Archive for January 16th, 2013
The winter storm watches have been reconfigured in the last hour by the National Weather Service.
Here is the latest winter weather alert map graphic.
Here is a look at the deep, cold core upper low that will swing through Alabama tomorrow….
After a peek at late model data tonight, don’t see much reason to change our ongoing forecast…
Some points to consider before going to bed….
*As I have stated here in recent days, we have a limited skill set in dealing with snow output from cold core upper lows like this. No two systems act the same, and I can almost guarantee you there will be surprises. Some of you will get more snow than you expect, and others will see nothing more than a flake or two. There is very little skill in identifying the exact placement of the heaviest band of snow.
*No doubt the best chance of the higher accumulation will be across the high terrain of East and Northeast Alabama. I bet Dave Baird on the air tonight we will see five inches on the ground at Cheaha State Park. But, keep in mind the elevation there is 2,407 feet. It will be fun to watch our SKYCAM there tomorrow.
*Snow will begin just before sun-up over far West Alabama, and progress east during the day. Snow should begin in Tuscaloosa in the 5:00 to 7:00 a.m. time frame… Birmingham by 8:00 a.m….. and Anniston/Gadsden by 9:00 a.m. Keep in mind these are rough estimates and could change. All of the snow will be over mid to late afternoon as the upper low moves quickly to the northeast.
*I still believe that we won’t have any serious travel issues tomorrow. Even where 2 inches of snow accumulates on grass, roads will be just wet. The ground and infrastructure is warm, and surface temperatures tomorrow should remain above freezing throughout the day. It is very hard for Alabamians to believe this when snow begins to fall heavily, but even with the heavier snow bursts, roads will be wet. But, remember, we have lots of wrecks around here on rainy days, so take it easy even with just wet roads.
*If any moisture lingers tomorrow night, there could be a touch of “black ice” in spots on bridges and overpasses. But, most of the moisture will evaporate by then.
*In the overall scheme of things, this is a “good” snow setup since we don’t expect any real travel issues, and many places across North-Central Alabama will have enough snow for a good snow ball fight, or maybe even enough for a snow man.
*For any school delays, please see the ABC 33/40 site.
I will have a fresh discussion and a new Weather Xtreme video here posted by 6:30 a.m. tomorrow. Stay tuned…
We continue to pore over information coming into the Weather Office tonight concerning tomorrow’s well advertised snow event. The models started picking up on this thing last weekend, and it seems to be panning out tonight.
Here are my thoughts shortly after 8:
Rain will change to snow tomorrow from west to east starting in the morning.
The timing looks like this:
…9 a.m. : A line from Haleyville/Fayette/Tuscaloosa/Demopolis. West of that it could start as early as 6 a.m.
…Noon: A line from Holly Pond to Pell City to Billingsley. This would put the changeover in the Birmingham area around 10:30-11 a.m.
…1:30: Gadsden to Anniston to Alex City. Areas east of there after that.
The noon run of the GFS expanded the area of 1″+ snow a little further south. That is in very good agreement with the morning run of the European. The NWS Birmingham added Greene, Hale, Perry and Sumter Counties to the Winter Storm Watch.
A Winter Storm Watch means conditions are favorable for winter weather conditions to develop. Like a tornado or severe thunderstorm watch. For the Birmingham NWS area means there is a 50% or greater confidence that the area could receive 2 or more inches of snow.
Here is the latest forecast snow depth chart for 6 p.m. tomorrow night from the GFS model:
Zooming in a little closer:
Areas inside a polygon in Alabama from Hamilton to Huntsville eastward to the Georgia border southward to Roanoke then westward to Sylacauga and Butler should see 1/2 to 1 inch of snow.
Most of this snow will accumulate on grassy areas and roofs.
Slightly heavier snow, between 1-2 inches should fall in a polygon from Sulligent to Decatur to Bridgeport to Heflin to Pell City to the Birmingham Metro on to Reform in Pickens County.
in this area, most of it will accumulate on roofs and grassy areas as well. But where the heavier snow sets up, it may fall fast enough to accumulate on roads, especially bridges and overpasses.
Finally, 2-3 inches of snow looks possible for areas from Cullman to Scottsboro to Centre to Springville to Locust Fork. Here snow may have a chance to accumulate on roads. Some spots in this zone may well see 4 or more inches.
Of course, we are basing this on the best model data that we have tonight. The track of the upper level low and the cold air aloft it is bringing will determine where the heaviest snowfall may fall. That cooling will happen on the back side of the moisture as it is departing, so there will be a narrow window (less than four hours) for snow to fall.
We will have to watch where the heaver snow sets up on radar during the morning and then we can fine tune the forecasts. It will be interesting. And there certainly will be some surprises…and disappointments.
Scroll down for James’ afternoon discussion about the snow potential.
Here is the text of the Winter Storm Watch just issued by the NWS Birmingham.
These are the counties included in the watch in Central Alabama.
Please pay attention to later information on the winter weather situation right here on the AlabamaWX.com blog throughout the late afternoon, evening, overnight and tomorrow.
An all new edition of the ABC 33/40 Weather Xtreme video is available in the player on the right sidebar of the blog. You can subscribe to the Weather Xtreme video on iTunes by clicking here.
