I often get questions about terms and abbreviations I use when writing discussions of long range weather. Letters like “NAO”, “AO”, “PNA”, and “MJO” often appear, and I am very much guilty of not explaining what I am taking about.

All of these letters represent upper air flow patterns associated with teleconnections, the idea that weather changes at one location might be related to weather changes at other remote locations around the Earth. People have been fascinated since at least the latter part of the nineteenth century by the prospect of identifying linkages among weather changes in various parts of the globe. There is no doubt everything around the globe is linked. Whenever I see extreme weather (snow, rain, ice, droughts, etc) in places like Asia and Europe, I try to tie it in to the possible impact on the situation here in the southern U.S.

The NAO is the North Atlantic Oscillation. In a negative NAO phase, the North Atlantic jet stream is shifted south of normal over the eastern U.S., and the upstream polar jet stream coming southward from Canada is stronger than normal. These conditions favor more frequent and more intense cold-air outbreaks across the eastern and southern U.S. Jet streams also determine where winter storms will form, and how intense they will be. A negative phase of the NAO and a southward shift of the North Atlantic jet stream sometimes means more frequent winter storms for the eastern and southern United States. And, sometimes true Arctic air can be tapped coming over the North Pole, making for some big time cold temperatures down this way.

In contrast, the positive phase of the NAO features a northward shift of the North Atlantic jet stream pattern over the eastern U.S., and a reduced flow of cold air from Canada. Looks like the NAO is going negative in February… so stay tuned!

Learn more on teleconnections in this excellent paper:

http://blue.atmos.colostate.edu/publications/pdf/CB-48.pdf

Nothing serious, but snow flurries are being reported in a few spots in North Alabama tonight.

3340 viewer at Wellington reports flurries around 9:30. That is between Gadsden and Anniston.

Also flurries near Hackleburg in NW Alabama. Person there posted some pictures of the flakes on the 3340 blog.

Radar shows some scattered flurries, or snow showers moving toward the ESE. That may also be light rain showers.

A late report from someone in Guin indicates that flurries have been occurring in that area for about an hour. Pretty to look at but none accumulating.

Again, no problem with the flurries.

The extensive rain area has shifted east over into Georgia and a lesser amount along the Alabama-Georga border.

However, scattered light precipitation still exists at 7:30 over North Alabama. Light snow reported at Muscle Shoals in NW Alabama.

Turning sharply colder.

SPOT REPORTS AT 7 PM CST

32 with light snow in Nashville (wind chill 25)
32 light snow at Jackson, Tenn.
36 with flurries at Muscle Shoals (wind chill 25)
37 with light rain at Tupelo, Miss.
43 cloudy in Birmingham
42 cloudy in Tuscaloosa
30 light snow in Clarksville, Tenn., (Ft. Campbell area)

The flurries across North Alabama tonight should not cause any problem. Ground too wet and too warm.

A late rainfall update from James Spann
1.54 in Greystone Cove (North Shelby County)

It happened today.

As of this morning, Birmingham had a rainfall deficit of almost an inch already for 2006.

But today, 1.64 inches fell at the airport.

So now, we are 0.52 of an inch ahead of the game.

Sure wush we could have shared some of that rain with the Fort Worth-Dallas area and Oklahoma City.

Those cities did not get any rain today.

And grass fires were again underway at Fort Worth.

Every square mile of Alabama got a soaking today. First time that has happened to this extent in a long, long time. This is a lengthy list of rainfall amounts since people from all parts of the state like to know how much rain they got. In some cases there is more than one report from the same city. But in some places we get more than one report:

