR SEVERAL HOURS WITH LOCALLY HIGHER

RATES POSSIBLE. 

EARLY AFTERNOON SATELLITE IMAGERY INDICATES THAT A ZONE OF STRONG

DEEP LAYER ASCENT /DCVA/ IS MOVING ENEWD ACROSS THE SABINE RIVER

VALLEY THIS AFTERNOON AND WILL MOVE ACROSS THE LOWER MS VALLEY THIS

EVENING.  AHEAD OF THIS FEATURE...WARM CONVEYER UPGLIDE IS OCCURRING

ABOVE A SHALLOW COLD DOME THAT IS CONTINUING TO DRAW COOL/DRY AIR

INTO THE REGION FROM A SLOW TO ERODE SURFACE HIGH OVER THE OH

VALLEY.  THUS...INITIAL MOISTENING IS OCCURRING IN THE MID-LEVELS AS

SEEN BY JAN/BMX 12-18Z RAOBS.  RICHER MOISTURE CONTENT ALONG THE

GULF COAST VICINITY HAS BEGUN TO GRADUALLY MOVE NWD INTO THE LOWER

MS VALLEY PER REGIONAL RADAR MOSAIC DATA THE PAST FEW HOURS.  AS

THIS OCCURS...EXPECT THE PRE-CONDITIONED COLUMN TO SATURATE QUICKLY

AND RESULT IN WET-BULB COOLING AND ONSET OF APPRECIABLE PRECIP RATES

/0.05-0.10 INCH PER HOUR/.  FORECAST SOUNDINGS INDICATE FREEZING

RAIN WILL PRIMARILY BE THE PRECIP TYPE INVOF THE I-20 CORRIDOR WITH

SLEET/SNOW FARTHER N AND NW NEAR HWY 82.

..SMITH.. 01/09/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BMX...MOB...MEG...JAN...

LAT...LON   32248706 31858756 31799063 32139090 32969101 33359061

            33738825 33638737 32978686 

MESOSCALE DISCUSSION 0013

NWS STORM PREDICTION CENTER NORMAN OK

0306 PM CST SUN JAN 09 2011

AREAS AFFECTED...CNTRL AND N-CNTRL MS / W-CNTRL AL

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 092106Z - 100100Z

INTENSIFYING MIXED PRECIP RATES ARE FORECAST TO DEVELOP OVER THE

NEXT FEW HOURS ACROSS MS AND THEN SHIFT EWD INTO W-CNTRL AL BY EARLY

EVENING.  HOURLY LIQUID EQUIVALENT PRECIP RATES RANGING FROM

0.05-0.10 INCH ARE EXPECTED FOR SEVERAL HOURS WITH LOCALLY HIGHER

RATES POSSIBLE.  

EARLY AFTERNOON SATELLITE IMAGERY INDICATES THAT A ZONE OF STRONG

DEEP LAYER ASCENT /DCVA/ IS MOVING ENEWD ACROSS THE SABINE RIVER

VALLEY THIS AFTERNOON AND WILL MOVE ACROSS THE LOWER MS VALLEY THIS

EVENING.  AHEAD OF THIS FEATURE...WARM CONVEYER UPGLIDE IS OCCURRING

ABOVE A SHALLOW COLD DOME THAT IS CONTINUING TO DRAW COOL/DRY AIR

INTO THE REGION FROM A SLOW TO ERODE SURFACE HIGH OVER THE OH

VALLEY.  THUS...INITIAL MOISTENING IS OCCURRING IN THE MID-LEVELS AS

SEEN BY JAN/BMX 12-18Z RAOBS.  RICHER MOISTURE CONTENT ALONG THE

GULF COAST VICINITY HAS BEGUN TO GRADUALLY MOVE NWD INTO THE LOWER

MS VALLEY PER REGIONAL RADAR MOSAIC DATA THE PAST FEW HOURS.  AS

THIS OCCURS...EXPECT THE PRE-CONDITIONED COLUMN TO SATURATE QUICKLY

AND RESULT IN WET-BULB COOLING AND ONSET OF APPRECIABLE PRECIP RATES

/0.05-0.10 INCH PER HOUR/.  FORECAST SOUNDINGS INDICATE FREEZING

RAIN WILL PRIMARILY BE THE PRECIP TYPE INVOF THE I-20 CORRIDOR WITH

SLEET/SNOW FARTHER N AND NW NEAR HWY 82.

..SMITH.. 01/09/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BMX...MOB...MEG...JAN...

LAT...LON   32248706 31858756 31799063 32139090 32969101 33359061

            33738825 33638737 32978686

Conditions continue to deteriorate in the South Sumter are this afternoon.  It is likely that conditions will become treacherous on area roads and power will likely lost in portions of the area later tonight.  Travel on area roads is not advised this afternoon and evening and responders will have to be selective in the types of calls that we answer throughout this event.  Here is the current situation as of 1330 Sunday.

Large swath fo the area is outline with watches and warnings as a large field of precip moves into the area.  This storm system extends back into the Texas area.  Conditions will improve for a while here with the clearing that is roughly over the I 59 corridor in South Mississippi.  However, this will not last long and heavier bands of precip will move in later in the evening. 