SNOW DAY: A deep, cold core upper low will pass right over North-Central Alabama tomorrow, and should bring our first snow event of the winter to our state. Before I get into the details here, just a reminder… we don’t have very good skill at handling snow amounts, or placement, under one of these. Cold core upper low, weatherman’s woe. So, expect some surprises tomorrow as the event unfolds.
The National Weather Service in Huntsville has issued a winter storm watch for Cullman, Lawrence, Limestone, Morgan, Madison, Jackson, and DeKalb Counties for this event. We have not heard from the Birmingham NWS office, but they will issue either a winter storm watch, or a winter weather advisory by the time you read this, most likely.
This is what we expect…
*TIMING: Snow begins over West Alabama early tomorrow morning, in the 3:00 a.m. to 5:00 a.m. range. The big snow shield under the cold core upper low will move steadily east during the morning; snow should begin in Tuscaloosa in the 5:00 to 7:00 a.m. time frame… Birmingham by 8:00 a.m….. and Anniston/Gadsden by 9:00 a.m. Keep in mind these are rough estimates and could change. All of the snow will be over mid to late afternoon as the upper low moves quickly to the northeast.
*PLACEMENT: There could be some light accumulation on grass as far south as Linden, Montgomery, and Roanoke. See our graphic below for the current thinking.
*AMOUNTS: Very tricky. As you can see, we are going two inches or less for most places, with potential for more than 2 inches over East and Northeast Alabama. Across higher terrain, I think we could see a 5 inch or greater total somewhere like Mount Cheaha or Mentone. The best chance of seeing over three inches of snow will come above 1,000 feet. But again, we don’t have much skill in handling these cold cores, and this could change as we get into the event tomorrow. The ground is relatively warm, which will limit accumulation.
*TRAVEL: Accumulation should be mostly on grassy areas, leaving roads just wet with temperatures holding above freezing all day. I honestly don’t think there will be any serious travel issues tomorrow, even though it might look like a blizzard is coming down at times. Temperatures will hover in the mid 30s as the snow falls.
The exception will be higher terrain across East and Northeast Alabama, where slippery roads could become an issue, especially over 1,000 feet. This means places like Sand Mountain, Lookout Mountain, Cheaha State Park, etc.
Also, temperatures will go below freezing tomorrow night, so any standing water could freeze, meaning a few icy spots on bridges. But, most of the moisture should evaporate quickly.
Take a few minutes to watch the Weather Xtreme video for all the graphics, maps, and details.
SUNSHINE RETURNS: Many of you will be excited to see the sun on Friday. Our weather will be dry Friday through Sunday with seasonal temperatures; highs mostly in the 50s and lows mostly in the 30s, although colder pockets will see 20s early Friday and Saturday morning.
NEXT WEEK: I still think we have a good shot of getting some Arctic air down in here on Tuesday and Wednesday. The latest deterministic runs of the GFS have been warmer, but the ECMWF still looks very cold, and considering the depth of the cold air over Canada, I believe the colder solution is correct. There is a chance we won’t get out of the 30s Tuesday, and teens are very possible by daybreak Wednesday. The week will be dry with no snow.
VOODOO MISCHIEF: The GFS still hints at some winter weather mischief before the month is over… looks like there might be winter storms, or rumors of winter storms as a cold, unsettled pattern sets up. See the Weather Xtreme video for the details.
WEATHER BRAINS: Don’t forget you can listen to our weekly 90 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40.
CONNECT: You can find me on all of the major social networks…
I had a great time today seeing the pre-school kids at First Baptist Church of Alabaster… be looking for them on the Pepsi KIDCAM today at 5:00 on ABC 33/40 News! The next Weather Xtreme video will be posted here by 7:00 a.m. tomorrow… and stay tuned for updates tonight as our system to the west gets closer.
The NWS Huntsville has issued a winter storm watch beginning late tonight (at 3 a.m. Thursday morning) for counties in the Tennessee Valley of North Alabama and at 6 a.m. Thursday for their Northeast Alabama Counties.
No word from the NWS Birmingham on what their intentions are, but here is the latest thinking from the morning run of the GFS.
LATE NOTE 1:41: Look for the NWS to issue some sort of winter weather advisory or watch when they issue their afternoon forecast package in a couple of hours. They are currently evaluating all of the morning data.
BACK TO ORIGINAL POST
The new GFS snow output continues with the thought of an accumulating snow for parts of North and Central Alabama as a strong upper level low moves across.
It indicates he best chance for accumulating snows will be northeast of Birmingham, but a dusting to 1/2 inch could affect areas from Birmingham to the Southwest, in keeping with James’ earlier graphic. It indicates areas from northeast of Birmingham could see 1-2 inches of snow by tomorrow evening. Here is the graphic for snow depth at 6 p.m. tomorrow evening. Some light accumulations over West Central Alabama would have already melted by then.
The snow should mainly accumulate on grassy areas, but locations that see 1 to 2 inches of snow could see it stick on roads as well.
And as we always warn, upper level lows bring their own surprises with them, generally in the form of a few quick, heavy snow accumulations, so keep that in mind.
James will have a complete update around 3 p.m. with the Weather Xtreme Video.