1.37 inches in Crossville
1.13 in Cullman
2.03 in Decatur
0.57 at Fort Payne
1.97 at Huntsville Airport
2.46 at Muscle Shoals
1.51 in NE Trussville
0.52 at Orange Beach
1.40 at Demopolis
1.21 in Ashland
1.52 in Alexander City
1.35 in Anniston
1.49 at Smith Dam
1.07 at Ashville
1.58 at Blue Pond (Cherokee)
1.14 at Bald Rock (near Cook Springs, St. Clair County)
1.49 at Blountsville
1.42 at Bankhead Dam
1.14 at Logan Martin Dam
1.06 at Childersburg
1.41 at Clanton
1.33 at Lay Dam
0.98 in Collinsville
1.14 in Cordova
0.73 in Centre
1.45 at Carbon Hill
1.36 at Yates Dam
1,04 at Dearmanville
1.15 at Ellisville (Cherokee County)
0.94 at Fort Payne
0.91 at Gadsden
1.42 at Gaylesville (Cherokee County)
1.52 at Gorgas
1.42 at Hackneyville (Tallapoosa County)
1.38 at Horseshoe Bend
1.15 at Hollins (Clay County)
1.54 at Haleyville
1.16 at Jackson Shoals (Talladega County)
1.33 at Jasper
1.16 at Manchester (Walker County)
1.10 at Harris Dam
0.87 at Mt. Cheaha
1.11 at Newell (Randolph County)
1.00 at Oak Grove (West Jefferson County)
1.28 in Oneonta
1.37 in Pell City
0.87 at Henry Dam (Calhoun County)
0.73 at Rock Run (Cherokee County)
0.96 at Roanoke
1.19 at Sayre
0.71 at Sylacauga
1.33 at Steele (North St. Clair County)
1.30 at Holt (east edge of Tuscaloosa)
1.28 at Martin Dam
1.59 at Trafford
1.43 at Mitchell Dam
0.99 in Wadley
1.54 at Jordan Dam
1.27 at Anniston
0.80 at Auburn
1.64 at Birmingham Airport
1.28 at Shelby County Airport (NWS Office)
0.61 in Dothan
1.55 in Evergreen
0.92 in Mobile
1.47 in Montgomery
1.22 in Troy
1.06 at Tuscaloosa Airport
1.48 at Pinson

Scan down to see an earlier post for the amounts from the 3340 WeatherNet

Late this afternoon the main rain had shifted over into East Central and Southeast Alabama.

However, an extensive area of light rain lingers over much of the state.

Meanwhile, colder air is flowing in from the west but has been sort of taking its time.

Some sample 5 pm reports:

44 in Tuscaloosa, 8 degrees colder than Birmingham
52 in Birmingham with winds gusting to 29 mph
33 in Jackson, Tenn., with light snow
34 in Memphis with light snow
40s in both Decatur and Huntsville with brisk west winds

Doppler estimates show that part of Northwest Alabama had more than three inches of rain today. Mainly in Eastern Marion County and Western Winston County.

Before all the rain ends late tonight, we may have a changeover to flurries. No danger of any problems.

Around 6:30 tonight, we will post a more comprehensive rainfall list. We will have lots of reports at that time.

Meanwhile, some up to the minute totals:

1.33 inches in Helena (from Brian Peters)
1.81 at the 3340 Weather office (from James Spann)

...and from the 3340 WeatherNet

1.03 inches in Gadsden
1.80 in Hamilton
1.20 at Tuscaloosa
1.09 at Birmingham (Legion Field)
0.74 in Talladega
1.15 in Downtown Anniston (Noble Street)

Here is a quick update on the Alabama weather situation:

The temperature has dropped to 44 in Muscle Shoals... Both Tupelo and Columbus, MS are down to 41.

Jackson, Tennessee has light snow and 34 degrees.

Updated rain totals:

Hamilton 1.76"
ABC 33/40 Studio in Riverchase: 1.65"
Clanton 1.28"
Tuscaloosa 1.11"
Legion Field (Birmingham) 1.01"
Anniston 0.96"
Gadsden 0.85"
Talladega 0.61"

The Tuesday afternoon map discussion video is on the server:

http://beta.abc3340.com/weather/video.hrb

Look like our projections for 1 to 2 inches of rain for the state were right on the money. Here at the ABC 33/40 Studio in Riverchase, I now have 1.35" as of 2:04 p.m. CST. Hamilton is nearing two inches... J.B. will have a more complete list shortly.