Temperatures at the surface are cold!  Where the precipitation is falling the hardest the temperature is falling faster (Northwest Mississippi).  We will likely see a slow fall in the temps this afternoon and evening and bottom out in the mid to upper twenties here tonight and early tomorrow. 

Brandon Radar as of 1330.

Fort Polk, LA radar as of 1330.  This is still going to move through the area.  Look at the strength fo the winds just off the coast. 

The expected accumulation numbers are still on track and it is likely that .25 to .50 inches of ice will be on just about everything by tomorrow morning.  This will cause quite a bit of travel problems and the electrical grid could see extensive damage.  Stay tuned!

The NWS has changed the Winter Storm Warning to an Ice Storm Warning for the counties immediately North and South of the US 80 corridor.  This follows the ideas and forecasts that have been expressed for the past few days.  Sleet has already started to fall across the region, but this activity will be short lived and the big show will start later this evening.  Reports from NWS Jackson at 0945 indicated that ice was beginning to accumulate from the heavier band that was moving across the area just north of Jackson.  The action should start here later in the afternoon.  The NWS Birmingham provides the following graphic…

The expected accumulation numbers have changed little and the following is from the NWS Jackson.

Birmingham has changed their forecast only slightly and ABC 33/40 (Spann) has modified the numbers to indicate the following.

A much more extensive report will be made this afternoon.  Stay tuned and be prepared for extensive power outages if the systems meets forecast expectations.

The National Weather Service has issued a Winter Storm Warning for the Sumter County area.  The graphic above shows and outline of the counties covered and shows the total trapazoid for the warning.  Further, the graphic indicates that the NWS expects 1-4 inches of snow in the US 80 corridor with up to .5 inches of ice accumulation in the area.  With this information in hand the warning must be taken seriously as this is a serious winter storm threat.  Snow and ice amounts of this size will bring about quite a bit of damage to trees and will likely cause widespread power outages where the ice is heaviest.  Remember that we still have some time for things to shake out and a final adjustment in excepted accumulations will be made when the system sets up over Mississippi.  Below is the model guidance from the 00Z (1800 local) forecast packages and it is clearly apparent that the models have changed little.

Forecast off the GFS at 06Z Sunday.  Still in good agreement with the others.

The NAM from the same time period.  The NAM still looks just like it did for the past 24.  The only thing to note is that it is a little drier this run.  (Scroll down to see the other model runs on the site for comparison)

The NAM surface look is still bothering me.  The freeze line at the surface is down near US98 and this is going to spell trouble for us.  We are hoping for the best, but crews have spent the day preparing for the worst.  We will continue to post updates throughout the event as quickly as possible. Email any questions to weather@cubafiredept.org

The Winter Storm Watch remains in place for the South Sumter area as of 12 Noon Saturday.  The primary weather forecasting models from the NWS remain in great agreement that the entire Southeast United States will be impacted by a major winter storm.  What type of precipitation and how much are never easy to forecast and most people will simply leave this on alone.  However, we are not forecasting anything, but putting the array of area forecasts before you so let’s get started.

As stated before the models are in good agreement that we will have the ingredients required to have a winter storm in the area.  Both the GFS and the NAM (two primary models for the NWS) are in good agreement on the position of the low and the temperature profile at 850MB.  Remember the freeze line on these charts are a very good indicator of the rain and snow line (not always correct, but generally very good).

The 12Z run of the GFS puts the freeze line just along or slightly south of the US 82 corridor.  The low is off the Mississippi coast and is spreading a nice field of precip back into the area.  This look means that the Sumter are would recieve no snow, but this is not the entire story.

The 12 Z run of the NAM has a much colder and bullish look with the precip.  The NAM has the critical freeze line along the US 80 corridor at midnight on Sunday.  This look puts the area firmly in the snow camp.  I would rather see the NAM correct that deal with ice, which is what the GFS suggests.  The next chart we will see is the surface chart from the GFS at the same time frame as the images above.

Notice at the surface that the freeze line is all the way down to the Highway 84 corridor and this is a classic look for ice storms in the area.  This is clearly the scenario that would be best avoided, but the GFS and a few other models have been solid on this idea for the past few days.  The burning question is how much of what might we expect and when.  The when appears to be from 1800 Sunday to 0600 Monday.  How much is covered by the following graphics.

The NWS Jackson calls for the above.  I would find this to be correct if the GFS is spot on.  The ice accumulations might be rather light if this is a freezing rain event only.

Birmingham has adjusted their snow numbers down greatly since Friday.  I am not exactly sure what they are seeing, but they seem to have a better handle on the ice potential than any of the others.

The Ice potential from Birmingham.  The numbers are coming up here.

Last but not least is James Spann’s forecast.  I beleive he has the better precip accumulation forecast and is being used as a ensemble between the two NWS offices.  Most troubling with Spann’s product is the bullish ice numbers. 

Bottom line…  We should prepare for a winter weather event that will likely involve significant ice accumulations for the area.  These preparations should involve charging of portable equipment, fueling trucks (generators/saws) and checking all other emergency backup power and such at repeater sites and the like.  If things still look as threatening as they do now we will likely have a briefing and IAP meeting at Cuba Town Hall or Siloam Station Sunday afternoon around 1500.  The next update should be made this evening around 2100 hrs.