Southern Storm to Bring Snow to Texas and New Mexico...

The latest water vapor satellite image (above) shows a middle and upper level low pressure center just off of the Northern coast of the Baja peninsula in Mexico.  This system will slowly move out toward the East over the next 48-60 hours, spreading snow to the lowlands of southern Mexico and southwest Texas, and light rain across much of the main body of the Lone Star State.

The most noteworthy aspect of the precipitation that will take place Thursday into Friday will no doubt be the the snow that will take place across southcentral and southeastern New Mexico into southwest Texas, including the El Paso area.

The latest run of the high resolution NAM computer model is forecasting widespread 2-4 inch snowfall amounts in this region, with localized amounts in excess of 6 inches as shown in yellow and red:

A narrow ribbon of light snow accumulation is also forecast for Northwestern portions of the Hill Country, mainly to the West of I-35.

A Winter Storm Watch is currently in effect for late tonight through Friday morning across the region shown in blue on the image below:

Travel will become hazardous on Thursday along I-10 from about Ft. Stockton on West to El Paso, so please plan accordingly if you have to use that route.

On the "warm" side of the system, widespread light rain will spread toward the East across Texas from Thursday through Saturday.  Unfortunately, much of the precipitation will be so light that it will be hard to measure.  Outside of the areas that receive snowfall, the best chance of accumulating moisture will take place along the southern border areas, as well as perhaps a narrow band of 0.25 to 0.50 inch amounts in the western Hill Country through Saturday morning:

Widespread cloudiness and light precipitation will keep temperatures well below seasonal normals across the region through Saturday as well, with a "bullseye" of temperatures at 25-30 degrees below normal across southwest Texas centered on 12 Noon CST this Friday:

For more information from 'The Original Weather Blog', including shorter, more frequent posts during rapidly changing weather events, please be sure to follow me on facebook and twitter:

 

If you are in need of highly customized, site specific weather forecasts and/or storm warnings for your business, school or event, be sure visit my professional webpage at WeatherGuidance.com.

A Look At Yesterday Evening's Snow in the Deep South...

The image above shows snow depth as estimated by satellite imagery and computer models across the middle and lower Mississippi River Valley region at 6am CST this morning.   This particular image is from the Interactive Snow Information site via NOAA.  Below is a slightly different (geographically speaking) representation via NOAA's National Snow Analysis Center:

As you can see on both of the images, there are 2 patches of heavier snow depth indicated (on the order of 4-8 inches):  the first over extreme northeastern Arkansas, and the second over southeastern Missouri.  In fact, storm reports indicate 8.0 inches of snow fell near Paragould and 6 inches of snow fell near Jonesboro, both in Arkansas.  A report of 4.5 inches of snow came in from Caruthersville, Missouri:

Yesterday evening I posted an image from the experimental HRRR forecast model, which was calling for locally heavy snow across much of this region yesterday evening and overnight.  Below is the accumulated snowfall forecast from that model valid at 6am CST this morning, the same time that the observations were taken on each of the 3 images above.  The image was produced by the model at 5pm CST on Monday, approximately 13 hours before the valid time:

As you can see, the model did an outstanding job forecasting the heavier snow band across extreme northeast Arkansas and southeast Missouri.  It correctly forecast 6-8 inches of snow across this region (darker yellow and orange colors on the image).


On the other side of the coin, the model over-forecast the magnitude of the snowfall in Memphis, calling for 3-4 inches (around 1 inch was reported in most areas).  Truth be told, had the ground been colder in Memphis, they would have had more significant accumulation (and this was pointed out in the posts that I made yesterday afternoon).


All in all, I'd say the HRRR performed quite well in this event, and if you ask any meteorologist, snowfall forecasts are among the toughest calls.  I plan to keep an eye on the performance of this model in other snow events this winter and will post any relevant updates and/or observations.


In fact, it looks like we'll have an opportunity to test out the model this weekend in the Plains.  Watch for a more detailed post on this impending winter storm later this evening...




If you enjoy reading 'The Original Weather Blog', please be sure to "like" our facebook page!

Update on Early Snowfall Across the Deep South...

The above image was just taken from the Memphis area radar. The small blue icons with snow flakes inside are recent snow depth reports. I've noted the snow depth in inches to the right of each icon.  As you can see, one half inch to around 1 inch of snow has fallen across portions of west-central Tennessee and northeast Arkansas so far.

The latest run of the GFS computer model is forecasting 3-4 inches of snow accumulation across this general area by Midnight CST this evening: 

The county-level, zoomed-in GFS based snowfall forecast images are not yet available from the latest run.  I'll post that image as soon as it becomes available.

This event will be the first time that we will have had the opportunity to evaluate the HRRR (High Resolution Rapid Refresh) model's performance during a snowfall episode.  Below is the latest image from that model, also valid Midnight CST later this evening:

I have highlighted the bright yellow patches of 6-8 inch snowfall that this particular model is forecasting (scale in inches at bottom of image).  The brighter green areas surrounding those heavier patches indicate a healthy 4-6 inch snowfall according to this model.  Again, I have not yet evaluated the HRRR during a snow event, so use this information with caution.  If nothing else, it should give us a good idea as to the general area(s) where the heavier snow is likely to take place, even if the magnitude (in inches of snowfall) is not 100% accurate.  It will be interesting to see how this model performs during the event.  Watch for later updates on this...