TONIGHT: The colder air is moving into northwest Alabama right now; Muscle Shoals is down to 47 degrees, and Memphis is at 37. We will be in the 30s tonight, and all models show enough lingering moisture for a few flurries over the northern half of the state. Quite frankly, some of the models are spitting out 0.05" of liquid precipitation when the 850 temp (5,000 feet off the ground) is -8 degrees (C). That would suggest 1/2 inch of  snow using a standard 10 to 1 conversion. But, soil temperatures are in the 40s, and most of the snow will simply melt that falls. However, car tops might turn white, especially over parts of Northeast Alabama. Counties like Cherokee, DeKalb, Jackson. It will be very interesting to watch the weather develop tonight as the cold air moves in.

I am not saying there will be light snow everywhere, but you have to mention at least a chance of a little light snow or flurries tonight based on what is happening and the model output from 12Z. If we do see light snow, there should be no travel problems at all.

The sun returns tomorrow and Thursday. I still think MOS numbers are too warm for Thursday morning; I expect a light freeze for most places.

WEEKEND SYSTEM: Next chance of showers and storms will come late Friday night into the day Saturday. The 12Z GFS is a little stronger, but I still don't expect a major problem with severe weather or flooding. Sunday should be dry and pleasant; there not really any cold air behind Saturday's system.

LONG RANGE: Still looks like we get wet about every three to four days between now and the end of the month. Uh oh... the NAO trends negative as we begin February. See J.B.'s post below on the brutally cold air up in the Polar region. Stay tuned!

Sure enjoyed speaking today at a meeting of the Alabama Independent Insurance Agents, Inc.... needless to say they sure have vested interest in weather.

I also enjoyed having my friend Madison Beck and her parents at our office yesterday. Madison is a first grader at McAdory Elementary, and is fighting leukemia. They are a member of Hunter Street, and Madison is one of the kids I teach in Outfitters 2:52 every Sunday. I encourage you to pray for Madion and her family; their home burned to the ground before Christmas. Their attitude and faith is really something. Read about their story here.

I will have the next video ready by 7:00 a.m. tomorrow!

Seems like it is raining over the whole, wide world.

It is raining on virtually all of the Alabama world.

Almost every square mile getting wet.

At 2 pm, heaviest rain extended from Perry County north through Bibb, Jefferson, Eastern Walker and St. Clair County.

Rain will be getting heavier again shortly in the Birmingham area.

Colder air now entering Extreme West and NW Alabama.

Should still be enough moisture left behind for a changeover to snow flurries before the precipitation ends.

Maybe as far south as Birmingham.

Better chance over the north and NE sections.

Not out of the question that car tops and grassy areas could become partially white, especially Extreme north and NE late tonight.

Not enough to cause any problems anywhere.

3340 Weathernet rainfall through 2 pm:

1.27 inches at 3340 in Riverchase
1.71 in Hamilton
1.03 in Tuscaloosa
1.05 at Clanton
0.42 in Talladega
0.51 in Gadsden
0.78 in Anniston

Raining over 90% of Alabama early this afternoon.

Only the extreme SE still has not gotten wet.

The initial line of heavy showers is now over East Central Alabama and down into the SE part of the state. However, a broad zone of moderate to heavy rain is over NW and West-Central Alabama. This is especially true from Winston County down through the west parts of both Walker and Tuscaloosa Counties and then into West-Central Alabama through Pickens, Greene and Sumpter Counties.

Based on radar estimates, as much as 3.70 inches of rain has fallen today over Eastern Marion County and NW Winston County in NW Alabama.

These actual measurements through 12:00 Noon:

1.02 inches at the 33/40 weather office in Riverchase
1.09 at Tuscaloosa Airport
1.07 at Birmingham Airport
1.24 in Decatur
0.82 at Montgomery's Dannelly Field
0.62 at Shelby County Airport
0.59 at Anniston Airport
0.92 at Evergreen
0.58 at Mobile Regional Airport

There were several severe thunderstorm warnings down in South-Central Alabama during the late morning and midday.

Colder air is still poised to the west of Alabama in Mississippi and West Tennessee waiting to move in.