If you'd like to see a few photos of the snow as it falls across the region, please take a look at this post.  I'll continue to update it with more relevant photos as they come in...

If you enjoy reading 'The Original Weather Blog', please be sure to "like" our facebook page!

Let the Alabama/Mississippi/Tennessee Snow Games Begin...

***Updated to add another photo at 8pm CST:

Paragould, AR via twitter user "grantpickney"

***Updated to add more photos 6pm CST:

Ridgely, TN via twitter user "rukavin8"

Logan, AL via twitter user "spann"

--------------------------Original post below:

As the mid-afternoon rolls around, pictures of falling snow are starting to come in from across the Deep South. The first was taken by a twitter user near Jackson, TN:

via twitter user "goingsewcrazy" in Jackson, TN

This next image was just taken by a tower camera in Haleyville, AL:

via James Spann's Facebook Page

As you can see, the flake sizes are rather large, indicative of the heavy, wet snow that is falling across the region (with more to come).  If the ground were cold enough, snow would be piling up fast and furious across the region for sure.  The picture (as well as other reports) in the Jackson, TN area shows that snow is beginning to stick to some of the elevated and grassy surfaces.  After a few more hours of evaporative cooling, it should start to accumulate in other surrounding areas as well.  

The forecasts from earlier today still look on track as far as accumulation goes.  I'll post a more detailed update on that element of the situation later this afternoon...

If you enjoy reading 'The Original Weather Blog', please be sure to "like" our facebook page!

Southern Snow Event Still Setting Up for Tonight, then Northward on Tuesday...

***Welcome to readers referred by the "Capital Weather Gang"! While still relevant, this original post has been updated, in some cases via a new post or posts.  Please be sure to check the blog homepage for the latest information and updates.  Thanks again for visiting!


***Updated at 12:25 PM CST:
The latest GFS computer forecast model runs are in and there is no significant change to the idea of locally "heavier" snowfall amounts along the Mississippi / Alabama / Tennessee border areas tonight:

You can see that the computer model has edged the 1-2 inch accumulation band back Westward to now include the greater Memphis area.

I may not have made myself clear on this idea in my original post, but I would suggest that you pay more attention to the area in which the accumulating snow is being forecast by the model vs. the actual amount that is being forecast by the model at this time.

Based on what we're seeing right now, I would generally expect to see 1-3 inches of snow within (or near) the darker pink shaded area on the above image, and possibly as many as 2-4 inches within (or near) the light blue shaded area on the same image.  

I'll have a more detailed update under a new thread later today...

-------------------------------Original Post:

Right before Thanksgiving I made a post stating that snow would be a possibility across the Deep South and the Mississippi Valley region early this week.  The latest computer model runs continue to support this forecast, and we are now able to be more specific as to the location and magnitude of the event as well.


Its important to keep in mind that all things are relative.  What may not be a big deal to New York City (snowfall wise) can be quite a big deal indeed to folks in the Deep South, where just an inch of snow can seemingly bring commerce to a near halt in some areas.


Below are the latest GFS computer model forecasts of snow depth valid at 6am CST on Tuesday and 6am CST on Wednesday:

I underlined the words "snow depth" in the last paragraph to illustrate a point.  The ground across the Deep South and mid-Mississippi Valley region is warm, which will have a significant impact on the accumulation of snow.  In some areas, snow will fall at a rate that would normally accumulate very rapidly given cold ground conditions, but in this case, much of the snow will melt before beginning to accumulate.  This is obviously good news for those who have to drive across this region tonight and Tuesday, but is bad news for you snow fans out there.

Despite the relatively warm ground conditions, it appears that snow will be able to accumulate across portions of the region tonight and early Tuesday.  Lets take a closer look at the GFS model snow depth forecast centered on the Memphis area on the image below:

Most of the snow in areas on the above image would fall during the overnight hours tonight and early Tuesday morning.  As you can see, the model is forecasting a fairly widespread swath of 2-3 inch snows immediately East of Memphis, with a small 3-4 inch bullseye to the Northeast of town.  This will be surrounded by a larger area of 1-2 inches of snow covering Northern portions of Mississippi and Alabama and into western Tennessee.

By Tuesday afternoon and evening, snows are forecast to spread North/Northeastward into portions of Kentucky, Indiana and Illinois, then reaching Michigan by late evening and into Tuesday night (please refer back to  the 2nd image from the top of the post).  Due to colder ground temperatures and heavier snowfall rates in this region, some significant accumulations are likely across portions of Michigan and northern Indiana, as indicated by the latest GFS forecast below, which is zoomed-in on the Michigan/Indiana border region:

As you can see, the model is forecasting as much as a foot of snow across portions of southwest Michigan by Wednesday morning.  I am confident that widespread snows of 6-8 inches are likely in this region, with localized amounts near 10 inches.  The model may turn out to be correct in forecasting amounts near one foot, but I think that will be on the more extreme end of the scale based on what we're seeing right now.

If you enjoy reading 'The Original Weather Blog', please be sure to "like" our facebook page!